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Primary saccades are often followed by small secondary saccades, which are generally thought to reduce the distance between the saccade endpoint and target location. Accumulated evidence demonstrates that secondary saccades are subject to various influences, among which retinal feedback during postsaccadic fixation constitutes only one important signal. Recently, we reported that target eccentricity and an orientation bias influence the generation of secondary saccades. In the present study, we examine secondary saccades in the absence of postsaccadic visual feedback. Although extraretinal signals (e.g., efference copy) have received widespread attention in eye-movement studies, it is still unclear whether an extraretinal error signal contributes to the programming of secondary saccades. We have observed that secondary saccade latency and amplitude depend on primary saccade error despite the absence of postsaccadic visual feedback. Strong evidence for an extraretinal error signal influencing secondary saccade programming is given by the observation that secondary saccades are more likely to be oriented in a direction opposite to the primary saccade as primary saccade error shifts from target undershoot to overshoot. We further show how the functional relationship between primary saccade landing position and secondary saccade characteristics varies as a function of target eccentricity. We propose that initial target eccentricity and an extraretinal error signal codetermine the postsaccadic activity distribution in the saccadic motor map when no visual feedback is available.
Ten ice-sheet models are used to study sensitivity of the Greenland and Antarctic ice sheets to prescribed changes of surface mass balance, sub-ice-shelf melting and basal sliding. Results exhibit a large range in projected contributions to sea-level change. In most cases, the ice volume above flotation lost is linearly dependent on the strength of the forcing. Combinations of forcings can be closely approximated by linearly summing the contributions from single forcing experiments, suggesting that nonlinear feedbacks are modest. Our models indicate that Greenland is more sensitive than Antarctica to likely atmospheric changes in temperature and precipitation, while Antarctica is more sensitive to increased ice-shelf basal melting. An experiment approximating the Intergovernmental Panel on Climate Change's RCP8.5 scenario produces additional first-century contributions to sea level of 22.3 and 8.1 cm from Greenland and Antarctica, respectively, with a range among models of 62 and 14 cm, respectively. By 200 years, projections increase to 53.2 and 26.7 cm, respectively, with ranges of 79 and 43 cm. Linear interpolation of the sensitivity results closely approximates these projections, revealing the relative contributions of the individual forcings on the combined volume change and suggesting that total ice-sheet response to complicated forcings over 200 years can be linearized.
Deep into the second half of the twentieth century the traditionalist definition of India as a country of villages remained dominant in official political rhetoric as well as cultural production. In the past two decades or so, this ruralist paradigm has been effectively superseded by a metropolitan imaginary in which the modern, globalised megacity increasingly functions as representative of India as a whole. Has the village, then, entirely vanished from the cultural imaginary in contemporary India? Addressing economic practices from upper-class consumerism to working-class family support strategies, this paper attempts to trace how 'the village' resurfaces or survives as a cultural reference point in the midst of the urban.
Effects of intraspecific and community density on the lifetime fecundity of long-lived shrubs
(2013)
Intra- and interspecific density dependence has profound consequences for plant population and community dynamics. In long-lived plants, however, lifetime patterns and mechanisms of density dependence are difficult to study. Here, we examine effects of intraspecific and community density on the lifetime fecundity of two long-lived shrub species from South African Fynbos: Protea repens (animal-pollinated, hermaphroditic) and Leucadendron rubrum (wind-pollinated, dioecious). Both species are serotinous, retaining seeds in cones until fire kills the mother plant. We measured lifetime fecundity as the product of cone number, proportion of cones that are not damaged by predation and seed set (fertile seeds per intact cone). Intraspecific and community densities were quantified by counting individuals of target species and all Proteaceae in small- and large-scale neighbourhoods (10 m and 50 m radius) around each focal individual. Additionally, we determined the age and size of focal individuals. We found that lifetime fecundity of the wind-pollinated L rubrum is density independent. In contrast, the lifetime fecundity of the animal-pollinated P. repens increases with large-scale intraspecific density and shows a hump-shaped relationship to large-scale community density. Community density has a hump-shaped effect on seed set (probably through partial absence of generalized pollinators at low and competition for pollinators at high densities) and negatively affects cone number per individual. For both species, plant age decreases seed set while increasing lifetime fecundity. The qualitative differences in the density dependence of lifetime fecundity may arise from differences between animal and wind pollination. In particular, interactions with generalized animal pollinators may cause community-level Allee effects with profound consequences for the future dynamics of long-lived plant populations and communities.
Calcium phosphate nanofibers with a diameter of only a few nanometers and a cotton-ball-like aggregate morphology have been reported several times in the literature. Although fiber formation seems reproducible in a variety of conditions, the crystal structure and chemical composition of the fibers have been elusive. Using scanning transmission electron microscopy, low dose electron (nano) diffraction, energy-dispersive X-ray spectroscopy, and energy-filtered transmission electron microscopy, we have assigned crystal structures and chemical compositions to the fibers. Moreover, we demonstrate that the mineralization process yields true polymer/calcium phosphate hybrid materials where the block copolymer template is closely associated with the calcium phosphate.
A novel procedure has been developed to conduct cell structure measurements on increment core samples of conifers. The procedure combines readily available hardware and software equipment. The essential part of the procedure is the application of a confocal laser scanning microscope (CLSM) which captures images directly from increment cores surfaced with the advanced WSL core-microtome. Cell wall and lumen are displayed with a strong contrast due to the monochrome black and green nature of the images. Consecutive images are merged into long images representing entire increment cores which are then analysed for cell structures in suitable software.
A problem encountered by many distributed hydrological modelling studies is high simulation errors at interior gauges when the model is only globally calibrated at the outlet. We simulated river runoff in the Elbe River basin in central Europe (148 268 km(2)) with the semi-distributed eco-hydrological model SWIM (Soil and Water Integrated Model). While global parameter optimisation led to Nash-Sutcliffe efficiencies of 0.9 at the main outlet gauge, comparisons with measured runoff series at interior points revealed large deviations. Therefore, we compared three different strategies for deriving sub-basin evapotranspiration: (1) modelled by SWIM without any spatial calibration, (2) derived from remotely sensed surface temperatures, and (3) calculated from long-term precipitation and discharge data. The results show certain consistencies between the modelled and the remote sensing based evapotranspiration rates, but there seems to be no correlation between remote sensing and water balance based estimations. Subsequent analyses for single sub-basins identify amongst others input weather data and systematic error amplification in inter-gauge discharge calculations as sources of uncertainty. The results encourage careful utilisation of different data sources for enhancements in distributed hydrological modelling.
The relevance of biological Si cycling for dissolved silica (DSi) export from terrestrial biogeosystems is still in debate. Even in systems showing a high content of weatherable minerals, like Cambisols on volcanic tuff, biogenic Si (BSi) might contribute > 50% to DSi (Gerard et al., 2008). However, the number of biogeosystem studies is rather limited for generalized conclusions. To cover one end of controlling factors on DSi, i.e., weatherable minerals content, we studied a forested site with absolute quartz dominance (> 95 %). Here we hypothesise minimal effects of chemical weathering of silicates on DSi. During a four year observation period (05/2007-04/2011), we quantified (i) internal and external Si fluxes of a temperate-humid biogeosystem (beech, 120 yr) by BIOME-BGC (version ZALF), (ii) related Si budgets, and (iii) Si pools in soil and beech, chemically as well as by SEM-EDX. For the first time two compartments of biogenic Si in soils were analysed, i.e., phytogenic and zoogenic Si pool (testate amoebae). We quantified an average Si plant uptake of 35 kg Si ha(-1) yr(-1) - most of which is recycled to the soil by litterfall - and calculated an annual biosilicification from idiosomic testate amoebae of 17 kg Si ha(-1). The comparatively high DSi concentrations (6 mg L-1) and DSi exports (12 kg Si ha(-1) yr(-1)) could not be explained by chemical weathering of feldspars or quartz dissolution. Instead, dissolution of a relictic, phytogenic Si pool seems to be the main process for the DSi observed. We identified canopy closure accompanied by a disappearance of grasses as well as the selective extraction of pine trees 30 yr ago as the most probable control for the phenomena observed. From our results we concluded the biogeosystem to be in a transient state in terms of Si cycling.
Mean age of carbon in fine roots from temperate forests and grasslands with different management
(2013)
Fine roots are the most dynamic portion of a plant's root system and a major source of soil organic matter. By altering plant species diversity and composition, soil conditions and nutrient availability, and consequently belowground allocation and dynamics of root carbon (C) inputs, land-use and management changes may influence organic C storage in terrestrial ecosystems. In three German regions, we measured fine root radiocarbon (C-14) content to estimate the mean time since C in root tissues was fixed from the atmosphere in 54 grassland and forest plots with different management and soil conditions. Although root biomass was on average greater in grasslands 5.1 +/- 0.8 g (mean +/- SE, n = 27) than in forests 3.1 +/- 0.5 g (n = 27) (p < 0.05), the mean age of C in fine roots in forests averaged 11.3 +/- 1.8 yr and was older and more variable compared to grasslands 1.7 +/- 0.4 yr (p < 0.001). We further found that management affects the mean age of fine root C in temperate grasslands mediated by changes in plant species diversity and composition. Fine root mean C age is positively correlated with plant diversity (r = 0.65) and with the number of perennial species (r = 0.77). Fine root mean C age in grasslands was also affected by study region with averages of 0.7 +/- 0.1 yr (n= 9) on mostly organic soils in northern Germany and of 1.8 +/- 0.3 yr (n = 9) and 2.6 +/- 0.3 (n = 9) in central and southern Germany (p < 0.05). This was probably due to differences in soil nutrient contents and soil moisture conditions between study regions, which affected plant species diversity and the presence of perennial species. Our results indicate more long-lived roots or internal redistribution of C in perennial species and suggest linkages between fine root C age and management in grasslands. These findings improve our ability to predict and model belowground C fluxes across broader spatial scales.
Predictions of marine ice-sheet behaviour require models able to simulate grounding-line migration. We present results of an intercomparison experiment for plan-view marine ice-sheet models. Verification is effected by comparison with approximate analytical solutions for flux across the grounding line using simplified geometrical configurations (no lateral variations, no buttressing effects from lateral drag). Perturbation experiments specifying spatial variation in basal sliding parameters permitted the evolution of curved grounding lines, generating buttressing effects. The experiments showed regions of compression and extensional flow across the grounding line, thereby invalidating the boundary layer theory. Steady-state grounding-line positions were found to be dependent on the level of physical model approximation. Resolving grounding lines requires inclusion of membrane stresses, a sufficiently small grid size (<500 m), or subgrid interpolation of the grounding line. The latter still requires nominal grid sizes of <5 km. For larger grid spacings, appropriate parameterizations for ice flux may be imposed at the grounding line, but the short-time transient behaviour is then incorrect and different from models that do not incorporate grounding-line parameterizations. The numerical error associated with predicting grounding-line motion can be reduced significantly below the errors associated with parameter ignorance and uncertainties in future scenarios.
Among the climatological events of the last millennium, the Northern Hemisphere Medieval Climate Anomaly succeeded by the Little Ice Age are of exceptional importance. The origin of these regional climate anomalies remains a subject of debate and besides external influences like solar and volcanic activity, internal dynamics of the climate system might have also played a dominant role. Here, we present transient last millennium simulations of the fully coupled model of intermediate complexity Climber 3a forced with stochastically reconstructed wind-stress fields. Our results indicate that short-lived volcanic eruptions might have triggered a cascade of sea ice ocean feedbacks in the North Atlantic, ultimately leading to a persistent regime shift in the ocean circulation. We find that an increase in the Nordic Sea sea-ice extent on decadal timescales as a consequence of major volcanic eruptions in our model leads to a spin-up of the subpolar gyre and a weakened Atlantic meridional overturning circulation, eventually causing a persistent, basin-wide cooling. These results highlight the importance of regional climate feedbacks such as a regime shift in the subpolar gyre circulation for understanding the dynamics of past and future climate.
Huntington disease (HD), a dominantly inherited neurodegenerative disorder caused by the expansion of a CAG-encoded polyglutamine (polyQ) repeat in huntingtin (Htt), displays a highly heterogeneous etiopathology and disease onset. Here, we show that the translation of expanded CAG repeats in mutant Htt exon 1 leads to a depletion of charged glutaminyl-transfer RNA (tRNA) Gln-CUG that pairs exclusively to the CAG codon. This results in translational frameshifting and the generation of various transframe-encoded species that differently modulate the conformational switch to nucleate fibrillization of the parental polyQ protein. Intriguingly, the frameshifting frequency varies strongly among different cell lines and is higher in cells with intrinsically lower concentrations of tRNA Gln-CUG. The concentration of tRNA Gln-CUG also differs among different brain areas in the mouse. We propose that translational frameshifting may act as a significant disease modifier that contributes to the cell-selective neurotoxicity and disease course heterogeneity of HD on both cellular and individual levels.
Habitat fragmentation is one of the most important causes for the decline of plant species. However, plants differing in phylogeny, habitat requirements and biology are likely to respond differently to habitat fragmentation. We ask whether case studies on the effects of habitat fragmentation conducted so far allow generalizations about its effects on the fitness and genetic diversity of populations of endangered plant species. We compared the characteristics of plant species endangered in Germany whose sensitivity to habitat fragmentation had been studied with those of the endangered species that had not been studied. We found strong discrepancies between the two groups with regard to their taxonomy and traits relevant to their sensitivity to habitat fragmentation. Monocots, graminoids, clonal, abiotically pollinated and self compatible species were underrepresented among the studied species, and most study species were from a few habitat types, in particular grasslands. We conclude that our current knowledge of the effects of habitat fragmentation on plant populations is not sufficient to provide widely applicable guidelines for species management. The selection of species studied so far has been biased toward species from certain habitats and species exhibiting traits that probably make them vulnerable to habitat fragmentation. Future studies should include community-wide approaches in different habitats, e.g. re-visitation studies in which the species pool is assessed at different time intervals, and population-biological studies of species from a wide range of habitats, and of different life forms and growth strategies. A more representative picture of the effects of habitat fragmentation would allow a better assessment of threats and more specific recommendations for optimally managing populations of endangered plants.
The Tuz Golu Basin is the largest sedimentary depression located at the center of the Central Anatolian Plateau, an extensive, low-relief region with elevations of ca. 1 km located between the Pontide and Tauride mountains. Presently, the basin morphology and sedimentation processes are mainly controlled by the extensional Tuz Golu Fault Zone in the east and the transtensional Inonu-Eskisehir Fault System in the west. The purpose of this study is to contribute to the understanding of the Plio-Quaternary deformation history and to refine the timing of the latest extensional phase of the Tuz Golu Basin. Field observations, kinematic analyses, interpretations of seismic reflection lines, and Ar-40/Ar-39 dating of a key ignimbrite layer suggest that a regional phase of NNW-SSE to NE-SW contraction ended by 6.81 +/- 0.24 Ma and was followed by N-S to NE-SW extension during the Pliocene-Quaternary periods. Based on sedimentological and chronostratigraphic markers, the average vertical displacement rates over the past 5 or 3 Ma with respect to the central part of Tuz Golu Lake are 0.03 to 0.05 mm/year for the fault system at the western flank of the basin and 0.08 to 0.13 mm/year at the eastern flank. Paleo-shorelines of the Tuz Golu Lake, vestiges of higher lake levels related to Quaternary climate change, are important strain markers and were formed during Last Glacial Maximum conditions as indicated by a radiocarbon age of 21.8 +/- 0.4 ka BP obtained from a stromatolitic crust. Geomorphic observations and deformed lacustrine shorelines suggest that the main strand of the Tuz Golu Fault Zone straddling the foothills of the Sereflikochisar-Aksaray range has not been active during the Holocene. Instead, deformation appears to have migrated towards the interior of the basin along an offshore fault that runs immediately west of Sereflikochisar Peninsula. This basinward migration of deformation is probably associated with various processes acting at the lithospheric scale, such as plateau uplift and/or microplate extrusion.
Many applications, such as intermittent data assimilation, lead to a recursive application of Bayesian inference within a Monte Carlo context. Popular data assimilation algorithms include sequential Monte Carlo methods and ensemble Kalman filters (EnKFs). These methods differ in the way Bayesian inference is implemented. Sequential Monte Carlo methods rely on importance sampling combined with a resampling step, while EnKFs utilize a linear transformation of Monte Carlo samples based on the classic Kalman filter. While EnKFs have proven to be quite robust even for small ensemble sizes, they are not consistent since their derivation relies on a linear regression ansatz. In this paper, we propose another transform method, which does not rely on any a priori assumptions on the underlying prior and posterior distributions. The new method is based on solving an optimal transportation problem for discrete random variables.
In this paper a change-point detection method is proposed by extending the singular spectrum transformation (SST) developed as one of the capabilities of singular spectrum analysis (SSA). The method uncovers change points related with trends and periodicities. The potential of the proposed method is demonstrated by analysing simple model time series including linear functions and sine functions as well as real world data (precipitation data in Kenya). A statistical test of the results is proposed based on a Monte Carlo simulation with surrogate methods. As a result, the successful estimation of change points as inherent properties in the representative time series of both trend and harmonics is shown. With regards to the application, we find change points in the precipitation data of Kenyan towns (Nakuru, Naivasha, Narok, and Kisumu) which coincide with the variability of the Indian Ocean Dipole (IOD) suggesting its impact of extreme climate in East Africa.
The spatial and temporal variability of a low-centred polygon on the eastern floodplain area of the lower Anabar River (72.070 degrees N, 113.921 degrees E; northern Yakutia, Siberia) has been investigated using a multi-method approach. The present-day vegetation in each square metre was analysed, revealing a community of Larix, shrubby Betula, and Salix on the polygon rim, a dominance of Carex and Andromeda polifolia in the rim-to-pond transition zone, and a predominantly monospecific Scorpidium scorpioides coverage within the pond. The total organic carbon (TOC) content, TOC/TN (total nitrogen) ratio, grain size, vascular plant macrofossils, moss remains, diatoms, and pollen were analysed for two vertical sections and a sediment core from a transect across the polygon. Radiocarbon dating indicates that the formation of the polygon started at least 1500 yr ago; the general positions of the pond and rim have not changed since that time. Two types of pond vegetation were identified, indicating two contrasting development stages of the polygon. The first was a well-established moss association, dominated by submerged or floating Scorpidium scorpioides and/or Drepanocladus spp. and overgrown by epiphytic diatoms such as Tabellaria flocculosa and Eunotia taxa. This stage coincides temporally with a period in which the polygon was only drained by lateral subsurface water flow, as indicated by mixed grain sizes. A different moss association occurred during times of repeated river flooding (indicated by homogeneous medium-grained sand that probably accumulated during the annual spring snowmelt), characterized by an abundance of Meesia triquetra and a dominance of benthic diatoms (e. g. Navicula vulpina), indicative of a relatively high pH and a high tolerance of disturbance. A comparison of the local polygon vegetation (inferred from moss and macrofossil spectra) with the regional vegetation (inferred from pollen spectra) indicated that the moss association with Scorpidium scorpioides became established during relatively favourable climatic conditions, while the association dominated by Meesia triquetra occurred during periods of harsh climatic conditions. Our study revealed a strong riverine influence (in addition to climatic influences) on polygon development and the type of peat accumulated.
The digital laser rangefinder GLM Professional (R) BOSCH 250 VF was tested as a modified preproduction model with regard to its applicability of quantifying humans' height. The aim of this investigation was to determine and evaluate the instrument's precision, as well as its manageability within anthropometric field studies. Data collected by the digital laser rangefinder did not show a significant difference to data of control by an anthropometer. Furthermore, more than 96% of the difference values are located within area of agreement. Nevertheless, the GLM Professional (R) is a highly sensitive instrument and mean SD within threefold data acquisition is twice as high as SD resulting from data collection by an anthropometer. However, due to the minimal percentage differences within data acquisition and compared to the standard method, the GLM Professional (R) is proved to be a reliable instrument and to be highly applicable for anthropometric field studies. Furthermore, due to its excellent manageability and compact size, the GLM Professional (R) shows a very good applicability even for less trained anthropometrists and thus ameliorates the possibilities of collecting reliable data within anthropometric field studies.
We demonstrate new fluorophore-labelled materials based on acrylamide and on oligo(ethylene glycol) (OEG) bearing thermoresponsive polymers for sensing purposes and investigate their thermally induced solubility transitions. It is found that the emission properties of the polarity-sensitive (solvatochromic) naphthalimide derivative attached to three different thermoresponsive polymers are highly specific to the exact chemical structure of the macromolecule. While the dye emits very weakly below the LCST when incorporated into poly(N-isopropylacrylamide) (pNIPAm) or into a polyacrylate backbone bearing only short OEG side chains, it is strongly emissive in polymethacrylates with longer OEG side chains. Heating of the aqueous solutions above their cloud point provokes an abrupt increase of the fluorescence intensity of the labelled pNIPAm, whereas the emission properties of the dye are rather unaffected as OEG-based polyacrylates and methacrylates undergo phase transition. Correlated with laser light scattering studies, these findings are ascribed to the different degrees of pre-aggregation of the chains at low temperatures and to the extent of dehydration that the phase transition evokes. It is concluded that although the temperature-triggered changes in the macroscopic absorption characteristics, related to large-scale alterations of the polymer chain conformation and aggregation, are well detectable and similar for these LCST-type polymers, the micro-environment provided to the dye within each polymer network differs substantially. Considering sensing applications, this finding is of great importance since the temperature-regulated fluorescence response of the polymer depends more on the macromolecular architecture than the type of reporter fluorophore.
Sugar-based molecules and polysaccharide biomass can be turned into porous functional carbonaceous products at comparably low temperatures of 400 degrees C under a nitrogen atmosphere in the presence of an ionic liquid (IL) or a poly(ionic liquid) (PIL). The IL and PIL act as "activation agents" with own structural contribution, and effectively promote the conversion and pore generation in the biomaterials even at a rather low doping ratio (7 wt%). In addition, this "induced carbonization" and pore forming phenomenon enables the preservation of the biotemplate shape to the highest extent and was employed to fabricate shaped porous carbonaceous materials from carbohydrate-based biotemplates, exemplified here with cellulose filter membranes, coffee filter paper and natural cotton. These carbonized hybrids exhibit comparably good mechanical properties, such as bendability of membranes or shape recovery of foams. Moreover, the nitrogen atoms incorporated in the final products from the IL/PIL precursors further improve the oxidation stability in the fire-retardant tests.
Magnetic field generation in a jet-sheath plasma via the kinetic Kelvin-Helmholtz instability
(2013)
We have investigated the generation of magnetic fields associated with velocity shear between an unmagnetized relativistic jet and an unmagnetized sheath plasma. We have examined the strong magnetic fields generated by kinetic shear (Kelvin-Helmholtz) instabilities. Compared to the previous studies using counter-streaming performed by Alves et al. (2012), the structure of the kinetic Kelvin-Helmholtz instability (KKHI) of our jet-sheath configuration is slightly different, even for the global evolution of the strong transverse magnetic field. In our simulations the major components of growing modes are the electric field E-z, perpendicular to the flow boundary, and the magnetic field B-y, transverse to the flow direction. After the B-y component is excited, an induced electric field E-x, parallel to the flow direction, becomes significant. However, other field components remain small. We find that the structure and growth rate of KKHI with mass ratios m(i)/m(e) = 1836 and m(i)/m(e) = 20 are similar. In our simulations in the nonlinear stage is not as clear as in counter-streaming cases. The growth rate for a mildly-relativistic jet case (gamma(j) = 1.5) is larger than for a relativistic jet case (gamma(j) = 15).
Sustainable land use in Mountain Regions under global change synthesis across scales and disciplines
(2013)
Mountain regions provide essential ecosystem goods and services (EGS) for both mountain dwellers and people living outside these areas. Global change endangers the capacity of mountain ecosystems to provide key services. The Mountland project focused on three case study regions in the Swiss Alps and aimed to propose land-use practices and alternative policy solutions to ensure the provision of key EGS under climate and land-use changes. We summarized and synthesized the results of the project and provide insights into the ecological, socioeconomic, and political processes relevant for analyzing global change impacts on a European mountain region. In Mountland, an integrative approach was applied, combining methods from economics and the political and natural sciences to analyze ecosystem functioning from a holistic human-environment system perspective. In general, surveys, experiments, and model results revealed that climate and socioeconomic changes are likely to increase the vulnerability of the EGS analyzed. We regard the following key characteristics of coupled human-environment systems as central to our case study areas in mountain regions: thresholds, heterogeneity, trade-offs, and feedback. Our results suggest that the institutional framework should be strengthened in a way that better addresses these characteristics, allowing for (1) more integrative approaches, (2) a more network-oriented management and steering of political processes that integrate local stakeholders, and (3) enhanced capacity building to decrease the identified vulnerability as central elements in the policy process. Further, to maintain and support the future provision of EGS in mountain regions, policy making should also focus on project-oriented, cross-sectoral policies and spatial planning as a coordination instrument for land use in general.
We consider diffusion processes with a spatially varying diffusivity giving rise to anomalous diffusion. Such heterogeneous diffusion processes are analysed for the cases of exponential, power-law, and logarithmic dependencies of the diffusion coefficient on the particle position. Combining analytical approaches with stochastic simulations, we show that the functional form of the space-dependent diffusion coefficient and the initial conditions of the diffusing particles are vital for their statistical and ergodic properties. In all three cases a weak ergodicity breaking between the time and ensemble averaged mean squared displacements is observed. We also demonstrate a population splitting of the time averaged traces into fast and slow diffusers for the case of exponential variation of the diffusivity as well as a particle trapping in the case of the logarithmic diffusivity. Our analysis is complemented by the quantitative study of the space coverage, the diffusive spreading of the probability density, as well as the survival probability.
A water soluble fluorescent polymer as a dual colour sensor for temperature and a specific protein
(2013)
We present two thermoresponsive water soluble copolymers prepared via free radical statistical copolymerization of N-isopropylacrylamide (NIPAm) and of oligo(ethylene glycol) methacrylates (OEGMAs), respectively, with a solvatochromic 7-(diethylamino)-3-carboxy-coumarin (DEAC)-functionalized monomer. In aqueous solutions, the NIPAm-based copolymer exhibits characteristic changes in its fluorescence profile in response to a change in solution temperature as well as to the presence of a specific protein, namely an anti-DEAC antibody. This polymer emits only weakly at low temperatures, but exhibits a marked fluorescence enhancement accompanied by a change in its emission colour when heated above its cloud point. Such drastic changes in the fluorescence and absorbance spectra are observed also upon injection of the anti-DEAC antibody, attributed to the specific binding of the antibody to DEAC moieties. Importantly, protein binding occurs exclusively when the polymer is in the well hydrated state below the cloud point, enabling a temperature control on the molecular recognition event. On the other hand, heating of the polymer-antibody complexes releases a fraction of the bound antibody. In the presence of the DEAC-functionalized monomer in this mixture, the released antibody competitively binds to the monomer and the antibody-free chains of the polymer undergo a more effective collapse and inter-aggregation. In contrast, the emission properties of the OEGMA-based analogous copolymer are rather insensitive to the thermally induced phase transition or to antibody binding. These opposite behaviours underline the need for a carefully tailored molecular design of responsive polymers aimed at specific applications, such as biosensing.
A rare example of in situ linker generation with the formation of soft porous Zn- and Co-MOFs (IFP-9 and -10, respectively) is reported. The flexible ethoxy groups of IFP-9 and -10 protrude into the 1D hexagonal channels. The gas-sorption behavior of both materials for H-2, CO2 and CH4 showed wide hysteretic isotherms, typical for MOFs having a flexible substituent which can give rise to a gate effect.
Control of fixation duration during scene viewing by interaction of foveal and peripheral processing
(2013)
Processing in our visual system is functionally segregated, with the fovea specialized in processing fine detail (high spatial frequencies) for object identification, and the periphery in processing coarse information (low frequencies) for spatial orienting and saccade target selection. Here we investigate the consequences of this functional segregation for the control of fixation durations during scene viewing. Using gaze-contingent displays, we applied high-pass or low-pass filters to either the central or the peripheral visual field and compared eye-movement patterns with an unfiltered control condition. In contrast with predictions from functional segregation, fixation durations were unaffected when the critical information for vision was strongly attenuated (foveal low-pass and peripheral high-pass filtering); fixation durations increased, however, when useful information was left mostly intact by the filter (foveal high-pass and peripheral low-pass filtering). These patterns of results are difficult to explain under the assumption that fixation durations are controlled by foveal processing difficulty. As an alternative explanation, we developed the hypothesis that the interaction of foveal and peripheral processing controls fixation duration. To investigate the viability of this explanation, we implemented a computational model with two compartments, approximating spatial aspects of processing by foveal and peripheral activations that change according to a small set of dynamical rules. The model reproduced distributions of fixation durations from all experimental conditions by variation of few parameters that were affected by specific filtering conditions.
Whenever eye movements are measured, a central part of the analysis has to do with where subjects fixate and why they fixated where they fixated. To a first approximation, a set of fixations can be viewed as a set of points in space; this implies that fixations are spatial data and that the analysis of fixation locations can be beneficially thought of as a spatial statistics problem. We argue that thinking of fixation locations as arising from point processes is a very fruitful framework for eye-movement data, helping turn qualitative questions into quantitative ones. We provide a tutorial introduction to some of the main ideas of the field of spatial statistics, focusing especially on spatial Poisson processes. We show how point processes help relate image properties to fixation locations. In particular we show how point processes naturally express the idea that image features' predictability for fixations may vary from one image to another. We review other methods of analysis used in the literature, show how they relate to point process theory, and argue that thinking in terms of point processes substantially extends the range of analyses that can be performed and clarify their interpretation.
Intracellular photoactivation of caged cGMP induces myosin II and actin responses in motile cells
(2013)
Cyclic GMP (cGMP) is a ubiquitous second messenger in eukaryotic cells. It is assumed to regulate the association of myosin II with the cytoskeleton of motile cells. When cells of the social amoeba Dictyostelium discoideum are exposed to chemoattractants or to increased osmotic stress, intracellular cGMP levels rise, preceding the accumulation of myosin II in the cell cortex. To directly investigate the impact of intracellular cGMP on cytoskeletal dynamics in a living cell, we released cGMP inside the cell by laser-induced photo-cleavage of a caged precursor. With this approach, we could directly show in a live cell experiment that an increase in intracellular cGMP indeed induces myosin II to accumulate in the cortex. Unexpectedly, we observed for the first time that also the amount of filamentous actin in the cell cortex increases upon a rise in the cGMP concentration, independently of cAMP receptor activation and signaling. We discuss our results in the light of recent work on the cGMP signaling pathway and suggest possible links between cGMP signaling and the actin system.
Due to limited public budgets and the need to economize, the analysis of costs of hazard mitigation and emergency management of natural hazards becomes increasingly important for public natural hazard and risk management. In recent years there has been a growing body of literature on the estimation of losses which supported to help to determine benefits of measures in terms of prevented losses. On the contrary, the costs of mitigation are hardly addressed. This paper thus aims to shed some light on expenses for mitigation and emergency services. For this, we analysed the annual costs of mitigation efforts in four regions/countries of the Alpine Arc: Bavaria (Germany), Tyrol (Austria), South Tyrol (Italy) and Switzerland. On the basis of PPP values (purchasing power parities), annual expenses on public safety ranged from EUR 44 per capita in the Free State of Bavaria to EUR 216 in the Autonomous Province of South Tyrol. To analyse the (variable) costs for emergency services in case of an event, we used detailed data from the 2005 floods in the Federal State of Tyrol (Austria) as well as aggregated data from the 2002 floods in Germany. The analysis revealed that multi-hazards, the occurrence and intermixture of different natural hazard processes, contribute to increasing emergency costs. Based on these findings, research gaps and recommendations for costing Alpine natural hazards are discussed.
Flood loss modeling is an important component within flood risk assessments. Traditionally, stage-damage functions are used for the estimation of direct monetary damage to buildings. Although it is known that such functions are governed by large uncertainties, they are commonly applied - even in different geographical regions - without further validation, mainly due to the lack of real damage data. Until now, little research has been done to investigate the applicability and transferability of such damage models to other regions. In this study, the last severe flood event in the Austrian Lech Valley in 2005 was simulated to test the performance of various damage functions from different geographical regions in Central Europe for the residential sector. In addition to common stage-damage curves, new functions were derived from empirical flood loss data collected in the aftermath of recent flood events in neighboring Germany. Furthermore, a multi-parameter flood loss model for the residential sector was adapted to the study area and also evaluated with official damage data. The analysis reveals that flood loss functions derived from related and more similar regions perform considerably better than those from more heterogeneous data sets of different regions and flood events. While former loss functions estimate the observed damage well, the latter overestimate the reported loss clearly. To illustrate the effect of model choice on the resulting uncertainty of damage estimates, the current flood risk for residential areas was calculated. In the case of extreme events like the 300 yr flood, for example, the range of losses to residential buildings between the highest and the lowest estimates amounts to a factor of 18, in contrast to properly validated models with a factor of 2.3. Even if the risk analysis is only performed for residential areas, our results reveal evidently that a carefree model transfer in other geographical regions might be critical. Therefore, we conclude that loss models should at least be selected or derived from related regions with similar flood and building characteristics, as far as no model validation is possible. To further increase the general reliability of flood loss assessment in the future, more loss data and more comprehensive loss data for model development and validation are needed.
Background/Aims: Carbon monoxide (CO) interferes with cytochrome-dependent cellular functions and acts as gaseous transmitter. CO is released from CO-releasing molecules (CORM) including tricarbonyl-dichlororuthenium (II) dimer (CORM-2), molecules considered for the treatment of several disorders including vascular dysfunction, inflammation, tissue ischemia and organ rejection. Cytochrome P450-sensitive function include formation of 1,25-dihydroxyvitamin D-3 (1,25(OH)(2)D-3) by renal 25-hydroxyvitamin D-3 1-alpha-hydroxylase (Cyp27b1). The enzyme is regulated by PTH, FGF23 and klotho. 1,25(OH)(2)D-3 regulates Ca2+ and phosphate transport as well as klotho expression. The present study explored, whether CORM-2 influences 1,25(OH)(2)D-3 formation and klotho expression. Methods: Mice were treated with intravenous CORM-2 (20 mg/kg body weight). Plasma 1,25(OH)(2)D-3 and FGF23 concentrations were determined by ELISA, phosphate, calcium and creatinine concentrations by colorimetric methods, transcript levels by quantitative RT-PCR and protein expression by western blotting. Fgf23 mRNA transcript levels were further determined in rat osteosarcoma UMR106 cells without or with prior treatment for 24 hours with 20 mu M CORM-2. Results: CORM-2 injection within 24 hours significantly increased FGF23 plasma levels and decreased 1,25(OH)(2)D-3 plasma levels, renal Cyp27b1 gene expression as well as renal klotho protein abundance and transcript levels. Moreover, treatment of UMR106 cells with CORM-2 significantly increased Fgf23 transcript levels. Conclusion: CO-releasing molecule CORM-2 enhances FGF23 expression and release and decreases klotho expression and 1,25(OH)(2)D-3 synthesis.
Background: The biological properties of oxidized and non-oxidized PTH are substantially different. Oxidized PTH (oxPTH) loses its PTH receptor-stimulating properties, whereas non-oxidized PTH (n-oxPTH) is a full agonist of the receptor. This was described in more than 20 well published studies in the 1970(s) and 80(s). However, PTH oxidation has been ignored during the development of PTH assays for clinical use so far. Even the nowadays used third generation assay systems do not consider oxidation of PTH. We recently developed an assay to differentiate between oxPTH and n-oxPTH. In the current study we established normal values for this assay system. Furthermore, we compare the ratio of oxPTH to n-oxPTH in different population with chronic renal failure: 620 children with renal failure stage 2-4 of the 4C study, 342 adult patients on dialysis, and 602 kidney transplant recipients. In addition, we performed modeling of the interaction of either oxPTH or n-oxPTH with the PTH receptor using biophysical structure approaches. Results: The children had the highest mean as well as maximum n-oxPTH concentrations as compared to adult patients (both patients on dialysis as well as kidney transplant recipients). The relationship between oxPTH and n-oxPTH of individual patients varied substantially in all three populations with renal impairment. The analysis of n-oxPTH in 89 healthy control subjects revealed that n-oxPTH concentrations in patient with renal failure were higher as compared to healthy adult controls (2.25-fold in children with renal failure, 1.53-fold in adult patients on dialysis, and 1.56-fold in kidney transplant recipients, respectively). Computer assisted biophysical structure modeling demonstrated, however, minor sterical- and/or electrostatic changes in oxPTH and n-oxPTH. This indicated that PTH oxidation may induce refolding of PTH and hence alters PTH-PTH receptor interaction via oxidation induced three-dimensional structure alteration of PTH. Conclusion: A huge proportion of circulating PTH measured by current state-of-the-art assay systems is oxidized and thus not biologically active. The relationship between oxPTH and n-oxPTH of individual patients varied substantially. Non-oxidized PTH concentrations are 1.5 - 2.25 fold higher in patients with renal failure as compared to health controls. Measurements of n-oxPTH may reflect the hormone status more precise. The iPTH measures describes most likely oxidative stress in patients with renal failure rather than the PTH hormone status. This, however, needs to be demonstrated in further clinical studies.
Eye-movement research on implicit prosody has found effects of lexical stress on syntactic ambiguity resolution, suggesting that metrical well-formedness constraints interact with syntactic category assignment. Building on these findings, the present eyetracking study investigates whether contextual bias can modulate the effects of metrical structure on syntactic ambiguity resolution in silent reading. Contextual bias and potential stress-clash in the ambiguous region were crossed in a 2 x 2 design. Participants read biased context sentences followed by temporarily ambiguous test sentences. In the three-word ambiguous region, main effects of lexical stress were dominant, while early effects of context were absent. Potential stress clash yielded a significant increase in first-pass regressions and re-reading probability across the three words. In the disambiguating region, the disambiguating word itself showed increased processing difficulty (lower skipping and increased re-reading probability) when the disambiguation engendered a stress clash configuration, while the word immediately following showed main effects of context in those same measures. Taken together, effects of lexical stress upon eye movements were swift and pervasive across first-pass and second-pass measures, while effects of context were relatively delayed. These results indicate a strong role for implicit meter in guiding parsing, one that appears insensitive to higher-level constraints. Our findings are problematic for two classes of models, the two-stage garden-path model and the constraint-based competition-integration model, but can be explained by a variation on the two-stage model, the unrestricted race model.
Sightseeing in the poorest quarters of southern hemisphere cities has been observed occurring in Cape Town, Rio de Janeiro, Mumbai and many other cities. The increasing global interest in touring poor urban environments is accompanied by a strong morally charged debate; so far, this debate has not been critically addressed. This article avoids asking if slum tourism is good or bad, but instead seeks a second-order observation, i.e. to investigate under what conditions the social praxis of slum tourism is considered as good or bad, by processing information on esteem or dis-esteem among tourists and tour providers. Special attention is given to any relation between morality and place, and the thesis posited is that the moral charging of slum tourism is dependent on the presence of specific preconceived notions of slums and poverty. This shall be clarified by means of references to two empirical case studies carried out in (1) Cape Town in 2007 and 2008 and (2) Mumbai in 2009.
BACKGROUND: Mirror therapy (MT) was found to improve motor function after stroke, but its neural mechanisms remain unclear, especially in single stroke patients.
OBJECTIVES: The following imaging study was designed to compare brain activation patterns evoked by the mirror illusion in single stroke patients with normal subjects.
METHODS: Fifteen normal volunteers and five stroke patients with severe arm paresis were recruited. Cerebral activations during movement mirroring by means of a video chain were recorded with functional magnetic resonance imaging (fMRI). Single-subject analysis was performed using SPM 8.
RESULTS: For normal subjects, ten and thirteen subjects displayed lateralized cerebral activations evoked by the mirror illusion while moving their right and left hand respectively. The magnitude of this effect in the precuneus contralateral to the seen hand was not dependent on movement speed or subjective experience. Negative correlation of activation strength with age was found for the right hand only. The activation pattern in stroke patients is comparable to that of normal subjects and present in four out of five patients.
CONCLUSIONS: In summary, the mirror illusion can elicit cerebral activation contralateral to the perceived hand in the majority of single normal subjects, but not in all of them. This is similar even in stroke patients with severe hemiparesis.
Changes in rainfall interception along a secondary forest succession gradient in lowland Panama
(2013)
Secondary forests are rapidly expanding in tropical regions. Yet, despite the importance of understanding the hydrological consequences of land-cover dynamics, the relationship between forest succession and canopy interception is poorly understood. This lack of knowledge is unfortunate because rainfall interception plays an important role in regional water cycles and needs to be quantified for many modeling purposes. To help close this knowledge gap, we designed a throughfall monitoring study along a secondary succession gradient in a tropical forest region of Panama. The investigated gradient comprised 20 forest patches 3 to 130 yr old. We sampled each patch with a minimum of 20 funnel-type throughfall collectors over a continuous 2month period that had nearly 900 mm of rain. During the same period, we acquired forest inventory data and derived several forest structural attributes. We then applied simple and multiple regression models (Bayesian model averaging, BMA) and identified those vegetation parameters that had the strongest influence on the variation of canopy interception. Our analyses yielded three main findings. First, canopy interception changed rapidly during forest succession. After only a decade, throughfall volumes approached levels that are typical for mature forests. Second, a parsimonious (simple linear regression) model based on the ratio of the basal area of small stems to the total basal area outperformed more complex multivariate models (BMA approach). Third, based on complementary forest inventory data, we show that the influence of young secondary forests on interception in realworld fragmented landscapes might be detectable only in regions with a substantial fraction of young forests. Our re-sults suggest that where entire catchments undergo forest regrowth, initial stages of succession may be associated with a substantial decrease of streamflow generation. Our results further highlight the need to study hydrological processes in all forest succession stages, including early ones.
The dynamics of external contributions to the geomagnetic field is investigated by applying time-frequency methods to magnetic observatory data. Fractal models and multiscale analysis enable obtaining maximum quantitative information related to the short-term dynamics of the geomagnetic field activity. The stochastic properties of the horizontal component of the transient external field are determined by searching for scaling laws in the power spectra. The spectrum fits a power law with a scaling exponent beta, a typical characteristic of self-affine time-series. Local variations in the power-law exponent are investigated by applying wavelet analysis to the same time-series. These analyses highlight the self-affine properties of geomagnetic perturbations and their persistence. Moreover, they show that the main phases of sudden storm disturbances are uniquely characterized by a scaling exponent varying between 1 and 3, possibly related to the energy contained in the external field. These new findings suggest the existence of a long-range dependence, the scaling exponent being an efficient indicator of geomagnetic activity and singularity detection. These results show that by using magnetogram regularity to reflect the magnetosphere activity, a theoretical analysis of the external geomagnetic field based on local power-law exponents is possible.
Background: Low birth weight (LBW) might be a risk factor for acquiring lower respiratory tract infections (LRTIs) associated with disease related complications in early childhood. HFMD, a frequent viral infection in southern China, is a leading cause of lower respiratory tract infections in children. We analyzed whether LBW is a risk factor for children with HFMD to develop lower respiratory tract infections.
Methods: A total of 298 children with HFMD, admitted to a hospital in Qingyuan city, Guangdong province, were recruited. Demographic data and clinical parameters such as serum glucose level and inflammatory markers including peripheral white blood cell count, serum C-reactive protein, and erythrocyte sedimentation rate were routinely collected on admission. Birth weight data were derived from birth records.
Results: Mean birth weight (BW) was 167 g lower in patients with HFMD and LRTIs as compared to patients with solely HFMD (p = 0.022) and the frequency of birth weight below the tenth percentile was significantly higher in patients with HFMD and LRTIs (p = 0.002).
Conclusions: The results of the study show that low birth weight is associated with a higher incidence of lower respiratory tract infections in young children with HFMD.
Quantifying the association of plant functional traits to environmental gradients is a promising approach for understanding and projecting community responses to land use and climatic changes. Although habitat fragmentation and climate are expected to affect plant communities interactively, there is a lack of empirical studies addressing trait associations to fragmentation in different climatic regimes.
In this study, we analyse data on the key functional traits: specific leaf area (SLA), plant height, seed mass and seed number. First, we assess the evidence for the community assembly mechanisms habitat filtering and competition at different spatial scales, using several null-models and a comprehensive set of community-level trait convergence and divergence indices. Second, we analyse the association of community-mean traits with patch area and connectivity along a south-north productivity gradient.
We found clear evidence for trait convergence due to habitat filtering. In contrast, the evidence for trait divergence due to competition fundamentally depended on the null-model used. When the null-model controlled for habitat filtering, there was only evidence for trait divergence at the smallest sampling scale (0.25 m x 0.25 m). All traits varied significantly along the S-N productivity gradient. While plant height and SLA were consistently associated with fragmentation, the association of seed mass and seed number with fragmentation changed along the S-N gradient.
Our findings indicate trait convergence due to drought stress in the arid sites and due to higher productivity in the mesic sites. The association of plant traits to fragmentation is likely driven by increased colonization ability in small and/or isolated patches (plant height, seed number) or increased persistence ability in isolated patches (seed mass).
Our study provides the first empirical test of trait associations with fragmentation along a productivity gradient. We conclude that it is crucial to study the interactive effects of different ecological drivers on plant functional traits.
The possibility of an impact of global warming on the Indian monsoon is of critical importance for the large population of this region. Future projections within the Coupled Model Intercomparison Project Phase 3 (CMIP-3) showed a wide range of trends with varying magnitude and sign across models. Here the Indian summer monsoon rainfall is evaluated in 20 CMIP-5 models for the period 1850 to 2100. In the new generation of climate models, a consistent increase in seasonal mean rainfall during the summer monsoon periods arises. All models simulate stronger seasonal mean rainfall in the future compared to the historic period under the strongest warming scenario RCP-8.5. Increase in seasonal mean rainfall is the largest for the RCP-8.5 scenario compared to other RCPs. Most of the models show a northward shift in monsoon circulation by the end of the 21st century compared to the historic period under the RCP-8.5 scenario. The interannual variability of the Indian monsoon rainfall also shows a consistent positive trend under unabated global warming. Since both the long-term increase in monsoon rainfall as well as the increase in interannual variability in the future is robust across a wide range of models, some confidence can be attributed to these projected trends.
Transcriptome analysis through next-generation sequencing technologies allows the generation of detailed gene catalogs for non-model species, at the cost of new challenges with regards to computational requirements and bioinformatics expertise. Here, we present TRAPID, an online tool for the fast and efficient processing of assembled RNA-Seq transcriptome data, developed to mitigate these challenges. TRAPID offers high-throughput open reading frame detection, frameshift correction and includes a functional, comparative and phylogenetic toolbox, making use of 175 reference proteomes. Benchmarking and comparison against state-of-the-art transcript analysis tools reveals the efficiency and unique features of the TRAPID system.
Polymers exhibiting cell-selective effects represent an extensive research field with high relevance for biomedical applications e.g. in the cardiovascular field supporting re-endothelialization while suppressing smooth muscle cell overgrowth. Such an endothelial cell-selective effect could be recently demonstrated for a copolyetheresterurethane (PDC) containing biodegradable poly(p-dioxanone) and poly(epsilon-caprolactone) segments, which selectively enhanced the adhesion of human umbilical vein endothelial cells (HUVEC) while suppressing the attachment of smooth muscle cells (SMC).
In this study we investigated the influence of the fibre orientation (random and aligned) and fibre diameter (2 mu m and 500 nm) of electrospun PDC scaffolds on the adhesion, proliferation and apoptosis of HUVEC and SMC.
Adhesion, viability and proliferation of HUVEC was diminished when the fibre diameter was reduced to a submicron scale, while the orientation of the microfibres did only slightly influence the cellular behaviour. In contrast, a submicron fibre diameter improved SMC viability. In conclusion, PDC scaffolds with micron-sized single fibres could be promising candidate materials for cell-selective stent coatings.
Invasive alien species pose a great threat to the integrity of natural communities by competition with and predation on native species. In Germany the invasive raccoon dog (Nyctereutes procyonoides) and the native red fox (Vulpes vulpes) occupy a similar ecological niche. Therefore, the aim of our study was to discover the extent of exploitative diet competition between these two generalist carnivores. Carcasses of red foxes (n=256) and raccoon dogs (n=253) were collected throughout Mecklenburg Western-Pomerania (north-east Germany) and stomachs contains were analysed. Frequency of occurrence and biomass share indicate that both canids are omnivorous and pursue opportunistic feeding strategies. Small mammals and edible plant material were the most important food resources for red foxes and raccoon dogs. Nonetheless, interspecies differences were recorded for edible plant material, small mammals and insects. While red foxes mostly feed on voles, raccoon dogs consumed mice and shrews as often as voles. Only raccoon dogs preyed on amphibians. There were no differences in carrion consumption, both species scavenged on wild boar and we found clear competition for carrion year-round. Moreover, there was evidence that two red foxes foraged on raccoon dogs and vice versa. The mean annual interspecies diet overlap index was relatively high. The diets determined for raccoon dogs and red foxes were quite similar and a similar food niche breadth was recorded. However, only minor competition is assumed to take place since differences in feeding habits do exist.
Tyrant flycatchers (Aves: Tyrannidae) are endemic to the New World, and many species of this group are threatened or near-threatened at the global level. The aim of this study was to test the 18 microsatellite markers that have been published for other Tyrant flycatchers in the Strange-tailed Tyrant (Alectrurus risora) and the Sharp-tailed Tyrant (Culicivora caudacuta), two endemic species of southern South American grasslands that are classified as vulnerable. We also analyzed the usefulness of loci in relation to phylogenetic distance to the source species. Amplification success was high in both species (77 to 83%) and did not differ between the more closely and more distantly related species to the source species. Polymorphism success was also similar for both species, with 9 and 8 loci being polymorphic, respectively. An increased phylogenetic distance thus does not gradually lead to allelic or locus dropouts, implying that in Tyrant flycatchers, the published loci are useful independent of species relatedness.
In this chapter, equipped with our previously obtained knowledge of exit and transition times in the limit of small noise amplitude ??0 , we shall investigate the global asymptotic behavior of our jump diffusion process in the time scale in which transitions occur, i.e. in the scale given by ?0(?)=?(1?Bc?(0)),?,?>0 . It turns out that in this time scale, the switching of the diffusion between neighborhoods of the stable solutions ? ± can be well described by a Markov chain jumping back and forth between two states with a characteristic Q-matrix determined by the quantities ?((D±0)c)?(Bc?(0)) as jumping rates.
Asymptotic transition times
(2013)
Asymptotic exit times
(2013)
In this preparatory chapter, the tools of stochastic analysis needed for the investigation of the asymptotic behavior of the stochastic Chafee-Infante equation are provided. In the first place, this encompasses a recollection of basic facts about Lévy processes with values in Hilbert spaces. Playing the role of the additive noise processes perturbing the deterministic Chafee-Infante equation in the systems the stochastic dynamics of which will be our main interest, symmetric ?-stable Lévy processes are in the focus of our investigation (Sect. 3.1).
In this chapter, we introduce the deterministic Chafee-Infante equation. This equation has been the subject of intense research and is very well understood now. We recall some properties of its longtime dynamics and in particular the structure of its attractor. We then define reduced domains of attraction that will be fundamental in our study and give a result describing precisely the time that a solution starting form a reduced domain of attraction needs to reach a stable equilibrium. This result is then proved using the detailed knowledge of the attractor and classical tools such as the stable and unstable manifolds in a neighborhood of an equilibrium.
Background/Aims: Cortisol plays an important role during pregnancy. It controls maternal glucose metabolism and fetal development. Cortisol metabolism is partially controlled by the 11b-HSD2. This enzyme is expressed in the kidney and human placenta. The activity of the enzyme is partially controlled by functional polymorphisms: the HSD11B2[CA]n microsatellite polymorphism. The impact of this functional gene polymorphism on cortisol metabolism and potential effects on the newborn's is unknown so far. Methods: In the current prospective birth cohort study in southern Asia, we analyzed the association of the HSD11B2[CA]n microsatellite polymorphisms in 187 mothers and their newborn's on maternal and newborn's serum cortisol concentrations. Results: Using multivariable regression analyses considering known confounding ( gestational age, newborn's gender, the labor uterine contraction states and the timing during the day of blood taking), we showed that the fetal HSD11B2[CA]n microsatellite polymorphisms in the first intron was related to maternal cortisol concentration ( R2=0.26, B=96.27, p=0.007), whereas as the newborn's cortisol concentrations were independent of fetal and maternal HSD11B2[CA] n microsatellite polymorphism. Conclusions: Our study showed for the first time that the fetal HSD11B2[CA]n microsatellite polymorphism of the HSD11B2 gene in healthy uncomplicated human pregnancy is associated with maternal cortisol concentration. This indicates that fetal genes controlling cortisol metabolism may affect maternal cortisol concentration and hence physiology in healthy pregnant women.
A new occurrence of eclogites was found in the Kesandere valley in the eastern most part of the Bitlis complex, SE Anatolia. These high-pressure (HP) relics were preserved in calc-arenitic metasediments within the high-grade metamorphic basement of the Bitlis complex. The eclogitic parageneses were strongly overprinted during decompression and heating. These new eclogites locality complements the evidence of blueschist-facies metamorphism documented recently in the meta-sedimentary cover sequence of this part of the Bitlis complex. Thermodynamic calculations suggest peak conditions of ca. 480-540 degrees C/1.9-2.4GPa. New U/Pb dates of 84.4 +/-.9 and 82.4 +/-.9Ma were obtained on zircons from two Kesandere eclogite samples. On the basis of geochemical criteria, these dates are interpreted to represent zircon crystallization during the eclogitic peak stage. Kesandere eclogites differ from those previously described in the western Bitlis complex (Mt. Gablor locality) in terms of lithologic association, protolithic origin, and peak P-T conditions (600-650 degrees C/1.0-2.0GPa, respectively). On the other hand, eclogitic metamorphism of Kesandere metasediments occurred shortly before blueschist-facies metamorphism of the sedimentary cover (79-74Ma Ar-40/Ar-39 white mica). Therefore, the exhumation of Kesandere eclogites started between ca. 82 and 79Ma, while the meta-sedimentary cover was being buried. During this short time span, Kesandere eclogite were likely uplifted from similar to 65 to 35km depth, indicating a syn-subduction exhumation rate of similar to 4.3mm/a. Subsequently, eclogite- and blueschist-facies rocks were likely retrogressed contemporarily during collision-type metamorphism (around 72-69Ma). The Bitlis HP rocks thus sample a subduction zone that separated the Bitlis-Puturge (Bistun?) block from the South-Armenian block, further north. To the south, Eocene metasediments of the Urse formation are imbricated below the Bitlis complex. They contain (post Eocene) blueschists, testifying separation from the Arabian plate and southward migration of the subduction zone. The HT overprint of Kesandere eclogites can be related to the asthenospheric flow provoked by subducting slab retreat or break off.
We know exactly what you want the development of a completely individualised conjoint analysis
(2013)
Improving the predictive validity of conjoint analysis has been an important research objective for many years. Whereas the majority of attempts have been different approaches to preference modelling, data collection or product presentation, only a few scholars have tried to improve predictive validity by individualising conjoint designs. This comes as a surprise because many markets have observed an augmented demand for customised products and highly heterogeneous customers' preferences. Against this background, the authors develop a conjoint variant based on a completely individualised conjoint design. More concretely, the new approach not only individualises the attributes, but also the attribute levels. The results of a comprehensive empirical study yield a significantly higher validity than existing standardised-level conjoint approaches. Consequently, they help marketers to gain deeper insights into their customers' preferences.
Temporal evolution of the re-breakdown voltage in small gaps from nanoseconds to milliseconds
(2013)
A detailed understanding of electric breakdown in dielectrics is of scientific and technological interest. In gaseous dielectrics, a so-called re-breakdown is sometimes observed after extinction of the previous discharge. Although time-dependent re-breakdown voltage is essentially known, its behavior immediately after the previous discharge is not precisely understood. We present an electronic circuit for accurate measurements of the time-dependent re-breakdown voltage in small gaps from tens of nanoseconds to several milliseconds after the previous spark. Results from such experiments are compared with earlier findings, and relevant physical mechanisms such as heating of the gas, decay of the plasma, and ionization of excited atoms and molecules are discussed. It is confirmed that the thermal model is not valid at times below several microseconds.
We study time averages of single particle trajectories in scale-free anomalous diffusion processes, in which the measurement starts at some time t(a) > 0 after initiation of the process at t = 0. Using aging renewal theory, we show that for such nonstationary processes a large class of observables are affected by a unique aging function, which is independent of boundary conditions or the external forces. Moreover, we discuss the implications of aging induced population splitting: with growing age ta of the process, an increasing fraction of particles remains motionless in a measurement of fixed duration. Consequences for single biomolecule tracking in live cells are discussed.
Human-mediated dispersal is known as an important driver of long-distance dispersal for plants but underlying mechanisms have rarely been assessed. Road corridors function as routes of secondary dispersal for many plant species but the extent to which vehicles support this process remains unclear. In this paper we quantify dispersal distances and seed deposition of plant species moved over the ground by the slipstream of passing cars. We exposed marked seeds of four species on a section of road and drove a car along the road at a speed of 48 km/h. By tracking seeds we quantified movement parallel as well as lateral to the road, resulting dispersal kernels, and the effect of repeated vehicle passes. Median distances travelled by seeds along the road were about eight meters for species with wind dispersal morphologies and one meter for species without such adaptations. Airflow created by the car lifted seeds and resulted in longitudinal dispersal. Single seeds reached our maximum measuring distance of 45 m and for some species exceeded distances under primary dispersal. Mathematical models were fit to dispersal kernels. The incremental effect of passing vehicles on longitudinal dispersal decreased with increasing number of passes as seeds accumulated at road verges. We conclude that dispersal by vehicle airflow facilitates seed movement along roads and accumulation of seeds in roadside habitats. Dispersal by vehicle airflow can aid the spread of plant species and thus has wide implications for roadside ecology, invasion biology and nature conservation.
We report on the detection of a very rapid TeV gamma-ray flare from BL Lacertae on 2011 June 28 with the Very Energetic Radiation Imaging Telescope Array System (VERITAS). The flaring activity was observed during a 34.6 minute exposure, when the integral flux above 200 GeV reached (3.4 +/- 0.6) x 10(-6) photons m(-2) s(-1), roughly 125% of the Crab Nebula flux measured by VERITAS. The light curve indicates that the observations missed the rising phase of the flare but covered a significant portion of the decaying phase. The exponential decay time was determined to be 13 +/- 4 minutes, making it one of the most rapid gamma-ray flares seen from a TeV blazar. The gamma-ray spectrum of BL Lacertae during the flare was soft, with a photon index of 3.6 +/- 0.4, which is in agreement with the measurement made previously by MAGIC in a lower flaring state. Contemporaneous radio observations of the source with the Very Long Baseline Array revealed the emergence of a new, superluminal component from the core around the time of the TeV gamma-ray flare, accompanied by changes in the optical polarization angle. Changes in flux also appear to have occurred at optical, UV, and GeV gamma-ray wavelengths at the time of the flare, although they are difficult to quantify precisely due to sparse coverage. A strong flare was seen at radio wavelengths roughly four months later, which might be related to the gamma-ray flaring activities. We discuss the implications of these multiwavelength results.
We study the ergodic properties of superdiffusive, spatiotemporally coupled Levy walk processes. For trajectories of finite duration, we reveal a distinct scatter of the scaling exponents of the time averaged mean squared displacement (delta x(2)) over bar around the ensemble value 3 - alpha (1 < alpha < 2) ranging from ballistic motion to subdiffusion, in strong contrast to the behavior of subdiffusive processes. In addition we find a significant dependence of the average of (delta x(2)) over bar over an ensemble of trajectories as a function of the finite measurement time. This so-called finite-time amplitude depression and the scatter of the scaling exponent is vital in the quantitative evaluation of superdiffusive processes. Comparing the long time average of the second moment with the ensemble mean squared displacement, these only differ by a constant factor, an ultraweak ergodicity breaking.
The wood mouse is a common and abundant species in agricultural landscape and is a focal species in pesticide risk assessment. Empirical studies on the ecology of the wood mouse have provided sufficient information for the species to be modelled mechanistically. An individual-based model was constructed to explicitly represent the locations and movement patterns of individual mice. This together with the schedule of pesticide application allows prediction of the risk to the population from pesticide exposure. The model included life-history traits of wood mice as well as typical landscape dynamics in agricultural farmland in the UK. The model obtains a good fit to the available population data and is fit for risk assessment purposes. It can help identify spatio-temporal situations with the largest potential risk of exposure and enables extrapolation from individual-level endpoints to population-level effects. Largest risk of exposure to pesticides was found when good crop growth in the "sink" fields coincided with high "source" population densities in the hedgerows.
In the oxidative system (t-BuOCl+NaI) trifluoromethanesulfonamide is regio- and stereoselectively added to only one double bond of cyclopentadiene and 1,3-cyclohexadiene giving rise to 1,1,1-trifluoro-N-(5-iodocyclopent-2-en-1-yl)methanesulfonamide 7 and trans-N,N'-cyclohex-3-en-1,2-diylbis(1,1,1-trifluoromethanesulfonamide) 8. The structure of 7 and 8 was determined by X-ray, NMR, and MS. With 1,4-cyclohexadiene, addition to both double bonds occurs with the formation of N,N'-(4-chloro-5-iodocyclohexan-1,2-diyl)bis(1,1,1-trifluoromethanesulfonamide) 9. Under the action of sodium iodide in acetone, the latter product undergoes halogenophilic attack with the reduction of the CHI group and elimination of HCl to give trans-N,N'-cyclohex-4-en-1,2-diylbis(1,1,1-trifluoromethanesulfonamide) 10, whose structure was also determined by X-ray analysis. 1,3,5-Cycloheptatriene under these conditions is oxidized to benzaldehyde and does not react with trifluoromethanesulfonamide.
Through their relevance for sediment budgets and the sensitivity of geomorphic systems, geomorphic coupling and (sediment) connectivity represent important topics in geomorphology. Since the introduction of the systems perspective to physical geography by Chorley and Kennedy (1971), a catchment has been perceived as consisting of landscape elements (e.g. landforms, subcatchments) that are coupled by geomorphic processes through sediment transport. In this study, we present a novel application of mathematical graph theory to explore the network structure of coarse sediment pathways in a central alpine catchment. Numerical simulation models for rockfall, debris flows, and (hillslope and channel) fluvial processes are used to establish a spatially explicit graph model of sediment sources, pathways and sinks. The raster cells of a digital elevation model form the nodes of this graph, and simulated sediment trajectories represent the corresponding edges. Model results are validated by visual comparison with the field situation and aerial photos. The interaction of sediment pathways, i.e. where the deposits of a geomorphic process form the sources of another process, forms sediment cascades, represented by paths (a succession of edges) in the graph model. We show how this graph can be used to explore upslope (contributing area) and downslope (source to sink) functional connectivity by analysing its nodes, edges and paths. The analysis of the spatial distribution, composition and frequency of sediment cascades yields information on the relative importance of geomorphic processes and their interaction (however regardless of their transport capacity). In the study area, the analysis stresses the importance of mass movements and their interaction, e.g. the linkage of large rockfall source areas to debris flows that potentially enter the channel network. Moreover, it is shown that only a small percentage of the study area is coupled to the channel network which itself is longitudinally disconnected by natural and anthropogenic barriers. Besides the case study, we discuss the methodological framework and alternatives for node and edge representations of graph models in geomorphology. We conclude that graph theory provides an excellent methodological framework for the analysis of geomorphic systems, especially for the exploration of quantitative approaches towards sediment connectivity.
Leaf wax n-alkanes of terrestrial plants are long-chain hydrocarbons that can persist in sedimentary records over geologic timescales. Since meteoric water is the primary source of hydrogen used in leaf wax synthesis, the hydrogen isotope composition (delta D value) of these biomarkers contains information on hydrological processes. Consequently, leaf wax n-alkane delta D values have been advocated as powerful tools for paleohydrological research. The exact kind of hydrological information that is recorded in leaf wax n-alkanes remains, however, unclear because critical processes that determine their delta D values have not yet been resolved. In particular the effects of evaporative deuterium (D)-enrichment of leaf water on the delta D values of leaf wax n-alkanes have not yet been directly assessed and quantified. Here we present the results of a study where we experimentally tested if and by what magnitude evaporative D-enrichment of leaf water affects the delta D of leaf wax n-alkanes in angiosperm C3 and C4 plants. Our study revealed that n-alkane delta D values of all plants that we investigated were affected by evaporative D-enrichment of leaf water. For dicotyledonous plants we found that the full extent of leaf water evaporative D-enrichment is recorded in leaf wax n-alkane delta D values. For monocotyledonous plants we found that between 18% and 68% of the D-enrichment in leaf water was recorded in the delta D values of their n-alkanes. We hypothesize that the different magnitudes by which evaporative D-enrichment of leaf water affects the delta D values of leaf wax n-alkanes in monocotyledonous and dicotyledonous plants is the result of differences in leaf growth and development between these plant groups. Our finding that the evaporative D-enrichment of leaf water affects the delta D values of leaf wax n-alkanes in monocotyledonous and dicotyledonous plants albeit at different magnitudes - has important implications for the interpretation of leaf wax n-alkane delta D values from paleohydrological records. In addition, our finding opens the door to employ delta D values of leaf wax n-alkanes as new ecohydrological proxies for evapotranspiration that can be applied in contemporary plant and ecosystem research.
A new sulfonated aniline-modified poly(vinyl alcohol)/K-feldspar (SAPK) composite was prepared. The cation-exchange capacity of the composite was found to be S times that of neat feldspar. The specific surface area and point of zero charge also changed significantly upon modification, from 15.6 +/- 0.1 m(2)/g and 2.20 (K-feldspar) to 73.6 +/- 0.3 m(2)/g and 1.91 (SAPK). Zn2+, Cd2+, and Pb2+ adsorption was found to be largely independent of pH, and the metal adsorption rate on SAPK was higher than that on neat feldspar. This particularly applies to the initial adsorption rates. The adsorption process involves both film and pore diffusion; film diffusion initially controls the adsorption. The Freundlich and Langmuir models were found to fit metal-ion adsorption on SAPK most accurately. Adsorption on neat feldspar was best fitted with a Langmuir model, indicating the formation of adsorbate monolayers. Both pure feldspar and SAPK showed better selectivity for Pb2+ than for Cd2+ or Zn2+.
To address the nature of charge transport and the origin of severe (intrinsic) trapping in electron-transporting polymers, transient and steady-state charge transport measurements have been conducted on the prototype donor/acceptor copolymer poly[2,7-(9,9-dialkyl-fluorene)-alt-5,5-(4',7'-di-2-thienyl-2',1',3'-benzothiadiazole)] (PFTBTT). A charge-generation layer technique is used to selectively address transport of the desired charge carrier type, to perform time-of-flight measurements on samples with < 200 nm thickness, and to combine the time-of-flight and the photocharge extraction by linearly increasing voltage (photo-CELIV) techniques to investigate charge carrier dynamics over a wide time range. Significant trapping of free electrons is observed in the bulk of dioctyl-substituted PFTBTT (alt-PF8TBTT), introducing a strong relaxation of the charge carrier mobility with time. We used Monte-Carlo simulation to simulate the measured transient data and found that all measurements can be modeled with a single parameter set, with the charge transport behavior determined by multiple trapping and detrapping of electrons in an exponential trap distribution. The influence of the concomitant mobility relaxation on the transient photocurrent characteristics in photo-CELIV experiments is discussed and shown to explain subtle features that were seen in former publications but were not yet assigned to electron trapping. Comparable studies on PFTBTT copolymers with chemical modifications of the side chains and backbone suggest that the observed electron trapping is not caused by a distinct chemical species but rather is related to interchain interactions.
Under dilute in vitro conditions transcription factors rapidly locate their target sequence on DNA by using the facilitated diffusion mechanism. However, whether this strategy of alternating between three-dimensional bulk diffusion and one-dimensional sliding along the DNA contour is still beneficial in the crowded interior of cells is highly disputed. Here we use a simple model for the bacterial genome inside the cell and present a semi-analytical model for the in vivo target search of transcription factors within the facilitated diffusion framework. Without having to resort to extensive simulations we determine the mean search time of a lac repressor in a living E. coli cell by including parameters deduced from experimental measurements. The results agree very well with experimental findings, and thus the facilitated diffusion picture emerges as a quantitative approach to gene regulation in living bacteria cells. Furthermore we see that the search time is not very sensitive to the parameters characterizing the DNA configuration and that the cell seems to operate very close to optimal conditions for target localization. Local searches as implied by the colocalization mechanism are only found to mildly accelerate the mean search time within our model.
Novel hydrogels based on hydroxyethyl starch modified with polyethylene glycol methacrylate (HES-P(EG)(6)MA) were developed as delivery system for the controlled release of proteins. Since the drug release behavior is supposed to be related to the pore structure of the hydrogel network the pore sizes were determined by cryo-SEM, which is a mild technique for imaging on a nanometer scale. The results showed a decreasing pore size and an increase in pore homogeneity with increasing polymer concentration. Furthermore, the mesh sizes of the hydrogels were calculated based on swelling data. Pore and mesh size were significantly different which indicates that both structures are present in the hydrogel. The resulting structural model was correlated with release data for bulk hydrogel cylinders loaded with FITC-dextran and hydrogel microspheres loaded with FITC-IgG and FITC-dextran of different molecular size. The initial release depended much on the relation between hydrodynamic diameter and pore size while the long term release of the incorporated substances was predominantly controlled by degradation of the network of the much smaller meshes.
Robustness of biochemical systems has become one of the central questions in systems biology although it is notoriously difficult to formally capture its multifaceted nature. Maintenance of normal system function depends not only on the stoichiometry of the underlying interrelated components, but also on the multitude of kinetic parameters. Invariant flux ratios, obtained within flux coupling analysis, as well as invariant complex ratios, derived within chemical reaction network theory, can characterize robust properties of a system at steady state. However, the existing formalisms for the description of these invariants do not provide full characterization as they either only focus on the flux-centric or the concentration-centric view. Here we develop a novel mathematical framework which combines both views and thereby overcomes the limitations of the classical methodologies. Our unified framework will be helpful in analyzing biologically important system properties.
Matrix product states and their continuous analogues are variational classes of states that capture quantum many-body systems or quantum fields with low entanglement; they are at the basis of the density-matrix renormalization group method and continuous variants thereof. In this work we show that, generically, N-point functions of arbitrary operators in discrete and continuous translation invariant matrix product states are completely characterized by the corresponding two- and three-point functions. Aside from having important consequences for the structure of correlations in quantum states with low entanglement, this result provides a new way of reconstructing unknown states from correlation measurements, e. g., for one-dimensional continuous systems of cold atoms. We argue that such a relation of correlation functions may help in devising perturbative approaches to interacting theories.
Gamma-ray line signatures can be expected in the very-high-energy (E-gamma > 100 GeV) domain due to self-annihilation or decay of dark matter (DM) particles in space. Such a signal would be readily distinguishable from astrophysical gamma-ray sources that in most cases produce continuous spectra that span over several orders of magnitude in energy. Using data collected with the H. E. S. S. gamma-ray instrument, upper limits on linelike emission are obtained in the energy range between similar to 500 GeV and similar to 25 TeV for the central part of the Milky Way halo and for extragalactic observations, complementing recent limits obtained with the Fermi-LAT instrument at lower energies. No statistically significant signal could be found. For monochromatic gamma-ray line emission, flux limits of (2 x 10(-7)-2 x 10(-5)) m(-2)s(-1)sr(-1) and (1 x 10(-8)- 2 x 10(-6)) m(-2)s(-1)sr(-1) are obtained for the central part of the Milky Way halo and extragalactic observations, respectively. For a DM particle mass of 1 TeV, limits on the velocity- averaged DM annihilation cross section <sigma upsilon >(chi chi ->gamma gamma) reach similar to 10(-27)cm(3)s(-1), based on the Einasto parametrization of the Galactic DM halo density profile. DOI: 10.1103/PhysRevLett.110.041301
Six-color time-resolved forster resonance energy transfer for ultrasensitive multiplexed biosensing
(2013)
Simultaneous monitoring of multiple molecular interactions and multiplexed detection of several diagnostic biomarkers at very low concentrations have become important issues in advanced biological and chemical sensing. Here we present an optically multiplexed six-color Forster resonance energy transfer (FRET) biosensor for simultaneous monitoring of five different individual binding events. We combined simultaneous FRET from one Tb complex to five different organic dyes measured in a filter-based time-resolved detection format with a sophisticated spectral crosstalk correction, which results in very efficient background suppression. The advantages and robustness of the multiplexed FRET sensor were exemplified by analyzing a 15-component lung cancer immunoassay involving 10 different antibodies and five different tumor markers in a single 50 mu L human serum sample. The multiplexed biosensor offers clinically relevant detection limits in the low picomolar (ng/mL) concentration range for all five markers, thus providing an effective early screening tool for lung cancer with the possibility of distinguishing small-cell from non-small-cell lung carcinoma. This novel technology will open new doors for multiple biomarker diagnostics as well as multiplexed real-time imaging and spectroscopy.
Evidence for an approximate analog system of numbers has been provided by the finding that the comparison of two numerals takes longer and is more error-prone if the semantic distance between the numbers becomes smaller (so-called numerical distance effect). Recent embodied theories suggest that analog number representations are based on previous sensory experiences and constitute therefore a common magnitude metric shared by multiple domains. Here we demonstrate the existence of a cross-modal semantic distance effect between symbolic and tactile numerosities. Participants received tactile stimulations of different amounts of fingers while reading Arabic digits and indicated verbally whether the amount of stimulated fingers was different from the simultaneously presented digit or not. The larger the semantic distance was between the two numerosities, the faster and more accurate participants made their judgments. This cross-modal numerosity distance effect suggests a direct connection between tactile sensations and the concept of numerical magnitude. A second experiment replicated the interaction between symbolic and tactile numerosities and showed that this effect is not modulated by the participants' finger counting habits. Taken together, our data provide novel evidence for a shared metric for symbolic and tactile numerosities as an instance of an embodied representation of numbers.
Management of data to produce scientific knowledge is a key challenge for biological research in the 21st century. Emerging high-throughput technologies allow life science researchers to produce big data at speeds and in amounts that were unthinkable just a few years ago. This places high demands on all aspects of the workflow: from data capture (including the experimental constraints of the experiment), analysis and preservation, to peer-reviewed publication of results. Failure to recognise the issues at each level can lead to serious conflicts and mistakes; research may then be compromised as a result of the publication of non-coherent protocols, or the misinterpretation of published data. In this report, we present the results from a workshop that was organised to create an ontological data-modelling framework for Laboratory Protocol Standards for the Molecular Methods Database (MolMeth). The workshop provided a set of short- and long-term goals for the MolMeth database, the most important being the decision to use the established EXACT description of biomedical ontologies as a starting point.
Block copolymer elastomer conductors (BEC) are mixtures of block copolymers grafted with conducting polymers, which are found to support very large strains, while retaining a high level of conductivity. These novel materials may find use in stretchable electronics. The use of BEC is demonstrated in a capacitive strain sensor and in an artificial muscle of the dielectric elastomer actuator type, supporting more than 100% actuation strain and capacity strain sensitivity up to 300%.
The Acheulean technological tradition, characterized by a large (>10 cm) flake-based component, represents a significant technological advance over the Oldowan. Although stone tool assemblages attributed to the Acheulean have been reported from as early as circa 1.6-1.75 Ma, the characteristics of these earliest occurrences and comparisons with later assemblages have not been reported in detail. Here, we provide a newly established chronometric calibration for the Acheulean assemblages of the Konso Formation, southern Ethiopia, which span the time period similar to 1.75 to <1.0 Ma. The earliest Konso Acheulean is chronologically indistinguishable from the assemblage recently published as the world's earliest with an age of similar to 1.75 Ma at Kokiselei, west of Lake Turkana, Kenya. This Konso assemblage is characterized by a combination of large picks and crude bifaces/unifaces made predominantly on large flake blanks. An increase in the number of flake scars was observed within the Konso Formation handaxe assemblages through time, but this was less so with picks. The Konso evidence suggests that both picks and handaxes were essential components of the Acheulean from its initial stages and that the two probably differed in function. The temporal refinement seen, especially in the handaxe forms at Konso, implies enhanced function through time, perhaps in processing carcasses with long and stable cutting edges. The documentation of the earliest Acheulean at similar to 1.75 Ma in both northern Kenya and southern Ethiopia suggests that behavioral novelties were being established in a regional scale at that time, paralleling the emergence of Homo erectus-like hominid morphology.
We present a novel method for performing quantum state tomography for many-particle systems, which are particularly suitable for estimating the states in lattice systems such as of ultra-cold atoms in optical lattices. We show that the need to measure a tomographically complete set of observables can be overcome by letting the state evolve under some suitably chosen random circuits followed by the measurement of a single observable. We generalize known results about the approximation of unitary two-designs, i.e. certain classes of random unitary matrices, by random quantum circuits and connect our findings to the theory of quantum compressed sensing. We show that for ultra-cold atoms in optical lattices established experimental techniques such as optical super-lattices, laser speckles and time-of-flight measurements are sufficient to perform fully certified, assumption-free tomography. This is possible without the need to address single sites in any step of the procedure. Combining our approach with tensor network methods-in particular, the theory of matrix product states-we identify situations where the effort of reconstruction is even constant in the number of lattice sites, allowing, in principle, to perform tomography on large-scale systems readily available in present experiments.
A general increase in precipitation has been observed in Germany in the last century, and potential changes in flood generation and intensity are now at the focus of interest. The aim of the paper is twofold: a) to project the future flood conditions in Germany accounting for various river regimes (from pluvial to nival-pluvial regimes) and under different climate scenarios (the high, A2, low, B1, and medium, A1B, emission scenarios) and b) to investigate sources of uncertainty generated by climate input data and regional climate models. Data of two dynamical Regional Climate Models (RCMs), REMO (REgional Model) and CCLM (Cosmo-Climate Local Model), and one statistical-empirical RCM, Wettreg (Wetterlagenbasierte Regionalisierungsmethode: weather-type based regionalization method), were applied to drive the eco-hydrological model SWIM (Soil and Water Integrated Model), which was previously validated for 15 gauges in Germany. At most of the gauges, the 95 and 99 percentiles of the simulated discharge using SWIM with observed climate data had a good agreement with the observed discharge for 1961-2000 (deviation within +/- 10 %). However, the simulated discharge had a bias when using RCM climate as input for the same period. Generalized Extreme Value (GEV) distributions were fitted to the annual maximum series of river runoff for each realization for the control and scenario periods, and the changes in flood generation over the whole simulation time were analyzed. The 50-year flood values estimated for two scenario periods (2021-2060, 2061-2100) were compared to the ones derived from the control period using the same climate models. The results driven by the statistical-empirical model show a declining trend in the flood level for most rivers, and under all climate scenarios. The simulations driven by dynamical models give various change directions depending on region, scenario and time period. The uncertainty in estimating high flows and, in particular, extreme floods remains high, due to differences in regional climate models, emission scenarios and multi-realizations generated by RCMs.
Molecular mechanisms of desiccation tolerance in the resurrection glacial relic Haberlea rhodopensis
(2013)
Haberlea rhodopensis is a resurrection plant with remarkable tolerance to desiccation. Haberlea exposed to drought stress, desiccation, and subsequent rehydration showed no signs of damage or severe oxidative stress compared to untreated control plants. Transcriptome analysis by next-generation sequencing revealed a drought-induced reprogramming, which redirected resources from growth towards cell protection. Repression of photosynthetic and growth-related genes during water deficiency was concomitant with induction of transcription factors (members of the NAC, NF-YA, MADS box, HSF, GRAS, and WRKY families) presumably acting as master switches of the genetic reprogramming, as well as with an upregulation of genes related to sugar metabolism, signaling, and genes encoding early light-inducible (ELIP), late embryogenesis abundant (LEA), and heat shock (HSP) proteins. At the same time, genes encoding other LEA, HSP, and stress protective proteins were constitutively expressed at high levels even in unstressed controls. Genes normally involved in tolerance to salinity, chilling, and pathogens were also highly induced, suggesting a possible cross-tolerance against a number of abiotic and biotic stress factors. A notable percentage of the genes highly regulated in dehydration and subsequent rehydration were novel, with no sequence homology to genes from other plant genomes. Additionally, an extensive antioxidant gene network was identified with several gene families possessing a greater number of antioxidant genes than most other species with sequenced genomes. Two of the transcripts most abundant during all conditions encoded catalases and five more catalases were induced in water-deficient samples. Using the pharmacological inhibitor 3-aminotriazole (AT) to compromise catalase activity resulted in increased sensitivity to desiccation. Metabolome analysis by GC or LC-MS revealed accumulation of sucrose, verbascose, spermidine, and gamma-aminobutyric acid during drought, as well as particular secondary metabolites accumulating during rehydration. This observation, together with the complex antioxidant system and the constitutive expression of stress protective genes suggests that both constitutive and inducible mechanisms contribute to the extreme desiccation tolerance of H. rhodopensis.
A detailed x-ray investigation of zeta puppis - II. the variability on short and long timescales
(2013)
Stellar winds are a crucial component of massive stars, but their exact properties still remain uncertain. To shed some light on this subject, we have analyzed an exceptional set of X-ray observations of zeta Puppis, one of the closest and brightest massive stars. The sensitive light curves that were derived reveal two major results. On the one hand, a slow modulation of the X-ray flux (with a relative amplitude of up to 15% over 16 hr in the 0.3-4.0 keV band) is detected. Its characteristic timescale cannot be determined with precision, but amounts from one to several days. It could be related to corotating interaction regions, known to exist in zeta Puppis from UV observations. Hour-long changes, linked to flares or to the pulsation activity, are not observed in the last decade covered by the XMM observations; the 17 hr tentative period, previously reported in a ROSAT analysis, is not confirmed either and is thus transient, at best. On the other hand, short-term changes are surprisingly small (<1% relative amplitude for the total energy band). In fact, they are compatible solely with the presence of Poisson noise in the data. This surprisingly low level of short-term variability, in view of the embedded wind-shock origin, requires a very high fragmentation of the stellar wind, for both absorbing and emitting features (>10(5) parcels, comparing with a two-dimensional wind model). This is the first time that constraints have been placed on the number of clumps in an O-type star wind and from X-ray observations.
The near-infrared is an important part of the spectrum in astronomy, especially in cosmology because the light from objects in the early universe is redshifted to these wavelengths. However, deep near-infrared observations are extremely difficult to make from ground-based telescopes due to the bright background from the atmosphere. Nearly all of this background comes from the bright and narrow emission lines of atmospheric hydroxyl (OH) molecules. The atmospheric background cannot be easily removed from data because the brightness fluctuates unpredictably on short timescales. The sensitivity of ground-based optical astronomy far exceeds that of near-infrared astronomy because of this long-standing problem. GNOSIS is a prototype astrophotonic instrument that utilizes "OH suppression fibers" consisting of fiber Bragg gratings and photonic lanterns to suppress the 103 brightest atmospheric emission doublets between 1.47 and 1.7 mu m. GNOSIS was commissioned at the 3.9 m Anglo-Australian Telescope with the IRIS2 spectrograph to demonstrate the potential of OH suppression fibers, but may be potentially used with any telescope and spectrograph combination. Unlike previous atmospheric suppression techniques GNOSIS suppresses the lines before dispersion and in a manner that depends purely on wavelength. We present the instrument design and report the results of laboratory and on-sky tests from commissioning. While these tests demonstrated high throughput (approximate to 60%) and excellent suppression of the skylines by the OH suppression fibers, surprisingly GNOSIS produced no significant reduction in the interline background and the sensitivity of GNOSIS+IRIS2 is about the same as IRIS2. It is unclear whether the lack of reduction in the interline background is due to physical sources or systematic errors as the observations are detector noise dominated. OH suppression fibers could potentially impact ground-based astronomy at the level of adaptive optics or greater. However, until a clear reduction in the interline background and the corresponding increasing in sensitivity is demonstrated optimized OH suppression fibers paired with a fiber-fed spectrograph will at least provide a real benefit at low resolving powers.
Disturbances' role in shaping communities is well documented but highly disputed. We suggest replacing the overused two-trait trade-off approach with a functional group scheme, constructed from combinations of four key traits that represent four classes of species' responses to disturbances. Using model results and field observations from sites affected by two highly different disturbances, we demonstrated that popular dichotomous trade-offs are not sufficient to explain community dynamics, even if some emerge under certain conditions. Without disturbances, competition was only sufficient to predict species survival but not relative success, which required some escape mechanism (e.g., long-term dormancy). With highly predictable and large-scale disturbances, successful species showed a combination of high individual tolerance to disturbance and, more surprisingly, high competitive ability. When disturbances were less predictable, high individual tolerance and long-term seed dormancy were favored, due to higher environmental uncertainty. Our study demonstrates that theories relying on a small number of predefined trade-offs among traits (e.g., competition-colonization trade-off) may lead to unrealistic results. We suggest that the understanding of disturbance-community relationships can be significantly improved by employing sets of relevant trait assemblies instead of the currently common approach in which trade-offs are assumed in advance.
A new matrix system for phosphorescent organic light-emitting diodes (OLEDs) based on an electron transporting component attached to an inert polymer backbone, an electronically neutral co-host, and a phosphorescent dye that serves as both emitter and hole conductor are presented. The inert co-host is used either as small molecules or covalently connected to the same chain as the electron-transporting host. The use of a small molecular inert co-host in the active layer is shown to be highly advantageous in comparison to a purely polymeric matrix bearing the same functionalities. Analysis of the dye phosphorescence decay in pure polymer, small molecular co-host film, and their blend lets to conclude that dye molecules distribute mostly in the small molecular co-host phase, where the co-host prevents agglomeration and self-quenching of the phosphorescence as well as energy transfer to the electron transporting units. In addition, the co-host accumulates at the anode interface where it acts as electron blocking layer and improves hole injection. This favorable phase separation between polymeric and small molecular components results in devices with efficiencies of about 47 cd/A at a luminance of 1000 cd/m(2). Investigation of OLED degradation demonstrates the presence of two time regimes: one fast component that leads to a strong decrease at short times followed by a slower decrease at longer times. Unlike the long time degradation, the efficiency loss that occurs at short times is reversible and can be recovered by annealing of the device at 180 degrees C. We also show that the long-time degradation must be related to a change of the optical and electrical bulk properties.
This article examines two so-far-understudied verb doubling constructions in Mandarin Chinese, viz., verb doubling clefts and verb doubling lianaEuro broken vertical bar dou. We show that these constructions have the same internal syntax as regular clefts and lianaEuro broken vertical bar dou sentences, the doubling effect being epiphenomenal; therefore, we classify them as subtypes of the general cleft and lianaEuro broken vertical bar dou constructions, respectively, rather than as independent constructions. Additionally, we also show that, as in many other languages with comparable constructions, the two instances of the verb are part of a single movement chain, which has the peculiarity of allowing Spell-Out of more than one link.
Publication Bias in meta-analyses of the efficacy of psychotherapeutic interventions for depression
(2013)
Objective: The aim of this study was to assess whether systematic reviews investigating psychotherapeutic interventions for depression are affected by publication bias. Only homogeneous data sets were included, as heterogeneous data sets can distort statistical tests of publication bias. Method: We applied Begg and Mazumdar's adjusted rank correlation test, Egger's regression analysis, and the trim and fill procedure to assess the presence and magnitude of publication bias in all homogeneous data sets of systematic reviews published up to September 2010. Results: Thirty-one data sets reported in 19 meta-analyses fulfilled our inclusion criteria. Significant bias was detected in 5 (16.13%; rank correlation test) and 6 (19.35%; Egger's regression analysis) of these data sets. Applying the trim and fill procedure to amend presumably missing studies rarely changed the assessment of the efficacy of therapeutic interventions, with 2 exceptions. In 1 data set psychotherapy was no longer found to be significantly more efficacious than pharmacotherapy in reducing dropout at posttreatment when publication bias was taken into account. In the 2nd data set, after correcting for publication bias, there was no longer evidence that depressed patients without comorbid personality disorder profited more from psychotherapy and pharmacotherapy than patients with comorbid personality disorder. Conclusions: The results suggest that taken together, psychotherapy research for depression is only marginally affected by the selective reporting of positive outcomes. With 2 notable exceptions, correcting for publication bias did not change the evaluation of the efficacy of psychotherapeutic interventions.
This article focuses on the emergence of a decentralized institutional complex, interplay management, and the institutional interplay between the International Maritime Organization (IMO) and the EU in the issue area of environmental shipping policies. It shows that the synergistic relationship between both institutions has been driven primarily by commitment and compliance mechanisms. By influencing IMO decision-making and improving the implementation and effectiveness of IMO conventions, the EU has become a driving force in international environmental shipping policies, and its new initiatives may even enhance its leadership role within the IMO in the future. Despite the still-existing lack of cognitive leadership by the EU, the synergies between both institutions provide evidence for the EU's leadership capacities in global environmental politics.
We classify the existent Birkhoff-type theorems into four classes: first, in field theory, the theorem states the absence of helicity 0- and spin 0-parts of the gravitational field. Second, in relativistic astrophysics, it is the statement that the gravitational far-field of a spherically symmetric star carries, apart from its mass, no information about the star; therefore, a radially oscillating star has a static gravitational far-field. Third, in mathematical physics, Birkhoff's theorem reads: up to singular exceptions of measure zero, the spherically symmetric solutions of Einstein's vacuum field equation with can be expressed by the Schwarzschild metric; for , it is the Schwarzschild-de Sitter metric instead. Fourth, in differential geometry, any statement of the type: every member of a family of pseudo-Riemannian space-times has more isometries than expected from the original metric ansatz, carries the name Birkhoff-type theorem. Within the fourth of these classes we present some new results with further values of dimension and signature of the related spaces; including them are some counterexamples: families of space-times where no Birkhoff-type theorem is valid. These counterexamples further confirm the conjecture, that the Birkhoff-type theorems have their origin in the property, that the two eigenvalues of the Ricci tensor of 2-D pseudo-Riemannian spaces always coincide, a property not having an analogy in higher dimensions. Hence, Birkhoff-type theorems exist only for those physical situations which are reducible to 2-D.
In undisturbed tropical montane rainforests massive organic layers accommodate the majority of roots and only a small fraction of roots penetrate the mineral soil. We investigated the contribution of vegetation to slope stability in such environments by modifying a standard model for slope stability to include an organic layer with distinct mechanical properties. The importance of individual model parameters was evaluated using detailed measurements of soil and vegetation properties to reproduce the observed depth of 11 shallow landslides in the Andes of southern Ecuador. By distinguishing mineral soil, organic layer and above-ground biomass, it is shown that in this environment vegetation provides a destabilizing effect mainly due to its contribution to the mass of the organic layer (up to 973 t ha-1 under wet conditions). Sensitivity analysis shows that the destabilizing effect of the mass of soil and vegetation can only be effective on slopes steeper than 37.9 degrees. This situation applies to 36% of the study area. Thus, on the steep slopes of this megadiverse ecosystem, the mass of the growing forest promotes landsliding, which in turn promotes a new cycle of succession. This feedback mechanism is worth consideration in further investigations of the impact of landslides on plant diversity in similar environments.
Background and Purpose Recent studies suggested a role for PGE2 in the expression of the chemokine IL-8. PGE2 signals via four different GPCRs, EP1-EP4. The role of EP1 and EP4 receptors for IL-8 induction was studied in HEK293 cells, overexpressing EP1 (HEK-EP1), EP4 (HEK-EP4) or both receptors (HEK-EP1 + EP4). Experimental Approach IL-8 mRNA and protein induction and IL-8 promoter and NF-?B activation were assessed in EP expressing HEK cells. Key Results In HEK-EP1 and HEK-EP1 + EP4 but not HEK or HEK-EP4 cells, PGE2 activated the IL-8 promoter and induced IL-8 mRNA and protein synthesis. Stimulation of HEK-EP1 + EP4 cells with an EP1-specific agonist activated IL-8 promoter and induced IL-8 mRNA and protein, whereas a specific EP4 agonist neither activated the IL-8 promoter nor induced IL-8 mRNA and protein synthesis. Simultaneous stimulation of HEK- EP1 + EP4 cells with both agonists activated IL-8 promoter and induced IL-8 mRNA to the same extent as PGE2. In HEK-EP1 + EP4 cells, PGE2-mediated IL-8 promoter activation and IL-8 mRNA induction were blunted by inhibition of I?B kinase. PGE2 activated NF-?B in HEK-EP1, HEK-EP4 and HEK-EP1 + EP4 cells. In HEK-EP1 + EP4 cells, simultaneous activation of both receptors was needed for maximal PGE2-induced NF-?B activation. PGE2-stimulated NF-?B activation by EP1 was blocked by inhibitors of PLC, calcium-signalling and Src-kinase, whereas that induced by EP4 was only blunted by Src-kinase inhibition. Conclusions and Implications These findings suggest that PGE2-mediated NF-?B activation by simultaneous stimulation of EP1 and EP4 receptors induces maximal IL-8 promoter activation and IL-8 mRNA and protein induction.
Cathepsin K (CTSK) is secreted by osteoclasts to degrade collagen and other matrix proteins during bone resorption. Global deletion of Ctsk in mice decreases bone resorption, leading to osteopetrosis, but also increases the bone formation rate (BFR). To understand how Ctsk deletion increases the BFR, we generated osteoclast- and osteoblast-targeted Ctsk knockout mice using floxed Ctsk alleles. Targeted ablation of Ctsk in hematopoietic cells, or specifically in osteoclasts and cells of the monocyte-osteoclast lineage, resulted in increased bone volume and BFR as well as osteoclast and osteoblast numbers. In contrast, targeted deletion of Ctsk in osteoblasts had no effect on bone resorption or BFR, demonstrating that the increased BFR is osteoclast dependent. Deletion of Ctsk in osteoclasts increased their sphingosine kinase 1 (Sphk1) expression. Conditioned media from Ctsk-deficient osteoclasts, which contained elevated levels of sphingosine-l-phosphate (S1P), increased alkaline phosphatase and mineralized nodules in osteoblast cultures. An S1P(1,3) receptor antagonist inhibited these responses. Osteoblasts derived from mice with Ctsk-deficient osteoclasts had an increased RANKL/OPG ratio, providing a positive feedback loop that increased the number of osteoclasts. Our data provide genetic evidence that deletion of CTSK in osteoclasts enhances bone formation in vivo by increasing the generation of osteoclast-derived S1P.
Acetanilides can be deacetylated and diazotized in situ, and subsequently used in Pd-catalyzed coupling reactions without isolation of the diazonium intermediate. Heck reactions, Suzuki cross-coupling reactions, and a Pd-catalyzed [2+2+1]cycloaddition have been investigated as terminating CC bond-forming steps of this one-flask sequence. The sequence does not require the exchange of solvents or removal of by-products between the individual steps, but proceeds by addition of reagents and catalysts in due course.
Plasma secretion of acid sphingomyelinase is a hallmark of cellular stress response resulting in the formation of membrane embedded ceramide-enriched lipid rafts and the reorganization of receptor complexes. Consistently, decompartmentalization of ceramide formation from inert sphingomyelin has been associated with signaling events and regulation of the cellular phenotype. Herein, we addressed the question of whether the secretion of acid sphingomyelinase is involved in host response during sepsis. We found an exaggerated clinical course in mice genetically deficient in acid sphingomyelinase characterized by an increased bacterial burden, an increased phagocytotic activity, and a more pronounced cytokine storm. Moreover, on a functional level, leukocyte-endothelial interaction was found diminished in sphingomyelinase-deficient animals corresponding to a distinct leukocytes' phenotype with respect to rolling and sticking as well as expression of cellular surface proteins.(jlr) We conclude that hydrolysis of membrane-embedded sphingomyelin, triggered by circulating sphingomyelinase, plays a pivotal role in the first line of defense against invading microorganisms. This function might be essential during the early phase of infection leading to an adaptive response of remote cells and tissues.-Jbeily, N., I. Suckert, F. A. Gonnert, B. Acht, C. L. Bockmeyer, S. D. Grossmann, M. F. Blaess, A. Lueth, H.-P. Deigner, M. Bauer, and R. A. Claus. Hyperresponsiveness of mice deficient in plasma-secreted sphingomyelinase reveals its pivotal role in early phase of host response. J. Lipid Res. 2013. 54: 410-424.
Molecular rods consisting of a hydrophobic backbone and terminally varying functional groups have been synthesized for applications for the functionalization of membranes. In the present study, we employ a spin-labeled analogue of a recently described new class of molecular rods to characterize their dynamic interactions with membranes. By using the different approaches of ESR and NMR spectroscopy, we show that the spin moiety of the membrane-embedded spin-labeled rod is localized in the upper chain/glycerol region of membranes of different compositions. The rod is embedded within the membrane in a tilted orientation to adjust for the varying hydrophobic thicknesses of these bilayers. This orientation does not perturb the membrane structure. The water solubility of the rod is increased significantly in the presence of certain cyclodextrins. These cyclodextrins also allow the rods to be extracted from the membrane and incorporated into preformed membranes. The latter will improve the future applications of these rods in cellular systems as stable membrane-associated anchors for the functionalization of membrane surfaces.
We report on the fabrication, modeling, and experimental verification of the emission of fiber lenses fabricated on multimode fibers in different media. Concave fiber lenses with a radius of 150 mu m were fabricated onto a multimode silica fiber (100 mu m core) by grinding and polishing against a ruby sphere template. In our theoretical model we assume that the fiber guides light from a Lambertian light source and that the emission cone is governed solely by the range of permitted emission angles. We investigate concave and convex lenses at 532 nm with different radii and in a variety of surrounding media from air (n(0) = 1.00) to sapphire (n(0) = 1.77). It was found that noticeable focusing or defocusing effects of a silica fiber lens in ethanol (n(0) = 1.36) and dimethyl sulfoxide (DMSO) (n(0) = 1.48) are only observed when the fiber lens radius was less than the fiber diameter.
A species of Galapagos tortoise endemic to Espanola Island was reduced to just 12 females and three males that have been bred in captivity since 1971 and have produced over 1700 offspring now repatriated to the island. Our molecular genetic analyses of juveniles repatriated to and surviving on the island indicate that none of the tortoises sampled in 1994 had hatched on the island versus 3% in 2004 and 24% in 2007, which demonstrates substantial and increasing reproduction in situ once again. This recovery occurred despite the parental population having an estimated effective population size <8 due to a combination of unequal reproductive success of the breeders and nonrandom mating in captivity. These results provide guidelines for adapting breeding regimes in the parental captive population and decreasing inbreeding in the repatriated population. Using simple morphological data scored on the sampled animals, we also show that a strongly heterogeneous distribution of tortoise sizes on Espanola Island observed today is due to a large variance in the number of animals included in yearly repatriation events performed in the last 40years. Our study reveals that, at least in the short run, some endangered species can recover dramatically despite a lack of genetic variation and irregular repatriation efforts.
Context. The Tarantula Nebula (a.k.a. 30 Dor) is a spectacular star-forming region in the Large Magellanic Cloud (LMC), seen through gas in the Galactic disc and halo. Diffuse interstellar bands (DIBs) offer a unique probe of the diffuse, cool-warm gas in these regions.
Aims. The aim is to use DIBs as diagnostics of the local interstellar conditions, whilst at the same time deriving properties of the yet-unknown carriers of these enigmatic spectral features.
Methods. Spectra of over 800 early-type stars from the Very Large Telescope Flames Tarantula Survey (VFTS) were analysed. Maps were created, separately, for the Galactic and LMC absorption in the DIBs at 4428 and 6614 angstrom and - in a smaller region near the central cluster R 136 - neutral sodium (the Na ID doublet); we also measured the DIBs at 5780 and 5797 angstrom.
Results. The maps show strong 4428 and 6614 angstrom DIBs in the quiescent cloud complex to the south of 30 Dor but weak absorption in the harsher environments to the north (bubbles) and near the OB associations. The Na maps show at least five kinematic components in the LMC and a shell-like structure surrounding R 136, and small-scale structure in the Milky Way. The strengths of the 4428, 5780, 5797 and 6614 angstrom DIBs are correlated, also with Na absorption and visual extinction. The strong 4428 angstrom DIB is present already at low Na column density but the 6614, 5780 and 5797 angstrom DIBs start to be detectable at subsequently larger Na column densities.
Conclusions. The carriers of the 4428, 6614, 5780 and 5797 angstrom DIBs are increasingly prone to removal from irradiated gas. The relative strength of the 5780 and 5797 angstrom DIBs clearly confirm the Tarantula Nebula as well as Galactic high-latitude gas to represent a harsh radiation environment. The resilience of the 4428 angstrom DIB suggests its carrier is large, compact and neutral. Structure is detected in the distribution of cool-warm gas on scales between one and > 100 pc in the LMC and as little as 0.01 pc in the Sun's vicinity. Stellar winds from the central cluster R 136 have created an expanding shell; some infalling gas is also detected, reminiscent of a galactic "fountain".
We use archival UV absorption-line data from HST/STIS to statistically analyse the absorption characteristics of the high-velocity clouds (HVCs) in the Galactic halo towards more than 40 extragalactic background sources. We determine absorption covering fractions of low-and intermediate ions (Oi, Cii, Si ii, Mgii, Feii, Si iii, Civ, and Si iv) in the range f(c) = 0.20-0.70. For detailed analysis we concentrate on Si ii absorption components in HVCs, for which we investigate the distribution of column densities, b-values, and radial velocities. Combining information for Si ii and Mg II, and using a geometrical HVC model we investigate the contribution of HVCs to the absorption cross section of strong Mg ii absorbers in the local Universe. We estimate that the Galactic HVCs would contribute on average similar to 52 percent to the total strong Mg ii cross section of the Milky Way, if our Galaxy were to be observed from an exterior vantage point. We further estimate that the mean projected covering fraction of strong Mg ii absorption in the Milky Way halo and disc from an exterior vantage point is < f(c,sMgII)> = 0.31 for a halo radius of R = 61 kpc. These numbers, together with the observed number density of strong Mg ii absorbers at low redshift, indicate that the contribution of infalling gas clouds (i.e., HVC analogues) in the halos of Milky Way-type galaxies to the cross section of strong Mgii absorbers is < 34 percent. These findings are in line with the idea that outflowing gas (e. g., produced by galactic winds) in the halos of more actively star-forming galaxies dominate the absorption-cross section of strong Mgii absorbers in the local Universe.
From the surface exudates of Senecio roseiflorus fourteen known methylated flavonoids and one phenol were isolated and characterized. The structures of these compounds were determined on the basis of their spectroscopic analysis. The surface exudate and the flavonoids isolated showed moderate to good antiplasmodial activity with 5,4'-dihydroxy-7-dimethoxyflavanone having the highest activity against chloroquine-sensitive (D6) and resistant (W2) strains of Plasmodium falciparum, with IC50 values of 3.2 +/- 0.8 and 4.4 +/- 0.01 mu g/mL respectively.
Aims Recent studies have demonstrated the safety and efficacy of catheter-based renal sympathetic denervation (RDN) for the treatment of resistant hypertension. We aimed to determine the cost-effectiveness of this approach separately for men and women of different ages.
Methods and results A Markov state-transition model accounting for costs, life-years, quality-adjusted life-years (QALYs), and incremental cost-effectiveness was developed to compare RDN with best medical therapy (BMT) in patients with resistant hypertension. The model ran from age 30 to 100 years or death, with a cycle length of 1 year. The efficacy of RDN was modelled as a reduction in the risk of hypertension-related disease events and death. Analyses were conducted from a payer's perspective. Costs and QALYs were discounted at 3% annually. Both deterministic and probabilistic sensitivity analyses were performed. When compared with BMT, RDN gained 0.98 QALYs in men and 0.88 QALYs in women 60 years of age at an additional cost of (sic)2589 and (sic)2044, respectively. As the incremental cost-effectiveness ratios increased with patient age, RDN consistently yielded more QALYs at lower costs in lower age groups. Considering a willingness-to-pay threshold of (sic)35 000/QALY, there was a 95% probability that RDN would remain cost-effective up to an age of 78 and 76 years in men and women, respectively. Cost-effectiveness was influenced mostly by the magnitude of effect of RDN on systolic blood pressure, the rate of RDN non-responders, and the procedure costs of RDN.
Conclusion Renal sympathetic denervation is a cost-effective intervention for patients with resistant hypertension. Earlier treatment produces better cost-effectiveness ratios.