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In precision agriculture geoelectrical methods have shown their capability to detect spatial variation of important physico-chemical soil parameters in an efficient way. Nevertheless, relationships between the electrical parameters (electrical conductivity or resistivity) and other soil properties are not always consistent over different fields. This can, to some extent, be due to the characteristics of instruments used for soil mapping. However, a limited amount of research has addressed this issue. In this study, seven instruments for mobile mapping (continuous geoelectrical measurements) available on the market were tested (ARP 03, CM-138, EM38, EM38-DD, EM38-MK2, OhmMapper and Veris 3100). Instruments were employed on a sandy site in north-east Germany. Measurements were compared to a profile, which has been investigated with a high accuracy reference. Additional investigations were conducted concerning the influences of temperature drift, seasonal variations and soil properties on soil EC. Marked differences between the instruments were found with respect to depth of investigation, accuracy and handling that have to be taken into account when geoelectrical surveys are planned or interpreted. Regarding depth of investigation and robustness of the measurements, ARP 03 and Veris 3100 seem to be the most suitable instruments for precision agriculture.
Polymer-dispersed liquid crystals (PDLCs) are prepared from poly(vinylidene fluoride-trifluoroethylene) (P(VDF- TrFE)) and a nematic liquid-crystal (LC). The anchoring effect was studied using dielectric relaxation spectroscopy. Two dispersion regions are observed in the dielectric spectra of the pure P(VDF-TrFE) film. They are related to the glass transition and to a space-charge relaxation. In PDLC films containing 10 wt% of LC, an additional, bias field-dependent relaxation peak is found that can be attributed to the motion of LC molecules. Due to the hindered movement of the LC molecules, this relaxation process is considerably slowed down, compared with the related process in the pure LC.
Distinct roles of the last transmembrane domain in controlling Arabidopsis K+ channel activity
(2009)
The family of voltage-gated potassium channels in plants presumably evolved from a common ancestor and includes both inward-rectifying (K-in) channels that allow plant cells to accumulate K+ and outward-rectifying (K-out) channels that mediate K+ efflux. Despite their close structural similarities, the activity of Kin channels is largely independent of K+ and depends only on the transmembrane voltage, whereas that of K-out channels responds to the membrane voltage and the prevailing extracellular K+ concentration. Gating of potassium channels is achieved by structural rearrangements within the last transmembrane domain (S6). Here we investigated the functional equivalence of the S6 helices of the Kin channel KAT1 and the K-out channel SKOR by domain-swapping and site-directed mutagenesis. Channel mutants and chimeras were analyzed after expression in Xenopus oocytes. We identified two discrete regions that influence gating differently in both channels, demonstrating a lack of functional complementarity between KAT1 and SKOR. Our findings are supported by molecular models of KAT1 and SKOR in the open and closed states. The role of the S6 segment in gating evolved differently during specialization of the two channel subclasses, posing an obstacle for the transfer of the K+-sensor from K-out to K-in channels.
We employ a spectral decomposition method to analyze synchronization of a non-identical oscillator network. We study the case that a small parameter mismatch of oscillators is characterized by one parameter and phase synchronization is observed. We derive a linearized equation for each eigenmode of the coupling matrix. The parameter mismatch is reflected on inhomogeneous term in the linearized equation. We find that the oscillation of each mode is essentially characterized only by the eigenvalue of the coupling matrix with a suitable normalization. We refer to this property as spectral universality, because it is observed irrespective of network topology. Numerical results in various network topologies show good agreement with those based on linearized equation. This universality is also observed in a system driven by additive independent Gaussian noise.
Films of anthracene carboxylic acids were irradiated through photomasks and oxidized at the exposed regions by singlet oxygen upon sensitization. The efficiency of a photomask to protect the material underneath was investigated by optical and infrared spectroscopy. As the thickness of the film is reduced, the efficiency of the mask drops. This is explained by the migration of singlet oxygen at the solid-air interface, which in turn reacts at the masked area. For films with a thickness of < 15 nm, the efficiency of the mask approaches zero: sufficient efficiency is achieved at thicknesses > 100 nm. From the investigations, it will become clear that the contrast between the irradiated and masked area of an image is affected by reduction of the film thickness. On the other hand, the resolution of an image, which relates to the minimum feature size of an image, is not dependent on the thickness of the film. The contributions of "inside" and "outside" reactions are examined separately, and it quantitative approximation of the spatial range of both modes of the oxygenation is given. We set tip an approximate relation between mask efficiency and experimental conditions comprising internal and external oxygen diffusion, film thickness, and mask dimensions. These results give it deeper insight into the limits of resolution and contrast in singlet oxygen lithography.
Retinol-binding protein 4 (RBP4) is an adipokine bound in plasma to transthyretin (TTR), which prevents its glomerular filtration and subsequent catabolism in the kidney. Alterations of this interaction have been Suggested to be implicated in the elevation of RBP4 that are thought to contribute to the development Of insulin resistance associated with obesity and type 2 diabetes mellitus (T2DM). However, the factors linking RBP4 to TTR in humans are not clear. Therefore, this Study evaluated parameters influencing the RBP4-TTR interaction and their relation to obesity and T2DM. The RBP4 and TTR levels were quantified in plasma of 16 lean controls, 28 overweight controls, and 14 overweight T2DM patients by enzyme-linked immunosorbent assay. Transthyretin isoforms involved in RBP4 binding were determined by linear matrix-assisted laser desorption/ionization-time of flight-mass spectrometry after RBP4 coimmunoprecipitation. Holo-RBP4 (retinol-bound) and apo-RBP4 (retinol-free) were assessed by immunoblotting using nondenaturating polyacrylamide gel electrophoresis. Plasma levels of both RBP4 and TTR did not differ among the groups of lean controls, overweight controls, and overweight T2DM subjects. Using RBP4 immunoprecipitation, 4 mass signals were observed for TTR representing native, S-cysteinylated, S-cysteinglycinylated, and S-glutathionylated TTR. No differences in peak intensity of TTR isoforms were observed among the groups. Moreover, no differences in the ratio of holo- and apo-RBP4 were evident. The results suggest that circulating RBP4 and TTR were not affected by human obesity or T2DM, which might be attributed to the absence of alterations of TTR isoforms and the ratio of holo- and apo-RBP4 that might modify the TTR-RBP4 interaction.
Background: Retinol-binding protein 4 (RBP4) levels are elevated in the serum of patients with kidney dysfunction. We recently showed that RBP4 isoforms including apo-RBP4 (RBP4 not bound to retinol) and RBP4 truncated at the C-terminus (RBP4-L, RBP4-LL) are increased in the serum of patients with kidney diseases but not in serum of patients with various liver diseases. The aim of this study was to investigate the effect of renal replacement therapy on RBP4 isoforms. Methods: We investigated serum levels of RBP4, apo-RBP4, holo-RBP4, RBP4-L, RBP4-LL, retinol and transthyretin (TTR) in 18 hemodialysis (HD) patients, 30 patients after renal transplantation (RTx) and in 35 healthy controls. RBP4 and TTR levels were measured by enzyme-linked immunosorbent assay, apo- and holo-RBP4 by native electrophoresis, retinol by high performance liquid chromatography and RBP4-L and RBP4-LL were analyzed by mass spectrometry. Results: HD and RTx patients had elevated RBP4, apo-RBP4 and RBP4-LL levels compared to controls. RTx patients had elevated amounts of RBP4-L compared to controls and elevated RBP4 and apo-RBP4 levels compared to HD patients. Conclusion: The results demonstrate a strong correlation between kidney function and RBP4 isoforms and provide data for investigating the relation of RBP4 and insulin resistance in these patients.
The Aue-Schwarzenberg Granite Zone (ASGZ), in the western Erzgebirge of Germany, is composed of small, late- Variscan F-poor biotite and two-mica granites. The biotite granites (Aue granite suite, Beierfeld, Bernsbach) are weakly to mildly peraluminous (A/CNK = 1.07-1.14; 70-76 wt% SiO2), display similar Sr-87/Sr-86 initial ratios (0.7065-0.7077; t = 325 Ma), and exhibit a narrow range in epsilon Nd-325 (-2.6 to -3.5). They are closely affiliated compositionally with the biotite granites in the distant, more voluminous Nejdek massif (Czech Republic). The two-mica granites (Schwarzenberg granite suite, Lauter) are Si-rich (74-77 wt% SiO2) and mildly to strongly peraluminous (A/CNK = 1.17- 1.26). The granites from Schwarzenberg Lire distinctly higher in their Sr(i)ratios (0.709-0.713; t = 325 Ma) and possess lower values of epsilon Nd-325 (-4.9 to -5.2) relative to the biotite granites. The Lauter granites have a Nd-isotopic composition between -3.6 and -4.0 (t = 325 Ma). Mean Th-U-total Pb uraninite ages (Ma +/- 2 sigma) obtained for the granites from the Aue Suite (324.3 +/- 3. 1), Beierfeld (323.7 +/- 3.1), Bernsbach (320.7 +/- 2.9), Schwarzenberg (323.3 +/- 2.4), and the Kirchberg granite al Burkersdorf (322.7 +/- 3.5) indicate that magmatism in the ASGZ commenced in the Namurian and took place early within the major episode of granite formation in the Erzgebirge-Vogtland zone (327-318 Ma). Geochemical and mineralogical patterns of variably altered samples imply that the ASGZ granites are unlikely to have significantly contributed to the formation of spatially associated metalliferous ore deposits (Sn, W, Mo, Ph, Zn, Bi, Co, Ni), except for uranium. In particular the Aue granite suite should have served as major Source for U accumulated in the economically important post-granitic deposits of Schneeberg and Schlema-Alberoda.
Experimental evidences point Out the participation of nonsynaptic mechanisms (e.g., fluctuations in extracellular tons) in epileptiform bursting and spreading depression (SD). During these abnormal oscillatory patterns, it is observed an increase of extracellular potassium concentration [K+](o) and a decrease of extracellular calcium concentration [Ca2+](o) which raises the neuronal excitability. However, whether the high [K+](o) triggers and propagates these abnormal neuronal activities or plays a secondary role into this process is unclear. To better understand the influence of extracellular potassium dynamics in these oscillatory patterns, the experimental conditions of high [K+](o) and zero [Ca2+](o) were replicated in an extended Golomb model where we added important regulatory mechanisms of ion concentration as Na+-K+ pump, ion diffusion and glial buffering. Within these Conditions, simulations of the cell model exhibit seizure-like discharges (ictal bursting). The SD was elicited by the interruption of the Na+- K+ pump activity, mimicking the effect of cellular hypoxia (an experimental protocol to elicit SD, the hypoxia-induced SD). We used the bifurcation theory and the fast-slow method to analyze the interference of K+ dynamics in the cellular excitability. This analysis indicates that the system loses its stability at a high [K+](o), transiting to an elevated state of neuronal excitability. Effects of high [K+](o), are observed in different stages of ictal bursting and SD. In the initial stage, the increase of [K+](o) creates favorable conditions to trigger both oscillatory patterns. During the neuronal activity, a continuous growth of [K+](o) by outward K+ flow depresses K+ Currents in a positive feedback way. At the last stage, due to the depression of K+ currents, the Na+-K+ pump is the main mechanism in the end of neuronal activity. Thus, this work suggests that [K+](o) dynamics may play a fundamental role in these abnormal oscillatory patterns.
The purpose of this study was to investigate whether neural adaptations following functional multiple-joint leg press training can induce neural adaptations to the plantar flexor muscles in a single-joint contraction task. Subjects were randomised to a maximal strength training (MST) (n = 10) or a control group (n = 9). MST consisted of 24 sessions (8 weeks) of 4 x 4 repetitions of horizontal leg press using maximal intended velocity in the concentric phase with the movement ending in a plantar flexion. Neural adaptations in the soleus and gastrocnemius medialis (GM) were assessed by surface electromyographic activity and V-waves during maximum voluntary isometric contraction (MVIC), and also by H- reflexes in the soleus during rest and 20% MVIC. One repetition maximum leg press increased by 44 +/- A 14% (mean +/- A SD; P < 0.01). Plantar flexion MVIC increased by 20 +/- A 14% (P < 0.01), accompanied by 13 +/- A 19% (P < 0.05) increase in soleus, but not GM surface electromyography. Soleus V/M-SUP increased by 53 +/- A 66% and in GM by 59 +/- A 64% (P < 0.05). Normalised soleus H-reflexes remained unchanged by training. No changes occurred in the control group. These results suggest that leg press MST can induce neural adaptations in a single-joint plantar flexion MVIC task.
This prospective longitudinal study of a representative community sample of children and adolescents (N = 269) examined the long-term course and predictive power of psychiatric symptoms in childhood/adolescence for diagnostic outcome (ICD-10) 18 years later at adult age. At both cross-sectional assessments, baseline (1980-1984) and the 18-year follow-up (2001-2004), psychiatric symptoms were assessed using the 'Standardized Psychiatric Interview' (Goldberg et al. in Br J Prev Soc Med 24:18-23, 1970). At follow-up, study participants were reassessed with the standardized M-CIDI (Wittchen and Pfister in Manual und Durchfuhrungsbeschreibung des DIA-X-M-CIDI, Swets and Zeitlinger, Frankfurt, 1997) interview. The participation rate at 18-year follow-up was 82% of those alive. The frequency of clinically relevant depressive symptoms and symptoms of anxiety or phobia was considerably higher when the participants were younger (baseline assessment at childhood, adolescent age) as compared to their scores in adult age. Increased levels of somatic symptoms, fatigue, irritability, sleep disturbances, depression, anxiety and worry as well as phobic symptoms in childhood/adolescence were related to a higher risk of suffering from a psychiatric disorder in adulthood. Depressive symptoms predicted both mood disorders and substance use disorders in adulthood. Phobias predicted later anxiety disorders. These data spanning almost two decades add significant information to the existing literature on the course of mental disorders in the community during the transition from adolescence to adulthood.
Mate choice is mediated by a range of sensory cues, and assortative mating based on these cues can drive reproductive isolation among diverging populations. A specific feature of mormyrid fish, the electric organ discharge (EOD), is used for electrolocation and intraspecific communication. We hypothesized that the EOD also facilitates assortative mating and ultimately promotes prezygotic reproductive isolation in African weakly electric fishes. Our behavioural experiments using live males as well as EOD playback demonstrated that female mate recognition is influenced by EOD signals and that females are attracted to EOD characteristics of conspecific males. The dual function of the EOD for both foraging and social communication (including mate recognition leading to assortative mating) underlines the importance of electric signal differentiation for the divergence of African weakly electric fishes. Thus, the EOD provides an intriguing mechanism promoting trophic divergence and reproductive isolation between two closely related Campylomormyrus species occurring in sympatry in the lower Congo rapids.
In plants several 'starch-related' enzymes exist as plastid- and cytosol-specific isoforms and in some cases the extraplastidial isoforms represent the majority of the enzyme activity. Due to the compartmentation of the plant cells, these extraplastidial isozymes have no access to the plastidial starch granules and, therefore, their in vivo function remained enigmatic. Recently, cytosolic heteroglycans have been identified that possess a complex pattern of the monomer composition and glycosidic bonds. The glycans act both as acceptors and donors for cytosolic glucosyl transferases. In autotrophic tissues the heteroglycans are essential for the nocturnal starch-sucrose conversion. In this review we summarize the current knowledge of these glycans, their interaction with glucosyl transferases and their possible cellular functions. We include data on the heteroglycans in heterotrophic plant tissues and discuss their role in intracellular carbon fluxes that originate from externally supplied carbohydrates.
Starch is an important plant product widely used as a nutrient, as a source of renewable energy, and for many technological applications. In plants, starch is the almost ubiquitous storage carbohydrate whereas most heterotrophic prokaryotes and eukaryotes rely on glycogen. Despite close similarities in basic chemical features, starch and glycogen differ in both structural and physicochemical properties. Glycogen is a hydrosoluble macromolecule with evenly distributed branching points. Starch exists as a water-insoluble particle having a defined (and evolutionary conserved) internal structure. The biochemistry of starch requires the co-operation of up to 40 distinct (iso)enzymes whilst approximately 10 (iso)enzymes permit glycogen metabolism. The biosynthesis and degradation of native starch include the transition of carbohydrates from the soluble to the solid phase and vice versa. In this review, two novel aspects of the eukaryotic plastidial starch degradation are discussed: Firstly, biochemical reactions that take place at the surface of particulate glucans and mediate the phase transition of carbohydrates. Secondly, processes that occur downstream of the export of starch-derived sugars into the cytosol. Degradation of transitory starch mainly results in the formation of neutral sugars, such as glucose and maltose, that are transported into the cytosol via the respective translocators. The cytosolic metabolism of the neutral sugars includes the action of a hexokinase, a phosphoglucomutase, and a transglucosidase that utilizes high molecular weight glycans as a transient glucosyl acceptor or donor. Data are included on the transglucosidase (disproportionating isozyme 2) in Cyanophora paradoxa that accumulates storage carbohydrates in the cytosol rather than in the plastid.
This paper investigates the question of whether and how 'Second Occurrence Focus' (SOF) is realized phonetically in German. The apparent lack of phonetic marking on SOF has raised much discussion oil the semantic theory Of focus (Partee 1999, Rooth 1992). Some researchers have reported the existence of phonetic marking of SOF in the postnuclear area (Rooth 1996, Beaver et al. 2007). In our experimental study with German sentences, we examined sentences both with prenuclear SOF and with postnuclear SOF, comparing them with their first occurrence focus (FOF) and non-focus counterparts. The results show that the phonetic prominence of focus (higher pitch/longer duration) is realized differently according to the type of focus as well as according to the position of the target expression. We account for these differences by considering several phonetic effects, those that are information-structure-related and those that are phonologically motivated.
Recent efforts have applied quantum tomography techniques to the calibration and characterization of complex quantum detectors using minimal assumptions. In this work, we provide detail and insight concerning the formalism, the experimental and theoretical challenges and the scope of these tomographical tools. Our focus is on the detection of photons with avalanche photodiodes and photon-number resolving detectors and our approach is to fully characterize the quantum operators describing these detectors with a minimal set of well-specified assumptions. The formalism is completely general and can be applied to a wide range of detectors.
Epitaxial ferroelectric PbZr0.2Ti0.8O3 thin films were grown by pulsed laser deposition. PbZr0.2Ti0.8O3 was doped with Cr acting as acceptor ion. Microstructural characterization was performed by (high resolution) transmission electron microscopy. The voltage dependence of polarization, dielectric constant, and leakage current were measured with respect to the Cr content. To derive the electronic properties, PZT was considered as a wide-gap semiconductor which allows treating the metal-PZT interface as a Schottky contact. The Cr was found to facilitate the elastic relaxation of the film. Furthermore, the leakage current was increased through a reduction of the Schottky barrier.
Aims: We present a study of Nv absorption systems at 1.5 less than or similar to z less than or similar to 2.5 in the spectra of 19 QSOs, based on data obtained with the VLT/UVES instrument. Our analysis includes both the absorbers arising from the intergalactic medium, as well as systems in the vicinity of the background quasar. Methods: We construct detailed photoionization models to study the physical conditions and abundances in the absorbers and to constrain the spectral hardness of the ionizing radiation. Results: The rate of incidence for intervening Nv components is dN/dz = 3.38 +/- 0.43, corresponding to dN/dX = 1.10 +/- 0.14. The column density distribution function is fitted by the slope beta = 1.89 +/- 0.22, consistent with measurements of CIV and OVI. The narrow line widths (b(Nv) similar to 6 kms(-1)) imply photoionization rather than collisions as the dominating ionization process. The column densities of CIV and NV are correlated but show different slopes for intervening and associated absorbers, which indicates different ionizing spectra. Associated systems are found to be more metal-rich, denser, and more compact than intervening absorbers. This conclusion is independent of the adopted ionizing radiation. For the intervening NV systems we find typical values of [C/H] similar to-0.6 and n(II) similar to 10-3.6 cm(-3) and sizes of a few kpc, while for associated Nv absorbers we obtain [C/H] similar to + 0.7, n(II) similar to 10(-2.8) cm(-3) and sizes of several 10 pc. The abundance of nitrogen relative to carbon [N/C] and alpha-elements like oxygen and silicon [N/alpha] is correlated with [N/H], indicating the enrichment by secondary nitrogen. The larger scatter in [N/alpha] in intervening systems suggests an inhomogeneous enrichment of the IGM. There is an anti-correlation between [N/alpha] and [alpha/C], which could be used to constrain the initial mass function of the carbon-and nitrogen-producing stellar population.
We consider theoretically the dynamics of an oscillated sessile drop of incompressible liquid and focus on the contact line hysteresis. We address the situation of the small-amplitude and high-frequency oscillations imposed normally to the substrate surface. We deal with the drop whose equilibrium surface is hemispherical and the equilibrium contact angle equals pi/2. We apply the dynamic boundary condition that involves an ambiguous dependence of the contact angle on the contact line velocity: The contact line starts to slide only when the deviation of the contact angle exceeds a certain critical value. As a result, the stick-slip dynamics can be observed. The frequency response of surface oscillations on the substrate and at the pole of the drop are analyzed. It is shown that novel features such as the emergence of antiresonant frequency bands and nontrivial competition of different resonances are caused by contact line hysteresis.
The aim of this paper is to characterize the spatio-temporal distribution of Central-Europe seismicity. Specifically, by using a non-parametric statistical approach, the proportional hazard model, leading to an empirical estimation of the hazard function, we provide some constrains on the time behavior of earthquake generation mechanisms. The results indicate that the most conspicuous characteristics of M-w 4.0+ earthquakes is a temporal clustering lasting a couple of years. This suggests that the probability of occurrence increases immediately after a previous event. After a few years, the process becomes almost time independent. Furthermore, we investigate the cluster properties of the seismicity of Central-Europe, by comparing the obtained result with the one of synthetic catalogs generated by the epidemic type aftershock sequences (ETAS) model, which previously have been successfully applied for short term clustering. Our results indicate that the ETAS is not well suited to describe the seismicity as a whole, while it is able to capture the features of the short- term behaviour. Remarkably, similar results have been previously found for Italy using a higher magnitude threshold.
Achievement motive imagery in German schoolbooks : a pilot study testing McClelland's hypothesis
(2009)
McClelland [McClelland, D.C. (1961). The achieving society. Princeton, NJ: Van Nostrand] observed that the amount of achievement imagery in children's books predicted the economic development of societies. He argued that achievement imagery is an indicator of a motivational climate, and when children grow up in a society that emphasizes the striving for achievement, they will be more economically productive later on. We tested McClelland's hypothesis by coding school textbooks for achievement imagery from two German federal states (Baden-Wurttemberg and Bremen) with pronounced differences in economic and educational conditions. As expected, the schoolbooks from the state with the more advantageous conditions contained more achievement imagery.
Phosphorus meets carbohydrates: Dimethyl phosphite reacts with ceric(IV) ammonium nitrate (CAN) to give phosphonyl radicals that add to glycals 1. The derivatives 2 were isolated in high yields and during a subsequent Horner-Emmons reaction underwent an interesting elimination to give 3,6-dihydro-2H-pyrans 3. The short sequence with simple precursors is applicable to the transformation of hexoses, pentoses, and disaccharides. Bn=benzyl.
When locally exciting a quantum lattice model, the excitation will propagate through the lattice. This effect is responsible for a wealth of nonequilibrium phenomena, and has been exploited to transmit quantum information. It is a commonly expressed belief that for local Hamiltonians, any such propagation happens at a finite "speed of sound". Indeed, the Lieb-Robinson theorem states that in spin models, all effects caused by a perturbation are essentially limited to a causal cone. We show that for meaningful translationally invariant bosonic models with nearest-neighbor interactions (addressing the challenging aspect of an experimental realization) this belief is incorrect: We prove that one can encounter accelerating excitations under the natural dynamics that allow for reliable transmission of information faster than any finite speed of sound. It also implies that the simulation of dynamics of strongly correlated bosonic models may be much harder than that of spin chains even in the low-energy sector.
Gating of K+ and other ion channels is 'hard-wired' within the channel protein. So it remains a puzzle how closely related channels in plants can show an unusually diverse range of biophysical properties. Gating of these channels lies at the heart of K+ mineral nutrition, signalling, abiotic and biotic stress responses in plants. Thus, our knowledge of the molecular mechanics underpinning K+ channel gating will be important for rational engineering of related traits in agricultural crops. Several key studies have added significantly to our understanding of channel gating in plants and have challenged current thinking about analogous processes found in animal K+ channels. Such studies highlight how much of K+ channel gating remains to be explored in plants.
Complex networks in climate dynamics : comparing linear and nonlinear network construction methods
(2009)
Complex network theory provides a powerful framework to statistically investigate the topology of local and non- local statistical interrelationships, i.e. teleconnections, in the climate system. Climate networks constructed from the same global climatological data set using the linear Pearson correlation coefficient or the nonlinear mutual information as a measure of dynamical similarity between regions, are compared systematically on local, mesoscopic and global topological scales. A high degree of similarity is observed on the local and mesoscopic topological scales for surface air temperature fields taken from AOGCM and reanalysis data sets. We find larger differences on the global scale, particularly in the betweenness centrality field. The global scale view on climate networks obtained using mutual information offers promising new perspectives for detecting network structures based on nonlinear physical processes in the climate system.
Quantum chemical calculations of various azobenzene (AB) derivatives have been carried out with the goal to describe the energetics and kinetics of their thermal cis -> trans isomerization. The effects of substituents, in particular their type, number, and positioning, on activation energies have been systematically studied with the ultimate goal to tailor the switching process. Trends observed for mono- and disubstituted species are discussed. A polarizable continuum model is used to study, in an approximate fashion, the cis -> trans isomerization of azobenzenes in solution. The nature of the transition state(s) and its dependence on substituents and the environment is discussed. In particular for push-pull azobenzenes, the reaction mechanism is found to change from inversion in nonpolar solvents to rotation in polar solvents. Concerning kinetics, calculations based on the Eyring transition state theory give usually reliable activation energies and enthalpies when compared to experimentally determined values. Also, trends in the resulting rate constants are correct. Other computed properties such as activation entropies and thus preexponential rate factors are in only moderate agreement with experiment.
We present a technique for pulse recovery based on real-time measurement of the differential optical phase spectrum from spectral interference patterns. Using a phase retrieval algorithm we can obtain accurate all order polarization mode dispersion (PMD) information for the optical signal and correspondingly compensate the impairment in optical transmission lines. Linear PMD is accurately extracted from measurements, and analytical simulations show recovery of pulses distorted by higher order PMD.
Superconductors are considered in view of applications to atom chip devices. The main features of magnetic traps based on superconducting wires in the Meissner and mixed states are discussed. The former state may mainly be interesting for improved atom optics, while in the latter, cold atoms may provide a probe of superconductor phenomena. The properties of a magnetic side guide based on a single superconducting strip wire placed in an external magnetic field are calculated analytically and numerically. In the mixed state of type II superconductors, inhomogeneous trapped magnetic flux, relaxation processes and noise caused by vortex motion are posing specific challenges for atom trapping.
Mechanism of substrate and inhibitor binding of Rhodobacter capsulatus xanthine dehydrogenase
(2009)
Rhodobacter capsulatus xanthine dehydrogenase (XDH) is an (alpha beta)(2) heterotetrameric cytoplasmic enzyme that resembles eukaryotic xanthine oxidoreductases in respect to both amino acid sequence and structural fold. To obtain a detailed understanding of the mechanism of substrate and inhibitor binding at the active site, we solved crystal structures of R. capsulatus XDH in the presence of its substrates hypoxanthine, xanthine, and the inhibitor pterin-6- aldehyde using either the inactive desulfo form of the enzyme or an active site mutant (E(B)232Q) to prevent substrate turnover. The hypoxanthine-and xanthine-bound structures reveal the orientation of both substrates at the active site and show the importance of residue GluB-232 for substrate positioning. The oxygen atom at the C-6 position of both substrates is oriented toward Arg(B)-310 in the active site. Thus the substrates bind in an orientation opposite to the one seen in the structure of the reduced enzyme with the inhibitor oxypurinol. The tightness of the substrates in the active site suggests that the intermediate products must exit the binding pocket to allow first the attack of the C-2, followed by oxidation of the C-8 atom to form the final product uric acid. Structural studies of pterin-6-aldehyde, a potent inhibitor of R. capsulatus XDH, contribute further to the understanding of the relative positioning of inhibitors and substrates in the binding pocket. Steady state kinetics reveal a competitive inhibition pattern with a K-i of 103.57 +/- 18.96 nM for pterin-6-aldehyde.
We present cross-hole P- and S-wave seismic experiments that have been performed along a similar to 100 m long transect for the detailed characterization of a contaminated sedimentary site (Bitterfeld research test site, Germany). We invert the corresponding first break arrival times for the P- and S-wave velocity structure and compare two different strategies to interpret these models in terms of pertinent lithological and geotechnical parameter variations. The first (common) approach is based on directly translating the tomographic velocity models into the parameters of interest (e.g., elastic moduli). The second (zonal) approach first reduces the tomographic parameter information to a limited number of characteristic velocity combinations via k-means cluster analysis. Then, for each zone (cluster) further parameters including uncertainties can be estimated. In the presented case study, Our results indicate that the zonal approach provides an effective means for the integrated interpretation of different co-located data.
Preferential trade agreements pose a big challenge for the multilateral trading system. Throughout the first decade of the twenty-first century, their number has grown significantly. However, these agreements have a range of disadvantages compared with the multilateral regime, for example, in trade facilitation and in dispute settlement. Whereas it will be difficult to stop the further spreading of this wave of preferential agreements, attempts can be made to reduce the negative effects of trade agreements that do, by definition, discriminate against other countries. In this article, a range of potential remedies are discussed, from a moratorium to the better enforcement of World Trade Organization rules on preferential agreements as well as improved monitoring.
The low-productivity South Pacific Gyre (SPG) is Earth's largest oceanic province. Its sediment accumulates extraordinarily slowly (0.1-1 m per million years). This sediment contains a living community that is characterized by very low biomass and very low metabolic activity. At every depth in cored SPG sediment, mean cell abundances are 3 to 4 orders of magnitude lower than at the same depths in all previously explored subseafloor communities. The net rate of respiration by the subseafloor sedimentary community at each SPG site is 1 to 3 orders of magnitude lower than the rates at previously explored sites. Because of the low respiration rates and the thinness of the sediment, interstitial waters are oxic throughout the sediment column in most of this region. Consequently, the sedimentary community of the SPG is predominantly aerobic, unlike previously explored subseafloor communities. Generation of H-2 by radiolysis of water is a significant electron-donor source for this community. The per-cell respiration rates of this community are about 2 orders of magnitude higher (in oxidation/reduction equivalents) than in previously explored anaerobic subseafloor communities. Respiration rates and cell concentrations in subseafloor sediment throughout almost half of the world ocean may approach those in SPG sediment.
Nonlinear force-free field (NLFFF) models are thought to be viable tools for investigating the structure, dynamics, and evolution of the coronae of solar active regions. In a series of NLFFF modeling studies, we have found that NLFFF models are successful in application to analytic test cases, and relatively successful when applied to numerically constructed Sun-like test cases, but they are less successful in application to real solar data. Different NLFFF models have been found to have markedly different field line configurations and to provide widely varying estimates of the magnetic free energy in the coronal volume, when applied to solar data. NLFFF models require consistent, force-free vector magnetic boundary data. However, vector magnetogram observations sampling the photosphere, which is dynamic and contains significant Lorentz and buoyancy forces, do not satisfy this requirement, thus creating several major problems for force-free coronal modeling efforts. In this paper, we discuss NLFFF modeling of NOAA Active Region 10953 using Hinode/SOT-SP, Hinode/XRT, STEREO/SECCHI-EUVI, and SOHO/MDI observations, and in the process illustrate three such issues we judge to be critical to the success of NLFFF modeling: (1) vector magnetic field data covering larger areas are needed so that more electric currents associated with the full active regions of interest are measured, (2) the modeling algorithms need a way to accommodate the various uncertainties in the boundary data, and (3) a more realistic physical model is needed to approximate the photosphere-to-corona interface in order to better transform the forced photospheric magnetograms into adequate approximations of nearly force-free fields at the base of the corona. We make recommendations for future modeling efforts to overcome these as yet unsolved problems.
Rhodococcus fascians is a Gram-positive phytopathogen that induces shooty hyperplasia on its hosts through the secretion of cytokinins. Global transcriptomics using microarrays combined with profiling of primary metabolites on infected Arabidopsis (Arabidopsis thaliana) plants revealed that this actinomycete modulated pathways to convert its host into a niche. The transcript data demonstrated that R. fascians leaves a very characteristic mark on Arabidopsis with a pronounced cytokinin response illustrated by the activation of cytokinin perception, signal transduction, and homeostasis. The microarray data further suggested active suppression of an oxidative burst during the R. fascians pathology, and comparison with publicly available transcript data sets implied a central role for auxin in the prevention of plant defense activation. Gene Ontology categorization of the differentially expressed genes hinted at a significant impact of infection on the primary metabolism of the host, which was confirmed by subsequent metabolite profiling. The much higher levels of sugars and amino acids in infected plants are presumably accessed by the bacteria as carbon and nitrogen sources to support epiphytic and endophytic colonization. Hexoses, accumulating from a significantly increased invertase activity, possibly inhibited the expression of photosynthesis genes and photosynthetic activity in infected leaves. Altogether, these changes are indicative of sink development in symptomatic tissues. The metabolomics data furthermore point to the possible occurrence of secondary signaling during the interaction, which might contribute to symptom development. These data are placed in the context of regulation of bacterial virulence gene expression, suppression of defense, infection phenotype, and niche establishment.
The dimension of a variety V of algebras of a given type was introduced by E. Graczynska and D. Schweigert in [7] as the cardinality of the set of all derived varieties of V which are properly contained in V. In this paper, we characterize all solid varieties of dimensions 0, 1, and 2; prove that the dimension of a variety of finite type is at most N-0; give an example of a variety which has infinite dimension; and show that for every n is an element of N there is a variety with dimension n. Finally, we show that the dimension of a variety is related to the concept of the semantical kernel of a hypersubstitution and apply this connection to calculate the dimension of the class of all algebras of type tau = (n).
An n-ary cooperation is a mapping from a nonempty set A to the nth copower of A. A clone of cooperations is a set of cooperations which is closed under superposition and contains all injections. Coalgebras are pairs consisting of a set and a set of cooperations defined on this set. We define terms for coalgebras, coidentities and cohyperidentities. These concepts will be applied to give a new solution of the completeness problem for clones of cooperations defined on a two-element set and to separate clones of cooperations by coidentities.
Considering the increasing number and complexity of ground-motion prediction equations available for seismic hazard assessment, there is a definite need for an efficient, quantitative, and robust method to select and rank these models for a particular region of interest. In a recent article, Scherbaum et al. (2009) have suggested an information- theoretic approach for this purpose that overcomes several shortcomings of earlier attempts at using data-driven ground- motion prediction equation selection procedures. The results of their theoretical study provides evidence that in addition to observed response spectra, macroseismic intensity data might be useful for model selection and ranking. We present here an applicability study for this approach using response spectra and macroseismic intensities from eight Californian earthquakes. A total of 17 ground-motion prediction equations, from different regions, for response spectra, combined with the equation of Atkinson and Kaka (2007) for macroseismic intensities are tested for their relative performance. The resulting data-driven rankings show that the models that best estimate ground motion in California are, as one would expect, Californian and western U. S. models, while some European models also perform fairly well. Moreover, the model performance appears to be strongly dependent on both distance and frequency. The relative information of intensity versus response spectral data is also explored. The strong correlation we obtain between intensity-based rankings and spectral-based ones demonstrates the great potential of macroseismic intensities data for model selection in the context of seismic hazard assessment.
Process instantiation
(2009)
Although several process modeling languages allow one to specify processes with multiple start elements, the precise semantics of such models are often unclear, both from a pragmatic and from a theoretical point of view. This paper addresses the lack of research on this problem and introduces the CASU framework (from Creation, Activation, subscription, Unsubscription). The contribution of this framework is a systematic description of design alternatives for the specification of instantiation semantics of process modeling languages. We classify six prominent languages by the help of this framework. We validate the relevance of the CASU framework through empirical investigations involving a large set of process models from practice. Our work provides the basis for the design of new correctness criteria as well as for the formalization of Event-driven Process Chains (EPCs) and extension of the Business Process Modeling Notation (BPMN). It complements research such as the workflow patterns.
Interacting services play a key role to realize business process integration among different business partners by means of electronic message exchange. In order to provide seamless integration of these services, the messages exchanged as well as their dependencies must be well-defined. Service choreographies are a means to describe the allowed conversations. This article presents a requirements framework for service choreography languages, along which existing choreography languages are assessed. The requirements framework provides the basis for introducing the language BPEL4Chor, which extends the industry standard WS-BPEL with choreography-specific concepts. A validation is provided and integration with executable service orchestrations is discussed.
Background: A prominent model of semantic processing in modern cognitive psychology proposes that semantic memory originates in everyday life experience with concrete objects such as plants, animals, and tools (Martin Chao, 2001). When the meaning of a concrete content word is being acquired, the learner is confronted with stimuli of various modalities related to the word's meaning. This comes to be stored as sensory knowledge about the object. It is further postulated that there is a conceptual domain remote from the mechanisms of perception, which is often referred to as functional knowledge or verbal semantics. There is a large body of neuropsychological literature trying to establish how much sensory and functional semantics is needed to access a name, and whether the relative contribution of these types of knowledge is the same for all categories of objects. Another controversial issue is whether naming requires access to semantic knowledge, or whether object names can be accessed directly from vision without the intervention of semantics, as is generally accepted for written word naming. Some support for this assumption seems to come from cases of so-called non-optic aphasia, a condition in which patients can name from visual presentation only but not from any other modality of presentation such as auditory, verbal, tactile, etc. In optic aphasia, a condition far better established, naming is possible from all modalities except vision. Aims: The aim of this paper is to draw attention to the first case description of non-optic or negative optic aphasia described by Wolff (1897, 1904). Methods Procedures: The case describes the results of a re-examination of Voit, who was seen by several neurologists in the course of a decade in classical aphasiology. The patient demonstrated anomia in oral but not in written naming of objects in view. Wolff's examination involves extensive testing of semantic processing in several modalities, especially with respect to the status of functional and sensory semantic features Outcomes Results: The re-examination of patient Voit by Wolff in 1897 with new procedures revealed a specific impairment in processing sensory knowledge, while functional knowledge of objects was relatively preserved. This led to a naming impairment in all modalities of presentation except the visual one. Using more refined tasks, Wolff also demonstrated receptive impairments, in contrast to previous researchers who had concluded that the impairment was restricted to oral production. Conclusions: Although Wolff's (1904) case of negative optic aphasia has been almost completely forgotten (but see Bartels Wallesch, 1996), it is astonishingly modern in its conceptual approach and in the central questions it addresses on the mechanisms involved in the process of naming and on the structure of the semantic system. As is usual in classical cases, the methodology may appear less stringent than in most contemporary work, but the approach was brilliant.
A series of copolymers containing oxadiazole and fluorene cromophores was synthesized by polycondensation of a diacid chloride incorporating one diphenylsilane linkage and a mixture of aromatic diamines containing oxadiazole and fluorene moieties. The solubility, thermal behavior, and photoluminescence ability of the thin polymer films were studied and compared with related heterocyclic polymers. These polymers are semicrystalline and form plastic mesophases in the first heating run, which brings about new ordered melted state processing opportunities. They exhibited blue photoluminescence in nanometric films, thus being promising candidates for manufacturing electroluminescent devices.
Di-nor-benzofuran neolignan aldehydes, Delta(7)-3,4-methylenedioxy-3'-methoxy-8',9'-dinor- 4',7-epoxy-8,3'-neolignan-7'-aldehyde (ocophyllal A) 1, Delta(7)-3,4,5,3'-tetramethoxy- 8',9'-dinor-4',7-epoxy-8,3'-neolignan-7'-aldehyde (ocophyllal B) 2, and macrophyllin-type bicyclo[3.2.1]octanoid neolignans (7R, 8R, 3'S, 4'S, 5'R)-Delta(8)'-4'-hydroxy-5'- methoxy-3,4-methylenedioxy-2',3'.4',5'-tetrahydro-2'-oxo-7.3',8.5'-neolignan (ocophyllol A) 3, (7R, 8R, 3'S, 4'S, 5'R)-Delta 8'-4'-hydroxy-3,4,5'-trimethoxy- 2',3',4',5'-tetrahydro-2'-oxo-7.3',8.5'-neolignan (ocophyllol B) 4, (7R, 8R, 3'S, 4'S, 5'R)-Delta(8)'-4'-hydroxy-3,4,5,5'-tetramethoxy- 2',3',4',5'-tetrahydro-2'-oxo-7.3',8.5'-neolignan (ocophyllol C) 5, as well as 2'-epi-guianin 6 and (+)-licarin B 7, were isolated and characterized from leaves of Ocotea macrophylla (Lauraceae). The structures and configuration of these compounds were determined by extensive spectroscopic analyses. Inhibition of platelet activating factor (PAF)-induced aggregation of rabbit platelets were tested with neolignans 1-7. Although compound 6 was the most potent PAF-antagonist, compounds 3-5 showed some activity.
Macrophyllin-type bicyclo[3.2.1]octanoid neolignans from the leaves of Pleurothyrium cinereum
(2009)
Four new macrophyllin-type bicyclo[3.2.1]octanoid neolignans, (7S,8R,3'S,5'R)-Delta(8')- 5,5',3'-trimethoxy-3,4-methylenedioxy-2',3',4',5'-tetrahydro-2',4'-dioxo- 7.3',8.5'-neolignan (cinerin A), 1, (7R,8R,3'S,4'R,5'R)-Delta(8')-4'-hydroxy- 5,5'-dimethoxy-3,4-methylenedioxy-2',3',4',5'-tetrahydro-2'-oxo- 7.3',8.5'-neolignan (cinerin B), 2, (7S,8R,3'R,4'S,5'R)-Delta(8')-4'-hydroxy- 5,5',3'-trimethoxy-3,4-methylenedioxy-2',3',4',5'-tetrahydro-2'-oxo- 7.3',8.5'-neolignan (cinerin C), 3, and (7S,8R,2'RYS,5'R)-Delta(8')-2'-hydroxy- 5,5'-dimethoxy-3,4-methylenedioxy-2',3',4',5'-tetrahydro-4'-oxo- 7.3',8.5'-neolignan (cinerin D). 4, along with the known diterpene kaurenoic acid 5, were isolated from the leaves of Pleurothyrium cinercum. The structures and configuration of these compounds were determined by extensive spectroscopic analysis. Cinerins A-D (1-4) were tested for their inhibition efficacy of platelet activating factor (PAF)- induced aggregation of rabbit platelets. Compound 3 was the most potent PAF antagonist. Compounds 1-5 were tested against Mycobacterium tuberculosis (H(37)Rv strain) using the MABA method. Compound 5 induced 91.3% growth inhibition at 50 mu g mL(-1). Compounds 1-5 showed no significant inhibitory activity against some Gram-positive and Gram-negative bacteria by the agar-well diffusion method.
The anti-inflammatory potential of 26 neolignans (14 of the bicyclooctane-type and 12 of the benzofuran-type), isolated from three Lauraceae species (Pleurothyrium cinereum, Ocotea macrophylla and Nectandra amazonum), was evaluated in vitro through inhibition of COX-1, COX-2, 5-LOX and agonist-induced aggregation of rabbit platelets. Benzofuran neolignans were found to be selective COX-2 inhibitors, whereas bicyclooctane neolignans inhibit selectively the PAF- action as well as COX-1 and 5-LOX. The neolignan 9-nor-7,8-dehydro-isolicarin B 15 and cinerin C 7 were found to be the most potent COX-2 inhibitor and PAF-antagonist, respectively. Nectamazin C 10 exhibited dual 5-LOX/COX-2 inhibition.
We introduce a new mixed finite element for solving the 2- and 3-dimensional wave equations and equations of incompressible flow. The element, which we refer to as P1(D)-P2, uses discontinuous piecewise linear functions for velocity and continuous piecewise quadratic functions for pressure. The aim of introducing the mixed formulation is to produce a new flexible element choice for triangular and tetrahedral meshes which satisfies the LBB stability condition and hence has no spurious zero-energy modes. The advantage of this particular element choice is that the mass matrix for velocity is block diagonal so it can be trivially inverted; it also allows the order of the pressure to be increased to quadratic whilst maintaining LBB stability which has benefits in geophysical applications with Coriolis forces. We give a normal mode analysis of the semi-discrete wave equation in one dimension which shows that the element pair is stable, and demonstrate that the element is stable with numerical integrations of the wave equation in two dimensions, an analysis of the resultant discrete Laplace operator in two and three dimensions on various meshes which shows that the element pair does not have any spurious modes. We provide convergence tests for the element pair which confirm that the element is stable since the convergence rate of the numerical solution is quadratic.
Genome-scale metabolic networks which have been automatically derived through sequence comparison techniques are necessarily incomplete. We propose a strategy that incorporates genomic sequence data and metabolite profiles into modeling approaches to arrive at improved gene annotations and more complete genome-scale metabolic networks. The core of our strategy is an algorithm that computes minimal sets of reactions by which a draft network has to be extended in order to be consistent with experimental observations. A particular strength of our approach is that alternative possibilities are suggested and thus experimentally testable hypotheses are produced. We carefully evaluate our strategy on the well-studied metabolic network of Escherichia coli, demonstrating how the predictions can be improved by incorporating sequence data. Subsequently, we apply our method to the recently sequenced green alga Chlamydomonas reinhardtii. We suggest specific genes in the genome of Chlamydomonas which are the strongest candidates for coding the responsible enzymes.
Motivation: Full-length DNA and protein sequences that span the entire length of a gene are ideally used for multiple sequence alignments (MSAs) and the subsequent inference of their relationships. Frequently, however, MSAs contain a substantial amount of missing data. For example, expressed sequence tags (ESTs), which are partial sequences of expressed genes, are the predominant source of sequence data for many organisms. The patterns of missing data typical for EST-derived alignments greatly compromise the accuracy of estimated phylogenies. Results: We present a statistical method for inferring phylogenetic trees from EST-based incomplete MSA data. We propose a class of hierarchical models for modeling pairwise distances between the sequences, and develop a fully Bayesian approach for estimation of the model parameters. Once the distance matrix is estimated, the phylogenetic tree may be constructed by applying neighbor-joining (or any other algorithm of choice). We also show that maximizing the marginal likelihood from the Bayesian approach yields similar results to a pro. le likelihood estimation. The proposed methods are illustrated using simulated protein families, for which the true phylogeny is known, and one real protein family.
We report on the structural and electronic interface formation between ITO (indium-tin-oxide) and prototypical organic small molecular semiconductors, i.e., CuPc (copper phthalocyanine) and alpha-NPD (N,N'-di(naphtalen-1-yl)- N,N'-diphenyl-benzidine). In particular, the effects of in situ oxygen plasma pretreatment of the ITO surface on interface properties are examined in detail: Organic layer-thickness dependent Kelvin probe measurements revealed a good alignment of the ITO work function and the highest occupied electronic level of the organic material in all samples. In contrast, the electrical properties of hole-only and bipolar organic diodes depend strongly on the treatment of ITO prior to organic deposition. This dependence is more pronounced for diodes made of polycrystalline CuPc than for those of amorphous alpha-NPD layers. X-ray diffraction and atomic force microscopic (AFM) investigations of CuPc nucleation and growth evidenced a more pronounced texture of the polycrystalline film structure on the ITO substrate that was oxygen plasma treated prior to organic layer deposition. These findings suggest that the anisotropic electrical properties of CuPc crystallites, and their orientation with respect to the substrate, strongly affect the charge carrier injection and transport properties at the anode interface.