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An approach is presented to modify the work function of solution-processed sol-gel derived zinc oxide (ZnO) over an exceptionally wide range of more than 2.3 eV. This approach relies on the formation of dense and homogeneous self-assembled monolayers based on phosphonic acids with different dipole moments. This allows us to apply ZnO as charge selective bottom electrodes in either regular or inverted solar cell structures, using poly(3-hexylthiophene): phenyl-C71-butyric acid methyl ester as the active layer. These devices compete with or even surpass the performance of the reference on indium tin oxide/poly(3,4-ethylenedioxythiophene) polystyrene sulfonate. Our findings highlight the potential of properly modified ZnO as electron or hole extracting electrodes in hybrid optoelectronic devices. (C) 2015 AIP Publishing LLC.
Young Genes out of the Male: An Insight from Evolutionary Age Analysis of the Pollen Transcriptome
(2015)
The birth of new genes in genomes is an important evolutionary event. Several studies reveal that new genes in animals tend to be preferentially expressed in male reproductive tissues such as testis (Betran et al., 2002; Begun et al., 2007; Dubruille et al., 2012), and thus an "out of testis' hypothesis for the emergence of new genes has been proposed (Vinckenbosch et al., 2006; Kaessmann, 2010). However, such phenomena have not been examined in plant species. Here, by employing a phylostratigraphic method, we dated the origin of protein-coding genes in rice and Arabidopsis thaliana and observed a number of young genes in both species. These young genes tend to encode short extracellular proteins, which may be involved in rapid evolving processes, such as reproductive barriers, species specification, and antimicrobial processes. Further analysis of transcriptome age indexes across different tissues revealed that male reproductive cells express a phylogenetically younger transcriptome than other plant tissues. Compared with sporophytic tissues, the young transcriptomes of the male gametophyte displayed greater complexity and diversity, which included a higher ratio of anti-sense and inter-genic transcripts, reflecting a pervasive transcription state that facilitated the emergence of new genes. Here, we propose that pollen may act as an "innovation incubator' for the birth of de novo genes. With cases of male-biased expression of young genes reported in animals, the "new genes out of the male' model revealed a common evolutionary force that drives reproductive barriers, species specification, and the upgrading of defensive mechanisms against pathogens.
The structure of bulk liquid water was recently probed by x-ray scattering below the temperature limit of homogeneous nucleation (T-H) of similar to 232 K [J. A. Sellberg et al., Nature 510, 381-384 (2014)]. Here, we utilize a similar approach to study the structure of bulk liquid water below T-H using oxygen K-edge x-ray emission spectroscopy (XES). Based on previous XES experiments [T. Tokushima et al., Chem. Phys. Lett. 460, 387-400 (2008)] at higher temperatures, we expected the ratio of the 1b(1)' and 1b(1)" peaks associated with the lone-pair orbital in water to change strongly upon deep supercooling as the coordination of the hydrogen (H-) bonds becomes tetrahedral. In contrast, we observed only minor changes in the lone-pair spectral region, challenging an interpretation in terms of two interconverting species. A number of alternative hypotheses to explain the results are put forward and discussed. Although the spectra can be explained by various contributions from these hypotheses, we here emphasize the interpretation that the line shape of each component changes dramatically when approaching lower temperatures, where, in particular, the peak assigned to the proposed disordered component would become more symmetrical as vibrational interference becomes more important. (C) 2015 AIP Publishing LLC.
There is a wealth of evidence showing that increasing the distance between an argument and its head leads to more processing effort, namely, locality effects: these are usually associated with constraints in working memory (DLT: Gibson, 2000: activation-based model: Lewis and Vasishth, 2005). In SOV languages, however, the opposite effect has been found: antilocality (see discussion in Levy et al., 2013). Antilocality effects can be explained by the expectation based approach as proposed by Levy (2008) or by the activation-based model of sentence processing as proposed by Lewis and Vasishth (2005). We report an eye-tracking and a self-paced reading study with sentences in Spanish together with measures of individual differences to examine the distinction between expectation- and memory based accounts, and within memory-based accounts the further distinction between DLT and the activation-based model. The experiments show that (i) antilocality effects as predicted by the expectation account appear only for high-capacity readers; (ii) increasing dependency length by interposing material that modifies the head of the dependency (the verb) produces stronger facilitation than increasing dependency length with material that does not modify the head; this is in agreement with the activation-based model but not with the expectation account; and (iii) a possible outcome of memory load on low-capacity readers is the increase in regressive saccades (locality effects as predicted by memory-based accounts) or, surprisingly, a speedup in the self-paced reading task; the latter consistent with good-enough parsing (Ferreira et al., 2002). In sum, the study suggests that individual differences in working memory capacity play a role in dependency resolution, and that some of the aspects of dependency resolution can be best explained with the activation-based model together with a prediction component.
There is a wealth of evidence showing that increasing the distance between an argument and its head leads to more processing effort, namely, locality effects; these are usually associated with constraints in working memory (DLT: Gibson, 2000; activation-based model: Lewis and Vasishth, 2005). In SOV languages, however, the opposite effect has been found: antilocality (see discussion in Levy et al., 2013). Antilocality effects can be explained by the expectation-based approach as proposed by Levy (2008) or by the activation-based model of sentence processing as proposed by Lewis and Vasishth (2005). We report an eye-tracking and a self-paced reading study with sentences in Spanish together with measures of individual differences to examine the distinction between expectation- and memory-based accounts, and within memory-based accounts the further distinction between DLT and the activation-based model. The experiments show that (i) antilocality effects as predicted by the expectation account appear only for high-capacity readers; (ii) increasing dependency length by interposing material that modifies the head of the dependency (the verb) produces stronger facilitation than increasing dependency length with material that does not modify the head; this is in agreement with the activation-based model but not with the expectation account; and (iii) a possible outcome of memory load on low-capacity readers is the increase in regressive saccades (locality effects as predicted by memory-based accounts) or, surprisingly, a speedup in the self-paced reading task; the latter consistent with good-enough parsing (Ferreira et al., 2002). In sum, the study suggests that individual differences in working memory capacity play a role in dependency resolution, and that some of the aspects of dependency resolution can be best explained with the activation-based model together with a prediction component.
Context. Wolf-Rayet (WR) stars have a severe impact on their environments owing to their strong ionizing radiation fields and powerful stellar winds. Since these winds are considered to be driven by radiation pressure, it is theoretically expected that the degree of the wind mass-loss depends on the initial metallicity of WR stars.
Aims. Following our comprehensive studies of WR stars in the Milky Way, M31, and the LMC, we derive stellar parameters and mass-loss rates for all seven putatively single WN stars known in the SMC. Based on these data, we discuss the impact of a low-metallicity environment on the mass loss and evolution of WR stars.
Methods. The quantitative analysis of the WN stars is performed with the Potsdam Wolf-Rayet (PoWR) model atmosphere code. The physical properties of our program stars are obtained from fitting synthetic spectra to multi-band observations.
Results. In all SMC WN stars, a considerable surface hydrogen abundance is detectable. The majority of these objects have stellar temperatures exceeding 75 kK, while their luminosities range from 10(5.5) to 10(6.1) L-circle dot. The WN stars in the SMC exhibit on average lower mass-loss rates and weaker winds than their counterparts in the Milky Way, M31, and the LMC.
Conclusions. By comparing the mass-loss rates derived for WN stars in different Local Group galaxies, we conclude that a clear dependence of the wind mass-loss on the initial metallicity is evident, supporting the current paradigm that WR winds are driven by radiation. A metallicity effect on the evolution of massive stars is obvious from the HRD positions of the SMC WN stars at high temperatures and high luminosities. Standard evolution tracks are not able to reproduce these parameters and the observed surface hydrogen abundances. Homogeneous evolution might provide a better explanation for their evolutionary past.
Germany experienced a unique rise in the level of self-employment in the first two decades following unification. Applying the nonlinear Blinder-Oaxaca decomposition technique, we find that the main factors driving these changes in the overall level of self-employment are demographic developments, the shift towards service sector employment and a larger share of population holding a tertiary degree. While these factors explain most of the development in self-employment with employees and the overall level of self-employment in West Germany, their explanatory power is much lower for the stronger increase in solo self-employment and in self-employment in former socialist East Germany.
Co-doping of the MOF 3∞[Zn(2-methylimidazolate-4-amide-5-imidate)] (IFP-1 = Imidazolate Framework Potsdam-1) with luminescent Eu3+ and Tb3+ ions presents an approach to utilize the porosity of the MOF for the intercalation of luminescence centers and for tuning of the chromaticity to the emission of white light of the quality of a three color emitter. Organic based fluorescence processes of the MOF backbone as well as metal based luminescence of the dopants are combined to one homogenous single source emitter while retaining the MOF's porosity. The lanthanide ions Eu3+ and Tb3+ were doped in situ into IFP-1 upon formation of the MOF by intercalation into the micropores of the growing framework without a structure directing effect. Furthermore, the color point is temperature sensitive, so that a cold white light with a higher blue content is observed at 77 K and a warmer white light at room temperature (RT) due to the reduction of the organic emission at higher temperatures. The study further illustrates the dependence of the amount of luminescent ions on porosity and sorption properties of the MOF and proves the intercalation of luminescence centers into the pore system by low-temperature site selective photoluminescence spectroscopy, SEM and EDX. It also covers an investigation of the border of homogenous uptake within the MOF pores and the formation of secondary phases of lanthanide formates on the surface of the MOF. Crossing the border from a homogenous co-doping to a two-phase composite system can be beneficially used to adjust the character and warmth of the white light. This study also describes two-color emitters of the formula Ln@IFP-1a–d (Ln: Eu, Tb) by doping with just one lanthanide Eu3+ or Tb3+.
How is reading development reflected in eye-movement measures? How does the perceptual span change during the initial years of reading instruction? Does parafoveal processing require competence in basic word-decoding processes? We report data from the first cross-sectional measurement of the perceptual span of German beginning readers (n = 139), collected in the context of the large longitudinal PIER (Potsdamer Intrapersonale Entwicklungsrisiken/Potsdam study of intra-personal developmental risk factors) study of intrapersonal developmental risk factors. Using the moving-window paradigm, eye movements of three groups of students (Grades 1-3) were measured with gaze-contingent presentation of a variable amount of text around fixation. Reading rate increased from Grades 1-3, with smaller increases for higher grades. Perceptual-span results showed the expected main effects of grade and window size: fixation durations and refixation probability decreased with grade and window size, whereas reading rate and saccade length increased. Critically, for reading rate, first-fixation duration, saccade length and refixation probability, there were significant interactions of grade and window size that were mainly based on the contrast between Grades 3 and 2 rather than Grades 2 and 1. Taken together, development of the perceptual span only really takes off between Grades 2 and 3, suggesting that efficient parafoveal processing presupposes that basic processes of reading have been mastered.
When local poverty is more important than your income: Mental health in minorities in inner cities
(2015)
The Paleogene latitude of the Lhasa terrane (southern Tibet) can constrain the age of the onset of the India-Asia collision. Estimates for this latitude, however, vary from 5 degrees N to 30 degrees N, and thus, here, we reassess the geochronology and paleomagnetism of Paleogene volcanic rocks from the Linzizong Group in the Linzhou basin. The lower and upper parts of the section previously yielded particularly conflicting ages and paleolatitudes. We report consistent Ar-40/Ar-39 and U-Pb zircon dates of similar to 52Ma for the upper Linzizong, and Ar-40/Ar-39 dates (similar to 51Ma) from the lower Linzizong are significantly younger than U-Pb zircon dates (64-63Ma), suggesting that the lower Linzizong was thermally and/or chemically reset. Paleomagnetic results from 24 sites in lower Linzizong confirm a low apparent paleolatitude of similar to 5 degrees N, compared to the upper part (similar to 20 degrees N) and to underlying Cretaceous strata (similar to 20 degrees N). Detailed rock magnetic analyses, end-member modeling of magnetic components, and petrography from the lower and upper Linzizong indicate widespread secondary hematite in the lower Linzizong, whereas hematite is rare in upper Linzizong. Volcanic rocks of the lower Linzizong have been hydrothermally chemically remagnetized, whereas the upper Linzizong retains a primary remanence. We suggest that remagnetization was induced by acquisition of chemical and thermoviscous remanent magnetizations such that the shallow inclinations are an artifact of a tilt correction applied to a secondary remanence in lower Linzizong. We estimate that the Paleogene latitude of Lhasa terrane was 204 degrees N, consistent with previous results suggesting that India-Asia collision likely took place by similar to 52Ma at similar to 20 degrees N.
With less than two decades of activity, research on melt inclusions (MI) in crystals from rocks that have undergone crustal anatexis - migmatites and granulites - is a recent addition to crustal petrology and geochemistry. Studies on this subject started with glassy inclusions in anatectic crustal enclaves in lavas, and then progressed to regionally metamorphosed and partially melted crustal rocks, where melt inclusions are normally crystallized into a cryptocrystalline aggregate (nanogranitoid).
Since the first paper on melt inclusions in the granulites of the Kerala Khondalite Belt in 2009, reported and studied occurrences are already a few tens. Melt inclusions in migmatites and granulites show many analogies with their more common and long studied counterparts in igneous rocks, but also display very important differences and peculiarities, which are the subject of this review. Microstructurally, melt inclusions in anatectic rocks are small, commonly 10 mu m in diameter, and their main mineral host is peritectic garnet, although several other hosts have been observed. Inclusion contents vary from glass in enclaves that were cooled very rapidly from supersolidus temperatures, to completely crystallized material in slowly cooled regional migmatites. The chemical composition of the inclusions can be analyzed combining several techniques (SEM, EMP, NanoSIMS, LA-ICP-MS), but in the case of crystallized inclusions the experimental remelting under confining pressure in a piston cylinder is a prerequisite. The melt is generally granitic and peraluminous, although granodioritic to trondhjemitic compositions have also been found.
Being mostly primary in origin, inclusions attest for the growth of their peritectic host in the presence of melt. As a consequence, the inclusions have the unique ability of preserving information on the composition of primary anatectic crustal melts, before they undergo any of the common following changes in their way to produce crustal magmas. For these peculiar features, melt inclusions in migmatites and granulites, largely overlooked so far, have the potential to become a fundamental tool for the study of crustal melting, crustal differentiation, and even the generation of the continental crust. (C) 2015 The Authors. Published by Elsevier B.V.
In cultures of unicellular algae, features of single cells, such as cellular volume and starch content, are thought to be the result of carefully balanced growth and division processes. Single-cell analyses of synchronized photoautotrophic cultures of the unicellular alga Chlamydomonas reinhardtii reveal, however, that the cellular volume and starch content are only weakly correlated. Likewise, other cell parameters, e.g., the chlorophyll content per cell, are only weakly correlated with cell size. We derive the cell size distributions at the beginning of each synchronization cycle considering growth, timing of cell division and daughter cell release, and the uneven division of cell volume. Furthermore, we investigate the link between cell volume growth and starch accumulation. This work presents evidence that, under the experimental conditions of light-dark synchronized cultures, the weak correlation between both cell features is a result of a cumulative process rather than due to asymmetric partition of biomolecules during cell division. This cumulative process necessarily limits cellular similarities within a synchronized cell population.
Climate change will alter the forces of predation and competition in temperate ectotherm food webs. This may increase local extinction rates, change the fate of invasions and impede species reintroductions into communities. Invasion success could be modulated by traits (e.g., defenses) and adaptations to climate. We studied how different temperatures affect the time until extinction of species, using bitrophic and tritrophic planktonic food webs to evaluate the relative importance of predatory overexploitation and competitive exclusion, at 15 and 25 A degrees C. In addition, we tested how inclusion of a subtropical as opposed to a temperate strain in this model food web affects times until extinction. Further, we studied the invasion success of the temperate rotifer Brachionus calyciflorus into the planktonic food web at 15 and 25 A degrees C on five consecutive introduction dates, during which the relative forces of predation and competition differed. A higher temperature dramatically shortened times until extinction of all herbivore species due to carnivorous overexploitation in tritrophic systems. Surprisingly, warming did not increase rates of competitive exclusion among the tested herbivore species in bitrophic communities. Including a subtropical herbivore strain reduced top-down control by the carnivore at high temperature. Invasion attempts of temperate B. calyciflorus into the food web always succeeded at 15 A degrees C, but consistently failed at 25 A degrees C due to voracious overexploitation by the carnivore. Pre-induction of defenses (spines) in B. calyciflorus before the invasion attempt did not change its invasion success at the high temperature. We conclude that high temperatures may promote local extinctions in temperate ectotherms and reduce their chances of successful recovery.
Background: Sub-Saharan Africa is facing a double burden of malnutrition: vitamin A deficiency (VAD) prevails, whereas the nutrition-related chronic conditions type 2 diabetes (T2D) and hypertension are emerging. Serum retinol a VAD marker increases in kidney disease and decreases in inflammation, which can partly be attributed to alterations in the vitamin A transport proteins retinol-binding protein 4 (RBP4) and prealbumin. Kidney dysfunction and inflammation commonly accompany T2D and hypertension.
Objective: Among urban Ghanaians, we investigated the associations of T2D and hypertension with serum retinol as well as the importance of kidney function and inflammation in this regard.
Design: A hospital-based, case-control study in individuals for risk factors of T2D, hypertension, or both was conducted in Kumasi, Ghana (328 controls, 197 with T2D, 354 with hypertension, and 340 with T2D plus hypertension). In 1219 blood samples, serum retinol, RBP4, and prealbumin were measured. Urinary albumin and estimated glomerular filtration rate (eGFR) defined kidney function. C-reactive protein (CRP) >5 mg/L indicated inflammation. We identified associations of T2D and hypertension with retinol by linear regression and calculated the contribution of RBP4, prealbumin, urinary albumin, eGFR, and CRP to these associations as the percentages of the explained variance of retinol.
Results: VAD (retinol <1.05 mu mol/L) was present in 10% of this predominantly female, middle-aged, overweight, and deprived population. Hypertension, but not T2D, was positively associated with retinol (beta: 0.12; 95% CI: 0.08, 0,17), adjusted for age, sex, socioeconomic factors, anthropometric measurements, and lifestyle. In addition to RBP4 (72%) and prealbumin (22%), the effect of increased retinol on individuals with hypertension was mainly attributed to impaired kidney function (eGFR: 30%; urinary albumin: 5%) but not to inflammation.
Conclusions: In patients with hypertension, VAD might be underestimated because of increased serum retinol in the context of kidney dysfunction. Thus, the interpretation of serum retinol in sub-Saharan Africa should account for hypertension status.
This study investigates the effect of foveal load (i.e., processing difficulty of currently fixated words) on parafoveal information processing. Contrary to the commonly accepted view that high foveal load leads to reduced parafoveal processing efficiency, results of the present study showed that increasing foveal visual (but not linguistic) processing load actually increased the amount of parafoveal information acquired, presumably due to the fact that longer fixation duration on the pretarget word provided more time for parafoveal processing of the target word. It is therefore proposed in the present study that foveal linguistic processing load is not the only factor that determines parafoveal processing; preview time (afforded by foveal word visual processing load) may jointly influence parafoveal processing. (C) 2015 Elsevier Ltd. All rights reserved.
It is well established in language acquisition research that monolingual children and adult second language learners misinterpret sentences with the universal quantifier every and make quantifier-spreading errors that are attributed to a preference for a match in number between two sets of objects. The present Visual World eye-tracking study tested bilingual heritage Russian-English adults and investigated how they interpret of sentences like Every alligator lies in a bathtub in both languages. Participants performed a sentence-picture verification task while their eye movements were recorded. Pictures showed three pairs of alligators in bathtubs and two extra objects: elephants (Control condition), bathtubs (Overexhaustive condition), or alligators (Underexhaustive condition). Monolingual adults performed at ceiling in all conditions. Heritage language (HL) adults made 20% q-spreading errors, but only in the Overexhaustive condition, and when they made an error they spent more time looking at the two extra bathtubs during the Verb region. We attribute q-spreading in HL speakers to cognitive overload caused by the necessity to integrate conflicting sources of information, i.e. the spoken sentences in their weaker, heritage, language and attention-demanding visual context, that differed with respect to referential salience.
Optical properties of modified diamondoids have been studied theoretically using vibrationally resolved electronic absorption, emission and resonance Raman spectra. A time-dependent correlation function approach has been used for electronic two-state models, comprising a ground state (g) and a bright, excited state (e), the latter determined from linear-response, time-dependent density functional theory (TD-DFT). The harmonic and Condon approximations were adopted. In most cases origin shifts, frequency alteration and Duschinsky rotation in excited states were considered. For other cases where no excited state geometry optimization and normal mode analysis were possible or desired, a short-time approximation was used. The optical properties and spectra have been computed for (i) a set of recently synthesized sp(2)/sp(3) hybrid species with CQC double-bond connected saturated diamondoid subunits, (ii) functionalized (mostly by thiol or thione groups) diamondoids and (iii) urotropine and other C-substituted diamondoids. The ultimate goal is to tailor optical and electronic features of diamondoids by electronic blending, functionalization and substitution, based on a molecular-level understanding of the ongoing photophysics.
Optical properties of modified diamondoids have been studied theoretically using vibrationally resolved electronic absorption, emission and resonance Raman spectra. A time-dependent correlation function approach has been used for electronic two-state models, comprising a ground state (g) and a bright, excited state (e), the latter determined from linear-response, time-dependent density functional theory (TD-DFT). The harmonic and Condon approximations were adopted. In most cases origin shifts, frequency alteration and Duschinsky rotation in excited states were considered. For other cases where no excited state geometry optimization and normal mode analysis were possible or desired, a short-time approximation was used. The optical properties and spectra have been computed for (i) a set of recently synthesized sp2/sp3 hybrid species with C[double bond, length as m-dash]C double-bond connected saturated diamondoid subunits, (ii) functionalized (mostly by thiol or thione groups) diamondoids and (iii) urotropine and other C-substituted diamondoids. The ultimate goal is to tailor optical and electronic features of diamondoids by electronic blending, functionalization and substitution, based on a molecular-level understanding of the ongoing photophysics.
We study the vertical extent of propeller structures in Saturn's rings (i) by extending the model of Spahn and Sremcevic (Spahn, F., Sremcevic, M. [2000]. Astron. Astrophys., 358, 368-372) to include the vertical direction and (ii) by performing N-body box simulations of a perturbing moonlet embedded into the rings. We find that the gravitational interaction of ring particles with a non-inclined moonlet does not induce considerable vertical excursions of ring particles, but causes a considerable thermal motion in the ring plane. We expect ring particle collisions to partly convert the lateral induced thermal motion into vertical excursions of ring particles in the course of a quasi-thermalization. The N-body box simulations lead to maximal propeller heights of about 0.6-0.8 Hill radii of the embedded perturbing moonlet. Moonlet sizes estimated by this relation are in good agreement with size estimates from radial propeller scalings for the propellers Bleriot and Earhart. For large propellers, the extended hydrodynamical propeller model predicts an exponential propeller height relaxation, confirmed by N-body box simulations of non-self gravitating ring particles. Exponential cooling constants, calculated from the hydrodynamical propeller model agree fairly well with values from fits to the tail of the azimuthal height decay of the N-body box simulations. From exponential cooling constants, determined from shadows cast by the propeller Earhart and imaged by the Cassini spacecraft, we estimate collision frequencies of about 6 collisions per particle per orbit in the propeller gap region and about 11 collisions per particle per orbit in the propeller wake region. (C) 2015 Elsevier Inc. All rights reserved.
Individual great earthquakes are posited to release the elastic strain energy that has accumulated over centuries by the gradual movement of tectonic plates(1,2). However, knowledge of plate deformation during a complete seismic cycle-two successive great earthquakes and the intervening interseismic period-remains incomplete(3). A complete seismic cycle began in south-central Chile in 1835 with an earthquake of about magnitude 8.5 (refs 4,5) and ended in 2010 with a magnitude 8.8 earthquake(6). During the first earthquake, an uplift of Isla Santa Maria by 2.4 to 3m was documented(4,5). In the second earthquake, the island was uplifted(7) by 1.8 m. Here we use nautical surveys made in 1804, after the earthquake in 1835 and in 1886, together with modern echo sounder surveys and GPS measurements made immediately before and after the 2010 earthquake, to quantify vertical deformation through the complete seismic cycle. We find that in the period between the two earthquakes, Isla Santa Maria subsided by about 1.4 m. We simulate the patterns of vertical deformation with a finite-element model and find that they agree broadly with predictions from elastic rebound theory(2). However, comparison with geomorphic and geologic records of millennial coastline emergence(8,9) reveal that 10-20% of the vertical uplift could be permanent.
We present results from VERITAS observations of the BL Lac object PG 1553+113 spanning the years 2010, 2011, and 2012. The time-averaged spectrum, measured between 160 and 560 GeV, is well described by a power law with a spectral index of 4.33 +/- 0.09. The time-averaged integral flux above 200 GeV measured for this period was (1.69 +/- 0.06) x 10(-11) photons cm(-2) s(-1), corresponding to 6.9% of the Crab Nebula flux. We also present the combined gamma-ray spectrum from the Fermi Large Area Telescope and VERITAS covering an energy range from 100 MeV to 560 GeV. The data are well fit by a power law with an exponential cutoff at 101.9 +/- 3.2 GeV. The origin of the cutoff could be intrinsic to PG 1553+113 or be due to the gamma-ray opacity of our universe through pair production off the extragalactic background light (EBL). Given lower limits to the redshift of z > 0.395 based on optical/UV observations of PG 1553+113, the cutoff would be dominated by EBL absorption. Conversely, the small statistical uncertainties of the VERITAS energy spectrum have allowed us to provide a robust upper limit on the redshift of PG 1553+113 of z <= 0.62. A strongly elevated mean flux of (2.50 +/- 0.14) x10(-11) photons cm(-2) s(-1) (10.3% of the Crab Nebula flux) was observed during 2012, with the daily flux reaching as high as (4.44 +/- 0.71) x10(-11) photons cm(-2) s(-1) (18.3% of the Crab Nebula flux) on MJD 56048. The light curve measured during the 2012 observing season is marginally inconsistent with a steady flux, giving a chi(2) probability for a steady flux of 0.03%.
Siberian arctic vegetation and lake water communities, known for their temperature dependence, are expected to be particularly impacted by recent climate change and high warming rates. However, decadal information on the nature and strength of recent vegetation change and its time lag to climate signals are rare. In this study, we present a Pb-210/Cs-137 dated pollen and Pediastrum species record from a unnamed lake in the south of the Taymyr peninsula covering the period from AD 1706 to 2011. Thirty-nine palynomorphs and 10 morphotypes of Pediastrum species were studied to assess changes in vegetation and lake conditions as probable responses to climate change. We compared the pollen record with Pediastrum species, which we consider to be important proxies of climate changes. Three pollen assemblage zones characterised by Betula nana, Alnus viridis and Larix gmelinii (1706-1808); herbs such as Cyperaceae, Artemisia or Senecio (1808-1879), and higher abundance of Larix pollen (1955-2011) are visible. Also, three Pediastrum assemblage zones show changes of aquatic conditions: higher abundances of Pediastrum boryanum var. brevicorne (1706-1802); medium abundances of P. kawraiskyi and P. integrum (1802-1840 and 1920-1980), indicating cooler conditions while less eutrophic conditions are indicated by P. boryanum, and a mainly balanced composition with only small changes of cold- and warm-adapted Pediastrum species (1965-2011). In general, compositional Pediastrum species turnover is slightly higher than that indicated by pollen data (0.54 vs 0.34 SD), but both are only minor for this treeline location. In conclusion, the relevance of differentiation of Pediastrum species is promising and can give further insights into the relationship between lakes and their surrounding vegetation transferred onto climatic conditions.
Effective recognition of enzymatically active tetrameric acetylcholinesterase (AChE) is accomplished by a hybrid nanofilm composed of a propidium-terminated self-assembled monolayer (Prop-SAM) which binds AChE via its peripheral anionic site (PAS) and an ultrathin electrosynthesized molecularly imprinted polymer (MIP) cover layer of a novel carboxylate-modified derivative of 3,4-propylenedioxythiophene. The rebinding of the AChE to the MIP/Prop-SAM nanofilm covered electrode is detected by measuring in situ the enzymatic activity. The oxidative current of the released thiocholine is dependent on the AChE concentration from approximate to 0.04 x 10(-6) to 0.4 x 10(-6)m. An imprinting factor of 9.9 is obtained for the hybrid MIP, which is among the best values reported for protein imprinting. The dissociation constant characterizing the strength of the MIP-AChE binding is 4.2 x 10(-7)m indicating the dominant role of the PAS-Prop-SAM interaction, while the benefit of the MIP nanofilm covering the Prop-SAM layer is the effective suppression of the cross-reactivity toward competing proteins as compared with the Prop-SAM. The threefold selectivity gain provided by i) the shape-specific MIP filter, ii) the propidium-SAM, iii) signal generation only by the AChE bound to the nanofilm shows promise for assessing AChE activity levels in cerebrospinal fluid.
Information structure has been one of the central topics of recent linguistic research. This review discusses a wide range of current approaches with particular reference to African languages, as these have been playing a crucial role in advancing our knowledge about the diversity of and recurring patterns in both meaning and form of information structural notions. We focus on cross-linguistic functional frameworks, the investigation of prosody, formal syntactic theories, and relevant effects of semantic interpretation. Information structure is a thriving research domain that promises to yield important advances in our general understanding of human language.
Many chemical reactions in biological cells occur at very low concentrations of constituent molecules. Thus, transcriptional gene-regulation is often controlled by poorly expressed transcription-factors, such as E. coli lac repressor with few tens of copies. Here we study the effects of inherent concentration fluctuations of substrate-molecules on the seminal Michaelis-Menten scheme of biochemical reactions. We present a universal correction to the Michaelis-Menten equation for the reaction-rates. The relevance and validity of this correction for enzymatic reactions and intracellular gene-regulation is demonstrated. Our analytical theory and simulation results confirm that the proposed variance-corrected Michaelis-Menten equation predicts the rate of reactions with remarkable accuracy even in the presence of large non-equilibrium concentration fluctuations. The major advantage of our approach is that it involves only the mean and variance of the substrate-molecule concentration. Our theory is therefore accessible to experiments and not specific to the exact source of the concentration fluctuations.
Many chemical reactions in biological cells occur at very low concentrations of constituent molecules. Thus, transcriptional gene-regulation is often controlled by poorly expressed transcription-factors, such as E.coli lac repressor with few tens of copies. Here we study the effects of inherent concentration fluctuations of substrate-molecules on the seminal Michaelis-Menten scheme of biochemical reactions. We present a universal correction to the Michaelis-Menten equation for the reaction-rates. The relevance and validity of this correction for enzymatic reactions and intracellular gene-regulation is demonstrated. Our analytical theory and simulation results confirm that the proposed variance-corrected Michaelis-Menten equation predicts the rate of reactions with remarkable accuracy even in the presence of large non-equilibrium concentration fluctuations. The major advantage of our approach is that it involves only the mean and variance of the substrate-molecule concentration. Our theory is therefore accessible to experiments and not specific to the exact source of the concentration fluctuations.
Brain activation stability is crucial to understanding attention lapses. EEG methods could provide excellent markers to assess neuronal response variability with respect to temporal (intertrial coherence) and spatial variability (topographic consistency) as well as variations in activation intensity (low frequency variability of single trial global field power).
We calculated intertrial coherence, topographic consistency and low frequency amplitude variability during target P300 in a continuous performance test in 263 15-year-olds from a cohort with psychosocial and biological risk factors.
Topographic consistency and low frequency amplitude variability predicted reaction time fluctuations (RTSD) in a linear model. Higher RTSD was only associated with higher psychosocial adversity in the presence of the homozygous 6R-10R dopamine transporter haplotype.
We propose that topographic variability of single trial P300 reflects noise as well as variability in evoked cortical activation patterns. Dopaminergic neuromodulation interacted with environmental and biological risk factors to predict behavioural reaction time variability. (C) 2015 Elsevier B.V. All rights reserved.
Validation of two accelerometers to determine mechanical loading of physical activities in children
(2015)
The purpose of this study was to assess the validity of accelerometers using force plates (i.e., ground reaction force (GRF)) during the performance of different tasks of daily physical activity in children. Thirteen children (10.1 (range 5.4-15.7)years, 3 girls) wore two accelerometers (ActiGraph GT3X+ (ACT), GENEA (GEN)) at the hip that provide raw acceleration signals at 100Hz. Participants completed different tasks (walking, jogging, running, landings from boxes of different height, rope skipping, dancing) on a force plate. GRF was collected for one step per trial (10 trials) for ambulatory movements and for all landings (10 trials), rope skips and dance procedures. Accelerometer outputs as peak loading (g) per activity were averaged. ANOVA, correlation analyses and Bland-Altman plots were computed to determine validity of accelerometers using GRF. There was a main effect of task with increasing acceleration values in tasks with increasing locomotion speed and landing height (P<0.001). Data from ACT and GEN correlated with GRF (r=0.90 and 0.89, respectively) and between each other (r=0.98), but both accelerometers consistently overestimated GRF. The new generation of accelerometer models that allow raw signal detection are reasonably accurate to measure impact loading of bone in children, although they systematically overestimate GRF.
Vacuum space charge induced kinetic energy shifts of O 1s and Ru 3d core levels in femtosecond soft X-ray photoemission spectra (PES) have been studied at a free electron laser (FEL) for an oxygen layer on Ru(0001). We fully reproduced the measurements by simulating the in-vacuum expansion of the photoelectrons and demonstrate the space charge contribution of the high-order harmonics in the FEL beam. Employing the same analysis for 400 nm pump-X-ray probe PES, we can disentangle the delay dependent Ru 3d energy shifts into effects induced by space charge and by lattice heating from the femtosecond pump pulse. (C) 2015 Author(s).
Reporter gene assays are widely used for the assessment of transcription factor activation following xenobiotic exposure of cells. A critical issue with such assays is the possibility of interference of test compounds with the test system, for example, by direct inhibition of the reporter enzyme. Here we show that the pyrrolizidine alkaloid heliotrine interferes with reporter signals derived from GAL4-based nuclear receptor transactivation assays by a mechanism independent of luciferase enzyme inhibition. These data highlight the necessity to conduct proper control experiments in order to avoid perturbation of reporter assays by test chemicals. (C) 2015 Elsevier Inc. All rights reserved.
In this work we extract the microphysical properties of aerosols for a collection of measurement cases with low volume depolarization ratio originating from fire sources captured by the Raman lidar located at the National Institute of Optoelectronics (INOE) in Bucharest. Our algorithm was tested not only for pure smoke but also for mixed smoke and urban aerosols of variable age and growth. Applying a sensitivity analysis on initial parameter settings of our retrieval code was proved vital for producing semi-automatized retrievals with a hybrid regularization method developed at the Institute of Mathematics of Potsdam University. A direct quantitative comparison of the retrieved microphysical properties with measurements from a Compact Time of Flight Aerosol Mass Spectrometer (CToF-AMS) is used to validate our algorithm. Microphysical retrievals performed with sun photometer data are also used to explore our results. Focusing on the fine mode we observed remarkable similarities between the retrieved size distribution and the one measured by the AMS. More complicated atmospheric structures and the factor of absorption appear to depend more on particle radius being subject to variation. A good correlation was found between the aerosol effective radius and particle age, using the ratio of lidar ratios (LR: aerosol extinction to backscatter ratios) as an indicator for the latter. Finally, the dependence on relative humidity of aerosol effective radii measured on the ground and within the layers aloft show similar patterns. (C) 2015 Elsevier Inc. All rights reserved.
Depression is the most prevalent psychiatric disorder in the general population. Despite a large demand for efficient treatment options, the majority of older depressed adults does not receive adequate treatment: Additional low-threshold treatments are needed for this age group. Over the past two decades, a growing number of randomized controlled trials (RCT) have been conducted, testing the efficacy of physical exercise in the alleviation of depression in older adults. This meta-analysis systematically reviews and evaluates these studies; some subanalyses testing specific effects of different types of exercise and settings are also performed. In order to be included, exercise programs of the RCTs had to fulfill the criteria of exercise according to the American College of Sports Medicine, including a sample mean age of 60 or above and an increased level of depressive symptoms. Eighteen trials with 1,063 participants fulfilled our inclusion criteria. A comparison of the posttreatment depression scores between the exercise and control groups revealed a moderate effect size in favor of the exercise groups (standardized mean difference (SMD) of –0.68, p < .001). The effect was comparable to the results achieved when only the eleven trials with low risk of bias were included (SMD = –0.63, p < .001). The subanalyses showed significant effects for all types of exercise and for supervised interventions. The results of this meta-analysis suggest that physical exercise may serve as a feasible, additional intervention to fight depression in older adults. However, because of small sample sizes of the majority of individual trials and high statistical heterogeneity, results must be interpreted carefully.
We have characterized ultraviolet (UV) photon-induced DNA strand break processes by determination of absolute cross sections for photoabsorption and for sequence-specific DNA single strand breakage induced by photons in an energy range from 6.50 to 8.94 eV. These represent the lowest-energy photons able to induce DNA strand breaks. Oligonudeotide targets are immobilized on a UV transparent substrate in controlled quantities through attachment to DNA origami templates. Photon-induced dissociation of single DNA strands is visualized and quantified using atomic force microscopy. The obtained quantum yields for strand breakage vary between 0.06 and 0.5, indicating highly efficient DNA strand breakage by UV photons, which is clearly dependent on the photon energy. Above the ionization threshold strand breakage becomes clearly the dominant form of DNA radiation damage, which is then also dependent on the nucleotide sequence.
We extend the scope of European palaeogenomics by sequencing the genomes of Late Upper Palaeolithic (13,300 years old, 1.4-fold coverage) and Mesolithic (9,700 years old, 15.4-fold) males from western Georgia in the Caucasus and a Late Upper Palaeolithic (13,700 years old, 9.5-fold) male from Switzerland. While we detect Late Palaeolithic-Mesolithic genomic continuity in both regions, we find that Caucasus hunter-gatherers (CHG) belong to a distinct ancient clade that split from western hunter-gatherers similar to 45 kya, shortly after the expansion of anatomically modern humans into Europe and from the ancestors of Neolithic farmers similar to 25 kya, around the Last Glacial Maximum. CHG genomes significantly contributed to the Yamnaya steppe herders who migrated into Europe similar to 3,000 BC, supporting a formative Caucasus influence on this important Early Bronze age culture. CHG left their imprint on modern populations from the Caucasus and also central and south Asia possibly marking the arrival of Indo-Aryan languages.
We present the first image of the Madeira upper crustal structure, using ambient seismic noise tomography. 16 months of ambient noise, recorded in a dense network of 26 seismometers deployed across Madeira, allowed reconstructing Rayleigh wave Green's functions between receivers. Dispersion analysis was performed in the short period band from 1.0 to 4.0 s. Group velocity measurements were regionalized to obtain 20 tomographic images, with a lateral resolution of 2.0 km in central Madeira. Afterwards, the dispersion curves, extracted from each cell of the 2D group velocity maps, were inverted as a function of depth to obtain a 3D shear wave velocity model of the upper crust, from the surface to a depth of 2.0 km. The obtained 3D velocity model reveals features throughout the island that correlates well with surface geology and island evolution. (C) 2015 Elsevier B.V. All rights reserved.
By overcoming the diffraction limit in light microscopy, super-resolution techniques, such as stimulated emission depletion (STED) microscopy, are experiencing an increasing impact on life sciences. High costs and technically demanding setups, however, may still hinder a wider distribution of this innovation in biomedical research laboratories. As far-field microscopy is the most widely employed microscopy modality in the life sciences, upgrading already existing systems seems to be an attractive option for achieving diffraction-unlimited fluorescence microscopy in a cost-effective manner. Here, we demonstrate the successful upgrade of a commercial time-resolved confocal fluorescence microscope to an easy-to-align STED microscope in the single-beam path layout, previously proposed as "easy-STED", achieving lateral resolution <lambda/10 corresponding to a five-fold improvement over a confocal modality. For this purpose, both the excitation and depletion laser beams pass through a commercially available segmented phase plate that creates the STED-doughnut light distribution in the focal plane, while leaving the excitation beam unaltered when implemented into the joint beam path. Diffraction-unlimited imaging of 20 nm-sized fluorescent beads as reference were achieved with the wavelength combination of 635 nm excitation and 766 nm depletion. To evaluate the STED performance in biological systems, we compared the popular phalloidin-coupled fluorescent dyes Atto647N and Abberior STAR635 by labeling F-actin filaments in vitro as well as through immunofluorescence recordings of microtubules in a complex epithelial tissue. Here, we applied a recently proposed deconvolution approach and showed that images obtained from time-gated pulsed STED microscopy may benefit concerning the signal-to-background ratio, from the joint deconvolution of sub-images with different spatial information which were extracted from offline time gating.
Upconversion NaYF4:Yb:Er nanoparticles co-doped with Gd3+ and Nd3+ for thermometry on the nanoscale
(2015)
In the present work, the upconversion luminescence properties of oleic acid capped NaYF4:Gd3+:Yb3+:Er3+ upconversion nanoparticles (UCNP) with pure β crystal phase and Nd3+ ions as an additional sensitizer were studied in the temperature range of 288 K < T < 328 K. The results of this study showed that the complex interplay of different mechanisms and effects, causing the special temperature behavior of the UCNP can be developed into thermometry on the nanoscale, e.g. to be applied in biological systems on a cellular level. The performance was improved by the use of Nd3+ as an additional dopant utilizing the cascade sensitization mechanism in tri-doped UCNP.
Upconversion NaYF4:Yb:Er nanoparticles co-doped with Gd3+ and Nd3+ for thermometry on the nanoscale
(2015)
In the present work, the upconversion luminescence properties of oleic acid capped NaYF4:Gd3+:Yb3+:Er3+ upconversion nanoparticles (UCNP) with pure beta crystal phase and Nd3+ ions as an additional sensitizer were studied in the temperature range of 288 K < T < 328 K. The results of this study showed that the complex interplay of different mechanisms and effects, causing the special temperature behavior of the UCNP can be developed into thermometry on the nanoscale, e.g. to be applied in biological systems on a cellular level. The performance was improved by the use of Nd3+ as an additional dopant utilizing the cascade sensitization mechanism in tri-doped UCNP.
The temperature-dependent upconversion luminescence of NaYF4:Yb:Er nanoparticles (UCNP) containing different contents of Gd3+ as additional dopant was characterized. The UCNP were synthesized in a hydrothermal synthesis and stabilized with citrate in order to transfer them to the water phase. Basic characterization was carried out using TEM and DLS to determine the average size of the UCNP. The XRD technique was used to investigate the crystal lattice of the UCNP. It was found that due to the presence of Gd3+, an alteration of the lattice phase from a to beta was induced which was also reflected in the observed upconversion luminescence properties of the UCNP. A detailed analysis of the upconversion luminescence spectraespecially at ultralow temperaturesrevealed the different effects of phonon coupling between the host lattice and the sensitizer (Yb3+) as well as the activator (Er3+). Furthermore, the upconversion luminescence intensity reached a maximum between 15 and 250 K depending on Gd3+ content. In comparison to the very complex temperature behavior of the upconversion luminescence in the temperature range <273 K, the luminescence intensity ratio of H-2(11/2)-> I-4(15/2) to S-4(3/2)-> I-4(15/2) (R = G1/G2) in a higher temperature range can be described by an Arrhenius-type equation.
Manganese (Mn) is an essential micronutrient for development and function of the nervous system. Deficiencies in Mn transport have been implicated in the pathogenesis of Huntington's disease (HD), an autosomal dominant neurodegenerative disorder characterized by loss of medium spiny neurons of the striatum. Brain Mn levels are highest in striatum and other basal ganglia structures, the most sensitive brain regions to Mn neurotoxicity. Mouse models of HD exhibit decreased striatal Mn accumulation and HD striatal neuron models are resistant to Mn cytotoxicity. We hypothesized that the observed modulation of Mn cellular transport is associated with compensatory metabolic responses to HD pathology. Here we use an untargeted metabolomics approach by performing ultraperformance liquid chromatography-ion mobility-mass spectrometry (UPLC-IM-MS) on control and HD immortalized mouse striatal neurons to identify metabolic disruptions under three Mn exposure conditions, low (vehicle), moderate (non-cytotoxic) and high (cytotoxic). Our analysis revealed lower metabolite levels of pantothenic acid, and glutathione (GSH) in HD striatal cells relative to control cells. HD striatal cells also exhibited lower abundance and impaired induction of isobutyryl carnitine in response to increasing Mn exposure. In addition, we observed induction of metabolites in the pentose shunt pathway in HD striatal cells after high Mn exposure. These findings provide metabolic evidence of an interaction between the HD genotype and biologically relevant levels of Mn in a striatal cell model with known HD by Mn exposure interactions. The metabolic phenotypes detected support existing hypotheses that changes in energetic processes underlie the pathobiology of both HD and Mn neurotoxicity.
The architecture of coastal sequences in tectonically-active regions results mostly from a combination of sea-level and land-level changes. The objective of this study is to unravel these signals by combining sequence stratigraphy and sedimentology of near-shore sedimentary sequences in wave-built terraces. We focus on Santa Maria Island at the south-central Chile margin, which hosts excellent exposures of coastal sediments from Marine Isotope Stage 3. A novel method based on statistical analysis of grain-size distributions coupled with fades descriptions provided a detailed account of transgressive-regressive cycles. Radiocarbon ages from paleosols constrain the chronology between >53 and similar to 31 cal ka BP. Because the influence of glaciations can be neglected, we calculated relative sea-level curves by tying the onset of deposition on a bedrock abrasion platform to a global sea-level curve. The observed depositional cycles match those predicted for uplift rates between 1.2 and 1.8 m/ka. The studied sedimentary units represent depositional cycles that resulted in reoccupation events of an existing marine terrace. Our study demonstrates wave-built marine terrace deposits along clastic shorelines in temperate regions can be used to distinguish between tectonic uplift and climate-induced sea-level changes.