bluuebunny/crossref_metadata_2025 huggingface dataset:
Warum in einer Kindertagesstätte arbeiten?
Authors: Mischo Christoph , Wahl Stefan , Hendler Jessica , Strohmer Janina
Published: July 2012

Zusammenfassung: In dieser Studie wurden Faktoren untersucht, die die Entscheidung für eine Ausbildung bzw. für ein Studium mit dem Ziel einer späteren Tätigkeit in Kindertageseinrichtungen beeinflussen. Bei insgesamt 1233 angehenden ErzieherInnen an Fachschulen und Frühpädagogik-Studierenden an Hochschulen wurden bei Erst- und Viertsemestern mittels latenter Klassenanalysen zwei unterschiedliche Entscheidungstypen für die ErzieherInnen-Ausbildung bzw. ein Frühpädagogik-Studium identifiziert. In beiden Kohorten wurden über 70 % der Personen einem «sicheren» Entscheidungstyp, annähernd 30 % einem «unsicheren» Entscheidungstyp zugeordnet. Als Prädiktoren für die Zugehörigkeit zu den Typen erwiesen sich vor allem intrinsische Tätigkeitsanreize und Kompetenzüberzeugungen. Die Personen der beiden Entscheidungstypen unterschieden sich außerdem in der ausbildungs- bzw. studienbezogenen Lernzielorientierung und Arbeitsvermeidung. Die Implikationen dieser Ergebnisse für die Ausbildung und Rekrutierung frühpädagogischer Fachkräfte werden diskutiert.
Treatment in Nursing Home versus Hospital for Patients with Behavioral and Psychological Symptoms of Dementia
Authors: Hval Stein-Arne , Midtbø Kristiansen Kari , Lorentzen Bernhard , Fagerstrøm Lisbeth , Tanum Lars
Published: July 2012

Introduction: This article is concerned with the optimal treatment of behavioral and psychological symptoms present in patients with dementia. This pilot study compares the benefits of an ambulant treatment intervention in nursing homes to hospital admission. Material and Methods: Patients referred for hospital admission were randomized to either hospital admission or ambulant treatment intervention in their nursing home. Registration of behavioral and psychological symptoms of dementia (BPSD) together with the caregiver’s distress were assessed at T1, T2, and T3 using the Neuropsychiatric Inventory (NPI). Results: Both treatment groups showed a statistically significant reduction in BPSD, and there was no significant difference between the groups in total score of NPI. NPI-reported carer distress was reduced in both groups, and this was statistically significant for the intervention group.
Dynamical downscaling of ECMWF Ensemble seasonal forecasts over East Africa with RegCM3
Authors: Diro G. T. , Tompkins A. M. , Bi X.
Published: July 2012

Dynamical downscaling of ECMWF ERA‐interim reanalysis and an ensemble of May‐start ECMWF seasonal hindcasts is performed with ICTP's regional climate model (RegCM3) over the horn of Africa for a ten year period. Using ERA‐interim ‘perfect boundary’ conditions the regional model reproduced both the spatial and interannual variability of the region's rainfall and improved the global model's reproduction of year to year rainfall variability, capturing the teleconnection between ENSO and the region's precipitation pattern well. The ensembles of ECMWF seasonal hindcasts and the respective downscaled RegCM3 hindcast suite were then validated in terms of the seasonal climate and deterministic and probabilistic skill scores at a one to four month lead time. Both RegCM3 and ECMWF hindcasts reproduce the spatial and temporal rainfall variability well, but overestimate the mean and variability over the Arabian peninsula and misrepresent the teleconnection between ENSO and precipitation over the western Indian Ocean. The positive bias over the Arabian peninsula in RegCM3 and the teleconnection error between ENSO and precipitation anomalies over the western Indian Ocean are due to the propagation of errors from the driving GCMs to the regional model. Nevertheless, the probabilistic assessment (ROCS and RPSS) indicated that both ECMWF and RegCM3 have significant skill suggesting the potential utility of dynamical forecasts over the region. Comparing the skill of ECMWF and RegCM3 probabilistic hindcasts, ECMWF generally performs better on grid point by grid point comparison and at homogeneous zones over Ethiopia but RegCM3 outperforms when aggregated on a country scale and when compared against high resolution rain gauge data set.
Constraints on the frontal crustal structure of a continental collision from an integrated geophysical research: The central‐western Betic Cordillera (SW Spain)
Authors: Ruiz‐Constán A. , Pedrera A. , Galindo‐Zaldívar J. , Pous J. , Arzate J. , Roldán‐García F. J. , Marin‐Lechado C. , Anahnah F.
Published: July 2012

Mélange rocks outcrop widely in the central and western frontal sectors of the Betic Cordillera, as in many other collisional orogens where they form part of the accretionary wedges. Extrusion of Triassic plastic clays and evaporites was favored by the progressive accretion of the Betic External Zones, mixing rocks of different provenance and forming a synorogenic frontal mélange unit. MT data coupled with gravity data are a valid combined methodology to characterize the geometry of these mélange units, since the characterization of plastic rocks geometry is usually uncertain using seismic techniques. The results correlate well with known geological features (sedimentary basins, calcareous ranges, evaporitic rocks) and reveal the deep geometry. A resistive body, slightly dipping toward the SE, points to the continuity of the Iberian Massif below the Guadalquivir basin (2°) and the External Zones (6–8°). To the south, gravity models show the Iberian continental crust subducting below the Internal Zones with a roughly 20–35° slope. The main conductive bodies are related to the location of evaporitic rocks involved in the frontal mélange. They overlie the Iberian Massif and, southwards, the frontal Jurassic and Cretaceous limestone sequences of the External and Median Subbetics. In this setting, thick plastic rock units placed above the foreland could act as a lubricant facilitating continental subduction, and being progressively accreted toward a frontal mélange.
Protein-SIP enables time-resolved analysis of the carbon flux in a sulfate-reducing, benzene-degrading microbial consortium
Authors: Taubert Martin , Vogt Carsten , Wubet Tesfaye , Kleinsteuber Sabine , Tarkka Mika T , Harms Hauke , Buscot François , Richnow Hans-Hermann , von Bergen Martin , Seifert Jana
Published: July 2012

Benzene is a major contaminant in various environments, but the mechanisms behind its biodegradation under strictly anoxic conditions are not yet entirely clear. Here we analyzed a benzene-degrading, sulfate-reducing enrichment culture originating from a benzene-contaminated aquifer by a metagenome-based functional metaproteomic approach, using protein-based stable isotope probing (protein-SIP). The time-resolved, quantitative analysis of carbon fluxes within the community supplied with either 13C-labeled benzene or 13C-labeled carbonate yielded different functional groups of organisms, with their peptides showing specific time dependencies of 13C relative isotope abundance indicating different carbon utilization. Through a detailed analysis of the mass spectrometric (MS) data, it was possible to quantify the utilization of the initial carbon source and the metabolic intermediates. The functional groups were affiliated to Clostridiales, Deltaproteobacteria and Bacteroidetes/Chlorobi. The Clostridiales-related organisms were involved in benzene degradation, putatively by fermentation, and additionally used significant amounts of carbonate as a carbon source. The other groups of organisms were found to perform diverse functions, with Deltaproteobacteria degrading fermentation products and Bacteroidetes/Chlorobi being putative scavengers feeding on dead cells. A functional classification of identified proteins supported this allocation and gave further insights into the metabolic pathways and the interactions between the community members. This example shows how protein-SIP can be applied to obtain temporal and phylogenetic information about functional interdependencies within microbial communities.
Exciton transport in thin-film cyanine dye J-aggregates
Authors: Valleau Stéphanie , Saikin Semion K. , Yung Man-Hong , Guzik Alán Aspuru
Published: July 2012

We present a theoretical model for the study of exciton dynamics in J-aggregated monolayers of fluorescent dyes. The excitonic evolution is described by a Monte-Carlo wave function approach which allows for a unified description of the quantum (ballistic) and classical (diffusive) propagation of an exciton on a lattice in different parameter regimes. The transition between the ballistic and diffusive regime is controlled by static and dynamic disorder. As an example, the model is applied to three cyanine dye J-aggregates: TC, TDBC, and U3. Each of the molecule-specific structure and excitation parameters are estimated using time-dependent density functional theory. The exciton diffusion coefficients are calculated and analyzed for different degrees of film disorder and are correlated to the physical properties and the structural arrangement of molecules in the aggregates. Further, exciton transport is anisotropic and dependent on the initial exciton energy. The upper-bound estimation of the exciton diffusion length in the TDBC thin-film J-aggregate is of the order of hundreds of nanometers, which is in good qualitative agreement with the diffusion length estimated from experiments.
Accounting for uncertainty in the analysis of overlap layer mean velocity models
Authors: Oliver Todd A. , Moser Robert D.
Published: July 2012

When assessing the veracity of mathematical models, it is important to consider the uncertainties in the data used for the assessment. In this paper, we study the impact of data uncertainties on the analysis of overlap layer models for the mean velocity in wall-bounded turbulent flows. Specifically, the tools of Bayesian statistics are used to calibrate and compare six competing models of the mean velocity profile, including multiple logarithmic and power law forms, using velocity profile measurements from a zero-pressure-gradient turbulent boundary layer and fully developed turbulent pipe flow. The calibration problem is formulated as a Bayesian update of the joint probability density function for the calibration parameters, which are treated as random variables to characterize incomplete knowledge about their values. This probabilistic formulation provides a natural treatment of uncertainty and gives insight into the quality of the fit, features that are not easily obtained in deterministic calibration procedures. The model comparison also relies on a Bayesian update. In particular, the relative probabilities of the competing models are updated using the calibration data. The resulting posterior probabilities quantify the relative plausibility of the competing models given the data. For the boundary layer, results are shown for five subsets of the turbulent boundary layer data due to Österlund, including different Reynolds number and wall distance ranges, and multiple assumptions regarding the magnitude of the uncertainty in the velocity measurements. For most choices, multiple models have relatively high posterior probability, indicating that it is difficult to distinguish between the models. For the most inclusive data sets—i.e., the largest ranges of Reynolds number and wall distance—the first-order logarithmic law due to Buschmann and Gad-el-Hak is significantly more probable, given the data, than the other models evaluated. For the pipe flow, data from the Princeton Superpipe is analyzed for the region where McKeon et al. find a logarithmic layer (600 ⩽ y+ ⩽ 0.12δ+). As in the boundary layer case, the first-order logarithmic law by Buschmann and Gad-el-Hak is most probable. However, the parameter values required to fit the data are different from those necessary for the boundary layer. Thus, the present analysis confirms the differences between the boundary layer and pipe flow results observed elsewhere in the literature, casting serious doubt on the universality of overlap layer model parameters.
Automatic identification of model reductions for discrete stochastic simulation
Authors: Wu Sheng , Fu Jin , Li Hong , Petzold Linda
Published: July 2012

Multiple time scales in cellular chemical reaction systems present a challenge for the efficiency of stochastic simulation. Numerous model reductions have been proposed to accelerate the simulation of chemically reacting systems by exploiting time scale separation. However, these are often identified and deployed manually, requiring expert knowledge. This is time-consuming, prone to error, and opportunities for model reduction may be missed, particularly for large models. We propose an automatic model analysis algorithm using an adaptively weighted Petri net to dynamically identify opportunities for model reductions for both the stochastic simulation algorithm and tau-leaping simulation, with no requirement of expert knowledge input. Results are presented to demonstrate the utility and effectiveness of this approach.
Uptake of atmospheric molecules by ice nanoparticles: Pickup cross sections
Authors: Lengyel J. , Kočišek J. , Poterya V. , Pysanenko A. , Svrčková P. , Fárník M. , Zaouris D. K. , Fedor J.
Published: July 2012

Uptake of several atmospheric molecules on free ice nanoparticles was investigated. Typical examples were chosen: water, methane, NOx species (NO, NO2), hydrogen halides (HCl, HBr), and volatile organic compounds (CH3OH, CH3CH2OH). The cross sections for pickup of these molecules on ice nanoparticles (H2O)N with the mean size of \documentclass[12pt]{minimal}\begin{document}$\bar{N} \approx 260$\end{document}N¯≈260 (diameter ∼2.3 nm) were measured in a molecular beam experiment. These cross sections were determined from the cluster beam velocity decrease due to the momentum transfer during the pickup process. For water molecules molecular dynamics simulations were performed to learn the details of the pickup process. The experimental results for water are in good agreement with the simulations. The pickup cross sections of ice particles of several nanometers in diameter can be more than 3 times larger than the geometrical cross sections of these particles. This can have significant consequences in modelling of atmospheric ice nanoparticles, e.g., their growth.
On-the-fly ab initio molecular dynamics with multiconfigurational Ehrenfest method
Authors: Saita Kenichiro , Shalashilin Dmitrii V.
Published: July 2012

In this article we report the formalism and first implementation of the ab initio multiconfigurational Ehrenfest (AI-MCE) method for simulation of ultrafast nonadiabatic dynamics, which uses the MOLPRO electronic structure program to calculate the potential energy surfaces on the fly. The approach is tested on the benchmark of the excited ππ* state dynamics of ethylene producing the dynamics which agree with previous simulations by ab initio multiple spawning technique. The AI-MCE seems to be robust, stable and efficient.
Electric field and van der Waals force induced instabilities in thin viscoelastic bilayers
Authors: Bandyopadhyay Dipankar , Dinesh Sankar Reddy P. , Sharma Ashutosh
Published: July 2012

A unified theory is presented for the field-induced spinodal instabilities of thin viscoelastic bilayers composed of the Maxwell fluids or of the soft solids obeying the Kelvin-Voigt model. The analysis includes the different important mechanisms by which a bilayer is rendered unstable: (1) the wetting instability engendered by the excess van der Waals forces in an ultrathin (<100 nm) bilayer (Figure (1a)); (2) the electric field induced instability caused by an external electrostatic field across the bilayer (Figure (1b)); (3) the contact instability caused by the attractive interactions with another surface in the contact proximity of the upper film (Figure (1c)). The key features of the short-, long-, and finite-wavenumber instabilities are compared and contrasted for a host of bilayers having purely viscous, purely elastic, viscoelastic-viscous, and viscoelastic rheological properties. Linear stability analysis shows: (i) controlling mode of instability can shift from one interface to the other, which is accompanied by an abrupt shift in the time and the length scales of the instabilities with the change in the interfacial tensions, relaxation times, and elastic moduli of the films; (ii) purely elastomeric bilayers show a finite wavenumber bifurcation only beyond a critical destabilizing force due to their elastic stiffness; (iii) bilayers with at least one viscous or Maxwell layer show zero elastic-stiffness against the destabilizing influences; (iv) wetting viscoelastic bilayer is unstable only when it is ultrathin and elastically very soft or if one of the layers is purely viscous; (v) Maxwell (elastomer) bilayers show a faster (slower) growth of instability with the increase in relaxation time (elastic modulus).
High-efficiency heterojunction solar cells on crystalline germanium substrates
Authors: Hekmatshoar Bahman , Shahrjerdi Davood , Hopstaken Marinus , Fogel Keith , Sadana Devendra K.
Published: July 2012

We report stand-alone heterojunction (HJ) solar cells with conversion efficiencies of 5.9% and 7.2% on n-type and p-type crystalline germanium (c-Ge) substrates, respectively. The emitter of the HJ solar cells is formed by growing thin layers of highly doped hydrogenated microcrystalline silicon using plasma-enhanced chemical vapor deposition at temperatures close to 200 °C. The conversion efficiencies of the HJ solar cells are well-comparable with conventional devices fabricated at temperatures as high as 600 °C. We also study the surface passivation of c-Ge with hydrogenated amorphous and microcrystalline Si and correlate the passivation quality with the electrical performance of the HJ solar cells.
Spectral encoding of spatial frequency approach for characterization of nanoscale structures
Authors: Alexandrov Sergey A. , Uttam Shikhar , Bista Rajan K. , Staton Kevin , Liu Yang
Published: July 2012

An approach to acquire axial structural information at nanoscale is demonstrated. It is based on spectral encoding of spatial frequency principle to reconstruct the structural information about the axial profile of the three-dimensional (3D) spatial frequency for each image point. This approach overcomes the fundamental limitations of current optical techniques and provides nanoscale accuracy and sensitivity in characterizing axial structures. Numerical simulation and experimental results are presented.
High-resolution imaging in a deep turbid medium based on an ultrasound-switchable fluorescence technique
Authors: Yuan Baohong , Uchiyama Seiichi , Liu Yuan , Nguyen Kytai T. , Alexandrakis George
Published: July 2012

The spatial resolution of fluorescence imaging techniques in deep optically turbid media such as tissues is limited by photon diffusion. To break the diffusion limit and achieve high-resolution and deep-tissue fluorescence imaging, a fundamentally different method was demonstrated based on a concept of ultrasound-switchable fluorescence. The results showed that a small fluorescent tube with a diameter of ∼180 μm at a depth of ∼20 mm in an optical scattering medium (μs′≈3.2  and μa≈0.026 cm−1) can be clearly imaged with a size of ∼260 μm. The depth-to-resolution ratio is shown to be about one order of magnitude better than other deep-tissue fluorescence imaging techniques.
Incident flux angle induced crystal texture transformation in nanostructured molybdenum films
Authors: Chen L. , Lu T.-M. , Wang G.-C.
Published: July 2012

Molybdenum films were observed to undergo a dramatic change in crystal texture orientation when the incident flux angle was varied in an oblique angle sputter deposition on amorphous substrates. Reflection high-energy electron diffraction pole figure and scanning electron microscopy were used to analyze in detail the texture orientation of the films. The normal incident deposition resulted in a fiber texture film with the minimum energy (110) crystal plane parallel to the substrate surface. A (110)[11¯0] biaxial texture was observed for the samples grown with low incident angles of less than 45°, with respect to the surface normal. On the other hand, for an oblique angle deposition of larger than 60°, a (111)[112¯] biaxial texture was observed and appeared to be consistent with a zone T structure where the geometrically fastest growth [001] direction of a crystal plays a dominant role in defining the texture. We argue that a structural transition had occurred when the incident flux was varied from near normal incidence to a large angle.
Self-organized InAs/InGaAsP quantum dot tube lasers
Authors: Bianucci Pablo , Mukherjee Shouvik , Dastjerdi M. Hadi Tavakoli , Poole Philip J. , Mi Zetian
Published: July 2012

We report the achievement of a semiconductor tube laser that can operate in the optical communication wavelength range for applications in the emerging Si-photonics. Such nanoscale devices are fabricated from self-organized InAs/InGaAsP quantum dot nanomembranes through a strain-driven self-rolling mechanism using standard photolithography process. Under continuous wave optical pumping, the devices exhibit an ultralow lasing threshold of ∼1.26 μW at 82 K, with multiple emission wavelengths in the S band of optical communications. The spontaneous emission coupling factor and Purcell factor are estimated to be ∼0.30 and ∼4.8, respectively.
First-principles study of hydrogenated carbon nanotubes: A promising route for bilayer graphene nanoribbons
Authors: Chen Pengcheng , Li Yuanchang , Si Chen , Wu Jian , Ihm Jisoon , Duan Wenhui
Published: July 2012

Using combined density functional theory and nonequilibrium Green’s function techniques, we demonstrate that hydrogenated armchair single-walled carbon nanotubes (H-CNTs) can exhibit electronic, magnetic, and transport properties remarkably similar to zigzag graphene nanoribbons (ZGNRs). Hydrogen atoms break the circumferential periodic boundary condition of CNTs, incising them into two ZGNRs structurally. The staggered stacking ensures these two ZGNRs to be almost decoupled electronically and retain the electronic properties of monolayer ZGNRs. Interestingly, H-CNTs show unique advantages and application prospects over ZGNRs for their bilayer structure and diverse magnetic couplings between spin-polarized edge states.
Effects of Bacillus coagulans ATCC 7050 on growth performance, intestinal morphology, and microflora composition in broiler chickens
Authors: Hung Alex Tsungyu , Lin Shu-Yuan , Yang Tsung-Yu , Chou Chun-Kuang , Liu Hsun-Cheng , Lu Jin-Jenn , Wang Bo , Chen Shi-Yi , Lien Tu-Fa
Published: July 2012

An experiment was conducted to evaluate the effects of Bacillus coagulans ATCC 7050 (B. coagulans) on the performance, intestinal morphology and microflora of broiler chickens. Six-hundred 1-day-old broilers were randomly assigned into five treatment groups with four replicates for 42 days. There were five dietary treatments: negative control, positive control (antibiotics, 200 mg/kg zinc–bacitracin), 0.10, 0.20 and 0.25 g/kg B. coagulans. Dietary B. coagulans improved feed conversion ratio throughout the entire experimental period compared with the negative control (P = 0.02). Dietary B. coagulans significantly increased the number of lactobacilli (P = 0.01) and tended to decrease coliform bacteria (P = 0.06) in the duodenum. Dietary B. coagulans tended to increase villous height (P = 0.08) but had no effect on crypt depth in the jejunum. There were no significant differences (P > 0.05) in serum cholesterol, triglyceride, high density lipoprotein cholesterol and low density lipoprotein cholesterol between groups. In conclusion, the present data indicate that administration of B. coagulans ATCC 7050 improved feed conversion ratio in broiler chickens, possibly via improving the balance of intestinal microflora.
Observation of scalar nuclear spin–spin coupling in van der Waals complexes
Authors: Ledbetter Micah P. , Saielli Giacomo , Bagno Alessandro , Tran Nhan , Romalis Michael V.
Published: July 2012

Scalar couplings between covalently bound nuclear spins are a ubiquitous feature in nuclear magnetic resonance (NMR) experiments, imparting valuable information to NMR spectra regarding molecular structure and conformation. Such couplings arise due to a second-order hyperfine interaction, and, in principle, the same mechanism should lead to scalar couplings between nuclear spins in unbound van der Waals complexes. Here, we report the first observation of scalar couplings between nuclei in van der Waals complexes. Our measurements are performed in a solution of hyperpolarized
129
Xe and pentane, using superconducting quantum interference devices to detect NMR in 10 mG fields, and are in good agreement with calculations based on density functional theory. van der Waals forces play an important role in many physical phenomena. The techniques presented here may provide a new method for probing such interactions.
Bedrock displacements in Greenland manifest ice mass variations, climate cycles and climate change
Authors: Bevis Michael , Wahr John , Khan Shfaqat A. , Madsen Finn Bo , Brown Abel , Willis Michael , Kendrick Eric , Knudsen Per , Box Jason E. , van Dam Tonie , Caccamise Dana J. , Johns Bjorn , Nylen Thomas , Abbott Robin , White Seth , Miner Jeremy , Forsberg Rene , Zhou Hao , Wang Jian , Wilson Terry , Bromwich David , Francis Olivier
Published: July 2012

The Greenland GPS Network (GNET) uses the Global Positioning System (GPS) to measure the displacement of bedrock exposed near the margins of the Greenland ice sheet. The entire network is uplifting in response to past and present-day changes in ice mass. Crustal displacement is largely accounted for by an annual oscillation superimposed on a sustained trend. The oscillation is driven by earth’s elastic response to seasonal variations in ice mass and air mass (i.e., atmospheric pressure). Observed vertical velocities are higher and often much higher than predicted rates of postglacial rebound (PGR), implying that uplift is usually dominated by the solid earth’s instantaneous elastic response to contemporary losses in ice mass rather than PGR. Superimposed on longer-term trends, an anomalous ‘pulse’ of uplift accumulated at many GNET stations during an approximate six-month period in 2010. This anomalous uplift is spatially correlated with the 2010 melting day anomaly.
Structure of follicle-stimulating hormone in complex with the entire ectodomain of its receptor
Authors: Jiang Xuliang , Liu Heli , Chen Xiaoyan , Chen Po-Han , Fischer David , Sriraman Venkataraman , Yu Henry N. , Arkinstall Steve , He Xiaolin
Published: July 2012

FSH, a glycoprotein hormone, and the FSH receptor (FSHR), a G protein-coupled receptor, play central roles in human reproduction. We report the crystal structure of FSH in complex with the entire extracellular domain of FSHR (FSHR
ED
), including the enigmatic hinge region that is responsible for signal specificity. Surprisingly, the hinge region does not form a separate structural unit as widely anticipated but is part of the integral structure of FSHR
ED
. In addition to the known hormone-binding site, FSHR
ED
provides interaction sites with the hormone: a sulfotyrosine (sTyr) site in the hinge region consistent with previous studies and a potential exosite resulting from putative receptor trimerization. Our structure, in comparison to others, suggests FSHR interacts with its ligand in two steps: ligand recruitment followed by sTyr recognition. FSH first binds to the high-affinity hormone-binding subdomain of FSHR and reshapes the ligand conformation to form a sTyr-binding pocket. FSHR then inserts its sTyr (i.e., sulfated Tyr335) into the FSH nascent pocket, eventually leading to receptor activation.
Cell mechanics control rapid transitions between blebs and lamellipodia during migration
Authors: Bergert Martin , Chandradoss Stanley D. , Desai Ravi A. , Paluch Ewa
Published: July 2012

Protrusion formation is an essential step during cell migration. Cells migrating in three-dimensional environments and in vivo can form a wide variety of protrusion types, including actin polymerization-driven lamellipodia, and contractility-driven blebs. The ability to switch between different protrusions has been proposed to facilitate motility in complex environments and to promote cancer dissemination. However, plasticity in protrusion formation has so far mostly been investigated in the context of transitions between amoeboid and mesenchymal migration modes, which involve substantial changes in overall cell morphology. As a result, the minimal requirements of transitions between blebs and lamellipodia, as well as the time scales on which they occur, remain unknown. To address these questions, we investigated protrusion switching during cell migration at the single cell level. Using cells that can be induced to form either blebs or lamellipodia, we systematically assessed the mechanical requirements, as well as the dynamics, of switching between protrusion types. We demonstrate that shifting the balance between actin protrusivity and actomyosin contractility leads to immediate transitions between blebs and lamellipodia in migrating cells. Switching occurred without changes in global cell shape, polarity, or cell adhesion. Furthermore, rapid transitions between blebs and lamellipodia could also be triggered upon changes in substrate adhesion during migration on micropatterned surfaces. Together, our data reveal that the type of protrusion formed by migrating cells can be dynamically controlled independently of overall cell morphology, suggesting that protrusion formation is an autonomous module in the regulatory network that controls the plasticity of cell migration.
Transcriptional consequences of aneuploidy
Authors: Sheltzer Jason M. , Torres Eduardo M. , Dunham Maitreya J. , Amon Angelika
Published: July 2012

Aneuploidy, or an aberrant karyotype, results in developmental disabilities and has been implicated in tumorigenesis. However, the causes of aneuploidy-induced phenotypes and the consequences of aneuploidy on cell physiology remain poorly understood. We have performed a metaanalysis on gene expression data from aneuploid cells in diverse organisms, including yeast, plants, mice, and humans. We found highly related gene expression patterns that are conserved between species: genes that were involved in the response to stress were consistently upregulated, and genes associated with the cell cycle and cell proliferation were downregulated in aneuploid cells. Within species, different aneuploidies induced similar changes in gene expression, independent of the specific chromosomal aberrations. Taken together, our results demonstrate that aneuploidies of different chromosomes and in different organisms impact similar cellular pathways and cause a stereotypical antiproliferative response that must be overcome before transformation.
A model of global citizenship: Antecedents and outcomes
Authors: Reysen Stephen , Katzarska‐Miller Iva
Published: July 2012

As the world becomes increasingly interconnected, exposure to global cultures affords individuals opportunities to develop global identities. In two studies, we examine the antecedents and outcomes of identifying with a superordinate identity—global citizen. Global citizenship is defined as awareness, caring, and embracing cultural diversity while promoting social justice and sustainability, coupled with a sense of responsibility to act. Prior theory and research suggest that being aware of one's connection with others in the world (global awareness) and embedded in settings that value global citizenship (normative environment) lead to greater identification with global citizens. Furthermore, theory and research suggest that when global citizen identity is salient, greater identification is related to adherence to the group's content (i.e., prosocial values and behaviors). Results of the present set of studies showed that global awareness (knowledge and interconnectedness with others) and one's normative environment (friends and family support global citizenship) predicted identification with global citizens, and global citizenship predicted prosocial values of intergroup empathy, valuing diversity, social justice, environmental sustainability, intergroup helping, and a felt responsibility to act for the betterment of the world. The relationship between antecedents (normative environment and global awareness) and outcomes (prosocial values) was mediated by identification with global citizens. We discuss the relationship between the present results and other research findings in psychology, the implications of global citizenship for other academic domains, and future avenues of research. Global citizenship highlights the unique effect of taking a global perspective on a multitude of topics relevant to the psychology of everyday actions, environments, and identity.
Effects of Maternal Growth on Fecundity and Egg Quality of Wild and Captive Atka Mackerel
Authors: McDermott Susanne F. , Cooper Daniel W. , Guthridge Jared L. , Spies Ingrid B. , Canino Mike F. , Woods Pamela , Hillgruber Nicola
Published: July 2012

Trade-offs in energy allocation between growth and reproduction can result in variations in reproductive potential in fish with differing growth patterns. Spawning biomass is often used as a proxy for reproductive potential on the assumption that fecundity is directly proportional to body weight. We examined variations in the reproductive potential of Atka mackerel Pleurogrammus monopterygius by studying the effect of differential growth and condition patterns on fecundity, atresia, and egg energy. Fecundity and egg energy were determined for fish from two geographic areas, Seguam Pass and Amchitka Island, Alaska, and compared with those of fish held in captivity. These Atka mackerel showed distinct differences in growth and condition, with weight at length and length at age being the highest among captive fish, intermediate among fish from Seguam Pass, and lowest among fish from Amchitka Island. Realized fecundity showed that on average captive fish spawned seven batches, fish from Seguam Pass six batches, and fish from Amchitka Island five batches. For wild fish, potential and realized fecundity at length or age was significantly higher at Seguam Pass than at Amchitka Island, whereas the fecundity-at-weight relationship did not differ by area, suggesting that weight is a better predictor of fecundity than length or age. Atresia and batch fecundity by length or weight did not differ by area, suggesting that the variation in fecundity is better explained by the variation in batch number than by batch size. Oocyte dry weight was higher for captive fish than for wild fish, whereas batch order did not significantly affect oocyte dry weight. Increased potential fecundity, realized fecundity, and oocyte quality in Atka mackerel females were strongly related to body size, indicating that growth differences and maternal feeding success impact the fecundity and oocyte quality of Atka mackerel. Therefore, changes in growth and condition patterns need to be taken into account to accurately estimate the reproductive potential of this species.

Received August 21, 2010; accepted March 2, 2011
PI(3,5)P2 sows the seeds of plant growth
Authors: Short Ben
Published: July 2012

Phospholipid directs polarized growth by targeting actin-polymerizing formins to the cortex of plant cells.
Dual effect of heat shock on DNA replication and genome integrity
Authors: Velichko Artem K. , Petrova Nadezhda V. , Kantidze Omar L. , Razin Sergey V.
Published: July 2012

Heat shock (HS) is one of the better-studied exogenous stress factors. However, little is known about its effects on DNA integrity and the DNA replication process. In this study, we show that in G1 and G2 cells, HS induces a countable number of double-stranded breaks (DSBs) in the DNA that are marked by γH2AX. In contrast, in S-phase cells, HS does not induce DSBs but instead causes an arrest or deceleration of the progression of the replication forks in a temperature-dependent manner. This response also provoked phosphorylation of H2AX, which appeared at the sites of replication. Moreover, the phosphorylation of H2AX at or close to the replication fork rescued the fork from total collapse. Collectively our data suggest that in an asynchronous cell culture, HS might affect DNA integrity both directly and via arrest of replication fork progression and that the phosphorylation of H2AX has a protective effect on the arrested replication forks in addition to its known DNA damage signaling function.
Critical role of the first transmembrane domain of Cx26 in regulating oligomerization and function
Authors: Jara Oscar , Acuña Rodrigo , García Isaac E. , Maripillán Jaime , Figueroa Vania , Sáez Juan C. , Araya-Secchi Raúl , Lagos Carlos F. , Pérez-Acle Tomas , Berthoud Viviana M. , Beyer Eric C. , Martínez Agustín D.
Published: July 2012

To identify motifs involved in oligomerization of the gap junction protein Cx26, we studied individual transmembrane (TM) domains and the full-length protein. Using the TOXCAT assay for interactions of isolated TM α-helices, we found that TM1, a Cx26 pore domain, had a strong propensity to homodimerize. We identified amino acids Val-37–Ala-40 (VVAA) as the TM1 motif required for homodimerization. Two deafness-associated Cx26 mutations localized in this region, Cx26V37I and Cx26A40G, differentially affected dimerization. TM1-V37I dimerized only weakly, whereas TM1-A40G did not dimerize. When the full-length mutants were expressed in HeLa cells, both Cx26V37I and Cx26A40G formed oligomers less efficiently than wild-type Cx26. A Cx26 cysteine substitution mutant, Cx26V37C formed dithiothreitol-sensitive dimers. Substitution mutants of Val-37 formed intercellular channels with reduced function, while mutants of Ala-40 did not form functional gap junction channels. Unlike wild-type Cx26, neither Cx26V37I nor Cx26A40G formed functional hemichannels in low extracellular calcium. Thus the VVAA motif of Cx26 is critical for TM1 dimerization, hexamer formation, and channel function. The differential effects of VVAA mutants on hemichannels and gap junction channels imply that inter-TM interactions can differ in unapposed and docked hemichannels. Moreover, Cx26 oligomerization appears dependent on transient TM1 dimerization as an intermediate step.
Phosphorylation of the effector complex HOPS by the vacuolar kinase Yck3p confers Rab nucleotide specificity for vacuole docking and fusion
Authors: Zick Michael , Wickner William
Published: July 2012

The homotypic fusion of yeast vacuoles requires the Rab-family GTPase Ypt7p and its effector complex, homotypic fusion and vacuole protein sorting complex (HOPS). Although the vacuolar kinase Yck3p is required for the sensitivity of vacuole fusion to proteins that regulate the Rab GTPase cycle—Gdi1p (GDP-dissociation inhibitor [GDI]) or Gyp1p/Gyp7p (GTPase-activating protein)—this kinase phosphorylates HOPS rather than Ypt7p. We addressed this puzzle in reconstituted proteoliposome fusion reactions with all-purified components. In the presence of HOPS and Sec17p/Sec18p, there is comparable fusion of 4-SNARE (soluble N-ethylmaleimide–sensitive factor attachment protein receptor) proteoliposomes when they have Ypt7p bearing either GDP or GTP, a striking exception to the rule that only GTP-bound forms of Ras-superfamily GTPases have active conformations. However, the phosphorylation of HOPS by recombinant Yck3p confers a strict requirement for GTP-bound Ypt7p for binding phosphorylated HOPS, for optimal membrane tethering, and for proteoliposome fusion. Added GTPase-activating protein promotes GTP hydrolysis by Ypt7p, and added GDI captures Ypt7p in its GDP-bound state during nucleotide cycling. In either case, the net conversion of Ypt7:GTP to Ypt7:GDP has no effect on HOPS binding or activity but blocks fusion mediated by phosphorylated HOPS. Thus guanine nucleotide specificity of the vacuolar fusion Rab Ypt7p is conferred through downstream posttranslational modification of its effector complex.
Rice Mitogen-Activated Protein Kinase Interactome Analysis Using the Yeast Two-Hybrid System
Authors: Singh Raksha , Lee Mi-Ok , Lee Jae-Eun , Choi Jihyun , Park Ji Hun , Kim Eun Hye , Yoo Ran Hee , Cho Jung-Il , Jeon Jong-Seong , Rakwal Randeep , Agrawal Ganesh Kumar , Moon Jae Sun , Jwa Nam-Soo
Published: July 2012

Mitogen-activated protein kinase (MAPK) cascades support the flow of extracellular signals to intracellular target molecules and ultimately drive a diverse array of physiological functions in cells, tissues, and organisms by interacting with other proteins. Yet, our knowledge of the global physical MAPK interactome in plants remains largely fragmented. Here, we utilized the yeast two-hybrid system and coimmunoprecipitation, pull-down, bimolecular fluorescence complementation, subcellular localization, and kinase assay experiments in the model crop rice (Oryza sativa) to systematically map what is to our knowledge the first plant MAPK-interacting proteins. We identified 80 nonredundant interacting protein pairs (74 nonredundant interactors) for rice MAPKs and elucidated the novel proteome-wide network of MAPK interactors. The established interactome contains four membrane-associated proteins, seven MAP2Ks (for MAPK kinase), four MAPKs, and 59 putative substrates, including 18 transcription factors. Several interactors were also validated by experimental approaches (in vivo and in vitro) and literature survey. Our results highlight the importance of OsMPK1, an ortholog of tobacco (Nicotiana benthamiana) salicyclic acid-induced protein kinase and Arabidopsis (Arabidopsis thaliana) AtMPK6, among the rice MAPKs, as it alone interacts with 41 unique proteins (51.2% of the mapped MAPK interaction network). Additionally, Gene Ontology classification of interacting proteins into 34 functional categories suggested MAPK participation in diverse physiological functions. Together, the results obtained essentially enhance our knowledge of the MAPK-interacting protein network and provide a valuable research resource for developing a nearly complete map of the rice MAPK interactome.
Implications of pleiotrophin in human PC3 prostate cancer cell growth in vivo
Authors: Tsirmoula Sotiria , Dimas Kostas , Hatziapostolou Maria , Lamprou Margarita , Ravazoula Panagiota , Papadimitriou Evangelia
Published: July 2012

Pleiotrophin (PTN) is a heparin‐binding growth factor with diverse functions related to tumor growth, angiogenesis, and metastasis. Pleiotrophin seems to have a significant role in prostate cancer cell growth and to mediate the stimulatory actions of other factors that affect prostate cancer cell functions. However, all studies carried out up to date are in vitro, using different types of human prostate cancer cell lines. The aim of the present work was to study the role of endogenous PTN in human prostate cancer growth in vivo. For this purpose, human prostate cancer PC3 cells were stably transfected with a plasmid vector, bearing the antisense PTN sequence, in order to inhibit PTN expression (AS‐PC3). Migration, apoptosis, and adhesion on osteoblastic cells were measured in vitro. In vivo, PC3 cells were s.c. injected into male NOD/SCID mice, and tumor growth, survival rates, angiogenesis, apoptosis, and the number of metastasis were estimated. Pleiotrophin depletion resulted in a decreased migration capability of AS‐PC3 cells compared with the corresponding mock‐transfected or the non‐transfected PC3 cells, as well as increased apoptosis and decreased adhesiveness to osteoblastic cells in vitro. In prostate cancer NOD/SCID mouse xenografts, PTN depletion significantly suppressed tumor growth and angiogenesis and induced apoptosis of cancer cells. In addition, PTN depletion decreased the number of metastases, providing a survival benefit for the animals bearing AS‐PC3 xenografts. Our data suggest that PTN is implicated in human prostate cancer growth in vivo and could be considered a potential target for the development of new therapeutic approaches for prostate cancer.
Adherence with health regimens of patients on warfarin therapy
Authors: Kääriäinen Maria , Paukama Merja , Kyngäs Helvi
Published: July 2012

Aims and objectives.  To explore adherence with health regimens and factors influencing it of patients on warfarin therapy.

Background.  Adherence to health regimens is a crucial factor for patients on long‐term warfarin therapy. Approximately 50% of patients with chronic conditions have good adherence. This study covers a more extensive perspective on patients’ adherence to warfarin therapy than earlier studies, which focus mainly on adherence to medication.

Design.  A descriptive cross‐sectional design was used.

Methods.  A survey of 139 patients was conducted in 2008. A self‐reported Adherence of people with Chronic Disease Instrument questionnaire was used to assess adherence to health regimens and factors influencing it. Chi‐squared test, Mann–Whitney U‐test and Kruskal–Wallis test were used to analyse the data.

Results.  About half (51%) of the respondents complied well with health regimens, while 74% had good adherence with warfarin therapy. Females had better adherence than males. The highest degree of adherence was reported by patients who had venous thrombosis and whose therapy had lasted from one to three years. Patients who adhered well to warfarin therapy also had good adherence with other health regimens such as diet, exercise, attending international normalised ratio tests and collaboration with health care. There was also a statistically significant difference between adherence to health regimens and motivation and sense of normality.

Conclusions.  Good adherence to health regimens had an impact on good adherence to warfarin therapy. Collaboration with health care professionals, motivation and patients’ sense of normality are crucial factors to improve adherence.

Relevance to clinical practice.  To improve adherence to health regimens, collaboration between patients and health professionals should be strengthened. Furthermore, discussion with patients can aid in understanding problems of motivation and help health care professionals provide support. Tailoring treatment and care as a part of patients’ life helps them gain a sense of normality and improve adherence.
Disentangling invasion processes in a dynamic shipping–boating network
Authors: LACOURSIÈRE‐ROUSSEL ANAÏS , BOCK DAN G. , CRISTESCU MELANIA E. , GUICHARD FRÉDÉRIC , GIRARD PHILIPPE , LEGENDRE PIERRE , McKINDSEY CHRISTOPHER W.
Published: July 2012

The relative importance of multiple vectors to the initial establishment, spread and population dynamics of invasive species remains poorly understood. This study used molecular methods to clarify the roles of commercial shipping and recreational boating in the invasion by the cosmopolitan tunicate, Botryllus schlosseri. We evaluated (i) single vs. multiple introduction scenarios, (ii) the relative importance of shipping and boating to primary introductions, (iii) the interaction between these vectors for spread (i.e. the presence of a shipping‐boating network) and (iv) the role of boating in determining population similarity. Tunicates were sampled from 26 populations along the Nova Scotia, Canada, coast that were exposed to either shipping (i.e. ports) or boating (i.e. marinas) activities. A total of 874 individuals (c. 30 per population) from five ports and 21 marinas was collected and analysed using both mitochondrial cytochrome c oxidase subunit I gene (COI) and 10 nuclear microsatellite markers. The geographical location of multiple hotspot populations indicates that multiple invasions have occurred in Nova Scotia. A loss of genetic diversity from port to marina populations suggests a stronger influence of ships than recreational boats on primary coastal introductions. Population genetic similarity analysis reveals a dependence of marina populations on those that had been previously established in ports. Empirical data on marina connectivity because of boating better explains patterns in population similarities than does natural spread. We conclude that frequent primary introductions arise by ships and that secondary spread occurs gradually thereafter around individual ports, facilitated by recreational boating.