bluuebunny/crossref_metadata_2025 huggingface dataset:
Improved diffusion profiles in back‐contacted back‐junction Si solar cells with an overcompensated boron‐doped emitter
Authors: Reichel Christian , Bivour Martin , Granek Filip , Hermle Martin , Glunz Stefan W.
Published: July 2011

The performance of n‐type back‐contacted back‐junction silicon solar cells where the boron‐doped emitter diffusion on the rear side is locally overcompensated by a phosphorus‐doped base‐type back surface field (BSF) diffusion has been analysed theoretically and experimentally. By overcompensating the emitter diffusion the noncollecting base‐type region can be reduced significantly allowing electrical shading losses to be minimized. It has been found that for solar cells with a lowly doped BSF diffusion the local external quantum efficiency and the short‐circuit current density Jsc could be improved significantly. For reference solar cells with an undiffused gap between emitter and BSF diffusion and a large noncollecting base‐type region, a maximum Jsc of 40.9 mA/cm2 could be achieved and for solar cells with a locally overcompensated boron‐doped emitter diffusion featuring a small noncollecting base‐type region a maximum Jsc of 41.4 mA/cm2 has been measured. The reduction of Jsc losses caused by free carrier absorption (FCA) in highly doped silicon at near‐infrared wavelengths is also shown. Furthermore, theoretical investigations are performed by one‐dimensional device simulations and the influence of highly doped and lowly doped emitter and BSF diffusions on the open‐circuit voltage Voc is presented. For solar cells with a locally overcompensated boron‐doped emitter diffusion Voc could be improved from 629 to 652 mV when lowly‐doped diffusions and thermally grown SiO2 and antireflection plasma enhanced chemical vapour deposited (PECVD) SiNx passivation stacks are applied. For the reference solar cells with an undiffused gap between the lowly doped emitter and BSF diffusions Voc of 693 mV could be achieved for a plasma enhanced atomic layer deposited (PEALD) Al2O3 passivation layer.
A Bayesian growth mixture model to examine maternal hypertension and birth outcomes
Authors: Neelon Brian , Swamy Geeta K. , Burgette Lane F. , Miranda Marie Lynn
Published: July 2011

Maternal hypertension is a major contributor to adverse pregnancy outcomes, including preterm birth (PTB) and low birth weight (LBW). Although several studies have explored the relationship between maternal hypertension and fetal health, few have examined how the longitudinal trajectory of blood pressure, considered over the course of pregnancy, affects birth outcomes. In this paper, we propose a Bayesian growth mixture model to jointly examine the associations between longitudinal blood pressure measurements, PTB, and LBW. The model partitions women into distinct classes characterized by a mean arterial pressure (MAP) curve and joint probabilities of PTB and LBW. Each class contains a unique mixed effects model for MAP with class‐specific regression coefficients and random effect covariances. To account for the strong correlation between PTB and LBW, we introduce a bivariate probit model within each class to capture residual within‐class dependence between PTB and LBW. The model permits the association between PTB and LBW to vary by class, so that for some classes, PTB and LBW may be positively correlated, whereas for others, they may be uncorrelated or negatively correlated. We also allow maternal covariates to influence the class probabilities via a multinomial logit model. For posterior computation, we propose an efficient MCMC algorithm that combines full‐conditional Gibbs and Metropolis steps. We apply our model to a sample of 1027 women enrolled in the Healthy Pregnancy, Healthy Baby Study, a prospective cohort study of host, social, and environmental contributors to disparities in pregnancy outcomes. Copyright © 2011 John Wiley & Sons, Ltd.
Assuring the model evolution of protocol software specifications by regression testing process improvement
Authors: Jiang Bo , Tse T. H. , Grieskamp Wolfgang , Kicillof Nicolas , Cao Yiming , Li Xiang , Chan W. K.
Published: July 2011

Model‐based testing helps test engineers automate their testing tasks so that they are more cost‐effective. When the model is changed because of the evolution of the specification, it is important to maintain the test suites up to date for regression testing. A complete regeneration of the whole test suite from the new model, although inefficient, is still frequently used in the industry, including Microsoft. To handle specification evolution effectively, we propose a test case reusability analysis technique to identify reusable test cases of the original test suite based on graph analysis. We also develop a test suite augmentation technique to generate new test cases to cover the change‐related parts of the new model. The experiment on four large protocol document testing projects shows that our technique can successfully identify a high percentage of reusable test cases and generate low‐redundancy new test cases. When compared with a complete regeneration of the whole test suite, our technique significantly reduces regression testing time while maintaining the stability of requirement coverage over the evolution of requirements specifications. Copyright © 2011 John Wiley & Sons, Ltd.
Specification and Standardization of a Java Trusted Computing API
Authors: Toegl Ronald , Winkler Thomas , Nauman Mohammad , Hong Theodore W.
Published: July 2011

The paradigm of Trusted Computing promises a new approach to improve the security of computer systems. The core functionality, based on a hardware component known as Trusted Platform Module, is integrated into commodity hardware. However, operating system integration and application software support remains limited at present. In particular, for Java, the most widely used platform‐independent computing environment, there is currently no generally accepted Trusted Computing API. In this article, we describe the design of a high‐level API for Trusted Computing. We report on the current state of the Trusted Computing Group's software architecture and on previous approaches targeting Java. We derive our requirements and design goals and describe a novel API design. We report on our transparent approach to standardization in the Java Community Process. The result of this effort is the API we propose in the Java Specification Request 321. In this work, we not only present the design of this new API but also discuss implementation and testing strategies. Copyright © 2011 John Wiley & Sons, Ltd.
Concise Review: Stem Cell Effects in Radiation Risk
Authors: Prise Kevin M. , Saran Anna
Published: July 2011

Stem cells of normal mammalian tissues are defined as nonspecialized cells that have two critical properties: (a) the ability to renew themselves through cell division and (b) the potency to differentiate into other cell types. Therefore, they play a crucial role in development and in tissue homeostasis during adult life. Being long-lived, they can be the targets of environmental carcinogens leading to the accumulation of consecutive genetic changes. Hence, the genome of stem cells must be exceptionally well protected, and several protective mechanisms have evolved to ensure the genetic integrity of the stem cell compartment in any given tissue. Ionizing radiation exposure can disrupt tissue homeostasis both through the induction of cell killing/depletion of radiosensitive stem cells, leading to loss of tissue functionality and by genotoxic damage, increasing overall risk of cancer. We will review the current knowledge about radiation effects in adult stem cells of specific normal tissues, including skin, breast, and brain, examine parallels, as well as differences with cancer stem cells, and discuss the relevance of stem cell effects to radiation risk and radiotherapy.
Textural and Physical Properties of Biorenewable “Waxes” Containing Partial Acylglycerides
Authors: Yao Linxing , Wang Tong
Published: July 2011

Vegetable oil‐based “waxes” are a promising alternative to beeswax and paraffin wax, the usual raw materials for candles and encaustic painting, because they are environmentally friendly, less expensive than beeswax and more biodegradable than paraffin. In this study, wax mixtures of mono‐ (MAG) and diacylglycerides (DAG) of fully hydrogenated vegetable oil were prepared at various ratios and their textural properties were compared to beeswax. Waxes having 30–40% of DAG were softer and more cohesive than those having other proportions of DAG, and their values were the closest to those of beeswax. A wax mixture of 70% MAG and 30% DAG (MDWAX) was then treated with various additives, including free fatty acid, fatty alcohol, hydroxy triacylglycerides (OHWAX), dammar resin, and acetylated monoacylglycerides (AM). The 1:1 (wt.) mixture of MDWAX and AM (referred as 50% AM) had similar plasticity to that of beeswax, and a high textural stability during one‐month storage. The melting and crystallization properties of the wax containing 10% OHWAX and 90% MDWAX had close similarity to those of beeswax. The crystal form in most formulated waxes was β′ as determined by X‐ray diffraction. However, the 50% AM wax had α and β polymorphs in equal proportions and the MDWAX had only β form crystals. The crystallinity of all formulated waxes was lower than those of beeswax and paraffin. Polarized light microscopy images revealed that the microstructures of formulated waxes were different from that of beeswax. For sensory evaluation, the order of the surface buffability was determined as MDWAX+10% Dammar < MDWAX < MDWAX+50% AM < paraffin < beeswax.
Geographical variation in franciscana (Pontoporia blainvillei) external morphology
Authors: Barbato Beatriz H.A. , Secchi Eduardo R. , Di Beneditto Ana Paula M. , Ramos Renata M.A. , Bertozzi Carolina , Marigo Juliana , Bordino Pablo , Kinas Paul G.
Published: July 2011

Four distinct Franciscana Management Areas (FMAs) have been proposed based on several lines of evidence including genotype, phenotype, population response and distribution. To determine if differences in external morphology fit this division, a canonical variate analysis was carried out for males and/or females from FMAs I to IV using up to 14 characters. A total of 78 adult specimens were analysed. More than 90% of the differences between groups were summarized by three canonical variates. Females were larger than males in all areas. Females from FMA IV were of intermediate length between those from FMA I and FMA III and individuals from FMA II were smaller than those from all other areas. Position of dorsal fin and morphology of the anterior body region, differentiate individuals from FMA I and FMA III. Morphological differences found in this study give additional support for the proposed FMAs. Since habitat characteristics and franciscana feeding ecology vary regionally, it is possible that observed morphological differences are due to ecological divergence for niche occupation. The indication of a discontinuous distribution, consistency between genetic and morphological evidence, and a short time genetic divergence, might indicate that franciscanas inhabiting FMA I represent a distinct subspecies.
Population dynamics of the amphioxusBranchiostoma elongatumfrom northern Chile
Authors: Vergara Makarena , Oliva Marcelo E. , Riascos José M.
Published: July 2011

Amphioxi represent the evolutionary link between vertebrates and invertebrates. For this reason, research dealing with these animals has been focused mainly on embryological and anatomical studies. Out of 30 described species, only one,Branchiostoma elongatum, is known to inhabit shallow sandy bottoms along the Humboldt Current System (HCS) of Chile and Peru. The population dynamics ofB. elongatumfrom northern Chile was studied between February 2008 and January 2009, and the results were compared with other species within the genusBranchiostomainhabiting distinct ecosystems. Mean abundance ofB. elongatumwas low (158.6 ind m−2) in comparison with the abundance of other species withinBranchiostoma. Although the gametogenic activity was continuous, a clear spawning event was observed between August and October, which seemingly produced a recruitment pulse during the summer and consequently a simultaneous increase in population density and decrease of mean length during that period. Growth ofB. elongatumwas best fitted to the seasonalized von Bertalanffy growth function (K = 0.45 year−1and L∞= 64.6 mm), with faster growth during summer–autumn. Growth performance (Ф′ = 3.273) was high in comparison with other species within the genus. Mortality ofB. elongatum(Z = 1.075 year−1) was well fitted to the single exponential model (r2= 0.92). The annual total production ofB. elongatumreached 0.68 g ash-free dry mass (AFDM) m−2and the annual mean biomass was 0.56 g AFDM m−2, which determined a production to biomass ratio of 1.22. The huge productivity of the HCS was not reflected in a high abundance and biomass ofB. elongatum. However, this species displayed a high growth efficiency and P/B ratio that are comparable to those of otherBranchiostomainhabiting highly productive ecosystems.
A BCI-controlled robotic assistant for quadriplegic people in domestic and professional life
Authors: Grigorescu Sorin M. , Lüth Thorsten , Fragkopoulos Christos , Cyriacks Marco , Gräser Axel
Published: July 2011

In this paper, a Brain–Computer Interface (BCI) control approach for the assistive robotic system FRIEND is presented. The objective of the robot is to assist elderly and persons with disabilities in their daily and professional life activities. FRIEND is presented here from an architectural point of view, that is, as an overall robotic device that includes many subareas of research, such as human–robot interaction, perception, object manipulation and path planning, robotic safety, and so on. The integration of the hardware and software components is described relative to the interconnections between the various elements of FRIEND and the approach used for human–machine interaction. Since the robotic system is intended to be used especially by patients suffering from a high degree of disability (e.g., patients which are quadriplegic, have muscle diseases or serious paralysis due to strokes, or any other diseases with similar consequences for their independence), an alternative non-invasive BCI has been investigated. The FRIEND–BCI paradigm is explained within the overall structure of the robot. The capabilities of the robotic system are demonstrated in three support scenarios, one that deals with Activities of daily living (ADL) and two that are taking place in a rehabilitation workshop. The proposed robot was clinically evaluated through different tests that directly measure task execution time and hardware performance, as well as the acceptance of robot by end-users.
Complete spacelike hypersurfaces in a Robertson–Walker spacetime
Authors: ALBUJER ALMA L. , CAMARGO FERNANDA E. C. , DE LIMA HENRIQUE F.
Published: July 2011

In this paper, as a suitable application of the well-known generalized maximum principle of Omori–Yau, we obtain uniqueness results concerning to complete spacelike hypersurfaces with constant mean curvature immersed in a Robertson–Walker (RW) spacetime. As an application of such uniqueness results for the case of vertical graphs in a RW spacetime, we also get non-parametric rigidity results.
Predictors of rapid cognitive decline in Alzheimer's disease: results from the Australian Imaging, Biomarkers and Lifestyle (AIBL) study of ageing
Authors: Sona Alessandro , Zhang Ping , Ames David , Bush Ashley I. , Lautenschlager Nicola T. , Martins Ralph N. , Masters Colin L. , Rowe Christopher C. , Szoeke Cassandra , Taddei Kevin , Ellis Kathryn A. ,   AIBL Research Group
Published: July 2011

Background:The AIBL study, which commenced in November 2006, is a two-center prospective study of a cohort of 1112 volunteers aged 60+. The cohort includes 211 patients meeting NINCDS-ADRDA criteria for Alzheimer's disease (AD) (180 probable and 31 possible). We aimed to identify factors associated with rapid cognitive decline over 18 months in this cohort of AD patients.

Methods:We defined rapid cognitive decline as a drop of 6 points or more on the Mini-Mental State Examination (MMSE) between baseline and 18-month follow-up. Analyses were also conducted with a threshold of 4, 5, 7 and 8 points, as well as with and without subjects who had died or were too severely affected to be interviewed at 18 months and after, both including and excluding subjects whose AD diagnosis was “possible” AD. We sought correlations between rapid cognitive decline and demographic, clinical and biological variables.

Results:Of the 211 AD patients recruited at baseline, we had available data for 156 (73.9%) patients at 18 months. Fifty-one patients were considered rapid cognitive decliners (32.7%). A higher Clinical Dementia Rating scale (CDR) and higher CDR “sum of boxes” score at baseline were the major predictors of rapid cognitive decline in this population. Furthermore, using logistic regression model analysis, patients treated with a cholinesterase inhibitor (CheI) had a higher risk of being rapid cognitive decliners, as did males and those of younger age.

Conclusions:Almost one third of patients satisfying established research criteria for AD experienced rapid cognitive decline. Worse baseline functional and cognitive status and treatment with a CheI were the major factors associated with rapid cognitive decline over 18 months in this population.
Contribution of farmers' experiments and innovations to Cuba's agricultural innovation system
Authors: Leitgeb Friedrich , Funes-Monzote Fernando R. , Kummer Susanne , Vogl Christian R.
Published: July 2011

Innovations are the driving force for agricultural development under present diverse situations of uncertainty. The innovation system perspective acknowledges the contributions made by all stakeholders involved in knowledge development, dissemination and appropriation. According to the specific agricultural production system, farmers adopt innovations, modify them or innovate on their own. This paper examines the role of farmers' experiments and innovations in Cuba's agricultural innovation system (AIS), identifies knowledge exchange encounters and describes some strategies implemented to institutionalize farmers' experiments and innovations. The research methods comprised 34 semi-structured interviews with agricultural experts from the science, administration and advisory system, and 31 free list questionnaires to assess the institutional influence on farmers' experiments and innovations. In addition, three case studies of outstanding farmers' experiments are presented. The results suggest that the government's commitment to social participation in knowledge development provides the basic prerequisite for an effective integration of farmers' experiments and innovation in Cuba. The historically conditioned vertical structure of knowledge development and dissemination is gradually changing toward more horizontal procedures. The dynamic exchange of ideas at all kinds of interactive meetings, such as workshops or farmers' field schools, have favored farmer to farmer learning as well as knowledge sharing with research, academic and extension officials. This multi-stakeholders' approach contributes to institutionalize farmers' knowledge. Farmers' experiments and innovations play a major role in improving farm management and thereby can contribute to build resilience at the farming system level as well as for the national agricultural system.
Replacement of Hazardous Solvents and Reagents in Analytical Chemistry
Authors: Young Jennifer L. , Raynie Douglas E.
Published: July 2011

This chapter presents numerous alternatives to solvents and reagents for analytical chemistry. Solvents alone often account for most of the waste generated by analytical methods, especially through sample preparation and mobile phases. Efforts to reduce the amount of solvent have been the focus of other chapters and literature. The situation is not as dire as it once was. Particularly hazardous solvents, like benzene and chloroform, and reagents that are persistent, bioaccumulative, and toxic (PBT) compounds, have for the most part been replaced by less hazardous alternatives. There is an increasing awareness of green chemistry across the disciplines, including analytical chemistry, and actions are being taken to improve the environmental footprint of analysis.
The adsorption energy and diffusion of a pentacene molecule on a gold surface
Authors: Wheeler William D. , Parkinson B. A. , Dahnovsky Yuri
Published: July 2011

The nature of the chemical bonding of a pentacene molecule to a gold surface is studied. The calculations are carried out using two very different methodologies, the ab inito gaussian molecular orbital method and a numerical atomic orbital method, developed from the well tested SIESTA approach. Using the GAUSSIAN 09 package, we employ both local density B3LYP, and long-range correlated functionals CAM-B3LYP, ωB97, and ωB97X. For comparison, we also calculate the adsorption energy using the ATOMISTIX TOOLKIT with the revised PBE functional. Within computational and experimental errors we find that the best description of the binding energies can be obtained from GAUSSIAN calculations using long-range ωB97 and ωB97X exchange functionals. Thus the nature of chemical bonding of a pentacene to gold is a van der Waals type. To understand the large variation in the geometries computed by different methods, we calculate energy profiles in both X- and Y-directions. The energy barriers appear to be very small and comparable with the value of room temperature. Thus a pentacene molecule moves on a gold surface with almost no friction at room temperatures. An estimation of the work function is often obtained from a simple electrostatic approach. We test this estimation and find that this approach cannot be used because it significantly underestimates the work function. This investigation gives insights into the structure and bonding of pentacene to a gold surface and provides ideas for the improvement of methodologies for computing the properties of van der Waals adsorbates.
A phase-shift laser scanner based on a time-counting method for high linearity performance
Authors: Yoon Heesun , Song Hajun , Park Kyihwan
Published: July 2011

In the phase-shift measurement method, the distance light travels can be obtained via the phase difference between the reference and the measured signals. In this paper, a multiple-step phase demodulation method with time counting is proposed for measuring the phase difference, with resulting robustness against electric noise. When the phase differences are close to 2nπ (n = 0, 1, 2, …), 2π ambiguity problems commonly occur; here, a time-counting method using a 180°-shifted reference signal is proposed in order to resolve this problem.
On effective electric field nano-octupoling in two dimensions
Authors: Mitus A. C. , Pawlik G. , Zyss J.
Published: July 2011

Conditions towards effective electric field poling in two dimensions (2D) of octupolar molecules which can be achieved are being addressed, based on a lattice model which mimics the basic features of poling. The model is studied using the complementary approaches of analytical methods in statistical mechanics and Monte Carlo simulations. The poling field is imparted by a system of adequately shaped cylindrical electrodes. A topologically rich structure of local and global inhomogeneous octupolar order, including octupolar vortices, is present in the system. The poling criteria are shown to vary strongly throughout the cell: in close proximity to the contact points of neighboring electrodes, a high quality local octupolar order appears at temperature T ≃ 0.1 K while octupoling in the center of the cell requires temperatures as low as 10−4 K. The highly demanding octupoling criteria are ascribed to symmetry-driven effects which decrease the quality of the octupolar phase even in the ground state, as well as to thermal fluctuations and numerical factors at above zero temperatures. Based on our results and using plausible conjectures related to the generalization of the model, it is argued that a weak global octupolar order can be reached at liquid Helium temperatures (a few Kelvins), based on current advances in optical techniques and nanotechnologies.
Temperature dependence of 4.1 μm mid-infrared type II “W” interband cascade lasers
Authors: Ikyo B. A. , Marko I. P. , Adams A. R. , Sweeney S. J. , Canedy C. L. , Vurgaftman I. , Kim C. S. , Kim M. , Bewley W. W. , Meyer J. R.
Published: July 2011

The thermal properties of 5-stage “W” Interband-Cascade Lasers emitting at 4.1 μm at room temperature (RT) are investigated by measuring the lasing and spontaneous emission properties as a function of temperature and hydrostatic pressure up to 1 GPa. Experiments show that at RT more than 90% of threshold current of these devices is due to non-radiative loss processes. We also find that the threshold current density dependence on temperature can be fitted with a single exponential function over a wide temperature range with a characteristic temperature, T0, of 45 K. The relatively high temperature sensitivity in these devices is attributable to the large non-radiative current contribution coupled with non-pinning of the carrier density above threshold.
Dynamics of self-propelled nanomotors in chemically active media
Authors: Thakur Snigdha , Kapral Raymond
Published: July 2011

Synthetic chemically powered nanomotors often rely on the environment for their fuel supply. The propulsion properties of such motors can be altered if the environment in which they move is chemically active. The dynamical properties of sphere dimer motors, composed of linked catalytic and noncatalytic monomers, are investigated in active media. Chemical reactions occur at the catalytic monomer and the reactant or product of this reaction is involved in cubic autocatalytic or linear reactions that take place in the bulk phase environment. For these reactions, as the bulk phase reaction rates increase, the motor propulsion velocity decreases. For the cubic autocatalytic reaction, this net effect arises from a competition between a reduction of the nonequilibrium concentration gradient that leads to smaller velocity and the generation of fuel in the environment that tends to increase the motor propulsion. The role played by detailed balance in determining the form of the concentration gradient in the motor vicinity in the active medium is studied. Simulations are carried out using reactive multiparticle collision dynamics and compared with theoretical models to obtain further insight into sphere dimer dynamics in active media.
Three hard spheres in a spherical cavity
Authors: Urrutia Ignacio
Published: July 2011

This work is devoted to furthering the understanding of few- and many-body inhomogeneous systems in the framework of the statistical mechanics of fluids. The three-body system consisting in three hard spheres (HS) confined in a spherical cavity at constant temperature is studied. Its canonical ensemble partition function and thermodynamic properties (such as the free energy, pressures, and fluid-substrate surface tension) are analytically obtained as a function of the cavity radius. This is the first time that a three-body fluid-like system is exactly solved. Symmetry relations between this system and its dual system composed of three HS surrounding a hard spherical object are analyzed. They allow to analytically obtain the canonical partition function of the dual system and its thermodynamic properties. Finally, the behavior of the many-body system of HS in contact with a hard spherical wall in the low density limit, is studied, focusing on the curvature dependence of the fluid-substrate surface tension and finding exact expressions for the Tolman's length and the second order term in curvature.
Improvement in the leakage current characteristic of metal-insulator-metal capacitor by adopting RuO2 film as bottom electrode
Authors: Han Jeong Hwan , Han Sora , Lee Woongkyu , Lee Sang Woon , Kim Seong Keun , Gatineau Julien , Dussarrat Christian , Hwang Cheol Seong
Published: July 2011

The dielectric constant, equivalent oxide thickness (tox), and leakage current properties of Pt/(Al-doped)TiO2/RuO2 capacitors were examined in comparison with Pt/(Al-doped)TiO2/Ru capacitors. The Al-doped TiO2 and undoped TiO2 films grown on RuO2 showed high dielectric constants of 60 and 102, respectively. The minimum tox of these films were 0.46 nm and 0.56 nm, respectively, while still satisfying the dynamic random access memory leakage current density specification (< 1 × 10−7 Acm−2 at capacitor voltage of 0.8 V). These excellent electrical properties of (Al-doped) TiO2 on RuO2 were attributed to the high work function and the reduced interfacial effect on RuO2.
Optical properties of self assembled GaN polarity inversion domain boundary
Authors: Liu M.-C. , Cheng Y.-J. , Chang J.-R. , Hsu S.-C. , Chang C.-Y.
Published: July 2011

We report the fabrication of GaN lateral polarity inversion heterostructure with self assembled crystalline inversion domain boundaries (IDBs). The sample was fabricated by two step molecular-beam epitaxy (MBE) with microlithography patterning in between to define IDBs. Despite the use of circular pattern, hexagonal crystalline IDBs were self assembled from the circular pattern during the second MBE growth. Both cathodoluminescent (CL) and photoluminescent (PL) measurements show a significant enhanced emission at IDBs and in particular at hexagonal corners. The ability to fabricate self assembled crystalline IDBs and its enhanced emission property can be useful in optoelectronic applications.
Synchrotron x-ray photoelectron spectroscopy study on thermally grown SiO2/4H-SiC(0001) interface and its correlation with electrical properties
Authors: Watanabe Heiji , Hosoi Takuji , Kirino Takashi , Kagei Yusuke , Uenishi Yusuke , Chanthaphan Atthawut , Yoshigoe Akitaka , Teraoka Yuden , Shimura Takayoshi
Published: July 2011

The correlation between atomic structure and the electrical properties of thermally grown SiO2/4H-SiC(0001) interfaces was investigated by synchrotron x-ray photoelectron spectroscopy together with electrical measurements of SiC-MOS capacitors. We found that the oxide interface was dominated by Si-O bonds and that there existed no distinct C-rich layer beneath the SiC substrate despite literature. In contrast, intermediate oxide states in Si core-level spectra attributable to atomic scale roughness and imperfection just at the oxide interface increased as thermal oxidation progressed. Electrical characterization of corresponding SiC-MOS capacitors also indicated an accumulation of both negative fixed charges and interface defects, which correlates well with the structural change in the oxide interface and provides insight into the electrical degradation of thermally grown SiC-MOS devices.
Do young eucalypt plantations benefit bats in an intensive agricultural landscape?
Authors: Law Bradley S. , Chidel Mark , Penman Trent
Published: July 2011

Context
Environmental benefits of timber plantations have been a major selling point for land use change from previously cleared farmland, but data concerning the response of biodiversity are scarce.

Aims
We investigated the use of young (4–11 years old) timber plantations by bats in comparison with other vegetation classes in a highly cleared and productive agricultural landscape in north-west New South Wales (NSW), Australia.

Methods
Initially, we recorded activity in paddocks before plantation establishment, and then four to six years after establishment. We compared activity within young eucalypt plantations with surrounding paddocks and remnant woodland. We also radio-tracked four different bat species to investigate how roosting and foraging was apportioned into different habitats.

Key results
The ultrasonic survey of bats found that the young plantations were typically used by 7–8 species and activity averaged 87 passes per night. Activity within plantations was similar to treeless paddocks, and approximately six times less than in small remnants. The very high activity levels and feeding buzzes in small remnants was significantly related to rich, basalt soil (which was used as a proxy for invertebrate biomass) on agricultural plains. Total activity and species richness was correlated positively with the number of remnant trees on the site, but neither plantation area nor shape influenced bat activity. Plantations were not used preferentially by radio-tracked bats at night compared with their availability in the local landscape (13–14% bat use, 17% available). No bat roosts were located within the plantations. Most bat roosts were in tree hollows, which were absent in the plantations. Decorticating bark was abundant in eucalypt plantations, but only Nyctophilus geoffroyi was observed beneath bark and only in remnant trees outside of plantations.

Conclusions
Young eucalypt plantations have limited value for bats, and this is comparable to previous studies on more environmentally focussed plantings.

Implications
The value of plantations for bats would be improved by retaining remnant trees, both in the surrounding landscape and within plantations. We also recommend varying tree densities to increase the diversity of animal species using plantations.
Blood flow restriction reduces time to muscular failure
Authors: Loenneke Jeremy P. , Balapur Abhishek , Thrower Austin D. , Barnes Jeremy , Pujol Thomas J.
Published: July 2011

Exercise to failure results in similar muscle protein synthesis responses, independent of intensity. However, low‐intensity exercise likely requires more repetitions and individuals with injuries may be incapable of sustaining the mechanical stress to reach failure. The aim of this study was to determine if knee wraps provide a stimulus to decrease time to failure. Twenty healthy individuals participated in a randomized crossover study consisting of three trials. The first trial was used to determine one‐repetition maximum (1‐RM) on leg extension. Participants were then assigned to a blood flow restriction or control group. After trial 2, participants crossed over to the opposite trial. Knee wraps were placed around the upper thigh of each leg during blood flow restriction. Leg extensions were completed at 30% 1‐RM until failure. A rating of perceived exertion was taken after exercise and whole blood samples were taken before, after, and 3 min after exercise for the determination of lactate. Repetitions until failure and total work were significantly lower with practical blood flow restriction compared with the control trial. Metabolic stress as measured by whole blood lactate was higher immediately after muscular failure in the control compared with the blood flow restriction trial, but not so 3 min after exercise. There were no differences in ratings of perceived exertion. In conclusion, knee wraps provide a stimulus for blood flow restriction allowing failure to occur sooner with similar metabolic stress after reperfusion. However, similar perceptual responses despite the lower workload with blood flow restriction may limit its application to the highly motivated.
Ab initioStudy on Ionization Energies of 3-Amino-1-propanol
Authors: Wang Ke-dong , Jia Ying-bin , Lai Zhen-jiang , Liu Yu-fang
Published: July 2011

Fourteen conformers of 3-amino-1-propanol as the minima on the potential energy surface are examined at the MP2/6-311++G** level. Their relative energies calculated at B3LYP, MP3 and MP4 levels of theory indicated that two most stable conformers display the intramolecular OH···N hydrogen bonds. The vertical ionization energies of these conformers calculated with ab initio electron propagator theory in the P3/aug-cc-pVTZ approximation are in agreement with experimental data from photoelectron spectroscopy. Natural bond orbital analyses were used to explain the differences of IEs of the highest occupied molecular ortibal of conformers. Combined with statistical mechanics principles, conformational distributions at various temperatures are obtained and the temperature dependence of photoelectron spectra is interpreted.
Adsorption of Cationic Laser Dye onto Polymer/Surfactant Complex Film
Authors: Kumar Paul Pabitra , Arshad Hussain Syed , Bhattacharjee Debajyoti , Pal Mrinal
Published: July 2011

Fabrication of complex molecular films of organic materials is one of the most important issues in modern nanoscience and nanotechnology. Soft materials with flexible properties have been given much attention and can be obtained through bottom up processing from functional molecules, where self-assembly based on supramolecular chemistry and designed assembly have become crucial processes and technologies. In this work, we report the successful incorporation of cationic laser dye rhodamine 6G abbreviated as R6G into the pre-assembled polyelectrolyte/surfactant complex film onto quartz substrate by electrostatic adsorption technique. Poly(allylamine hydrochloride) (PAH) was used as polycation and sodium dodecyl sulphate (SDS) was used as anionic surfactant. UV-Vis absorption spectroscopic characterization reveals the formation of only H-type aggregates of R6G in their aqueous solution and both H- and J-type aggregates in PAH/SDS/R6G complex layer-by-layber films as well as the adsorption kinetics of R6G onto the complex films. The ratio of the absorbance intensity of two aggregated bands in PAH/SDS/R6G complex films is merely independent of the concentration range of the SDS solution used to fabricate PAH/SDS complex self-assembled films. Atomic force microscopy reveals the formation of R6G aggregates in PAH/SDS/R6G complex films.
Molecular Characterization of Two Types of Resistance in Sunflower to Plasmopara halstedii, the Causal Agent of Downy Mildew
Authors: Radwan Osman , Bouzidi Mohamed Fouad , Mouzeyar Said
Published: July 2011

Depending on host–pathotype combination, two types of sunflower–Plasmopara halstedii incompatibility reactions have previously been identified. Type I resistance can restrict the growth of the pathogen in the basal region of the hypocotyls, whereas type II cannot, thus allowing the pathogen to reach the cotyledons. In type II resistance, a large portion of the hypocotyls is invaded by the pathogen and, subsequently, a hypersensitive reaction (HR) is activated over a long portion of the hypocotyls. Thus, the HR in type II resistance coincides with a higher induction of hsr203j sunflower homologue in comparison with type I resistance, where the HR is activated only in the basal part of hypocotyls. Although the pathogen was not detected in cotyledons of type I resistant plants, semiquantitative polymerase chain reaction confirmed the early abundant growth of the pathogen in cotyledons of susceptible plants by 6 days postinfection (dpi). This was in contrast to scarce growth of the pathogen in cotyledons of type II-resistant plants at a later time point (12 dpi). This suggests that pathogen growth differs according to the host–pathogen combination. To get more information about sunflower downy mildew resistance genes, the full-length cDNAs of RGC151 and RGC203, which segregated with the PlARG gene (resistance type I) and Pl14 gene (resistance type II), were cloned and sequenced. Sequence analyses revealed that RGC151 belongs to the Toll/interleukin-1 receptor (TIR) nucleotide-binding site leucine-rich repeat (NBS-LRR) class whereas RGC203 belongs to class coiled-coil (CC)-NBS-LRR. This study suggests that type II resistance may be controlled by CC-NBS-LRR gene transcripts which are enhanced upon infection by P. halstedii, rather than by the TIR-NBS-LRR genes that might control type I resistance.
Ancestry and evolution of seasonal migration in the Parulidae
Authors: Winger Benjamin M. , Lovette Irby J. , Winkler David W.
Published: July 2011

Seasonal migration in birds is known to be highly labile and subject to rapid change in response to selection, such that researchers have hypothesized that phylogenetic relationships should neither predict nor constrain the migratory behaviour of a species. Many theories on the evolution of bird migration assume a framework that extant migratory species have evolved repeatedly and relatively recently from sedentary tropical or subtropical ancestors. We performed ancestral state reconstructions of migratory behaviour using a comprehensive, well-supported phylogeny of the Parulidae (the ‘wood-warblers’), a large family of Neotropical and Nearctic migratory and sedentary songbirds, and examined the rates of gain and loss of migration throughout the Parulidae. Counter to traditional hypotheses, our results suggest that the ancestral wood-warbler was migratory and that losses of migration have been at least as prevalent as gains throughout the history of Parulidae. Therefore, extant sedentary tropical radiations in the Parulidae represent losses of latitudinal migration and colonization of the tropics from temperate regions. We also tested for phylogenetic signal in migratory behaviour, and our results indicate that although migratory behaviour is variable within some wood-warbler species and clades, phylogeny significantly predicts the migratory distance of species in the Parulidae.
The cost of dominance: suppressing subordinate reproduction affects the reproductive success of dominant female banded mongooses
Authors: Bell M. B. V. , Nichols H. J. , Gilchrist J. S. , Cant M. A. , Hodge S. J.
Published: July 2011

Social species show considerable variation in the extent to which dominant females suppress subordinate reproduction. Much of this variation may be influenced by the cost of active suppression to dominants, who may be selected to balance the need to maximize the resources available for their own offspring against the costs of interfering with subordinate reproduction. To date, the cost of reproductive suppression has received little attention, despite its potential to influence the outcome of conflict over the distribution of reproduction in social species. Here, we investigate possible costs of reproductive suppression in banded mongooses, where dominant females evict subordinates from their groups, thereby inducing subordinate abortion. We show that evicting subordinate females is associated with substantial costs to dominant females: pups born to females who evicted subordinates while pregnant were lighter than those born after undisturbed gestations; pups whose dependent period was disrupted by an eviction attained a lower weight at independence; and the proportion of a litter that survived to independence was reduced if there was an eviction during the dependent period. To our knowledge, this is the first empirical study indicating a possible cost to dominants in attempting to suppress subordinate breeding, and we argue that much of the variation in reproductive skew both within and between social species may be influenced by adaptive variation in the effort invested in suppression by dominants.
Open chromatin defined by DNaseI and FAIRE identifies regulatory elements that shape cell-type identity
Authors: Song Lingyun , Zhang Zhancheng , Grasfeder Linda L. , Boyle Alan P. , Giresi Paul G. , Lee Bum-Kyu , Sheffield Nathan C. , Gräf Stefan , Huss Mikael , Keefe Damian , Liu Zheng , London Darin , McDaniell Ryan M. , Shibata Yoichiro , Showers Kimberly A. , Simon Jeremy M. , Vales Teresa , Wang Tianyuan , Winter Deborah , Zhang Zhuzhu , Clarke Neil D. , Birney Ewan , Iyer Vishwanath R. , Crawford Gregory E. , Lieb Jason D. , Furey Terrence S.
Published: July 2011

The human body contains thousands of unique cell types, each with specialized functions. Cell identity is governed in large part by gene transcription programs, which are determined by regulatory elements encoded in DNA. To identify regulatory elements active in seven cell lines representative of diverse human cell types, we used DNase-seq and FAIRE-seq (Formaldehyde Assisted Isolation of Regulatory Elements) to map “open chromatin.” Over 870,000 DNaseI or FAIRE sites, which correspond tightly to nucleosome-depleted regions, were identified across the seven cell lines, covering nearly 9% of the genome. The combination of DNaseI and FAIRE is more effective than either assay alone in identifying likely regulatory elements, as judged by coincidence with transcription factor binding locations determined in the same cells. Open chromatin common to all seven cell types tended to be at or near transcription start sites and to be coincident with CTCF binding sites, while open chromatin sites found in only one cell type were typically located away from transcription start sites and contained DNA motifs recognized by regulators of cell-type identity. We show that open chromatin regions bound by CTCF are potent insulators. We identified clusters of open regulatory elements (COREs) that were physically near each other and whose appearance was coordinated among one or more cell types. Gene expression and RNA Pol II binding data support the hypothesis that COREs control gene activity required for the maintenance of cell-type identity. This publicly available atlas of regulatory elements may prove valuable in identifying noncoding DNA sequence variants that are causally linked to human disease.
The relation between hypothalamic–pituitary–adrenal (HPA) axis activity and age of onset of alcohol use
Authors: Evans Brittany E. , Greaves‐Lord Kirstin , Euser Anja S. , Franken Ingmar H. A. , Huizink Anja C.
Published: July 2011

Aims  Hypothalamic–pituitary–adrenal (HPA) axis activity may prove a viable biomarker for identifying those susceptible to alcohol use disorders. The purpose of this study was to examine the relation of the age at which adolescents begin drinking with diurnal and stress cortisol.

Design  Adolescents' diurnal cortisol levels on a normal day and cortisol levels during a stress procedure were examined in relation to the age of onset of alcohol use.

Setting and participants  All adolescents (aged 14–20 years) were part of a general population study in the Netherlands (n = 2286).

Measurements  Ten assessments of salivary cortisol taken on a normal day (diurnal cortisol), as well as during a social stress procedure (stress cortisol) were used as indicators of HPA axis activity.

Findings  The age at which the first alcoholic drink was consumed varied as a function of cortisol levels at the onset of as well as during the stress procedure. Those who began drinking at an earlier age showed lower cortisol levels at the onset of the stressful tasks (r2 = 0.14, P < 0.001) and during the stressful tasks (r2 = 0.10, P < 0.05), although not after the tasks (cortisol recovery). Effects were strongest for anticipatory pre‐task cortisol levels. Differences in diurnal cortisol levels did not explain variance in the age at which adolescents had begun drinking.

Conclusions  Lessened activity of the hypothalamic–pituitary–adrenal axis at the onset of and during a stress procedure is present in adolescents who begin drinking at an early age.