bluuebunny/crossref_metadata_2025_split huggingface dataset:
1200 V SiC vertical‐channel‐JFETs and cascode switches
Authors: Veliadis Victor 
Published: May 2009

AbstractWide band gap semiconductors like silicon carbide (SiC) are currently being developed for high power/temperature applications. Silicon carbide is ideally suited for power switching due to its high saturated drift velocity, its high critical field strength, its excellent thermal conductivity, and its mechanical strength. For power devices, the tenfold increase in critical field strength of SiC relative to Si allows high voltage blocking layers to be fabricated significantly thinner than those of comparable Si devices. This reduces device on‐state resistance and the associated conduction and switching losses, while maintaining the same high voltage blocking capability. The specific on‐state resistance of 4H‐SiC is approximately 400 times lower than that of Si at a given breakdown voltage. This allows for high current operation at relatively low forward voltage drop. In addition, the wide band gap of SiC allows operation at high temperatures where conventional Si devices fail. In this article, we will review Northrop Grumman's single‐implant no‐epitaxial‐regrowth vertical‐channel JFET. The feasibility of efficient 1200 V normally‐off VJFET operation will be investigated. The all‐SiC VJFET based cascode switch will be introduced and aspects of its operation evaluated. High temperature DC characteristics of VJFETs and 1200 V normally‐off cascode switches will be discussed. Finally, the development of large‐area high‐current 1200 V VJFETs and their edge termination performance will be presented. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Identification and carrier dynamics of the dominant lifetime limiting defect in n– 4H‐SiC epitaxial layers
Authors: Klein P. B. 
Published: May 2009

AbstractThe identity and characteristics of the lifetime limiting defects in n‐type 4H‐SiC epitaxial layers are of particular current interest, due to the suitability of this material for high‐power, solid‐state switching devices. Much work has been done in the past decade to identify the spectral signature and the local atomic structure of the defect that controls the lifetime in this material. Until recently, it was concluded that two dominant electron traps, Z1/2 and EH6/7, both associated with a carbon vacancy, were controlling the lifetime. DLTS and optical studies show, however, that EH6/7 is not an important minority carrier trap, due to its small capture cross section for holes. Thus, Z1/2 acts alone as the lifetime limiting defect. The details of recombination at this trap have been studied through the injection level and temperature dependence of the carrier lifetime and through carrier dynamics simulations that take into account the complex nature of the defect. The simulations shed light on the processes that dominate the recombination at Z1/2 over a large range of injection level and temperature. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Mechanism of protective action of mangiferin on suppression of inflammatory response and lysosomal instability in rat model of myocardial infarction
Authors: Prabhu S. , Narayan Shoba , Devi C. S. Shyamala 
Published: May 2009

AbstractLysosomal instability has been suggested as a major factor in the development of cellular injury during myocardial necrosis through the formation of inflammatory mediators. The present study was designed to investigate the effect of mangiferin on lysosomal hydrolases and TNF‐α production during isoproterenol (ISPH) induced myocardial necrosis in rats. The rats given ISPH (200 mg/kg body weight twice, subcutaneous) for 2 days showed a significant increase in plasma TNF‐α production, serum and heart lysosomal hydrolases activity. ISPH administration to rats resulted in decreased stability of the membranes, which was reflected by the lowered activity of cathepsin‐D and β‐glucuronidase in mitochondrial, nuclear, lysosomal and microsomal fractions. Pretreatment with mangiferin (100 mg/kg body weight, intraperitoneally) for 28 days, significantly prevented the alterations and restored the enzyme activities to near‐normal status. These findings demonstrate that mangiferin could preserve lysosomal integrity through decrease in the inflammatory process and hence establish the cardioprotective effect of mangiferin. Copyright © 2009 John Wiley & Sons, Ltd.
Isolation and identification of hemostatic ingredients from lamiophlomis rotata (Benth.) kudo
Authors: Li Maoxing , Zhang Ruxue , Jia Zhengping , Sheng Jie , Qiu Jianguo , Wang Juan 
Published: May 2009

AbstractLamiophlomis rotata (Benth.) Kudo (LR) is a traditional drug used by Chinese minorities such as Tibetans, Mongolians and Na Xi with the beneficial effects of hemostasis and alleviating pain. Flavonoids ingredients (P1), iridoid glycosides ingredients (P2) and maximus polarity components ingredients (P3) were isolated from the aqueous extract of LR (AELR) with polyamide and macroporous adsorptive resins chromatographic columns. The hemostatic activity of these ingredients was estimated by the changes in bleeding time (BT), clotting time (CT) and blood coagulation parameters in mice or rats. RP‐HPLC was used to analyze the chemical composition of P2. As a result, AELR and P2 significantly shortened BT, CT and thrombin time (TT), and increased fibrinogen (FIB), but P1 and P3 showed no hemostatic effect during the experiment. Moreover, P2 showed satisfactory hemostatic effect with dose‐effect relationship and low toxicity in mice. 8‐Dehydroxy shanzhiside, phloyoside II, shanzhiside methylester, loganin, and 8‐O‐acetylshanzhiside methylester were detected as the main iridoid glycosides in P2 by RP‐HPLC. Our results suggest that iridoid glycosides may be the hemostatic activity ingredients of L. rotata and are a potential hemostatic medicine. Copyright © 2009 John Wiley & Sons, Ltd.
Determination of the deuterium/hydrogen ratio of endogenous urinary steroids for doping control purposes
Authors: Piper Thomas , Thevis Mario , Flenker Ulrich , Schänzer Wilhelm 
Published: May 2009

AbstractThe development and application of a combined gas chromatography/thermal conversion/isotope ratio mass spectrometry (GC/TC/IRMS) method for D/H ratio determination of endogenous urinary steroids are presented. The key element in sample preparation was the consecutive cleanup with high‐performance liquid chromatography of initially native and subsequently acetylated steroids. This strategy enabled sufficient cleanup off all target analytes for determination of their respective D/H values. Ten steroids (11β‐hydroxyandrosterone, 5α‐androst‐16‐en‐3α‐ol, pregnanediol, androsterone, etiocholanolone, testosterone, epitestosterone, 5α‐androstan‐3α,17β‐diol, 5β‐androstan‐3α,17β‐diol and dehydroepiandrosterone) were measured from a single urine specimen. Depending on the biological background, the determination limit for all steroids ranged from 10 to 15 ng/mL for a 20 mL specimen. The method was validated by application of linear mixing models on each steroid and covered repeatability and reproducibility. The specificity of the procedure was ensured by gas chromatography/mass spectrometry (GC/MS) analysis of the sample using equivalent chromatographic conditions to those employed in the GC/TC/IRMS measurement. Within the sample preparation, no isotopic fractionation was observed, and no amount‐dependent shift of the D/H ratios during the measurement was noticed. Possible memory effects occurring during IRMS measurements were corrected by applying a simple rule of proportion. In order to determine the naturally occurring D/H ratios of all implemented steroids, a population of 18 male subjects was analyzed. Relevant mean Δ values among selected steroids were calculated which allowed us to study the metabolic pathways and production sites of all the implemented steroids with additional consideration of the corresponding 13C/12C ratios. Copyright © 2009 John Wiley & Sons, Ltd.
Estimation of average treatment effect with incompletely observed longitudinal data: Application to a smoking cessation study
Authors: Chen Hua Yun , Gao Shasha 
Published: May 2009

AbstractWe study the problem of estimation and inference on the average treatment effect in a smoking cessation trial where an outcome and some auxiliary information were measured longitudinally, and both were subject to missing values. Dynamic generalized linear mixed effects models linking the outcome, the auxiliary information, and the covariates are proposed. The maximum likelihood approach is applied to the estimation and inference on the model parameters. The average treatment effect is estimated by the G‐computation approach, and the sensitivity of the treatment effect estimate to the nonignorable missing data mechanisms is investigated through the local sensitivity analysis approach. The proposed approach can handle missing data that form arbitrary missing patterns over time. We applied the proposed method to the analysis of the smoking cessation trial. Copyright © 2009 John Wiley & Sons, Ltd.
The impact of agile principles on market‐driven software product development
Authors: Dzamashvili Fogelström Nina , Gorschek Tony , Svahnberg Mikael , Olsson Peo 
Published: May 2009

AbstractAgile development methods such as extreme programming (XP), SCRUM, Lean Software Development (Lean SD) and others have gained much popularity during the last years. Agile methodologies promise faster time‐to‐market, satisfied customers and high quality software. While these prospects are appealing, the suitability of agile practices to different domains and business contexts still remains unclear. In this article we investigate the applicability of agile principles in the context of market‐driven software product development (MDPD), focusing on pre‐project activities. This article presents results of a comparison between typical properties of agile methods to the needs of MDPD, as well as findings of a case study conducted at Ericsson, an early adopter of agile product development. The results show misalignment between the agile principles and needs of pre‐project activities in market‐driven development. This misalignment threatens to subtract from the positive aspects of agile development, but maybe more importantly, threaten the overall product development by disabling effective product management. Copyright © 2009 John Wiley & Sons, Ltd.
Does One Size Fit All? The Suitability of Answer Formats for Different Constructs Measured
Authors: Dolnicar Sara , Grün Bettina 
Published: May 2009

Survey research is used to investigate a variety of different constructs, such as beliefs, behavioural intentions, perceptions, preferences and so on. Despite the wide range of constructs studied by social scientists, the ordinal answer format tends to be used across the majority of survey research studies. We challenge this standard approach in survey research by hypothesizing that the ordinal answer format is not optimal under all circumstances. Instead, we propose that the suitability of answer formats depends on the construct measured. We conduct a repeat measurement study using binary, ordinal and metric answer formats measuring two different constructs: beliefs and behavioural intentions. A clear interaction effect between answer formats and constructs is revealed. This supports the notion that no single answer format is optimal for all research problems, but that some constructs are naturally more suitable for certain answer formats than others. These findings call for increased use of pre-studies to determine the optimal answer format before fieldwork is conducted rather than relying on standard answer formats.
The Development of EERA: Software for Assessing Rheumatic Joint Erosions
Authors: Emond Patrick D. , Choi Abram , O'Neill John , Xie Jason , Adachi Rick , Gordon Chris L. 
Published: May 2009

Objective The principal aim of this study was to create a segmentation program, to be used by nonmusculoskeletal or junior fellows, that defines the bones in the metacarpophalangeal joint in a dynamic 3-dimensional image that will lead to higher inter-reader agreement of bone erosion scores. Methods The second to fifth metacarpal head and phalangeal bases of 15 participants were rated according to the Rheumatoid Arthritis Magnetic Resonance Imaging Scoring system by one trained and one untrained reader. Two comparisons were made. The first comparison was between the 2 readers using only the traditional 2-dimensional magnetic resonance image set. The second comparison was between the 2 readers, with the untrained reader using a custom segmentation program with traditional 2-dimensional magnetic resonance image set. Results The software marginally increased inter-reader reliability with the exception of the second metacarpal head, for which reliability was increased substantially. Future work will concentrate on improving image acquisition, better delineate erosions from surrounding bone oedema, and address methods to directly determine erosion volumes. Conclusions Software designed to display dynamic 3-dimensional images enables a relatively untrained user to score the metacarpophalangeal joints in the hand for erosions equivalent to that produced by an expert using the manual methods.
Colour Doppler Ultrasound Assessment of the Normal Neonatal Hip
Authors: Ortiz-Neira Clara L. , Laffan Eoghan , Daneman Alan , Fong Katherine , Roposch Andreas , Ohlsson Arne , Jarrin Jose , Wang Chenghua , Wedge John , Doria Andrea S. 
Published: May 2009

Objective To determine the morphology and hemodynamic characteristics of the arterial vessels of the proximal femur according to specific anatomic regions in asymptomatic neonates in 2 pediatric-based health care institutions. Methods Forty-three neonates (29 female, 14 male; age range, 2 d–3 mo; median age, 3 d) were enrolled in the study. Thirty-two (37%) of 86 hips were classified as Graf type IIA joints (mean alpha angle, 56.0° ± 2.7°), and 54 (63%) were classified as type I joints (mean alpha angle, 65.0° ± 4.6°). Results Colour and spectral Doppler imaging identified vessels running along the acetabular labrum, epiphyseal vessels, and femoral neck. We showed 4 different patterns of vascularity of the hips: radial, parallel, mixed radial–parallel, and indeterminate, however, they were not related to the hip maturity ( P = .3, coronal plane; P = .62, transverse plane) or to the amount of colour pixels identified in each region ( P = .35). The mean number of pixels in the ligamentum teres region was significantly higher than that in other regions of interest ( P = .03). Except for the acetabular labrum arteries, Doppler spectrum waveforms of proximal femur arteries presented with low resistivity. There was a tendency towards females' acetabular arteries presenting with lower peak systolic velocities than males' acetabular arteries ( P = .06). Conclusions Colour Doppler spectrum waveforms and intensity of vascularity in normal neonatal hips differ according to the anatomic region under evaluation. This observation deserves further investigation on its role on the physiopathogenesis of neonatal hip disorders.
Review on early technology assessments of nanotechnologies in oncology
Authors: Retèl Valesca P. , Hummel Marjan J.M. , van Harten Wim H. 
Published: May 2009

Nanotechnology is expected to play an increasingly important role in the diagnostics, prognostics, and management of targeted cancer treatments. While papers have described promising results for nanotechnology in experimental settings, the translation of fundamental research into clinical applications has yet to be widely adopted. In future, policy makers will need to anticipate new developments for clinical implementation and introduce technology assessments. Here we present an overview of the literature on the technology assessments that have already been undertaken on early stage nanotechnology in cancer care, with particular emphasis placed on clinical efficacy, efficiency, logistics, patient‐related features and technology dynamics.Owing to the current stage of development of most nanotechnologies, we found only a limited number of publications describing the application of either Health Technology Assessment (HTA) or Constructive Technology Assessment (CTA). In spite of the promising conclusions of most papers concerning the benefits of clinical implementation, actual clinically relevant applications were rarely encountered, and so far only a few publications report application of systematic forms of technology assessment. Most articles consider aspects of environmental safety, regulation and ethics, often mentioning the need to investigate such issues more thoroughly. Evaluation of financial and organizational aspects is often missing. In order to obtain a realistic perspective on the translation and implementation process there is a need for a broad and systematic evaluation of nanotechnologies at early stages of development. Assessment methods taking technology dynamics into account, such as Constructive Technology Assessment (CTA) should be considered for evaluation purposes.
RESPONSE OF MAIZE TO PHOSPHORUS FROM FERTILIZER AND CHICKEN MANURE IN A SEMI-ARID ENVIRONMENT OF SOUTH AFRICA
Authors: MATERECHERA S. A. , MORUTSE H. M. 
Published: May 2009

SUMMARYChicken manure is a potential source of plant available phosphorous (P) and this field study explored its use for dry land maize production in a soil with very low inherent P levels. The treatments consisted of applying 0, 20, 40 and 80 kg P ha−1each from chicken manure (2.3% P), inorganic fertilizer (single super phosphate, 10.5% P) and a combination of manure and fertilizer. The treatments were replicated four times in a randomized complete block design over two crop seasons. The results revealed that maize growth and yield responded to the P from both manure and fertilizer compared to the control. There were significantly (p< 0.05) taller plants and yield (grain and biomass) in maize supplied with P than control. At each level of P application however, the response was higher for fertilizer than manure. The combination of manure and inorganic fertilizer produced results that were in the middle. There were strong indications that application of chicken manure was associated with increased lodging possibly due to the additional N in the manure, attack by stalk borer (Buseola fusca) and reduced seedling emergence. The application of chicken manure on the other hand led to increased pH and greater residual P content of the soil than fertilizer. It is concluded that chicken manure presents a viable option for supplying P to sustain maize crops in the smallholder farming sector of South Africa and its management warrants further investigation in view of the potential adverse impacts on soil and water resources that can accrue when large amounts are used for a long period.
THE WATER RELATIONS AND IRRIGATION REQUIREMENTS OF BANANA (MUSA SPP.)
Authors: CARR M. K. V. 
Published: May 2009

SUMMARYThe results of research on the water relations and irrigation need of banana are collated and summarised in an attempt to link fundamental studies on crop physiology to irrigation practices. Background information on the ecology of the banana and crop development processes, with emphasis on root growth and water uptake, is presented, followed by reviews of the influence of water stress on gas exchange (stomatal conductance, photosynthesis and transpiration), crop water use, and yield. Emphasis is placed on research that has international relevance and, where appropriate, three geographical areas (the tropics, subtropics and Mediterranean climates) are considered. Although roots can extend to depths of 1.0–1.5 m, the ‘effective’ depth of rooting is usually taken to be 0–0.40 m, sometimes extending to 0.60 m. Stomatal conductance is a sensitive measure of soil water availability and plant water status, whilst transpiration rates can be limited by dry air (saturation deficits >2.0 kPa). In the subtropics, there are seasonal differences in the crop coefficient (Kc) with values ranging from 0.6 in the winter months to about 1.0 Epan in the summer. It is difficult to draw generic conclusions with wide applicability from the irrigation experiments as they were reported. All the components of marketable yield can be enhanced by irrigation whilst applying insufficient water delays crop development. Annual yield responses to irrigation are variable, but water use efficiencies of 40 kg ha−1mm−1(fresh fruit/water applied) have been achieved in the tropics and subtropics (and elsewhere up to 80 kg ha−1mm−1with ‘partial’ replacement of the soil water deficit). To ensure large yields of (marketable) fruit, soil water deficits must be kept low (Ψm > −20 kPa at 0.2 m depth). In the subtropics, this means irrigation intervals should not exceed 2–3 d during the summer. The cooling effect of irrigation with micro-sprinklers on the soil and pseudostem temperatures, compared with drippers, can delay crop development and reduce annual yields by 30%. There is some (limited) evidence that the presence of the B genome contributes to drought tolerance. Yield response factors to irrigation for different growth stages have yet to be confirmed. Opportunities to improve the water productivity of the many, diverse banana cultivars need to be explored further.
The uncertain reasoner: Bayes, logic, and rationality
Authors: Oaksford Mike , Chater Nick 
Published: May 2009

AbstractHuman cognition requires coping with a complex and uncertain world. This suggests that dealing with uncertainty may be the central challenge for human reasoning. InBayesian Rationalitywe argue that probability theory, the calculus of uncertainty, is the right framework in which to understand everyday reasoning. We also argue that probability theory explains behavior, even on experimental tasks that have been designed to probe people's logical reasoning abilities. Most commentators agree on the centrality of uncertainty; some suggest that there is a residual role for logic in understanding reasoning; and others put forward alternative formalisms for uncertain reasoning, or raise specific technical, methodological, or empirical challenges. In responding to these points, we aim to clarify the scope and limits of probability and logic in cognitive science; explore the meaning of the “rational” explanation of cognition; and re-evaluate the empirical case for Bayesian rationality.
The singularity spectrum of the inverse of cookie-cutters
Authors: BARRAL JULIEN , SEURET STÉPHANE 
Published: May 2009

AbstractGibbs measures μ on cookie-cutter sets are the archetype of multifractal measures on Cantor sets. We compute the singularity spectrum of the inverse measure of μ. Such a measure is discrete (it is constituted only by Dirac masses), it satisfies a multifractal formalism and its Lq-spectrum possesses one point of non-differentiability. The results rely on heterogeneous ubiquity theorems.
Invariant measures on the space of horofunctions of a word hyperbolic group
Authors: BOWEN LEWIS 
Published: May 2009

AbstractWe introduce a natural equivalence relation on the space ℋ0 of horofunctions of a word hyperbolic group that take the value 0 at the identity. We show that there are only finitely many ergodic measures that are invariant under this relation. This can be viewed as a discrete analog of the Bowen–Marcus theorem. Furthermore, if η is such a measure and G acts on a probability space (X,μ) by measure-preserving transformations then η×μ is virtually ergodic with respect to a natural equivalence relation on ℋ0×X. This is comparable to a special case of the Howe–Moore theorem. These results are applied to prove a new ergodic theorem for spherical averages in the case of a word hyperbolic group acting on a finite space.