bluuebunny/crossref_metadata_2025_split huggingface dataset:
The biology of the germ line in echinoderms
Authors: Wessel Gary M. , Brayboy Lynae , Fresques Tara , Gustafson Eric A. , Oulhen Nathalie , Ramos Isabela , Reich Adrian , Swartz S. Zachary , Yajima Mamiko , Zazueta Vanessa 
Published: July 2013

SUMMARYThe formation of the germ line in an embryo marks a fresh round of reproductive potential. The developmental stage and location within the embryo where the primordial germ cells (PGCs) form, however, differs markedly among species. In many animals, the germ line is formed by an inherited mechanism, in which molecules made and selectively partitioned within the oocyte drive the early development of cells that acquire this material to a germ‐line fate. In contrast, the germ line of other animals is fated by an inductive mechanism that involves signaling between cells that directs this specialized fate. In this review, we explore the mechanisms of germ‐line determination in echinoderms, an early‐branching sister group to the chordates. One member of the phylum, sea urchins, appears to use an inherited mechanism of germ‐line formation, whereas their relatives, the sea stars, appear to use an inductive mechanism. We first integrate the experimental results currently available for germ‐line determination in the sea urchin, for which considerable new information is available, and then broaden the investigation to the lesser‐known mechanisms in sea stars and other echinoderms. Even with this limited insight, it appears that sea stars, and perhaps the majority of the echinoderm taxon, rely on inductive mechanisms for germ‐line fate determination. This enables a strongly contrasted picture for germ‐line determination in this phylum, but one for which transitions between different modes of germ‐line determination might now be experimentally addressed. Mol. Reprod. Dev. 81: 679–711, 2014. © 2014 Wiley Periodicals, Inc.
Free‐breathing phase contrast MRI with near 100% respiratory navigator efficiency using k‐space‐dependent respiratory gating
Authors: Akçakaya Mehmet , Gulaka Praveen , Basha Tamer A. , Ngo Long H. , Manning Warren J. , Nezafat Reza 
Published: July 2013

PurposeTo investigate the efficacy of a novel respiratory motion scheme, where only the center of k‐space is gated using respiratory navigators, versus a fully respiratory‐gated acquisition for three‐dimensional flow imaging.MethodsThree‐dimensional flow images were acquired axially using a gradient echo sequence in a volume, covering the ascending and descending aorta, and the pulmonary artery bifurcation in 12 healthy subjects (33.2 ± 15.8 years; five men). For respiratory motion compensation, two gating and tracking strategies were used with a 7‐mm gating window: (1) All of k‐space acquired within the gating window (fully gated) and (2) central k‐space acquired within the gating window, and the remainder of k‐space acquired without any gating (center gated). Each scan was repeated twice. Stroke volume, mean flow, peak velocity, and signal‐to‐noise‐ratio measurements were performed both on the ascending and on the descending aorta for all acquisitions, which were compared using a linear mixed‐effects model and Bland–Altman analysis.ResultsThere were no statistical differences between the fully gated and the center‐gated strategies for the quantification of stroke volume, peak velocity, and mean flow, as well as the signal‐to‐noise‐ratio measurements. Furthermore, the proposed center‐gated strategy had significantly shorter acquisition time compared to the fully gated strategy (13:19 ± 3:02 vs. 19:35 ± 5:02, P < 0.001).ConclusionsThe proposed novel center‐gated strategy for three‐dimensional flow MRI allows for markedly shorter acquisition time without any systematic variation in quantitative flow measurements in this small group of healthy volunteers. Magn Reson Med 71:2172–2179, 2014. © 2013 Wiley Periodicals, Inc.
Relaxation by amplitude modulation: A rapid T1 measurement method
Authors: Zou Xiaowei , Brown Truman R. 
Published: July 2013

PurposeA novel longitudinal relaxation time (T1) measurement method using complex amplitude modulation is presented.TheoryThe method applies a series of inversion pulses to the imaged region in accordance with a binary modulation sequence. The longitudinal magnetization acquired in a given pulse repetition time (TR) interval is the sum of the individual longitudinal magnetization recovered during each previous TR interval, weighted by T1 decay factors and the combined effect of all the radiofrequency pulses they have experienced. The demodulated signal for each voxel is an exponential curve with a decaying rate determined by T1 and the acquisition flip angle θ.MethodsSequences using a 15‐cycle pseudorandom binary code were implemented on Siemens 3T Trio with standard gradient echo readout and multislice gradient echo‐planar imaging. The sequences were tested on T1 phantoms and human and compared against inversion recovery method.ResultsOur studies on phantoms and a human volunteer show that T1 estimated from this method is very accurate and well reproducible. The average scan time is ∼1.6 s per slice (full k‐space gradient echo‐planar imaging with matrix size 128 × 128).ConclusionThe current protocol is almost twice as fast as two fastest existing methods. Optimizing protocols and incorporating common acceleration techniques will make it even faster. Magn Reson Med 71:2155–2165, 2014. © 2013 Wiley Periodicals, Inc.
Early pregnancy failure as a training tool for chorionic villus sampling
Authors: Nicholas Sara , Orzechowski Kelly , Potti Sushma , Baxter Jason , Berghella Vincenzo , Weiner Stuart 
Published: July 2013

AbstractObjectivesThe goal of this study is to evaluate the success of a training program in chorionic villus sampling (CVS) of early pregnancy failure (EPF) for maternal‐fetal medicine (MFM) fellows.MethodsWe conducted a retrospective review of a new training program in CVS for MFM fellows. Women with EPF up to 13 weeks estimated gestational age were offered inclusion in our program and counseled on alternatives. Transcervical CVS was performed for both fellow education and cytogenetic diagnosis. The primary outcome was a successful diagnosis, and the secondary outcome was cell growth by fellow experience.ResultsThirty‐nine patients diagnosed with EPF from December 2011 to March 2013 underwent CVS. Villi obtained via CVS yielded a diagnosis in 62% of cases. CVS samples with successful karyotype had more villi but were otherwise similar. CVS by experience showed a trend towards increased success and villi volume after the first five procedures. Abnormal results were obtained in 72% of cases, 15% of which led to changes in care.ConclusionCVS of EPF is an option for the training of MFM fellows as it was acceptable to most patients, and the majority of CVS specimens yielded a karyotype diagnosis. © 2013 John Wiley & Sons, Ltd.
Barriers and facilitators to effective communication experienced by patients with malignant lymphoma at all stages after diagnosis
Authors: van Bruinessen Inge Renske , van Weel‐Baumgarten Evelyn M. , Gouw Hans , Zijlstra Josée M. , Albada Akke , van Dulmen Sandra 
Published: July 2013

AbstractObjectiveThis study aims to gain insight into patient‐perceived communication barriers and facilitators at different stages after the diagnosis of malignant lymphoma. We have detected patterns to explain when these factors influence communication predominantly.MethodA qualitative approach was applied, derived from the context mapping framework. A total of 28 patients completed a set of assignments about their experiences with provider‐patient communication during medical consultations. Subsequently, these patients and nine companions shared their experiences during a semistructured (group) interview, which was recorded on audiotape. The audiotapes and assignments were analysed with MAXQDA software.ResultsFrom the patients' viewpoint, communicating effectively appears to depend on their own attributes (e.g. emotions), the health care professionals' attributes (e.g. attitude) and external factors (e.g. time pressure). Three patient communication states were identified: (i) overwhelmed, passive; (ii) pro‐active, self‐motivated; and (iii) proficient, empowered. Patients seem to behave differently in the three communication states.ConclusionsThis study lists patient‐perceived communication barriers and facilitators and identifies three different communication states, which indicate when certain barriers and facilitators are encountered.Practical implicationsThese findings may support health care professionals to tailor the provision of support and information and remove communication barriers accordingly. Additionally, they provide input for interventions to support patients in effective communication. Copyright © 2013 John Wiley & Sons, Ltd.
Injection and temperature dependent carrier recombination rate and diffusion length in freestanding CVD diamond
Authors: Ščajev Patrik , Gudelis Vytautas , Tallaire Alexandre , Barjon Julien , Jarašiūnas Kęstutis 
Published: July 2013

AbstractWe applied time‐resolved nonlinear optical techniques for investigation of carrier recombination and diffusion processes in a 420 μm thick CVD diamond, relatively free from structural and point defects. Injection of 1015–1017 cm−3 carrier density by two‐photon excitation and monitoring free carrier absorption decay in 80–800 K range provided lifetime of 720 ns at T ≥ 300 K. At low temperatures, a linear increase of the carrier recombination rate with the injection level was fitted by an effective bimolecular recombination coefficient B = 10−11–10−9 cm3 s−1 and attributed to the impact of excitons and biexcitons, contributing to phonon‐assisted indirect Auger recombination. At high temperatures, increase of recombination rate was governed by Coulomb enhanced direct Auger process with a 520 meV threshold. An ambipolar carrier mobility with its peak value of ∼1500 cm2 V−1 s−1 at room temperature was determined by transient grating technique at ∼2 × 1015 cm−3 excess carrier density. A strong decrease of mobility at higher injections revealed the role of carrier‐carrier scattering, exciton formation and bandgap renormalization. The simultaneous measurements of carrier lifetime and diffusivity provided carrier diffusion length, which varied in a 1–50 μm range, depending on injection and temperature.
Crystallite size dependent carrier recombination rate and thermal diffusivity in undoped and boron doped CVD diamond layers
Authors: Ščajev P. , Nargelas S. , Jarašiūnas K. , Kisialiou I. , Ivakin E. , Deferme W. , D'Haen J. , Haenen K. 
Published: July 2013

AbstractCarrier dynamics under interband carrier injection conditions (213 nm) was studied in undoped and boron‐doped microcrystalline diamond layers with different grain size. The grain size, determined by scanning electron microscopy and electron backscattered diffraction, varied from 130 μm on the growth side to ∼1–2 μm on the nucleation side of a 1.0 mm‐thick undoped layer. Carrier lifetimes measured by differential transmittivity (DT) technique varied from 1 to 4 ns on the growth side to ∼220 ps on the nucleation side. Also the carrier diffusivity was found higher on the growth side. The B‐doped layer with 40 μm grain size at the growth side exhibited 380 ps carrier lifetime, which decreased to 130 ps on the nucleation side. Even shorter lifetimes (∼100–200 ps and ∼10 ps, correspondingly) were revealed in this layer by differential reflectivity decay due to impact of subsurface defects. Therefore we conclude that the recombination rate in presence of large grains is dominated by bulk non‐radiative traps, as diffusion time of carriers to reach grain boundaries is much longer (few μs). An impact of grain boundaries to recombination is expected in case of smaller grains. Thermal grating decay provided values of thermal diffusivity Dth in the range of 12–6 cm2 s−1, respectively, on the growth and nucleation side of the layers, and its decrease with reduction of grain size was attributed to phonon scattering on grain boundaries.
REVISION OF THE BIOLOGICAL MONITORING WORKING PARTY (BMWP) SCORE SYSTEM: DERIVATION OF PRESENT‐ONLY AND ABUNDANCE‐RELATED SCORES FROM FIELD DATA
Authors: Paisley M. F. , Trigg D. J. , Walley W. J. 
Published: July 2013

ABSTRACTThe Biological Monitoring Working Party (BMWP) score system was introduced in 1980 to provide an index of river water quality for England and Wales based on aquatic macroinvertebrates. The score allocated to each taxon was set by a group of expert river biologists on the basis of their collective experience of the taxon's sensitivity to organic pollution. This paper describes an objective reappraisal of these subjectively derived scores by the statistical analysis of a large and comprehensive database of field data. Two different methods of using biological and environmental data were evaluated as a basis for revising BMWP scores, both of which accounted for variations in site type. One method, Modified New Walley–Hawkes (MNWH), used a modified average score per taxon (MASPT) as its ranking metric and required analyses performed on separated data sets divided into three site types. The other method used the environmental quality index based on MASPT (EQIMASPT) to provide its ranking metric. Both of these methods involved the use of modified BMWP values for Oligochaeta and Chironomidae for reasons that are explained. Following evaluation, the MNWH method was chosen to derive present‐only and abundance‐related scores for the BMWP taxa, 19 additional taxa mostly from the order Diptera, and 16 extra taxa resulting from the splitting of eight BMWP composite taxa. The MNWH scores were generally in keeping with those derived in an earlier study, except for a few rare taxa that were represented by few samples in that study. The UK Regulatory Authorities intend adopting a new index based on the MNWH scores, and this is given in two appendices. Copyright © 2013 John Wiley & Sons, Ltd.
Morphological feature extraction for statistical learning with applications to solar image data
Authors: Stenning David C. , Lee Thomas C. M. , van Dyk David A. , Kashyap Vinay , Sandell Julia , Young C. Alex 
Published: July 2013

AbstractMany areas of science are generating large volumes of digital image data. In order to take full advantage of the high‐resolution and high‐cadence images modern technology is producing, methods to automatically process and analyze large batches of such images are needed. This involves reducing complex images to simple representations such as binary sketches or numerical summaries that capture embedded scientific information. Using techniques derived from mathematical morphology, we demonstrate how to reduce solar images into simple ‘sketch’ representations and numerical summaries that can be used for statistical learning. We demonstrate our general techniques on two specific examples: classifying sunspot groups and recognizing coronal loop structures. Our methodology reproduces manual classifications at an overall rate of 90% on a set of 119 magnetogram and white light images of sunspot groups. We also show that our methodology is competitive with other automated algorithms at producing coronal loop tracings and demonstrate robustness through noise simulations. © 2013 Wiley Periodicals, Inc. Statistical Analysis and Data Mining, 2013
Linguistic Challenges in Mendelian Genetics: Teachers’ Talk in Action
Authors: THÖRNE KARIN , GERICKE NIKLAS M. , HAGBERG MARIANA 
Published: July 2013

ABSTRACTThis study investigates Swedish teachers’ use of language when teaching Mendelian genetics in compulsory school. The primary objective of the study is to explore how teachers use the related concepts gene, allele, and anlag (a Swedish variant of the German word anlage) and how these are related to trait, central relations that have been identified as problematic in genetics education. Four teachers were recorded while teaching genetics. The empirical data consist of 45 recorded lessons. The teachers’ verbal communications were analyzed using a linguistic framework called thematic pattern analysis. The results showed a predominant use of the word anlag over gene, whereas there was a total lack of use of the word allele. The word anlag was used to mean both gene and trait. Anlag was also used as a synonym for allele. The teachers’ language conveyed four categories of meanings regarding the gene‐to‐trait relationship: genes control traits, are identified by traits, have traits, or are traits. This study thus highlights several linguistic challenges in the teaching of Mendelian genetics that might affect students’ learning. Moreover, the study exemplifies how a linguistics methodology can be used to investigate science teaching. © 2013 Wiley Periodicals, Inc. Sci Ed 97:695–722, 2013
Mental Well‐Being Mediates the Relationship between Perceived Stress and Perceived Health
Authors: Teh Hui Chian , Archer Josephine A. , Chang Weining , Chen SH Annabel 
Published: July 2013

AbstractThe association between stress and health has been well researched in the past; however, comparatively few mediators have been tested to understand the underlying mechanism. With increasing awareness on mental well‐being, this study evaluated the relationship between perceived stress and perceived health and examined mental well‐being as a mediator. Two‐hundred undergraduates aged 21 to 26 years completed the English Perceived Stress Scale, Health Status Questionnaire and Asian Mental Well‐Being Scale that assess perceived stress, perceived health and mental well‐being, respectively. Factor analysis and structural equation modelling on the Perceived Stress Scale replicated the reported two‐factor structure after excluding an insignificant item. Linear multiple regression analyses indicated that perceived stress was negatively associated with perceived health. Results showed that mental well‐being partially mediated the relationship between perceived stress and perceived health, although it is acknowledged that this association could be bidirectional. Findings from the present study suggest that future research could focus on reducing stress and improving mental well‐being to alleviate the effect of stress on health. Copyright © 2013 John Wiley & Sons, Ltd.
Finite element modeling and parametric analysis of timber–steel hybrid structures
Authors: Li Zheng , He Minjuan , Lam Frank , Li Minghao , Ma Renle , Ma Zhong 
Published: July 2013

SUMMARYThis paper presents finite element modeling and a parametric analysis of prototype timber–steel hybrid structures, which are composed of steel moment‐resisting frames and infill wood‐frame shear walls. A user‐defined element was developed to model the behavior of the infill wood shear walls based on the concept of pseudo‐nail model. The element was implemented as a subroutine in a finite element software package abaqus. The model was verified by reversed cyclic test results and further used in a parametric analysis to investigate the lateral performance of timber–steel hybrid shear walls with various structural configurations. The results showed that the infill wall was quite effective within small drift ratios, and the elastic lateral stiffness of the hybrid shear wall increased when a stronger infill wall was used. In order to ensure the structural efficiency of the hybrid shear wall system, it is beneficial to use relatively strong timber–steel bolted connections to make sure the shear force can be transferred effectively between the steel frame and the infill wall. Copyright © 2013 John Wiley & Sons, Ltd.
Young Learners and Lexical Awareness: Children's Engagement With Wordlists and Concordances
Authors: MacGregor Alex 
Published: July 2013

Sinclair (1991) found that lexical analysis can be overcomplicated, yet Johns (1994) called for investigation into whether corpus analysis can motivate beginners and near‐beginners. The findings of this research suggest that young EFL learners can enjoy using corpus analysis tools (wordlists and concordances) to identify, classify, and generalize about English. The teacher‐researcher developed a series of classroom activities in which students created wordlists and discovered and recorded collocations. Quantitative data gathered over 1 year from yes/no and ranking questions indicate that students found the activities enjoyable, and 230 write‐in comment sheets provided qualitative data that support the motivational impact of the activities. Findings suggest that as corpora, particularly of children's language, are created and expanded upon, it is vital that classroom activities developed to target meaningful young learner language present this relevant language in an enjoyable, engaging manner.
The Impact of 3 exotic, invasive grasses in the Southeastern United States on wildlife
Authors: Barnes Thomas G. , DeMaso Stephen J. , Bahm Matt A. 
Published: July 2013

ABSTRACTLittle is known about the impacts and effects of exotic, invasive grasses on wildlife in the Southeast United States. We selected 3 species of exotic grasses common to the Southeast and review the literature on their regional distribution, ecosystem impacts, wildlife impacts, and management. These grasses have the potential to harm indigenous wildlife species, such as northern bobwhite (Colinus virginianus), that need grasslands with a shrub component for nesting, brood‐rearing, and loafing. These exotic, invasive grasses are sod‐forming in nature, typically forming dense monotypic stands that provide little bare ground and have low plant species and insect diversity. Furthermore, it appears that wildlife do not prefer to consume these plant species. Control is often difficult and usually requires the use of herbicides in combination with mechanical treatment, such as disking, to provide adequate habitat. Attempts should be encouraged to convert these idle grasslands to a mixture of native grasses and forbs to make stands more suitable for wildlife species. We provide suggestions for future research and management needs regarding exotic, invasive grasses and wildlife in the Southeast United States. © 2013 The Wildlife Society.
Ternary Phase Diagram of β‐Sitosterol–γ‐Oryzanol–Canola Oil
Authors: AlHasawi F. M. , Rogers M. A. 
Published: July 2013

Abstractβ‐Sitosterol and γ‐oryzanol have been shown to form unique structures in canola oil that have the potential to act as saturated and trans fat replacers [1–7]. The ternary phase, reported herein, illustrates numerous interesting physical systems. At high canola oil ratios with low β‐sitosterol and γ‐oryzanol concentrations, the system has a crystal structure capable of mimicking fat crystal networks. Four mesophases are identified based on Bragg's ratios using small angle X‐ray scattering. Two mesophases are lamellar crystals, one is the cubic P phase, and the fourth is an amorphous material due to the low solids content. Wide‐angle X‐ray further subcategorized the phases based on polymorphic divisions of the hydrocarbon side chain packing. In all, six distinct phases are reported, ranging from lamellar crystals, to liquid crystals to what appears to be a lipid glass.