bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modeling measurements of ionospheric density structures using the polarization of high‐frequency waves detected by the Radio Receiver Instrument on the enhanced Polar Outflow Probe
Authors: Gillies R. G. , Hussey G. C. , Sofko G. J. , James H. G. 
Published: March 2012

The Cascade SmallSat and Ionospheric Polar Explorer (CASSIOPE) satellite is to be launched in late 2012. On board this satellite will be a suite of eight scientific instruments composing the enhanced Polar Outflow Probe (ePOP). The Radio Receiver Instrument (RRI) on ePOP will be used to receive high‐frequency (HF) (10–18 MHz) transmissions from ground transmitters such as the Super Dual Auroral Radar Network (SuperDARN) array. Modeling of the characteristics of the HF signal received at ePOP for various ionospheric conditions has been undertaken in preparation for this RRI‐SuperDARN experiment. The effect of ionospheric electron density enhancements and depletions on signal parameters such as polarization and mode delay difference has been modeled. It has been found that at HF the polarization state of the received signal is highly sensitive to regions of locally enhanced or depleted electron density in the ionosphere. In particular, analysis of the orientation angle of the received signal, which changes because of Faraday rotation as the spacecraft passes over a ground transmitter, will allow detection of small‐scale electron density structures (on the order of tens of kilometers) with electron densities as little as 10% different from background values. Because of the sensitivity of the polarization of HF transionospheric waves, the signatures of these small‐scale and relatively weak ionospheric density structures will be apparent. Larger and denser structures will also be detectable from both the polarization state and other signal parameters, such as signal delay. The modeling demonstrates that detailed analysis of the signal parameters received at the ePOP satellite will allow determination of the location, size, and density of structures in the ionosphere.
Epigenetics – relevance to drug safety science
Authors: Priestley Catherine C. , Anderton Mark , Doherty Ann T. , Duffy Paul , Mellor Howard R. , Powell Helen , Roberts Ruth 
Published: March 2012

AbstractEpigenetics describes the study of heritable changes in gene expression that occur in the absence of a change to the DNA sequence. Specific patterns of epigenetic signatures can be stably transmitted through mitosis and cell division and form the molecular basis for developmental stage- and cell type-specific gene expression. Associations have been observed that endogenous and exogenous stimuli can change the epigenetic control of both somatic and stem cell differentiation and thus influence phenotypic behaviours and/or disease progression. In relation to drug safety, DNA methylation changes have been identified in many stages of tumour development following exposure to non-genotoxic carcinogens. However, it is not clear whether DNA methylation changes cause cancer, or arise as a consequence of the transformed state. Toxic agents could act at different levels, by directly modifying the epigenome or indirectly by altering signalling pathways. These alterations in chromatin structure may or may not be heritable but are probably reversible. That said, there is currently insufficient data to support inclusion of epigenetic profiling into pre-clinical evaluation studies. Several international collaborations aim to generate data to determine whether epigenetic modifications are causal links in disease and/or tumour progression. It will only be when an understanding of chemical mode-of-action is required that evaluation of epigenetic changes might be considered. The current toxicological testing battery is expected to identify any potential adverse effects regardless of the mechanism, epigenetic or otherwise. It is recommended that toxicologists keep a close watch of new developments in this field, in particular identification of early epigenetic markers for non-genotoxic carcinogenicity. Scientific collaborations between academia and industry will help to understand inter-individual variations in response to drug and toxin exposure to be able to distinguish between adverse and non-adverse epigenetic changes.
Seronegative Myasthenia Gravis and Graves’ Disease. Is there a link?
Authors: Polymeris A. , Karoutsou E. , Doumouchtsis K. 
Published: March 2012

AbstractGraves’ disease (GD) and myasthenia gravis (MG) are common autoimmune diseases but their coexistence is very rare. They may possibly share the same pathogenetic mechanisms. Recent research has shown the involvement of autoantibodies, lymphocytes, cytokines and chemokines in the pathogenesis of MG and GD. It appears that Th17 cell lineage is involved in autoimmune thyroid disease (AITD) and seems to be key factor in the development of both MG and GD.A 34-year-old male with seronegative myasthenia gravis due to thymic hyperplasia was diagnosed with also GD and opthalmopathy. Several diagnostic and therapeutic issues regarding the relevant literature are discussed.
Simulation Study of Biological Reference Points for Summer Flounder
Authors: Rothschild Brian J. , Jiao Yue , Hyun Saang‐Yoon 
Published: March 2012

AbstractThe biological reference pointFx%(i.e., the fishing mortality rate that maintains the spawning stock biomass per recruit atx% of its unfished value [wherexis usually set to 40]) is a commonly used proxy forFMSY(the fishing mortality rate that results in the maximum sustainable yield). However,Fx%is not in general equivalent toFMSY. To investigate the difference betweenFx%andFMSY, we developed a simple simulation model capable of representing the relationship between yield and fishing mortality, maximum spawning potential (%MSP), and the curvature of the stock–recruitment (S–R) curve (parameterized asβ) for a stock similar to summer flounderParalichthys dentatus(a high‐βspecies). The model demonstrates that the dynamic trajectories of the stock are heavily dependent onβ. The model confirmed the dependence of equilibrium yield onβand produced a specific relationship between the magnitude ofβand yield. A decision‐theoretic approach was used to suggest that settingxto 40 reduces yield and that smaller values ofxproduce greater yields for high‐βstocks. The analysis focuses attention on the fact that the choice ofFx%as a management tool places extreme reliance on the least known and understood component of fish population dynamics: the S–R relationship. Our conclusion (to use a value ofxconsiderably less than 40 to obtain MSY) was supported by (1) our simulation results, (2) averaging in a decision‐theoretic approach, (3) the correspondence of the traditionally computed biomass at the maximum sustainable yield with high values ofβ, and (4) the values ofxreported in the literature.
In Vivo Quantification of Cell Coupling in Plants with Different Phloem-Loading Strategies
Authors: Liesche Johannes , Schulz Alexander 
Published: March 2012

AbstractUptake of photoassimilates into the leaf phloem is the key step in carbon partitioning and phloem transport. Symplasmic and apoplasmic loading strategies have been defined in different plant taxa based on the abundance of plasmodesmata between mesophyll and phloem. For apoplasmic loading to occur, an absence of plasmodesmata is a sufficient but not a necessary criterion, as passage of molecules through plasmodesmata might well be blocked or restricted. Here, we present a noninvasive, whole-plant approach to test symplasmic coupling and quantify the intercellular flux of small molecules using photoactivation microscopy. Quantification of coupling between all cells along the prephloem pathways of the apoplasmic loader Vicia faba and Nicotiana tabacum showed, to our knowledge for the first time in vivo, that small solutes like sucrose can diffuse through plasmodesmata up to the phloem sieve element companion cell complex (SECCC). As expected, the SECCC was found to be symplasmically isolated for small solutes. In contrast, the prephloem pathway of the symplasmic loader Cucurbita maxima was found to be well coupled with the SECCC. Phloem loading in gymnosperms is not well understood, due to a profoundly different leaf anatomy and a scarcity of molecular data compared with angiosperms. A cell-coupling analysis for Pinus sylvestris showed high symplasmic coupling along the entire prephloem pathway, comprising at least seven cell border interfaces between mesophyll and sieve elements. Cell coupling together with measurements of leaf sap osmolality indicate a passive symplasmic loading type. Similarities and differences of this loading type with that of angiosperm trees are discussed.
Mannan-binding lectin (MBL)-associated serine protease-1 (MASP-1), a serine protease associated with humoral pattern-recognition molecules: normal and acute-phase levels in serum and stoichiometry of lectin pathway components
Authors: Thiel S , Jensen L , Degn S E , Nielsen H J , Gál P , Dobó J , Jensenius J C 
Published: March 2012

Summary
The pattern-recognition molecules mannan-binding lectin (MBL) and the three ficolins circulate in blood in complexes with MBL-associated serine proteases (MASPs). When MBL or ficolin recognizes a microorganism, activation of the MASPs occurs leading to activation of the complement system, an important component of the innate immune system. Three proteins are produced from the MASP1 gene: MASP-1 and MASP-3 and MAp44. We present an assay specific for MASP-1, which is based on inhibition of the binding of anti-MASP-1-specific antibody to MASP-1 domains coated onto microtitre wells. MASP-1 was found in serum in large complexes eluting in a position corresponding to ∼600 kDa after gel permeation chromatography in calcium-containing buffer and as monomers of ∼75 kDa in dissociating buffer. The concentration of MASP-1 in donor sera (n = 105) was distributed log-normally with a median value of 11 µg/ml (range 4–30 µg/ml). Serum and citrate plasma levels were similar, while the values in ethylenediamine tetraacetic acid plasma were slightly lower and in heparin plasma were 1·5 times higher than in serum. MASP-1 was present at adult level at 1 year of age, while it was 60% at birth. In normal healthy individuals the level of MASP-1 was stable throughout a 2-month period. After induction of an acute-phase reaction by operation we found an initial short decrease, concomitant with an increase in C-reactive protein levels, followed by an increase, doubling the MASP-1 concentration after 2 days. The present data prepare the ground for studies on the associations of MASP-1 levels with disease.
Revision of the population structuring of Illex argentinus (Castellanos, 1960) and a new interpretation based on modelling the spatio‐temporal environmental suitability for spawning and nursery
Authors: CRESPI‐ABRIL AUGUSTO C. , BARÓN PEDRO J. 
Published: March 2012

AbstractDuring the last 30 years, interpretation of the population structuring of Illex argentinus evolved from a single to a six‐stock model, in which stocks are characterized by having distinct spawning seasons, areas and migration patterns. It is assumed that major spawning activity occurs in discrete pulses along the outer‐shelf/slope off Argentina/southern Brazil during late‐fall/winter and that early life stages develop near the Brazil‐Malvinas Confluence (BMC). Nevertheless, there are inconsistencies in the delimitation of stocks and the interpretation of their life histories. Here, we developed a model based on records of seawater temperature and chlorophyll‐a concentration to establish the quality of different areas of the species’ geographic distribution as spawning and nursery grounds. Whereas the outer‐shelf/slope domain south of 37°S presents marked seasonal restrictions for embryonic development and breeding, coastal areas within 44°–28°S are highly suitable most of the year. Squid in pre‐spawning aggregations at the outer‐shelf/slope south of 41°S would invest less energy to reach equally suitable spawning areas at the coast than at the BMC. Findings of paralarvae, stranded juveniles and mature squid in coastal areas off northern Patagonia support the predictions of the model. Based on these results, the population structuring and reproductive–migration patterns are reviewed and a new interpretation is proposed: Illex argentinus spawns not only in discrete seasons and areas on the slope and mid/outer shelf, but also conducts quasi‐permanent spawning migrations to coastal areas, resulting in a more continuous pattern of recruitment than previously considered and in weak stock differentiation.
Functional diversity and trait–environment relationships of stream fish assemblages in a large tropical catchment
Authors: PEASE ALLISON A. , GONZÁLEZ‐DÍAZ ALFONSO A. , RODILES‐HERNÁNDEZ ROCÍO , WINEMILLER KIRK O. 
Published: March 2012

Summary1. The species composition of stream fish assemblages changes across the longitudinal fluvial gradient of large river basins. These changes may reflect both zonation in species distributions and environmental filtering of fish traits as stream environments change from the uplands to the lowlands of large catchments. Previous research has shown that taxonomic diversity generally increases in larger, lowland streams, and the River Continuum Concept, the River Habitat Template and other frameworks have provided expectations for what functional groups of fishes should predominate in certain stream types. However, studies addressing the functional trait composition of fish assemblages across large regions are lacking, particularly in tropical river basins.2. We examined functional trait–environment relationships and functional diversity of stream fish assemblages in the Río Grijalva Basin in southern Mexico. Traits linked to feeding, locomotion and life history strategy were measured in fishes from streams throughout the catchment, from highland headwaters to broad, lowland streams. Relationships between functional traits and environmental variables at local and landscape scales were examined using multivariate ordination, and the convex hull volume of trait space occupied by fish assemblages was calculated as a measure of functional diversity.3. Although there were a few exceptions, functional diversity of assemblages increased with species richness along the gradient from uplands to lowlands within the Grijalva Basin. Traits related to swimming, habitat preference and food resource use were associated with both local (e.g. substratum type, pool availability) and landscape‐scale (e.g. forest cover) environmental variables.4. Along with taxonomic structure and diversity, the functional composition of fish assemblages changed across the longitudinal fluvial gradient of the basin. Trait–environment relationships documented in this study partially confirmed theoretical expectations and revealed patterns that may help in developing a better understanding of general functional responses of fish assemblages to environmental change.
Information technology to support informal knowledge sharing
Authors: Davison Robert M. , Ou Carol X. J. , Martinsons Maris G. 
Published: March 2012

AbstractThe knowledge management (KM) literature largely focuses on the explicit and formal representation of knowledge in computer‐based KM systems. Informal KM practices are widespread, but less is known about them. This paper aims to redress this imbalance by exploring the use of interactive information technology (IT) applications for informal knowledge sharing (KS). We develop theoretical propositions to highlight the key facets of informal KS processes, and illustrate them through an interpretive case‐study analysis of KS in two public relations firms in China. We then discuss the implications of our findings for practice in both China and beyond. Finally, we recommend a research agenda to further investigate informal, relationship‐based knowledge sharing.
What makes blogging attractive to bloggers: a case of college‐level constituency users
Authors: Huang Y‐H. , Lo Y‐F. 
Published: March 2012

AbstractThis study presents a new perspective to facilitate learner‐centred weblog evaluation, based on content attractiveness, blogging support, and the value‐added service construct. A mixed method, combining fishbone diagram, fuzzy logic techniques, and the analytic hierarchy process, was conducted to identify further the criteria that attract bloggers to engage in blogging, based on user perspectives in a higher education context. Results indicate that the dimensions of content attractiveness and value‐added service for the benefit of students contributed two‐thirds of the overall weights. Respondents' appreciating a pleasant atmosphere is the first priority. Findings also indicated both similarities and differences among freshmen, non‐freshmen, and instructors and provide a valuable reference for various types of learning resources. This study made two contributions to research. First, the extracted weight values of the critical factors from the proposed hierarchical system framework serve as guidelines for enhancing the robustness and attractiveness of weblog content. Second, the evaluation process provided insights for managing weblog quality effectiveness to promote joyful interactions while exhibiting mutual connections.
Formal to informal learning with IT: research challenges and issues for e‐learning
Authors: Cox M.J. 
Published: March 2012

AbstractFor the purpose of clarity and consistency, the term e‐learning is used throughout the paper to refer to technology‐enhanced learning and information technology (IT) in teaching and learning. IT depicts computing and other IT resources. Research into e‐learning has changed in focus and breadth over the last four decades as a consequence of changing technologies, and changes in educational policies and practices. Although increasing numbers of young people have access to a wide range of IT technologies during their leisure activities, little is known about this impact on their learning. Much of the research evidence, to date, of students' informal uses of IT is about the frequency of use in different educational settings and the different types of IT uses occurring among learners at school and in the home. There is little evidence of the interrelationship between them.What makes researching e‐learning so difficult is the ever‐changing technology itself and the increasing access to IT resources in informal settings, changing the balance between formal and informal uses of e‐learning. This rebalancing not only results in a wider diversification of IT uses by learners but also a greater variability in their IT literacies and unknown variables such as the level of control of the learning activities, and contributions from third parties online. This paper reviews the wide range of technological and educational research changes that have taken place over the last 40 years, the affordances these provide, and the consequent implications for research methods and issues regarding investigating the impact of IT on formal and informal learning. Based on this analysis, strategies are proposed to help us achieve reliable research approaches and methods that take account of the eclectic nature of e‐learning and the growing influence of informal learning on e‐learning in education.
Varying conceptions of competence: an analysis of how health sciences educators define competence
Authors: Fernandez Nicolas , Dory Valerie , Ste‐Marie Louis‐Georges , Chaput Monique , Charlin Bernard , Boucher Andree 
Published: March 2012

Medical Education 2012: 46: 357–365Context  Current debate in medical education focuses on the nature of ‘competency‐based medical education’ (CBME) and whether or not it should be adopted. Many medical schools claim to run ‘competency‐based’ curricula, but the structure of their programmes can differ radically. A review of the existing CBME literature reveals that little attention has been paid to defining the concept of competence. A straightforward examination of what is meant by the term ‘competence’ is noticeably missing from the literature, despite its impact on medical training.Objectives  This paper aims to illustrate the varying conceptions of ‘competence’ by comparing and contrasting definitions provided in the health sciences education literature and discussing their respective impacts on medical education.Methods  A systematic review of recent publications in medical education journals published in English and French was conducted to extract definitions of competence or, if definitions were not explicitly stated, to derive the authors’ implicit conception of competence. A sample of 14 definitions from articles in the health sciences education field was studied using thematic analysis.Results  There is agreement that competence is composed of knowledge, skills and other components. Although agreement about the nature of these other components is lacking, attitudes and values are suggested to be essential ingredients of competence. Furthermore, a clear divergence in conceptions of how a competent person utilises these components is apparent. One view specifies that competence involves selecting components according to specific situations, as required. A second view places greater emphasis on the synergy that results from the use of a combination of components in a given situation.Conclusions  These conceptual distinctions have many implications for the way CBME is implemented. A conception of competence as the selection of components may lead to a greater emphasis, in a training setting, on the mastery of each component separately. A conception of competence as the use of a combination of components leads to greater emphasis on the synergy that results as they are deployed in clinical situations.
Towards an understanding of resilience and its relevance to medical training
Authors: Howe Amanda , Smajdor Anna , Stöckl Andrea 
Published: March 2012

Medical Education 2012:46: 349–356Objectives This article explores the concept of resilience and its potential relevance to medicine. It also looks at the dimensions of resilience and its ethical importance for effective professional practice, and considers whether a focus on resilience might be useful in medical training.Methods An applied literature search was conducted across the domains of education, ethics, psychology and sociology to answer the research question: ‘What is resilience and what might it mean for professional development in medical education?’ This article predominantly considers the findings in relation to training in undergraduate and postgraduate settings, although the literature is wide‐ranging and findings may be applicable elsewhere.Results Resilience is a dynamic capability which can allow people to thrive on challenges given appropriate social and personal contexts. The dimensions of resilience (which include self‐efficacy, self‐control, ability to engage support and help, learning from difficulties, and persistence despite blocks to progress) are all recognised as qualities that are important in clinical leaders. Much of what is deemed good practice in modern pedagogical approaches to medical training may support the development of resilience in adulthood, but this concept has rarely been used as a goal of professional development. More research is needed on the ways in which resilience can be recognised, developed and supported during and after clinical training.Conclusions Resilience is a useful and interesting construct which should be further explored in medical education practice and research.