8,526 research outputs found

    The persistence of vision: an analysis of continuity and change in conceptions of assessment within a teacher education program

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    Session 4 - Palawan 3Conference Theme: Assessment and the Challenge of GlobalizationThere is a significant and growing body of research that indicates teachers’ conceptions of assessment affect their professional relationship to and literacy in assessment. This study examines how a graduate-level course on educational assessment influenced the beliefs, values, and attitudes (i.e., conceptions) held by a small but diverse sample of New York City pre-service and practicing teachers about the nature and purpose of assessment. This study employed a qualitative, phenomenographic approach to establish an understanding of the systematic variations and consistencies in how participants experienced and understood assessment as teachers and as students. The prevailing conception of assessment participants had was negative. Although other conceptual categories emerged and developed between pre-and post-course interviews, this negative conception of assessment remained dominant in both pre- and postcourse interview sets, especially among practicing teachers. Both pre-service and practicing teachers indicated that assessment played a powerful role in personal history and pedagogy. The course appeared to be successful in contributing to teachers’ knowledge about assessment, but attitudes towards assessment remained largely unchanged and negative. The implications for assessment literacy, teacher education and practice posed by this disparity between change in knowledge and persistence in conceptions are explored.postprintThe 37th Annual Conference of the International Association of Educational Assessment (IAEA 2011), Mandaluyong City, Philippines, 23-28 October 2011

    What could be influencing older Ghanaians outpatient care utilization rate?

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    Objectives: Ghana’s population is rapidly aging and there may be healthcare access and utilization issues. This study investigates some of the issues that may influence outpatient care utilization rate among older Ghanaians. Methods: Cross-sectional wave 1 (2007-2010) data from WHO's Study on Global Ageing and Adult Health are used, and a sample of 1408 are analyzed. After multiple imputations of missing values, a negative binomial regression model is used to identify the association between outpatient care utilization rate and lifestyle activities. Results: The rate of outpatient care utilization is negatively associated with the rate of eating vegetables (β =0.0830, p < .001), fruits (β =0.0033, p < .05), moderate-exercise (β =0.4010, p < .001), moderate-work (β =0.2049, p < .001), walking/biking (β = 0.0436, p < .001), and positively associated with leisure hours ((β =0.0194, p < .001). Conclusion: To promote better aging situations of older adults in Ghana, poverty and poor education should be addressed as potential barriers to healthcare access. There is a need for policies that encourage healthier lifestyles for older Ghanaian’s health

    CD161(+) Tconv and CD161(+) Treg Share a Transcriptional and Functional Phenotype despite Limited Overlap in TCR beta Repertoire

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    Human regulatory T cells (Treg) are important in immune regulation, but can also show plasticity in specific settings. CD161 is a lectin-like receptor and its expression identifies an effector-like Treg population. Here, we determined how CD161+ Treg relate to CD161+ conventional T cells (Tconv). Transcriptional profiling identified a shared transcriptional signature between CD161+ Tconv and CD161+ Treg, which is associated with T helper (Th)1 and Th17 cells, and tissue homing, including high expression of gut-homing receptors. Upon retinoic acid (RA) exposure, CD161+ T cells were more enriched for CCR9+ and integrin α4+β7+ cells than CD161− T cells. In addition, CD161+ Tconv and CD161+ Treg were enriched at the inflamed site in autoimmune arthritis, and both CD161+ and CD161− Treg from the inflamed site were suppressive in vitro. CD161+ T cells from the site of autoimmune arthritis showed a diminished gut-homing phenotype and blunted response to RA suggesting prior imprinting by RA in the gut or at peripheral sites rather than during synovial inflammation. TCRβ repertoires of CD161+ and CD161− Tconv and Treg from blood showed limited overlap whereas there was clear overlap between CD161+ and CD161− Tconv, and CD161+ and CD161− Treg from the inflamed site suggesting that the inflamed environment may alter CD161 levels, potentially contributing to disease pathogenesis

    Effects of layer shift and yarn path variability on mechanical properties of a twill weave composite

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    Experimental and numerical analysis of a woven composite were performed in order to assess the effect of yarn path and layer shift variability on properties of the composite. Analysis of the geometry of a 12K carbon fibre 2×2 twill weave at the meso- and macro-scales showed the prevalence of the yarn path variations at the macro-scale over the meso-scale variations. Numerical analysis of yarn path variability showed that it is responsible for a Young’s modulus reduction of 0.5% and CoV of 1% which makes this type of variability in the selected reinforcement almost insignificant for an elastic analysis. Finite element analysis of damage propagation in laminates with layer shift showed good agreement with the experiments. Both numerical analysis and experiments showed that layer shift has a strong effect on the shape of the stress-strain curve. In particular, laminates with no layer shift tend to exhibit a kink in the stress-strain curve which was attributed solely to the layer configuration

    Application of field-portable-XRF for the determination of trace elements in deciduous leaves from a mine-impacted region

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    publisher: Elsevier articletitle: Application of field-portable-XRF for the determination of trace elements in deciduous leaves from a mine-impacted region journaltitle: Chemosphere articlelink: https://doi.org/10.1016/j.chemosphere.2018.06.110 content_type: article copyright: © 2018 Elsevier Ltd. All rights reserved

    Epithelial cell shedding and barrier function: a matter of life and death at the small intestinal villus tip

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    The intestinal epithelium is a critical component of the gut barrier. Composed of a single layer of intestinal epithelial cells (IECs) held together by tight junctions, this delicate structure prevents the transfer of harmful microorganisms, antigens, and toxins from the gut lumen into the circulation. The equilibrium between the rate of apoptosis and shedding of senescent epithelial cells at the villus tip, and the generation of new cells in the crypt, is key to maintaining tissue homeostasis. However, in both localized and systemic inflammation, this balance may be disturbed as a result of pathological IEC shedding. Shedding of IECs from the epithelial monolayer may cause transient gaps or microerosions in the epithelial barrier, resulting in increased intestinal permeability. Although pathological IEC shedding has been observed in mouse models of inflammation and human intestinal conditions such as inflammatory bowel disease, understanding of the underlying mechanisms remains limited. This process may also be an important contributor to systemic and intestinal inflammatory diseases and gut barrier dysfunction in domestic animal species. This review aims to summarize current knowledge about intestinal epithelial cell shedding, its significance in gut barrier dysfunction and host-microbial interactions, and where research in this field is directed

    Personalisation and recommender systems in digital libraries

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    Widespread use of the Internet has resulted in digital libraries that are increasingly used by diverse communities of users for diverse purposes and in which sharing and collaboration have become important social elements. As such libraries become commonplace, as their contents and services become more varied, and as their patrons become more experienced with computer technology, users will expect more sophisticated services from these libraries. A simple search function, normally an integral part of any digital library, increasingly leads to user frustration as user needs become more complex and as the volume of managed information increases. Proactive digital libraries, where the library evolves from being passive and untailored, are seen as offering great potential for addressing and overcoming these issues and include techniques such as personalisation and recommender systems. In this paper, following on from the DELOS/NSF Working Group on Personalisation and Recommender Systems for Digital Libraries, which met and reported during 2003, we present some background material on the scope of personalisation and recommender systems in digital libraries. We then outline the working group’s vision for the evolution of digital libraries and the role that personalisation and recommender systems will play, and we present a series of research challenges and specific recommendations and research priorities for the field

    Fatigue and Recovery Time Course After Female Soccer Matches: A Systematic Review And Meta-analysis.

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    BACKGROUND: This study aimed to analyze the extent of fatigue responses after female soccer matches and the ensuing recovery time course of performance, physiological, and perceptual responses. METHODS: Three databases (PubMed, Web of Science, and SPORTDiscus) were searched in October 2020 and updated in November 2021. Studies were included when participants were female soccer players, regardless of their ability level. Further, the intervention was an official soccer match with performance, physiological, or perceptual parameters collected pre- and post-match (immediately, 12 h, 24 h, 48 h, or 72 h-post). RESULTS: A total of 26 studies (n = 465 players) were included for meta-analysis. Most performance parameters showed some immediate post-match reduction (effect size [ES] = - 0.72 to - 1.80), apart from countermovement jump (CMJ; ES = - 0.04). Reduced CMJ performance occurred at 12 h (ES = - 0.38) and 24 h (ES = - 0.42) and sprint at 48 h post-match (ES = - 0.75). Inflammatory and immunological parameters responded acutely with moderate-to-large increases (ES = 0.58-2.75) immediately post-match. Creatine kinase and lactate dehydrogenase alterations persisted at 72 h post-match (ES = 3.79 and 7.46, respectively). Small-to-moderate effects were observed for increased cortisol (ES = 0.75) and reduced testosterone/cortisol ratio (ES = -0.47) immediately post-match, while negligible to small effects existed for testosterone (ES = 0.14) and estradiol (ES = 0.34). Large effects were observed for perceptual variables, with increased fatigue (ES = 1.79) and reduced vigor (ES = - 0.97) at 12 h post-match, while muscle soreness was increased immediately post (ES = 1.63) and at 24 h post-match (ES = 1.00). CONCLUSIONS: Acute fatigue exists following female soccer matches, and the performance, physiological, and perceptual parameters showed distinctive recovery timelines. Importantly, physical performance was recovered at 72 h post-match, whereas muscle damage markers were still increased at this time point. These timelines should be considered when planning training and match schedules. However, some caution should be advised given the small number of studies available on this population. REGISTRATION: The protocol for this systematic review was pre-registered on the International Prospective Register of Systematic Reviews (PROSPERO, Registration Number: CRD42021237857)

    Cellular adaptations to hypoxia and acidosis during somatic evolution of breast cancer

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    Conceptual models of carcinogenesis typically consist of an evolutionary sequence of heritable changes in genes controlling proliferation, apoptosis, and senescence. We propose that these steps are necessary but not sufficient to produce invasive breast cancer because intraductal tumour growth is also constrained by hypoxia and acidosis that develop as cells proliferate into the lumen and away from the underlying vessels. This requires evolution of glycolytic and acid-resistant phenotypes that, we hypothesise, is critical for emergence of invasive cancer. Mathematical models demonstrate severe hypoxia and acidosis in regions of intraductal tumours more than 100 m from the basement membrane. Subsequent evolution of glycolytic and acid-resistant phenotypes leads to invasive proliferation. Multicellular spheroids recapitulating ductal carcinoma in situ (DCIS) microenvironmental conditions demonstrate upregulated glucose transporter 1 (GLUT1) as adaptation to hypoxia followed by growth into normoxic regions in qualitative agreement with model predictions. Clinical specimens of DCIS exhibit periluminal distribution of GLUT-1 and Na+/H+ exchanger (NHE) indicating transcriptional activation by hypoxia and clusters of the same phenotype in the peripheral, presumably normoxic regions similar to the pattern predicted by the models and observed in spheroids. Upregulated GLUT-1 and NHE-1 were observed in microinvasive foci and adjacent intraductal cells. Adaptation to hypoxia and acidosis may represent key events in transition from in situ to invasive cancer

    Direct high-precision measurement of the magnetic moment of the proton

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    The spin-magnetic moment of the proton μp\mu_p is a fundamental property of this particle. So far μp\mu_p has only been measured indirectly, analysing the spectrum of an atomic hydrogen maser in a magnetic field. Here, we report the direct high-precision measurement of the magnetic moment of a single proton using the double Penning-trap technique. We drive proton-spin quantum jumps by a magnetic radio-frequency field in a Penning trap with a homogeneous magnetic field. The induced spin-transitions are detected in a second trap with a strong superimposed magnetic inhomogeneity. This enables the measurement of the spin-flip probability as a function of the drive frequency. In each measurement the proton's cyclotron frequency is used to determine the magnetic field of the trap. From the normalized resonance curve, we extract the particle's magnetic moment in units of the nuclear magneton μp=2.792847350(9)μN\mu_p=2.792847350(9)\mu_N. This measurement outperforms previous Penning trap measurements in terms of precision by a factor of about 760. It improves the precision of the forty year old indirect measurement, in which significant theoretical bound state corrections were required to obtain μp\mu_p, by a factor of 3. By application of this method to the antiproton magnetic moment μpˉ\mu_{\bar{p}} the fractional precision of the recently reported value can be improved by a factor of at least 1000. Combined with the present result, this will provide a stringent test of matter/antimatter symmetry with baryons.Comment: published in Natur
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