611 research outputs found

    A Comparison of Machine Learning Methods for Cross-Domain Few-Shot Learning

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    We present an empirical evaluation of machine learning algorithms in cross-domain few-shot learning based on a fixed pre-trained feature extractor. Experiments were performed in five target domains (CropDisease, EuroSAT, Food101, ISIC and ChestX) and using two feature extractors: a ResNet10 model trained on a subset of ImageNet known as miniImageNet and a ResNet152 model trained on the ILSVRC 2012 subset of ImageNet. Commonly used machine learning algorithms including logistic regression, support vector machines, random forests, nearest neighbour classification, naïve Bayes, and linear and quadratic discriminant analysis were evaluated on the extracted feature vectors. We also evaluated classification accuracy when subjecting the feature vectors to normalisation using p-norms. Algorithms originally developed for the classification of gene expression data—the nearest shrunken centroid algorithm and LDA ensembles obtained with random projections—were also included in the experiments, in addition to a cosine similarity classifier that has recently proved popular in few-shot learning. The results enable us to identify algorithms, normalisation methods and pre-trained feature extractors that perform well in cross-domain few-shot learning. We show that the cosine similarity classifier and ℓ² -regularised 1-vs-rest logistic regression are generally the best-performing algorithms. We also show that algorithms such as LDA yield consistently higher accuracy when applied to ℓ² -normalised feature vectors. In addition, all classifiers generally perform better when extracting feature vectors using the ResNet152 model instead of the ResNet10 model

    Engaging Undergraduates in Science Research: Not Just About Faculty Willingness.

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    Despite the many benefits of involving undergraduates in research and the growing number of undergraduate research programs, few scholars have investigated the factors that affect faculty members' decisions to involve undergraduates in their research projects. We investigated the individual factors and institutional contexts that predict faculty members' likelihood of engaging undergraduates in their research project(s). Using data from the Higher Education Research Institute's 2007-2008 Faculty Survey, we employ hierarchical generalized linear modeling to analyze data from 4,832 science, technology, engineering, and mathematics (STEM) faculty across 194 institutions to examine how organizational citizenship behavior theory and social exchange theory relate to mentoring students in research. Key findings show that faculty who work in the life sciences and those who receive government funding for their research are more likely to involve undergraduates in their research project(s). In addition, faculty at liberal arts or historically Black colleges are significantly more likely to involve undergraduate students in research. Implications for advancing undergraduate research opportunities are discussed

    Paracetamol, NSAIDS and opioid analgesics for chronic low back pain: A network meta-analysis

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    This is a protocol for a Cochrane Review (Intervention). The objectives are as follows: To answer the clinical question: ‘what analgesic medicine shall I prescribe this patient with chronic low back pain to reduce their pain?’. The objectives are to determine the analgesic effects, safety, effect on function, and relative rank according to analgesic effect, safety and effect on function of a single course of opioid analgesics, NSAIDs or paracetamol or combinations of these medicines

    Staffing in postnatal units: is it adequate for the provision of quality care? Staff perspectives from a state-wide review of postnatal care in Victoria, Australia

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    BACKGROUND: State-wide surveys of recent mothers conducted over the past decade in Victoria, one state of Australia, have identified that women are consistently less satisfied with the care they received in hospital following birth compared with other aspects of maternity care. Little is known of caregivers' perspectives on the provision ofhospital postnatal care: how care is organised and provided in different hospitals; what constrains the provision of postnatal care (apart from funding) and what initiatives are being undertaken to improve service delivery. A state-widereview of organisational structures and processes in relation to the provision of hospital postnatal care in Victoria was undertaken. This paper focuses on the impact of staffing issues on the provision of quality postnatal care from the perspective of care providers. METHODS: A study of care providers from Victorian public hospitals that provide maternity services was undertaken. Datawere collected in two stages. Stage one: a structured questionnaire was sent to all public hospitals in Victoria that provided postnatal care (n = 73), exploring the structure and organisation of care (e.g. staffing, routine observations, policy framework and discharge planning). Stage two: 14 maternity units were selected and invited to participate in a more in-depth exploration of postnatal care. Thirty-eight key informant interviews were undertaken with midwives (including unit managers, associate unit managers and clinical midwives) and a medical practitioner from eachselected hospital. RESULTS: Staffing was highlighted as a major factor impacting on the provision of quality postnatal care. There were significant issues associated with inadequate staff/patient ratios; staffing mix; patient mix; prioritisation of birth suites over postnatal units; and the use of non-permanent staff. Forty-three percent of hospitals reported having only midwives (i.e. no non-midwives) providing postnatal care. Staffing issues impact on hospitals' ability to provide continuity of care. Recruitment and retention of midwives are significant issues, particularly in rural areas. CONCLUSION: Staffing in postnatal wards is a challenging issue, and varies with hospital locality and model of care. Staff/patient ratios and recruitment of midwives in rural areas are the two areas that appear to have the greatest negative impact on staffing adequacy and provision of quality care. Future research on postnatal care provision should include consideration of any impact on staff and staffing

    MHC-IIB Filament Assembly and Cellular Localization Are Governed by the Rod Net Charge

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    Actin-dependent myosin II molecular motors form an integral part of the cell cytoskeleton. Myosin II molecules contain a long coiled-coil rod that mediates filament assembly required for myosin II to exert its full activity. The exact mechanisms orchestrating filament assembly are not fully understood., negatively-charged regions of the coiled-coil were found to play an important role by controlling the intracellular localization of native MHC-IIB. The entire positively-charged region is also important for intracellular localization of native MHC-IIB.A correct distribution of positive and negative charges along myosin II rod is a necessary component in proper filament assembly and intracellular localization of MHC-IIB

    Computing Power and Sample Size for Case-Control Association Studies with Copy Number Polymorphism: Application of Mixture-Based Likelihood Ratio Test

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    Recent studies suggest that copy number polymorphisms (CNPs) may play an important role in disease susceptibility and onset. Currently, the detection of CNPs mainly depends on microarray technology. For case-control studies, conventionally, subjects are assigned to a specific CNP category based on the continuous quantitative measure produced by microarray experiments, and cases and controls are then compared using a chi-square test of independence. The purpose of this work is to specify the likelihood ratio test statistic (LRTS) for case-control sampling design based on the underlying continuous quantitative measurement, and to assess its power and relative efficiency (as compared to the chi-square test of independence on CNP counts). The sample size and power formulas of both methods are given. For the latter, the CNPs are classified using the Bayesian classification rule. The LRTS is more powerful than this chi-square test for the alternatives considered, especially alternatives in which the at-risk CNP categories have low frequencies. An example of the application of the LRTS is given for a comparison of CNP distributions in individuals of Caucasian or Taiwanese ethnicity, where the LRTS appears to be more powerful than the chi-square test, possibly due to misclassification of the most common CNP category into a less common category

    CpG-free plasmids confer reduced inflammation and sustained pulmonary gene expression.

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    Pulmonary delivery of plasmid DNA (pDNA)/cationic liposome complexes is associated with an acute unmethylated CG dinucleotide (CpG)-mediated inflammatory response and brief duration of transgene expression. We demonstrate that retention of even a single CpG in pDNA is sufficient to elicit an inflammatory response, whereas CpG-free pDNA vectors do not. Using a CpG-free pDNA expression vector, we achieved sustained (≥56 d) in vivo transgene expression in the absence of lung inflammation

    E-Cadherin Acts as a Regulator of Transcripts Associated with a Wide Range of Cellular Processes in Mouse Embryonic Stem Cells

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    We have recently shown that expression of the cell adhesion molecule E-cadherin is required for LIF-dependent pluripotency of mouse embryonic stem (ES) cells.In this study, we have assessed global transcript expression in E-cadherin null (Ecad-/-) ES cells cultured in either the presence or absence of LIF and compared these to the parental cell line wtD3.We show that LIF has little effect on the transcript profile of Ecad-/- ES cells, with statistically significant transcript alterations observed only for Sp8 and Stat3. Comparison of Ecad-/- and wtD3 ES cells cultured in LIF demonstrated significant alterations in the transcript profile, with effects not only confined to cell adhesion and motility but also affecting, for example, primary metabolic processes, catabolism and genes associated with apoptosis. Ecad-/- ES cells share similar, although not identical, gene expression profiles to epiblast-derived pluripotent stem cells, suggesting that E-cadherin expression may inhibit inner cell mass to epiblast transition. We further show that Ecad-/- ES cells maintain a functional β-catenin pool that is able to induce β-catenin/TCF-mediated transactivation but, contrary to previous findings, do not display endogenous β-catenin/TCF-mediated transactivation. We conclude that loss of E-cadherin in mouse ES cells leads to significant transcript alterations independently of β-catenin/TCF transactivation

    Bayesian analysis of Jolly-Seber type models; Incorporating heterogeneity in arrival and departure

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    We propose the use of finite mixtures of continuous distributions in modelling the process by which new individuals, that arrive in groups, become part of a wildlife population. We demonstrate this approach using a data set of migrating semipalmated sandpipers (Calidris pussila) for which we extend existing stopover models to allow for individuals to have different behaviour in terms of their stopover duration at the site. We demonstrate the use of reversible jump MCMC methods to derive posterior distributions for the model parameters and the models, simultaneously. The algorithm moves between models with different numbers of arrival groups as well as between models with different numbers of behavioural groups. The approach is shown to provide new ecological insights about the stopover behaviour of semipalmated sandpipers but is generally applicable to any population in which animals arrive in groups and potentially exhibit heterogeneity in terms of one or more other processes
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