740 research outputs found

    Statistical methods for the analysis of the genetics of gene expression

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    Two-dimensional shear modulus of a Langmuir foam

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    We deform a two-dimensional (2D) foam, created in a Langmuir monolayer, by applying a mechanical perturbation, and simultaneously image it by Brewster angle microscopy. We determine the foam stress tensor (through a determination of the 2D gas-liquid line tension, 2.35 ±\pm 0.4 pJ\cdotm1^{-1}) and the statistical strain tensor, by analyzing the images of the deformed structure. We deduce the 2D shear modulus of the foam, μ=38±3nNm1\mu= 38 \pm 3 \mathrm{nN}\cdot \mathrm{m}^{-1}. The foam effective rigidity is predicted to be 35±3nNm1 35 \pm 3 \mathrm {nN}\cdot \mathrm {m}^{- 1}, which agrees with the value 37.5±0.8nNm137.5 \pm 0.8 \mathrm {nN}\cdot \mathrm {m}^{-1} obtained in an independent mechanical measurement.Comment: submitted May 12, 2003 ; resubmitted Sept 9, 200

    MACAT—microarray chromosome analysis tool

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    By linking differential gene expression to the chromosomal localization of genes, one can investigate microarray data for characteristic patterns of expression phenomena involving sizeable parts of specific chromosomes. We have implemented a statistical approach for identifying significantly differentially expressed chromosome regions. We demonstrate the applicability of the approach on a publicly available data set on acute lymphocytic leukemia

    Surface nanobubbles on the rare earth fluorcarbonate mineral synchysite

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    This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this recordData availability: Original data from this publication is available via open access at the British Geological Survey National Geoscience Data Centre, United Kingdom (NGDC)Surface nanobubbles have been identified to play an important role in a range of industries from mineral processing to food science. The formation of surface nanobubbles is of importance for mineral processing in the extraction of complex ores, such as those containing rare earth elements. This is due to the way minerals are extracted utilising froth flotation. In this study, surface nanobubbles were imaged using non-contact atomic force microscopy on a polished cross section containing rare earth minerals. Nanobubbles were found on synchysite under reagent conditions expected to induce hydrophobicity in rare earth minerals, which is required for efficient processing. Synchysite –(Ce)is a rare earth fluorcarbonate mineral containing over 30% rare earth elements. Relatively little research has been conducted on synchysite, with only a few papers on its surface behaviour and flotation. The resulting nanobubbles were analysed and showed an average contact angle of 24° ± 8. These are in line with contact angles found on dolomite and galena by previous studies.Mkango Resources Ltd

    Detecting Candida albicans in Human Milk

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    Procedures for diagnosis of mammary candidosis, including laboratory confirmation, are not well defined. Lactoferrin present in human milk can inhibit growth of Candida albicans, thereby limiting the ability to detect yeast infections. The inhibitory effect of various lactoferrin concentrations on the growth of C. albicans in whole human milk was studied. The addition of iron to the milk led to a two- to threefold increase in cell counts when milk contained 3.0 mg of lactoferrin/ml and markedly reduced the likelihood of false-negative culture results. This method may provide the necessary objective support needed for diagnosis of mammary candidosis

    Comparison of Different Parallel Implementations of the 2+1-Dimensional KPZ Model and the 3-Dimensional KMC Model

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    We show that efficient simulations of the Kardar-Parisi-Zhang interface growth in 2 + 1 dimensions and of the 3-dimensional Kinetic Monte Carlo of thermally activated diffusion can be realized both on GPUs and modern CPUs. In this article we present results of different implementations on GPUs using CUDA and OpenCL and also on CPUs using OpenCL and MPI. We investigate the runtime and scaling behavior on different architectures to find optimal solutions for solving current simulation problems in the field of statistical physics and materials science.Comment: 14 pages, 8 figures, to be published in a forthcoming EPJST special issue on "Computer simulations on GPU

    Clinical lactation practice: 20 years of evidence

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    Lactation consultants depend on a vast multidisciplinary knowledge base to support their practices. To coincide with the 20-year anniversary of the International Lactation Consultant Association, the authors sought to highlight the knowledge base to demonstrate how practice has been affected. Using standard databases, they extracted English-language scientific literature related to breastfeeding and maternal and infant health outcomes; factors associated with breastfeeding initiation, exclusivity, and duration; lactation physiology; common breastfeeding challenges; breastfeeding practices within vulnerable populations; health professional support of breastfeeding; and breastfeeding practices in developing countries of Africa. Summaries of research are provided to demonstrate scientific method and knowledge evolution. As the knowledge of the biological, behavioral, and environmental factors that affect breastfeeding continues to grow, researchers and lactation consultants will identify additional research areas. Thus, the cycle of describing and explaining phenomena, testing interventions to improve practice, and ultimately improving breastfeeding outcomes worldwide will continue

    A century of coping with environmental and ecological changes via compensatory biomineralization in mussels

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    Accurate biological models are critical to predict biotic responses to climate change and human‐caused disturbances. Current understanding of organismal responses to change stems from studies over relatively short timescales. However, most projections lack long‐term observations incorporating the potential for transgenerational phenotypic plasticity and genetic adaption, the keys to resistance. Here, we describe unexpected temporal compensatory responses in biomineralization as a mechanism for resistance to altered environmental conditions and predation impacts in a calcifying foundation species. We evaluated exceptional archival specimens of the blue mussel Mytilus edulis collected regularly between 1904 and 2016 along 15 km of Belgian coastline, along with records of key environmental descriptors and predators. Contrary to global‐scale predictions, shell production increased over the last century, highlighting a protective capacity of mussels for qualitative and quantitative trade‐offs in biomineralization as compensatory responses to altered environments. We also demonstrated the role of changes in predator communities in stimulating unanticipated biological trends that run contrary to experimental predictive models under future climate scenarios. Analysis of archival records has a key role for anticipating emergent impacts of climate change

    An MRI evaluation of grey matter damage in African Americans with MS

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    Objective: Multiple sclerosis (MS) is less prevalent in African Americans (AAs) than Caucasians (CAs) but in the former the disease course tends to be more severe. In order to clarify the MRI correlates of disease severity in AAs, we performed a multimodal brain MRI study to comprehensively assess the extent of grey matter (GM) damage and the degree of functional adaptation to structural damage in AAs with MS. Methods: In this cross-sectional study, we characterized GM damage in terms of focal lesions and volume loss and functional adaptation during the execution of a simple motor task on a sample of 20 AAs and 20 CAs with MS and 20 healthy controls (CTRLs). Results: In AAs, we observed a wider range of EDSS scores than CAs, with multisystem involvement being more likely in AAs (p < 0.01). While no significant differences were detected in lesion loads and global brain volumes, AAs showed regional atrophy in the posterior lobules of cerebellum, temporo-occipital and frontal regions in comparison with CAs (p < 0.01), with cerebellar atrophy being the best metric in differentiating AAs from CAs (p = 0.007, AUC = 0.96 and p = 0.005, AUC = 0.96, respectively for right and left cerebellar clusters). In AAs, the functional analysis of cortical activations showed an increase in task-related activation of areas involved in high level processing and a decreased activation in the medial prefrontal cortex compared to CAs. Interpretation: In our study, the direct comparison of AAs and CAs points to cerebellar atrophy as the main difference between subgroups
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