5,667 research outputs found

    Towards an Expert System for the Analysis of Computer Aided Human Performance

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    A Retrospective Cohort Study to Assess Patient and Physician Reported Outcome Measures After Decompressive Hemicraniectomy for Malignant Middle Cerebral Artery Stroke.

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    INTRODUCTION: Decompressive hemicraniectomy for malignant middle cerebral artery (MCA) infarction is known to reduce mortality. However, there are on-going concerns in terms of the quality of life in survivors. We aimed to examine the correlation between patient and physician reported outcome measures in decompressive hemicraniectomy. PATIENTS AND METHODS: We analyzed outcomes in 21 patients who underwent decompressive hemicraniectomy for malignant MCA infarction between September 2003 and August 2013 within a regional health system. Patient and physician reported outcome measures were collected at follow-up. These were Stroke Impact Scale (SIS) Version 3, modified Rankin Scale (mRS), National Hospital Seizure Severity Scale, Headache Impact Test and Patient Health Questionnaire for depression. RESULTS: There was a good correlation between physician and patient reported outcome measures. The Spearman's rank correlation coefficient between mRS and structured SIS Version 3 was -0.887 (p < 0.001); with unstructured SIS results, the correlation coefficient was -0.663 (p = 0.001). There was no statistically significant correlation between life worth and modified Rankin Scale: r = -0.3383 (p = 0.087). DISCUSSION: Our findings of a statistically significant correlation between mRS and SIS have not previously been reported in patients with this condition. These findings provide further information to inform patient and next of kin discussions regarding outcomes from decompressive hemicraniectomy in malignant MCA infarction

    Overview of ImageCLEFcoral 2019 task

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    Understanding the composition of species in ecosystems on a large scale is key to developing effective solutions for marine conservation, hence there is a need to classify imagery automatically and rapidly. In 2019, ImageCLEF proposed for the first time the ImageCLEFcoral task. The task requires participants to automatically annotate and localize benthic substrate (such as hard coral, soft coral, algae and sponge) in a collection of images originating from a growing, large-scale dataset from coral reefs around the world as part of monitoring programmes. In its first edition, five groups participated submitting 20 runs using a variety of machine learning and deep learning approaches. Best runs achieved 0.24 in the annotation and localisation subtask and 0.04 on the pixel-wise parsing subtask in terms of MAP 0.5 IoU scores which measures the Mean Average Precision (MAP) when using the performance measure of Intersection over Union (IoU) bigger to 0.5 of the ground truth

    Phase-Diverse Coherent Diffractive Imaging: High Sensitivity with Low Dose

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    This Letter demonstrates that coherent diffractive imaging (CDI), in combination with phase-diversity methods, provides reliable and artefact free high-resolution images. Here, using x rays, experimental results show a threefold improvement in the available image contrast. Furthermore, in conditions requiring low imaging dose, it is demonstrated that phase-diverse CDI provides a factor of 2 improvement in comparison to previous CDI techniques

    Nuclear tools for characterising radiological dispersion in complex terrain: evaluation of regulatory and emergency response models

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    Routine operations of a nuclear research reactor and its facilities offer opportunities for collection of rare environmental tracer datasets which can be used for atmospheric dispersion model evaluation studies. The HIFAR reactor near Sydney, Australia, routinely emits the radioactive noble gas Ar-41, and other radionuclides such as Xe-133 and Xe-135 are also emitted from nearby radiopharmaceutical production facilities. Despite extremely low emission levels of these gases, they are nevertheless detectable using state-of-the-art technology, and sensitive detectors have been placed at four locations in the surrounding region which features complex terrain. The high research potential of this unique dataset is illustrated in the current study, in which predictions from two atmospheric dispersion models used for emergency response are compared with Ar-41 peak observations from the detector network under a range of stability conditions, and long-term integrated data is also compared with a routine impact assessment model. © 2005, Inderscience Enterprises Ltd

    Actin cortex architecture regulates cell surface tension

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    Animal cell shape is largely determined by the cortex, a thin actin network underlying the plasma membrane in which myosin-driven stresses generate contractile tension. Tension gradients result in local contractions and drive cell deformations. Previous cortical tension regulation studies have focused on myosin motors. Here, we show that cortical actin network architecture is equally important. First, we observe that actin cortex thickness and tension are inversely correlated during cell-cycle progression. We then show that the actin filament length regulators CFL1, CAPZB and DIAPH1 regulate mitotic cortex thickness and find that both increasing and decreasing thickness decreases tension in mitosis. This suggests that the mitotic cortex is poised close to a tension maximum. Finally, using a computational model, we identify a physical mechanism by which maximum tension is achieved at intermediate actin filament lengths. Our results indicate that actin network architecture, alongside myosin activity, is key to cell surface tension regulation

    The evolution of multiple mating: Costs and benefits of polyandry to females and of polygyny to males

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    Polyandry is a paradox: why do females mate multiple times when a single ejaculate often provides enough sperm for lifetime egg production? Gowaty et al. addressed explanations for polyandry in Drosophila pseudoobscura from the perspective of hypotheses based on sex differences in costs of reproduction (CoR). Contrary to CoR, Gowaty et al. showed that (1) a single ejaculate was inadequate for lifetime egg production; (2) polyandry provided fitness benefits to females beyond provision of adequate sperm and (3) fitness benefits of polyandry were not offset by costs. Here, I discuss predictions of the ad hoc hypotheses of CoR and three alternative hypotheses to CoR to facilitate a discussion and further development of a strong inference approach to experiments on the adaptive significance of polyandry for females. Each of the hypotheses makes testable predictions; simultaneous tests of the predictions will provide a strong inference approach to understanding the adaptive significance of multiple mating. I describe a sex-symmetric experiment meant to evaluate variation in fitness among lifelong virgins (V); monogamous females and males with one copulation (MOC); monogamous females and males with multiple copulations (MMC); PAND, polyandrous females; and PGYN, polygynous males. Last, I recommend the study of many different species, while taking care in choice of study species and attention to the assumptions of specific hypotheses. I particularly urge the study of many more Drosophila species both in laboratory and the wild to understand the “nature of flies in nature,” where opportunities and constraints mold evolutionary responses

    Editorial: Biodiversity, Connectivity and Ecosystem Function Across the Clarion-Clipperton Zone: A Regional Synthesis for an Area Targeted for Nodule Mining

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    The Clarion Clipperton Zone (CCZ) in the equatorial Pacific Ocean is a vast region of abyssal plains and hills, polymetallic nodule fields, and seamounts. Because of the cobalt, nickel and copper content of polymetallic nodules in this region, the CCZ is targeted for deep-seabed mining. In order to safeguard seafloor biodiversity and ecosystem functions across the region in the event of mining, the International Seabed Authority (ISA) in 2012 designated nine 400×400 km no-mining areas, called Areas of Particular Environmental Interest (APEIs) (Wedding et al., 2013). The APEIs were designed based on environmental correlates of biodiversity and ecosystem function to be representative of the full range of seafloor habitats and communities potentially impacted by nodule-mining activities within the licensed mining exploration areas spanning the CCZ (Wedding et al., 2013). Since APEI establishment in 2012, a substantial number of research expeditions have collected biodiversity and ecosystem-function data within the CCZ. These expeditions mainly focused on individual contract areas or APEIs. To date, there have been limited efforts to synthesize data at the regional level, which is critical for the further development of ISA’s CCZ Environmental Management Plan (EMP). The Deep CCZ Biodiversity Synthesis Workshop was conducted in October 2019 with a new focus on the CCZ EMP, specifically to (1) compile recent deep-sea ecosystem data from across the CCZ, (2) synthesize patterns of seafloor biodiversity, ecosystem functions, and potential environmental drivers, and (3) assess the representativity of the APEIs for areas in the CCZ targeted for polymetallic nodule mining (International Seabed Authority, 2020). This Special Research Topic of Frontiers in Marine Science draws together scientific papers derived from the workshop, as well as others elucidating environmental variability and deep-sea biodiversity across the region

    VEZF1 elements mediate protection from DNA methylation

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    There is growing consensus that genome organization and long-range gene regulation involves partitioning of the genome into domains of distinct epigenetic chromatin states. Chromatin insulator or barrier elements are key components of these processes as they can establish boundaries between chromatin states. The ability of elements such as the paradigm &#946;-globin HS4 insulator to block the range of enhancers or the spread of repressive histone modifications is well established. Here we have addressed the hypothesis that a barrier element in vertebrates should be capable of defending a gene from silencing by DNA methylation. Using an established stable reporter gene system, we find that HS4 acts specifically to protect a gene promoter from de novo DNA methylation. Notably, protection from methylation can occur in the absence of histone acetylation or transcription. There is a division of labor at HS4; the sequences that mediate protection from methylation are separable from those that mediate CTCF-dependent enhancer blocking and USF-dependent histone modification recruitment. The zinc finger protein VEZF1 was purified as the factor that specifically interacts with the methylation protection elements. VEZF1 is a candidate CpG island protection factor as the G-rich sequences bound by VEZF1 are frequently found at CpG island promoters. Indeed, we show that VEZF1 elements are sufficient to mediate demethylation and protection of the APRT CpG island promoter from DNA methylation. We propose that many barrier elements in vertebrates will prevent DNA methylation in addition to blocking the propagation of repressive histone modifications, as either process is sufficient to direct the establishment of an epigenetically stable silent chromatin stat
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