476 research outputs found

    Chromatic (co)homology of finite general linear groups

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    We study the Morava EE-theory (at a prime pp) of BGLd(F)BGL_d(F), where FF is a finite field with ∣F∣=1(modp)|F|=1\pmod{p}. Taking all dd together, we obtain a structure with two products ×\times and ∙\bullet. We prove that it is a polynomial ring under ×\times, and that the module of ×\times-indecomposables inherits a ∙\bullet-product, and we describe the structure of the resulting ring. In the process, we prove many auxiliary structural results.Comment: Revised in response to referee's comments: added outline, additional context and references, and index of notation; various other minor change

    Method for assigning satellite lines to crystallographic sites in rare-earth crystals

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    We describe an experimental technique for associating the satellite lines in a rare-earth optical spectrum caused by a defect with the rare-earth ions in crystal sites around that defect. This method involves measuring the hyperfine splitting caused by

    The Common Assessment Framework (CAF) and the evaluation of Quality in a Public Service: Case Study of Academic Services of the University of Évora, Portugal

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    Society is more and more demanding on professional terms. Therefore, in order to achieve Excellence we need to go though processes of continuous improvement and we need to measure and to evaluate Quality which is increasingly seen as a competitive and distinguishing factor between institutions. And institutions from Public Sector like Universities are no exception. It’s urgent to evaluate their quality. But a question remains: how do we evaluate them? Why is it important? Should we evaluate the graduate and post-graduate degrees, the services that support all the University,…What? In Portugal it is compulsory to evaluate the quality of the degrees taught on a Higher Education Institution. For that purpose a set of legislation has been approved: Law n.º38/94 of 21st November, Decree-law n.º205/98 of 11th July and Law n.º1/2003 of 6th January. But if this is a compulsory procedure, shouldn’t the structures that support all the life of a Higher Education Institution also be evaluated? What happens if, for instance, the Academic Services don’t work properly or collapse? This service is considered as essential and fundamental on Higher Education Institutions

    A mathematical model characterising Achilles tendon dynamics in flexion

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    The purpose of this study is to acquire mechanistic knowledge of the gastrocnemius muscle-Achilles tendon complex behaviour during specific movements in humans through mathematical modelling. Analysis of this muscle-tendon complex was performed to see if already existing muscle-tendon models of other parts of the body could be applied to the leg muscles, especially the gastrocnemius muscle-Achilles tendon complex, and whether they could adequately characterise its behaviour. Five healthy volunteers were asked to take part in experiments where dorsiflexion and plantar flexion of the foot were studied. A model of the Achilles tendon-gastrocnemius muscle was developed, incorporating assumptions regarding the mechanical properties of the muscle fibres and the tendinous tissue in series. Ultrasound images of the volunteers, direct measurements and additional mathematical calculations were used to parameterise the model. Ground reaction forces, forces on specific joints and moments and angles for the ankle were obtained from a Vicon 3D motion capture system. Model validation was performed from the experimental data captured for each volunteer and from reconstruction of the movements of specific trajectories of the joints, muscles and tendons involved in those movements

    Body weight-based iodinated contrast immersion timing for human fetal postmortem microfocus computed tomography

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    Objectives The aim of this study was to evaluate the length of time required to achieve full iodination using potassium tri-iodide as a contrast agent, prior to human fetal postmortem microfocus computed tomography (micro-CT) imaging. Methods Prospective assessment of optimal contrast iodination was conducted across 157 human fetuses (postmortem weight range 2-298 g; gestational age range 12-37 weeks), following micro-CT imaging. Simple linear regression was conducted to analyse which fetal demographic factors could produce the most accurate estimate for optimal iodination time. Results Postmortem body weight (r2 = 0.6435) was better correlated with iodination time than gestational age (r2 = 0.1384), producing a line of best fit, y = [0.0304 × body weight (g)] − 2.2103. This can be simplified for clinical use whereby immersion time (days) = [0.03 × body weight (g)] − 2.2. Using this formula, for example, a 100-g fetus would take 5.2 days to reach optimal contrast enhancement. Conclusions The simplified equation can now be used to provide estimation times for fetal contrast preparation time prior to micro-CT imaging and can be used to manage service throughput and parental expectation for return of their fetus. Advances in knowledge A simple equation from empirical data can now be used to estimate preparation time for human fetal postmortem micro-CT imaging

    Status of Southeast Asia's marine sharks and rays

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    In Southeast Asia elasmobranchs are particularly threatened. We synthesized knowledge from the peer-reviewed and gray literature on elasmobranchs in the region, including their fisheries, status, trade, biology, and management. Our assessment included x species of sharkes and y species of rays. We found that 59% of assessed species are threatened with extinction and 72.5% are in decline; rays were more threatened than sharks. Research and conservation is complicated by the socioeconomic contexts of the countries, geopolitical issues in the South China Sea, and the overcapacity and multispecies nature of fisheries that incidentally capture elasmobranchs. The general paucity of data, funds, personnel, and enforcement hinders management. Reduced capacity in the general fishery sector and marine protected areas of sufficient size (for elasmobranchs and local enforcement capabilities) are among recommendations to strengthen conservation

    Routine placental histopathology findings from women testing positive for SARS-CoV-2 during pregnancy: Retrospective cohort comparative study

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    OBJECTIVE: To assess the impact of maternal Coronavirus disease 2019 (COVID-19) infection on placental histopathological findings in an unselected population and evaluate the potential effect on the fetus, including the possibility of vertical transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). DESIGN: Retrospective cohort comparative study of placental histopathological findings in patients with COVID-19, compared with controls. SETTING: During the COVID-19 pandemic, placentas were studied from women at University College Hospital London who reported and/or tested positive for COVID-19. POPULATION: Of 10 508 deliveries, 369 (3.5%) women had COVID-19 during pregnancy, with placental histopathology available for 244 women. METHODS: Retrospective review of maternal and neonatal characteristics, where placental analysis had been performed. This was compared with available, previously published, histopathological findings from placentas of unselected women. MAIN OUTCOME MEASURES: Frequency of placental histopathological findings and relevant clinical outcomes. RESULTS: Histological abnormalities were reported in 117 of 244 (47.95%) cases, with the most common diagnosis being ascending maternal genital tract infection. There was no statistically significant difference in the frequency of most abnormalities compared with controls. There were four cases of COVID-19 placentitis (1.52%, 95% CI 0.04%-3.00%) and one possible congenital infection, with placental findings of acute maternal genital tract infection. The rate of fetal vascular malperfusion (FVM), at 4.5%, was higher compared with controls (p = 0.00044). CONCLUSIONS: In most cases, placentas from pregnant women infected with SARS-CoV-2 virus do not show a significantly increased frequency of pathology. Evidence for transplacental transmission of SARS-CoV-2 is lacking from this cohort. There is a need for further study into the association between FVM, infection and diabetes
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