5,022 research outputs found

    Data acquisition software for the CMS strip tracker

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    The CMS silicon strip tracker, providing a sensitive area of approximately 200 m2 and comprising 10 million readout channels, has recently been completed at the tracker integration facility at CERN. The strip tracker community is currently working to develop and integrate the online and offline software frameworks, known as XDAQ and CMSSW respectively, for the purposes of data acquisition and detector commissioning and monitoring. Recent developments have seen the integration of many new services and tools within the online data acquisition system, such as event building, online distributed analysis, an online monitoring framework, and data storage management. We review the various software components that comprise the strip tracker data acquisition system, the software architectures used for stand-alone and global data-taking modes. Our experiences in commissioning and operating one of the largest ever silicon micro-strip tracking systems are also reviewed

    Electron focusing, mode spectroscopy and mass enhancement in small GaAs/AlGaAs rings

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    A new electron focusing effect has been discovered in small single and coupled GaAs/AlGaAs rings. The focusing in the single ring is attributed solely to internal orbits. The focusing effect allows the ring to be used as a small mass spectrometer. The focusing causes peaks in the magnetoresistance at low fields, and the peak positions were used to study the dispersion relation of the one-dimensional magnetoelectric subbands. The electron effective mass increases with the applied magnetic field by a factor of 5050, at a magnetic field of 0.5T0.5T. This is the first time this increase has been measured directly. General agreement obtains between the experiment and the subband calculations for straight channels.Comment: 13 pages figures are available by reques

    Isolation of Human Photoreceptor Precursors via a Cell Surface Marker Panel from Stem Cell-derived Retinal Organoids and Fetal Retinae

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    Loss of photoreceptor cells due to retinal degeneration is one of the main causes of blindness in the developed world. Although there is currently no effective treatment, cell replacement therapy using stem-cell-derived photoreceptor cells may be a feasible future treatment option. In order to ensure safety and efficacy of this approach, robust cell isolation and purification protocols must be developed. To this end, we previously developed a biomarker panel for the isolation of mouse photoreceptor precursors from the developing mouse retina and mouse embryonic stem cell cultures. In the current study we applied this approach to the human pluripotent stem cell (hPSC) system, and identified novel biomarker combinations that can be leveraged for the isolation of human photoreceptors. Human retinal samples and hPSC-derived retinal organoid cultures were screened against 242 human monoclonal antibodies using a high through-put flow cytometry approach. We identified 46 biomarkers with significant expression levels in the human retina and hPSC differentiation cultures. Human retinal cell samples, either from fetal tissue or derived from embryonic and induced pluripotent stem cell cultures, were FAC-sorted using selected candidate biomarkers that showed expression in discrete cell populations. Enrichment for photoreceptors and exclusion of mitotically active cells was demonstrated by immunocytochemical analysis with photoreceptor-specific antibodies and Ki-67. We established a biomarker combination, which enables the robust purification of viable human photoreceptors from both human retinae and hPSC-derived organoid cultures. This article is protected by copyright. All rights reserved

    Simulating NIRS and MRS Measurements During Cerebral Hypoxia-Ischaemia in Piglets Using a Computational Model

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    We present a group analysis of the changes in cerebral haemodynamics, and the oxidation state of cytochrome-c-oxidase measured using broadband near-infrared spectroscopy (NIRS) and intracellular pH measured by phosphorous ((31)P) magnetic resonance spectroscopy (MRS) during and after cerebral hypoxia-ischaemia (HI) in 15 piglets. We use a previously published computational model of cerebral metabolism in the piglet [1] to integrate these measurements and simulate HI. We successfully simulate changes in cellular metabolism including shifts in intracellular pH observed in the piglet brain during HI. In this process, we optimise physiological parameters in the model identified through sensitivity analysis (such as the rate of glucose metabolism and intracellular lactate concentration), to fit simulated and measured data. The model fits the data reasonably and suggests a 20 % drop in glucose consumption, a ~65 % increase in lactate concentration and ~35 % drop in the cerebral metabolic rate of oxygen (CMRO₂) during HI

    Prevalence of Diabetes and High Risk for Diabetes Using A1C Criteria in the U.S. Population in 1988–2006

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    OBJECTIVE We examined prevalences of previously diagnosed diabetes and undiagnosed diabetes and high risk for diabetes using recently suggested A1C criteria in the U.S. during 2003–2006. We compared these prevalences to those in earlier surveys and those using glucose criteria. RESEARCH DESIGN AND METHODS In 2003–2006, the National Health and Nutrition Examination Survey included a probability sample of 14,611 individuals aged ≥12 years. Participants were classified on glycemic status by interview for diagnosed diabetes and by A1C, fasting, and 2-h glucose challenge values measured in subsamples. RESULTS Using A1C criteria, the crude prevalence of total diabetes in adults aged ≥20 years was 9.6% (20.4 million), of which 19.0% was undiagnosed (7.8% diagnosed, 1.8% undiagnosed using A1C ≥6.5%). Another 3.5% of adults (7.4 million) were at high risk for diabetes (A1C 6.0 to <6.5%). Prevalences were disproportionately high in the elderly. Age-/sex-standardized prevalence was more than two times higher in non-Hispanic blacks and Mexican Americans versus non-Hispanic whites for diagnosed, undiagnosed, and total diabetes (P < 0.003); standardized prevalence at high risk for diabetes was more than two times higher in non-Hispanic blacks versus non-Hispanic whites and Mexican Americans (P < 0.00001). Since 1988–1994, diagnosed diabetes generally increased, while the percent of diabetes that was undiagnosed and the percent at high risk of diabetes generally decreased. Using A1C criteria, prevalences of undiagnosed diabetes and high risk of diabetes were one-third that and one-tenth that, respectively, using glucose criteria. CONCLUSIONS Although A1C detects much lower prevalences than glucose criteria, hyperglycemic conditions remain high in the U.S., and elderly and minority groups are disproportionately affected. The A1C test has recently been recommended for diagnosing diabetes, based on a detailed analysis of its attributes by an international expert committee (1). Laboratory-measured A1C is now as accurate and precise as glucose assays due to improvements in instrumentation and standardization. A1C samples can be obtained at any time, require no patient preparation, and are relatively stable at room temperature after collection. A1C has substantially less biologic variability and is unaffected by acute effects of stress or illness. As a measure of long-term glycemic exposure, A1C has been shown to be better and more consistently correlated with retinopathy in the setting of observational studies and clinical trials in type 1 and type 2 diabetic patients, which have established widely accepted A1C treatment goals for diabetes. A cut point of ≥6.5% for the diagnosis of diabetes was recommended by the committee as optimal for detecting a level of retinopathy thought to be diabetes specific and not due to other conditions (e.g., hypertension). A limitation of A1C for diagnosis is that the committee could not define a specific intermediate threshold at which increased risk for diabetes clearly begins. While there is a continuum of risk even at values into the normal range, the committee suggested the range of ≥6.0 to <6.5% to represent the highest risk for progression to diabetes and one at which preventive measures might be implemented, with additional consideration of prevention efforts at lower levels in the presence of other risk factors. The committee hoped that its report would serve as a stimulus to the scientific community and professional organizations for considering the A1C assay for diagnosis of diabetes. A change in diagnostic criteria has important public health implications pertaining to the magnitude of the population with diabetes or at high risk of diabetes. This report examines the prevalence of diagnosed and undiagnosed diabetes and high risk of diabetes based on self-report and A1C criteria in the U.S. population during 2003–2006. Prevalences are compared with those using the A1C criteria in 1988–1994 and 1999–2002. Finally, we compare the concordance in prevalence of undiagnosed diabetes using the new A1C criteria to criteria based on fasting plasma glucose and 2-h plasma glucose from an oral glucose tolerance test (OGTT)

    Mitigating Case Mix Factors by Choice of Glycemic Control Performance Measure Threshold

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    OBJECTIVE—Performance measures are tools for assessing quality of care but may be influenced by patient factors. We investigated how currently endorsed performance measures for glycemic control in diabetes may be influenced by case mix composition. We assessed differences in A1C performance measure threshold attainment by case mix factors for A1C >9% and examined how lowering the threshold to A1C >8% or >7% changed these differences

    ‘Video Replay: Families, films and fantasy’ as a transformational text: Commentary on Valerie Walkerdine's ‘Video Replay’.

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    In this commentary I explore the significance of Valerie Walkerdine's paper ‘Video Replay: Families, Films and Fantasy’. I review its impact in 1986 and then discuss how some of its ideas about subjectivity and popular culture – specifically film - can be developed in the contemporary context. A recurring fantasy of Rocky II and its reception is that of social and psychological transformation. I address this theme by drawing on the work of Christopher Bollas to argue that Walkerdine's psychosocial analysis continues to facilitate, across a range of contexts, some of the transformational processes described in her article

    Searching for New Physics Through AMO Precision Measurements

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    We briefly review recent experiments in atomic, molecular, and optical physics using precision measurements to search for physics beyond the Standard Model. We consider three main categories of experiments: searches for changes in fundamental constants, measurements of the anomalous magnetic moment of the electron, and searches for an electric dipole moment of the electron.Comment: Prepared for Comments on AMO Physics at Physica Script

    Emergence of good conduct, scaling and Zipf laws in human behavioral sequences in an online world

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    We study behavioral action sequences of players in a massive multiplayer online game. In their virtual life players use eight basic actions which allow them to interact with each other. These actions are communication, trade, establishing or breaking friendships and enmities, attack, and punishment. We measure the probabilities for these actions conditional on previous taken and received actions and find a dramatic increase of negative behavior immediately after receiving negative actions. Similarly, positive behavior is intensified by receiving positive actions. We observe a tendency towards anti-persistence in communication sequences. Classifying actions as positive (good) and negative (bad) allows us to define binary 'world lines' of lives of individuals. Positive and negative actions are persistent and occur in clusters, indicated by large scaling exponents alpha~0.87 of the mean square displacement of the world lines. For all eight action types we find strong signs for high levels of repetitiveness, especially for negative actions. We partition behavioral sequences into segments of length n (behavioral `words' and 'motifs') and study their statistical properties. We find two approximate power laws in the word ranking distribution, one with an exponent of kappa-1 for the ranks up to 100, and another with a lower exponent for higher ranks. The Shannon n-tuple redundancy yields large values and increases in terms of word length, further underscoring the non-trivial statistical properties of behavioral sequences. On the collective, societal level the timeseries of particular actions per day can be understood by a simple mean-reverting log-normal model.Comment: 6 pages, 5 figure
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