404 research outputs found

    Measurement of the electron charge asymmetry in inclusive W production in pp collisions at √s = 7 TeV in the CMS experiment.

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    In this thesis, two measurements of the electron charge asymmetry in inclusive W boson production with the CMS detector are presented. The measurements are obtained from proton-proton collision data with sqrt(s) = 7 TeV. The first measurement is performed with data corresponding to an integrated luminosity of 36 pb-1 collected by the CMS detector in 2010 and the second one uses data corresponding to 840 pb-1 collected during the first half of 2011. In proton-proton collisions, more W+ bosons are produced relative to W- due to the prevalence of up-type quarks with respect to down-type valence quarks in the proton. A measurement of this asymmetry as a function of the boson rapidity can provide valuable information on the u/d ratio within the proton. Since the boson rapidity cannot be directly measured due to the longitudinal momentum carried by the undetected neutrino, the asymmetry is measured as a function of the pseudorapidity of the charged lepton, in this case the electron, from the W decay. In both measurements, events are selected by requiring a single electron with tight selection criteria on quality of identification and measurement of the energy of the electron. The signal yield is extracted using extended maximum likelihood fits to the missing transverse energy spectrum using a set of reference template shapes for the signal, electroweak background and QCD background. The templates are obtained using Monte Carlo simulation, corrected with information from collision data events (for the signal and electroweak backgrounds), and a control sample of events obtained from an inverted selection (for the QCD background). In the first measurement the charge asymmetry is measured in 6 bins of the absolute value of the electron’s pseudorapidity and compared with predictions from theory. The statistical error ranges from 0.006 to 0.010. The increased amount of data in the second measurement allows the results to be presented in 11 bins of the absolute value of the electron’s pseudorapidity. The statistical error has been reduced and ranges from 0.003 to 0.004 and the global error is in the range 0.006 to 0.014.Open Acces

    Wireless Accelerometer for Neonatal MRI Motion Artifact Correction

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    A wireless accelerometer has been used in conjunction with a dedicated 3T neonatal MRI system installed on a Neonatal Intensive Care Unit to measure in-plane rotation which is a common problem with neonatal MRI. Rotational data has been acquired in real-time from phantoms simultaneously with MR images which shows that the wireless accelerometer can be used in close proximity to the MR system. No artifacts were observed on the MR images from the accelerometer or from the MR system on the accelerometer output. Initial attempts to correct the raw data using the measured rotational angles have been performed, but further work will be required to make a robust correction algorithm

    Flow cytometry-based evaluation of the bacterial removal efficiency of a blackwater reuse treatment plant and the microbiological changes in the associated non-potable distribution network

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    The study evaluated the changes in bacterial numbers across a full-scale membrane bioreactor (MBR) blackwater reuse system. Flow cytometry was used to quantify total and intact bacterial concentrations across the treatment train and during distribution of the recycled water. Membrane passage reduced bacterial numbers by up to 5-log units resulting in coliform-free permeate. A 2-log increase in bacterial cell concentration was subsequently observed after the granular activated carbon unit followed by a reduction in intact cells after chlorination, which corresponds to an overall intact bacteria removal of 3.4-log units. In the distribution network, the proportion of intact cells greatly depended on the free chlorine residual, with decreasing residual enabling regrowth. An initial target of 0.5 mg L−1 free chlorine ensured sufficient suppression of intact cells for up to 14 days (setting the time intervals for system flushes at times of low water usage). Bacterial regrowth was only observed when the free chlorine concentration was below 0.34 mg L−1. Such loss of residual chlorine mainly applied to distant points in the distribution network from the blackwater reuse treatment plant (BRTP). Flushing these network points for 5 min did not substantially reduce cell numbers. At points closer to the BRTP, on the other hand, flushing reduced cell numbers by up to 1.5-log units concomitant with a decreasing proportion of intact cells. Intact cell concentrations did not correlate with DOC, total nitrogen, or soluble reactive phosphate, but it was shown that dead biomass could be efficiently converted into new biomass within seven days

    Fetal Electrocardiogram (fECG) Gated MRI

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    We have developed a Magnetic Resonance Imaging (MRI)-compatible system to enable gating of a scanner to the heartbeat of a foetus for cardiac, umbilical cord flow and other possible imaging applications. We performed radiofrequency safety testing prior to a fetal electrocardiogram (fECG) gated imaging study in pregnant volunteers (n = 3). A compact monitoring device with advanced software capable of reliably detecting both the maternal electrocardiogram (mECG) and fECG simultaneously was modified by the manufacturer (Monica Healthcare, Nottingham, UK) to provide an external TTL trigger signal from the detected fECG which could be used to trigger a standard 1.5 T MR (GE Healthcare, Milwaukee, WI, USA) gating system with suitable attenuation. The MR scanner was tested by triggering rapidly during image acquisition at a typical fetal heart rate (123 beats per minute) using a simulated fECG waveform fed into the gating system. Gated MR images were also acquired from volunteers who were attending for a repeat fetal Central Nervous System (CNS) examination using an additional rapid cardiac imaging sequence triggered from the measured fECG. No adverse safety effects were encountered. This is the first time fECG gating has been used with MRI and opens up a range of new possibilities to study a developing foetus

    “That’s not what you expect to do as a doctor, you know, you don’t expect your patients to die.” Death as a learning experience for undergraduate medical students

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    BACKGROUND: Experiencing the death of a patient can be one of the most challenging aspects of clinical medicine for medical students. Exploring what students' learn from this difficult experience may contribute to our understanding of how medical students become doctors, and provide insights into the role a medical school may play in this development. This research examined medical students' responses of being involved personally in the death of a patient. METHOD: Ten undergraduate medical students were followed through their three years of clinical medical education. A total of 53 individual semi-structured interviews were conducted. Grounded theory analysis was used to analyze the data. RESULTS: Students illustrated a variety of experiences from the death of a patient. Three main themes from the analysis were derived: (i) Students’ reactions to death and their means of coping. Experiencing the death of a patient led to students feeling emotionally diminished, a decrease in empathy to cope with the emotional pain and seeking encouragement through the comfort of colleagues; (ii) Changing perceptions about the role of the doctor, the practice of medicine, and personal identity. This involved a change in students’ perceptions from an heroic curing view of the doctor’s role to a role of caring, shaped their view of death as a part of life rather than something traumatic, and resulted in them perceiving a change in identity including dampening their emotions; (iii) Professional environment, roles and responsibilities. Students began to experience the professional environment of the hospital by witnessing the ordinariness of death, understanding their role in formalizing the death of a patient, and beginning to feel responsible for patients. CONCLUSIONS: Along with an integrative approach to facilitate students learning about death, we propose staff development targeting a working knowledge of the hidden curriculum. Knowledge of the hidden curriculum, along with the role staff play in exercising this influence, is vital in order to facilitate translating the distressing experiences students face into worthwhile learning experiences. Finally, we argue that student learning about death needs to include learning about the social organization and working life of clinical settings, an area currently omitted from many medical education curricula

    Specimens, slips and systems: Daniel Solander and the classification of nature at the world's first public museum, 1753-1768.

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    The British Museum, based in Montague House, Bloomsbury, opened its doors on 15 January 1759, as the world's first state-owned public museum. The Museum's collection mostly originated from Sir Hans Sloane (1660-1753), whose vast holdings were purchased by Parliament shortly after his death. The largest component of this collection was objects of natural history, including a herbarium made up of 265 bound volumes, many of which were classified according to the late seventeenth-century system of John Ray (1627-1705). The 1750s saw the emergence of Linnaean binomial nomenclature, following the publication of Carl Linnaeus' Species Plantarum (1753) and Systema Naturae (1758). In order to adopt this new system for their collections, the Trustees of the British Museum chose to employ the Swedish naturalist and former student of Linnaeus, Daniel Solander (1733-1782) to reclassify the collection. Solander was ordered to devise a new system for classifying and cataloguing Sloane's natural history collection, which would allow both Linnaeans and those who followed earlier systems to access it. Solander's work was essential for allowing the British Museum to realize its aim of becoming a public centre of learning, adapting the collection to reflect the diversity of classificatory practices which were existent by the 1760s. This task engaged Solander until 1768, when he received an offer from Joseph Banks (1743-1820) to accompany him on HMS Endeavour to the Pacific

    Juxtaposing BTE and ATE – on the role of the European insurance industry in funding civil litigation

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    One of the ways in which legal services are financed, and indeed shaped, is through private insurance arrangement. Two contrasting types of legal expenses insurance contracts (LEI) seem to dominate in Europe: before the event (BTE) and after the event (ATE) legal expenses insurance. Notwithstanding institutional differences between different legal systems, BTE and ATE insurance arrangements may be instrumental if government policy is geared towards strengthening a market-oriented system of financing access to justice for individuals and business. At the same time, emphasizing the role of a private industry as a keeper of the gates to justice raises issues of accountability and transparency, not readily reconcilable with demands of competition. Moreover, multiple actors (clients, lawyers, courts, insurers) are involved, causing behavioural dynamics which are not easily predicted or influenced. Against this background, this paper looks into BTE and ATE arrangements by analysing the particularities of BTE and ATE arrangements currently available in some European jurisdictions and by painting a picture of their respective markets and legal contexts. This allows for some reflection on the performance of BTE and ATE providers as both financiers and keepers. Two issues emerge from the analysis that are worthy of some further reflection. Firstly, there is the problematic long-term sustainability of some ATE products. Secondly, the challenges faced by policymakers that would like to nudge consumers into voluntarily taking out BTE LEI

    Penilaian Kinerja Keuangan Koperasi di Kabupaten Pelalawan

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    This paper describe development and financial performance of cooperative in District Pelalawan among 2007 - 2008. Studies on primary and secondary cooperative in 12 sub-districts. Method in this stady use performance measuring of productivity, efficiency, growth, liquidity, and solvability of cooperative. Productivity of cooperative in Pelalawan was highly but efficiency still low. Profit and income were highly, even liquidity of cooperative very high, and solvability was good

    Search for stop and higgsino production using diphoton Higgs boson decays

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    Results are presented of a search for a "natural" supersymmetry scenario with gauge mediated symmetry breaking. It is assumed that only the supersymmetric partners of the top-quark (stop) and the Higgs boson (higgsino) are accessible. Events are examined in which there are two photons forming a Higgs boson candidate, and at least two b-quark jets. In 19.7 inverse femtobarns of proton-proton collision data at sqrt(s) = 8 TeV, recorded in the CMS experiment, no evidence of a signal is found and lower limits at the 95% confidence level are set, excluding the stop mass below 360 to 410 GeV, depending on the higgsino mass
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