990 research outputs found

    Central Exclusive Production in QCD

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    We investigate the theoretical description of the central exclusive production process, h1+h2 -> h1+X+h2. Taking Higgs production as an example, we sum logarithmically enhanced corrections appearing in the perturbation series to all orders in the strong coupling. Our results agree with those originally presented by Khoze, Martin and Ryskin except that the scale appearing in the Sudakov factor, mu=0.62 \sqrt{\hat{s}}, should be replaced with mu=\sqrt{\hat{s}}, where \sqrt{\hat{s}} is the invariant mass of the centrally produced system. We confirm this result using a fixed-order calculation and show that the replacement leads to approximately a factor 2 suppression in the cross-section for central system masses in the range 100-500 GeV.Comment: 41 pages, 19 figures; minor typos fixed; version published in JHE

    Facing medical care problems of victims of sexual violence in Goma/Eastern Democratic Republic of the Congo

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    <p>Abstract</p> <p>Background</p> <p>Since 1998, the Eastern Democratic Republic of the Congo has been torn by a military conflict. A particular atrocity of the war is widespread sexual violence.</p> <p>Methods</p> <p>In this combined retrospective analysis and prospective survey, we sought to identify hospital facilities and resources available to treat victims of sexual violence in Goma, the capital city of the North Kivu province.</p> <p>Results</p> <p>Of twenty-three acute care hospitals registered in the area of Goma, four (17%) regularly cared for victims of sexual violence. One hospital had all resources always available to appropriately care for victims of sexual violence. From Jan 2009 until Oct 2010, 7,048 females sought medical care because of physical or psychological sequelae from sexual violence in the four hospitals of Goma. Only half of the hospitals had physicians specialized in gynaecology or gynaecological surgery available. Similarly, anaesthetists and psychiatrists/psychologists were available in two (50%) and one (25%) hospital, respectively. Post-discharge care facilities, material resources, such as surgical and anaesthesiological equipment and drugs, were inconsistently available in the hospitals caring for sexually abused females. At one selected hospital, acyclovir and/or antibiotics were administered to 1,202 sexually abused females (89.5%), whereas post-exposure HIV prophylaxis and surgery because of vesico-vaginal fistula was provided to only 75 (5.6%) and 121 (9%) patients, respectively.</p> <p>Conclusions</p> <p>This study provides data that only few hospitals in Goma care for victims of sexual violence. In addition, these hospitals suffer from a relevant shortage of human and material resources to provide adequate care for sexually abused females. Aside from establishment of adequate protection strategies, steps must be taken to increase the availability of trained health care professionals and resources to provide adequate care for victims of sexual violence in Goma and the North Kivu province.</p

    Genetic and environmental influences on the stability of withdrawn behavior in children: A longitudinal, multi-informant twin study.

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    We examined the contribution of genetic and environmental influences on the stability of withdrawn behavior (WB) in childhood using a longitudinal multiple rater twin design. Maternal and paternal ratings on the withdrawn subscale of the Child Behavior Checklist (CBCL) were obtained from 14,889 families when the twins were 3, 7, 10 and 12 years old. A longitudinal psychometric model was fitted to the data and the fit of transmission and common factor models were evaluated for each variance component. WB showed considerable stability throughout childhood, with correlation coefficients ranging from about .30 for the 9-year time interval to .65 for shorter time intervals. Individual differences in WB as observed by the mother and the father were found to be largely influenced by genetic effects at all four time points, in both boys (50–66%) and girls (38–64%). Shared environmental influences explained a small to modest proportion (0–24%) of the variance at all ages and were slightly more pronounced in girls. Non-shared environmental influences were of moderate importance to the variance and slightly increased with age, from 22–28% at age 3 to 35–41% at age 12 years. The stability of WB was largely explained by genetic effects, accounting for 74% of stability in boys and 65% in girls. Shared environmental effects explained 7% (boys) and 17% (girls) of the behavioral stability. Most shared environmental effects were common to both raters, suggesting little influence of rater bias in the assessment of WB. The shared environmental effects common to both raters were best described by a common factor model, indicating that these effects are stable and persistent throughout childhood. Non-shared environmental effects accounted for the remaining covariance over time

    Second language user support

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    Computer users rarely experience entirely trouble-free interaction. The natural variety ofindividuals ensures that no software systems yield constantly fluent interaction for allusers. In consequence, software designers often strive to ameliorate this situation bybuilding 'user support' into their systems. User support can take different forms but,conventionally, each aims to assist the needy end-user by means of facilities directly supporting the performance of certain operations, or through supply of information thatadvises the user on available system functionality.The present paper briefly characterises a range of user support facilities before describingone requirement in greater detail. This aspect considers the needs of users whose mother-tongue is not English, but who are obliged to use English-based information systems. Inthis context, 'helping the user' must reasonably extend beyond mere advice on systemoperation to selective elucidation of information content. We regard this move as alogical extension of the user support concept, by seeking to address specific interactionneeds in a target user population. An example of this approach is described through aninformation system, in the domain of civil engineering, for native Chinese speakers ofEnglish

    Pre-divorce problems in 3-year-olds: a prospective study in boys and girls

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    Objective: We examined to what extent internalizing and externalizing problems at age 3 preceded and predicted parental divorce, and if divorce and the time lapse since divorce were related to internalizing and externalizing problems at age 12. Methods: Parental ratings of internalizing and externalizing problems were collected with the Child Behavior Checklist (CBCL) in a large sample (N = 6,426) of 3-yearold children. All these children were followed through the age of 12 years, at which parents completed the CBCL again, while teachers completed the Teacher's Report Form. Children whose parents divorced between age 3 and age 12 were compared with children whose families remained intact. Results: Girls whose parents divorced between ages 3 and 12 already showed more externalizing problems at age 3 than girls whose parents stayed married. Higher levels of externalizing problems in girls at age 3 predicted later parental divorce. Parental reports indicated that 12-year-olds with divorced parents showed more internalizing and externalizing problems than children with married parents. Levels of teacher-reported problems were not different between children with married versus divorced parents. However, children whose parents divorced between ages 3 and 12 showed more teacher-rated internalizing problems at age 12 when the divorce was more recent than when the divorce was less recent. Parental ratings of both internalizing and externalizing problems at age 12 were not associated with the time lapse since divorce. Conclusion: Externalizing problems in girls precede and predict later parental divorce. Post-divorce problems in children vary by raters, and may depend on the time lapse since divorce

    E46K-like α-synuclein mutants increase lipid interactions and disrupt membrane selectivity

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    Parkinson's disease (PD) is one of the most common neurodegenerative disorders and both genetic and histopathological evidence have implicated the ubiquitous presynaptic protein α-synuclein (αSyn) in its pathogenesis. Recent work has investigated how disrupting αSyn's interaction with membranes triggers trafficking defects, cellular stress, and apoptosis. Special interest has been devoted to a series of mutants exacerbating the effects of the E46K mutation (associated with autosomal dominant PD) through homologous E-to-K substitutions in αSyn's N-terminal region (i.e. E35K, E61K). Such E46K-like mutants have been shown to cause dopaminergic neuron loss and severe, yet L-DOPA-responsive, motor defects in mouse overexpression models, presenting enormous translational potential for PD and other "synucleinopathies". In this work, using a variety of biophysical techniques, we characterize the molecular pathology of E46K-like αSyn mutants by studying their structure and membrane-binding and remodeling abilities. We find that, although a slight increase in the mutants' avidity for synaptic vesicle-like membranes can be detected, most of their deleterious effects are connected to their complete disruption of αSyn's curvature selectivity. Indiscriminate binding can shift αSyn's subcellular localization away from its physiological interactants at the synaptic bouton toward trafficking vesicles and organelles, as observed in E46K-like cellular and murine models, as well as in human pathology. In conclusion, our findings suggest that a loss of curvature selectivity, rather than increased membrane affinity, could be the critical dyshomeostasis in synucleinopathies

    Investigating human audio-visual object perception with a combination of hypothesis-generating and hypothesis-testing fMRI analysis tools

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    Primate multisensory object perception involves distributed brain regions. To investigate the network character of these regions of the human brain, we applied data-driven group spatial independent component analysis (ICA) to a functional magnetic resonance imaging (fMRI) data set acquired during a passive audio-visual (AV) experiment with common object stimuli. We labeled three group-level independent component (IC) maps as auditory (A), visual (V), and AV, based on their spatial layouts and activation time courses. The overlap between these IC maps served as definition of a distributed network of multisensory candidate regions including superior temporal, ventral occipito-temporal, posterior parietal and prefrontal regions. During an independent second fMRI experiment, we explicitly tested their involvement in AV integration. Activations in nine out of these twelve regions met the max-criterion (A &lt; AV &gt; V) for multisensory integration. Comparison of this approach with a general linear model-based region-of-interest definition revealed its complementary value for multisensory neuroimaging. In conclusion, we estimated functional networks of uni- and multisensory functional connectivity from one dataset and validated their functional roles in an independent dataset. These findings demonstrate the particular value of ICA for multisensory neuroimaging research and using independent datasets to test hypotheses generated from a data-driven analysis

    Imaging response assessment for CNS germ cell tumours: consensus recommendations from the European Society for Paediatric Oncology Brain Tumour Group and North American Children's Oncology Group

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    Homogeneous and common objective disease assessments and standardised response criteria are important for better international clinical trials for CNS germ cell tumours. Currently, European protocols differ from those of North America (the USA and Canada) in terms of criteria to assess radiological disease response. An international working group of the European Society for Paediatric Oncology Brain Tumour Group and North American Children's Oncology Group was therefore established to review existing literature and current practices, identify major challenges regarding imaging assessment, and develop consensus recommendations for imaging response assessment for patients with CNS germ cell tumours. New clinical imaging standards were defined for the most common sites of CNS germ cell tumour and for the definition of locoregional extension. These new standards will allow the evaluation of response to therapy in patients with CNS germ cell tumours to be more consistent, and facilitate direct comparison of treatment outcomes across international studies

    Long-term outcome after anterior cervical discectomy without fusion

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    To retrospectively study the long-term outcome of patients after anterior cervical discectomy without fusion (ACD) compared to results published on the long-term outcome after ACD with fusion (ACDF). We reviewed the charts of all patients receiving ACD surgery between 1985 and 2000 to analyze the direct post-operative results as well as complications of the surgery. Moreover, 102 patients, randomly selected, were interviewed with the neck disability index to study possible persisting complaints up to 18 years after ACD surgery. A total of 551 Patients were identified. Two months post-operative follow up at the outpatient clinic revealed that 90.1% of patients were satisfied with the result of ACD surgery. At the time of the survey, this percentage had dropped to 67.6%. In addition, 20.6% and 11.8% had obtained moderate to severe complaints, respectively, in daily-life activities. Complaints were mainly localized in the neck region and occasionally provoked radiating pain in the arm. On the short term, ACD leads to a satisfied outcome. Over the longer term, patients report increasing complaints. The increase in complaints at the time of the survey may be the result of ongoing degenerative effects. Compared to published data on ACDF, there is no superiority of any fusion technique compared to ACD alone
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