702 research outputs found

    Discovery of the peculiar supernova 1998bw in the error box of GRB980425

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    The discovery of X-ray, optical and radio afterglows of gamma-ray bursts (GRBs) and the measurements of the distances to some of them have established that these events come from Gpc distances and are the most powerful photon emitters known in the Universe, with peak luminosities up to 10^52 erg/s. We here report the discovery of an optical transient, in the BeppoSAX Wide Field Camera error box of GRB980425, which occurred within about a day of the gamma-ray burst. Its optical light curve, spectrum and location in a spiral arm of the galaxy ESO 184-G82, at a redshift z = 0.0085, show that the transient is a very luminous type Ic supernova, SN1998bw. The peculiar nature of SN1998bw is emphasized by its extraordinary radio properties which require that the radio emitter expand at relativistical speed. Since SN1998bw is very different from all previously observed afterglows of GRBs, our discovery raises the possibility that very different mechanisms may give rise to GRBs, which differ little in their gamma-ray properties.Comment: Under press embargo at Nature (submitted June 10, 1998

    Towards the glueball spectrum from unquenched lattice QCD

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    We use a variational technique to study heavy glueballs on gauge configurations generated with 2+1 flavours of ASQTAD improved staggered fermions. The variational technique includes glueball scattering states. The measurements were made using 2150 configurations at 0.092 fm with a pion mass of 360 MeV. We report masses for 10 glueball states. We discuss the prospects for unquenched lattice QCD calculations of the oddballs.Comment: 19 pages, 4 tables and 8 figures. One figure added. Now matches the published versio

    Symmetry restoration at high-temperature in two-color and two-flavor lattice gauge theories

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    We consider the SU(2) gauge theory with Nf=2 flavors of Dirac fundamental fermions. We study the high-temperature behavior of the spectra of mesons, discretizing the theory on anisotropic lattices, and measuring the two-point correlation functions in the temporal direction as well as screening masses in various channels. We identify the (pseudo-)critical temperature as the temperature at which the susceptibility associated with the Polyakov loop has a maximum. At high temperature both the spin-1 and spin-0 sectors of the light meson spectra exhibit enhanced symmetry properties, indicating the restoration of both the global SU(4) and the axial U(1)A symmetries of the model

    Different aspects of emotional processes in apathy: Application of the French translated dimensional apathy scale

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    Apathy is a behavioural symptom that occurs in neuropsychiatric, neurological and neurodegenerative disease. It is defined as a lack of motivation and/or a quantitative reduction of goal-directed behaviour. Levy and Dubois Cerebral Cortex, 16(7), 916–928 (2006) proposed a triadic substructure of apathy and similar subtypes can be assessed using the Dimensional Apathy Scale (DAS), via the Executive, Emotional and Initiation subscales. The aim of this study was to translate the DAS in to French (f-DAS), examine its psychometric properties and the substructure of apathy using Confirmatory Factor Analysis (CFA). The results showed an acceptable internal consistency reliability of the f-DAS and a similar relationship to depression as in the original DAS development study. The CFA supported a triadic dimensional substructure of the f-DAS, similar to the original DAS but suggested a more complex substructure, specifically, two further processes of the Emotional apathy dimension relating to “Social Emotional” and “Individual Emotional” aspects of demotivation. To conclude, the f-DAS is a robust and reliable tool for assessing multidimensional apathy. Further research should explore the utility of the f-DAS in patients with neuropsychiatric diseases in view of social emotional aspects in apathy

    Why are family carers of people with dementia dissatisfied with general hospital care?: a qualitative study

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    Background Families and other carers report widespread dissatisfaction with general hospital care for confused older people. Methods We undertook a qualitative interviews study of 35 family carers of 34 confused older patients to ascertain their experiences of care on geriatric and general medical, and orthopaedic wards of a large English hospital. Transcripts were analysed using a grounded theory approach. Themes identified in interviews were categorised, and used to build a model explaining dissatisfaction with care. Results The experience of hospital care was often negative. Key themes were events (illness leading to admission, experiences in the hospital, adverse occurrences including deterioration in health, or perceived poor care); expectations (which were sometimes unrealistic, usually unexplored by staff, and largely unmet from the carers’ perspective); and relationships with staff (poor communication and conflict over care). Expectations were influenced by prior experience. A cycle of discontent is proposed. Events (or ‘crises’) are associated with expectations. When these are unmet, carers become uncertain or suspicious, which leads to a period of ‘hyper vigilant monitoring’ during which carers seek out evidence of poor care, culminating in challenge, conflict with staff, or withdrawal, itself a crisis. The cycle could be completed early during the admission pathway, and multiple cycles within a single admission were seen. Conclusion People with dementia who have family carers should be considered together as a unit. Family carers are often stressed and tired, and need engaging and reassuring. They need to give and receive information about the care of the person with dementia, and offered the opportunity to participate in care whilst in hospital. Understanding the perspective of the family carer, and recognising elements of the ‘cycle of discontent’, could help ward staff anticipate carer needs, enable relationship building, to pre-empt or avoid dissatisfaction or conflict

    A Social Identity Approach to Sport Psychology: Principles, Practice, and Prospects.

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    Drawing on social identity theory and self-categorization theory, we outline an approach to sport psychology that understands groups not simply as features of sporting contexts but rather as elements that can be, and often are, incorporated into a person's sense of self and, through this, become powerful determinants of their sport-related behavior. The underpinnings of this social identity approach are outlined, and four key lessons for sport that are indicative of the analytical and practical power of the approach are presented. These suggest that social identity is the basis for sports group (1) behavior, (2) formation and development, (3) support and stress appraisal, and (4) leadership. Building on recent developments within sport science, we outline an agenda for future research by identifying a range of topics to which the social identity approach could fruitfully contribute

    Disrupting Engineering Education

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    X-exome sequencing of 405 unresolved families identifies seven novel intellectual disability genes

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    X-linked intellectual disability (XLID) is a clinically and genetically heterogeneous disorder. During the past two decades in excess of 100 X-chromosome ID genes have been identified. Yet, a large number of families mapping to the X-chromosome remained unresolved suggesting that more XLID genes or loci are yet to be identified. Here, we have investigated 405 unresolved families with XLID. We employed massively parallel sequencing of all X-chromosome exons in the index males. The majority of these males were previously tested negative for copy number variations and for mutations in a subset of known XLID genes by Sanger sequencing. In total, 745 X-chromosomal genes were screened. After stringent filtering, a total of 1297 non-recurrent exonic variants remained for prioritization. Co-segregation analysis of potential clinically relevant changes revealed that 80 families (20%) carried pathogenic variants in established XLID genes. In 19 families, we detected likely causative protein truncating and missense variants in 7 novel and validated XLID genes (CLCN4, CNKSR2, FRMPD4, KLHL15, LAS1L, RLIM and USP27X) and potentially deleterious variants in 2 novel candidate XLID genes (CDK16 and TAF1). We show that the CLCN4 and CNKSR2 variants impair protein functions as indicated by electrophysiological studies and altered differentiation of cultured primary neurons from Clcn4−/− mice or after mRNA knock-down. The newly identified and candidate XLID proteins belong to pathways and networks with established roles in cognitive function and intellectual disability in particular. We suggest that systematic sequencing of all X-chromosomal genes in a cohort of patients with genetic evidence for X-chromosome locus involvement may resolve up to 58% of Fragile X-negative cases

    QCD and strongly coupled gauge theories : challenges and perspectives

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    We highlight the progress, current status, and open challenges of QCD-driven physics, in theory and in experiment. We discuss how the strong interaction is intimately connected to a broad sweep of physical problems, in settings ranging from astrophysics and cosmology to strongly coupled, complex systems in particle and condensed-matter physics, as well as to searches for physics beyond the Standard Model. We also discuss how success in describing the strong interaction impacts other fields, and, in turn, how such subjects can impact studies of the strong interaction. In the course of the work we offer a perspective on the many research streams which flow into and out of QCD, as well as a vision for future developments.Peer reviewe

    Fatal gemcitabine-induced pulmonary toxicity in metastatic gallbladder adenocarcinoma

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    Gemcitabine is a chemotherapy agent that may cause unpredictable side effects. In this report, we describe a fatal gemcitabine-induced pulmonary toxicity in a patient with gallbladder metastatic adenocarcinoma. A 72-year-old patient was submitted to an elective laparoscopic cholecystectomy, and a tubular adenocarcinoma in the gallbladder was incidentally diagnosed. CT scan and ultrasound before the surgery did not show any tumor. After the surgery a Pet scan was positive for a hot-spot in the left colon. The colonic lesion was conveniently removed and the histology evaluation confirmed the diagnosis of adenocarcinoma tubular. The patient was then submitted to three sections of 1,600 mg/m2 of gemcitabine with intervals of 1 week. Three weeks later he developed severe respiratory distress. A helicoidal CT scan showed diffuse and severe interstitial pneumonitis, and lung biopsy confirmed accelerated usual interstitial pneumonia consistent with drug-induced toxicity. The patient presented unfavorable evolution with progressive worsening of respiratory function, hypotension, and renal failure. He died 1 month later in spite of methylprednisolone pulse therapy, large spectrum antimicrobial therapy, and full support of respiratory, hemodynamic and renal systems. Gemcitabine-induced pulmonary toxicity is usually a dramatic condition. Physicians should suspect pulmonary toxicity in patients with respiratory distress after gemcitabine chemotherapy, mainly in elderly patients
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