1,229 research outputs found

    Distribution of Oscillator Strengths for Recombination of Localised Excitons in Two Dimensions

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    We investigate the distribution of oscillator strengths for the recombination of excitons in a two dimensional sample, trapped in local minima of the confinement potential: the results are derived from a statistical topographic model of the potential. The predicted distribution of oscillator strengths is very different from the Porter-Thomas disribution which usually characterises disordered systems, and is notable for the fact that small oscillator strengths are extremely rare.Comment: Plain TeX, 11 pages, 2 of 3 Postscript figures, to appear in "Chaos, Solitons and Fractals" special issue on Mesoscopic Physics, July 199

    Viral suppression of multiple escape mutants by de novo CD8+ T cell responses in a human immunodeficiency virus-1 Infected elite suppressor

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    Elite suppressors or controllers (ES) are HIV-1 infected patients who maintain undetectable viral loads without treatment. While HLA-B*57-positive ES are usually infected with virus that is unmutated at CTL epitopes, a single, dominant variant containing CTL escape mutations is typically seen in plasma during chronic infection. We describe an ES who developed seven distinct and rare escape variants at an HLA-B*57-restricted Gag epitope over a five year period. Interestingly, he developed proliferative, de novo CTL responses that suppressed replication of each of these variants. These responses, in combination with low viral fitness of each variant, may contribute to sustained elite control in this ES

    Visuo-spatial ability in colonoscopy simulator training

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    Visuo-spatial ability is associated with a quality of performance in a variety of surgical and medical skills. However, visuo-spatial ability is typically assessed using Visualization tests only, which led to an incomplete understanding of the involvement of visuo-spatial ability in these skills. To remedy this situation, the current study investigated the role of a broad range of visuo-spatial factors in colonoscopy simulator training. Fifteen medical trainees (no clinical experience in colonoscopy) participated in two psycho-metric test sessions to assess four visuo-spatial ability factors. Next, participants trained flexible endoscope manipulation, and navigation to the cecum on the GI Mentor II simulator, for four sessions within 1 week. Visualization, and to a lesser degree Spatial relations were the only visuo-spatial ability factors to correlate with colonoscopy simulator performance. Visualization additionally covaried with learning rate for time on task on both simulator tasks. High Visualization ability indicated faster exercise completion. Similar to other endoscopic procedures, performance in colonoscopy is positively associated with Visualization, a visuo-spatial ability factor characterized by the ability to mentally manipulate complex visuo-spatial stimuli. The complexity of the visuo-spatial mental transformations required to successfully perform colonoscopy is likely responsible for the challenging nature of this technique, and should inform training- and assessment design. Long term training studies, as well as studies investigating the nature of visuo-spatial complexity in this domain are needed to better understand the role of visuo-spatial ability in colonoscopy, and other endoscopic techniques

    What support do frontline workers want? A qualitative study of health and social care workers' experiences and views of psychosocial support during the COVID-19 pandemic

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    Background: The COVID-19 pandemic has placed a significant burden on the mental health and wellbeing of frontline health and social care workers. The need to support frontline staff has been recognised. However, there is to date little research specifically on how best to support the mental health needs of frontline workers, and none on their own experiences and views about what might be most helpful. Aims: We set out to redress this research gap by qualitatively exploring UK frontline health and social care workers’ own experiences and views of psychosocial support during the pandemic. Method: Frontline health and social care workers were recruited purposively through social media and by snowball sampling via healthcare colleagues. Workers who volunteered to take part in the study were interviewed remotely following a semi-structured interview guide. Transcripts of the interviews were analysed by the research team following the principles of Reflexive Thematic Analysis. Results: We conducted 25 interviews with frontline workers from a variety of professional groups working in health and social care settings across the UK. Themes derived from our analysis showed that workers’ experiences and views about psychosocial support were complex. Peer support was many workers’ first line of support but could also be experienced as a burden. Workers were ambivalent about support shown by organisations, media and the public. Whilst workers valued psychological support services, there were many disparities in provision and barriers to access. Conclusions: The results of this study show that frontline health and social care workers are likely to need a flexible system of support including peer, organisational and professional support. More research is needed to fully unpack the structural, systemic and individual barriers to accessing psychosocial support. Greater collaboration, consultation and co-production of support services and their evaluation is warranted

    Time resolved pattern evolution in a large aperture laser

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    We have measured quasi-instantaneous transverse patterns in a broad aperture laser. Non-ordered patterns yielding to boundary determined regular structures in progressive time-integrated recording are observed. The linear analysis and numerical integration of the full Maxwell-Bloch equations allow us to interpret the features of the experiment. We show that this system being far from threshold cannot be fully understood with a perturbative model.Comment: 7 pages, 5 GIF figures . To be published in Phys. Rev. Let

    The association between intimate partner violence, alcohol and depression in family practice

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    Background: Depressive symptoms, intimate partner violence and hazardous drinking are common among patients attending general practice. Despite the high prevalence of these three problems; the relationship between them remains relatively unexplored. Methods: This paper explores the association between depressive symptoms, ever being afraid of a partner and hazardous drinking using cross-sectional screening data from 7667 randomly selected patients from a large primary care cohort study of 30 metropolitan and rural general practices in Victoria, Australia. The screening postal survey included the Center for Epidemiological Studies Depression Scale, the Fast Alcohol Screening Test and a screening question from the Composite Abuse Scale on ever being afraid of any intimate partner. Results: 23.9% met criteria for depressive symptoms. A higher proportion of females than males (20.8% vs. 7.6%) reported ever being afraid of a partner during their lifetime (OR 3.2, 95%CI 2.5 to 4.0) and a lower proportion of females (12%) than males (25%) were hazardous drinkers (OR 0.4; 95%CI 0.4 to 0.5); and a higher proportion of females than males (20.8% vs. 7.6%) reported ever being afraid of a partner during their lifetime (OR 3.2, 95%CI 2.5 to 4.0). Men and women who had ever been afraid of a partner or who were hazardous drinkers had on average higher depressive symptom scores than those who had never been afraid or who were not hazardous drinkers. There was a stronger association between depressive symptoms and ever been afraid of a partner compared to hazardous drinking for both males (ever afraid of partner; Diff 6.87; 95% CI 5.42, 8.33; p < 0.001 vs. hazardous drinking in last year; Diff 1.07, 95% CI 0.21, 1.94; p = 0.015) and females (ever afraid of partner; Diff 5.26; 95% CI 4.55, 5.97; p < 0.001 vs. hazardous drinking in last year; Diff 2.23, 95% CI 1.35, 3.11; p < 0.001), even after adjusting for age group, income, employment status, marital status, living alone and education level. Conclusions: Strategies to assist primary care doctors to recognise and manage intimate partner violence and hazardous drinking in patients with depression may lead to better outcomes from management of depression in primary care

    Detecting genetic regions associated with height in the native ponies of the British Isles by using high density SNP genotyping

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    Height is an important characteristic in the equine industry, although little is known about its genetic control in native British breeds of ponies. This study aimed to map QTL data with the withers height in four pony breeds native to the British Isles, including two different sections within Welsh Cobs. In this study, a genome-wide analysis approach using the Illumina Equine SNP50 Infinium BeadChip was applied to 105 ponies and cobs. Analysis identified 222 highly significant height-associated SNPs (P < 10-5), among which three SNPs on ECA9 have also been previously reported elsewhere. The highest number of significant SNPs associated to height in the native British horses were located on ECA1, ECA8 and ECA16
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