606 research outputs found

    Soliton core filling in superfluid Fermi gases with spin-imbalance

    Full text link
    In this paper the properties of dark solitons in superfluid Fermi gases with spin-imbalance are studied by means of a recently developed effective field theory [S. N. Klimin, J. Tempere, G. Lombardi, J. T. Devreese, Eur. Phys. J. B 88, 122 (2015)] suitable to describe the BEC-BCS crossover in ultracold gases in an extended range of temperatures as compared to the usual Ginzburg-Landau treatments. The spatial profiles for the total density and for the density of the excess-spin component, and the changes of their properties across the BEC-BCS crossover are examined in different conditions of temperature and imbalance. The presence of population imbalance is shown to strongly affect the structure of the soliton excitation by filling its core with unpaired atoms. This in turn influences the dynamical properties of the soliton since the additional particles in the core have to be dragged along thus altering the effective mass.Comment: 9 pages, 9 figure

    Influence of osmolarity of the growth medium on the outer membrane protein pattern of Escherichia coli

    Get PDF
    The starting point for this paper is Roland Barthesā€™ polemical foreword to his Sur Racine (published in April 1963), in which Barthes views Racine as the Ā«Ā degree zero of the critical objectĀ Ā» ā€“ an expression which should be placed in the context of his many interrogations regarding the Ā«Ā classicalĀ Ā» authors of the 19th century. I will attempt to show how this postulate is transformed into a significant epistemic interrogation at the core of the Barthesian theory of language and literature. To achieve this, I will look into the reasons for Barthesā€™ decision to convey the Racinian language and its tragic universe through a Ā«Ā deliberately closed analysisĀ Ā» of the dramatistā€™s plays and the reconstitution of a Racinian anthropology, Ā«Ā both structural and analyticalĀ Ā», as well as psychoanalitycal. This reflection will be based on the theoretical and critical dialogue which can nowadays be construed between Sur Racine, the modern tragic sense of Berenice, and the contemporary production of this play staged by the Portuguese director Carlos Pimenta (2005)

    Mass fatality management following the South Asian tsunami disaster: case studies in Thailand, Indonesia, and Sri Lanka.

    Get PDF
    BACKGROUND: Following natural disasters, mismanagement of the dead has consequences for the psychological well-being of survivors. However, no technical guidelines currently exist for managing mass fatalities following large natural disasters. Existing methods of mass fatality management are not directly transferable as they are designed for transport accidents and acts of terrorism. Furthermore, no information is currently available about post-disaster management of the dead following previous large natural disasters. METHODS AND FINDINGS: After the tsunami disaster on 26 December 2004, we conducted three descriptive case studies to systematically document how the dead were managed in Thailand, Indonesia, and Sri Lanka. We considered the following parameters: body recovery and storage, identification, disposal of human remains, and health risks from dead bodies. We used participant observations as members of post-tsunami response teams, conducted semi-structured interviews with key informants, and collected information from published and unpublished documents. Refrigeration for preserving human remains was not available soon enough after the disaster, necessitating the use of other methods such as dry ice or temporary burial. No country had sufficient forensic capacity to identify thousands of victims. Rapid decomposition made visual identification almost impossible after 24-48 h. In Thailand, most forensic identification was made using dental and fingerprint data. Few victims were identified from DNA. Lack of national or local mass fatality plans further limited the quality and timeliness of response, a problem which was exacerbated by the absence of practical field guidelines or an international agency providing technical support. CONCLUSIONS: Emergency response should not add to the distress of affected communities by inappropriately disposing of the victims. The rights of survivors to see their dead treated with dignity and respect requires practical guidelines and technical support. Mass fatality management following natural disasters needs to be informed by further field research and supported by a network of regional and international forensic institutes and agencies

    A dynamic deep sleep stage in Drosophila

    Get PDF
    Howmight one determine whether simple animals such as flies sleep in stages? Sleep inmammalsis a dynamic process involving different stages of sleep intensity, and these are typically associated with measurable changes in brain activity (Blake and Gerard, 1937; Rechtschaffen and Kales, 1968; Webb and Agnew, 1971). Evidence for different sleep stages in invertebrates remains elusive, even though it has been well established that many invertebrate species require sleep (Campbell and Tobler, 1984; Hendricks et al., 2000; Shaw et al., 2000; Sauer et al., 2003). Here we used electrophysiology and arousal-testing paradigms to show that the fruit fly, Drosophila melanogaster, transitions between deeper and lighter sleep within extended bouts of inactivity, with deeper sleep intensities after15 and30 min of inactivity. As in mammals, the timing and intensity of these dynamic sleep processes in flies is homeostatically regulated and modulated by behavioral experience. Two molecules linked to synaptic plasticity regulate the intensity of the first deep sleep stage. Optogenetic upregulation of cyclic adenosine monophosphate during the day increases sleep intensity at night, whereas loss of function of a molecule involved in synaptic pruning, the fragile-X mental retardation protein, increases sleep intensity during the day. Our results show that sleep is not homogenous in insects, and suggest that waking behavior and the associated synaptic plasticity mechanisms determine the timing and intensity of deep sleep stages in Drosophila

    Activity of prostaglandin E, F, A and B on sphincter, dilator and ciliary muscle preparations of the cat eye

    Full text link
    Both sphincter and dilator muscle preparations of the cat iris contract to prostaglandins; F2[alpha] and E2 are the most potent and A1 and B1 the least. Ciliary muscle strips relax to PG's provided that the strips are precontracted. E1, E2 and often F2[alpha] are more potent relaxants than the remaining PG's. The effects of PG's are not altered by [alpha] or [beta] blockade nor by atropine; however, propranolol blocks the PG induced relaxation of the ciliary muscle. The effects of PG's on the sphincter are antagonized by catecholamines; but the latter act synergistically in contracting the dilator and in relaxing the ciliary muscle. Indomethacin markedly potentiates the effects of PG's on all three muscle preparations.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/22132/1/0000561.pd

    Elasticity of tissues involved in accommodation

    Full text link
    Uniaxial loading of human lens, zonules, ciliary muscle, and choroid shows a nonlinear relationship between stress and deformation of the specimen, and hysteresis on unloading. Spring constants, at 10% elongation, have been calculated for all specimens and for several combinations. Except for zonules they are significantly correlated with age. They will provide a basis for a model of accommodation. The mean force required for 10% elongation of the lens, at mean age 43, is about 22 x greater than for the zonules; and the mean elongation of the zonules is nearly 7 x that of the lens at a load of 0.01 N (~ 1 g). Ranges of forces and pressures in the accommodated and nonaccommodated eye are estimated.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/29667/1/0000756.pd

    Centre-specific bacterial pathogen typing affects infection-control decision making

    Get PDF
    Whole-genome sequencing is becoming the de facto standard for bacterial outbreak surveillance and infection prevention. This is accompanied by a variety of bioinformatic tools and needs bioinformatics expertise for implementation. However, little is known about the concordance of reported outbreaks when using different bioinformatic workflows. In this multi-centre proficiency testing among 13 major Dutch healthcare-affiliated centres, bacterial whole-genome outbreak analysis was assessed. Centres who participated obtained two randomized bacterial datasets of Illumina sequences, a Klebsiella pneumoniae and a Vancomycin-resistant Enterococcus faecium, and were asked to apply their bioinformatic workflows. Centres reported back on antimicrobial resistance, multi-locus sequence typing (MLST), and outbreak clusters. The reported clusters were analysed using a method to compare landscapes of phylogenetic trees and calculating Kendallā€“Colijn distances. Furthermore, fasta files were analysed by state-of-the-art single nucleotide polymorphism (SNP) analysis to mitigate the differences introduced by each centre and determine standardized SNP cut-offs. Thirteen centres participated in this study. The reported outbreak clusters revealed discrepancies between centres, even when almost identical bioinformatic workflows were used. Due to stringent filtering, some centres failed to detect extended-spectrum beta-lactamase genes and MLST loci. Applying a standardized method to determine outbreak clusters on the reported de novo assemblies, did not result in uniformity of outbreak-cluster composition among centres

    Using item response theory to explore the psychometric properties of extended matching questions examination in undergraduate medical education

    Get PDF
    BACKGROUND: As assessment has been shown to direct learning, it is critical that the examinations developed to test clinical competence in medical undergraduates are valid and reliable. The use of extended matching questions (EMQ) has been advocated to overcome some of the criticisms of using multiple-choice questions to test factual and applied knowledge. METHODS: We analysed the results from the Extended Matching Questions Examination taken by 4th year undergraduate medical students in the academic year 2001 to 2002. Rasch analysis was used to examine whether the set of questions used in the examination mapped on to a unidimensional scale, the degree of difficulty of questions within and between the various medical and surgical specialties and the pattern of responses within individual questions to assess the impact of the distractor options. RESULTS: Analysis of a subset of items and of the full examination demonstrated internal construct validity and the absence of bias on the majority of questions. Three main patterns of response selection were identified. CONCLUSION: Modern psychometric methods based upon the work of Rasch provide a useful approach to the calibration and analysis of EMQ undergraduate medical assessments. The approach allows for a formal test of the unidimensionality of the questions and thus the validity of the summed score. Given the metric calibration which follows fit to the model, it also allows for the establishment of items banks to facilitate continuity and equity in exam standards

    Advice of the Scientific Advisory Committee on Seal Rehabilitation in the Netherlands

    Get PDF
    Two species of seal breed in the Netherlands, the grey seal (Halichoerus grypus) and the harbour seal (Phoca vitulina). The populations of both species have increased markedly over the past 40 years. Harbour seals have recovered from a minimum number of around 500 in 1980 to some 9,000 seals in 2016 (Figure 1). Grey seals were effectively absent from the Netherlands until 1980, but have made a remarkable recovery; the numbers counted during the annual moult increased to around 5,100 in 2016. The number of pups born each year for both species is equivalent to around 20% of the number of seals counted during the moult
    • ā€¦
    corecore