249 research outputs found

    Observation of Motion Dependent Nonlinear Dispersion with Narrow Linewidth Atoms in an Optical Cavity

    Full text link
    As an alternative to state-of-the-art laser frequency stabilisation using ultra-stable cavities, it has been proposed to exploit the non-linear effects from coupling of atoms with a narrow transition to an optical cavity. Here we have constructed such a system and observed non-linear phase shifts of a narrow optical line by strong coupling of a sample of strontium-88 atoms to an optical cavity. The sample temperature of a few mK provides a domain where the Doppler energy scale is several orders of magnitude larger than the narrow linewidth of the optical transition. This makes the system sensitive to velocity dependent multi-photon scattering events (Dopplerons) that affect the cavity field transmission and phase. By varying the number of atoms and the intra-cavity power we systematically study this non-linear phase signature which displays roughly the same features as for much lower temperature samples. This demonstration in a relatively simple system opens new possibilities for alternative routes to laser stabilization at the sub 100 mHz level and superradiant laser sources involving narrow line atoms. The understanding of relevant motional effects obtained here has direct implications for other atomic clocks when used in relation with ultranarrow clock transitions.Comment: 9 pages (including 4 pages of Supplemental Information), 6 figures. Updated to correspond to the published versio

    Population-wide analysis of differences in disease progression patterns in men and women

    Get PDF
    Sex-stratified medicine is an important and understudied field. Here the authors investigate in a systematic study of the Danish population differences in incidence, risk, and several aspects of diagnoses between sexes and find differences across all areas of disease

    The transcriptome of corona radiata cells from individual MII oocytes that after ICSI developed to embryos selected for transfer: PCOS women compared to healthy women

    Get PDF
    BACKGROUND: Corona radiata cells (CRCs) refer to the fraction of cumulus cells just adjacent to the oocyte. The CRCs are closely connected to the oocyte throughout maturation and their gene expression profiles might reflect oocyte quality. Polycystic ovary syndrome (PCOS) is a common cause of infertility. It is controversial whether PCOS associate with diminished oocyte quality. The purpose of this study was to compare individual human CRC samples between PCOS patients and controls. METHODS: All patients were stimulated by the long gonadotropin-releasing hormone (GnRH) agonist protocol. The CRC samples originated from individual oocytes developing into embryos selected for transfer. CRCs were isolated in a two-step denudation procedure, separating outer cumulus cells from the inner CRCs. Extracted RNA was amplified and transcriptome profiling was performed with Human Agilent® arrays. RESULTS: The transcriptomes of CRCs showed no individual genes with significant differential expression between PCOS and controls, but gene set enrichment analysis identified several cell cycle- and DNA replication pathways overexpressed in PCOS CRCs (FDR < 0.05). Five of the genes contributing to the up-regulated cell cycle pathways in the PCOS CRCs were selected for qRT-PCR validation in ten PCOS and ten control CRC samples. qRT-PCR confirmed significant up-regulation in PCOS CRCs of cell cycle progression genes HIST1H4C (FC = 2.7), UBE2C (FC = 2.6) and cell cycle related transcription factor E2F4 (FC = 2.5). CONCLUSION: The overexpression of cell cycle-related genes and cell cycle pathways in PCOS CRCs could indicate a disturbed or delayed final maturation and differentiation of the CRCs in response to the human chorionic gonadotropin (hCG) surge. However, this had no effect on the in vitro development of the corresponding embryos. Future studies are needed to clarify whether the up-regulated cell cycle pathways in PCOS CRCs have any clinical implications. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13048-014-0110-6) contains supplementary material, which is available to authorized users

    Convergent and discriminant validity of the Minimal Eating Observation Form - version II: a cross-sectional study

    Get PDF
    Background: The Minimal Eating Observation Form – Version II (MEOF-II) is a brief and easy to use screening tool for eating difficulties, that is psychometrically robust. The aim of this study was to explore convergent (measuring similar constructs) and discriminant (measuring somewhat different constructs) validity of the MEOF-II to other validated dysphagia specific, activity and participation related instruments. Methods: In this cross-sectional study, participants (n = 100, mean age 72, n = 42 women), diagnosed with either chronic pulmonary disease, Parkinson´s disease, Multiple Sclerosis, or stroke were recruited from rehabilitation centres. Patient-reported outcomes and clinical-rated assessments, capturing eating ability in general and swallowing in specific, included: The Dysphagia Handicap Index (DHI), the 4-question test (4QT), the Minimal Eating Observation Form – II, the Volume – Viscosity Swallow Test (V-VST), Flexible Endoscopic Evaluation of Swallowing (FEES) documented according to the Penetration-Aspiration Scale (PAS). Type of oral intake was documented using the Functional Oral Intake Scale (FOIS). Activities in daily living was assessed with Barthel index (BI). Spearman’s correlation coefficient was used to analyze associations. The MEOF-II total score was hypothesised to have moderate correlations (r ≥ 0.3) with the other assessments, besides with PAS and FOIS (weak correlations, r &lt; 0.3). Results: In total 78 participants had any type of eating difficulties (MEOF-II), 69 reported dysphagia (4QT), 62 had dysphagia according to V-VST, 29 showed evidence of penetration/aspiration (PAS), and 31 participants had decreased oral intake ability (FOIS). The MEOF-II total score had moderate correlations with DHI, BI, 4QT, V-VST volume, and weak correlations with V-VST dysphagia and viscosity, PAS, and FOIS. Comparing a prior hypothesised correlation strengths against empirical findings showed that 83% of the hypothesised correlations were correct. Conclusions: The MEOF-II is a holistic and objective screening tool that can indicate the need for further assessment and corresponds well with the persons’ subjective experiences. MEOF-II does not specifically assess the risk for penetration/aspiration.</p

    Construct validity of the Dissociative Experiences Scale (DES): I. The relationship between the DES and other self-report measures of DES

    Get PDF
    p. 185-188The present study attempted to expand the construct validity of the Dissociative Experiences Scale (DES) by comparing it to: (a) other self-report measures of dissociation (e.g., the Tellegen Absorption Scale [TAS] and the Perceptual Alteration Scale [PAS]); (b) the construct of "ambiguity intolerance" (assessed by the Yellen Ambiguity Intolerance Scale [YAIS]); and (c) the Jenkins Activity Schedule (JAS: which measures the degree of Type A behavior). Three hundred and eleven undergraduates participated in an experiment on "Hypnotizability and Personality, " and filled out the DES TAS, PAS, YAIS, and JAS. The DES total score (and three DES factor scores) correlated with the TAS and PAS in the range of .24 - .52 (all correlations were significant at the .001 level, two-tailed). Furthermore, the DES total score (and the three DES factor scores) correlated significantly with the YAIS overall score (r's ranged from .22 - .24, all p's < .001), but did not correlate significantly with the JAS (r's ranged from -.03 - .04, ns). The findings suggest that DES scores (i.e., total scores and each of the three DES factor scores) show good levels of convergent validity as they correlate significantly with other self-report measures of dissociation. However, the intercorrelations were not high enough to consider the different dissociation measures as interchangeable. Furthermore, subjects reporting high levels of dissociative experiences also reported higher levels of ambiguity intolerance. However, no significant association was observed between DES scores and the Type A behavior pattern

    ‘The invention of counting: the statistical measurement of literacy in nineteenth-century England’

    Get PDF
    This article examines the invention of counting literacy on a national basis in nineteenth-century Britain. Through an analysis of Registrar Generals' reports, it describes how the early statisticians wrestled with the implications of their new-found capacity to describe a nation's communications skills in a single table and how they were unable to escape their model of a society of isolated individuals divided into the literate and illiterate. The continuing influence of this approach is traced in the recent report from the Organisation for Economic Co-operation and Development's (OECD) Programme for the International Assessment of Adult Competencies (PIACC)
    corecore