1,184 research outputs found

    Interaction between the BDNF gene Val/66/Met polymorphism and morning cortisol levels as a predictor of depression in adult women.

    Get PDF
    BACKGROUND: Common genetic variants, such as the brain-derived neurotrophic factor (BDNF) Val/66/Met polymorphism (rs6265), are known to interact with environmental factors such as early adversity to increase the risk of subsequent major depression. Much less is known about how they interact with individual differences in cortisol, although these also represent a risk for major depression. AIMS: To determine whether this BDNF variant moderated the risk represented by higher levels of morning salivary cortisol in adult women. METHOD: We recruited 279 premenopausal women who were at high risk of major depressive disorder because of either negative self-evaluation, unsupportive core relationship or chronic subclinical symptoms of depression or anxiety. Morning salivary cortisol was measured daily for up to 10 days at entry. Participants were followed up for about 12 months by telephone calls at 3-4 monthly intervals. Major depression and severe life events were assessed through interviews at baseline and follow-up; DNA was obtained from the saliva. RESULTS: There were 53 onsets (19%) of depressive episodes during follow-up. There was a significant U-shaped relationship between adjusted morning cortisol levels at baseline and the probability of depression onset during follow-up. In total, 51% experienced at least one severe life event/difficulty, and this strongly predicted subsequent onsets of depressive episodes. The BDNF Val/66/Met genotype was not directly associated with onsets of depression or with cortisol levels, but there was significant interaction between Val/66/Met and cortisol: the association between baseline cortisol and depression was limited to those with the Val/66/Val variant. There was no interaction between life events and either this BDNF polymorphism or cortisol levels. CONCLUSIONS: Morning salivary cortisol interacts with the BDNF Val/66/Met polymorphism in predicting new depressive episodes. This paper adds to the evidence that single gene polymorphisms interact with endogenous factors to predict depression.This is the published version. It has been published by the Royal College of Psychiatrists in The British Journal of Psychiartry and can be found here: http://bjp.rcpsych.org/content/201/4/313.full.pdf+html. Information about the licence this work falls under can be found here: http://www.rcpsych.ac.uk/pdf/Wellcome%20Trust%20licence.pdf

    Tidal disruption of satellites and formation of narrow rings

    Full text link
    In this paper we investigate the formation of narrow planetary rings such as those found around Uranus and Saturn through the tidal disruption of a weak, gravitationally bound satellite that migrates within its Roche limit. Using NN-body simulations, we study the behaviour of rubble piles placed on circular orbits at different distances from a central planet. We consider both homogeneous satellites and differentiated bodies containing a denser core. We show that the Roche limit for a rubble pile is closer to the planet than for a fluid body of the same mean density. The Roche limit for a differentiated body is also closer to the planet than for a homogeneous satellite of the same mean density. Within its Roche limit, a homogeneous satellite totally disrupts and forms a narrow ring. The initial stages of the disruption are similar to the evolution of a viscous fluid ellipsoid, which can be computed semi-analytically. On the other hand, when a differentiated satellite is just within the Roche limit only the mantle is disrupted. This process is similar to Roche-lobe overflow in interacting binary stars and produces two narrow rings on either side of a remnant satellite. We argue that the Uranian rings, and possibly their shepherd satellites, could have been formed through the tidal disruption of a number of protomoons that were formed inside the corotation radius of Uranus and migrated slowly inwards as a result of tidal interaction with the planet.Comment: Accepted for publication in MNRAS. Some figures have been compressed to fit into astro-ph size guidelines. Please contact authors if full resolution images are require

    The WFC3 Galactic Bulge Treasury Program: A First Look at Resolved Stellar Population Tools

    Full text link
    [Abridged] When WFC3 is installed on HST, the community will have powerful new tools for investigating resolved stellar populations. The WFC3 Galactic Bulge Treasury program will obtain deep imaging on 4 low-extinction fields. These non-proprietary data will enable a variety of science investigations not possible with previous data sets. To aid in planning for the use of these data and for future proposals, we provide an introduction to the program, its photometric system, and the associated calibration effort. The observing strategy is based upon a new 5-band photometric system spanning the UV, optical, and near-infrared. With these broad bands, one can construct reddening-free indices of Teff and [Fe/H]. Besides the 4 bulge fields, the program will target 6 fields in well-studied star clusters, spanning a wide range of [Fe/H]. The cluster data serve to calibrate the indices, provide population templates, and correct the transformation of isochrones into the WFC3 photometric system. The bulge data will shed light on the bulge formation history, and will also serve as population templates for other studies. One of the fields includes 12 candidate hosts of extrasolar planets. CMDs are the most popular tool for analyzing resolved stellar populations. However, due to degeneracies among Teff, [Fe/H], and reddening in traditional CMDs, it can be difficult to draw robust conclusions from the data. The 5-band system used for the bulge Treasury observations will provide indices that are roughly orthogonal in Teff and [Fe/H], and we argue that model fitting in an index-index diagram will make better use of the information than fitting separate CMDs. We provide simulations to show the expected data quality and the potential for differentiating between different star-formation histories.Comment: Accepted for publication in The Astronomical Journal. 9 pages, 8 figures, latex, AJ forma

    Conceptualizing the Business Corporation: Insights from History

    Get PDF
    © 2020 Cambridge University Press. This paper has been accepted for publication and will appear in a revised form, subsequent to peer-review and/or editorial input by Cambridge University Press. This manuscript is made available under the terms of the Creative Commons Non-Commercial No-Derivatives License (CC-BY-NC-ND). For further information please see: https://creativecommons.org/licenses/by-nc-nd/4.0/The purpose of this symposium is to shed light on the genealogy of the idea of a business corporation, an economic institution which has long been regarded with a mixture of awe and apprehension. Each of the four original contributions addresses the history of some of its key features. In the process, each contributor reveals some of the insights that history has to teach us regarding the central concepts that inform contemporary debates about the nature of the corporation, the contours of the corporation’s purpose, the sources of corporate power, the functions of corporate law, the duties of directors, the status of shareholders, and the legitimacy of corporate rights.Peer reviewe

    Decade time-scale modulation of low mass X-ray binaries

    Full text link
    Regular observations by the All Sky Monitor aboard the Rossi X-ray Timing Explorer satellite have yielded well-sampled light-curves with a time baseline of over ten years. We find that up to eight of the sixteen brightest persistent low mass X-ray binaries show significant, possible sinusoidal, variations with periods of order ten years. We speculate on its possible origin and prevalence in the population of low mass X-ray binaries and we find the presence of a third object in the system, or long-period variability intrinsic to the donor star, as being attractive origins for the X-ray flux modulation we detect. For some of the objects in which we do not detect a signal, there is substantial short-term variation which may hide modest modulation on long time-scales. Decade time-scale modulations may thus be even more common.Comment: 8 pages, 4 figures, 2 tables. Accepted by MNRA

    Is socioeconomic status associated with biological aging as measured by telomere length?

    Get PDF
    It has been hypothesized that one way in which lower socioeconomic status (SES) affects health is by increasing the rate of biological aging. A widely used marker of biological aging is telomere length. Telomeres are structures at the ends of chromosomes that erode with increasing cell proliferation and genetic damage. We aimed to identify, through systematic review and meta-analysis, whether lower SES (greater deprivation) is associated with shorter telomeres. Thirty-one articles, including 29 study populations, were identified. We conducted 3 meta-analyses to compare the telomere lengths of persons of high and low SES with regard to contemporaneous SES (12 study populations from 10 individual articles), education (15 study populations from 14 articles), and childhood SES (2 study populations from 2 articles). For education, there was a significant difference in telomere length between persons of high and low SES in a random-effects model (standardized mean difference (SMD) = 0.060, 95% confidence interval (CI): 0.002, 0.118; P = 0.042), although a range of sensitivity analyses weakened this association. There was no evidence for an association between telomere length and contemporaneous SES (SMD = 0.104, 95% CI: −0.027, 0.236; P = 0.119) or childhood SES (SMD = −0.037, 95% CI: −0.143, 0.069; P = 0.491). These results suggest weak evidence for an association between SES (as measured by education) and biological aging (as measured by telomere length), although there was a lack of consistent findings across the SES measures investigated here

    Comparison of outcomes following arthroscopic capsular release for idiopathic, diabetic and secondary adhesive capsulitis of the shoulder: a systematic review

    Get PDF
    Introduction: Arthroscopic capsular release for adhesive capsulitis of the shoulder is a treatment option. The present study aimed to investigate the clinical outcomes following arthroscopic capsular release among idiopathic, diabetic and secondary adhesive capsulitis. Hypothesis: Different aetiological groups yield variable outcomes following arthroscopic capsular release. Materials and Methods: A literature search was performed using MEDLINE, EMBASE, CINAHL and the Cochrane Database in April 2017. Comparative studies that reported range of motion or functional outcomes following arthroscopic capsular release in patients with adhesive capsulitis were included. A systematic review of the studies was conducted following the PRISMA guidelines. Results: Six studies met the eligibility criteria. The overall population included 463 patients; 203 idiopathic, 61 diabetic and 199 secondary cases. Of four studies comparing idiopathic and diabetic patients, three reported significantly worse range of movement and function in the diabetic group at various follow up points. No significant difference in function and motion was reported between the idiopathic and secondary groups. Recurrent pain was highest in diabetic patients (26%) compared to idiopathic groups (0%) and the secondary group had a higher rate of revision surgery when compared to the idiopathic group (8.1% vs. 2.4%) Discussion: Arthroscopic capsular release has a high success rate regardless of the underlying aetiology. However, diabetic patients are reported to have more residual pain, reduced motion and inferior function compared to idiopathic cases. The rate of revision capsular release is higher among patients with post-surgical adhesive capsulitis when compared to idiopathic cases. Level of evidence: Level IV, systematic review

    Re-sprains during the first 3 months after initial ankle sprain are related to incomplete recovery: an observational study

    Get PDF
    QuestionWhat are prognostic factors for incomplete recovery, instability, re-sprains and pain intensity 12 months after patients consult primary care practitioners for acute ankle sprains?DesignObservational study.ParticipantsOne hundred and two patients who consulted their general practitioner or an emergency department for an acute ankle sprain were included in the study.Outcome measuresPossible prognostic factors were assessed at baseline and at 3 months follow-up. Outcome measures assessed at 12 months follow-up were self-reported recovery, instability, re-sprains and pain intensity.ResultsAt 3 months follow-up, 65% of the participants reported instability and 24% reported one or more re-sprains. At 12 months follow-up, 55% still reported instability and more than 50% regarded themselves not completely recovered. None of the factors measured at baseline could predict the outcome at 12 months follow-up. Additionally, prognostic factors from the physical examination of the non-recovered participants at 3 months could not be identified. However, among the non-recovered participants at 3 months follow-up, re-sprains and self-reported pain at rest at 3 months were related to incomplete recovery at 12 months.ConclusionA physical examination at 3 months follow-up for the non-recovered ankle sprain patient seems to have no additional value for predicting outcome at 12 months. However, for the non-recovered patients at 3 months follow-up, self-reported pain at rest and re-sprains during the first 3 months of follow-up seem to have a prognostic value for recovery at 12 months

    Comparison of two arthroscopic pump systems based on image quality

    Get PDF
    The effectiveness of arthroscopic pump systems has been investigated with either subjective measures or measures that were unrelated to the image quality. The goal of this study is to determine the performance of an automated pump in comparison to a gravity pump based on objective assessment of the quality of the arthroscopic view. Ten arthroscopic operations performed with a gravity pump and ten performed with an automated pump (FMS Duo system) were matched on duration of the surgery and shaver usage, type of operation, and surgical experience. Quality of the view was defined by means of the presence or absence of previously described definitions of disturbances (bleeding, turbidity, air bubbles, and loose fibrous tissue). The percentage of disturbances for all operations was assessed with a time-disturbance analysis of the recorded operations. The Mann–Whitney U test shows a significant difference in favor of the automated pump for the presence of turbidity only (Exact Sig. [2*(1-tailed Sig.)] = 0.015). Otherwise, no differences were determined (Exact Sig. [2*(1-tailed Sig.)] > 0.436). A new objective method is successfully applied to assess efficiency of pump systems based on the quality of the arthroscopic view. Important disturbances (bleeding, air bubbles, and loose fibrous tissue) are not reduced by an automated pump used in combination with a tourniquet. The most frequent disturbance turbidity is reduced by around 50%. It is questionable if this result justifies the use of an automated pump for straightforward arthroscopic knee surgeries using a tourniquet
    corecore