160 research outputs found

    Photometric Variability and Rotation in Magnetic White Dwarfs

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    We present a search for long term (months—years) photometric variability in a sample of ten isolated magnetic white dwarfs using observations taken with the Liverpool Robotic Telescope between March 2005 and January 2007. These stars had previously been found to be photometrically stable on short (hours—one week) timescales [1]. We construct differential light curves for each target and then use CLEAN and Lomb‐Scargle periodograms to determine any periodicity that may be present. Photometric variability is detected in two of the targets during the observed timescale—G 240–72 and G 227–28. We find no variability in the remaining eight targets above the 1% level. Finally, we search for any correlations between the spin periods and intrinsic physical properties of magnetic white dwarfs, such as the magnetic field strength, temperature, mass and age

    NLTT5306: The shortest Period Detached White Dwarf + Brown Dwarf Binary

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    We have spectroscopically confirmed a brown dwarf mass companion to the hydrogen atmosphere white dwarf NLTT5306. The white dwarf's atmospheric parameters were measured using Sloan Digital Sky Survey and X-Shooter spectroscopy as T_eff=7756+/-35K and log(g)=7.68+/-0.08, giving a mass for the primary of M_WD=0.44+/-0.04 M_sun, at a distance of 71+/-4 pc with a cooling age of 710+/-50 Myr. The existence of the brown dwarf secondary was confirmed through the near-infrared arm of the X-Shooter data and a spectral type of dL4-dL7 was estimated using standard spectral indices. Combined radial velocity measurements from the Sloan Digital Sky Survey, X-Shooter and the Hobby-Eberly Telescope's High Resolution Spectrograph of the white dwarf gives a minimum mass of 56+/-3 M_jup for the secondary, confirming the substellar nature. The period of the binary was measured as 101.88+/-0.02 mins using both the radial velocity data and i'-band variability detected with the INT. This variability indicates 'day' side heating of the brown dwarf companion. We also observe H{\alpha} emission in our higher resolution data in phase with the white dwarf radial velocity, indicating this system is in a low level of accretion, most likely via a stellar wind. This system represents the shortest period white dwarf + brown dwarf binary and the secondary has survived a stage of common envelope evolution, much like its longer period counterpart, WD0137-349. Both systems likely represent bona-fide progenitors of cataclysmic variables with a low mass white dwarf and a brown dwarf donor.Comment: 9 pages, 11 figures, accepted for publication in MNRA

    Center for Interdisciplinary Remotely-Piloted Aircraft Studies (CIRPAS)

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    A remotely piloted aircraft research facility is described that will provide new capabilities for atmospheric and oceanographic measurements. The aircraft can fly up to 24 h over remote ocean regions, at low or high altitude, and in various other challenging mission scenarios. The aircraft will fly research missions at speeds of 40 m s^(−1) and provide high spatial resolution measurements. Data will be transmitted in real time to a ground station for analysis and decision-making purposes. The facility will expand the opportunities for universities to participate in field measurement programs

    Cardiovascular disease-related miRNAs expression: potential role as biomarkers and effects of training exercise

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    Cardiovascular diseases (CVDs) are one of the most important causes of mortality worldwide, therefore the need of effective preventive strategies is imperative. Aging is associated with significant changes in both cardiovascular structure and function that lower the threshold for clinical signs and symptoms, making older people more susceptible to CVDs morbidity and mortality. microRNAs (miRNAs) modulate gene expression at post-transcriptional level and increasing evidence has shown that miRNAs are involved in cardiovascular physiology and in the pathogenesis of CVDs. Physical activity is recommended by the medical community and the cardiovascular benefits of exercise are multifactorial and include important systemic effects on skeletal muscle, the peripheral vasculature, metabolism, and neuroendocrine systems, as well as beneficial modifications within the myocardium itself. In this review we describe the role of miRNAs and their dysregulation in several types of CVDs. We provide an overview of miRNAs in CVDs and of the effects of physical activity on miRNA regulation involved in both cardiovascular pathologies and age-related cardiovascular changes and diseases. Circulating miRNAs in response to acute and chronic sport exercise appear to be modulated following training exercise, and may furthermore serve as potential biomarkers for CVDs and different age-related CVDs

    OROS-methylphenidate to reduce ADHD symptoms in male prisoners aged 16-25 years: a RCT

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    Background It is estimated that 20–30% of prisoners meet diagnostic criteria for attention deficit hyperactivity disorder (ADHD). Methylphenidate reduces ADHD symptoms, but its effect among prisoners remains uncertain. Objectives The primary objective was to estimate the efficacy of osmotic release oral system (OROS) methylphenidate in reducing ADHD symptoms in male prisoners aged 16–25 years who met diagnostic criteria for ADHD. Secondary objectives investigated change for associated clinical and behavioural problems and the role of ADHD symptoms in mediating change in behaviour. Design A Phase IV, 8-week, parallel-arm, double-blind, randomised, placebo-controlled trial of OROS-methylphenidate, compared with placebo, in young male adult prisoners with ADHD. Participants were randomised in a 1 : 1 ratio of OROS-methylphenidate to placebo, stratified by prison. Setting Participants were recruited from Her Majesty’s Prison and Young Offender Institution Isis (London, England) and Her Majesty’s Young Offender Institution Polmont (Falkirk, Scotland). Participants The participants were 200 male prisoners with ADHD aged 16–25 years who met the diagnostic criteria for ADHD. Exclusion criteria included moderate or severe learning disability; serious risk of violence to researchers; current major depression, psychosis, mania or hypomania, or a past history of bipolar disorder or schizophrenia; and drug-seeking behaviour that was of sufficient severity to affect the titration protocol. Intervention The intervention was overencapsulated OROS-methylphenidate (18 mg) or placebo capsules. Trial medication was titrated weekly for 5 weeks against symptom reduction and adverse effects to a final dose of one to four capsules per day, followed by a stable dose for 3 weeks. Main outcome measures The primary outcome was ADHD symptoms at 8 weeks using the investigator-rated Conners’ Adult ADHD Rating Scale-Observer. There were 13 secondary outcomes, including measures of emotional dysregulation, general psychopathology, reports of behaviour by prison staff and engagement with educational activities. Results For the primary outcome, the estimated improvement between the OROS-methylphenidate and placebo arms was 0.57 points on the Conners’ Adult ADHD Rating Scale-Observer (95% confidence interval –2.41 to 3.56) at 8 weeks, with a standardised effect size of 0.06. The difference was not statistically significant and was smaller than the difference the trial was powered to detect. Responder rate, defined as a 20% reduction in the Conners’ Adult ADHD Rating Scale-Observer score, was 48.3% for the OROS-methylphenidate arm and 47.9% for the placebo arm. None of the 13 secondary outcomes that could be formally compared between the trial arms showed a significant effect and no mediators of change in behaviour were identified

    The Effects of Playing with Thin Dolls on Body Image and Food Intake in Young Girls

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    This study experimentally tested the effects of playing with thin dolls on body image and food intake in 6- to 10-year-old Dutch girls (N = 117). Girls were randomly assigned to play with a thin doll, an average-sized doll, or Legos in a no doll control condition. After 10 min, they participated in a taste-test and completed questionnaires about body image. No differences were found between conditions for any of the body image variables. However, girls who played with the average-sized doll ate significantly more food than girls in other exposure conditions. Although no support was found for the assumption that playing with thin dolls influences body image, the dolls directly affected actual food intake in these young girls

    Thriving under Stress: Selective Translation of HIV-1 Structural Protein mRNA during Vpr-Mediated Impairment of eIF4E Translation Activity

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    Translation is a regulated process and is pivotal to proper cell growth and homeostasis. All retroviruses rely on the host translational machinery for viral protein synthesis and thus may be susceptible to its perturbation in response to stress, co-infection, and/or cell cycle arrest. HIV-1 infection arrests the cell cycle in the G2/M phase, potentially disrupting the regulation of host cell translation. In this study, we present evidence that HIV-1 infection downregulates translation in lymphocytes, attributable to the cell cycle arrest induced by the HIV-1 accessory protein Vpr. The molecular basis of the translation suppression is reduced accumulation of the active form of the translation initiation factor 4E (eIF4E). However, synthesis of viral structural proteins is sustained despite the general suppression of protein production. HIV-1 mRNA translation is sustained due to the distinct composition of the HIV-1 ribonucleoprotein complexes. RNA-coimmunoprecipitation assays determined that the HIV-1 unspliced and singly spliced transcripts are predominantly associated with nuclear cap binding protein 80 (CBP80) in contrast to completely-spliced viral and cellular mRNAs that are associated with eIF4E. The active translation of the nuclear cap binding complex (CBC)-bound viral mRNAs is demonstrated by ribosomal RNA profile analyses. Thus, our findings have uncovered that the maintenance of CBC association is a novel mechanism used by HIV-1 to bypass downregulation of eIF4E activity and sustain viral protein synthesis. We speculate that a subset of CBP80-bound cellular mRNAs contribute to recovery from significant cellular stress, including human retrovirus infection

    A systematic review, evidence synthesis and meta-analysis of quantitative and qualitative studies evaluating the clinical effectiveness, the cost-effectiveness, safety and acceptability of interventions to prevent postnatal depression

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    Background: Postnatal depression (PND) is a major depressive disorder in the year following childbirth, which impacts on women, their infants and their families. A range of interventions has been developed to prevent PND. Objectives: To (1) evaluate the clinical effectiveness, cost-effectiveness, acceptability and safety of antenatal and postnatal interventions for pregnant and postnatal women to prevent PND; (2) apply rigorous methods of systematic reviewing of quantitative and qualitative studies, evidence synthesis and decision-analytic modelling to evaluate the preventive impact on women, their infants and their families; and (3) estimate cost-effectiveness. Data sources: We searched MEDLINE, EMBASE, Science Citation Index and other databases (from inception to July 2013) in December 2012, and we were updated by electronic alerts until July 2013. Review methods: Two reviewers independently screened titles and abstracts with consensus agreement. We undertook quality assessment. All universal, selective and indicated preventive interventions for pregnant women and women in the first 6 postnatal weeks were included. All outcomes were included, focusing on the Edinburgh Postnatal Depression Scale (EPDS), diagnostic instruments and infant outcomes. The quantitative evidence was synthesised using network meta-analyses (NMAs). A mathematical model was constructed to explore the cost-effectiveness of interventions contained within the NMA for EPDS values. Results: From 3072 records identified, 122 papers (86 trials) were included in the quantitative review. From 2152 records, 56 papers (44 studies) were included in the qualitative review. The results were inconclusive. The most beneficial interventions appeared to be midwifery redesigned postnatal care [as shown by the mean 12-month EPDS score difference of –1.43 (95% credible interval –4.00 to 1.36)], person-centred approach (PCA)-based and cognitive–behavioural therapy (CBT)-based intervention (universal), interpersonal psychotherapy (IPT)-based intervention and education on preparing for parenting (selective), promoting parent–infant interaction, peer support, IPT-based intervention and PCA-based and CBT-based intervention (indicated). Women valued seeing the same health worker, the involvement of partners and access to several visits from a midwife or health visitor trained in person-centred or cognitive–behavioural approaches. The most cost-effective interventions were estimated to be midwifery redesigned postnatal care (universal), PCA-based intervention (indicated) and IPT-based intervention in the sensitivity analysis (indicated), although there was considerable uncertainty. Expected value of partial perfect information (EVPPI) for efficacy data was in excess of £150M for each population. Given the EVPPI values, future trials assessing the relative efficacies of promising interventions appears to represent value for money. Limitations: In the NMAs, some trials were omitted because they could not be connected to the main network of evidence or did not provide EPDS scores. This may have introduced reporting or selection bias. No adjustment was made for the lack of quality of some trials. Although we appraised a very large number of studies, much of the evidence was inconclusive. Conclusions: Interventions warrant replication within randomised controlled trials (RCTs). Several interventions appear to be cost-effective relative to usual care, but this is subject to considerable uncertainty. Future work recommendations: Several interventions appear to be cost-effective relative to usual care, but this is subject to considerable uncertainty. Future research conducting RCTs to establish which interventions are most clinically effective and cost-effective should be considered

    Cohort Profile: Post-Hospitalisation COVID-19 (PHOSP-COVID) study

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