1,638 research outputs found

    The LEECH Exoplanet Imaging Survey: Limits on Planet Occurrence Rates Under Conservative Assumptions

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    We present the results of the largest LL^{\prime} (3.8 μ3.8~\mum) direct imaging survey for exoplanets to date, the Large Binocular Telescope Interferometer (LBTI) Exozodi Exoplanet Common Hunt (LEECH). We observed 98 stars with spectral types from B to M. Cool planets emit a larger share of their flux in LL^{\prime} compared to shorter wavelengths, affording LEECH an advantage in detecting low-mass, old, and cold-start giant planets. We emphasize proximity over youth in our target selection, probing physical separations smaller than other direct imaging surveys. For FGK stars, LEECH outperforms many previous studies, placing tighter constraints on the hot-start planet occurrence frequency interior to 20\sim20 au. For less luminous, cold-start planets, LEECH provides the best constraints on giant-planet frequency interior to 20\sim20 au around FGK stars. Direct imaging survey results depend sensitively on both the choice of evolutionary model (e.g., hot- or cold-start) and assumptions (explicit or implicit) about the shape of the underlying planet distribution, in particular its radial extent. Artificially low limits on the planet occurrence frequency can be derived when the shape of the planet distribution is assumed to extend to very large separations, well beyond typical protoplanetary dust-disk radii (50\lesssim50 au), and when hot-start models are used exclusively. We place a conservative upper limit on the planet occurrence frequency using cold-start models and planetary population distributions that do not extend beyond typical protoplanetary dust-disk radii. We find that 90%\lesssim90\% of FGK systems can host a 7 to 10 MJupM_{\mathrm{Jup}} planet from 5 to 50 au. This limit leaves open the possibility that planets in this range are common.Comment: 31 pages, 13 figures, accepted to A

    Locating and building knowledges outside of the academy : approaches to engaged teaching at the University of Sheffield

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    This article draws on three case studies, which illuminate a number of practical, ethical and intellectual issues that arise from engaged teaching activities within the curriculum. Projects from the disciplines of Architecture, English and Journalism Studies illustrate the possibilities offered by learning and teaching projects which emphasise public facing, co-produced knowledge as central components. It is argued that such approaches enable dynamic forms of learning to emerge, which work to expand the parameters of subject-specific knowledge while enabling the development of citizenship attributes and employability skills amongst students in ways that deepen, rather than dilute, intellectual rigour. The article locates these practical pedagogical reflections within theoretical frameworks offered by those working (largely in North America* on publicly engaged approaches to scholarship and seeks to draw connections with contemporary developments in learning and teaching in the UK. Keywords: civic university; engaged teaching; engaged scholarship; co-productio

    Genetic variants in RBFOX3 are associated with sleep latency

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    Time to fall asleep (sleep latency) is a major determinant of sleep quality. Chronic, long sleep latency is a major characteristic of sleep-onset insomnia and/or delayed sleep phase syndrome. In this study we aimed to discover common polymorphisms that contribute to the genetics of sleep latency. We performed a meta-analysis of genome-wide association studies (GWAS) including 2 572 737 single nucleotide polymorphisms (SNPs) established in seven European cohorts including 4242 individuals. We found a cluster of three highly correlated variants (rs9900428, rs9907432 and rs7211029) in the RNA-binding protein fox-1 homolog 3 gene (RBFOX3) associated with sleep latency (P-values=5.77 × 10-08, 6.59 × 10- 08 and 9.17 × 10- 08). These SNPs were replicated in up to 12 independent populations including 30 377 individuals (P-values=1.5 × 10- 02, 7.0 × 10- 03 and 2.5 × 10- 03; combined meta-analysis P-values=5.5 × 10-07, 5.4 × 10-07 and 1.0 × 10-07). A functional prediction of RBFOX3 based on co-expression with other genes shows that this gene is predominantly expressed in brain (P-value=1.4 × 10-316) and the central nervous system (P-value=7.5 × 10- 321). The predicted function of RBFOX3 based on co-expression analysis with other genes shows that this gene is significantly involved in the release cycle of neurotransmitte

    Presacral malakoplakia presenting as foot drop: a case report

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    Background: Malakoplakia is a rare condition characterized by inflammatory masses with specific histological characteristics. These soft tissue masses can mimic tumors and tend to develop in association with chronic or recurrent infections, typically of the urinary tract. A specific defect in innate immunity has been described. In the absence of randomized controlled trials, management is based on an understanding of the biology and on case reports. Case presentation: Here we describe a case of presacral malakoplakia in a British Indian woman in her late 30s, presenting with complex unilateral foot drop. Four years earlier, she had suffered a protracted episode of intrapelvic sepsis following a caesarean delivery. Resection of her presacral soft tissue mass was not possible. She received empiric antibiotics, a cholinergic agonist, and ascorbic acid. She responded well to medical management both when first treated and following a recurrence of symptoms after completing an initial 8 months of therapy. Whole exome sequencing of the patient and her parents was undertaken but no clear causal variant was identified. Conclusions: Malakoplakia is uncommon but the diagnosis should be considered where soft tissue masses develop at the site of chronic or recurrent infections. Obtaining tissue for histological examination is key to making the diagnosis. This case suggests that surgical resection is not always needed to achieve a good clinical and radiological outcome

    Cross-cutting principles for planetary health education

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    Since the 2015 launch of the Rockefeller Foundation Lancet Commission on planetary health,1 an enormous groundswell of interest in planetary health education has emerged across many disciplines, institutions, and geographical regions. Advancing these global efforts in planetary health education will equip the next generation of scholars to address crucial questions in this emerging field and support the development of a community of practice. To provide a foundation for the growing interest and efforts in this field, the Planetary Health Alliance has facilitated the first attempt to create a set of principles for planetary health education that intersect education at all levels, across all scales, and in all regions of the world—ie, a set of cross-cutting principles

    An international multi-cohort investigation of self-reported sleep and future depressive symptoms in older adults

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    Poor subjective sleep is associated with future depression in older adults, but there is limited consensus on which sleep features have the strongest associations. Moreover, composite scores incorporating multiple features may better represent sleep burden than individual sleep items. We analyzed older adults (age ≥ 60) without clinically relevant depressive symptoms from a multi-cohort United States sample (US; N = 4826) and the Netherlands’ Rotterdam Study (RS; N = 3663), with the goal of identifying individual and composite sleep features that are associated with future clinically relevant depressive symptoms 3–6 years later. Sleep-related daytime symptoms (Risk Ratio [95% CI] 2.10 [1.58, 2.80] in US; 2.10 [1.40, 3.14] in RS) and difficulty falling asleep (1.87 [1.49, 2.35] in US; RS = 1.90 [1.50, 2.43] in RS) were the strongest individual sleep features. Moreover, the combination of these features was most impactful (3.32 [2.33, 4.73] in US; 3.19 [2.64, 3.86] in RS), providing the largest effect size with the fewest number of items. Future studies should assess whether screening tools incorporating these features, paired with targeted sleep treatment, could reduce rates of incident depression in older adults. Examining mechanisms underlying these associations could improve the effectiveness of sleep-related treatments in older adults.</p

    The genetic etiology of periodic limb movement in sleep

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    Study Objectives Periodic limb movement in sleep is a common sleep phenotype characterized by repetitive leg movements that occur during or before sleep. We conducted a genome-wide association study (GWAS) of periodic limb movements in sleep (PLMS) using a joint analysis (i.e., discovery, replication, and joint meta-analysis) of four cohorts (MrOS, the Wisconsin Sleep Cohort Study, HypnoLaus, and MESA), comprised of 6843 total subjects. Methods The MrOS study and Wisconsin Sleep Cohort Study (N = 1745 cases) were used for discovery. Replication in the HypnoLaus and MESA cohorts (1002 cases) preceded joint meta-analysis. We also performed LD score regression, estimated heritability, and computed genetic correlations between potentially associated traits such as restless leg syndrome (RLS) and insomnia. The causality and direction of the relationships between PLMS and RLS was evaluated using Mendelian randomization. Results We found 2 independent loci were significantly associated with PLMS: rs113851554 (p = 3.51 x 10(-12), beta = 0.486), an SNP located in a putative regulatory element of intron eight of MEIS1 (2p14);and rs9369062 (p = 3.06 x 10(-22), beta = 0.2093), a SNP located in the intron region of BTBD9 (6p12);both of which were also lead signals in RLS GWAS. PLMS is genetically correlated with insomnia, risk of stroke, and RLS, but not with iron deficiency. Pleiotropy adjusted Mendelian randomization analysis identified a causal effect of RLS on PLMS. Conclusions Because PLMS is more common than RLS, PLMS may have multiple causes and additional studies are needed to further validate these findings
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