34 research outputs found

    A spectroscopic search for White Dwarf companions to 101 nearby M dwarfs

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    Recent studies of the stellar population in the solar neighborhood (<20 pc) suggest that there are undetected white dwarfs (WDs) in multiple systems with main sequence companions. Detecting these hidden stars and obtaining a more complete census of nearby WDs is important for our understanding of binary and galactic evolution, as well as the study of explosive phenomena. In an attempt to uncover these hidden WDs, we present intermediate resolution spectroscopy over the wavelength range 3000-25000 \AA\ of 101 nearby M dwarfs (dMs), observed with the Very Large Telescope X-Shooter spectrograph. For each star we search for a hot component superimposed on the dM spectrum. X-Shooter has excellent blue sensitivity and thus can reveal a faint hot WD despite the brightness of its red companion. Visual examination shows no clear evidence of a WD in any of the spectra. We place upper limits on the effective temperatures of WDs that may still be hiding by fitting dM templates to the spectra, and modeling WD spectra. On average our survey is sensitive to WDs hotter than about 5300 K. This suggests that the frequency of WD companions of T<5300 K with separation of order <50 AU among the local dM population is <3% at the 95% confidence level. The reduced spectra are made available on via WISeREP repository.Comment: 41 pages, 105 figures, 2 tables. Submitted to AAS journal

    Human PIF1 helicase supports DNA replication and cell growth under oncogenic-stress

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    Unwinding duplex DNA is a critical processing step during replication, repair and transcription. Pif1 are highly conserved non-processive 5′->3′ DNA helicases with well-established roles in maintenance of yeast genome stability. However, the function of the sole member of Pif1 family in humans remains unclear. Human PIF1 is essential for tumour cell viability, particularly during replication stress, but is dispensable in non-cancerous cells and Pif1 deficient mice. Here we report that suppression of PIF1 function slows replication fork rates and increases arrested forks during normal cycling conditions. Importantly, PIF1-dependent replication impediments impair S-phase progression and reduce proliferation rates of RAS oncogene-transformed fibroblasts, where replication fork slowing is exacerbated, but not parental, non-cancerous cells. Disrupted fork movement upon PIF1-depletion does not enhance double-stranded break formation or DNA damage responses but affects resumption of DNA synthesis after prolonged replication inhibitor exposure, accompanied by diminished new origin firing and mainly S-phase entry. Taken together, we characterised a functional role for human PIF1 in DNA replication that becomes important for cell growth under oncogenic stress. Given that oncogenes induce high levels of replication stress during the early stages of tumorigenesis, this function of PIF1 could become critical during cancer development

    The Changing Landscape for Stroke\ua0Prevention in AF: Findings From the GLORIA-AF Registry Phase 2

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    Background GLORIA-AF (Global Registry on Long-Term Oral Antithrombotic Treatment in Patients with Atrial Fibrillation) is a prospective, global registry program describing antithrombotic treatment patterns in patients with newly diagnosed nonvalvular atrial fibrillation at risk of stroke. Phase 2 began when dabigatran, the first non\u2013vitamin K antagonist oral anticoagulant (NOAC), became available. Objectives This study sought to describe phase 2 baseline data and compare these with the pre-NOAC era collected during phase&nbsp;1. Methods During phase 2, 15,641 consenting patients were enrolled (November 2011 to December 2014); 15,092 were eligible. This pre-specified cross-sectional analysis describes eligible patients\u2019 baseline characteristics. Atrial fibrillation&nbsp;disease characteristics, medical outcomes, and concomitant diseases and medications were collected. Data were analyzed using descriptive statistics. Results Of the total patients, 45.5% were female; median age was 71 (interquartile range: 64, 78) years. Patients were from Europe (47.1%), North America (22.5%), Asia (20.3%), Latin America (6.0%), and the Middle East/Africa (4.0%). Most had high stroke risk (CHA2DS2-VASc [Congestive heart failure, Hypertension, Age&nbsp; 6575 years, Diabetes mellitus, previous Stroke, Vascular disease, Age 65 to 74 years, Sex category] score&nbsp; 652; 86.1%); 13.9% had moderate risk (CHA2DS2-VASc&nbsp;= 1). Overall, 79.9% received oral anticoagulants, of whom 47.6% received NOAC and 32.3% vitamin K antagonists (VKA); 12.1% received antiplatelet agents; 7.8% received no antithrombotic treatment. For comparison, the proportion of phase 1 patients (of N&nbsp;= 1,063 all eligible) prescribed VKA was 32.8%, acetylsalicylic acid 41.7%, and no therapy 20.2%. In Europe in phase 2, treatment with NOAC was more common than VKA (52.3% and 37.8%, respectively); 6.0% of patients received antiplatelet treatment; and 3.8% received no antithrombotic treatment. In North America, 52.1%, 26.2%, and 14.0% of patients received NOAC, VKA, and antiplatelet drugs, respectively; 7.5% received no antithrombotic treatment. NOAC use was less common in Asia (27.7%), where 27.5% of patients received VKA, 25.0% antiplatelet drugs, and 19.8% no antithrombotic treatment. Conclusions The baseline data from GLORIA-AF phase 2 demonstrate that in newly diagnosed nonvalvular atrial fibrillation patients, NOAC have been highly adopted into practice, becoming more frequently prescribed than VKA in&nbsp;Europe and North America. Worldwide, however, a large proportion of patients remain undertreated, particularly in&nbsp;Asia&nbsp;and North America. (Global Registry on Long-Term Oral Antithrombotic Treatment in Patients With Atrial Fibrillation [GLORIA-AF]; NCT01468701

    “A lot of medical students, their biggest fear is failing at being seen to be a functional human”:disclosure and help-seeking decisions by medical students with health problems

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    BACKGROUND: Although medical students have a duty to seek advice for their health conditions, they tend to avoid disclosure and help-seeking behaviours, therefore potentially posing a risk to themselves and their patients. The literature regarding their decisions to seek help or disclose health conditions is limited. The study’s purpose was to explore the factors that determine disclosure and help-seeking decision processes by medical students who have health conditions with or without disability. METHODS: We recruited by purposive sampling and conducted in-depth semi-structured interviews with 11 male and female medical students from a UK medical school, who had physical or mental health disorders. Thematic analysis was used to identify themes. A mix of inductive and deductive techniques was used while using an organising framework proposed by Llewellyn-Thomas (1995). RESULTS: The impact of individuals’ features, such as personality traits on medical students’ disclosure and help-seeking decisions were identified. Different aspects of the condition, such as its type and severity were found to influence these decisions. Participants made an evaluation of the potential receiver of a disclosure, consisting of factors such as the receiver’s characteristics and attitudes. The culture of the medical environment, such as role models, had a major impact on their decisions. Finally, systemic factors, such as the lack of clarity of policies influenced students’ decisions. CONCLUSION: Medical students’ disclosure and help-seeking decision processes are influenced by risk-benefit evaluations and factors in interlinked spheres of their lives. They tend to avoid or postpone disclosure and seeking help, especially when the university is involved, due to a perceived risk to their future. Future research should examine the role of personality traits and the medical culture. Medical schools should encourage earlier help-seeking and disclosure behaviours by clarifying procedures and building trust via online and confidential platforms; interpersonal channels and normalisation processes within the medical education and the profession as a whole. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12909-021-03032-9

    Poor acute outcome in congestive heart failure is associated with increases in the plasma static oxidation–reduction potentials (sORP) in men but not in women

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    Objectives: In congestive heart failure (CHF), men are younger, more likely to have reduced ejection fraction (HF-rEF), and to be diabetic compared to women. Despite this, sex differences in oxidative stress have yet to be explored in CHF. Methods: Data from 67 males and 63 females hospitalized for CHF were collected. Static oxidation–reduction potential (sORP), a relative indicator of oxidative stress, and capacity ORP (icORP), a relative indicator of antioxidant capacity, were measured from plasma samples. We examined whether sex modified the relationship between ORP and hospital discharge disposition (poor outcome: death, hospice), along with other demographics, medications, and diagnostic parameters. Results: Males with poor outcomes had higher sORP and icORP values than females (P \u3c 0.05). For those with a good outcome, there were no differences between the sexes (P \u3e 0.05). Males were younger and more likely to have HF-rEF and diabetes. Controlling for these variables did not account for the sex differences in ORP measures. Regardless of sex, higher creatinine was related to higher sORP and icORP, while lower magnesium and potassium were related to higher sORP and icORP, respectively. Discussion: Increases in sORP during CHF are partially affected by sex and acute outcomes, but are also related to variables without sexual biases

    Panel discussion

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    Panel discussion

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    Multi-SimLex: A Large-Scale Evaluation of Multilingual and Cross-Lingual Lexical Semantic Similarity

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    We introduce Multi-SimLex, a large-scale lexical resource and evaluation benchmark covering data sets for 12 typologically diverse languages, including major languages (e.g., Mandarin Chinese, Spanish, Russian) as well as less-resourced ones (e.g., Welsh, Kiswahili). Each language data set is annotated for the lexical relation of semantic similarity and contains 1,888 semantically aligned concept pairs, providing a representative coverage of word classes (nouns, verbs, adjectives, adverbs), frequency ranks, similarity intervals, lexical fields, and concreteness levels. Additionally, owing to the alignment of concepts across languages, we provide a suite of 66 cross-lingual semantic similarity data sets. Due to its extensive size and language coverage, Multi-SimLex provides entirely novel opportunities for experimental evaluation and analysis. On its monolingual and cross-lingual benchmarks, we evaluate and analyze a wide array of recent state-of-the-art monolingual and cross-lingual representation models, including static and contextualized word embeddings (such as fastText, monolingual and multilingual BERT, XLM), externally informed lexical representations, as well as fully unsupervised and (weakly) supervised cross-lingual word embeddings. We also present a step-by-step data set creation protocol for creating consistent, Multi-Simlex -style resources for additional languages. We make these contributions - the public release of Multi-SimLex data sets, their creation protocol, strong baseline results, and in-depth analyses which can be be helpful in guiding future developments in multilingual lexical semantics and representation learning - available via a website which will encourage community effort in further expansion of Multi-SimLex to many more languages. Such a large-scale semantic resource could inspire significant further advances in NLP across languages
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