119 research outputs found
The GALEX View of "Boyajian's Star" (KIC 8462852)
The enigmatic star KIC 8462852, informally known as "Boyajian's Star", has
exhibited unexplained variability from both short timescale (days) dimming
events, and years-long fading in the Kepler mission. No single physical
mechanism has successfully explained these observations to date. Here we
investigate the ultraviolet variability of KIC 8462852 on a range of timescales
using data from the GALEX mission that occurred contemporaneously with the
Kepler mission. The wide wavelength baseline between the Kepler and GALEX data
provides a unique constraint on the nature of the variability. Using 1600
seconds of photon-counting data from four GALEX visits spread over 70 days in
2011, we find no coherent NUV variability in the system on 10-100 second or
months timescales. Comparing the integrated flux from these 2011 visits to the
2012 NUV flux published in the GALEX-CAUSE Kepler survey, we find a 3% decrease
in brightness for KIC 8462852. We find this level of variability is
significant, but not necessarily unusual for stars of similar spectral type in
the GALEX data. This decrease coincides with the secular optical fading
reported by Montet & Simon (2016). We find the multi-wavelength variability is
somewhat inconsistent with typical interstellar dust absorption, but instead
favors a R = 5.0 0.9 reddening law potentially from circumstellar
dust.Comment: 8 pages, 4 figures, ApJ Accepte
Genome-wide association studies and cross-population meta-analyses investigating short and long sleep duration
Sleep duration has been linked to a wide range of negative health outcomes and to reduced life expectancy. We present genome-wide association studies of short ( ≤ 5 h) and long ( ≥ 10 h) sleep duration in adults of European (N = 445,966), African (N = 27,785), East Asian (N = 3141), and admixed-American (N = 16,250) ancestry from UK Biobank and the Million Veteran Programme. In a cross-population meta-analysis, we identify 84 independent loci for short sleep and 1 for long sleep. We estimate SNP-based heritability for both sleep traits in each ancestry based on population derived linkage disequilibrium (LD) scores using cov-LDSC. We identify positive genetic correlation between short and long sleep traits (rg = 0.16 ± 0.04; p = 0.0002), as well as similar patterns of genetic correlation with other psychiatric and cardiometabolic phenotypes. Mendelian randomisation reveals a directional causal relationship between short sleep and depression, and a bidirectional causal relationship between long sleep and depression
Basal body stability and ciliogenesis requires the conserved component Poc1
Centrioles are the foundation for centrosome and cilia formation. The biogenesis of centrioles is initiated by an assembly mechanism that first synthesizes the ninefold symmetrical cartwheel and subsequently leads to a stable cylindrical microtubule scaffold that is capable of withstanding microtubule-based forces generated by centrosomes and cilia. We report that the conserved WD40 repeat domain–containing cartwheel protein Poc1 is required for the structural maintenance of centrioles in Tetrahymena thermophila. Furthermore, human Poc1B is required for primary ciliogenesis, and in zebrafish, DrPoc1B knockdown causes ciliary defects and morphological phenotypes consistent with human ciliopathies. T. thermophila Poc1 exhibits a protein incorporation profile commonly associated with structural centriole components in which the majority of Poc1 is stably incorporated during new centriole assembly. A second dynamic population assembles throughout the cell cycle. Our experiments identify novel roles for Poc1 in centriole stability and ciliogenesis
Search for Na in novae supported by a novel method for measuring femtosecond nuclear lifetimes
Classical novae are thermonuclear explosions in stellar binary systems, and
important sources of Al and Na. While gamma rays from the decay
of the former radioisotope have been observed throughout the Galaxy, Na
remains untraceable. The half-life of Na (2.6 yr) would allow the
observation of its 1.275 MeV gamma-ray line from a cosmic source. However, the
prediction of such an observation requires good knowledge of the nuclear
reactions involved in the production and destruction of this nucleus. The
Na()Mg reaction remains the only source of large
uncertainty about the amount of Na ejected. Its rate is dominated by a
single resonance on the short-lived state at 7785.0(7) keV in Mg. In the
present work, a combined analysis of particle-particle correlations and
velocity-difference profiles is proposed to measure femtosecond nuclear
lifetimes. The application of this novel method to the study of the Mg
states, combining magnetic and highly-segmented tracking gamma-ray
spectrometers, places strong limits on the amount of Na produced in
novae, explains its non-observation to date in gamma rays (flux < 2.5x
ph/(cms)), and constrains its detectability with future space-borne
observatories.Comment: 18 pages, 3 figures, 1 tabl
Alveolar Rhabdomyosarcoma with Regional Nodal Involvement: Results of a Combined Analysis from Two Cooperative Groups
BACKGROUND: Treatment of children and adolescents with alveolar rhabdomyosarcoma (ARMS) and regional nodal involvement (N1) have been approached differently by North American and European cooperative groups. In order to define the better therapeutic strategy, we analyzed two studies conducted between 2005 and 2016 by the European paediatric Soft tissue sarcoma Study Group (EpSSG) and Children’s Oncology Group (COG). METHODS: We retrospectively identified patients with ARMS-N1 enrolled in either EpSSG RMS2005 or in COG ARST0531. Chemotherapy in RMS2005 comprised IVADo (ifosfamide, vincristine, dactinomycin, doxorubicin), IVA and maintenance (vinorelbine, cyclophosphamide); in ARST0531 it consisted on either VAC (vincristine, dactinomycin, cyclophosphamide) or VAC alternating with VI (vincristine, irinotecan). Local treatment was similar in both protocols. RESULTS: The analysis of the clinical characteristics of 239 patients showed some differences between study groups: in RMS2005, advanced IRS Group and large tumors predominated. There were no differences in outcomes between the two groups: 5-year event-free survival (EFS), 49%(95%CI=39–59) and 44%(95%CI=30–58), and overall survival (OS), 51%(95%CI=41–61) and 53.6%(95%CI=40–68), in RMS2005 and ARST0531, respectively. In RMS2005, EFS of patients with FOXO1-positive tumors was significantly inferior to those FOXO1-negative (49.3% vs 73%, p=0.034). In contrast, in ARST0531, EFS of patients with FOXO1-positive tumors was 45% compared with 43.8% for those FOXO1-negative. CONCLUSIONS: The outcome of patients with ARMS N1 was similar in both protocols. However, patients with FOXO1 fusion-negative tumors enrolled in RMS2005 showed a significantly better outcome, suggesting that different strategies of chemotherapy may have an impact in the outcome of this subgroup of patients
Mild-to-Moderate Kidney Dysfunction and Cardiovascular Disease: Observational and Mendelian Randomization Analyses
BACKGROUND: End-stage renal disease is associated with a high risk of cardiovascular events. It is unknown, however, whether mild-to-moderate kidney dysfunction is causally related to coronary heart disease (CHD) and stroke. METHODS: Observational analyses were conducted using individual-level data from 4 population data sources (Emerging Risk Factors Collaboration, EPIC-CVD [European Prospective Investigation into Cancer and Nutrition-Cardiovascular Disease Study], Million Veteran Program, and UK Biobank), comprising 648 135 participants with no history of cardiovascular disease or diabetes at baseline, yielding 42 858 and 15 693 incident CHD and stroke events, respectively, during 6.8 million person-years of follow-up. Using a genetic risk score of 218 variants for estimated glomerular filtration rate (eGFR), we conducted Mendelian randomization analyses involving 413 718 participants (25 917 CHD and 8622 strokes) in EPIC-CVD, Million Veteran Program, and UK Biobank. RESULTS: There were U-shaped observational associations of creatinine-based eGFR with CHD and stroke, with higher risk in participants with eGFR values 105 mL·min-1·1.73 m-2, compared with those with eGFR between 60 and 105 mL·min-1·1.73 m-2. Mendelian randomization analyses for CHD showed an association among participants with eGFR 105 mL·min-1·1.73 m-2. Results were not materially different after adjustment for factors associated with the eGFR genetic risk score, such as lipoprotein(a), triglycerides, hemoglobin A1c, and blood pressure. Mendelian randomization results for stroke were nonsignificant but broadly similar to those for CHD. CONCLUSIONS: In people without manifest cardiovascular disease or diabetes, mild-to-moderate kidney dysfunction is causally related to risk of CHD, highlighting the potential value of preventive approaches that preserve and modulate kidney function
Target genes, variants, tissues and transcriptional pathways influencing human serum urate levels.
Elevated serum urate levels cause gout and correlate with cardiometabolic diseases via poorly understood mechanisms. We performed a trans-ancestry genome-wide association study of serum urate in 457,690 individuals, identifying 183 loci (147 previously unknown) that improve the prediction of gout in an independent cohort of 334,880 individuals. Serum urate showed significant genetic correlations with many cardiometabolic traits, with genetic causality analyses supporting a substantial role for pleiotropy. Enrichment analysis, fine-mapping of urate-associated loci and colocalization with gene expression in 47 tissues implicated the kidney and liver as the main target organs and prioritized potentially causal genes and variants, including the transcriptional master regulators in the liver and kidney, HNF1A and HNF4A. Experimental validation showed that HNF4A transactivated the promoter of ABCG2, encoding a major urate transporter, in kidney cells, and that HNF4A p.Thr139Ile is a functional variant. Transcriptional coregulation within and across organs may be a general mechanism underlying the observed pleiotropy between urate and cardiometabolic traits.The Genotype-Tissue Expression (GTEx) Project was supported by the Common Fund of the Office of the Director of the National Institutes of Health, and by NCI, NHGRI, NHLBI, NIDA, NIMH, and NINDS. Variant annotation was supported by software resources provided via the Caché Campus program of the InterSystems GmbH to Alexander Teumer
Politics ahead of patients: The battle between medical and chiropractic professional associations over the inclusion of chiropractic in the American Medicare System
Health care professions struggling for legitimacy, recognition, and market share can become disoriented to their priorities. Health care practitioners are expected to put the interests of patients first. Professional associations represent the interests of their members. So when a professional association is composed of health care practitioners, its interests may differ from those of patients, creating a conflict for members. In addition, sometimes practitioners’ perspectives may be altered by indoctrination in a belief system, or misinformation, so that a practitioner could be confused about the reality of patient needs. Politicians, in attempting to find an expedient compromise, can value a “win” in the legislative arena over the effects of that legislation. These forces all figure into the events that led to the acceptance of chiropractic into the American Medicare system. Two health care systems in a political fight lost sight of their main purpose: to provide care to patients without doing harm.
Dans leur recherche de légitimité, de reconnaissance et d’une juste part sur le marché de la santé, les professionnels de la santé peuvent perdre de vue leurs priorités. Ces praticiens doivent donner préséance aux intérêts des patients tandis que les associations professionnelles représentent ceux de leurs membres. Lorsqu’une association professionnelle regroupe des praticiens de la santé cependant, ses intérêts s’opposent parfois à ceux des patients, créant ainsi un conflit pour les membres. De plus, les praticiens peuvent être endoctrinés par un système de valeurs ou mal informés, au point de se tromper dans l’évaluation des besoins réels des patients. De leur côté, les politiciens peuvent préférer une « victoire » dans l’arène législative à une juste appréciation des impacts d’une loi. Ces forces ont toutes participé aux évènements qui ont mené à l’acceptation de la chiropraxie par le système américain Medicare. Dans cette bataille politique, deux systèmes de santé ont négligé leur principal objectif : soigner des patients sans leur nuire
The mutable nature of particle-core excitations with spin in the one-valence-proton nucleus ¹³³Sb
The γ-ray decay of excited states of the one-valence-proton nucleus ¹³³Sb has been studied using cold-neutron induced fission of ²³⁵U and ²⁴¹Pu targets, during the EXILL campaign at the ILL reactor in Grenoble. By using a highly efficient HPGe array, coincidences between γ-rays prompt with the fission event and those delayed up to several tens of microseconds were investigated, allowing to observe, for the first time, high-spin excited states above the 16.6 μs isomer. Lifetimes analysis, performed by fast-timing techniques with LaBr₃(Ce) scintillators, revealed a difference of almost two orders of magnitude in B(M1) strength for transitions between positive-parity medium-spin yrast states. The data are interpreted by a newly developed microscopic model which takes into account couplings between core excitations (both collective and non-collective) of the doubly magic nucleus ¹³²Sn and the valence proton, using the Skyrme effective interaction in a consistent way. The results point to a fast change in the nature of particle-core excitations with increasing spin
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