260 research outputs found

    The structural properties and star formation history of Leo T from deep LBT photometry

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    We present deep, wide-field g and r photometry of the transition type dwarf galaxy Leo T, obtained with the blue arm of the Large Binocular Telescope. The data confirm the presence of both very young (5 Gyr) stars. We study the structural properties of the old and young stellar populations by preferentially selecting either population based on their color and magnitude. The young population is significantly more concentrated than the old population, with half-light radii of 104+-8 and 148+-16 pc respectively, and their centers are slightly offset. Approximately 10% of the total stellar mass is estimated to be represented by the young stellar population. Comparison of the color-magnitude diagram (CMD) with theoretical isochrones as well as numerical CMD-fitting suggest that star formation began over 10 Gyr ago and continued in recent times until at least a few hundred Myr ago. The CMD-fitting results are indicative of two distinct star formation bursts, with a quiescent period around 3 Gyr ago, albeit at low significance. The results are consistent with no metallicity evolution and [Fe/H] ~ -1.5 over the entire age of the system. Finally, the data show little if any sign of tidal distortion of Leo T.Comment: 8 pages, 9 figures, some small textual changes, accepted for publication in the Astrophysical Journa

    Effects of clockwise and counterclockwise job shift work rotation on sleep and work-life balance on hospital nurses

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    Rotational shift work is associated with sleep disturbances, increased risk of cardiovascular and psychological disorders, and may negatively impact work\u2013life balance. The direction of shift rotation (Clockwise, CW or counterclockwise, CCW) and its role in these disorders are poorly understood. The aim of the study was to investigate the effect of the shift schedule direction on sleep quantity and quality, alertness and work performance, and on work\u2013life balance on hospital nurses. One-hundred female nurses, working a continuous rapid shift schedule in hospitals in the north of Italy, participated in this cross-sectional study. Fifty worked on CW rotation schedule (Morning: 6 a.m.\u20132 p.m., Afternoon: 2 p.m.\u201310 p.m., Night: 10 p.m.\u20136 a.m., 2 rest days) and fifty on CCW rotation (Afternoon, Morning, Morning, Night, 3 rest days). Data were collected by ad hoc questionnaire and daily diary. During the shift cycle CW nurses slept longer (7.40 \ub1 2.24 h) than CCW (6.09 \ub1 1.73; p < 0.001). CW nurses reported less frequently than CCW awakening during sleep (40% vs. 80%; p < 0.001), attention disturbance during work (20% vs. 64%; p < 0.001), and interference with social and family life (60% vs. 96% and 20% vs. 70%, respectively; p < 0.001). CCW rotating shift schedule seems to be characterized by higher sleep disturbances and a worse work\u2013life balance

    Syncope in a Working-Age Population: Recurrence Risk and Related Risk Factors

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    Syncope in a worker undertaking risky tasks may result in fatalities for the individual or for third parties. We aimed at assessing the rate of syncope recurrence and the risk factors underlying the likelihood of syncope relapse in a working-age population. A prospective cohort of all patients aged 18\u207b65 years consecutively admitted to the Emergency Department for syncope was enrolled. Risk of syncope relapse was assessed at a six-month, 1-year, and 5-year follow-up. Predictors of syncope recurrence have been evaluated at six months and 1 year from the syncope index by a multivariable logistic regression analysis. 348 patients were enrolled. Risk of syncope relapse was 9.2% at 6 months, 11.8% at 1 year, and 23.4% at 5 years. At 6-month follow-up, predictor of syncope recurrence was 653 prior lifetime syncope episodes. At 1-year, 653 prior lifetime syncope episodes, diabetes mellitus, and anaemia were risk factors for syncope relapse. There was an exceeding risk of recurrence in the first 6 months and a reduced risk of 3.5% per year after the first year. Anaemia, diabetes mellitus, and prior lifetime syncope burden are of importance when giving advice about the resumption of "high risk" jobs following a syncope episode

    Implantable loop recorder versus conventional diagnostic workup for unexplained recurrent syncope

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    Background The most recent syncope guideline recommends that implantable loop recorders (ILRs) are implanted in the early phase of evaluation of people with recurrent syncope of uncertain origin in the absence of high-risk criteria, and in high-risk patients after a negative evaluation. Observational and case-control studies have shown that loop recorders lead to earlier diagnosis and reduce the rate of unexplained syncopes, justifying their use in clinical practice. However, only randomised clinical trials with an emphasis on a primary outcome of specific ILR-guided diagnosis and therapy, rather than simply electrocardiogram (ECG) diagnosis, might change clinical practice. Objectives To assess the incidence of mortality, quality of life, adverse events and costs of ILRs versus conventional diagnostic workup in people with unexplained syncope. Search methods We searched the Cochrane Central Register of Controlled Trials (CENTRAL, Issue 3, 2015), MEDLINE, EMBASE, ClinicalTrials.gov and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) Search Portal in April 2015. No language restriction was applied. Selection criteria We included all randomised controlled trials of adult participants (i.e. >= 18 years old) with a diagnosis of unexplained syncope comparing ILR with standard diagnostic workup. Data collection and analysis Two independent review authors screened titles and abstracts of all potential studies we identified as a result of the literature search, extracted study characteristics and outcome data from included studies and assessed risk of bias for each study using the criteria outlined in the Cochrane Handbook for Systematic Reviews of Interventions. We contacted authors of trials for missing data. We analysed dichotomous data (all-cause mortality and aetiologic diagnosis) as risk ratios (RR) with 95% confidence intervals (CI). We used the Chi(2) test to assess statistical heterogeneity (with P < 0.1) and the I-2 statistic to measure heterogeneity among the trials. We created a 'Summary of findings' table using the five GRADE considerations (study limitations, consistency of effect, imprecision, indirectness and publication bias) to assess the quality of a body of evidence as it relates to the studies which contribute data to the meta-analyses for the prespecified outcomes. Main results We included four trials involving a total of 579 participants. With the limitation that only two studies reported data on mortality and none of them had considered death as a primary endpoint, the meta-analysis showed no evidence of a difference in the risk of long-term mortality between participants who received ILR and those who were managed conventionally at follow-up (RR 0.97, 95% CI 0.41 to 2.30; participants = 255; studies = 2; very low quality evidence) with no evidence of heterogeneity. No data on short term mortality were available. Two studies reported data on adverse events after ILR implant. Due to the lack of data on adverse events in one of the studies' arms, a formal meta-analysis was not performed for this outcome. Data from two trials seemed to show no difference in quality of life, although this finding was not supported by a formal analysis due to the differences in both the scores used and the way the data were reported. Data from two studies seemed to show a trend towards a reduction in syncope relapses after diagnosis in participants implanted with ILR. Cost analyses from two studies showed higher overall mean costs in the ILR group, if the costs incurred by the ILR implant were counted. The mean cost per diagnosis and the mean cost per arrhythmic diagnosis were lower for participants randomised to ILR implant. Participants who underwent ILR implantation experienced higher rates of diagnosis (RR (in favour of ILR) 0.61, 95% CI 0.54 to 0.68; participants = 579; studies = 4; moderate quality evidence), as compared to participants in the standard assessment group, with no evidence of heterogeneity. Authors' conclusions Our systematic review shows that there is no evidence that an ILR-based diagnostic strategy reduces long-term mortality as compared to a standard diagnostic assessment (very low quality evidence). No data were available for short-term all-cause mortality. Moderate quality evidence shows that an ILR-based diagnostic strategy increases the rate of aetiologic diagnosis as compared to a standard diagnostic pathway. No conclusive data were available on the other end-points analysed. Further trials evaluating the effect of ILRs in the diagnostic strategy of people with recurrent unexplained syncope are warranted. Future research should focus on the assessment of the ability of ILRs to change clinically relevant outcomes, such as quality of life, syncope relapse and costs

    Chemohormonal Therapy in Metastatic Hormone-Sensitive Prostate Cancer: Long-Term Survival Analysis of the Randomized Phase III E3805 CHAARTED Trial

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    Purpose Docetaxel added to androgen-deprivation therapy (ADT) significantly increases the longevity of some patients with metastatic hormone-sensitive prostate cancer. Herein, we present the outcomes of the CHAARTED (Chemohormonal Therapy Versus Androgen Ablation Randomized Trial for Extensive Disease in Prostate Cancer) trial with more mature follow-up and focus on tumor volume. Patients and Methods In this phase III study, 790 patients with metastatic hormone-sensitive prostate cancer were equally randomly assigned to receive either ADT in combination with docetaxel 75 mg/mm2 for up to six cycles or ADT alone. The primary end point of the study was overall survival (OS). Additional analyses of the prospectively defined low- and high-volume disease subgroups were performed. High-volume disease was defined as presence of visceral metastases and/or ≥ four bone metastases with at least one outside of the vertebral column and pelvis. Results At a median follow-up of 53.7 months, the median OS was 57.6 months for the chemohormonal therapy arm versus 47.2months for ADT alone (hazard ratio [HR], 0.72; 95% CI, 0.59 to 0.89; P = .0018). For patients with high-volume disease (n = 513), the median OS was 51.2 months with chemohormonal therapy versus 34.4 months with ADT alone (HR, 0.63; 95% CI, 0.50 to 0.79; P \u3c .001). For those with low-volume disease (n = 277), no OS benefit was observed (HR, 1.04; 95% CI, 0.70 to 1.55; P = .86). Conclusion The clinical benefit from chemohormonal therapy in prolonging OS was confirmed for patients with high-volume disease; however, for patients with low-volume disease, no OS benefit was discerned

    Abell 611. I. Weak lensing analysis with LBC

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    Aims: The Large Binocular Cameras (LBC) are two twin wide field cameras (FOV∼23′×25′) mounted at the prime foci of the 8.4 m Large Binocular Telescope (LBT). We performed a weak lensing analysis of the z=0.288 cluster Abell 611 on g-band data obtained by the blue-optimized LBC in order to estimate the cluster mass. Methods: Owing to the complexity of the PSF of LBC, we decided to use two different approaches, KSB and shapelets, to measure the shape of background galaxies and to derive the shear signal produced by the cluster. Then we estimated the cluster mass with both aperture densitometry and parametric model fits. Results: The combination of the large aperture of the telescope and the wide field of view allowed us to map a region well beyond the expected virial radius of the cluster and to get a high surface density for background galaxies (23 galaxies/arcmin2). This made it possible to estimate an accurate mass for Abell 611. We find that the mass within 1.5 Mpc is (8±3)×10^14 M from the aperture mass technique and (5±1)×10^14 M using the model fitting by an NFW mass density profile for both shapelet and KSB methods. This analysis demonstrates that LBC is a powerful instrument for weak gravitational lensing studies

    S1P lyase regulates DNA damage responses through a novel sphingolipid feedback mechanism

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    The injurious consequences of ionizing radiation (IR) to normal human cells and the acquired radioresistance of cancer cells represent limitations to cancer radiotherapy. IR induces DNA damage response pathways that orchestrate cell cycle arrest, DNA repair or apoptosis such that irradiated cells are either repaired or eliminated. Concomitantly and independent of DNA damage, IR activates acid sphingomyelinase (ASMase), which generates ceramide, thereby promoting radiation-induced apoptosis. However, ceramide can also be metabolized to sphingosine-1-phosphate (S1P), which acts paradoxically as a radioprotectant. Thus, sphingolipid metabolism represents a radiosensitivity pivot point, a notion supported by genetic evidence in IR-resistant cancer cells. S1P lyase (SPL) catalyzes the irreversible degradation of S1P in the final step of sphingolipid metabolism. We show that SPL modulates the kinetics of DNA repair, speed of recovery from G2 cell cycle arrest and the extent of apoptosis after IR. SPL acts through a novel feedback mechanism that amplifies stress-induced ceramide accumulation, and downregulation/inhibition of either SPL or ASMase prevents premature cell cycle progression and mitotic death. Further, oral administration of an SPL inhibitor to mice prolonged their survival after exposure to a lethal dose of total body IR. Our findings reveal SPL to be a regulator of ASMase, the G2 checkpoint and DNA repair and a novel target for radioprotection
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