1,247 research outputs found
H.e.s.s. and MAGIC observations of a sudden cessation of a very-high-energy γ -ray flare in PKS 1510-089 in May 2016
Investigation of the correlation patterns and the Compton dominance variability of Mrk 421 in 2017
Improvement of heart rate recovery after exercise training in older people.
Twenty-four subjects aged 70 and older were retrospectively selected from our archives and screened for symptoms of cardiovascular disease. Baseline exercise test was negative for myocardial ischemia in all subjects. All subjects had completed an 8-week program, performed for
a variety of indications and consisting of an aerobic physical training program including 30 minutes of cycling three times per week at 65% to 75% of maximum heart rate achieved at peak exercise test performed at enrollment, an educational intervention, dietary advice, and psychological
support. All subjects underwent a cardiopulmonary exercise test (CPX) before and at the end of
exercise training. At the end of each CPX, peak oxygen uptake (VO2peak), the rate of increase of ventilation per unit of increase of carbon dioxide production (VE/VCO2slope), and HRR were recorded. Twenty-five healthy subjects younger than 60 with no evidence of exercise-induced myocardial ischemia and not enrolled in any exercise training program were also retrospectively
selected from our archives and used as a control group for analyzing HRR. These patients performed two exercise tests several weeks apart. Several studies have shown that changes in vagal tone can be used as an outcome tool that helps identify patients or subjects with or without cardiovascular disease at risk for a cardiovascular event, although the evidence of a prognostic value of HRR in older subjects without cardiovascular disease is rather poor. In this study, exercise training resulted in HRR improvement in healthy elderly subjects, suggesting that exercise training improves vagal/sympathetic balance in older subjects without cardiovascular disease as well. Whether the observed improvement in HRR may have long-term beneficial prognostic effects was not the aim of the study, although a beneficial effect might be postulated, in light of the Framingham dat
Sensitivity of the Cherenkov Telescope Array for probing cosmology and fundamental physics with gamma-ray propagation
Zebrafish, a novel model system to study uremic toxins: The case for the sulfur amino acid lanthionine
The non-proteinogenic amino acid lanthionine is a byproduct of hydrogen sulfide biosynthesis: the third endogenous vasodilator gas, after nitric oxide and carbon monoxide. While hydrogen sulfide is decreased in uremic patients on hemodialysis, lanthionine is increased and has been proposed as a new uremic toxin, since it is able to impair hydrogen sulfide production in hepatoma cells. To characterize lanthionine as a uremic toxin, we explored its effects during the early development of the zebrafish (Danio rerio), a widely used model to study the organ and tissue alterations induced by xenobiotics. Lanthionine was employed at concentrations reproducing those previously detected in uremia. Light-induced visual motor response was also studied by means of the DanioVision system. Treatment of zebrafish embryos with lanthionine determined acute phenotypical alterations, on heart organogenesis (disproportion in cardiac chambers), increased heart beating, and arrhythmia. Lanthionine also induced locomotor alterations in zebrafish embryos. Some of these effects could be counteracted by glutathione. Lanthionine exerted acute effects on transsulfuration enzymes and the expression of genes involved in inflammation and metabolic regulation, and modified microRNA expression in a way comparable with some alterations detected in uremia. Lanthionine meets the criteria for classification as a uremic toxin. Zebrafish can be successfully used to explore uremic toxin effects
Prospects for detecting Gamma-Ray Bursts with the Cherenkov Telescope Array
The Large Area Telescope (LAT) on the Fermi gamma-ray satellite telescope observes Gamma-Ray Bursts (GRBs) at energies above 100 MeV. Thanks to a new detection algorithm and a new event reconstruction, it is expected to publish a catalogue with more than 100 GRBs. This work aims at revising the prospects for GRB alerts with the Cherenkov Telescope Array (CTA) based on the new LAT results. We start by considering the simulation of the observations with the full CTA of two extremely bright events, the long GRB 130427A and the short GRB 090510; then we investigate how these GRBs would be observed by different subsamples of the array pointing to different directions, adopting the \u201ccoupled divergent\u201d mode
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