931 research outputs found

    Improvement of heart rate recovery after exercise training in older people.

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    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

    Predicted Turbine Heat Transfer for a Range of Test Conditions

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    Comparisons are shown between predictions and experimental data for blade and endwall heat transfer. The comparisons of computational domain parisons are given for both vane and rotor geometries over an extensive range of Reynolds and Mach numbers. Comparisons are made with experimental data from a variety of sources. A number of turbulence models are available for predicting blade surface heat transfer, as well as aerodynamic performance. The results of an investigation to determine the turbulence model which gives the best agreement with experimental data over a wide range of test conditions are presented

    Hybrid Superconducting Neutron Detectors

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    A new neutron detection concept is presented that is based on superconductive niobium (Nb) strips coated by a boron (B) layer. The working principle of the detector relies on the nuclear reaction 10B+n \rightarrow α\alpha+ 7Li , with α\alpha and Li ions generating a hot spot on the current-biased Nb strip which in turn induces a superconducting-normal state transition. The latter is recognized as a voltage signal which is the evidence of the incident neutron. The above described detection principle has been experimentally assessed and verified by irradiating the samples with a pulsed neutron beam at the ISIS spallation neutron source (UK). It is found that the boron coated superconducting strips, kept at a temperature T = 8 K and current-biased below the critical current Ic, are driven into the normal state upon thermal neutron irradiation. As a result of the transition, voltage pulses in excess of 40 mV are measured while the bias current can be properly modulated to bring the strip back to the superconducting state, thus resetting the detector. Measurements on the counting rate of the device are presented and the future perspectives leading to neutron detectors with unprecedented spatial resolutions and efficiency are highlighted.Comment: 8 pages 6 figure

    Prehistory at high altitude. New surveys in the central-southern Apennines

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    The ‘Molise Survey Project’ aims, through systematic survey, to document evidence for the prehistoric occupation and exploitation of the Apennine Mountains. Here, we present some of the first results of the archaeological surveys, with a focus on the evidence from the Middle Palaeolithic to the Bronze Age

    A comparison between standard and crossfeed monopulse radars in presence of rough sea scattering and ship movements

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    Monopulse radars are widely used in tracking systems, due to their relative simplicity and theoretical precision, but the presence of multipath impairs the tracking capabilities of these radars, especially when multipath signals are strong, as in a naval environment. A special monopulse setup, the crossfeed, has been proposed in the past to provide an automatic cancellation from smooth sea multipath. In this contribution, the performances of such a system are analyzed in presence of rough sea scattering and compared with those of a standard monopulse setup. Particular attention is devoted to performance degradations due to possible phase errors in the passive network implementing the comparator and due to ship rolling and pitching. This latter requires a full 3D monopulse simulator for its correct evaluation

    Paper Session I-C - Meteorological Support to Assure Safe Access to Space

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    On March 26, 1987 an Atlas Centaur rocket (AC-67) carrying a Navy communications satellite was given a green light for launch by Cape Canaveral Range Weather. There were rain-showers in the area. By the time liftoff occurred, one had moved over the launch complex. AC-67 ascended into a heavy shower where the plume of ionized exhaust gasses assisted in triggering a lightning strike...a deadly conduit to an electrically-charged atmosphere. The boosterÕs guidance system was fried and the rocket veered off course. To protect the public, the rocket was destroyed by the range safety officer (RSO). The accident cost taxpayers $250 million. A cloud quite literally formed over Air Force weather support to the space program. The good news is in the subsequent 10 years, the Department of Defense, in concert with universities and national laboratories, learned a great deal about how to prevent this kind of incident from happening again. As a result, the record since AC-67 has been flawless

    Effect of different cryoprotectants on the structural preservation of follicles in frozen zebu bovine (Bos indicus) ovarian tissue

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    Cryopreservation of ovarian tissue is a new and promising technique for germ-line storage. The objective of this study was to evaluate the effect of four cryoprotectants (at two concentrations each) on the preservation of zebu bovine preantral follicles after ovarian cryostorage. Strips of ovarian cortex were cryopreserved using glycerol (GLY; 10 or 20%), ethylene glycol (EG), propanediol (PROH) or dimethylsulphoxide (DMSO; 1.5 or 3 M). In addition, a toxicity test was performed for each cryoprotectant by exposing the ovarian tissue to them without freezing. Tissues were analyzed by histology and transmission electron microscopy. Ovarian tissue frozen in either concentration of DMSO or PROH or in 10% GLY retained a higher percentage of morphologically normal follicles (73–88%) than tissue frozen in 20% GLY or in either concentration of EG (16–52%). In the toxicity test, exposure of tissues to DMSO, PROH or GLY resulted in higher percentages of normal follicles (80–97%) than exposure to EG (49%). Electron microscopy revealed damage to the ultrastructure of follicles frozen in 10% GLY, while follicles cryopreserved in DMSO and PROH at either concentration exhibited normal ultrastructure. In conclusion, DMSO and PROH were the most effective cryoprotectants for zebu ovarian tissue, preserving the structural integrity of somatic and reproductive cells within the ovary

    Prunus persica var. platycarpa (Tabacchiera Peach): bioactive compounds and antioxidant activity of pulp, peel and seed ethanolic extracts

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    A comparative analysis of ethanol extracts from peel, pulp and seed of Prunus persica var. platycarpa (Tabacchiera peach) was done. The total phenols, flavonoids and carotenoids content as well as the antioxidant properties were evaluated. Peach pulp extract was characterized by the highest total phytonutrients content and exhibited the highest antioxidant activity in all in vitro assays. Interestingly, pulp extract showed IC50 values of 2.7 and 2.2 g/mL at 30 and 60 minutes of incubation, respectively using -carotene bleaching test. A remarkable result was also obtained by using Fe-chelating assay (IC50 of 2.9 g/mL vs 1.3 g/mL for positive control BHT). Pulp extract was subjected to liquid chromatography-electrospray-tandem mass spectrometry (HPLC-ESI-MS/MS). Six main compounds, namely gallic acid, protocatechuic acid, protocatechualdehyde, chlorogenic acid, p-coumaric acid, and ferulic acid, were identified. Overall, the results suggest that Prunus persica var. platycarpa displays a good antioxidant activity and its consumption could be promote
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