969 resultados para Training load


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Résumé Il a été démontré que l'exercice physique modifiait le contrôle de la thermorégulation cutané, ce qui se manifeste par une augmentation de la perfusion de la microcirculation de la peau. Pour une même augmentation de température, ce phénomène est plus important chez les sportifs d'endurance que chez les sujets sédentaires. Dans cette étude, nous posons l'hypothèse qu'une composante de cette adaptation peut provenir d'une plus haute capacité des vaisseaux sanguins à répondre à un stimulus vasodilatateur. Pour la tester, nous avons recruté des hommes sains, non fumeurs, soit entraînés (surtout sport d'endurance) ou sédentaires que nous avons partagé en deux classes d'âges (18-35 ans [jeunes] et >50 ans[âgés]). Le flux sanguin cutané était mesuré par un laser-Doppler au niveau de la peau de l'avant-bras. Nous avons alors mesuré la vasodilatation obtenue par les stimuli suivant : Iontophorèse à l'acétylcholine (ACh, un vasodilatateur dépendant de l'endothélium), iontophorèse au nitroprussiate de sodium (SNP, un donneur d'oxyde nitrique) et par libération d'une interruption momentanée du flux artériel huméral (hyperémie réactive). Chez les sujets entraînés, l'effet de l'hyperémie réactive et de l'ACh n'ont pas montré de différence. Par contre, l'augmentation de la perfusion, suivant la iontophorèse de SNP, exprimé en unité de perfusion (PU), était plus importante chez les sujets entraînés que chez les sujets sédentaires (jeunes: 398±54 vs 350±87, p<0.05; âgés: 339±72 vs 307±66, p<0.05). Pour conclure, l'entraînement d'endurance augmente l'effet vasodilatateur de l'oxyde nitrique de la microcirculation cutanée humaine, au moins au niveau de la peau de l'avant-bras. Ces observations ont un intérêt physiologique considérable au vu des résultats d'études récentes qui montrent que le NO sert d'intermédiaire dans la vasodilatation cutanée produite par un stress thermique. Donc, l'augmentation de la bioactivité du NO dans la microcirculation cutanée pourrait être un des mécanismes par lequel l'entraînement physique modifierait le contrôle de la thermorégulation du flux sanguin cutané. Abstract Endurance training modifies the thermoregulatory control of skin blood flow, as manifested by a greater augmentation of skin perfusion for the same increase in core temperature in athletes, in comparison with se-dentary subjects. In this study, we tested the hypothesis that a component of this adaptation might reside in a higher ability of cutaneous blood vessels to respond to vasodilatory stimuli. We recruited healthy nonsmoking males, either endurance trained or sedentary, in two different age ranges (18-35 y and >50 y). Skin blood flow was measured in the forearm skin, using a laser Doppler imager, allowing to record the vasodilatory responses to the following stimuli: iontophoresis of acetylcholine (an endothelium-dependent vasodilator), iontophoresis of sodium nitroprusside (a nitric oxide donor), and release of a temporary interruption of arterial inflow (reactive hyperemia). There was no effect of training on reactive hyperemia or the response to acetylcholine. In contrast, the increase in perfusion following the iontophoresis of sodium nitroprusside, ex-pressed in perfusion units, was larger in trained than in sedentary subjects (younger: 398±54 vs 350±87, p<0.05; older 339±72 vs 307±66, p<0.05). In conclusion, endurance training enhances the vasodilatory effects of nitric oxide in the human dermal microcirculation, at least in forearm skin. These observations have considerable physiologic interest in view of recent data indicating that nitric oxide mediates in part the cutaneous vasodilation induced by heat stress in humans. Therefore, the augmentation of nitric oxide bioactivity in the dermal microcirculation might be one mechanism whereby endurance training modifies the thermoregulatory control of skin blood flow.

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PURPOSE: Repeated-sprint training in hypoxia (RSH) was recently shown to improve repeated-sprint ability (RSA) in cycling. This phenomenon is likely to reflect fiber type-dependent, compensatory vasodilation, and therefore, our hypothesis was that RSH is even more beneficial for activities involving upper body muscles, such as double poling during cross-country skiing. METHODS: In a double-blinded fashion, 17 competitive cross-country skiers performed six sessions of repeated sprints (each consisting of four sets of five 10-s sprints, with 20-s intervals of recovery) either in normoxia (RSN, 300 m; FiO2, 20.9%; n = 8) or normobaric hypoxia (RSH, 3000 m; FiO2, 13.8 %; n = 9). Before (pre) and after (post) training, performance was evaluated with an RSA test (10-s all-out sprints-20-s recovery, until peak power output declined by 30%) and a simulated team sprint (team sprint, 3 × 3-min all-out with 3-min rest) on a double-poling ergometer. Triceps brachii oxygenation was measured by near-infrared spectroscopy. RESULTS: From pretraining to posttraining, peak power output in the RSA was increased (P < 0.01) to the same extent (29% ± 13% vs 26% ± 18%, nonsignificant) in RSH and in RSN whereas the number of sprints performed was enhanced in RSH (10.9 ± 5.2 vs 17.1 ± 6.8, P < 0.01) but not in RSN (11.6 ± 5.3 vs 11.7 ± 4.3, nonsignificant). In addition, the amplitude in total hemoglobin variations during sprints throughout RSA rose more in RSH (P < 0.01). Similarly, the average power output during all team sprints improved by 11% ± 9% in RSH and 15% ± 7% in RSN. CONCLUSIONS: Our findings reveal greater improvement in the performance of repeated double-poling sprints, together with larger variations in the perfusion of upper body muscles in RSH compared with those in RSN.

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BACKGROUND: Communication in cancer care has become a major topic of interest. Since there is evidence that ineffective communication affects both patients and oncology clinicians (physicians and nurses), so-called communication skills trainings (CSTs) have been developed over the last decade. While these trainings have been demonstrated to be effective, there is an important heterogeneity with regard to implementation and with regard to evidence of different aspects of CST. METHODS: In order to review and discuss the scientific literature on CST in oncology and to formulate recommendations, the Swiss Cancer League has organised a consensus meeting with European opinion leaders and experts in the field of CST, as well as oncology clinicians, representatives of oncology societies and patient organisations. On the basis of a systematic review and a meta-analysis, recommendations have been developed and agreed upon. RESULTS: Recommendations address (i) the setting, objectives and participants of CST, (ii) its content and pedagogic tools, (iii) organisational aspects, (iv) outcome and (v) future directions and research. CONCLUSION: This consensus meeting, on the basis of European expert opinions and a systematic review and meta-analysis, defines key elements for the current provision and future development and evaluation of CST in oncology.

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Desde una perspectiva narrativa, este artículo explora cómo la práctica y la formación en interpretación de conferenciasse han percibido en la disciplina, en la profesión y en diferentescolectivos de traductores e interpretes comprometid@s como ECOSy Babels. Sostiene que estas distintas maneras de percibir la interpretación no son meramente opuestas sino que su potencial confluencia es clave para hacer posible una interpretación de conferencias más comprometida políticamente y más socio-crítica en un mundo de desigualdades cada vez más acentuadas y de mercantilización creciente de todos los aspectos de la vida. El artículo lleva a cabo un estudio de caso sobre la formación ad hoc de intérpretes en el Foro Social, en particular el Foro Social Europeo de Londres, y analiza cómo el trabajo colectivo entre instituciones educativas y sociedad civil tanto local como global ha dado luz a prácticas transformadoras hacia una metodología de formación mássocio-critica y con mayor consciencia ética.

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Hispanics make up a growing percentage of the craft workers entering the construction industry, and this has created several challenges for American construction companies. This study addresses the situation by investigating training needs for Hispanic construction craft workers and developing a training program for them within the industry. In order to evaluate current craft workers’ conditions within the construction industry, Iowa State University researchers conducted a survey, with 98 Hispanic craft workers as respondents from 10 construction companies, to determine current working conditions. The results confirm that the language barrier is an obstacle for both the Hispanic workers and the English-speaking employees involved in construction projects. As a part of this research, two training courses were designed to help both American construction companies and their Hispanic labor force to overcome the barriers that keep them from succeeding safely and productively. A training course titled English as a Second Language Survival Course was developed to facilitate basic communication between Hispanic workers and their American supervisors using construction-focused terminology. This course was delivered once as a trial run for a two-hour duration and twice for a full-length duration of eight hours. Important feedback was obtained from participants as part of the evaluations of the course. “How much of the course contents will be useful in your working environment” was asked; 40% of workers said “all of it” and 60% said “most of it.” Another question was “Was it worth taking the time to attend the course?” to which 94% answered “definitely” and 6% answered “yes.” A second training course titled Stepping Up to Supervisor Course for Hispanic Construction Workers was also developed to provide an effective tool to help companies promote those Hispanic craft workers whose willingness and skills meet the requirements to advance to a supervisory position in an American construction company. This course will be offered in the spring of 2004.

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BACKGROUND: Allostatic load reflects cumulative exposure to stressors throughout lifetime and has been associated with several adverse health outcomes. It is hypothesized that people with low socioeconomic status (SES) are exposed to higher chronic stress and have therefore greater levels of allostatic load. OBJECTIVE: To assess the association of receiving social transfers and low education with allostatic load. METHODS: We included 3589 participants (1812 women) aged over 35years and under retirement age from the population-based CoLaus study (Lausanne, Switzerland, 2003-2006). We computed an allostatic load index aggregating cardiovascular, metabolic, dyslipidemic and inflammatory markers. A novel index additionally including markers of oxidative stress was also examined. RESULTS: Men with low vs. high SES were more likely to have higher levels of allostatic load (odds ratio (OR)=1.93/2.34 for social transfers/education, 95%CI from 1.45 to 4.17). The same patterns were observed among women. Associations persisted after controlling for health behaviors and marital status. CONCLUSIONS: Low education and receiving social transfers independently and cumulatively predict high allostatic load and dysregulation of several homeostatic systems in a Swiss population-based study. Participants with low SES are at higher risk of oxidative stress, which may justify its inclusion as a separate component of allostatic load.

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Quantifying the impacts of inbreeding and genetic drift on fitness traits in fragmented populations is becoming a major goal in conservation biology. Such impacts occur at different levels and involve different sets of loci. Genetic drift randomly fixes slightly deleterious alleles leading to different fixation load among populations. By contrast, inbreeding depression arises from highly deleterious alleles in segregation within a population and creates variation among individuals. A popular approach is to measure correlations between molecular variation and phenotypic performances. This approach has been mainly used at the individual level to detect inbreeding depression within populations and sometimes at the population level but without consideration about the genetic processes measured. For the first time, we used in this study a molecular approach considering both the interpopulation and intrapopulation level to discriminate the relative importance of inbreeding depression vs. fixation load in isolated and non-fragmented populations of European tree frog (Hyla arborea), complemented with interpopulational crosses. We demonstrated that the positive correlations observed between genetic heterozygosity and larval performances on merged data were mainly caused by co-variations in genetic diversity and fixation load among populations rather than by inbreeding depression and segregating deleterious alleles within populations. Such a method is highly relevant in a conservation perspective because, depending on how populations lose fitness (inbreeding vs. fixation load), specific management actions may be designed to improve the persistence of populations.

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Annual Report

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In this final project the high availability options for PostgreSQL database management system were explored and evaluated. The primary objective of the project was to find a reliable replication system and implement it to a production environment. The secondary objective was to explore different load balancing methods and compare their performance. The potential replication methods were thoroughly examined, and the most promising was implemented to a database system gathering weather information in Lithuania. The different load balancing methods were tested performance wise with different load scenarios and the results were analysed. As a result for this project a functioning PostgreSQL database replication system was built to the Lithuanian Hydrometeorological Service's headquarters, and definite guidelines for future load balancing needs were produced. This study includes the actual implementation of a replication system to a demanding production environment, but only guidelines for building a load balancing system to the same production environment.

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The factors responsible for the phenotypic heterogeneity of memory CD4 T cells are unclear. In the present study, we have identified a third population of memory CD4 T cells characterized as CD45RA(+)CCR7(-) that, based on its replication history and the homeostatic proliferative capacity, was at an advanced stage of differentiation. Three different phenotypic patterns of memory CD4 T cell responses were delineated under different conditions of antigen (Ag) persistence and load using CD45RA and CCR7 as markers of memory T cells. Mono-phenotypic CD45RA(-)CCR7(+) or CD45RA(-)CCR7(-) CD4 T cell responses were associated with conditions of Ag clearance (tetanus toxoid-specific CD4 T cell response) or Ag persistence and high load (chronic HIV-1 and primary CMV infections), respectively. Multi-phenotypic CD45RA(-)CCR7(+), CD45RA(-)CCR7(-) and CD45RA(+)CCR7(-) CD4 T cell responses were associated with protracted Ag exposure and low load (chronic CMV, EBV and HSV infections and HIV-1 infection in long-term nonprogressors). The mono-phenotypic CD45RA(-)CCR7(+) response was typical of central memory (T(CM)) IL-2-secreting CD4 T cells, the mono-phenotypic CD45RA(-)CCR7(-) response of effector memory (T(EM)) IFN-gamma-secreting CD4 T cells and the multi-phenotypic response of both IL-2- and IFN-gamma-secreting cells. The present results indicate that the heterogeneity of different Ag-specific CD4 T cell responses is regulated by Ag exposure and Ag load.

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Over the past two decades, intermittent hypoxic training (IHT), that is, a method where athletes live at or near sea level but train under hypoxic conditions, has gained unprecedented popularity. By adding the stress of hypoxia during 'aerobic' or 'anaerobic' interval training, it is believed that IHT would potentiate greater performance improvements compared to similar training at sea level. A thorough analysis of studies including IHT, however, leads to strikingly poor benefits for sea-level performance improvement, compared to the same training method performed in normoxia. Despite the positive molecular adaptations observed after various IHT modalities, the characteristics of optimal training stimulus in hypoxia are still unclear and their functional translation in terms of whole-body performance enhancement is minimal. To overcome some of the inherent limitations of IHT (lower training stimulus due to hypoxia), recent studies have successfully investigated a new training method based on the repetition of short (<30 s) 'all-out' sprints with incomplete recoveries in hypoxia, the so-called repeated sprint training in hypoxia (RSH). The aims of the present review are therefore threefold: first, to summarise the main mechanisms for interval training and repeated sprint training in normoxia. Second, to critically analyse the results of the studies involving high-intensity exercises performed in hypoxia for sea-level performance enhancement by differentiating IHT and RSH. Third, to discuss the potential mechanisms underpinning the effectiveness of those methods, and their inherent limitations, along with the new research avenues surrounding this topic.

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Dietary acid load from Western diets may be a risk factor for osteoporosis. It can be estimated by net endogenous acid production (NEAP). No data currently exists for NEAP estimates and bone indices in the very elderly (i.e. > or = 75 y). The aim of this study was to determine the association between NEAP estimates by using the potential renal acid load (PRAL) equation and quantitative bone ultrasound (QUS) measurements at the heel [broadband ultrasound attenuation (BUA)] in Caucasian women. We assessed NEAP and QUS in 401 very elderly Swiss ambulatory women. We evaluated dietary intake and NEAP estimates with a validated FFQ. QUS was measured using Achilles (Lunar). We identified 2 subgroups: 256 women (80.6 y +/- 3; BUA, 96.8 dB/MHz) with a fracture history and the remaining 145 (79.9 y SD 2.9; BUA, 101.7 dB/MHz) without. Women who reported having suffered a fracture had lower BUA (P < 0.001) than nonfractured women but did not differ in nutrient intakes and NEAP. Lower NEAP (P = 0.023) and higher potassium intake (P = 0.033) were correlated with higher BUA, which remained significant even after adjustment for age, BMI, and osteoporosis treatment. BUA was positively correlated with calcium (P = 0.016) and BMI (P < 0.001). Women who reported no fractures had no significant correlations between nutrient intake, NEAP, and BUA. Low nutritional acid load was correlated with higher BUA in very elderly women with a fracture history. Although relatively weak compared with age and BMI, this association was significant and may be an important additional risk factor that might be particularly relevant in frail patients with an already high fracture risk.