858 resultados para physiological requirements


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The aim of this study is to analyse the physical and physiological factors in soccer training at different categories of training. The participants were 30 soccer players of 8-aside soccer in the under 10’s age group (9.93±0.25 years) who participated in the under 10 Provincial Tournament in Alicante. During training, the variables of covered distance, heart rate, speed (average and maximum values) as well as the methodology used and position were registered. After the statistical analysis and its related discussion, it was concluded that the players do not show differences in the covered total distance in relation to the category. Notwithstanding, there are differences with regards to speed and heart rate, which are caused by the greater physical development of the players in comparison to the under10’s age group category. Regarding the methodology employed, it is worth stressing that the coaches used, to a greater extend, the global method, followed by the mixed method.

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Tese de doutoramento, Biologia (Biologia Marinha e Aquacultuta), Universidade de Lisboa, Faculdade de Ciências, 2014

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Although table tennis has a tradition lasting more than 100 years, relatively little is known about players' physiological requirements - especially during competition. In this review we discuss research studies that have led to our current understanding of how the body functions during table tennis training and competition and how this is altered by training. Match and practice analysis of the table tennis game indicates that during intense practice and competition it is predominantly the anaerobic alactic system that is called into play, while the endurance system is relied on to recovery the anaerobic stores used during such effort. It is thus important for coaches to keep in mind that, while the anaerobic alactic system is the most energetic system used during periods of exertion in a table tennis game, a strong capacity for endurance is what helps a player recover quicker for the following match and the next day of competition. This paper provides a review of specific studies that relate to competitive table tennis, and highlights the need for training and research programs tailored to table tennis. © Journal of Sports Science and Medicine.

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Expanded understanding of the trends and determinants of food consumption is needed to reduce the ecological impacts of the contemporary agro-food system while also being attentive to broader issues pertaining to health and the environment. Incorporating these additional aspects and formulating meaningful dietary recommendations is a major challenge. This article seeks to highlight differences in ecological footprint (EF) by activity level for various so-cial groups to meet suggested physiological requirements by nutritionists versus actual food consumption. The study is based on a combination of healthy diet requirements (as expressed by national guidelines) and a survey of a repre-sentative sample of 1,013 Hungarian adults using a bottom-up approach for calculating EFs. Students and women with small children have a higher than average food-related EF due to their higher nutritional needs. At the same time, the elderly are characterized by lower footprints. Perhaps most interesting is our finding that people with seden-tary forms of employment have higher food footprints than those with jobs that require physical labor. We offer rec-ommendations for food-policy planning based on encouraging dietary changes for individuals, differentiated by the nature of their work. The research suggests that dietary policy that improves health often has environmental benefits.

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Undernutrition is common in patients admitted for surgery and is often unrecognised, untreated and worsens in hospital. The complex synergistic relationship between nutritional status and the physiological responses to surgery puts patients at high nutritional risk. There are clear prospective associations between inadequate nutritional status and the risk of poorer outcomes for surgical patients, including infection, complications and length of stay. However, practically and ethically evidence that nutritional interventions can significantly reduce these poor outcomes is difficult to obtain. Nevertheless health professionals have a duty of care to ensure our patients are properly fed, by whatever means, to meet their physiological requirements.

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Male flowering was studied at the canopy level in 10 silver birch (Betula pendula Roth) stands from 8 localities and in 14 downy birch (B. pubescens Ehrh.) stands from 10 localities in Finland from 1963 to 1973. Distributions of cumulative pollen catches were compared to the normal Gaussian distribution. The basis for the timing of flowering was the 50 per cent point of the anthesis-fitted normal distribution. To eliminate effects of background pollen, only the central, normally distributed part of the cumulative distribution was used. Development up to the median point of the distribution was measured and tested in calendar days, in degree days (> 5 °C) and in period units. The count of each parameter began on and included March 19. Male flowering in silver birch occurred from late April to late June depending on latitude, and flowering in downy birch took place from early May to early July. The heat sums needed for male flowering varied in downy birch stands latitudinally but there was practically no latitudinal variation in heat sums needed for silver birch flowering. The amount of male flowering in stands of both birch species were found to have a large annual variation but without any clear periodicity. The between years pollen catch variation in stands of either birch species did not show any significant latitudinal correlation in contrast to Norway spruce stands. The period unit heat sum gave the most accurate forecast of the timing of flowering for 60 per cent of the silver birch stands and for 78.6 per cent of the for downy birch stands. Calendar days, however, gave the best forecast for silver birch in 25 per cent of the cases, while degree days gave the best forecast for downy birch in 21.4 per cent of the cases. Silver birch seems to have a local inclination for a more fixed flowering date compared to downy birch, which could mean a considerable photoperiodic influence on flowering time of silver birch. Silver birch and downy birch had different geographical correlations. Frequent hybridization of birch species occurs more often in northern Finland in than in more southern latitudes. The different timing in flowering caused increasing scatter in flowering times in the north, especially in the case of downy birch. The chance of simultaneous flowering of silver birch and downy birch so increased northwards due to a more variable climate and also higher altitudinal variations. Compared with conifers, the reproduction cycles of both birch species were found to be well protected from damage by frost.

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An article explaining how the methods and results from the time spent by the author culturing algae can be applied to other algal investigations. The work by the author found that physiological requirements differ widely among algae belonging to different systematic groups. Details are given of the results of a series of experiments which were undertaken in solutions with similar proporties to some natural waters in the Lake District. Reference is made to a paper under preparation at that time containing data on phytoplankton studied in the field within the Lake District during 1937. Reference is also made to Loch Leven and the affects of bluegreen alga on the number of trout caught weekly during 1937.

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Suspended particulate matter (SPM), sediments and clams were collected at three sites in Jiaozhou Bay to assess the magnitude of trace metal pollution in the area. Metal concentrations in SPM (Cu: 40.11-203; Zn: 118-447; Pb: 50.1-132; Cd: 0.55-4.39; Cr: 147.6-288; Mn: 762-1670 mu g/g), sediments (Cu: 17.64-34.26; Zn: 80.79-110; Pb: 24.57-49.59; Cd: 0.099-0.324; Cr: 41.6-88.1; Mn: 343-520 mu g/g) and bivalves (Cu: 6.41-19.76; Zn: 35.5-85.5; Pb: 0.31-1.01; Cd: 0.51-0.67; Mn: 27.45-67.6 mu g/g) are comparable to those reported for other moderately polluted world environments. SPM showed a less clear pattern. Metal concentrations in sediments displayed a clear geographical trend with values increasing with proximity to major urban centers. The clams (on dry weight) showed a complex pattern due to the variability introduced by age-related factors. Cd showed an apparent reverse industrial trend with higher concentrations in clams collected at distant stations. Zn, Pb and Mn showed no clear geographical pattern, whereas Cu increased in the clams collected in the most industrialized area. In addition, the bioaccumulation factors (BAF) were calculated. The result indicated that the studied Ruditapes philippinarum in Jiaozhou Bay possessed different bioaccumulation capacities for Cd, Zn, Cu, Pb and Mn, and Cd, Zn had a relatively high assimilation of those metals from sediment particles. A significant relationship with clam age was observed for Zn (positive) and Cu (negative) suggesting different physiological requirements for both metals with age. Trace metal concentrations measured in the tissue of the investigated clam were in the range considered safe by the WHO for human use.

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There is evidence that active, pre-emergence maternal brood care in amphipod crustaceans may be associated with 'harsh' environmental conditions. We examined, in the rockpool amphipod Apherusa jurinei, behavioural activities that may function as a form of active brood care. Only ovigerous females showed 'curl' and 'stretch' activities, with consequent flushing of the brood pouch and cycling of the eggs therein. There was a significant decline in these activities as embryonic development advanced and brood care almost ceased when well-developed embryos showed a heart pulse and self-ventilation. We propose that this pattern of brood care reflects changes in the physiological requirements of embryos as they develop within the egg membrane. In addition, ovigerous females showed significantly higher levels of brood care under lowered oxygen conditions. They achieved this by increasing the average duration of the 'stretch' component, with other brood care components remaining constant. Thus, developmental and environmental cues alter the components of active brood care in distinct ways. Experimental removal showed that the physical presence of eggs in the brood pouch is important in controlling the expression of brood care activities. However, females with all of their eggs removed continued to brood at low levels, suggesting that a maternal state also controls brood care. The sophisticated expression of active maternal brood care in amphipods under 'harsh' environmental conditions such as rockpools has implications both for individual reproductive success and the distribution and abundance of brooding versus nonbrooding species. (C) 2002 Published by Elsevier Science Ltd on behalf of The Association for the Study of Animal Behaviour.

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Para las decisiones urgentes sobre intervenciones quirúrgicas en el sistema cardiovascular se necesitan simulaciones computacionales con resultados fiables y que consuman un tiempo de cálculo razonable. Durante años los investigadores han trabajado en diversos métodos numéricos de cálculo que resulten atractivos para los cirujanos. Estos métodos, precisos pero costosos desde el punto de vista del coste computacional, crean un desajuste entre la oferta de los ingenieros que realizan las simulaciones y los médicos que operan en el quirófano. Por otra parte, los métodos de cálculo más simplificados reducen el tiempo de cálculo pero pueden proporcionar resultados no realistas. El objetivo de esta tesis es combinar los conceptos de autorregulación e impedancia del sistema circulatorio, la interacción flujo sanguíneo-pared arterial y modelos geométricos idealizados tridimensionales de las arterias pero sin pérdida de realismo, con objeto de proponer una metodología de simulación que proporcione resultados correctos y completos, con tiempos de cálculo moderados. En las simulaciones numéricas, las condiciones de contorno basadas en historias de presión presentan inconvenientes por ser difícil conocerlas con detalle, y porque los resultados son muy sensibles ante pequeñas variaciones de dichas historias. La metodología propuesta se basa en los conceptos de autorregulación, para imponer la demanda de flujo aguas abajo del modelo en el ciclo cardiaco, y la impedancia, para representar el efecto que ejerce el flujo en el resto del sistema circulatorio sobre las arterias modeladas. De este modo las historias de presión en el contorno son resultados del cálculo, que se obtienen de manera iterativa. El método propuesto se aplica en una geometría idealizada del arco aórtico sin patologías y en otra geometría correspondiente a una disección Stanford de tipo A, considerando la interacción del flujo pulsátil con las paredes arteriales. El efecto de los tejidos circundantes también se incorpora en los modelos. También se hacen aplicaciones considerando la interacción en una geometría especifica de un paciente anciano que proviene de una tomografía computarizada. Finalmente se analiza una disección Stanford tipo B con tres modelos que incluyen la fenestración del saco. Clinicians demand fast and reliable numerical results of cardiovascular biomechanic simulations for their urgent pre-surgery decissions. Researchers during many years have work on different numerical methods in order to attract the clinicians' confidence to their colorful contours. Though precise but expensive and time-consuming methodologies create a gap between numerical biomechanics and hospital personnel. On the other hand, simulation simplifications with the aim of reduction in computational time may cause in production of unrealistic outcomes. The main objective of the current investigation is to combine ideas such as autoregulation, impedance, fluid-solid interaction and idealized geometries in order to propose a computationally cheap methodology without excessive or unrealistic simplifications. The pressure boundary conditions are critical and polemic in numerical simulations of cardiovascular system, in which a specific arterial site is of interest and the rest of the netwrok is neglected but represented by a boundary condition. The proposed methodology is a pressure boundary condition which takes advantage of numerical simplicity of application of an imposed pressure boundary condition on outlets, while it includes more sophisticated concepts such as autoregulation and impedance to gain more realistic results. Incorporation of autoregulation and impedance converts the pressure boundary conditions to an active and dynamic boundary conditions, receiving feedback from the results during the numerical calculations and comparing them with the physiological requirements. On the other hand, the impedance boundary condition defines the shapes of the pressure history curves applied at outlets. The applications of the proposed method are seen on idealized geometry of the healthy arotic arch as well as idealized Stanford type A dissection, considering the interaction of the arterial walls with the pulsatile blood flow. The effect of surrounding tissues is incorporated and studied in the models. The simulations continue with FSI analysis of a patient-specific CT scanned geometry of an old individual. Finally, inspiring of the statistic results of mortality rates in Stanford type B dissection, three models of fenestrated dissection sac is studied and discussed. Applying the developed boundary condition, an alternative hypothesis is proposed by the author with respect to the decrease in mortality rates in patients with fenestrations.

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The use of macroalgae (seaweed) as a potential source of biofuels has attracted considerable worldwide interest. Since brown algae, especially the giant kelp, grow very rapidly and contain considerable amounts of polysaccharides, coupled with low lignin content, they represent attractive candidates for bioconversion to ethanol through yeast fermentation processes. In the current study, powdered dried seaweeds (Ascophylum nodosum and Laminaria digitata) were pre-treated with dilute sulphuric acid and hydrolysed with commercially available enzymes to liberate fermentable sugars. Higher sugar concentrations were obtained from L. digitata compared with A. nodosum with glucose and rhamnose being the predominant sugars, respectively, liberated from these seaweeds. Fermentation of the resultant seaweed sugars was performed using two non-conventional yeast strains: Scheffersomyces (Pichia) stipitis and Kluyveromyces marxianus based on their abilities to utilise a wide range of sugars. Although the yields of ethanol were quite low (at around 6 g/L), macroalgal ethanol production was slightly higher using K. marxianus compared with S. stipitis. The results obtained demonstrate the feasibility of obtaining ethanol from brown algae using relatively straightforward bioprocess technology, together with non-conventional yeasts. Conversion efficiency of these non-conventional yeasts could be maximised by operating the fermentation process based on the physiological requirements of the yeasts.

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Older drivers represent the fastest growing segment of the road user population. Cognitive and physiological capabilities diminishes with ages. The design of future in-vehicle interfaces have to take into account older drivers' needs and capabilities. Older drivers have different capabilities which impact on their driving patterns and subsequently on road crash patterns. New in-vehicle technology could improve safety, comfort and maintain elderly people's mobility for longer. Existing research has focused on the ergonomic and Human Machine Interface (HMI) aspects of in-vehicle technology to assist the elderly. However there is a lack of comprehensive research on identifying the most relevant technology and associated functionalities that could improve older drivers' road safety. To identify future research priorities for older drivers, this paper presents: (i) a review of age related functional impairments, (ii) a brief description of some key characteristics of older driver crashes and (iii) a conceptualisation of the most relevant technology interventions based on traffic psychology theory and crash data.

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Ascorbic acid or vitamin C is involved in a number of biochemical pathways that are important to exercise metabolism and the health of exercising individuals. This review reports the results of studies investigating the requirement for vitamin C with exercise on the basis of dietary vitamin C intakes, the response to supplementation and alterations in plasma, serum, and leukocyte ascorbic acid concentration following both acute exercise and regular training. The possible physiological significance of changes in ascorbic acid with exercise is also addressed. Exercise generally causes a transient increase in circulating ascorbic acid in the hours following exercise, but a decline below pre-exercise levels occurs in the days after prolonged exercise. These changes could be associated with increased exercise-induced oxidative stress. On the basis of alterations in the concentration of ascorbic acid within the blood, it remains unclear if regular exercise increases the metabolism of vitamin C. However, the similar dietary intakes and responses to supplementation between athletes and nonathletes suggest that regular exercise does not increase the requirement for vitamin C in athletes. Two novel hypotheses are put forward to explain recent findings of attenuated levels of cortisol postexercise following supplementation with high doses of vitamin C.