809 resultados para Intermittent high-intensity effort


Relevância:

100.00% 100.00%

Publicador:

Resumo:

This study aimed to investigate the effect of 830 nm low-level laser therapy (LLLT) on skeletal muscle fatigue. Ten healthy male professional volleyball players entered a crossover randomized double-blinded placebo-controlled trial. Active LLLT (830 nm wavelength, 100 mW output, spot size 0.0028 cm(2), 200 s total irradiation time) or an identical placebo LLLT was delivered to four points on the biceps humeri muscle immediately before exercises. All subjects performed voluntary biceps humeri contractions with a load of 75% of the maximum voluntary contraction (MVC) force until exhaustion. After active LLLT the mean number of repetitions was significantly higher than after placebo irradiation [mean difference 4.5, standard deviation (SD) +/- 6.0, P = 0.042], the blood lactate levels increased after exercises, but there was no significant difference between the treatments. We concluded that 830 nm LLLT can delay the onset of skeletal muscle fatigue in high-intensity exercises, in spite of increased blood lactate levels.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Al(2)O(3):Eu(3+)(1%) samples were prepared by combustion, ceramic, and Pechini methods annealed from 400 to 1400 degrees C. XRD patterns indicate that samples heated up to 1000 degrees C present disordered character of activated alumina (gamma-Al(2)O(3)). However, alpha-Al(2)O(3) phase showed high crystallinity and thermostability at 1200-1400 degrees C. The sample characterizations were also carried out by means of infrared spectroscopy (IR), scanning electron microscopy (SEM) and specific surface areas analysis (BET method). Excitation spectra of Al(2)O(3):Eu(3+) samples present broaden bands attributed to defects of Al(2)O(3) matrices and to LMCT state of O -> Eu(3+), however, the narrow bands are assigned to (7)F(0) -> (5)D(J),(5)H(J) and (5)L(J) transitions of Eu(3+) ion. Emission spectra of samples calcined up to 1000 degrees C show broaden bands for (5)D(0) -> (7)F(J) transitions of Eu(3+) ion suggesting that the rare earth ion is in different symmetry sites showed by inhomogeneous line broadening of bands, confirming the predominance of the gamma-alumina phase. For all samples heated from 1200 to 1400 degrees C the spectra exhibit narrow (5)D(0) -> (7)F(J) transitions of Eu(3+) ion indicating the conversion of gamma to alpha-Al(2)O(3) phases, a high intensity narrow peak around 695 nm assigned to R lines of Cr(3+) ion is shown. Al(2)O(3):Eu(3+) heated up to 1100 degrees C presents an increase in the Omega(2) intensity parameter with the increase of temperatures enhancing the covalent character of metal-donor interaction. The disordered structural systems present the highest values of emission quantum efficiencies (eta). CIE coordinates of Al(2)O(3):Eu(3+) are also discussed. (C) 2007 Elsevier Inc. All rights reserved.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The aim of this in vivo study was to evaluate the thermal effects caused by 810 nm 1.2 W diode laser irradiation of periodontal tissues. Despite all data available concerning the laser application for periodontal treatment, one of the most relevant challenges is to prevent the harmful tissue heating induced by different clinical protocols. Periodontal pockets were induced at molars in 96 rats. Several irradiation powers under CW mode were investigated: 0, 400, 600, 800, 1000, 1200 mW. The pockets were irradiated using a 300 A mu m frontal illumination fiber. The animals were killed at 4 or 10 days after irradiation. The mandible was surgically removed and histologically processed. The histological sections stained with H/E demonstrated that irradiation parameters up to 1000 mW were thermally safe for the periodontal tissues. The sections stained with Brown & Brenn technique evidenced bacteria in the periodontal tissues. Consequently, the diode laser irradiation as a unique treatment was not capable to eliminate bacteria of the biofilm present in the pockets. According to the methodology used here, it was concluded that the thermal variation promoted by a diode laser can cause damage to periodontal tissues depending on the energy density used. The 1.2 W diode laser irradiation itself does not control the bacteria present in the biofilm of the periodontal pockets without mechanical action. The knowledge of proper high intensity laser parameters and methods of irradiation for periodontal protocols may prevent any undesirable thermal damage to the tissues.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Physical-chemical properties of Ti are sensible to the presence of interstitial elements. In the case of thermochemical treatments plasma assisted, the influence of different active species is not still understood. In order to contribute for such knowledge, this work purposes a study of the role played by the active species atmosphere into the Ar N2 CH4 carbonitriding plasma. It was carried out a plasma diagnostic by OES (Optical Emission Spectroscopy) in the z Ar y N2 x CH4 plasma mixture, in which z, y and x indexes represent gas flow variable from 0 to 4 sccm (cm3/min). The diagnostic presents abrupt variations of emission intensities associated to the species in determined conditions. Therefore, they were selected in order to carry out the chemical treatment and then to investigate their influences. Commercial pure Ti disks were submitted to plasma carbonitriding process using pre-established conditions from the OES measurements while some parameters such as pressure and temperature were maintained constant. The concentration profiles of interstitial elements (C and N atoms) were determined by Resonant Nuclear Reaction Analysis (NRA) resulting in a depth profile plots. The reactions used were 15N(ρ,αγ)12C and 12C(α,α)12C. GIXRD (Grazing Incidence X-Ray Diffraction) analysis was used in order to identify the presence of phases on the surface. Micro-Raman spectroscopy was used in order to qualitatively study the carbon into the TiCxN1 structure. It has been verified which the density species effectively influences more the diffusion of particles into the Ti lattice and characteristics of the layer formed than the gas concentration. High intensity of N2 + (391,4 nm) and CH (387,1 nm) species promotes more diffusion of C and N. It was observed that Hα (656,3 nm) species acts like a catalyzer allowing a deeper diffusion of nitrogen and carbon into the titanium lattice.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This work introduces a new method for environment mapping with three-dimensional information from visual information for robotic accurate navigation. Many approaches of 3D mapping using occupancy grid typically requires high computacional effort to both build and store the map. We introduce an 2.5-D occupancy-elevation grid mapping, which is a discrete mapping approach, where each cell stores the occupancy probability, the height of the terrain at current place in the environment and the variance of this height. This 2.5-dimensional representation allows that a mobile robot to know whether a place in the environment is occupied by an obstacle and the height of this obstacle, thus, it can decide if is possible to traverse the obstacle. Sensorial informations necessary to construct the map is provided by a stereo vision system, which has been modeled with a robust probabilistic approach, considering the noise present in the stereo processing. The resulting maps favors the execution of tasks like decision making in the autonomous navigation, exploration, localization and path planning. Experiments carried out with a real mobile robots demonstrates that this proposed approach yields useful maps for robot autonomous navigation

Relevância:

100.00% 100.00%

Publicador:

Resumo:

A.C.P. Rodrigues-Costa, D. Martins, N.V. Costa, and M.R.R. Pereira. 2011. Spray deposition on weeds of common bean crops. Cien. Inv. Agr. 38(3): 357-365. Weed control failure in common bean (Phaseolus vulgaris L.) production may be related to inappropriate herbicide application techniques. The purpose of this study, therefore, was to evaluate the amount of spray solution deposition that occurred on the weeds, Bidens pilosa L. and Brachiaria plantaginea (Link) Hitch., both within and between rows of common beans. The research was arranged in a randomized block design with four replications. The following 6 spray nozzles were used: flat fan nozzles XR 110015 VS (150 L ha(-1)) and XR 11002 VS (200 L ha(-1)); cone nozzles TX VK 6 (150 L ha(-1)) and TX VK 8 (200 L ha(-1)); and twin flat fan nozzles TJ60 11002 VS (150 L ha(-1)) and TJ60 11002 VS (200 L ha-1). The results showed that the loss of the spray solution on the soil occurred mainly within the bean rows and with a high intensity when using a nozzle spraying 200 L ha(-1). At 30 days after sowing, the TX (150 L ha(-1)) nozzle was the only nozzle that promoted deposits of less than 210.0 mu L g(-1) of dry mass. The spray nozzles showed a good performance in the deposition of the spray solution on the weeds that occurred both within and between the rows. However, for both species there was great variation in individual deposits depending on their location in relationship to the plants.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

In northeastern semiarid, seasonality on precipitation temporal distribution, high intensity storm events and inadequate management of native vegetation can promote soil erosion. Vegetation removal causes soil surface exposure, reduces soil water storage capacity and can be the source degradation processes. In this context, this approach aims to analyze water and soil erosion processes on a 250 m2 undisturbed experimental plot with native vegetation, slope 2.5% by using 2006 and 2007 monitoring data. The site was instrumented to monitor rainfall, overland flow runoff and erosion by using a 5 m³ tank downstream the plot. Soil erosion monitoring was made by transported sediment and organic matter collection after each event. Field infiltration experiments were made at 16 points randomly distributed within the plot area by using a constant head infiltrometer during drought and rainy seasons, respectively. Infiltration data revealed high spatial and temporal variability. It was observed that during the beginning of the rainy period, 77% of the events showed runoff coefficient less than 0.05. As the rainy season began, soil water increase produced annual species germination. High intensity storms resulted in runoff coefficients varying between 0.33 and 0.42. Once the annual species was established, it was observed that approximately 39% of the events produced no runoff, which reflects an increase on soil water retention capacity caused by the vegetation. A gradual runoff reduction during the rainy season emphasizes the effect of vegetative density increase. Soil erosion observed data allowed to fit an empirical relationship involving soil loss and precipitation height, which was used to analyze the plot installation impact on soil erosion. Observed soil loss in 2006 and 2007 was 230 Kg/ha and 54 Kg/ha, respectively

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The spatial resolution improvement of orbital sensors has broadened considerably the applicability of their images in solving urban areas problems. But as the spatial resolution improves, the shadows become even a more serious problem especially when detailed information (under the shadows) is required. Besides those shadows caused by buildings and houses, clouds projected shadows are likely to occur. In this case there is information occlusion by the cloud in association with low illumination and contrast areas caused by the cloud shadow on the ground. Thus, it's important to use efficient methods to detect shadows and clouds areas in digital images taking in count that these areas care for especial processing. This paper proposes the application of Mathematical Morphology (MM) in shadow and clouds detection. Two parts of a panchromatic QuickBird image of Cuiab-MT urban area were used. The proposed method takes advantage of the fact that shadows (low intensity - dark areas) and clouds (high intensity - bright areas) represent the bottom and top, respectively, of the image as it is thought to be a topographic surface. This characteristic allowed MM area opening and closing operations to be applied to reduce or eliminate the bottom and top of the topographic surface.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Os processos de quantificação e associação das lesões do esporte aos seus possíveis fatores causais são importantes para melhor entendimento sobre assunto. Assim constituiu-se como objetivo do presente estudo a observação das lesões desportivas (LD) em atletas da elite brasileira do atletismo, associando-as aos seus mecanismos de instalação e características da modalidade. Foram entrevistados 86 atletas (47 homens e 39 mulheres) convocados para representar o Brasil durante o ano de 2003. Utilizou-se um inquérito de morbidade referida, validado anteriormente, para obtenção dos dados referentes aos atletas e suas lesões. Para a análise dos resultados adotou-se o teste de Goodman para contrastes entre e dentro de proporções binomiais, sendo todas as conclusões discutidas para 5% de significância estatística. Os resultados mostraram que há maior taxa de lesão por atleta (l/a), nas provas combinadas (3,5 l/a), seguidas por eventos de velocidade (2,6 l/a), resistência (1,9 l/a) e saltos (1,9 l/a) respectivamente. O principal mecanismo causal é a alta intensidade acometendo preferencialmente velocistas e fundistas. Outra forte associação foi observada entre lesões musculares e provas de velocidade, que também apresentam preferência para ocorrência de lesão na região da coxa. As atividades com elevada intensidade foram o principal responsável por lesões musculares, enquanto as osteoarticulares e tendinopatias ocorrem com excesso de repetições. Concluiu-se, a partir dos achados, que existem associações entre lesões e fatores causais, como entre provas e lesões, mecanismos de lesão e local anatômico.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Recent results from our laboratory have shown that 30-bites social conflict in mice produces a high-intensity, short-term analgesia which is attenuated by systemically injected 5-HT1A receptor agonists, such as BAY R 1531 (6-methoxy-4-(di-n-propylamino)-1,3,4,5-tetrahydrobenz(c,d)indole hydrochloride) and gepirone. The present study investigated the effects of these drugs, as well as the 5-HT1A receptor antagonist WAY 100135 (N-tert-butyl-3-(4-(2-methoxyphenyl)piperazine-1-yl)-2-phenylpropanamide) injected into the midbrain periaqueductal gray matter of mice on 30-bites analgesia. Four to five days after guide-cannula implantation, each mouse received microinjection of gepirone (30 nmol/0.2 mu l), BAY R 1531 (10 nmol/0.2 mu l), WAY 100135 (10 nmol/0.2 mu l), saline (0.9% NaCl) or vehicle (saline + 4% Tween 80) 5 min before either an aggressive (30 bites) or a non-aggressive interaction. Nociception was assessed by the tail-flick test made before as well as 1, 5, 10 and 20 min after social interaction. The full 5-HT1A receptor agonist BAY R 1531 blocked, whereas, WAY 100135 and gepirone intensified 30-bites analgesia, Neither non-aggressive interaction, per se, nor the three compounds given after this type of social interaction significantly changed nociception. These results indicate that 5-HT1A receptors in the periaqueductal gray inhibit analgesia induced by social conflict in mice. (C) 1998 Elsevier B.V. B.V.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Background: Pulmonary rehabilitation (PR) programs are beneficial to patients with chronic obstructive pulmonary disease (COPD), and lower-extremity training is considered a fundamental component of PR. Nevertheless, the isolated effects of each PR component are not well established. Objective: We aimed to evaluate the effects of a cycle ergometry exercise protocol as the only intervention in a group of COPD patients, and to compare these results with a control group. Methods: 25 moderate-to-severe COPD patients were evaluated regarding pulmonary function, respiratory muscle strength, exercise capacity, quality of life and body composition. Patients were allocated to one of two groups: (a) the trained group (TG; n=13; 6 men) was submitted to a protocol of 24 exercise sessions on a cycle ergometer, with training intensity initially set at a heart rate (HR) close to 80% of maximal HR achieved in a maximal test, and load increase based on dyspnea scores, and (b) the control group (CG; n=12; 6 men) with no intervention during the protocol period. Results: TG showed within-group significant improvements in endurance cycling time, 6-min walking distance test, maximal inspiratory pressure and in the domain 'dyspnea' related to quality of life. Despite the within-group changes, no between-group significant differences were observed. Conclusion: In COPD patients, the results of isolated low-to-moderate intensity cycle ergometer training are not comparable to effects of multimodality and high-intensity training programs. Copyright (C) 2004 S. Karger AG, Basel.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

There are many applications coming from geomorphological studies and their different constitutive and inter related elements, to the implementation of public politics of planning and environmental management. This search presents an analysis of the environmental fragility of the watershed of Seridó River, situated between the states of Paraíba and Rio Grande do Norte (Brazil), including the identification of possible unstable areas. It is based on the methodological approach of Ecodynamics of the French researcher J. Tricart (1977) and on the operalisation proposal advocated by the Brazilian J. Ross (1994), related to the Potential and Emerging Ecodynamic Units, grounded in the Relief s Dissection Index or the topographic roughness, soil, rainfall and land use/vegetal cover. Under a quantitative perspective, the results obtained from the analysis of the watershed can be divided into classes of potential fragility: around 2.613,0 km² of low intensity, 5.188,4 km² of medium intensity and 2.585,5 km² of high intensity. Concerning the emerging fragility, the results are close to 2.212,0 km² of low intensity, 6.191,23 km² of medium intensity and 2.062,34 km² of high intensity. In the case of the watershed in question, the environmental degradation is particularly effective in the areas more dissected, where the ecological conditions, in synergy the environmental degradation, prevent the regeneration of vegetation when arises an opportunity for the (re)establishment of its equilibrium tenuous. The collected data is relevant for the territorial and environmental planning of the watershed, once we can still verify a close association of the cities on the central area of desertification with the areas of high environmental instability/fragility. This is an important tool to the understanding of the potential susceptibility of the natural and anthropic environments related to the advance and/or intensification of the erosion process, rock falls, mass movements, among other phenomena inside the potential unstable areas. From this perspective, the continuity of this research becomes extremely important to the understanding and arrangement of the process, together with the engendering and sustainability of the system in its totality; in narrow correlation because their potentialities, constraints and alternatives on Seridó River watershed, and in all the semi-arid region with similar characteristics

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Pacientes com doença pulmonar obstrutiva crônica apresentam comumente fraqueza muscular periférica associada à intolerância ao exercício. Embora efetivo, o exercício aeróbio apresenta pouco ou nenhum efeito na fraqueza e atrofia muscular, além de não ser tolerado pela maioria dos pacientes com DPOC. Nesse sentido, o treinamento de força é opção racional para aumentar a força muscular, além de já ter se mostrado mais tolerável que o exercício aeróbio. O aumento de força muscular periférica é o benefício mais consistente do treinamento de força e, quando este é associado ao exercício aeróbio, não resulta em melhora adicional da capacidade de exercício, da dispnéia e da qualidade de vida. Contudo, observa-se que o treinamento combinado é fisiologicamente mais completo e pode ser uma opção de condicionamento físico mais diversificado. O treinamento de moderada a alta intensidade resulta em maiores adaptações fisiológicas, entretanto o exercício de baixa intensidade é tolerável, simples, de fácil execução domiciliar, não requer equipamentos sofisticados e resulta em benefícios significativos. Este exercício é indicado, sobretudo, para os pacientes com DPOC mais avançada. Finalmente, há evidências recentes de que o treinamento de força para os músculos do tronco é alternativa válida para melhorar a capacidade funcional de exercício e a função pulmonar em pacientes com DPOC. A presente revisão de literatura sugere a incorporação do treinamento de força como estratégia de rotina nos programas de reabilitação pulmonar. Pesquisas futuras são necessárias para avaliar os efeitos do treinamento de força na saúde mental, no desempenho em atividades de vida diária, na saúde osteoarticular, no risco de quedas e na função pulmonar, entre outros.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)