337 resultados para Hiperbolóide de carga e potência


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The relationships between neutrophils oxidative metabolism, cortisol serum levels and worm burden, estimated by fecal egg count (EPG), were studied in sheep naturally infected by gastrointestinal parasites at the end of pregnancy, during lactation, and after weaning. Twenty-two Suffolk sheep three to four year old, of same parity and season of parturition were used. Serum cortisol was determined by radioimmunoassay and the neutrophils oxidative metabolism by the nitroblue tetrazolium (NBT) reduction test. The highest EPG values were observed on the fifth week of lactation while the highest rates of cortisol and reduction of NBT occurred on the fourth week after weaning. A positive correlation (r = 0.52; P<0.01) was observed between the neutrophils capacity to reduce the NBT and the serum cortisol concentration in the pre-parturition period. Otherwise, the neutrophils oxidative metabolism decreased near to the parturition. A negative correlation (r = -0.39; P<0.01) between EPG and NBT reduction test was observed after weaning, which was coincident with the increase in the neutrophils capacity to reduce NBT, indicating that animals showing better immune response after weaning have neutrophils with higher oxidative metabolism and lower worm burden.

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The objective of this study was to analyze the relationship of maximal aerobic power and the muscular strength (maximal isotonic strength and vertical jump explosive power) with the running economy (RE) in endurance athletes. Twenty-six male runners (27.9 ± 6.4 years; 62.7 ± 4.3 kg; 168.6 ± 6.1 cm; 6.6 ± 3.1% of body fat) performed in different days the following tests: a) incremental test to determine the maximal oxygen uptake (V̇O2max) and the intensity corresponding to the V̇O2max (IV̇O2max); b) constant-velocity treadmill run to determine RE; c) 1-RM test in the leg press and; d) maximal vertical jump test (VJ). V̇O2max (63.8 ± 8.3 ml/kg/min) was significantly correlated (r = 0.63; p < 0.05) with RE (48.0 ± 6.6 ml/kg/min). However, the IV̇O2max (18.7 ± 1.1 km/h), the maximal isotonic strength (230.3 ± 41.2 kg) and the VJ (30.8 ± 3.8 cm) were not significantly correlated with RE. One concludes that the maximal aerobic power can explain in part the inter-individual RE variability in endurance athletes. However, maximal isotonic strength and explosive strength seem not to be associated with RE values observed in this group of athletes.

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This paper presents and discusses Ménard Pressuremeter test results used to predict bearing capacity of pounded piles installed in a tropical sandy soil. Fifteen pre-bored pressuremeter tests were carried out at the Experimental Research Site from Unesp - Bauru up to 15 m depth, one test per meter. Several laboratory and in situ tests were carried out in this research site as well as load tests on plates and on piles. Pressuremeter test results were firstly analyzed to determine geotechnical soil parameters based on empirical methods, emphasizing the estimative of the earth pressure coefficient at rest (K0). After that, bearing capacity prediction of pounded piles with 4 m, 7 m and 10 m were made and compared with test results from instrumented load tests. Pressuremeter test results allowed a very good estimative of bearing capacity for the pile with 4 m length and underestimated in 25,7% and 20,0% the bearing capacity for the pile with 7 and 10 m length, respectively. The back analysis of the test results suggests that the appropriate value for the bearing capacity factor for the tested soil-pile system on this soil is equal to 2.

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The perceived exertion has been a target of several investigations, many times with association with objective physiological indicators in exercise. Recently, the identification of the perceived exertion threshold (PET) was proposed in the water running, which presented no difference in relation to the critical velocity. Theoretically, both parameters would be indicators of the maximum steady state of variables such as V̇O2 and blood lactate. The objective of this work was to verify the coincidence between PET, critical power (PCrit) and an indicator of maximum V̇O2 steady state (PCrit') in cycle ergometer. Eight male participants were submitted to progressive effort test in order to determine V̇O2peak (46.7 ± 8.5 ml/kg/min) and to four rectangular tests until exhaustion for the estimation of the critical power model parameters, PET and PCrit'. The hyperbolic relation between mechanical power and time spent for the V̇O2peak to be reached in each test was used for the PCrit' estimation, considered as the asymptote in the power axis, and the portion of the anaerobic work capacity (CTAnaer) depleted up to the establishment of the V̇O2peak (CTAnaer'). In order to identify PET, the straight lines angular coefficients of the perceived exertion in time (ordinate) and the powers used (abscissa) were adjusted to a linear function that provided a point in the power axis in which the perceived exertion would be kept indefinitely stable. The parameters PCrit and CTAnaer were estimated by means of the power-time non-linear equation. In order to compare the estimations of PET, PCrit and PCrit', the analysis of variance ANOVA for repeated measurements was employed, and the associations were established through the Pearson correlation. CTAnaer and CTAnaer' were compared through the t test. PET (180 W ± 61 W), PCrit (174 W ± 43 W) and PCrit' (176 W ± 48 W) were not significantly different and the correlations were of 0.92-0.98. CTAnaer' (14,080 ± 5,219 J) was lower than CTAnaer (22,093 ± 9,042 J). One concludes that the PET predicts the intensity of PCrit and PCrit' with accuracy.

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The main purpose of this study was to analyze the effect of the pedaling cadence (500 × 100 rpm) on the heart rate (HR) and the blood lactate response during incremental and constant workload exercises in active individuals. Nine active male individuals (20.9 ± 2.9 years old; 73.9 ± 6.5 kg; 1.79 ± 0.9 m) were submitted to two incremental tests, and to 6-8 constant workload tests to determine the intensity corresponding to the maximal steady state lactate (MLSSintens) in both cadences. The maximal power (Pmax) attained during the incremental test, and the MLSSintens were significantly lower at 100 rpm (240.9 ± 12.6 W; 148.1 ± 154.W) compared to 50 rpm (263.9 ± 18.6 W; 186.1 ± 21.2 W), respectively. The HRmax did not change between cadences (50 rpm = 191.1 ± 8.8 bpm; 100 rpm = 192.6 ± 9.9 bpm). Regardless the cadence, the HRmax percentage (70, 80, 90, and 100%) determined the same lactate concentrations during the incremental test. However, when the intensity was expressed in Pmax percentage or in absolute power, the lactate and the HR values were always higher at highest cadences. The HR corresponding to MLSSintens was similar between cadences (50 rpm = 162.5 ± 9.1 bpm; 100 rpm = 160.4 ± 9.2 bpm). Based on these results, it can be conclude that regardless the cadence employed (50 × 100 rpm), the use of the HR to individualize the exercise intensity indicates similar blood lactate responses, and this relationship is also kept in the exercise of constant intensity performed at MLSSintens. On the other hand, the use of the Pmax percentages depend on the cadence used, indicating different physiological responses to a same percentage.

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The oral rehabilitation of the patients toothless totals presents large difficulties, because diverse factors act limiting the treatment with complete dentures conventional, as severe reabsorption of the alveolar process, generating for the phonetic patient difficulties and of mastication, annoyance, retention lack and stability of the prosthesis. With the emergence of you implant them osseointegratin idealized by Prof o Branemark, these aspects were improved by means of the possibility of new treatment options, as the overdentures tissue-implant-supported. However, the protocol of Branemark demanded a period of scaring from three to six months, owing the patients to await this time for the placement of the final prosthesis. This way, the surgical technique of immediate load was proposed to abbreviate this period, improving the transition phase, at the same time that it reduces the problems psychological associates. This way, the objective of the present study is to carry out a literature revision about the works that used overdentures comparing immediate and late load, the best alternative and factors wrapped in the success of the procedure discussing. © 2008 1995, Editorial Ciencias médicas.

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The different combination possibilities of emission uniformity and field slope within the operational unities of localized irrigation systems favor the occurence of some configurations in the irrigation system, and consequently different hydraulic head distributions, discharge and system management. After the system has been implanted, it is necessary to verify pressure and discharge distribution in the operational unit. This work objective was to verify pressure and discharge uniformity on derivation line and lateral lines with micro sprinkle in data gotten from operational research. The results allow to check that despite analyzed declivity; the higher the emission uniformity calculated for the line of derivation in the project is, the higher its pressure uniformity is. Previously the results of discharge in the emitters of the operational unit showed a constant variation entering the point of higher discharge and lower discharge, even though differently from the three tested irrigation blades.

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Background: Many studies have shown that physical exercises are able to stimulate bone formation and increase bone mass, constituting a therapeutic modality to treat bone loss due to osteoporosis. However, some points about the intensity, duration and frequency of the exercises remain confusing and contradictory. Thus, the aim of this study was to determine the effects of a progressive loading exercise program on femur of osteopenic rats. To induce osteopenia we used the animal model of ovariectomy (OVX). Forty animals was studied and divided into 4 groups: sham-operated sedentary (SS); ovariectomy-sedentary (OS); sham-operated training (ST) and ovariectomy training (OT). The trained groups performed jumps into water: 4 series of 10 jumps each, with an overload of 50% to 80% of the animal's body weight, during 8 weeks. Femora were submitted to a physical properties evaluation, a biomechanical test, calcium and phosphorus content measurement and a morphometric histological evaluation. Results: osteopenic animals showed a decrease of bone strength and lower values of bone weights, bone density and calcium content. The exercised osteopenic rats showed higher values of geometrical, physical properties, bone strength and calcium content compared to controls. The results of the present study indicate that the progressive loading exercise program had stimulatory effects on femora of osteopenic rats. It seems that the intensity and duration of the protocol used produced bone structural adaptations, which contributed to reverse bone loss due to ovariectomy.

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The tourist use of Santana cave provides a row of environmental damages, compromising partially the pristine conditions. Among the measures adopted to avoid this situation, this issue presents a contribution for the physical limits to tourist visitation and the indications for speleotouristic management. It was used the Cifuentes Carrying Capacity method and some basic principles of Visitors Impact Management Framework - VIM. The results show a Real Carrying Capacity (CCR) about 120 visits daily on the cave. The discussions raise a few hypotheses about the alteration in the method used and the temporal frequency between visitors groups, suggesting a provisional CCR of 117 and 135 visitors daily, respectively, during the week and in the weekends and holidays. The conclusions appoint the necessity of a conceptual revision in the Carrying Capacity methods, mainly about its adaptation for tourist management in caves. In the case studied, it is suggested the immediate beginning of environmental monitoring of the cave, to verify the plausibility from proposed visitation limits and the possible contributions for to mitigate the environmental impacts from speleotourism.

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This paper proposes and describes a high power factor AC-AC converter for naval applications using Permanent Magnet Generator (PMG). The three-phase output voltages of the PMG vary from 260 Vrms (220 Hz) to 380 Vrms (360 Hz), depending on load conditions. The proposed converter consists of a Y-/ΔY power transformer, which provides electrical isolation between the PMG and remaining stages, and a twelve-pulse uncontrolled rectifier stage directly connected to a single-phase inverter stage, without the use of an intermediary DC-DC topology. This proposal results in more simplicity for the overall circuitry, assuring robustness, reliability and reduced costs. Furthermore, the multipulse rectifier stage is capable to provide high power factor and low total harmonic distortion for the input currents of the converter. The single-phase inverter stage was designed to operate with wide range of DC bus voltage, maintaining 120 Vrms, 60 Hz output. The control philosophy, implemented in a digital signal processor (DSP) which also contains protection routines, alows series connections between two identical converters, achieving 240 Vrms, 60 Hz total output voltage. Measured total harmonic distortion for the AC output voltage is lower than 2% and the input power factor is 0.93 at 3.6kW nominal load. © 2010 IEEE.

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This paper aims to determine the importance of emitter ́s local head loss in the hydraulic design of hose drip lines, as well as comparing the result of equations that calculate the local head loss; besides verifying the influence of iron precipitated at the hose head loss made in Brazil. The result found that localized head loss represents 23% of the total head loss; the equations showed significant results and the total head loss increased in an average of 20% after the irrigation system was used with water rich in iron.

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In this paper the point estimation method is applied to solve the probabilistic power flow problem for unbalanced three-phase distribution systems. Through the implementation of this method the probability distribution functions of voltages (magnitude and angle) as well as the active and reactive power flows in the branches of the distribution system are determined. Two different approaches of the point estimation method are presented (2m and 2m+1 point schemes). In order to test the proposed methodology, the IEEE 34 and 123 bus test systems are used. The results obtained with both schemes are compared with the ones obtained by a Monte Carlo Simulation (MCS).

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The suspension of rats by the tail model is used to investigate the behavior of bone in animals unable to move around. Bone is an adaptative tissue that develops in structure and function, among other factors, in response to mechanical forces applied to it and metabolic demands that it will suffer. The absence of mechanical forces and deformation of bone that occurs causes a decrease in calcium deposition in the absence of stimuli on osteoblasts and osteocytes, favoring the action of osteoclasts, making bones weak and brittle. Therefore, the mechanical action is necessary to stimulate local bone response and thus provide growth and remodeling. The aim of this study was to evaluable by radiographic densitometry, the tail suspension for 15 and 36 days alter the bone mineral density of cervical vertebrae (C3), thoracic (T6) and lumbar (L1 and L3) of Wistar rats. Thirty Rattus norvegicus albinus, adult, male, Wistar strain, average body mass ± 350g, were divided into 3 groups: control (n = 10) - not suspended; S15 (n = 10) - suspended for 15 days and S36 (n = 10) - suspended for 36 days. For densitometric analysis vertebrae were radiographed, scanned, digitized and analyzed by the computer program ImageJ®. There was a statistically significant increase in bone mineral density in group S15, probably by the restlessness of the animals to the suspension, with a decrease in group S36, and this hypothetically is linked to the accommodation of the rats, concluding that the tail suspension altered bone mineral density in first time with a decrease over time.

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The maximal oxygen uptake (VO2max) is the maximal quantity of energy that can be produced by the aerobic metabolism in certain time unity. It can be determined direct or indirectly by predictive equations. The objective of this study was to make a specific predictive equation to determine the VO 2max from boys aged 10-16 years-old. Forty-two boys underwent a treadmill running ergospirometric test, with the initial velocity set at 9 km/h, until voluntary exhaustion. By the multiple linear regression was possible to develop the following equation for the indirect determination of the VO 2max: VO2max (ml/min) = -1574.06 + (141.38 x Vpeak) + (48.34 * Body mass), with standard error of estimate = 191.5 ml/min (4.10 ml/kg/min) and coefficient of determination = 0.934. We suggest that this formula is appropriate to predict VO2max for this population.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)