968 resultados para fission-track


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

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The Portalegre shear zone (ZCPa), which is located in the Rio Grande do Norte and Paraíba states (Northeastern Brazil), is na important right-lateral, northeast-trending lineament formed during the Brazilian Orogenic Cicle). The ZCPa experienced na important brittle reactivation from the Mesozoic until the present. This reactivation led to the formation of the Gangorra, Pau dos Ferros, Coronel João Pessoa, Icozinho and Rio do Peixe basins. The reactivation northern parto f the ZCPa that marks the boundary of the Potiguar Basin is denominated Carnaubais Fault. Several fracture patterns were mapped along the ZCPa. Samples were collected in Neoproterozoic granite outcrops, along the ZCPa. These samples yielded AFT ages from 86±13 to 376±57 Ma, and the mean track length from 10.9±0.8 to 12.9±1.5 mm. Samples from the East block yielded mean ages of 103 Ma, mean track lengtn 12,1mm, and mean altitude 250m, whereas samples from West block yielded mean ages of 150 Ma, which reach 345 Ma and 220 Ma in the Pau dos Ferros and Coronel João Pessoa basins, respectively. Thermal history models were sorted out for each crustal block. Samples from West block recorded a thermal history from Carboniferous Period until the Permiano, when the block experienced gradual uplift until the Cretaceous, when it underwent downfaulting and heating until the Tertiary, and it eventually experienced a rapid uplift movement until recent times. Samples from the East block presented the same cooling and heating events, but at they occurred different times. The East block thermal record started ~140 Ma, when this block experienced cooling until ~75 Ma. Both blocks show a denundacion/erosional history more similar in the Tertiary. The AFT data indicate an important tectonic event ~140 Ma, when the West block experienced downfaulting and the East block experienced uplift. This tectonic process led to the generation of several sedimentary basins in the region, including the Potiguar basin. This tectonic event is also interpreted as a rift process caused by an E-W-trending extension. It the Tertiary, some heating events can be tentatively attributed to the macau volcanic event

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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The equilibrium point between blood lactate production and removal (La-min(-)) and the individual anaerobic threshold (IAT) protocols have been used to evaluate exercise. During progressive exercise, blood lactate [La-](b), catecholamine and cortisol concentrations, show exponential increases at upper anaerobic threshold intensities. Since these hormones enhance blood glucose concentrations [Glc](b), this study investigated the [Glc] and [La-](b) responses during incremental tests and the possibility of considering the individual glucose threshold (IGT) and glucose minimum;(Glc(min)) in addition to IAT and La-min(-) in evaluating exercise. A group of 15 male endurance runners ran in four tests on the track 3000 m run (v(3km)); IAT and IGT- 8 x 800 m runs at velocities between 84% and 102% of v(3km); La-min(-) and Glc(min) - after lactic acidosis induced by a 500-m sprint, the subjects ran 8 x 800 m at intensities between 87% and 97% of v(3km); endurance test (ET)- 30 min at the velocity of IAT. Capillary blood (25 mu l) was collected for [La-](b) and [Glc](b) measurements. The TAT and IGT were determined by [La-](b) and [Glc](b) kinetics during the second test. The La-min(-) and Glc(min) were determined considering the lowest [La-] and [Glc](b) during the third test. No differences were observed (P < 0.05) and high correlations were obtained between the velocities at IAT [283 (SD 19) and IGT 281 (SD 21)m. min(-1); r = 0.096; P < 0.001] and between La,, [285 (SD 21)] and Glc(min) [287 (SD 20) m. min(-1) = 0.77; P < 0.05]. During ET, the [La-](b) reached 5.0 (SD 1.1) and 5.3 (SD 1.0) mmol 1(-1) at 20 and 30 min, respectively (P > 0.05). We concluded that for these subjects it was possible to evaluate the aerobic capacity by IGT and Glc(min), as well as by IAT and La-min(-).

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The end magnets of the IFUSP race-track microtron booster, second stage of the electron accelerator under construction at the Linear Accelerator Laboratory, are presented. They deflect, focus and return the beam to the accelerating section. Details about the project are discussed, Poisson code was used to give the final geometry of the end magnets. The end magnets incorporate auxiliary pole pieces (clamps) which create a reverse fringe field region that avoids the beam vertical defocusing and reduces the horizontal displacement produced by extended fringe fields (EFF). The small gap height used for the clamps provided reverse field distributions with fringe fields of short extensions, avoiding the traditional use of inactive clamps. Measurements and calculations concerning particle trajectories and reverse field distribution are presented. The floating wire technique, employing an original procedure to register orbits, was used to corroborate the calculated beam trajectories and represents a good experimental option in the lack of the accelerator beam. The experimental results showed agreement of about 0.1% with the calculations.

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The running velocities associated to lactate minimum (V-lm), heart rate deflection (V-HRd), critical velocity (CV), 3000 M (V-3000) and 10000 m performance (V-10km) were compared. Additionally the ability of V-lm and VHRd on identifying sustainable velocities was investigated.Methods. Twenty runners (28.5 +/- 5.9 y) performed 1) 3000 m running test for V3000; 2) an all-out 500 in sprint followed by 6x800 m incremental bouts with blood lactate ([lac]) measurements for V-lm; 3) a continuous velocity-incremented test with heart rate measurements at each 200 m for V-HRd; 4) participants attempted to 30 min of endurance test both at V-lm(ETVlm) and V-HRd(ETVHRd). Additionally, the distance-time and velocity-1/time relationships produced CV by 2 (500 m and 3000 m) or 3 predictive trials (500 m, 3000 m and distance reached before exhaustion during ETVHRd), and a 10 km race was recorded for V-10km.Results. The CV identified by different methods did not differ to each other. The results (m(.)min(-1)) revealed that V-.(lm) (281 +/- 14.8)< CV (292.1 +/- 17.5)=V-10km (291.7 +/- 19.3)< V-HRd (300.8 +/- 18.7)=V-3000 (304 +/- 17.5) with high correlation among parameters (P < 0.001). During ETVlm participants completed 30 min of running while on the ETVHRd they lasted only 12.5 +/- 8.2 min with increasing [lac].Conclusion. We evidenced that CV and Vim track-protocols are valid for running evaluation and performance prediction and the parameters studied have different significance. The V-lm reflects the moderate-high intensity domain (below CV), can be sustained without [lac] accumulation and may be used for long-term exercise while the V-HRd overestimates a running intensity that can be sustained for long-time. Additionally, V-3000 and V-HRd reflect the severe intensity domain (above CV).

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The objective of this study was to determine the critical speed (CS) for track cycling and to assess whether a lactate steady state occurs at this speed. Fourteen competitive cyclists performed the following tests on an official cycling track (333.3 m): 1) incremental test for determination of the intensity corresponding to 4 mM of blood lactate (onset of blood lactate accumulation, OBLA) and maximal oxygen uptake (VO(2)max); 2) CS: 3 maximal bouts for distances of 2, 4 and 6 km executed in random order and with a period of recovery of 40 to 50 min between bouts. CS was determined for each subject from the linear regression between the distance and the time taking to cycle it; 3) Endurance test in which subjects were instructed to pedal at 100% of their individually determined CS for 30 min. At the 10(th) and 30(th) min (or upon exhaustion), 25 mul of blood were collected from ear lobe for later analysis of blood lactate [Lac]b. An increase less than or equal to1 mM between 10 and 30 min of exercise was considered as the criterion for the occurrence of the lactate steady state. CS (49.6 +/- 8.6 ml.kg(-1).min(-1); 36.9 +/- 2.7 km.h(-1)) was significantly higher than OBLA (43.7 8.0 ml.kg(-1).min(-1); 35.24 +/- 2.6 km.h(-1)) although the two parameters were highly correlated (r=0.97). During the endurance test, only 8 of the 14 subjects completed the 30 min period at CS. of these 8 subjects, only 2 presented a lactate steady state. Time to exhaustion at CS was 20.3 +/- 1.6 min for the remaining 6 subjects. The 12 subjects who did not reach a lactate steady state presented mean [Lac]b values of 7.4 +/- 1.3 mM at 10 min and of 9.4 +/- 1.9 mM at the end of the test (exhaustion), characterizing an exercise intensity of high lactacidemia. on the basis of the present results, we can conclude that CS determined by a track cycling test seems to overestimate the intensity of the maximal lactate steady state for most subjects.

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We will present measurements and calculations related to the antisymmetric perturbations, and comparisons with the symmetric ones, of the IFUSP race-track microtron booster accelerator end magnets. These perturbations were measured in planes situated at +/-12 mm of the middle plane, in a gap height of 4 cm, for a field distribution of about 0.1 T. The measurements were done in 1170 points, separated by a distance of 8 mm, using an automated system with a +/-1.5 mu T differential Hall probe. The race-track microtron booster is the second stage of the 30.0 MeV electron accelerator under construction at the Linear Accelerator Laboratory in which the required uniformity for the magnetic field is of about 10(-3). The method of correction employed to homogenize the IFUSP race-track microtron booster accelerator magnets assures uniformity of 10(-5) in an average field of 0.1 T, over an area of 700 cm(2). This method uses the principle of attaching to the pole pieces correction coils produced by etching techniques, with copper leads shaped like the isofield lines of the normal component of the magnetic field measured. The ideal planes, in which these measurements are done, are calculated and depend on the behavior of the magnetic field perturbations: symmetric or antisymmetric with reference to the middle plane of the magnet gap. These calculations are presented in this work and show that for antisymmetric perturbations there is no ideal plane for the correction of the magnetic field; for the symmetric one, these planes are at +/-60% of the half gap height, from the middle plane. So this method of correction is not feasible for antisymmetric perturbations, as will be shown. Besides, the correction of the symmetric portion of the field distribution does not influence the antisymmetric one, which almost does not change, and corroborates the theoretical predictions. We found antisymmetric perturbations of small intensity only in one of the two end magnets. However, they are not detected at +/- 1 mm of the middle plane and will not damage the electron beam.

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This paper is the result of real-scale physical modeling study designed to simulate the load-deformation characteristics of railroad foundation systems that include the railroad ties, the ballast, and the sub-base layers of a railroad embankment. The study presents comparisons of the application of dynamic loads of 100kN on the rails, and the resulting deformations during a 500,000 cycle testing period for three rail support systems; wood, concrete and steel. The results show that the deformation curve has an exponential shape, with the larger portion of the deformation occurring during the first 50,000 load cycles followed by a tendency to stabilize between 100,000 to 500,000 cycles. These results indicate that the critical phase of deformations of a new railroad is within the first 50,000 cycles of loading, and after that, it slowly attenuates as it approaches a stable value. The paper also presents empirically derived formulations for the estimation of the deformations of the rail supports as a result of rail traffic.

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Reasons for performing study: To our knowledge no studies evaluating risk factors to EIPH have been undertaken with such a population of horses in Brazil, which is one of the few countries in the racing community to accept the use of frusemide (FUR) as a prerace medication for bleeders. We also compared national results with those already in the literature. Objectives: To verify the influence of variables such as distance of the race, racetrack surface, going and season of the year in the recurrence and severity of EIPH and its effect on the finishing position of flat racing Thoroughbreds in Brazil. Methods: 2118 post race respiratory endoscopies were recorded, in a total of 1003 individual horses. All horses in the study were certified bleeders (deemed positive by registered veterinarians following one or more endoscopies) and were administered FUR prior to each race. Data was analysed using both ordinary logistic regression and multiple logistic regression. Results: The results suggest that race distance, season of the year and racetrack surface affect the recurrence of EIPH. Also, despite the use of FUR, the majority (62%) of horses continued to display some degree of haemorrhage. Conclusions: There was a tendency for horses that remained positive despite the use of FUR to finish unplaced in a race. Horses which had a significant reduction in bleeding and became HPIE negative after the use of FUR, tended to finish in top positions. It was not possible to determine a pattern of severity of EIPH in horses with more than one endoscopy. Further studies are required to improve our understanding of this syndrome and its correlations to performance in the racing Thoroughbred, together with the role of FUR and its possible enhancing performance effects and efficacy in consistently diminishing EIPH. Potential relevance: This study enabled a better understanding of the use of FUR in Brazilian Thoroughbred racehorses and showed there was a tendency towards improvement in performance after administrion of FUR in bleeders. The fact that a large number of horses remained positive for EIPH despite the use of FUR should encourage the scientific community to search for better ways of reducing, or preventing, this syndrome. © 2006 EVJ Ltd.

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This paper analyses the static and dynamic behavior of the railroad track model in laboratory. Measurements of stresses and strains on a large-scale railroad track apparatus were studied. The model includes: compacted soil, representing the final layers of platform, ballast layer, and ties (steel, wooden, and pre-stressed concrete). The soil and soil ballast interface were instrumented with pneumatic stress gauge. Settlement measurement device were positioned at the same levels as the load cells. Loads were applied by hydraulic actuators, statically and dynamically. After the prescribed number of load cycles, in pre-determined intervals, stresses and strains were measured. Observations indicate that stress and strain distributions, transmitted by wooden or steel ties, behave similarly. A more favorable behavior was observed with pre-stressed concrete mono block ties. Non-linear response was observed after a threshold numbers of cycles were surpassed, showing that the strain modulus increases with the numbers of cycles. © 2009 IOS Press.

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

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

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A description is provided of the software algorithms developed for the CMS tracker both for reconstructing charged-particle trajectories in proton-proton interactions and for using the resulting tracks to estimate the positions of the LHC luminous region and individual primary-interaction vertices. Despite the very hostile environment at the LHC, the performance obtained with these algorithms is found to be excellent. For t (t) over bar events under typical 2011 pileup conditions, the average track-reconstruction efficiency for promptly-produced charged particles with transverse momenta of p(T) > 0.9GeV is 94% for pseudorapidities of vertical bar eta vertical bar < 0.9 and 85% for 0.9 < vertical bar eta vertical bar < 2.5. The inefficiency is caused mainly by hadrons that undergo nuclear interactions in the tracker material. For isolated muons, the corresponding efficiencies are essentially 100%. For isolated muons of p(T) = 100GeV emitted at vertical bar eta vertical bar < 1.4, the resolutions are approximately 2.8% in p(T), and respectively, 10 m m and 30 mu m in the transverse and longitudinal impact parameters. The position resolution achieved for reconstructed primary vertices that correspond to interesting pp collisions is 10-12 mu m in each of the three spatial dimensions. The tracking and vertexing software is fast and flexible, and easily adaptable to other functions, such as fast tracking for the trigger, or dedicated tracking for electrons that takes into account bremsstrahlung.

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Pós-graduação em Engenharia Mecânica - FEIS