Validade e reprodutibilidade de receptores para o GPS em relação à distância percorrida Validez y reproducibilidad de receptores GPS en relación de la distancia recorrida

ResumenObjetivoEl presente estudio evaluó la validez y reproducibilidad de dos modelos de receptores para el Global Positioning System (GPS). La validez fue evaluada comparando la distancia registrada por los receptores con la distancia conocida de estos trayectos.MétodoSeis jóvenes tenistas (177,6±6,2cm; 76,6±3,2kg) recorrieron tres trayectos: 1) 100m en la pista de atletismo (número de “disparos” = 120); 2) 400m en la pista de atletismo (número de “disparos” = 60) y 3) 100m con cambios de dirección (número de “disparos” = 120), utilizando los equipos Garmin© Forerunner 405 y Polar© RS800.ResultadosEn los trayectos sin cambios de dirección (100 y 400m), a través de la ANOVA two way (distancia y velocidad) no se detectaron diferencias entre la distancia conocida y las distancias registradas por los receptores analizados (p>0,05). En el trayecto de 100m con cambios de dirección, se observaron diferencias entre la distancia conocida y las registradas tanto por el Polar© RS800 como por el Garmin© Forerunner 405 (p<0,05). También se verificó la diferencia en las distancias registradas por el Polar® RS800 y por el Garmin© Forerunner 405 para el trayecto realizado con cambios de dirección (p<0,05).ConclusiónA través de los datos, se puede afirmar que los receptores para GPS evaluados presentaron un nivel aceptable de precisión para distancias recorridas sin cambios de dirección, sin embargo, la precisión de estos equipos en trayectos con cambios de dirección fue limitada.AbstractObjectiveThe present study evaluated the reproducibility and validity of two models of receivers for the Global Positioning System (GPS). Validity was assessed by comparing the distance recorded by the GPS receivers with the known distance.MethodSix young players (177.6±6.2cm; 76.6±3.2kg) performed three routes with different characteristics: 1) 100m in the athletics track (number of “sprints” = 120); 2) 400m in the athletics track (number of “sprints” = 60) and 3) 100m with changes of direction (number of “sprints” = 120), using equipment Garmin© Forerunner 405 and Polar© RS800.ResultsRegarding linear routes (100 and 400m), no differences were detected using ANOVA two-way (distance and speed) between the known distance and distance recorded by GPS receivers analyzed (p>0.05). Regarding non-linear route of, significant differences were observed between the known distance and recorded distance by the GPS receivers (p<0.05). There was also a significant difference between the distance recorded by Polar© RS800 and Garmin© Forerunner 405 for the non-linear route (p<0.05). Analysis of the limits of agreement reinforces the limitation of equipment in relation to accuracy for the non-linear route.ConclusionThese data suggest that the GPS receivers evaluated showed acceptable level of accuracy for linear routes, however, the accuracy of such devices on non-linear routes was limited

Asymmetries between the production of D+ and D- mesons from 500 GeV/c pi- nucleon interactions as a function of xF and pt**2

We present asymmetries between the production of D+ and D- mesons in Fermilab experiment E791 as a function of xF and pt**2. The data used here consist of 74,000 fully-reconstructed charmed mesons produced by a 500 GeV/c pi- beam on C and Pt foils. The measurements are compared to results of models which predict differences between the production of heavy-quark mesons that have a light quark in common with the beam (leading particles) and those that do not (non-leading particles). While the default models do not agree with our data, we can reach agreement with one of them, PYTHIA, by making a limited number of changes to parameters used

Mass Splitting and Production of Σc0\Sigma_c^0 and Σc++\Sigma_c^{++} Measured in 500GeV500 {GeV} π−−\pi^- -N Interactions

From a sample of $2722 \pm 78$ $\Lambda_c^+$ decaying to the $pK^-\pi^+$ final state, we have observed, in the hadroproduction experiment E791 at Fermilab, $143 \pm 20$ $\Sigma_c^0$ and $122 \pm 18$ $\Sigma_c^{++}$ through their decays to $\Lambda_c^+ \pi^{\pm}$. The mass difference $M(\Sigma_c^0) - M(\Lambda_c^+$) is measured to be $(167.38\pm 0.29\pm 0.15) {MeV}$; for $M(\Sigma_c^{++}) - M(\Lambda_c^+)$, we find $(167.76\pm 0.29\pm0.15) {MeV}$. The rate of $\Lambda_c^+$ production from decays of the $\Sigma_c$ triplet is (22\pm 2\pm 3) {%} of the total $\Lambda_c^+$ production assuming equal rate of production from all three, as measured for $\Sigma_c^0$ and $\Sigma_c^{++}$. We do not observe a statistically significant $\Sigma_c$ baryon-antibaryon production asymmetry. The $x_F$ and $p_t^2$ spectra of $\Lambda_c^+$ from $\Sigma_c$ decays are observed to be similar to those for all $\Lambda_c^+$'s produced.Comment: 15 pages, uuencoded postscript 3 figures uuencoded, tar-compressed fil

Linear competitive inhibition of human tissue kallikrein by 4-aminobenzamidine and benzamidine and linear mixed inhibition by 4-nitroaniline and aniline

Hydrolysis of D-valyl-L-leucyl-L-arginine p-nitroanilide (7.5-90.0 µM) by human tissue kallikrein (hK1) (4.58-5.27 nM) at pH 9.0 and 37ºC was studied in the absence and in the presence of increasing concentrations of 4-aminobenzamidine (96-576 µM), benzamidine (1.27-7.62 mM), 4-nitroaniline (16.5-66 µM) and aniline (20-50 mM). The kinetic parameters determined in the absence of inhibitors were: Km = 12.0 ± 0.8 µM and k cat = 48.4 ± 1.0 min-1. The data indicate that the inhibition of hK1 by 4-aminobenzamidine and benzamidine is linear competitive, while the inhibition by 4-nitroaniline and aniline is linear mixed, with the inhibitor being able to bind both to the free enzyme with a dissociation constant Ki yielding an EI complex, and to the ES complex with a dissociation constant Ki', yielding an ESI complex. The calculated Ki values for 4-aminobenzamidine, benzamidine, 4-nitroaniline and aniline were 146 ± 10, 1,098 ± 91, 38.6 ± 5.2 and 37,340 ± 5,400 µM, respectively. The calculated Ki' values for 4-nitroaniline and aniline were 289.3 ± 92.8 and 310,500 ± 38,600 µM, respectively. The fact that Ki'>Ki indicates that 4-nitroaniline and aniline bind to a second binding site in the enzyme with lower affinity than they bind to the active site. The data about the inhibition of hK1 by 4-aminobenzamidine and benzamidine help to explain previous observations that esters, anilides or chloromethyl ketone derivatives of Nalpha-substituted arginine are more sensitive substrates or inhibitors of hK1 than the corresponding lysine compounds