161 resultados para Threshold VAR
Resumo:
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(-).
Resumo:
The objectives of the current study were to assess the feasibility of using stayability traits to improve fertility of Nellore cows and to examine the genetic relationship among the stayabilities at different ages. Stayability was defined as whether a cow calved every year up to the age of 5 (Stay5), 6 (Stay6), or 7 (Stay7) yr of age or more, given that she was provided the opportunity to breed. Data were analyzed based on a maximum a posteriori probit threshold model to predict breeding values on the liability scale, whereas the Gibbs sampler was used to estimate variance components. The EBV were obtained using all animals included in the pedigree or bulls with at least 10 daughters with stayability observations, and average genetic trends were obtained in the liability and transformed to the probability scale. Additional analyses were performed to study the genetic relationship among stayability traits, which were compared by contrasting results in terms of EBV and the average genetic superiority as a function of the selected proportion of sires. Heritability estimates and SD were 0.25 +/- 0.02, 0.22 +/- 0.03, and 0.28 +/- 0.03 for Stay5, Stay6, and Stay7, respectively. Average genetic trends, by year, were 0.51 +/- 0.34, and 0.38% for Stay5, Stay6, and Stay7, respectively. Estimates of EBV SD, in the probability scale, for all animals included in the pedigree and for bulls with at least 10 daughters with stayability observations were 7.98 and 12.95, 6.93 and 11.38, and 8.24 and 14.30% for Stay5, Stay6, and Stay7, respectively. A reduction in the average genetic superiorities in Stay7 would be expected if the selection were based on Stay5 or Stay6. Nonetheless, the reduction in EPD, depending on selection intensity, is on average 0.74 and 1.55%, respectively. Regressions of the sires' EBV for Stay5 and Stay6 on the sires' EBV for Stay7 confirmed these results. The heritability and genetic trend estimates for all stayability traits indicate that it is possible to improve fertility with selection based on a threshold analysis of stayability. The SD of EBV for stayability traits show that there is adequate genetic variability among animals to justify inclusion of stayability as a selection criterion. The potential linear relationship among stayability traits indicates that selection for improved female traits would be more effective by having predictions on the Stay5 trait.
Resumo:
The experiment was conducted to evaluate pigeon pea (Cajanus cajan) protein in broiler chicks (up to 28 days of age) feeding, as compared to soybean (Glycine mar) protein, In the experiment the effects of temperature and autoclaving on antinutritional factors on pigeon pea meal were studied. Temperatures of 100, 110 e 120 degrees C and times of autoclaving of 10, 20 and 30 minutes were applied using a two-way factorial design, replicated in four times. Underheating and overheating during the process of inactivation of proteases inhibiting were evaluated by ureatic activity and protein solubility analysis, after the grains were dried and ground. After 28 days, the best time of autoclaving was 20 minutes (p<,05) irrespectively of temperature, which lead to a lower feed consuption. There were no histopathological alterations in kidney, liver, pancreas, heart and intestines of the broilers.
Resumo:
A pressure analgesiometric device was developed for unrestrained cats. Eleven cats were studied. Stimulation was via three rounded pins within a bracelet on the forearm. The pins were advanced by manual bladder inflation. Bladder pressure was measured using a strain gauge pressure transducer. The threshold was recorded at the behavioural end point. Thresholds were measured at 5 and 15 min intervals for 2-4 h, after removal/replacement of the cuff, for 120 min after SC butorphanol (0.4 mg/kg), and with mild skin inflammation at the testing site. Data were analysed using ANOVA. Pressure thresholds in untreated cats were around 150 mmHg. The minimum interval for testing was established as 15 min. Data were reproducible over 4 h and beyond 24 h. Thresholds in 5 cats increased (P < 0.05) above baseline for 45 min after butorphanol with a maximum increase of 270 +/- 182 mmHg at 10 min. Thresholds decreased with inflammation. The method appears suitable for feline analgesia investigations. (c) 2006 Elsevier Ltd. All rights reserved.
Resumo:
New compound isolated from methanolic extract from the leaves of Paepalanthus argenteus var. argenteus (Bongard) Hensold was characterized as xeractinol, a new dihydroflavonol C-glucoside. The structure was elucidated on the basis of extensive spectroscopic analysis (1D and 2D NMR, MS, HREIMS, IR and UV). Ab initio electronic structure calculations support our proposal to the molecular structure. The dihydroflavonol herein isolated may serve as taxonomic marker of Paepalanthus subgenus Xeractis, because this flavonoid have not been reported in any other taxon of Eriocaulaceae.
Resumo:
Litter production was measured for two years (november 1986 to october 1988) in a 29 year -old Pinus elliottii var. elliottii stand in differents resin treatments. Needle production comprised 9 to 93% of total litter fall, while the other categories (branches, barks, seeds and cones) were not significant. Maximum litterfall occurred in march to may 1987 (autumn) and the minimum was in august 1988 (winter) for all treatments and the control. No relationship appeared between annual litterfall and environmental factors, although there was a tendence to exhibit two periods of production: one in summer and other in winter. The results showed that in two years of resin extraction was not sufficient in interfering the litter fall and consequently the productivity.
Resumo:
Annual and monthly quantities of nutrients wich returned to the soil through litter fall in Pinus elliottii Engelm. var. elliottii stand were estimated durint a two years period, in Experimental Station of Mogi-Guacu, SP. From the trees of the stand was extracted oleoresin according two differents techniques and control. The annual average of nutrients that returned to the soil was 72.2 Kg/ha, in following order: N > Ca > K > Mg > P. No relationship appeared between nutrient concentrations plus quantities when they were compared with oleoresin yields treatments and control. The differences in annual quantities were possibly due to climatic factors. The soil profile showed short concentrations in nutrient contents. Thus, the forest may be suffering by nutrient deficiences.
Resumo:
Rhizopus microsporus var. rhizopodiformis produced high levels of alpha-amylase and glucoamylase under solid state fermentation, with several agricultural residues, such as wheat bran, cassava flour, sugar cane bagasse, rice straw, corncob and crushed corncob as carbon sources. These materials were humidified with distilled water, tap water, or saline solutions-Segato Rizzatti (SR), Khanna or Vogel. The best substrate for amylase production was wheat bran with SR saline solution (1:2 v/v). Amylolytic activity was still improved (14.3%) with a mixture of wheat bran, corncob, starch and SR saline solution (1:1:0.3:4.6 w/w/w/v). The optimized culture conditions were initial pH 5, at 45 degrees C during 6 days and relative humidity around 76%. The crude extract exhibited temperature and pH optima around 65 degrees C and 4-5, respectively. Amylase activity was fully stable for 1 h at temperatures up to 75 degrees C, and at pH values between 2.5 and 7.5.
Resumo:
Farmers are interested in producing popcorn under organic production systems and propane flaming could be a significant component of an integrated weed management program. The objective of this study was to collect baseline information on popcorn tolerance to broadcast flaming as influenced by propane dose and crop growth stage at the time of flaming. Field experiments were conducted at the Haskell Agricultural Laboratory of the University of Nebraska, Concord, NE in 2008 and 2009 using five propane doses (0, 13, 24, 44 and 85 kg ha(-1)) applied at the 2-leaf, 5-leaf and 7-leaf growth stages. Propane was applied using a custom-built research flamer driven at a constant speed of 6.4 km h(-1). Crop response to propane dose was described by log-logistic models on the basis of visual estimates of crop injury, yield components (plants m(-2), ears plant(-1), kernels cob(-1) and 100-kernel weight) and grain yield. Popcorn response to flaming was influenced by the crop growth stage and propane dose. Based on various parameters evaluated, popcorn flamed at the 5-leaf showed the highest tolerance while the 2-leaf was the most susceptible stage. The maximum yield reductions were 45%, 9% and 16% for the 2-leaf, 5-leaf and 7-leaf stages, respectively. In addition, propane doses that resulted in a 5% yield loss were 23 kg ha(-1) for the 2-leaf and 7-leaf and 30 kg ha(-1) for the 5-leaf stage. Flaming has a potential to be used effectively in organic popcorn production if properly used. (C) 2010 Elsevier Ltd. All rights reserved.