1000 resultados para relative commutant


Relevância:

20.00% 20.00%

Publicador:

Resumo:

Arenaeus cribrarius is a mainly tropical crab that occurs in the Western Atlantic Ocean, Brazil being its type-locality. The species ranges from Vinevard Sound, Massachusetts, USA to La Paloma, Uruguay. Information about this species is scarce. The relative growth of A. cribrarius was analyzed, based on some morphometric relations, where the carapace width, excluding lateral spines (CW), was used as an independent variable. A total of 403 specimens (189 males and 214 females), was collected in Ubatuba, State of São Paulo, Brazil, with otter-trawls. The animals were sexed and sorted to maturation phase (juvenile or adult). Some measurements were made: carapace (length and width excluding lateral spines), abdomen (greatest width of the fifth somite in females and the sixth in males) and major chela (greatest length, width and height, dactylus length). This study was made by the application of the power function (y=a.x(b)) which was fitted to the data and the pattern of growth established for each parameter by the ''b''-value (constant of allometry), as positive allometry (b>1), negative allometry (b<1) or isometry (b=1). The morphometric relations of the carapace showed a tendency to isometry. In females, the abdominal width grew in positive allometry, higher in juveniles (b=1.33) than in adults (b=1.18). In this case, an overlap and discontinuity was noticed between the phases over a carapace width range of 55 to 70 mm, where the puberty molt occurs. The majority of relationships showed that the major chela of the males grew in positive allometry, however, the greatest allometric difference between the phases was observed towards the propodus length with 1.09 as juvenile and 1.26 as adult ''b''values. In the males, this variable showed an inflection between the CW range of 45' to 55 mm, where the transition to the maturation phase occurs. The relative growth of this species is similar to those of previously studied species. This indicates, that the propodus length and the abdominal width are the morphometric variables most appropriate to estimate the size of the beginning of the sexual maturity for males and females of this species, respectively.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The dimensions of chelar propodus and abdomen were utilized for the morphometric analysis about the relative growth studies of Acanthonyx scutiformis (Dana, 1851). A total of 297 specimens (114 males and 183 females), was collected in Ubatuba, State of São Paulo, Brazil. The animals were sexed and soarted to maturation phase (immature and mature). The following measurements were made: carapace (length and width), abdomen width and chelar propodus (length and height). In this study was applicated the power function (y= a.x(b)), in which the growth was considered positive allometric with isometric with b=1, and negative allometric with b<1. The alometry becomes isometric, when the results concerning immature and mature females and males are analysed. In the Brachyura male chelipeds are utilized in territorial defense, fight, display and courtship and female abdomens are utilized as a chamber that protect and incubate the eggs.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This study was conducted to assess the effects of incubation temperature (34 C, 36[degree]C and 38[degree]C) and relative humidity (RH, 50% and 60%) on egg weight loss, embryo mortality, hatchability, incubation time and chick weight in eggs from red-winged tinamou. The eggs were placed in incubators that were operated at 34[degree]C, 36[degree]C, or 38[degree]C and 50% or 60% RH (mean wet bulb temperatures of 28[degree]C and 30[degree]C, respectively) from day 1 to hatching. Each treatment had two replicate groups of 30 eggs each. Hatchability varied with incubation temperature and RH and was highest for eggs incubated at 36[degree]C and 60% RH and lowest for eggs incubated at 38[degree]C. Early, intermediate and late embryo mortality were highest at 38[degree]C, 38[degree]C/50% RH, and 50% RH, respectively. Incubation period was longest at 34[degree]C and shortest at 38[degree]C/50% RH. Present results show the highest hatchability of red-winged tinamou eggs after incubation at 36[degree]C and 60% RH; highest embryo sensitivity to high temperature in the early period of incubation (1 to 7 days), to high temperature and low RH in the second period of incubation (8-14 days) and to low RH in the late period of incubation (after 15 days) and shortest incubation period with increasing temperature and RH.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Based on behaviour of output growth and industrial sector prices, it tries to define the several stages comprising the cyclic trends of the Brazilian economy. Analyzes the behaviour of inflation rates and of relative prices, and shows that there is a positive association between the measures of inflation rates and of their variables as well as between both these measures and dispersion of relative price changes. Demonstrates the assymetric behaviour of relative price changes and differentiated behaviour in relative prices of farm produce and industrial products. -from Authors

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Adjusted mean catches which are calculated discounting the effect of average fishing effort increase the further the lake is from Manaus, Brazil. -from Author

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Patterns of attack for collected species of phorids are predicted using multivariate morphometrics of female Pseudacteon species and worker size distributions of parasitized fire ants, Solenopsis saevissima. The model assumes that there is a direct correlation between phorid size and the size range of the worker ant attacked, and presumes that worker sizes are a resource that is divided by sympatric phorid species to minimize joint parasitism. These results suggest that the community of sympatric Pseudacteon species on only one host species coexists by restricting the size of workers attacked, and secondarily by differing diel patterns of ovipositional activity. When we compared relative abundance of species of Pseudacteon with the size distribution of foragers of S. saevissima, our observed distribution did not differ significantly from our predicted relative abundance of females of Pseudacteon. The activity of Pseudacteon may be a factor determining forager size distributions.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The purpose of this paper is to characterize the lability/inertness metal fractions complexed by aquatic humic substances (HS) in relation to pH, complexation time, and HS concentration. HS were preconcentrated by ultrafiltration and complexed with bivalent metal ions. These fractions were characterized by ion exchange with the chelating collector cellulose Hyphan by applying batch procedure. The metals were determined by atomic absorption spectrometry. The results show that the distribution coefficients, Kd, decreased with HS presence, and that the relative lability of metal fractions complexed by HS is dependent on variables such as pH, complexation time, and HS concentration. Until c.a. 15 min, the metal change between aquatic HS and ion exchanger occurs following a 2 order reaction. Afterwards, the remaining metal fraction in the HS reacts following a 1st order reaction. For traces of metal ions bound to dissolved HS, the lability orderPb > Mn > Cd, Ni > Cu is revealed. ©1997 Soc. Bras. Química.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Cucurbits species grown in 38 of 40 agricultural regions in the state of Sao Paulo, Brazil, were surveyed for the relative incidence of Cucumber mosaic virus (CMV), Papaya ringspot virus-type W (PRSV-W), Watermelon mosaic virus-2 (WMV-2), Zucchini lethal chlorosis virus (ZLCV), and Zucchini yellow mosaic virus (ZYMV) during May 1997 and June 1999. Samples from 621 plants, representing eight cultivated species, six wild species, and one commercial hybrid (Cucurbita moschata x C. maxima), were analyzed by plate trapped antigen enzyme-linked immunosorbent assay (PTA-ELISA). PRSV-W and ZYMV were the most frequently found viruses, accounting for 49.1 and 24.8%, respectively, of 605 samples tested. ZLCV, CMV, and WMV-2 were detected in 7.8, 6.0, and 4.5% of 612, 497, and 423 samples tested, respectively. Double infection was found in 97 samples, and triple infection was found in 10 samples. Quadruple infection was detected in one C. pepo sample. Plants that were symptomatic but negative by PTA-ELISA might be due to abiotic agents, infection by virus for which antiserum was not available, such as Squash mosaic virus, or infection with an as yet uncharacterized virus.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Cobb male broiler chicks (1,000) on new litter were used to evaluate effects of dietary electrolyte balance [DEB; Na+K-Cl, milliequivalents (mEq) per kilogram] under tropical summer conditions. Corn-soybean meal-based mash diets had salt (NaCl) alone or in combination with one or more supplements: sodium bicarbonate (NaHCO3), ammonium chloride (NH4Cl), or potassium bicarbonate (KHCO3). A completely randomized design, with five starter and grower feed treatments (control: 145, then 130 mEq/kg; or 0, 120, 240, or 360 mEq/kg throughout) and four replicate pens (1.5 x 3.2 m) per treatment (50 chicks per pen), was used. Diets were analyzed for Na, K, and Cl for confirmation. There were no significant (P < 0.05) effects of treatments on mortality or processing parameters. Water intake increased linearly with increasing DEB, giving higher litter moistures and lower rectal temperatures. Blood HCO3 and pH increased with the highest DEB (360 mEq/kg) causing respiratory alkalosis. The DEB of 240 mEg/kg gave best weight gain and feed conversion ratio, and ideal DEB predicted by regression analyses were 186 and 197 mEq/kg from 0 to 21 d of age and 236 and 207 mEq/kg of feed from 0 to 42 d, respectively. These DEB corresponded to estimated (interpolated) values in predicted optimal 186 to 197 mEq/kg starter of Na 0.38 to 0.40% and Cl 0.405 to 0.39% (K = 0.52%), in 207 to 236 mEq/kg starter, Na 0.409 to 0.445% and Cl 0.326 to 0.372% Cl (K = 0.52%), and in grower Na 0.41 to 0.445%, Cl 0.315 to 0.267% (K = 0.47%).

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Systematic errors can have a significant effect on GPS observable. In medium and long baselines the major systematic error source are the ionosphere and troposphere refraction and the GPS satellites orbit errors. But, in short baselines, the multipath is more relevant. These errors degrade the accuracy of the positioning accomplished by GPS. So, this is a critical problem for high precision GPS positioning applications. Recently, a method has been suggested to mitigate these errors: the semiparametric model and the penalised least squares technique. It uses a natural cubic spline to model the errors as a function which varies smoothly in time. The systematic errors functions, ambiguities and station coordinates, are estimated simultaneously. As a result, the ambiguities and the station coordinates are estimated with better reliability and accuracy than the conventional least square method.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

A 90-day feeding experiment was conducted with sex reversed Nile tilapia (Oreochromis niloticus) fingerlings fed purified or practical diets supplemented with different zinc sources to evaluate fish growth performance and zinc and iron retention in fish bones, fillets, liver, skin and eyes. The relative bioavailability value (RBV) of zinc in the supplemental sources tested was also calculated. Fish were fed with isonitrogenous and isoenergetic purified or practical diets supplemented with 150 mg Zn kg -1, as zinc sulphate monohydrate (ZnSO 4), zinc oxide (ZnO) or zinc amino acid complex (Zn-AA). The feeding trial was conducted in 30, 50 L aquaria where four 0.66 ± 0.01 g (mean ± SD) fingerlings were initially stocked. No significant differences were observed for any growth performance variables (P > 0.05). In practical diets, only ZnSO 4 and ZnO presented bone zinc retention similar to that for the standard zinc source. Zinc concentration in the bone of fish fed practical diet supplemented with Zn-AA (171 ± 3.62 μg g -1) was significantly lower than that verified for the practical diets supplemented with the standard zinc source (200 ± 17.7 μg g -1) or with ZnSO 4 (204 ± 19.9 μg g -1). Assuming the concentration of zinc in bones as the response criterion, the supplemental zinc RBV from ZnSO 4 (105%) was higher than the RBV for Zn-AA (95.1%) or ZnO (94.9%). Iron concentration in the bones of animals fed the non-zinc-supplemented purified diet was significantly higher than that observed for purified diet supplemented with Zn-AA (P < 0,05). The results of the present work allowed us to conclude that ZnSO 4 in relation to ZnO or Zn-AA was the supplemental zinc source with higher zinc bioavailability to Nile tilapia. © 2005 Blackwell Publishing Ltd.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Ten isonitrogenous casein-gelatin-based diets were formulated to contain five estimated metabolizable energy concentrations (10.92, 12.29, 13.63, 14.82 and 16.16 kJ g -1) at two carbohydrate-to-lipid ratios (CHO : L, 5.3 and 12.8, g : g) in a 5 × 2 factorial arrangement. Each diet was assigned to triplicate groups of 11 piracanjuba fingerlings (5.25 ± 0.14 g) and fed to apparent satiation twice a day for 90 days. Higher daily weight gain was obtained by fish fed the 13.63 kJ g -1 diets for both CHO : L ratios. There was a significant reduction of feed consumption when dietary energy concentration increased above 13.63 kJ g -1. Feed conversion ratio and apparent net energy retention improved as dietary energy increased. Apparent net protein retention tended to be lower in the highest and lowest dietary energy concentrations. The results suggest that dietary lipid energy was more efficiently utilized by piracanjuba fingerlings than carbohydrate energy. Body composition and hepatosomatic index (HSI) were not influenced by dietary CHO : L ratio. However, an increase in dietary energy concentration beyond 13.63 kJ g -1 resulted in a significant increment in lipid deposition, while body moisture and HSI decreased. Our findings indicate that at 300 g kg -1 dietary crude protein, a CHO : L ratio of 5.3 is recommended for piracanjuba, and the required energy is either 13.63 kJ g -1 if raised for aquaculture or 14.82 kJ g -1 if destined to stock enhancement. © 2006 Blackwell Publishing Ltd.