946 resultados para relative growth rate (RGR)
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The Santana Cave is located at the Upper Ribeira Touristic State Park (PETAR-Parque Estadual Turistico do Alto Ribeira) in southern São Paulo State, Brazil. This paper describes Pb-210 activity concentration data in soda straw stalactites samples collected at Salao das Flores in Santana Cave that is a fossil tributary of the cave river. Non-expensive alpha counting following some analytical steps for extracting and depositing Pb-210 were used for providing the Pb-210 data. In the analyzed samples, Pb-210 values of increasingly older samples fitted an exponential curve, thus suggesting that the production of Pb-210 has been constant with time. Also, the near-ideal fit indicated that the growth was uniform and there was no break in the continuous growth. The soda straw growth rates were determined from the best fit to the exponential curve through the Pb-210 activity concentration. The results of the measurements allowed estimate a longitudinal rate corresponding to 1.3 mm/yr and a lateral rate of 0.01 mm/yr, which permitted calculate times of 70 years and 317-498 years for their formation, respectively. The lateral growth rate is compatible with values from studies of chemical weathering rates held under laboratory and natural conditions. (C) 2011 Elsevier Ltd. All rights reserved.
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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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Os efeitos de prostaglandina (PGF2a) vs CIDR e eCG (gonadotrofina coriônica eqüina) na dinâmica folicular da primeira onda e sua relação com as concentrações plasmáticas de P4 e E2 foram investigadas em ovelhas cíclicas. Foram utilizadas 14 fêmeas ovinas da raça Bergamascia; o Grupo 1 (G1) foi submetido a duas aplicações de PGF2alfa e o Grupo 2 (G2), tratado com CIDR durante 14 dias, sendo que, no momento de sua retirada, administraram-se 500 UI de eCG. A dinâmica folicular ovariana foi monitorada por meio de ultra-som. Monitoraram-se todos os folículos > 2mm e mapeou-se sua posição diariamente, observando-se o desenvolvimento individual de cada folículo. Desde o dia anterior à aplicação da segunda dose de PGF2alfa (G1) e desde a administração de eCG (G2) até o décimo dia do ciclo estral, foram coletadas amostras de sangue para análise de P4 e E2. Houve diferença significativa nas concentrações plasmáticas de P4 e E2 entre os tratamentos. A sincronização de estro e ovulação, utilizando CIDR + 500 UI de eCG, incrementou a quantidade de folículos recrutados, além de aumentar o diâmetro máximo e a taxa de crescimento dos folículos grandes na primeira onda folicular.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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The relative growth of U. thayeri was studied for a subtropical mangrove population in the estuary of the Comprido and Escuro rivers, Ubatuba, São Paulo State, Brazil. The evaluation of the morphological sexual maturity of U. thayeri was performed using the allometric technique. Remarkable ontogenetic changes were observed in the allometric growth of the male major cheliped and the female abdomen, indicating that these structures are closely connected to the timing of sexual maturity. For males, the relative-growth analysis of cheliped propodus length rendered an estimate of 13.8 mm of carapace width for the size at onset of sexual maturity. A distinct growth pattern was observed for the abdomen of U. thayeri females. It has a wide puberty size range (from 10.7 to 16.8 mm of CW) compared to other brachyurans previously studied. Thus, the females' abdominal growth can be represented by three growth phases: immature, transitional, and mature. The major cheliped is the fight one in 50% of males. The median length of the male major cheliped did not differ between right- and left-handed crabs.
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A total of 1,800 incubating eggs produced by a commercial flock of Cobb broiler breeders was used to determine the effects of storage duration (3 or 18 d) on spread of hatch and chick quality. Chick relative growth (RG) at the end of 7 d of rearing was also determined as a measure of the chick performance. Chick quality was defined to encompass several qualitative characteristics and scored according to their importance. Eggs stored for 3 d hatched earlier than those stored for 18 d (P < 0.05). Hatching was normally distributed in both categories of eggs, and the spread of hatch was not affected by storage time (P = 0.69). Storage duration of 18 d reduced the percentage of day-old chick with high quality as well as average chick quality score (P < 0.05). RG varied with length of egg storage, quality of day-old chick, and the incubation duration (P < 0.05). Eighteen-day storage of eggs not only resulted in longer incubation duration and lower quality score but also depressed RG. Chick quality as defined in this study was correlated to RG and storage time. It was concluded that day-old chick quality may be a relatively good indicator of broiler performance. The results suggest however that in order to improve performance prediction power of chick quality, it would be better to define it as a combination of several qualitative aspects of the day-old chick and the juvenile growth to 7 d.
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Volume changes of the vitellarium components of the leaf-cutting ant Atta sexdens rubropilosa are reported. The oocyte grew to approximately 409 times of its initial volume and reached a maximum value of 1.2 x 10(7) mu m(3). The follicle increase in size at a more or less constant rate up to the 12(th), showing an elevated growth rate thereafter. The mean number of follicles per ovariole was 16.42 +/- 3.58.
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A per capita model for the growth, development and reproduction of the coccinellid predator Rhizobius lophanthae (Blaisd) feeding on the oleander scale (Aspidiotus nerii Bouche (Homoptera: Diaspididae)) was developed. A thermal threshold for development of 9.4 degrees C was found. Under conditions of unlimited food, the relationship of mass at time t+1 to that at t (in days at 25 degrees C) suggests an 8.7 percent growth rate per mg larvae per day at 25 degrees C. An adult female beetle produces approximately 20 eggs per day while consuming an average of 8.5 scales/day. This is approximately 2.16 eggs per scale consumed above the maintenance level of 1.88 scales per day. More precisely, this compensation point is 0.12 mg of prey/mg of predator/day at 25 degrees C and the egestion rate is 1 - beta = 0.63.
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Follicle diameter deviation is defined as the beginning of the differential change in growth rates between the largest and next largest follicles subsequent to wave emergence and is considered a key component of follicle selection. Follicle selection has been extensively studied in European breeds of cattle (Bos taurus) but has not been critically studied in Zebu breeds (Bos indicus). The objectives of the present study were to determine and compare the morphological characteristics of deviation associated with the first post-ovulatory wave (Wave 1) of the estrous cycle in Nelore heifers (n = 8) and nonlactating cows (n = 11). Beginning on the day of ovulation (day 0), the three largest follicles (F1-F3, respectively) were individually tracked every 12 h for 6 d using transrectal ultrasonography. In individual animals, deviation was determined graphically using visual inspection of the diameter profiles of F1, F2 and sometimes F3 (observed deviation) and mathematically using segmented regression analysis of the diameter differences between F1 and F2 or sometimes F3 (calculated deviation). Mean day of emergence of Wave 1 when F1 reached >3 rum (approximately 1 d after ovulation) and growth rate of F1 during deviation (approximately 1.4 mm/d) were not significantly different between heifers and cows. The results of determining the beginning of deviation within heifers and cows using the observed and calculated methods were not significantly different. Averaged over both methods, diameter deviation occurred 2.8 d after ovulation when F1 reached 5.7 mm in heifers, and 2.4 d after ovulation when F1 reached 6.1 mm in cows. In conclusion, the emergence of Wave 1 and growth rates and diameters of the future dominant follicles at the beginning of deviation were similar in Nelore heifers and nonlactating cows, regardless of the methods used to determine deviation. Relative to Holstein cattle, emergence of Wave 1 appeared to occur about 1 d later and diameter of the future dominant follicle at the beginning of deviation was about 2 turn smaller in Nelore. (C) 2004 Elsevier B.V. All rights reserved.
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We study the growth dynamics of the size of manufacturing firms considering competition and normal distribution of competency. We start with the fact that all components of the system struggle with each other for growth as happened in real competitive business world. The detailed quantitative agreement of the theory with empirical results of firms growth based on a large economic database spanning over 20 years is good with a single set of the parameters for all the curves. Further, the empirical data of the variation of the standard deviation of the growth rate with the size of the firm are in accordance with the present theory rather than a simple power law. (C) 2003 Elsevier B.V. B.V. All rights reserved.
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Colour preference of individual juvenile rainbow trout Oncorhynchus mykiss was tested at 1 and 12 degrees C, and also at 12 degrees C after a 42 day growth experiment under white, blue, green, yellow or red ambient colour. All experiments were carried out under controlled laboratory conditions and the preference was assessed by the location of the fish in a preference tank with four chambers. Rainbow trout showed a preference for blue and green at 1 degrees C and for green at 12 degrees C. After the growth experiment the fish reared in blue tanks preferred blue and green but green was the most preferred colour for the fish reared in green, yellow and red tanks. Yellow and especially red chambers were avoided, irrespective of the ambient colour during the growth trial. The final mass of fish reared in the red aquaria was significantly smaller than that of the fish in green tanks. In addition, when the data of the preference tests were correlated with the data of the growth experiment using mean values of the four tested colours, a very good linear relationship was observed between the preference (i.e. visit frequency in coloured compartments) and growth rate as well as food intake. When considering the results both from the preference and growth trials it is suggested that green is the best environmental colour for rearing juvenile rainbow trout while rearing in a red environment cannot be recommended. (c) 2008 The Authors Journal compilation (c) 2008 The Fisheries Society of the British Isles.
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Los efectos de la prostaglandina (PGF2α) vs CIDR y eCG (gonadotrofina coriónica equina) en la dinámica de la población folicular y su relación con las concentraciones plasmáticas de P4 fueron investigadas en ovejas cíclicas. Fueron utilizadas 14 hembras ovinas de la raza Bergamascia; el Grupo 1 (Gl) se sometió a dos aplicaciones de PGF2α, y, el Grupo 2 (G2) tratado con CIDR durante 14 días siendo que, en el momento de su retirada, se administraron 500 UI de eCG. La dinámica folicular ovárica fue monitoreada por medio de ecógrafo. Se monitorearon todos los folículos ≥ mm y se gráfico su posición diariamente, observándose el desarrollo individual folicular. Desde el día anterior a la aplicación de la segunda dosis de PGF2α, (Gl) y desde la administración de eCG (G2) hasta el décimo día del ciclo estral se colectaron muestras de sangre para el análisis de P4. Hubo diferencia significativa (P<0,001) en las concentraciones plasmáticas de P4 entre los tratamientos. La sincronización del estro y ovulación utilizando CIDR + 500 UI de eCG, incrementó la cantidad de folículos reclutados, además de aumentar el diámetro máximo y la tasa de crecimiento de los folículos grandes en la primera onda folicular. En consideración a los resultados se puede concluir que la sincronización del estro y de la ovulación en hembras ovinas, utilizando el CIDR y 500 UI de eCG, incrementa la cantidad de folículos reclutados, además de aumentar el diámetro máximo y la tasa de crecimiento de los folículos grandes. La asociación CIDR+500 UI de eCG provoca aumentos significativos en las concentraciones plasmáticas de progesterona (P4) al inicio de la fase luteal en hembras ovinas.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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We tested the effects of monochromatic light on the specific growth rate (SGR), feed intake and feed efficiency (FE) of juvenile pikeperch, Sander lucioperca (L.). Pikeperch were reared individually for 42 days in aquaria covered with blue, green, yellow or red gelatin filters or white paper (control; n=5). Linear regression analysis indicated a significant positive effect of longer wavelengths of light on the condition factor (CF), FE and SGR. The final weight, SGR and CF were significantly higher in fish reared under red than under white light, and FE was better under green, yellow and red light than under white light (Dunnett's post hoc test, P < 0.05) while blue was comparable to white light in terms of the measured parameters. After the growth trial, the spectral sensitivity of photoreceptor cells in the retina was tested using microspectrophotometry, which revealed the presence of rods with lambda(max) at ca. 530 nm and two cone classes, absorbing maximally at ca. 535 and 603 nm, all containing a porphyropsin-based pigment. These results suggest that the presence of mid and long wavelength-sensitive cones enhances visual sensitivity under mid-wavelength and long-wavelength environments, and thus supports the finding that longer wavelengths of incoming light can improve FE and SGR of the cultivated pikeperch.