208 resultados para Somaclonal and Androclonal variation


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The reproductive system of male Phrynops geoffroanus adults is macroscopically described and the variation in testicular biometry is evaluated. A pair of oval testes is connected by the efferent ductules to the epididymis, which continue as deferent ducts, which emerge in the penis. The volume of the gonads showed the highest averages during spring and summer months. GSI varied significantly throughout the year, with the highest averages observed in the months that correspond to the end of spring and the beginning of summer, when the reproduction of the species takes place, and the lowest averages were seen in winter, suggesting a cyclical testicular activity.

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Mössbauer spectroscopy was used to investigate the early aging stage of iron(III) hydroxide sols prepared by oxidation of Fe(CO)5 in ethanolic solution, followed by vacuum drying at room temperature. One sample was composed of amorphous particles, while two other samples were partially crystallized, either as a result of solvent change or of spontaneous aging. The main results of Mössbauer measurements in the 80-320 K temperature range are: (a) partially crystallized particles exhibit a strong, S-shaped temperature dependence of the quadrupole splitting, in contrast to a weak and linear variation for amorphous particles; (b) the recoilless fraction temperature dependence is affected by vibration of the particles as a whole, with an effective force constant which is smaller for crystallized particles than for amorphous ones. Furthermore, the former exhibit anf-factor discontinuity near 0°C, which is attributed to melting of a surface layer built up during the crystallization process. © 1986.

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Power-law distributions, i.e. Levy flights have been observed in various economical, biological, and physical systems in high-frequency regime. These distributions can be successfully explained via gradually truncated Levy flight (GTLF). In general, these systems converge to a Gaussian distribution in the low-frequency regime. In the present work, we develop a model for the physical basis for the cut-off length in GTLF and its variation with respect to the time interval between successive observations. We observe that GTLF automatically approach a Gaussian distribution in the low-frequency regime. We applied the present method to analyze time series in some physical and financial systems. The agreement between the experimental results and theoretical curves is excellent. The present method can be applied to analyze time series in a variety of fields, which in turn provide a basis for the development of further microscopic models for the system. © 2000 Elsevier Science B.V. All rights reserved.

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The mechanism of formation and growth of hydrous iron oxide (FeOOH) during the initial stages of forced hydrolyses of ferric chloride aqueous solution was studied by small angle X-ray scattering (SAXS). The effect of the hydrolysis temperature (60°C, 70°C and 80°C) and of the addition of urea on the formation of colloidal particles under isothermal conditions were investigated. Based on the experimental scattering functions in the Guinier range, we suggest the presence of elongated colloidal particles. The particle diameter and length, and their variation with time, were determined by fitting the form factor of prolate ellipsoids to the experimental scattering functions. We have assumed that our solutions are in a dilute state and that all colloidal particles are approximately of the same size. The colloidal particles have geometrical shapes similar to those of the subcrystals that build up the superstructure of β-FeOOH crystals, indicating that the formation of this hydrous iron oxide is governed by an aggregation process. Otherwise, the addition of urea hinders the growth and yields smaller particles, with a reduction in size greater than 50%. © 2000 Elsevier Science B.V. All rights reserved.

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Ammonia is the most common alkaline gas of the atmosphere, being important in the neutralization of various processes that occur in the atmosphere. Its main sources of emission are the decomposition of organic matter and dejections of animals. Ammonia is used by man in diverse activities of production, therefore it is a gas that can contaminate work environments. Measurements of ammonia concentration in some parts of the world have shown great spatial and weather variation. This large variability makes it difficult to estimate the input of reduced nitrogen to different ecosystems from measurements.

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The objective of this work is to analyze the effects of salinity and wastewater on the zooplankton community of the Itanhaém river estuary, São Paulo state. Samples of zooplankton as well as physical and chemical variables of water were collected in four sites, located between the coastal line and the superior part of the estuary, including a secondary channel where wastewater is thrown without previous treatment. The samples were collected in low and high tide in winter and summer. Results showed that the estuary presents a temporal and spatial variation of physical and chemical characteristics, especially salinity, in function of the tide and seasonal variation of rain. The high values of salinity occurred in winter and high tide. Zooplankton community was adapted to the dynamic of salinity, and marine and estuarine species occurred in the low part of the estuary in winter. Although the Itanhaém river estuary has the same temporal and spatial dynamic of other estuaries, the values of salinity are low when compared with others located in the southern coast of São Paulo. Consequently, mainly oligohaline and fresh water species constitute the zooplankton community. These characteristics are due to the great drainage area of the Itanhaém river basin. The waste water modified physical and chemical characteristics of water that now presents higher concentrations of nutrients, higher values of suspended matter and lower concentrations of oxygen. It was observed a positive relation between the density of nauplii of copepods and organic pollution in this estuary.

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The assessment of welfare issues has been a challenge for poultry producers, and lately welfare standards needs to be reached in order to agree with international market demand. This research proposes the use of continuous behavior monitoring in order to contribute for assessing welfare. A software was developed using the language Clarium. The software managed the recording of data as well as the data searching in the database Firebird. Both software and the observational methodology were tested in a trial conducted inside an environmental chamber, using three genetics of broiler breeders. Behavioral pattern was recorded and correlated to ambient thermal and aerial variation. Monitoring video cameras were placed on the roof facing the used for registering the bird's behavior. From video camera images were recorded during the total period when the ambient was bright, and for analyzing the video images a sample of 15min observation in the morning and 15 min in the afternoon was used, adding up to 30 min daily observation. A specific model so-called behavior was developed inside the software for counting specific behavior and its frequency of occurrence, as well as its duration. Electronic identification was recorded for 24h period. Behavioral video recording images was related to the data recorded using electronic identification.. Statistical analysis of data allowed to identify behavioral differences related to the change in thermal environment, and ultimately indicating thermal stress and departure from welfare conditions.

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The ant Paratrechina longicornis is a cosmopolitan ant species that has been accidentally spread by commerce around the world, and now is a pest of houses and hospitals. The morphology of its larval stages has been previously described without knowledge of the number of instars. The present study revisits the original description of P. longicornis larvae by adding differences observed among the three larval instars. Compared to other Paratrechina species studied so far, P. longicornis presents smaller larvae, less evident variation in mandible morphology, and clear variation in the morphology of head hairs between the analysed specimens of the second and third instar larvae. Ultrastructural images of the eggs, larval spiracle ornamentation, and pupae are also presented for the first time. Copyright © 2007 - Magnolia Press.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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The present study aimed at analyzing and comparing longitudinally the EMG (electromyographic activity) of the superior orbicularis oris muscle according to the breathing mode. The sample, 38 adolescents with Angle Class II Division 1 malocclusion with predominantly nose (PNB) or mouth (PMB) breathing, was evaluated at two different periods, with a two-year interval between them. For that purpose, a 16-channel electromyography machine was employed, which was properly calibrated in a PC equipped with an analogue-digital converter, with utilization of surface, passive and bipolar electrodes. The RMS data (root mean square) were collected at rest and in 12 movements and normalized according to time and amplitude, by the peak value of EMG, in order to allow comparisons between subjects and between periods. Comparison of the muscle function of PNB and PMB subjects at period 1 (P1), period 2 (P2) and the variation between periods (Δ) did not reveal statistically significant differences between groups (p < 0.05). However, longitudinal evaluation of the muscle function in PNB and PMB subjects demonstrated different evolutions in the percentage of required EMG for accomplishment of the movements investigated. It was possible to conclude that there are differences in the percentage of electric activity of the upper lip with the growth of the subjects according to the breathing mode.

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We describe a new species of Helicops from the southern Amazon Basin in the state of Mato Grosso, Brazil. It differs from all congeners by having dorsal scales in 21/21/19 rows in males and 23/21/19 rows in females, subcaudal keels, a banded dorsal color pattern, and 14-19 ventral blotches. Besides presenting information on the lepidosis and morphometric variation, we also describe the hemipenis and discuss the known distribution of the new species. © 2013 by The Herpetologists' League, Inc.

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A bounded upwinding scheme for numerical solution of hyperbolic conservation laws and Navier-Stokes equations is presented. The scheme is based on convection boundedness criterion and total variation diminishing stability criteria and developed by employing continuously differentiable functions. The accuracy of the scheme is verified by assessing the error and observed convergence rate on 1-D benchmark test cases. A comparative study between the new scheme and conventional total variation diminishing/convection boundedness criterion-based upwind schemes to solve standard nonlinear hyperbolic conservation laws is also accomplished. The scheme is then examined in the simulation of Newtonian and non-Newtonian fluid flows of increasing complexity; a satisfactory agreement has been observed in terms of the overall behavior. Finally, the scheme is used to study the hydrodynamics of a gas-solid flow in a bubbling fluidized bed. © 2013 John Wiley & Sons, Ltd.

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Pós-graduação em Alimentos e Nutrição - FCFAR

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)