1000 resultados para Estrutura de repouso
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In northeastern Brazil, Octopus insularis is the most commercially important cephalopod species and its capture has been performed for several years by the lobster fishermen in the region. In order to obtain information about the reproductive biology, 1108 specimens were collected between November 2009 and September 2011 in the landings and fish markets of Rio do Fogo (RN). For each specimen the mantle length (CM) and total fresh weight (PT) were recorded. Gonads of 264 males and 295 females were examined macroscopically and histologically to assess sexual maturation and determine reproductive indices. Four reproductive stages were determined for males (immature, maturing, mature and post-mature) and females (immature, early maturing, late maturing and mature). The average of eggs recorded in the female s gonads was 93.820 and 39 was the average of spermatophores found in male Needham s complex. Spermathecae with sperm were found in females with 69 mm CM (immature). Males and females become sexually mature at 64.41 and 98.50 mm of CM, respectively. The weight at sexual maturity was 270 g for males and 630 g for females. The values of the size and weight at sexual maturity found in this study show that males mature at smaller sizes than females. For both sexes the maturation peaks occurred in February and November 2010 and also in September 2011. The periods of maximum reproductive activity lasted about 3 months and it seems to occur every 7 10 months. Only one spent female (stage V) was found and the number of mature females was low. Presumably, mature females migrate to deep waters with complex habitat to protect the offspring, indicating that fishery by snorkeling with maximum depth of 15 meters is not reaches this part of the stock. Finally, it is noticeable the importance of the establishment of management strategies for the exploitation of O. insularis different of the ones used for O. vulgaris, once the species have distinct biological features
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The Brazilian Northeast is the most vulnerable region to climatic variability risks. For the Brazilian semi-arid is expected a reduction in the overall rates of precipitation and an increase in the number of dry days. These changes predicted by the IPCC (2007) will intensify the rainfall and droughts period that could promote the dominance of cyanobacteria, thus affecting the water quality of reservoirs, that are most used for water supply, in the semi-arid. The aim of this study was to evaluate the effects of increasing temperature combined with nutrient enrichment on the functional structure of the phytoplankton community of a mesotrophic reservoir in the semi-arid, in the worst case scenario of climate change predicted by the IPCC (2007). Two experiments were performed, one in a rainy season and another in the dry season. In the water sampled, nutrients (nitrate and orthophosphate) were added in different concentrations. The microcosms were submitted to two different temperatures, five-year average of air temperature in the reservoir (control) and 4°C above the control temperature (warming). The results of this study showed that warming and nutrient enrichment benefited mainly the functional groups of cyanobacteria. During the rainy season it was verified the increasing biomass of small functional groups of unicellular and opportunists algae such as F (colonial green algae with mucilage) and X1 (nanoplanktonic algae of eutrophic lake systems). It was also observed an increasing in total biomass, in the richness and diversity of the community. In the dry season experiment there was a greater contribution in the relative biomass of filamentous algae, with a replacement of the group S1 (non-filamentous cyanobacteria with heterocytes) for H1 (filamentous cyanobacteria with heterocytes) in nutrient- enriched treatments. Moreover, there was also loss in total biomass, species richness and diversity of the community. The effects of temperature and nutrients manipulation on phytoplankton community of reservoir Ministro João Alves provoked changes in species richness, the diversity of the community and its functional composition, being the dry period which showed the highest susceptibility to the increase in the contribution of potentially toxic cyanobacteria with heterocytes
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The inherent complexity of natural communities is a challenge to our understanding about how the habitat influences the abundance, local distribution and species diversity. The habitat can influence community structure in multiple ways and elucidate these relationships has provoked a lot of debate in ecology. The habitat heterogeneity hypothesis states that an increase in habitat heterogeneity (number of habitats) leads to an increase in species diversity in the landscape due to an expansion in niche dimensions. This study aims to identify whether this hypothesis is valid for the spiders that inhabit a locality in the Caatinga of northeastern Brazil. Cursorial and arboreal spiders were sampled in 30 plots within an area of Caatinga together with measures of environmental complexity, habitat heterogeneity and environmental parameters related to multiple aspects of vegetation architecture and species composition of woody plants. Stepwise multiple regressions were used to define which local environmental parameters best explain the variation in arboreal and cursorial spiders richness. Then a NMDS (Nonmetric multidimensional scaling) was used to reduce the number of predictive variables to those who are the most important and best represent the variation in spiders richness associated with the environment they were sampled. The results show a clear segregation between the guilds of arboreal and cursorial spiders, both related to what kind of environmental variables best explain its variation as well as in relation to what part of the vegetation they occupy
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The economic transformations in the world, the end of World War II, listing significant changes in production structures and labor market in the world. Initially developed countries realize these changes and subsequently developing countries. The changes in production patterns, especially with the crisis of Fordism, peripheral countries further accentuated the problems in the workplace. Flexible accumulation, in turn, was responsible for significant changes in the labor market at the periphery of global capitalism. This restructuring process, in Brazil, begun from the end of the 1980s and early 1990s, being more accentuated the impacts on the labor market in the poorest regions of the country, particularly the Northeast. In that sense, this thesis aims to evaluate the job market in the metropolitan areas of Fortaleza, Recife and Salvador in light of the transformation process in the production structures and labor market and its influences in the 2000s. The time frame are the years 2001-2008. Data are from the National Household Sample Survey - PNAD and were drawn from the study proposal developed by the Centre of the Metropolis. The study shows that the labor market of the three metropolitan areas continues to be affected by the restructuring process of the late twentieth century. It found high rates of unprotected busy at work is more precarious conditions of employment for non-whites, women, adolescents / young and old. We also highlight the high percentage of employed persons earning income up 1.00 minimum wage, and a large number of persons employed in the tertiary and tertiary non-specialist. With the picture observed in the three metropolitan areas you can see the major problems in the labor market that proliferate, especially in the metropolitan context of the Northeast, with characteristics similar to those observed in the literature that investigated the labor market in 1990
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This study aims to analyze the income differentials by gender in Brazil, in the years 1976, 1987, 1996 and 2009. Specifically, there are two objectives. First, attempt to analyze the importance of the effects of composition and wage structure in the job market. In the second, to verify which socioeconomic variables explain the effects of composition and wage structure in the job market. The information in this study was obtained from the microdata of Pesquisa Nacional por Amostra de Domicílios (PNAD) regarding the respective years. In the first stage of the methodology we used: the index of income distribution Theil-T; the income gap decompositions proposed by Oaxaca (1973) and Blinder (1973); and Firpo et al. (2007). In the second stage we applied the RIF regression method (Recentered Influence Function) of Firpo et al. (2007). The results show that income inequality is higher among men than among women in the country. It was observed that the component of inequality between people of the same gender represented the largest share in the decomposition of income inequality between genders. It was found, in the decomposition of the average income, a downward trend of income gap, but the differential remains favorable to the men. We noticed that the impact of the composition effect in reducing the gap was offset by the positive effect of wage structure. Regarding the distribution quantis, income differential between genres appeared greater at the bottom, in the years 1976, 1987 and 2009; and at the top of the distribution, in 1996 featuring, respectively, the sticky floor and glass ceiling effects in Brazil. As for the decomposition of the RIF, it turns out that the composition effect assisted in the downfall of the income gap between 1976 and 2009, but was offset by the positive effect of the wage structure in quantis 10th, 50th, and 90th. The main socioeconomic variables influenced the drop in income gap were: the composition effect, the manual labor occupations, service sector and low-grade and high school, and the wage structure effect, schooling low and high experience professional and technical occupations and urban centers
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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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This study aimed to assess the effect of harvesting times and of post-harvest resting period on physical characteristics of fruits and seeds of castor bean (AL Guarany 2002 genotype) and to verify if theses characteristics could be used to identify the ideal harvest time. Nine times of raceme harvest were assessed from 30 to the 142 days after anthesis (DAA) at fourteen days intervals, and four conditions of resting; (without and with seven days of resting period of seeds extracted (bare), from fruits and fixed to the racemes). It was evaluated water content, seed thickness, and length, width, and weight of fresh fruits and seeds, and seedling emergence in sand. The statistical design was completely randomized with four replications. The harvest times and the post-harvest rest period affected the physical characteristics of fruits and seeds of castor bean but none of these have proved to be effective in the identification of the ideal harvest time.
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Foram estudados os efeitos da glutamina, dos ácidos graxos poli-insaturados e da parede celular de levedura (PCL) sobre a estrutura e ultraestrutura do intestino delgado e o desempenho de leitões. Foram utilizados 45 leitões, desmamados aos 21 dias de idade, para testar os seguintes tratamentos: T1 - dieta basal; T2 - dieta basal + 1% de glutamina; T3 - dieta basal + 0,2% de PCL; T4 - dieta basal + 5% de óleo de peixe. Nos dias sete e 14 pós-desmame, foram abatidos cinco leitões de cada tratamento. Os aditivos testados não alteraram a altura e a densidade dos vilos nem a profundidade das criptas do intestino delgado. Foi observado efeito de idade, mostrando redução na altura e na densidade dos vilos e na profundidade das criptas após o desmame. No duodeno e jejuno, foram observados maiores valores de relação vilo:cripta, que aumentaram com a idade pós-desmame. Ocorreram redução da altura dos microvilos do duodeno aos sete dias e aumento da largura dos microvilos do jejuno aos 14 dias pós-desmame. A área de superfície apical dos enterócitos não foi alterada pelos fatores estudados. Os aditivos estudados não foram eficientes em prevenir a atrofia da mucosa intestinal do jejuno, ao não interferir na sua ultraestrutura. Os aditivos incluídos na dieta não influenciaram o desempenho dos leitões no pós-desmame.
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In this thesis, it is developed the robustness and stability analysis of a variable structure model reference adaptive controller considering the presence of disturbances and unmodeled dynamics. The controller is applied to uncertain, monovariable, linear time-invariant plants with relative degree one, and its development is based on the indirect adaptive control. In the direct approach, well known in the literature, the switching laws are designed for the controller parameters. In the indirect one, they are designed for the plant parameters and, thus, the selection of the relays upper bounds becomes more intuitive, whereas they are related to physical parameters, which present uncertainties that can be known easier, such as resistances, capacitances, inertia moments and friction coefficients. Two versions for the controller algorithm with the stability analysis are presented. The global asymptotic stability with respect to a compact set is guaranteed for both cases. Simulation results under adverse operation conditions in order to verify the theoretical results and to show the performance and robustness of the proposed controller are showed. Moreover, for practical purposes, some simplifications on the original algorithm are developed
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The automatic speech recognition by machine has been the target of researchers in the past five decades. In this period have been numerous advances, such as in the field of recognition of isolated words (commands), which has very high rates of recognition, currently. However, we are still far from developing a system that could have a performance similar to the human being (automatic continuous speech recognition). One of the great challenges of searches for continuous speech recognition is the large amount of pattern. The modern languages such as English, French, Spanish and Portuguese have approximately 500,000 words or patterns to be identified. The purpose of this study is to use smaller units than the word such as phonemes, syllables and difones units as the basis for the speech recognition, aiming to recognize any words without necessarily using them. The main goal is to reduce the restriction imposed by the excessive amount of patterns. In order to validate this proposal, the system was tested in the isolated word recognition in dependent-case. The phonemes characteristics of the Brazil s Portuguese language were used to developed the hierarchy decision system. These decisions are made through the use of neural networks SVM (Support Vector Machines). The main speech features used were obtained from the Wavelet Packet Transform. The descriptors MFCC (Mel-Frequency Cepstral Coefficient) are also used in this work. It was concluded that the method proposed in this work, showed good results in the steps of recognition of vowels, consonants (syllables) and words when compared with other existing methods in literature
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In this work, the variable structure adaptive pole placement controller (VS-APPC) robustness and performance are evaluated and this algorithm is applied in a motor control system. The controller robustness evaluation will be done through simulations, where will be introduced in the system the following adversities: time delay, actuator response boundeds, disturbances, parametric variation and unmodeled dynamics. The VS-APPC will be compared with PI control, pole placement control (PPC) and adaptive pole placement controller (APPC). The VS-APPC will be simulated to track a step and a sine reference. It will be applied in a three-phase induction motor control system to track a sine signal in the stator reference frame. Simulation and experimental results will prove the efficiency and robustness of this control strategy
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The advent of the Internet stimulated the appearance of several services. An example is the communication ones present in the users day-by-day. Services as chat and e-mail reach an increasing number of users. This fact is turning the Net a powerful communication medium. The following work explores the use of communication conventional services into the Net infrastructure. We introduce the concept of communication social protocols applied to a shared virtual environment. We argue that communication tools have to be adapted to the Internet potentialities. To do that, we approach some theories of the Communication area and its applicability in a virtual environment context. We define multi-agent architecture to support the offer of these services, as well as, a software and hardware platform to support the accomplishment of experiments using Mixed Reality. Finally, we present the obtained results, experiments and products
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Este estudo foi realizado com o objetivo de avaliar o efeito da forma física da ração sobre o desempenho, a utilização dos nutrientes das rações e o desenvolvimento do trato disgestório de pintos de corte na primeira semana de vida. Foram utilizados 150 pintos machos Cobb distribuídos ao acaso em três tratamentos com cinco repetições de dez aves. Os tratamentos consistiram das formas físicas farelada, triturada e peletizada de uma ração pré-inicial comercial. Com exceção da moela, os órgãos do trato digestório e a estrutura morfométrica do intestino não foram influenciados pela forma física da ração. Maior digestibilidade do N foi obtida com a ração peletizada, enquanto a ração triturada possibilitou maior digestibilidade do EE. A energia metabolizável determinada para a ração farelada foi menor que a obtida nas demais formas físicas da ração. As aves alimentadas com ração farelada tiveram menor consumo de ração e ganho de peso e pior conversão alimentar. Ingeriram ainda menos energia, apresentaram menores retenções de proteína, gordura e energia corporal e utilizaram maior proporção da energia ingerida para produção de calor. As rações pré-iniciais na forma peletizada ou triturada possibilitam maior aproveitamento dos nutrientes da ração pelos pintos e melhor desempenho.
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In this Thesis, the development of the dynamic model of multirotor unmanned aerial vehicle with vertical takeoff and landing characteristics, considering input nonlinearities and a full state robust backstepping controller are presented. The dynamic model is expressed using the Newton-Euler laws, aiming to obtain a better mathematical representation of the mechanical system for system analysis and control design, not only when it is hovering, but also when it is taking-off, or landing, or flying to perform a task. The input nonlinearities are the deadzone and saturation, where the gravitational effect and the inherent physical constrains of the rotors are related and addressed. The experimental multirotor aerial vehicle is equipped with an inertial measurement unit and a sonar sensor, which appropriately provides measurements of attitude and altitude. A real-time attitude estimation scheme based on the extended Kalman filter using quaternions was developed. Then, for robustness analysis, sensors were modeled as the ideal value with addition of an unknown bias and unknown white noise. The bounded robust attitude/altitude controller were derived based on globally uniformly practically asymptotically stable for real systems, that remains globally uniformly asymptotically stable if and only if their solutions are globally uniformly bounded, dealing with convergence and stability into a ball of the state space with non-null radius, under some assumptions. The Lyapunov analysis technique was used to prove the stability of the closed-loop system, compute bounds on control gains and guaranteeing desired bounds on attitude dynamics tracking errors in the presence of measurement disturbances. The controller laws were tested in numerical simulations and in an experimental hexarotor, developed at the UFRN Robotics Laboratory