1000 resultados para Grupos de simetria
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O presente trabalho foi conduzido com o objetivo de avaliar as características morfológicas e físicas da planta e do fruto de jabuticabeiras, pertencentes à coleção da FCAV-UNESP, Câmpus de Jaboticabal-SP. A coleção conta com 160 plantas, das quais 40, que apresentavam frutificação no momento da seleção, foram agrupadas, preliminarmente, segundo características semelhantes, em quatro grupos denominados JAB 01, JAB 02, JAB 03 e JAB 04. Mediram-se nestes grupos a altura da planta, diâmetro do tronco a 20 cm do solo, diâmetro de copa, comprimento do entrenó e largura da folha. Os frutos, foram avaliados quanto a comprimento, largura, massa fresca da casca, da semente, da polpa e total, bem como o número de sementes por fruto. O delineamento utilizado foi o inteiramente casualisado, com 4 tratamentos, quatro grupos de plantas e 5 repetições, com 2 plantas por repetição. Os dados foram submetidos à análise de variância pelo teste (F) e as médias comparadas pelo teste de Tukey. Observou-se grande variabilidade nos grupos estudados. O JAB-04 revelou-se como o mais promissor para utilização em programas de melhoramento, pela precocidade de produção, baixo porte e maior rendimento em polpa, apesar de os frutos apresentarem menor tamanho em relação aos dos demais grupos.
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O objetivo deste estudo foi investigar, por meio de dados simulados, o efeito da heterogeneidade de variância residual entre grupos de contemporâneos (GC) sobre as avaliações genéticas de bovinos de corte, e comparar o uso de uma avaliação genética ponderada (R¹Isigmae²) em relação à avaliação que pressupõe homogeneidade de variância (R=Isigmae²). A característica estudada foi ganho de peso pós-desmame corrigido para 345 dias, sendo esta simulada com variância fenotípica de 300 kg² e herdabilidade igual a 0,4. A estrutura de um conjunto real de dados foi utilizada para fornecer os GC e os pais referentes às observações de cada animal. Cinco níveis de heterogeneidade de variância residual foram considerados de forma que os componentes de variância fossem, na média, iguais aos da situação de homogeneidade de variância. Na medida em que níveis mais acentuados de heterogeneidade de variância residual foram considerados, os animais foram selecionados dos GC com maior variabilidade, especialmente com pressão de seleção intensa. em relação à consistência de predição, os produtos e as vacas tiveram seus valores genéticos preditos mais afetados pela heterogeneidade de variância residual do que os touros. O fator de ponderação utilizado reduziu, mas não eliminou o efeito da heterogeneidade de variância. As avaliações genéticas ponderadas apresentaram resultados iguais ou superiores àqueles obtidos pelas avaliações que assumiram homogeneidade de variância. Mesmo quando não necessário, o uso de avaliações ponderadas produziu resultados não inferiores às avaliações que assumiram homogeneidade de variância.
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In the past 50 years, large efforts have been made toward the understanding of the stellar evolution. In the observational context, large sets of precise measurements of projected rotational velocity were produced, in particular by the Natal and Geneva groups. From these data, it is now possible to establish the behavior of stellar rotation from the turnoff to the red giant branch. In addition, these data have shown the role of tidal effects on stellar rotation in close binary systems. Nevertheless, relatively little attention has been paid to theoretical studies on the evolution of rotation along the HR Diagram, a topic itself directly associated to the evolution of the stars. Basically, there are two reasons for such a fact, (i) spherical symmetry is not assumed, what leads to a substantial increase in the numerical complexity of equations and (ii) non rotating models have been very successful in explaining relevant observational data, including the mass-luminosity relation and chemical abundances. In spite of these facts, it is clear that considerable work remains to be done on the role of rotation in the later stages of the evolution, where clear disagreements arise from confrontations between theoretical predictions and observations. In the present work we study the evolutionary behavior of stellar rotation along the HR Diagram, taking into account constraint conditions issued from recent observational survey of rotational velocity carried out with high precision procedures and new evolutionary codes
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
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Conselho Nacional de Desenvolvimento Científico e Tecnológico
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BACKGROUND: Treadmill training with partial body weight support (BWS) has shown many benefits for patients after a stroke. But their findings are not well known when combined with biofeedback. OBJETIVE: The purpose of this study was to evaluate the immediate effects of biofeedback, visual and auditory, combined with treadmill training with BWS on on walking functions of hemiplegic subjects. METHODS: We conducted a clinical trial, randomized controlled trial with 30 subjects in the chronic stage of stroke, underwent treadmill training with BWS (control), combined with visual biofeedback, given by the monitor of the treadmill through the symbolic appearance of feet as the subject gave the step; or auditory biofeedback, using a metronome with a frequency of 115% of the cadence of the individual. The subjects were evaluated by kinematics, and the data obtained by the Motion Analysis System Qualisys. To assess differences between groups and within each group after training was applied to ANOVA 3 x 2 repeated measures. RESULTS: There were no statistical differences between groups in any variable spatio-temporal and angular motion, but within each group there was an increase in walking speed and stride length after the training. The group of visual biofeedback increased the stance period and reduced the swing period and reason of symmetry, and the group auditory biofeedback reduced the double stance period. The range of motion of the knee and ankle and the plantar flexion increased in the visual biofeedback group. CONCLUSION: There are no differences between the immediate effects of gait training on a treadmill with BWS performed with and without visual or auditory biofeedback. However, the visual biofeedback can promote changes in a larger number of variables spatiotemporal and angular gait
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Objective: To compare the effects of the treadmill training with partial body-weight support (TPBWS) and Proprioceptive Neuromuscular Facilitation (PNF) method on gait of subjects with chronic stroke. Design: Quasi-experimental study. Setting: Laboratorial research. Participants: Twenty-three subjects (13 men and 10 women), with a mean age of 56,7 ± 8,0 years and a mean time since the onset of the stroke of 27,7 ± 20,3 months, and able to walk with personal assistance or assistive devices. Interventions: Two experimental groups underwent gait training based on PNF method (PNF group, n=11) or using the TPBWS - Gait Trainer System 2, Biodex, USA (TPBWS group, n=12), for three weekly sessions, during four weeks. Measures: Evaluation of motor function - using the Stroke Rehabilitation Assessment of Movement (STREAM) and the motor subscale of the Functional Independence Measure (motor FIM) -, and kinematic gait analyze with the Qualisys System (Qualisys Medical AB, Gothenburg, Sweden) were carried out before and after the interventions. Results: Increases in the STREAM scores (F=49.189, P<0.001) and in motor FIM scores (F=7.093, P=0.016), as well as improvement in symmetry ratio (F=7.729, P=0.012) were observed for both groups. Speed, stride length and double-support time showed no change after training. Differences between groups were observed only for the maximum ankle dorsiflexion over the swing phase (F=6.046, P=0.024), which showed an increase for the PNF group. Other angular parameters remain unchanged. Conclusion: Improvement in motor function and in gait symmetry was observed for both groups, suggesting similarity of interventions. The cost-effectiveness of each treatment should be considered for your choice
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Cytogenetic studies have been revealing a great diversity not detected, until then, in several families of fishes. Many of these groups, especially those that exhibit great diversity, like Perciformes and Siluriformes, possess species with difficult morphologic characterization, called cryptic species, commonly detected through karyotypic analyses, which reveals outstanding interespecific variations with relationship to the number and its chromosomal structures. Thus, the present work intends to contribute for the cytogenetic knowledge of marine and brackish fish species, because they peculiar life habits and by lack of cytogenetic data of your genetic aspects. Therefore, cytogenetic studies were developed in a species of Apogonidae (Perciformes), two species of sea catfishes of the family Ariidae (Siluriformes) and brackish fish Paurachenipterus galeatus (Siluriformes, Auchenipteridae), through C banding, Ag-NOR, use of base-specific flourochromes (DAPI and CMA3), as well as FISH (Fluorescent in situ hybridization) using ribosomal DNA probes 5S and 18S. The present results contribute to a better understanding of the processes of differentiation patterns and chromosome evolution in these groups. The use of other approaches (the morphology and molecular tools) will allow a larger understanding of the genetic and biological diversity of the Brazilian ichthyofauna.
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Lemon sharks, Negaprion brevirostris, are common in the Fernando de Noronha Archipelago, but detailed information about the species in this site is lacking. The aim of this study was to describe the spatial distribution, grouping behavior, habitat use and behavioral ecology of juvenile lemon sharks in the archipelago, and their interaction with some environmental and ecological factors. During 2006 and 2007, the presence and spatial distribution of juvenile sharks were quantified through scuba diving and snorkeling at several sites of the archipelago. In 2008 the habitat use of juvenile sharks was quantified through visual census while snorkeling along 300 x 8 m strip transects. During these transects the grouping behavior of lemon sharks was quantified by ad libitum. Results indicate that Fernando de Noronha Archipelago is used as a nursery area for lemon sharks, and the parturition occurs from November to April. Juveniles preferred using shallower areas available by the tide variation and formed groups only in the presence of adult conspecifics. This preference for shallower habitats and the group behavior probably are anti-predatory tactics used by juvenile lemon sharks, in response to the low availability of shelter and high predation risk of the studied areas. Quantifications of prey availability and predation risk of juveniles showed that, in general, lemon sharks are trading-off food by security and investing in sites with higher possibility of energetic return. Behavioral observations enabled to record juvenile carangid fishes following juvenile lemon sharks, remora host-parasite and juvenile sharks foraging on schools of herrings and octopuses. We also recorded the behavior of juvenile sharks following conspecifics of similar size, circling with two or three individuals and smaller individuals giving way to larger juveniles. When adults are present, juvenile lemon sharks are more social than solitary, indicating that predation is one of the factors that contribute to social behaviors of the species. Results also suggest that when grouped the juveniles have a hierarchical organization according to body size. Furthermore, observation of large adult females with several fresh mating bites and scars in the same habitats used by juvenile lemon sharks, indicates that Fernando de Noronha Archipelago is used as nursery and mating grounds by this species
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The juvenile period represents the developmental phase between weaning and sexual maturity. Weaning occurs when the youngster does not receive direct care from the caretakers anymore. Individuals in the species Callithrix jacchus live in groups composed by the reproductive pair and successive twin sets. Cooperative care is the rule. Infants are weaned early, and from then on, food is provided by the adults in the group. These animals present high levels of social interactions, through play, grooming and social contact. During infant age, the twin becomes the main partner. There are few studies about the juvenile period, especially on Callithrix gender. The objective of this study was describing the pattern of activities and social interactions of four sets (one single and three twin sets) during juvenile phase in two Callithrix jacchus groups. We used instantaneous and continuous focal sampling for juveniles and scan sampling for adults behavioral recordings. Juveniles presented the same behavioral pattern as the adults relating the activity budget, in particular, foraging along the months. The composition of the diet was the same as that of the adults. Food transfer ended along the juvenile period. Social play as much as grooming were important socializing activities for the juveniles. The young individuals in the group were the main partners in social play, specially the twin. Adults were the main partners in grooming interactions. Scent marking differed between twins in the male/female sets, the female presenting the highest levels of marking. The juveniles were independent from adults in foraging activity. Social interaction varied according to group composition, but in general, interacted more with the twin and with the youngsters (infants and subadults), except in grooming. Even presenting many similarities, juveniles showed some differences between genders, which indicates the differentiation in behavior towards reproductive strategies early in the juvenile period
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The Callitrichidae family is characterized by flexibility in its mating system, being possible to find monogamous, polyandrid and polygynic groups. Its social organization and mating system can be defined by the interaction between ecological and demographic factors plus the degree of relatedness among the individuals in the population. The objective of this work was to demonstrate the influence of relatedness and coexistence on the establishment and maintenance of social relations between Callithrix jacchus adult males. Four pairs of related adult males (CP), 4 pairs with coexistence between the animals in the pair (CC) and 4 pairs with no relatedness (SP) were studied. The pairs in the group CC had been kept in the same cage for at least 8 months before the experiment and the pairs in the group SP were put together at the beginning of the study. Each animal was observed 3 times/week for 2 months, in 15 min. sessions, through focal time sampling with instantaneous record each minute. In the first month, only the pair of males was kept in the cage (Phase I) and in the second month, a female was introduced into the cage (Phase II). The affiliative, agonistic and sexual interactions were registered. Affiliative interactions showed similar frequencies for all groups in phases. There was also no significant difference in the agonistic interactions of the CP, CC and SP males in Pase I, even considering that group SP exhibited higher levels of agonism. In Phase II, there was a statistically significant increase comparing to the others. The results demonstrate that relatedness and coexistence are of great importance for maintaining reprodutive and social stability inside the group. Nonetheless, in this study, only one of the males in the pair had sexual interations with the females, except for 2 pairs. This was assured through mate guarding and agonism directed to the potencial competitor. The most probable mating system would be functional monogamy, where the males would present low levels of competition, if there is relatedness and coexistence among them; on the other hand, a strong competition if there is no relatedness between the individuals. Even so, a polyandric system would also have to be considered
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The Callitrichidae family presents cooperative breeding, where breeders and non breeders take care of the offspring. The aspects of care analyzed in this study were infant carrying, supervision, proximity and food transfer. Three sets of infants from two wild groups of Callithrix jacchus were studied in the environments of Caatinga (Assu group) and Atlantic Forest (Jundiaí group). The methods used in the study were instantaneous focal sampling (infant carrying, supervision and proximity) and continuous focal sampling (food transfer). In the two sets observed in Assu group, the father carried and transferred food to infants more than the rest of the group. The biggest contribution in supervision was from the father and from another adult male. The members that remained in proximity to the infants in both groups were the younger in the groups (juveniles and sub-adults). In the Jundiaí group, the father and the adult male helper of the group were the main caregivers; one of the sub-adult females was responsible for supervision of the infants. With the disappearance of the reproductive male and one of the sub-adults females in 3º month of infants life, the care was redistributed and the only adult male left in the group was the animal that contributed more in provisioning of the infant. In the Assu group, there were adult females in its composition which were involved in agonistic interactions with breeders and adult males, and seemed to influence their low participation in care. Food transfer initiates early in the development of the infants, as a way to encourage nutritional independence. Different types of food transfer (active food transfer, food steal, food steal attempt, passive food transfer and food handling) were observed in the study and frequency of each one varied with developmental phase and tolerance by the members. One relevant data of the study was the presence of active food transfer in Assu group, since in literature there are very few registers of this type of transfer for this species. It is important that groups from distinct environments and composition be studied for a better understanding of the dynamics of infants development
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Latexes based on acrylic acid, acrylamide, ethyl methacrylate, and ethyl acrylate were synthesized via emulsion polymerization with different monomer compositions. The resultant latices were thickened with different molar ratios of NaOH to acrylic acid and were analyzed in terms of acid‐basis titrimetry, turbidimetry, rheology, and tensiometry. Titrimetry, turbidimetry, and rheometry were used to analyze factors such as carboxyl group availability and particle solubilization, tensiometry monitoring the influence of carboxyl neutralization on polymer‐surfactant interactions. For the acrylic acid content used in this work (20 wt%), the results indicated that as carboxyl groups distribution became more homogeneous, the process of latex thickening became more effective
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Data clustering is applied to various fields such as data mining, image processing and pattern recognition technique. Clustering algorithms splits a data set into clusters such that elements within the same cluster have a high degree of similarity, while elements belonging to different clusters have a high degree of dissimilarity. The Fuzzy C-Means Algorithm (FCM) is a fuzzy clustering algorithm most used and discussed in the literature. The performance of the FCM is strongly affected by the selection of the initial centers of the clusters. Therefore, the choice of a good set of initial cluster centers is very important for the performance of the algorithm. However, in FCM, the choice of initial centers is made randomly, making it difficult to find a good set. This paper proposes three new methods to obtain initial cluster centers, deterministically, the FCM algorithm, and can also be used in variants of the FCM. In this work these initialization methods were applied in variant ckMeans.With the proposed methods, we intend to obtain a set of initial centers which are close to the real cluster centers. With these new approaches startup if you want to reduce the number of iterations to converge these algorithms and processing time without affecting the quality of the cluster or even improve the quality in some cases. Accordingly, cluster validation indices were used to measure the quality of the clusters obtained by the modified FCM and ckMeans algorithms with the proposed initialization methods when applied to various data sets