Peer effects on locus of control

Eu analiso o papel que a interação entre pares tem na determinação do Locus de Controle, uma medida de quão pessoalmente responsável as pessoas se sentem com relação a diferentes aspectos de suas vidas. Eu estabeleço identificação através de variação no tamanho do grupo e de variáveis instrumentais baseadas na estrutura de painel dos dados. Eu estudo a questão no contexto escolar, utilizando os dados de alunos no Ensino Fundamental de um município brasileiro, que inclui o questionário de Tel Aviv de Locus de Controle. Minhas estimativas não apresentam sinais de peer effects endógenos ou contextuais.

Seasonal changes in fecal testosterone concentrations and their relationship to the reproductive behavior, antler cycle and grouping patterns in free-ranging male Pampas deer (Ozotoceros bezoarticus bezoarticus)

The purpose of this study was to validate noninvasive endocrine monitoring techniques for Pampas deer and to evaluate seasonal changes in testicular steroidogenic activity and their correlation to reproductive behavior, antler cycle and group size. Thus, fecal samples, behavioral data and observations of antler status were collected at monthly intervals during 1 year from free-ranging Pampas deer stags (three radio-collared individuals and 15 random individuals) living in Emas National Park, Brazil (18 degrees S latitude). Fecal steroids were extracted using 80% methanol and steroid concentrations were quantified by a commercial enzyme immunoassay (EIA). Fecal testosterone concentrations peaked in December-January (summer), March (early autumn) and in August-September (winter-spring), with minimal values from April-July. Reproductive behavior had two peaks, the first in December-January, characterized by predominately anogenital sniffing, flehmen, urine sniffing, chasing and mounting behavior, and the second peak in July-September (behavior primarily related to gland marking). There were significant correlations between fecal testosterone and reproductive behavior (r = 0.490), and between fecal testosterone and antler phases (r = 0.239). Antler casting and regrowth occurred under low testosterone concentrations, whereas velvet shedding was associated with high concentrations of testosterone. We inferred that Pampas deer stags exhibited a seasonal cycle that modulated sexual behavior and the antler cycle, and we concluded that fecal steroid analysis was a practical and reliable non-invasive method for the evaluation of the endocrine status of free-ranging Pampas deer. (c) 2004 Elsevier B.V. All rights reserved.

Ecologia alimentar do boto cinza, sotalia guianensis (van banédén, 1864), no litoral do rio grande do norte (rn)

This study investigated factors that influence the group size during the behavior foraging of estuarine dolphin Sotalia guianensis in the coast south of the state Rio Grande do Norte (RN), it also characterized the diet of estuarine dolphins and elaborated an otoliths catalog for aid in the identification of the preys found in the stomach contents. In relation to the group size during behaviour foraging, inside of the Curral Bay, larger frequency of solitary hunt was observed. Factors as tide variation, group composition and seasons didn't present correlation with the number of animals observed during a feeding episode. Capture success for participant was shown significantly larger when the animals hunted alone, what possibly explains the largest frequency of solitary hunt inside of the Curral Bay. About diet, were identified 18 bone fishes species, with predominance of species the families Haemulidae and Sciaenidae and five cephalopods species, including two new species in the diet of Sotalia guianensis in Brazil. Our results indicated that estuarine dolphin in the coast oriental from Rio Grande do Norte (RN) feeds predominantly of fish that form shoal, of habitat estuarino and producing of sounds. The analysis of the images, otoliths of 43 species of coastal fish of the coast of the state of Rio Grande do Norte (RN), aided by the offered descriptions, demonstrated to be an effective methodology for the knowledge of those structures, as well as it represented a form of reducing the subjectivity in the identification of the bone fishes found in stomach content

Boto cinza (Sotalia guianensis, Van Benédén, 1864) (Cetacea, Delphinidae): Atividade aérea, forrageio e interações inter-específicas, na Praia de Pipa (Tibau do Sul RN) e estudo comparativo entre duas populações do Nordeste do Brasil

Sotalia guianensis is a small cetacean of the Delphinidae family, with coastal habits and whose area of distribution ranges from Florianópolis (27º35'S, 48º34'W), in Brazil, to Honduras (15º58'N, 85º42'W). At Pipa beach, on the south coast of RN state, in Brazil, the species occur throughout the year. The present study was carried out in two bays, which are bordered by cliffs. The animals were monitored from vantage points, using the "Ad libitum" and "all the occurrences" methods; during the years of 1999 and 2004. The study was divided in 4 chapters: Behavioral standards of two populations of gray dolphin, (Sotalia guianensis, Van Benédén, 1864) in the northeast of Brazil; Aerial activity of the gray dolphin: its possible function and the influence of environmental and behavioral factors; The influence of daily and monthly variation of the tides, of the period of the day and group size on the gray dolphin forage activity; kleptoparasitism interactions of frigatebird (Fregata magnificens, Mattheus, 1914) during the gray dolphin forage activity. The results have shown that the gray dolphin has a varied and complex behavioral repertoire. The leap is the most frequent behavior; the aerial activity is diffuse during daylight and is influenced by some factors, such as the level of the tide and social factors. The gray dolphin, when in the bay, most frequently feeds isolate or in small groups. The forage is diffuse during daylight; however, being more frequent in the morning and is influenced by the daily and monthly variation of the tide. At Pipa beach, kleptoparasitarian interactions were registered between the gray dolphin and the frigatebird (Fregata magnificens). The frigatebird forage strategy consists basically of two ways: to fly over great extensions searching for dead fish and to steal food (kleptoparasitism). These interactions were predominantly carried out between immature and female adult birds and adult and immature dolphins, and occurred during daylight. The present study can be considered an initial landmark to a better knowledge on the gray dolphin surface behavior, especially regarding the aerial behavioral repertoire and forage strategy of this species. However, it is necessary to continue these studies, so that we can understand better the complex social life of these animals and thus create effective measures for its conservation

Hierarquia social e sucesso alimentar em callithrix jacchus (Primates, Callithrichidae), sob condições naturais

The competition for resources is one of the costs of group living. The scramble competition is considered an indirect type of competition, mainly associated with factors like group size and distribution of resources. Contest competition occurs when individuals compete directly for resources. In species that exibit this type of competition the establishment of dominance hierarchy can occur, resulting in differences on feeding and reproductive benefits for each member of the group. In these cases, aggressive and submissive behaviors are expected as a way to signal social status. The aim of this study was to investigate the effects of social hierarchy over food ingestion in Callithrix jacchus. Data recording was from September/2006 to March/2007, eight days by month, at Floresta Nacional de Açu do Instituto Chico Mendes de Biodiversidade. The observation time started at 05:00 AM and finished after the last animal was on the sleeptree. Analyses of aggressive interactions, behavioral profile and diet, reveals a lot of advantages for dominat animals in the study group. Dominant individuals had higher intake of animal matter that subordinates. The last ones, consumed fruits, exsudate and, eventually, explored itens that were not common to the diet. We suggest that dominance hiearchy enable the reproductive female to assure priority on access to food resources, a important caracteristc to supply tha costs to maintain tha high reproductive taxa of the specie. We also suggest that reproductive male, due to the participation on food transfer, had the forage efficience reduced

Estimativa populacional e uso do hábitat do boto-cinza (Sotalia guianensis) no litoral sul do Rio Grande do Norte

Four areas are known as of frequent usage by Guiana dolphins (Sotalia guianensis) in the south coast of Rio Grande do Norte state, northeast Brazil: Tabatinga, Pipa, Lagoa de Guaraíras and Baia Formosa. This extension of 40 km of shoreline is under increasing anthropogenic impacts due to continuous development of the coastal areas and vessel traffic. The objective of this study was to investigate aspects of population biology and habitat use of the population of Sotalia guianensis in the south coast of Rio Grande do Norte. It was applied the photo-identification technique and posterior methods of capture-recapture for population estimation (POPAN extension in MARK). The distribution, movement and site fidelity of the dolphins were analyzed trough the geographic information system (GIS) and group characteristics and behavior trough non-parametric statistics. Field work was conducted on board a 10m motor vessel from March 2008 to March 2009. Photo-identification effort was 329h with 113h of direct observation of the dolphins. The population estimatives for each area: Tabatinga: 75 (63-92); Pipa 105 (88-129); Lagoa de Guaraíras: 27 (18-54) e Baia Formosa: 112 (89-129) individuals. Total population estimative was: 223 (192 a 297). High site fidelity was detected for only part of the population (<15%) as low site fidelity and transients individuals were also detected (>20%). It was observed frequent movements between Tabatinga, Lagoa de Guaraíras and Pipa, but not Baía Formosa. This suggests a division in two communities along this shore extension: one in Pipa and other in Baía Formosa. Group size was small, most groups with up to 10 dolphins. The areas were use intensively, only in Lagoa de Guaraíras dolphins were not seen in all field trips. Lagoa de Guaraíras is an area used by small groups exclusively for foraging. In Tabatinga and Pipa dolphins concentrated close to the shore, in the inner sector of the area and the main activity is also foraging. Significant larger groups were seen in socializing behavior but there was no difference in group size between the inner and external sectors of the area. The presence of calves and juveniles were significant greater in the inner areas of Tabatinga and Pipa, confirming the hypothesis that these beaches are also used for parental care. In Baia Formosa dolphins concentrated in the outer sector and foraging was also predominant. Significant larger groups were seen in the outer sector, mainly engaged in mixed behaviors of travel/foraging, possibly in some kind of group foraging. Calves and juveniles were significant more present in the outer sector where group size was also larger. In general there was no difference in area usage and period of the day. Sotalia guianensis has characteristics that make the species vulnerable to human activities such as small population concentrated in patches of suitable habitats restrict to coastal areas. We hope that this study bring new information for the species and help for the adequate management of the area in order to assure the presence of the dolphins as well as its behavior pattern and gene flow betweencommunities.

Uso de habitat e comportamento do boto-cinza sotalia guianensis em uma zona estuarina do estado de Sergipe, nordeste do Brasil a biotecnologia vegetal como alternativa para a cotonicu

To clarify the functional mechanisms of habitat use is necessary to analyze it in conjunction with the conduct performed by animals. The occurrence, distribution and use of space are characteristic of a species resulting from habitat selection that is in search of conditions favorable to its survival. One can relate the physical and biological factors of the environment with the ecological characteristics of the species, since these factors act by regulating the ecological success of organisms, and from there you can get important information about the habitat use and behavior of individuals. This study aimed to characterize the use of habitat and diurnal activity expressed by the Guiana dolphin, Sotalia guianensis in an estuarine area of Sergipe state, Brazil, analyzing the influence of tide and time days on the occurrence of animals and behavior s state, and group s size and composition in this cetacean species. From March 2009 to February 2010, focal groups observations of dolphins were made from fixed - point and records snapshots of data taken every 5 min. in the interval from 6 a.m to 6 p.m, in alternating shifts. The results showed that the constant presence of animals in the area of the Sergipe River estuary indicates that this is an important area of occurrence of S. guianensis, which use the region mainly in the morning, at low tide and as a feeding. As in other regions of northeastern Brazil, small groups formed 2-12 individuals were most common, with adults and immatures. The high frequency of immature animals may indicate that this area of the estuary is used as brood area and parental care of pups and young animals, since the immature animals were very associated with adults and monitoring the activities of foraging / feeding may be related to a form of learning or training of such behavior

Efeitos da transformação de uma variável com distribuição normal em sua inversa sobre os parâmetros de sua distribuição usando técnicas de Monte Carlo

Foram realizados quatro estudos de simulação para verificar a distribuição de inversas de variáveis com distribuição normal, em função de diferentes variâncias, médias, pontos de truncamentos e tamanhos amostrais. As variáveis simuladas foram GMD, com distribuição normal, representando o ganho médio diário e DIAS, obtido a partir da inversa de GMD, representando dias para se obter determinado peso. em todos os estudos, foi utilizado o sistema SAS® (1990) para simulação dos dados e para posterior análise dos resultados. As médias amostrais de DIAS foram dependentes dos desvios-padrão utilizados na simulação. As análises de regressão mostraram redução da média e do desvio-padrão de DIAS em função do aumento na média de GMD. A inclusão de um ponto de truncamento entre 10 e 25% do valor da média de GMD reduziu a média de GMD e aumentou a de DIAS, quando o coeficiente de variação de GMD foi superior a 25%. O efeito do tamanho dos grupos nas médias de GMD e DIAS não foi significativo, mas o desvio-padrão e CV amostrais médios de GMD aumentaram com o tamanho do grupo. em virtude da dependência entre a média e o desvio-padrão e da variação observada nos desvios-padrão de DIAS em função do tamanho do grupo, a utilização de DIAS como critério de seleção pode diminuir a acurácia da variação. Portanto, para a substituição de GMD por DIAS, é necessária a utilização de um método de análise robusto o suficiente para a eliminação da heterogeneidade de variância.

The cetacean offal connection: Feces and vomits of spinner dolphins as a food source for reef fishes

At Fernando de Noronha Archipelago, southwest Atlantic, reef fishes associated with spinner dolphins (Stenella longirostris) were recorded when the cetaceans congregated in a shallow inlet. In the reef waters the dolphins engaged in several behaviors such as resting, aerial displays and other social interactions, as well as eliminative behaviors such as defecating and vomiting. Twelve fish species in seven families were recorded feeding on dolphin offal. The black durgon (Melichthys niger) was the most ubiquitous waste-eater, and its group size was positively and significantly correlated with dolphin group size. The durgons recognized the postures a dolphin adopts prior to defecating or vomiting, and began to converge to an individual shortly before it actually voided. Offal was quickly fed upon, and the fishes concentrated in the area occupied by the dolphins until the latter left the shallows. Since all the recorded offal-feeding species feed on plankton or drifting algae, feeding on cetacean droppings may be regarded as a switch from foraging on drifting organisms to foraging on drifting offal, a predictable food source in the inlet. Further instances of this cetacean-fish association are predicted to occur at sites where these mammals congregate over reefs with clear water and plankton-eating fishes.

Vigilance towards raptors by nuclear species in bird mixed flocks in a Brazilian savannah

A nuclear or leader species is the one around which foraging activity is organized. In the campo-cerrado (Brazilian savannah) up to four bird species (Saltator atricollis, Cypsnagra hirundinacea, Mimus saturninus, and Neothraupis fasciata) may function as nuclear or leader species in mixed species flocks. The aim of this study was to assess the features shown by these nuclear species. I quantified parameters of sociality, communication and alertness of nuclear bird species in mixed flocks with different composition. Parameters related to sociality (mean intraspecific group size) and communication (frequency of contact calls) were not correlated with the leadership. on the other hand, the most alert species was in the front of a given mixed flock most of the time. The leader species spent more time in vigilance and gave most alarm calls due to approaching raptors earlier. The results of this study strongly suggest that the alertness of a species is the major character of nuclear bird species in mixed flocks of the campo-cerrado.

Feeding associations between Guiana dolphins, Sotalia guianensis (Van Bénèden, 1864) and seabirds in the Lagamar estuary, Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Guiana dolphins, Sotalia guianensis (Cetacea: Delphinidae), in the Paranaguá Estuarine Complex: insights on the use of area based on the photo-identification technique

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Sentinels in Saltator atricollis (Passeriformes: Emberizidae)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Effects of the density, aviary type, breed, and age on the behaviors of laying hens kept in cages

An experiment was carried out in order to investigate the behaviors of laying hens due to the environmental factors of: density inside of the cage, aviary type, breed, and age. The experiment was configured as a factorial 4x2x2x2 study, with treatments being four different ages, two different breeds, two different cage densities, and two different aviaries. The birds' behaviors were recorded using video cameras installed in the cages, using samples of 15 minutes recorded from 12 PM to 4 PM. The observed behaviors, frequency and duration of behaviors (measured in seconds) were identified and noted related to each bird. The study was initiated in March 2007, during four non-consecutive weeks. The observed behaviors were: opening wings, stretching, threatening, ruffling feathers, drinking water, aggressive pecking, eating, running, lying down, stretching head out of the cage, preening, mounting, prostrating, and doing nothing (inactivity). Due to the non-normality of the data recorded, the Kruskal-Wallis statistical test of the MINITAB Statistical Software® was used to compare the medians of the variables. For breed factor, only the durations of the eating presented significant differences (p-value< 0.05). For cage density, there was a significant median difference (p-value< 0.05) for almost all behaviors observed. The average length of time of behaviors was higher for the lowest cage density. However, the frequency of behaviors was lmerfor the lowest cage density. The frequency of the behaviors to preen feathers, to lie down, to drink water and to stretch the head were higher in the aviary, where the groups of birds were smaller. The observed behaviors were particularly affected by experimental factors cage density, and aviary type, which directly affects the available space for each bird.

First telemetry study of bush dogs: Home range, activity and habitat selection

Context The bush dog (Speothos venaticus) is difficult to observe, capture, and study. To date, indirect evidence and opportunistic field observations have been the primary sources of information about the species' ecology. Field data are urgently needed to clarify the species' ecological requirements, behaviour and movement patterns. Aims The present study uses 13 months of telemetry data from a group of bush dogs to begin to address questions about area requirements, habitat preferences and movement patterns of this difficult-to-study species. Methods We tracked a group of bush dogs (two adults, one juvenile, four young) in an area of intact and altered Cerrado (woodlandsavanna biome) in eastern Mato Grosso, Brazil (Nova Xavantina District). Key results The group had a total home range of 140km2 (fixed kernel 95%), with smaller seasonal 'subareas' (areas used for 12 months before moving to another area, with repetition of some areas over time) and demonstrated a preference for native habitats. Conclusions The bush dog's home range is greater than that of other canids of the same size, even correcting for group size. Patterns of seasonal movement are also different from what has been observed in other South American canids. Implications From our observations in the Brazilian savanna, bush dogs need large tracks of native habitat for their long-term persistence. Although the present study is based on a single pack, it is highly relevant for bush dog conservation because it provides novel information on the species' spatial requirements and habitat preferences. © 2012 CSIRO.