Cooperative breeding is a phenomenon whereby breeding and nonbreeding individuals collectively provision young. Nonbreeding group members ("helpers'') may gain indirect and/or direct fitness benefits by breeding in a group, but there has been conflicting evidence regarding the benefits to breeders. In fact, the presence of helpers may sometimes be detrimental to aspects of breeder fitness. For example, in some species of the chiefly Australian genus Malurus, breeding males with helpers have lower within-pair paternity than do males without helpers. Additionally, indirect benefits to breeding males are often limited by low relatedness to their helpers due to high extrapair paternity rates, and helpers often appear to have minimal impact on breeder reproductive success. However, the presence of helpers may allow breeding males to shift their behaviors from guarding and provisioning young to alternative behaviors that affect other components of fitness, such as extraterritory forays (which might increase extrapair mating success) and self-maintenance (which might increase survival). We investigated these possibilities in the facultatively cooperative Red-backed Fairywren (Malurus melanocephalus). Males with helpers spent significantly less time engaging in guarding behaviors and provisioning of young than did those without helpers, but there was no difference in the frequency of extrapair forays nor the number of young sired by males with vs. without helpers. Additionally, the decreased investment in nesting behaviors did not result in consistently higher survival, but may have increased survival in some years. Overall, the results of this study did not suggest any strong direct fitness benefits to breeding males, which may indicate that the costs of retaining helpers are negligible relative to the indirect benefits of helping a potentially related male.

Dendrochronologists have used the presence of spiral grain as an indicator of old trees for most of the history of the field, although this relationship has been little studied. We examined cross-sections from dead trees and used a 12-mm Haglof Swedish Increment borer to collect cores from living white oak (Quercus alba L.) trees in an Eastern Deciduous Forest stand in southwestern Illinois. Spiral grain is the alignment of wood fibers to the longitudinal axis of trees and is driven by patterns of initial cambial cell division. In this study, we examine environmental factors that may affect spiral grain severity, the usefulness of non-destructive sampling methods (using the 12-mm increment borer), and the relationship between tree age and spiral grain. We tested Brazier’s method (1965) of averaging the spiral grain angle from two radii taken 180 degrees apart (i.e. one diameter in the tree) to get representative grain angles for the whole circumference of a tree at a certain height. The 12-mm increment borer did not produce consistent results in this study; therefore, the collection of cross-sections is advised for the study of spiral grain in white oaks. Brazier’s method should not be used in white oaks and should not be applied universally to all tree species. The severity of spiral grain is expressed in the xylem and may not be expressed in the bark of the tree. Left spiral grain does generally increase in white oaks with age, although this relationship is not always consistent, so a tree without severe spiral grain is not necessarily young.

Young football players are hypothesized to experience damage to the brain and brain function from repeated subconcussive head acceleration events (HAEs) during practices and games. Such damage may cause delayed cognitive and mental problems. Resting state fMRI (rs-fMRI) is an effective non-invasive method to detect alterations in brain functional connectivity. Seed-based rsfMRI analysis using the central node of the default mode network (DMN) as the seed is a common approach to measuring intrinsic changes of the DMN, accepted as a key network in brain function. Seed-based rs-fMRI analysis of the DMN was used to explore how age, HAE intensity, and HAE counts influence brain connectivity in youth athletes (ages 12-18). Middle school and high school football players and peer controls were studied using rs-fMRI before and after one season of competition. An identifiability matrix was generated from the seed-based connectivity matrix, allowing measurement of similarity between pre-season and post-season functional connectivity. The consistency of seed-based brain functional connectivity we observed across the season of play for players has no statistically significant difference from controls. The identifiability matrix exhibited no relation to the number and magnitude of any subset of HAEs experienced which rejected our hypothesis. Another finding is that high school football players exhibited the largest percentage increase in identification from middle school football players in the somatomotor network over other resting-state networks.

Made available in DSpace on 2016-03-15T19:25:33Z (GMT). No. of bitstreams: 1 Eliana Cruz Yoshida.pdf: 832230 bytes, checksum: 2a96519ccc0f980ce7dead070bae704a (MD5) Previous issue date: 2011-02-17 / Fundo Mackenzie de Pesquisa / This study analyzes the demography of the multiple banks in Brazil by utilizing longitudinal data which expands between periods of 1988 until 2009. The purpose of this research is analyzes the evolution of multiple banks, on these aspects: organizational diversity, age and mortality. Mainly, a multiple bank s origin can be: a) bank sector when the multiple bank originates from a development bank, a commercial bank or an investment bank; b) none-bank sector when the multiple bank birth from another kind of financial company, except banks. At first, through a perspective of the Ecology Organizational Theory, this research analyzes the organizational form of these banks that was in activity, and through an application of clusters analysis showing this population s feature and its organizational diversity. Then second, by utilizing the Weibull model, it is generated a life data analysis to identify, among others results, positive age dependence in mortality (cancelation) rates for these Brazilian multiple banks, describing a liability of obsolescence or senescence. At last, by using two statistical techniques (test chi-square and Weibull model), it was possible to gather evidence that a relationship exist between source and cancelation rates, because multiple banks that began its activity in none-bank sector have been canceled faster than those that began in bank sector; moreover, cancelation rates for this population varies depending on the bank s origin. The main value of this research is the fact that it is a population demography study in retrospect to life and death of multiple banks, an issue that has not been explored at national academic literature in depth. / Este estudo realiza uma análise demográfica da população dos bancos múltiplos no Brasil, por meio de um estudo longitudinal, que abrange o período de 1988 a 2009. O objetivo geral desta pesquisa é analisar a evolução da população de bancos múltiplos no Brasil a partir da diversidade organizacional, idade e mortalidade dessas instituições financeiras. Um banco múltiplo, geralmente, nasce a partir de outra instituição financeira que já atuava no Sistema Financeiro Nacional e que se transforma nesse tipo de banco. Portanto, a origem dos bancos múltiplos pode ocorrer dentro de dois grupos: a) do setor bancário - quando o banco múltiplo nasce da transformação de um banco comercial, banco de investimento ou banco de desenvolvimento; b) do setor não bancário quando o banco múltiplo nasce da transformação de uma sociedade corretora de títulos e valores mobiliários, sociedade distribuidora de títulos e valores mobiliários, sociedade de crédito, financiamento e investimento, sociedade de arrendamento mercantil, sociedade de crédito imobiliário ou caixa econômica. Sob a perspectiva da Teoria Ecológica das Organizações, em um primeiro momento, este trabalho analisa a forma organizacional dos bancos múltiplos em atividade, por meio de uma análise de agrupamentos, identificando o perfil dessa população e a sua diversidade organizacional. Em um segundo momento, com o emprego do modelo baseado na distribuição Weibull, é realizado uma análise de dados de vida da população estudada, identificando, entre outros resultados, a dependência positiva da idade nas taxas de cancelamento, descrevendo uma suscetibilidade da obsolescência ou da senescência. Por fim, com a aplicação de duas ferramentas estatísticas, o teste qui-quadrado e a distribuição Weibull, evidencia-se que existe relação entre a origem e a idade de cancelamento desses bancos, tendo em vista que os bancos múltiplos provenientes do setor não bancário têm sua autorização para funcionamento cancelada mais rapidamente do que os provenientes do setor bancário; além disso, as taxas de cancelamento para a população variam, dependendo da origem desses bancos. A principal contribuição desta pesquisa é justamente o fato de ser um estudo de demografia populacional, assunto pouco explorado na literatura acadêmica nacional.