No abstract

The effects of three concentrations of neomycin, administered by a method of acute perilymphatic perfusion of the guinea pig cochlea, on the cochlear microphonic potential (CM) at 4 kHz and 500 Hz are described. A concentration-dependent reduction in CM occurred during the 60 minute perfusion period. Neomycin at M did not change the CM magnitude, while at M it caused 4 kHz (and 500 Hz) CM reductions which began within 24 (for both frequencies) minutes and 10 (and 12) minutes of drug application respectively. CM reduction proceeded at a higher rate for greater neomycin concentration. The perfusion technique, the implication of the frequency indifference, and the potential of the perfusion technique for inner ear biochemical analysis are discussed. and 26 -772954 Acta Otolaryngol83 Acta Otolaryngol Downloaded from informahealthcare.com by McMaster University on 11/05/14 For personal use only. Acta Otolaryngol Downloaded from informahealthcare.com by McMaster University on 11/05/14 For personal use only. Acta Otolaryngol Downloaded from informahealthcare.com by McMaster University on 11/05/14 For personal use only. Acta Otolaryngol Downloaded from informahealthcare.com by McMaster University on 11/05/14For personal use only.

The aggressive behaviour of female hamsters was studied while they were housed in large enclosures with males and in brief tests with males or females. Some females are not aggressive with any male, whereas others are very aggressive toward all males in both testing conditions. Females that are not aggressive toward intact males may be very aggressive toward castrated males or females. When the animals are housed together for long periods of time, males dominate only if they are much heavier. Male dominance takes a relatively long time to establish and often there is an equivocal period characterized by reversals of dominance. Female dominance is rapidly established. Unless the male is much heavier, the female determines the presence or absence of agonistic behaviour.

No abstract

A series of experiments was undertaken to investigate the roles of the main olfactory and vomeronasal systems in the response of the female golden hamster (Mesocricetus auratas) to pups. Upon first encountering hamster pups, virgin females are either maternal or cannibalistic. Radical bulbectomy, which disrupts both the main and accessory bulbs, reduced maternal behavior, pup killing, and nest building. Many animals neither killed nor carded pups following radical bulbectomy, and some previously maternal animals attacked pups after bulbectomy. The effects of bulbectomies were not reproduced by peripheral deafferentations (sensory loss only) of the main olfactory and vomeronasal systems. After vomeronasal nerve cuts (VNNC) most killers became carders and built better nests than before deafferentation. Zinc sulfate treatment (main olfactory system sensory loss) alone had little effect, but when combined with transection of the vomeronasal nerves, it converted to carriers those killers that had continued to kill after VNNC. Because none of these procedures affected cricket killing, the treatments that reduced pup killing appear to be stimulus rather than response related. The behavior pattern displayed during cricket killing was similar to that observed during pup killing.

Fundação pública vinculada ao Ministério da Economia, o Ipea fornece suporte técnico e institucional às ações governamentais-possibilitando a formulação de inúmeras políticas públicas e programas de desenvolvimento brasileiros-e disponibiliza, para a sociedade, pesquisas e estudos realizados por seus técnicos. 1. Nesse conceito, estão agrupadas as categorias agressões (110) e intervenções legais (112) da 10ª revisão da Classificação Internacional de Doenças adaptada à realidade brasileira (CID-BR-10), segundo o Sistema de Informação sobre Mortalidade/Secretaria de Vigilância em Saúde/Ministério da Saúde (SIM/SVS/MS).

The response of virgin male and female golden hamsters to young was studied. In contrast to most species, males are more likely to carry pups than are females. All males carried pups, but approximately 50% of females cannibalized the young. The females that did not cannibalize the pups carried them with less hesitation and after shorter latencies than did the males. The response of females to young was not correlated with the aggressiveness displayed toward adult males during separate tests. Tests with gonadectomized females indicated that the maintenance of pup-killing behavior is not dependent on concurrent gonadal hormones. Progesterone injections did not significantly increase pup killing in males that had previously carried young. Speculations on the adaptive significance of the male and female hamster's response to pups are presented.

a b s t r a c tA renewed interest on the impacts of climate change has spurred several studies on climate/health relationships. This study aims to detect and explain any changes in the relationships between climate and mortality in Lisbon from 1835 until 2012. The evaluation of mortality seasonal rhythms over time is based on the 100-Index per decades, annual Winter-Summer ratio, as well as other descriptive statistics. A change in the seasonal rhythm of mortality over the last 177 years was found. In the mid-19th century mortality peaked in summer, whereas in the 1890s and the 1900s there was slight monthly variability. On the contrary, a winter maximum has occurred since the 1940s, although a secondary summer peak of mortality may emerge during the most severe heat-waves. Although long term positive temperature trends were confirmed, no systematic positive mortality trends were found in the last three decades. The results suggest that mortality rhythm changes during the 19th and 20th century are not directly related to climatic reasons alone (except in the case of extreme weather events), but rather to improvements in hygienic, sanitary and nutrition conditions and advances in medicine. However, given the possible increase of summer heat waves in the future, and individuals increasing vulnerability, particularly in urban areas, such secondary peaks of mortality will tend to happen more frequently, unless adaptation of populations to hotter conditions takes place and/or measures are taken to protect people from high temperatures.