72 resultados para spider egg sac


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The purpose of this single-center study was to report our initial experience with an implantable remote pressure sensor for aneurysm sac pressure measurement in patients post-endovascular aneurysm repair (EVAR) including short-term follow-up. A pressure sensor (EndoSure, Atlanta, GA) was implanted in 12 patients treated with different commercially available aortic endografts for EVAR. Pressure was read pre- and post-EVAR in the operating room. One-month follow-up (30 days +/- 6 days) was performed including sac pressure readings and IV contrast CT scans. Variables were compared using the paired Student's t test. An intraprocedure type-I endoleak and a type-III endoleak were successfully treated resulting in decreasing sac pressures. In all patients, post-EVAR systolic sac pressure decreased by an average of 33% (P sac pressure (P sac was larger only in one patient with a type-III endoleak. Remote sac pressure measurement may provide important information in addition to imaging and may help to reduce the number of follow-up CT scans.

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Mothers should adjust the size of propagules to the selective forces to which these offspring will be exposed. Usually, a larger propagule size is favored when young are exposed to high mortality risk or conspecific competition. Here we test 2 predictions on how egg size should vary with these selective agents. When offspring are cared for by parents and/or alloparents, protection may reduce the predation risk to young, which may allow mothers to invest less per single offspring. In the cooperatively breeding cichlid Neolamprologus pulcher, brood care helpers protect group offspring and reduce the latters' mortality rate. Therefore, females are expected to reduce their investment per egg when more helpers are present. In a first experiment, we tested this prediction by manipulating the helper number. In N. pulcher, helpers compete for dispersal opportunities with similar-sized individuals of neighboring groups. If the expected future competition pressure on young is high, females should increase their investment per offspring to give them a head start. In a second experiment, we tested whether females produce larger eggs when perceived neighbor density is high. Females indeed reduced egg size with increasing helper number. However, we did not detect an effect of local density on egg size, although females took longer to produce the next clutch when local density was high. We argue that females can use the energy saved by adjusting egg size to reduced predation risk to enhance future reproductive output. Adaptive adjustment of offspring size to helper number may be an important, as yet unrecognized, strategy of cooperative breeders.

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Cognitive-motivational theories of phobias propose that patients' behavior is characterized by a hypervigilance-avoidance pattern. This implies that phobics initially direct their attention towards fear-relevant stimuli, followed by avoidance that is thought to prevent objective evaluation and habituation. However, previous experiments with highly anxious individuals confirmed initial hypervigilance and yet failed to show subsequent avoidance. In the present study, we administered a visual task in spider phobics and controls, requiring participants to search for spiders. Analyzing eye movements during visual exploration allowed the examination of spatial as well as temporal aspects of phobic behavior. Confirming the hypervigilance-avoidance hypothesis as a whole, our results showed that, relative to controls, phobics detected spiders faster, fixated closer to spiders during the initial search phase and fixated further from spiders subsequently.