Hymenoptera such as bees and social wasps are regular floral visitors in "campos rupestres" vegetation. A community of bees and social wasps was studied during floral visitation in an area of "campos rupestres", at Chapada Diamantina, BA, Brazil, from September 2001 to April 2002. The community was described in relation to diversity, evenness, and dominance rank, considering the individuals abu...

We previously found a dominant eye perceptional advantage in feature search (Vision Research, 2006). We now ask if this advantage extends to difficult conjunction search, which requires focused attention and depends on different cortical hierarchy levels. We determined eye dominance by the Hole-in-the-Card test. Using red-green glasses, subjects viewed a briefly presented, backward-masked, arra...

The most dramatic example of experience-dependent cortical plasticity is the shift in ocular dominance that occurs in visual cortex as a consequence of monocular deprivation during early postnatal life. Many of the basic properties of this type of synaptic plasticity have been described in detail. The important challenge that remains is to understand the molecular basis for these properties. By...

In the current study we investigated whether the developmental status of the two largest follicles (LF1 and LF2) at the time of administration of the first two doses (0 and 12 h) of FSH of a superovulatory treatment influences periovulatory events and embryo yields in sheep. A larger size of LF1 was negatively correlated with embryo recovery (r=-0.608 for 0 h and r=-523 for 12 h, p<0.05), ferti...

Hebbian and homeostatic plasticity together refine neural circuitry, but their interactions are unclear. In most existing models, each form of plasticity directly modifies synaptic strength. Equilibrium is reached when the two are inducing equal and opposite changes. We show that such models cannot reproduce ocular dominance plasticity (ODP) because negative feedback from the slow homeostatic p...

We introduce the problem of Weak Dominance Drawing for general directed acyclic graphs and we show the connection with the linear extension diameter of a partial order P . We present complexity results and bounds.

bahrakan region is one of the four important and major areas of oil and economy in the persian gulf. the aim of this study was to evaluate the use of meiofauna as bioindicator of environmental pollution and the influence of organic contaminants on variation of meiofauna. sampling has done from 9 stations in three transects perpendicular to the intertidal shoreline, in the cold season (winter 20...