Prevalence of Anophelines (Diptera: Culicidae) during sunset in areas of the Itaipu Hydroelectric plant in Guaíra county, state of Paraná, Brazil

Systematic collections of anophelines were conducted from November 1994 to August 1995 from 18:00 to 20:00 hr using Shannon traps and human-bait along the lake margin which forms the Itaipu Hydroelectric reservoir, State of Paraná, Brazil. Species prevalence was studied at 15 min intervals. Anopheles albitarsis sensu latu and An. galvaoi, were the most frequently collected mosquitoes. All Anopheles species populations peaked between 18:45 and 19:30 hr. The observations illustrate the existence of a haematophagic activity cycle during the early evening hours: exogenous stimulus (the beginning of sunset)-->Shannon trap (light attraction)-->human bait (haematophagy)-->rest and digestion-->exogenous stimulus-->Shannon trap or surrounding vegetation. The greater abundance of An. albitarsis collected in human-bait and Shannon trap suggests it may be a potential malaria vector in the region.     

Supplementary cues and delayed-alternation performance of frontal monkeys.

Tested 4 female and 3 male rhesus monkeys that had sustained total or partial ablation of dorsolateral frontal cortex in the Wisconsin General Test Apparatus under variations of the delayed-alternation (DA) task involving supplementary articular-somesthetic or kinesthetic cues. DA performance improved when supplementary articular-somesthetic cues were introduced. Ss with ablation of sulcus principalis demonstrated improvement on DA when supplementary kinesthetic cues were provided; Ss with total dorsolateral ablation did not. Findings support the concept of prefrontal cortex as a gnostic area of the kinesthetic analyzer. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effect of nutrition on the response of field populations of the calanoid copepod Acartia tonsa to copper

Continuous flow toxicity tests were conducted on field populations of adult Acartia tonsa collected from Narragansett Bay. Potential algal food at the collection site was estimated from ATP and chlorophyll analysis. There was positive correlation (P < 0.01) between chlorophyll a and ATP. Integration of these data with quantitative zooplankton analysis established that A. tonsa had a significant grazing effect on algal biomass (P < 0.05). The natural population dynamics of A. tonsa during this period were assessed from microscopic analysis of tow material.The sensitivity of A. tonsa to total copper ranged from 9.0 to 78.0 μg l⁻¹ for 72 h LC50's. Results show an inverse correlation (P < 0.05) between the log LC50 and adult A. tonsa density at the time of collection. The relationship between A. tonsa sensitivity to copper and the food ration (algal density/A. tonsa density) has been described by a quadratic function which has a correlation coefficient of 0.78. This indicates that the log LC50 increases with increasing food ration up to a point and then remains constant. A comparison of confidence intervals about the LC50's indicates greater variability in the response of field animals compared to previous studies with cultured populations. This data suggests that field populations of A. tonsa can be expected to exhibit a wide range of sensitivity to other pollutants. Sensitivity is strongly correlated with population density and food ration.     

Histopathology of the digestive gland of an Antarctic limpet exposed to cadmium

Histopathological alterations induced experimentally with cadmium (Cd) in Antarctic limpets (Nacella concinna), exposed for different times and concentrations were compared to controls. At the light microscope level, samples exposed to the contaminant for short periods (6, 12 and 24 h) at two different concentrations (0.25 and 0.5 mg l(-1)) showed no alterations compared to controls. After 48 h of exposure at a 0.5 mg l(-1) Cd concentration, vacuolisation of the basophilic cells was observed. After 72 h exposure, there was a marked loss of all the digestive gland structure, with cell autolysis and loss of basophilia.     

动态电源管理技术优化嵌入式应用性能与功耗比

消费者对采用多媒体嵌入式处理器产品的需求迅速增长,这既要求提高性能又要求降低功耗.但是高性能处理必须增加计算复杂度并加快时钟速率,如果采用权宜之计的节省功耗设计方案,是很难实现的.我们需要的是一种具有战略意义的方法来管理功耗,以便在具体的嵌入式应用中优化性能与功耗的关系.利用Blackfin数字信号处理器(DSP)系列产品固有的动态电源管理能力,可以实现这样的方法.     

以模块为基础的薄带材和箔材平直度控制

薄带材和箔材的平直度或板形控制必然要求一定程度的模型化。这是由于轧钢工艺本身的复杂性所要求的。描述在轧制带卷前到形成良好初始平直度的最佳轧制程序表及在高平直度控制情况下生产带卷的过程中使用的模块。集中讨论在普通4辊铝薄带和箔材轧机上所用的平直度模块。     

Stress triaxiality effect on void nucleation in ductile metals

The stress triaxiality effect on the strain required for void nucleation by particle‐matrix debonding has been investigated by means of micromechanical modelling. A unit‐cell model considering an elastic spherical particle embedded in an elastic‐plastic matrix was developed to the purpose. Particle‐matrix decohesion was simulated through the progressive failure of a cohesive interface. It has been shown that the parameters of matrix‐particle cohesive interface are correlated with macroscopic material properties. Here, a simple relationship for the maximum cohesive opening at interface failure as a function of material fracture toughness and yield stress has been derived. Results seem to confirm that, increasing stress triaxiality, the strain at which void nucleation is predicted to occur decreases exponentially in a similar way as for fracture strain. This result has substantial implications in modelling of ductile damage because it indicates that if the stress triaxiality is high enough, ductile fracture can occur at plastic strain lower than that necessary to nucleate damage for moderate or low stress triaxiality regime.     

Organized porous alumina membranes for high density silicon nanowires growth

In this paper, we present results on the fabrication of porous alumina membranes on silicon substrates with a long-range order induced by nanoimprint lithography. Fabricated porous alumina matrices present a perfect triangular array of vertical cylindrical pores on areas of 500 × 500 μm² corresponding to the imprinted surfaces. Also, we demonstrate that it is possible to have a directed density multiplication during the pore formation, compared to the nanoimprint mold, by the initial indentation of only one third of the expected alumina pores. The gold catalyst, needed for nanowires growth, is deposited at the bottom of each pore by electrochemistry. The proposed process is scalable to wafer-scale areas, compatible with microelectronics fabrication standards and is not limited to non-fragile substrates like direct bulk aluminum nanoindentation.     

Nanoscale structuration and optical properties of thin gold films on textured FTO

In this work, we propose a methodology to synthesize metallic nanoparticles on textured Fluorine Tin Oxide (FTO) surface by laser irradiations of deposited Au films. In particular, the breakup of the Au films into nanoparticles (NPs) is observed as a consequence of the melting and solidification processes induced by laser irradiations. The mean Au NPs size and surface density evolution are analyzed as a function of the laser fluence. Optical characterizations of the glass/FTO/Au NPs multilayer show, in the absorption spectra, plasmonic peaks due to the Au NPs and an improvement of the light absorption efficiency from the sample with larger Au NPs. The simulated trends of the ratio between the scattering and absorption cross section suggest that the absorption efficiency dominates over the scattering efficiency in the spectral range between 200 and 600 nm. The simulation shows that, by varying the NPs radius from about 18 to 24 nm, the radiation-scattered intensity remains symmetric in forward and reverse directions. These results indicate that the surface coverage size distribution of Au NPs is the key parameter to correlate the structural and optical properties of the glass/FTO/Au NPs multilayer. Furthermore, electrical characterizations highlight a reduction in the sheet resistance of the textured FTO due to the presence of the NPs. We compare these results with those obtained for the same systems when standard furnace annealing processes are used to obtain the Au NPs on the textured FTO surface.