The wartbiter spermatophore and its effect on female reproductive output (Orthoptera: Tettigoniidae,Decticus verrucivorus)

Summary Male wartbiters Decticus verrucivorus transfer elaborate spermatophores to females during copulation. The spermatophore is attached externally to the female's genitalia and consists of two parts: a large, gelatinous, sperm-free portion, the spermatophylax, eaten by the female after mating; and a sperm-containing ampulla, eaten after the spermatophylax has been consumed. Since females take longer to eat larger spermatophylaxes, the duration of ampulla attachment is positively correlated with spermatophylax size. Two series of experiments were carried out, one in which the size of the spermatophylax consumed by females and the duration of ampulla attachment were manipulated in concert and another in which they were manipulated independently. Some females were also maintained on a protein-free diet and either supplied with or deprived of spermatophylax material. The amount of protein in the diet, but not the amount of spermatophylax material consumed, influenced female longevity, lifetime fecundity, and egg weight. When females were deprived of the spermatophylax, an experimental increase in the duration of ampulla attachment induced longer periods of unreceptivity in females after mating, a more rapid onset of oviposition, and an increased oviposition rate. Consequently, the number of eggs laid by females during their nonreceptive refractory periods increased significantly with increasing duration of ampulla attachment up to 180 min; however, there was no significant increase in the number of eggs laid beyond 180 min of ampulla attachment. This closely corresponds to an ampulla attachment duration of 188 min expected when a male transfers a natural spermatophylax of mean size to the female. These results suggest that the amount of ejaculate transferred to the female, and not the amount of spermatophylax material per se, is the factor controlling female receptivity and oviposition behavior. Since we did not detect any effect of spermatophylax consumption on female fecundity or egg weight, we conclude that the spermatophylax of D. verrucivorus functions primarily as a sperm protection device rather than as a form of male parental investment.     

农村生活污水处理技术

农村城市化发展迅速,而农村水污染情况日益严重,已对农村地区的水体、土地等自然环境产生严重影响。为建立和谐新农村,保障农村生活质量提高,缩小城乡差距,必须重视农村水源安全。本文就农村生活污水处理技术进行讨论,为农村发展提供参考。     

Potassium, phosphorus, or nitrogen limit root allocation, tree growth, or litter production in a lowland tropical forest

We maintained a factorial nitrogen (N), phosphorus (P), and potassium (K) addition experiment for 11 years in a humid lowland forest growing on a relatively fertile soil in Panama to evaluate potential nutrient limitation of tree growth rates, fine-litter production, and fine-root biomass. We replicated the eight factorial treatments four times using 32 plots of 40 x 40 m each. The addition of K was associated with significant decreases in stand-level fine-root biomass and, in a companion study of seedlings, decreases in allocation to roots and increases in height growth rates. The addition of K and N together was associated with significant increases in growth rates of saplings and poles (1-10 cm in diameter at breast height) and a further marginally significant decrease in stand-level fine-root biomass. The addition of P was associated with a marginally significant (P = 0.058) increase in fine-litter production that was consistent across all litter fractions. Our experiment provides evidence that N, P, and K all limit forest plants growing on a relatively fertile soil in the lowland tropics, with the strongest evidence for limitation by K among seedlings, saplings, and poles.     

登陆中国台风灾害损失预评估模型研究

整理了2000-2008年登陆中国且灾情记录完整的34个台风案例,建立案例集;基于模糊数学法建立了台风灾害损失预评估模型。选择8项影响因子作为模型输入指标,利用层次分析法确定影响因子权重,计算案例集中每个台风的综合评价指数;通过对综合评价指数与受灾人口、农作物受灾面积及直接经济损失等典型灾情指标进行拟合;通过适当调整影响因子权重,拟合得出最优幂函数回归方程,从而实现对台风灾情的定量预评估。     

Dynamics and origin of PM2.5 during a three-year sampling period in Beijing, China

Systematic sampling and analysis were performed to investigate the dynamics and the origin of suspended particulate matter smaller than 2.5 μm in diameter (PM(2.5)), in Beijing, China from 2005 to 2008. Identifying the source of PM(2.5) was the main goal of this project, which was funded by the German Research Foundation (DFG). The concentrations of 19 elements, black carbon (BC) and the total mass in 158 weekly PM(2.5) samples were measured. The statistical evaluation of the data from factor analysis (FA) identifies four main sources responsible for PM(2.5) in Beijing: (1) a combination of long-range transport geogenic soil particles, geogenic-like particles from construction sites and the anthropogenic emissions from steel factories; (2) road traffic, industry emissions and domestic heating; (3) local re-suspended soil particles; (4) re-suspended particles from refuse disposal/landfills and uncontrolled dumped waste. Special attention has been paid to seven high concentration "episodes", which were further analyzed by FA, enrichment factor analysis (EF), elemental signatures and backward-trajectory analysis. These results suggest that long-range transport soil particles contribute much to the high concentration of PM(2.5) during dust days. This is supported by mineral analysis which showed a clear imprint of component in PM(2.5). Furthermore, the ratios of Mg/Al have been proved to be a good signature to trace back different source areas. The Pb/Ti ratio allows the distinction between periods of predominant anthropogenic and geogenic sources during high concentration episodes. Backward-trajectory analysis clearly shows the origins of these episodes, which partly corroborate the FA and EF results. This study is only a small contribution to the understanding of the meteorological and source driven dynamics of PM(2.5) concentrations.     

Silver nanoparticles induce histopathological alterations in juvenile Penaeus vannamei

Environmental Science and Pollution Research - The objective of this study was to evaluate the histopathological alterations in juvenile Penaeus vannamei caused by silver nanoparticles (AgNPs) for...     

Physical Strain and Work Ergonomics in Farmers with Disabilities

In agriculture, occupational injuries are common, and several of them lead to permanent physical disability. The objective of this case study was to assess the strain and the ergonomic needs of four farmers (aged 34–49 years) with physical disabilities. A maximal bicycle ergometer test or an arm-crank test was done to assess their maximal heart rate (HR _max) and maximal oxygen consumption (V0_2max). The strain at work was analyzed by measuring heart rate (HR), muscle activity (EMG), and the rating of perceived exertion (RPE). The farmers were interviewed as to possible and impossible work tasks and the ergonomic redesign measures taken to improve the work environment. The work tasks performed were mainly light or moderate work for the cardiorespiratory system according to mean HR (88-102 beats/min), the percentage of HR range (17–31% HRR), and the relative V0₂ (22–46% V0_2max). The mean activity of the trapezius muscles was 0.4-9% of the maximal voluntary contraction (%MVC). All the participants had work tasks they were unable to perform. They had made ergonomie redesign changes mainly to the tractor. This case study showed that some agricultural work tasks were possible for farmers with physical disabilities and that the physical strain associated with these tasks was mainly light or moderate.