Organochloride pesticides in California sea lions revisited

Background  

Dichlorodiphenyltrichloroethane (DDT) and polychlorinated biphenyls (PCBs) are ubiquitous environmental contaminants that have been banned in most countries, but considerable amounts continue to cycle the ecosphere. Top trophic level predators, like sea birds and marine mammals, bioaccumulate these lipophilic compounds, reflecting their presence in the environment.     

In utero domoic acid toxicity: a fetal basis to adult disease in the California sea lion (Zalophus californianus)

California sea lions have been a repeated subject of investigation for early life toxicity, which has been documented to occur with increasing frequency from late February through mid-May in association with organochlorine (PCB and DDT) poisoning and infectious disease in the 1970’s and domoic acid poisoning in the last decade. The mass early life mortality events result from the concentrated breeding grounds and synchronization of reproduction over a 28 day post partum estrus cycle and 11 month in utero phase. This physiological synchronization is triggered by a decreasing photoperiod of 11.48 h/day that occurs approximately 90 days after conception at the major California breeding grounds. The photoperiod trigger activates implantation of embryos to proceed with development for the next 242 days until birth. Embryonic diapause is a selectable trait thought to optimize timing for food utilization and male migratory patterns; yet from the toxicological perspective presented here also serves to synchronize developmental toxicity of pulsed environmental events such as domoic acid poisoning. Research studies in laboratory animals have defined age-dependent neurotoxic effects during development and windows of susceptibility to domoic acid exposure. This review will evaluate experimental domoic acid neurotoxicity in developing rodents and, aided by comparative allometric projections, will analyze potential prenatal toxicity and exposure susceptibility in the California sea lion. This analysis should provide a useful tool to forecast fetal toxicity and understand the impact of fetal toxicity on adult disease of the California sea lion.     

茶皂素在农药上的应用研究概况

本文从茶皂素对有害生物的生物活性及其对农药的增效作用等方面阐述了茶皂素的研究进展,并就茶皂素的生物活性和增效作用机制进行了初步探讨。     

Erratum to: Water management strategies for hydropower annexation at existing irrigation dams in Japan

Paddy and Water Environment -     

实施HACCP原理降低崂山绿茶农药残留量的研究

崂山绿茶产自青岛崂山山脉。近几年发展迅速,现有茶园面积约有1867公顷。由于崂山绿茶已成为国内外游客首选特色旅游产品,也将是2008年奥运会外国游客在青岛期间的消费品。本文根据崂山茶区的地理环境和茶树管理现状及技术,应用HACCP原理建立了崂山绿茶的HACCP操作技术规范体系,并从2001年起在崂山茶区由点到面进行了应用推广。实施崂山绿茶HACCP操作技术后,崂山绿茶中农药残留量,经中国农业部茶叶质量检验监督中心2004～2005年连续二年来的抽查检测,无论是按现行的国家无公害茶叶标准,还是现行的欧盟茶叶标准均无农药残留超标,合格率达100%。     

Erratum to: Feeding preferences of the Asian elephant (Elephas maximus) in Nepal

Background

The relationships between group size, survival, and longevity vary greatly among social species. Depending on demographic and ecological circumstances, there are both positive and negative effects of group size variation on individual survival and longevity. For socially foraging species in particular there may be an optimal group size that predicts maximum individual survival that is directly related to the potential for information transfer, social coordination, and costs of conspecific interference. Our aim was to investigate this central aspect of evolutionary ecology by focusing on a socially foraging bat, Molossus molossus. This species optimizes foraging success by eavesdropping on the echolocation calls of group members to locate ephemeral food patches. We expected to find the highest survival and longest lifespans in small groups as a consequence of a trade-off between benefits of information transfer on ephemeral resources and costs of conspecific interference.

Results

In a mark-recapture study of 14 mixed-sex M. molossus social groups in Gamboa, Panama, spanning several years we found the expected relatively small and intermediate, but stable groups, with a mean size of 9.6 ± 6.7 adults and juveniles. We estimated survival proxies using Cox proportional hazard models and multistate-mark recapture models generated with recapture data as well as automated monitoring of roost entrances in a subset of the groups. Median survival of females was very short with 1.8 years and a maximum estimated longevity of 5.6 years. Contrary to our expectations, we found no relationship between variation in group size and survival, a result similar to few other studies.

Conclusions

Strong selection towards small group size may result from psychoacoustic and cognitive constraints related to acoustic interference in social foraging and the complexity of coordinated flight. The short lifespans were unexpected and may result from life at the energetic edge due to a highly specialized diet. The absence of a relationship between group size and survival may reflect a similar but optimized survival within the selected range of group sizes. We expect the pattern of small group sizes will be consistent in future research on species dependent on social information transfer about ephemeral resources.

     

不同农药防治假眼小绿叶蝉药效试验

假眼小绿叶蝉为茶树重要害虫，以成、若虫剌吸茶树新梢汁液，被害嫩叶失绿，芽梢枯焦萎缩，质地变脆，严重影响茶叶的产量及品质。为探讨不同农药对假眼小绿叶蝉的防治效果，我站在茶园中进行药效试验。     

The environmental yardstick for pesticides: a practical indicator used in the Netherlands

The environmental yardstick for pesticides has been developed as a tool for farmers to select pesticides with the least environmental impact and to quantify the impact of their use at the crop/farm level, regional level and national level. For each pesticide the yardstick assigns environmental impact points for the risk to water organisms, the risk of groundwater contamination and the risk to soil organisms. It is presently used in the Netherlands as a management tool for farmers and technical consultants, as a tool for monitoring the environmental performance of farmers, as a tool for setting standards for ecolabels and as a policy evaluation tool.     

Developing a pesticide risk assessment tool to monitor progress in reducing reliance on high-risk pesticides

A methodology is presented for the development of a pesticide risk assessment tool that was used to monitor progress in reducing use of high-risk pesticides in Wisconsin potato production. Multi-attribute toxicity factors are calculated that reflect each pesticide’s acute and chronic toxicity to mammals, birds, fish and small aquatic organisms, and compatibility with biointensive Integrated Pest Management. These factors are then multiplied by the pounds of active ingredient of a given pesticide applied to estimate pesticide-specific toxicity units. Wisconsin potato industry baseline toxicity units by type of pesticide and for 11 targeted higher-risk pesticides are presented for 1995. Reductions in toxicity units from this baseline are reported for 1997 and 1999, as are reductions achieved in a commercial-scale field experiment in 2000.     

Maps, models, and muddles: world trends and patterns in potatoes revisited

Summary This paper examines trends and prospects for potatoes in developed and developing countries with an eye to incorporating a policy, historical, and quantitative perspective into that analysis. The available evidence indicates production surged ahead in many developing countries since 1960, while it stagnated or sharply declined in many, albeit not all, developed countries. Potato tubers are often sold as a high-priced vegetable in developing countries and marketed as a cheap, staple food in much of Europe and North America. Besides changes in incomes and consumers’ quest for more diverse diets, government policy — in both developed and developing countries — has often been an important consideration in influencing production and use of potatoes. Expanding output of potatoes can contribute to efforts to alleviate food shortages, improve rural incomes, and reduce poverty in developing countries — particularly in South Asia where poverty is highly concentrated.     

不同农药加"丝润"防治茶小绿叶蝉试验初报

"丝润"是农业部推广的新一代有机助剂,具有优异的润湿性能,能使药液在叶面迅速铺展,合理使用,可有效减少农药流失,减少农药使用量,降低农药残留。为了验证其     

常用封园药剂对茶橙瘿螨和假眼小绿叶蝉防治效果试验初报

在杭州茶区,通过45%晶体石硫合剂9、9%绿颖矿物油3、0%机油(石硫微乳剂为封园药剂,开展对茶橙瘿螨和假眼小绿叶蝉控害效果的试验,结果表明,三种封园药剂对茶橙瘿螨有较好的控害效果,对假眼小绿叶蝉控害效果则差异较大。