Effect of microbial seeding of crude oil in seawater in a model system

The adding of a mixed culture of marine hydrocarbon-degrading bacteria to petroleum polluted seawater did not increase the hydrocarbon degradation capability of the water. All the strains of the mixed culture disappeared from the dominant microflora while the autochthonous bacteria showed a capacity for adaptation to petroleum degradation about four days after the oil spill. This confirms the advantage of natural bacterial communities. The oil spilled on the sea surface evolved very quickly under the influence of abiotic factors such as sunlight. Aromatic petroleum fractions were oxidized and polymerized. This chemical evolution causes a drastic decrease of the biodegradability of crude oil.     

经济发展成本分析:可持续发展经济学的理论基础

可持续发展战略存在着理论与实践上的严重反差，其主要原因是可持续发展经济缺乏统一的理论基础，本文通过对经济学不同流派关于可持续发展问题研究的评析，认为可持续发展经济学需要建立一个统一的理论基础，并提出经济发展成本分析是可持续发展经济学的理论基础，围绕这一理论基础对可持续发展的概念进行了重新界定，并主张要把制度的激励与约束以及政策的引导纳入可持续发展经济途径研究的视野之中。     

Importance of physical and biological settlement cues used at different spatial scales by the larvae of Semibalanus balanoides

The settling cues used by larvae of Semibalanus balanoides (L.) were examined at large (1 m), medium (1 mm), and small (<300 m) spatial scales, corresponding roughly to choices made during broad and close exploration and final inspection within the settling zone. The experiments were carried out at two locations in Canada in May and June 1984. Samples of substratum surfaces from above (n=87 sites unselected by cyprids) and below (n=84 sites selected by cyprids) the upper limit of the barnacle zone were characterized according to 13 quantitative and semi-quantitative variables (diatom cover, macroalgae, detritus) using scanning electron microscopy (SEM). The data were analysed using a stepwise logistic regression. At the large scale, the presence of an alga (Urospora wormskjoldii Mertens) in the upper uncolonized zone and a diatom (Achnantes parvula Kützing) within the settling zone are potential settlement cues. At the medium scale in the settling zone, larvae select clean sites, devoid of detritus and diatoms or on which detrital matter, when present, is of finer texture than on the unchosen sites within the settling zone. At the smallest scale (<300 m, equal to the average maximum width of the larvae), we tested the hypothesis that the larva seeks optimal microheterogeneity (presumably providing good adhesion). Microheterogeneity of the surface was measured immediately under the larva, around the settling organs, the antennules. Our results show that such surface microheterogeneity is significantly greater and the vertical center of gravity of the surface significantly lower on the sites selected by the cyprids than on the unselected contiguous sites. Fractal measurements carried out on selected and contiguous unselected surfaces indicate that larvae discriminate microheterogeneity levels below a step length of 35 m, a value approximately the size of the diameter of the antennular discs (40 m), which are used to explore the substratum and attach.Contribution to the programme of GIROQ (Groupe interuniversitaire de recherches océanographiques du Québec)     

Hormetic protection of Drosophila melanogaster middle-aged male flies from heat stress by mildly stressing them at young age

Previous studies have shown that exposing flies to hypergravity (3g or 5g) for the first 2 weeks of adult life slightly increases longevity of male flies and survival time at 37°C for both sexes, and delays an age-linked behavioral change. The present experiment tested whether the hypergravity could also protect flies from four successive deleterious non-lethal heat shocks at 4 and 5 weeks of age. Males that lived in hypergravity for the first 2 weeks of adult life lived slightly longer (ca. +15% or 1.2 day) after heat shocks (30 min or 45 min at 37°C) than flies that always lived at 1g, but this positive effect of hypergravity was not observed in females. Therefore, hypergravity exposure at young age can help the male flies recovering from a heat shock at older ages.     

Specialization of the entomopathogenic nematode Steinernema scapterisci with its mutualistic Xenorhabdus symbiont

The level of specialization of the entomopathogenic nematode Steinernema scapterisci with its native Xenorhabdus symbiont was investigated by testing (1) the influence of non-native bacterial strains on nematode fitness within an insect-host (Galleria mellonella) and (2) specificity of the association between the nematode infective juveniles and non-native bacteria. All non-native Xenorhabdus spp. or Photorhabdus spp. strains tested were mutualistically associated with other entomopathogenic nematodes in nature. We showed that most of the Xenorhabdus spp. strains tested led to an insignificant difference of the nematode's fitness compared to the one obtained with the native bacterium. Conversely, Photorhabdus spp. strains almost entirely abolished nematode reproduction. The phylogenetic analysis of bacterial strains tested, showed that there was a negative correlation between S. scapterisci's reproduction rate with a bacterial strain and the genetic distance of this bacterial strain from the native one. We also showed that the native bacterium was the only one which was transmitted by S. scapterisci's infective juveniles. All these results, suggested a specialization between S. scapterisci and its native Xenorhabdus. As the same phenomenon was already demonstrated in the association between S. carpocapsae and X. nematophila, specialization between partners would not be an exception in entomopathogenic nematode-bacteria interactions. Nevertheless, S. scapterisci showed a dramatically higher compatibility with non-native Xenorhabdus spp. strains than did S. carpocapsae, suggesting differences in the co-evolutionary processes between nematodes and bacteria in these two model systems.Table 1 List of the bacterial strains, native nematode species with their geographical origin, accession numbers of bacterial 16S rDNA partial sequences and number of combination experiments for each bacterium tested

Foraging habitats of the seabird community of Europa Island (Mozambique Channel)

We investigated the foraging habitats of the winter breeding community of tropical seabirds from Europa Island (Mozambique Channel) in September 2003. We focused our study on the dominant species of this austral community, the sooty tern (Sterna fuscata), the red-footed booby (Sula sula), and the frigatebirds, including the great (Fregata minor) and the lesser frigatebirds (F. ariel). We considered the at-sea distribution and abundance of these species in relation to chlorophyll concentration, sea-surface temperatures, sea-surface height anomalies, depth of the thermocline, distance to the colony, and presence of surface marine predators, flying fishes and other seabirds. Although the marine environment where seabirds foraged was oligotrophic, it presents the best feeding opportunities for seabirds for the area in winter. Our study demonstrates that the winter-breeding seabird species of Europa Island tend to forage in productive waters in association with other marine predators when possible. Sooty terns and frigatebirds were widely distributed in the whole study area, whereas red-footed boobies were not found farther than 160 km from their colonies and were associated with relatively productive waters. Sooty terns and red-footed boobies were aggregated where flying fishes were abundant. The presence of other marine predators was associated with larger multispecies feeding flocks than when no association occurred. Sooty terns, which are numerically dominant at Europa and adopted network foraging, seem to be catalysts of feeding events, and represented a good target for the other foraging species, especially frigatebirds. However, when possible, frigatebirds favour association with flocks of red-footed boobies.Communicated by S.A. Poulet, Roscoff     

Observations sur le développement larvaire de Nyctiphanes couchii (Crustacea: Euphausiacea) au laboratoire

Larvae of Nyctiphanes couchii (Bell) were reared in the laboratory from the second and third calyptopis stages; they were fed animal, algal and mixed diets. Data are presented on larval morphology, growth and moulting rates. It is demonstrated that N. couchii is capable of filter-feeding and of capturing prey from the calyptopis phase onwards. The influence of diet on larval development is discussed: algal diets induce a slower growth rate than that achieved by feeding with Artemia salina nauplii alone, and increase the length of intermoult periods and of ontogenesis. A limited supply of A. salina nauplii has similar effects.     

北京市危险化学品安全生产技术支撑体系建设

1引言 近年来,在北京市委、市政府的领导下,各职能部门的协同努力下,北京市危险化学品安全生产工作取得了显著成绩,制定了一系列危险化学品安全生产管理规范,开展了危险化学品从业单位安全质量标准化活动,进一步提高了从业单位的安全生产管理水平,我市危险化学品安全生产状况总体趋向好转.     

以质量管理体系为基础建立实施一体化企业管理体系

结合镇海炼化实施一体化管理体系的实践,阐述了实施一体化体系的必要性和可行性,介绍了一体化管理体系的基本框架,以及体系建立和实施过程中的经验和体会.     

中心商业区环境安全管理与控制

城市中心商业区环境安全的管理与控制是城市诸多问题中的热点.通过分析中心商业区的环境空气质量和环境噪声、防火防爆设施及应急装备、人流车流秩序、公共卫生系统,提出了在城市中心商业区环境安全的管理与控制中应执行的相关标准,设立了相关部门和管理措施.对中心商业区环境安全控制的规制化具有一定积极意义.