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151.
The toxicity and bioavailability of metals were assessed to verify the efficiency of a new chemical leaching process (METIX-AC) to minimize the risk of metals found in municipal sewage sludge. For this purpose, sludge samples were spiked with cadmium, copper and/or zinc before being treated using METIX-AC. The sludge decontamination resulted in a removal of spiked metals (79-89%), in a decrease of the more labile fractions, and in a corresponding increase of the residual fraction. The toxicity observed after exposure of two plant species, barley (Hordeum vulgare) and ryegrass (Lolium perenne), and a terrestrial invertebrate, Eisenia andrei, to sludge-soil mixtures, disappeared after treatment, although the adverse effects were minor before treatment. The sludge treatment also significantly decreased the bioaccumulation of cadmium, copper, and zinc in the exposed species. For cadmium, maximum tissue concentrations of 0.45+/-0.08 mg/kg in barley, 0.79+/-0.27 mg/kg in ryegrass, and 21.82+/-1.85 mg/kg in earthworm exposed to sludge before treatment decreased after treatment to values similar to those observed with negative controls.  相似文献   
152.
The Bathymodiolinae are pervasive in reducing environments in the deep sea, yet data on post-larval and juvenile development and on the process of symbiont acquisition remain elusive. To understand how these opportunistic metazoans survive in ephemeral reducing habitats, individuals of the small bathymodiolin, Idas modiolaeformis, were examined histologically to trace their reproductive development, and with fluorescence and transmission electron microscopy to identify patterns of infection by their environmentally acquired bacterial symbionts. A size series of these mussels was retrieved from larval colonisation devices containing vegetative substrates, deployed for 51 weeks (November 2006–2007) in the central ‘Pockmarks’ region (site 2A) of the Nile deep-sea fan in the eastern Mediterranean (NDSF), a zone where methane seepage can occur (N 32° 31.97, E 30° 21.18, 1,693 m deep). Developmental patterns of germ cell migration, size at first maturity, and symbiont acquisition and localisation are presented for the post-larva to adult transition. The smallest mature adult was a male with shell length (SL) 2.35 mm. All larger individuals in the series were male (maximum SL 6.54 mm). Based on the absence of bacterial signals, plantigrades were asymbiotic, indicating strict heterotrophy in larvae and early post-larvae. During the early stages of dissoconch deposition, extracellular symbiont infection was non-specific. This was followed by increasing specificity on non-ciliated gill epithelia in adults. These observations on early development in I. modiolaeformis represent evolutionary adaptations to their ephemeral, reducing habitats.  相似文献   
153.
RECOTOX is a cross-cutting initiative promoting an integrated research to respond to the challenges of monitoring, understanding, and mitigating environmental and health impacts of pesticides in agroecosystems. The added value of RECOTOX is to develop a common culture around spatial ecotoxicology including the whole chain of pressure-exposure-impact, while strengthening an integrated network of in natura specifically equipped sites. In particular, it promotes transversal approaches at relevant socioecological system scales, to capitalize knowledge, expertise, and ongoing research in ecotoxicology and, to a lesser extent, environmental toxicology. Thus, it will open existing research infrastructures in environmental sciences to research programs in ecotoxicology of pesticides.  相似文献   
154.
Slips contribute to 12% of occupational accidents. A slip resistant floor is a mean to prevent slipping accidents occurring in workshops. Floor slip resistance is often evaluated by measuring a friction index, proportional to the force opposing slipping of a reference elastomer on the floor surface under test. When implementing a portable appliance, slip resistance measurements carried out on lubricated floors were not stabilized. The authors advanced the hypothesis of oil impregnating the elastomer. A new elastomer suited to in-situ measurement has been developed to achieve stable measuring conditions. This study highlights the fact that the nature and characteristics of a reference elastomer must be specified when slip resistance measurements are carried out.  相似文献   
155.
The high species diversity of some ecosystems like tropical rainforests goes in pair with the scarcity of data for most species. This hinders the development of models that require enough data for fitting. The solution commonly adopted by modellers consists in grouping species to form more sizeable data sets. Classical methods for grouping species such as hierarchical cluster analysis do not take account of the variability of the species characteristics used for clustering. In this study a clustering method based on aggregation theory is presented. It takes account of the variability of species characteristics by searching for the grouping that minimizes the quadratic error (square bias plus variance) of some model’s prediction. This method allows one to check whether the gain in variance brought by data pooling compensate for the bias that it introduces. This method was applied to a data set on 94 tree species in a tropical rainforest in French Guiana, using a Usher matrix model to predict species dynamics. An optimal trade-off between bias and variance was found when grouping species. Grouping species appeared to decrease the quadratic error, except when the number of groups was very small. This clustering method yielded species groups similar to those of the hierarchical cluster analysis using Ward’s method when variance was small, that is when the number of groups was small.  相似文献   
156.
157.
Ultrasonography in a female fetus revealed cystic cervical hygroma, severe micrognathia, and vertebral and upper limb anomalies suggestive of cerebro-costo-mandibular syndrome (CCMS) which was diagnosed ultrasonographically at 16 weeks' gestation. The father is affected and presents with a Pierre Robin sequence, short stature and typical costovertebral anomalies. CCMS is a rare and severe disorder. The high frequency of sporadic cases, vertical transmission, and the excess of sibs affected via horizontal transmission suggest dominant autosomal mutation with possible germinal mosaicism. The vertical familial case detailed in the present report is a reminder of the high risk when one parent or one sibling is affected and the extreme variability of phenotype and costal ossification. Early prenatal ultrasound diagnosis is possible in a severely affected fetus. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   
158.
Despite the economic importance of oysters due to the high aquaculture production of several species, the current knowledge of oyster phylogeny and systematics is still fragmentary. In Europe, Ostrea edulis, the European flat oyster, and Ostreola stentina, the Provence oyster or dwarf oyster, are both present along the European and African, Atlantic and Mediterranean, coasts. In order to document the relationship not only between O. stentina and O. edulis, but also with the other Ostrea and Ostreola species, we performed a sequence analysis of the 16S mitochondrial fragment (16S rDNA: the large subunit rRNA-coding gene) and the COI fragment (COI: cytochrome oxidase subunit I). Oysters were sampled from populations in Portugal (two populations), Tunisia (two populations) and Morocco (one population), identified as O. stentina on the basis of shell morphological characters. Our data supported a high degree of differentiation between O. stentina and O. edulis and a close relationship between O. stentina and both Ostrea aupouria (from New Zealand) and Ostreola equestris (from Mexico Gulf/Atlantic). The status of this geographic disjunction between these closely related species is discussed. Furthermore, although identified in a separate genus Ostreola by Harry (Veliger 28:121–158, 1985), our molecular data on O. stentina, together with those available for the other two putative congeneric species, O. equestris and Ostreola conchaphila, would favour incorporation of Ostreola in Ostrea. Finally, a PCR-RFLP approach allowed the rapid identification of O. edulis and O. stentina.  相似文献   
159.
欧洲公园联盟 ( EUROPARC)制定了保护区可持续旅游的欧洲宪章 ,来促进完善的公园管理 .认证 的一个主要条件是保护区应具有一个经与当地的代表旅游、资源保护区和社区利益的利害攸 关者协商而精心制定的可持续旅游战略和行动计划 . 本文阐明了宪章制定的背景和一些有关 的问题及教训 .  相似文献   
160.
欧洲公园联盟 ( EUROPARC)制定了保护区可持续旅游的欧洲宪章 ,来促进完善的公园管理 .认证 的一个主要条件是保护区应具有一个经与当地的代表旅游、资源保护区和社区利益的利害攸 关者协商而精心制定的可持续旅游战略和行动计划 . 本文阐明了宪章制定的背景和一些有关 的问题及教训 .  相似文献   
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