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571.
Blood lead concentration is still most commonly used to assess the degree of exposure to environmental lead. However, blood lead levels are relatively transient and so tissues such as hair which store lead over longer periods need to be explored as bioindicators of lead toxicity. The results of such an investigation into hair are presented. These results indicate that there are significant differences in scalp-hair levels between the African, East Indian and Chinese racial groups in the multiracial adult population of Trinidad, West Indies. However, no significant differences were found for the pubic hair levels among the three races. The percentage of sulphur or the carbon: sulphur ratios in scalp hair did not influence the scalp-hair lead levels in the general population, although a significant difference in the carbon:sulphur ratios was observed between the African and East Indian racial groups. 相似文献
572.
Several works on public perception of bathing area quality state that litter is one of the top concerns of users. Litter was also considered the top concern of bathing users regarding Bathing Area (BA) quality in S?o Miguel (Azores). This fact highly justifies the need to evaluate BA in this perspective. During 2009 summer 11 bathing areas, covering all the proposed BA typologies in S?o Miguel Island, were assessed and rated according to litter. The methodology was based on the EA/Protocol (Environmental Agency (UK)/National Aquatic Litter Group 2000). BA were graded from A to D (very good, good, fair and poor) on several litter categories: sewage related debris, gross litter, general litter, harmful litter, accumulations, oil or similar and faeces. Transects were sampled at 7 (o??clock) p.m. on sunny Sundays to achieve extreme situations. From the bathing areas assessed 4 were rated B (Good) and 7 rated C (Fair). During the same period the users perception regarding litter was assessed. Data obtained was related to bathing areas Scenic Evaluation Index (D) value, establishing a 5-class evaluation system. Some interactions between these factors (litter, BA typologies, public perception and scenic value) were analyzed and discussed. Scenic value doesn??t seem to affect users behavior regarding litter, however seems to affect the perception of users. Some of the bathing areas typologies seem to be more affected by litter, especially Urban and Semi-urban sandy beaches. BA cleaning processes and the relation of users with the area are the main reasons to this fact. 相似文献
573.
Species boundaries in the starfish genus Linckia 总被引:3,自引:0,他引:3
S. T. Williams 《Marine Biology》2000,136(1):137-148
The genetic basis for species boundaries in the starfish genus Linckia was examined using variation observed in 613 base pairs (bp) of sequence from the cytochrome oxidase I gene of mtDNA and
16 allozyme loci. Five groups within Linckia were clearly genetically differentiated; L. columbiae, L. bouvieri, two clades within L. guildingi, and one clade with two sub-clades consisting of both L. laevigata and L. multifora. Genetic divergence among these groups is consistent with interspecific variation. The two clades within L. guildingi suggest the presence of a cryptic, partially sympatric, species. Genetic divergence between these two clades implies that
they have been genetically distinct from each other for at least one million years. In contrast, genetic data suggest that
L. laevigata and L. multifora are a single species, despite the fact that live individuals can be distinguished by their colour and colour pattern, number
of madreporites and ratio of arm length to breadth. There are probably three closely related groups within the L. laevigata/L. multifora clade –L. multifora, and two groups in L. laevigata defined by biogeographic province. It is difficult to determine boundaries for these three entities, since genetic and morphological
differences are complicated by phenotypic differences arising from both environmental variation and population genetic structure.
The difficulties encountered in defining species boundaries in Linckia, particularly with respect to variation arising from the overlap of Indian and Pacific biogeographic provinces, may be a
general issue for many marine organisms from this region.
Received: 24 May 1999 / Accepted: 6 October 1999 相似文献
574.
Nemitz E. Flynn M. Williams P. I. Milford C. Theobald M. R. Blatter A. Gallagher M. W. Sutton M. A. 《Water, Air, & Soil Pollution: Focus》2001,1(5-6):189-202
A continuous relaxed eddy accumulation system ispresented for the automated measurement of surface/atmosphere exchange fluxes of atmospheric ammonia (NH3) at a single height. The new system features sampling by parallel plate denuder inlets, online chemical analysis using the conductivity cell of a commercially available NH3 analyzer and online flux calculation. The effective detection limit of the system for air concentrations is 0.2 g m-3 and it is estimated to resolve fluxes > ± 20 ng m-2 s-1, depending on the NH3 concentration and turbulence. The performance of the system was tested in two measurement campaigns above agricultural grassland, in which it was compared with a 3-point continuous gradient system. During the first campaign, after urea application of 47 kg N ha-1 in autumn, the REA system derived fluxes which were on average twice as large as the gradient fluxes, while concentrations agreed closely (on average within 4%). Possible reasons include differences in the footprint and an over-correction of the gradient flux in stable conditions. Due to wet and cold conditions, only 0.3% of the fertilizer N was volatilized as NH3 during the first week. Results from the deployment of an improved system are presented for a summer day, 6 days after fertilization with calcium ammonium nitrate. The agreement of both concentrations (on average within 13%) and fluxes (26%) was very encouraging and similar to the agreement found between two state-of-the-art gradient systems with online analysis. 相似文献
575.
Stone GS Henderson AK Davis SI Lewin M Shimizu I Krishnamurthy R Bisgard K Lee R Jumaan A Marziale E Bryant M Williams C Mason K Sirois M Hori M Chapman J Bowman DJ 《Disasters》2012,36(2):270-290
The 2005 hurricane season caused extensive damage and induced a mass migration of approximately 1.1 million people from southern Louisiana in the United States. Current and accurate estimates of population size and demographics and an assessment of the critical needs for public services were required to guide recovery efforts. Since forecasts using pre-hurricane data may produce inaccurate estimates of the post-hurricane population, a household survey in 18 hurricane-affected parishes was conducted to provide timely and credible information on the size of these populations, their demographics and their condition. This paper describes the methods used, the challenges encountered, and the key factors for successful implementation. This post-disaster survey was unique because it identified the needs of the people in the affected parishes and quantified the number of people with these needs. Consequently, this survey established new population and health indicator baselines that otherwise would have not been available to guide the relief and recovery efforts in southern Louisiana. 相似文献
576.
Rutta E Williams H Mwansasu A Mung'ong'o F Burke H Gongo R Veneranda R Qassim M 《Disasters》2005,29(4):291-309
This article describes the findings of a participatory assessment of Burundian and Rwandan refugees' perceptions of the quality of health services in camps in Ngara, Tanzania. Taking a beneficiary-centred approach, it examines a collaborative effort by several agencies to develop a generic field guide to analyse refugees' views of healthcare services. The objective was to gather information that would contribute to significant improvements in the care offered in the camps. Although the primary focus was on healthcare, several broader questions considered other general apprehensions that might influence the way refugees perceive their healthcare. Findings indicated that while refugees in Ngara were generally satisfied with the quality of healthcare provided and healthcare promotion activities, recognition of some key refugee concerns would assist healthcare providers in enhancing services. With increasing need for refugee community participation in evaluating humanitarian assistance, this assessment has relevance both in the context of Ngara and beyond. 相似文献
577.
578.
In response to the EU Landfill Directive and the challenge of mitigating climate change, the UK government (nationally and locally) must develop strategies and policies to reduce, recycle, compost and recover waste. Best practice services that yield high recycling rates, such as alternate weekly collections, are now largely mainstream in suitable areas. However, national recycling performance is short of what is needed; policy makers must look for innovative ways to meet challenging recycling targets.Increasingly, local authorities are using behaviour change interventions to encourage the public to recycle; these tend to be based on the premise that an individuals’ behaviour is predetermined by their values. In practice, this has led to a host of initiatives that attempt to change individuals’ behaviour without addressing situational barriers. In this paper, we argue that that a behaviour-centric approach has limited effectiveness. Using an analysis of the literature and studies that investigated recycling participation in the city of Portsmouth, we have identified three significant clusters that can facilitate effective recycling: infrastructure, service and behaviour (ISB). We present the ISB model - a tool that can be used by waste practitioners when planning interventions to maximise recycling to better understand the situation and context for behaviour. Analysis using the ISB model suggests that current best practice, “business as usual” interventions could realistically achieve a national recycling rate of 50%. If the UK is to move towards zero waste, policy makers must look “upstream” for interventions that change the situational landscape. 相似文献
579.
Costs and benefits of brood desertion in female kentish plovers,Charadrius alexandrinus 总被引:3,自引:0,他引:3
Female kentish plovers Charadrius alexandrinus typically desert their broods after the chicks hatch, i.e. 1–4 weeks before the chicks fledge or become independent. In this paper we investigate the costs and benefits of desertion for females. Desertion incurs a cost for females: following desertion chick survival in broods is lower (0.95 +- 0.02 day–1) than before the female deserts (0.98 +- 0.01 day–1). We investigated several possible causes for reduced brood survival by comparing characteristics of broods before and after desertion (controlling for differences in brood age). After desertion males increased the time they spent foraging and they tended to reduce time spent brooding chicks. Increased mortality of chicks may occur in deserted broods because following desertion (1) males spend less time alert in vigilance behaviour than before desertion, (2) they attend the chicks from greater distances, and (3) they show greater distraction display distances (in response to human intruders). Growth or development of chicks, measured by weight gain and tarsus length, was not different before and after desertion. Females gain two potential benefits from desertion: (1) they may remate and produce a second brood within the same breeding season or (2) they may enhance their probability of surviving to breed in a subsequent season. At least 27% of female kentish plovers that deserted remated and renested in the same season in this study. In contrast, we found no evidence that brood desertion increased the survival of females: there was no difference in local survival rate (return rate) for females deserting before or after 6 days brood age. These results clearly demonstrate that female kentish plovers that desert their offspring prior to fledging incur costs, but we suggest that there is a trade-off with the potential benefits gained by remating and making a second breeding attempt in the same season. 相似文献
580.
Effect of uranium on growth and reproduction of the marine amphipod Allorchestes compressa 总被引:1,自引:0,他引:1
Experiments on growth of the marine amphipod Allorchestes compressa Dana were carried out over four weeks, and both growth and reproduction were studied over three generations, each of which was exposed to uranium for approximately 10 wk. At 0.1 mg l-1 the uranium increased growth by 23%, as measured by the mean weight after 4 wk, and at 2 mg l-1 growth was reduced by 28% compared with the control. A. compressa accumulated uranium from sea water with a concentration factor of 10. There was no effect of uranium on the survival of amphipods or their progeny in the multiple-generation experiment, but the numbers of males, the sex ratio, and the respiration rate (measured on males only) at 1mg l-1 were significantly lower than the control. A. compressa is shown to be a convenient species for the study of toxic effects on growth and reproduction using multiple-generation experiments. 相似文献