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101.
Before-After Control Impact (BACI) sampling designsare commonly used in environmental impact assessmentand are considered the most effective for detectingchanges due to anthropogenic disturbances. Thesedesigns handle local spatial variability throughrandomized placement of samples into a treatmentstratum and a control stratum. When a contaminantdisperses with distance from a point source it issuggested that a gradient design will be moresensitive to change than randomized placement ofsamples. This requires allocating samples according todistance, rather than by random placement withinrandomly placed blocks. In this paper gradient versusrandom sampling designs were compared using data froman oil field in the North Sea. The gradient samplingdesign was more powerful than a randomized CI sampling design.  相似文献   
102.
Over a period of 25 months, all antenatal patients were offered a detailed ultrasound scan at 18–20 weeks' gestation. The lateral cerebral ventricles were scanned for the presence of choroid plexus cysts. Fifty-one patients found to have choroid plexus cysts were offered amniocentesis to exclude chromosomal abnormalities. One pregnancy, in which the only abnormality found was bilateral choroid plexus cysts, was terminated after trisomy 18 was detected on amniocentesis at 19 weeks. The other 50 pregnancies had normal fetal outcomes. The significance of the isolated finding of choroid plexus cysts is reviewed.  相似文献   
103.
2267 singleton fetuses who had one ultrasound examination between 15 and 21 weeks' gestation were prospectively evaluated for echogenic small bowel. Thirty-two cases of echogenic small bowel were detected—a prevalence of 1·4 per cent. Echogenic fetal small bowel was divided into two grades: grade 1, where the small bowel was more echogenic than the liver; and grade 2, where the small bowel had the echogenicity of bone. In contrast to 19/23 fetuses with grade 1 small bowel echogenicity, only 2/9 fetuses with grade 2 echogenic bowel had a normal pregnancy outcome (Fisher's exact test; P⩽0·01). Complications associated with second-trimester echogenic small bowel included in utero cytomegalovirus infection, second-trimester growth restriction, intrauterine fetal demise, and chromosomal abnormalities. Second-trimester fetal echogenic small bowel is associated with an increased risk of an adverse outcome. The prevalence of perinatal and neonatal complications is significantly greater when small bowel echogenicity approaches that of bone.  相似文献   
104.
This study explores the preparedness of residents livingin a rural community in Victoria, Australia, for wildfires, and the factors influencing their preparedness. Overall, participants were well aware of wildfire risks and appeared well prepared for the event of a fire. However, residents involved in agriculture and with a long-standing association with the area appeared better prepared than were those on small properties and newcomers. Their social networks, previous experiences with wildfires and grassfires, and involvement with the local fire brigade influenced preparedness of long-term residents. Characteristics of agricultural communities, including a culture of self-reliance, experience with fires as part of farming, and social cohesion, appeared to contribute to wildfire preparedness within this community. Included are recommendations encouraging preparedness for wildfires.  相似文献   
105.
Alpha-male paternity in elephant seals   总被引:3,自引:0,他引:3  
The aim of this study was to assess paternity of males that dominated mating in harems at northern (Mirounga angustirostris) and southern (M. leonina) elephant seal rookeries using DNA fingerprinting and microsatellite DNA analysis. Southern alpha males had greater reproductive success than most northern alphas at similar-sized harems. Comparison of the relatedness between pups within harems also suggested that fewer males achieved matings in the southern elephant seal population. This was consistent with behavioral observations that suggest greater competition for mates in northern elephant seal harems. Reproductive success was consistent with estimates of mating success in some cases, but lower than expected for some northern elephant seal alpha males. A lower reproductive success than predicted from mating behavior may arise from a variety of factors including sperm competition, male sperm depletion from frequent mating, or reduced fertility. The alternatives are discussed in the context of environmental and historical factors. Received: 17 August 1998 / Received in revised form: 28 March 1999 / Accepted: 30 May 1999  相似文献   
106.
Analysis of the biological traits (e.g., feeding mode and size) that control how organisms interact with their environment has been used to identify environmental drivers of, or impacts on, species and to explain the importance of biodiversity loss. Biological trait analysis (BTA) could also be used within risk-assessment frameworks or in conservation planning if one understands the groups of traits that predict the sensitivity of habitats or communities to specific human activities. Deriving sensitivities from BTA should extend sensitivity predictions to a variety of habitats, especially those in which it would be difficult to conduct experiments (e.g., due to depth or risk to human life) and to scales beyond the norm of most experiments. We used data on epibenthos, collected via video along transects at 27 sites in a relatively pristine region of the seafloor, to determine scales of natural spatial variability of derived sensitivities and the degree to which predictions of sensitivity differed among 3 stressors (extraction of species, sedimentation, and suspended sediments) or were affected by underlying community compositions. We used 3 metrics (weighted abundance, abundance of highly sensitive species, and number of highly sensitive species) to derive sensitivity to these stressors and simulated the ability of these metrics to detect a range of stressor intensities. Regardless of spatial patterns of sensitivities across the sampled area, BTA distinguished differences in sensitivity to different stressors. The BTA also successfully separated differences in community composition from differences in sensitivity to stressors. Conversely, the 3 metrics differed widely in their ability to detect simulated impacts and likely reflect underlying ecological processes, suggesting that use of multiple metrics would be informative for spatial planning and allocating conservation priorities. Our results suggest BTA could be used as a first step in strategic prioritization of protected areas and as an underlying layer for spatial planning.  相似文献   
107.
Environmental Science and Pollution Research - The growth of two species of macrophytes (Lemna minor and Salvinia auriculata) under the effect of a mixture of amoxicillin, caffeine, carbamazepine,...  相似文献   
108.
Interactions between humans and wildlife resulting in negative impacts are among the most pressing conservation challenges globally. In regions of smallholder livestock and crop production, interactions with wildlife can compromise human well-being and motivate negative sentiment and retaliation toward wildlife, undermining conservation goals. Although impacts may be unavoidable when human and wildlife land use overlap, scant large-scale human data exist quantifying the direct costs of wildlife to livelihoods. In a landscape of global importance for wildlife conservation in southern Africa, we quantified costs for people living with wildlife through a fundamental measure of human well-being, food security, and we tested whether existing livelihood strategies buffer certain households against crop depredation by wildlife, predominantly elephants. To do this, we estimated Bayesian multilevel statistical models based on multicounty household data (n = 711) and interpreted model results in the context of spatial data from participatory land-use mapping. Reported crop depredation by wildlife was widespread. Over half of the sample households were affected and household food security was reduced significantly (odds ratio 0.37 [0.22, 0.63]). The most food insecure households relied on gathered food sources and welfare programs. In the event of crop depredation by wildlife, these 2 livelihood sources buffered or reduced harmful effects of depredation. The presence of buffering strategies suggests a targeted compensation strategy could benefit the region's most vulnerable people. Such strategies should be combined with dynamic and spatially explicit land-use planning that may reduce the frequency of negative human–wildlife impacts. Quantifying and mitigating the human costs from wildlife are necessary steps in working toward human–wildlife coexistence.  相似文献   
109.
Despite the professed concern of many governments, businesses and individuals – and the recent publication of another alarming report from the IPCC – inaction on climate change remains a significant concern. For many, the problem is rooted in a neoliberal account of social change. Neoliberal environmentalism is the dominant approach to environmental issues but it is often blamed for the continuing failure of climate change policy in general and behaviour change initiatives in particular. This paper explores the dynamics of this dominant discourse through an examination of environmentalism in the large “green” corporation. Specifically, it uses discourse analysis to investigate so-called “climate champion” schemes and considers examples of resistance to the dominant neoliberal discourse. The paper finds that many of the champions did resist the basic components of neoliberal environmentalism. They challenged the principles of self-interest, self-rule and incremental change, and they talked about the possibility of enforced action. However, this resistance was limited in a number of different ways. The paper suggests that the workplace does play a role in restricting resistance but that there are more fundamental issues that need to be addressed if we hope to pursue an alternative approach to environmental problems such as climate change.  相似文献   
110.
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