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151.
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153.
Julie R. Marentette Grace Wang Stephanie Tong Natalie M. Sopinka Matthew D. Taves Marten A. Koops Sigal Balshine 《Behavioral ecology and sociobiology》2011,65(12):2239-2249
Activity levels are modulated by trade-offs between reducing predation risk and the need to move in order to find food or
mates. Because these trade-offs affect males and females differently, many species show sex-specific movement, dispersal patterns,
and spatial navigation capacities, with the sex that gains the most from territory ownership often dispersing less. Unlike
mammals and birds, sex differences in movement among fishes remain poorly studied, and the connections between tests of movement
propensity in the laboratory and in the field are rarely made. Here, we examine the differences in movement between male and
female round goby (Neogobius melanostomus) in both laboratory and field settings. This fish species is invasive in North America and currently undergoing further range
expansions. In the laboratory, round goby males were more active and explored a novel environment more readily than did females.
A large-scale mark–recapture study in Lake Ontario over two years revealed that males moved more than females between years,
but there were no within-year sex differences. Thus, round goby display male-biased movement patterns, providing a comparison
point to dispersal patterns in other taxa. Understanding sex-specific movement of round goby in the field will also help predict
dispersal and population dynamics, both in areas where round goby have already become established and where they are continuing
to invade. 相似文献
154.
Geographical variations in animal characters are one of the main subjects for study in macroecology. Variation with latitude
has received special interest. Articulated brachiopods are possibly the commonest macrofossil with large variations in size
of taxa through the fossil record. Here, we investigate trends in size of the 3 main orders of articulated brachiopod with
latitude and depth. Data were insufficient to identify patterns in Thecideida (a micromorph taxon only recorded from low latitudes).
Rhynchonellida had no clear trends in size with latitude or depth. Terebratulida exhibited hemispheric differences in size
relations, with increasing length of species towards the pole in the south and no significant trend in the north. Tropical
species were small (<20 mm length between 10°N and 10°S), and the largest species were found between 30° and 60° latitude
in both hemispheres. There were no articulated brachiopods recorded from the high arctic, and support for a continuous trend
in size with latitude was small or absent. In Terebratulida, there was a significant decrease in species length with depth
of 1.7 mm per 100 m depth increase. These trends could be explained by competition for space and reduced availability of habitat
with progressive depth beyond the continental shelf. 相似文献
155.
Deborah Keeley Shane TurnerPeter Harper 《Journal of Loss Prevention in the Process Industries》2011,24(3):237-241
The UK Health and Safety Executive (HSE) requires failure rate data for the assessment of COMAH safety reports and in the implementation of its statutory functions relating to land use planning in the vicinity of major hazard sites. Many of the existing failure rates used by HSE were derived over 20 years ago, but have been subject to periodic review to ensure that they remain appropriate for modern planning enquiries or quantified risk assessments. HSE needs to be assured that its sources of data and their application continue to be fit to support its statutory duties.HSE has implemented a programme of work to be carried out by the Health and Safety Laboratory (HSL). This includes the development and maintenance of a single source of quality assured failure rate data, ideally accessible from the Internet, bringing together and updating existing failure rate data sources and reviewing new sources not previously available to HSE.A review of HSE’s current failure rate values is being carried out and this will be used to generate a single source of publically available failure rate data for use by both HSE and the public. This would help industry and HSE move toward a common position or understanding on failure rates. It would also help ensure that HSE professional advice is defensible and transparent.This paper will detail the progress made to date on the programme of work. It will also discuss the issues that arise as a consequence of changing failure rates and how HSE deals with these issues. 相似文献
156.
Compared with groundwater pollution episodes of a point-source nature, nonpoint-source contamination makes for particularly
difficult policy design. This is especially true in the context of a mixed land-use aquifer, where the same pollutant may
derive from various human land-use activities and in different concentrations. To data, the emprirical literature attempting
to estimate the relative loadings of pollutants from alternative land uses is rather sparse. Yet this information is vital
to a variety of numerical computer models used to predict likelihood of groundwater contamination, and the statistical results
are useful in their own right for regional policy formation. Regression analysis is applied to estimate loadings of nitrate
and sodium from various land uses. The model is then used to illustrate how well-intended local groundwater protection policies
that fail to recognize land-use substitution and cross-pollutant effects may be misdirected. 相似文献
157.
Grace H. Wever 《环境质量管理》1995,4(3):75-91
The Great Lakes region has a wealth of natural resources, including a system of five large lakes with 20 percent of the world's surface freshwater. A century and a half of municipal, industrial, and agricultural expansion has created a variety of environmental pressures. A 1972 landmark agreement between the United States and Canada committed both countries to an ecosystem-based approach to management and a strategy of virtually eliminating toxic chemical inputs. Over the past few decades, significant investments were made to address the region's environmental health. More recent strategies, however, were developed without adequate consideration of their economic and social impacts. Using the quality-based framework described in Part I of this article, this case study shows that the region has moved from crisis management to a more proactive, anticipatory approach. 相似文献
158.
Joyce C. Harper Dagan Wells Wirawit Piyamongkol Patrick Abou-Sleiman Angela Apessos Antonis Ioulianos Mary Davis Alpesh Doshi Paul Serhal Massimo Ranieri Charles Rodeck Joy D. A. Delhanty 《黑龙江环境通报》2002,22(6):525-533
We report our experience of 14 preimplantation genetic diagnosis (PGD) cycles in eight couples carrying five different single gene disorders, during the last 18 months. Diagnoses were performed for myotonic dystrophy (DM), cystic fibrosis (CF) [ΔF508 and exon 4 (621+1 G>T)], fragile X and CF simultaneously, and two disorders for which PGD had not been previously attempted, namely neurofibromatosis type 2 (NF2) and Crouzon syndrome. Diagnoses for single gene disorders were carried out on ideally two blastomeres biopsied from Day 3 embryos. A highly polymorphic marker was included in each diagnosis to control against contamination. For the dominant disorders, where possible, linked polymorphisms provided an additional means of determining the genotype of the embryo hence reducing the risk of misdiagnosis due to allele dropout (ADO). Multiplex fluorescent polymerase chain reaction (F-PCR) was used in all cases, followed by fragment analysis and/or single-stranded conformation polymorphism (SSCP) for genotyping. Embryo transfer was performed in 13 cycles resulting in one biochemical pregnancy for CF, three normal deliveries (a twin and a singleton) and one early miscarriage for DM and a singleton for Crouzon syndrome. In each case the untransferred embryos were used to confirm the diagnoses performed on the biopsied cells. The results were concordant in all cases. The inclusion of a polymorphic marker allowed the detection of extraneous DNA contamination in two cells from one case. Knowing the genotype of the contaminating DNA allowed its origin to be traced. All five pregnancies were obtained from embryos in which two blastomeres were biopsied for the diagnosis. Our data demonstrate the successful strategy of using multiplex PCR to simultaneously amplify the mutation site and a polymorphic locus, fluorescent PCR technology to achieve greater sensitivity, and two-cell biopsy to increase the efficiency and success of diagnoses. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
159.
R.P. Grace 《Resources Policy》1979,5(1):26-33
This article draws attention to a policy which has largely been ignored by the UK government. In certain instances, taxation may be used to correct defects caused by environmental pollution, through the price mechanism. Frequently, social costs are not included in the price goods with the result that distortion occurs in the optimum allocation of resources. Taxes can be used to adjust prices automatically and efficiently, thereby correcting the misallocation. The paper first introduces this concept theoretically, as it applies to waste disposal and recyling, and then considers how this theory might in practice apply to the UK. 相似文献
160.
Farmers attempting to subsist in tropical uplands often rely upon unsustainable resource use practices that lead to soil erosion, declining crop yields, and a loss of soil productivity capacity. Other uses of tropical uplands, including logging and conversion of forest to rangelands, have similar results. The undesirable effects of these actions are felt on-site, at the watershed level, and even nationally. Ecological cause-effect relationships are poorly understood, and few examples exist of the successful integration of ecological knowledge with upland development. It is hypothesized that recent results of ecological research could be applied to uplands management so that stable sustainable systems of human use may be established. A second hypothesis is that statistically reliable data can be obtained from experiments in upland situations, although natural variations of soils, weather, and vegetation are great. To test these hypotheses, research involving multinational collaboration among American and Southeast Asian scientists has begun. The objective of the work is to provide credible quantitative information to help policy and decision makers and resident farmers to plan and implement improved practices based on ecological principles.Some findings to date include:
相似文献
1. | Ecological principles are difficult to relate to the practical context of upland agroecosystems. Indeed, the null hypothesis is necessary for planning experiments and demonstrations. |
2. | The signal-to-noise ratio in these field experiments is low, and the detection of changes due to human intervention in soil erosion, nutrient movement, and plant productivity is difficult. |
3. | Obstacles to field research in developing countries include logistic, cultural, political, and institutional factors. It is essential that local land managers participate from the start with scientific researchers in designing experiments. |
4. | Planned collaboration among academic and government scientists facilitates design of relevant research and the implementation of results. |
5. | The idea of ecologically based management has been well received by researchers and government officials in Asia. There is little argument with the logic of the approach. |
6. | Pressures for quick responses to urgent problems in the uplands conflict with the need for careful, long-term, statistically valid scientific research. |
7. | Ecological principles are vaguely understood and poorly articulated in the scientific literature. The transfer and application of ecological science to the developing world would be enhanced by clearer statements of principles. |