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71.
We examine in detail trends from 1966 to 1990 and the fitting of statistical models to assess whether significant changes have taken place in casualty rates since local bus deregulation in 1986.The major source of data is the ‘Stats 19’ collated from police reports by the Department of Transport.The evidence indicates that no significant change in casualty rates for bus and coach occupants (defined as those killed or seriously injured) has occurred since local bus deregulation, although the previous trend of reduction in fatality rates has not been maintained.International comparisons have been made between Britain and a sample of other West European countries. Britain appears to have a higher occupant fatality rate. However, other countries′ data do not always include casualties to bus and coach occupants other than those in which vehicular collisions occur. Better comparative data is available for accidents involving buses and coaches with other road users, notably for Britain and Germany. These suggest that such accidents tend to reflect the national pattern of road casualty rates — for example, Germany has a higher level of collisions between buses and coaches, and other road vehicles, while Britain has a relatively high incidence of casualties involving pedestrians.Differences in accident rates between Britain and other European countries and the extent to which they reflect real differences, as distinct from those due to differences in recording of data, are evaluated, along with policy implications.  相似文献   
72.
The Swedish nationwide surveys of atmospheric heavy metal deposition in 1968/70 – 1995 using bryophytes (carpet-forming mosses) as monitors are reviewed. Considered are cadmium (Cd), copper (Cu), iron (Fe), lead (Pb), mercury (Hg), nickel (Ni), vanadium (V), and zinc (Zn). The close agreement between data obtained with deposition (precipitation) collectors and moss carpet analysis is documented briefly, as well as measures of quality control and assessment of reproducibility. Since 1968/70, the deposition rate of the heavy metals considered has declined gradually and evenly, particularly in the southern parts of the country, reflecting an improvement of general air quality due to decreasing dust emission from mainly industry and fossil fuel combustion in northern and western Europe. By far the greatest absolute decrease in deposition rate was measured in Fe, which is a main constituent of most man-generated dust particles. However, the greatest per cent decreases in deposition rates were measured for Pb. The Pb concentration of moss carpets in Sweden as a whole in 1995 was only 11% of the value in 1968/70. Corresponding figures for Fe was 20%, Cd 24%, Ni 28%, Hg 31%, V 43%, Zn 51%, and Cu 52%. For Zn the current deposition rate seems to approach a natural baseline, whereas deposition of the other seven elements are still decreasing according to the surveys of 1990 and 1995.  相似文献   
73.
Many government agencies and other organizations hold large tracts of surplus land. Some are investigating ways to lower expenses by selling the land or transferring management responsibility. There is no generally recognized process used to decide what land can be decommissioned and what future use would be best. This paper provides guidance for land‐use decisions in the form of a checklist. The checklist questions address both the socio‐economic resources and current land use in the region, and the ecological resources and suitability of the tract itself. The answers will clarify regional public needs and the economic and ecological values of the land.  相似文献   
74.
Biological rhythms are a result of interplay between endogenous clocks and the ambient light–dark (LD) cycle. Biological timing in resident polar organisms presents a conundrum because these experience distinct daily LD cycles for only a few weeks each year. We measured locomotor activity in reindeer, Rangifer tarandus platyrhynchus (SR, n = 5 and 6) and R. tarandus tarandus (NR, n = 6), ranging freely at 78 and 70°N, respectively, continuously throughout 1 year using data loggers. NR, but not SR, are gregarious which enabled us to examine the integrated effects of differences in social organisation and the photic environment at two different latitudes on the organisation of activity. In both sub-species, ultradian bouts of activity and inactivity alternated across the 24-h day throughout the year. This pattern was modified by the LD cycle in NR but barely at all in SR. Periodogram analysis revealed significant ultradian rhythmicity in both sub-species; the frequency of daily cycles of activity increased from three per day in winter to nearly five in summer. We conclude that this increase, and a concomitant increase in the level of daily activity, reflected the seasonal increase in the animals’ appetite and the quality of their forage. Secondly, the combination, most evident in SR, of a weak photic response, weak circadian mechanisms and a weak social synchronization reduces the constraints of biological timing in an environment which is effectively non-rhythmic most of the year and permits expression of the basic ultradian pattern of ruminant activity. Third, the weaker 24-h rhythmicity in SR compared to NR indicates a latitudinal decrease in circadian organization and photic responsiveness in Rangifer.  相似文献   
75.
Some physico-chemical properties and the concentrations of the metals Fe, Mn, Ni, Cd, Cr, Co, Cu, Pb, and Zn in water and sediments were examined from September 2011 to January 2012 in Bodo Creek, where oil spills have been recurrent. Temperature, pH, total dissolved solid, conductivity, salinity, dissolved oxygen, biological oxygen demand (BOD), chemical oxygen demand (COD), total hardness, sulfate, nitrate, and phosphate were determined in surface water. Particle size, total organic matter (TOM), and pH were also determined in the sediments. The parameters were within permissible limits except the mean values of BOD, COD, total hardness, and sulfate that exceeded levels permissible for domestic use. The sediments consisted mainly of sand, with TOM ranging from 0.2% to 5.5%. With the exception of cadmium that was below detection limit, metal levels (mg kg?1) in the sediments were 12 (Mn), 1070 (Fe), 10 (Cu), 10 (Zn), 5.3 (Cr), 1.1 (Pb), 1.0 (Ni), and 0.5 (Co) while in water they were 24, 98, 21, 6.9, 4.0, 0.6, 0.18, and 0.16, respectively. The latter were higher than World Health Organization recommended permissible levels for both surface and drinking water.  相似文献   
76.
Whitman County, Washington, USA, one of the largest wheat producing counties in the country, developed a land evaluation and site assessment system for evaluating proposed conversions of agricultural land to heavy commercial uses. The system uses soil potential indices to determine a land evaluation score and a nine-factor site assessment system to weigh suitability for development. Details on each of these are provided along with results for four sample sites.Scientific Paper no. 7165, College of Argiculture and Home Economics Research Paper, Washington State University, Pullman, Washington, project no. 0010.  相似文献   
77.
In recent decades, there has been an increasing emphasis on proactive efforts to conserve species being considered for listing under the U.S. Endangered Species Act (ESA) before they are listed (i.e., preemptive conservation). These efforts, which depend on voluntary actions by public and private land managers across the species’ range, aim to conserve species while avoiding regulatory costs associated with ESA listing. We collected data for a set of social, economic, environmental, and institutional factors that we hypothesized would influence voluntary decisions to promote or inhibit preemptive conservation of species under consideration for ESA listing. We used logistic regression to estimate the association of these factors with preemptive conservation outcomes based on data for a set of species that entered the ESA listing process and were either officially listed (n = 314) or preemptively conserved (n = 73) from 1996 to 2018. Factors significantly associated with precluded listing due to preemptive conservation included high baseline conservation status, low proportion of private land across the species’ range, small total range size, exposure to specific types of threats, and species’ range extending over several states. These results highlight strategies that can help improve conservation outcomes, such as allocating resources for imperiled species earlier in the listing process, addressing specific threats, and expanding incentives and coordination mechanisms for conservation on private lands.  相似文献   
78.
Despite widespread information on the incidence and biochemical effects of polychlorinated biphenyls (PCBs) in birds, field studies of effects on population processes are still scarce. This is particularly so in passerines. We therefore assessed breeding performance and post-fledging survival in dippers, Cinclus cinclus, breeding along the Afon Mule, a Welsh river where previous work indicated locally elevated PCB concentrations. We hypothesised that marked toxicological effects, including endocrine disruption, would be detectable as altered clutch-size, hatching success, nest success, brood-size, post-fledging survival or recruitment to the breeding population. Congener-specific analysis of PCBs in failed and deserted dipper eggs during 1990–93 revealed that geometric mean concentrations were four to 20 times higher along the Mule than elsewhere in Wales, UK. PCB signatures also varied highly significantly from other locations, with congeners 138, 153 and 180 dominant at the contaminated site, but 118 or 170 more frequent in eggs elsewhere. Subsequent analysis of surface runoff confirmed a small breaker's yard as a point source. Neither laying dates, clutch-sizes, brood-sizes, nest failure nor hatching failure along the contaminated Mule (n=46 breeding attempts and 218 eggs) differed significantly from dippers along adjacent reference rivers (n=82 breeding attempts and 315 eggs) or Welsh rivers as a whole (n=332 breeding attempts and 1534 eggs). Subsequent recaptures of breeding dippers ringed initially as nestlings were nearly identical between the Mule (7.7% of 182 nestlings), the reference set (7.5% of 323 nestlings) and all other Welsh rivers (7.3% of 2821 nestlings). These data illustrate the value of congener-specific analysis of bird's eggs in indicating local PCB sources. The data show also that PCBs can occur in dipper eggs at total concentrations of 0.49 (geometric mean)–1.29 (upper quartile) μg g−1 wet mass without effects on breeding performance and survival. These values are below those at which biochemical or reproductive effects on other passerines have been detected, but above current concentrations in any other population of European dippers for which PCB data are available. Population effects by PCBs on European dippers are therefore unlikely. Survivors from locally contaminated sites like that in our study might allow field assessments of second-generation effects on breeding performance in wild birds that have developed under PCB exposure.  相似文献   
79.
Effective ecological monitoring is imperative in a human-dominated world, as our ability to manage functioning ecosystems will depend on understanding biodiversity responses to anthropogenic impacts. Yet, most monitoring efforts have either been narrowly focused on particular sites, species and stressors — thus inadequately considering the cumulative effects of multiple, interacting impacts at scales of management relevance — or too unfocused to provide specific guidance. We propose a cumulative effects monitoring framework that integrates multi-scaled surveillance of trends in biodiversity and land cover with targeted evaluation of hypothesized drivers of change. The framework is grounded in a flexible conceptual model and uses monitoring to generate and test empirical models that relate the status of diverse taxonomic groups to the nature and extent of human “footprint” and other landscape attributes. An adaptive cycle of standardized sampling, model development, and model evaluation provides a means to learn about the system and guide management. Additional benefits of the framework include standardized data on status and trend for a wide variety of biodiversity elements, spatially explicit models for regional planning and scenario evaluation, and identification of knowledge gaps for complementary research. We describe efforts to implement the framework in Alberta, Canada, through the Alberta Biodiversity Monitoring Institute, and identify key challenges to be addressed.  相似文献   
80.
Larval defensive behaviour and eversible organ morphology were compared in the firefly species Luciola cruciata Motschulsky 1854, L. lateralis Motschulsky 1860, L. leii Fu et Ballantyne 2006, Lampyris noctiluca Linnaeus 1767, Pyrocoelia analis Fabricius 1801, P. pectoralis Oliver 1883, P. sp. and two Diaphanes species. In all cases the eversible organs are located on the pleural cuticle, dorsal to the spiracle, but there is considerable variation between species in their number, size and shape. In La. noctiluca they are confined to the abdomen, whereas in the other species they also occur on the meta- and mesothorax. In La. noctiluca and the Pyrocoelia species the organs are columnar in shape, contrasting with the forked organs of the Luciola and Diaphanes species. The eversible organs of the Luciola species, which are all aquatic, are remarkably larger (relative to body length) than those of the other, terrestrial species. On organ eversion the Luciola species emit an odour resembling pine oil, the Diaphanes species smell weakly of mint and L. noctiluca and the Pyrocoelia species produce no discernible scent, though ants are nonetheless repelled by contact with everted L. noctiluca organs. The organs of all the species studied support protuberances on their external surface, though these too vary in shape, size and ornamentation between species. In all species except L. noctiluca each protuberance is connected to a well-developed globular body via a long, thick stalk. Circular foveae are located in the centres of these globular bodies. The globular bodies consist of secretory cells characterized by the presence of numerous mitochondria and an extensive system of cisternae and tubular endoplasmic reticulum. Behavioural tests revealed that small larvae run away instead of becoming immobile and glowing, whereas large larvae start to glow when disturbed. The study shows that the eversible larval organs form an important part of a defensive arsenal in the Lampyridae.  相似文献   
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