986 resultados para Hazardous geographic environments


Relevância:

20.00% 20.00%

Publicador:

Resumo:

The purpose of this pilot study was to survey dentists in the St. Louis area to assess their subjective opinion of commonly used dental handpieces as well as history of noise exposure and use of hearing protection. Selected handpieces were then chosen to measure their output levels and determine if emissions are hazardous to the auditory system.

Relevância:

20.00% 20.00%

Publicador:

Relevância:

20.00% 20.00%

Publicador:

Relevância:

20.00% 20.00%

Publicador:

Resumo:

North American birds that feed on aerial insects are experiencing widespread population declines. An analysis of the North American Breeding Bird Survey trend estimates for 1966 to 2006 suggests that declines in this guild are significantly stronger than in passerines in general. The pattern of decline also shows a striking geographical gradient, with aerial insectivore declines becoming more prevalent towards the northeast of North America. Declines are also more acute in species that migrate long distances compared to those that migrate short distances. The declines become manifest, almost without exception, in the mid 1980s. The taxonomic breadth of these downward trends suggests that declines in aerial insectivore populations are linked to changes in populations of flying insects, and these changes might be indicative of underlying ecosystem changes.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The Short-eared Owl (Asio flammeus) is an open-country species breeding in the northern United States and Canada, and has likely experienced a long-term, range-wide, and substantial decline. However, the cause and magnitude of the decline is not well understood. We set forth to address the first two of six previously proposed conservation priorities to be addressed for this species: (1) better define habitat use and (2) improve population monitoring. We recruited 131 volunteers to survey over 6.2 million ha within the state of Idaho for Short-eared Owls during the 2015 breeding season. We surveyed 75 transects, 71 of which were surveyed twice, and detected Short-eared Owls on 27 transects. We performed multiscale occupancy modeling to identify habitat associations, and performed multiscale abundance modeling to generate a state-wide population estimate. Our results suggest that within the state of Idaho, Short-eared Owls are more often found in areas with marshland or riparian habitat or areas with greater amounts of sagebrush habitat at the 1750 ha transect scale. At the 50 ha point scale, Short-eared Owls tend to associate positively with fallow and bare dirt agricultural land and negatively with grassland. Cropland was not chosen at the broader transect scale suggesting that Short-eared Owls may prefer more heterogeneous landscapes. On the surface our results may seem contradictory to the presumed land use by a “grassland” species; however, the grasslands of the Intermountain West, consisting largely of invasive cheatgrass (Bromus tectorum), lack the complex structure shown to be preferred by these owls. We suggest the local adaptation to agriculture represents the next best habitat to their historical native habitat preferences. Regardless, we have confirmed regional differences that should be considered in conservation planning for this species. Last, our results demonstrate the feasibility, efficiency, and effectiveness of utilizing public participation in scientific research to achieve a robust sampling methodology across the broad geography of the Intermountain West.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

For several years, online educational tools such as Blackboard have been used by Universities to foster collaborative learning in an online setting. Such tools tend to be implemented in a top-down fashion, with the institution providing the tool to the students and instructing them to use it. Recently, however, a more informal, bottom up approach is increasingly being employed by the students themselves in the form of social networks such as Facebook. With over 9,000 registered Facebook users at the beginning of this study, rising to over 12,000 at the University of Reading alone, Facebook is becoming the de facto social network of choice for higher education students in the UK, and there was increasing anecdotal evidence that students were actively learning via Facebook rather than through BlackBoard. To test the validity of these anecdotes, a questionnaire was sent to students, asking them about their learning experiences via BlackBoard and Facebook. The results show that students are making use of the tools available to them even when there is no formal academic content, and that increased use of a social networking tool is correlated with a reported increase in learning as a result of that use.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Since the advent of the internet in every day life in the 1990s, the barriers to producing, distributing and consuming multimedia data such as videos, music, ebooks, etc. have steadily been lowered for most computer users so that almost everyone with internet access can join the online communities who both produce, consume and of course also share media artefacts. Along with this trend, the violation of personal data privacy and copyright has increased with illegal file sharing being rampant across many online communities particularly for certain music genres and amongst the younger age groups. This has had a devastating effect on the traditional media distribution market; in most cases leaving the distribution companies and the content owner with huge financial losses. To prove that a copyright violation has occurred one can deploy fingerprinting mechanisms to uniquely identify the property. However this is currently based on only uni-modal approaches. In this paper we describe some of the design challenges and architectural approaches to multi-modal fingerprinting currently being examined for evaluation studies within a PhD research programme on optimisation of multi-modal fingerprinting architectures. Accordingly we outline the available modalities that are being integrated through this research programme which aims to establish the optimal architecture for multi-modal media security protection over the internet as the online distribution environment for both legal and illegal distribution of media products.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

A wide range of issues relating to the presence and fate of pesticides and other micro-organic contaminants (MOCs) in surface freshwater sedimentary environments is reviewed. These issues include the sources, transport and occurrence of MOCs in freshwater environments; their ecological effects; their interaction with sedimentary material; and a range of processes related to their fate, including degradation, diffusion in bed sediments, bioturbation and slow contaminant release. An emphasis is placed on those processes-chemical, physical or biological-in which sediments play a role in determining the fate of micro-organics in freshwater environments. The issues of occurrence, source and transport, and the ecological effects of micro-organics are introduced more briefly, the focus where these aspects are concerned being largely on pesticides. In the concluding section, key points and issues relating to the study of micro-organics in freshwater environments are summarised and areas where initial or further research would be welcome are highlighted. It is hoped that this paper will both form a useful reference for workers in the field of micro-organic contaminants, and also stimulate new work in the freshwater environment and beyond. (C) 2003 Elsevier Science Ltd. All rights reserved.

Relevância:

20.00% 20.00%

Publicador:

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Historic environments, the basis for heritage tourism, are difficult to access for people with disabilities. Many countries have introduced legislation to promote equal rights for people with disabilities. Historic environments, however, enjoy protection under national planning systems which limit the physical access improvements that can be made. The significance of historic environments for tourism in the UK is outlined. Barriers restricting tourists with disabilities accessing historic sites are reviewed from the heritage tourism service provider's viewpoint. Interests of the major stakeholders are considered in terms of the apparent conflict between conservation and access issues as heritage tourism service providers seek to comply with disability discrimination legislation. From a study of access improvements made by major heritage tourism service providers, good practice is identified. However, physical access improvements to enable tourists with disabilities to visit historic environments are a compromise because of the strength of conservation interests. Questions remain as to whether this compromise is acceptable to the tourist with disabilities and whether intellectual access is an acceptable substitute for physical presence.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This paper reopens debates of geographic theorizations and conceptualizations of social capital. I argue that human geographers have tended to underplay the analytic value of social capital, by equating the concept with dominant policy interpretations. It is contended that geographers could more explicitly contribute to pervasive critical social science accounts. With this in mind, an embodied perspective of social capital is constructed. This synthesizes Bourdieu's capitals and performative theorizations of identity, to progress the concept of social capital in four key ways. First, this theorization more fully reconnects embodied differences to broader socioeconomic processes. Second, an exploration of how embodied social differences can emerge directly from the political-economy and/or via broader operations of power is facilitated. Third, a path is charted through the endurance of embodied inequalities and the potential for social transformation. Finally, embodied social capital can advance social science conceptualizations of the spatiality of social capital, by illuminating the importance of broader sociospatial contexts and relations to the embodiment of social capital within individuals.