664 research outputs found

    Evidence for the Effects of Wind on the Biogeography of Soil Mites in Urban Tree Wells

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    The theoretical predictions of island biogeography have been applied successfully by a number of researchers studying the population and community structures of invertebrates living in large urban parks and remnant natural areas. Few, however, have examined the biogeography of smaller patches and the role that specific dispersal techniques play in shaping species distributions. In this study, I examine the impact of several biogeographical and environmental factors, including wind channelization effects, on the abundance of soil mites in small, urban tree wells in Westminster, Maryland. By testing five models that include the variables of well area, isolation, and dominate wind direction, I account for all possible directions in which channelization effects may be directing wind flow most frequently, therefore accounting for the impact of wind dispersal on mite distribution. As one would expect if mite abundances were impacted by the dominate direction of wind flow on a given street, only one of these models significantly explained the pattern of mite abundances found from sampling the tree wells. While the low power of the models requires that these results be viewed as inconclusive, the unusually high amount of variance explained by the significant model (R2 = 0.76), along with its agreement with better established biogeographical relationships, does suggest that future research into the role of wind as a factor in the biogeography of passively dispersing urban invertebrates may be worthwhile

    Effect of information about organic production on beef liking and consumer willingness to pay

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    The present study was aimed to assess the effect of information about organic production on beef liking and consumer willingness to pay. Mean scores of perceived liking were higher for organic beef (OB) as compared to conventional beef (CB). Expected liking scores were higher for OB than for CB. For OB the expected liking was significantly higher than the perceived liking expressed in blind conditions (negative disconfirmation), whereas for CB no difference was observed. Consumers completely assimilated their liking for OB in the direction of expectations. Consumers showed a willingness to pay for OB higher than the suggested price (P < 0.001), the latter corresponding to the local commercial value for organic beef. We conclude that the information about organic farming can be a major determinant of beef liking, thus providing a potential tool for meat differentiation to traditional farms

    Resource heterogeneity and foraging behaviour of cattle across spatial scales

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    BackgroundUnderstanding the mechanisms that influence grazing selectivity in patchy environments is vital to promote sustainable production and conservation of cultivated and natural grasslands. To better understand how patch size and spatial dynamics influence selectivity in cattle, we examined grazing selectivity under 9 different treatments by offering alfalfa and fescue in patches of 3 sizes spaced with 1, 4, and 8 m between patches along an alley. We hypothesized that (1) selectivity is driven by preference for the forage species that maximizes forage intake over feeding scales ranging from single bites to patches along grazing paths, (2) that increasing patch size enhances selectivity for the preferred species, and that (3) increasing distances between patches restricts selectivity because of the aggregation of scale-specific behaviours across foraging scales.ResultsCows preferred and selected alfalfa, the species that yielded greater short-term intake rates (P &lt; 0.0001) and greater daily intake potential. Selectivity was not affected by patch arrangement, but it was scale dependent. Selectivity tended to emerge at the scale of feeding stations and became strongly significant at the bite scale, because of differences in bite mass between plant species. Greater distance between patches resulted in longer patch residence time and faster speed of travel but lower overall intake rate, consistent with maximization of intake rate. Larger patches resulted in greater residence time and higher intake rate.ConclusionWe conclude that patch size and spacing affect components of intake rate and, to a lesser extent, the selectivity of livestock at lower hierarchies of the grazing process, particularly by enticing livestock to make more even use of the available species as patches are spaced further apart. Thus, modifications in the spatial pattern of plant patches along with reductions in the temporal and spatial allocation of grazing may offer opportunities to improve uniformity of grazing by livestock and help sustain biodiversity and stability of plant communities

    Making the Most of Citation Data: The Integration of Thomson Reuters Web of Science and UWA's Research Management System, Socrates

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    In late 2006 The University of Western Australia launched Socrates, an online application designed to draw data from key research information systems, in order for the University to prepare portfolios for the Research Quality Framework (RQF). Socrates also incorporates bibliographic and citation data from Thomson Reuters’ Web of Science (WoS) using the web services interface (API). This presentation focuses upon the utilisation of Thomson Reuters’ data within Socrates. The benefits of importing Thomson Reuters’ data, including reducing the workload associated with the annual HERDC publications collection, and using imported research tags to trace the level of publication within specific disciplines, are explored. The presentation also outlines the technical problems faced by Socrates with regards to matching citation data imported from the WOS to data from the UWA Publications Database. Overall, it is argued that by drawing data from the WOS, Socrates is able to provide a detailed analysis of UWA’s indexed publications at a university, organisational unit and individual level, thereby shedding significant light on the University’s research output performance

    Using Ownership as an Incentive

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    Agency theory is used to develop hypotheses regarding the effects of ownership proliferation on firm performance. The authors examine the effects of chief executive officer (CEO) ownership, executive team ownership, and all employee ownership in addition to the moderating effect of risk on firm survival and stock price. Firms with low CEO ownership outperform those with high levels of CEO ownership across all levels of risk, but the effect is most pronounced for low-risk firms. Executive team ownership is negatively related to firm performance, whereas ownership for all employees is positively associated with firm performance, particularly for higher risk firms.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67316/2/10.1177_1059601199244003.pd

    Many Body Theory of Charge Transfer in Hyperthermal Atomic Scattering

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    We use the Newns-Anderson Hamiltonian to describe many-body electronic processes that occur when hyperthermal alkali atoms scatter off metallic surfaces. Following Brako and Newns, we expand the electronic many-body wavefunction in the number of particle-hole pairs (we keep terms up to and including a single particle-hole pair). We extend their earlier work by including level crossings, excited neutrals and negative ions. The full set of equations of motion are integrated numerically, without further approximations, to obtain the many-body amplitudes as a function of time. The velocity and work-function dependence of final state quantities such as the distribution of ion charges and excited atomic occupancies are compared with experiment. In particular, experiments that scatter alkali ions off clean Cu(001) surfaces in the energy range 5 to 1600 eV constrain the theory quantitatively. The neutralization probability of Na+^+ ions shows a minimum at intermediate velocity in agreement with the theory. This behavior contrasts with that of K+^+, which shows ... (7 figures, not included. Figure requests: [email protected])Comment: 43 pages, plain TeX, BUP-JBM-

    Practical Guidance for Integrating Data Management into Long-Term Ecological Monitoring Projects

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    Long-term monitoring and research projects are essential to understand ecological change and the effectiveness of management activities. An inherent characteristic of long-term projects is the need for consistent data collection over time, requiring rigorous attention to data management and quality assurance. Recent papers have provided broad recommendations for data management; however, practitioners need more detailed guidance and examples. We present general yet detailed guidance for the development of comprehensive, concise, and effective data management for monitoring projects. The guidance is presented as a graded approach, matching the scale of data management to the needs of the organization and the complexity of the project. We address the following topics: roles and responsibilities; consistent and precise data collection; calibration of field crews and instrumentation; management of tabular, photographic, video, and sound data; data completeness and quality; development of metadata; archiving data; and evaluation of existing data from other sources. This guidance will help practitioners execute effective data management, thereby, improving the quality and usability of data for meeting project objectives as well as broader meta-analysis and macrosystem ecology research
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