1,341 research outputs found

    The Autumn Migration of Thick-billed Murres near Southern Baffin Island and Northern Labrador

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    Aerial surveys were used to assess the timing and route of the swimming migration of Thick-billed Murres (Uria lomvia) near southern Baffin Island and northern Labrador in the autumn of 1977, 1978 and 1979. Several hundred thousand adults and chicks from six southern Baffin area colonies departed east through Hudson Strait, in the direction of surface currents, in the latter half of August. Most murres from three eastern Hudson Strait colonies were in offshore waters in early September, arrived in the northern Labrador Sea within a few days, and were followed later in September by murres from three western Hudson Strait colonies. From the Labrador Sea, murres go to marine wintering sites around Newfoundland. Murres from a large colony on southeast Baffin Island apparently did not migrate to the Labrador Sea through western Davis Strait; instead, they either migrated through central Davis Strait en route to Newfoundland, or east to west Greenland, which was also the probable destination of many adult murres which flew by a drillship in southwest Davis Strait.Key words: Thick-billed Murre (Uria lomvia), migration, Baffin Island, Davis Strait, Labrador Sea, eastern Canada, colonial seabirdMots clés: Marmette de Brünnich (Uria lomvia), migration, île de Baffin, détroit Davis, mer du Labrador, est du Canada, oiseau marin vivant en coloni

    An epidemiological and economic framework for evaluating the tangible and intangible impacts of emergency animal disease outbreaks

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    The economics of emergency animal disease outbreak response is impacted by a range of factors, such as the likelihood of an event occurring, species affected, frequency and distribution of disease incursions, transmission cycles, host interactions and climatic anomalies. Whilst empirically focussed economic evaluation tools for analysis and evaluation of control and prevention options are in frequent use, insights can be gained from an expanded framework that incorporates value-drivers used to justify decisions. The framework is build around an extrapolated cost-benefit analysis (CBA) that incorporates tangible and intangible elements. Primary steps involve risk analysis to ascertain the magnitude, priority and impact of the potential emergency situation. The framework also allows the operator to value-add to the CBA by incorporating non-commercial intangibles (such as environment, human health and animal welfare) using a series of value multipliers. These are essentially an averaged preference for a nominated approach or intervention along a scale of potential value placements using an axiological methodology. The outcome of the framework represents a holistically adjusted parametric. Potential uses of these outcomes could include (but are not limited to): (1) development of new policy for emergency animal diseases in peace time (Preparedness phase); (2) during consultative processes where multiple perspectives and values must be identified and considered: (1) for economic (tangible and intangible) justification of adjustments to response policy during an exotic animal disease (control phase); (2) for comparing and contrasting the economic (tangible and intangible) consequences of a particular control or prevention policy A case study using Hendra Virus will be given

    An industry-level analysis of potential intangible and economic impacts affecting Australian pork producers during an emergency animal disease control program

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    Emerging and transboundary diseases have been responsible for dramatic impacts on human health, the economy, trade, animal health and biodiversity in Australia and around the world. The Australian pig industry’s health status provides it with a competitive advantage. Freedom from major transboundary diseases – such as foot-and-mouth disease and classical swine fever – secures access to international markets and enables producers to invest in their businesses free from the complication of major disease incursions, ensures the industry’s future sustainability and allows it to meet community standards for food production. Planning for a disease response is driven by many factors. Among these factors, the cost of the response is often the single most important driving factor. However, cost involves more than the actual financial cost of the response. It involves a number of intangible elements and the views of a diverse range of stakeholders. For example, human health, environmental and sociological consequences need to be considered. Currently, a unifying framework for such decision-making is unavailable. Application of a newly developed framework to several diseases that concern the Australian pig industry will facilitate dialogue on what is the best response to minimize the impact of incursions of such diseases. This novel framework for economic analysis of animal health emergencies incorporates risk assessment, tangible and intangible elements and a value-added cost-benefit analysis. These case studies assess the comparability, applicability and accountability of different response actions through producer perspectives. An example of the application of this framework for a disease which threatens the Australian pig industry will be presented

    New light on Chinese enterprises in Africa: Findings from a recent survey of Chinese firms in Kampala, the capital of Uganda

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    Abstract In this paper five issues will be analyzed. In the first place that no separation is made between providing Chinese aid, developing trade relations with China and starting investment activities in Africa. Secondly, is it true that the Chinese government helps Chinese entrepreneurs to get started in Africa. In the third place it is often suggested that Chinese entrepreneurs start after a Chinese aid project or construction job. Another issue is the presence of Chinese traders: what is the role of Chinese whole sale or retail traders in Africa and why are these entrepreneurs so successful? Finally we will look at employment and environmental issues in which Chinese entrepreneurs are said to be involved. Based on interviews of 42 Chinese enterprises in Uganda evidence is presented concerning what types of enterprises moved into Uganda and for which reason? We will analyze to what extent Chinese enterprises employ Chinese workers and Ugandan managers. What motivates these Chinese entrepreneurs to invest in Uganda and how do they deal with the challenges such as labour and environmental legislation? Which problems do they face? The relations between Uganda and China are influenced by the influx of Chinese enterprises in Uganda and the issues this raises. African countries are sensitive to the issue of Chinese companies competing with African firms. Many African countries question whether Chinese (small) traders are necessary to sell Chinese products in Africa. To what extent are 'wholesale' shops in Uganda in fact involved in retail business and how does Uganda react to this? The analysis challenges some of the generalizations concerning China's presence in Africa. We conclude that Uganda is becoming increasingly proactive in its relationship and tries to increase the contribution of Chinese enterprises to the Ugandan economy, while defining the terms on which Chinese citizens can come to work in Uganda

    New Light on Chinese enterprises in Africa

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    In this paper five issues will be analyzed. In the first place that no separation is made between providing Chinese aid, developing trade relations with China and starting investment activities in Africa. Secondly, is it true that the Chinese government helps Chinese entrepreneurs to get started in Africa. I

    Emission spectra and intrinsic optical bistability in a two-level medium

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    Scattering of resonant radiation in a dense two-level medium is studied theoretically with account for local field effects and renormalization of the resonance frequency. Intrinsic optical bistability is viewed as switching between different spectral patterns of fluorescent light controlled by the incident field strength. Response spectra are calculated analytically for the entire hysteresis loop of atomic excitation. The equations to describe the non-linear interaction of an atomic ensemble with light are derived from the Bogolubov-Born-Green-Kirkwood-Yvon hierarchy for reduced single particle density matrices of atoms and quantized field modes and their correlation operators. The spectral power of scattered light with separated coherent and incoherent constituents is obtained straightforwardly within the hierarchy. The formula obtained for emission spectra can be used to distinguish between possible mechanisms suggested to produce intrinsic bistability.Comment: 18 pages, 5 figure

    Feline parvovirus seroprevalence is high in domestic cats from disease outbreak and non-outbreak regions in Australia

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    Multiple, epizootic outbreaks of feline panleukopenia (FPL) caused by feline parvovirus (FPV) occurred in eastern Australia between 2014 and 2018. Most affected cats were unvaccinated. We hypothesised that low population immunity was a major driver of re-emergent FPL. The aim of this study was to (i) determine the prevalence and predictors of seroprotective titres to FPV among shelter-housed and owned cats, and (ii) compare the prevalence of seroprotection between a region affected and unaffected by FPL outbreaks. FPV antibodies were detected by haemagglutination inhibition assay on sera from 523 cats and titres ≥1:40 were considered protective. Socioeconomic indices based on postcode and census data were included in the risk factor analysis. The prevalence of protective FPV antibody titres was high overall (94.3%), even though only 42% of cats were known to be vaccinated, and was not significantly different between outbreak and non-outbreak regions. On multivariable logistic regression analysis vaccinated cats were 29.94 times more likely to have protective FPV titres than cats not known to be vaccinated. Cats from postcodes of relatively less socioeconomic disadvantage were 5.93 times more likely to have protective FPV titres. The predictors identified for FPV seroprotective titres indicate targeted vaccination strategies in regions of socioeconomic disadvantage would be beneficial to increase population immunity. The critical level of vaccine coverage required to halt FPV transmission and prevent FPL outbreaks should be determined

    The Dynamical Cluster Approximation: Non-Local Dynamics of Correlated Electron Systems

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    We recently introduced the dynamical cluster approximation(DCA), a new technique that includes short-ranged dynamical correlations in addition to the local dynamics of the dynamical mean field approximation while preserving causality. The technique is based on an iterative self-consistency scheme on a finite size periodic cluster. The dynamical mean field approximation (exact result) is obtained by taking the cluster to a single site (the thermodynamic limit). Here, we provide details of our method, explicitly show that it is causal, systematic, Φ\Phi-derivable, and that it becomes conserving as the cluster size increases. We demonstrate the DCA by applying it to a Quantum Monte Carlo and Exact Enumeration study of the two-dimensional Falicov-Kimball model. The resulting spectral functions preserve causality, and the spectra and the CDW transition temperature converge quickly and systematically to the thermodynamic limit as the cluster size increases.Comment: 19 pages, 13 postscript figures, revte

    Simulations of the Static Friction Due to Adsorbed Molecules

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    The static friction between crystalline surfaces separated by a molecularly thin layer of adsorbed molecules is calculated using molecular dynamics simulations. These molecules naturally lead to a finite static friction that is consistent with macroscopic friction laws. Crystalline alignment, sliding direction, and the number of adsorbed molecules are not controlled in most experiments and are shown to have little effect on the friction. Temperature, molecular geometry and interaction potentials can have larger effects on friction. The observed trends in friction can be understood in terms of a simple hard sphere model.Comment: 13 pages, 13 figure
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