64 research outputs found

    Genetic studies of Northern Goshawks (Accipiter gentilis): genetic tagging and individual identification from feathers, and determining phylogeography, gene flow and population history for Goshawks in North America

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    Department Head: William K. Lauenroth.2008 Spring.Includes bibliographical references (pages 125-133).The Northern Goshawk (Accipiter gentilis) is a large, highly mobile, mostly nonmigratory and widespread forest raptor. It ranges across the Boreal forests from Alaska to Newfoundland, and south into forests of the Great Lakes, and montane regions of the Appalachian, Cascade, Sierra Nevada, Rocky Mountain, and Sierra Madre Occidental. There has been much interest in the population and taxonomic status of Northern Goshawks, especially for populations occurring west of the 100th meridian. The objectives of my dissertation were to (1) determine whether alternative methods to capture-recapture methods were feasible; and (2) evaluate the genetic relationships among goshawk populations across their continental U.S. range. The genetic "marking" studies (Chapters 1 and 2) provided feasible and cost-effective alternative methods for capture-recapture, and are logistically easier to implement. If used, these methods have the potential to standardize the collection of demographic data across the species' range. Assessment of the genetic status among goshawks (Chapter 3) indicated populations are subdivided at a regional scale, with some gene flow within and among regions

    Numerical Analysis on the Optimisation of Thermal Comfort Levels in an Office Located inside a Historical Building

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    The present study examines the possibility of thermal comfort optimisation inside an office room where, due to historical heritage, it is possible to modify neither the energetic characteristic of the envelope nor the position of the inlet air vents. The distribution of global and local thermal comfort indices is evaluated in both heating and cooling conditions by establishing a computational fluid dynamics (CFD) model validated against experimental data. The obtained results demonstrate a striking asymmetry of the air velocity and temperature distribution due to the low energy efficiency of the building. In heating mode, the predicted mean vote (PMV) values were improved if the discharged air from the fan coil was at its maximal velocity. However, at the same time, the vertical air temperature gradient increased by around 0.5 C in each working station. In the cooling condition, in the absence of the solar radiation, the minimal air-flow rate satisfied the acceptable range of the draught rate (DR), whereas in the presence of a solar load, it could not meet the required cooling load in all positions, leading to higher floor temperature. The findings of this study allow for identifying and rearranging the optimal position of working stations in terms of thermal comfort

    Lithium-ion battery thermal management systems : a survey and new CFD results

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    The environment has gained significant importance in recent years, and companies involved in several technology fields are moving in the direction of eco-friendly solutions. One of the most discussed topics in the automotive field is lithium-ion battery packs for electric vehicles and their battery thermal management systems (BTMSs). This work aims to show the most used lithium-ion battery pack cooling methods and technologies with best working temperature ranges together with the best performances. Different cooling methods are presented and discussed, with a focus on the comparison between air-cooling systems and liquid-cooling systems. In this context, a BTMS for cylindrical cells is presented, where the cells are arranged in staggered lines embedded in a solid structure and cooled through forced convection within channels. The thermal behavior of this BTMS is simulated by employing a computational fluid dynamics (CFD) approach. The effect of the geometry of the BTMS on the cell temperature distribution is obtained. It is shown that the use of materials with additives for the solid structure enhances the performance of the system, giving lower temperatures to the cells. The system is tested with air-cooling and water-cooling, showing that the best performances are obtained with water-cooling in terms of cell packing density and lowest cell temperatures

    Influence of different heating systems on thermal comfort perception: a dynamic and CFD analysis

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    In this paper, we investigate the influence of different heating systems on the thermal comfort indexes, Predicted Mean Vote (PMV) and Predicted Percentage of Dissatisfied (PPD), for a residential apartment located in Bologna (Italy). The apartment has an area of 40 m2 and is located on the ground floor of 4 floors building. The envelop consists in horizontal perforated bricks with internal thermal insulation material and two windows. The analyses are performed employing Trnsys, a commercial dynamic simulation software and Simcenter STAR-CCM+, a multiphysics computational fluid dynamics (CFD) software. The CFD analysis regards a steady condition of a typical winter day in Bologna. Thermal comfort indexes and thermal energy demand are studied comparing two different heating generation systems existing in the considered apartment: a condensing gas boiler coupled with radiators as terminal emitters and an air-to-air heat pump. By crossing the results obtained by the dynamical approach and by the CFD simulations, a two-objective methodology where energy consumption is minimised while thermal comfort is obtained, is presented

    Framing the Narrative: Female Fighters, External Audience Attitudes, and Transnational Support for Armed Rebellions

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    Female combatants play a central role in rebel efforts to cultivate and disseminate positive narratives regarding the movement and its political goals. Yet, the effectiveness of such strategies in shaping audience attitudes or generating tangible benefits for the group remains unclear. We propose and test a theory regarding the channels through which female fighters advance rebel goals. We argue that female fighters positively influence audience attitudes toward rebel groups by strengthening observers’ beliefs about their legitimacy and their decision to use armed tactics. We further contend that these effects directly help them secure support from transnational non-state actors and indirectly promote state support. We assess our arguments by combining a novel survey experiment in two countries with analyses of new cross-national data on female combatants and information about transnational support for rebels. The empirical results support our arguments and demonstrate the impact of gender framing on rebel efforts to secure support

    Ethics, empathy and fear in research on violent conflict

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    The discussion of ethics in the social sciences focuses on ‘doing no harm’ and ‘giving back’ to research participants, but does not explore the challenges of empathy and fear in research with participants in political violence and war. Drawing on 180 in-depth interviews on the Georgian-Abkhaz war of 1992-1993 collected over eight months between 2010 and 2013 primarily in Abkhazia, but also Georgia and Russia, I argue that researchers can come to empathize with some but fear other participants in past and present violence. These emotional responses can influence researchers’ ability to probe and interpret interviews and respondents’ ability to surpass strong positions to explore dilemmas of participation in violence. By empathizing with not only ‘victims’ and ‘non-fighters’ as I had expected based on my pre-existing moral-conceptual categories, but also participants in the war, I found that individuals adopted multiple overlapping roles and shifted between these roles in the changing conditions of violence. In contrast, failing to empathize with and fearing those who continued to participate in violence at the time of my interviews limited my ability to fully appreciate the complexity of their participation, but shed light on the context of violence in contemporary Abkhazia. This analysis shows that reflection on the role of empathy and fear in shaping our interactions with research participants can help advance our understanding of participation in violence and this difficult research context

    The ineffectiveness of entrepreneurship policy:Is policy formulation to blame?

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    Entrepreneurship policy has been criticised for its lack of effectiveness. Some scholars, such as Scott Shane in this journal, have argued that it is ‘bad’ public policy. But this simply begs the question why the legislative process should generate bad policy? To answer this question this study examines the UK’s enterprise policy process in the 2009–2010 period. It suggests that a key factor for the ineffectiveness of policy is how it is formulated. This stage in the policy process is seldom visible to those outside of government departments and has been largely ignored by prior research. The application of institutional theory provides a detailed theoretical understanding of the actors and the process by which enterprise policy is formulated. We find that by opening up the ‘black box’ of enterprise policy formulation, the process is dominated by powerful actors who govern the process with their interests

    Review of "Women in War: The Micro-Processes of Mobilization in El Salvador," by Jocelyn Viterna

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    International audienceBaux ruraux. Renouvellement, Conditions, Date d'appréciatio
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