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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
221

Mechanisms and consequences of interspecific competition in long-distance migrant birds

January 2020 (has links)
archives@tulane.edu / Although interspecific competition and relevant coexistence mechanisms are core concepts in ecology and evolution, most such research has focused on two-species interactions. Lacking is important information on how and when interspecific competition operates in more complex species assemblages. This dissertation examined interspecific competition and coexistence mechanisms between a focal species, the American redstart (Setophaga ruticilla, Parulidae) and its potential competitors in multiple communities. Using a theoretical framework that builds on the well documented population ecology of redstarts, combined with interspecific dietary overlaps, I demonstrate ongoing interspecific competition. I found that species generally both overlap highly in diet and exhibit small, but consistent, differences consistent with their foraging behavioral differences. Although some competitive interactions were mediated by direct aggressive interactions, this research also highlighted diffuse competition as more important than previously recognized. My findings also differed from systems that have shown similar patterns insofar as high dietary overlaps persisted during times of resource scarcity, were driven by overlaps on low value prey taxa, and did not involve exclusive use of any resources by different competitors. All of these factors increase the potential negative demographic effects of interspecific competition, some of which have been documented in these bird species. A long history of competition studies in these warblers has shown large differences in foraging behavior among species, assumed to be what allows coexistence. However, it is not clear how and if differences in foraging behavior correspond to differences in resource use. I confirmed that locally coexisting study species differed almost completely in foraging behavior, particularly in microhabitat use. Likewise, using a variety of arthropod sampling methods, I found that microhabitats differed greatly in their available prey. Combining the large differences in foraging behavior with available prey significantly predicted the small dietary differences, although it did a poor job of explaining the already limited variation in diet. Overall, I found mixed support for behavioral niche partitioning, leading me to examine alternative mechanisms of coexistence. Contrary to past work focused on interspecific interactions, I found that population level forces dominate in determining local distributions, with birds of the same species being more evenly distributed due to intraspecific territoriality. This pattern led to higher local (point count scale) species richness, and greater community covariance than predicted. This intraspecific territoriality and repulsion is proposed as as a novel coexistence mechanism. / 1 / Cody M. Kent
222

Essays on competition between fixed and mobile networks in the broadband industry and on scientific publications issued by innovative companies

Dewulf, Lauriane 22 May 2017 (has links) (PDF)
Abstact 1 - Over the past few years, mobile broadband technologies and speeds have greatly increased in the European Union, reaching an ever larger share of broadband consumers. These changes have implications for broadband market competition. In the past, mobile services offered slow but mobile internet whereas fixed services offered faster but fixed internet. Fixed and mobile broad-band were therefore obviously complementary services. While mobile broadband speeds have significantly increased over the latest years, fixed broadband is remaining rather a fixed technol-ogy. Consequently, if mobile broadband becomes fast enough considering some consumers’ needs, we believe that the same consumers will choose to use only the mobile broadband tech-nology (who by itself offers high-speed and mobility) instead of both fixed and mobile broad-band technologies. As a result, we may observe an increasing trend towards fixed to mobile substitution. Our study investigates empirically this trend. More specifically, it analyzes the im-pact of mobile broadband technology evolution - through 4G adoption - on fixed to mobile sub-stitution in the 28 European countries from 2009 until 2015. The few studies examining this sub-ject show that fixed to mobile substitution exists although none of these studies analyze the evo-lution of this substitution. The results confirm a significant existence of a fixed to mobile substi-tution in the EU, and show that this substitution is more than doubled when a country adopts 4G. The growing competitive pressure from mobile operators also provides fixed operators with incentives to acquire – or merge with – mobile operators. This fact should be a concern for policy makers as it could have harmful consequences for competition and investment on the broad-band market. / Abstract 2 - Whereas open science – i.e. publishing articles in scientific journals – had been largely studied on the academic side, there is still a need to explore the subject on the industry side. This study spe-cifically analyzes the role of academic institutions in firms’ scientific publications and uses a novel approach to explore the subject. Publications issued from collaborations with academic institutions are indeed differentiated from other publications. The first type of publications is considered as an indicator of firms’ collaborative activities with academic institutions whereas the second type of publications is considered as the result of firms’ strategies and/or firms’ capa-bilities to publish. This study provides evidence that industry publications are a valuable signal to attract academic partners. In addition, this study provides evidence that potential academic partners are more willing to team up with firms’ researchers who have proven their ability to achieve high-quality research/publications without the help of academic partners. Finally, the study provides evidence that past successful collaborations with academic partners lead the firm to reiterate such collaborations in the short term (2 years max.). / Abstract 3 - The objective of this study is twofold. First, it provides further knowledge on the subject of prof-itability of industry science/publications as it is not clear yet whether industry sci-ence/publications are profitable to firms. Second, it considers the central role of academic part-ners in the profitability of firms’ scientific publications as previous empirical studies do not con-sider such role. To investigate the subject, we perform several regressions with firms profits as dependent variable. The results provide evidence that the publication of scientific articles is not a profitable activity in itself (as it was demonstrated in two previous studies). Collaborations with academic institutions are the real basis of profitable results; the production of scientific publica-tions is only one of the consequences of these collaborations. This study also shows that not all collaborations are profitable, only collaborations in high-tech sectors that lead to high-quality publications lead to larger profits. Indeed, in their quest for survival and profitability, companies competing in high-tech sectors often need the help of academic partners to exploit scientific knowledge. On average, a rise of about 7% in successful collaborations (leading to high-quality publications) raises the profit of high-tech firms by about 1%. - / Abstract 4 - This chapter analyzes the factors influencing the quality of the output of I-A collaborations ap-proximated by the quality of the I-A co-publications. More specifically it analyzes two subjects that are typically complicated to study empirically because of a lack of available data: (1) it compares US and EU I-A partnerships and (2) it discusses if and how internet is a useful tool in I-A collaborations. The results empirically confirm that EU universities are less efficient partners than US universities when collaborating with the private sector. This study also demonstrates a much larger gap between EU and US academic partners in high-tech sectors. Finally, the results provide evidence that broadband is a useful tool for international I-A collaborations although broadband is less important in the success of I-A international collaborations in high-tech sectors compared to lower-tech sectors. / Doctorat en Sciences économiques et de gestion / info:eu-repo/semantics/nonPublished
223

Harm in Harmony: A Socioecological Perspective on East Asian Collectivism

Liu, Shi January 2020 (has links)
Decades of research have described East Asian cultures as collectivistic, often characterized by ingroup relationships that are harmonious and cooperative. I propose an alternative account of East Asian Collectivism—the Harm-in-Harmony Theory. Specifically, I propose that East Asian culture can be better understood as a tension between high levels of cooperation and competition within groups. The co-existence of cooperation and competition drives competition covert. To cope with covert competition, people in East Asia develop a heightened threat-detection system—ingroup vigilance—a cognitive tendency to perceive ingroup members as hostile and threatening. The Harm-in-Harmony theory provides an alternative account for a number of cross-cultural differences (i.e., East Asians being more responsive and attentive to others) that have previously been explained through harmonious interdependence. This work contributes to a more balanced view of collectivism, revealing its interpersonal tensions in the forms of covert competition and ingroup vigilance.
224

The Competition Commission's non-referral of exclusivity clauses in the shopping centre lease context: a monumental misjudgement - A Section 5(1) analysis of anticompetitiveness

Blumenthal, Roxanne January 2015 (has links)
This paper focuses on the common practice in commercial agreements of including exclusivity clauses in shopping centre lease agreements between a supermarket anchor tenant and the landlord of a shopping centre. It is the contention of this paper that such clause s are anticompetitive when considered specifically in light of section 5(1) of the South African Competition Act. In reaching this conclusion, relevant sect ions of the Act will be interpreted and analysed in the pertinent context, as will relevant case law and comparable foreign jurisprudence. The findings of South Africa's Competition Commission in 2013 with regard to the competitive nature of exclusivity clauses in the context of section 5(1), and the basis for their findings will be scrutinised. A conclusion , warranted and supported by the inferences drawn from an analysis of the aforementioned sources (legislation, case law and foreign jurisprudence), will be reached accordingly in support of a stance of resistance against exclusivity clauses in shopping centre leases between landlord and supermarkets . An argument in favour of a blanket prohibition of exclusivity clauses in shopping centre leases due to their anticompetitive nature that outweighs their efficiencies and justifications according to section 5(1) of the Act, is the predominant direction of this paper.
225

Trade liberalisation in the East African Community: the need for competition law and policy in Uganda

Mugaino, Baker January 2012 (has links)
This study will show the relevance of competition policy and law is not only stopping anti-competitive practices but also its role in complimenting government reforms and policies in Uganda. The research will contribute to the development of the relevant competition law legislation for Uganda. The motivation of the study is derived from the competition challenges facing Uganda today, a country that has liberalised and privatised its economy but has no competition policy and law.
226

Social and political goals of mergers in competition law: comparative analysis of the efficiency and public interest provisions in Kenya and South Africa

Gitonga, Robert Kaniu January 2015 (has links)
Includes bibliographical references / A principal goal of competition law is to promote fair distribution of wealth. Fair distribution of wealth is entrusted to competitive markets since they reward efficiency, innovation, spread wealth and decentralise economic power. While competition reflects the business conduct of enterprises, it cannot disassociate from the legal and regulatory framework, barriers to entry and prevailing conditions in markets for labour, infrastructure services and other production inputs. Redistribution of wealth acknowledges competition law as a tool that can be utilised to protect those at the lower end of income distribution by reducing prices allowing a larger basket of goods and services to be purchased. Competition law is a tool that preserves market competition to provide an environment that encourages responsive business, efficiency and serves the interests of consumers. In developing countries, competition law and policy receive particular emphasis as being crucial and key in the economic and structural reform and addressing concerns of distribution and power. Competition law in Kenya cannot ignore the wider industrial policy or socio-economic considerations in Kenya. These social and political goals of competition law are important in developing countries with poverty, great income inequality. There is need to choose a means of addressing the equitable allocation of resources that will produce the least amount of inefficiency and competition law is the right tool to achieve this. Kenya is a factor-driven economy where the level of productivity is determined by labour, institutions, infrastructure and the macro-economic environment. Enacting the Competition Act in Kenya was a response to economic and political reform to improve the welfare, well-being and economy in Kenya. Merger analysis in Kenya would require weighing gains and losses in efficiency in order to establish whether the merger will benefit other recipients other than market participants such as consumers and producers. South Africa has well established interpretation and implementation addressing the trade-off between public interest provisions and efficiency. Interpretation of the merger laws in South Africa illustrate engaging an exercise of proportionality required to determine how to balance the competing arguments between efficiency, welfare standards and public interest.
227

Potential competition and multi-product activity

Mahabir, Dhanayshar January 1994 (has links)
No description available.
228

Intraspecific competition in yellow nutsedge (Cyperus esculentus L.)

Sterkenburg, Neilda Jane January 1989 (has links)
No description available.
229

The Ecological Niche of Darters (Pisces:Percidae) Across Multiple Scales in the Ohio River Basin

Crail, Todd D. January 2012 (has links)
No description available.
230

A study of competition with special reference to its role in public education /

Brundage, Ervin Elmer January 1956 (has links)
No description available.

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