2,831 research outputs found

    THz laser based on dipolaritons

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    We develop the microscopic theory of a terahertz (THz) laser based on the effects of resonant tunneling in a double quantum well heterostructure embedded in both optical and THz cavities. In the strong coupling regime the system hosts dipolaritons, hybrid quasiparticles formed by the direct exciton, indirect exciton and optical photon, which possess large dipole moments in the growth direction. Their radiative coupling to the mode of a THz cavity combined with strong non-linearities provided by exciton-exciton interactions allows for stable emission of THz radiation in the regime of the continuous optical excitation. The optimal parameters for maximizing the THz signal output power are analyzed.Comment: 8 pages, 7 figure

    Beyond Technological Diversification: The Impact of Employee Diversity on Innovation

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    This paper investigates the effect of employee diversity in terms of gender, age, ethnicity and education on the firm’s likelihood of introducing an innovation. The analysis draws on data from a recent innovation survey. This data is merged with a linked employer-employee dataset that allow us to identify the employee composition of each firm. We test the hypothesis that employee diversity is associated with better innovative performance. The econometric analysis reveals positive, negative and non-significant effects of the different employee characteristics on the likelihood of introducing an innovation.Diversity, Innovation, Education, Gender, Cultural Backgrund

    The Spectre of Bandung : China, the Global South, and the End of Colonial Trade Patterns

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    This thesis analysed the development of international trade patterns during the period from 1980 to 2013. More specifically, the research focused on the structure of North-South relations during this period and how China has influenced its dynamic. The legacy of colonialism left behind a particlar configuration of international trade, which was highly disadvantageous for the countries of the global South. This ‘core-periphery trade structure’ proved resilient in the decades following decolonisation, reinforcing the South’s subordinate position in the world economy. This research used the gravity model of international trade to trace the development of this trade structure over the last three and a half decades. The research found that patterns of international trade continued to reflect the structural legacy of colonialism throughout most of the twentieth century. However, this structure dissolved around the turn of the millennium as South-South trade started to grow and the North lost its centrality. The growing weight of China in the world economy was an important part of this development. However, the growth of South-South trade is not only a reorientation towards China. It also reflects a system-wide transformation towards a more balanced international trade structure

    Effects of changes in the Icelandic capital controls: An event study on the stock price of Össur hf.

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    The aim of the thesis is to examine whether changes in the capital controls affect the premium of the cross-listed stock of Össur hf., it is listed on the Icelandic and Copenhagen stock exchange. The price difference is examined with two currency rates, the official rate as given by the Central bank of Iceland and the offshore rate. The Icelandic market is bounded within capital controls, while the market in Denmark is not. From the introduction of the capital controls in 2008, they have been a subject of continuous change, and this study examines the effects of these changes on the premium between the Icelandic and Danish Össur stocks. The study uses a market model, adjusted for timevarying volatility, which contributes more concrete results. The results from the study indicate strongly, that the price differential is affected by the changes in the capital controls. Moreover, how the change is implemented is a key factor in the overall significance of the change

    Mitochondrial DNA Analysis by Denaturing High-Performance Liquid Chromatography for the Characterization and Separation of Mixtures in Forensic Samples

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    A mixture of different mtDNA molecules in a single sample is a significant obstacle to the successful use of standard methods of mtDNA analysis (i.e., dideoxy dye-terminator sequencing). Forensic analysts often encounter either naturally occurring mixtures (e.g., heteroplasmy) or situational mixtures typically arising from a combination of body fluids from separate individuals. The ability to accurately resolve and interpret these types of samples in a timely and cost efficient manner would substantially increase the power of mtDNA analysis and potentially provide valuable investigative information by allowing its use in cases where the current approach is limited or fails. Therefore, this research was aimed at developing a strategy for the use of Denaturing High-Performance Liquid Chromatography (DHPLC) as a developmentally-validated forensic application for resolving mixtures of mtDNA. To facilitate the adoption of this technology by the forensic community, a significant effort has been made to ensure that this technology meets the Scientific Working Group on DNA Analysis Methods (SWGDAM) developmental validation criteria and interfaces smoothly with previously validated methods of forensic mtDNA analysis. To do this, the method developed using DHPLC employs mtDNA amplicons, PCR conditions and DNA sequencing protocols validated for use in forensic laboratories. These factors are essential in implementing DHPLC analysis in a forensic casework environment and for the admissibility of DHPLC and Linkage Phase Analysis in court

    Webs of World Order : A Relational Theory of Rising Powers and the Evolution of International Order

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    This dissertation advances a relational theory of rising powers and their influence on international order. The emergence of new great powers and the relative decline of incumbent ones is an inherent feature of world politics. In the modern world, these power transitions have taken place against the background of a core- periphery shaped structure of global relations. Great powers vied for dominance while at the same time expanding their reach across the globe, incorporating smaller states into the empires and spheres of influence in a ‘hub-and-spoke’ manner. Today, however, this core-periphery structure is unravelling. A unique feature of the current power transition is that it takes place against the backdrop of a dense and decentred structure of global relations. This dissertation argues that this transformation in the global structure of relations has profound implications for the nature of great power competition, as well as the nature and evolution of international order. To grasp those implications, this dissertation advances a relational theory of international order.Article 1 provides the basis. It argues that the global structure of relations should be posited as the ‘subject’ of international order. The reach of international order is thus neither ubiquitous nor self-evident, but follows the dynamic structure of global relations between states over time. Today, the subject of international order is growing beyond the reach of the old liberal order.Article 2 assesses the state of the Liberal International Order in East Asia. Its core argument is that we need to theorise international order independently of the power and preferences of hegemonic states such as the US. International order is thus construed as a supranational political construct. Despite relative US decline, it finds strong support for the liberal order in East Asia.Article 3 discusses the influence of relational structures on the nature of great power competition. It argues that the dense and decentred structure that is emerging reduces the incentives for aggressive great power competition compared to the previous core-periphery structure. It also argues that this decentred structure gives rising powers more ‘space’ for international building without impinging on the home turf of existing powers

    Managing warfarin treatment in a small Icelandic rural practice in Húsavík

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    Hægt er að lesa greinina í heild sinni með því að smella á hlekkinn View/OpenOBJECTIVE: To investigate the efficiency of warfarin management in Húsavík Health Care Center. MATERIAL AND METHODS: All patients receiving warfarin treatment managed in Húsavík in the years 2001 and 2003 were included in the study. Main outcome measures were the percentage time within INR target range (Rosendaal) and whether the management was deemed satisfactory or unsatisfactory (defined as <3 measurements per year). RESULTS: In 2001 there were 34 patients receiving warfarin treatment in Húsavík but 57 in 2003. Median age was 71.5 and 76 years, 65% and 67% were males, indication for treatment was atrial fibrillation in 53% and 73% and INR target range was 2.0-3.0 in 74% and 86% respectively. The management was deemed unsatisfactory in 38.2% in 2001 but 10.5% in 2003 (27.7% absolute reduction, p=0.0017). Percentage time spent within target range was 61.2% and 63.1% respectively. CONCLUSION: These findings suggest that the quality of anticoagulant control in Húsavík is adequate and fully comparable with that shown in previous studies from our neighbouring countries.Tilgangur: Að athuga hversu vel gengi að stýra blóðþynningarmeðferð með warfaríni frá Heil­brigðisstofnun Þingeyinga (HÞ) samanborið við aðrar rannsóknir og hvort breytingar sem urðu á framkvæmd eftirlitsins árið 2002 hefðu orðið til bóta. Niðurstöður: Árið 2001 voru 34 sjúklingar á blóðþynningarmeðferð sem stýrt var frá HÞ en 57 árið 2003. Miðgildi aldurs var 71,5 og 76 ár, karlar voru 22 (65%) og 38 (67%). Ábending meðferðar var gáttatif í 53% og 73% tilvika og markgildi INR var 2-3 í 74% og 86% tilvika. Árið 2001 voru 13 af 34 sjúklingum (38,2%) undir ófullnægjandi eftirliti en árið 2003 voru þeir 6 af 57 (10,5%). Munurinn var því 27,7% (p=0,0017). Sjúklingarnir voru 61,2% og 63,1% tímans innan markgildis og meðal mæl­ingafjöldi var sex árið 2001 en 12 árið 2003. Eitt tilvik blóðtappa í heila var árið 2001 og eitt tilvik blæðingar sem krafðist innlagnar árið 2003. Ályktanir: Stjórnun blóðþynningarmeðferðar á HÞ er sambærileg því sem gerist erlendis og betur gengur að halda sjúklingum á meðferð í fullnægjandi eftirliti eftir að breytt var um fyrirkomulag