From Strong to Weak Coupling Regime in a Single GaN Microwire up to Room Temperature

Large bandgap semiconductor microwires constitute a very advantageous alternative to planar microcavities in the context of room temperature strong coupling regime between exciton and light. In this work we demonstrate that in a GaN microwire, the strong coupling regime is achieved up to room temperature with a large Rabi splitting of 125 meV never achieved before in a Nitride-based photonic nanostructure. The demonstration relies on a method which doesn't require any knowledge \'a priori on the photonic eigenmodes energy in the microwire, i.e. the details of the microwire cross-section shape. Moreover, using a heavily doped segment within the same microwire, we confirm experimentally that free excitons provide the oscillator strength for this strong coupling regime. The measured Rabi splitting to linewidth ratio of 15 matches state of the art planar Nitride-based microcavities, in spite of a much simpler design and a less demanding fabrication process. These results show that GaN microwires constitute a simpler and promising system to achieve electrically pumped lasing in the strong coupling regime.Comment: 14 pages, 4 figure

Fabrication and Optical Properties of a Fully Hybrid Epitaxial ZnO-Based Microcavity in the Strong Coupling Regime

In order to achieve polariton lasing at room temperature, a new fabrication methodology for planar microcavities is proposed: a ZnO-based microcavity in which the active region is epitaxially grown on an AlGaN/AlN/Si substrate and in which two dielectric mirrors are used. This approach allows as to simultaneously obtain a high-quality active layer together with a high photonic confinement as demonstrated through macro-, and micro-photoluminescence ({\mu}-PL) and reflectivity experiments. A quality factor of 675 and a maximum PL emission at k=0 are evidenced thanks to {\mu}-PL, revealing an efficient polaritonic relaxation even at low excitation power.Comment: 12 pages, 3 figure

LO-phonon assisted polariton lasing in a ZnO based microcavity

Polariton relaxation mechanisms are analysed experimentally and theoretically in a ZnO-based polariton laser. A minimum lasing threshold is obtained when the energy difference between the exciton reservoir and the bottom of the lower polariton branch is resonant with the LO phonon energy. Tuning off this resonance increases the threshold, and exciton-exciton scattering processes become involved in the polariton relaxation. These observations are qualitatively reproduced by simulations based on the numerical solution of the semi-classical Boltzmann equations

Sobre a (im)prescritibilidade da pretensão de ressarcimento de danos causados ao erário por ato de improbidade administrativa

TCC(graduação) - Universidade Federal de Santa Catarina. Centro de Ciências Jurídicas. Direito.O presente trabalho objetiva dirimir a dúvida existente acerca da sujeição da pretensão de ressarcimento de danos causados ao erário por ato de improbidade administrativa ao instituto da prescrição. Tal incerteza surge a partir da redação da ressalva contida no artigo 37, § 5º, da Constituição da República Federativa do Brasil, que possibilita variadas interpretações, algumas defendendo a imprescritibilidade de tal pretensão, outras advogando a tese da sujeição de tal pretensão a lapso prescricional. Com o fito de se concluir pelo entendimento mais condizente à ordem jurídico-normativa brasileira, divide-se o estudo em três capítulos principais. No primeiro, são delineados o conceito e a finalidade da prescrição, apresentando-se a garantia da segurança jurídica como sendo seu fundamento constitucional. Em seguida, são explanadas as noções de supremacia do interesse público e segurança jurídica, entendidas por boa parte dos estudiosos como os dois princípios a partir dos quais deve ser analisada a questão. Por fim, no terceiro e último capítulo, depois de serem descritas as principais interpretações que podem derivar da leitura do dispositivo, chega-se ao entendimento pela conformação da pretensão estudada ao manto prescricional. Esta acepção parece melhor se amoldar aos contornos pretendidos pelo ordenamento jurídico-constitucional contemporâneo para a construção de um Direito Administrativo efetivamente democrático, com a sobrevalorização dos direitos fundamentais, individuais e coletivos, e a realização da ideia de supremacia da Constituição. No plano legal e normativo, a compreensão pela prescritibilidade afigura-se coerente à própria construção histórica do comando constitucional, com a delimitação de dois regimes prescricionais distintos para as pretensões originadas com a prática de ato de improbidade. Da mesma forma, a identificação do ressarcimento como consequência, e não sanção, do ato ímprobo, bem como a evolução do tratamento dado à matéria pelo Supremo Tribunal Federal parecem caminhar no mesmo sentido interpretativo

“Either Everyone Was Guilty or Everyone Was Innocent”: The Italian Power Elite, Neopatrimonialism, and the Importance of Social Relations

Rarely does the Byzantine world of football administration get exposed as clearly as during the 2006 calciopoli scandal. This scandal laid bare the interpersonal relationships of football administrators at the top three Italian men’s football clubs: Juventus, Inter, and AC Milan. This article draws on the media leaks that revealed the inner workings of those working within football to argue that the football clubs are pyramids of power for club presidents that allows them to operate within the Italian power elite. This is done through interpersonal clientelistic networks that operate within a neopatrimonial system. Theoretically, this article draws on four main concepts: C. Wright Mills’s concept of the Power Elite, Lomnitz’s model of “Pyramids of Power,” Eisenstadt’s notion of neopatrimonialism, and Mauss’s utilization of the gift. Power is exercised through quid pro quo relationships, with certain key individuals operating as brokers to the flow of favors throughout the network

Global Transcriptional Programs in Peripheral Nerve Endoneurium and DRG Are Resistant to the Onset of Type 1 Diabetic Neuropathy in Ins2Akita/+ Mice

While the morphological and electrophysiological changes underlying diabetic peripheral neuropathy (DPN) are relatively well described, the involved molecular mechanisms remain poorly understood. In this study, we investigated whether phenotypic changes associated with early DPN are correlated with transcriptional alterations in the neuronal (dorsal root ganglia [DRG]) or the glial (endoneurium) compartments of the peripheral nerve. We used Ins2Akita/+ mice to study transcriptional changes underlying the onset of DPN in type 1 diabetes mellitus (DM). Weight, blood glucose and motor nerve conduction velocity (MNCV) were measured in Ins2Akita/+ and control mice during the first three months of life in order to determine the onset of DPN. Based on this phenotypic characterization, we performed gene expression profiling using sciatic nerve endoneurium and DRG isolated from pre-symptomatic and early symptomatic Ins2Akita/+ mice and sex-matched littermate controls. Our phenotypic analysis of Ins2Akita/+ mice revealed that DPN, as measured by reduced MNCV, is detectable in affected animals already one week after the onset of hyperglycemia. Surprisingly, the onset of DPN was not associated with any major persistent changes in gene expression profiles in either sciatic nerve endoneurium or DRG. Our data thus demonstrated that the transcriptional programs in both endoneurial and neuronal compartments of the peripheral nerve are relatively resistant to the onset of hyperglycemia and hypoinsulinemia suggesting that either minor transcriptional alterations or changes on the proteomic level are responsible for the functional deficits associated with the onset of DPN in type 1 DM