Observations of Very High Energy Gamma-Rays during Moonlight and Twilight with the MAGIC Telescope

We study the capability of the MAGIC telescope to observe under moderate moonlight. TeV gamma-ray signals from the Crab nebula were detected with the MAGIC telescope during periods when the Moon was above the horizon and during twilight. This was accomplished by increasing the trigger discriminator thresholds. No change is necessary in the high voltage settings since the camera PMTs were especially designed to avoid high currents. We characterize the telescope performance by studying the effect of the moonlight on the gamma-ray detection efficiency and sensitivity, as well as on the energy threshold.Comment: Contribution to the 30th ICRC, Merida Mexico, July 2007 on behalf of the MAGIC Collaboratio

Les avantages du règlement consensuel en matière de réparation du préjudice corporel : le cas particulier de la transaction à paiements différés

Les difficultés soulevées par l'octroi d'une indemnité forfaitaire pour préjudice corporel ont poussé les parties impliquées dans ce type de litige vers des modes de règlement consensuel. La détermination de l'expectative de vie de la victime, l'incidence de l'inflation et de l'impôt, la difficulté sous le régime de la somme forfaitaire d'assurer une indemnisation complète et la montée vertigineuse du montant des indemnités versées ont entraîné une hausse de l'utilisation de la transaction à paiements différés. La négociation d'une transaction n'est toutefois pas garante d'une réparation intégrale, et le déséquilibre entre les parties ainsi que le besoin d'indemnisation immédiate de la victime peuvent entraîner la conclusion hâtive d'une transaction. Après un bref survol de l'évolution législative et jurisprudentielle relative au versement d'indemnités par les tribunaux, l'auteur expose la nature et les avantages du mécanisme de la transaction à paiements différés. Il met ensuite en lumière les situations respectives des demandeurs et défendeurs impliqués dans un litige en responsabilité civile pour préjudice corporel et il propose la médiation comme mode de règlement consensuel le plus approprié.The difficulties caused by the granting of a lump-sum payment for bodily injuries have led parties involved in this type of litigation towards a consensual basis for settlement. As such, there has been an increase in the use of deferred payment transactions owing to problems in determining the victim's life expectancy, future rates of inflation, tax impact, the problem inherent with a lump-sum payment in ensuring complete indemnification and the sharp increase in indemnities paid out. The negotiation of a transaction is, however, not a guarantee as to full compensation, and the imbalance between the parties along with the victim's need for immediate indemnification, may lead to the precipitated conclusion of a transaction. Following a brief survey of the evolution in legislative and court decisions regarding indemnity payments, the author explains the nature and advantages of the technique underlying deferred payment transactions. He then draws attention to the respective situations of plaintiffs and defendants involved in civil liability litigations for bodily injuries and he proposes mediation as the most appropriate consensual form of settlement

Computational Tools for Image Processing, Integration, and Visualization of Simultaneous OCT-FLIM Images of Tissue

Multimodal imaging systems have emerged as robust methods for the characterization of atherosclerotic plaques and early diagnosis of oral cancer. Multispectral wide-field Fluorescence Lifetime Imaging Microscopy (FLIM) has been shown to be a capable optical imaging modality for biomedical diagnosis oral cancer. A fiber-based endoscope combined with an intensified charge-coupled device (ICCD) allows to collect and split the fluorescence emission into multiple bands, from which the fluorescence lifetime decay in each spectral channel can be calculated separately. However, for accurate calculations, it is necessary to gather multiple gates increasing the imaging time. Since this time is critical for real-time in vivo applications. This study presents a novel approach to using Rapid Lifetime Determination (RLD) methods to considerably shorten this time period. Moreover, the use of a dual-modality system, incorporating Optical Coherence Tomography (OCT) and FLIM, which simultaneously characterizes 3-D tissue morphology and biochemical composition of tissue, leads to the development of robust computational tools for image processing, integration, and visualization of these imaging techniques. OCTFLIM systems provide 3D structural and 2D biochemical tissue information, which the software tools developed in this work properly integrate to assist the image processing, characterization, and visualization of OCT-FLIM images of atherosclerotic plaques. Additionally, plaque characterization is performed by visual assessment and requires a trained expert for interpretation of the large data sets. Here, we present two novel computational methods for automated intravascular (IV) OCT plaque characterization. The first method is based on the modeling of each A-line of an IV-OCT data set as a linear combination of a number of depth profiles. After estimating these depth profiles by means of an alternating least square optimization strategy, they are automatically classified to predefined tissue types based on their morphological characteristics. The second method is intended to automatically identify macrophage/foam cell clusters in atherosclerotic plaques. Vulnerable plaques are characterized by presenting a necrotic core below a thin fibrous cap, and extensive infiltration of macrophages/foam cells. Thus, the degree of macrophage accumulation is an indicator in determining plaque progression and probability of rupture. In this work, two texture features are introduced, the normalized standard deviation ratio (NSDRatio) and the entropy ratio (ENTRatio), to effectively classify areas in the plaque with macrophage/foam cell infiltration. Since this methodology has low complexity and computational cost, it could be implemented for in vivo real time identification of macrophage/foam cell presence

Ultrastable long-distance frequency dissemination through optical fibres

Nowadays, a large number of applications require highly stable frequency dissemination, such as deep space networks for interferometric imaging with arrays formed by antennas located very far apart. To accomplish this demand for stability, optical fibre links are used due to the advantages of low cost, low attenuation, and immunity to electromagnetic interference. The system studied in this thesis guarantees a high precision among the signals of all the antennas in an array by connecting them coherently in a fibre ring architecture. Through recirculation of a phase conjugated signal, the compensation of the phase instability generated in long distance fibre links by temperature changes and vibrations of the environment is achieved. Nevertheless, the non-idealities of the system?s components may add a random effect in this phase compensation that is analysed using the Allan deviation as a metric factor, with the aim to establish the loss in stability of the frequency dissemination system.Actualmente, un gran número de aplicaciones requieren de una alta estabilidad en la propagación de frecuencia, como las redes del espacio profundo para la interferometría de imagen del cielo con agrupaciones de antenas muy separadas geográficamente. Para satisfacer esta demanda de estabilidad, se usan enlaces de fibra óptica debido a sus ventajas como el bajo precio, baja atenuación e inmunidad a la interferencia electromagnética. El sistema que se estudia en esta tesis garantiza una alta precisión entre las señales de todas las antenas de una agrupación, conectándolas de manera coherente en una arquitectura de anillo de fibra. Por medio de la recirculación de una señal conjugada en fase, se consigue la compensación de la inestabilidad de fase que se genera en los enlaces de fibra largos por los cambios de temperatura y las vibraciones del medio. Sin embargo, las no idealidades de los componentes del sistema pueden añadir un efecto aleatorio a esta compensación de fase, que se analiza usando la desviación de Allan como parámetro de medida con el objetivo de determinar las pérdidas en la estabilidad del sistema de propagación de frecuencia.Actualment, un gran nombre d?aplicacions requereixen d?una alta estabilitat en la propagació de freqüència, com les xarxes de l?espai profund per la interferometria d?imatge del cel amb agrupacions d?antenes molt allunyades geogràficament. Per satisfer aquesta demanda d?estabilitat, s?utilitzen enllaços de fibra òptica degut a avantatges com el seu baix preu, baixa atenuació i immunitat a la interferència electromagnètica. El sistema que s?estudia en aquesta tesi garanteix una alta precisió entre les senyals de totes les antenes d?una agrupació, connectant-les coherentment en una arquitectura d?anell de fibra. Per mitjà de la recirculació d?una senyal conjugada en fase, s?aconsegueix la compensació de la inestabilitat de fase que es genera als enllaços de fibra llargs pels canvis de temperatura i les vibracions del medi. Tanmateix, les no idealitats dels components del sistema poden afegir un efecte aleatori a aquesta compensació de fase, que és analitzat utilitzant la desviació d?Allan com a paràmetre de mesura amb l?objectiu de determinar les pèrdues en l?estabilitat del sistema de propagació de freqüència

Team similarity and favouritism: an exploration of the relationship between different types of similarity with the peers and managers and favouritism

The main purpose of this study is to understand the relationship between the similarity in working groups with the perceived unfairness and justice violation in the workplace (favouritism). This research aims to answer the question of which types of similarity - demographic or perceived – most affects the perception of justice, including different types of justice – distributive, procedural, interpersonal and informational as well as the quality of the relationship developed with the manager – Leader Member Exchange (LMX). Additionally, it is considered that the relationship between similarity and perception of similarity also relates to turnover intention and that the role played by common goals and shared results also impact favouritism and turnover intention in diverse teams. As methodology, questionnaires were distributed (139 participants) in a multinational company with a multicultural environment. The respondents were mainly located in Netherlands, Germany and UK. They were part of teams with three or more members and did not have direct reports. A hierarchical linear regression was applied in order to test the hypotheses. The main results indicate that perceived similarity explains the perception of favouritism whilst demographic similarity has a limited influence explaining the perception of favouritism. Furthermore, the way of organising the work and the shared results in the team contribute to the perception of favouritism. Finally, all the variables that explain favouritism also influence the turnover intention.O principal objectivo deste estudo é perceber a relação entre semelhança nos grupos de trabalho e a percepção de injustiça no local de trabalho (favoritismo). Este estudo pretende ainda identificar quais os tipos de semelhança – demográfica ou percebida – que mais afectam a percepção de diferentes tipos de justiça – distributiva, processual, interpessoal e informacional bem como a qualidade da relação desenvolvida com a chefia – Leader Member Exchange (LMX). Adicionalmente, este trabalho considera que a relação entre semelhança e percepção de semelhança também se relaciona com a intenção de deixar a equipa (turnover intention) e que o papel desempenhado por objectivos colectivos e resultados partilhados tem impacto na percepção de favoritismo e no turnover intention em equipas que apresentam diversidade. Na metodologia foram distribuídos inquéritos (139 participantes) numa empresa multinacional com um ambiente multicultural. Os participantes encontravam-se localizados maioritariamente na Holanda, Alemanha e Inglaterra. Estes participantes integravam equipas com três ou mais membros e não tinham subordinados alocados a si. Para testar as hipóteses foram aplicadas regressões lineares. Os resultados principais indicam que a percepção de semelhança se relaciona com a percepção de favoritismo enquanto a semelhança demográfica tem uma influência limitada na explicação da percepção de favoritismo. Salienta-se que a forma de organizar o trabalho e os prémios nas equipas contribuem para a percepção de favoritismo e que todas as variáveis que explicam o favoritismo também influenciam a intenção de deixar a equipa