84 research outputs found

    A Stealth Supersymmetry Sampler

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    The LHC has strongly constrained models of supersymmetry with traditional missing energy signatures. We present a variety of models that realize the concept of Stealth Supersymmetry, i.e. models with R-parity in which one or more nearly-supersymmetric particles (a "stealth sector") lead to collider signatures with only a small amount of missing energy. The simplest realization involves low-scale supersymmetry breaking, with an R-odd particle decaying to its superpartner and a soft gravitino. We clarify the stealth mechanism and its differences from compressed supersymmetry and explain the requirements for stealth models with high-scale supersymmetry breaking, in which the soft invisible particle is not a gravitino. We also discuss new and distinctive classes of stealth models that couple through a baryon portal or Z' gauge interactions. Finally, we present updated limits on stealth supersymmetry in light of current LHC searches.Comment: 45 pages, 16 figure

    Examining ecological validity in social interaction: problems of visual fidelity, gaze, and social potential

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    Social interaction is an essential part of the human experience, and much work has been done to study it. However, several common approaches to examining social interactions in psychological research may inadvertently either unnaturally constrain the observed behaviour by causing it to deviate from naturalistic performance, or introduce unwanted sources of variance. In particular, these sources are the differences between naturalistic and experimental behaviour that occur from changes in visual fidelity (quality of the observed stimuli), gaze (whether it is controlled for in the stimuli), and social potential (potential for the stimuli to provide actual interaction). We expand on these possible sources of extraneous variance and why they may be important. We review the ways in which experimenters have developed novel designs to remove these sources of extraneous variance. New experimental designs using a ‘two-person’ approach are argued to be one of the most effective ways to develop more ecologically valid measures of social interaction, and we suggest that future work on social interaction should use these designs wherever possible

    Balance of IL-10 and Interferon-γ plasma levels in human visceral leishmaniasis: Implications in the pathogenesis

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    BACKGROUND: Leishmaniasis remains a serious public health problem in several parts of the developing world. Effective prophylactic measurements are hampered by imprecise comprehension of different aspects of the disease, including its immunoregulation. A better comprehension of immunoregulation in human VL may be useful both for designing and evaluating immunoprophylaxis. METHODS: To explore immunoregulatory mechanisms, 20 visceral leishmaniasis (VL) patients were evaluated during active disease and at different periods up to one year after treatment determining their plasma cytokine levels, clinical parameters (palpable spleen and liver) and antibody levels. RESULTS: Elevated plasma levels of IFN-γ and of IL-12 p40 were observed during active disease, significantly decreasing after treatment whereas in vitro Leishmania antigen-stimulated IFN-γ production by PBMC exhibited an inverse pattern being low during disease and increasing steadily thereafter. Absence of IFN-γ activity is a hallmark of VL. The main candidate for blunting IFN-γ activity is IL-10, a cytokine highly elevated in plasma with sharp decrease after treatment. Activity of IL-10 is inferred by high levels of anti-Leishmania specific IgG1 and IgG3. TGF-β had elevated total, but not of active, levels lessening the likelihood of being the IFN-γ counterpart. Spleen or liver size presented a steady decrease but return to normal values at only 120 days after treatment. Anti-Leishmania IgG (total and subclasses) levels and DTH or Leishmania-stimulated lymphocyte proliferation conversion to positive also present a slow decrease after treatment. IL-6 plasma levels were elevated in only a few patients. CONCLUSION: Taken together our results suggest that IFN-γ and IL-10 are the molecules most likely involved in determining fate of disease. After treatment, there is a long delay before the immune profile returns to normal what precludes using plasma cytokine levels as criteria of cure as simpler clinical evaluations, as a palpable spleen or liver, can be used

    Acurácia do relacionamento probabilístico na avaliação da alta complexidade em cardiologia

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    OBJETIVO: Evaluar la viabilidad de estrategia de relación probabilística en la identificación de pacientes sometidos a procedimientos de alta complejidad en cardiología. MÉTODOS: El costo de procesamiento fue calculado con base en 1.672 registros de pacientes sometidos a cirugía de revascularización del miocardio, relacionados con todos los registros de óbito en Brasil en 2005. La precisión de la relación se basó en linkage probabilística de 99 registros de autorización de internación hospitalaria de pacientes sometidos a cirugías cardíacas en instituto de referencia en cardiología, con status vital conocido, con todos los registros de óbito del estado de Rio de Janeiro en 2005. El linkage fue realizado en cuatro etapas: estandarización de las bases, blocaje, pareamiento y clasificación de los pares. Se utilizó blocaje en cinco pasos, con claves de blocaje con combinación de variables como soundex del primero y último nombre, sexo y año de nacimiento. Las variables utilizadas en el pareamiento fueron "nombre completo", con la utilización de la distancia de Levenshtein y "fecha de nacimiento". RESULTADOS: El segundo y el quinto pasos de blocaje tuvieron los mayores números de pares formados y los mayores tiempos de procesamiento para el pareamiento. El cuarto paso demandó menor costo de procesamiento. En el estudio de precisión, posterior a cinco pasos de blocaje, la sensibilidad del linkage fue de 90,6% y la especificidad fue de 100%. CONCLUSIONES: La estrategia de relación probabilística utilizada presenta buena precisión y podrá ser utilizada en estudios sobre la efectividad de los procedimientos de alta complejidad y alto costo en cardiología.OBJECTIVE: To evaluate the viability of a probabilistic record linkage strategy to identify patients who underwent complex cardiology procedures among the total deceased population. METHODS: The processing cost was estimated based on 1,672 records of patients undergoing coronary artery bypass grafting that were compared with all death records in Brazil in 2005. The accuracy of the linkage strategy was based on the probabilistic linkage of 99 hospital admissions records of patients, with known vital status, who underwent cardiac surgery at a single cardiology institute, with the death records of the state of Rio de Janeiro, Southeastern Brazil, in 2005. Linkage was conducted in four stages: standardizing the databases, blocking, matching, and rating peers. Blocking in five steps was used, with blocking keys formed by a combination of variables such as soundex codes for the first and last names, sex, and year of birth. The variables used for matching were "full name" with the use of Levenshtein distance and "birth date". RESULTS: The second and fifth blocking steps resulted in the largest number of formed pairs and the largest processing times for the matching. The fourth step required a lower processing cost. In the accuracy study, after five blocking steps, the sensitivity of the linkage was 90.6%, and the specificity was 100%. CONCLUSIONS: The probabilistic strategy used has high accuracy and can be used in studies of the effectiveness of high-complexity, high-cost cardiology procedures.OBJETIVO: Avaliar a viabilidade de estratégia de relacionamento probabilístico de bases de dados na identificação de óbitos de pacientes submetidos a procedimentos de alta complexidade em cardiologia. MÉTODOS: O custo de processamento foi estimado com base em 1.672 registros de pacientes submetidos à cirurgia de revascularização do miocárdio, relacionados com todos os registros de óbito no Brasil em 2005. A acurácia do relacionamento baseou-se em linkage probabilístico entre 99 registros de autorização de internação hospitalar de pacientes submetidos a cirurgias cardíacas em instituto de referência em cardiologia, com status vital conhecido, e todos os registros de óbito do estado do Rio de Janeiro em 2005. O linkage foi realizado em quatro etapas: padronização das bases, blocagem, pareamento e classificação dos pares. Utilizou-se a blocagem em cinco passos, com chaves de blocagem com combinação de variáveis como soundex do primeiro e último nome, sexo e ano de nascimento. As variáveis utilizadas no pareamento foram "nome completo", com a utilização da distância de Levenshtein, e "data de nascimento". RESULTADOS: O segundo e o quinto passos de blocagem tiveram os maiores números de pares formados e os maiores tempos de processamento para o pareamento. O quarto passo demandou menor custo de processamento. No estudo de acurácia, após os cinco passos de blocagem, a sensibilidade do linkage foi de 90,6% e a especificidade foi de 100%. CONCLUSÕES: A estratégia de relacionamento probabilístico utilizada apresenta boa acurácia e poderá ser utilizada em estudos sobre a efetividade dos procedimentos de alta complexidade e alto custo em cardiologia

    High-Performance Work Systems and Organizational Performance in Emerging Economies: Evidence from MNEs in Turkey

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    This study examines the association between the usage of high-performance work systems (HPWS) by subsidiaries of multinational enterprises (MNEs) in Turkey and employee and subsidiary level outcomes. The study is based on a survey of 148 MNE subsidiaries operating in Turkey. The results show that the usage of HPWS has a significant positive impact on employee effectiveness. However, their impact on employee skills and development, and organizational financial performance are far less clear. Our findings highlight the extent to which HWPS need to be adapted to take account of context-specific institutional realities. © 2014 Springer-Verlag Berlin Heidelberg
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