Estimative for the size of the compactification radius of a one extra dimension Universe

In this work, we use the Casimir effect to probe the existence of one extra dimension. We begin by evaluating the Casimir pressure between two plates in a $M^4\times S^1$ manifold, and then use an appropriate statistical analysis in order to compare the theoretical expression with a recent experimental data and set bounds for the compactification radius

Instabilities and propagation of neutrino magnetohydrodynamic waves in arbitrary direction

In a previous work [16], a new model was introduced, taking into account the role of the Fermi weak force due to neutrinos coupled to magnetohydrodynamic plasmas. The resulting neutrino-magnetohydrodynamics was investigated in a particular geometry associated with the magnetosonic wave, where the ambient magnetic field and the wavevector are perpendicular. The corresponding fast, short wavelength neutrino beam instability was then obtained in the context of supernova parameters. The present communication generalizes these results, allowing for arbitrary direction of wave propagation, including fast and slow magnetohydrodynamic waves and the intermediate cases of oblique angles. The numerical estimates of the neutrino-plasma instabilities are derived in extreme astrophysical environments where dense neutrino beams exist

Particle creation in a Robertson-Walker Universe revisited

We reanalyze the problem of particle creation in a 3+1 spatially closed Robertson-Walker space-time. We compute the total number of particles produced by this non-stationary gravitational background as well as the corresponding total energy and find a slight discrepancy between our results and those recently obtained in the literatur

Neutrino magnetohydrodynamics

A new neutrino magnetohydrodynamics (NMHD) model is formulated, where the effects of the charged weak current on the electron-ion magnetohydrodynamic fluid are taken into account. The model incorporates in a systematic way the role of the Fermi neutrino weak force in magnetized plasmas. A fast neutrino-driven short wavelengths instability associated with the magnetosonic wave is derived. Such an instability should play a central role in strongly magnetized plasma as occurs in supernovae, where dense neutrino beams also exist. In addition, in the case of nonlinear or high frequency waves, the neutrino coupling is shown to be responsible for breaking the frozen-in magnetic field lines condition even in infinite conductivity plasmas. Simplified and ideal NMHD assumptions were adopted and analyzed in detail

Transformational leadership contributions for employee autonomy

The performance of a company is affected by several variables and understanding them and knowing how they work is decisive for management. Therefore, this research aims to address and measure how transformational leadership impacts the employees work. To test the conceptual model, we used survey data from 174 active workers. Data was analyzed using PLS-SEM. Our results reveal that leaders who adopt a Transformational approach allow workers to be more autonomous in their work, the autonomy leverage the existence of efficiency in tasks and processes. Efficiency is also reached through cost savings, which translates into a reduction of unproductive work time. Furthermore, results indicate the mediating effect of efficiency and employee autonomy on the relation between transformational leadership and cost savings and between transformational leadership and unproductive work time.info:eu-repo/semantics/publishedVersio

Efeitos Cardiovasculares e Respiratórios do Tratamento com Captopril em Ratos Submetidos à Hipertensão Arterial Pulmonar com Monocrotalina

Introdução: A Hipertensão Arterial Pulmonar (HAP) é uma doença caracterizada pelo aumento da resistência arteriolar nos pulmões. Como consequência das alterações arteriolares, ocorre hipóxia que leva à ativação de alguns mecanismos, incluindo os reflexos neurais, respostas ventilatórias e autonômicas, porém estes mecanismos não foram totalmente esclarecidos. Este estudo teve como objetivo avaliar como esses mecanismos são afetados pela HAP induzida pela monocrotalina (MCT) e o possível papel terapêutico do inibidor da enzima conversora da angiotensina (IECA), captopril, na reversão deste processo de remodelamento. Métodos e Resultados: Grupos de ratos Wistar foram tratados com uma injeção subcutânea de MCT (60 mg.kg-1) para indução da HAP. Três semanas depois, estes animais receberam captopril (CPT, 100 mg.kg-1) na sua água de beber (grupo MCT-CPT) ou apenas água (grupo MCT) durante 2 semanas. Como controle, outro grupo de animais foram tratados com solução salina e receberam captopril na água de beber (grupo CPT) ou água pura (grupo CON), também durante 2 semanas. Os resultados mostraram que a HAP foi totalmente induzida no grupo MCT, evidenciada por uma elevação do índice pulmonar. A análise gasométrica e respiratória evidenciaram a ocorrência de hipoxemia e hiperventilação compensatória. O tratamento com captopril dos animais com HAP normalizou estes parâmetros em comparação com o grupo CON. Observou-se também uma significante disfunção autonômica no grupo MCT, a qual foi revertida após o tratamento com captopril. Finalmente, as análises dos reflexos cardiovasculares evidenciaram uma exacerbação das respostas do quimiorreflexo no grupo MCT, enquanto a sensibilidade do barorreflexo e do reflexo Bezold-Jarisch reduziu expressivamente. Surpreendentemente, o tratamento com captopril normalizou essas respostas reflexas a valores semelhantes ao grupo CON. Conclusões: O presente estudo demonstrou que a HAP induzida por MCT induz respostas respiratórias compensatórias, disautonomia, disfunção do barorreflexo e do reflexo Bezold-Jarisch e exacerbação das respostas quimiorreflexas. Os dados também indicam que o tratamento com captopril foi eficaz em reverter estes distúrbios cardio-respiratórios, sugerindo que o uso de drogas ACEI pode ter um grande potencial terapêutico para a HAP. Palavras-chave: hipertensão arterial pulmonar, monocrotalina, captopril, quimiorreflexo, barorreflexo, reflexo Bezold-Jarisch

Study on the association between sleep disorders versus oral health related variables

To study the association between sleep quality and oral health related variables, which still have conflicts in the literature. This was a population-based case-control study between subjects with versus without sleep disorders from the Brazilian Public Health System (SUS), city of Maringá (N=1,643). Subjects answered self-reported questionnaires: a) Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD), b) Sleep Assessment Questionnaire (SAQ) and c) North York Dental Health Survey (NYDHS). No significant difference was found for gender, marital status, or income; however, non-Caucasians, people with lower levels of education, and those between 20 to 50 years old had worse scores of sleep disorders in the SAQ. Self-perceived oral health, masticatory capacity to eat foods, and gingival bleeding was significantly worse among subjects with self-reported sleep disorders. Self-reported tooth loss, edentulism and use of removable partial dentures (with clasps) or complete dentures showed no significant difference between groups. Self-reported sleep disorder subjects presented significantly higher prevalence of both self-reported tooth and TMJ pain. It can be concluded that individuals with self-reported sleep disorders presented worse self-perceived oral health for most studied variables

Dynamical Casimir effect for a massless scalar field between two concentric spherical shells

In this work we consider the dynamical Casimir effect for a massless scalar field -- under Dirichlet boundary conditions -- between two concentric spherical shells. We obtain a general expression for the average number of particle creation, for an arbitrary law of radial motion of the spherical shells, using two distinct methods: by computing the density operator of the system and by calculating the Bogoliubov coefficients. We apply our general expression to breathing modes: when only one of the shells oscillates and when both shells oscillate in or out of phase. We also analyze the number of particle production and compare it with the results for the case of plane geometry.Comment: Final version. To apear in Physical Review

Factors Associated with Marburg Hemorrhagic Fever:

Background. Reliable on-site polymerase chain reaction (PCR) testing for Marburg hemorrhagic fever (MHF) is not always available. Therefore, clinicians triage patients on the basis of presenting symptoms and contact history. Using patient data collected in Uige, Angola, in 2005, we assessed the sensitivity and specificity of these factors to evaluate the validity of World Health Organization (WHO)–recommended case definitions for MHF. Methods. Multivariable logistic regression was used to identify independent predictors of PCR confirmation of MHF. A data-derived algorithm was developed to obtain new MHF case definitions with improved sensitivity and specificity. Results. A MHF case definition comprising (1) an epidemiological link or (2) the combination of myalgia or arthralgia and any hemorrhage could potentially serve as an alternative to current case definitions. Our dataderived case definitions maintained the sensitivity and improved the specificity of current WHO-recommended case definitions. Conclusions. Continued efforts to improve clinical documentation during filovirus outbreaks would aid in the refinement of case definitions and facilitate outbreak control