A Generalization of the Goldberg-Sachs Theorem and its Consequences

The Goldberg-Sachs theorem is generalized for all four-dimensional manifolds endowed with torsion-free connection compatible with the metric, the treatment includes all signatures as well as complex manifolds. It is shown that when the Weyl tensor is algebraically special severe geometric restrictions are imposed. In particular it is demonstrated that the simple self-dual eigenbivectors of the Weyl tensor generate integrable isotropic planes. Another result obtained here is that if the self-dual part of the Weyl tensor vanishes in a Ricci-flat manifold of (2,2) signature the manifold must be Calabi-Yau or symplectic and admits a solution for the source-free Einstein-Maxwell equations.Comment: 14 pages. This version matches the published on

Avaliação da amplitude articular do joelho: correlação entre as medidas realizadas com o goniômetro universal e no dinamômetro isocinético

CONTEXTUALIZAÇÃO: O instrumento mais utilizado pelos terapeutas para mensuração da amplitude de movimento (ADM) articular é o goniômetro universal. No entanto, há carência de estudos que analisem a confiabilidade das medidas da ADM do joelho realizadas no dinamômetro isocinético. OBJETIVO: O objetivo deste estudo foi analisar a correlação entre as medidas de ADM na articulação do joelho, realizadas com o goniômetro universal e no dinamômetro isocinético. MÉTODO: Foram avaliados 38 voluntários saudáveis (27 mulheres, 11 homens), com idade de 36 ± 11 anos, com limitação mínima de 20° na ADM de extensão do joelho. No membro dominante de cada sujeito foram realizadas três mensurações da ADM do joelho com o goniômetro e três mensurações no dinamômetro. RESULTADOS: Os resultados deste estudo mostraram que há alto grau de correlação entre as medidas da ADM do joelho obtidas com o goniômetro universal e no dinamômetro isocinético (Coeficiente de Correlação de Pearson = 0,90). CONCLUSÃO: Com os procedimentos realizados, tanto o goniômetro universal como o dinamômetro isocinético podem ser utilizados para avaliação da ADM do joelho, pois ambos apresentam mensurações confiáveis.<br>BACKGROUND: The instrument most often used by therapists for measuring joint range of motion (ROM) is the universal goniometer. However, there is a lack of studies analyzing the reliability of knee joint ROM measured by the isokinetic dynamometer. OBJECTIVE: The purpose of this study was to analyze the correlation between the knee joint ROM measurements made using a universal goniometer and an isokinetic dynamometer. METHOD: 38 healthy volunteers (27 women, 11 men) aged 36 ± 11 years were evaluated. All of them had a minimum knee extension ROM limitation of 20°. Three knee ROM measurements were made using the universal goniometer and another three using the isokinetic dynamometer, on each subject's dominant limb. RESULTS: The results showed a high degree of correlation between the knee ROM measurements made using the two instruments (Pearson correlation coefficient = 0.90). CONCLUSION: From the procedures performed, both the universal goniometer and the isokinetic dynamometer can be used to evaluate knee ROM, since they both present reliable measurements

Presenteeism in hospital nurses

This quantitative, descriptive, cross-sectional research aimed to determine the estimated productivity of health-related limitations at work in 129 nurses working in direct care delivery to critical and potentially critical patients. Instruments were applied for socio-demographic and functional characterization and for the evaluation of presenteeism (Work Limitations Questionnaire). Statistical Package for the Social Sciences software was used for data analysis. In this study, 75% of nurses obtained a lost productivity index of up to 4.84%. The physical demand domain represented the major limitation for these professionals (25%). Presenteeism was directly correlated to health care, occurrence and number of absences, and indirectly related to work time at the unit. It was concluded that organizational or individual factors influence individuals' productivity, in view of the circumstances involving care delivery to critical and potentially critical patients.Estudio cuantitativo, descriptivo y transversal con el objetivo de determinar la productividad supuesta de las limitaciones en el trabajo relacionadas con la salud de 129 enfermeros que asisten a pacientes críticos y potencialmente críticos. Se utilizó un instrumento para la caracterización sociodemográfica y funcional y para la evaluación de la presencia. Se realizó un análisis estadístico de los datos con el software Statistical Package for the Social Sciences. En este estudio, 75 % de los enfermeros obtuvieron un índice de productividad perdida de hasta 4,84%. La demanda física fue el dominio que presentó mayor limitación (25%). La presencia se relacionó directamente a: realización de tratamiento de salud, ocurrencia y número de faltas, e indirectamente al tiempo en la unidad. Se concluye que existe influencia de factores organizacionales o individuales en la productividad del individuo frente a las circunstancias que involucran la asistencia al paciente crítico y potencialmente crítico.Este é um estudo quantitativo, descritivo e transversal com o objetivo de determinar a produtividade estimada das limitações no trabalho, relacionadas à saúde, em 129 enfermeiros atuantes na assistência direta a pacientes críticos e potencialmente críticos. Utilizou-se instrumento para caracterização sociodemográfica e funcional e para a avaliação do presenteísmo (questionário de limitações no trabalho). Procedeu-se à análise estatística dos dados com o software Statistical Package for the Social Sciences. Neste estudo, 75% dos enfermeiros obtiveram índice de produtividade perdida de até 4,84%. A demanda física foi o domínio que representou maior limitação para esses profissionais (25%). O presenteísmo correlacionou-se diretamente à realização de tratamento de saúde, ocorrência e número de faltas, e indiretamente ao tempo de trabalho na unidade. Conclui-se que existe influência de fatores organizacionais ou individuais na produtividade do indivíduo, frente às circunstâncias que envolvem a assistência ao paciente crítico e potencialmente crítico

Trypanosoma vivax Infections: Pushing Ahead with Mouse Models for the Study of Nagana. I. Parasitological, Hematological and Pathological Parameters

African trypanosomiasis is a severe parasitic disease that affects both humans and livestock. Several different species may cause animal trypanosomosis and although Trypanosoma vivax (sub-genus Duttonella) is currently responsible for the vast majority of debilitating cases causing great economic hardship in West Africa and South America, little is known about its biology and interaction with its hosts. Relatively speaking, T. vivax has been more than neglected despite an urgent need to develop efficient control strategies. Some pioneering rodent models were developed to circumvent the difficulties of working with livestock, but disappointedly were for the most part discontinued decades ago. To gain more insight into the biology of T. vivax, its interactions with the host and consequently its pathogenesis, we have developed a number of reproducible murine models using a parasite isolate that is infectious for rodents. Firstly, we analyzed the parasitical characteristics of the infection using inbred and outbred mouse strains to compare the impact of host genetic background on the infection and on survival rates. Hematological studies showed that the infection gave rise to severe anemia, and histopathological investigations in various organs showed multifocal inflammatory infiltrates associated with extramedullary hematopoiesis in the liver, and cerebral edema. The models developed are consistent with field observations and pave the way for subsequent in-depth studies into the pathogenesis of T. vivax - trypanosomosis

Ferroelectric nanofibers with an embedded optically nonlinear benzothiazole derivative

We report measurements of the molecular first hyperpolarizability, thermal stability, photophysical, piezoelectric and ferroelectric properties of a benzothiazole derivative bearing an arylthiophene π-conjugated bridge both in solution and when embedded into a poly (L-lactic acid) (PLLA) matrix in the form of electrospun fibers with an average diameter of roughly 500 nm. The embedded nanocrystalline phenylthienyl-benzothiazole derivative, with crystal sizes of about 1.4 nm resulted in a good piezoelectric response from these functionalized electrospun fibers, indicative of a polar crystalline structure.Fundação para a Ciência e a Tecnologia (FCT