Assessing the Role of Longitudinal Variability of Vertical Track Stiffness in the Long-Term Deterioration

The performance of the railway system in terms of dynamic loading is depending mainly on the track support conditions. Usually, the track stiffness is used as the main parameter to describe the support conditions and is defined as the ratio of the load applied to the rail over the vertical rail deflection. Ideally that parameter is constant, but in reality this condition is very unlikely to happen. Therefore, there is non-uniform track loading and non-uniform track deterioration, generally known as differential settlement, leading to a general increment of maintenance and renewal costs. Even if it plays a major role in the system dynamics, it is very difficult to derive a measure of the actual variability of the track stiffness along the railway. There are many techniques to experimentally acquire those values, for example using the Falling Weight Deflectometer (FWD) equipment or the Swedish Rolling Stiffness Measurement Vehicle (RSDV) measuring train. However, these measures are usually very costly and limited in extension. The measuring data may not be long enough to be statistically representative, and thus it is not possible to have a clear correlation between the physical properties of the railway system and its long-term behaviour without running simulations with extended track data. The main aim of the present study is to assess the role of longitudinal variability of the vertical track stiffness in the long-term behaviour of the track degradation. In particular, new sets of track stiffness data which can appropriately reproduce the statistical properties of the real ones will be simulated. Then, the variability of the outputs of the vehicle dynamic model depending on the variability in the inputs will be statistically analysed. This is inspired in past research that highlighted the role of vertical stiffness in track deterioration, but not looking at the actual longitudinal variability of vertical stiffness as a contributing factor

A influência do genoma humano no curso das hepatites virais crônicas

The mechanisms that determine viral clearance or viral persistence in chronic viral hepatitis have yet to be identified. Recent advances in molecular genetics have permitted the detection of variations in immune response, often associated with polymorphism in the human genome. Differences in host susceptibility to infectious disease and disease severity cannot be attributed solely to the virulence of microbial agents. Several recent advances concerning the influence of human genes in chronic viral hepatitis B and C are discussed in this article: a) the associations between human leukocyte antigen polymorphism and viral hepatic disease susceptibility or resistance; b) protective alleles influencing hepatitis B virus (HBV) and hepatitis C virus (HCV) evolution; c) prejudicial alleles influencing HBV and HCV; d) candidate genes associated with HBV and HCV evolution; d) other genetic factors that may contribute to chronic hepatitis C evolution (genes influencing hepatic stellate cells, TGF-beta1 and TNF-alpha production, hepatic iron deposits and angiotensin II production, among others). Recent discoveries regarding genetic associations with chronic viral hepatitis may provide clues to understanding the development of end-stage complications such as cirrhosis or hepatocellular carcinoma. In the near future, analysis of the human genome will allow the elucidation of both the natural course of viral hepatitis and its response to therapy.Os mecanismos que determinam o clearance ou a persistência da infecção viral nas hepatites virais crônicas não estão ainda bem identificados. O progresso no conhecimento sobre as ferramentas genéticas moleculares tem permitido detectar variações na resposta imune, que freqüentemente são associadas com polimorfismos do genoma humano. As diferenças na susceptibilidade do hospedeiro para as doenças infecciosas e a intensidade das doenças não podem ser atribuídas apenas à virulência do agente microbiano. Neste artigo são discutidos vários avanços recentes no conhecimento sobre a influência dos genes humanos nas hepatites crônicas B e C, a saber: a) As associações entre os polimorfismos HLA e a susceptibilidade ou resistência às doenças hepáticas virais; b) Alelos protetores influenciando as hepatites virais B (HVB) e C (HVC); c) Alelos prejudiciais influenciando HVB e HVC; d) Genes candidatos associados com a evolução clínica de HVB e HVC (genes que influenciam as células estreladas do fígado, a produção de TGF-beta1 e TNF-alfa, os depósitos de ferro hepáticos, a produção de angiotensina II, entre outros). O conhecimento das associações genéticas com as hepatites virais crônicas pode fornecer indícios para o pleno entendimento de como se desenvolvem as suas complicações terminais, como a cirrose e o carcinoma hepatocelular. Em futuro próximo, a análise do genoma humano será capaz de elucidar o curso natural de uma hepatite viral, bem como a sua resposta à terapêutica

Collective rearrangement at the onset of flow of a polycrystalline hexagonal columnar phase

Creep experiments on polycrystalline surfactant hexagonal columnar phases show a power law regime, followed by a drastic fluidization before reaching a final stationary flow. The scaling of the fluidization time with the shear modulus of the sample and stress applied suggests that the onset of flow involves a bulk reorganization of the material. This is confirmed by X-ray scattering under stress coupled to \textit{in situ} rheology experiments, which show a collective reorientation of all crystallites at the onset of flow. The analogy with the fracture of heterogeneous materials is discussed.Comment: to appear in Phys. Rev. Let

Measurement of peripheral blood mononuclear cells producing IFN-Gamma in patients with tuberculosis

The type of immune response induced by tuberculosis (Th1 or Th2) and its correlation with the clinical outcome is unclear. We studied 13 patients with active tuberculosis (TBC). The peripheral blood mononuclear cells producing IFN-gamma (PBMC-IG) were measured by enzyme-linked immunospot (ELISPOT) technique. The control group had ten healthy individuals vaccinated against tuberculosis. We collected blood samples of each patient in two moments: a) in the hospital admission without treatment (TBC1); b) after seven to 20 days of treatment (TBC2). The comparison of the spots forming units of PBMC-IG between TBC group and controls showed that there was a significant difference between TBC1 and control group (p < 0.001) and between TBC2 and control group (p < 0.005), but there was no difference between TBC1 and TBC2 (p > 0.05). A positive correlation was found between PBMC-IG and hemoglobin value, as well as between PBMC-IG and weight loss. There was no correlation between PBMC-IG and other variables [age, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP)]. We conclude that tuberculosis activates Th1 immune response due to increase of PBMC producing IFN-gamma. There was no difference between the first sample (TBC1) and the second sample (TBC2) of PBMC-IG. This result can have occurred due to treatment influence, or can indicate that the immune response reachs a plateau. The positive correlation among PBMC-IG and both hemoglobin level and weight loss indicates that may exist a link between patient's clinical status and the immune response intensity.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Modelling the protein-energy malnourished stroke patient

Little is known about the effects of protein-energy malnutrition (PEM) developing after stroke on brain recovery. The goal of this project was to develop two experimental models in the adult rat to allow evaluation of nutritional effects on post-stroke recovery: (1) a PEM model, and (2) a photothrombotic stroke model. Experiment 1 examined the hypothesis that a diet containing either 1% or 0.5% protein will produce an acute state of mild-moderate PEM in adult rats. Male, Sprague-Dawley rats (16 wk) were trained in the Montoya staircase before being randomized to diets containing 0.5% (n=8), 1% (n=8), or 12.5% protein (n=10 [CON]) for 31d. Both low protein diets increased liver lipid content (p< 0.001) and decreased food intake (p= 0.005) and body weight (p< 0.001) compared to the 12.5% protein diet. The 0.5% protein group best mimicked the stroke patient, as judged by decreased serum albumin (p= 0.018) and an acute decrease in mean (±SEM) body weight (g) by d7 (0.5%= 424±15; 1%= 428±14; CON= 477±10; p = 0.011). Increased concentrations of the positive acute phase proteins, alpha-2-macroglobulin and alpha-1-acid glycoprotein, were greatest in the 0.5% group (p< 0.001). No differences were observed in the Montoya test on d3, 15, or 30 (p= 0.26). Values on d30 were: 0.5%= 109.5±4.4% of pre-diet performance; 1%= 97.2±5.5%; CON= 98.5±10.2%. Experiment 2 tested the hypothesis that targeted laser irradiation and 30 mg/kg of rose Bengal injection will cause an infarct in the forepaw region of the cortex with accompanying functional deficits. Male adult rats trained in the Montoya staircase were randomized to ISCHEMIA (n=15) or SHAM (n=3) surgery. A cortical infarct occurred in 86% of rats, with some misplacement and variability in volume (5.7-12.8 mm3). Forepaw impairments were confirmed by decreased performance in the staircase at d3 (34.3±7.3 % of pre-stroke performance, p<0.001) and diminished use in the cylinder test (30.3±4.0% affected limb use versus 53.9±1.93% prestroke, p< 0.001). At d30, mean recovery was incomplete in the staircase (p< 0.001). These experimental models, with additional refinements, can be used to address the hypothesis that deteriorating nutritional status after a stroke interferes with brain recovery

La economía del parto : interfaces de la agenda neoliberal y de la lucha feminista por la humanización de la asistencia al parto

Una revisión atenta de la literatura sobre el proceso de medicalización e higienización en Francia y Brasil entre el fin del siglo XIX y comienzos del siglo XX demuestra que la entrada de los médicos en el campo de la asistencia al parto se dio con la colaboración del movimiento feminista. Ya entre los años 1920 y 1940, observamos una serie de técnicas y discursos elaborados por médicos disidentes en Rusia y Gran Bretaña que crearon las bases para el surgimiento de un movimiento global de mujeres por la reforma de los servicios de maternidad, conocido hoy como Movimiento por la Humanización del Parto y Nacimiento. Un análisis de la emergencia del discurso de la "Humanización del Parto" como "Legitimidad de una práctica basada en evidencias" permitió́ identificar la relación entre el desarrollo de nuevas técnicas corporales, conceptos y protocolos y la entrada del Banco Mundial en el diseño de políticas para el campo de la salud. En este trabajo se presenta una síntesis de una conferencia sobre un proyecto de tesis que pretende aclarar mejor estas cuestiones.A careful review of the literature about the process of medicalization and sanitation in France and Brazil between the late nineteenth century and early twentieth century shows that the entry of doctors in the field of midwifery occurred with the collaboration of the feminist movement. Between 1920 and 1940, we observed a number of technical and speeches elaborated by dissident doctors in Russia and Britain that created the foundation for the emergence of a global women's movement for the reform of maternity services, known today as the Movement for the Humanization of Childbirth. An analysis of the emergence of the discourse of "humanization of childbirth" and "Legitimacy of evidence-based practice" identified the relationship between the development of new physical techniques, concepts and protocols and the entrance to the World Bank in policy design in the field of health. In this paper presents a synthesis of a conference in which i present a thesis project which aims to clarify these issues better