Phenotypic and Functional Characterization of Human Memory T Cell Responses to Burkholderia pseudomallei

The Gram-negative bacterium, Burkholderia pseudomallei, is a public health problem in southeast Asia and northern Australia and a Centers for Disease Control and Prevention listed Category B potential bioterrorism agent. It is the causative agent of melioidosis, and clinical manifestations vary from acute sepsis to chronic localized and latent infection, which can reactivate decades later. B. pseudomallei is the major cause of community-acquired pneumonia and septicemia in northeast Thailand. In spite of the medical importance of B. pseudomallei, little is known about the mechanisms of pathogenicity and the immunological pathways of host defense. There is no available vaccine, and the mortality rate in acute cases can exceed 40% with 10–15% of survivors relapsing or being reinfected despite prolonged and complete treatments. In this article, we describe cell-mediated immune responses to B. pseudomallei in humans living in northeast Thailand and demonstrate clear evidence of T cell priming in healthy seropositive individuals and patients who recovered from melioidosis. This is the most detailed study yet performed on the cell types that produce interferon-gamma to B. pseudomallei in humans and the antigens that they recognize and the first to study large sample numbers in the primary endemic focus of melioidosis in the world

One size fits all? High frequency trading, tick size changes and the implications for exchanges: market quality and market structure considerations

This paper offers a systematic review of the empirical literature on the implications of tick size changes for exchanges. Our focus is twofold: first, we are concerned with the market quality implications of a change in the minimum tick size. Second, we are interested in the implications of changes in the minimum tick size on market structure. We show that there is a large body of empirical literature that documents a decrease in transaction costs following a decrease in the minimum tick size. However, even though market liquidity increases, the incentive to provide market making activities decreases. We document a strong link between the minimum tick size regulations and the recent increase in high frequency trading activity. A smaller tick enhances the price discovery process. However, the question of how multiple tick size regimes affect market liquidity in a fragmented market remains to be answered. Finally, we identify topics for future research; we discuss the empirical literature on the minimum trade unit and the recent calls for a minimum resting time for quotes

A Multi-model Approach to Analyse Railway Track-Ground Dynamics and Soil Nonlinearity

An increase in train speed generates amplified track deflection. With higher speed, larger strains are induced within the track and subgrade structures. This results in nonlinear behaviour of material properties, particularly the soil stiffness. In railway engineering, it is challenging to deal with these high levels of amplification because the deep wave propagation within the track and underlying soil structures is complicated. Therefore, this paper investigates the influential variables that cause a significant impact on the dynamic amplification of the railway. Four modelling strategies used to generate findings into the problems of railway track dynamics and track-soil nonlinearity. The four types of model are analytical, combined analytical–numerical, 2.5D finite element and 3D finite element. These four models are used to analyse the cases of homogenous half-space soils, homogenous soils above bedrock, layered soils, low-stiffness soil layers and track-soil nonlinearity. The analysis results provide a better understanding of wave propagation characteristics within the subgrade structures. This can be useful for consideration of the design or improvement of railway track structures and earthworks