Tainted Benevolence: Sources of Funding for the Liverpool School of Tropical Medicine from 1898-1915

The final two decades of the nineteenth century saw a race among European powers to secure vast tracts of land in Africa for colonization and exploitation. However, the empires of the West soon found that effective occupation of this new continent would not end with a physical takeover. In order to benefit politically and financially from their new territories, colonial governments would have to confront a series of unforeseen challenges, one of the largest of which was the prevalence of so-called tropical diseases. Few doctors in Europe had any experience with or understanding of conditions from sleeping sickness to Guinea worm that ravaged settlers and natives alike in the “Dark Continent.” Thus, in 1898 a new school of medicine was founded in Great Britain with the noble mission of expanding knowledge of this new class of illnesses and saving lives in Africa and other newly colonized regions. Yet over its first seventeen years of operation, the Liverpool School of Tropical Medicine continually accepted large donations from individuals whose interests certainly did not lie with humanitarian or scientific gain. This paper examines how the personal investments of the Liverpool School\u27s donors impacted the direction of its efforts, and ultimately tainted its magnanimous aims

Tuberculosis and Poor Health Among Migrant and Seasonal Farmworkers in the United States

The following paper will explore the prevalence of TB among migrant and seasonal farmworkers in the United States, and the systemic forces that contribute to that prevalence. Cyclical of poverty, dangerous working conditions, and barriers to healthcare overall have all led to increased risk of TB infection for farmworkers and their families. Moreover, structural violence traps these farmworkers in conditions of increased risk that have a major impact on their general health. Thus, the issue of TB is not a single issue, but one that relates to a range of social, economic, and political factors. Improving TB outcomes for farmworkers will require a dramatic reimagining of our agricultural labor system, and increased investment in the wellbeing of these essential workers

Volunteering and well-being : do self-esteem, optimism, and perceived control mediate the relationship?

Volunteers play a vital role in modern societies by boosting the labor force within both the public and private sectors. While the factors that may lead people to volunteer have been investigated in a number of studies, the means by which volunteering contributes to the well-being of such volunteers is poorly understood. It has been suggested through studies that focus on the absence of depression in volunteers that self-esteem and sense of control may be major determinants of the increased well-being reported by volunteers. This is consistent with the homeostatic model of subjective well-being, which proposes that self-esteem, optimism, and perceived control act as buffers that mediate the relationship between environmental experience and subjective well-being (SWB). Using personal well-being as a more positive measure of well-being than absence of depression, this study further explored the possible mediating role of self-esteem, optimism, and perceived control in the relationship between volunteer status and well-being. Participants (N = 1,219) completed a 97-item survey as part of the Australian Unity Wellbeing project. Variables measured included personal well-being, self-esteem, optimism, and a number of personality and psychological adjustment factors. Analyses revealed that perceived control and optimism, but not self-esteem, mediated the relationship between volunteer status and personal well-being.<br /

SPH with the multiple boundary tangent method

In this article, we present an improved solid boundary treatment formulation for the smoothed particle hydrodynamics (SPH) method. Benchmark simulations using previously reported boundary treatments can suffer from particle penetration and may produce results that numerically blow up near solid boundaries. As well, current SPH boundary approaches do not properly treat curved boundaries in complicated flow domains. These drawbacks have been remedied in a new boundary treatment method presented in this article, called the multiple boundary tangent (MBT) approach. In this article we present two important benchmark problems to validate the developed algorithm and show that the multiple boundary tangent treatment produces results that agree with known numerical and experimental solutions. The two benchmark problems chosen are the lid-driven cavity problem, and flow over a cylinder. The SPH solutions using the MBT approach and the results from literature are in very good agreement. These solutions involved solid boundaries, but the approach presented herein should be extendable to time-evolving, free-surface boundaries

Kelvin-Helmholtz instabilities in Smoothed Particle Hydrodynamics

In this paper we investigate whether Smoothed Particle Hydrodynamics (SPH), equipped with artificial conductivity, is able to capture the physics of density/energy discontinuities in the case of the so-called shearing layers test, a test for examining Kelvin-Helmholtz (KH) instabilities. We can trace back each failure of SPH to show KH rolls to two causes: i) shock waves travelling in the simulation box and ii) particle clumping, or more generally, particle noise. The probable cause of shock waves is the Local Mixing Instability (LMI), previously identified in the literature. Particle noise on the other hand is a problem because it introduces a large error in the SPH momentum equation. We also investigate the role of artificial conductivity (AC). Including AC is necessary for the long-term behavior of the simulation (e.g. to get $\lambda=1/2, 1$ KH rolls). In sensitive hydrodynamical simulations great care is however needed in selecting the AC signal velocity, with the default formulation leading to too much energy diffusion. We present new signal velocities that lead to less diffusion. The effects of the shock waves and of particle disorder become less important as the time-scale of the physical problem (for the shearing layers problem: lower density contrast and higher Mach numbers) decreases. At the resolution of current galaxy formation simulations mixing is probably not important. However, mixing could become crucial for next-generation simulations.Comment: 16 pages, 23 figures, accepted for publication in MNRA

Analysis of the incompressibility constraint in the Smoothed Particle Hydrodynamics method

Smoothed particle hydrodynamics is a particle-based, fully Lagrangian, method for fluid-flow simulations. In this work, fundamental concepts of the method are first briefly recalled. Then, we present a thorough comparison of three different incompressibility treatments in SPH: the weakly compressible approach, where a suitably-chosen equation of state is used; and two truly incompressible methods, where the velocity field projection onto a divergence-free space is performed. A noteworthy aspect of the study is that, in each incompressibility treatment, the same boundary conditions are used (and further developed) which allows a direct comparison to be made. Problems associated with implementation are also discussed and an optimal choice of the computational parameters has been proposed and verified. Numerical results show that the present state-of-the-art truly incompressible method (based on a velocity correction) suffer from density accumulation errors. To address this issue, an algorithm, based on a correction for both particle velocities and positions, is presented. The usefulness of this density correction is examined and demonstrated in the last part of the paper

Early Postnatal Discharge for Infants: A Meta-analysis

CONTEXT: Postnatal length of hospital stay has reduced internationally but evidence-based abstract policies to support earlier discharge are lacking. OBJECTIVE: To determine the effects of early postnatal discharge on infant outcomes. DATA SOURCES: CENTRAL (Cochrane Central Register of Controlled Trials), Medline, Embase, Cumulative Index to Nursing and Allied Health Literature , and SCI (Science Citation Index) were searched through to January 15, 2018. STUDY SELECTION: Studies reporting infant outcomes with early postnatal discharge versus standard discharge were included if they met Effective Practice and Organisation of Care study design criteria. DATA EXTRACTION: Two authors independently assessed eligibility and extracted data, resolving disagreements by consensus. Data from interrupted time series (ITS) studies were extracted and reanalyzed in meta-analyses. Meta-analyses of randomized controlled trials (RCTs) used random effects models. RESULTS: Of 9298 studies, 15 met the inclusion criteria. RCT meta-analyses revealed that infants discharged ,48 hours after vaginal birth and ,96 hours after cesarean birth were more likely to be readmitted to the hospital within 28 days compared to standard discharge (risk ratio: 1.70; 95% confidence interval [CI] 1.34 to 2.15). ITS meta-analyses revealed a reduction in the proportion of infants readmitted within 28 days after minimum postnatal stay policies and legislation were introduced (change in slope: 20.62; 95% CI 21.83 to 0.60), with increasing impact in the first and second years (effect estimate: 24.27 [95% CI 27.91 to 20.63] and 26.23 [95% CI 210.15 to 22.32]). LIMITATIONS: Withdrawals and crossover limited the value of RCTs in this context but not ITS evidence. CONCLUSIONS: Infants discharged early after birth were more likely to be admitted within 28 days. The introduction of postnatal minimum length of stay policies was associated with a longterm reduction in neonatal hospital readmission rates

A SPH model for incompressible turbulence

A coarse-grained particle model for incompressible Navier-Stokes (NS) equation is proposed based on spatial filtering by utilizing smoothed particle hydrodynamics (SPH) approximations. This model is similar to our previous developed SPH discretization of NS equation ({\it Hu X.Y. & N.A. Adams, J. Comput. Physics}, 227: 264-278, 2007 and 228: 2082-2091, 2009) and the Lagrangian averaged NS (LANS-$\alpha$) turbulence model. Other than using smoothing approaches, this model obtains particle transport velocity by imposing constant $\sigma$ which is associated with the particle density, and is called SPH-$\sigma$ model. Numerical tests on two-dimensional decay and forced turbulences with high Reynolds number suggest that the model is able to reproduce both the inverse energy cascade and direct enstrophy cascade of the kinetic energy spectrum, the time scaling of enstrophy decay and the non-Guassian probability density function (PDF) of particle acceleration.Comment: 23 pages. 7 figure