On the mechanisms governing gas penetration into a tokamak plasma during a massive gas injection

A new 1D radial fluid code, IMAGINE, is used to simulate the penetration of gas into a tokamak plasma during a massive gas injection (MGI). The main result is that the gas is in general strongly braked as it reaches the plasma, due to mechanisms related to charge exchange and (to a smaller extent) recombination. As a result, only a fraction of the gas penetrates into the plasma. Also, a shock wave is created in the gas which propagates away from the plasma, braking and compressing the incoming gas. Simulation results are quantitatively consistent, at least in terms of orders of magnitude, with experimental data for a D 2 MGI into a JET Ohmic plasma. Simulations of MGI into the background plasma surrounding a runaway electron beam show that if the background electron density is too high, the gas may not penetrate, suggesting a possible explanation for the recent results of Reux et al in JET (2015 Nucl. Fusion 55 093013)

IL-6 is a predictive biomarker for stroke associated infection and future mortality in the elderly after an ischemic stroke

Background and purposeStroke associated infection (within the first seven days) occurs in approximately half of stroke patients and is associated with a worse prognosis, especially in the elderly. It is uncertain what factors predict stroke associated infection, yet identification of a suitable biomarker for infection may allow early and appropriate intervention with antibiotics. The aims of this study were to: a) identify independent risk factors for stroke associated infection, and b) test relationships between these risk factors and mortality at 2 years.MethodsEight-two elderly patients were assessed within 72 h of stroke. Data on stroke severity (Barthel Index), stroke associated infection and mortality at 2 years were collected. Inflammatory biomarkers at baseline and 6 months were measured by ELISA. Logistic regression was used to identify risk factors for stroke associated infection and death.ResultsPatients with stroke associated infection, especially pneumonia, had increased IL-6, more severe strokes, and higher mortality. IL-6 was independently associated with stroke associated infection (OR = 19.2, [95%CI 3.68, 100], p < 0.001), after adjustment for other risk factors and cytokines. IL-6 was also independently associated with 2 year mortality (OR = 9.2, [1.0, 85.1], p = 0.031).ConclusionsThese data suggest that IL-6 may be a key biomarker for predicting stroke associated infection and mortality in the first two years post stroke

Modeling the relationship between prosodic sensitivity and early literacy

A growing literature has demonstrated that prosodic sensitivity is related to early literacy development; however, the precise nature of this relationship remains unclear. It has been speculated in recent theoretical models that the observed relationship between prosodic sensitivity and early literacy might be partially mediated by children's vocabulary knowledge, phonological awareness, and morphological awareness, although such models have yet to be confirmed using advanced statistical techniques. The study reported here uses covariance structure modeling to provide the first direct test of the model proposed by Wood, Wade-Woolley, and Holliman. We also test a modified version of this model that was designed to overcome some of the limitations in the original. Seventy-five 5–7-year-old English-speaking children completed a new measure of prosodic sensitivity and were also assessed for their vocabulary knowledge, phonological awareness, morphological awareness, word reading, and spelling. The results showed that Wood et al.'s model did not provide an adequate fit to our sample data; however, the new model, which permitted causal connections between the so-called mediator variables, provided an excellent fit. We argue that prosodic sensitivity should be afforded greater importance in models of literacy development, and offer a new theoretical model of the prosody–literacy relationship for future attempts at replication