Pathogenesis of porcine reproductive and respiratory syndrome virus-induced maternal reproductive failure

Porcine reproductive and respiratory syndrome (PRRS) is a disease of swine that was first recognized in the late 1980\u27s as epizootics of maternal reproductive failure and severe respiratory disease in young pigs. The etiology, the PRRS virus (PRRSV), was discovered in 1991 and is classified as a new member of the virus family Arteriviridae. Maternal reproductive failure attributed to PRRSV is characterized by increases in late-gestation abortions, early farrowings, weak pigs, stillborn pigs, and late and regular returns to estrus. Following natural exposure, it appears gilts and sows may develop a protective immune response to PRRSV;This dissertation compiles studies beginning in 1992 that investigated the pathogenesis of PRRSV-induced maternal reproductive failure utilizing an experimental model that involved exposure of gilts and sows to PRRSV at various stages of gestation. Results indicated that PRRSV may have little detrimental effect on conception or embryonic development. However, as gestation progresses the incidence of transplacental infection increases and the fetus becomes more susceptible to the lethal effects of an intrauterine PRRSV infection. Homologous protective immunity was demonstrated that developed within 90 days after exposure to PRRSV and persisted for at least 600 days. In contrast, heterologous protective immunity may have limited cross-protection and duration, this may be due to antigenic relatedness of the challenge and vaccine virus. The cause of reproductive failure may be attributed to a virus-induced vasculitis that involves maternal and fetal tissues. The severity of vascular lesions is variable among fetuses within a litter and among gilts within the same treatment group. This may account for the diverse range of clinical signs attributed to PRRSV in the field. Additional studies demonstrated passively acquired immunity conferred limited protection to piglets, however, it did not prevent piglets from being infected and transmitting virus to contact controls. PRRSV is a primary swine pathogen that is capable of causing severe reproductive losses. Fortunately, a protective immune response can be induced with vaccine that may aid in the prevention and control of PRRS

Barycentric coordinates

Thesis (M.A.)--Boston University, 1940A number triple defines, algebraically, a point in a plane; a number quadruple a point in space. The physical interpretation of these number groups vary, giving rise to the various systems of homogeneous coordinates. The particular case in which we are interested is that in which these numbers are interpreted as masses. It is at once evident that with an extended interpretation to the term "mass," we may define any point in space as the center of mass of four masses at four fixed points. It is further evident that the mutual ratio of these masses is sufficient to label this point . The configuration of four fixed points at which the masses are located is referred to as the base tetrahedron, and the four masses or more specifically, the ratios of these masses are called the barycentric coordinates of this point. The point itself is referred to as the barycenter of the four masses

Leptomeningeal Metastases in High-Grade Adult Glioma: Development, Diagnosis, Management, and Outcomes in a Series of 34 Patients

Leptomeningeal metastases (LM) in the setting of glioma have often been thought to carry a particularly poor prognosis. We sought to better characterize this phenomenon through a review of patients with glioma seen in our institution over the preceding 10 years. We focus here on 34 cases with LM due to grade III or IV glioma. Over the period in question we estimate a prevalence of almost 4% in those affected by grade IV tumors. Leptomeningeal spread was present at the time of initial diagnosis in 4 patients. In the others, LM occurred at the time of first progression of disease in 17. The median time to development of LM (excluding those where it was present at initial diagnosis) was 16.4 months (95% confidence interval (CI) 8.2-43.9). The median time to further progression of disease following LM was 4.9 months (95% CI 3.1- 6.9). 25 patients were known to have died at the time of writing. Thus median overall survival (OS) was 10.2 months (95% CI 8.8-14.7) following LM. At the time of diagnosis of LM, some form of treatment (chemotherapy and/or radiation vs. no treatment) increased OS (median 11.7 vs. 3.3 months, p\u3c0.001 by log-rank test). Use of radiation therapy (vs. no radiation) also increased OS, although the effect was more modest (7.8 vs. 16.8 months, p=0.07). Higher Karnofsky Performance Status (KPS) at the time of diagnosis of LM was associated with OS (p=0.007, median OS for KPS ‰¥90 19 months vs. 7.8 for KPS \u3c90). In a two-variable model incorporating the use any treatment (vs. none) and KPS, KPS tended to be a more significant predictor of survival (p=0.22 vs. p=0.06 by likelihood-ratio test). This was also true for radiation (vs. none) and KPS (p=0.27 vs. p=0.02). No significant benefit could be demonstrated for the use of chemotherapy considered alone, either systemic or intrathecal. It should be noted that 4 of 9 patients receiving intrathecal chemotherapy had a ventriculoperitoneal shunt in place during these injections, which may have reduced its effectiveness

Significados de Justicia: Una reflexión a partir de un estudio con personas en situación de desplazamiento forzado por la violencia política

Sociedad & Economía #20. Año 2011Desplazamiento Forzado, Violencia Política, Justicia, Significados

The effect of age on relational encoding as revealed by hippocampal functional connectivity

The neural processes mediating cognition occur in networks distributed throughout the brain. The encoding and retrieval of relational memories, memories for multiple items or multifeatural events, is supported by a network of brain regions, particularly the hippocampus. The hippocampal coupling hypothesis suggests that the hippocampus is functionally connected with the default mode network (DMN) during retrieval, but during encoding, decouples from the DMN. Based on prior research suggesting that older adults are less able to modulate between brain network states, we tested the hypothesis that older adults’ hippocampus would show functional connectivity with the DMN during relational encoding. The results suggest that, while the hippocampus is functionally connected to some regions of the DMN during relational encoding in both younger and older adults, older adults show additional DMN connectivity. Such age-related changes in network modulation appear not to be mediated by compensatory processes, but rather to reflect a form of neural inefficiency, most likely due to reduced inhibition

“WALK30X5”:A feasibility study of a physiotherapy walking programme for people with mild to moderate musculoskeletal conditions

Objectives: To explore the feasibility of delivering and evaluating a web-based walking intervention for people with long term musculoskeletal conditions (LTMCs), to determine its acceptability and the feasibility of conducting a definitive trial.  Design: Prospective randomised feasibility study, with blind outcome assessment at baseline, 3 and 6 months. Setting: Hospital based physiotherapy service. Participants: Forty one adults referred for assessment and advice for any mild/moderate LTMCs. doing <120 minutes of moderate intensity activity per week.  Interventions: Participants randomised to: 1. Usual care: one usual physiotherapy advice and assessment session, including setting a physical activity goal and one follow up session (8 weeks). 2. “Walk30 × 5”: session one, usual care plus intervention of walking programme. Participants were shown the website and podcasts and practiced how to use them. One follow up session (8 weeks). Outcome measures: Primary: timed six minute walk test (T6MWT). Secondary: step count, self-reported pain, fatigue, mood, self-efficacy, happiness, objective blood pressure, peak expiratory flow rate, and self-report and accelerometer measured physical activity.  Results: Recruitment target achieved. No adverse events occurred. Adherence was high and the intervention acceptable. Loss to follow up n = 3 (7%) at 3 months, n = 8 (20%) at 6 months. T6MWT and step count proved suitable outcomes, unlike accelerometry. Estimated sample size for a definitive trial is 216.  Conclusions: “Walk30 × 5” is ready for evaluation in a future, appropriately powered (n = 216), phase III trial. If effective, the intervention will provide a cheap, highly accessible intervention to enable people with mild/moderate LTMCs to achieve UK physical activity guidelines.  Clinical Trial Registration Number: ISRCTN78581097

The Effect of Income on Educational Attainment: Evidence from State Earned Income Tax Credit Expansions

As of the early 2000s, the gap in college enrollment between children growing up in the highest income quartile and the lowest income quartile was over 50 percentage points (Bailey and Dynarski 2011). While previous work has analyzed the impact of various federal and state financial aid programs on college enrollment rates among low and moderate-income households, the Earned Income Tax Credit (EITC) has largely been overlooked as a potential source of financial aid. As of the 2011 tax year, the maximum federal EITC benefit was nearly $6,000, worth up to 45$1,000, 18-23 year old children growing up in likely EITC-eligible households are 1 percentage point more likely to have ever enrolled in college and 0.3 percentage points more likely to complete a bachelor’s degree

Life Cycle Analysis of a SpaceCube Printed Circuit Board Assembly Using Physics of Failure Methodologies

In this reliability life cycle evaluation of the SpaceCube 2.0 processor card, a partially populated version of the card is being evaluated to determine its durability with respect to typical GSFC mission loads