Reliability-Based Design of Thermal Protection Systems with Support Vector Machines

The primary objective of this work was to develop a computationally efficient and accurate approach to reliability analysis of thermal protection systems using support vector machines. An adaptive sampling approach was introduced informs a iterative support vector machine approximation of the limit state function used for measuring reliability. The proposed sampling approach efficient adds samples along the limit state function until the reliability approximation is converged. This methodology is applied to two samples, mathematical functions to test and demonstrate the applicability. Then, the adaptive sampling-based support vector machine approach is applied to the reliability analysis of a thermal protection system. The results of all three problems highlight the potential capability of the new approach in terms of accuracy and computational saving in determining thermal protection system reliability

Calibration Probe Uncertainty and Validation for the Hypersonic Material Environmental Test System

This paper presents an uncertainty analysis of the stagnation-point calibration probe surface predictions for conditions that span the performance envelope of the Hypersonic Materials Environmental Test System facility located at NASA Langley Research Center. A second-order stochastic expansion was constructed over 47 uncertain parameters to evaluate the sensitivities, identify the most significant uncertain variables, and quantify the uncertainty in the stagnation-point heat flux and pressure predictions of the calibration probe for a low- and high-enthalpy test condition. A sensitivity analysis showed that measurement bias uncertainty is the most significant contributor to the stagnation-point pressure and heat flux variance for the low-enthalpy condition. For the high-enthalpy condition, a paradigm shift in sensitivities revealed the computational fluid dynamics model input uncertainty as the main contributor. A comparison between the prediction and measurement of the stagnation-point conditions under uncertainty showed that there was evidence of statistical disagreement. A validation metric was proposed and applied to the prediction uncertainty to account for the statistical disagreement when compared to the possible stagnation-point heat flux and pressure measurements

Biased sampling activity: an investigation to promote discussion.

The statistical concept of sampling is often given little direct attention, typically reduced to the mantra "take a random sample". This low resource and adaptable activity demonstrates sampling and explores issues that arise due to biased sampling

Modelling the dynamics of intramammary E. coli infections in dairy cows: understanding mechanisms that distinguish transient from persistent infections

The majority of intramammary infections with Escherichia coli in dairy cows result in transient infections with duration of about 10 days or less, although more persistent infections (2 months or longer) have been identified. We apply a mathematical model to explore the role of an intracellular mammary epithelial cell reservoir in the dynamics of infection. We included biological knowledge of the bovine immune response and known characteristics of the bacterial population in both transient and persistent infections. The results indicate that varying the survival duration of the intracellular reservoir reproduces the data for both transient and persistent infections. Survival in an intracellular reservoir is the most likely mechanism that ensures persistence of E. coli infections in mammary glands. Knowledge of the pathogenesis of persistent infections is essential to develop preventive and treatment programmes for these important infections in dairy cows

Mechanisms of Bacterial Extracellular Electron Exchange.

The biochemical mechanisms by which microbes interact with extracellular soluble metal ions and insoluble redox-active minerals have been the focus of intense research over the last three decades. The process presents two challenges to the microorganism; firstly electrons have to be transported at the cell surface, which in Gram negative bacteria presents an additional problem of electron transfer across the ~ 6 nm of the outer membrane. Secondly the electrons must be transferred to or from the terminal electron acceptors or donors. This review covers the known mechanisms that bacteria use to transport electrons across the cell envelope to external electron donors/acceptors. In Gram negative bacteria electron transfer across the outer membrane involves the use of an outer membrane β-barrel and cytochrome. These can be in the form of a porin-cytochrome protein, such as Cyc2 of Acidothiobacillus ferrioxydans, or a multiprotein porin-cytochrome complex like MtrCAB of Shewanella oneidensis MR-1. For mineral respiring organisms there is the additional challenge of transferring the electrons from the cell to mineral surface. For the strict anaerobe Geobacter sulfurreducens this requires electron transfer through conductive pili to associated cytochrome OmcS that directly reduces Fe(III)oxides, while the facultative anaerobe S. oneidensis MR-1 accomplishes mineral reduction through direct membrane contact, contact through filamentous extentions and soluble flavin shuttles, all of which require the outer membrane cytochromes MtrC and OmcA in addition to secreted flavin

Death Anxiety in a National Sample of United States Funeral Directors and its Relationship with Death Exposure, Age, and Sex

The purpose of this study is to examine the relationship between the level of death anxiety among a national sample of United States funeral directors with varying levels of death exposure, age, and sex. Utilizing the Multidimensional Fear of Death Scale (MFODS), the results showed a significant, but weak negative relationship between levels of death anxiety and the participants\u27 reported number of funerals attended per year. The correlation between death anxiety scores and the number of reported embalming cases performed yearly was, however, not significant. We found a significant negative correlation between death anxiety and age in both men and women funeral directors. The difference in the death anxiety scores between men (n = 166) and women (n = 38) funeral directors was not significant. There was a significant negative correlation with age in both men and women in several fears of death including fear of the dying process, fear for significant others, and fear of premature death. The significant negative correlations were stronger for women than men across all three subscales. Results, direction for further research, and implications of the findings for mental health workers are discussed

AGRO ECOSISTEMAS DE HUERTOS FAMILIARES EN EL SUBTRÓPICO DEL ALTIPLANO MEXICANO. UNA VISIÓN SISTÉMICA

Este trabajo está dirigido a evaluar el conocimiento tradicional aplicado en los agro ecosistemas con huertos familiares en la localidad de San Nicolás, ubicada al suroeste del Estado de México, en el sub trópico del Altiplano Central de México, generado por la Depresión del Río Balsas; la selección de los predios e informantes fue por intención. Se analizaron catorce sistemas entre marzo de 2011 y abril de 2012. Se elaboró la caracterización geográfica, fitogeográfica y agroecológica; la caracterización geográfica incluyó aspectos físicos, bióticos y socioculturales, empleando fotointerpretación, ubicación mediante sistemas de posicionamiento global, análisis de estadísticas sociales, observación directa de rasgos culturales y elaboración de cartografía digital. Para la caracterización fitogeográfica, se realizó un inventario florístico, que incluye desde el enfoque de la Etnobotánica el manejo y funcionalidad de los recursos vegetales utilizados en los agro ecosistemas de huertos familiares, basado en el conocimiento tradicional de los habitantes locales; se realizaron colectas de especímenes botánicos cultivados y silvestres. La caracterización agroecológica se elaboró mediante trabajo de campo y entrevistas realizadas a los dueños del predio, la información obtenida se procesó mediante bases de datos. El fundamento teórico de la investigación se sustentó en la Agroecología, la Ecología Cultural y la Etnobotánica. Estas permitieron evaluar la importancia ecológica, y determinar el impacto socioeconómico y cultural de los agro ecosistemas familiares bajo una visión sistémica

FLORA MEDICINAL EN SAN NICOLÁS, MUNICIPIO DE MALINALCO, ESTADO DE MÉXICO

Se determinaron aspectos sobre el hábitat, uso y función de los recursos vegetales utilizados en la medicina tradicional, en la comunidad de San Nicolás, municipio de Malinalco, ubicada al sur del Estado de México. De enero de 2010 a enero de 2011 se aplicaron entrevistas a 30 hombres y mujeres, de entre 20 y 60 años de edad. La observación directa y participativa permitió verificar la función y manejo de las plantas. Se registraron 165 especies correspondientes a 147 géneros y 70 familias de plantas vasculares. Las especies utilizadas en la medicina tradicional se agruparon en 13 clases o categorías de acuerdo con el tipo de enfermedad en que se utilizan. Las categorías de plantas medicinales que mostraron las mayores frecuencias de utilización se relacionan con el tratamiento de enfermedades del aparato digestivo, aparato respiratorio, enfermedades asociadas con la nutrición y sistema endócrino, además de las referidas como síndromes de filiación cultural. Las plantas medicinales se presentaron en dos diferentes hábitat; 45.4% son especies pertenecientes a la flora viaria y el 54.5% prosperan en agroecosistemas familiares, llamados localmente huertos o solares. Aproximadamente un tercio de las especies eran cultivadas y el resto silvestres. Tres cuartos de las especies presentan una distribución natural en América, y las demás han sido introducidas de ultramar. Los datos muestran que el mayor número de especies utilizadas para fines medicinales se encuentran en los huertos. Esto implica nuevos retos debido a que los huertos familiares tradicionales están siendo utilizados para fines diversos, como la construcción de viviendas o establecimientos comerciales, ocasionando pérdida de germoplasma insitu y en consecuencia pérdida de la biodiversidad en este territorio del subtrópico mexicano

Factors Affecting Implementation of an Evidence-Based Practice in the VA: Illness Management and Recovery

Objective: Illness management and recovery (IMR) is an evidence-based practice that assists consumers in managing their illnesses and pursuing personal recovery goals. Although research has examined factors affecting IMR implementation facilitated by multifaceted, active roll-outs, the current study attempted to elucidate factors affecting IMR implementation outside the context of a research-driven implementation. Methods: Semi-structured interviews with 20 local recovery coordinators and 18 local IMR experts were conducted at 23 VA medical centers. Interviews examined perceived and experienced barriers and facilitators to IMR implementation. Data were analyzed via thematic inductive/deductive analysis in the form of crystallization/immersion. Results: Six factors differed between sites implementing IMR from those not providing IMR: awareness of IMR, importer-champions, autonomy-supporting leadership, veteran-centered care, presence of a sensitive period, and presence of a psychosocial rehabilitation and recovery center. Four factors were common in both groups: recovery orientation, evidence-based practices orientation, perceived IMR fit within program structure, and availability of staff time. Conclusions and Implications for Practice: IMR can be adopted in lieu of active implementation support; however, knowledge dissemination appears to be key. Future research should examine factors affecting the quality of implementation. (PsycINFO Database Record (c) 2016 APA, all rights reserved