Unsteady Extinction of Opposed Jet Ethylene/Methane HIFiRE Surrogate Fuel Mixtures vs Air

A unique idealized study of the subject fuel vs. air systems was conducted using an Oscillatory-input Opposed Jet Burner (OOJB) system and a newly refined analysis. Extensive dynamic-extinction measurements were obtained on unanchored (free-floating) laminar Counter Flow Diffusion Flames (CFDFs) at 1-atm, stabilized by steady input velocities (e.g., U(sub air)) and perturbed by superimposed in-phase sinusoidal velocity inputs at fuel and air nozzle exits. Ethylene (C2H4) and methane (CH4), and intermediate 64/36 and 15/85 molar percent mixtures were studied. The latter gaseous surrogates were chosen earlier to mimic ignition and respective steady Flame Strengths (FS = U(sub air)) of vaporized and cracked, and un-cracked, JP-7 "like" kerosene for a Hypersonic International Flight Research Experimentation (HIFiRE) scramjet. For steady idealized flameholding, the 100% C2H4 flame is respectively approx. 1.3 and approx.2.7 times stronger than a 64/36 mix and CH4; but is still 12.0 times weaker than a 100% H2-air flame. Limited Hot-Wire (HW) measurements of velocity oscillations at convergent-nozzle exits, and more extensive Probe Microphone (PM) measurements of acoustic pressures, were used to normalize Dynamic FSs, which decayed linearly with pk/pk U(sub air) (velocity magnitude, HW), and also pk/pk P (pressure magnitude, PM). Thus Dynamic Flame Weakening (DFW) is defined as % decrease in FS per Pascal of pk/pk P oscillation, namely, DFW = -100 d(U(sub air)/U(sub air),0Hz)/d(pkpk P). Key findings are: (1) Ethylene flames are uniquely strong and resilient to extinction by oscillating inflows below 150 Hz; (2) Methane flames are uniquely weak; (3) Ethylene / methane surrogate flames are disproportionately strong with respect to ethylene content; and (4) Flame weakening is consistent with limited published results on forced unsteady CFDFs. Thus from 0 to approx. 10 Hz and slightly higher, lagging diffusive responses of key species led to progressive phase lags (relative to inputs) in the oscillating flames, and caused maximum weakening. At 20 to 150 Hz, diffusion-rate-limited effects diminished, causing flames to "regain strengnth," and eventually become completely insensitive beyond 300 Hz. Detailed mechanistic understanding is needed. Overall, ethylene flames are remarkably resilient to dynamic extinction by oscillating inflows. They are the strongest, with the notable exception of H2. For HIFiRE tests, the 64%/36% surrogate disproportionally retains the high dynamic FS of ethylene, so the potential for loss of scramjet flameholding (flameout) due to low frequency oscillations is significantly mitigated

De sangre y leche: Raza y religión en el mundo ibérico moderno

Sangre y leche fueron símbolos omnipresentes en los territorios de la «Monarquía Católica», en España y su Imperio colonial. Situados a medio camino entre la naturaleza y la cultura, a lo largo de las edades Media y Moderna, la sangre y la leche tejieron una poderosa analogía entre la reproducción fisiológica y la reproducción cultural. Como exploran los artículos de este libro, estos símbolos desempeñaron un papel determinante en los procesos de ordenación, jerarquización, y por supuesto también, de exclusión social dentro de la monarquía. Partiendo de perspectivas tan diversas como la religiosa, la social, la jurídica o la antropológica, los autores de este libro analizan esta privilegiada encrucijada simbólica para interrogarse sobre el origen y desarrollo del discurso de la «raza» en la España altomoderna.Índice: Introducción, por Mercedes García-Arenal y Felipe Pereda. SANGRE. LA POLÍTICA DEL LINAJE Y LA SANGRE. -Genealogía, linaje e identidad etnocultural en la Granada nazarí, por Mohamad Ballan. -Religión y raza en la Edad Media cristiana e islámica, por David Nirenberg. -Linaje, conversión y naturalezas inestables en el Atlántico ibérico: comparación entre la incorporación y la exclusión de los moriscos y de los pueblos indígenas, por Karoline P. Cook. -Limpieza de sangre: la batalla por la reforma desde Salucio hasta Quevedo, por Francisco Bethencourt. LA SANGRE, VEHÍCULO DE LA NATURALEZA INMUTABLE. -Sangre de mi sangre: lo que no se podía adquirir, o casi no, por Jean-Frédéric Schaub. -Demonios, estrellas e imaginación. El cuerpo a principios de la modernidad en los trópicos, por Jorge Cañizares-Esguerra. -«Sua malicia vem-se a conaturizar»: Sangre, color de piel y conversión en el mundo ibérico moderno, por Giuseppe Marcocci. -Los «judíos menstruantes». Sangre, bautismo y la retórica de la evidencia en un tratado de Juan de Quiñones (1632), por Stefania Pastore. SANGRE & LECHE. EL DISCURSO SIMBÓLICO DE LOS FLUIDOS SACROS .-Líquidos sagrados y la formación de protestantes (españoles), por James S. Amelang. -Divinos pechos, como cántaros: estética, política y género de las imágenes del Barroco español, por Felipe Pereda. -La puesta en escena de la limpieza de sangre en la España del siglo XVII, por Rachel Burk. REPRESENTACIONES Y FICCIONES. -Saberes médicos e ideología esencialista: sangre, esperma, leche y construcción del ser, por Christine Orobitg. -Ficciones genealógicas. El morisco Román Ramírez y los libros de caballerías, por Miguel Martínez. -Del morisco real al imaginado. Construcciones de la alteridad en la Península Ibérica moderna, por Francisco J. Moreno Díaz del Campo y Borja Franco Llopis. A MODO DE COLOFÓN. -De sangre y leche: debates y categorías sobre racialización. Una lectura retrospectiva, por Max S. Hering Torres. -¿Eran racistas los europeos de la modernidad temprana?, por Joan Pau Rubiès.Peer reviewe

Introduction to special issue:New Times Revisited: Britain in the 1980s

The authors in this volume are collectively engaged with a historical puzzle: What happens if we examine the decade once we step out of the shadows cast by Thatcher? That is, does the decade of the 1980s as a significant and meaningful periodisation (equivalent to that of the 1960s) still work if Thatcher becomes but one part of the story rather than the story itself? The essays in this collection suggest that the 1980s only makes sense as a political period. They situate the 1980s within various longer term trajectories that show the events of the decade to be as much the consequence as the cause of bigger, long-term historical processes. This introduction contextualises the collection within the wider literature, before explaining the collective and individual contributions made

Effects of Selenium Supplementation on Selenoprotein Gene Expression and Response to Influenza Vaccine Challenge: A Randomised Controlled Trial

Background: The uncertainty surrounding dietary requirements for selenium (Se) is partly due to limitations in biomarkers of Se status that are related to health outcomes. In this study we determined the effect of different doses and forms of Se on gene expression of selenoprotein S (SEPS1), selenoprotein W (SEPW1) and selenoprotein R (SEPR), and responses to an immune function challenge, influenza vaccine, were measured in order to identify functional markers of Se status. Methods and Findings: A 12 week human dietary intervention study was undertaken in 119 volunteers who received placebo, 50, 100 or 200 µg/day Se-enriched yeast (Se-yeast) or meals containing unenriched or Se-enriched onions (50 µg/day). Gene expression was quantified in RNA samples extracted from human peripheral blood mononuclear cells (PBMC's) using quantitative RT-PCR. There was a significant increase in SEPW1 mRNA in the Se-enriched onion group (50 µg/day) compared with the unenriched onion group. SEPR and SEPW1 did not change significantly over the duration of the supplementation period in the control or Se-yeast groups, except at week 10 when SEPW1 mRNA levels were significantly lower in the 200 µg/day Se-yeast group compared to the placebo group. Levels of SEPS1 mRNA increased significantly 7 days after the influenza vaccine challenge, the magnitude of the increase in SEPS1 gene expression was dose-dependent, with a significantly greater response with higher Se supplementation. Conclusions: This novel finding provides preliminary evidence for a role of SEPS1 in the immune response, and further supports the relationship between Se status and immune function

Somatic mosaicism and common genetic variation contribute to the risk of very-early-onset inflammatory bowel disease

Very-early-onset inflammatory bowel disease (VEO-IBD) is a heterogeneous phenotype associated with a spectrum of rare Mendelian disorders. Here, we perform whole-exome-sequencing and genome-wide genotyping in 145 patients (median age-at-diagnosis of 3.5 years), in whom no Mendelian disorders were clinically suspected. In five patients we detect a primary immunodeficiency or enteropathy, with clinical consequences (XIAP, CYBA, SH2D1A, PCSK1). We also present a case study of a VEO-IBD patient with a mosaic de novo, pathogenic allele in CYBB. The mutation is present in ~70% of phagocytes and sufficient to result in defective bacterial handling but not life-threatening infections. Finally, we show that VEO-IBD patients have, on average, higher IBD polygenic risk scores than population controls (99 patients and 18,780 controls; P < 4 × 10-10), and replicate this finding in an independent cohort of VEO-IBD cases and controls (117 patients and 2,603 controls; P < 5 × 10-10). This discovery indicates that a polygenic component operates in VEO-IBD pathogenesis