Plasma Spraying of Kaolinite for Preparing Reactive Alumino-Silicate Glass Coatings

Thermally treated kaolinite is used to develop a range of alumino-silicate-based precursor materials but its behavior during plasma spraying has not been well-researched. In this study, two types of kaolinite samples were investigated in the form of low defect (KGa-1b) and high defect (KGa-2) varieties. The extreme temperatures of the plasma stream (up to 20 000 K) induced flash melting to produce a highly porous alumino-silicate glass without any crystallization of new Al−Si oxide minerals. The glass is comprised largely of intact or deformed spheres (average diameters 1.14–1.44 μm), which indicates rapid quenching and solidification before impact. The subspherical structures contain up to 40 % closed pore space caused by the rapid escape of water during melting. The low-density, porous alumino-silicate glass coatings with predicted specific surface areas (>0.95 m2/g) and hardnesses >1.8 GPa represent a potentially reactive but physically stable substrate ideal for further chemical functionalization

Expert opinion as an instrument for assessing investment in primary education

Includes bibliographyMost educational investment is based on untested or partially tested assumptions about the cost-effectiveness of a given course of action. Indeed, the only estimates that have been available have been for the average profitability of each type of education, even though these differ greatly from marginal profitability. This article sets out a new approach to estimating the cost-effectiveness of educational investment. The authors canvassed the views of ten world-renowned educational researchers on the likely impact on students' learning achievements of a set of forty measures generally regarded as desirable for improving primary education, and supplemented the responses received with their own calculations of the cost of each, the aim being to establish an index of cost-effectiveness. On this basis, they concluded that the educational projects implemented in the region have failed to include many of the measures identified as the most efficient, and this has limited the quality of the education provided and its potential contribution to economic success, despite the considerable increase in educational investment by governments and international bodies in the 1990s. The article concludes with a number of recommendations aimed at remedying this situation, which take account simultaneously of the impact and the cost of the different educational measures

Las evaluaciones educativas que América Latina necesita

Los autores de este documento son los miembros del Comité Gestor del Grupo de Trabajo sobre Estándares y Evaluación del PREAL.Este documento aborda la importancia, propósitos y usos de las evaluaciones estandarizadas a gran escala de aprendizajes y logros escolares que se vienen realizando en América Latina y el Caribe, entendiendo por evaluación estandarizada a gran escala a aquélla que permite producir información comparable acerca de los desempeños de estudiantes pertenecientes a distintos contextos culturales y regionales e, incluso, a distintos países, y que ofrece un panorama de la situación de un país o de un estado o provincia, aplicando pruebas y otros instrumentos a muestras o a censos de estudiantes. El texto puede ayudar a quienes toman decisiones de política educativa a comprender y analizar diversas opciones existentes en cuanto a los propósitos y usos de los sistemas de evaluación y las implicancias de cada una de ellas, evitando simplismos que puedan generar sistemas mal concebidos y deficientemente implementados y, como consecuencia de ello, efectos perversos para el sistema educativo, malgasto de recursos y descrédito de la evaluación externa entre los docentes. Argumentan los autores que, para que la inversión en evaluación valga la pena, debe tener propósitos claros, una filosofía orientada a construir una visión de responsabilidad compartida en relación a la educación, un diseño técnico de calidad y adecuado a los propósitos, una fuerte orientación a servir de apoyo a los docentes y una clara voluntad política de actuar para resolver los problemas y deficiencias que la evaluación ponga de manifiesto. Asimismo, se requiere invertir tiempo y recursos en construir una unidad técnica competente y un plan de largo plazo

Folic acid to reduce neonatal mortality from neural tube disorders

Background Neural tube defects (NTDs) remain an important, preventable cause of mortality and morbidity. High-income countries have reported large reductions in NTDs associated with folic acid supplementation or fortification. The burden of NTDs in low-income countries and the effectiveness of folic acid fortification/supplementation are unclear

The combined immunodetection of AP-2α and YY1 transcription factors is associated with ERBB2 gene overexpression in primary breast tumors

INTRODUCTION: Overexpression of the ERBB2 oncogene is observed in about 20% of human breast tumors and is the consequence of increased transcription rates frequently associated with gene amplification. Several studies have shown a link between activator protein 2 (AP-2) transcription factors and ERBB2 gene expression in breast cancer cell lines. Moreover, the Yin Yang 1 (YY1) transcription factor has been shown to stimulate AP-2 transcriptional activity on the ERBB2 promoter in vitro. In this report, we examined the relationships between ERBB2, AP-2alpha, and YY1 both in breast cancer tissue specimens and in a mammary cancer cell line. METHODS: ERBB2, AP-2alpha, and YY1 protein levels were analyzed by immunohistochemistry in a panel of 55 primary breast tumors. ERBB2 gene amplification status was determined by fluorescent in situ hybridization. Correlations were evaluated by a chi2 test at a p value of less than 0.05. The functional role of AP-2alpha and YY1 on ERBB2 gene expression was analyzed by small interfering RNA (siRNA) transfection in the BT-474 mammary cancer cell line followed by real-time reverse transcription-polymerase chain reaction and Western blotting. RESULTS: We observed a statistically significant correlation between ERBB2 and AP-2alpha levels in the tumors (p < 0.01). Moreover, associations were found between ERBB2 protein level and the combined high expression of AP-2alpha and YY1 (p < 0.02) as well as between the expression of AP-2alpha and YY1 (p < 0.001). Furthermore, the levels of both AP-2alpha and YY1 proteins were inversely correlated to ERBB2 gene amplification status in the tumors (p < 0.01). Transfection of siRNAs targeting AP-2alpha and AP-2gamma mRNAs in the BT-474 breast cancer cell line repressed the expression of the endogenous ERBB2 gene at both the mRNA and protein levels. Moreover, the additional transfection of an siRNA directed against the YY1 transcript further reduced the ERBB2 protein level, suggesting that AP-2 and YY1 transcription factors cooperate to stimulate the transcription of the ERBB2 gene. CONCLUSION: This study highlights the role of both AP-2alpha and YY1 transcription factors in ERBB2 oncogene overexpression in breast tumors. Our results also suggest that high ERBB2 expression may result either from gene amplification or from increased transcription factor levels

Effect of Pictorial Depth Cues, Binocular Disparity Cues and Motion Parallax Depth Cues on Lightness Perception in Three-Dimensional Virtual Scenes

Surface lightness perception is affected by scene interpretation. There is some experimental evidence that perceived lightness under bi-ocular viewing conditions is different from perceived lightness in actual scenes but there are also reports that viewing conditions have little or no effect on perceived color. We investigated how mixes of depth cues affect perception of lightness in three-dimensional rendered scenes containing strong gradients of illumination in depth.Observers viewed a virtual room (4 m width x 5 m height x 17.5 m depth) with checkerboard walls and floor. In four conditions, the room was presented with or without binocular disparity (BD) depth cues and with or without motion parallax (MP) depth cues. In all conditions, observers were asked to adjust the luminance of a comparison surface to match the lightness of test surfaces placed at seven different depths (8.5-17.5 m) in the scene. We estimated lightness versus depth profiles in all four depth cue conditions. Even when observers had only pictorial depth cues (no MP, no BD), they partially but significantly discounted the illumination gradient in judging lightness. Adding either MP or BD led to significantly greater discounting and both cues together produced the greatest discounting. The effects of MP and BD were approximately additive. BD had greater influence at near distances than far.These results suggest the surface lightness perception is modulated by three-dimensional perception/interpretation using pictorial, binocular-disparity, and motion-parallax cues additively. We propose a two-stage (2D and 3D) processing model for lightness perception

Tracking the international spread of SARS-CoV-2 lineages B.1.1.7 and B.1.351/501Y-V2

Publisher Copyright: © 2021 O'Toole Á et al.Late in 2020, two genetically-distinct clusters of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) with mutations of biological concern were reported, one in the United Kingdom and one in South Africa. Using a combination of data from routine surveillance, genomic sequencing and international travel we track the international dispersal of lineages B.1.1.7 and B.1.351 (variant 501Y-V2). We account for potential biases in genomic surveillance efforts by including passenger volumes from location of where the lineage was first reported, London and South Africa respectively. Using the software tool grinch (global report investigating novel coronavirus haplotypes), we track the international spread of lineages of concern with automated daily reports, Further, we have built a custom tracking website (cov-lineages.org/global_report.html) which hosts this daily report and will continue to include novel SARS-CoV-2 lineages of concern as they are detected.Peer reviewe