Research on fiber-reinforced composites

Research in materials science - high temperature structural materials, wetting and adherence of nickel alloys to sapphire, boron carbide filaments, and ceramic and graphite fiber

Effects of Genotype and Date of Harvest on Infection of Peanut Seed by Aspergillus flavus and Subsequent Contamination with Aflatoxin

Several peanut genotypes reported as resistant, susceptible or highly susceptible to in vitro colonization of rehydrated, mature, stored, undamaged seed by Aspergillus flavus (IVSCAF) were tested for natural seed infection by A. flavus and other fungi in two or more replicated field trials at ICRISAT Center, Patancheru, India, in 1979–1984. Undamaged pods were sampled before maturity, at optimum maturity (normal harvest) and when over - mature (late harvest) and seed examined for infection by A. flavus and other fungi. In the 1983 and 1984 rainy and 1983/84 postrainy seasons, only four genotypes (one resistant and three susceptible) were tested, and seed were also tested for aflatoxin content. In all seasons the genotypes reported as IVSCAF - resistant had significantly lower levels of seed infection with A. flavus and other fungi than did genotypes reported as IVSCAF - susceptible. Cenotypic differences in levels of seed infection by A. flavus were consistent over seasons. The resistant cultivar J11 had a significantly lower aflatoxin content than the other three IVSCAF - susceptible genotypes tested in the 1983–1984 seasons. Drought stress in the 1984 season apparently increased susceptibility to seed infection by A. flavus and other fungi, and to aflatoxin contamination, in all cultivars. Seed infection by A. flavus and other fungi, and aflatoxin contamination increased with increasing maturity of pods, indicating the importance of lifting the peanut crop at optimum maturity

A hashtag worth a thousand words: Discursive strategies around #JeNeSuisPasCharlie after the 2015 Charlie Hebdo shooting

Following a shooting attack by two self-proclaimed Islamist gunmen at the offices of French satirical weekly Charlie Hebdo on 7 January 2015, there emerged the hashtag #JeSuisCharlie on Twitter as an expression of solidarity and support for the magazine’s right to free speech. Almost simultaneously, however, there was also #JeNeSuisPasCharlie explicitly countering the former, affirmative hashtag. Based on a multimethod analysis of 74,047 tweets containing #JeNeSuisPasCharlie posted between 7 and 11 January, this article reveals that users of the hashtag under study employed various discursive strategies and tactics to challenge the mainstream framing of the shooting as the universal value of freedom of expression being threatened by religious extremism, while protecting themselves from the risk of being viewed as disrespecting victims or endorsing the violence committed. The significance of this study is twofold. First, it extends the literature on strategic speech acts by examining how such acts take place in a social media context. Second, it highlights the need for a multidimensional and reflective methodology when dealing with data mined from social media

Aflatoxin Contamination of Groundnut: Prospects for a Genetic Solution through Conventional Breeding

Af latoxin contamination of groundnut is a serious problem in most groundnut-producing countries. The aflatoxin-producing fungi, Aspergillus flavus and A. parasiticus, can invade groundnut seed in the field before harvest, during postharvest drying and curing, and in storage. The semi-arid tropical environment is conducive to preharvest contamination when the crop experiences drought before harvest, whereas in wet and humi d areas, postharvest contamination is more prevalent. Af latoxin contamination can be minimized by adopting some cultural, produce-handling, and storage practices. However, these practices have not been widely adopted by small farmers in developing countries which contribute about 60% of the world's groundnut product ion. Cultivars resistant to seed invasion by aflatoxin-producing fungi or to aflatoxin product ion woul d be of great value to farmers in both developed and developing countries. Therefore, breeding for resistance to aflatoxin-producing fungi and/or aflatoxin product ion can play a significant role in preventing aflatoxin contamination in groundnut , consequent economic losses, and health hazards. The alleviation of aflatoxin contamination through genetic manipulation has been at tempted since the mid 1970s. In spite of the significant progress achieved to date, these efforts have not resulted in complete freedom f rom aflatoxin contamination. The current status and future prospects of genetic solutions to the aflatoxin contamination problem are briefly discussed in this paper

Management of Drought Stress to Improve Field Screening of Peanuts for Resistance to Aspergillus flavus

Drought stress during late stages of pod maturation in an irrigated peanut crop during the postrainy season significantly increased the amount of seed infection by Aspergillus flavus. A line-source sprinkler irrigation system imposing a drought-stress gradient was used for field screening of peanut genotypes for resistance to seed infection by A. flavus. A significant, positive, linear relationship was found between water deficit (drought intensity) and seed infection in peanut genotypes. Genotypic differences for seed infection by A. flavus were evident at all levels of drought-stress, but, under the more severe drought stress conditions, the genotypes resistant to A. flavus had low but positive levels of seed infection giving improved statistical precision

Limited Lifespan of Fragile Regions in Mammalian Evolution

An important question in genome evolution is whether there exist fragile regions (rearrangement hotspots) where chromosomal rearrangements are happening over and over again. Although nearly all recent studies supported the existence of fragile regions in mammalian genomes, the most comprehensive phylogenomic study of mammals (Ma et al. (2006) Genome Research 16, 1557-1565) raised some doubts about their existence. We demonstrate that fragile regions are subject to a "birth and death" process, implying that fragility has limited evolutionary lifespan. This finding implies that fragile regions migrate to different locations in different mammals, explaining why there exist only a few chromosomal breakpoints shared between different lineages. The birth and death of fragile regions phenomenon reinforces the hypothesis that rearrangements are promoted by matching segmental duplications and suggests putative locations of the currently active fragile regions in the human genome

Investigating child participation in the everyday talk of a teacher and children in a preparatory year

In early years research, policy and education, a democratic perspective that positions children as participants and citizens is increasingly emphasized. These ideas take seriously listening to children’s opinions and respecting children’s influence over their everyday affairs. While much political and social investment has been paid to the inclusion of participatory approaches little has been reported on the practical achievement of such an approach in the day to day of early childhood education within school settings. This paper investigates talk and interaction in the everyday activities of a teacher and children in an Australian preparatory class (for children age 4-6 years) to see how ideas of child participation are experienced. We use an interactional analytic approach to demonstrate how participatory methods are employed in practical ways to manage routine interactions. Analysis shows that whilst the teacher seeks the children’s opinion and involves them in decision-making, child participation is at times constrained by the context and institutional categories of “teacher” and “student” that are jointly produced in their talk. The paper highlights tensions that arise for teachers as they balance a pedagogical intent of “teaching” and the associated institutional expectations, with efforts to engage children in decision-making. Recommendations include adopting a variety of conversational styles when engaging with children; consideration of temporal concerns and the need to acknowledge the culture of the school