The relationship among stress, support, depression, and academic performance for rural adolescents

The constructs of stress, support, depression, and academic performance have been mostly addressed on an individual basis. Stress research with children and adolescents has not been as rigorous as research with adults. There are also a number of gaps in the research literature related to support. The decrease in age of the first onset of depressive episodes, along with the high prevalence of depression in adolescence, emphasizes the need to expand research in this area. Also, few studies have attempted to identify interpersonal variables that may serve as antecedents of school achievement. The purpose of this study was to examine the relationships among stress, support, depression, and academic performance. A sample of senior high school students from two school districts in a rural county in northwest Ohio was the participants. Data was obtained from 218 students, who were surveyed using an instrument designed specifically for the study. The relationships between the variables in this model were tested by a statistical methodology called structural equation modeling (SEM). The five observed variables considered to measure Depression were all considered moderate to very good measures, with the items within the Depressed Affect subscale serving as the most valid measure. The results indicated Academic Efficacy was a much better measure of Academic Performance versus Grades. Family served as the most valid measure of Support. Although weak, there was a significant positive relationship between Stress and Depression. There was a significant negative relationship between Depression and Academic Performance. There was also a significant negative relationship between Depression and Support. The relationship between Depression and Support was stronger than the relationship between Depression and Academic Performance. The relationship between Support and Academic Performance was the weakest of all correlations and was not statistically significant. Thus, it appeared that Support may not have been working as a substantive buffer against Stress. One disconcerting finding within this study was the high percentage (40%) of students citing significant depressive symptomatology, indicating a greater risk for major depressive disorder. The overarching goal of the study was to increase awareness for the need for mental health services in the schools

Gene discovery for improvement of kernel quality-related traits in maize

Developing maize plants with improved kernel quality traits involves the ability to use existing genetic variation and to identify and manipulate commercially important genes. This will open avenues for designing novel variation in grain composition and will provide the basis for the development of the next generation of specialty maize. This paper provides an overview of current knowledge on the identification and exploitation of genes affecting the composition, development, and structure of the maize kernel with particular emphasis on pathways relevant to endosperm growth and development, differentiation of starch-filled cells, and biosynthesis of starches, storage proteins, lipids, and carotenoids. The potential that the new technologies of cell and molecular biology will provide for the creation of new variation in the future are also indicated and discussed

Osmolyte-related recovery of the opaque-6 lethal phenotype in Zea mays L

Endosperm growth and development is a complex phenomenon, driven by the coordinate expression of several genes. A series of endosperm mutants with altered timing and zein synthesis rate have been studied, allowing the partial unravelling of a multifarious system, integrating carbohydrate, amino acid, and storage protein me¬tabolisms, and operating during endosperm growth and development. The exact biological function of one of these loci, the Opaque-6 (O6) gene, remains to be acknowledged. The o6 locus determines a general reduction of 19- and 22 kDa zeins as well as a number of non-zein polypeptides present in the wild type endosperm. The o6 mutants present a collapsed, dull endosperm, leaf striations and early seedling death; however, o6 seedlings can survive when grown in the presence of exogenous proline. It has been suggested that, in mutant seeds and in con¬trast with the development of the normal seeds, proline does not reach the sites of protein synthesis in adequate amounts. Yet, it has been demonstrated that amino acids other than proline are also able to restore o6 seedling le¬thality, contradicting this hypothesis. In this paper, we explored the possibility that the observed proline-mediated rescue of o6 mutant seedling lethality regarded an osmolyte-mediated mitigation of aberrant protein folding rather than the restoration of a reduced proline flux needed for protein synthesis. This hypothesis was tested by means of in vitro cultivation of o6 seedlings in the presence of putative osmolytes including a series of amino acids, me¬thylamines, and polyols. Several osmolytes were identified, which were able to restore normal growth in o6 mutant seedlings. Root reestablishment required higher osmolyte concentrations than those necessary for the recovery of the aboveground plant parts. The results presented in this paper provide sufficient preliminary evidence to assume that proline-induced recovery of the o6 mutant phenotype depends on the osmolytic properties of this amino acid

Asymmetric Optical Radiation Pressure Effects on Liquid Interfaces Under Intense Illumination

Deformations of horizontal liquid interfaces by optical radiation pressure are generally expected to display similar behaviors whatever the direction of propagation of the exciting laser beam is. In the present experiment we find this expectation to be borne out, as long as the cw laser illumination is moderate in strength. However, as a striking contrast in the case of high field strengths, we find that either a large stable tether can be formed, or else that a break-up of the interface can occur, depending on whether the laser beam is upward or downward directed. Physically, the reason for this asymmetry can be traced to whether total reflection can occur or not. We also present two simple theoretical models, one based on geometrical optics, the other on wave optics, that are able to illustrate the essence of the effect. In the case leading to interface disruption our experimental results are compared with those obtained by Zhang and Chang for water droplets under intense laser pulses [Opt. Lett. \textbf{13}, 916 (1988)]. A key point in our experimental investigations is to work with a near-critical liquid/liquid interface. The surface tension becomes therefore significantly reduced, which thus enhances the magnitude of the stationary deformations induced.Comment: 25 pages text, plus 6 figures. Discussion expanded. Submitted to JOSA

The academic papers researchers regard as significant are not those that are highly cited

For many years, academia has relied on citation count as the main way to measure the impact or importance of research, informing metrics such as the Impact Factor and the h-index. But how well do these metrics actually align with researchers' subjective evaluation of impact and significance? Rachel Borchardt and Matthew R. Hartings report on a study that compares researchers' perceptions of significance, importance, and what is highly cited with actual citation data. The results reveal a strikingly large discrepancy between perceptions of impact and the metric we currently use to measure it

Quality related traits of the maize (Zea mays L) grain: gene identification and exploitation

Developing maize plants with improved kernel quality traits involves the ability to use existing genetic variation and to identify and manipulate commercially important genes. This will open opportunities for designing novel variation in grain composition and will provide the basis for the development of the next generation of specialty maize. This paper provides an overview of current knowledge on the identification and exploitation of genes affecting the composition, development, and structure of the maize kernel with particular emphasis on pathways relevant to endosperm growth and development, differentiation of starch-filled cells, and biosynthesis of starches, storage proteins, lipids, and carotenoids. The potential that the new technologies of cell and molecular biology will provide for the creation of new variation in the future are also indicated and discussed

Electron tunneling through sensitizer wires bound to proteins

We report a quantitative theoretical analysis of long-range electron transfer through sensitizer wires bound in the active-site channel of cytochrome P450cam. Each sensitizer wire consists of a substrate group with high binding affinity for the enzyme active site connected to a ruthenium-diimine through a bridging aliphatic or aromatic chain. Experiments have revealed a dramatic dependence of electron transfer rates on the chemical composition of both the bridging group and the substrate. Using combined molecular dynamics simulations and electronic coupling calculations, we show that electron tunneling through perfluorinated aromatic bridges is promoted by enhanced superexchange coupling through virtual reduced states. In contrast, electron flow through aliphatic bridges occurs by hole-mediated superexchange. We have found that a small number of wire conformations with strong donor–acceptor couplings can account for the observed electron tunneling rates for sensitizer wires terminated with either ethylbenzene or adamantane. In these instances, the rate is dependent not only on electronic coupling of the donor and acceptor but also on the nuclear motion of the sensitizer wire, necessitating the calculation of average rates over the course of a molecular dynamics simulation. These calculations along with related recent findings have made it possible to analyze the results of many other sensitizer-wire experiments that in turn point to new directions in our attempts to observe reactive intermediates in the catalytic cycles of P450 and other heme enzymes

The continuum of spreading depolarizations in acute cortical lesion development: Examining Leao's legacy.

A modern understanding of how cerebral cortical lesions develop after acute brain injury is based on Aristides Leao's historic discoveries of spreading depression and asphyxial/anoxic depolarization. Treated as separate entities for decades, we now appreciate that these events define a continuum of spreading mass depolarizations, a concept that is central to understanding their pathologic effects. Within minutes of acute severe ischemia, the onset of persistent depolarization triggers the breakdown of ion homeostasis and development of cytotoxic edema. These persistent changes are diagnosed as diffusion restriction in magnetic resonance imaging and define the ischemic core. In delayed lesion growth, transient spreading depolarizations arise spontaneously in the ischemic penumbra and induce further persistent depolarization and excitotoxic damage, progressively expanding the ischemic core. The causal role of these waves in lesion development has been proven by real-time monitoring of electrophysiology, blood flow, and cytotoxic edema. The spreading depolarization continuum further applies to other models of acute cortical lesions, suggesting that it is a universal principle of cortical lesion development. These pathophysiologic concepts establish a working hypothesis for translation to human disease, where complex patterns of depolarizations are observed in acute brain injury and appear to mediate and signal ongoing secondary damage