Changes in children's self-competence and values: gender and domain differences across grades one through twelve

This study extended previous research on changes in children's self-beliefs by documenting domain-specific growth trajectories for 761 children across grades 1 through 12 in a longitudinal study of perceptions of self-competence and task values. Hierarchical Linear Modeling was used to (1) describe changes in beliefs across childhood and adolescence within the domains of mathematics, language arts, and sports; (2) examine the impact of changes in competence beliefs on changes in values over time in the same domains; and (3) describe gender differences in mean levels and trajectories of change in competence beliefs and values. The most striking finding across all domains was that self-perceptions of competence and subjective task values declined as children got older, although the extent and rate of decline varied across domains. For example, in language arts, competence beliefs declined rapidly during the elementary school years, but then leveled off or increased to some extent; whereas the decline in self-competence beliefs in sports accelerated during the high school years. Significant gender differences in beliefs were found in most domains; however, the gender differences in developmental trajectories appeared to be domain specific rather than global. Importantly, the gender differences between boys and girls did not systematically increase with age, as predicted by some socialization perspectives. Adding competence beliefs as an explanatory variable to the model for task values revealed that changes in competence beliefs accounted for much of the age-related decline in task values. In addition, competence beliefs accounted for most of the gender differences in task values for language arts and sports.     

Expression of a begomoviral DNAβ gene in transgenic Nicotiana plants induced abnormal cell division

An increasing number ofmonopartite begomoviruses are being identified that a satellite molecule (DNAβ) is required to induce typical symptoms in host plants. DNAβ encodes a single gene (termed βCl) encoded in the complementary-sense. We have produced transgenic Nieotiana benthamiana and N. tabaeum plants expressing the βC1 gene of a DNAβ associated with Tomato yellow leaf curl China virus (TYLCCNV), under the control of the Cauliflower mosaic virus 35S promoter. Transgenic plants expressing 13C1 showed severe developmental abnormalities in both species. Microscopic analysis of sections of both transgenic and non-transgenic N. tabaeum leaves showed abnormal outgrowths of transgenic N. tabaeum to be due to disorganizedcell division (hyperplasia) of spongy and palisade parenchyma. Immuno-gold labeling of sections with a polyclonal antibody against the βC1 protein showed that the 13C 1 protein accumulated in the nuclei of cells. The possible biological function of the βC1 1protein was discussed.     

Lunar outpost agriculture

America's long-term commitment to a new Space Exploration Initiative has focused attention on the basic requirements for establishing a permanently manned lunar outpost and, ultimately, a martian one. High among these is the development of Regenerative Life Support Systems--with lunar agriculture an essential component--to provide a high level of self-sufficiency.     

人物简介：基因医生

W．French Anderson开创了基因疗法