Nobel Prize in Physics 2006

The discovery of the cosmic microwave background radiation in 1965 was a defining moment in the history of cosmology — the science that deals with the universe as a whole, its origin, evolution and future. This discovery was recognized with Nobel Prizes to Penzias and Wilson in 1978. The Nobel Prize in Physics for 2006 further acknowledged the importance of the study of this background radiation. The precise measurement of the spectrum of this radiation and its variation across the sky have helped our understanding of the evolution of structures in the universe. This article explains these discoveries and their importance. T Padmanabhan is a professor at IUCAA, Pune. He is interested in all aspects of theoretical physics, and especially in those in which gravity plays a role.     

文化的核心

在中国,英语专业的学生通常要学很多门"外国文化"课,学得最多的是英国和美国文化概况.如今,不管是谁,只要对此加以关注,就不应该仅仅认识到文化课所传递信息的重要,更应该能明确列举出开设这些课所要达到的目标.     

A Model of Rater Behavior in Essay Grading Based on Signal Detection Theory

An approach to essay grading based on signal detection theory (SDT) is presented. SDT offers a basis for understanding rater behavior with respect to the scoring of construct responses, in that it provides a theory of psychological processes underlying the raters' behavior. The approach also provides measures of the precision of the raters and the accuracy of classifications. An application of latent class SDT to essay grading is detailed, and similarities to and differences from item response theory (IRT) are noted. The validity and utility of classifications obtained from the SDT model and scores obtained from IRT models are compared. Validity coefficients were found to be about equal in magnitude across SDT and IRT models. Results from a simulation study of a 5-class SDT model with eight raters are also presented.     

Gender effects in children's beliefs about school performance: a cross-cultural study

Do young boys and girls understand what leads to academic success (e.g., talent, effort, good teaching, luck) in the same way? Do young girls and boys have equivalent perceptions of their academic competence? Are these beliefs engendered in the same way across sociocultural contexts? In a cross-cultural study of over 3,000 children in grades 2 to 6, ages 7.2 to 13.6, we discovered that boys and girls around the world have very similar ideas about what generally leads to academic success. Moreover, in the few contexts where boys' and girls' academic performances were equal, their beliefs were also equal. However, when girls outperformed boys, their beliefs in their own talent were no greater than boys' beliefs, even though they did have stronger beliefs than boys in other facets of their achievement potential (e.g., putting forth effort, being lucky, getting their teacher's help). Our findings support the generally close correspondence between children's achievement and their competence-related beliefs, with the exception that young girls appear to specifically discount their talent. The effects held regardless of the children's achievement, intelligence, or age (approximately 8 to 13 years). Girls were more biased in some contexts than in others, however, suggesting that competence-related biases are rooted in culture-specific aspects of school settings.     

Context-sensitive regularities in English vowel spelling

The predictive value of rime spellings in English was compared directly to other types of regularities beyond the level of the single letter. A computer-assisted analysis of a list of twenty-four thousand written words, each paired with its corresponding pronunciation, reveals that only a small number of rime spellings are highly regular in their pronunciations. The conventional division of vowel letter pronunciations into short and long in closed and open written syllables is the most reliable key to English pronunciation. Our findings support the notion that English spelling is based at least in part on syllable structure. In addition, prefixes and suffixes provide very reliable clues to pronunciation, which suggests that their regularity should be exploited in the teaching of reading.