Political status, industrial structure, and migration : assessing the prospects of changes in the Puerto Rican economy (1982-2000)

Thesis (M.C.P.)--Massachusetts Institute of Technology, Dept. of Urban Studies and Planning, 1992.Includes bibliographical references (leaves 126-128).by Irma L. Pérez-Johnson.M.C.P

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Parsing Hispanic-White achievement gaps: The influence of individual, family, and school factors on Mathematics achievement differences in the elementary grades

Persistent academic achievement gaps have been noted among children of different race-ethnic and socioeconomic backgrounds in the United States. The patterns and causes of these gaps are not well understood, especially for Hispanic students. With Hispanics accounting for an increasing share of students and workers in our nation, expanding our understanding of Hispanic-White achievement differences takes on increased importance. This dissertation applies hierarchical growth curve modeling techniques to the analysis of data from the Early Childhood Longitudinal Study-Kindergarten Cohort (ECLS-K). It examines the associations between individual characteristics and characteristics of children\u27s home and school environments, and the Mathematics learning trajectories for Hispanic and White children from Kindergarten to the fifth grade. The ECLS-K is an ideal dataset to study these issues. Its nationally representative sample, multiple information sources, and longitudinal design make it possible to model children\u27s learning trajectories, identify factors across diverse domains that help account for differences in learning, and assess their relative importance. Hence, study data can help identify promising policy levers to reduce or eliminate Hispanic-White achievement differences. The study makes several important contributions. It helps address the important gap in the literature on Hispanic-White achievement differences. It examines the most appropriate longitudinal measures of achievement and applies the most appropriate statistical techniques to their analysis. The study also examines the effects of within-child changes in factors associated with Mathematics achievement, and investigates possible heterogeneity in such effects. Key findings include wide disparities in Mathematics achievement between Hispanic and White students, both within and between schools, and especially at Kindergarten entry. These differences are strongly related to Hispanic-White background differences that predict lower achievement for any child —for example, persistent poverty, limited preschool participation, and fewer educational resources at home. An important risk factor for Hispanic children is coming from a non-English-speaking household. Children\u27s trajectories of Mathematics learning after school entry are fairly similar and decreasing over time. Evidence of heterogeneity in achievement effects was limited. Study findings suggest the importance of early intervention and a need for expanded compensatory policies and new intervention strategies for the elementary grades

Parsing Hispanic-White achievement gaps: The influence of individual, family, and school factors on Mathematics achievement differences in the elementary grades

Persistent academic achievement gaps have been noted among children of different race-ethnic and socioeconomic backgrounds in the United States. The patterns and causes of these gaps are not well understood, especially for Hispanic students. With Hispanics accounting for an increasing share of students and workers in our nation, expanding our understanding of Hispanic-White achievement differences takes on increased importance. This dissertation applies hierarchical growth curve modeling techniques to the analysis of data from the Early Childhood Longitudinal Study-Kindergarten Cohort (ECLS-K). It examines the associations between individual characteristics and characteristics of children\u27s home and school environments, and the Mathematics learning trajectories for Hispanic and White children from Kindergarten to the fifth grade. The ECLS-K is an ideal dataset to study these issues. Its nationally representative sample, multiple information sources, and longitudinal design make it possible to model children\u27s learning trajectories, identify factors across diverse domains that help account for differences in learning, and assess their relative importance. Hence, study data can help identify promising policy levers to reduce or eliminate Hispanic-White achievement differences. The study makes several important contributions. It helps address the important gap in the literature on Hispanic-White achievement differences. It examines the most appropriate longitudinal measures of achievement and applies the most appropriate statistical techniques to their analysis. The study also examines the effects of within-child changes in factors associated with Mathematics achievement, and investigates possible heterogeneity in such effects. Key findings include wide disparities in Mathematics achievement between Hispanic and White students, both within and between schools, and especially at Kindergarten entry. These differences are strongly related to Hispanic-White background differences that predict lower achievement for any child —for example, persistent poverty, limited preschool participation, and fewer educational resources at home. An important risk factor for Hispanic children is coming from a non-English-speaking household. Children\u27s trajectories of Mathematics learning after school entry are fairly similar and decreasing over time. Evidence of heterogeneity in achievement effects was limited. Study findings suggest the importance of early intervention and a need for expanded compensatory policies and new intervention strategies for the elementary grades