Solid-phase microextraction for flavor analysis in Harari Khat (<Emphasis Type="Italic">Catha edulis</Emphasis>) stimulant

This research examined the typical flavor compounds in the commonest type of Khat called Harari Khat grown in the region of Ethiopia. Twenty-eight compounds, which includes 1,2-Propanedione, 1-Phenyl, Hexanol, Hexanal compounds, Limonene, Benzaldehyde with other flavors, were extracted by polydimethylsiloxane at room temperature for 30 min from Khat samples, and identified by solid-phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS). This method needs no organic solvents and required minimal sample. Project supported by scholarship from China     

Stable individual differences on developmental tasks in young yellow-crowned parakeets,<Emphasis Type="Italic">Cyanoramphus auriceps</Emphasis>

We report on stable individual differences in young yellow-crowned parakeets across 38 tasks of cognitive development on three scales involving object permanence, means-end relations, and spatial relations. Stable performance ranks on blocks of tasks emerged after 13 weeks in two groups of sibling parakeets, one hand-reared and the other parent-reared. Examination of subject characteristics, such as hatch order, sex, general activity level, avoidances, latencies, social status, and errors, showed no significant correlations with these performance ranks. Characteristic individual approaches to unstructured play activities (from a fourth scale) were consistent with individual behavioral differences seen on the structured cognitive tasks.     

综合理科课程理解的几个误区

通过详实的资料 ,对综合理科课程的涵义、产生和发展、课程类型、教学目标、教学评价特征以及与分科理科课程和理科综合考试的关系进行了全面论证 ,从而澄清了当前对于综合理科认识的几个误区     

Enhancing Elementary Science Teachers’ Knowledge of Teaching: The Case of Designing and Implementing an Instructional Unit

This article provides a model for the professional development of elementary science teachers. The model focused on integrating different domains of knowledge into science teaching, including the knowledge of the science curriculum, especially scientific inquiry, teachers knowledge, and students knowledge. The two case studies in this article revealed that the teachers construct their knowledge in a social context. The constant reflections on the experiences helped them to generate alternative teaching approaches. The findings suggest that the model of the project had two functions. First, it provides a useful strategy to help science teachers to bridge the gap between theories of teaching and their own teaching practices. Second, it provides a social learning environment for learning how to teach science.     

Characterization of cellulose acetate micropore membrane immobilized acylase I

This paper describes an innovative method for the immobilization of acylase I, which was entrapped into the CA-CTA micropore membrane. The most suitable casting solutions proportion for immobilizing the enzyme was ob tained through orthogonal experiment. Properties of the enzyme membrane were investigated and compared with those of free enzyme and blank membrane. The thermal stability and pH stability of the enzyme inside the membrane were changed by immobilization. The optimum pH was found to be 6.0, which changes 1.0 unit compared with that of free acylase I. The optimum temperature was found to be about 90 ℃C, which is higher than that of free acylase I (60 ℃). Experimental results showed that immobilization had effects on the kinetic parameters of acylase I.     

A Conceptual Framework for Assessing Motivation and Self-Regulated Learning in College Students

A conceptual framework for assessing student motivation and self-regulated learning in the college classroom is presented. The framework is based on a self-regulatory (SRL) perspective on student motivation and learning in contrast to a student approaches to learning (SAL) perspective. The differences between SRL and SAL approaches are discussed, as are the implications of the SRL conceptual framework for developing instruments to assess college student motivation and learning. The conceptual framework may be useful in guiding future research on college student motivation and learning.     

Seizing the Opportunity to Create Uncertainty in Learning Mathematics

The paper is a reflective account of the design and implementation of mathematical tasks that evoke uncertainty for the learner. Three types of uncertainty associated with mathematical tasks are discussed and illustrated: competing claims, unknown path or questionable conclusion, and non-readily verifiable outcomes. One task is presented in depth, pointing to the dynamic nature of task design, and the added value stimulated by the uncertainty component entailed in the task in terms of mathematical and pedagogical musing.     

Linking Assessment and Intervention for Developmental/Functional Outcomes of Premature,Low-birth-weight Children

Prematurity and low birth weight (LBW) are two major biological factors that put infants and young children at high risk for developmental delays or disabilities. While survival rates for premature and LBW children have improved, incidence figures have changed little over the past 20 years; in fact, the incidence of LBW has increased. Although the vast majority of LBW children have normal outcomes, as a group, they have higher risk for subnormal growth, illnesses, and neurodevelopmental problems. The purpose of this article is to examine the factors that influence the effectiveness of early intervention for premature, LBW children and to describe a strategy for linking assessment and early intervention. Linking assessment and intervention involves comprehensive assessment; a team approach to both assessment and intervention; empowering and enabling families; and the development of functional goals and objectives.     

Secondary Education Systemic Issues: Addressing Possible Contributors to a Leak in the Science Education Pipeline and Potential Solutions

To maintain the legacy of cutting edge scientific innovation in the United States our country must address the many pressing issues facing science education today. One of the most important issues relating to science education is the under-representation of African Americans and Hispanics in the science, technology, and engineering workforce. Foreshadowing such under-representation in the workforce are the disproportionately low rates of African American and Hispanic students attaining college degrees in science and related fields. Evidence suggests disparate systemic factors in secondary science education are contributing to disproportionately low numbers of African American and Hispanic students in the science education pipeline. The present paper embarks on a critical analysis of the issue by elucidating some of the systemic factors within secondary education that contribute to the leak in the science education pipeline. In addition, this review offers a synthesis and explication of some of the policies and programs being implemented to address disparate systemic factors in secondary schools. Finally, recommendations are offered regarding potential mechanisms by which disparities may be alleviated.     

The Relationship Between School Composition,School Process and Mathematics Achievement in Secondary Education in Argentina

Using data from the 1998 High School National Census from the Ministry of Education and Culture of Argentina, the present study examines relationships between school composition, some characteristics of schooling (such as institutional culture and climate), and students’ achievement in Mathematics in the last year of high school. The study applies multilevel linear modeling on the levels of student, school and state. It finds a close relationship between achievement in Mathematics and the variables of school composition and schooling processes. It shows that when both variables act together, the effect of all other variables significantly decreases. The variables of schooling processes, however, even when diminished in influence, nonetheless notably continue to affect students’ achievements. The study also identifes a reference model for future studies evaluating other institutional factors of learning.