Sorting Second-Grade Students: Differentiating Those Retained From Those Promoted.

A cohort of 2nd-grade students provided comparisons of academic and social competence based on school retention/promotion decisions. Sample groups were (a) retained, (b) at risk for retention, (c) special education, and (d) promoted. Findings suggested most children with academic deficiencies are identified by schools early and are sorted into educational treatments differing in intensity that represent a continuum of competence. The authors provide empirical evidence counter to the assumptions that retained students have the requisite ability to catch up and have more problem behaviors than other low-achieving students. The relevance of high-stakes test scores for promotion/retention decisions and the parallels between schools' implementation of retention policy and implementation of regulations for identifying children with disabilities are included in the discussion. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

硬质合金长条薄片弯曲变形的控制

从毛坯厚度差、装舟方式、冷却速度、舟皿涂料等方面分析了YG8和J12硬质合金长条薄片的弯曲变形原因,提出了几种抑制弯曲变形的措施。     

Effect of temperature and retention period on biogas production from lignocellulosic material

The extensive utilization of biogas for energy needs of rural dwellers would reduce their dependence on fossil fuels and fuelwoods and henoe camplement Government afforestation programes. In this investigation, effect of temperature and retention period on biogas production from lignooellulosic material, hereafter referred to as cow dung were studied. Maximum gas production was dotained at thermophilic temperature. The results of the effect of retention period shows that gas production was qotimum at 4th and 7th weeks of production.     

Optimal size,hydraulic retention time and volatile solids loading rate of biogas unit using water hyacinth

With a view to evaluate the effects of hydraulic retention time and volatile solids loading rate on methane production using water hyacinth, experiments were conducted in a 160 dm³ capacity, well-mixed continuous digestion unit at ambient temperature. The optimal design of biogas plant using water hyacinth was elucidated, to provide a unit giving a maximum methane yield of 0.16 nm³ kg^?1 volatile solids added, which was 60% greater than the conventional plant using cowdung. The calculations of optimal design factors were based on reactor size, hydraulic retention time and volatile solids loading rate; considerations were made of capital cost, running costs and operational revenue.     

Persistence of conditioned flavor preferences is not due to inadvertent food reinforcement.

Almond preferences were produced by giving rats a mixture of almond and sucrose (Experiments 1-4) or saccharin (Experiment 4). A subsequent extinction procedure consisted of either repeated 2-bottle almond versus water tests (Experiment 1) or repeated exposure to almond alone (Experiments 2-4). The main independent variable was whether access to food following a session was given immediately, 30 min later, or 120 min later. No effect of extinction was found in any experiment. An important finding was that varying the delay until food access had no detectable effect. It was concluded that inadvertent flavor-food associations do not maintain preference for the flavor under extinction conditions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Alliance and Dropout in Family Therapy for Adolescents With Behavior Problems: Individual and Systemic Effects.

This study examined the relationship between alliance and retention in family therapy. Alliance was examined at the individual (parent and adolescent) and family levels (within-family differences). Participants were 34 families who received functional family therapy for the treatment of adolescent (aged 12-18 years) behavior problems. Families were classified as treatment dropouts (n=14) or completers (n=20). Videotapes of the first sessions were rated to identify parent and adolescent alliances with the therapist. Results demonstrated that individual parent and adolescent alliances did not predict retention. However, as hypothesized, dropout cases had significantly higher unbalanced alliances (parent minus adolescent) than did completer cases. These findings highlight the importance of alliances in functional family therapy and suggest that how the alliance operates in conjoint family therapy may be a function of systemic rather than of individual processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Influence of Storage Time and Temperature on Absorption of Flavor Compounds from Solutions by Plastic Packaging Materials

ABSTRACT: Linear low-density polyethylene (LLDPE), oriented polypropylene (OPP), polycarbonate (PC), polyethylene terephthalate (PET film and PET bottle), and polyethylene naphthalate (PEN) were stored in a model solution containing 10 flavor compounds at 4, 20, and 40 °C and flavor absorption by the plastic materials was followed in time. The absorption rate and/or total amount absorbed increased considerably with temperature from 4 to 40 °C. Depending on storage temperature, total flavor absorption by the polyolefins (LLDPE and OPP) was 3 to 2400 times higher than by the polyesters (PC, PET, and PEN). Therefore, in the factor of flavor absorption, polyesters are preferred over polyolefins as packaging material.