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This study describes the effects of different weekly work intensity levels on adolescent functioning in a sample of 3,083 high school students in rural South Texas, where economically disadvantaged and Hispanic youth are heavily represented. Anonymous surveys were conducted in 10th- and 12th-grade students' classrooms in 1995. The following effects were associated with long hours of weekly employment during the school year: (1) decreased performance/engagement in school and satisfaction with amount of leisure time, and (2) increased health risk behaviors and psychological stress. The effects of school-year work on academic factors and health behaviors differed by grade, but not by race/ethnicity, parent education, or race/ethnicity and parent education considered together. It was concluded that parents and professionals should continue to monitor the number of weekly hours that students work during the school year.  相似文献   
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We investigated dorsal visual stream involvement in the retrieval of a variety of visual attributes of common objects, using functional magnetic resonance imaging. Seven subjects made binary decisions about the shape, color, and size of named objects during scanning. Bilateral parietal activity was significantly greater during retrieval of shape and size information than during retrieval of color information. Consistent with a domain-specific distributed model of semantic organization, the finding that dorsal stream activity is associated with size and shape retrieval, as compared with color retrieval, may indicate that both size and shape information are learned partly through dorsally mediated processes, such as visually guided grasping. These results demonstrate that both visual-processing streams (i.e., the ventral “what” pathway and the dorsal “where” pathway) are involved in the storage and/or retrieval of knowledge of object appearance but that, just as in vision, these two pathways may play different roles in conceptual processing.  相似文献   
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The effectiveness of a 5-s constant time-delay procedure to teach three chained food preparation behaviors to four moderately retarded adolescent students was evaluated within a multiple probe design across behaviors. Results indicate that the procedure was effective in teaching all four students to make a sandwich, boil a boil-in-bag item, and bake canned biscuits. The skills maintained with at least 85% accuracy over a 3-month period. Training generalized from the school to the home setting for the 2 subjects that completed generalization probe sessions. The percentage of errors across all skills and students was less than 9%.  相似文献   
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One solution to the difficulty of running real-time applications under UNIX is to develop the application programs on an available UNIX system and execute them on a dedicated satellite processor. This combines the advantages of a powerful timesharing operating system with the real-time capabilities of a single-process system. PARASITE, a real-time satellite system, provides tools for developing the application program on the host and executing it on a satellite. A host utility serves to invoke the standard UNIX C compiler and link its output with the PARASITE library. The PARASITE library consists of routines that mimic the standard library and routines that read and write the real-time peripherals. PARASITE currently supports digital inputs and outputs, asynchronous serial-line interfaces, program-mable real-time clocks, and analog-to-digital and digital-to-analog converters. Another PARA-SITE utility downloads the object code of the user program and PARASITE support code into the satellite, where it runs independently. Once the application routine is executing on the satellite, it controls the satellite processor at all times and is continuously available for servicing hardware-generated interrupts. When a real-time peripheral interrupt routine is invoked by a hardware interrupt, it sends a software signal to the user program, in addition to processing the interrupt. This allows the user program to perform additional tasks that are specific to the application. All data to be permanently stored must be transferred to the host. Since the satellite has no direct access to the resources of the host, a process running on the host receives the data and manages files. PARASITE provides packet driver routines on both the host and the satellite, which together handle the data transmission protocol.  相似文献   
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Teacher-rated adjustment differences among young elementary school children from (a) a recent sample and a 1974 cohort, and (b) urban/suburban, male/female, and grade-level subgroups were examined. A problem behavior checklist (Classroom Adjustment Rating Scale) and a school competence measure (Health Resources Inventory) for 974 children from 5 urban and 5 suburban schools were completed by 101 first- to fourth-grade teachers. Children from the more current cohort were rated as significantly more maladjusted than those from the earlier sample on 8 of 10 adjustment variables. In the recent sample, girls and suburban children evidenced a greater number of school competencies and fewer problem behaviors than boys and urban children, respectively. The implications of these findings for the future use of the teacher rating scales are discussed.  相似文献   
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The author discusses results from a 3 year quasi-experimental field study (N = 368), which suggest negative effects on employee outcomes after the implementation of 3 lean production practices: lean teams, assembly lines, and workflow formalization. Employees in all lean production groups were negatively affected, but those in assembly lines fared the worst, with reduced organizational commitment and role breadth self-efficacy and increased job depression. A nonequivalent control group had no negative changes in outcomes. Mediational analyses showed that the negative effects of lean production were at least partly attributable to declines in perceived work characteristics (job autonomy, skill utilization, and participation in decision making). The study also shows the longitudinal effects of these work characteristics on psychological outcomes. Implications for lean production, work design, and employee well-being are discussed.  相似文献   
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