Behavioral variability as a function of response topography and reinforcement contingency     

Laura Morgan  Allen Neuringer 《Learning & behavior》1990,18(3):257-263

Long-Evans rats were reinforced for generating variable sequences of responses on two operanda. The current sequence of four left and right responses was required to differ from each of the previous five sequences. Variability under thisvary schedule was compared with that under ayoke control schedule where reinforcement was independent of the sequences. Three different response topographies were compared: two levers were pressed in one case, two keys pushed in another, and two wires pulled in a third. Both reinforcement contingency (vary vs. yoke) and response topography (leverpress, key push, and wire pull) significantly influenced sequence variability. As is the case for operant dimensions, behavioral variability is jointly controlled by reinforcement contingency and response topography.  相似文献   

The effect of a role model project upon the attitudes of ninth-grade science students     

Mary Ann Evans  Myrna Whigham  Morgan C. Wang 《科学教学研究杂志》1995,32(2):195-204

This article will describe an in-school intervention project that used female role models to change the attitudes of 964 Iowa girls and boys in 57 ninth-grade science classes toward science, math, and technical curricula and careers. The differences between the students' mean pretest and posttest scores on each of six factors found to be associated with students' attitudes toward science and math and technical careers were analyzed to determine which of five experimental groups responded most positively to the intervention. Higher difference scores indicated that the attitudes of girls and boys who participated in the intervention improved more than the attitudes of girls and boys in the control groups, suggesting that the use of female role models in the science classroom is an effective way to change students' attitudes toward science, math, and related careers.  相似文献   

Are reading and behavior problems risk factors for each other?     

Morgan PL  Farkas G  Tufis PA  Sperling RA 《Journal of learning disabilities》2008,41(5):417-436

Two questions were investigated. First, are children with reading problems in first grade more likely to experience behavior problems in third grade? Second, are children with behavior problems in first grade more likely to experience reading problems in third grade? The authors explored both questions by using multilevel logistic regression modeling to analyze data from the Early Childhood Longitudinal Study-Kindergarten Class (ECLS-K). After statistically controlling for a wide range of potential confounds, they found that children with reading problems in first grade were significantly more likely to display poor task engagement, poor self-control, externalizing behavior problems, and internalizing behavior problems in third grade. They also found that children displaying poor task engagement in first grade were more likely to experience reading problems in third grade. Collectively, these findings suggest that the most effective types of interventions are likely to be those that target problems with reading and task-focused behaviors simultaneously.  相似文献   

Recess, physical education, and elementary school student outcomes     

Angela K. Dills  Hillary N. Morgan  Kurt W. Rotthoff 《Economics of Education Review》2011,30(5):889-900

Today's children experience a decreased amount of time at recess and fewer physical education (PE) classes throughout the school day. Breaks for physical activity limit class time for academics, potentially reducing learning. However, breaks may improve alertness and achievement. Using the Early Childhood Longitudinal Survey Kindergarten Class of 1998-1999, we evaluate how recess and PE in elementary school influence children's learning. We find no statistically significant or economically significant impacts of weekly recess or PE time on student learning for kindergarteners through fifth graders. For example, in kindergarten, adding an hour a week of recess reduces the average test score gain in reading by a statistically insignificant 0.01 standard deviations. An additional 49 min per week of PE in kindergarten improves reading test score gains by a statistically insignificant 0.05 standard deviations. We find no statistical difference in the male and female students’ response to recess and PE. Evidence suggests that recess and PE do not harm student outcomes.  相似文献   

Screening ion-channel ligand interactions with passive pumping in a microfluidic bilayer lipid membrane chip     

Shimul C. Saha  Andrew M. Powl  B. A. Wallace  Maurits R. R. de Planque  Hywel Morgan 《Biomicrofluidics》2015,9(1)

We describe a scalable artificial bilayer lipid membrane platform for rapid electrophysiological screening of ion channels and transporters. A passive pumping method is used to flow microliter volumes of ligand solution across a suspended bilayer within a microfluidic chip. Bilayers are stable at flow rates up to ∼0.5 μl/min. Phospholipid bilayers are formed across a photolithographically defined aperture made in a dry film resist within the microfluidic chip. Bilayers are stable for many days and the low shunt capacitance of the thin film support gives low-noise high-quality single ion channel recording. Dose-dependent transient blocking of α-hemolysin with β-cyclodextrin (β-CD) and polyethylene glycol is demonstrated and dose-dependent blocking studies of the KcsA potassium channel with tetraethylammonium show the potential for determining IC₅₀ values. The assays are fast (30 min for a complete IC₅₀ curve) and simple and require very small amounts of compounds (100 μg in 15 μl). The technology can be scaled so that multiple bilayers can be addressed, providing a screening platform for ion channels, transporters, and nanopores.  相似文献   

Improvements in fundamental movement skill competency mediate the effect of the SCORES intervention on physical activity and cardiorespiratory fitness in children     

Kristen E. Cohen  Philip J. Morgan  Ronald C. Plotnikoff  Lisa M. Barnett 《Journal of sports sciences》2015,33(18):1908-1918

Numerous studies have identified a positive association between fundamental movement skill (FMS) competency and physical activity in children; however, the causal pathways have not been established. The aim of this study is to determine if changes in FMS competency mediated the effect of the Supporting Children’s Outcomes using Rewards, Exercise and Skills (SCORES) intervention on physical activity and cardiorespiratory fitness in children. Eight primary schools (25 classes) and 460 children (aged 8.5 ± 0.6, 54% girls) were randomised to the SCORES intervention or control group for the 12-month study. The outcomes were accelerometer-determined moderate-to-vigorous physical activity (MVPA) and cardiorespiratory fitness. The hypothesised mediators were actual FMS competency and perceived sport competence. Mediation analyses were conducted using multilevel linear analysis in MPlus. From the original sample, 138 (30.0%) and 370 (80.4%) children provided useable physical activity and cardiorespiratory fitness data at post-test assessments. There were significant treatment effects for locomotor skills and overall FMSs. Changes in MVPA were associated with changes in object-control skills, overall FMSs and perceived competence. The overall FMSs had a significant mediating effect on MVPA (AB = 2.09, CI = 0.01–4.55). Overall FMSs (AB = 1.19, CI = 0.002–2.79) and locomotor skills (AB = 0.74, CI = 0.01–1.69) had a significant mediating effect on cardiorespiratory fitness. The results of this study conclude that actual but not perceived movement skill competency mediated the effect of the SCORES intervention on physical activity and cardiorespiratory fitness.  相似文献   

Characteristics impacting on session rating of perceived exertion training load in Australian footballers     

Tania Gallo  Stuart Cormack  Tim Gabbett  Morgan Williams  Christian Lorenzen 《Journal of sports sciences》2015,33(5):467-475

The relationship between external training load and session rating of perceived exertion (s-RPE) training load and the impact that playing experience, playing position and 2-km time-trial performance had on s-RPE training load were explored. From 39 Australian Football players, 6.9 ± 4.6 training sessions were analysed, resulting in 270 samples. Microtechnology devices provided external training load (distance, average speed, high-speed running distance, player load (PL) and player load_slow (PL_slow)). The external training load measures had moderate to very large associations (r, 95% CI) with s-RPE training load, average speed (0.45, 0.35–0.54), high-speed running distance (0.51, 0.42–0.59), PL_slow (0.80, 0.75–0.84), PL (0.86, 0.83–0.89) and distance (0.88, 0.85–0.90). Differences were described using effect sizes (d ±95% CL). When controlling for external training load, the 4- to 5-year players had higher s-RPE training load than the 0- to 1- (0.44 ± 0.33) and 2- to 3-year players (0.51 ± 0.30), ruckmen had moderately higher s-RPE training load than midfielders (0.82 ± 0.58), and there was a 0.2% increase in s-RPE training load per 1 s increase in time-trial (95% CI: 0.07–0.34). Experience, position and time-trial performance impacted the relationship between external training load and s-RPE training load. This suggests that a given external training load may result in different internal responses between athletes, potentially leaving individuals at risk of overtraining or failing to elicit positive adaptation. It is therefore vital that coaches and trainers give consideration to these mediators of s-RPE training load.  相似文献   

Racial Dynamics in the Teacher's Union     

Janet Morgan 《Equity & Excellence in Education》2013,46(4):67-70

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RESEARCH SECTION: The acceptability of psychosocial support interventions for children orphaned by HIV/AIDS: an evaluation of teacher ratings     

Morgan Chitiyo  Darlington Changara  George Chitiyo 《British Journal of Special Education》2010,37(2):95-101

The AIDS epidemic has created many orphans around the globe. A majority of these orphans live in sub‐Saharan Africa. Children orphaned by HIV/AIDS face many daunting challenges in their struggle to cope with life. The issues they face due to the loss of their parent(s) include poverty, the stigma associated with HIV/AIDS and stress. This study carried out by Morgan Chitiyo of Southern Illinois University Carbondale, Darlington Changara of Midlands AIDS Caring Organisation and George Chitiyo of Tennessee Technological University discusses how different psychosocial and educational interventions have been developed to help the children to overcome these challenges. However, few of the interventions have been empirically tested to determine their efficacy. The authors set out to evaluate the treatment acceptability of a psychosocial support programme using a group of teachers who had received training and were participating in the implementation of the programme across their schools. Findings from the study indicate high acceptability ratings of the programme.  相似文献   

Sport and Work.     

William J. Morgan 《体育哲学杂志》2013,40(1):78-83

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