407 research outputs found

    Gold standard or fool's gold: the pursuit of certainty in experimental criminology

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    This article assesses some of the claims made for experimental research in the field of rehabilitation of offenders. It suggests that both policy officials and evaluators have tended to over-invest financially and intellectually in a technocratic model of reducing reoffending that emphasizes programmes for offenders, and to under-invest in models that see the process as a complex ‘people changing’ skill. It argues that the complexity of this process renders it hard to evaluate using experimental methods of evaluation such as randomized controlled trials (RCTs). RCTs provide strong internal validity, but in complex settings offer weak external validity, making it hard to generalize from the experimental setting to other settings. The article suggests that the proper role for evaluative research in this field should be seen as building and testing middle-level theories about how best to change offenders’ behaviour

    Sediment resuspension rates, organic matter quality and food utilization by sea scallops (Placopecten magellanicus) on Georges Bank

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    Benthic detritus, bacteria, and settled phytoplankton are transported into the water column by resuspension, potentially providing a high quality food source to suspension feeders. Two aspects of resuspension must be considered in relation to food supplies for suspension feeders: the flux of particles from the sediments to the water column and its food value. Sediment resuspension rates on Georges Bank and the role of resuspended sediment in the diet of sea scallops (Placopecten magellanicus) were determined in laboratory flume experiments and shipboard feeding experiments, respectively. Resuspended carbon flux was estimated from flume bedload transport rates and the mass of organic carbon associated with the silt-clay fraction eroded from Georges Bank sediment during transport. A comparison of sand erosion thresholds with the frequency distribution of shear velocity estimated from field current meters indicated that tidal sediment resuspension will occur 62% of the time. Resuspended material had a carbon content of 4–8% and a C:N of 5–8. Rates of resuspension (33–229 mg C m−2h−1) and settling rates indicate that resuspended sediment in a size range available to scallops (\u3e5 μm) remains in suspension for periods of hours to days. Clearance rates of resuspended sediment by scallops were similar to those for water column particles, and filtration rates increased with increasing concentrations of resuspended material. Feeding experiments demonstrated that scallops absorbed organic matter from resuspended sediments with an efficiency of up to 40%. Therefore, in terms of particle retention, ingestion, and digestion, sea scallops are able to exploit resuspended organic matter from a continental shelf habitat. Furthermore, resuspension occurs with sufficient frequency, and resuspended sediment has long enough residence time in the water column to provide a consistent nutritional benefit to scallops

    A novel putter design to minimise range variability in golf putts

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    Putting accounts for more shots in a round of golf than any other type of play. The percentage of putts holed decreases as putt length increases, because golfers struggle to achieve a consistent range and direction. Range variation has been partly attributed to the ball striking the club face away from the central plane of the putter face. Tests have shown a 30mm off-centre impact can reduce the roll distance of a putt by 13%. In this paper, changes in mass distribution of the putter body and the addition of a flexible striking surface are considered. Physical testing and Finite Element Analysis are used to produce a club design with more consistent roll distance. Redistribution of mass reduced the roll distance variation across the clubface. Combining this with a flexible impact surface reduced the variation between a central impact and one 20mm from centre to just 1%. The proposed design could significantly reduce distance variation; aiding golfers in holing putts. Future work will optimise the design and validate through physical prototyping

    Modeling and testing compulsive eating behavior in animals

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    The study of compulsive eating has been swiftly gaining attention in both preclinical and clinical research. Compulsive eating behaviors characterize obesity and several eating disorders and can be conceptualized as being composed of three main elements: 1. habitual overeating, 2. overeating to alleviate a negative emotional state, and 3. overeating despite negative consequences. At a preclinical level, developing appropriate and clinically-relevant animal models and tests has been a barrier to investigating the neurobiological substrates of compulsive eating with the purpose of refining pharmacological interventions for forms of obesity and eating disorders. Throughout this review, we will describe the strategies used to develop animal models, first detailing experimental manipulations that are most commonly used to facilitate development of compulsive eating behavior and then we will focus on the tests used to measure compulsive eating as defined by the three aforementioned elements. Retuning the methodological approach towards compulsive eating behavior is essential to understand the complex mechanisms underlying the maladaptive food intake in forms of obesity and eating disorders.2020-07-03T00:00:00

    Minimizing the risk qualification test wafers have on the manufacturing readings of a new microprocessor fabrication site through data processes

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    Thesis (S.M.)--Massachusetts Institute of Technology, Sloan School of Management; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2001.Includes bibliographical references (p. 73).by Jonathan E. Howe.S.M

    Motor imagery during action observation enhances automatic imitation in children with and without developmental coordination disorder

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    Developmental coordination disorder (DCD) is a neurodevelopmental condition characterized by uncoordinated movement relative to age. While action observation (AO) and motor imagery (MI) can both independently enhance movement skills in children, we report the first study to assess the effects of combined action observation and motor imagery (AO + MI) on automatic imitation in children aged 7–12 years both with DCD (n = 12) and without DCD (n = 12). On each trial, participants planned to execute an instructed rhythmical action (face washing or paint brushing). Before responding, participants observed a rhythmical distractor showing the same or a different action with a subtle speed manipulation across trials (fast vs. slow). Automatic imitation was quantified as an imitation bias in subsequent response cycle times. Across blocks of trials, participants engaged in AO, MI, or combined AO + MI during the distractor phase or intentionally imitated the distractor speeds. Although there were no between groups differences, combined AO + MI instructions produced a significantly greater imitation bias (115%) than both AO (109%) and MI (109%), with intentional imitation yielding the strongest effects overall (128%). Within groups analyses revealed a significant bias for AO and MI in both groups. Combined AO + MI effects were significantly greater than AO in typically developing children and were greater than both AO and MI in children with DCD. These results demonstrate a clear capacity for different forms of motor simulation in children both with and without DCD. Moreover, combined AO + MI instructions represent an advantageous method for training movements in children with different motor abilities compared with separate AO and MI instructions.</p

    Combined action observation and motor imagery therapy: a novel method for post-stroke motor rehabilitation

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    Cerebral vascular accidents (strokes) are a leading cause of motor deficiency in millions of people worldwide. While a complex range of biological systems is affected following a stroke, in this paper we focus primarily on impairments of the motor system and the recovery of motor skills. We briefly review research that has assessed two types of mental practice, which are currently recommended in stroke rehabilitation. Namely, action observation (AO) therapy and motor imagery (MI) training. We highlight the strengths and limitations in both techniques, before making the case for combined action observation and motor imagery (AO + MI) therapy as a potentially more effective method. This is based on a growing body of multimodal brain imaging research showing advantages for combined AO + MI instructions over the two separate methods of AO and MI. Finally, we offer a series of suggestions and considerations for how combined AO + MI therapy could be employed in neurorehabilitation

    The application of the drug user quality of life scale (DUQOL) in Australia

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    <p>Abstract</p> <p>Background</p> <p>The concept of quality of life relates to the perceptions of individuals about their mental and physical health as well as non-health related areas. The evaluation of quality of life in the context of substance abuse has been conducted using generic instruments. The Drug Users Quality of Life Scale (DUQOL) is a specific assessment tool in which the most pertinent and salient areas to drug abusers are taken into consideration. In this study, the authors report the results of a validation study in which the DUQOL was used for the first time in Australia.</p> <p>Methods</p> <p>A sample of 120 participants from inpatient and outpatient treatment facilities completed a series of questionnaires, including the DUQOL and the World Health Organization Quality of Life Assessment-BREF (WHOQOL-BREF). Parameters investigated in this study included the demographic characteristics of the sample, internal structure, and convergent validity. Correlations between the DUQOL scale scores and the scores of the WHOQOL-Bref test were investigated via Pearson product-moment correlation analyses.</p> <p>Results</p> <p>The English version of the DUQOL attained a significant overall Cronbach's alpha of 0.868. The factorial analysis of the DUQOL identified one principal factor that accounted for 28.499% of the variance. Convergent validity analyses demonstrate significant correlations (<it>p </it>< 0.01) between the DUQOL scores and the scores of all four dimensions of the WHOQOL-BREF questionnaire.</p> <p>Conclusions</p> <p>This study demonstrates that the DUQOL constitutes a reliable research instrument for evaluating quality of life of substance users in Australia.</p

    The Obesity Paradox and Cardiorespiratory Fitness

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    Cardiorespiratory fitness as an explanation for the obesity paradox warrants further examination. We evaluated independent and joint associations of cardiorespiratory fitness and adiposity with all-cause mortality in 811 middle-aged (age, 53.3 ± 7.2 years) male never smokers without documented cardiopulmonary disease or diabetes from the Veterans Exercise Testing Study (VETS). Cardiorespiratory fitness was quantified in metabolic equivalents (METs) using final treadmill speed and grade achieved on a maximal exercise test. Subjects were grouped for analysis by METs: unfit (lowest third) and fit (upper two-thirds); and by body mass index (kg/m2): nonobese (18.5−29.9) and obese (≥30.0). Associations of baseline fitness and adiposity measures with all-cause mortality were determined by Cox proportional hazards analysis adjusted for age, ethnicity, hypertension, hypercholesterolemia, family history of coronary artery disease, and cardiovascular medication use. In multivariate analysis, mortality risk for obese/fit men did not differ significantly from the nonobese/fit reference group. However, compared to the reference group, nonobese and obese unfit men were 2.2 (P = 0.01) and 1.9 (P = 0.03) times more likely to die, respectively. Cardiorespiratory fitness altered the obesity paradox such that mortality risk was lower for both obese and nonobese men who were fit
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