One of the defining characteristics of Autism Spectrum Disorder (ASD) is repetitive, rigid, or stereotyped patterns of behavior. A proposed approach to treating such patterns is to provide reinforcement for response variability. Though research demonstrates that the variability of responses can be influenced by contingencies of reinforcement, no studies have examined the effects of placing contingencies on different units of behavior. The purpose of this study was to examine effects of two modified percentile schedules on variety of completed drawings and individual lines drawn by students with ASD who had been referred for engaging in rigid patterns of behavior. For all three participants that completed drawing sessions, results indicated that drawing variability increased the most when reinforcement was contingent on the variability of the completed drawing, as opposed to a random ratio schedule of reinforcement or reinforcement being contingent on individual lines being varied.

Sedimentation is a fundamental operation in wastewater treatment works. A rational design of sedimentation tanks is currently achieved by plotting iso-percentile (iso-percentage) concentration removal profiles from flocculent settling data. A major drawback of the graphical iso-percentage method is that the iso-percentile lines are often manually interpolated and are mere hand drawn estimations. This is because the settling behaviour of sludge particles is highly non-linear. The manual analytical process is therefore very tedious, inaccurate and subjective. Hence, an optimised design of sedimentation tanks is necessary in order to eliminate the errors incurred during data analysis. In this study, a mechanistic iso-percentile flocculent model (referred to as the velocity flocculation model) is developed to simulate the behaviour of flocculating colloidal particles in turbid water. This model is based on the physical meanings of flocculent settling particles and on fractal theory. It is formulated to produce automated iso-percentile curves which are fundamental in the design of sedimentation tanks. The iso-percentile model was vertically integrated into a velocity model to produce a model expressing the velocity of particles as a function of removal rate. The velocity model has an obvious advantage over the iso-percentile model in that it is easy to contextualize. It can be reverted back to the iso-percentile trajectory analysis eliminating the need for extensive data interpolation and may in future eliminate the need for settling column analysis altogether. In the current study, the integrated velocity form is used to predict instantaneous flocculent settling velocity of fine suspended particles under near quiescent conditions. This is vital since it is difficult to obtain velocity values in-situ or directly from sedimentation tanks. Model validity and competency was tested by a direct comparison with existing literature models, such as Ozer’s model and Ramatsoma and Chirwa’s model. Model comparison was based on the goodness of fit, the least sum of square errors and mathematical consistency with known flocculent settling behaviour. The newly developed iso-percentile model achieved a more accurate simulation of physical experimental data, did not violate any of the mathematical constraints and yielded lower sum of square errors than originally achieved by Ozer and Ramatsoma and Chirwa. Notably, the proposed velocity model offers a distinctive advantage over conventional interpolated-iso-percentile based models which are prone to numerical errors during interpolation. Its performance (velocity model) was compared against Je and Chang’s velocity model. Higher velocity values were observed for the new model than for Je and Chang’s model implying that empirically based models would tend to under-predict the velocity values. The model developed in this study brings us one step closer to achieving full automation of the settling tank and clarifier design. / Dissertation (MEng)--University of Pretoria, 2013. / gm2014 / Chemical Engineering / unrestricted

Title: Evaluation of overweight and obesity in children of younger school age Objectives: The aim of this work is to evaluate the body compositon of a sample of children of younger school age. Another intention is to find out the preferences od spending free time and wheter the choice of leasure activities is determinated by overweight and obesity. Methods: In my theses I used a quantitative method of data collection using a survey. The survey is anonymous and was compiled on the basis of knowledge from the theoretical part. The target group is children of younger school age from Prague schools. The obtained BMI values ​​will be compared with the tables and in children with higher BMI values ​​the individual answers will be analyzed in more detail. This method should indicate the possible cause of elevated BMI values. Results: The results of the survey showed, it was found that Below-avarage (42 %) and average (53 %) BMI values were most often found in most children. Most children with higher BMI values aet breakfast regularly (71 %), but physical activities in the weekend program are included irregularly (78 %). Secondary education was most often mentioned among the parents of these children (60 %). Keywords: overweight, obesity, BMI, percentile graphs, lifestyle

Growth is sensible detector of long-term health condition of children. Observation of growth by means of growth charts are an important aid for practise of paediatricians. This work assesses an influence of long-term breastfeeding on growth of children from birth to 2 years of age and compares the growth of these children with the world study (MGRS) and Czech study (5./6. CAV). The basis for my study was formed from the set of children measured in Dr. Mottlova's office. It was detected, that long-term breastfeeding significantly influences the length and weight of children, when it interacts with age of children. Breast-fed children were smaller (0,6 cm, 1,1 cm, 0,9 cm) and lighter (250 g, 400 g, 210 g) then formula-fed children in 6th , 12th and 18th month of age. The comparison between our study, MGRS and 5./6. CAV proved, that the growth of children in our study is more similar to 5./6.CAV. Key words: growth, human milk, breastfeeding, growth standards, percentile charts.

There has been an upward trend in obesity among African American (AA) adolescents over the last 2 decades. While parenting characteristics (e.g., styles and practices) are linked to adolescent eating habits and weight status, related research has focused on European American children from 2-parent middle-class households or economically disadvantaged AA children from single mother households. The purpose of this quantitative secondary data analysis was to investigate the relationship between parenting characteristics on the weight status of adolescents aged 12 to 17 years (n = 325) among a broader population of AA mothers and fathers residing both inside and outside of the home. The social cognitive theory, widely used in obesity intervention research, was the framework used to explore parental behaviors that contribute to adolescent weight status and health. The National Longitudinal Survey of Youth 1997 was used to examine the relationship between parenting characteristics on adolescent weight status, as measured by body mass index (BMI) percentile. Statistical analysis included the Kruskal-Wallis Test, Mann-Whitney U, Spearman rho correlation, and hierarchical multiple regression. Results indicated no significant relationships between parenting characteristics and adolescent BMI percentiles as determined by Kruskal-Wallis and multiple regression analysis when controlled for sociodemographic variables. Study findings indicate that variables beyond parenting practices, such as urban/rural residence, must be considered to explain BMI and weight status among AA adolescents. Largely, this study increased knowledge on AA parenting characteristics and promotes education and social awareness of the continued weight epidemic that plagues AA children in the United States.

The motivation behind the project was to update the Livermore Software Technology Corporation (LSTC) Hybrid III 95th percentile finite element model, such that the neck assembly response under varying simulated loading conditions equals that of the federally regulated Hybrid III 95th percentile anthropomorphic testing device (ATD). The family of Hybrid III crash test dummies approximate the physical properties and response of the human body in a frontal automotive crash. The Hybrid III is used to assess the effectiveness of vehicle restraint systems. LSTC offers Hybrid III finite element models for use in their Multiphysics simulation software package, LS-DYNA. The Hybrid III models are used as cost-effective alternative to physical crash tests in the development of vehicle crashworthiness. However, the neck response of the LSTC Hybrid III 95th percentile model in simulation was poorly correlated to that of the physical Hybrid III neck in corresponding tests. The source of the dissimilarity was inadequate dimensions, element behavior, and material properties of the neck. To improve correlation to the physical ATD, a number of modifications were made to the LSTC Hybrid III 95th percentile neck. Development of the neck model began with improvements in mass and geometry. Element formulation and element discretization were altered to improve model durability and accuracy. A mesh convergence study and simulation under extreme-severity loading were completed to validate the foregoing model alterations. Test data from a physical compression test and NASA-performed Neck Sled Tests were collated with data from simulation to adjust material type and material properties. The model was further calibrated according to Code of Federal Regulations neck calibration test response requirements. The resulting neck model developed in LS-DYNA exhibited improved dynamic characteristics and reliability under both low and high-severity loading. Computational efficiency was enhanced along with model tendency to normally terminate under excessive loading. The updated model moreover demonstrated consistent element behavior and realistic feedback in bending. The revised neck model will be adopted by NASA for use in predicting potential occupant injury during spacecraft landing. A similar model with reworked material properties attuned to higher loading will be implemented into the full consumer version of the Hybrid III 95th percentile model for employment in high-severity frontal crash simulation.

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In an effort to adapt a prize-based attendance and abstinence reinforcement program to the group therapy modality typically found in community substance abuse treatment, this study applied a contingency management (CM) procedure to behavior outcomes of the group as a whole. An algorithmic shaping percentile schedule was used to establish the outcome criteria determining group access to prize bowl drawings. Both the shaping schedule and hypothesized positive social support secondary to interdependent group contingencies aimed to initiate cocaine abstinence among cocaine abusing methadone-maintained participants having initial low rates of cocaine abstinence. In a multiple baseline across behaviors with reversals design, the procedure was applied to four target behaviors in sequence: incentive group attendance, urinalysis appointment attendance, opiate and cocaine abstinence. Results demonstrated clear improvement in group attendance during the shaping schedules. Effects on opiate abstinence were promising but not definitive; an increase in magnitude of reinforcement yielded a better response. There were no effects on cocaine abstinence using the percentile schedules tried. When shaping was conducted by an experienced psychologist in conjunction with an average 4-fold increase in reinforcer magnitude, 55% achieved some abstinence (compared to 18% in baseline). Participants were monitored for safety due to concern about coercion; no instances of physical violence occurred and infrequent instances of verbal negativity were managed using typical outpatient procedures. Results indicate that interdependent group CM is efficacious for attendance, and a feasible and acceptable procedure with appropriate monitoring. Future studies are needed to determine effective and appropriate shaping and reinforcement schedules in group CM to increase drug abstinence. / Educational Psychology