Self-management of Initiations by Students Diagnosed with Autism

During prebaseline observations, three students diagnosed with autism were unable to make social initiations to another individual. The ability to make initiations would be considered a “pivotal response” in that it would allow an individual to come into contact with a wide variety of social reinforcement. A multiple-baseline design was implemented to measure the effects of a using a self-management package to teach the students to make social initiations. Two interventionists worked with each student to prompt and reinforce initiations. All students acquired social initiations during externally-determined reinforcement. The initiations were maintained when reinforcement changed from externally determined to a self-management system. The prompts to initiate and self-reinforce were faded over the course of the sessions. The use of self-management by the student led to less need for staff intervention. Implications from the literature are discussed.     

Is a Reasonable Attempt Reasonable? Shaping Versus Reinforcing Verbal Attempts of Preschoolers with Autism

The effectiveness of a language-training procedure that emphasized reinforcing vocal “reasonable attempts” (any response directed at an interventionist and within a broader class of correct responses) was compared with a procedure that emphasized shaping (reinforcing successive approximations that more closely resembled the target vocalization). Three preschoolers who had been diagnosed with autism spectrum disorders participated in the study. Data indicated that the children mastered vocal skills more rapidly when they learned through shaping than in the reasonable attempts condition. Implications for teaching children with autism spectrum disorders are discussed.     

Assessing Engineering Resilience for Systems with Multiple Performance Measures

Recently, efforts to model and assess a system's resilience to disruptions due to environmental and adversarial threats have increased substantially. Researchers have investigated resilience in many disciplines, including sociology, psychology, computer networks, and engineering systems, to name a few. When assessing engineering system resilience, the resilience assessment typically considers a single performance measure, a disruption, a loss of performance, the time required to recover, or a combination of these elements. We define and use a resilient engineered system definition that separates system resilience into platform and mission resilience. Most complex systems have multiple performance measures; this research proposes using multiple objective decision analysis to assess system resilience for systems with multiple performance measures using two distinct methods. The first method quantifies platform resilience and includes resilience and other “ilities” directly in the value hierarchy, while the second method quantifies mission resilience and uses the “ilities” in the calculation of the expected mission performance for every performance measure in the value hierarchy. We illustrate the mission resilience method using a transportation systems‐of‐systems network with varying levels of resilience due to the level of connectivity and autonomy of the vehicles and platform resilience by using a notional military example. Our analysis found that it is necessary to quantify performance in context with specific mission(s) and scenario(s) under specific threat(s) and then use modeling and simulation to help determine the resilience of a system for a given set of conditions. The example demonstrates how incorporating system mission resilience can improve performance for some performance measures while negatively affecting others.     

Mixtures of Toxic Agents and Attributable Risk Calculations

Calculations of attributable risks have attracted increasing interest recently. However, these efforts have been limited to mostly one agent, radiation, and no interactions with effects of other toxic agents have been taken into account. This paper outlines a generic approach to the calculation of attributable risks for an exposure to several toxic agents and interaction effects associated with them. In this calculation, the partition of interaction terms between the agents responsible is of particular importance. At present, there are no rules on how to assign equitable shares, so one methodology will be proposed and others discussed briefly. For one example of an assignment, the standard errors of the attributable risks are determined in terms of the uncertainties of the input parameters, thus setting the stage for a comparison of the different shares of responsibility.     

Maximization of reinforcement by two autistic students with accurate and inaccurate instructions

The present study examines maximization of reinforcement by two autistic individuals under conditions of no instructions, accurate instructions, and inaccurate instructions. Accuracy of instructions and magnitude of reinforcement for differential responding in a choice paradigm were systematically varied across phases. Subject one maximized reinforcement across all three conditions in seven experimental phases. Subject two maximized across these same seven phases, but also experienced three additional phases. In two of the additional phases, subject two maximized reinforcement. In a ninth phase, when reinforcement was intermittent rather than continuous, he failed to maximize reinforcement. Implications of the results for the controversies surrounding the concept of rule-governed behavior are discussed.

     

Trajectories of Sexual Risk From Middle Adolescence to Early Adulthood

Developmental trajectories of risky sexual behavior were identified in a multiethnic sample of 1,121 youth drawn from the Children of the National Longitudinal Survey of Youth data set (NLSY79). Group-based trajectory modeling of a composite index of sexual risk taking revealed four sexual risk groups from ages 16 to 22: low risk, decreasing risk, increasing risk, and high risk. The Low Risk group exhibited low levels of risk across the study period. The Decreasing Risk group had high levels of sexual risk in adolescence that declined in early adulthood. The Increasing Risk and High Risk groups showed distinct risk patterns during adolescence but converged in early adulthood. When compared with adolescents in the low-risk group, individuals in the other groups were more likely to be male, had mothers who had an early birth, were less likely to live with both biological parents in early adolescence, had higher risk proneness, and reported more negative peer pressure.     

The effects of schedules of reinforcement on instruction-following in human subjects with verbal and nonverbal stimuli

The Analysis of Verbal Behavior - The experiment reported here represents a partial replication of an experiment by Newman, Buffington, and Hemmes (in press) and analyzes responding in college...     

Supply Chains in Sub‐Saharan Africa: A Decision Support System for Small‐Scale Seed Entrepreneurs*

It is necessary to infuse a consistent supply of improved seed varieties into local sub‐Saharan African crop production to improve low crop yields. The best distribution channel for the improved seed varieties may be small‐scale commercial seed companies, but local entrepreneurs struggle to determine whether such businesses are viable. Using a multi‐echelon supply chain approach, a decision support system (DSS) was designed to help African seed entrepreneurs make informed decisions about small‐scale seed chain businesses. Specifically, entrepreneurs make decisions about where to locate seed enterprises, with which farmers to contract, and where to store seed. Optimization and simulation modeling are used to evaluate infrastructure variables such as distance, transportation cost, and storage loss and cost in three development level areas. Currently, the decision tool is used in Mozambique, Malawi, Kenya, and Tanzania. The model has supported the start‐up of at least 17 small seed companies that are now introducing improved seed varieties into villages and farms. The DSS applies decision science research in a humanitarian application and offers important managerial implications about supply chain infrastructure to nongovernmental organizations and humanitarian groups. Such applications are vital as groups such as USAID, the Gates Foundation, and the International Crops Research Institute for the Semi‐Arid Tropics (ICRISAT) continue to move toward micro‐enterprise, value chain, and market‐oriented development programs.     

A Systems-Crisis Approach to Family Treatment

This paper presents a model which integrates a wide range of possible interventions using family treatment and provides a method of differential decision making with regard to the intervention to be used in a given case. The model uses an ecological perspective and draws on concepts from general systems theory and crisis theory. A number of case examples are provided to demonstrate how the model has been applied in a clinical setting.