Bachelor of Social Work (BSW) Students' Prior Sexual Abuse Victimization

This paper reports findings of an exploratory study surveying 61 students about their prior child sexual abuse victimization. Bachelor of Social Work (BSW) students were surveyed at the beginning and end of a child abuse course and results indicated that 19.7 % of the students reported being sexually abused during childhood. Results also indicated that taking a child abuse course may increase BSW students' self‐awareness regarding prior victimization. The paper discusses how prior child sexual abuse victimization can affect social work students, education, and practice.     

Highly selective biomechanical separation of cancer cells from leukocytes using microfluidic ratchets and hydrodynamic concentrator

The separation of cells based on their biomechanical properties, such as size and deformability, is important in applications such as the identification of circulating tumor cells, where morphological differences can be used to distinguish target cancer cells from contaminant leukocytes. Existing filtration-based separation processes are limited in their selectivity and their ability to extract the separated cells because of clogging in the filter microstructures. We present a cell separation device consisting of a hydrodynamic concentrator and a microfluidic ratchet mechanism operating in tandem. The hydrodynamic concentrator removes the majority of the fluid and a fraction of leukocytes based on size, while the microfluidic ratchet mechanism separates cancer cells from leukocytes based on a combination of size and deformability. The irreversible ratcheting process enables highly selective separation and robust extraction of separated cells. Using cancer cells spiked into leukocyte suspensions, the complete system demonstrated a yield of 97%, while enriching the concentration of target cancer cells 3000 fold relative to the concentration of leukocytes.     

Using the standard Wald confidence interval for a population proportion hypothesis test is a common mistake

Employing a Wald confidence interval to test hypotheses about population proportions could lead to an increase in Type I or Type II errors unless the hypothesized value, p0, is used in computing its standard error rather than the sample proportion.     

Failure-to-thrive, maltreatment and the behavior and development of 6-year-old children from low-income, urban families: a cumulative risk model

OBJECTIVE: A cumulative risk model was used to examine the relationship among failure-to-thrive (FTT), maltreatment, and four aspects of children's development: cognitive performance (standardized testing), adaptive functioning at school, and classroom behavior (teacher report), and behavior at home (maternal report). METHOD: The sample included 193 6-year-old children and their families, recruited from pediatric clinics serving inner-city, low-income, primarily African-American families, who were part of a longitudinal investigation of child development and maltreatment. Four risk groups were formed based on their growth and maltreatment history: neither FTT nor Maltreatment, FTT Only, Maltreatment Only, and both FTT and Maltreatment. FTT was defined as a deceleration in weight gain (weight-for-age below the 5th percentile) prior to 25 months of age among children born at term with birth weight appropriate for gestational age. Maltreatment was defined as having at least one report to CPS for neglect, physical abuse and/or sexual abuse. RESULTS: Risk status was negatively associated with each of the four developmental outcomes. Children with a history of both FTT and maltreatment had more behavior problems and worse cognitive performance and school functioning than children with neither risk factor. Children with only one risk factor (either FTT or maltreatment) achieved intermediate scores. CONCLUSIONS: Findings support a cumulative risk model as being more detrimental to children's development than the presence of a single risk factor alone, consistent with theories linking the accumulation of environmental risks to negative consequences. These results underscore the importance of interventions to prevent both FTT and maltreatment during children's early years.     

Stability of arithmetic disability subtypes

Cross-sectional research has identified subtypes of children with learning disabilities who may have distinctive cognitive ability patterns. This study examined the stability over 19 months of academic subtyping classifications for 80 children ages 9 to 13 representing four subtypes of arithmetic disabilities (AD), using three criteria for learning disability identification. Approximately half of the sample retained AD regardless of identification method. Children with pervasive deficits in arithmetic, reading, and spelling displayed the greatest subtype stability. Only one third of the children with the other subtypes, including those with isolated arithmetic deficits, retained their original subtypes. Thus, drawing conclusions and making recommendations based on academic subtyping at a single point in time may be unwise.     

Inter-level Scaffolding and Sequences of Representational Activities in Teaching a Chemical System with Graphical Simulations

Chemistry knowledge can be represented at macro-, micro- and symbolic levels, and learning a chemistry topic requires students to engage in multiple representational activities. This study focused on scaffolding for inter-level connection-making in learning chemistry knowledge with graphical simulations. We also tested whether different sequences of representational activities produced different student learning outcomes in learning a chemistry topic. A sample of 129 seventh graders participated in this study. In a simulation-based environment, participants completed three representational activities to learn several ideal gas law concepts. We conducted a 2 × 3 factorial design experiment. We compared two scaffolding conditions: (1) the inter-level scaffolding condition in which participants received inter-level questions and experienced the dynamic link function in the simulation-based environment and (2) the intra-level scaffolding condition in which participants received intra-level questions and did not experience the dynamic link function. We also compared three different sequences of representational activities: macro-symbolic-micro, micro-symbolic-macro and symbolic-micro-macro. For the scaffolding variable, we found that the inter-level scaffolding condition produced significantly better performance in both knowledge comprehension and application, compared to the intra-level scaffolding condition. For the sequence variable, we found that the macro-symbolic-micro sequence produced significantly better knowledge comprehension performance than the other two sequences; however, it did not benefit knowledge application performance. There was a trend that the treatment group who experienced inter-level scaffolding and the micro-symbolic-macro sequence achieved the best knowledge application performance.     

Preschool peer communication skills: the role of social status and interaction context

The purpose of this study was to investigate the relation between social status and discourse skills in preschool children. Using peer nominations, 48 acquainted preschool children were classified as liked, disliked, or low impact. Children were videotaped in freeplay interactions in which one child entered the play of a pair of same-sex peers. Social status differences were found primarily in skills contributing to coherent discourse. Specifically, liked children were more inclined to direct their initiations clearly, to speak to both interaction partners rather than just one, to respond contingently to others, to acknowledge others, and to reinitiate when rejecting. Liked children were also better able to adapt to the differing social demands of entry versus nonentry contexts in that they were more likely to give information and less likely to express their feelings when entering a group. Deficits in communication skill were greater for disliked children than for low-impact children. Results indicate that communication skills that contribute to coherent discourse are fundamental to social interaction and may influence young children's peer acceptance.