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Nearly one million total hip and knee arthroplasties (THA/TKA) are performed annually in the United States, with most patients discharged home and prescribed home exercise programs (HEPs) to enhance lower extremity function. Traditional paper-based HEPs, while accessible and low-cost, often lack engagement and real-time feedback, which are critical for adherence and performance optimization. Extended reality (XR) and telehealth (TH) systems offer promising solutions, combining engagement and feedback, though each has limitations. To address these gaps, we designed and executed a pilot study that compared exercise performance in individuals with THA/TKA using a conventional paper-based HEP versus a proof-of-concept system, dubbed Tele-PhyT, that included the ideal characteristics of a future XR technology that would enable seamless HEP-TH systems, with robust marker-less full body tracking, real-time visual feedback, and performance quantification. The pilot study used a randomized cross-over design and targeted two types of users: therapists and patients. Participants favored Tele- PhyT for its real-time feedback and ease of use, and noted its potential to improve HEP adherence and exercise accuracy., Comment: In Proceedings of the 3rd Workshop on XR Technologies for Healthcare, Wellbeing, and Medicine, IEEE VR Conference, March 8-12, 2025

The goal of the current pilot study was to examine the effects of bystander intervention training on a sample of 27 high school students who were selected by their peers as opinion leaders. Measures of bystander intervention knowledge, attitudes, and behaviors were included in the within-subjects design. Sixteen of the students also participated in focus groups to provide feedback about their experiences with the training. Results showed that participating students reported increases in knowledge about bullying and sexual harassment, confidence in intervening, acceptance of responsibility, knowing what to do, and acting to intervene (including direct intervention, providing support, and reporting to an adult) from pre-to posttest. Themes from focus groups indicated that students found the training relevant and helpful, particularly for focusing on both bullying and sexual harassment and for providing opportunities to learn and practice multiple intervention strategies. Barriers to intervening based on the type of violence (e.g., physical vs. relational or verbal) and relationship with the people involved were also themes. Directions for future research and implications for practice, such as focusing on dissemination to the larger student body and implementing bystander intervention training within the context of a positive school climate that emphasizes social and emotional competencies, are discussed. [This paper will be published in "Journal of Prevention and Health Promotion."]

This study investigated the extent to which adolescents' personal normative attitudes (also referred to as personal norms) and perceived peer norms regarding bullying, sexual harassment, and bystander intervention predicted each step of the five-step bystander intervention model (i.e., Notice, Interpret, Accept Responsibility, Know how to Help, Act) for bullying and sexual harassment among two-hundred thirty-three high school students in the Northeastern United States. Interaction effects of gender, personal norms, and perceived peer norms were also assessed. As predicted, perceived peer norms moderated the relations between personal norms and all five bystander intervention steps. However, some effects differed by gender and some differed in direction from predictions. Students who were more anti-bullying/harassment scored higher on some bystander intervention steps when they also perceived their peers to be more anti-bullying and harassment, with some models showing gender differences between male and female students. Personal and perceived peer norms are related to adolescents' engagement in the bystander intervention model, suggesting that both norms should be targets of interventions encouraging youth to intervene in incidents of bullying and sexual harassment.

Bullying, cyberbullying, and sexual harassment can be impacted by both personal attitudes and perceived social norms, although few empirical studies on this topic have been conducted with high school students. In this cross-sectional study, 233 high school students completed measures about personal normative attitudes, perceptions of peer norms, and perpetration of bullying, cyberbullying, and sexual harassment. Consistent with social norms theory, students perceived themselves to hold more prosocial (i.e., anti-bullying/anti-sexual harassment) personal normative attitudes than they perceived the typical student in their school to hold (i.e., peer norms). Path analyses revealed that students' personal normative attitudes (e.g., anti-bullying/anti-harassment) were negatively related to their bullying, cyberbullying, and sexual harassment perpetration, although perceived peer norms were negatively related to sexual harassment perpetration only. Multiple-group path analysis revealed significant gender differences. Personal normative attitudes related to females' behavior for all forms of perpetration and only sexual harassment and cyberbullying for males (with more anti-bullying/anti-harassment attitudes relating to less perpetration), although associations for males were stronger. Perceived peer norms related to bullying perpetration for males only. Results are discussed with regard to social-cognitive and peer contextual factors and implications for social norms interventions. [This is the online first version of an article published in "School Psychology."]

Lateralization is ubiquitous in vertebrate brains which, as well as its role in locomotion, is considered an important factor in biological intelligence. Lateralization has been associated with both poor and good performance. It has been hypothesized that lateralization has benefits that may counterbalance its costs. Given that lateralization is ubiquitous, it likely has advantages that can benefit artificial intelligence. In turn, lateralized artificial intelligent systems can be used as tools to advance the understanding of lateralization in biological intelligence. Recently lateralization has been incorporated into artificially intelligent systems to solve complex problems in computer vision and navigation domains. Here we describe and test two novel lateralized artificial intelligent systems that simultaneously represent and address given problems at constituent and holistic levels. The experimental results demonstrate that the lateralized systems outperformed state-of-the-art non-lateralized systems in resolving complex problems. The advantages arise from the abilities, (i) to represent an input signal at both the constituent level and holistic level simultaneously, such that the most appropriate viewpoint controls the system; (ii) to avoid extraneous computations by generating excite and inhibit signals. The computational costs associated with the lateralized AI systems are either less than the conventional AI systems or countered by providing better solutions., Comment: 13 pages, 14 figures

The majority of computer vision algorithms fail to find higher-order (abstract) patterns in an image so are not robust against adversarial attacks, unlike human lateralized vision. Deep learning considers each input pixel in a homogeneous manner such that different parts of a ``locality-sensitive hashing table'' are often not connected, meaning higher-order patterns are not discovered. Hence these systems are not robust against noisy, irrelevant, and redundant data, resulting in the wrong prediction being made with high confidence. Conversely, vertebrate brains afford heterogeneous knowledge representation through lateralization, enabling modular learning at different levels of abstraction. This work aims to verify the effectiveness, scalability, and robustness of a lateralized approach to real-world problems that contain noisy, irrelevant, and redundant data. The experimental results of multi-class (200 classes) image classification show that the novel system effectively learns knowledge representation at multiple levels of abstraction making it more robust than other state-of-the-art techniques. Crucially, the novel lateralized system outperformed all the state-of-the-art deep learning-based systems for the classification of normal and adversarial images by 19.05% - 41.02% and 1.36% - 49.22%, respectively. Findings demonstrate the value of heterogeneous and lateralized learning for computer vision applications., Comment: 13 pages, 5 figures

Poverty shapes the experience of more than twelve million children in the United States. To further an understanding of the relationship between poverty and school performance in South Carolina public schools, we investigated the association of high and low poverty levels with a range of state report card variables for three school levels: elementary, middle, and high schools. In this study, we considered variables in four categories: academic achievement/outcomes, student engagement, classroom environment, and student safety. An analysis of 1163 public schools in 88 school districts and state-operated programs revealed that for different school levels, significant differences by poverty level exist in these categories. We conclude with recommendations for policymaking, intervention programs, and funding opportunities to support high-poverty schools, and ultimately aiming to narrow the gaps of school performance due to poverty.

Representation and control of the dynamics of stigmergic substances used by bio-inspired approaches is a challenge when applied to robotics. In order to overcome this challenge, this work proposes a model to coordinate swarms of robots based on the virtualisation and control of these substances in a local scope. The model presents a new pheromone modelling, which enables the decentralisation and asynchronicity of navigation decisions. Each robot maintains an independent virtual pheromone map, which is continuously updated with the robot's deposits and pheromone evaporation. Moreover, the individual pheromone map is also updated by aggregating information from other robots that are exploring nearby areas. Thus, individual and independent maps replace the need of a centralising agent that controls and distributes the pheromone information, which is not always practicable. Pheromone information propagation is inspired by ants' vibroacoustic communication, which, in turn, is characterised as an indirect communication through a type of gossip protocol. The proposed model was evaluated through an agent simulation software, implemented by the authors, and in the Webots platform. Experiments were carried out to validate the model in different environments, with different shapes and sizes, as well as varying the number of robots. The analysis of the results has shown that the model was able to perform the coordination of the swarm, and the robots have exhibited an expressive performance executing the surveillance task., Comment: 26 pages, 15 figures

The dynamical system described herein uses a hybrid cellular automata (CA) mechanism to attain reversibility, and this approach is adapted to create a novel block cipher algorithm called HCA. CA are widely used for modeling complex systems and employ an inherently parallel model. Therefore, applications derived from CA have a tendency to fit very well in the current computational paradigm where scalability and multi-threading potential are quite desirable characteristics. HCA model has recently received a patent by the Brazilian agency INPI. Several evaluations and analyses performed on the model are presented here, such as theoretical discussions related to its reversibility and an analysis based on graph theory, which reduces HCA security to the well-known Hamiltonian cycle problem that belongs to the NP-complete class. Finally, the cryptographic robustness of HCA is empirically evaluated through several tests, including avalanche property compliance and the NIST randomness suite., Comment: 34 pages, 12 figures

Although there have been extensive investigations characterizing cavitation phenomenon in fuel injectors, much is still unknown about the mechanisms driving cavitation-induced erosion, and how these complicated physics should be represented in a model. In lieu of computationally expensive fluid-structure interaction modeling, the Eulerian mixture modeling approach has been accepted as an efficient means of capturing cavitation phenomena. However, there remains a need to link the erosive potential of cloud collapse events with the subsequent material deformation and damage of neighboring surfaces. Even though several cavitation erosion indices have been proposed in the literature, no single metric has been identified as universally applicable across all injector-relevant conditions. The objective of this work is to identify parameters that characterize the erosive potential of cavitation cloud collapse mechanisms that are likely to occur within injector orifices. While a commonly employed cavitation erosion metric, namely the maximum local pressure, was found to provide indications of potential sites for pitting and material rupture from single impact events, no additional information could be determined regarding the material erosion process. To improve representation of the incubation period within the cavitation erosion process, a new metric was derived based on cumulative energy absorbed by the solid material from repeated hydrodynamic impacts. Through evaluation of predicted cavitation cloud collapse events in a channel geometry against available experimental data, the stored energy metric yielded insight into the erosive potential of recorded impact events. The stored energy metric provided a means to accurately predict the influence of flow conditions on the incubation period before material erosion. ..., Comment: 9 pages, 6 figures, ICLASS 2018, 14th Triennial International Conference on Liquid Atomization and Spray Systems, Chicago, IL, USA, July 22-26, 2018

Although there have been extensive experimental and computational investigations in characterizing cavitation phenomenon in both diesel and gasoline direct injectors, much is still unknown about the mechanisms driving cavitation-induced erosion, and how this complicated fluid-structure interaction should be modeled. To explore current modeling capabilities, a numerical investigation was conducted within the CONVERGE modeling framework to assess proposed cavitation erosion metrics in the literature, and their link to the predicted cavitation cloud collapse mechanism. The multiphase flow within the Winklhofer Throttle U geometry was modeled using a compressible mixture model, where phase change was represented using the Homogeneous Relaxation Model (HRM) and the turbulent flow evolution was modeled using a dynamic structure approach for Large Eddy Simulations (LES). After comparing the model predictions against available experimental data, representative condensation events and potential cavitation erosion sites were identified. The cavitation cloud structures responsible for potential material damage were visualized through the evolution of the vorticity field. For the modeled throttle geometry, it was found that the horseshoe cloud implosion mechanism was predicted to occur and generate excessive impact loads at the throttle boundary., Comment: 5 pages, 4 figures, 10th International Symposium On Cavitation (CAV2018)

The results of a large-scale randomized controlled trial of Conjoint Behavioral Consultation (CBC) on student outcomes and teacher-parent relationships in rural schools are presented. CBC is an indirect service delivery model that addresses concerns shared by teachers and parents about students. In the present study, the intervention was aimed at promoting positive school-related social-behavioral skills and strengthening teacher-parent relationships in rural schools. Participants were 267 students in grades K-3, their parents, and 152 teachers in 45 Midwest rural schools. Results revealed that, on average, improvement among students whose parents and teachers experienced CBC significantly outpaced that of control students in their teacher-reported school problems and observational measures of their inappropriate (off-task and motor activity) and appropriate (on-task and social interactions) classroom behavior. In addition, teacher responses indicated significantly different rates of improvement in their relationship with parents in favor of the CBC group. Finally, the teacher-parent relationship was found to partially mediate effects of CBC on several student outcomes. Unique contributions of this study, implications of findings for rural students, study limitations and suggestions for future research are discussed. [This article was published in "Journal of School Psychology," v61 p33-53 2017.]

Although researchers have explored the impact of instructional coaching and named possible elements believed essential to effective coaching, there has yet to emerge from the literature a coherent model of those essential elements ("active ingredients"). This qualitative study sought to identify those elements through a systematic process beginning with a synthesis of current coaching literature to compile a list of ingredients. Using a modified grounded theory approach, this list was then validated through semi-structured focus group data of teachers and triangulated with focus group data provided by instructional coaches to create a conceptual framework of coaching. Future coaching research can build upon this framework through empirically testing those key components that are necessary for effective coaching.

National and state educational mandates require students achieve proficiency in not only science content, but also "science inquiry", or those process skills associated with science (National Research Council, 2011; Next Generation Science Standards, 2013). Science inquiry instruction has been shown to improve student achievement and process skills (e.g., Llewellyn, 2002; Schroeder, Scott, Olson, Huang, & Lee, 2007; Minner, Levy, & Century, 2010). Guided scientific inquiry is a student-centered, teacher-facilitated approach to science instruction where students are guided toward, but not directly presented, scientific concepts. Students are led by the teacher to develop the concept (Trowbridge, Bybee, & Powell, 2004). Guided science inquiry has been found effective in promoting student achievement (e.g., Wilson, Taylor, Kowalski, & Carlson, 2010). However, research has not yet specifically examined the value of guided scientific inquiry among students drawn from the special education population. This study sought to answer two research questions. First, how did teachers involved in a study examining implementation of guided science inquiry qualitatively describe their experience implementing guided science inquiry among their students from special education populations? Second, did teachers find guided science inquiry effective to use with students from special education populations? This study sought to answer two research questions. First, how did teachers involved in a study examining implementation of guided science inquiry qualitatively describe their experience implementing guided science inquiry among their students from special education populations? Second, did teachers find guided science inquiry effective to use with students from special education populations? The results suggest that guided science inquiry instruction can be effectively implemented with students from the special education population. The majority of teacher responses suggested that a guided science inquiry approach provides these students with greater understanding, inclusion, and engagement with their science lessons than do traditional instructional methods. Guided science inquiry's flexibility allows for differentiated instruction. Limited concerns with the approach reported for these students included a need to adapt instruction in order to meet their needs and difficulties among students grasping its occasionally abstract structure.

Superconductivity in anti-PbO-type iron chalcogenides Fe1-xTe1-ySey (x = 0, 0.1, y = 0.1 0.4) depends on the amount (x) of interstitial iron atoms located between the FeTe1-ySey layers. Non-superconducting samples of nominal Fe1.1Te1-ySey convert to superconductors with critical temperatures up to 14 K after annealing at 300{\deg}C in an oxygen atmosphere. The process is irreversible upon subsequent hydrogen annealing. Magnetic measurements are consistent with the formation of iron oxides suggesting that oxygen annealing preferably extracts interstitial iron from Fe1-xTe1-ySey which interfere with superconductivity.

Children who exhibit disruptive behavior often do so across multiple settings (e.g., home and school) and are vulnerable to many negative outcomes, including low achievement scores and academic grades, high school dropout, and increased school suspensions. Family-school partnership interventions, which are grounded in ecological theory, are highly correlated with many positive outcomes for students, families, and teachers. Experimental studies with families as collaborators have been found to improve students' behavioral functioning and decrease disruptive behaviors. There is a lack of empirical research on family-school connections in rural settings, hindering the ability to understand the impact of family-school partnerships on rural schools, families, and students. Rural parents interact with their children and teachers regarding school less often than parents in other geographic areas. Conjoint behavioral consultation (CBC) may address barriers and create meaningful partnerships between rural parents and teachers. CBC is a structured indirect form of support in which teachers and parents work together to promote adaptive behaviors and decrease disruptive behaviors. The following questions were researched for this report: (1) What are the preliminary effects of CBC in rural communities on behavioral and social-emotional outcomes of students with or at risk of developing behavioral disorders?; and (2) What are the preliminary effects of CBC in rural communities on parent and teacher practices, relationships, engagement, and beliefs about family-school partnerships? Ninety kindergarten through 3rd grade students and their parents (n = 90) and teachers (n = 54) from 20 schools in Midwestern rural areas participated in this research. Participating students were identified by teachers as having disruptive behavior concerns. Within each CBC-assigned classroom, a consultant met with a teacher and parents of 1 to 3 students for CBC meetings via a 4-stage process operationalized by semi-structured conjoint interviews. Results suggest promising effects of CBC for teachers, parents, and students in rural settings. [The paper was presented originally by the authors at the 2013 annual meeting of the National Association of School Psychologists.]

The purpose of this study was to build on this body of research by exploring the differences in factors related to overall job satisfaction by faculty rank. Because faculty from one institution were used in the study and the data source included results from a survey taken by only some of the faculty, generalizability of the findings may be limited. The findings of this study are meant to be utilized by the administration of the University of Minnesota to further understand the job satisfaction factors of the faculty. Therefore, this research study was designed to be practical and useful to a specific audience, but may also be helpful in furthering the general understanding of the issue. Data for this study included the results of the PULSE survey completed by faculty at the University of Minnesota, Twin Cities Campus in the spring of 2008. Out of 3,671 faculty members who were provided the opportunity to take the survey, 1,253 completed it, for a response rate of 34.1%. The research question under consideration in this study was whether factors related to overall job satisfaction varied among different groups of faculty and faculty-like employees of the University, categorized by rank. Based on the stepwise multiple linear regression analyses conducted on the data from the 2008 PULSE survey, there do appear to be differences in the satisfaction factors for faculty with the rank of academic professional, instructor, assistant professor, associate professor, and professor. Satisfaction with university characteristics appeared to be an important factor for tenured and tenure-track faculty, but not for faculty with the rank of academic professional and instructor. Satisfaction with pay level shared a relationship with overall job satisfaction for all faculty ranks but assistant professors, though possibly to different degrees. If a thorough understanding of the factors that relate to overall job satisfaction for all faculty is desired, considering the varying needs of the different groups is critical to creating a complete picture. A bibliography is included. (Contains 9 tables.)

The vast majority of connections between complex disease and common genetic variants were identified through meta-analysis, a powerful approach that enables large samples sizes while protecting against common artifacts due to population structure, repeated small sample analyses, and/or limitations with sharing individual level data. As the focus of genetic association studies shifts to rare variants, genes and other functional units are becoming the unit of analysis. Here, we propose and evaluate new approaches for meta-analysis of rare variant association. We show that our approach retains useful features of single variant meta-analytic approaches and demonstrate its utility in a study of blood lipid levels in ~18,500 individuals genotyped with exome arrays.

This study explores the possibility of measuring a specific instructional strategy using statistical methods based on item response theory. It measures teachers' instructional practices using the same rigorous statistical techniques now applied to most large-scale assessments of student achievement. It specifically examines teachers' use of pedagogical techniques consistent with those espoused by the national standards-based reform movement in science. Data come from a nationally representative sample of public school eighth graders and their teachers from the 1996 National Assessment of Educational Progress. The paper describes: "The Standards Movement; "The Case of Science"; "Data on Teacher Instructional Practices"; "A Descriptive Portrait of Middle School Science Instruction"; "The Item-Response Theory (IRT) Approach--A Primer" (the basic data matrix, introduction to IRT parameters, and advantages of an IRT approach); and "IRT Analysis for Standards-Based Science Instruction" (a model-building strategy, stages in model-building, a generalized model of standards-based science instruction, and placing standards-based instruction in context). Results suggest there are many benefits to applying IRT models to instruction. The diagnostic information produced by the IRT analyses provided an empirical means to systematically identify practices that did not appear to align conceptually with the construct of standards-based instruction. (Contains 37 references.) (SM)

Using 232 studies, this meta analysis reviewed the research on the achievement effects of the nationally disseminated and externally developed school improvement programs known as "whole-school" or "comprehensive" reforms. In addition to reviewing the overall achievement effects of comprehensive school reform (CSR), the meta analysis considered the specific effects of 29 of the most widely implemented models. It also assessed how various CSR components, contextual factors, and methodological factors associated with the studies mediate the effects of CSR. The analysis concludes that CSR is still an evolving field and that there are limitations on the overall quantity and quality of the research base. The overall effects of CSR, though, appear promising and the combined quantity, quality, and statistical significance of evidence from three of the models in particular set them apart from the rest. Whether evaluations are carried out by the developer or by third-party evaluators and whether these evaluators use one-group pre-post designs or control groups are especially important factors for understanding differences in CSR effects. Schools implementing CSR models for five years or more showed particularly strong effects, but the models benefited equally schools of higher and lower poverty levels. A long-term commitment to research-proven educational reform is needed to establish a strong marketplace of scientifically based models capable of bringing comprehensive reform to the nations schools. One appendix lists studies included in the meta analysis, and the other discusses CSR design characteristics. (Contains 1 figure, 5 tables, and 74 references.) (SLD)

Teacher education programs nationwide are required by state and federal governments to maintain comprehensive student records of all current and graduated students in their programs. A private, mid-sized university established a faculty team to analyze record-keeping procedures to comply with these government requirements. The team's mandate was to establish an effective and efficient procedure for obtaining and handling student records. The lack of uniform standards in the record-keeping process produced inconsistent and incomplete data. The then current data-keeping procedure was paper-based and inefficient. A database management system based on Microsoft Access was developed and implemented to capture, store, and organize student data. Using the system, the education program developed and maintained electronic student files that provide the data needed for required reports. Additionally, the database management system provides several other benefits to the university's education department. (Author/SM)

This report presents results from an analysis of the long-term benefits and costs of Success for All (SFA), a school reform program that focuses on promoting early reading success among educationally at-risk students. The program was piloted and implemented in Baltimore elementary schools. This analysis tracks the educational outcomes through eighth grade for the original SFA students and for a quasi-experimental, untreated control group of students from matched comparison schools. The study also examines differential costs associated with SFA and control students' schooling through eighth grade. Finally, it compares the relative cost-effectiveness of SFA and three other initiatives (Perry Preschool, the Abecedarian Project, and the Tennessee class-size experiment). Data on the 1986-87 through 1998-99 school years were collected from computerized files provided by the Baltimore City Public School System. Results indicated that relative to controls, SFA students completed eighth grade at a younger age, at the same educational expense, and with better achievement outcomes, fewer special education placements, and less frequent retentions. Comparison to the other interventions suggests that SFA provides the strongest educational benefits for the dollar, though no single program may be relied upon as the "great equalizer." (Contains 45 references.) (SM)

There is evidence that diesel exhaust causes cancer and premature death, and also exacerbates asthma and other respiratory illness. Noting that the vast majority of the nation's school buses run on diesel fuel, this report details a study examining the level of diesel exhaust to which children are typically exposed as they travel to and from school. Further, the report is intended to inform parents, administrators, and policy makers of the cleaner alternatives that are readily available. The air was continuously sampled inside four elementary school buses that drove an actual bus route of about 45 minutes for 4 to 6 repetitions over 5 hours. Nearly 20 hours of sampling results were obtained. Findings indicated that children riding inside a diesel school bus, even buses not emitting significant amounts of black smoke, may be exposed to as much as four times the level of toxic diesel exhaust as someone standing or riding beside the bus, translating to from 23 to 46 times the cancer risk level considered significant under federal law. The report details the harmful health impact of diesel exhaust, describes cleaner alternatives being used by an increasing number of school districts, and notes that short-term measures such as particulate traps have not been proven to decrease risks to children and are available in only a limited number of areas. Funding sources are identified to help public and private schools purchase cleaner alternatives. The report concludes with recommendations for districts, government agencies, and parents. The report's eight appendices include a study protocol, an estimation of potential cancer risk to children in school buses, emissions comparisons for various school bus models, and sample letters for advocacy purposes. Contains 146 end notes. (KB)

Dating values are salient issues with regard to interpersonal relationships. They provide the basis for the relationship between two people that may help determine how the family will ultimately function. This study is a preliminary analysis that attempted to describe how dating preferences of African-Americans differ with respect to gender and with respect to traditional and non-traditional trait characterizations. African-American male (N=22) and African-American female (N=43) college students completed a questionnaire which assessed four dating preferences. A one-way MANOVA procedure found a gender effect with some associations to traditional standards. Many gender differences were found. Women were more likely to indicate the importance of earning potential than were men and women were more likely than men to believe that the mutual sharing of household duties is important; both of these choices fall into the traditional pattern. However, women were more likely than men to give importance to the non-traditional trait of sensitivity, while the difference for attractiveness was not significant. Overall, the findings from this preliminary study were not consistent with traditional standards. Thus, this research agreed with the literature suggesting that African-Americans have different dating preferences than does the general population. (ABL)

Mexico has been described as a collectivist country, a culture in which its members perceive themselves as part of a group, value interdependence, and derive their identities from the group. This study examined collectivism among Mexican college students (N=79) at two universities. Subjects completed the Individualism-Collectivism Scale. The subscales were labeled as Spouse, Kin, Friend, Parent, Coworker/Classmate, and Neighbor. Scores were most collectivist on Parent and Kin subscales. Women scored as more collectivist on the Parent subscale than did men. Students' scores also differed according to university attended. Those attending a university which charged moderate tuition scored as more collectivist on the Parent and Spouse subscales than those attending a university which charged higher tuition, thus attracting students from wealthier backgrounds. There was also an interaction between gender and university attended with women attending the middle socioeconomic university scoring as most collectivist. These findings support a previous finding that links an emphasis on family relations with collectivism. (Author/ABL)

For nearly two decades, NASA Glenn Research Center has been supporting the development of radioisotope power systems (RPS). NASA desires higher conversion efficiency RPS options that are reliable and robust with long-life design. Dynamic conversion, such as Stirling and Brayton, offer the potential for higher conversion efficiencies than current RPS but have yet to be demonstrated in a flight application. The RPS program sent out a solicitation to investigate options for dynamic conversion technologies. As a result of this solicitation, four dynamic power convertor (DPC) technologies were selected for design and three are proceeding to the fabrication phase of prototype dynamic convertors. One lesson learned from the Advanced Stirling Radioisotope Generator (ASRG) project is that controller development should be coordinated with the development of a dynamic convertor. As a result of this, Glenn has been utilizing hardware from past Stirling convertor projects, including that of the ASRG, to support controller development for the DPCs. Glenn has developed a strong knowledge base on both analog and digital Stirling DPC controllers and will continue to expand and apply that knowledge to the DPCs. Over the past 15 years, controllers were developed at Glenn, at Lockheed Martin (LM), and by the Johns Hopkins University Applied Physics Laboratory (APL). Various generations of the controllers have been developed as lessons were learned through various component- and system-level tests. Some of the tests performed were fault tolerance, flight acceptance vibration, electromagnetic interference (EMI), spacecraft integration, and extended operation. The fault tolerance test characterized the controller’s ability to handle various fault conditions, including high or low bus power consumption, total open load or short circuit, and replacing a failed controller card while the backup maintains control of the Stirling convertor. The vibration test confirms the controller’s ability to control an Advanced Stirling Convertor (ASC) during launch. The EMI test characterized the alternating-current (AC) and direct-current (DC) magnetic and electric fields emitted by the single ASC and if the controller has an impact on the radiated EMI. Spacecraft integration testing in the Radioisotope Power Systems (RPS), System Integration Laboratory (RSIL) provided insight into the electrical interactions between the representative RPS, its associated control schemes, and realistic electric system loads. The extended operation test allows data to be collected over a period of thousands of hours to obtain long-term performance data of the system. This paper describes the history of controller development at Glenn, tests performed on these controllers, and lessons learned.

Future NASA missions could include long-duration flyby, orbital, lander, or rover applications where generating power from sunlight may be limited. Radioisotope power systems (RPSs) provide a dependable power source for missions where inadequate sunlight or operational requirements make other power systems impractical. Over the past 16 years, NASA Glenn Research Center has been supporting the development of RPSs. The advanced Stirling radioisotope generator (ASRG) utilized a pair of advanced Stirling convertors (ASCs). Although flight development of the ASRG has been canceled, much of the technology and hardware continued development and testing to guide future activities. Specifically, a controller for the convertor(s) is an integral part of a Stirling-based RPS. For the ASRG design, the controller maintains stable operation of the convertors, regulates the alternating current produced by the linear alternator of the convertor, provides a specified direct-current output voltage for the spacecraft, and synchronizes the piston motion of the two convertors to minimize vibration as well as manage and maintain operation with a stable piston amplitude and hot-end temperature. It not only provides power to the spacecraft but also must regulate convertor operation to avoid damage to internal components and maintain safe thermal conditions after fueling. Lockheed Martin Coherent Technologies, Inc., has designed, developed, and tested an ASC control unit engineering development unit (ACU EDU) to support this effort. GRC used the ACU EDU as part of its nonnuclear representation of a RPS that also consists of a Dual advanced Stirling convertor simulator (DASCS), and associated support equipment to perform a test in the Radioisotope Power Systems System Integration Laboratory (RSIL). The RSIL was designed and built with flexibility to evaluate hardware utilizing RPS technology. The RSIL provides insight into the electrical interactions between as many as three radioisotope power generators, associated control strategies, and typical electric system loads. The first phase of testing included a DASCS that was developed by Johns Hopkins University Applied Physics Laboratory and simulates the operation and electrical behavior of a pair of ASCs in real time via a combination of hardware and software. Testing included the following spacecraft electrical energy storage configurations: capacitor, battery, and supercapacitor. Testing of the DASCS and ACU in each energy storage configuration included simulation of a typical mission profile and transient voltage and current data during load turnon and turnoff. Testing for these devices also included the initiation of several system faults such as short circuits, electrical bus overvoltage, undervoltage, and a "dead bus" recovery to restore normal power operations. The goal of this testing was to verify operation of the ACU(s) when connected to a spacecraft electrical bus. The results of these tests are presented here.