Properties of In-Doped ZnO Films Grown by Metalorganic Chemical Vapor Deposition on GaN(0001) Templates

We investigated the properties of indium-doped zinc oxide layers grown by metalorganic chemical vapor deposition on semi-insulating GaN(0001) templates. Specular and transparent films were grown with n-type carrier concentrations up to 1.82 × 10¹⁹ cm⁻³ as determined by Hall measurements, and all In-doped films had carrier concentrations significantly higher than that of a comparable undoped film. For low In flows, the carrier concentration increased accordingly with trimethyl-indium (TMIn) flow until a maximum carrier concentration of 1.82 × 10¹⁹ cm⁻³ was realized. For higher In flows, the carrier concentration decreased with increasing TMIn flow rate. Sheet resistance as low as 185 Ω/sq was achieved for the In-doped films, which is a significant decrease from that of a comparable undoped ZnO film. Our n-type doping studies show that In is an effective dopant for controlling the n-type conductivity of ZnO.     

Educational approaches to teaching introductory courses

Conclusions One key thread ran throughout the symposium—hands-on learning. In a panel discussion featuring Ambrose, Bondaryk, Bardes, and McMahon, all agreed that the biggest lack in students’ knowledge is a lack of practical application, a “lack of tinkering.” One way to develop hands-on learning is through homework; as Ambrose commented, “practice makes experts.” Tapping into everyday life is a good way of making class interesting, the panel agreed. Using examples from the news or from students’ lives will enable them to make the necessary connections to take what they learn and apply it. Regardless of the methods used to teach, the panel concluded that drastic change will not work. Evaluate the students and the classroom and ease into changes; do not alienate the students. After all, if the students do not come, they cannot learn. Tammy M. Beazley is copy editor of JOM Editor’s Note: A hypertext-enhanced version of this article can be found on the TMS web site at ww.tms.org/pubs/journals/JOM/9805/Beazley-9805.html. Also, three papers from the symposium reviewed here comprise the April installment of JOM-e. Abstracts and URL addresses can be found on page 2.     

Mediated Perceptions: Contributions of Phenomenological Film Theory to Understanding the Interactive Video Experience

This article examines the spatial relationships between avatars (i.e., graphical identities or icons) over time in a 2-dimensional online chat environment. The Spatial Distance Analysis Program (SDAP) was developed to measure the distance between avatars in a specially designed Palace environment. Correlations between distance and interpersonal communication constructs of (1) conversational appropriateness, (2) social attraction, and (3) uncertainty reduction indicate that distance effects are significant in an online environment. Specifically, it was found that general conversational appropriateness mediated between uncertainty reduction and specific conversational appropriateness for individuals who moved closer together and farther apart over time, respectively. Furthermore, the relationship between social attraction and distance indicated a significant positive parabolic function; that social attraction (i.e., liking) decreased at middle distances and increased at low and high distances. This finding suggests that there are three interpersonal distance zones in online communication.     

Gender differences in self-concept among children and adolescents: A meta-analysis of multidimensional studies.

This investigation consolidated the recent research on gender differences in self-concept among children and youth by conducting a systematic meta-analysis of research published since 1980, particularly involving self-concept as a multidimensional phenomenon. Through a comprehensive search process, 22 studies representing over 19,000 child and adolescent participants were analyzed. The articles included participant samples from 7 nations: the US, Australia, Northern Ireland, South Africa, Finland, Norway, and Canada. Participants ranged from 1st grade through 12th grade. Mean effect size estimates across dimensions showed a complex pattern of gender differences and similarities, some of which were consistent across grade levels and others of which were not. Although some of the findings defied stereotypes, several were consistent with previous notions regarding differences in self-concept based on gender. The direction and complexity of these results emphasizes the importance of discussing developmental differences in self-concept in a thoughtful and careful manner and argues against the use of simplistic global generalizations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Students’ perceptions about the use of video games in the classroom

Video games are often regarded as promising teaching and learning tools for the 21st century. One of the main arguments is that video games are appealing to contemporary students. However, there are indications that video game acceptance cannot be taken for granted. In this study, a path model to examine and predict student acceptance of video games is proposed, and empirically tested by involving 858 secondary school students. The results show that students’ preference for using video games in the classroom is affected directly by a number of factors: the perceptions of students regarding the usefulness, ease of use, learning opportunities, and personal experience with video games in general. Gender effects are found as well, but appear to be mediated by experience and ease of use.     

The importance of callous–unemotional traits for extending the concept of psychopathy to children.

This study focused on the use of callous–unemotional (CU) traits to identify a subgroup of children with both attention deficit/hyperactivity disorder (ADHD) and a conduct problem diagnosis (oppositional defiant disorder [ODD] or conduct disorder [CD]) who show characteristics similar to adults with psychopathy. In a clinic-referred sample of children aged 6 to 13 years (N?=?154), those with diagnoses of both ADHD and ODD/CD were divided on the basis of teacher ratings of CU traits. Children high on these traits showed features typically associated with psychopathy, such as a lack of fearfulness and a reward-dominant response style. Furthermore, children with CU traits seemed less distressed by their behavior problems. These findings are consistent with research on adults showing that impulsivity and antisocial behavior alone are insufficient to document persons who fit the construct of psychopathy. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

From beyond to within their grasp: The rudiments of analogical problem solving in 10- and 13-month-olds.

Four experiments were conducted to assess infants' ability to solve isomorphic problems and to explore the nature of early representations. Ten- and 13-month-olds attempted to solve problems that required combining 2 subgoals to bring a toy (goal object) within reach. A problem-series paradigm was used in which 3 tasks differing in surface features but sharing common goal structures and similar solutions were presented. The results indicate that 13-month-olds transferred a modeled solution strategy across isomorphic problems, whereas 10-month-olds did so only after experiencing either multiple source problems or high perceptual similarity between problems. Comprehension of the relations between solution actions and outcome, and between tools and target object, appeared critical to transfer. The results suggest that 1-year-olds can construct relatively abstract and flexible mental representations and that analogical problem solving may be 1 of the major accomplishments during the 1st year of life. (PsycINFO Database Record (c) 2010 APA, all rights reserved)