Preservice teachers’ use of contrasting cases in mathematics instruction

Drawing comparisons between students’ alternative solution strategies to a single mathematics problem is a powerful yet challenging instructional practice. We examined 80 preservice teachers’ when asked to design a short lesson when given a problem and two student solutions—one correct and one incorrect. These micro-teaching events were videotaped and coded, revealing that fewer than half of participants (43%) made any explicit comparison or contrasts between the two solution strategies. Those who did were still not likely to use additional support strategies to draw students’ attention to key elements of the comparison. Further, correlations suggest that participants’ mathematical content knowledge may be related to whether participants’ showed contrasting cases but not to whether they used specific pedagogical cues to support those comparisons. While these micro-teaching events differ from the interactive constraints of a classroom, they reveal that participants did not immediately orient toward differing student solutions as a discussion opportunity, and that future instruction on contrasting cases must highlight the utility of this practice.     

„Jeder Schule ihre Lehrer“?

Neue Personalauswahl- und Einstellungsverfahren, an denen die Einzelschulen ma?geblich beteiligt werden, kommen bei der Besetzung von Lehrerstellen in zahlreichen Bundesl?ndern seit Mitte der 1990er-Jahre zur Anwendung und haben mittlerweile die herk?mmlichen zentralen Auswahl- und Zuweisungsverfahren zumindest in einigen von ihnen nahezu vollst?ndig abgel?st. Die Praxis und Wirkung der neuen Auswahlverfahren wurde bislang allerdings nicht systematisch untersucht. In diesem Beitrag werden empirische Befunde einer Untersuchung von Schulen in Nordrhein-Westfalen vorgestellt, die im Jahr 2002 freie Lehrerstellen über das neue Ausschreibungsverfahren besetzt haben. Erfasst wurden unter anderem die in der Praxis angewandten Kriterien der Personalauswahl und die Inhalte der Auswahlgespr?che, die Beurteilung des neuen Auswahl- und Einstellungsverfahrens durch die beteiligten Schulleitungen und Mitglieder der Auswahlkommissionen, Einsch?tzungen und Erfahrungen der neu eingestellten Lehrkr?fte sowie der Verlauf ihrer Berufseinstiegsphase und ihre Bew?hrung am neuen Arbeitsplatz.     

Photoresists for microlithography

Photoresist technology, which is used for micro-patterning exploits changes in properties of polymeric materials, such as their solubility or volatility, upon photo-irradiation. This process has greatly benefitted from the knowledge base of organic chemistry and photo-induced organic transformations. The role of chemistry in the development of photoresists is described in this article.     

Genetics Literacy: Insights From Science Teachers’ Knowledge,Attitude, and Teaching Perceptions

Teachers have a crucial role to play in raising future generations of citizens who are aware of issues in genetics literacy such as gene therapy, cloning, and stem cell research. Teachers’ teaching practices are influenced by their knowledge in genetics literacy and their attitudes towards different issues. Accordingly, this study explored the relationships among middle school science teachers’ background characteristics (gender, teaching experience, self-perceived interest in and self-perceived knowledge of genetics), their genetics literacy levels, their attitudes towards various issues in genetics literacy, and their perceptions of teaching issues in genetics literacy. Data were collected from 435 Turkish middle school science teachers by completing the Genetics Literacy Assessment Inventory, the scale for attitudes towards issues in genetics literacy and perceptions of teaching issues in genetics literacy. The results of canonical correlation analysis suggested that being female, having a high level of interest in genetics, and perceiving oneself as knowledgeable in genetics were associated with higher levels of knowledge in genetics literacy and holding favorable general attitudes. These teachers believed in the necessity of introducing genetics literacy and held higher self-efficacy teaching beliefs regarding the teaching of issues in genetics literacy in their classes. However, they tended to emphasize more impeding factors as well as hold unfavorable attitudes towards gene therapy and gene therapy applications, implying that their attitudes were context dependent.     

Complementary feeding patterns among ethnic groups in rural western China

Objective

This study investigated complementary feeding practices among four ethnic groups (Han, Uygur, Tibetan, and Zhuang) based on a cross-sectional survey in rural western China.

Methods

In 2005, a stratified multistage cluster random sampling method was used to recruit 9712 children (7411 Han, 1032 Uygur, 678 Tibetan, and 591 Zhuang) between 6 and 35 months of age and their mothers from 45 counties in 10 provinces (autonomous regions, municipalities) in western China.

Results

The rates of early introduction (before 6 months) of complementary foods in four ethnic groups (Han, Uygur, Tibetan, and Zhuang) were 71.30%, 95.95%, 82.40%, and 72.30%, respectively. The Infant and Child Feeding Index (ICFI) for Uygur and Tibetan children was lower than that for Han children at all age groups. Uygur children were more likely to have unqualified ICFI compared with Han children in a multivariate logistic regression (odds ratio (OR)=5.138, 95% confidence interval (CI): 4.340–6.084). A higher level of maternal education, greater family wealth, and the availability of complementary feeding educational materials decreased the likelihood of an unqualified ICFI. The nutritional status of children (Han, Tibetan, and Zhuang) with qualified ICFI was better than that for children with unqualified ICFI.

Conclusions

Appropriate interventions are required to improve complementary feeding practices in rural western China.

     

Adjunctive drinking during variable and random-interval food reinforcement schedules

Rats were trained to leverpress for food and subsequently exposed to either arithmetic series or random variable-interval reinforcement schedules. Adjunctive drinking developed in all subjects exposed to arithmetic variable-interval reinforcement, but did not develop in six of the eight animals trained on the random schedule. The results suggest that adjunctive drinking is the result of an interaction between the tendency of rats to drink after eating and the ability of locally low probabilities of reinforcement within schedules to induce conditioned behavioral states.     

Practicum Placement in a Counseling-Employment Agency for Disadvantaged Youth

In order to emphasize the development of skills in helping the culturally disadvantaged, graduate students were given practicum placement in a Department of Labor-financed agency which gave counseling and employment training to disadvantaged youth. Students attended staff meetings, interviewed staff members concerning the work they performed, and discussed client contacts with caseworkers, in addition to interviewing agency clients. Increased awareness of problems, broadened conceptualizations, and expansion of interpersonal skills were seen as advantages of the practicum. Limitations included some lack of goal clarity and inefficiency of time use in dealing with this clientele.