Le problème de l'enseignement des mesures des grandeurs géométriques à partir de l'exemple des aires

Nous tentons dans cet article à la fois d'élucider un certain nombre de points théoriques concernant la mesure de ces grandeurs et de proposer quelques réflexions didactiques aussi bien sur les difficultés que doivent surmonter les élèves que sur les problèmes qu'on veut les amener à pouvoir résoudre. Nous avons plus particulièrement étudié le problème de la mesure des aires, c'est pourquoi notre réflexion sera plus approfondie dans ce cas que dans celui des volumes

Numerical radiative transfer with state-of-the-art iterative methods made easy

This article presents an on-line tool (rttools.irap.omp.eu) and its accompanying software ressources for the numerical solution of basic radiation transfer out of local thermodynamic equilibrium (LTE). State-of-the-art stationary iterative methods such as Accelerated $\Lambda$-Iteration and Gauss-Seidel schemes, using a short characteristics-based formal solver are used. We also comment on typical numerical experiments associated to the basic non-LTE radiation problem. These ressources are intended for the largest use and benefit, in support to more classical radiation transfer lectures usually given at the Master level.Comment: 8 pages, 5 figures, accepted for Eur. J. Phys. - see also (and use!) http://rttools.irap.omp.e

Analisis Sebaran Kebisingan Akibat Aktivitas Landing dan Take-Off Menggunakan Software Integrated Noise Model 7.0d di Sekitar Bandar Udara Ahmad Yani Semarang

Kegiatan operasional di bandara seperti aktivitas landing dan take-off menimbulkan kebisingan. Tingkat kebisingan yang tinggi dapat mengganggu kesehatan manusia secara signifikan apabila manusia terpapar kebisingan dalam periode waktu yang lama dan terus-menerus. Oleh karena itu, informasi tingkat kebisingan dibutuhkan untuk menentukan sebaran kebisingan. Sebaran kebisingan di sekitar bandara dapat diperkirakan dan dievaluasi dengan menggunakan software Integrated Noise Model (INM). Simulasi kontur kebisingan pada penelitian ini menggunakan data penerbangan selama 1 minggu dengan 333 kedatangan dan 334 keberangkatan. Indeks Weighted Equivalent Continuous Percieved Noise Level (WECPNL) dari hasil simulasi divalidasi dengan hasil pengukuran yang dilakukan di sekitar bandara. Berdasarkan penelitian, total kawasan kebisingan Bandara Ahmad Yani adalah 6,949 km2 dengan berjarak 0,987 km dari runway 31 ke arah Kota Semarang, 4,852 km dari runway 13 ke arah laut dan 0,438 km dari sisi runway. Terdapat 7 sekolah dan 1 rumah sakit yang berada dalam kawasan kebisingan tingkat I dan 0,01 km2 permukiman yang berada di kawasan kebisingan tingkat II. Oleh karena itu, 3 skenario pengendalian disimulasikan yaitu (1) reschedule jadwal penerbangan; (2) pengaturan arah landing and take-off; (3) gabungan skenario 1 dan 2. Berdasarkan penelitian, skenario ketiga merupakan skenario yang paling efektif mengurangi dampak kebisingan karena 37,602% kawasan kebisingan base case dapat direduksi. Terlebih lagi, tidak ada lokasi sensitif seperti rumah sakit, sekolah dan permukiman yang berada dalam kawasan kebisingan ini

Recruiting Small Manufacturing Worksites That Employ Multiethnic, Low-Wage Workforces Into a Cancer Prevention Research Trial

Introduction: Worksites, including those that employ multiethnic, low-wage workforces, represent a strategic venue for reaching populations at risk for developing cancer. Methods: We surveyed 197 small manufacturing worksites prior to an effort to recruit their workforces into a randomized clinical trial designed to test the effectiveness of a cancer prevention intervention among multiethnic, low-wage manufacturing workers. This paper assesses the external validity of the trial based on three factors: the percentage of potential trial sites excluded from consideration, the percentage of eligible worksites that adopted the trial, and worksite characteristics associated with adoption. Results: We found no statistically significant differences between worksites that adopted the trial and worksites that declined the trial with regard to employee demographics, anticipated changes in workforce size, and perceived importance and history of offering health promotion and occupational health and safety activities. Conclusion: Small manufacturing worksites present a viable venue for reaching multiethnic, low-wage populations with cancer prevention programs, although program adoption rates may be low in this sector. Worksites that adopted the trial are likely to represent worksites deemed eligible for the trial

Norms and their relationship to behavior in worksite settings : an application of the Jackson Return Potential Model

To measure health norms and assess their influence on behavior among 2541 employees in 16 manufacturing worksites using an adapted Jackson\u27s Return Potential Model (RPM). METHODS: Worksite-level norm intensity, crystallization, and normative power were calculated for several behaviors; linear regression analyses tested whether normative power was related to each health behavior. RESULTS: Norms about safe work practices and smoking were most intense; norms about safe work practices were most crystallized. Safe work practices and smoking held the highest normative power; healthy eating held the least normative power. Comparing norm characteristics across health behaviors leads to important leverage points for intervening to influence norms and improve worker health

Biomarker Validation of Dietary Intervention in Two Multiethnic Populations

Introduction: Intervention studies have been designed to change dietary and lifestyle factors associated with chronic diseases, but self-reported behavior change may incorporate intervention-related bias. This study examines plasma nutrient concentration and correlations with self-reports in the Healthy Directions intervention study. The Healthy Directions intervention studies were designed to increase multivitamin use, fruit and vegetable consumption, and physical activity in working-class, multiethnic populations. Methods: Participants in both studies completed interviewer-administered questionnaires that collected information on sociodemographic and health behavior characteristics. Postintervention blood samples were collected from 209 participants and pooled in pairs within study and within intervention group. Results: We found significantly higher plasma concentrations of retinol (P = .01) and α-carotene (P = .03) in the intervention than in the usual care group. Self-reported multivitamin users had significantly higher concentrations of retinol (P < .001), β-carotene (P = .02), and α-tocopherol (P < .001). Those who reported four or more fruit and vegetable servings per day had higher lutein and zeaxanthin (P = .05) and β-cryptoxanthin (P = .05) concentrations than those consuming fewer. Plasma nutrient concentrations were associated with reported multivitamin use and fruit and vegetable intake, but the correlations were generally higher in the usual care group. Conclusion: We found significant postintervention differences in plasma carotenoid and tocopherol concentrations by treatment group, multivitamin use, and fruit and vegetable intake. However, because we only obtained postintervention blood samples, we were unable to assess preintervention-to-postintervention changes in plasma nutrients. Self-reported intakes were significantly correlated with plasma nutrient concentrations, but the strength of the correlations differed by group, suggesting some intervention-related bias in the questionnaire responses

Emergences and affordances as opportunities to develop teachers’ mathematical content knowledge

Teachers’ mathematical content knowledge has been under scrutiny for some time. This development is in the wake of learners’ unsatisfactory performance in national examinations and international achievement tests. A widely held belief is that one, if not the most important, of the efforts to improve and enhance the performance and achievement in mathematics of learners is addressing teachers’ mathematical content and pedagogical content knowledge through continuous professional development initiatives. The focus of this article is on the former. It describes how emergent and affording opportunities are brought to the fore from classroom observations and interactions in workshops and institutes with practising teachers. It concludes that this in situ dealing with mathematical content knowledge holds much promise for buy-in by teachers because it addresses an immediate need related to their practice

The inverse hazard law: Blood pressure, sexual harassment, racial discrimination, workplace abuse and occupational exposures in US low-income black, white and Latino workers

http://dx.doi.org/10.1016/j.socscimed.2008.09.03

Methods and Baseline Characteristics of Two Group-Randomized Trials With Multiracial and Multiethnic Working-class Samples

Introduction: Few papers address the methodological challenges in recruiting participants for studies of cancer prevention interventions designed for multiracial and multiethnic working-class populations. This paper reports the results of the sample selection and survey methods for two group-randomized intervention studies. Methods: The two group-randomized intervention studies, Healthy Directions–Small Business (HD–SB) and Healthy Directions–Health Centers (HD–HC), included a worksite-based study in 26 small manufacturing businesses and a study in 10 outpatient health centers. We used selection and recruitment methods to obtain a multiracial and multiethnic working-class study sample. In 2000 and 2001, we assessed baseline measures of sociodemographic characteristics and behavioral outcomes by self-report. We then computed intraclass correlation coefficients (ICCs). Results: Of the 1740 participants in the HD–SB study, 68% were non-Hispanic whites, and 76% had working-class occupations. In the HD–HC study, 59% of 2219 participants were non-Hispanic whites. Among those who worked, 51% had working-class occupations. Large percentages of both samples reported not meeting recommended guidelines for the target behaviors. For example, 86% of members of both samples consumed fewer than the recommended five servings of fruits and vegetables per day. The ICCs for the four target behaviors in HD–SB were between 0.006 and 0.02. In the HD–HC study, the ICCs ranged from 0.0004 to 0.003. Conclusion: The two studies were successful in recruiting multiracial and multiethnic working-class participants. Researchers will find the estimates of the primary outcomes and their ICCs useful for planning future studies