Fine Grid Asteroseismology Of G117-B15A And R548

We now have a good measurement of the cooling rate of G117-B15A. In the near future, we will have equally well determined cooling rates for other pulsating white dwarfs, including R548. The ability to measure their cooling rates offers us a unique way to study weakly interacting particles that would contribute to their cooling. Working toward that goal, we perform a careful asteroseismological analysis of G117-B15A and R548. We study them side by side because they have similar observed properties. We carry out a systematic, fine grid search for best-fit models to the observed period spectra of those stars. We freely vary four parameters: the effective temperature, the stellar mass, the helium layer mass, and the hydrogen layer mass. We identify and quantify a number of uncertainties associated with our models. Based on the results of that analysis and fits to the periods observed in R548 and G117-B15A, we clearly define the regions of the four-dimensional parameter space occupied by the best-fit models.NSF AST 05-07639Astronom

The mixed glass former effect in 0.5Na2S + 0.5[xGeS2 + (1-x)PS5/2] glasses

The rapidly growing global energy demand, especially for energy from renewable sources, requires development of longer-lasting, safer, and smaller batteries. Ion-conducting glasses are of particular interest as candidates for solid electrolyte materials in next-generation batteries. Commercial solid-state electrolytes require an ionic conductivity of at least 10-3 S/cm. In order to meet this design constraint, development of new ion-conducting glasses is required. An increase or decrease in the ionic conductivity of glasses can be achieved by mixing two glass former cations at constant fraction of the mobile cation, known as the mixed glass former effect (MGFE). This enhancement or depression of the ionic conductivity is non-linear and non-additive, and its cause is currently unknown. The 0.5Na2S + 0.5[xGeS2 + (1-x)PS5/2] glasses exhibit a negative MGFE in Na+ ion conductivity. If the cause of this depression in the Na+ ion conductivity is better understood, it may enable the design of mixed glass former systems that will exhibit enhancement of the ionic conductivity. We hypothesis that changes in short range order structures occur when the thio-phosphate and thio-germanate glass networks are mixed, causing the negative MGFE. Our comprehensive study of the glass structure and physical properties of the 0.5Na2S + 0.5[xGeS2 + (1-x)PS5/2] glasses shows that structural changes in the ternary glasses strongly correlate with the decrease in the ionic conductivity

Метод организации системы поисковой рекламы в сети Интернет

Предлагается метод организации системы поисковой рекламы, основанный на теории нечетких множеств, для выбора рекламных объявлений сайтов, релевантных поисковому запросу пользователя, при соблюдении ограничений рекламодателя

E-Learning in family medicine education : faculty support in a community clerkship ; an evaluation

E-Learning soll im Rahmen der allgemeinmedizinischen Ausbildung von Medizinstudierenden erprobt werden. Ein zielgruppenspezifisches, multimodulares Online-Angebot begleitet Medizinstudenten des 10. Semesters während ihres dezentralen Praktikums in hausärztlichen Praxen. Folgende Lehrziele werden angestrebt: (1) Einführung in das E-Learning, (2) Klinische Allgemeinmedizin - Online-Modul, (3) Chronic Care Online-Modul, (4) Online-Bewerbung. Die systematische Evaluation zeigt, dass E-Learning die Kommunikation der Studierenden untereinander und mit der universitären Lehreinheit während des Praktikum fördert. Auf der Grundlage der in diesem Pilotversuch gewonnenen Erfahrungen erscheint die Kombination mit Präsenzunterricht (Blended Learning) eine vielversprechende Option für die allgemeinmedizinische Ausbildung zu sein.E-learning was planned as a test for medical students within their curriculum of family medicine. A multi-modular onlineoffer specific to the target group accompanies the 10th term medical students during their peripheral practical courses in family practices. Teaching objectives are as follows: (1) Introduction into e-learning, (2) clinical general medicine - onlinemodule, (3) chronic care online-module, (4) online-application. The systematic evaluation shows that e-learning promotes the communication of students both among themselves and with the university during their practical courses. On the basis of the experiences from this pilot test the combination with blended learning seems to be a promising option for medical education

Basin structure of optimization based state and parameter estimation

Most data based state and parameter estimation methods require suitable initial values or guesses to achieve convergence to the desired solution, which typically is a global minimum of some cost function. Unfortunately, however, other stable solutions (e.g., local minima) may exist and provide suboptimal or even wrong estimates. Here we demonstrate for a 9-dimensional Lorenz-96 model how to characterize the basin size of the global minimum when applying some particular optimization based estimation algorithm. We compare three different strategies for generating suitable initial guesses and we investigate the dependence of the solution on the given trajectory segment (underlying the measured time series). To address the question of how many state variables have to be measured for optimal performance, different types of multivariate time series are considered consisting of 1, 2, or 3 variables. Based on these time series the local observability of state variables and parameters of the Lorenz-96 model is investigated and confirmed using delay coordinates. This result is in good agreement with the observation that correct state and parameter estimation results are obtained if the optimization algorithm is initialized with initial guesses close to the true solution. In contrast, initialization with other exact solutions of the model equations (different from the true solution used to generate the time series) typically fails, i.e. the optimization procedure ends up in local minima different from the true solution. Initialization using random values in a box around the attractor exhibits success rates depending on the number of observables and the available time series (trajectory segment).Comment: 15 pages, 2 figure

More students with migration backgrounds at Universities of Teacher Education. Theoretical reflections and empirical insights on potential aspects and challenges from the perspectives of pre-service teachers and lecturers

Continuous migration processes are shaping the social reality in Switzerland and their education system, thus also the Universities of Teacher Education. However, the growing migration-related diversity in the student-population is not reflected among pre- and in-service teachers, since to date only few successful young adults with migration backgrounds decide to become teachers. While the migration-related diversity of the student-population in schools has been receiving a lot of attention for some time, up to date there are still hardly any meaningful studies about pre-service teachers with migration backgrounds in Switzerland. Due to the lack of empirical data so far, it can only be speculated what the potential aspects and challenges could be if the percentage of students with migration backgrounds at Universities of Teacher Education were to increase. In this context the research project DIVAL (= Diversity of pre-service teachers: focus migration / Diversität angehender Lehrkräfte: Fokus Migration) was conducted at the University of Teacher Education St.Gallen. It consists of two sub-studies: Based on an online survey the migration-related diversity of all students was assessed. During focused group discussions, students with and without migration backgrounds as well as lecturers where asked about the relevance they attribute to migration backgrounds during teacher education. (DIPF/Orig.)

Developing Non‑Residential Building Stock Archetypes For LCI—A German Case Study Of Office And Administration Buildings

To accomplish the national and international climate goals, building renovation and optimisation of their energy and resource efficiency are essential. Thus, reliable information on the building stock (BS) is necessary. Most previous building typologies are focussing on residential buildings and the operational phase. This paper shows the development of a methodology for generating non-residential building (NRB) typologies for life cycle inventory analysis (LCI) of building constructions. Hereby, archetypes of office, administration and department (OAD) buildings are developed, exemplarily for the German NRB stock