Laplacian modes probing gauge fields

We show that low-lying eigenmodes of the Laplace operator are suitable to represent properties of the underlying SU(2) lattice configurations. We study this for the case of finite temperature background fields, yet in the confinement phase. For calorons as classical solutions put on the lattice, the lowest mode localizes one of the constituent monopoles by a maximum and the other one by a minimum, respectively. We introduce adjustable phase boundary conditions in the time direction, under which the role of the monopoles in the mode localization is interchanged. Similar hopping phenomena are observed for thermalized configurations. We also investigate periodic and antiperiodic modes of the adjoint Laplacian for comparison. In the second part we introduce a new Fourier-like low-pass filter method. It provides link variables by truncating a sum involving the Laplacian eigenmodes. The filter not only reproduces classical structures, but also preserves the confining potential for thermalized ensembles. We give a first characterization of the structures emerging from this procedure.Comment: 43 pages, 26 figure

A Lattice Calculation of the Heavy Quark Universal Form Factor

A computation of the Isgur-Wise universal form factor using a lattice implementation of the heavy quark effective theory is described, and the results of a lattice simulation are presented.Comment: 3 pages in postscrip

Renormalization of the Lattice Heavy Quark Classical Velocity

In the lattice formulation of the Heavy Quark Effective Theory (LHQET), the classical velocity is renormalized. The origin of this renormalization is the reduction of Lorentz (or O(4)) invariance to (hyper)cubic invariance. The renormalization is finite and depends on the form of the decretization of the reduced heavy quark Dirac equation. For the Forward Time - Centered Space discretization, the renormalization is computed both perturbatively, to one loop, and non-perturbatively using an ensemble of lattices provided by the Fermilab lattice collaboration. The estimates of the leading (linear) shift agree, and indicate that for small classical velocities, the renormalized velocity is reduced by about 25-30% relative to its bare (input) value.Comment: 4 pages in uuencoded compressed postscript (using uufiles); Talk given at Lattice '95 (Melbourne

Bilingual Teaching in German Geography Classrooms. Reflections on the Development of Linguistic, Scientific, and Intercultural Competencies

Obwohl in Deutschland seit über 40 Jahren bilingualer Unterricht erteilt wird, sind die empirischen Untersuchungen zu seiner Lernwirksamkeit zumeist jüngeren Datums. Der vorliegende Artikel stellt die aus Sicht der Verfasser wichtigsten Untersuchungen vor und diskutiert sie kritisch. Während die Ergebnisse hinsichtlich des Fremdsprachen-Kompetenzzuwachses durch bilingualen Unterricht als weitgehend gesichert gelten, liegen zum fachlich-geographischen Kompetenzzuwachs nach wie vor keine eindeutigen Erkenntnisse vor. Unterschiedlich fällt auch die Beantwortung der Frage aus, ob der bilinguale Geographieunterricht ein besonderes Potential für den Erwerb interkultureller Kompetenzen bietet. Neben der kritischen Analyse empirischer Untersuchungen skizzieren wir in diesem Beitrag ein Kompetenzmodell für den bilingualen Geographieunterricht, das den Belangen der Geographie stärker Rechnung tragen soll. Trotz der vielen offenen Fragen plädieren wir für ein starkes Engagement unseres Faches in der Diskussion zum bilingualen Unterricht, denn aus ureigenem Interesse der Geographie sprechen eine Reihe von Gründen für eine besondere Berücksichtigung dieser Unterrichtsform. Vermittlung von zeitgemäßer raumbezogener Handlungskompetenz erfordert heute einen multiperspektivischen Zugang auch mittels fremdsprachiger Quellen und Personen.Bilingual teaching in Germany refers to an immersion-like teaching approach in usually two or three non-linguistic subjetcs like Geography. In the meantime it looks back on a tradition of several decades. Yet it has only been in recent years that empirical research actually started to address the basic questions: What are the costs and what are the benefits of this approach? The article provides an overview and a critical discussion of the relevant empirical research. While the benefits for the learners‘ language competences are well proven, those for the Geography competences are still unclear. If Geography is to remain the predominant bilingually taught content subject, this needs to be clarified. It has also not yet been possible to decide whether bilingual teaching has a special potential to foster intercultural competences. We argue that existing studies have not sufficiently dealt with this question. Along with these reflections on learners‘ competences, we as Geographers also have to take the growing internationalization of our profession and the increasing importance of cross-border communication into consideration. By supporting bilingual teaching we provide a basis for an international geographical understanding in both education and society, and we also broaden future young academics’ perspectives

Genes in the postgenomic era

We outline three very different concepts of the gene - 'instrumental', 'nominal', and 'postgenomic'. The instrumental gene has a critical role in the construction and interpretation of experiments in which the relationship between genotype and phenotype is explored via hybridization between organisms or directly between nucleic acid molecules. It also plays an important theoretical role in the foundations of disciplines such as quantitative genetics and population genetics. The nominal gene is a critical practical tool, allowing stable communication between bioscientists in a wide range of fields grounded in well-defined sequences of nucleotides, but this concept does not embody major theoretical insights into genome structure or function. The post-genomic gene embodies the continuing project of understanding how genome structure supports genome function, but with a deflationary picture of the gene as a structural unit. This final concept of the gene poses a significant challenge to conventional assumptions about the relationship between genome structure and function, and between genotype and phenotype