Quantum Fields as Operator Valued Distributions and Causality

Quantum Field Theory with fields as Operator Valued Distributions with adequate test functions, -the basis of Epstein-Glaser approach known now as Causal Perturbation Theory-, is recalled. Its recent revival is due to new developments in understanding its renormalization structure, which was a major and somehow fatal disease to its widespread use in the seventies. In keeping with the usual way of definition of integrals of differential forms, fields are defined through integrals over the whole manifold, which are given an atlas-independent meaning with the help of the partition of unity. Using such partition of unity test functions turns out to be the key to the fulfilment of the Poincar\'e commutator algebra as well as to provide a direct Lorentz invariant scheme to the Epstein-Glaser extension procedure of singular distributions. These test functions also simplify the analysis of QFT behaviour both in the UV and IR domains, leaving only a finite renormalization at a point related to the arbitrary scale present in the test functions. Some well known UV and IR cases are examplified. Finally the possible implementation of Epstein-Glaser approach in light-front field theory is discussed, focussing on the intrinsic non-pertubative character of the initial light-cone interaction Hamiltonian and on the expected benefits of a divergence-free procedure with only finite RG-analysis on physical observables in the end.Comment: 20 pages,2 figure

QED Fermi-Fields as Operator Valued Distributions and Anomalies

The treatment of fields as operator valued distributions (OPVD) is recalled with the emphasis on the importance of causality following the work of Epstein and Glaser. Gauge invariant theories demand the extension of the usual translation operation on OPVD, thereby leading to a generalized $QED$ formulation. At D=2 the solvability of the Schwinger model is totally preserved. At D=4 the paracompactness property of the Euclidean manifold permits using test functions which are decomposition of unity and thereby provides a natural justification and extension of the non perturbative heat kernel method (Fujikawa) for abelian anomalies. On the Minkowski manifold the specific role of causality in the restauration of gauge invariance (and mass generation for $QED_{2}$) is examplified in a simple way.Comment: soumis le 22/09/200

Bargaining under Large Risk - An Experimental Analysis -

We present an experimental study to learn about behavior in bargaining situations under large risks. In order to implement realistic risks involved in the field, we calibrate the experimental parameters from an environment involving substantial variation in profits, the motion picture industry. The leading example is the production of a movie that may give rise to a sequel, so actors and producers negotiate sequentially. We analyze the data in light of alternative behavioral approaches to understanding bargaining behavior under large risk.Bargaining, Large Risk, Equity, Experiments, Calibration

Aspects of fine-tuning of the Higgs mass within finite field theories

We reanalyze the perturbative radiative corrections to the Higgs mass within the Standard Model in the light of the Taylor-Lagrange renormalization scheme. This scheme naturally leads to completely finite corrections, depending on an arbitrary scale. The formulation avoids very large individual corrections to the Higgs mass. This illustrates the fact that the so-called fine-tuning problem in the Standard Model is just an artifact of the regularization scheme. It should therefore not lead to any physical interpretation in terms of the energy scale at which new physics should show up, nor in terms of a new symmetry. We analyze the intrinsic physical scales relevant for the description of these radiative corrections.Comment: 9 pages. arXiv admin note: substantial text overlap with arXiv:1011.174

Characterization of a protein of the rodent malarial parasite Plasmodium chabaudi containing a novel leucine-histidine zipper

Clones from cDNA and genomic DNA libraries of Plasmodium chabaudi 96V covering the entire open reading frame for a yet uncharacterized malarial protein were isolated Counting the first ATG as start codon the intronless gene codes for a 229 kDa protein. In the centre of the protein a 364 amino add repeat region is located and is based on 32 11-mer repeats divided by two 6-mer repeats into three blocks.Modelling of the repeat region led us to propose a model where each of the three units forms an a-helical coiled-coil triple-helix containing a novel leucine-histidine zipper. Each unit resembles in structure the units present in spectrin molecules. The repeat region is flanked by predicted heptad based a-helical coiled-coil regions and the 229 kDa protein has an overall character of a cytoskeletal protein.Antisera raised against recombinant polypeptides from two different regions of the 229 kDa protein reacted in western-blotting experiments with a Mr 240 000/ 225 000 doublet present in protein extracts from P. chabaudi 96V. The same sera in immunofluorescence suggested a localization of the 229 kDa protein in the organelles of the apical complex, presumably in the rhoptry organelles, and an assodation of the 229 kDa protein with the erythrocyte membrane. Furthermore it was shown in westernblotting experiments with the recombinant polypqjtides that the 229 kDa protein is a natural immunogen during infection.We named the 229 kDa protein Rq>eated Organellar Protein (ROPE) and suggest that ROPE may be involved in the process of invasion, that it interacts with the erythrocyte cytoskeleton and that the leucine-histidine zipper may be involved in molecular mimicry of spectrin

Experience and knowledge - interpretative patterns and forms of knowledge among professional pedagogues and social workers in out-of-school work with children and adolescents

Auf der Basis von narrativen, biographisch angelegten Interviews wird den berufsorientierten Deutungsmustern, Handlungsplänen und dem fachlichen Wissen von sozialpädagogischen Akteuren nachgespürt, die in Handlungsfeldern der außerschulischen Kinder- und Jugendarbeit tätig sind. Der Ertrag einer qualitativ orientierten empirischen Analyse der beruflichen Habitualisierung von Pädagoginnen und Pädagogen mit den unterschiedlichsten Profilen wird exemplarisch über eine Fallrekonstruktion verdeutlicht. Als ein Ergebnis wird festgehalten, daß die in der außerschulischen Kinder- und Jugendarbeit Tätigen in der Regel bei der Herstellung einer "professionellen Praxis" ihren biographischen Ressourcen mehr vertrauen als der Ausbuchstabierung einer wissenschaftlich abgestützten Fachlichkeit. (DIPF/Text übernommen)On the basis of narrative, biographical interviews, the authors analyze the job-oriented interpretative patterns, plans of action, and professional knowledge of socio-pedagogical actors working with children and adolescents out of school. The results of the qualitatively oriented empirical analysis of the professional habitualization of pedagogues with diverse profiles are exemplified by means of a case reconstruction. The authors come to the conclusion that, in the construction of a "professional practice", those working with children and adolescents out of school usually rely more on their own biographical ressources than on academic professional knowledge. (DIPF/Orig.

Bargaining under Large Risk - An Experimental Analysis -

We present an experimental study to learn about behavior in bargaining situations under large risks. In order to implement realistic risks involved in the field, we calibrate the experimental parameters from an environment involving substantial variation in profits, the motion picture industry. The leading example is the production of a movie that may give rise to a sequel, so actors and producers negotiate sequentially. We analyze the data in light of alternative behavioral approaches to understanding bargaining behavior under large risk