Systematic proof of the existence of Yangian symmetry in chiral Gross-Neveu models

The existence of non-local charges, generating a Yangian symmetry is discussed in generalized chiral Gross-Neveu models. Their conservation can be proven by a finite-loop perturbative computation, the order of which is determined from group theoretic constants and is independent of the number of flavors. Examples, where the 1-loop calculation is sufficient, include the SO(n)-models and other more exotic groups and representations.Comment: 12 pages, LaTe

Polynomial Form Factors in the O(3) Nonlinear sigma-Model

We study the general structure of Smirnov's axioms on form factors of local operators in integrable models. We find various consistency conditions that the form factor functions have to satisfy. For the special case of the $O(3)$ $\sigma$-model we construct simple polynomial solutions for the operators of the spin-field, current, energy-momentum tensor and topological charge density.Comment: 11 pages, plain LaTeX, KFKI-1994-10/

Technological determinism and new media

Technological determinism is the belief that technology is the principal initiator of the society\u27s transformation. The emergence of this theory is usually attributed to the American sociologist Thorstein Veblen, who formulated the causal link between the technology and the society. According to the supporters of technological determinism, any social changes are controlled by the technology, technological development, communications technology and media. The modern information society arises as a result of the development of innovations, new technologies and their social and political implications. Since the establishment of this direction in the early 20th century, two different branches separated: radical and moderate (hard, soft) technological determinism. According to the radical version, the technologies represent a prerequisite for changing the society, the second branch regards the technology only as a key factor that may or may not mean a change. Today, we can quite confidently say that the Internet and the nature of new media is fundamentally changing the structure of the society. The expansion of computers, networks and the Internet has radically changed many aspects of not only human communication, but also the entire society\u27s life. The rising popularity of new media has changed the nature and the way our society and the individuals act – the way we do the shopping, recruit staff, pay taxes, use the library, gain academic degrees and educate ourselves.Through a philosophical analysis, the text examines the nature of contemporary technological determinism, the features of new media and the method they use to affect the creation and distribution of information and knowledge in the education process

Nanosecond surface interferometry measurements on designed and commercial polymers

The effect of the ablation mechanism on surface morphology changes during an ablation process was studied by comparing three different polymers: a triazene polymer, a polyimide and poly(methylmethacrylate) (PMMA) with nanosecond surface interferometry. The triazene polymer, for which only indications for a photochemical ablation mechanism had been detected in previous studies, revealed no surface swelling, which could be attributed to a thermal ablation mechanism. For polyimide, a photothermal ablation mechanism is usually used to describe the ablation process at irradiation wavelengths ≥248nm. However, the interferometric measurements do not show any surface swelling, which would be a clear indication for a thermal ablation mechanism. A surface swelling was only detected for PMMA with irradiation at 248nm and fluences below the threshold of permanent surface modification. The detected phase shift, which is proportional to the change of the film thickness and the refractive index, can be explained by the opposite signs of the thermal expansion coefficient and the thermal refractive-index coefficien

Grid Databases for Shared Image Analysis in the MammoGrid Project

The MammoGrid project aims to prove that Grid infrastructures can be used for collaborative clinical analysis of database-resident but geographically distributed medical images. This requires: a) the provision of a clinician-facing front-end workstation and b) the ability to service real-world clinician queries across a distributed and federated database. The MammoGrid project will prove the viability of the Grid by harnessing its power to enable radiologists from geographically dispersed hospitals to share standardized mammograms, to compare diagnoses (with and without computer aided detection of tumours) and to perform sophisticated epidemiological studies across national boundaries. This paper outlines the approach taken in MammoGrid to seamlessly connect radiologist workstations across a Grid using an "information infrastructure" and a DICOM-compliant object model residing in multiple distributed data stores in Italy and the UKComment: 10 pages, 5 figure

Forward-backward correlations in nucleus-nucleus collisions: baseline contributions from geometrical fluctuations

We discuss the effects of initial collision geometry and centrality bin definition on correlation and fluctuation observables in nucleus-nucleus collisions. We focus on the forward-backward correlation coefficient recently measured by the STAR Collaboration in Au+Au collisions at RHIC. Our study is carried out within two models: the Glauber Monte Carlo code with a `toy' wounded nucleon model and the hadron-string dynamics (HSD) transport approach. We show that strong correlations can arise due to averaging over events in one centrality bin. We, furthermore, argue that a study of the dependence of correlations on the centrality bin definition as well as the bin size may distinguish between these `trivial' correlations and correlations arising from `new physics'.Comment: 12 pages, 6 figure