State-of-the-art survey of dissimilar metal joining by solid state welding

State-of-the-art of dissimilar metal joining by solid state diffusion bonding and roll and press welding, emphasizing stainless steel and aluminum allo

Cosmological Constant in LQG Vertex Amplitude

A new q-deformation of the Euclidean EPRL/FK vertex amplitude is proposed by using the evaluation of the Vassiliev invariant associated with a 4-simplex graph (related to two copies of quantum SU(2) group at different roots of unity) embedded in a 3-sphere. We show that the large-j asymptotics of the q-deformed vertex amplitude gives the Regge action with a cosmological constant. In the end we also discuss its relation with a Chern-Simons theory on the boundary of 4-simplex.Comment: 6 pages, 5 figures, result and presentation improve

Cluster growth in the dynamical Erdös-Rényi process with forest fires

We investigate the growth of clusters within the forest fire model of Ráth and Tóth [EJP, vol 14, paper no 45]. The model is a continuous-time Markov process, similar to the dynamical Erdős-Rényi random graph but with the addition of so-called fires. A vertex may catch fire at any moment and, when it does so, causes all edges within its connected cluster to burn, meaning that they instantaneously disappear. Each burned edge may later reappear. We give a precise description of the process CtCt of the size of the cluster of a tagged vertex, in the limit as the number of vertices in the model tends to infinity. We show that CtCt is an explosive branching process with a time-inhomogeneous offspring distribution and instantaneous return to 1 on each explosion. Additionally, we show that the characteristic curves used to analyse the Smoluchowski-type coagulation equations associated to the model have a probabilistic interpretation in terms of the process CtCt

Finite Number of States, de Sitter Space and Quantum Groups at Roots of Unity

This paper explores the use of a deformation by a root of unity as a tool to build models with a finite number of states for applications to quantum gravity. The initial motivation for this work was cosmological breaking of supersymmetry. We explain why the project was unsuccessful. What is left are some observations on supersymmetry for q-bosons, an analogy between black holes in de Sitter and properties of quantum groups, and an observation on a noncommutative quantum mechanics model with two degrees of freedom, depending on one parameter. When this parameter is positive, the spectrum has a finite number of states; when it is negative or zero, the spectrum has an infinite number of states. This exhibits a desirable feature of quantum physics in de Sitter space, albeit in a very simple, non-gravitational context.Comment: 25 pages, 5 figure

Magellanic Cloud X-ray Sources: III. Completion of a ROSAT Survey

This paper concludes a series of three papers presenting ROSAT High-Resolution Imager (HRI) observations of unidentified Einstein and serendipitous ROSAT X-ray sources in the direction of the Magellanic Clouds. Accurate positions and fluxes have been measured for these sources. Optical photometry and spectroscopy were obtained to search for identifications in order to determine the physical nature of these sources. The present paper includes new data for 24 objects; identifications are given or confirmed for 30 sources. For six sources optical finding charts showing the X-ray positions are provided. The results from this program are summarized, showing the populations of luminous X-ray sources in the Magellanic Clouds are quite different from those in the Galaxy.Comment: 28 pages, 2 figures; to appear in Astronomical Journa

Spacetime as a Feynman diagram: the connection formulation

Spin foam models are the path integral counterparts to loop quantized canonical theories. In the last few years several spin foam models of gravity have been proposed, most of which live on finite simplicial lattice spacetime. The lattice truncates the presumably infinite set of gravitational degrees of freedom down to a finite set. Models that can accomodate an infinite set of degrees of freedom and that are independent of any background simplicial structure, or indeed any a priori spacetime topology, can be obtained from the lattice models by summing them over all lattice spacetimes. Here we show that this sum can be realized as the sum over Feynman diagrams of a quantum field theory living on a suitable group manifold, with each Feynman diagram defining a particular lattice spacetime. We give an explicit formula for the action of the field theory corresponding to any given spin foam model in a wide class which includes several gravity models. Such a field theory was recently found for a particular gravity model [De Pietri et al, hep-th/9907154]. Our work generalizes this result as well as Boulatov's and Ooguri's models of three and four dimensional topological field theories, and ultimately the old matrix models of two dimensional systems with dynamical topology. A first version of our result has appeared in a companion paper [gr-qc\0002083]: here we present a new and more detailed derivation based on the connection formulation of the spin foam models.Comment: 32 pages, 2 figure

Latent profile analysis of the Five Facet Mindfulness Questionnaire in a sample with a history of recurrent depression

This is the final version. Available from the publisher via the DOI in this record.Background: Extending previous research, we applied latent profile analysis in a sample of adults with a history of recurrent depression to identify subgroups with distinct response profiles on the Five Facet Mindfulness Questionnaire and understand how these relate to psychological functioning. Method: The sample was randomly divided into two subsamples to first examine the optimal number of latent profiles (test sample; n = 343) and then validate the identified solution (validation sample; n = 340). Results: In both test and validation samples, a four-profile solution was revealed where two profiles mapped broadly onto those previously identified in nonclinical samples: “high mindfulness” and “nonjudgmentally aware.” Two additional subgroups, “moderate mindfulness” and “very low mindfulness,” were observed. “High mindfulness” was associated with the most adaptive psychological functioning and “very low mindfulness” with the least adaptive. Conclusions: In most people with recurrent depression, mindfulness skills are expressed evenly across different domains. However, in a small minority a meaningful and replicable uneven profile indicating nonjudgmental awareness is observable. Current findings require replication and future research should examine the extent to which profiles change from periods of wellness to illness in people with recurrent depression and how profiles are influenced by exposure to mindfulness-based intervention.Economic and Social Research Council (ESRC)Sussex Partnership NHS Foundation TrustNational Institute for Health Research (NIHR)Wellcome Trus

Просвещение как форма популяризации культурно- художественных достижений этнических меньшинств Украины: тенденции 1990-2000-х годов

У статті розглянуто місце і роль просвітництва у популяризації культурно- мистецьких надбань етноменшин. На основі специфічного методологічного інструментарію проаналізовано відповідність популяризації культурно-мистецьких надбань – стратегічними цілями – визнання поліетнічного характеру українського суспільства, розбудові соціокультурного середовища і духовному розвитку етносів. Підкреслено, що в Україні діяла розгалужена мережа музеїв, де діяли спеціальні підрозділи – відділи, центри, експозиції тощо. Проаналізовані напрямки науково – дослідної роботи музеїв та виокремлена її просвітницької складової.В статье рассмотрены место и роль просвещения в популяризации культурно - художественных достижений этнических меньшинств. На основе специфического методологического инструментария проанализированы соответствие популяризации культурно - художественных достижений - стратегическими целями - признание полеэтнического характера украинского общества, развитии социокультурной среды и духовном развитии этносов. Подчеркнуто, что в Украине действовала разветвленная сеть музеев, в которых действовали специальные подразделения - отделы, центры, экспозиции и т.д. Проанализованы направления научно - исследовательской работы музеев с выделением ее просветительской составляющей.On the basis of archival, statistical materials, analytical inputs predecessors considered the place and role of education in promoting cultural - artistic achievements of ethnic minorities. Nonfiction includes the problems of cultural heritage of the Ukrainian people is partly considered problem areas, shapes, nature education. Importance designated problem is primarily due to the need to have a clear understanding of the mechanism solutions independent state problems of interethnic relations. Found that in Ukraine there and operated an extensive network of structures that were engaged in the popularization of cultural - artistic achievements of Ukraine’s ethnic groups: governments, national - cultural societies, cultural institutions. We considered the prospect of continuity and the protection and conservation of heritage. Considerable attention is given to finding areas of education: conducting scientific - practical conferences, advocacy through the museums, the publication of the relevant literature. First in the historiography on the basis of specific methodological tools to analyze the relevant promotion of cultural - artistic achievements - the strategic objectives - recognition of the field of an ethnic nature of Ukrainian society, the development of social and cultural environment and spiritual development of ethnic groups. Particular attention is given to explaining participation in the process of popularizing the achievements of local history museums in Ukraine. Stress that Ukraine had an extensive network of museums that had special units - departments, centers, exposure, etc.. Directions of scientific - research museums and highlighted its educational component. Significant place in the article devoted to subjects found clarification of the regional museum