118 research outputs found
Scalar and vector meson exchange in V->P0P0gamma decays
The scalar contributions to the radiative decays of light vector mesons into
a pair of neutral pseudoscalars, , are studied within the
framework of the Linear Sigma Model. This model has the advantage of
incorporating not only the scalar resonances in an explicit way but also the
constraints required by chiral symmetry. The experimental data on
, ,
and are satisfactorily accommodated in our
framework. Theoretical predictions for ,
, and the ratio are also given.Comment: 42 pages, 11 figures. A new paragraph explaining the seminal
contribution of Ref. [19] is adde
Sobre el origen y la cronología del trípode de varillas de La Clota (Calaceite, Teruel): nuevos datos arqueométricos
New archaeometric data on the fragments of the rod tripod of Cypriote type found at the site of La Clota (Calaceite) enable the reassessment of this artefact from a new perspective. The most important results emerging from this work are related to the method of manufacture by lost-wax casting, to the fact that it is a ternary alloy and, above all, the fact that the lead used came from the Iberian Peninsula. These new data, together with those already known about the influence of the Cypriot-Levantineinfluenced bronze-work in the central and western Mediterranean, indicate that the piece is of local manufacture and lead to a discussion of this type of object as a whole.Los nuevos datos arqueométricos sobre los fragmentos de trípode de varillas de tipo chipriota de La Clota (Calaceite) permiten considerarlo desde una nueva perspectiva. Los más significativos son su manufactura a la cera perdida, el hecho de que se trate de una aleación ternaria y, sobre todo, que el plomo utilizado en ella sea de procedencia peninsular. Estos datos, sumados a los ya conocidos sobre la broncística de influencia chipro-levantina en el Extremo Occidente, indican una manufactura peninsular e invitan a reconsiderar de forma global la pieza
Technologies for Cost-Effective UDWDM-PONs
New technologies for ultradense WDM-PON (udWDM-PON), enabled by coherent techniques and low-cost devices, are developed for an efficient utilization of the optical spectrum, revealing that the 'Wavelength-to-the-User' concept can be feasible. In this paper, an udWDM-PON with only 6.25-GHz channel spacing is implemented with conventional DFB lasers, for a splitter-based PON infrastructure with 256 ONUs. The results of the analysis of udWDM access network architecture with respect to their associated complexity, cost, and migration scenarios, exhibit the potential for higher aggregate throughput, higher split ratios, and node consolidation, when compared to competing technologies
Macro-regional scale of silver production in Iberia during the 1st millennium BC in the context of Mediterranean contacts.
The extraction of silver has been traditionally considered one of the main incentives for the Phoenician expansion through the Mediterranean and their settlement in Iberia. In this paper we approach the organization of silver production in Iberia during the Early Iron Age through the study of productive evidence currently available and the development of Lead Isotope Analysis (LIA). Previous results (Hunt, 2003; Stos Gale 2001; Kassianidou, 1992) are considered in the light of new data. The extraction of silver from complex minerals is conspicuously intensified in Southwest Iberia. Imports of exogenous lead, needed for the extraction of silver from these complex minerals, stand out. Flows of lead come in from other Iberian regions such as Gádor, Cartagena/Mazarrón, Linares or even the mining district of Molar-Belmunt-Falset (MBF) in Catalonia. This picture reveals an organization of silver production much more complex than initially thought, with the needed articulation of an exchange network of raw materials at a macro-territorial scale embracing almost all Iberia. Socioeconomic implications that control of these distributions networks of lead could have had are also discussed
Comercio protohistórico: el registro del Nordeste peninsular y circulación de mineral de plomo en Ibiza y el Bajo Priorato (Tarragona)
Our recent research shows that lead from the Baix Priorat (Tarragona) mining area circulated in the Phoenician-Tartessian sphere. However, archaeometallurgical analysis of a group of ore and metallic samples from the island of Ibiza reveals the exploitation of local galena, whose use co-existed on the sa Caleta site with ores from Cartagena; on the other hand, lead from the Priorat mining area is not attested. If we also take into account the information provided by 7th-6th centuries BC pottery from Ibiza and Catalonia, a variety of trade networks between the south and the north-east of Iberia emerges
El cobre de Linares (Jaén) como elemento vinculado al comercio fenicio en El Calvari de El Molar (Tarragona)
The settlement and the necropolis of El Calvari (El Molar, Tarragona), dated between the end of the Late Bronze Age and the Early Iron Age, provided various copper-based objects and melting wastes. The archaeological site is located in a mining district, the Molar-Bellmunt-Falset (MBF) area, which presents rich deposits mainly of non-argentiferous lead and copper. Lead isotope analyses performed on some lead-based materials recovered from El Calvari show that these mines were already being exploited at this time. However, lead isotope analyses of the copper-based metals indicate that neither the ones from the site nor those from the necropolis can be related to local mineral resources. Indeed, a great part of these items originates from the Linares mines (Jaén) and, in a smaller part, from mines in the Almería province. In this paper we will discuss arguments supporting the possibility of import of ingots or of finished objects as part of the Phoenician trade in northeastern Iberia
Chaste: an open source C++ library for computational physiology and biology
Chaste - Cancer, Heart And Soft Tissue Environment - is an open source C++ library for the computational simulation of mathematical models developed for physiology and biology. Code development has been driven by two initial applications: cardiac electrophysiology and cancer development. A large number of cardiac electrophysiology studies have been enabled and performed, including high performance computational investigations of defibrillation on realistic human cardiac geometries. New models for the initiation and growth of tumours have been developed. In particular, cell-based simulations have provided novel insight into the role of stem cells in the colorectal crypt. Chaste is constantly evolving and is now being applied to a far wider range of problems. The code provides modules for handling common scientific computing components, such as meshes and solvers for ordinary and partial differential equations (ODEs/PDEs). Re-use of these components avoids the need for researchers to "re-invent the wheel" with each new project, accelerating the rate of progress in new applications. Chaste is developed using industrially-derived techniques, in particular test-driven development, to ensure code quality, re-use and reliability. In this article we provide examples that illustrate the types of problems Chaste can be used to solve, which can be run on a desktop computer. We highlight some scientific studies that have used or are using Chaste, and the insights they have provided. The source code, both for specific releases and the development version, is available to download under an open source Berkeley Software Distribution (BSD) licence at http://www.cs.ox.ac.uk/chaste, together with details of a mailing list and links to documentation and tutorials
J/psi->VP decays and the quark and gluon content of the eta and eta'
The - pseudoscalar mixing angle and the gluonium content
of the meson are deduced from an updated phenomenological
analysis of decays into a vector and a pseudoscalar meson. In absence
of gluonium, the value of the mixing angle in the quark-flavour basis is found
to be . In presence of gluonium, the values for the
mixing angle and the gluonic content of the wave function are
and ,
respectively. The newly reported values of by the BABAR
and BES Collaborations are crucial to get a consistent description of data.Comment: 7 pages, 1 figure, uses svjour style. Comments on the relationship
between J/psi to VP and V to Pgamma decays and on the neglected contributions
together with an asymmetric treatment of errors are include
- …