9,798 research outputs found
Einstein-Cartan formulation of Chern-Simons Lorentz-violating Gravity
We consider a modification of the standard Einstein theory in four
dimensions, alternative to R. Jackiw and S.-Y. Pi, Phys. Rev. D 68, 104012
(2003), since it is based on the first-order (Einstein-Cartan) approach to
General Relativity, whose gauge structure is manifest. This is done by
introducing an additional topological term in the action which becomes a
Lorentz-violating term by virtue of the dependence of the coupling on the
space-time point. We obtain a condition on the solutions of the Einstein
equations, such that they persist in the deformed theory, and show that the
solutions remarkably correspond to the classical solutions of a collection of
independent 2+1-d (topological) Chern-Simons gravities. Finally, we study the
relation with the standard second-order approach and argue that they both
coincide to leading order in the modulus of the Lorentz-violating vector field.Comment: Final versio
TFD Extension of Open String Field Theory
We study the application of the rules of Thermo Field Dynamics (TFD) to the
covariant formulation of Open String Field Theory (OSFT). We extend the states
space and fields according to the duplication rules of TFD and construct the
corresponding classical action. The result is interpreted as a theory whose
fields would encode the statistical information of open strings.
The physical spectrum of the free theory is studied through the cohomology of
the extended BRST charge, and, as a result, we get new fields in the spectrum
emerging by virtue of the quantum entanglement and, noticeably, it presents
degrees of freedom that could be identified as those of closed strings. We also
show, however, that their appearing in the action is directly related to the
choice of the inner product in the extended algebra, so that different sectors
of fields could be eliminated from the theory by choosing that product
conveniently.
Finally, we study the extension of the three-vertex interaction and provide a
simple prescription for it whose results at tree-level agree with those of the
conventional theory.Comment: 25 pages, no figures. File format, typos, Abstract and references
modified. New subsection and concluding comments were added. To appear in
Phys. Rev.
SCINTILLA A European project for the development of scintillation detectors and new technologies for nuclear security
Europe monitors transits using radiation detectors to prevent illicit
trafficking of nuclear materials. The SCINTILLA project aims to develop a
toolbox of innovative technologies designed to address different usage cases.
This article will review the scope, approach, results of the first benchmark
campaign and future plans of the SCINTILLA project.Comment: To appear on the Proceedings of the 13th ICATPP Conference on
Astroparticle, Particle, Space Physics and Detectors for Physics
Applications, Villa Olmo (Como, Italy), 23--27 October, 2013, to be published
by World Scientific (Singapore
Molecular characterization of twenty seeded and seedless table grape cultivars (Vitis vinifera L.)
DNA and isoenzyme analyses were used to characterize 20 table grape cultivars including Moscato d'Amburgo, Italia, Sultanina, Bicane and some recently released new varieties. GPI and PGM isoenzyme systems were able to separate the cultivars into 9 groups whereas the 8 microsatellite loci that were analysed revealed a higher discriminating power. In fact, all the cultivars could be distinguished by DNA profiles except Sugraone from its sport Sugrafive. Parentage analysis confirmed that the cultivar Italia was obtained from the crossing Bicane x Moscato d'Amburgo. A difference was observed at one microsatellite locus between Sultanina and the published data for Thompson Seedless, considered to be its synonym. The different microsatellite loci were evaluated for their informativeness
Towards a Conditional and Multi-preferential Approach to Explainability of Neural Network Models in Computational Logic (Extended Abstract)
Optimization of Association Rules Extraction Through Exploitation of Context Dependent Constraints
Evaluation of microsatellite sequence-tagged site markers for characterizing Vitis vinifera cultivars
Twenty four cultivars and clones from Italian germplasm collections were DNA typed for the four sequence-tagged microsatellite sites VVS1-FP, VVS2-JOE, VVS5-FP and VV29-TAM. The analysis was performed using primers labelled with different fluorochromes and using a GENESCAN apparatus. The results were compared with data obtained for samples from Australian collections. By comparing the combined genotype of the studied loci all the cultivars could be singularly distinguished except Favorita, Pigato and Vermentino, thus supporting the hypothesis that all three are the same cultivar. Cultivars common to Italian and Australian germplasm collections were found to have the same genotype indicating that the study of microsatellites as sequence-tagged site (STS) markers is a suitable universal system for worldwide grapevine cultivar identification. Application of the semi-automated GENESCAN system made the analysis of microsatellite STS markers fast and reproducible between laboratories
Bosonization and Duality in Arbitrary Dimensions: New Results
A generic massive Thirring Model in three space-time dimensions exhibits a
correspondence with a topologically massive bosonized gauge action associated
to a self-duality constraint, and we write down a general expression for this
relationship.
We also generalize this structure to dimensions, by adopting the
so-called doublet approach, recently introduced. In particular, a non-
conventional formulation of the bosonization technique in higher dimensions (in
the spirit of ), is proposed and, as an application, we show how fermionic
(Thirring-like) representations for bosonic topologically massive models in
four dimensions may be built up.Comment: Revised version, to appear in Phys. Rev.
LEMONGRASS PLANT LEAF AND CULM AS POTENTIAL SOURCES OF REINFORCEMENT FOR BIO-COMPOSITES
A possible source of natural reinforcement for bio-composites can be represented by lemongrass plant (Cymbopogon flexuosus), a clumped and perennial grass which belongs to the Poaceae family. This plant is extensively used for several applications such as pharmacology, food preservation and cosmetics but, to the best of our knowledge, few papers were published on its use as source for reinforcement of composites and no one article was focused on the comparison between lemongrass leaves and culms as potential source of natural reinforcement. To this aim, a preliminary investigation on leaf and culm fibers was carried out to compare their physical and chemical features as well as their tensile properties. Furthermore, bio-composites based on a biodegradable starch-derived matrix (MaterBi®) and lemongrass leaf and culm particles were manufactured via extrusion and compression molding. For both fillers, two compositions (i.e., 10% and 20 wt.%) were investigated in terms of morphological and mechanical properties
Mouse models of multiple myeloma: Technologic platforms and perspectives
Murine models of human multiple myeloma (MM) are key tools for the study of disease biology as well as for investigation and selection of novel candidate therapeutics for clinical translation. In the last years, a variety of pre-clinical models have been generated to recapitulate a wide spectrum of biological features of MM. These systems range from spontaneous or transgenic models of murine MM, to subcutaneous or orthothopic xenografts of human MM cell lines in immune compromised animals, to platform allowing the engraftment of primary/bone marrowdependent MM cells within a human bone marrow milieu to fully recapitulate human disease. Selecting the right model for specific pre-clinical research is essential for the successful completion of investigation. We here review recent and most known pre-clinical murine, transgenic and humanized models of MM, focusing on major advantages and/or weaknesses in the light of different research aims
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