6,066 research outputs found
Continuum reverberation mapping in a z = 1.41 radio-loud quasar
Q0957+561 was the first discovered gravitationally lensed quasar. The mirage
shows two images of a radio-loud quasar at redshift z = 1.41. The time lag
between these two images is well established around one year. We detected a
very prominent variation in the optical brightness of Q0957+561A at the
beginning of 2009, which allowed us to predict the presence of significant
intrinsic variations in multi-wavelength light curves of Q0957+561B over the
first semester of 2010. To study the predicted brightness fluctuations of
Q0957+561B, we conducted an X-ray, NUV, optical and NIR monitoring campaign
using both ground-based and space-based facilities. The continuum NUV-optical
light curves revealed evidence of a centrally irradiated, standard accretion
disk. In this paper, we focus on the radial structure of the standard accretion
disk and the nature of the central irradiating source in the distant radio-loud
active galactic nucleus (AGN).Comment: 6 pages, 5 figures, Proceedings of The Central Kiloparsec in Galactic
Nuclei-AHAR2011 Conference, to appear in Journal of Physics: Conference
Series (2012
Feynman scaling violation on baryon spectra in pp collisions at LHC and cosmic ray energies
A significant asymmetry in baryon/antibaryon yields in the central region of
high energy collisions is observed when the initial state has non-zero baryon
charge. This asymmetry is connected with the possibility of baryon charge
diffusion in rapidity space. Such a diffusion should decrease the baryon charge
in the fragmentation region and translate into the corresponding decrease of
the multiplicity of leading baryons. As a result, a new mechanism for Feynman
scaling violation in the fragmentation region is obtained. Another numerically
more significant reason for the Feynman scaling violation comes from the fact
that the average number of cutted Pomerons increases with initial energy. We
present the quantitative predictions of the Quark-Gluon String Model (QGSM) for
the Feynman scaling violation at LHC energies and at even higher energies that
can be important for cosmic ray physics.Comment: 21 pages, 11 figures, and 1 table. arXiv admin note: substantial text
overlap with arXiv:1107.1615, arXiv:1007.320
Procedimiento de preparación y materiales conformados basados en compuestos eutécticos binarios o ternarios de circonia
Referencia OEPM: P9600891.-- Fecha de solicitud: 19/04/1996.-- Titular: Consejo Superior de Investigaciones Científicas (CSIC).Procedimiento de preparación y materiales conformados basados en compuestos eutécticos binarios o ternarios de circonia. La presente invención está relacionada con la preparación de materiales con estructuras eutécticas micrométricas basados en mezclas de óxidos, conformados con dimensiones mili y submilimétricas mediante fusión zonal por láser con diferentes sistemas ópticos de focalización y control de los haces de los láseres. Su utilización es en el sector de la producción y conservación de energía, como elementos calefactores, refractarios, cátodos para plasmas de aire, electrodos, en componentes para celdas de combustión, microsensores de gas oxígeno, etc.Peer reviewe
Correlation gap in the optical spectra of the two-dimensional organic metal (BEDT-TTF)_4[Ni(dto)_2]
Optical reflection measurements within the highly conducting (a,b)-plane of
the organic metal (BEDT-TTF)_4[Ni(dto)_2] reveal the gradual development of a
sharp feature at around 200 cm as the temperature is reduced below 150 K. Below
this frequency a narrow Drude-like response is observed which accounts for the
metallic behavior. Since de Haas-von Alphen oscillations at low temperatures
confirm band structure calculations of bands crossing the Fermi energy, we
assign the observed behavior to a two-dimensional metallic state in the
proximity of a correlation induced metal-insulator transition.Comment: 4 pages, 2 figure
ERIGrid Holistic Test Description for Validating Cyber-Physical Energy Systems
Smart energy solutions aim to modify and optimise the operation of existing energy infrastructure. Such cyber-physical technology must be mature before deployment to the actual infrastructure, and competitive solutions will have to be compliant to standards still under development. Achieving this technology readiness and harmonisation requires reproducible experiments and appropriately realistic testing environments. Such testbeds for multi-domain cyber-physical experiments are complex in and of themselves. This work addresses a method for the scoping and design of experiments where both testbed and solution each require detailed expertise. This empirical work first revisited present test description approaches, developed a newdescription method for cyber-physical energy systems testing, and matured it by means of user involvement. The new Holistic Test Description (HTD) method facilitates the conception, deconstruction and reproduction of complex experimental designs in the domains of cyber-physical energy systems. This work develops the background and motivation, offers a guideline and examples to the proposed approach, and summarises experience from three years of its application.This work received funding in the European Community’s Horizon 2020 Program (H2020/2014–2020)
under project “ERIGrid” (Grant Agreement No. 654113)
Chitosan membranes containing micro or nano-size bioactive glass particles : evolution of biomineralization followed by in-situ dynamic mechanical analysis
A newfamilyofbiodegradablepolymer/bioactiveglass(BG)compositematerialshas
emergedbasedontheavailabilityofnano-sizedbioactiveparticles.Suchnovelbiocompo-
sites canhaveenhancedperformance,intermsofmechanicalpropertiesandbioactivity,
and theycanbedesignedtobeusedinboneregenerationapproaches.
In thiswork,membranesofchitosan(CTS)andchitosanwithbioactiveglass(BG)both
micron andnanosizedparticles(CTS/mBG,CTS/nBG,respectively)werepreparedby
solvent casting.Microstructuralandmechanicalpropertieswereevaluatedinorderto
compare theeffectsoftheincorporationofmicro(mBG) andnano(nBG)particlesinthe
chitosan matrix. In vitro bioactivity testswereperformedtocharacterizetheapatitelayer
that isformedonthesurfaceofthematerialafterbeingimmersedinsimulatedbodyfluid
(SBF). Thebiomineralizationprocessonthebiomaterialswasalsofollowedusingnon-
conventionaldynamicmechanicalanalysis(DMA),bothonlineandoffline.InsuchDMA
experiments,thechangeinthestoragemodulus, E0, andthelossfactor,tan d, were
measured asafunctionoftheimmersiontimeinSBF.TheresultsdemonstratedthatCTS/
nBG membranespossessenhancedmechanicalpropertiesandhigherbioactivityin
comparisonwiththeCTS/mBG membranes.SuchresultssuggestthepotentialofnBGfor
the developmentofbioactivecompositesforboneregenerationapplications.This work was financially supported by Foundation for Science and Technology (FCT) by the projects PTDC/QUI/69263/2006, PTDC/CTM-BPC/112774/2009 and, through the scholarship SFRH/BD/64601/2009 granted to Sofia G. Caridade. The authors acknowledge Dr D. Mohn and Prof. W. Stark (Em Zurich) for providing the nBG particles used
Alternative symplectic structures for SO(3,1) and SO(4) four-dimensional BF theories
The most general action, quadratic in the B fields as well as in the
curvature F, having SO(3,1) or SO(4) as the internal gauge group for a
four-dimensional BF theory is presented and its symplectic geometry is
displayed. It is shown that the space of solutions to the equations of motion
for the BF theory can be endowed with symplectic structures alternative to the
usual one. The analysis also includes topological terms and cosmological
constant. The implications of this fact for gravity are briefly discussed.Comment: 13 pages, LaTeX file, no figure
Elastic pp Scattering at LHC Energies
We consider the first LHC data for elastic pp scattering in the framework of
Regge theory with multiple Pomeron exchanges. The simplest eikonal approach
allows one to describe differential elastic cross sections at LHC, as well as
pp and scattering at lower collider energies, on a reasonable level.Comment: 11 pages, 5 figures, and 1 tabl
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