8,015 research outputs found
Importance de l'état énergétique de l'eau sur l'aptitude au tassement de matériaux argileux non saturés
Centro de Informacion y Documentacion Cientifica (CINDOC). C/Joaquin Costa, 22. 28002 Madrid. SPAIN / CINDOC - Centro de Informaciòn y Documentaciòn CientìficaSIGLEESSpai
A heavy quark effective field lagrangian keeping particle and antiparticle mixed sectors
We derive a tree-level heavy quark effective Lagrangian keeping
particle-antiparticle mixed sectors allowing for heavy quark-antiquark pair
annihilation and creation. However, when removing the unwanted degrees of
freedom from the effective Lagrangian one has to be careful in using the
classical equations of motion obeyed by the effective fields in order to get a
convergent expansion on the reciprocal of the heavy quark mass. Then the
application of the effective theory to such hard processes should be sensible
for special kinematic regimes as for example heavy quark pair production near
threshold.Comment: LaTeX, 14 pages, 1 EPS figure
Leptonic universality breaking in Upsilon decays as a probe of new physics
In this work we examine the possible existence of new physics beyond the
standard model which could modify the branching fractions of the leptonic
(mainly tauonic) decays of bottomonium vector resonances below the
threshold. The decay width is factorized as the product of two pieces: a) the
probability of an intermediate pseudoscalar color-singlet state
(coupling to the dominant Fock state of the Upsilon via a magnetic dipole
transition) and a soft (undetected) photon; b) the annihilation width of the
pair into two leptons, mediated by a non-standard CP-odd Higgs boson
of mass about 10 GeV, introducing a quadratic dependence on the lepton mass in
the partial width. The process would be unwittingly ascribed to the
leptonic channel thereby (slightly) breaking lepton universality. A possible
mixing of the pseudoscalar Higgs and bottomonium resonances is also considered.
Finally, several experimental signatures to check out the validity of the
conjecture are discussed.Comment: LaTeX, 22 pages, 2 EPS figure
Effects of maternal subnutrition during early pregnancy on cow hematological profiles and offspring physiology and vitality in two beef breeds
This experiment evaluated the effects of subnutrition during early gestation on hematology in cows (Bos Taurus) and on hematological, metabolic, endocrine, and vitality parameters in their calves. Parda de Montaña and Pirenaica dams were inseminated and assigned to either a control (CONTROL, 100% requirements) or a nutrient‐restricted group (SUBNUT, 65%) during the first third of gestation. Dam blood samples were collected on days 20 and 253 of gestation, and calf samples were obtained during the first days of life. Pirenaica dams presented higher red series parameters than Parda de Montaña dams, both in the first and the last months of gestation. During early pregnancy, granulocyte numbers and mean corpuscular hemoglobin were lower in Pirenaica‐SUBNUT than in Pirenaica‐CONTROL cows. Calves from the SUBNUT cows did not show a physiological reduction in red series values in early life, suggesting later maturation of the hematopoietic system. Poor maternal nutrition affected calf endocrine parameters. Newborns from dystocic parturitions showed lower NEFA concentrations and weaker vitality responses. In conclusion, maternal nutrition had short‐term effects on cow hematology, Pirenaica cows showing a higher susceptibility to undernutrition; and a long‐term effect on their offspring endocrinology, SUBNUT newborns showing lower levels of IGF‐1 and higher levels of cortisol.This work was supported by the Spanish Ministry of Economy and Business and the European Union Regional Development Funds (INIA RTA 2013‐00059‐C02 and INIA RZP 2015‐001) and the Government of Aragon under the Grant Research Group Funds (A14_17R). A. Noya received a PhD grant from INIA‐Government of Aragon
Non-Abelian Giant Gravitons
We argue that the giant graviton configurations known from the literature
have a complementary, microscopical description in terms of multiple
gravitational waves undergoing a dielectric (or magnetic moment) effect. We
present a non-Abelian effective action for these gravitational waves with
dielectric couplings and show that stable dielectric solutions exist. These
solutions agree in the large limit with the giant graviton configurations
in the literature.Comment: 8 pages. Contribution to the proceedings of the RTN workshop in
Leuven, Belgium, September 200
On colouring point visibility graphs
In this paper we show that it can be decided in polynomial time whether or
not the visibility graph of a given point set is 4-colourable, and such a
4-colouring, if it exists, can also be constructed in polynomial time. We show
that the problem of deciding whether the visibility graph of a point set is
5-colourable, is NP-complete. We give an example of a point visibility graph
that has chromatic number 6 while its clique number is only 4
High- production as signals for Double Parton scattering at hadron colliders
We present an analysis of the \psi\psi production from double parton (DP)
sacttering and single parton (SP) scattering in the large p_T region via
color-octet gluon fragmentation. We find that at the Tevatron the DP \psi\psi
production is at the edge of the detectability at present, and at the LHC the
DP cross section will dominate over the SP cross section in the lower p_T(min)
region (i.e., p_T(min)<7GeV). We also conclude that the color-octet mechanism
is of crucial importance to the double j/psi production at high energy hadron
colliders.Comment: Revtex, 12 pages, 3 Postscript figure
Phase mapping of aging process in InN nanostructures: oxygen incorporation and the role of the zincblende phase
Uncapped InN nanostructures undergo a deleterious natural aging process at
ambient conditions by oxygen incorporation. The phases involved in this process
and their localization is mapped by Transmission Electron Microscopy (TEM)
related techniques. The parent wurtzite InN (InN-w) phase disappears from the
surface and gradually forms a highly textured cubic layer that completely wraps
up a InN-w nucleus which still remains from original single-crystalline quantum
dots. The good reticular relationships between the different crystals generate
low misfit strains and explain the apparent easiness for phase transformations
at room temperature and pressure conditions, but also disable the classical
methods to identify phases and grains from TEM images. The application of the
geometrical phase algorithm in order to form numerical moire mappings, and RGB
multilayered image reconstructions allows to discern among the different phases
and grains formed inside these nanostructures. Samples aged for shorter times
reveal the presence of metastable InN:O zincblende (zb) volumes, which acts as
the intermediate phase between the initial InN-w and the most stable cubic
In2O3 end phase. These cubic phases are highly twinned with a proportion of
50:50 between both orientations. We suggest that the existence of the
intermediate InN:O-zb phase should be seriously considered to understand the
reason of the widely scattered reported fundamental properties of thought to be
InN-w, as its bandgap or superconductivity.Comment: 18 pages 7 figure
Experimental observation of fractional topological phases with photonic qudits
Geometrical and topological phases play a fundamental role in quantum theory.
Geometric phases have been proposed as a tool for implementing unitary gates
for quantum computation. A fractional topological phase has been recently
discovered for bipartite systems. The dimension of the Hilbert space determines
the topological phase of entangled qudits under local unitary operations. Here
we investigate fractional topological phases acquired by photonic entangled
qudits. Photon pairs prepared as spatial qudits are operated inside a Sagnac
interferometer and the two-photon interference pattern reveals the topological
phase as fringes shifts when local operations are performed. Dimensions and were tested, showing the expected theoretical values.Comment: 6 pages, 4 figure
A KK-monopole giant graviton in AdS_5 x Y_5
We construct a new giant graviton solution in AdS_5 x Y_5, with Y_5 a
quasi-regular Sasaki-Einstein manifold, consisting on a Kaluza-Klein monopole
wrapped around the Y_5 and with its Taub-NUT direction in AdS_5. We find that
this configuration has minimal energy when put in the centre of AdS_5, where it
behaves as a massless particle. When we take Y_5 to be S^5, we provide a
microscopical description in terms of multiple gravitational waves expanding
into the fuzzy S^5 defined as an S^1 bundle over the fuzzy CP^2. Finally we
provide a possible field theory dual interpretation of the construction.Comment: 11 pages, published versio
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