819 research outputs found
Interplay of Kondo, Zeeman, and interference effects
We study the effect of a magnetic field in the Kondo regime of a double-
quantum-dot system consisting of a strongly correlated dot (the “side dot”)
coupled to a second, noninteracting dot that also connects two external leads.
We show, using the numerical renormalization group, that application of an in-
plane magnetic field sets up a subtle interplay between electronic
interference, Kondo physics, and Zeeman splitting with nontrivial consequences
for spectral and transport properties. The value of the side-dot spectral
function at the Fermi level exhibits a nonuniversal field dependence that can
be understood using a form of the Friedel sum rule that appropriately accounts
for the presence of an energy- and spin-dependent hybridization function. The
applied field also accentuates the exchange-mediated interdot coupling, which
dominates the ground state at intermediate fields leading to the formation of
antiparallel magnetic moments on the dots. By tuning gate voltages and the
magnetic field, one can achieve complete spin polarization of the linear
conductance between the leads, raising the prospect of applications of the
device as a highly tunable spin filter. The system's low-energy properties are
qualitatively unchanged by the presence of weak on-site Coulomb repulsion
within the second dot
Interplay of Kondo, Zeeman, and interference effects
We study the effect of a magnetic field in the Kondo regime of a double-
quantum-dot system consisting of a strongly correlated dot (the “side dot”)
coupled to a second, noninteracting dot that also connects two external leads.
We show, using the numerical renormalization group, that application of an in-
plane magnetic field sets up a subtle interplay between electronic
interference, Kondo physics, and Zeeman splitting with nontrivial consequences
for spectral and transport properties. The value of the side-dot spectral
function at the Fermi level exhibits a nonuniversal field dependence that can
be understood using a form of the Friedel sum rule that appropriately accounts
for the presence of an energy- and spin-dependent hybridization function. The
applied field also accentuates the exchange-mediated interdot coupling, which
dominates the ground state at intermediate fields leading to the formation of
antiparallel magnetic moments on the dots. By tuning gate voltages and the
magnetic field, one can achieve complete spin polarization of the linear
conductance between the leads, raising the prospect of applications of the
device as a highly tunable spin filter. The system's low-energy properties are
qualitatively unchanged by the presence of weak on-site Coulomb repulsion
within the second dot
Propiedades texturales y reológicas de organogeles de aceite de soja estructurados con ésteres de poliglicerol y propilenglicol durante el almacenamiento
Organogels have emerged as an alternative to the intake of saturated fats. Organogels of soybean oil (SBO) structured with polyglycerol esters (PGE) or propylene glycol esters (PPGE) at different concentrations (0.5, 1.0, 2.0, 3.0, or 4.0%) were formulated. Both emulsifiers at 4% (w/w) concentrations were able to form solid-like organogels and showed thixotropy and low mechanical resistance when compression forces were applied. However, the SBO/PGE (4%) organogels presented lower values for flow curves and micrographs showed a more organized network compared to the SBO/PPGE at 4%. However, higher flow curve values, larger crystals, and mechanical resistance on compression were observed after a two-month storage period of SBO/PPGE compared to SBO/PGE organogels. Both organogels have the potential to be used for diverse food applications although the SBO/PGE was more stable throughout storage.Los organogeles surgieron como una alternativa a la ingesta de grasas saturadas. Se formularon organogeles de aceite de soja (SBO) estructurados con ésteres de poliglicerol (PGE) o ésteres de propilenglicol (PPGE) a diferentes concentraciones (0,5, 1,0, 2,0, 3,0 y 4,0%). Ambos emulsificantes fueron capaces de formar organogeles sólidos con un 4% (p/p) y mostraron tixotropía y baja resistencia mecánica cuando se aplicaron fuerzas de compresión. Sin embargo, los organogeles SBO/PGE (4%) presentaron valores más bajos de curvas de flujo y las microfotografías mostraron una red más organizada en comparación con el SBO/PPGE al 4%. Sin embargo, se observaron valores de curva de flujo más altos, cristales más grandes y resistencia mecánica a la compresión después de dos meses de almacenamiento en el SBO/PPGE en comparación con los organogeles de SBO/PGE. Ambos organogeles tienen potencial para ser usados en la industria alimentaria aunque el organogel SBO/PGE fue más estable durante almacenamiento
Avaliação do estado nutricional na frente de trabalho de Monte Grande, Fogo
Abstract: This study reveals the nutritional status of the workers at Monte Grande, Fogo. The main problenns
detected in the diet are: a) corn is the staple food and its richest part is not used in the preparation of local
dishes, b) the supply of food from animal origin is very low or non-existing, c) there is a very limited number of
food products consumed throughout, and d) the locais do not profit from the food consumed due to inexisting
heaith and sanitary facilities and a limited knowledge of nutrition.INI
SUPRIMENTO ARTERIAL PARA A BOLSA CLOACAL DE GALINHAS (Gallus gallus Linnaeus, 1758) DA LINHAGEM LABEL ROUGE
Foram estudados a origem, o número e a ordenação dos ramos arteriais destinados à
bolsa cloacal em 30 exemplares de Gallus gallus, da linhagem Label Rouge, machos e fêmeas, com
idade entre oito e dez semanas. Após injetado o sistema arterial desses animais com solução corada
de Neoprene látex, seguido de fixação em solução aquosa de formol a 10 % e ulteriormente
dissecados, verificou-se que: a) uma artéria bursocloacal direita esteve presente em 24 dos casos
(80,00%), ao passo que a artéria bursocloacal esquerda foi confirmada em 29 dos exemplares
(96,66%); b) a bolsa cloacal foi irrigada por um ou dois ramos cloacais, oriundos da artéria bursocloacal
ipsilateral; c) a artéria cloacal direita ocorreu em 20 casos (66,66%) e a artéria cloacal esquerda em
9 casos (30,00%), ocasiões em que cediam apenas um ramo; d) o número de ramos arteriais,
independentemente de sua origen, variou de dois a quatro, sendo a sua disposição de maneira
própria para cada exemplar examinado.
Arterial supply for the cloacal bursa of the Rouge Lineage fowl
Gallus gallus (Linnaeus, 1758)
Abstract
A study has been carried out on the origin, number and disposition of the cloacal
bursa arterial branches from tirthy male and female fowls (Gallus gallus), of the Label Rouge lineage,
ageing between eight and ten weeks. After being injected the arterial system of those animals with
a colored solution of Neoprene latex, they were soon after fixed in an 10% aqueous solution of
formalin and dissected. The following observations were carried out: a) a right burso cloacal artery
was present in 24 of the cases (80.00%), while the left bursocloacal artery was confirmed in 29 of the
cases (96.66%); b) the cloacal bursa was irrigated by one or two cloacal branches of the ipsilateral
bursocloacal artery; c) the right cloacal artery is present in 20 cases (66.66%) and the left cloacal
artery in 9 cases (30.00%), with only one branch; d) the number of arterial branches, independent of
origin
Chiral phase boundary of QCD at finite temperature
We analyze the approach to chiral symmetry breaking in QCD at finite
temperature, using the functional renormalization group. We compute the running
gauge coupling in QCD for all temperatures and scales within a simple truncated
renormalization flow. At finite temperature, the coupling is governed by a
fixed point of the 3-dimensional theory for scales smaller than the
corresponding temperature. Chiral symmetry breaking is approached if the
running coupling drives the quark sector to criticality. We quantitatively
determine the phase boundary in the plane of temperature and number of flavors
and find good agreement with lattice results. As a generic and testable
prediction, we observe that our underlying IR fixed-point scenario leaves its
imprint in the shape of the phase boundary near the critical flavor number:
here, the scaling of the critical temperature is determined by the
zero-temperature IR critical exponent of the running coupling.Comment: 39 pages, 8 figure
Hydrogen-Helium Mixtures at High Pressure
The properties of hydrogen-helium mixtures at high pressure are crucial to
address important questions about the interior of Giant planets e.g. whether
Jupiter has a rocky core and did it emerge via core accretion? Using path
integral Monte Carlo simulations, we study the properties of these mixtures as
a function of temperature, density and composition. The equation of state is
calculated and compared to chemical models. We probe the accuracy of the ideal
mixing approximation commonly used in such models. Finally, we discuss the
structure of the liquid in terms of pair correlation functions.Comment: Proceedings article of the 5th Conference on Cryocrystals and Quantum
Crystals in Wroclaw, Poland, submitted to J. Low. Temp. Phys. (2004
The Deuteron Spin-dependent Structure Function g1d and its First Moment
We present a measurement of the deuteron spin-dependent structure function
g1d based on the data collected by the COMPASS experiment at CERN during the
years 2002-2004. The data provide an accurate evaluation for Gamma_1^d, the
first moment of g1d(x), and for the matrix element of the singlet axial
current, a0. The results of QCD fits in the next to leading order (NLO) on all
g1 deep inelastic scattering data are also presented. They provide two
solutions with the gluon spin distribution function Delta G positive or
negative, which describe the data equally well. In both cases, at Q^2 = 3
(GeV/c)^2 the first moment of Delta G is found to be of the order of 0.2 - 0.3
in absolute value.Comment: fits redone using MRST2004 instead of MRSV1998 for G(x), correlation
matrix adde
- …