343 research outputs found
Distal Renal Tubular Acidosis and Sensorineural Deafness with Mutation in the ATP6V1B1 Gene
A acidose tubular renal distal é uma doença rara, caracterizada pela incapacidade na acidificação da urina, condicionando acidose metabólica hiperclorémica, hipocaliémia, hipercalciúria e nefrocalcinose, o que
poderá causar atraso de crescimento, alteração do metabolismo ósseo e insuficiência renal crónica.
A acidose tubular renal distal associada a surdez neurossensorial é uma doença de herança autossómica recessiva, causada por mutações do gene que codifica a subunidade B1 da H+ -ATPase (ATP6V1B1).
Os autores relatam os casos de duas irmãs que apresentaram má progressão ponderal, alterações iónicas, do equilíbrio ácido base e surdez neurossensorial. Foi detectada em ambas as crianças a mutação homozigótica
no gene ATP6V1B1.
Com estes dois casos pretende -se destacar a importância de um diagnóstico precoce nesta patologia rara
Dynamical Symmetry Breaking in Models with the Yukawa Interaction
We discuss models with a massless fermion and a self-interacting massive
scalar field with the Yukawa interaction. The chiral condensate and the fermion
mass are calculated analytically. It is shown that the models have a phase
transition as a function of the squared mass of the scalar field.Comment: 7 pages, no figures, in Eqs. (7) and (11) one coefficient was change
Holographic Roberge-Weiss Transitions
We investigate N=4 SYM coupled to fundamental flavours at nonzero imaginary
quark chemical potential in the strong coupling and large N limit, using
gauge/gravity duality applied to the D3-D7 system, treating flavours in the
probe approximation. The interplay between Z(N) symmetry and the imaginary
chemical potential yields a series of first-order Roberge-Weiss transitions. An
additional thermal transition separates phases where quarks are bound/unbound
into mesons. This results in a set of Roberge-Weiss endpoints: we establish
that these are triple points, determine the Roberge-Weiss temperature, give the
curvature of the phase boundaries and confirm that the theory is analytic in
mu^2 when mu^2~0.Comment: 37 pages, 13 figures; minor comments added, to appear in JHE
Low-energy theorems of QCD and bulk viscosity at finite temperature and baryon density in a magnetic field
The nonperturbative QCD vacuum at finite temperature and a finite baryon
density in an external magnetic field is studied. Equations relating
nonperturbative condensates to the thermodynamic pressure for , and are obtained, and low-energy theorems are derived. A bulk
viscosity is expressed in terms of basic thermodynamical
quantities describing the quark-gluon matter at , , and
. Various limiting cases are also considered.Comment: 12 pages; v2: title changed, new section about bulk viscosity and new
references added; v3: new discussion adde
Holographic Roberge-Weiss Transitions II: Defect Theories and the Sakai-Sugimoto Model
We extend the work of Aarts et al., including an imaginary chemical potential
for quark number into the Sakai-Sugimoto model and codimension k defect
theories. The phase diagram of these models are a function of three parameters,
the temperature, chemical potential and the asymptotic separation of the
flavour branes, related to a mass for the quarks in the boundary theories. We
compute the phase diagrams and the pressure due to the flavours of the theories
as a function of these parameters and show that there are Roberge-Weiss
transitions in the high temperature phases, chiral symmetry restored for the
Sakai-Sugimoto model and deconfined for the defect models, while at low
temperatures there are no Roberge-Weiss transitions. In all the models we
consider the transitions between low and high temperature phases are first
order, hence the points where they meet the Roberge-Weiss lines are triple
points. The pressure for the defect theories scales in the way we expect from
dimensional analysis while the Sakai-Sugimoto model exhibits unusual scaling.
We show that the models we consider are analytic in \mu^2 when \mu^2 is small.Comment: 39 pages, 12 figures. references added, Sakai-Sugimoto section
revised, version to appear in JHE
Use of Hydroacoustic Methods for the Identification of Potential Seabed Habitats for Small Pelagic Fish Schools in the Strait of Sicily
The gluonic condensate from the hyperfine splitting in charmonium
The precision measurement of the hyperfine splitting MeV in the
Fermilab--E835 experiment allows to determine the gluonic condensate with
high accuracy if the gluonic correlation length is fixed. In our
calculations the negative value of MeV is
obtained only if the relatively small fm and
GeV are taken. These values correspond to the ``physical'' string tension
GeV). For fm the hyperfine splitting
is positive and grows for increasing . In particular for fm
and GeV the splitting MeV
is obtained, which is in accord with the recent CLEO result.Comment: 9 pages revtex 4, no figure
Topological susceptibility in Yang-Mills theory in the vacuum correlator method
We calculate the topological susceptibility of the Yang-Mills vacuum using
the field correlator method. Our estimate for the SU(3) gauge group, \chi^{1/4}
= 196(7) MeV, is in a very good agreement with the results of recent numerical
simulations of the Yang-Mills theory on the lattice.Comment: 5 pages (JETP Letters style
Real and imaginary chemical potential in 2-color QCD
In this paper we study the finite temperature SU(2) gauge theory with
staggered fermions for non-zero imaginary and real chemical potential. The
method of analytical continuation of Monte Carlo results from imaginary to real
chemical potential is tested by comparison with simulations performed {\em
directly} for real chemical potential. We discuss the applicability of the
method in the different regions of the phase diagram in the temperature --
imaginary chemical potential plane.Comment: 15 pages, 7 figures; a few comments added; version published on Phys.
Rev.
The critical line from imaginary to real baryonic chemical potentials in two-color QCD
The method of analytic continuation from imaginary to real chemical
potentials is one of the few available techniques to study QCD at finite
temperature and baryon density. One of its most appealing applications is the
determination of the critical line for small : we perform a direct test of
the validity of the method in this case by studying two-color QCD, where the
sign problem is absent. The (pseudo)critical line is found to be analytic
around , but a very large precision would be needed at imaginary
to correctly predict the location of the critical line at real .Comment: Replaced with the version accepted for publication as a Rapid
Communication in Physical Review D
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