4,511 research outputs found
Clinical-epidemiological features of HIV-infected patients diagnosed at age of 50 years or older
HIV/AIDS prevention and care efforts are directed to individuals of reproductive age (15–49 yrs). With the extension of sexual life of older people, they became a growing population at risk of HIV infection, usually not included in prevention strategies. In order to evaluate clinical profile of HIV/AIDS pts diagnosed at 50 yrs or older assisted in an HIV outpatient center in Buenos Aires, we retrospectively assessed clinical records of pts initiating care between Jan 1986 and Dec 2011. Age, CD4 cells and viral load (pVL) at HIV diagnosis and most recent value, opportunistic infections (OIs), co-morbidities and antiretroviral therapy (ARV) were recorded. Of 10,998 pts assisted in the 26-yr period, 495 (4.5%) were≥50 yrs old at HIV diagnosis; median annual diagnoses: 18.5 (IQR 3.3–30.3) without significant changes in the last 20 yrs. Demographics: median age 54.7 yrs (IQR 51.8–59.2, rank 50–80), 76.6% male. Risk behavior: HTX 61.4%, MSM 34.1%, others 4.4%. 55.4% of HIV diagnoses occurred during hospitalization or simultaneously with acute OIs. One third (n=176) had AIDS at diagnosis, 24% had history of STDs. HCV co-infection 5.7%, past HBV infection 28.1% and chronic HBV infection 5.1%. Median CD4 cells at HIV diagnosis: 223.5 (13.7%) (IQR 98.8–420.3), initial pVL 60,000 cp/mL (IQR 9,995.5–208,391). 69.3% of pts started ARV therapy during follow-up (FU), and the median time between diagnosis and treatment initiation was 3.4 mo (IQR 0.7–14); 56.9% of them started a non-nucleoside-based regimen (ZDV/3TC/EFV), 28.3% a PI-based regimen (ZDV/3TC/IDV) and 14.6% a nucleoside-based regimen (ZDV/ddI pre-HAART era). After a year (±6 mo), 63.8% pts achieved undetectable pVL and gained 136 CD4 cells from BSL (IQR 83–204). After 40.6 mo of FU (IQR 6.7-89.8), 66.3% are alive, 7.1% died (68.6% of HIV-related diseases) and 26.7% are lost to FU. Co-morbidities were present in 125 (25.3%), mainly hypertension, increased lipids, CVD and DBT. Among treated pts, 70.6% achieved pVL<50 cp/mL, with a median increase of CD4 cells up to 410 (22%) (IQR 281.5–563.9) from BSL. 51% (176) changed ARV therapy due to toxicity/AE: 54.5%, ARV failure: 29.5% and simplification: 14.8%. Stable HIV epidemic in older people reinforce the need of specific prevention approaches, while growing age of HIV individuals in care highlights to consider risks associated to older age. Late presentation to care needs to be specifically addressed. Response to treatment is remarkable high in this population
Coulomb-hadron phase factor and spin phenomena in a wide region of transfer momenta
The Coulomb-hadron interference effects are examined at small and large .
The methods for the definition of spin-dependent parts of hadron scattering
amplitude are presented. The additional contributions to analyzing power
and the double spin correlation parameter owing to the
electromagnetic-hadron interference are determined in the diffraction dip
domain of high-energy elastic hadron scattering.Comment: 9 pages, LaTeX, 4 figure
Field Flows of Dark Energy
Scalar field dark energy evolving from a long radiation- or matter-dominated
epoch has characteristic dynamics. While slow-roll approximations are invalid,
a well defined field expansion captures the key aspects of the dark energy
evolution during much of the matter-dominated epoch. Since this behavior is
determined, it is not faithfully represented if priors for dynamical quantities
are chosen at random. We demonstrate these features for both thawing and
freezing fields, and for some modified gravity models, and unify several
special cases in the literature.Comment: 9 pages, 5 figure
Homogeneous nucleation: Comparison between two theories
The classical nucleation theory of Becker, D\"{o}ring and Zeldovich is
compared with the Langer coarse-grained field approach to the nucleation
phenomenon. Both formalisms have been applied to the condensation from a
supersaturated vapor. It is shown that the nucleation rate derived in the
classical theory can be expressed in a form equivalent to that of the field
nucleation theory. This equivalence serves as an explanation of the puzzling
fact that the numerical predictions of both theories for condensation of Xe and
CO are almost identical though the standard analytical expressions for the
nucleation rates are different. The results obtained can help to link the
theories of nucleation and their approximations.Comment: 12 pages, LaTeX, no figure
Homogeneous nucleation of a non-critical phase near a continuous phase transition
Homogeneous nucleation of a new phase near a second, continuous, transition,
is considered. The continuous transition is in the metastable region associated
with the first-order phase transition, one of whose coexisting phases is
nucleating. Mean-field calculations show that as the continuous transition is
approached, the size of the nucleus varies as the response function of the
order parameter of the continuous transition. This response function diverges
at the continuous transition, as does the temperature derivative of the free
energy barrier to nucleation. This rapid drop of the barrier as the continuous
transition is approached means that the continuous transition acts to reduce
the barrier to nucleation at the first-order transition. This may be useful in
the crystallisation of globular proteins.Comment: 6 pages, 1 figur
Using Molecules to Measure Nuclear Spin-Dependent Parity Violation
Nuclear spin-dependent parity violation arises from weak interactions between
electrons and nucleons, and from nuclear anapole moments. We outline a method
to measure such effects, using a Stark-interference technique to determine the
mixing between opposite-parity rotational/hyperfine levels of ground-state
molecules. The technique is applicable to nuclei over a wide range of atomic
number, in diatomic species that are theoretically tractable for
interpretation. This should provide data on anapole moments of many nuclei, and
on previously unmeasured neutral weak couplings
The Symplectic Penrose Kite
The purpose of this article is to view the Penrose kite from the perspective
of symplectic geometry.Comment: 24 pages, 7 figures, minor changes in last version, to appear in
Comm. Math. Phys
Magnetocaloric Studies of the Peak Effect in Nb
We report a magnetocaloric study of the peak effect and Bragg glass
transition in a Nb single crystal. The thermomagnetic effects due to vortex
flow into and out of the sample are measured. The magnetocaloric signature of
the peak effect anomaly is identified. It is found that the peak effect
disappears in magnetocaloric measurements at fields significantly higher than
those reported in previous ac-susceptometry measurements. Investigation of the
superconducting to normal transition reveals that the disappearance of the bulk
peak effect is related to inhomogeneity broadening of the superconducting
transition. The emerging picture also explains the concurrent disappearance of
the peak effect and surface superconductivity, which was reported previously in
the sample under investigation. Based on our findings we discuss the
possibilities of multicriticality associated with the disappearance of the peak
effect.Comment: 30 pages, 10 figure
Identifying and Indexing Icosahedral Quasicrystals from Powder Diffraction Patterns
We present a scheme to identify quasicrystals based on powder diffraction
data and to provide a standardized indexing. We apply our scheme to a large
catalog of powder diffraction patterns, including natural minerals, to look for
new quasicrystals. Based on our tests, we have found promising candidates
worthy of further exploration.Comment: 4 pages, 1 figur
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