2,289 research outputs found
Estimation of renal function by CKD-EPI versus MDRD in a cohort of HIV-infected patients: a cross-sectional analysis
Background: Accurately determining renal function is essential for clinical management of HIV patients. Classically, it has been evaluated by estimating glomerular filtration rate (eGFR) with the MDRD-equation, but today there is evidence that the new Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation has greater diagnostic accuracy. To date, however, little information exists on patients with HIV-infection. This study aimed to evaluate eGFR by CKD-EPI vs. MDRD equations and to stratify renal function according to KDIGO guidelines. Methods: Cross-sectional, single center study including adult patients with HIV-infection. Results: Four thousand five hundred three patients with HIV-infection (864 women19%) were examined. Median age was 45 years (IQR 37-52), and median baseline creatinine was 0.93 mg/dL (IQR 0.82-1.05). A similar distribution of absolute measures of eGFR was found using both formulas (p = 0.548). Baseline median eGFR was 95.2 and 90.4 mL/min/ 1.73 m(2) for CKD-EPI and MDRD equations (p 90 mL/min/1.73 m(2)) in 73% patients and '' mild reduced GFR '' (60-89 mL/min/1.73 m(2)) in 24.3% of the patients, formerly classified as >60 mL/min/1.73 m(2) with MDRD. Conclusions: There was good correlation between CKD-EPI and MDRD. Estimating renal function using CKD-EPI equation allowed better staging of renal function and should be considered the method of choice. CKD-EPI identified a significant proportion of patients (24%) with mild reduced GFR (60-89 mL/min/1.73 m(2)).Red de SidaInstituto de Salud Carlos III, Madrid, SpainEuropean Regional Development Fund (ERDF)Univ Fed Sao Paulo, Kidney Transplant Div, Hosp Rim, Sao Paulo, BrazilUniv Barcelona, Hosp Clin IDIBAPS, Nephrol & Renal Transplantat Serv, Barcelona, SpainHosp Clin Barcelona, Biomed Diag Ctr, Core Lab, Barcelona, SpainHosp Olot, Internal Med Serv, Girona, SpainUniv Girona, Dept Med Sci, Girona, SpainUniv Barcelona, Hosp Clin IDIBAPS, Infect Dis Serv, Barcelona, SpainUniv Fed Sao Paulo, Kidney Transplant Div, Hosp Rim, Sao Paulo, BrazilRed de Sida: RD12/0017/0001Instituto de Salud Carlos III, Madrid, Spain: INT15/00168Web of Scienc
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Exploring the accessibility of deformed digital heritage models
The concept of accessibility has been examined by the scientific community in various fields such as education, health care, social inclusion, disabilities, transport, and tourism. Regarding heritage, the European Commission’s efforts toward accessible cultural heritage are highlighted, along with the use of digitisation and modelling technologies for complex heritage shapes. Thus, this chapter explores relevant scientific research into the accessibility of digital heritage models that represent the assets’ real condition, that is, as-is or as-built models produced using advanced digitisation and modelling technologies. The study emphasises the importance of both physical and semantic aspects of heritage conservation and the need for public awareness and cooperation toward the aimed accessibility. The methodology addresses the search for publications in Scopus and Web of Science and their filtering based on inclusion and exclusion criteria to ensure documents related to the accessibility of deformed digital heritage models are considered. The research concludes that creating accessible deformed digital heritage models is crucial for inclusion and participation from the public and stakeholders, and while some studies achieve accurate as-built geometries and accessibility, there is room for improvement
VLA H53alpha radio recombination line observations of the ultraluminous infrared galaxy Arp 220
We present high angular resolution (0.7'') observations made with the Very
Large Array (VLA) of the radio recombination line (RRL) H53alpha and radio
continuum emission at 43 GHz from the ultraluminous infrared galaxy (ULIRG) Arp
220. The 43 GHz continuum emission shows a compact structure (~2'') with two
peaks separated by ~1'', the East (E) and West (W) components, that correspond
to each galactic nucleus of the merger. The spectral indices for both the E and
W components, using radio continuum images at 8.3 and 43 GHz are typical of
synchrotron emission (alpha ~ -1.0). Our 43 GHz continuum and H53alpha line
observations confirm the flux densities predicted by the models proposed by
Anantharamaiah et al. This agreement with the models implies the presence of
high-density (~ 100,000 cm^-3) compact HII regions (~ 0.1 pc) in Arp 220. The
integrated H53alpha line emission is stronger toward the non-thermal radio
continuum peaks, which are also coincident with the peaks of molecular emission
of the H2CO. The coincidence between the integrated H53alpha and the H2CO maser
line emission suggests that the recent star forming regions, traced by the high
density gas, are located mainly in regions that are close to the two radio
continuum peaks. A velocity gradient of ~ 0.30 km/s/pc in the H53alpha RRL is
observed toward the E component and a second velocity gradient of ~ 0.15
km/s/pc is detected toward the W component. The orientations of these velocity
gradients are in agreement with previous CO, HI and OH observations. The
kinematics of the high-density ionized gas traced by the H53alpha line are
consistent with two counter rotating disks as suggested by the CO and HI
observations.Comment: The original version was published in the ApJ,633,198,2005. This new
version is submitted with the corrected velocity scal
Raphtory: The temporal graph engine for Rust and Python
Raphtory is a platform for building and analysing temporal networks. The library includes
methods for creating networks from a variety of data sources; algorithms to explore their
structure and evolution; and an extensible GraphQL server for deployment of applications built
on top. Raphtory’s core engine is built in Rust, for efficiency, with Python interfaces, for ease
of use. Raphtory is developed by network scientists, with a background in Physics, Applied
Mathematics, Engineering and Computer Science, for use across academia and industry
Mean Field Approximations and Multipartite Thermal Correlations
The relationship between the mean-field approximations in various interacting
models of statistical physics and measures of classical and quantum
correlations is explored. We present a method that allows us to bound the total
amount of correlations (and hence entanglement) in a physical system in thermal
equilibrium at some temperature in terms of its free energy and internal
energy. This method is first illustrated using two qubits interacting through
the Heisenberg coupling, where entanglement and correlations can be computed
exactly. It is then applied to the one dimensional Ising model in a transverse
magnetic field, for which entanglement and correlations cannot be obtained by
exact methods. We analyze the behavior of correlations in various regimes and
identify critical regions, comparing them with already known results. Finally,
we present a general discussion of the effects of entanglement on the
macroscopic, thermodynamical features of solid-state systems. In particular, we
exploit the fact that a dimensional quantum system in thermal equilibrium
can be made to corresponds to a d+1 classical system in equilibrium to
substitute all entanglement for classical correlations.Comment: 17 pages, 6 figure
Renyi Entropy of the XY Spin Chain
We consider the one-dimensional XY quantum spin chain in a transverse
magnetic field. We are interested in the Renyi entropy of a block of L
neighboring spins at zero temperature on an infinite lattice. The Renyi entropy
is essentially the trace of some power of the density matrix of the
block. We calculate the asymptotic for analytically in terms of
Klein's elliptic - function. We study the limiting entropy as a
function of its parameter . We show that up to the trivial addition
terms and multiplicative factors, and after a proper re-scaling, the Renyi
entropy is an automorphic function with respect to a certain subgroup of the
modular group; moreover, the subgroup depends on whether the magnetic field is
above or below its critical value. Using this fact, we derive the
transformation properties of the Renyi entropy under the map and show that the entropy becomes an elementary function of the
magnetic field and the anisotropy when is a integer power of 2, this
includes the purity . We also analyze the behavior of the entropy as
and and at the critical magnetic field and in the
isotropic limit [XX model].Comment: 28 Pages, 1 Figur
Quantum Entanglement in Second-quantized Condensed Matter Systems
The entanglement between occupation-numbers of different single particle
basis states depends on coupling between different single particle basis states
in the second-quantized Hamiltonian. Thus in principle, interaction is not
necessary for occupation-number entanglement to appear. However, in order to
characterize quantum correlation caused by interaction, we use the eigenstates
of the single-particle Hamiltonian as the single particle basis upon which the
occupation-number entanglement is defined. Using the proper single particle
basis, we discuss occupation-number entanglement in important eigenstates,
especially ground states, of systems of many identical particles. The
discussions on Fermi systems start with Fermi gas, Hatree-Fock approximation,
and the electron-hole entanglement in excitations. The entanglement in a
quantum Hall state is quantified as -fln f-(1-f)ln(1-f), where f is the proper
fractional part of the filling factor. For BCS superconductivity, the
entanglement is a function of the relative momentum wavefunction of the Cooper
pair, and is thus directly related to the superconducting energy gap. For a
spinless Bose system, entanglement does not appear in the
Hatree-Gross-Pitaevskii approximation, but becomes important in the Bogoliubov
theory.Comment: 11 pages. Journal versio
Cherenkov Telescope Array Data Management
Very High Energy gamma-ray astronomy with the Cherenkov Telescope Array (CTA)
is evolving towards the model of a public observatory. Handling, processing and
archiving the large amount of data generated by the CTA instruments and
delivering scientific products are some of the challenges in designing the CTA
Data Management. The participation of scientists from within CTA Consortium and
from the greater worldwide scientific community necessitates a sophisticated
scientific analysis system capable of providing unified and efficient user
access to data, software and computing resources. Data Management is designed
to respond to three main issues: (i) the treatment and flow of data from remote
telescopes; (ii) "big-data" archiving and processing; (iii) and open data
access. In this communication the overall technical design of the CTA Data
Management, current major developments and prototypes are presented.Comment: 8 pages, 2 figures, In Proceedings of the 34th International Cosmic
Ray Conference (ICRC2015), The Hague, The Netherlands. All CTA contributions
at arXiv:1508.0589
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