258 research outputs found
Evaluation and optimization of the Sysmex UF1000i system for the screening of urinary tract infection in primary health care elderly patients
Objective Urinary tract infections (UTIs) are a common problem in the elderly population. Urine culture is still considered the "gold standard" to diagnose infection in this population. However, urine cultures are laborious and costly, and most samples will yield no growth. Methods An evaluation was made of the Sysmex UF-1000i flow cytometer as a screening tool for UTI in an elderly population older than 65 years who lived in the community, using 346 urine samples submitted for culture. Results The Receiver Operating Characteristic (ROC) analysis showed a significant difference (P < 0.01) between 0.98 bacteria area under the curve value and 0.82 of white blood cells (WBC). The combination of both counts for screening did not show any improvement in specificity or sensitivity. According to our data, the use of a single cut-off point of 200 bacteria/μL is suggested, in which the sensitivity and specificity were 99.11% and 91.59%, respectively, with a NPV of 99.49%. Moreover, this cut-off value could avoid 60.24% of the samples to be cultured, with a minimal false negative results rate of 0.87%. Conclusions The stratification of age groups stratification helps in selecting a more adjusted Sysmex UF1000i cut-off limit, leading to an improvement in the screening parameters that would imply a better management of these infections, as well as a high reduction in the workload and cost savings
The phase transition and the Quasi-Normal Modes of black Holes
We reexamined the argument that the quasinormal modes could be a probe of the
phase transition of a topological black hole to a hairy configuration by
investigating general scalar perturbations. We found further evidence in the
quasinormal modes for this phase transition. For the general black hole
configurations, we observed that although the quasinormal modes can present us
different phases of different configurations, there is no dramatic change in
the slope of quasinormal frequencies at the critical point of the phase
transition. More detailed studies of quasinormal modes are needed to reveal the
subtle behavior of the phase transition.Comment: Revised version, accepted for publication in JHE
Quasinormal Modes of Extremal BTZ Black Hole
Motivated by several pieces of evidence, in order to show that extreme black
holes cannot be obtained as limits of non-extremal black holes, in this article
we calculate explicitly quasinormal modes for Ba\~{n}ados, Teitelboim and
Zanelli (BTZ) extremal black hole and we showed that the imaginary part of the
frequency is zero. We obtain exact result for the scalar an fermionic
perturbations. We also showed that the frequency is bounded from below for the
existence of the normal modes (non-dissipative modes).Comment: 6 pp. Accepted Classical and Quantum Gravity. Typos corrected and
some references was added. Final Versio
BTZ Black Hole as Solution of 3d Higher Spin Gauge Theory
BTZ black hole is interpreted as exact solution of 3d higher spin gauge
theory. Solutions for free massless fields in BTZ black hole background are
constructed with the help of the star-product algebra formalism underlying the
formulation of 3d higher spin theory. It is shown that a part of higher spin
symmetries remains unbroken for special values of the BTZ parameters.Comment: 31 pages, LaTeX; references correcte
Intermediate Asymptotics of the Kerr Quasinormal Spectrum
We study analytically the quasinormal mode spectrum of near-extremal
(rotating) Kerr black holes. We find an analytic expression for these
black-hole resonances in terms of the black-hole physical parameters: its
Bekenstein-Hawking temperature T_{BH} and its horizon's angular velocity
\Omega, which is valid in the intermediate asymptotic regime
1<<\omega<<1/T_{BH}.Comment: 4 page
Fermions scattering in a three dimensional extreme black hole background
The absorption cross section for scattering of fermions off an extreme BTZ
black hole is calculated. It is shown that, as in the case of scalar particles,
an extreme BTZ black hole exhibits a vanishing absorption cross section, which
is consistent with the vanishing entropy of such object. Additionally, we give
a general argument to prove that the particle flux near the horizon is zero.
Finally we show that the {\it reciprocal space} introduced previously in
\cite{gm} gives rise to the same result and, therefore, it could be considered
as the space where the scattering process takes place in an AdS spacetime.Comment: 15 pages, RevTex4. Revised version. To be published in Class.
Quantum. Gra
The electrospinnability of visco-elastic sugar solutions
It has been proposed that hydrogen bonding plays a role in promoting the electrospinnability of some materials. In this work, the significance of non-covalent interactions in the electrospinnability of aqueous sugar solutions (i.e. mono- and disaccharide) was investigated as a function of carbohydrate concentration. The electrospinnability of concentrated aqueous solutions of glucose, fructose and sucrose was studied by physicochemical and rheological characterization methods, and by subsequently examining the resulting morphology via scanning electron microscopy. The results on the electrospinning of concentrated saccharide solutions indicated the significance of non-covalent interactions on the electrospinning of these systems. Electrospinnability models based on critical concentration and visco-elasto capillary theories were compared with the experimental results. It is shown that visco-elasto capillary theory has the closest correlation with the experimental data. The electrospinnability of highly concentrated saccharide solutions appears to be directly related to the density and intermolecular bonding capacity of the solution
Absorption and quasinormal modes of classical fields propagating on 3D and 4D de Sitter spacetime
We extensively study the exact solutions of the massless Dirac equation in 3D
de Sitter spacetime that we published recently. Using the Newman-Penrose
formalism, we find exact solutions of the equations of motion for the massless
classical fields of spin s=1/2,1,2 and to the massive Dirac equation in 4D de
Sitter metric. Employing these solutions, we analyze the absorption by the
cosmological horizon and de Sitter quasinormal modes. We also comment on the
results given by other authors.Comment: 31 page
Calidad del agua del estero el sauce, valparaíso, chile central water quality in the el sauce estuary, valparaíso, central Chile
Indexación: Scopus.The main objective of this work was to evaluate the water quality of the El Sauce estuary and its tributaries. The El Sauce estuary basin is located in the town of Laguna Verde, Valparaíso, Central Chile. Sampling took place in the summer season of 2013 and 2015, in 11 stations located along the basin, five of them distributed from its origin to its mouth in the sea and six located before entering its tributaries. Point and non-point sources downloaded in its course were identified. The direct discharge of water from a sewage treatment plant in the area of origin of the estuary, and in its middle zone the percolation of a municipal landfill, stand out for their volume. Its mouth is affected by non-point sources of domestic waters in the town of Laguna Verde. The results show that the estuary is a shallow water course, which quality Class 4 (poor) in most of its extension presents due to the content of organic matter, nutrients, chlorides, and fecal contamination, not complying with environmental regulations for any use. There is a lack of management and control plans in the use of this important resource. It has become a risk to the community, who use the water of the stream both to irrigate subsistence agriculture and for recreation with a direct contact at its mouth.https://www.revistascca.unam.mx/rica/index.php/rica/article/view/RICA.534
SIRT1 disruption in human fetal hepatocytes leads to increased accumulation of glucose and lipids
There are unprecedented epidemics of obesity, such as type II diabetes and non-alcoholic fatty liver diseases (NAFLD) in developed countries. A concerning percentage of American children are being affected by obesity and NAFLD. Studies have suggested that the maternal environment in utero might play a role in the development of these diseases later in life. In this study, we documented that inhibiting SIRT1 signaling in human fetal hepatocytes rapidly led to an increase in intracellular glucose and lipids levels. More importantly, both de novo lipogenesis and gluconeogenesis related genes were upregulated upon SIRT1 inhibition. The AKT/FOXO1 pathway, a major negative regulator of gluconeogenesis, was decreased in the human fetal hepatocytes inhibited for SIRT1, consistent with the higher level of gluconeogenesis. These results indicate that SIRT1 is an important regulator of lipid and carbohydrate metabolisms within human fetal hepatocytes, acting as an adaptive transcriptional response to environmental changes
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