6,634 research outputs found
Preditores de fibrilação atrial de novo em unidade de cuidados intensivos não cardíaca
OBJECTIVE:
To assess the predictors of de novo atrial fibrillation in patients in a non-cardiac intensive care unit.
METHODS:
A total of 418 hospitalized patients were analyzed between January and September 2016 in a non-cardiac intensive care unit. Clinical characteristics, interventions, and biochemical markers were recorded during hospitalization. In-hospital mortality and length of hospital stay in the intensive care unit were also evaluated.
RESULTS:
A total of 310 patients were included. The mean age of the patients was 61.0 ± 18.3 years, 49.4% were male, and 23.5% presented de novo atrial fibrillation. The multivariate model identified previous stroke (OR = 10.09; p = 0.016) and elevated levels of pro-B type natriuretic peptide (proBNP, OR = 1.28 for each 1,000pg/mL increment; p = 0.004) as independent predictors of de novo atrial fibrillation. Analysis of the proBNP receiver operating characteristic curve for prediction of de novo atrial fibrillation revealed an area under the curve of 0.816 (p 5,666pg/mL. There were no differences in mortality (p = 0.370), but the lengths of hospital stay (p = 0.002) and stay in the intensive care unit (p = 0.031) were higher in patients with de novo atrial fibrillation.
CONCLUSIONS:
A history of previous stroke and elevated proBNP during hospitalization were independent predictors of de novo atrial fibrillation in the polyvalent intensive care unit. The proBNP is a useful and easy- and quick-access tool in the stratification of atrial fibrillation risk.Objetivo:
Avaliar quais os preditores de fibrilação atrial de novo em doentes de uma unidade de cuidados intensivos não cardíaca.
Métodos:
Foram analisados 418 doentes internados entre janeiro e setembro de 2016 em uma unidade de cuidados intensivos não cardíaca. Registaram-se as características clínicas, as intervenções efetuadas e os marcadores bioquímicos durante a internação. Avaliaram-se ainda a mortalidade hospitalar e o tempo de internação hospitalar e na unidade de cuidados intensivos.
Resultados:
Foram incluídos 310 doentes, com média de idades de 61,0 ± 18,3 anos, 49,4% do sexo masculino, 23,5% com fibrilação atrial de novo. O modelo multivariável identificou acidente vascular cerebral prévio (OR de 10,09; p = 0,016) e valores aumentados de proBNP (OR de 1,28 por cada aumento em 1.000pg/mL; p = 0,004) como preditores independentes de fibrilação atrial de novo. A análise por curva Característica de Operação do Receptor do proBNP para predição de fibrilação atrial de novo revelou área sob a curva de 0,816 (p 5.666pg/mL. Não se verificaram diferenças na mortalidade (p = 0,370), porém a duração da internação hospitalar (p = 0,002) e na unidade de cuidados intensivos (p = 0,031) foi superior nos doentes com fibrilação atrial de novo.
Conclusões:
História de acidente vascular cerebral prévio e proBNP elevado em internação constituíram preditores independentes de fibrilação atrial de novo na unidade de cuidados intensivos polivalente. O proBNP pode constituir ferramenta útil, de fácil e rápido acesso na estratificação do risco de fibrilação atrial.info:eu-repo/semantics/publishedVersio
Statistical stability of equilibrium states for interval maps
We consider families of multimodal interval maps with polynomial growth of
the derivative along the critical orbits. For these maps Bruin and Todd have
shown the existence and uniqueness of equilibrium states for the potential
, for close to 1. We show that these
equilibrium states vary continuously in the weak topology within such
families. Moreover, in the case , when the equilibrium states are
absolutely continuous with respect to Lebesgue, we show that the densities vary
continuously within these families.Comment: More details given and the appendices now incorporated into the rest
of the pape
Switching a spin-valve back and forth by current-induced domain wall motion
We have studied the current-induced displacement of a domain wall (DW) in the
permalloy (Py) layer of a Co/Cu/Py spin valve structure at zero and very small
applied field. The displacement is in opposite direction for opposite dc
currents, and the current density required to move DW is only of the order of
10^6 A/cm^2. For H = 3 Oe, a back and forth DW motion between two stable
positions is observed. We also discuss the effect of an applied field on the DW
motion.Comment: 4 pages, 3 figure
The compound Poisson limit ruling periodic extreme behaviour of non-uniformly hyperbolic dynamics
We prove that the distributional limit of the normalised number of returns to
small neighbourhoods of periodic points of non-uniformly hyperbolic dynamical
systems is compound Poisson. The returns to small balls around a fixed point in
the phase space correspond to the occurrence of rare events, or exceedances of
high thresholds, so that there is a connection between the laws of Return Times
Statistics and Extreme Value Laws. The fact that the fixed point in the phase
space is a repelling periodic point implies that there is a tendency for the
exceedances to appear in clusters whose average sizes is given by the Extremal
Index, which depends on the expansion of the system at the periodic point.
We recall that for generic points, the exceedances, in the limit, are
singular and occur at Poisson times. However, around periodic points, the
picture is different: the respective point processes of exceedances converge to
a compound Poisson process, so instead of single exceedances, we have entire
clusters of exceedances occurring at Poisson times with a geometric
distribution ruling its multiplicity.
The systems to which our results apply include: general piecewise expanding
maps of the interval (Rychlik maps), maps with indifferent fixed points
(Manneville-Pomeau maps) and Benedicks-Carleson quadratic maps.Comment: To appear in Communications in Mathematical Physic
Avaliação Tóxica, Citotóxica e Mutagênica de Arilaminonaftoquinonas Sintéticas
Profa. Dra. Maria do Carmo Pimentel Batitucci, orientador - UFES
2- Profa. Dra. Flávia de Paula, examinador interno - UFES
3- Profa. Dra. Maria Aparecida Marin Morales, examinador externo - UNESP - Rio
Claro
Electrical current-driven pinhole formation and insulator-metal transition in tunnel junctions
Current Induced Resistance Switching (CIS) was recently observed in thin
tunnel junctions (TJs) with ferromagnetic (FM) electrodes and attributed to
electromigration of metallic atoms in nanoconstrictions in the insulating
barrier. The CIS effect is here studied in TJs with two thin (20 \AA)
non-magnetic (NM) Ta electrodes inserted above and below the insulating
barrier. We observe resistance (R) switching for positive applied electrical
current (flowing from the bottom to the top lead), characterized by a
continuous resistance decrease and associated with current-driven displacement
of metallic ions from the bottom electrode into the barrier (thin barrier
state). For negative currents, displaced ions return into their initial
positions in the electrode and the electrical resistance gradually increases
(thick barrier state). We measured the temperature (T) dependence of the
electrical resistance of both thin- and thick-barrier states ( and R
respectively). Experiments showed a weaker R(T) variation when the tunnel
junction is in the state, associated with a smaller tunnel contribution.
By applying large enough electrical currents we induced large irreversible
R-decreases in the studied TJs, associated with barrier degradation. We then
monitored the evolution of the R(T) dependence for different stages of barrier
degradation. In particular, we observed a smooth transition from tunnel- to
metallic-dominated transport. The initial degradation-stages are related to
irreversible barrier thickness decreases (without the formation of pinholes).
Only for later barrier degradation stages do we have the appearance of metallic
paths between the two electrodes that, however, do not lead to metallic
dominated transport for small enough pinhole radius.Comment: 10 pages, 3 figure
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