8 research outputs found
Numerical integration rules with improved accuracy close to singularities
Sometimes it is necessary to obtain a numerical integration using only
discretised data. In some cases, the data contains singularities which position
is known but does not coincide with a discretisation point, and the jumps in
the function and its derivatives are available at these positions. The
motivation of this paper is to use the previous information to obtain numerical
quadrature formulas that allow approximating the integral of the discrete data
over certain intervals accurately. This work is devoted to the construction and
analysis of a new nonlinear technique that allows to obtain accurate numerical
integrations of any order using data that contains singularities, and when the
integrand is only known at grid points. The novelty of the technique consists
in the inclusion of correction terms with a closed expression that depends on
the size of the jumps of the function and its derivatives at the singularities,
that are supposed to be known. The addition of these terms allows recovering
the accuracy of classical numerical integration formulas even close to the
singularities, as these correction terms account for the error that the
classical integration formulas commit up to their accuracy at smooth zones.
Thus, the correction terms can be added during the integration or as
post-processing, which is useful if the main calculation of the integral has
been already done using classical formulas. The numerical experiments performed
allow us to confirm the theoretical conclusions reached in this paper.Comment: 23 pages, 5 Figures, 3 Table
How does Helicobacter pylori infection affect gastric alcohol dehydrogenase activity in patients with gastritis
Regulation of Banana Phytoene Synthase (MaPSY) Expression, Characterization and Their Modulation under Various Abiotic Stress Conditions
International Nosocomial Infection Control Consortiu (INICC) report, data summary of 43 countries for 2007-2012. Device-associated module
We report the results of an International Nosocomial Infection Control Consortium (INICC) surveillance study from January 2007-December 2012 in 503 intensive care units (ICUs) in Latin America, Asia, Africa, and Europe. During the 6-year study using the Centers for Disease Control and Prevention's (CDC) U.S. National Healthcare Safety Network (NHSN) definitions for device-associated health care–associated infection (DA-HAI), we collected prospective data from 605,310 patients hospitalized in the INICC's ICUs for an aggregate of 3,338,396 days. Although device utilization in the INICC's ICUs was similar to that reported from ICUs in the U.S. in the CDC's NHSN, rates of device-associated nosocomial infection were higher in the ICUs of the INICC hospitals: the pooled rate of central line–associated bloodstream infection in the INICC's ICUs, 4.9 per 1,000 central line days, is nearly 5-fold higher than the 0.9 per 1,000 central line days reported from comparable U.S. ICUs. The overall rate of ventilator-associated pneumonia was also higher (16.8 vs 1.1 per 1,000 ventilator days) as was the rate of catheter-associated urinary tract infection (5.5 vs 1.3 per 1,000 catheter days). Frequencies of resistance of Pseudomonas isolates to amikacin (42.8% vs 10%) and imipenem (42.4% vs 26.1%) and Klebsiella pneumoniae isolates to ceftazidime (71.2% vs 28.8%) and imipenem (19.6% vs 12.8%) were also higher in the INICC's ICUs compared with the ICUs of the CDC's NHSN