Search results for "SEP"

Simultaneous screening and quantification of aminoglycoside antibiotics in honey using mixed-mode liquid chromatography with quadrupole time-of-fligh…

2018

An analytical method based on liquid chromatography with quadrupole time-of-flight mass spectrometry has been developed for the simultaneous determination of six aminoglycoside antibiotics in honey. The sample pretreatment included extraction with aqueous trichloroacetic acid followed by solid-phase extraction on Strata-X polymeric reversed phase cartridges. Liquid chromatography separation was performed on an Obelisc R zwitterionic type mixed-mode column. An ionBooster™ heated electrospray source was used and showed enhanced ionization efficiency in comparison to a conventional electrospray source. The observed signal enhancement ranged from 3- (neomycin) to 16-fold (gentamicin C1). A data…

Solution of XXZ and XYZ spin chains with boundaries by separation of variables

2014

In this thesis we give accounts on the solution of the open XXZ and XYZ quantum spin-1/2 chains with the most generic integrable boundary terms. By using the the Separation of Variables method (SoV), due to Sklyanin, we are able, in the inhomogeneous case, to build the complete set of eigenstates and the associated eigenvalues. The characterization of these quantities is made through a maximal system of N quadratic equations, where N is the size of the chain. Different methods, like the Algebraic Bethe ansatz (ABA) or other generalized Bethe ansatz techniques, have been used, in the past, in order to tackle these problems. None of them resulted effective in the reproduction of the full set …

Is splenectomy a treatment option for aseptic abscesses in patients with Crohn's disease?

2009

Signal detection for spread spectrum communication systems with gradient algorithm

2012

Retrieval process of original symbols of a spread spectrum based communication system is tried to be improved by Gradient Algorithm (GA) and Blind Source Separation (BSS) principles. Two simple schemes, based on two energy functions are presented. Time correlation properties of the channel are used as advantages in developing the filter coefficients for the receiver. Direct Sequence - Code Division Multiple Access (DS-CDMA) technique based system setup is used for algorithm testing purposes. This is identified as one of the most stable spread spectrum communication technique where most of the technologies developed for that are highly compatible with High Speed Packet Access (HSPA) transmis…

Concurrent staphylococcal and herpes simplex infections – diagnostic pitfalls. A case report

2018

We describe the case of a six-year-old boy with concurrent staphylococcal septicaemia, herpes simplex virus encephalitis (HSVE), and haemorrhagic erosive oesophagitis. Due to guiding clinical and lab symptoms that suggested a diagnosis of staphylococcal sepsis with central nervous system (CNS) involvement, acyclovir treatment was discontinued a"er three days, but the lack of progress in neurological status, further lab tests, and CT and MRI imaging led the authors to consider possible HSV infection, and this diagnosis was con#rmed by PCR test. Even though the treatment for HSV was applied again, the long gap in acyclovir medication contributed to a severe neurological de#cit and an adverse …

Towards Laser-Textured Antibacterial Surfaces

2018

AbstractEscherichia coli and Staphylococcus aureus bacterial retention on mirror-polished and ultrashort pulse laser-textured surfaces is quantified with a new approach based on ISO standards for measurement of antibacterial performance. It is shown that both wettability and surface morphology influence antibacterial behavior, with neither superhydrophobicity nor low surface roughness alone sufficient for reducing initial retention of either tested cell type. Surface structures comprising spikes, laser-induced periodic surface structures (LIPSS) and nano-pillars are produced with 1030 nm wavelength 350 fs laser pulses of energy 19.1 μJ, 1.01 μJ and 1.46 μJ, respectively. SEM analysis, optic…

Separatrix reconstruction to identify tipping points in an eco-epidemiological model

2018

Many ecological systems exhibit tipping points such that they suddenly shift from one state to another. These shifts can be devastating from an ecological point of view, and additionally have severe implications for the socio-economic system. They can be caused by overcritical perturbations of the state variables such as external shocks, disease emergence, or species removal. It is therefore important to be able to quantify the tipping points. Here we present a study of the tipping points by considering the basins of attraction of the stable equilibrium points. We address the question of finding the tipping points that lie on the separatrix surface, which partitions the space of system traj…

EMERGENCE OF TRAVELLING WAVES IN SMOOTH NERVE FIBRES

2008

International audience; An approximate analytical solution characterizing initial condi- tions leading to action potential ¯ring in smooth nerve ¯bres is determined, using the bistable equation. In the ¯rst place, we present a non-trivial sta- tionary solution wave. Then, we extract the main features of this solution to obtain a frontier condition between the initiation of the travelling waves and a decay to the resting state. This frontier corresponds to a separatrix in the projected dynamics diagram depending on the width and the amplitude of the stationary wave.

Independent component analysis based on symmetrised scatter matrices

2007

A new method for separating the mixtures of independent sources has been proposed recently in [Oja et al. (2006). Scatter matrices and independent component analysis. Austrian J. Statist., to appear]. This method is based on two scatter matrices with the so-called independence property. The corresponding method is now further examined. Simple simulation studies are used to compare the performance of so-called symmetrised scatter matrices in solving the independence component analysis problem. The results are also compared with the classical FastICA method. Finally, the theory is illustrated by some examples. peerReviewed

On Independent Component Analysis with Stochastic Volatility Models

2017

Consider a multivariate time series where each component series is assumed to be a linear mixture of latent mutually independent stationary time series. Classical independent component analysis (ICA) tools, such as fastICA, are often used to extract latent series, but they don't utilize any information on temporal dependence. Also financial time series often have periods of low and high volatility. In such settings second order source separation methods, such as SOBI, fail. We review here some classical methods used for time series with stochastic volatility, and suggest modifications of them by proposing a family of vSOBI estimators. These estimators use different nonlinearity functions to…