849 research outputs found
Strong variable linear polarization in the cool active star II Peg
Magnetic fields of cool active stars are currently studied polarimetrically
using only circular polarization observations. Including linear polarization in
the reconstruction of stellar magnetic fields allows more information about the
magnetic field to be extracted and significantly improves the reliability of
stellar magnetic field maps. The goal of this study is to initiate systematic
observations of active stars in all four Stokes parameters and to identify cool
stars for which linear polarization can be detected at a level sufficient for
Zeeman Doppler imaging (ZDI). Four active RS CVn binaries, II Peg, HR 1099, IM
Peg, and sigma Gem, were observed with the ESPaDOnS spectropolarimeter at the
Canada-France-Hawaii Telescope during a time period from February 2012 to
January 2013. The least-squares deconvolution procedure was applied to derive
mean polarization profiles of all four Stokes parameters. Linear polarization
was detected in all four stars in at least one observation. At the same time,
II Peg showed an exceptionally strong and highly variable linear polarization
signature throughout all observations. This establishes II Peg as the first
promising target for ZDI in all four Stokes parameters and suggests the
feasibility of such an analysis with existing equipment for at least a few of
the most active cool stars.Comment: 5 pages, 2 figures, 1 table; Accepted for publication in MNRA
European Community Multi-Center Trial "Fetal ECG Analysis During Labor": ST plus CTG analysis
This report form part of the European Community Multi-Center Trial "Fetal ECG Analysis during Labor". Aim of this prospective trial was to identify changes in the fetal ECG waveform with cases of verified fetal hypoxia. In this paper we also report on the use of a newly developed automatic system for identification of ST waveform changes (ST Log). All ECG were recorded with the STAN recorder (Neoventa Medical AB, Gothenburg, Sweden). The ECG information was not displayed during labor in order not to influence the clinical management. This report includes data from 320 cases and include six cases of fetal intrapartum hypoxia. Twenty seven cases showed changes in ST waveform. All five cases with the most marked ST change (a rise in T/QRS of >0.10 units and lasting more then 10 minutes) had signs of ongoing intrapartum hypoxia. Six out of six cases with evidence of intrapartum asphyxia, showed ST changes. On the basis of our multi-center trial it appears that the combined analysis of CTG and ST waveform changes provides an accurate way to identify adverse events during labor. The work is continuing with a new STAN recorder developed by Neoventa Medical in Goteborg and currently being tested in a Swedish randomized, controlled multi-center trial
Dianion diagnostics in DESIREE: High-sensitivity detection of from a sputter ion source
A sputter ion source with a solid graphite target has been used to produce
dianions with a focus on carbon cluster dianions, , with
. Singly and doubly charged anions from the source were accelerated
together to kinetic energies of 10 keV per atomic unit of charge and injected
into one of the cryogenic (13 K) ion-beam storage rings of the Double
ElectroStatic Ion Ring Experiment facility at Stockholm University. Spontaneous
decay of internally hot dianions injected into the ring
yielded anions with kinetic energies of 20 keV, which were
counted with a microchannel plate detector. Mass spectra produced by scanning
the magnetic field of a analyzing magnet on the ion injection line
reflect the production of internally hot
dianions with lifetimes in the range of tens of microseconds to milliseconds.
In spite of the high sensitivity of this method, no conclusive evidence of
was found while there was a clear
signal with the expect isotopic distribution. An upper limit is deduced for a
signal that is two orders-of-magnitue smaller than that for
. In addition, and
dianions were detected.Comment: 6 pages, 6 figure
Adsorption of CO on a Platinum (111) surface - a study within a four-component relativistic density functional approach
We report on results of a theoretical study of the adsorption process of a
single carbon oxide molecule on a Platinum (111) surface. A four-component
relativistic density functional method was applied to account for a proper
description of the strong relativistic effects. A limited number of atoms in
the framework of a cluster approach is used to describe the surface. Different
adsorption sites are investigated. We found that CO is preferably adsorbed at
the top position.Comment: 23 Pages with 4 figure
Carotenoids and chlorophyll content in natural soap with addition of vegetative raw material
In the present study, we performed quantitative and qualitative determination of carotenoids and chlorophyll in five samples of natural soap with addition of vegetative raw material: Green tea, Chamerion angustifolium (L.) Holub, Trifolium pratense L., Alchemilla vulgaris L. and Urtica dioica L. There was developed the method of quantitative content of carotenoids and chlorophyll using spectrophotometry with analytical wavelength at 450 nm (carotenoids) and 667 nm (chlorophyll). Qualitative determination was carried out by the comparative TLC analysis. As mobile phases were used in the experiment following a mixed solvent of hexane-acetone (3: 1). Identification of carotenoids was carried out according to standard samples β -carotene and literature data
Multivariate Modelling of Pedestrian Fatality Risk Through on the Spot Accident Investigation
Pedestrians are the most vulnerable users of public roads and represent one of the largest groups of road casualties; their death rate around the world due to vehicle-pedestrian collisions is high and tending to rise. In Spain, as in other countries of the European Union, steps have been taken to reduce the number and consequences of such accidents, with encouraging results in recent years. A key to countering this concern is the accident research activity that has obtained remarkable achievements in different fields, especially when multidisciplinary approaches are taken. This paper describes the development of a multivariate model that is able to detect the most influential parameters on the consequences of vehicle-pedestrian collision and to quantify their impact on pedestrian fatality risk. First, an accident database containing detailed information and parameters of vehicle-pedestrian collisions in Madrid has been developed. The accidents were investigated on the spot by INSIA accident investigation teams and analyzed using advanced reconstruction techniques. The model was then developed with two components: (1) a classification tree that characterizes and selects the explanatory variables, identifying their interactions, and (2) a binary logistic regression to quantify the influence of each variable and interaction resulting from the classification tree. The whole model represents an important tool for identifying, quantifying and predicting the potential impact of measures aimed at reducing injuries in vehicle-pedestrian collisions
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