417 research outputs found
Comparison of the Automated Oscillometric Method With the Gold Standard Doppler Ultrasound Method to Access the Ankle-Brachial Pressure Index
Objective: Despite its screening interest, the ankle-brachial pressure index (ABPI) remains uncommon in general practice, because it needs training and specific devices as Doppler. Easier methods such as the use of automated oscillometric devices may facilitate the peripheral arterial diseases (PADs) screening. We wanted to assess the reliability of the automated oscillometric measurement of the ABPI, compared with the gold standard Doppler ultrasound measurement. Patients and Method: In 287 patients aged 65 years or older without diagnosed PAD, we performed ABPI measurements with oscillometric and Doppler devices. Reproducibility was assessed by the intraclass correlation coefficient of agreement (R) and the Bland and Altman method. Results: The intermethod reliability was bad (R = .346, 95% CI = (0.268-0.420)), with a large confidence interval of the individual differences between the 2 methods: 95% CI = (â0.183-0.346). Conclusion: Automatic oscillometric devices cannot be recommended as reliable methods for ABPI measurement
Monitoring edge-geodetic sets in graphs
We introduce a new graph-theoretic concept in the area of network monitoring.
In this area, one wishes to monitor the vertices and/or the edges of a network
(viewed as a graph) in order to detect and prevent failures. Inspired by two
notions studied in the literature (edge-geodetic sets and
distance-edge-monitoring sets), we define the notion of a monitoring
edge-geodetic set (MEG-set for short) of a graph as an edge-geodetic set
of (that is, every edge of lies on some shortest path
between two vertices of ) with the additional property that for every edge
of , there is a vertex pair of such that lies on
\emph{all} shortest paths between and . The motivation is that, if some
edge is removed from the network (for example if it ceases to function),
the monitoring probes and will detect the failure since the distance
between them will increase.
We explore the notion of MEG-sets by deriving the minimum size of a MEG-set
for some basic graph classes (trees, cycles, unicyclic graphs, complete graphs,
grids, hypercubes,...) and we prove an upper bound using the feedback edge set
of the graph
Characterizing extremal digraphs for identifying codes and extremal cases of Bondy's theorem on induced subsets
An identifying code of a (di)graph is a dominating subset of the
vertices of such that all distinct vertices of have distinct
(in)neighbourhoods within . In this paper, we classify all finite digraphs
which only admit their whole vertex set in any identifying code. We also
classify all such infinite oriented graphs. Furthermore, by relating this
concept to a well known theorem of A. Bondy on set systems we classify the
extremal cases for this theorem
Ătude comparative tensiomĂštre automatique versus doppler Ă ultrasons dans la mesure de lâindex de pression systolique Ă la cheville (Ipsc)
ObjectifLâĂ©valuation de lâindex de pression systolique Ă la cheville (IPSC) est la mĂ©thode non invasive la plus simple de dĂ©pistage de lâartĂ©riopathie des membres infĂ©rieurs (AOMI) mais reste peu usitĂ©e en pratique courante, car elle est chronophage, implique un Ă©quipement et une formation appropriĂ©s. Le but de notre Ă©tude est dâĂ©valuer la validitĂ© et la fiabilitĂ© de la mesure de lâIPSC Ă lâaide dâun tensiomĂštre automatique par comparaison avec les rĂ©sultats obtenus par doppler continu, mĂ©thode de rĂ©fĂ©rence. MĂ©thodes Les patients de 65 ans et plus hospitalisĂ©s au CHU dâAngers de juillet 2008 à mars 2009 en mĂ©decine interne et nâayant pas dâAOMI documentĂ©e au moment de lâinclusion ont participĂ© Ă lâĂ©tude. Les critĂšres dâexclusion Ă©taient la prĂ©sence dâune fibrillation auriculaire et une incompressibilitĂ© des artĂšres distales des membres infĂ©rieurs. Pour chaque patient, lâIPSC a Ă©tĂ© Ă©valuĂ© par tensiomĂštre automatique et par la mĂ©thode Doppler de rĂ©fĂ©rence ; ces mesures Ă©tant faites par le mĂȘme examinateur. La concordance entre les deux mesures Ă©tait apprĂ©ciĂ©e par la mĂ©thode de Bland et Altman et le coefficient de corrĂ©lation intraclasse (ICC). RĂ©sultats Sur 287 patients participant Ă lâĂ©tude, 221 ont Ă©tĂ©s inclus. Cinquante-six (25 %) de ces patients avaient un IPSC < 0,90. La concordance entre les deux mĂ©thodes Ă©tait mĂ©diocre : ICC Ă 0,35 ± 0,08 et moyenne Ă 0,08 ± 0,26 selon la mĂ©thode de Bland et Altman. Conclusion La mĂ©thode de dĂ©pistage de lâAOMI par mesure de lâIPSC par tensiomĂštre automatique ne peut ĂȘtre retenue comme une alternative Ă la mĂ©thode Doppler
Observing the high redshift universe using the VIMOS-IFU
We describe the advantages of using Integral Field Spectroscopy to observe
deep fields of galaxy. The VIMOS Integral Field Unit is particularly suitable
for this kind of studies thanks to its large field-of-view (~ 1 arcmin^2).
After a short description of the VIMOS-IFU data reduction, we detail the main
scientific issues which can be addressed using observations of the Hubble Deep
Field South with a combination of Integral Field Spectroscopy and broad band
optical and Near-Infrared imaging.Comment: 4 pages, accepted for publishing in AN (ref. proc. of Euro3D Science
workshop, IoA Cambridge, May 2003
Galactic conformity and central/satellite quenching, from the satellite profiles of M* galaxies at 0.4 < z < 1.9 in the UKIDSS UDS
We explore the redshift evolution of a curious correlation between the star formation properties of central galaxies and their satellites (âgalactic conformity') at intermediate to high redshift (0.4 9.7, around central galaxies at the characteristic Schechter function mass, M ⌠M*. We fit the radial profiles of satellite number densities with simple power laws, finding slopes in the range â1.1 to â1.4 for mass-selected satellites, and â1.3 to â1.6 for passive satellites. We confirm the tendency for passive satellites to be preferentially located around passive central galaxies at 3Ï significance and show that it exists to at least z ⌠2. Meanwhile, the quenched fraction of satellites around star-forming galaxies is consistent with field galaxies of equal stellar masses. We find no convincing evidence for a redshift-dependent evolution of these trends. One simple interpretation of these results is that only passive central galaxies occupy an environment that is capable of independently shutting off star formation in satellite galaxies. By examining the satellites of higher stellar mass star-forming galaxies (log(M*/Mâ) > 11), we conclude that the origin of galactic conformity is unlikely to be exclusively due to the host dark matter halo mass. A halo-mass-independent correlation could be established by either formation bias or a more physical connection between central and satellite star formation histories. For the latter, we argue that a star formation (or active galactic nucleus) related outburst event from the central galaxy could establish a hot halo environment which is then capable of quenching both central and satellite galaxie
Star formation in the cluster CLG0218.3-0510 at z=1.62 and its large-scale environment: the infrared perspective
The galaxy cluster CLG0218.3-0510 at z=1.62 is one of the most distant galaxy
clusters known, with a rich muti-wavelength data set that confirms a mature
galaxy population already in place. Using very deep, wide area (20x20 Mpc)
imaging by Spitzer/MIPS at 24um, in conjunction with Herschel 5-band imaging
from 100-500um, we investigate the dust-obscured, star-formation properties in
the cluster and its associated large scale environment. Our galaxy sample of
693 galaxies at z=1.62 detected at 24um (10 spectroscopic and 683 photo-z)
includes both cluster galaxies (i.e. within r <1 Mpc projected clustercentric
radius) and field galaxies, defined as the region beyond a radius of 3 Mpc. The
star-formation rates (SFRs) derived from the measured infrared luminosity range
from 18 to 2500 Ms/yr, with a median of 55 Ms/yr, over the entire radial range
(10 Mpc). The cluster brightest FIR galaxy, taken as the centre of the galaxy
system, is vigorously forming stars at a rate of 25670 Ms/yr, and the
total cluster SFR enclosed in a circle of 1 Mpc is 116196 Ms/yr. We
estimate a dust extinction of about 3 magnitudes by comparing the SFRs derived
from [OII] luminosity with the ones computed from the 24um fluxes. We find that
the in-falling region (1-3 Mpc) is special: there is a significant decrement
(3.5x) of passive relative to star-forming galaxies in this region, and the
total SFR of the galaxies located in this region is lower (130 Ms/yr/Mpc2) than
anywhere in the cluster or field, regardless of their stellar mass. In a
complementary approach we compute the local galaxy density, Sigma5, and find no
trend between SFR and Sigma5. However, we measure an excess of star-forming
galaxies in the cluster relative to the field by a factor 1.7, that lends
support to a reversal of the SF-density relation in CLG0218.Comment: accepted for publication in MNRAS. v2: minor correction
The Halo Mass-Bias Redshift Evolution in the CDM Cosmology
We derive an analytic model for the redshift evolution of linear-bias,
allowing for interactions and merging of the mass-tracers, by solving a second
order differential equation based on linear perturbation theory and the
Friedmann-Lemaitre solutions of the cosmological field equations. We then study
the halo-mass dependence of the bias evolution, using the dark matter halo
distribution in a CDM simulation in order to calibrate the free
parameters of the model. Finally, we compare our theoretical predictions with
available observational data and find a good agreement. In particular, we find
that the bias of optical QSO's evolve differently than those selected in X-rays
and that their corresponding typical dark matter halo mass is and \magcir 5 \times 10^{13} h^{-1} M_{\odot},
respectively.Comment: 8 pages, 5 figures, accepted for publication in Ap
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