1,027 research outputs found
Shedding light on a living lab: the CLEF NEWSREEL open recommendation platform
In the CLEF NEWSREEL lab, participants are invited to evaluate news recommendation techniques in real-time by providing news recommendations to actual users that visit commercial news portals to satisfy their information needs. A central role within this lab is the communication between participants and the users. This is enabled by The Open Recommendation Platform (ORP), a web-based platform which distributes users' impressions of news articles to the participants and returns their recommendations to the readers. In this demo, we illustrate the platform and show how requests are handled to provide relevant news articles in real-time
Detection of curved lines with B-COSFIRE filters: A case study on crack delineation
The detection of curvilinear structures is an important step for various
computer vision applications, ranging from medical image analysis for
segmentation of blood vessels, to remote sensing for the identification of
roads and rivers, and to biometrics and robotics, among others. %The visual
system of the brain has remarkable abilities to detect curvilinear structures
in noisy images. This is a nontrivial task especially for the detection of thin
or incomplete curvilinear structures surrounded with noise. We propose a
general purpose curvilinear structure detector that uses the brain-inspired
trainable B-COSFIRE filters. It consists of four main steps, namely nonlinear
filtering with B-COSFIRE, thinning with non-maximum suppression, hysteresis
thresholding and morphological closing. We demonstrate its effectiveness on a
data set of noisy images with cracked pavements, where we achieve
state-of-the-art results (F-measure=0.865). The proposed method can be employed
in any computer vision methodology that requires the delineation of curvilinear
and elongated structures.Comment: Accepted at Computer Analysis of Images and Patterns (CAIP) 201
The Discovery of a Twelfth Wolf-Rayet Star in the Small Magellanic Cloud
We report the discovery of a relatively faint (V=15.5) early-type WN star in
the SMC. The line strength and width of He II lambda 4686 emission is similar
to that of the other SMC WNs, and the presense of N V lambda 4603,19 emission
(coupled with the lack of N III) suggests this star is of spectral type
WN3-4.5, and thus is similar in type to the other SMC WRs. Also like the other
SMC WN stars, an early-type absorption spectrum is weakly present. The absolute
magnitude is comparable to that of other (single) Galactic early-type WNs. The
star is located in the Hodge 53 OB association, which is also the home of two
other SMC WNs. This star, which we designate SMC-WR12, was actually detected at
a high significance level in an earlier interference-filter survey, but the
wrong star was observed as part of a spectroscopic followup, and this case of
mistaken identity resulted in its Wolf-Rayet nature not being recognized until
now.Comment: Accepted by PASP (November 2003 issue
Biochemical estimation of muscle mass and unbiased assessment of kidney function using serum creatinine and cystatin-C: A prognostic validation study within UK Biobank
Statistical Analysis Plan – A proposal for the biochemical estimation of muscle mass and the unbiased assessment of kidney function using serum creatinine and cystatin-C: A prognostic validation study within UK Biobank
HST observations of the Local Group dwarf galaxy Leo I
We present deep HST F555W (V) and F814W (I) observations of a central field
in the Local Group dwarf spheroidal (dSph) galaxy Leo I. The resulting
color-magnitude diagram (CMD) reaches I \simeq 26 and reveals the oldest ~10-15
Gyr old turnoffs. Nevertheless, a horizontal branch is not obvious in the CMD.
Given the low metallicity of the galaxy, this likely indicates that the first
substantial star formation in the galaxy may have been somehow delayed in Leo I
in comparison with the other dSph satellites of the Milky Way. The subgiant
region is well and uniformly populated from the oldest turnoffs up to the 1 Gyr
old turnoff, indicating that star formation has proceeded in a continuous way,
with possible variations in intensity but no big gaps between successive
bursts, over the galaxy's lifetime. The structure of the red-clump of core
He-burning stars is consistent with the large amount of intermediate-age
population inferred from the main sequence and the subgiant region. In spite of
the lack of gas in Leo I, the CMD clearly shows star formation continuing until
1 Gyr ago and possibly until a few hundred Myrs ago in the central part of the
galaxy.Comment: 26 pages with 8 figures (fig 2 not available electronically). To be
published in ApJ, April 1 1999 (vol.514, #2
Moderate hypothermia within 6 h of birth plus inhaled xenon versus moderate hypothermia alone after birth asphyxia (TOBY-Xe): a proof-of-concept, open-label, randomised controlled trial
Background Moderate cooling after birth asphyxia is associated with substantial reductions in death and disability, but additional therapies might provide further benefit. We assessed whether the addition of xenon gas, a promising novel therapy, after the initiation of hypothermia for birth asphyxia would result in further improvement. Methods Total Body hypothermia plus Xenon (TOBY-Xe) was a proof-of-concept, randomised, open-label, parallel-group trial done at four intensive-care neonatal units in the UK. Eligible infants were 36–43 weeks of gestational age, had signs of moderate to severe encephalopathy and moderately or severely abnormal background activity for at least 30 min or seizures as shown by amplitude-integrated EEG (aEEG), and had one of the following: Apgar score of 5 or less 10 min after birth, continued need for resuscitation 10 min after birth, or acidosis within 1 h of birth. Participants were allocated in a 1:1 ratio by use of a secure web-based computer-generated randomisation sequence within 12 h of birth to cooling to a rectal temperature of 33·5°C for 72 h (standard treatment) or to cooling in combination with 30% inhaled xenon for 24 h started immediately after randomisation. The primary outcomes were reduction in lactate to N-acetyl aspartate ratio in the thalamus and in preserved fractional anisotropy in the posterior limb of the internal capsule, measured with magnetic resonance spectroscopy and MRI, respectively, within 15 days of birth. The investigator assessing these outcomes was masked to allocation. Analysis was by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT00934700, and with ISRCTN, as ISRCTN08886155. Findings The study was done from Jan 31, 2012, to Sept 30, 2014. We enrolled 92 infants, 46 of whom were randomly assigned to cooling only and 46 to xenon plus cooling. 37 infants in the cooling only group and 41 in the cooling plus xenon group underwent magnetic resonance assessments and were included in the analysis of the primary outcomes. We noted no significant differences in lactate to N-acetyl aspartate ratio in the thalamus (geometric mean ratio 1·09, 95% CI 0·90 to 1·32) or fractional anisotropy (mean difference −0·01, 95% CI −0·03 to 0·02) in the posterior limb of the internal capsule between the two groups. Nine infants died in the cooling group and 11 in the xenon group. Two adverse events were reported in the xenon group: subcutaneous fat necrosis and transient desaturation during the MRI. No serious adverse events were recorded. Interpretation Administration of xenon within the delayed timeframe used in this trial is feasible and apparently safe, but is unlikely to enhance the neuroprotective effect of cooling after birth asphyxia
Decoding of the light changes in eclipsing Wolf-Rayet binaries I. A non-classical approach to the solution of light curves
We present a technique to determine the orbital and physical parameters of
eclipsing eccentric Wolf-Rayet + O-star binaries, where one eclipse is produced
by the absorption of the O-star light by the stellar wind of the W-R star. Our
method is based on the use of the empirical moments of the light curve that are
integral transforms evaluated from the observed light curves. The optical depth
along the line of sight and the limb darkening of the W-R star are modelled by
simple mathematical functions, and we derive analytical expressions for the
moments of the light curve as a function of the orbital parameters and the key
parameters of the transparency and limb-darkening functions. These analytical
expressions are then inverted in order to derive the values of the orbital
inclination, the stellar radii, the fractional luminosities, and the parameters
of the wind transparency and limb-darkening laws. The method is applied to the
SMC W-R eclipsing binary HD 5980, a remarkable object that underwent an
LBV-like event in August 1994. The analysis refers to the pre-outburst
observational data. A synthetic light curve based on the elements derived for
the system allows a quality assessment of the results obtained.Comment: Accepted for publication in Astronomy & Astrophysic
Automatic differentiation of u- and n-serrated patterns in direct immunofluorescence images
Epidermolysis bullosa acquisita (EBA) is a subepidermal autoimmune blistering disease of the skin. Manual u- and n-serrated patterns analysis in direct immunofluorescence (DIF) images is used in medical practice to differentiate EBA from other forms of pemphigoid. The manual analysis of serration patterns in DIF images is very challenging, mainly due to noise and lack of training of the immunofluorescence (IF) microscopists. There are no automatic techniques to distinguish these two types of serration patterns. We propose an algorithm for the automatic recognition of such a disease. We first locate a region where u- and n-serrated patterns are typically found. Then, we apply a bank of B-COSFIRE filters to the identified region of interest in the DIF image in order to detect ridge contours. This is followed by the construction of a normalized histogram of orientations. Finally, we classify an image by using the nearest neighbors algorithm that compares its normalized histogram of orientations with all the images in the dataset. The best results that we achieve on the UMCG publicly available data set is 84.6% correct classification, which is comparable to the results of medical experts
A UBVR CCD Survey of the Magellanic Clouds
We present photometry and a preliminary interpretation of a UBVR survey of
the Large and Small Magellanic Clouds. We determine improved values for the
relative number of blue and red supergiants. We also compare the relative
number of Red Supergiants (RSGs) and Wolf-Rayet stars, demonstrating a strong,
tight correlation with metallicity, and reinvestigate the initial mass function
slope of massive stars found in the field.Comment: complete postscript (including embedded figures) can be found at:
ftp://ftp.lowell.edu/pub/massey/mcatlas.ps.gz Accepted for publication in the
ApJ
An Atlas of FUSE Sight Lines Toward the Magellanic Clouds
We present an atlas of 57 Large Magellanic Cloud (LMC) and 37 Small
Magellanic Cloud (SMC) observations obtained with the Far Ultraviolet
Spectroscopic Explorer (FUSE) satellite. The atlas highlights twelve
interstellar absorption line transitions at a resolution of ~15 km/s. These
transitions cover a broad range of temperatures, ionization states, and
abundances. The species included are OVI, which probes hot (T~3x10^5 K) ionized
gas; CIII and FeIII, which probe warm (T~10^4 K) ionized gas; SiII, PII, CII,
FeII, and OI, warm neutral gas; and six different molecular hydrogen
transitions, which trace cold (T<=500 K) gas. We include Schmidt Halpha CCD
images of the region surrounding each sight line showing the morphology of warm
ionized gas in the vicinity, along with continuum images near each FUSE
aperture position. Finally, we present several initial scientific results
derived from this dataset on the interstellar medium of the Magellanic Clouds
and Galactic halo.Comment: 29 pages, 6 figures. Complete Atlas of 94 additional images (~800kB
each) is available at http://fuse.pha.jhu.edu/~danforth/atlas Accepted to the
ApJS March 200
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