691 research outputs found
Enumerating Isolated Cliques in Temporal Networks
Isolation is a concept from the world of clique enumeration that is mostly
used to model communities that do not have much contact to the outside world.
Herein, a clique is considered isolated if it has few edges connecting it to
the rest of the graph. Motivated by recent work on enumerating cliques in
temporal networks, we lift the isolation concept to this setting. We discover
that the addition of the time dimension leads to six distinct natural isolation
concepts. Our main contribution is the development of fixed-parameter
enumeration algorithms for five of these six clique types employing the
parameter "degree of isolation". On the empirical side, we implement and test
these algorithms on (temporal) social network data, obtaining encouraging
preliminary results
Document image segmentation using a multiresolution approach. Accurate text line extraction
An overall scheme and related algorithms performing accurate text lines extraction
from an image of document are described in this paper The type of documents
concerned here is very complex, with totally unconstrained data . Postal objects,
especially the so-calledfiatobjects, i.e. : large envelopes, magazines, . . . are within
this kind of documents. Three main phases have been considered to achieve the
overall function . First of all, areas of interest are located using a multiresolution
approach allowing to preserve from large variability of text features . This is
performed directly on the gray-level image . A binarization stage, taking advantage
of the results of the localization, is next performed to extract the lines . At last,
a post-segmentation involving the located areas in the gray-level images and
structural features extracted from the lines allows to deal with severe cases such
as overlapping lines induced by handwritten texts . Examples related to text line
extraction on postal objects are illustrating this paper.Cet article présente une méthodologie et des outils de traitement permettant de localiser puis d'extraire précisément les lignes de texte contenues dans l'image d'un document. La classe des documents visés est de type document très complexe, leurs contenus étant totalement non contraints. Globalement la méthodologie s'articule autour de trois étapes clés. La première est une localisation des zones d'intérêt. Elle est réalisée directement sur l'image en niveaux de gris et utilise une approche multirésolution garantissant une grande robustesse vis-à-vis de la très forte variabilité des textes: taille, disposition, présentation. Une étape de binarisation réalisée séparément pour chaque zone d'intérêt permet dans une seconde phase l'extraction proprement dite des lignes de texte. Enfin, une post-segmentation faisant coopérer la localisation initiale et des caractéristiques structurelles extraites de la ligne permet de traiter les cas très perturbants pour la lecture du chevauchement de lignes sur de l'écriture manuscrite. Des exemples relevant de la problématique de l'extraction des lignes du bloc adresse sur objets postaux (grandes lettres, magazines) illustrent cet article
Time to Virological Failure of 3 Classes of Antiretrovirals after Initiation of Highly Active Antiretroviral Therapy: Results from the EuroSIDA Study Group
Objective. The purpose of the present study was to determine the prevalence and incidence of virological triple drug-class failure (TCF) and to summarize the clinical outcome for patients who started receiving highly active antiretroviral therapy (HAART). Methods. The present study is an observational longitudinal study of 3496 treatment-experienced (TE) and treatment-naive (TN) patients monitored from the time they started receiving HAART (baseline) until TCF occurred (as determined on the basis of viral loads), until AIDS was newly diagnosed, or until death. Results. Four hundred forty-five patients (12.7%) had TCF; 370 (16.6%) of 2230 patients were TE, and 75 (5.9%) of 1266 patients were TN. At 6 years after starting HAART, 21.4% of TE and 11.2% of TN patients had TCF (P < .0001). The prevalence of TCF at or after 2002 was 15.5% in TE patients and 4.8% in TN patients. TN patients had a 32% annual increase in the incidence of TCF (95% confidence interval [CI], 14%-54%; P < .0001); at 5 years after starting HAART, the rate was comparable for TE and TN patients (3.3 and 3.4 cases/100 person-years of follow-up [PYFU], respectively). The incidence of new cases of AIDS or death was 2.7 cases/100 PYFU in patients who did not experience TCF and 5.0 cases/100 PYFU in patients who did experience TCF, an estimated 36% increase with each category of TCF (95% CI, 19%-56%; P < .0001). Conclusion. The prevalence of TCF was low after patients started receiving HAART, particularly among TN patients. Despite the influx of patients who had started receiving HAART more recently, the prevalence of TCF increased over calendar time. Patients with TCF had a higher incidence of newly diagnosed AIDS or death. Treatment of patients with TCF deserves further investigatio
Resolving Stellar Populations outside the Local Group: MAD observations of UKS2323-326
We present a study aimed at deriving constraints on star formation at
intermediate ages from the evolved stellar populations in the dwarf irregular
galaxy UKS2323-326. These observations were also intended to demonstrate the
scientific capabilities of the multi-conjugated adaptive optics demonstrator
(MAD) implemented at the ESO Very Large Telescope as a test-bench of adaptive
optics (AO) techniques. We perform accurate, deep photometry of the field using
J and Ks band AO images of the central region of the galaxy. The near-infrared
(IR) colour-magnitude diagrams clearly show the sequences of asymptotic giant
branch (AGB) stars, red supergiants, and red giant branch (RGB) stars down to
~1 mag below the RGB tip. Optical-near-IR diagrams, obtained by combining our
data with Hubble Space Telescope observations, provide the best separation of
stars in the various evolutionary stages. The counts of AGB stars brighter than
the RGB tip allow us to estimate the star formation at intermediate ages.
Assuming a Salpeter initial mass function, we find that the star formation
episode at intermediate ages produced ~6x10^5 M_sun of stars in the observed
region.Comment: 4 pages, 4 figures, Accepted for publication in A&A Letter
Elaboration of a Novel Design Pirani Pressure Sensor for High Dynamic Range Operation and Fast Response Time
AbstractWe report a novel design for realizing Pirani sensor with a working range from a 1kPa up to pressure over than atmospheric one. The sensor is specifically designed to achieve high sensitivity, fast response time and high robustness. The proof of concept is composed of four metallic resistors interconnected to form a Wheatstone bridge. Two of them act simultaneously as the heating and sensing elements and the two others are used as a temperature reference. The heating element consists of a metallic wire of platinum Pt (3μm width, 1mm length) maintained on each lateral side by periodic silicon oxide SiO2 micro-bridges. The sensor design, fabrication technologies, electrical characterizations and voltage-pressure responses are described and shown. A future perspective is given, which describe the extension of this concept to elastic wave transduction of pressure using a combination of heater element and thin plate elastic waveguide
Grey and white matter correlates of recent and remote autobiographical memory retrieval:Insights from the dementias
The capacity to remember self-referential past events relies on the integrity of a distributed neural network. Controversy exists, however, regarding the involvement of specific brain structures for the retrieval of recently experienced versus more distant events. Here, we explored how characteristic patterns of atrophy in neurodegenerative disorders differentially disrupt remote versus recent autobiographical memory. Eleven behavioural-variant frontotemporal dementia, 10 semantic dementia, 15 Alzheimer's disease patients and 14 healthy older Controls completed the Autobiographical Interview. All patient groups displayed significant remote memory impairments relative to Controls. Similarly, recent period retrieval was significantly compromised in behavioural-variant frontotemporal dementia and Alzheimer's disease, yet semantic dementia patients scored in line with Controls. Voxel-based morphometry and diffusion tensor imaging analyses, for all participants combined, were conducted to investigate grey and white matter correlates of remote and recent autobiographical memory retrieval. Neural correlates common to both recent and remote time periods were identified, including the hippocampus, medial prefrontal, and frontopolar cortices, and the forceps minor and left hippocampal portion of the cingulum bundle. Regions exclusively implicated in each time period were also identified. The integrity of the anterior temporal cortices was related to the retrieval of remote memories, whereas the posterior cingulate cortex emerged as a structure significantly associated with recent autobiographical memory retrieval. This study represents the first investigation of the grey and white matter correlates of remote and recent autobiographical memory retrieval in neurodegenerative disorders. Our findings demonstrate the importance of core brain structures, including the medial prefrontal cortex and hippocampus, irrespective of time period, and point towards the contribution of discrete regions in mediating successful retrieval of distant versus recently experienced events
- …