4,466 research outputs found

    Statistical data mining for symbol associations in genomic databases

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    A methodology is proposed to automatically detect significant symbol associations in genomic databases. A new statistical test is proposed to assess the significance of a group of symbols when found in several genesets of a given database. Applied to symbol pairs, the thresholded p-values of the test define a graph structure on the set of symbols. The cliques of that graph are significant symbol associations, linked to a set of genesets where they can be found. The method can be applied to any database, and is illustrated MSigDB C2 database. Many of the symbol associations detected in C2 or in non-specific selections did correspond to already known interactions. On more specific selections of C2, many previously unkown symbol associations have been detected. These associations unveal new candidates for gene or protein interactions, needing further investigation for biological evidence

    Guiding the surgical gesture using an electro-tactile stimulus array on the tongue: A feasibility study

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    Under conventional "open-" surgery, the physician has to take care of the patient, interact with other clinicians and check several monitoring devices. Nowadays, the Computer Assisted Surgery proposes to integrate 3D cameras in the operating theatre in order to assist the surgeon in performing minimal-invasive surgical punctures. The cameras localize the needle and the computer guides the surgeon towards an intracorporeal clinically-defined target. A visualization system (screen) is employed to provide the surgeon with indirect visual spatial information about the intracorporeal positions of the needle. The present work proposes to use another sensory modality to guide the surgeon thus keeping the visual modality fully dedicated to the surgical gesture. For this, the sensory substitution paradigm using the Bach-y-Rita's "Tongue Display Unit" (TDU) is exploited to provide to the surgeon information of the position tool. The TDU device is composed of a 6x6 matrix of electrodes transmitting electrotactile information on the tongue surface. The underlying idea consists in transmitting information about the deviation of the needle movement with regard to a pre-planned "optimal" trajectory. We present an experiment assessing the guidance effectiveness of an intracorporeal puncture under TDU guidance with respect to the performance evidenced under a usual visual guidance system

    Nemo: an evolutionary and population genetics programming framework

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    Summary: Nemo is an individual-based, genetically explicit and stochastic population computer program for the simulation of population genetics and life-history trait evolution in a metapopulation context. It comes as both a C++ programming framework and an executable program file. Its object-oriented programming design gives it the flexibility and extensibility needed to implement a large variety of forward-time evolutionary models. It provides developers with abstract models allowing them to implement their own life-history traits and life-cycle events. Nemo offers a large panel of population models, from the Island model to lattice models with demographic or environmental stochasticity and a variety of already implemented traits (deleterious mutations, neutral markers and more), life-cycle events (mating, dispersal, aging, selection, etc.) and output operators for saving data and statistics. It runs on all major computer platforms including parallel computing environments. Availability: The source code, binaries and documentation are available under the GNU General Public License at . Contact: [email protected]

    Simultaneous growth of two cancer cell lines evidences variability in growth rates

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    Cancer cells co-cultured in vitro reveal unexpected differential growth rates that classical exponential growth models cannot account for. Two non-interacting cell lines were grown in the same culture, and counts of each species were recorded at periodic times. The relative growth of population ratios was found to depend on the initial proportion, in contradiction with the traditional exponential growth model. The proposed explanation is the variability of growth rates for clones inside the same cell line. This leads to a log-quadratic growth model that provides both a theoretical explanation to the phenomenon that was observed, and a better fit to our growth data

    Partage du risque dans l’Union européenne:Expériences interrégionales et internationales

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    Quelle pourrait être la portée du partage du risque macroéconomique entre pays, dans l’Union monétaire européenne, face aux chocs asymétriques ? Pour tenter de répondre à cette question, essentielle par ses implications quant à la stabilité de la construction monétaire européenne, on cherche à estimer l’ampleur de la répartition du risque qui prévaut entre les régions d’un même pays, mais également entre différents pays. On en déduit alors plusieurs leçons pour l’Union monétaire. Ce sujet est exploré à partir d’un travail empirique effectué sur des données régionales, pour les États-Unis et le Canada, ainsi que sur des données nationales se rapportant à un échantillon de 23 pays de l’OCDE, qui comprend les 15 membres de l’Union européenne. Nous procédons à l’aide de notre version modifiée du modèle fondateur de Asdrubali, Sørensen et Yosha (1996), dont nous rappelons les principes. Nous mettons alors en évidence plusieurs résultats concordants du modèle révisé, qui prouvent que, même si l’abandon de la politique monétaire réduit la capacité théorique des membres de l’UE de lisser les chocs asymétriques via la politique macroéconomique, le nouveau régime dans lequel nous sommes entrés, qui génère une plus forte intégration économique, pourrait bien favoriser considérablement le lissage des chocs au travers des mécanismes de marché

    Cirkadijalni ritam, disanje i ponašanje hipogejskih i epigejskih repaša

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    Comparisons of circadian rhythmicity, behavior, and metabolism between surface and cavedwelling salamanders enable elucidation of evolutionary trends in these processes. The obligate cave-dwelling proteid Proteus anguinus did not show any apparent daily rhythm of activity or resting metabolic rate. In contrast, the surface-dwelling salamandrid Euproctus asper had a circadian SMR and activity cycle. These circadian rhythms possessed an endogenous component. The lives of both salamanders studied were characterized by long periods of inactivity punctuated by bouts of foraging or exploratory/predatory behavior. Proteus anguinus had reduced resting metabolic and spontaneous activity rates (considerably lower than most surface-dwelling amphibians), and therefore appears to be a good example of a vertebrate as a low-energy system. The low metabolic and activity rates of P. anguinus are interpreted as adaptations to a subterranean existence where poor and discontinuous food supplies and/or intermittent hypoxia may be present for long periods.Usporedbe cirkadijalnog ritma, ponašanja i metabolizma kod površinskih i špiljskih proteida omogućuju rasvjetljavanje evolucijskih trendova u tim procesima. Obligatorni stanovnik špilja, proteid Proteus anguinus, nije pokazivao nikakav vidljiv dnevni ritam aktivnosti ili posebni metabolizam prilikom odmora. Naprotiv, salamandrid Euproctus asper koji boravi na površini, imao je cirkadijalni SMR i ciklus aktivnosti. Ti cirkadijalni ritmovi imali su endogenu komponentu. Životi obaju proučavanih životinja bili su karakterizirani dugim periodima neaktivnosti, prekidanih hranjenjem ili izviđačkim/predatorskim ponašanjem. Proteus anguinus imala je smanjen metabolizam tijekom odmaranja i tijekom spontane aktivnosti (znatno niži od većine površinskih vodozemaca), pa se čini dobrim primjerom kralježnjaka kao niskoenergetskog sustava. Niske vrijednosti metabolizma i aktivnosti P. anguinus interpretiraju se kao prilagodbe na život u podzemlju, gdje je u duljim periodima prisutna slaba i nekontinuirana opskrba hranom i/ili hipoksija

    Ductile tearing of 2024 aluminum alloy panels

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    International audienceTwo 2024 aluminum alloys are studied. Their second phase volume fraction differ as well as their mean inter-particle ....
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