3,847 research outputs found

    Sutures and contact homology I

    Full text link
    We define a relative version of contact homology for contact manifolds with convex boundary, and prove basic properties of this relative contact homology. Similar considerations also hold for embedded contact homology

    Fusion of Distance Measurements between Agents with Unknown Correlations

    Full text link
    Cooperative localization is a promising solution to improve the accuracy and overcome the shortcomings of GNSS. Cooperation is often achieved by measuring the distance between users. To optimally integrate a distance measurement between two users into a navigation filter, the correlation between the errors of their estimates must be known. Unfortunately, in large scale networks the agents cannot compute these correlations and must use consistent filters. A consistent filter provides an upper bound on the covariance of the error of the estimator taking into account all the possible correlations. In this paper, a consistent linear filter for integrating a distance measurement is derived using Split Covariance Intersection. Its analysis shows that a distance measurement between two agents can only benefit one of them, i.e., only one of the two can use the distance measurement to improve its estimator. Furthermore, in some cases, none can. A necessary condition for an agent to benefit from the measurement is given for a general class of objective functions. When the objective function is the trace or the determinant, necessary and sufficient conditions are given

    Forces on a boiling bubble in a developing boundary layer, in microgravity with g-jitter and in terrestrial conditions

    Get PDF
    Terrestrial and microgravity flow boiling experiments were carried out with the same test rig, comprising a locally heated artificial cavity in the center of a channel near the frontal edge of an intrusive glass bubble generator. Bubble shapes were in microgravity generally not far from those of truncated spheres,which permitted the computation of inertial lift and drag from potential flow theory for truncated spheres approximating the actual shape. For these bubbles, inertial lift is counteracted by drag and both forces are of the same order of magnitude as g-jitter. A generalization of the Laplace equation is found which applies to a deforming bubble attached to a plane wall and yields the pressure difference between the hydrostatic pressures in the bubble and at the wall, p. A fully independent way to determine the overpressure p is given by a second Euler-Lagrange equation. Relative differences have been found to be about 5% for both terrestrial and microgravity bubbles. A way is found to determine the sum of the two counteracting major force contributions on a bubble in the direction normal to the wall from a single directly measurable quantity. Good agreement with expectation values for terrestrial bubbles was obtained with the difference in radii of curvature averaged over the liquid-vapor interface, (1/R2 − 1/R1), multiplied with the surface tension coefficient, σ. The new analysis methods of force components presented also permit the accounting for a surface tension gradient along the liquid-vapor interface. No such gradients were found for the present measurements

    Mechanisms of Vascular Damage by Hemorrhagic Snake Venom Metalloproteinases: Tissue Distribution and In Situ Hydrolysis

    Get PDF
    Snakebite accidents by vipers cause a massive disturbance in hemostasis and tissue damage at the snakebite area. The systemic effects are often prevented by antivenom therapy. However, the local symptoms are not neutralized by antivenoms and are related to the temporary or permanent disability observed in many patients. Although the mechanisms involved in coagulation or necrotic disturbances induced by snake venoms are well known, the disruption of capillary vessels by SVMPs leading to hemorrhage and consequent local tissue damage is not fully understood. In our study, we reveal the mechanisms involved in hemorrhage induced by SVMPs by comparing the action of high and low hemorrhagic toxins isolated from Bothrops venoms, in mouse skin. We show remarkable differences in the tissue distribution and hydrolysis of collagen within the hemorrhagic lesions induced by high and low hemorrhagic metalloproteinases. According to our data, tissue accumulation of hemorrhagic toxins near blood vessel walls allowing the hydrolysis of basement membrane components, preferably collagen IV. These observations unveil new mechanistic insights supporting the local administration of metalloproteinases inhibitors as an alternative to improve snakebite treatment besides antivenom therapy

    Together Beyond Accession: Turkey as the EU’s Indispensable Partner. College of Europe Policy Brief #15.18, November 2018

    Get PDF
    > Following turbulent years in European Union-Turkey relations, the June 2018 elections in Turkey and the prospective appointment of a new European Commission following the 2019 European Parliament elections provide a window of opportunity to take stock of the deadlock in Turkey’s EU bid. > Incoming European leaders should engage in a profound rethinking of EU-Turkey relations, beyond the accession perspective. > Concretely, the incoming Commission and especially High Representative should push for a renewal of EU strategic engagement with Turkey to ensure ‘togetherness’ in addressing changing geopolitical, economic and security equilibria. This engagement should rely on a four-pillar, multidimensional approach: > Amid growing economic instability in Turkey, we suggest advancing towards an updated Customs Union, while seizing on Turkey’s potential as a central hub in the Southern Energy Corridor. > This strong economic asset could leverage further EU engagement on human rights, rule of law and democracy and enable the Union to adopt innovative measures in support of Turkish civil society. > International developments have positioned Turkey as a crucial, albeit ambivalent, foreign policy partner, especially in the Middle East. For this reason, the EU should promote active foreign policy coordination and cooperation with Turkey. > Migration has been a rare, yet sensitive area of cooperation. In this domain, emphasis should be placed on enhancing the implementation of the 2016 EU-Turkey Statement

    European Portuguese Adaptation of Glasgow Content of Thoughts Inventory (GCTI): Psychometric Characterization in Higher Education Students

    Get PDF
    Persistent cognitive activity is an important factor in disturbing sleep-onset both during bedtime and when attempting to get back to sleep after nocturnal awakenings. One of the most specific self-report measures designed to assess this feature is the Glasgow Content of Thoughts Inventory (GCTI). In this study, we investigated the preliminary psychometric properties of GCTI in a large sample of higher education European Portuguese students (N = 2995). Our results suggest that there is evidence of good internal consistency (α = 0.93) and validity indicators. Moreover, we found an interpretable factorial structure comprising 5 correlated factors that needs to be confirmed in future studies. The European Portuguese version of the GCTI appears to be a reliable and valid instrument for measurement of sleep-onset disturbing cognitions
    • …
    corecore