3,847 research outputs found
Sutures and contact homology I
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
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
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
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
> 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
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
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