178 research outputs found

    The Mariner Venus 67 magnetic field control program

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    Mariner 5 magnetic field control progra

    Visual Outcome after Intravitreal Anti-VEGF Therapy for Macular Neovascularisation Secondary to Sorsby's Fundus Dystrophy: A Systematic Review.

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    The aim of this paper is to summarise our own and to review published experience regarding the long-term outcome of intravitreal treatment for macular neovascularisation (MNV) secondary to Sorsby's fundus dystrophy (SFD). A systematic literature search using the MeSH terms [Sorsby] and [anti-vascular endothelial growth factor (VEGF)] was conducted in NCBI/PubMed, Cochrane Central Register of Controlled Trials (CENTRAL), ScienceDirect, Google Scholar and ClinicalTrials.gov to identify publications reporting anti-VEGF treatment outcomes in SFD. Treatment outcomes were extracted for this meta-analysis from 14 publications and an own patient reporting a total of 31 cases with a mean follow-up (FU) of 54 months. Both eyes were affected in ten (32.3%) instances. Heterogenous reporting limited the comparability of the outcomes. All papers in common, however, reported satisfied to excellent responses to anti-VEGF therapy if patients were diagnosed and treated immediately after onset of symptoms. Of 20 eyes, for which visual acuity was reported before and after treatment, five worsened and seven improved by more than 1 line, whereas eight eyes maintained their function by end of the follow up, and 11 eyes (55%) maintained a driving vision (Snellen VA ≥ 0.5). Of six eyes with a VA < 0.5, VA improved in one to VA ≥ 0.5, whereas of 14 eyes with an initial VA ≥ 0.5, this dropped to <0.5 despite therapy. In MNV secondary to SFD, the delay between first symptoms and access to anti-VEGF treatment determines subretinal scar formation and thereby, functional prognosis. If treated early, this is generally favourable under regular controls and a consequent anti-VEGF treatment of MNV activity

    Therapeutic Considerations Related to Finasteride Administration in Male Androgenic Alopecia and Benign Prostatic Hyperplasia

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    Finasteride has been used extensively until now as a relative efficient therapeutic option for male androgenic alopecia and benign prostatic hyperplasia. Unfortunately, over time several concerns appeared regarding the frequency and magnitude of adverse effects, which in some cases have been even irreversible. Herein we review the recent literature on this topic, trying to clarify the current safety profile of Finasteride for these two therapeutic indications. We concluded that Finasteride could be retained as a therapeutic approach for male androgenic alopecia, based on two important reasons. First, a synergistic action between a partial inhibitor of 5α-reductase (Finasteride) and another compound (like Minoxidil) are preferable to a complete suppression of 5α-reductase (see Dutasteride), in order to preserve the important physiological roles of dihydrotestosterone. Second, Finasteride side effects can currently be addressed in part prior to the onset of the therapy, by using information about the patient such as hand preference and sexual orientation to predict the risk of adverse effects

    Prolongations of Geometric Overdetermined Systems

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    We show that a wide class of geometrically defined overdetermined semilinear partial differential equations may be explicitly prolonged to obtain closed systems. As a consequence, in the case of linear equations we extract sharp bounds on the dimension of the solution space.Comment: 22 pages. In the second version, a comparison with the classical theory of prolongations was added. In this third version more details were added concerning our construction and especially the use of Kostant's computation of Lie algebra cohomolog

    Rendezvous of Distance-aware Mobile Agents in Unknown Graphs

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    We study the problem of rendezvous of two mobile agents starting at distinct locations in an unknown graph. The agents have distinct labels and walk in synchronous steps. However the graph is unlabelled and the agents have no means of marking the nodes of the graph and cannot communicate with or see each other until they meet at a node. When the graph is very large we want the time to rendezvous to be independent of the graph size and to depend only on the initial distance between the agents and some local parameters such as the degree of the vertices, and the size of the agent's label. It is well known that even for simple graphs of degree Δ\Delta, the rendezvous time can be exponential in Δ\Delta in the worst case. In this paper, we introduce a new version of the rendezvous problem where the agents are equipped with a device that measures its distance to the other agent after every step. We show that these \emph{distance-aware} agents are able to rendezvous in any unknown graph, in time polynomial in all the local parameters such the degree of the nodes, the initial distance DD and the size of the smaller of the two agent labels l=min(l1,l2)l = \min(l_1, l_2). Our algorithm has a time complexity of O(Δ(D+logl))O(\Delta(D+\log{l})) and we show an almost matching lower bound of Ω(Δ(D+logl/logΔ))\Omega(\Delta(D+\log{l}/\log{\Delta})) on the time complexity of any rendezvous algorithm in our scenario. Further, this lower bound extends existing lower bounds for the general rendezvous problem without distance awareness

    Differential Calculi on Some Quantum Prehomogeneous Vector Spaces

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    This paper is devoted to study of differential calculi over quadratic algebras, which arise in the theory of quantum bounded symmetric domains. We prove that in the quantum case dimensions of the homogeneous components of the graded vector spaces of k-forms are the same as in the classical case. This result is well-known for quantum matrices. The quadratic algebras, which we consider in the present paper, are q-analogues of the polynomial algebras on prehomogeneous vector spaces of commutative parabolic type. This enables us to prove that the de Rham complex is isomorphic to the dual of a quantum analogue of the generalized Bernstein-Gelfand-Gelfand resolution.Comment: LaTeX2e, 51 pages; changed conten

    Two dimensional Sen connections and quasi-local energy-momentum

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    The recently constructed two dimensional Sen connection is applied in the problem of quasi-local energy-momentum in general relativity. First it is shown that, because of one of the two 2 dimensional Sen--Witten identities, Penrose's quasi-local charge integral can be expressed as a Nester--Witten integral.Then, to find the appropriate spinor propagation laws to the Nester--Witten integral, all the possible first order linear differential operators that can be constructed only from the irreducible chiral parts of the Sen operator alone are determined and examined. It is only the holomorphy or anti-holomorphy operator that can define acceptable propagation laws. The 2 dimensional Sen connection thus naturally defines a quasi-local energy-momentum, which is precisely that of Dougan and Mason. Then provided the dominant energy condition holds and the 2-sphere S is convex we show that the next statements are equivalent: i. the quasi-local mass (energy-momentum) associated with S is zero; ii.the Cauchy development D(Σ)D(\Sigma) is a pp-wave geometry with pure radiation (D(Σ)D(\Sigma) is flat), where Σ\Sigma is a spacelike hypersurface whose boundary is S; iii. there exist a Sen--constant spinor field (two spinor fields) on S. Thus the pp-wave Cauchy developments can be characterized by the geometry of a two rather than a three dimensional submanifold.Comment: 20 pages, Plain Tex, I

    Quantisation of twistor theory by cocycle twist

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    We present the main ingredients of twistor theory leading up to and including the Penrose-Ward transform in a coordinate algebra form which we can then `quantise' by means of a functorial cocycle twist. The quantum algebras for the conformal group, twistor space CP^3, compactified Minkowski space CMh and the twistor correspondence space are obtained along with their canonical quantum differential calculi, both in a local form and in a global *-algebra formulation which even in the classical commutative case provides a useful alternative to the formulation in terms of projective varieties. We outline how the Penrose-Ward transform then quantises. As an example, we show that the pull-back of the tautological bundle on CMh pulls back to the basic instanton on S^4\subset CMh and that this observation quantises to obtain the Connes-Landi instanton on \theta-deformed S^4 as the pull-back of the tautological bundle on our \theta-deformed CMh. We likewise quantise the fibration CP^3--> S^4 and use it to construct the bundle on \theta-deformed CP^3 that maps over under the transform to the \theta-deformed instanton.Comment: 68 pages 0 figures. Significant revision now has detailed formulae for classical and quantum CP^

    Therapeutic Considerations Related to Finasteride Administration in Male Androgenic Alopecia and Benign Prostatic Hyperplasia

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    Finasteride has been used extensively until now as a relative efficient therapeutic option for male androgenic alopecia and benign prostatic hyperplasia. Unfortunately, over time several concerns appeared regarding the frequency and magnitude of adverse effects, which in some cases have been even irreversible. Herein we review the recent literature on this topic, trying to clarify the current safety profile of Finasteride for these two therapeutic indications. We concluded that Finasteride could be retained as a therapeutic approach for male androgenic alopecia, based on two important reasons. First, a synergistic action between a partial inhibitor of 5α-reductase (Finasteride) and another compound (like Minoxidil) are preferable to a complete suppression of 5α-reductase (see Dutasteride), in order to preserve the important physiological roles of dihydrotestosterone. Second, Finasteride side effects can currently be addressed in part prior to the onset of the therapy, by using information about the patient such as hand preference and sexual orientation to predict the risk of adverse effects

    Almost optimal asynchronous rendezvous in infinite multidimensional grids

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    Two anonymous mobile agents (robots) moving in an asynchronous manner have to meet in an infinite grid of dimension δ&gt; 0, starting from two arbitrary positions at distance at most d. Since the problem is clearly infeasible in such general setting, we assume that the grid is embedded in a δ-dimensional Euclidean space and that each agent knows the Cartesian coordinates of its own initial position (but not the one of the other agent). We design an algorithm permitting the agents to meet after traversing a trajectory of length O(d δ polylog d). This bound for the case of 2d-grids subsumes the main result of [12]. The algorithm is almost optimal, since the Ω(d δ) lower bound is straightforward. Further, we apply our rendezvous method to the following network design problem. The ports of the δ-dimensional grid have to be set such that two anonymous agents starting at distance at most d from each other will always meet, moving in an asynchronous manner, after traversing a O(d δ polylog d) length trajectory. We can also apply our method to a version of the geometric rendezvous problem. Two anonymous agents move asynchronously in the δ-dimensional Euclidean space. The agents have the radii of visibility of r1 and r2, respectively. Each agent knows only its own initial position and its own radius of visibility. The agents meet when one agent is visible to the other one. We propose an algorithm designing the trajectory of each agent, so that they always meet after traveling a total distance of O( ( d)), where r = min(r1, r2) and for r ≥ 1. r)δpolylog ( d r
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