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Search Results: 1 - 10 of 461938 matches for " Rehn A "
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A New Species of Roach of the Genus Kakerlac (Loboptera Auct.)From Southern Texas
James A. G. Rehn
Psyche , 1904, DOI: 10.1155/1904/75607
Das gestielte Myom - Zwei besondere Differentialdiagnosen
Rehn A,Hess T
Journal für Fertilit?t und Reproduktion , 2004,
Abstract: Zur pr operativen Abkl rung eines unklaren Unterbauchtumors stehen uns diverse Abkl rungsmethoden zur Verfügung. Trotzdem werden wir intraoperativ immer wieder überrascht. – Fall Nummer 1: 32j hrige Patientin, welche schon seit Jahren wegen bekannter Spondylolisthesis konservativ behandelt wurde. Ein Zufallsbefund im Rahmen der gyn kologischen Jahreskontrolle zeigte eine unklare Raumforderung im Bereich der rechten Adnexe. Sonographisch und in der MRT-Untersuchung wurde der Verdacht auf ein gestieltes Myom ge u ert, intraoperativ fand sich aber ein gro er retroperitonealer Tumor, welcher retrospektiv bereits auf lteren R ntgenbildern zu sehen war. Histologisch handelte es sich um ein Schwannom. – Fall Nummer 2: 46j hrige Patientin mit im Rahmen der gyn kologischen Jahreskontrolle festgestellter Raumforderung parauterin rechts. Pr operativ wurde mittels Ultraschall und Computertomographie die Diagnose eines gestielten Myoms gestellt. Intraoperativ fand sich ein kugeliger Tumor im Omentum majus, welcher histologisch die Diagnose einer leiomyomat sen Neoplasie des Omentum majus ergab. In beiden F llen wurde pr operativ die Diagnose eines gestielten Myoms gestellt, intraoperativ jedoch nicht best tigt. Die Differentialdiagnose des gestielten Myoms ist sehr breit und verlangt unbedingt den Nachweis eines Stiels durch bildgebende Verfahren. Au erdem l t sich anhand der beiden Fallbeispiele zeigen, da wir trotz vieler pr operativer Abkl rungsm glichkeiten nicht vor intraoperativen überraschungen gefeit sind.
Improving adjustments for older age in pre-hospital assessment and care
Rehn Marius
Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine , 2013, DOI: 10.1186/1757-7241-21-4
Abstract: Population estimates projects a significant increase in the geriatric population making elderly trauma patients more common. The geriatric trauma patients experience higher incidence of pre-existing medical conditions, impaired age-dependent physiologic reserve, use potent drugs and suffer from trauma system related shortcomings that influence outcomes. To improve adjustments for older age in pre-hospital assessment and care, several initiatives should be implemented. Decision-makers should make system revisions and introduce advanced point-of-care initiatives to improve outcome after trauma for the elderly.
Random Coulomb antiferromagnets: from diluted spin liquids to Euclidean random matrices
J. Rehn,Arnab Sen,Alexei Andreanov,Kedar Damle,R. Moessner,A. Scardicchio
Physics , 2015, DOI: 10.1103/PhysRevB.92.085144
Abstract: We study a disordered classical Heisenberg magnet with uniformly antiferromagnetic interactions which are frustrated on account of their long-range Coulomb form, {\em i.e.} $J(r)\sim -A\ln r$ in $d=2$ and $J(r)\sim A/r$ in $d=3$. This arises naturally as the $T\rightarrow 0$ limit of the emergent interactions between vacancy-induced degrees of freedom in a class of diluted Coulomb spin liquids (including the classical Heisenberg antiferromagnets on checkerboard, SCGO and pyrochlore lattices) and presents a novel variant of a disordered long-range spin Hamiltonian. Using detailed analytical and numerical studies we establish that this model exhibits a very broad paramagnetic regime that extends to very large values of $A$ in both $d=2$ and $d=3$. In $d=2$, using the lattice-Green function based finite-size regularization of the Coulomb potential (which corresponds naturally to the underlying low-temperature limit of the emergent interactions between orphan-spins), we only find evidence that freezing into a glassy state occurs in the limit of strong coupling, $A=\infty$, while no such transition seems to exist at all in $d=3$. We also demonstrate the presence and importance of screening for such a magnet. We analyse the spectrum of the Euclidean random matrices describing a Gaussian version of this problem, and identify a corresponding quantum mechanical scattering problem.
Analytic Framework for Students' Use of Mathematics in Upper-Division Physics
Bethany R. Wilcox,Marcos D. Caballero,Daniel A. Rehn,Steven J. Pollock
Physics , 2013, DOI: 10.1103/PhysRevSTPER.9.020119
Abstract: Many students in upper-division physics courses struggle with the mathematically sophisticated tools and techniques that are required for advanced physics content. We have developed an analytical framework to assist instructors and researchers in characterizing students' difficulties with specific mathematical tools when solving the long and complex problems that are characteristic of upper-division. In this paper, we present this framework, including its motivation and development. We also describe an application of the framework to investigations of student difficulties with direct integration in electricity and magnetism (i.e., Coulomb's Law) and approximation methods in classical mechanics (i.e., Taylor series). These investigations provide examples of the types of difficulties encountered by advanced physics students, as well as the utility of the framework for both researchers and instructors.
Optimal Replica Placement in Tree Networks with QoS and Bandwidth Constraints and the Closest Allocation Policy
Veronika Rehn-Sonigo
Computer Science , 2007,
Abstract: This paper deals with the replica placement problem on fully homogeneous tree networks known as the Replica Placement optimization problem. The client requests are known beforehand, while the number and location of the servers are to be determined. We investigate the latter problem using the Closest access policy when adding QoS and bandwidth constraints. We propose an optimal algorithm in two passes using dynamic programming.
Exploiting Symmetry in Integer Convex Optimization using Core Points
Katrin Herr,Thomas Rehn,Achill Schürmann
Mathematics , 2012, DOI: 10.1016/j.orl.2013.02.007
Abstract: We consider convex programming problems with integrality constraints that are invariant under a linear symmetry group. To decompose such problems we introduce the new concept of core points, i.e., integral points whose orbit polytopes are lattice-free. For symmetric integer linear programs we describe two algorithms based on this decomposition. Using a characterization of core points for direct products of symmetric groups, we show that prototype implementations can compete with state-of-the-art commercial solvers, and solve an open MIPLIB problem.
On Lattice-Free Orbit Polytopes
Katrin Herr,Thomas Rehn,Achill Schürmann
Mathematics , 2014, DOI: 10.1007/s00454-014-9638-x
Abstract: Given a permutation group acting on coordinates of $\mathbb{R}^n$, we consider lattice-free polytopes that are the convex hull of an orbit of one integral vector. The vertices of such polytopes are called \emph{core points} and they play a key role in a recent approach to exploit symmetry in integer convex optimization problems. Here, naturally the question arises, for which groups the number of core points is finite up to translations by vectors fixed by the group. In this paper we consider transitive permutation groups and prove this type of finiteness for the $2$-homogeneous ones. We provide tools for practical computations of core points and obtain a complete list of representatives for all $2$-homogeneous groups up to degree twelve. For transitive groups that are not $2$-homogeneous we conjecture that there exist infinitely many core points up to translations by the all-ones-vector. We prove our conjecture for two large classes of groups: For imprimitive groups and groups that have an irrational invariant subspace.
Strategies for Replica Placement in Tree Networks
Yves Robert,Anne Benoit,Veronika Rehn
Computer Science , 2006,
Abstract: In this paper, we discuss and compare several policies to place replicas in tree networks, subject to server capacity and QoS constraints. The client requests are known beforehand, while the number and location of the servers are to be determined. The standard approach in the literature is to enforce that all requests of a client be served by the closest server in the tree. We introduce and study two new policies. In the first policy, all requests from a given client are still processed by the same server, but this server can be located anywhere in the path from the client to the root. In the second policy, the requests of a given client can be processed by multiple servers. One major contribution of this paper is to assess the impact of these new policies on the total replication cost. Another important goal is to assess the impact of server heterogeneity, both from a theoretical and a practical perspective. In this paper, we establish several new complexity results, and provide several efficient polynomial heuristics for NP-complete instances of the problem. These heuristics are compared to an absolute lower bound provided by the formulation of the problem in terms of the solution of an integer linear program.
Isolation, morphological identification and pathogenicity of Cylindrocladium scoparium and C. clavatum isolates obtained from plants rhizosphere cultivated in Pernambuco State
Rehn, Vitorina Nerivania Covello;Menezes, Maria;Rehn, Kurt Georg;Coêlho, Rildo Sartori Barbosa;
Brazilian Journal of Microbiology , 2004, DOI: 10.1590/S1517-83822004000300004
Abstract: twelve isolates of cylindrocladium scoparium and 4 isolates of c. clavatum were obtained from the rhizosphere of various species of plants by baiting with ricinus communis leaves. the isolates of c. scoparium developed conidia of 32-(45)-60 x 3 -(4)-5 μm, and pyriform to ellipsoidal vesicles. c. clavatum showed conidia of 36-(44)-49 x 2-(4)-6 μm and clavate vesicles. all isolates induced necrosis on leaves and hypocotyls of eucalypt seedlings, with varying expression of symptoms.
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