1,521 research outputs found

    Bifurcations of nontrivial solutions of a cubic Helmholtz system

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    This paper presents local and global bifurcation results for radially symmetric solutions of the cubic Helmholtz system \begin{equation*} \begin{cases} -\Delta u - \mu u = \left( u^2 + b \: v^2 \right) u &\text{ on } \mathbb{R}^3, \\ -\Delta v - \nu v = \left( v^2 + b \: u^2 \right) v &\text{ on } \mathbb{R}^3. \end{cases} \end{equation*} It is shown that every point along any given branch of radial semitrivial solutions (u0,0,b)(u_0, 0, b) or diagonal solutions (ub,ub,b)(u_b, u_b, b) (for μ=ν\mu = \nu) is a bifurcation point. Our analysis is based on a detailed investigation of the oscillatory behavior of solutions at infinity that are shown to decay like 1x\frac{1}{|x|} as x|x|\to\infty.Comment: 31 page

    Dual Variational Methods for a nonlinear Helmholtz system

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    This paper considers a pair of coupled nonlinear Helmholtz equations \begin{align*} -\Delta u - \mu u = a(x) \left( |u|^\frac{p}{2} + b(x) |v|^\frac{p}{2} \right)|u|^{\frac{p}{2} - 2}u, \end{align*} \begin{align*} -\Delta v - \nu v = a(x) \left( |v|^\frac{p}{2} + b(x) |u|^\frac{p}{2} \right)|v|^{\frac{p}{2} - 2}v \end{align*} on RN\mathbb{R}^N where 2(N+1)N1<p<2\frac{2(N+1)}{N-1} < p < 2^\ast. The existence of nontrivial strong solutions in W2,p(RN)W^{2, p}(\mathbb{R}^N) is established using dual variational methods. The focus lies on necessary and sufficient conditions on the parameters deciding whether or not both components of such solutions are nontrivial.Comment: Published version. Contains minor revisions: Quote added, explanations on p.12 concerning F_{\mu\nu} = \infty, correction of exponent on p.1

    Die Perzeption Brasiliens durch deutsche Reisende des 19. Jahrhunderts : Maximilian Prinz Wied zu Neuwied und Johann Moritz Rugendas

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    This article focuses the expeditions of Maximilian Prinz Wied zu Neuwied and Johann Moritz Rugendas to Brazil. It discusses initially basic aspects of perception from the early colonial period up to the 19th century. It will then analyze the pictorial characterization of Brazil by both travelers and the reception of their work in Europ

    Macunaíma : eine Rhapsodie

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    During the first decades of the 20th century emerges a Brazilian artistic movement that aims to break with the cultural models imported from Europe. As a landmark one may cite the Week of Modern Art in São Paulo and Mário de Andrade as one of its main figures. His novel Macunaíma stands for one of the central pieces of modern Brazilian literature and was considered by Andrade as a literary rhapsody. This article aims to compare the formal elements of the rhapsody with the actual text written in 1928

    Little Steps Towards Big Goals. Using Linked Data to Develop Next Generation Spatial Data Infrastructures (aka SDI 3.0)

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    Ponencias, comunicaciones y pósters presentados en el 17th AGILE Conference on Geographic Information Science "Connecting a Digital Europe through Location and Place", celebrado en la Universitat Jaume I del 3 al 6 de junio de 2014.Society is moving at an increasing pace toward the next stage of the information society through linked data. Among the relevant developments in geographic information science, linked data approaches offer potential for improving SDI functionality [12]. Linked data uses Semantic Web technologies and makes it possible to link at a very granular level data resources of the web for a multitude of purposes. While the technological implementation in many ways is still in a phase of adolescence, vast amounts of data, including geographic information (GI) have been prepared, for example by the UK Ordinance Survey [8] and other governmental and non-governmental bodies. The overwhelming focus has been on producing RDF formatted data for linked data applications--the foundation for applications. In this short paper, we provide an overview of potentials of linked open data for SDI 3.0 developments. Through two exemplary use cases we illustrate specifically some first steps towards a more web-oriented and distributed approach to creating SDI architectures. The cases demonstrate applications based on the LOD4WFS Adapter, which opens the way for multi-perspective GI applications, created on-demand from multiple GI data resources. These applications automate geometry-based selections of data using spatial queries with the use of RCC8 and OGC Simple Features topological functions. Future work in this area includes adding semantic operators to refine GI processing with multiple ontologies

    Produktionsstandort Bundesrepublik

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    Primate modularity and evolution: first anatomical network analysis of primate head and neck musculoskeletal system

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    Network theory is increasingly being used to study morphological modularity and integration. Anatomical network analysis (AnNA) is a framework for quantitatively characterizing the topological organization of anatomical structures and providing an operational way to compare structural integration and modularity. Here we apply AnNA for the first time to study the macroevolution of the musculoskeletal system of the head and neck in primates and their closest living relatives, paying special attention to the evolution of structures associated with facial and vocal communication. We show that well-defined left and right facial modules are plesiomorphic for primates, while anthropoids consistently have asymmetrical facial modules that include structures of both sides, a change likely related to the ability to display more complex, asymmetrical facial expressions. However, no clear trends in network organization were found regarding the evolution of structures related to speech. Remarkably, the increase in the number of head and neck muscles – and thus of musculoskeletal structures – in human evolution led to a decrease in network density and complexity in humans
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