Isotopic Equivalence from Bezier Curve Subdivision

We prove that the control polygon of a Bezier curve B becomes homeomorphic and ambient isotopic to B via subdivision, and we provide closed-form formulas to compute the number of iterations to ensure these topological characteristics. We first show that the exterior angles of control polygons converge exponentially to zero under subdivision.Comment: arXiv admin note: substantial text overlap with arXiv:1211.035

Entwicklungsszenarien einer alpinen Aue bei einem natürlichen Geschiebedefizit : die Triftaue im Oberhasli

In der zweiten Hälfte des 20. Jahrhunderts hat sich im Zuge des Gletscherrückzugs eine alpine Aue im Triftgebiet gebildet. Zu Beginn prägten dynamische Geschiebeumlagerungsprozesse die Flusslandschaft am Triftwasser und führten zu einer typischen Sukzession einer alpinen Aue. Mit dem weiteren Rückzug des Triftgletschers hat sich Anfang dieses Jahrhunderts der natürliche Triftsee gebildet, der einen Geschiebeeintrag in die darunterliegende Triftaue praktisch vollständig unterbindet. Damit wird die Geschiebedynamik im Triftwasser auf ein absolutes Minimum reduziert. Daher ist es dem Gewässer so gut wie nicht mehr möglich, seinen Verlauf im Zuge von Hochwasserereignissen zu verändern und neue morphologische Strukturen zu bilden. Aufgrund der topografischen Verhältnisse (breiter Kessel) können die natürlicherweise auftretenden Hochwasserereignisse nicht mehr genug Kraft entwickeln, um grossflächige Vegetationsbestände zu entwurzeln. Damit verbunden ist eine rasche Ausbreitung an Grünerlenbeständen, die mittelfristig die heutige Triftaue fast vollständig besiedeln werden. Im Rahmen des Triftprojekts (Vergrösserung des Triftsees mit neuem Kraftwerk auf Höhe der bestehenden Triftfassung) wurden u.a. detaillierte Studien zum Ist-Zustand sowie zur Entwicklung der Triftaue mit und ohne Projekt durchgeführt. Basierend auf diesen Untersuchungen wurden für die Realisierung des Projekts neben dem Restwasserregime zusätzlich auch Hochwasserdotierungen festgelegt

Conserved Genes Act as Modifiers of Invertebrate SMN Loss of Function Defects

Spinal Muscular Atrophy (SMA) is caused by diminished function of the Survival of Motor Neuron (SMN) protein, but the molecular pathways critical for SMA pathology remain elusive. We have used genetic approaches in invertebrate models to identify conserved SMN loss of function modifier genes. Drosophila melanogaster and Caenorhabditis elegans each have a single gene encoding a protein orthologous to human SMN; diminished function of these invertebrate genes causes lethality and neuromuscular defects. To find genes that modulate SMN function defects across species, two approaches were used. First, a genome-wide RNAi screen for C. elegans SMN modifier genes was undertaken, yielding four genes. Second, we tested the conservation of modifier gene function across species; genes identified in one invertebrate model were tested for function in the other invertebrate model. Drosophila orthologs of two genes, which were identified originally in C. elegans, modified Drosophila SMN loss of function defects. C. elegans orthologs of twelve genes, which were originally identified in a previous Drosophila screen, modified C. elegans SMN loss of function defects. Bioinformatic analysis of the conserved, cross-species, modifier genes suggests that conserved cellular pathways, specifically endocytosis and mRNA regulation, act as critical genetic modifiers of SMN loss of function defects across species

A Review of Ecological Restoration Research in the Global South and North to Promote Knowledge Dialogue

To determine global trends in ecological restoration (ER) research, we conducted a geographically-explicit English-language literature review. We assessed a representative sample (n=603) of publications that use the ER concept (n=8,678). Only 19.2% (n=118) were explicit ER studies, and these were evaluated to determine geographic location, research framework, ER paradigm, journal disciplinary orientation, article type, disturbance factor studied, and ER-response measurements. The Global North produced 2x more studies than the South, and ecological research frameworks predominated overall. However, significantly more Southern studies operated under a postmodern paradigm (i.e., addressing ecosystem processes, functions and health) than in the North, where more studies sought to reconstitute pre-disturbance biotic assemblages (i.e., classical paradigm). Both regions published mostly in natural science journals, but significantly more in the North; in the South, there were significantly more publications in engineering journals. An incipient socio-ecological research framework was detected in the North (23.1%) and South (32.5%), but social science studies were only found in the North (11.5%). Plus, the North had significantly more conceptual publications. Opportunities exist in both regions to enhance a holistic ER perspective. Southern scientists and practitioners could pay attention to context-specific concepts and approaches. Understanding global and regional ER research trends can contribute to improving theoretical, practical and ethical outcomes.Fil: Ballari, Sebastián A.. Ministerio de Ambiente y Desarrollo Sustentable. Administración de Parques Nacionales. Parque Nacional "Nahuel Huapi". Departamento Conservación y Educación Ambiental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; ArgentinaFil: Roulier, Catherine Solange. Universidad Nacional de Tierra del Fuego. Instituto de Cultura, Sociedad y Estado; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Nielsen, Erik. Northern Arizona University; Estados UnidosFil: Pizarro, J. Cristobal. Universidad de Concepción; Chile. Centro para el Impacto Socioeconómico de las Políticas Ambientales; ChileFil: Anderson, Christopher Brian. Universidad Nacional de Tierra del Fuego; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentin

SiPM-based neutron Anger camera with auto-calibration capabilities

International audienceWe present characterization results of a neutron Anger camera based on a lithium-6 loaded cerium activated silicate glass scintillator (33.3 × 33.3 × 1 mm3) and an array of 64 silicon photomultipliers. Reconstruction of the scintillation events is performed with a statistical method, implemented on a graphics processing unit (GPU). We demonstrate that the light response model of the detector can be obtained from flood irradiation calibration data using an unsupervised iterative procedure. The useful field of view is 28 × 28 mm2. The spatial resolution measured at 2.5 Å neutron beam is better than 0.6 mm FWHM and the energy resolution at the neutron peak is 11%

Preserving computational topology by subdivision of quadratic & cubic Bézier curves

Non-self-intersection is both a topological and a geometric property. It is known that non-self-intersecting regular Bézier curves have non-self-intersecting control polygons, after sufficiently many uniform subdivisions. Here a sufficient condition is given within R 3 for a non-self-intersecting, regular C 2 cubic Bézier curve to be ambient isotopic to its control polygon formed after sufficiently many subdivisions. The benefit of using the control polygon as an approximant for scientific visualization is presented in this paper