528 research outputs found
Caracterización geofísica de los "greens" de un campo de golf regado con agua regenerada. Aproximación textural e hidrológica
No full textMàster oficial: Aigua. Anàlisi Interdisciplinària i Gestió Sostenible. Institut de Recerca de l'Aigua, curs: 2010, Tutors: Josefina C. Tapias i Mahjoub HimiEste estudio tiene la finalidad de caracterizar los "greens" de un campo de golf desde un punto de vista edáfico, así como geofísico. Si bien han habido diferentes trabajos que han estudiado los campos de golf a partir de datos edáficos, la utilización de un método geofísico como la tomografía eléctrica para caracterizar los campos de golf no ha sido muy común. La correlación de los análisis químicos, físicos y físico-químicos con la información extraída de la geofísica constituye el carácter innovador del presente trabajo; asimismo al utilizar diferentes técnicas se aborda el problema con la pluridisciplinaridad que da nombre al propio Máster
The vertex k-cut problem
No full textGiven an undirected graph G=(V,E), a vertex k-cut of G is a vertex subset of V the removing of which disconnects the graph in at least k components. Given a graph G and an integer k≥2, the vertex k-cut problem consists in finding a vertex k-cut of G of minimum cardinality. We first prove that the problem is NP-hard for any fixed k≥3. We then present a compact formulation, and an extended formulation from which we derive a column generation and a branching scheme. Extensive computational results prove the effectiveness of the proposed methods
Romanzo e storia. Prospettive contemporanee
No full textFascicolo monografico dedicato al rapporto tra romanzo contemporaneo e storia. Contiene interventi su Robert Merle, Jamal Mahjoub, Amitav Ghosh, Arturo Pérez-Reverte, Christoph Hein, Kim Scott, e Antonio Scurati
Gap inequalities for the max-cut problem: a cutting-plane algorithm
No full textLaurent & Poljak introduced a class of valid inequalities for the max-cut problem, called gap inequalities, which include many other known inequalities as special cases. The gap inequalities have received little attention and are poorly understood. This paper presents the first ever computational results. In particular, we describe a cutting-plane scheme based on an effective heuristic separation algorithm for gap inequalities, and show that these yield extremely strong upper bounds in practice
Ki-covers I: Complexity and polytopes
No full textAbstractA Ki in a graph is a complete subgraph of size i. A Ki-cover of a graph G(V, E is a set C of Ki − 1's of G such that every Ki in G contains at least one Ki − 1 in C. Thus a K2-cover is a vertex cover. The problem of determining whether a graph has a Ki-cover (i ⩾ 2) of cardinality ⩽k is shown to be NP-complete for graphs in general. For chordal graphs with fixed maximum clique size, the problem is polynomial; however, it is NP-complete for arbitrary chordal graphs when i ⩾ 3. The NP-completeness results motivate the examination of some facets of the corresponding polytope. In particular we show that various induced subgraphs of G define facets of the Ki-cover polytope. Further results of this type are also produced for the K3-cover polytope. We conclude by describing polynomial algorithms for solving the separation problem for some classes of facets of the Ki-cover polytope
Molecular characterization of echinococcus granulosus in tunisia and mauritania by mitochondrial rrnS gene sequencing
No full textCystic hydatid disease is a zoonotic parasitic disease caused by the cestode Echinococcus granulosus and represents a major public health problem in many countries around the world, including North Africa. E. granulosus exists as a series of genetic variants or strains which differ in a wide variety of criteria that impact on the epidemiology, pathology and control of cystic hydatid disease. Nucleotide sequencing of the mitochondrial rrnS gene was here used to characterize 38 E. granulosus isolates collected from different regions and hosts in Tunisia and Mauritania. The results obtained reveal a significant genetic differentiation between E. granulosus hydatid cysts identified as belonging to the G1 genotype and to the G6/G7 cluster using the rrnS gene as marker, and indicate the circulation of the common sheep strain (G1) in all host species from Tunisia and the camel/pig strain cluster (G6/G7) in camel from Mauritania. Other investigations, using this method, are necessary for further genetic analysis of a wider range of isolates from different host species in order to more fully understand the genetic structure of E. granulosus populations and their transmission dynamics in this and neighbouring African countries
Canada: Muhammad Zeki Muhammad Mahjoub
No full textA document from Amnesty International's Urgent Action Networ
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