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The ESEOO Project, launched after the Prestige crisis, has boosted operational oceanography capacities in Spain, creating new operational oceanographic services and increasing synergies between these new operational tools and already existing systems. In consequence, the present preparedness to face an oil-spill crisis is enhanced, significantly improving(More)
We present two algorithms to perform computations over Markov chains. The first one determines whether the sequence of powers of the transition matrix of a Markov chain converges or not to a limit matrix. If it does converge, the second algorithm enables us to estimate this limit. The combination of these algorithms allows the computation of a limit using(More)
In the context of the degree/diameter problem, the ‘defect’ of a graph represents the difference between the corresponding Moore bound and its order. Thus, a graph with maximum degree d and diameter two has defect two if its order is n = d − 1. Only four extremal graphs of this type, referred to as (d, 2, 2)-graphs, are known at present: two of degree d = 3(More)
We give a formal definition of a new product of bipartite digraphs, the Manhattan product, and we study some of its main properties. It is shown that if all the factors of the above product are (directed) cycles, then the digraph obtained is a Manhattan street network. To this respect, it is proved that many properties of these networks, such as high(More)
Almost Moore digraphs appear in the context of the degree/diameter problem as a class of extremal directed graphs, in the sense that their order is one less than the unattainable Moore bound M(d, k) = 1 + d + · · · + dk, where d > 1 and k > 1 denote the maximum out-degree and diameter, respectively. So far, the problem of their existence has only been(More)
The abundant computing resources in current organizations provide new opportunities for executing parallel scientific applications and using resources. The Enterprise Desktop Grid Computing (EDGC) paradigmaddresses the potential for harvesting the idle computing resources of an organization’s desktop PCs to support the execution of the company’s large-scale(More)
An almost Moore (d, k)-digraph is a regular digraph of degree d > 1, diameter k > 1 and order N (d, k) = d + d2 + · · · + dk . So far, their existence has only been showed for k = 2. Their nonexistence has been proved for k = 3, 4 and for d = 2, 3 when k ≥ 3. In this paper, we prove that (4, k) and (5, k)-digraphs with self-repeats do not exist for(More)
This paper attempts to measure the levels of infertility and low fertility and sterility in Africa. In defining the measures, the words "fecundity" and "infecundity" are used to refer to the quantitative study of phenomena directly related to the presence or absence of procreation of children in a population or subpopulation. Similarly, fertility and(More)