69 research outputs found

    Volunteering and Civic Service in Three African Regions: Contributions to Regional Integration, Youth Development and Peace

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    This paper broadly looks at the role of youth volunteering in cultivating peace and development in Sub-Saharan Africa

    Genome aliquoting with double cut and join

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    <p>Abstract</p> <p>Background</p> <p>The <it>genome aliquoting probem </it>is, given an observed genome <it>A </it>with <it>n </it>copies of each gene, presumed to descend from an <it>n</it>-way polyploidization event from an ordinary diploid genome <it>B</it>, followed by a history of chromosomal rearrangements, to reconstruct the identity of the original genome <it>B'</it>. The idea is to construct <it>B'</it>, containing exactly one copy of each gene, so as to minimize the number of rearrangements <it>d</it>(<it>A, B' </it>⊕ <it>B' </it>⊕ ... ⊕ <it>B'</it>) necessary to convert the observed genome <it>B' </it>⊕ <it>B' </it>⊕ ... ⊕ <it>B' </it>into <it>A</it>.</p> <p>Results</p> <p>In this paper we make the first attempt to define and solve the genome aliquoting problem. We present a heuristic algorithm for the problem as well the data from our experiments demonstrating its validity.</p> <p>Conclusion</p> <p>The heuristic performs well, consistently giving a non-trivial result. The question as to the existence or non-existence of an exact solution to this problem remains open.</p

    A Unifying Model of Genome Evolution Under Parsimony

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    We present a data structure called a history graph that offers a practical basis for the analysis of genome evolution. It conceptually simplifies the study of parsimonious evolutionary histories by representing both substitutions and double cut and join (DCJ) rearrangements in the presence of duplications. The problem of constructing parsimonious history graphs thus subsumes related maximum parsimony problems in the fields of phylogenetic reconstruction and genome rearrangement. We show that tractable functions can be used to define upper and lower bounds on the minimum number of substitutions and DCJ rearrangements needed to explain any history graph. These bounds become tight for a special type of unambiguous history graph called an ancestral variation graph (AVG), which constrains in its combinatorial structure the number of operations required. We finally demonstrate that for a given history graph GG, a finite set of AVGs describe all parsimonious interpretations of GG, and this set can be explored with a few sampling moves.Comment: 52 pages, 24 figure

    On the PATHGROUPS approach to rapid small phylogeny

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    We present a data structure enabling rapid heuristic solution to the ancestral genome reconstruction problem for given phylogenies under genomic rearrangement metrics. The efficiency of the greedy algorithm is due to fast updating of the structure during run time and a simple priority scheme for choosing the next step. Since accuracy deteriorates for sets of highly divergent genomes, we investigate strategies for improving accuracy and expanding the range of data sets where accurate reconstructions can be expected. This includes a more refined priority system, and a two-step look-ahead, as well as iterative local improvements based on a the median version of the problem, incorporating simulated annealing. We apply this to a set of yeast genomes to corroborate a recent gene sequence-based phylogeny

    A simple and fast heuristic for protein structure comparison

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    Background Protein structure comparison is a key problem in bioinformatics. There exist several methods for doing protein comparison, being the solution of the Maximum Contact Map Overlap problem (MAX-CMO) one of the alternatives available. Although this problem may be solved using exact algorithms, researchers require approximate algorithms that obtain good quality solutions using less computational resources than the formers. Results We propose a variable neighborhood search metaheuristic for solving MAX-CMO. We analyze this strategy in two aspects: 1) from an optimization point of view the strategy is tested on two different datasets, obtaining an error of 3.5%(over 2702 pairs) and 1.7% (over 161 pairs) with respect to optimal values; thus leading to high accurate solutions in a simpler and less expensive way than exact algorithms; 2) in terms of protein structure classification, we conduct experiments on three datasets and show that is feasible to detect structural similarities at SCOP's family and CATH's architecture levels using normalized overlap values. Some limitations and the role of normalization are outlined for doing classification at SCOP's fold level. Conclusion We designed, implemented and tested.a new tool for solving MAX-CMO, based on a well-known metaheuristic technique. The good balance between solution's quality and computational effort makes it a valuable tool. Moreover, to the best of our knowledge, this is the first time the MAX-CMO measure is tested at SCOP's fold and CATH's architecture levels with encouraging results. Software is available for download at http://modo.ugr.es/jrgonzalez/msvns4maxcmo webcite.This work is supported by Projects HeuriCosc TIN2005-08404-C04-01, HeuriCode TIN2005-08404-C04-03, both from the Spanish Ministry of Education and Science. JRG acknowledges financial support from Project TIC2002-04242-C03-02. Authors thank N. Krasnogor and ProCKSi project (BB/C511764/1) for their support

    Desarrollo de tecnologías para evaluar la funcionalidad de pacientes con prótesis de rodilla y su uso para el seguimiento clínico post-comercialización de productos sanitarios y la estimación de indicadores de gestión hospitalaria

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    Gomez Pellin, A.; Pedrero, J.; Peris Serra, JL.; Sinovas, I.; Atienza Vicente, CM.; Garrido Jaen, JD.; Bermejo Bosch, I.... (2019). Desarrollo de tecnologías para evaluar la funcionalidad de pacientes con prótesis de rodilla y su uso para el seguimiento clínico post-comercialización de productos sanitarios y la estimación de indicadores de gestión hospitalaria. Innovación biomecánica en Europa. (8):1-4. http://hdl.handle.net/10251/167980S14

    deepBlockAlign: a tool for aligning RNA-seq profiles of read block patterns

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    Motivation: High-throughput sequencing methods allow whole transcriptomes to be sequenced fast and cost-effectively. Short RNA sequencing provides not only quantitative expression data but also an opportunity to identify novel coding and non-coding RNAs. Many long transcripts undergo post-transcriptional processing that generates short RNA sequence fragments. Mapped back to a reference genome, they form distinctive patterns that convey information on both the structure of the parent transcript and the modalities of its processing. The miR-miR* pattern from microRNA precursors is the best-known, but by no means singular, example

    Multichromosomal median and halving problems under different genomic distances

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    <p>Abstract</p> <p>Background</p> <p>Genome median and genome halving are combinatorial optimization problems that aim at reconstructing ancestral genomes as well as the evolutionary events leading from the ancestor to extant species. Exploring complexity issues is a first step towards devising efficient algorithms. The complexity of the median problem for unichromosomal genomes (permutations) has been settled for both the breakpoint distance and the reversal distance. Although the multichromosomal case has often been assumed to be a simple generalization of the unichromosomal case, it is also a relaxation so that complexity in this context does not follow from existing results, and is open for all distances.</p> <p>Results</p> <p>We settle here the complexity of several genome median and halving problems, including a surprising polynomial result for the breakpoint median and guided halving problems in genomes with circular and linear chromosomes, showing that the multichromosomal problem is actually easier than the unichromosomal problem. Still other variants of these problems are NP-complete, including the DCJ double distance problem, previously mentioned as an open question. We list the remaining open problems.</p> <p>Conclusion</p> <p>This theoretical study clears up a wide swathe of the algorithmical study of genome rearrangements with multiple multichromosomal genomes.</p
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