108 research outputs found

    Safe solutions for walks on graphs

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    In this thesis we study the concept of “safe solutions” in different problems whose solutions are walks on graphs. A safe solution to a problem X can be understood as a partial solution common to all solutions to problem X. In problems whose solutions are walks on graphs, safe solutions refer to walks common to all walks which are solutions to the problem. In this thesis, we focused on formulating four main graph traversal problems and finding characterizations for those walks contained in all their solutions. We give formulations for these graph traversal problems, we prove some of their combinatorial and structural properties, and we give safe and complete algorithms for finding their safe solutions based on their characterizations. We use the genome assembly problem and its applications as our main motivating example for finding safe solutions in these graph traversal problems. We begin by motivating and exemplifying the notion of safe solutions through a problem on s-t paths in undirected graphs with at least two non-trivial biconnected components S and T and with s ∈ S, t ∈ T . We continue by reviewing similar and related notions in other fields, especially in combinatorial optimization and previous work on the bioinformatics problem of genome assembly. We then proceed to characterize the safe solutions to the Eulerian cycle problem, where one must find a circular walk in a graph G which traverses each edge exactly once. We suggest a characterization for them by improving on (Nagarajan, Pop, JCB 2009) and a polynomial-time algorithm for finding them. We then study edge-covering circular walks in a graph G. We look at the characterization from (Tomescu, Medvedev, JCB 2017) for their safe solutions and their suggested polynomial-time algorithm and we show an optimal O(mn)-time algorithm that we proposed in (Cairo et al. CPM 2017). Finally, we generalize this to edge-covering collections of circular walks. We characterize safe solutions in an edge-covering setting and provide a polynomial-time algorithm for computing them. We suggested these originally in (Obscura et al. ALMOB 2018)

    O SUBSÍDIO DO DESEMPREGO COMO MEDIDA ESTATAL DE PROTEÇÃO DO TRABALHADOR

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    The article examines the effectiveness of the “unemployment compensation”, based on the decision rendered by the Supreme Court of Justice in the Patterer, Susana Alicia v. Estado Nacional on Amparo[1]  “Patterer, Susana Alicia c/ Estado Nacional s/ Amparo” case. In said ruling, the Emergency (Executive) Order Nº267/2006 [Decreto de Necesidad y Urgencia Nº267/2006] that establishes the amount of earnings to be received by unemployed workers, known as “unemployment assistance or compensation” was declared unconstitutional by the Highest Court. In said decision, the Supreme Court of Justice of Argentina examines the government lack of protection towards unemployed workers, and shows that the benefit granted by Act 24.013 [Ley 24.013] (National Labour Law) is ineffective compared to the provisions that gave rise to it, such as section 14 bis of the National Constitution of Argentina and Human Rights treaties with constitutional hierarchy (section 75, subsection 22 of the National Constitution of Argentina).Moreover, government fails to implement measures that give some sort of answer to the “unemployed”.Este artículo analiza la efectividad de la "Prestación por Desempleo" a partir de la declaración por parte de la Corte Suprema de Justicia de la Nación en la sentencia dictada en el caso "Patterer, Susana Alicia c/Estado Nacional s/Amparo", en dicho pronunciamiento, el Tribunal Superior de Justicia declaró la inconstitucionalidad del Decreto de Necesidad y Urgencia Nº 267/2006, el mismo establece los montos a percibir por los trabajadores desempleados, en el carácter de "Subsidio o Prestación de Desempleo". En este fallo, la Corte Suprema de Justicia de la Nación analiza la falta de protección por parte del Estado a los trabajadores desempleados, demuestra que el beneficio otorgado por la Ley 24.013 (Ley Nacional del Trabajo), resulta ineficaz frente a las disposiciones que dieron origen a su conformación, como es el artículo 14 bis de la Constitución Nacional y los Tratados de Derechos Humanos de raigambre constitucional (art. 75 inciso 22 de la Constitución Nacional). Este artigo analisa a eficácia do “Subsídio Desemprego” com base na declaração do Supremo Tribunal de Justiça da Nação na sentença proferida no caso “Patterer, Susana Alicia v/Estado Nacional s/Amparo”, não referido na decisão. O Superior Tribunal de Justiça declarou a inconstitucionalidade do Decreto de Necessidade e Urgência nº 267/2006, que estabelece os valores a serem recebidos pelos trabalhadores desempregados, sob o título de “Auxílio-Unemprego”. Esta decisão, em que o Supremo Tribunal de Justiça da Nação analisa a falta de proteção do Estado aos trabalhadores desempregados, mostra que o benefício concedido pela Lei 24.013 (Lei Nacional do Trabalho) é ineficaz em comparação com as disposições que desmembram a sua origem, como artigo 14 bis da Constituição Nacional e dos Tratados de Direitos Humanos de origem constitucional (art. 75 parágrafo 22 da Constituição Nacional).  Este artigo analisa a eficácia do “Subsídio Desemprego” com base na declaração do Supremo Tribunal de Justiça da Nação na sentença proferida no caso “Patterer, Susana Alicia v/Estado Nacional s/Amparo”, não referido na decisão. O Superior Tribunal de Justiça declarou a inconstitucionalidade do Decreto de Necessidade e Urgência nº 267/2006, que estabelece os valores a serem recebidos pelos trabalhadores desempregados, sob o título de “Auxílio-Unemprego”. Esta decisão, em que o Supremo Tribunal de Justiça da Nação analisa a falta de proteção do Estado aos trabalhadores desempregados, mostra que o benefício concedido pela Lei 24.013 (Lei Nacional do Trabalho) é ineficaz em comparação com as disposições que desmembram a sua origem, como artigo 14 bis da Constituição Nacional e dos Tratados de Direitos Humanos de origem constitucional (art. 75 parágrafo 22 da Constituição Nacional).

    Cepas de Trypanosoma cruzi en el Paraguay

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    Las poblaciones del Trypanosoma cruzi que circulan en Paraguay han mostrado una gran diversidad genética, la cual ha sido evaluada usando diferentes metodologías y técnicas. Se han identificado varios genotipos de este parásito infectando una diversidad de hospederos, incluyendo pacientes, vinchucas, animales silvestres y domésticos de diferentes regiones. La diversidad genética observada en los aislados de nuestro país podría implicar diferencias en las manifestaciones clínicas de la enfermedad de Chagas, así como diferencias en sus características biológicas, como ser el grado de infectividad, virulencia, patogenicidad, capacidad antigénica y susceptibilidad o resistencia a las drogas tripanocidas. Hasta el momento, estos aspectos han sido poco explorados y evaluados en las cepas paraguayas. El aislamiento e identificación del grupo y subgrupos de T. cruzi, que circulan en los diferentes ciclos de transmisión en una determinada región geográfica, siguen siendo relevantes porque permiten conocer la dinámica de transmisión del parásito y evaluar el riesgo de introducción a partir de focos selváticos

    Optimal Omnitig Listing for Safe and Complete Contig Assembly

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    Genome assembly is the problem of reconstructing a genome sequence from a set of reads from a sequencing experiment. Typical formulations of the assembly problem admit in practice many genomic reconstructions, and actual genome assemblers usually output contigs, namely substrings that are promised to occur in the genome. To bridge the theory and practice, Tomescu and Medvedev [RECOMB 2016] reformulated contig assembly as finding all substrings common to all genomic reconstructions. They also gave a characterization of those walks (omnitigs) that are common to all closed edge-covering walks of a (directed) graph, a typical notion of genomic reconstruction. An algorithm for listing all maximal omnitigs was also proposed, by launching an exhaustive visit from every edge. In this paper, we prove new insights about the structure of omnitigs and solve several open questions about them. We combine these to achieve an O(nm)-time algorithm for outputting all the maximal omnitigs of a graph (with n nodes and m edges). This is also optimal, as we show families of graphs whose total omnitig length is Omega(nm). We implement this algorithm and show that it is 9-12 times faster in practice than the one of Tomescu and Medvedev [RECOMB 2016]

    ESTRUCTURA TRÓFICA DE LA COMUNIDAD DE INSECTOS ACUÁTICOS Y CALIDAD BIOLÓGICA DEL AGUA EN UN TRAMO DE LOS RÍOS LIMÓN, LOVAINA, ROSARIO 1, ROSARIO 2, PIXVAE Y DE MONA, EN EL CORREGIMIENTO DE PIXVAE, DISTRITO DE LAS PALMAS, PROVINCIA DE VERAGUAS.

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    Sampling stations were established in a 50 m. section of the Limón, Lovaina, Rosario1, Rosario2, Pixvae, and De Mona revers, to determine the biological water quality and the trophic structure of the associated aquatic insect communities.  Sampling was conducted from December 2019 until May 2021, for a total of 10 sampling campaigns for all rivers. Each genus found was assigned to a functional feeding group reported for the Neotropics. Specimens lacking feeding group information for the Neotropics were assigned a proposed group from the temperate zone. The BMWP-Veraguas were used for the biological water quality analysis. The studied sections of Limón, Lovaina, and Rosario1 showed category I water quality, which is considered clean, non-polluted water, while segments from Rosario2 and De Mona rivers showed category II water quality, which indicates water without sensitive alteration. The Pixvae river showed category III water quality, which means it had evident pollution effects. The cluster analysis performed with absence-presence of genera, through the Jaccard similarity coefficient and complete linkage allowed observation of 3 groups. Group 1 consisted of Limón, Lovaina, and Rosario1, while group 2 was formed by the Pixvae river, and group 3 included rivers Rosario 2 and De Mona. Community similarity in genus structure seems to indicate that studied river sections have the same biological water quality and the same trophic structure as well.  Con la finalidad de determinar la calidad biológica del agua y la estructura trófica de la comunidad de insectos acuáticos asociados a un tramo de los ríos Limón, Lovaina, Rosario1, Rosario2, Pixvae y De Mona, se establecieron en cada tramo, una estación de muestreo con una longitud de 50 m. Los muestreos se realizaron desde diciembre de 2019 hasta mayo de 2021, para un total de 10 campañas de muestreo. A cada género encontrado se le asignó el grupo funcional de alimentación reportado en la literatura para el Neotrópico, los especímenes carentes de información para la región neotropical, se les asignó el grupo funcional de alimentación propuesto para la zona templada. Para el análisis de la calidad biológica del agua se utilizo el índice BMWP-Veraguas. Los tramos estudiados de los ríos Limón, Lovaina y Rosario 1  presentaron una calidad biológica del agua categoría I, que es considerada agua limpia no contaminada, mientras que, los ríos Rosario2 y De Mona mostraron una categoria II, aguas no alteradas de modo sensible. El río Pixvae mostró una categoria de agua III, lo que significa que tiene evidentes efectos de contaminación. El análisis Cluster, hecho con la ausencia y presencia de géneros, mediante el coeficiente de similitud de Jaccard y vinculacion completa, se pudo observar claramente  la formación de tres grupos. El grupo 1, formado por los ríos Limón, Lovaina y Rosario1, el grupo 2, formado por el río Pixvae y el grupo 3, formado por los ríos Rosario 2 y De Mona. Lo que parece indicar que los tramos de los ríos estudiados, con similitud en sus comunidades en cuanto a la estructura de géneros, tuvieron la misma calidad biológica del agua y la misma estructura trófica

    Las relaciones de China y la India con América Latina y el Caribe

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    This paper addresses the characteristics of the relations between Latin American and Caribbean coun- tries, India and China. It takes into account the vision of cooperation, especially between China and Latin America and the Caribbean, as well as its characteristics. It deals with the impact of these relations from the adhesion of the countries of the area in the mega project of the Belt and Road and in the context of the pandemic. It also characterizes the presence of India. Beyond geographical remoteness, what is at stake to- day is to look not only to the "North" but also to the "South" as an alternative to the identification of similar development needs, albeit with different strategies.El trabajo aborda las características de las relaciones entre los países de América Latina y el Caribe, India y China. Tiene en cuenta la visión de la cooperación, sobre todo, entre China y Latinoamérica y el Caribe, así como las características de la misma. Se aborda el impacto de dichas relaciones a partir de la adhe- sión de los países del área en el mega proyecto de la Franja y la Ruta y en el contexto de la pandemia. Asimismo, caracteriza la presencia de la India. Mas allá de la lejanía geográfica, de lo que se trata hoy es de mirar no solo al “Norte” sino también al “Sur” como alternativa a la identificación de necesidades de desarrollo parecidas, aunque con estrategias diferentes

    Improved Pattern-Avoidance Bounds for Greedy BSTs via Matrix Decomposition

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    Greedy BST (or simply Greedy) is an online self-adjusting binary search tree defined in the geometric view ([Lucas, 1988; Munro, 2000; Demaine, Harmon, Iacono, Kane, Patrascu, SODA 2009). Along with Splay trees (Sleator, Tarjan 1985), Greedy is considered the most promising candidate for being dynamically optimal, i.e., starting with any initial tree, their access costs on any sequence is conjectured to be within O(1)O(1) factor of the offline optimal. However, in the past four decades, the question has remained elusive even for highly restricted input. In this paper, we prove new bounds on the cost of Greedy in the ''pattern avoidance'' regime. Our new results include: The (preorder) traversal conjecture for Greedy holds up to a factor of O(2α(n))O(2^{\alpha(n)}), improving upon the bound of 2α(n)O(1)2^{\alpha(n)^{O(1)}} in (Chalermsook et al., FOCS 2015). This is the best known bound obtained by any online BSTs. We settle the postorder traversal conjecture for Greedy. The deque conjecture for Greedy holds up to a factor of O(α(n))O(\alpha(n)), improving upon the bound 2O(α(n))2^{O(\alpha(n))} in (Chalermsook, et al., WADS 2015). The split conjecture holds for Greedy up to a factor of O(2α(n))O(2^{\alpha(n)}). Key to all these results is to partition (based on the input structures) the execution log of Greedy into several simpler-to-analyze subsets for which classical forbidden submatrix bounds can be leveraged. Finally, we show the applicability of this technique to handle a class of increasingly complex pattern-avoiding input sequences, called kk-increasing sequences. As a bonus, we discover a new class of permutation matrices whose extremal bounds are polynomially bounded. This gives a partial progress on an open question by Jacob Fox (2013).Comment: Accepted to SODA 202

    Trypanosoma cruzi IIc: phylogenetic and phylogeographic insights from sequence and microsatellite analysis and potential impact on emergent Chagas disease.

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    Trypanosoma cruzi, the etiological agent of Chagas disease, is highly genetically diverse. Numerous lines of evidence point to the existence of six stable genetic lineages or DTUs: TcI, TcIIa, TcIIb, TcIIc, TcIId, and TcIIe. Molecular dating suggests that T. cruzi is likely to have been an endemic infection of neotropical mammalian fauna for many millions of years. Here we have applied a panel of 49 polymorphic microsatellite markers developed from the online T. cruzi genome to document genetic diversity among 53 isolates belonging to TcIIc, a lineage so far recorded almost exclusively in silvatic transmission cycles but increasingly a potential source of human infection. These data are complemented by parallel analysis of sequence variation in a fragment of the glucose-6-phosphate isomerase gene. New isolates confirm that TcIIc is associated with terrestrial transmission cycles and armadillo reservoir hosts, and demonstrate that TcIIc is far more widespread than previously thought, with a distribution at least from Western Venezuela to the Argentine Chaco. We show that TcIIc is truly a discrete T. cruzi lineage, that it could have an ancient origin and that diversity occurs within the terrestrial niche independently of the host species. We also show that spatial structure among TcIIc isolates from its principal host, the armadillo Dasypus novemcinctus, is greater than that among TcI from Didelphis spp. opossums and link this observation to differences in ecology of their respective niches. Homozygosity in TcIIc populations and some linkage indices indicate the possibility of recombination but cannot yet be effectively discriminated from a high genome-wide frequency of gene conversion. Finally, we suggest that the derived TcIIc population genetic data have a vital role in determining the origin of the epidemiologically important hybrid lineages TcIId and TcIIe

    Exponer la importancia del proceso de egreso hospitalario en el servicio de urgencias de la Sociedad de Cirugía del Hospital San José de Bogotá

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    El presente documento tiene como fin diseñar un proceso de egreso hospitalario, en la Sociedad de Cirugía del Hospital San José de Bogotá, dentro del servicio de urgencias, que genere una mejora en la productividad de la organización, dentro del marco normativo colombiano buscando mejorar el nivel de calidad y mantener la acreditación en salud otorgada por el ICONTEC. Para esto, se abordó el egreso Hospitalario en 3 módulos administrativos los cuales son: Gerencia estratégica y de servicios, auditoría y control de calidad en salud y desarrollo organizacional. El módulo de desarrollo organizacional, se orientó con el fin de conocer que impacto tienen en el factor económico el egreso hospitalario. Puesto que la contabilidad juega un papel importante al interior de la organización, esta debe satisfacer las necesidades de los usuarios tanto internos como externos con la contabilidad administrativa y la contabilidad financiera respectivamente. El módulo de gerencia estratégica y de servicios, fue de vital importancia porque demostró como el egreso hospitalario influye en el deterioro del desarrollo de la planeación estratégica, abordando así la problemática desde la gerencia, lo cual permitió generar estrategias basándonos en modelos DOFA y la matriz de las cinco fuerzas de Porter. El módulo de auditoría y control de la calidad se abordó porque se pudo evidenciar según las gráficas 1 al 5, que no existe el diligenciamiento de formulario de recomendaciones y cuidados en el área de urgencias, pues la atención más detallada generalmente se vincula con procesos quirúrgicos o de hospitalización en los servicios de especialidades. Demostrando que es posible la mejora en el control de calidad en la prestación del servicio por parte del personal. Al tener claro la parte de gestión económica, el proceso de toma de decisiones entra a tomar el protagonismo, de la mano de estados financieros claros, transparentes, comparables, pertinentes y confiables. Aquí, la responsabilidad del Gerente en Salud en las finanzas es fundamental en la gestión empresarial, pues de esta manera se evidencia el cumplimiento de los objetivos a nivel organizacional y la optimización de los recursos económicos. Esto permite medir la eficiencia y eficacia en los procesos del Hospital San José.EspecializaciónEspecialista En Gerencia De La Salu

    Cuidados intensivos. Bloque IV. Atención de enfermería a pacientes con problemas renales

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    Se explica el IV Bloque modular para planes y programas de cuidados intensivos a nivel renal dirigido a auxiliares de enfermería justificado por el número de pacientes con insuficiencia renal crónica que llegan a unidades de cuidados intensivos y la necesidad de contar con personal capacitado para atenderlosIt explains the IV Modular block for plans and programs of intensive care at the renal level directed to nursing assistants justified by the number of patients with chronic renal failure who reach intensive care units and the need to have staff trained to attend themna41 página
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