54 research outputs found

    Rank-width and Tree-width of H-minor-free Graphs

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    We prove that for any fixed r>=2, the tree-width of graphs not containing K_r as a topological minor (resp. as a subgraph) is bounded by a linear (resp. polynomial) function of their rank-width. We also present refinements of our bounds for other graph classes such as K_r-minor free graphs and graphs of bounded genus.Comment: 17 page

    Использование транспортной телематики и дистанционной диагностики для совершенствования технического обслуживания и ремонта транспортных средств

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    The article considers the possibility of using planned-prevention system in modern conditions. The system of vehicle telematics and remote diagnostics allows you to automate the getting of correction coefficients to determine the standard values of labor intensity of maintenance and repair and make calculations with high accuracy. The mileage before major repairs or write-off of the vehicle set by the manufacturer is also corrected for coefficients. The use tools of navigation allows you to determine the location of the vehicle in the coordinates of navigation maps with characteristics of the road surface, locality, with the definition of height above sea level and road-climate zoning. This method is an alternative solution that allows you to automate the mileage and labor intensity of technical actions and can be used to clarification parameters. To implement these principles, we propose a flowchart for processing transport telematics data for calculating correction coefficients, followed by calculating the periodicity and labor intensity. The proposed flowchart is implemented by a standard vehicle telematics system, but it can be upgraded with the possibility of remote diagnostics, which allows performing the functions of general diagnostics of individual systems and the vehicle as a whole. The use of systems of transport monitoring make it possible to improve the system of maintenance and repair. Analysis of the existing requirements regulated by documents in the perspective of the capabilities of modern transport telematics systems allows us to justify and create a new approach to the calculation of mileage before technical impacts and adjust the standards for the complexity of performing these impacts. The introduction of the general remote diagnostics function for individual systems and the vehicle as a whole makes it possible to eliminate errors in the calculation of correction coefficients, as well as to prevent the occurrence of failures during operation.Рассматривается возможность применения планово-предупредительной системы в современных условиях. Система телематики транспортных средств и дистанционной диагностики позволяют автоматизировать получение корректирующих коэффициентов для определения нормативных значений трудоемкости технического обслуживания и ремонта и производить расчеты, как предполагается, с приемлемой для прикладного применения точностью. Пробег до капитального ремонта или списания транспортного средства, установленный заводом-изготовителем, также корректируется с учетом коэффициентов. Использование средств навигации позволяет определять расположение транспортного средства в координатах карт навигации с характеристиками дорожного покрытия, населенного пункта, с определением высоты над уровнем моря и дорожно-климатического районирования. Данный способ является альтернативным решением, позволяющим автоматизировать пробеги и трудоемкость технических воздействий и может быть применен для уточнения параметров. Для реализации заложенных принципов предлагается блок-схема обработки данных транспортной телематики с целью определения корректирующих коэффициентов с последующим расчетом периодичностей и трудоемкостей. Предложенная блок-схема реализуется стандартной системой телематики транспортного средства, однако возможна модернизация с возможностью дистанционной диагностики, позволяющей выполнять функции общей диагностики отдельных систем и транспортного средства в целом. Использование систем мониторинга транспорта позволяет усовершенствовать систему технического обслуживания и ремонта. Анализ существующих требований, регламентируемых документами в ракурсе возможностей современных систем транспортной телематики, позволяет обосновать и развивать новый подход к расчету пробегов до технических воздействий и скорректировать нормативы трудоемкостей выполнения этих воздействий. Внедрение функции общей дистанционной диагностики отдельных систем и транспортного средства в целом делает возможным исключение погрешности при расчетах корректирующих коэффициентов, а также упреждение возникновения отказов в процессе эксплуатации

    Locally constrained homomorphisms on graphs of bounded treewidth and bounded degree.

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    A homomorphism from a graph G to a graph H is locally bijective, surjective, or injective if its restriction to the neighborhood of every vertex of G is bijective, surjective, or injective, respectively. We prove that the problems of testing whether a given graph G allows a homomorphism to a given graph H that is locally bijective, surjective, or injective, respectively, are NP-complete, even when G has pathwidth at most 5, 4 or 2, respectively, or when both G and H have maximum degree 3. We complement these hardness results by showing that the three problems are polynomial-time solvable if G has bounded treewidth and in addition G or H has bounded maximum degree

    Compact Labelings For Efficient First-Order Model-Checking

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    We consider graph properties that can be checked from labels, i.e., bit sequences, of logarithmic length attached to vertices. We prove that there exists such a labeling for checking a first-order formula with free set variables in the graphs of every class that is \emph{nicely locally cwd-decomposable}. This notion generalizes that of a \emph{nicely locally tree-decomposable} class. The graphs of such classes can be covered by graphs of bounded \emph{clique-width} with limited overlaps. We also consider such labelings for \emph{bounded} first-order formulas on graph classes of \emph{bounded expansion}. Some of these results are extended to counting queries

    Indução de aderência intrabdominal por prótese de retícula de polipropileno:: estudo experimental em ratos

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    INTRODUCTION: The correction of groin hernias using a transperitoneal videolaparoscopic method with a polypropylene mesh is becoming increasingly common. This could lead to an increased incidence of adhesion formation.MATERIALS AND METHODS: The incidence of adhesions induced by mesh placement and by reperitonization was observed in 40 male adult Wistar rats, randomlyallocated to four groups of 10 rats (Group A = no mesh, no reperitonization; B = no mesh, reperitonization; C = mesh, no reperitonization; D = mesh and reperitonization). After opening the abdominal cavity, the iliac fossa was identified and a peritoneal opening, measuring about 2 by 2 cm, was done on the parietal wall. In the rats in which a polypropylene prosthesis was used, a piece of Marlex mesh, measuring about 1.5 by 1.5 cm was placed on the peritoneal opening. A simple suture was performed in the animals submitted to reperitonization, using a 5.0 monofilamentar polypropylene thread on a cardiovascular (atraumatic) needle. The animals were killed 15 days after the operation. Macroscopic analysis was done by an investigator blinded to intervention group. Fisher’s exact test and the c2 test were used for statistical analysis of the results. A P < 0.05 was considered as significant.RESULTS: Adhesions were significantly more common in the groups in which the prosthesis was placed (59% vs. 95%; P = 0.01), as well as in the groups in whichreperitonization was performed (58% vs. 100%; P = 0.03).CONCLUSIONS: The results suggest that polypropylene mesh placement and reperitonization are each independent factors that have a role in inducing the formationof adhesions.INTRODUÇÃO: A correção de hérnias na virilha através de um método videolaparoscópico transperitoneal está se tornando cada vez mais comum. Contudo,este método poderia levar a um aumento na incidência de formação de aderências.MATERIAIS E MÉTODOS: A incidência de aderências induzidas pela colocação de retícula e pela reperitonização foram observadas em 40 ratos Wistar adultos, machos, divididos aleatoriamente em quatro grupos com 10 ratos cada um (Grupo A = sem retícula, sem reperitonização; B = sem retícula, com reperitonização; C = com retícula, sem reperitonização; D = retícula e reperitonização). Após a abertura da cavidade abdominal, a fossa ilíaca foi identificada e fez-se uma abertura de aproximadamente 2 x 2 cm na parede parietal. Nos ratos em que uma prótese de polipropileno foi utilizada, uma retícula Marlex com 1,5 x 1,5 cm foi colocada sobre a abertura peritoneal. Nos outros animais, a reperitonização foi feita com sutura simples, utilizando-se fio de polipropileno monofilamentar 5.0 com uma agulha cardiovascular (atraumática). Os animais foram sacrificados 15 dias depois da operação. A análise macroscópica foi realizada por um investigador cego quanto ao grupo de origem dos animais. A análise estatística utilizou o teste exato de Fisher e o c2. Um P < 0,05 foi considerado significativo.RESULTADOS: As aderências foram significativamente mais comuns nos grupos nos quais a prótese foi utilizada (59% vs. 95%; P = 0,01), assim como nos gruposnos quais foi feita a reperitonização (58% vs. 100%; P = 0,03).  CONCLUSÕES: Os resultados sugerem que a retícula de polipropileno e a reperitonização são fatores independentes entre si quanto à indução de formaçãode aderências

    Static and dynamic structure factors with account of the ion structure for high-temperature alkali and alkaline earth plasmas

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    The electron-electron, electron-ion, ion-ion and charge-charge static structure factors are calculated for alkali (at T = 30 000 K, 60 000 K, n (e) = 0.7 x 10(21) A center dot 1.1 x 10(22) cm(-3)) and Be2+ (at T = 20 eV, n (e) = 2.5 x 10(23) cm(-3)) plasmas using the method described by Gregori et al. The dynamic structure factors for alkali plasmas are calculated at T = 30 000 K, n (e) = 1.74 x 10(20), 1.11 x 10(22) cm(-3) using the method of moments developed by Adamjan et al. In both methods the screened Hellmann-Gurskii-Krasko potential, obtained on the basis of Bogolyubov's method, has been used taking into account not only the quantum-mechanical effects but also the repulsion due to the Pauli exclusion principle. The repulsive part of the Hellmann-Gurskii-Krasko (HGK) potential reflects important features of the ion structure. Our results on the static structure factors for Be2+ plasma deviate from the data obtained by Gregori et al., while our dynamic structure factors are in a reasonable agreement with those of Adamyan et al.: at higher values of k and with increasing k the curves damp down while at lower values of k, and especially at higher electron coupling, we observe sharp peaks also reported in the mentioned work. For lower electron coupling the dynamic structure factors of Li+, Na+, K+, Rb+ and Cs+ do not differ while at higher electron coupling these curves split. As the number of shell electrons increases from Li+ to Cs+ the curves shift in the direction of low absolute value of omega and their heights diminish. We conclude that the short range forces, which we take into account by means of the HGK model potential, which deviates from the Coulomb and Deutsch ones, influence the static and dynamic structure factors significantly.The work has been realised at the Humboldt University at Berlin (Germany). One of the authors (S. P. Sadykova) would like to express sincere thanks to the Erasmus Mundus Program of the EU for the financial support and especially to Mr. M. Parske for his aid, to the Institute of Physics, Humboldt University at Berlin, for the support which made her participation at some scientific Conferences possible; I. M. T. acknowledges the financial support of the Spanish Ministerio de Educacion y Ciencia Project No. ENE2007-67406-C02-02/FTN and valuable discussions with Dr. D. Gericke.Sadykova, SP.; Ebeling, W.; Tkachenko Gorski, IM. (2011). Static and dynamic structure factors with account of the ion structure for high-temperature alkali and alkaline earth plasmas. 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    Genome-wide association and Mendelian randomisation analysis provide insights into the pathogenesis of heart failure

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    Heart failure (HF) is a leading cause of morbidity and mortality worldwide. A small proportion of HF cases are attributable to monogenic cardiomyopathies and existing genome-wide association studies (GWAS) have yielded only limited insights, leaving the observed heritability of HF largely unexplained. We report results from a GWAS meta-analysis of HF comprising 47,309 cases and 930,014 controls. Twelve independent variants at 11 genomic loci are associated with HF, all of which demonstrate one or more associations with coronary artery disease (CAD), atrial fibrillation, or reduced left ventricular function, suggesting shared genetic aetiology. Functional analysis of non-CAD-associated loci implicate genes involved in cardiac development (MYOZ1, SYNPO2L), protein homoeostasis (BAG3), and cellular senescence (CDKN1A). Mendelian randomisation analysis supports causal roles for several HF risk factors, and demonstrates CAD-independent effects for atrial fibrillation, body mass index, and hypertension. These findings extend our knowledge of the pathways underlying HF and may inform new therapeutic strategies

    Genome-wide association and Mendelian randomisation analysis provide insights into the pathogenesis of heart failure

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    Abstract: Heart failure (HF) is a leading cause of morbidity and mortality worldwide. A small proportion of HF cases are attributable to monogenic cardiomyopathies and existing genome-wide association studies (GWAS) have yielded only limited insights, leaving the observed heritability of HF largely unexplained. We report results from a GWAS meta-analysis of HF comprising 47,309 cases and 930,014 controls. Twelve independent variants at 11 genomic loci are associated with HF, all of which demonstrate one or more associations with coronary artery disease (CAD), atrial fibrillation, or reduced left ventricular function, suggesting shared genetic aetiology. Functional analysis of non-CAD-associated loci implicate genes involved in cardiac development (MYOZ1, SYNPO2L), protein homoeostasis (BAG3), and cellular senescence (CDKN1A). Mendelian randomisation analysis supports causal roles for several HF risk factors, and demonstrates CAD-independent effects for atrial fibrillation, body mass index, and hypertension. These findings extend our knowledge of the pathways underlying HF and may inform new therapeutic strategies
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