DSpace Community:
http://hdl.handle.net/2117/3178
Wed, 27 May 2015 18:11:12 GMT2015-05-27T18:11:12Zwebmaster.bupc@upc.eduUniversitat Politècnica de Catalunya. Servei de Biblioteques i DocumentaciónoOxidative stress is a central target for physical exercise neuroprotection against pathological brain aging
http://hdl.handle.net/2117/27948
Title: Oxidative stress is a central target for physical exercise neuroprotection against pathological brain aging
Authors: Garcia-Mesa, Yoelvis; Colie, Sandra; Corpas, Ruben; Cristofol, Rosa; Comellas Padró, Francesc de Paula; Nebreda, Angel; Giménez-Llort, Lydia; Sanfeliu, Coral
Abstract: Physical exercise is suggested for preventing or delaying senescence and Alzheimer’s disease (AD). We have examined its therapeutic value in the advanced stage of AD-like pathology in 3xTg-AD female mice through voluntary wheel running from 12 to 15 months of age. Mice submitted to exercise showed improved body fitness, immunorejuvenation, improvement of behavior and cognition, and reduced amyloid and tau pathology. Brain tissue analysis of aged 3xTg-AD mice showed high levels of oxidative damage. However, this damage was decreased by physical exercise through regulation of redox homeostasis. Network analyses showed that oxidative stress was a central event, which correlated with AD-like pathology and the AD-related behaviors of anxiety, apathy, and cognitive loss. This study corroborates the importance of redox mechanisms in the neuroprotective effect of physical exercise, and supports the theory of the crucial role of oxidative stress in the switch from normal brain aging to pathological aging and AD.Mon, 18 May 2015 12:01:12 GMThttp://hdl.handle.net/2117/279482015-05-18T12:01:12ZGarcia-Mesa, Yoelvis; Colie, Sandra; Corpas, Ruben; Cristofol, Rosa; Comellas Padró, Francesc de Paula; Nebreda, Angel; Giménez-Llort, Lydia; Sanfeliu, CoralnoAlzheimer’s disease, 3xTg-AD mice, Physical exercise, Oxidative stress, Behavior tests, Cognition, Amyloid ßPhospho-tauPhysical exercise is suggested for preventing or delaying senescence and Alzheimer’s disease (AD). We have examined its therapeutic value in the advanced stage of AD-like pathology in 3xTg-AD female mice through voluntary wheel running from 12 to 15 months of age. Mice submitted to exercise showed improved body fitness, immunorejuvenation, improvement of behavior and cognition, and reduced amyloid and tau pathology. Brain tissue analysis of aged 3xTg-AD mice showed high levels of oxidative damage. However, this damage was decreased by physical exercise through regulation of redox homeostasis. Network analyses showed that oxidative stress was a central event, which correlated with AD-like pathology and the AD-related behaviors of anxiety, apathy, and cognitive loss. This study corroborates the importance of redox mechanisms in the neuroprotective effect of physical exercise, and supports the theory of the crucial role of oxidative stress in the switch from normal brain aging to pathological aging and AD.Decomposing almost complete graphs by random trees
http://hdl.handle.net/2117/27908
Title: Decomposing almost complete graphs by random trees
Authors: Lladó Sánchez, Ana M.
Abstract: An old conjecture of Ringel states that every tree with m edges decom- poses the complete graph K 2 m +1 . A more general version of the Ringel’s conjecture says that every tree with m edges decomposes K rm +1 for each r = 2 provided that r and m + 1 are not both odd. The best lower bound for the order of a complete graph decomposed by a given tree with m edge is O ( m 3 ). We show that asymptotically almost surely a random tree with m edges and p = 2 m + 1 is a prime decomposes the complete graph minus one edge K 3 p - e . We also show that, for every prime of the form 2 km + 1 a random tree with m edges asymptotically almost surely decomposes the graph K 2 km +1 (3) obtained from the complete graph by replacing each vertex by the complement of a triangle.Wed, 13 May 2015 11:30:43 GMThttp://hdl.handle.net/2117/279082015-05-13T11:30:43ZLladó Sánchez, Ana M.noRingel Conjecture, random treesAn old conjecture of Ringel states that every tree with m edges decom- poses the complete graph K 2 m +1 . A more general version of the Ringel’s conjecture says that every tree with m edges decomposes K rm +1 for each r = 2 provided that r and m + 1 are not both odd. The best lower bound for the order of a complete graph decomposed by a given tree with m edge is O ( m 3 ). We show that asymptotically almost surely a random tree with m edges and p = 2 m + 1 is a prime decomposes the complete graph minus one edge K 3 p - e . We also show that, for every prime of the form 2 km + 1 a random tree with m edges asymptotically almost surely decomposes the graph K 2 km +1 (3) obtained from the complete graph by replacing each vertex by the complement of a triangle.A new application of the $\otimes_h$-product to $\alpha$-labelings
http://hdl.handle.net/2117/27897
Title: A new application of the $\otimes_h$-product to $\alpha$-labelings
Authors: López Masip, Susana Clara; Muntaner Batle, Francesc Antoni
Abstract: The weak tensor product was introduced by Snevily as a way to construct new graphs that admit a-labelings from a pair of known a-graphs. In this article, we show that this product and the application to a-labelings can be generalized by considering as a second factor of the product, a family G of bipartite (p, q)-graphs, p and q fixed. The only additional restriction that we should consider is that for every F ¿ G , there exists an a-labeling fF with fF (V(F )) = L¿H, where L, H ¿ [0, q] are the stable sets induced by the characteristic of fF and they do not depend on F .Wealso obtain analogous applications to near a-labelings and bigraceful labelings.Tue, 12 May 2015 11:53:58 GMThttp://hdl.handle.net/2117/278972015-05-12T11:53:58ZLópez Masip, Susana Clara; Muntaner Batle, Francesc AntoninoWeak tensor product, ¿h-product, a-labeling, Near a-labeling, Bigraceful labeling, DecompositionThe weak tensor product was introduced by Snevily as a way to construct new graphs that admit a-labelings from a pair of known a-graphs. In this article, we show that this product and the application to a-labelings can be generalized by considering as a second factor of the product, a family G of bipartite (p, q)-graphs, p and q fixed. The only additional restriction that we should consider is that for every F ¿ G , there exists an a-labeling fF with fF (V(F )) = L¿H, where L, H ¿ [0, q] are the stable sets induced by the characteristic of fF and they do not depend on F .Wealso obtain analogous applications to near a-labelings and bigraceful labelings.Caracterizaciones combinatorias y algebraicas de grafos distancia-regulares
http://hdl.handle.net/2117/27894
Title: Caracterizaciones combinatorias y algebraicas de grafos distancia-regulares
Authors: Fiol Mora, Miquel Àngel
Abstract: Los grafos distancia-regulares aparecen a menudo en el estudio de es-
tructuras matemáticas con un alto grado de simetría y/o regularidad. Un ejemplo bien conocido de tales grafos son los esqueletos de los sólidos platónicos. Desde que fueron propuestos por Norman Biggs, los grafos distancia-regulares han sido caracterizados por numerosos resultados, tanto de carácter combinatorio como algebraico. Como ejemplo del primer caso, sabemos que un grafo es distancia-regular si, y sólo si, el número de caminos de una longitud dada entre dos vértices sólo depende de la distancia entre dichos vértices. En esta charla se van a presentar y comparar las diferentes caracterizaciones conocidas, tanto las más clásicas como las que han sido recientemente descubiertas por el conferenciante y algunos de sus colaboradores. Entre las últimas, cabe destacar el que ya es conocido en la literatura com el `teorema del exceso espectral’. Este resultado puede considerarse como una caracterización casi-espectral, y afirma que un grafo es distancia-regular si, y sólo si, su exceso espectral (una cantidad calculable a partir de su matriz de adyacencia) es igual a su exceso medio (el número medio de vértices a distancia máxima de cada vértice).Tue, 12 May 2015 11:41:00 GMThttp://hdl.handle.net/2117/278942015-05-12T11:41:00ZFiol Mora, Miquel ÀngelnoGrafo distancia-regular, caracterización combinatoria, caracterización algebraica, teorema del exceso espectralLos grafos distancia-regulares aparecen a menudo en el estudio de es-
tructuras matemáticas con un alto grado de simetría y/o regularidad. Un ejemplo bien conocido de tales grafos son los esqueletos de los sólidos platónicos. Desde que fueron propuestos por Norman Biggs, los grafos distancia-regulares han sido caracterizados por numerosos resultados, tanto de carácter combinatorio como algebraico. Como ejemplo del primer caso, sabemos que un grafo es distancia-regular si, y sólo si, el número de caminos de una longitud dada entre dos vértices sólo depende de la distancia entre dichos vértices. En esta charla se van a presentar y comparar las diferentes caracterizaciones conocidas, tanto las más clásicas como las que han sido recientemente descubiertas por el conferenciante y algunos de sus colaboradores. Entre las últimas, cabe destacar el que ya es conocido en la literatura com el `teorema del exceso espectral’. Este resultado puede considerarse como una caracterización casi-espectral, y afirma que un grafo es distancia-regular si, y sólo si, su exceso espectral (una cantidad calculable a partir de su matriz de adyacencia) es igual a su exceso medio (el número medio de vértices a distancia máxima de cada vértice).An interlacing approach for bounding the sum of Laplacian eigenvalues of graphs
http://hdl.handle.net/2117/27893
Title: An interlacing approach for bounding the sum of Laplacian eigenvalues of graphs
Authors: Abiad, Aida; Fiol Mora, Miquel Àngel; Haemers, Willem H.; Perarnau Llobet, Guillem
Abstract: We apply eigenvalue interlacing techniques for obtaining lower and upper
bounds for the sums of Laplacian eigenvalues of graphs, and characterize equality.
This leads to generalizations of, and variations on theorems by Grone, and Grone &
Merris. As a consequence we obtain inequalities involving bounds for some well-known
parameters of a graph, such as edge-connectivity, and the isoperimetric number.Tue, 12 May 2015 11:31:57 GMThttp://hdl.handle.net/2117/278932015-05-12T11:31:57ZAbiad, Aida; Fiol Mora, Miquel Àngel; Haemers, Willem H.; Perarnau Llobet, GuillemnoLaplacian matrix, eigenvalue interlacing, edge-connectivity, isoperimetric numberWe apply eigenvalue interlacing techniques for obtaining lower and upper
bounds for the sums of Laplacian eigenvalues of graphs, and characterize equality.
This leads to generalizations of, and variations on theorems by Grone, and Grone &
Merris. As a consequence we obtain inequalities involving bounds for some well-known
parameters of a graph, such as edge-connectivity, and the isoperimetric number.Some results on the structure of multipoles in the study of snarks
http://hdl.handle.net/2117/27888
Title: Some results on the structure of multipoles in the study of snarks
Authors: Fiol Mora, Miquel Àngel; Vilaltella Castanyer, Joan
Abstract: Multipoles are the pieces we obtain by cutting some edges of a cubic graph in one or more points. As a result of the cut, a multipole M has vertices attached to a dangling edge with one free end, and isolated edges with two free ends. We refer to such free ends as semiedges, and to isolated edges as free edges. Every 3-edge-coloring of a multipole induces a coloring or state of its semiedges, which satisfies the Parity Lemma. Multipoles have been extensively used in the study of snarks, that is, cubic graphs which are not 3-edge-colorable. Some results on the states and structure of the so-called color complete and color closed multipoles are presented. In particular, we give lower and upper linear bounds on the minimum order of a color complete multipole, and compute its exact number of states. Given two multipoles M1 and M2 with the same number of semiedges, we say that M1 is reducible to M2 if the state set of M2 is a non-empty subset of the state set of M1 and M2 has less vertices than M1. The function v(m) is defined as the maximum number of vertices of an irreducible multipole with rn semiedges. The exact values of v(m) are only known for m <= 5. We prove that tree and cycle multipoles are irreducible and, as a byproduct, that v(m) has a linear lower bound.Tue, 12 May 2015 10:08:14 GMThttp://hdl.handle.net/2117/278882015-05-12T10:08:14ZFiol Mora, Miquel Àngel; Vilaltella Castanyer, Joannocubic graph, edge-coloring, snark, multipole, Parity Lemma, states, color complete, color closed, separable, irreducible, tree, cycle, linear recurrence, GRAPHSMultipoles are the pieces we obtain by cutting some edges of a cubic graph in one or more points. As a result of the cut, a multipole M has vertices attached to a dangling edge with one free end, and isolated edges with two free ends. We refer to such free ends as semiedges, and to isolated edges as free edges. Every 3-edge-coloring of a multipole induces a coloring or state of its semiedges, which satisfies the Parity Lemma. Multipoles have been extensively used in the study of snarks, that is, cubic graphs which are not 3-edge-colorable. Some results on the states and structure of the so-called color complete and color closed multipoles are presented. In particular, we give lower and upper linear bounds on the minimum order of a color complete multipole, and compute its exact number of states. Given two multipoles M1 and M2 with the same number of semiedges, we say that M1 is reducible to M2 if the state set of M2 is a non-empty subset of the state set of M1 and M2 has less vertices than M1. The function v(m) is defined as the maximum number of vertices of an irreducible multipole with rn semiedges. The exact values of v(m) are only known for m <= 5. We prove that tree and cycle multipoles are irreducible and, as a byproduct, that v(m) has a linear lower bound.Approximate results for rainbow labelings
http://hdl.handle.net/2117/27843
Title: Approximate results for rainbow labelings
Authors: Lladó Sánchez, Ana M.
Description: Article de recercaFri, 08 May 2015 11:21:05 GMThttp://hdl.handle.net/2117/278432015-05-08T11:21:05ZLladó Sánchez, Ana M.noOn star-forest ascending subgraph decomposition
http://hdl.handle.net/2117/27841
Title: On star-forest ascending subgraph decomposition
Authors: Aroca Farrerons, José María; Lladó Sánchez, Ana M.Fri, 08 May 2015 11:15:42 GMThttp://hdl.handle.net/2117/278412015-05-08T11:15:42ZAroca Farrerons, José María; Lladó Sánchez, Ana M.noDecomposing almost complete graphs by random trees
http://hdl.handle.net/2117/27840
Title: Decomposing almost complete graphs by random trees
Authors: Lladó Sánchez, Ana M.Fri, 08 May 2015 11:13:27 GMThttp://hdl.handle.net/2117/278402015-05-08T11:13:27ZLladó Sánchez, Ana M.noMagic coverings and the Kronecker product
http://hdl.handle.net/2117/27818
Title: Magic coverings and the Kronecker product
Authors: López Masip, Susana Clara; Muntaner Batle, Francesc Antoni; Rius Font, Miquel
Abstract: In this paper we study a relationship existing among (super) magic coverings and the well known Kronecker product of matrices. We also introduce the concept of Z(n)-property for digraphs in order to study this relation mentioned before. The results obtained in this paper can also be applied to construct S-magic partitions.Thu, 07 May 2015 11:53:47 GMThttp://hdl.handle.net/2117/278182015-05-07T11:53:47ZLópez Masip, Susana Clara; Muntaner Batle, Francesc Antoni; Rius Font, Miquelnomagic covering, super magic covering, Kronecker productIn this paper we study a relationship existing among (super) magic coverings and the well known Kronecker product of matrices. We also introduce the concept of Z(n)-property for digraphs in order to study this relation mentioned before. The results obtained in this paper can also be applied to construct S-magic partitions.On perfect and quasiperfect domination in graphs
http://hdl.handle.net/2117/27709
Title: On perfect and quasiperfect domination in graphs
Authors: Cáceres, José; Hernando Martín, María del Carmen; Mora Giné, Mercè; Pelayo Melero, Ignacio Manuel; Puertas, M LuzMon, 04 May 2015 10:26:03 GMThttp://hdl.handle.net/2117/277092015-05-04T10:26:03ZCáceres, José; Hernando Martín, María del Carmen; Mora Giné, Mercè; Pelayo Melero, Ignacio Manuel; Puertas, M LuznoGlobal location-domination in graphs
http://hdl.handle.net/2117/27680
Title: Global location-domination in graphs
Authors: Hernando Martín, María del Carmen; Mora Giné, Mercè; Pelayo Melero, Ignacio Manuel
Abstract: A dominating set S of a graph G is called
locating-dominating, LD-setfor short, if every vertex v not in S is uniquely determined by the set of neighbors of v
belonging to S. Locating-dominating sets of minimum cardinality are called LD-codes and the cardinality of an LD-code is the
location-domination number (G). An LD-set
S of a graph G is global if it is an LD-set of both G and its complement G. The
global location-domination number g(G) is the minimum cardinality of a global LD-set of
G. In this work,we give some relations between locating-dominating sets and the location-domination number in a graph and its complement
Description: Domination, Global domination, Locating domination, Complement graph, Block-cactus, TreesThu, 30 Apr 2015 08:12:31 GMThttp://hdl.handle.net/2117/276802015-04-30T08:12:31ZHernando Martín, María del Carmen; Mora Giné, Mercè; Pelayo Melero, Ignacio ManuelnoA dominating set S of a graph G is called
locating-dominating, LD-setfor short, if every vertex v not in S is uniquely determined by the set of neighbors of v
belonging to S. Locating-dominating sets of minimum cardinality are called LD-codes and the cardinality of an LD-code is the
location-domination number (G). An LD-set
S of a graph G is global if it is an LD-set of both G and its complement G. The
global location-domination number g(G) is the minimum cardinality of a global LD-set of
G. In this work,we give some relations between locating-dominating sets and the location-domination number in a graph and its complementLinearly dependent vectorial decomposition of clutters
http://hdl.handle.net/2117/27557
Title: Linearly dependent vectorial decomposition of clutters
Authors: Martí Farré, Jaume
Abstract: This paper deals with the question of completing a monotone increas- ing family of subsets G of a finite set ¿ to obtain the linearly dependent subsets of a family of vectors of a vector space. Specifically, we demonstrate that such vec- torial completions of the family of subsets G exist and, in addition, we show that the minimal vectorial completions of the family G provide a decomposition of the clutter ¿ of the inclusion-minimal elements of G . The computation of such vectorial decomposition of clutters is also discussed in some casesFri, 24 Apr 2015 07:44:16 GMThttp://hdl.handle.net/2117/275572015-04-24T07:44:16ZMartí Farré, JaumenoClutter, Antichain, Hypergraph, Matroid, DecompositionThis paper deals with the question of completing a monotone increas- ing family of subsets G of a finite set ¿ to obtain the linearly dependent subsets of a family of vectors of a vector space. Specifically, we demonstrate that such vec- torial completions of the family of subsets G exist and, in addition, we show that the minimal vectorial completions of the family G provide a decomposition of the clutter ¿ of the inclusion-minimal elements of G . The computation of such vectorial decomposition of clutters is also discussed in some casesLinearly dependent vectorial decomposition of clutters
http://hdl.handle.net/2117/27361
Title: Linearly dependent vectorial decomposition of clutters
Authors: Martí Farré, Jaume
Abstract: This paper deals with the question of completing a monotone increasing family of
subsets of a finite set
to obtain the linearly dependent subsets of a family of
vectors of a vector space. Specifically, we demonstrate that such vectorial completions
of the family of subsets ¿ exist and, in addition, we show that the minimal
vectorial completions of the family ¿ provide a decomposition of the clutter of the
inclusion-minimal elements of ¿. The computation of such vectorial decomposition
of clutters is also discussed in some cases.Wed, 15 Apr 2015 15:51:42 GMThttp://hdl.handle.net/2117/273612015-04-15T15:51:42ZMartí Farré, JaumenoClutter, Antichain, Hypergraph, Matroid, Decomposition.This paper deals with the question of completing a monotone increasing family of
subsets of a finite set
to obtain the linearly dependent subsets of a family of
vectors of a vector space. Specifically, we demonstrate that such vectorial completions
of the family of subsets ¿ exist and, in addition, we show that the minimal
vectorial completions of the family ¿ provide a decomposition of the clutter of the
inclusion-minimal elements of ¿. The computation of such vectorial decomposition
of clutters is also discussed in some cases.Preface special issue: Graph Spectra in Computer Science
http://hdl.handle.net/2117/27278
Title: Preface special issue: Graph Spectra in Computer Science
Authors: Comellas Padró, Francesc de Paula
Abstract: Preface to the special issue of Discrete Applied Mathematics with titleMon, 13 Apr 2015 11:21:25 GMThttp://hdl.handle.net/2117/272782015-04-13T11:21:25ZComellas Padró, Francesc de PaulanoGraph spectra, Complex networksPreface to the special issue of Discrete Applied Mathematics with title