New results on metric-locating-dominating sets of graphs

A dominating set $S$ of a graph is a metric-locating-dominating set if each vertex of the graph is uniquely distinguished by its distances from the elements of $S$, and the minimum cardinality of such a set is called the metric-location-domination number. In this paper, we undertake a study that, in general graphs and specific families, relates metric-locating-dominating sets to other special sets: resolving sets, dominating sets, locating-dominating sets and doubly resolving sets. We first characterize classes of trees according to certain relationships between their metric-location-domination number and their metric dimension and domination number. Then, we show different methods to transform metric-locating-dominating sets into locating-dominating sets and doubly resolving sets. Our methods produce new bounds on the minimum cardinalities of all those sets, some of them involving parameters that have not been related so far.Comment: 13 pages, 3 figure

Independent [1,2]-number versus independent domination number

A [1, 2]-set S in a graph G is a vertex subset such that every vertex not in S has at least one and at most two neighbors in it. If the additional requirement that the set be independent is added, the existence of such sets is not guaranteed in every graph. In this paper we provide local conditions, depending on the degree of vertices, for the existence of independent [1, 2]-sets in caterpillars. We also study the relationship between independent [1, 2]-sets and independent dominating sets in this graph class, that allows us to obtain an upper bound for the associated parameter, the independent [1, 2]-number, in terms of the independent domination number.Peer ReviewedPostprint (published version

New results on metric-locating-dominating sets of graphs

A dominating set S of a graph is a metric-locating-dominating set if each vertex of the graph is uniquely distinguished by its distanc es from the elements of S , and the minimum cardinality of such a set is called the metri c-location- domination number. In this paper, we undertake a study that, in general graphs and specific families, relates metric-locating-dominatin g sets to other special sets: resolving sets, dominating sets, locating-dominating set s and doubly resolving sets. We first characterize classes of trees according to cer tain relationships between their metric-location-domination number and thei r metric dimension and domination number. Then, we show different methods to tran sform metric- locating-dominating sets into locating-dominating sets a nd doubly resolving sets. Our methods produce new bounds on the minimum cardinalities of all those sets, some of them involving parameters that have not been related so farPostprint (published version

INFOPràcticum: i després del grau, què?

Podeu consultar la Vuitena trobada de professorat de Ciències de la Salut completa a: http://hdl.handle.net/2445/66524L'INFOPràcticum és una jornada en que s'organitzen un conjunt d'activitats (xerrades, taula rodona, presentació de pòsters sobre les pràctiques realitzades, etc.), pensades per orientar a l'alumnat de 4t. curs sobre les sortides professionals, i les possibilitats que té de seguir-se formant a l'INEFC. És també el moment en que l'alumnat de 4t. de grau..

Estudi de l'evolució micromorfológica i funcional del trasplantament intestinal experimental

El objetivo de nuestro estudio fue evaluar si el fallo de la función intestinal absortiva observado después del trasplante de intestino delgado se debe a cambios en el tamaño de la superficie epitelial o bien proviene de un fallo en la función celular de los enterocitos. MATERIAL Y MÉTODOSSe realizaron trasplantes de intestino delgado (SBT) en ratas de acuerdo con la técnica de Monchik y Russell. Los animales fueron distribuidos en tres grupos (n=15 cada uno): Grupo A (control): asa simple de Thiry Vella; Grupo B: isotransplante heterotópico LEW-LEW; Grupo C: alotransplante heterotópico LBN-LEW. Se utilizó como solución de preservación Ringer lactato heparinizado a 4º C. Las ratas del grupo C se trataron con Ciclosporina (15mg/kg/24h IM). A los 21 dias del transplante heterotòpico, en 5 animales de cada grupo se realizó un segundo procedimiento quirúrgico para colocar el segmento de intestino transplantado en posición ortotópica. Mediante microscopía òptica y tinción H/E se observó la evolución micromorfológica de la mucosa intestinal, tomando muestras del intestino donante in situ antes de la perfusión y tras el transplante a los 7,14,21 y 36 dias. Estas muestras fueron procesadas mediante un sistema de analisis morfométrico de imagenes para quantificar cambios en el tamaño de las vellosidades en cuanto altura y anchura y asi determinar una posible modificacion en la superficie epitelial absortiva. En las series con transplante ortotópico, las muestras de intestino se estudiaron además por Microscopía Electrónica de Transmisión (TEM). Para determinar la evolución de la función absortiva del intestino transplantado se efectuaron pruebas de absorción de glucosa en los mismos intervalos de tiempo que las biopsias.RESULTADOS El estudio morfométrico muestra una disminución progresiva en la altura de las vellosidades tras el transplante, siendo más pronunciado en el grupo C. Una tendencia al aumento se observó en el ancho de las vellosidades. La superficie epitelial absortiva mostró una tendencia a la reducción, recuperando los valores iniciales tras la interposición ortotópica. Una reducción progresiva significativa de la absorción de glucosa se observó en ambos grupos de animales trasplantados respecto al grupo control. El estudio por TEM mostró la presencia de vacuolas citoplasmáticas en los enterocitos, así como una leve alteración en la morfología de las microvellosidades, mitocondrias y retículo endoplásmico. DISCUSIÓN Y CONCLUSIONES Una alteración de la fisiología celular parece ser la causa del fallo de la función de absorción intestinal después de SBT y este fracaso no dependería del tamaño de la superficie epitelial. Las alteraciones ultraestructurales observadas al TEM sugieren un daño celular grave que podría ser la causa de la insuficiencia absortiva. Pero el origen de estas alteraciones intracelulares sigue siendo desconocido pudiendo provenir tanto del efecto isquemia-reperfusión como de la respuesta inmunológica o de la toxicidad del propio tratamiento inmunosupresor.The aim of our study was to asses if the failure of the absortive intestinal function observed after small bowel transplantation is due either to changes in the size of epithelial surface or caused by a failure in the cellular function of enterocytes.MATERIALS AND METHODSSmall bowel transplants (SBT) were performed in rats according to Monchik and Russell's technique. Animals were distributed into three groups (n=15 each):Group A (control):simple Thiry-Vella loop; Group B:heterotopic isograft LEW-LEW; Group C:heterotopic allograft LBN-LEW. Heparinized lactated Ringer's at 4ºC was a cold preservation solution. Cyclosporine dose 15mg/kg/24h IM was administered to group C rats. At day 21 of the initial surgery, a second operative procedure was carried out on 5 of the transplanted animals of each group to place the transplanted small bowel in orthotopic position.To asses the micromorphology of intestinal mucosa by light microscopy (LM), biopsy specimens of the donor small bowel were taken in situ before perfusion and after transplant at 7,14,21 and 36 days. In those series with orthotopic transplantation bowel samples were studied, in addition, by Transmision Electron Microscopy (TEM).The absortive function of the transplanted bowel was observed by Glucose absorption test performed at same time points of the biopsies. Histomorphometric determinations of size of villus height and width, and total epithelial surface was performed by LM H/E and Image Processing and Analysis System.RESULTSMorphometrical study shows a progressive shortening of villus in both groups of transplanted animals, being more pronounced in the group C at the end of study. A tendency to increase was observed in the villus width. The absorptive epithelial surface showed an initial reduction followed of return to normal state after orthotopical interposition.A significative progressive reduction of glucose absorption was observed in both groups of transplanted animals than in the control group.Study by TEM showed cytoplasmic vacuoles in the absorptive cells. There was also a slight alteration on morphology of microvilli, mitochondries and endoplasmic reticulum.DISCUSSION/CONCLUSIONSAn alteration of cellular physiology underlies the failure of intestinal absorptive function after SBT and this failure does not depend on the size of epithelial surface. The findings of TEM suggest a severe ultrastructural damage could be the cause of cellular absorptive failure, but the cause of this cellular damage remains unkown

Dominating 2-broadcast in graphs: complexity, bounds and extremal graphs

Limited dominating broadcasts were proposed as a variant of dominating broadcasts, where the broadcast function is upper bounded. As a natural extension of domination, we consider dominating 2-broadcasts along with the associated parameter, the dominating 2-broadcast number. We prove that computing the dominating 2-broadcast number is a NP-complete problem, but can be achieved in linear time for trees. We also give an upper bound for this parameter, that is tight for graphs as large as desired.Peer ReviewedPostprint (author's final draft