On global location-domination in graphs

A dominating set $S$ of a graph $G$ is called locating-dominating, LD-set for 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 $\lambda(G)$. An LD-set $S$ of a graph $G$ is global if it is an LD-set of both $G$ and its complement $\overline{G}$. The global location-domination number $\lambda_g(G)$ 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.Comment: 15 pages: 2 tables; 8 figures; 20 reference

Extremal Graph Theory for Metric Dimension and Diameter

A set of vertices $S$ \emph{resolves} a connected graph $G$ if every vertex is uniquely determined by its vector of distances to the vertices in $S$. The \emph{metric dimension} of $G$ is the minimum cardinality of a resolving set of $G$. Let $\mathcal{G}_{\beta,D}$ be the set of graphs with metric dimension $\beta$ and diameter $D$. It is well-known that the minimum order of a graph in $\mathcal{G}_{\beta,D}$ is exactly $\beta+D$. The first contribution of this paper is to characterise the graphs in $\mathcal{G}_{\beta,D}$ with order $\beta+D$ for all values of $\beta$ and $D$. Such a characterisation was previously only known for $D\leq2$ or $\beta\leq1$. The second contribution is to determine the maximum order of a graph in $\mathcal{G}_{\beta,D}$ for all values of $D$ and $\beta$. Only a weak upper bound was previously known

Nordhaus-Gaddum bounds for locating domination

A dominating set S of graph G is called metric-locating-dominating if it is also locating, that is, if every vertex v is uniquely determined by its vector of distances to the vertices in S. If moreover, every vertex v not in S is also uniquely determined by the set of neighbors of v belonging to S, then it is said to be locating-dominating. Locating, metric-locating-dominating and locating-dominating sets of minimum cardinality are called b-codes, e-codes and l-codes, respectively. A Nordhaus-Gaddum bound is a tight lower or upper bound on the sum or product of a parameter of a graph G and its complement G. In this paper, we present some Nordhaus-Gaddum bounds for the location number b, the metric-location-number e and the location-domination number l. Moreover, in each case, the graph family attaining the corresponding bound is characterized.Comment: 7 pages, 2 figure

Plan inicial, progresos explícitos y evaluación de una trama de feedforwarding sobre campus virtual en una asignatura de matemáticas

[EN] This paper presents the work carried out during the last academic years by a team of teachers from the Universitat Politècnica de Catalunya -Barcelona Tech (UPC), with the aim of clarifying a set of advantages of a formative and individualized feed-forward evaluation causing reflection - action, forging compromise between student and professors, being not restricted to the truefalse items, offering a quick feedback and guiding. The effort has been focused on Mathematics, during the first semester of the degree in agricultural engineering. This initiative offers a number of exams to the students, in the form of questionnaires, first with and then without feedback, to enliven learning. Students have first considered a test with repeated feedback in order to respond properly to a set of questions and then they have been faced a similar test without feedback. It has been used a support from ICT, in order to observe various profits, focusing on its contribution in terms of improvement in the assessment, the level of the use of the resource by the students, their loyalty and achieving benefits. About two hundred students have participated e[ES] La comunicación recoge el trabajo, por segundo año, de profesores de la Universitat Politècnica de Catalunya (UPC) para aclarar ventajas de una evaluación formativa "feedforwarding”, que cause reflexión – acción, que esté adecuadamente personalizada, que forje compromiso entre las poblaciones estudiantil y docente, que no se circunscriba a un "correcto-incorrecto", que realimente con rapidez y que tutele. El afán ha incidido, y reincidido, sobre "Matemáticas" del primer cuatrimestre de grados en ingeniería. Han sido propuestos a los alumnos unos exámenes, en forma de cuestionarios, con y sin realimentación, para avivar el aprendizaje. Los estudiantes han considerado primero un examen con realimentación repetida hasta responder apropiadamente unas cuestiones para, después, enfrentarse a otro análogo sin realimentación. Ha sido utilizado un sostén de tecnologías de la información y la comunicación, accediendo a examinar provechos de la labor, centrándose sobre todo en su aporte en términos de mejora en la evaluación, de empleo del recurso por los alumnos, de su fidelización y de logro de beneficios. Cada año ha habido una actuación sobre unos dos centenares de estudiantes, con pares de exámenes formados con apoyo de WIRIS (cada par ligado a un contenido temático), usándose Moodle.Fabregat Fillet, J.; Pelayo, I. (2016). Plan inicial, progresos explícitos y evaluación de una trama de feedforwarding sobre campus virtual en una asignatura de matemáticas. En In-Red 2016. II Congreso nacional de innovación educativa y docencia en red. Editorial Universitat Politècnica de València. https://doi.org/10.4995/INRED2016.2016.4404OC

Many-task computing on many-core architectures

Many-Task Computing (MTC) is a common scenario for multiple parallel systems, such as cluster, grids, cloud and supercomputers, but it is not so popular in shared memory parallel processors. In this sense and given the spectacular growth in performance and in number of cores integrated in many-core architectures, the study of MTC on such architectures is becoming more and more relevant. In this paper, authors present what are those programming mechanisms to take advantages of such massively parallel features for the particular target of MTC. Also, the hardware features of the two dominant many-core platforms (NVIDIA's GPUs and Intel Xeon Phi) are also analyzed for our specific framework. Given the important differences in terms of hardware and software in our two many-core platforms, we have considered different strategies based on CUDA (for GPUs) and OpenMP (for Intel Xeon Phi). We carried out several test cases based on an appropriate and widely studied problem for benchmarking as matrix multiplication. Essentially, this study consisted of comparing the time consumed for computing in parallel several tasks one by one (the whole computational resources are used just to compute one task at a time) with the time consumed for computing in parallel the same set of tasks simultaneously (the whole computational resources are used for computing the set of tasks at very same time). Finally, we compared both software-hardware scenarios to identify the most relevant computer features in each of our many-core architectures

A common mechanism of defective channel trafficking underlying DFNA2 hearing loss result in different cell surface expression levels of KCNQ4 mutants

KCNQ4 mutations underlie DFNA2, a subtype of autosomal dominant hearing loss. We had previously identified the pore-region p.G296S mutation that impaired channel activity in two manners: it greatly reduced surface expression and abolished channel function. Moreover, G296S mutant exerted a strong dominant-negative effect on potassium currents by reducing the channel expression at the cell surface representing the first study to identify a trafficking-dependent dominant mechanism for the loss of KCNQ4 channel function in DFNA2. Here, we have investigated the pathogenic mechanism associated with all the described KCNQ4 mutations (F182L, W242X, E260K, D262V, L274H, W276S, L281S, G285C, G285S and G321S) that are located in different domains of the channel protein. F182L mutant showed a wild type-like cell-surface distribution in transiently transfected NIH3T3 fibroblasts and the recorded currents in Xenopus oocytes resembled those of the wild-type. The remaining KCNQ4 mutants abolished potassium currents, but displayed distinct levels of defective cell-surface expression in NIH3T3 as quantified by flow citometry. Co-localization studies revealed these mutants were retained in the ER, unless W242X, which showed a clear co-localization with Golgi apparatus. Interestingly, this mutation results in a truncated KCNQ4 protein at the S5 transmembrane domain, before the pore region, that escapes the protein quality control in the ER but does not reach the cell surface at normal levels. Currently we are investigating the trafficking behaviour and electrophysiological properties of several KCNQ4 truncated proteins artificially generated in order to identify specific motifs involved in channel retention/exportation. Altogether, our results indicate that a defect in KCNQ4 trafficking is the common mechanism underlying DFNA

Cytomegalovirus erosive gastritis in a healthy infant: update about a case

El citomegalovirus es un virus ADN de la familia Herpesviridae que puede afectar al tubo digestivo. Dentro de éste, las dianas de afectación suelen ser el colon, el esófago y el estómago. Se ha descrito ampliamente su asociación con el síndrome de Ménétrier (hiperplasia foveolar con pérdida de proteínas), si bien también puede producir cuadros de gastritis erosiva. En el presente artículo se describe un caso de gastritis erosiva en una lactante sana de 4 meses de edad, que se inició en forma de hemorragia digestiva alta. A partir de este caso, se lleva a cabo una puesta al día de este subgrupo de infecciones por citomegalovirusCytomegalovirus is a DNA Herpesviridae family which can affect the digestive tract. From the standpoint of the stomach, has been widely described his association with Ménétrier syndrome (foveolar hyperplasia with protein-losing) but can also produce erosive gastritis. This article describes a case of erosive gastritis in a healthy 4 months infant which debuted as upper gastrointestinal bleeding. In addition we perform an update of this subgroup of cytomegalovirus infection

Patterns of helminth infection in Kenyan elephant populations

Background: The dynamics of helminth infection in African elephant populations are poorly known. We examined the efects of age, sex, social structure and the normalized diference vegetation index (NDVI) as primary drivers of infection patterns within and between elephant populations. Methods: Coprological methods were used to identify helminths and determine infection patterns in distinct elephant populations in Maasai Mara National Reserve, Tsavo East National Park, Amboseli National Park and LaikipiaSamburu Ecosystem. Gaussian fnite mixture cluster analyses of egg dimensions were used to classify helminth eggs according to genera. Generalized linear models (GLM) and Chi-square analyses were used to test for variation in helminth infection patterns and to identify drivers in elephant populations. Results: Helminth prevalence varied signifcantly between the studied populations. Nematode prevalence (96.3%) was over twice as high as that of trematodes (39.1%) in elephants. Trematode prevalence but not nematode prevalence varied between populations. Although we found no associations between helminth infection and elephant social groups (male vs family groups), the median helminth egg output (eggs per gram, epg) did vary between social groups: family groups had signifcantly higher median epg than solitary males or males in bachelor groups. Young males in mixed sex family groups had lower epg than females when controlling for population and age; these differences, however, were not statistically signifcant. The average NDVI over a three-month period varied between study locations. Cluster analyses based on egg measurements revealed the presence of Protofasciola sp., Brumptia sp., Murshidia sp., Quilonia sp. and Mammomonogamus sp. GLM analyses showed that the mean epg was positively infuenced by a three-month cumulative mean NDVI and by social group; female social groups had higher epg than male groups. GLM analyses also revealed that epg varied between elephant populations: Samburu-Laikipia elephants had a higher and Tsavo elephants a lower epg than Amboseli elephants. Conclusions: Elephants had infection patterns characterized by within- and between-population variation in prevalence and worm burden. Sociality and NDVI were the major drivers of epg but not of helminth prevalence. Gastrointestinal parasites can have a negative impact on the health of wild elephants, especially during resource scarcity. Thus, our results will be important when deciding intervention strategies.This research was funded by the Kenya Wildlife Service and the Department of Animal Pathology, Veterinary Faculty, University of Santiago de Compostela, Lugo, SpainS