Aplicaciones de la Teoría de Matrices en Matemática Discreta

Se describen algunas aplicaciones de la teoría de matrices a diversos temas pertenecientes alámbito de la matem\'atica discreta.

Linear and nonlinear terrain deformation maps from a reduced set of interferometric SAR images

In this paper, an advanced technique for the generation of deformation maps using synthetic aperture radar (SAR) data is presented. The algorithm estimates the linear and nonlinear components of the displacement, the error of the digital elevation model (DEM) used to cancel the topographic terms, and the atmospheric artifacts from a reduced set of low spatial resolution interferograms. The pixel candidates are selected from those presenting a good coherence level in the whole set of interferograms and the resulting nonuniform mesh tessellated with the Delauney triangulation to establish connections among them. The linear component of movement and DEM error are estimated adjusting a linear model to the data only on the connections. Later on, this information, once unwrapped to retrieve the absolute values, is used to calculate the nonlinear component of movement and atmospheric artifacts with alternate filtering techniques in both the temporal and spatial domains. The method presents high flexibility with respect to the required number of images and the baselines length. However, better results are obtained with large datasets of short baseline interferograms. The technique has been tested with European Remote Sensing SAR data from an area of Catalonia (Spain) and validated with on-field precise leveling measurements.

Systematic review protocol to define classical IgE-associated diseases from birth to adolescence: the MeDALL study

BACKGROUND: Classical disease phenotypes are mainly based on descriptions of symptoms and the hypothesis that a given pattern of symptoms provides a diagnosis. With refined technologies there is growing evidence that disease expression in patients is much more diverse and subtypes need to be defined to allow a better targeted treatment. One of the aims of the Mechanisms of the Development of Allergy Project (MeDALL,FP7) is to re-define the classical phenotypes of IgE-associated allergic diseases from birth to adolescence, by consensus among experts using a systematic review of the literature and identify possible gaps in research for new disease markers. This paper describes the methods to be used for the systematic review of the classical IgE-associated phenotypes applicable in general to other systematic reviews also addressing phenotype definitions based on evidence. METHODS/DESIGN: Eligible papers were identified by PubMed search (complete database through April 2011). This search yielded 12,043 citations. The review includes intervention studies (randomized and clinical controlled trials) and observational studies (cohort studies including birth cohorts, case-control studies) as well as case series. Systematic and non-systematic reviews, guidelines, position papers and editorials are not excluded but dealt with separately. Two independent reviewers in parallel conducted consecutive title and abstract filtering scans. For publications where title and abstract fulfilled the inclusion criteria the full text was assessed. In the final step, two independent reviewers abstracted data using a pre-designed data extraction form with disagreements resolved by discussion among investigators. DISCUSSION: The systematic review protocol described here allows to generate broad,multi-phenotype reviews and consensus phenotype definitions. The in-depth analysis of the existing literature on the classification of IgE-associated allergic diseases through such a systematic review will 1) provide relevant information on the current epidemiologic definitions of allergic diseases, 2) address heterogeneity and interrelationships and 3) identify gaps in knowledge.

The effects of regional educational policies on school failure in Spain

This paper presents a regional analysis of the effects of educational policies implemented in Spain between 1992 and 2003, focusing specifically on school failure rates. We consider the impact of expenditure per pupil, class size, and pupil-teacher ratio on dropout rates at the end of compulsory education and on the proportion of early school-leavers in the 18-24 year age group. Our results indicate that higher levels of educational expenditure per pupil and lower class sizes and pupil-teacher ratios reduce rates of dropout and early school-leaving (although class-size is not always significant). However, the magnitude of the effects of these variables is small at the average level.

Arqueología de paisajes altimontanos pirenaicos: formas de explotación y usos del medio en época romana en valle del Madriu-Perafita-Claror (Andorra) y en la Sierra del Cadí (Alt Urgell)

long-term cultural history of the Madriu-Perafita-Claror valleys (Andorra) and the Cadí Range (Catalonia) has been investigated thanks to the combination of archaeological surveys and excavation, analysis of written sources, multiproxy alaeoenvironment analysis (pollen, NPP, micro and macro charcoal, sedimentology and geochemistry), and digital technologies such as stereophotogrammetry, multispectral imaging, DGPS and GIS. The project has been designed from a landscape archaeology approach and the study area has been selected due to the suitable setting it provides for a meaningful application of the aforementioned techniques. Consequently, archaeological, historical and palaeoenvironmental data have been all treated as cultural proxies. Their comparison has allowed obtaining not only coherent but also complementary results. The project outcomes show an uninterrupted occupation of these high mountain valleys (2000-2600 m a.s.l.) from the Mesolithic until the present. This human occupation shows strong spatial and chronological variability in human practices ranging from a stable long term group occupation in the Late Neolithic to the diversification of representative practices during the Roman period (metallurgy, pine resin exploitation, charcoal production, pastoralism, etc.). This high diversity of activities leads to complex cultural landscapes in the high Pyrenean areas. The reconstruction of the cultural history at the study areas will allow the development of more sustainable politics for these landscapes management.

Abnormal social behaviors and altered gene expression rates in a mouse model for Potocki-Lupski syndrome.

The Potocki-Lupski syndrome (PTLS) is associated with a microduplication of 17p11.2. Clinical features include multiple congenital and neurobehavioral abnormalities and autistic features. We have generated a PTLS mouse model, Dp(11)17/+, that recapitulates some of the physical and neurobehavioral phenotypes present in patients. Here, we investigated the social behavior and gene expression pattern of this mouse model in a pure C57BL/6-Tyr(c-Brd) genetic background. Dp(11)17/+ male mice displayed normal home-cage behavior but increased anxiety and increased dominant behavior in specific tests. A subtle impairment in the preference for a social target versus an inanimate target and abnormal preference for social novelty (the preference to explore an unfamiliar mouse versus a familiar one) was also observed. Our results indicate that these animals could provide a valuable model to identify the specific gene(s) that confer abnormal social behaviors and that map within this delimited genomic deletion interval. In a first attempt to identify candidate genes and for elucidating the mechanisms of regulation of these important phenotypes, we directly assessed the relative transcription of genes within and around this genomic interval. In this mouse model, we found that candidates genes include not only most of the duplicated genes, but also normal-copy genes that flank the engineered interval; both categories of genes showed altered expression levels in the hippocampus of Dp(11)17/+ mice.

Màrqueting i comunicació aplicats a les organitzacions socials

El marqueting és un element fonamental per al disseny i materialització d' uns serveis i productes adequats a les necessitats deis nostres usuari s. Es tractad' aplicar una metodologia de treball que consta de diversos passos que anirem desenvolupant de forma progressiva. És una guia que posa en ordre la successiva informació que anem recollint sobre el nostre entorn més immediat. Un cop desenvolupat aquest procés de recollida d' informació, tindrem els elements suticients per prendre decisions estrategiques encaminades a definir un servei eficaç a un determinat segment de la població amb unes necessitats concretes.

High-performance payload data handling system for Gaia

Gaia is the most ambitious space astrometry mission currently envisaged and is a technological challenge in all its aspects. We describe a proposal for the payload data handling system of Gaia, as an example of a high-performance, real-time, concurrent, and pipelined data system. This proposal includes the front-end systems for the instrumentation, the data acquisition and management modules, the star data processing modules, and the payload data handling unit. We also review other payload and service module elements and we illustrate a data flux proposal.

Does land titling matter? The role of land property rights in the war on illicit crops in Colombia

This paper analyzes the role of formalization of land property rights in the war against illicit crops in Colombia. We argue that as a consequence of the increase of state presence and visibility during the period of 2000 and 2009, municipalities with a higher level of formalization of their land property rights saw a greater reduction in the area allocated to illicit crops. We hypothesize that this is due to the increased cost of growing illicit crops on formal land compared to informal, and due to the possibility of obtaining more benets in the newly in- stalled institutional environment when land is formalized. We exploit the variation in the level of formalization of land property rights in a set of municipalities that had their rst cadastral census collected in the period of 1994-2000; this selection procedure guarantees reliable data and an unbiased source of variation. Using fixed effects estimators, we found a signicant negative relationship between the level of formalization of land property rights and the number of hectares allocated to coca crops per municipality. These results remain robust through a number of sensitivity analyses. Our ndings contribute to the growing body of evidence on the positive effects of formal land property rights, and e ective policies in the war on drugs in Colombia.

Hacia la arquitectura de la información 3.0: pasado, presente y futuro

La arquitectura de la información (IA), aunque presente en cierta manera desde hace más de 50 años, ha tomado especial relevancia con la llegada de la Web y el aumento de la cantidad de información a nuestro alcance. La disciplina cuenta ya con unos pilares claros, que se fundamentan en los contenidos gestionados pero sobre todo en los usuarios, sin olvidar su contexto. También se identifica una serie de componentes a combinar a la hora de elaborar una IA y una metodología básica. Pero la cantidad de información a nuestro alcance no para de crecer, así que se continúa innovando en nuevas formas de organización, buscadores más eficaces o tecnologías de web semántica que permiten a los ordenadores encargarse de la parte menos creativa de enfrentarse a esa avalancha de información.

Isolation and characterization of Saccharomyces cerevisiae mutants resistant to aculeacin A

Aculeacin A is a lipopeptide that inhibits ,B-glucan synthesis in yeasts. A number of Saccharomyces cerevisiae mutants resistant to this antibiotic were isolated, and four loci (ACRI, ACR2, ACR3, and ACR4) whose products are involved in the sensitivity to aculeacin A of yeast ceils were defined. Mutants containing mutations in the four loci were also resistant to echinocandin B, another member of this lipopeptide family of antibiotics. In contrast, acri, acr3, and acr4 mutants were resistant to papulacandin B (an antibiotic containing a disaccharide linked to two fatty acid chains that also inhibits P-glucan synthesis), but acr2 mutants were susceptible'to this antibiotic. This result defines common and specific steps in the entry and action of aculeacin A and papulacandin B. The analysis of double mutants revealed an epistatic effect of the acr2 mutation on the other three mutations. Cell walls of the four different mutants did not show significant alterations in composition with respect to the parental strain, and in vitro glucan synthase activity was also unaffected. However, cell surface hydrophobicity in three of the mutants was considerably decreased with respect to the parental strain.

Formes d"ocupació d"alta muntanya a la vall de la Vansa (Serra del Cadí - Alt Urgell) i a la vall del Madriu-Perafita-Claror (Andorra): estudi diacrònic de paisatges culturals pirinencs

Els medis d'alta muntanya han estat tradicionalment concebuts com espais naturals, caracteritzats per la marginalitat de les activitats humanes. Tanmateix, en les darreres dècades, diversos projectes d'investigació han posat de manifest que a Europa, l'alta muntanya constitueix un espai humanitzat des d'antic, en molts casos, des del Mesolític. Des d"aquesta nova perspectiva, la muntanya ha passat a constituir un paisatge humanitzat, cultural, modelat al llarg del temps. Els estudis en curs plantegen analitzar aquests espais com a paisatges culturals en totes les seves dimensions, mediambiental i social o humana. En aquest nou context, l"anàlisi del registre arqueològic i de les adaptacions humanes al medi requereix d"una aproximació integral des de l"Arqueologia del Paisatge, la Història Ambiental i la Paleoecologia.

Avances de la fruticultura en México

Las estadísticas oficiales informaron que en 2008 se cultivaron 264 944 ha con valor de la producción de $ 14 741 millones de pesos, en 20 frutales de clima templado; mientras que, en 35 tropicales y subtropicales fue de 1 822748 ha con valor de $ 43 463 millones de pesos. De los 55 frutales, sólo naranjo (Citrus sinensis), mango (Mangifera indica), Aguacate (Persea americana), limón mexicano (C. aurantifolia), banano (Musa acuminata), lima persa (C. latifolia) y manzano (Malus domestica) se cultivan más de 50 000 ha, lo que explica porque es limitada la oferta de frutas en las grandes ciudades (Distrito Federal, Monterrey, Guadalajara, Puebla, Veracruz, entre otras). Considerando que el 79,27% de la superficie plantada con frutales tropicales y subtropicales es de temporal, las densidades de plantación son bajas, la propagación de plantas no se hace en viveros certificados (sólo cítricos), los rendimientos son bajos en comparación con otros países productores. Por otra parte, debido a la falta de técnicos capacitados, en los últimos 28 años la demanda de fruta se ha solucionado incrementando la superficie plantada, pero los rendimientos han disminuido. La presencia de nuevas enfermedades; Huanglongbing, Meleira, Sunblotch, plantean nuevos retos y también posibilidades si utilizamos los avances tecnológicos. La fruticultura es una alternativa viable pero deben utilizar altas densidades, árboles de porte bajo, plantas de origen genético conocido y calidad fitosanitaria probada que permitan tener mayores rendimientos y con ello competitividad.