New constraints on Heavy Neutral Leptons from Super-Kamiokande data

Heavy neutral leptons are predicted in many extensions of the Standard Model with massive neutrinos. If kinematically accessible, they can be copiously produced from kaon and pion decays in atmospheric showers, and subsequently decay inside large neutrino detectors. We perform a search for these long-lived particles using Super-Kamiokande multi-GeV neutrino data and derive stringent limits on the mixing with electron, muon and tau neutrinos as a function of the long-lived particle mass. We also present the limits on the branching ratio versus lifetime plane, which are helpful in determining the constraints in non-minimal models where the heavy neutral leptons have new interactions with the Standard Model.Comment: 6 pages, 4 figures. v2: Minor changes, references added. Version accepted for publication in EPJ

Methodology to reconstruc virtual cities from the past

Postprint (published version

The atlantic side of the iberian peninsula: a hot-spot of novel maternal honey bee diversity

The Iberian Peninsula harbors one the highest mitocondrial DNA (mtDNA) diversity ever reported for honey bee subspecies. This finding is explained not only by the co-occurrence of two divergent evolutionary lineages, western European (lineage M) and African (lineage A), but also by the higher variability of African and western European haplotypes. Indeed, over 36 haplotypes of western European and African ancestry, which form complex networks, have been reported for this area of the honey bee natural range. While studies on the diversity patterns of central and Mediterranean Iberian populations are abundant, the genetic composition of populations inhabiting the Atlantic side was until recently virtually unknown. Using the popular DraI test (PCR amplification and restriction of the intergenic tRNAleu-coxII region) we performed a fine scale genetic survey of the honey bee populations from Portugal. Adding to the 24 previously described African haplotypes, of which 17 are found in the Iberian Peninsula, 13 unreported haplotypes of African ancestry were found in our survey, which represent an addition of 54% of new variation. The fragment sizes ranged from approximately 800 to 1200 bp and the restriction length of the new haplotypes were very distinct from those reported in the literature. To further confirm the novelty of these haplotypes, we sequenced the aforementioned mtDNA region. Herein we present a phylogenetic analysis of these novel haplotypes

Patrón espacial de la variación molecular de Apis mellifera en Gran Canaria y la Gomera (Islas Canarias)

Las islas del Archipiélago Canario presentan condiciones ambientales variables según su altitud, latitud y longitud, lo cual influye en la distribución de los organismos. En relación con la abeja de la miel (Apis mellifera L.), estudios previas realizados por De la Rúa et a I. ( 1998) Y por Padilla-Álvarez et al. (1998), sugieren la existencia en las Islas Canarias de poblaciones que han evolucionado de una forma relativamente aislada y que se han adaptado en cada isla a unas determinadas condiciones ambientales. Las abejas canarias fueron incluí das en un sublinaje de distribución atlántica (AIII) del linaje evolutivo africano, en el cual se circunscriben las poblaciones de abejas de los Archipiélagos Maearonésicos (Islas Azores, Madeira, Islas Salvajes, Islas Canarias y Cabo Verde) y de Portugal. En el presente trabajo se presentan los resultados del estudio de la variabilidad molecular al nivel mitocondrial (ADNmt), de las poblaciones de abejas de la miel en las islas canarias de Gran Canaria y La Gomera mediante el análisis de la región intergénica del ADNmt comprendida entre los genes del ARN transferente de la leucina (ARNtleu) y la subunidad II de la citocromo oxidasa (cox2). Este marcador es adecuado para estimar la diversidad genética y los patrones de diferenciación espacial, en relación con la variedad ambiental existente en las islas de Gran Canaria y La Gomera

Exploring value differences across family firms : The influence of choosing and managing complexity

Altres ajuts: Formation of University Researchers (FPU)Stewardship is considered a distinctive feature of family firms, and it is associated with a set of values, including altruism, collectivism, trust, identification, loyalty and commitment. However, the extent to which these values actually prevail in different types of family firms has not often been explored, especially in relation to the types of complexity found in family firms. In this study, we address this gap in the literature and explore the existence of potential differences among family firms. Additionally, we investigate the possible reasons for these differences with regard to the levels of management complexity in the family firms and the processes related to such complexity, such as succession, pruning and complexity management options. We use a multiple case-study methodology involving 22 long-established family firms in northeast Spain. Based on the empirical results from our dynamic and multidimensional approach, this article primarily contributes to the existing literature by providing a conceptual model of the influence complexity has on values in family firms

Regional tourism competitiveness using the PROMETHEE approach

The competitiveness of tourism destinations is a key issue because it enables destinations to know their position with regard to their competitors. The aim of this paper is threefold: (1) to address the measurement of the competitiveness of tourism destinations at the regional level, (2) to show the suitability of using multi-criteria techniques to measure competitiveness, and (3) to apply the PROMETHEE and GAIA methods within a competitiveness study of eight tourist destinations located in the Northern Region of Portugal. The Metropolitan Area of Porto is the first in the ranking, followed by Cávado and Douro. The results of such an analysis show the comparative strengths and weaknesses of destinations, and allow them to identify their true competitors as well as those other destinations that are most similar to them.info:eu-repo/semantics/publishedVersio

Food aroma mass transport properties in renewable hydrophilic polymers

[EN] The sorption and transport properties of gliadin and chitosan films with respect to four representative food aroma components (ethyl caproate, 1-hexanol, 2-nonanone and α-pinene) have been studied under dry and wet environmental conditions. The partition coefficients (K) of the selected volatiles were also obtained using isooctane and soybean oil as fatty food simulants. The results showed that gliadin and chitosan films have very low capacities for the sorption of volatile compounds, and these capacities are influenced by the nature of the sorbate, the environmental relative humidity and the presence of glycerol as a plasticizer in the polymeric matrix. The volatile compounds also present a low partitioning in the biopolymer film/food stimulant system. Given the low levels of interaction observed with the volatiles, gliadin and chitosan films are of potential interest for the packaging of foods in which aroma is one of the most important quality attributes Highlights ► Sorption kinetics and equilibrium partitioning of food aroma compounds in bioplastics. ► Gliadin and chitosan films show low sorption and partitioning capacities of food aroma compounds. ► Sorption and diffusion depend on volatile chemical structure, film composition and moisture. ► Great potential in packaging of foods in which aroma is an important quality attribute.This research has been supported from the Spanish Ministry of Science and Innovation through the Projects AGL2006-02176, AGL2009-08776 and FUN-C-FOOD Consolider Ingenio. The authors would like to thank A.P. Mac Cabe for critical reading of the manuscript.Balaguer, MP.; Gavara Clemente, R.; Hernández Muñoz, P. (2012). Food aroma mass transport properties in renewable hydrophilic polymers. Food Chemistry. 130(4):814-820. https://doi.org/10.1016/j.foodchem.2011.07.052S814820130

Interplay between symmetry and spin-orbit coupling on graphene nanoribbons

We study the electronic structure of chiral and achiral graphene nanoribbons with symmetric edges, including curvature and spin-orbit effects. Curved ribbons show spin-split bands, whereas flat ribbons present spin-degenerate bands. We show that this effect is due to the breaking of spatial inversion symmetry in curved graphene nanoribbons, while flat ribbons with symmetric edges possess an inversion center, regardless of their having chiral or achiral edges. We find an enhanced edge-edge coupling and a substantial gap in narrow chiral nanoribbons, which is not present in zigzag ribbons of similar width. We attribute these size effects to the mixing of the sublattices imposed by the edge geometry, yielding a behavior of chiral ribbons that is distinct from those with pure zigzag edges. © 2013 American Physical Society.This work has been partially supported by the Spanish Ministries of Science and Innovation (MICINN) and Economy and Competitivity (MINECO) DGES under Grants No. MAT2009-14578-C03-03, No. PIB2010BZ-00512, No. FIS2010-21282-C02-02, No. FIS2011-23713, No.MAT2012-38045-C04-04, and No. FIS2012-33521.Peer Reviewe

Polymorphisms in cytochrome P450 versus cline distribution of evolutionary lineages in Apis mellifera iberiensis

Honey bees (Apis mellifera) are the most prominent and economically important pollinator species worldwide. However, the reported decline of its populations in several regions of the world over the last decades is of concern. The causes are manifold, including the spread of pathogens and parasites, malnutrition and habitat loss, climate change and xenobiotics, especially pesticides. Among the main mechanisms used by insects to cope with the adverse effects of xenobiotics is the metabolic resistance mediated mainly by three superfamilies of enzymes: the cytochrome P450 monooxygenases, the glutathione transferases and the carboxylesterases. We hypothesize that the genetic background influences the sensitivity to pesticides or detoxification capacity of different honey bee populations, ecotypes and subspecies. The Iberian Peninsula provides an interesting scenario to study the genetic variability of the cytochrome P450 genes given the co-occurrence of two clinally distributed evolutionary lineages, as a result of secondary contact. In this study, the genetic variability of six genes of the cytochrome P450 superfamily (CYP6AS3, CYP6AS4, CYP6AS5, CYP6AS7, CYP6AS12 and CYP6AS17) was analyzed in the Iberian honey bee (Apis mellifera iberiensis) to provide more information on the mechanisms of resistance to xenobiotics and to identify the genetic variation involved in local adaptation. Genomic signal of selective sweeps was detected in three genes, of which CYP6AS5 presents the highest number of point mutations under selection, being proposed as a candidate gene to perform gene expression studies. We discuss the correlation between the variability of P450 genes and the distribution of the evolutionary lineages in the Iberian Peninsula. The identification of polymorphisms in these genes promises to shed light on the relationship between diversity and xenobiotic tolerance of A. m. iberiensis.info:eu-repo/semantics/publishedVersio