Datos sobre la estructura poblacional de Arvicola Sapidus Miller, 1908 (Rodentia: Arvicolidae) del Delta del Ebro

S'aporten dades sobre l'estructura poblacional d'Arvicola sapidus del delta de l'Ebre, segons el mes de captura, l'edat relativa i la relació de sexes. La mostra estudiada ha estat de 135 exemplars (75 dd, 60 99) capturats entre 1980 i 1984. L'activitat sexual que pot aparèixer ocasionalment al final de la tardor i durant l'hivern determina la presència d'exemplars juvenils i subadults al llarg de tot l'any. Entre gener i maig la població és constituïda fonamentalment per adults. El nombre total de mascles i femelles capturats indica que la relació de sexes no s'allunya significativament de la proporció esperada (1:1). Tot i així, atenent a l'edat relativa s'observen diferències significatives en el nombre de mascles i femelles capturats. Hom discuteix els possibles factors que poden influir en aquest desequilibri sexual.Data on population structure of Arvicola sapidus from the Ebro Delta (Tarragona, Spain), according to the month of capture, relative age and sex ratio, are given. 135 specimens (75 dd, 60 gp) captured between 1980 and 1984 were analyzed. The sexual activity which can appear ocasionally at the end of autumn and during winter determines the presence of juvenile and subadult specimens throughout the whole year. Between January and May the population is constituted fundamentally by adult individuals. The total number of males and females captured indicate that the sex ratio is not significantly different from the expected, 1 :1 ratio. Nevertheless, according to the relative age, significative differences between the number of males and females can be observed. The causes for this sexual unbalance are discussed.Se aportan datos sobre la estructura poblacional de Arvicola sapidus del Delta del Ebro (Tarragona), según el mes de captura, la edad relativa y la relación de sexos. La muestra estudiada ha sido de 135 ejemplares (75 dd, 60 99) capturados entre 1980 y 1984. La actividad sexual que ocasionalmente puede aparecer al final de otoño y durante el invierno determina la presencia de ejemplares juveniles y subadultos a lo largo de todo el año. Entre enero y mayo la población esta constituida fundamentalmente por ejemplares adultos. El número total de machos y hembras capturados indica que la relación de sexos no se aparta significativamente de la proporción esperada (1:1). Sin embargo, atendiendo a la edad relativa se aprecian diferencias significativas en el número de machos y hembras capturados. Se discuten los posibles factores que pueden influir en este desequilibrio sexual

A Bocage Landscape Restricts the Gene Flow of Pest Vole Populations.

The population dynamics of most animal species inhabiting agro-ecosystems may be determined by landscape characteristics, with agricultural intensification and the reduction of natural habitats influencing dispersal and hence limiting gene flow. Increasing landscape complexity would thus benefit many endangered species by providing different ecological niches, but it could also lead to undesired effects in species that can act as crop pests and disease reservoirs. We tested the hypothesis that a highly variegated landscape influences patterns of genetic structure in agricultural pest voles. Ten populations of fossorial water vole, Arvicola scherman, located in a bocage landscape in Atlantic NW Spain were studied using DNA microsatellite markers and a graph-based model. The results showed a strong isolation-by-distance pattern with a significant genetic correlation at smaller geographic scales, while genetic differentiation at larger geographic scales indicated a hierarchical pattern of up to eight genetic clusters. A metapopulation-type structure was observed, immersed in a landscape with a low proportion of suitable habitats. Matrix scale rather than matrix heterogeneity per se may have an important effect upon gene flow, acting as a demographic sink. The identification of sub-populations, considered to be independent management units, allows the establishment of feasible population control efforts in this area. These insights support the use of agro-ecological tools aimed at recreating enclosed field systems when planning integrated managements for controlling patch-dependent species such as grassland voles

Distinguishing nanowire and nanotube formation by the deposition current transients

AbstractHigh aspect ratio Ni nanowires (NWs) and nanotubes (NTs) were electrodeposited inside ordered arrays of self-assembled pores (approximately 50 nm in diameter and approximately 50 μm in length) in anodic alumina templates by a potentiostatic method. The current transients monitored during each process allowed us to distinguish between NW and NT formation. The depositions were long enough for the deposited metal to reach the top of the template and form a continuous Ni film. The overfilling process was found to occur in two steps when depositing NWs and in a single step in the case of NTs. A comparative study of the morphological, structural, and magnetic properties of the Ni NWs and NTs was performed using scanning electron microscopy, X-ray diffraction, and vibrating sample magnetometry, respectively.M. P. Proença and C. T. Sousa are thankful to FCT for the doctoral and postdoctoral grants SFRH/BD/43440/2008 and SFRH/BPD/82010/2011, respectively. J. Ventura acknowledges the financial support through FSE/POPH. M Vázquez thanks the Spanish Ministry of Economia y Competitividad, MEC, under project MAT2010-20798-C05-01. J. P. Araújo also thanks the Fundação Gulbenkian for its financial support within the ‘Programa Gulbenkian de Estímulo à Investigação Científica’. The authors acknowledge the funding from FCT through the Associated Laboratory - IN and project PTDC/FIS/105416/2008.Peer Reviewe

Mammalian comparative genomics reveals epigenetic features associated with genome reshuffling in rodentia

Understanding how mammalian genomes have been reshuffled through structural changes is fundamental to the dynamics of its composition, evolutionary relationships between species and, in the long run, speciation. In this work, we reveal the evolutionary genomic landscape in Rodentia, the most diverse and speciose mammalian order, by whole-genome comparisons of six rodent species and six representative outgroup mammalian species. The reconstruction of the evolutionary breakpoint regions across rodent phylogeny shows an increased rate of genome reshuffling that is approximately two orders of magnitude greater than in other mammalian species here considered. We identified novel lineage and clade-specific breakpoint regions within Rodentia and analyzed their gene content, recombination rates and their relationship with constitutive lamina genomic associated domains, DNase I hypersensitivity sites and chromatin modifications. We detected an accumulation of protein-coding genes in evolutionary breakpoint regions, especially genes implicated in reproduction and pheromone detection and mating. Moreover, we found an association of the evolutionary breakpoint regions with active chromatin state landscapes, most probably related to gene enrichment. Our results have two important implications for understanding the mechanisms that govern and constrain mammalian genome evolution. The first is that the presence of genes related to species-specific phenotypes in evolutionary breakpoint regions reinforces the adaptive value of genome reshuffling. Second, that chromatin conformation, an aspect that has been often overlooked in comparative genomic studies, might play a role in modeling the genomic distribution of evolutionary breakpoints

Rata de agua – Arvicola sapidus Miller, 1908

Mamíferos - Orden Rodentia - Familia Arvicolidae en la Enciclopedia Virtual de Vertebrados Españoles, http://www.vertebradosibericos.org/. Versiones anteriores: 14-10-2004; 3-06-2005; 7-05-2007; 18-04-2008; 28-02-2012A comprehensive review of the natural history of the Southwestern Water Vole Arvicola sapidus in Spain.Peer reviewe

Memòria Digital de Catalunya

Localització: Barcelona, Biblioteca de l'Ateneu Barcelonès, ms. 196Núm. 486 a la cobertaCòpia de representacióAlg. esmenes, amb paper rascat, i cancel·lacióNoms dels actors del repartimentData deduïda d'altres obres dels autorsPaper pautatEl v. dels f. en blancAcotacions de l'autor entre parèntesis i aparts indicats amb l'abreviatura "ap." entre parèntesis a l'inici de els intervencions; acotacions del director d'escena amb el nom d'alg. dels actors i marques en forma de cre