Análisis demográficos de la población ovina segureña, como base para el desarrollo de su esquema de selección

La raza ovina Segureña originariamente procede de la cabecera del río Segura, distribuyéndose en la mayor parte de las estribaciones montañosas del Sudeste de España, donde confluyen las provincias de Almería, Granada, Jaén, Albacete y Región de Murcia. Su producción básica es la carne, obteniéndose corderos de elevada calidad con altos rendimientos en matadero. La leche se destina exclusivamente a la cría de la descendencia y la producción de lana es completamente marginal. Según la Orden Ministerial de fecha 12-09-1985 se aprueba definitivamente la reglamentación específica del libro genealógico y de comprobación de rendimientos de la raza Segureña. En la actualidad los censos de la raza superan la cifra de 1.300.000 ovejas de las cuales algo más de 120.000 ejemplares, es decir, en torno al 9,6% del total de la población, se encuentran inscritos en el libro genealógico de la raza. A día de hoy el esquema de selección de la raza ovina Segureña se encuentra a pleno rendimiento y por ello se hace necesario conocer la estructura poblacional de la misma, a la hora de tomar decisiones de interés. En el presente trabajo se describen los tamaños efectivos de la población incluida en la asociación de criadores. Del mismo modo se establece la pirámide de edades total y por núcleos, como paso previo para el cálculo de sus intervalos generacionales. Por supuesto se incluyen los censos totales y parciales por localización y por sexo para una mejor descripción de la población

Uso de modelos no lineales para el ajuste de la curva de crecimiento de corderos segureños a la edad de sacrificio

El objetivo de este trabajo fue estudiar el patrón de crecimiento de corderos segureños desde el nacimiento a la edad de sacrificio establecida, según los criterios del esquema de selección de la raza, a los 70 días de vida; todo ello con la finalidad de predecir algunas características de esos modelos para evaluar los desarrollos corporales de machos y hembras. Para el ajuste global de las curvas de crecimiento se utilizaron tres funciones matemáticas, que fueron la de Compenz, Van Berlalanffy y la curva logística. La base de información utilizada constaba de un total de 25.483 pesadas realizadas en el Núcleo de control de rendimientos entre los años comprendidos entre 1998 y 2004. Para el ajuste de los modelos se utilizó el procedimiento NLIN de SAS. Los modelos utilizados independientemente del sexo del cordero nos proporcionaron una buena calidad de ajuste a los pesos para ambos sexos, indicando que las hembras alcanzan la madurez en edades más precoces, mientras que los machos, presentan un peso adulto más elevado. Para los controles efectuados en ambos sexos el modelo que obtuvo el mejor ajuste (menor valor de Cuadrado Medio del Error) fue el correspondiente a la curva logística

Imperfect and askew: A review of asymmetric genitalia in araneomorph spiders (Araneae: Araneomorphae)

Bilateral asymmetry in the genitalia is a rare but widely dispersed phenomenon in the animal tree of life. In arthropods, occurrences vary greatly from one group to another and there seems to be no common explanation for all the independent origins. In spiders, genital asymmetry appears to be especially rare. Most known species show almost perfectly symmetrical genitals with the right and left sides being mirror images of each other. However, some examples of asymmetric genitalia have been studied and many other reports are scattered in the taxonomic literature. Based on a broad literature survey, we found several species in thirteen families with evidence of genital asymmetry, mostly expressed only in females. Our review suggests that spider genital asymmetries, although rare, are more common than previously thought and taxonomic descriptions and illustrations are a useful but not entirely reliable tool for studying them. Here we also report on directional asymmetry in the liocranid spider Teutamus politus, the first known case of morphologically asymmetric male genitals in Entelegynae spiders. Generalities, evolution and categorization of asymmetry in spiders are further discussed.Animal science

European and Asian contribution to the genetic diversity of mainland South American chickens

Chickens (Gallus gallus domesticus) from the Americas have long been recognized as descendants of European chickens, transported by early Europeans since the fifteenth century. However, in recent years, a possible pre-Columbian introduction of chickens to South America by Polynesian seafarers has also been suggested. Here, we characterize the mitochondrial control region genetic diversity of modern chicken populations from South America and compare this to a worldwide dataset in order to investigate the potential maternal genetic origin of modern-day chicken populations in South America. The genetic analysis of newly generated chicken mitochondrial control region sequences from South America showed that the majority of chickens from the continent belong to mitochondrial haplogroup E. The rest belongs to haplogroups A, B and C, albeit at very low levels. Haplogroup D, a ubiquitous mitochondrial lineage in Island Southeast Asia and on Pacific Islands is not observed in continental South America. Modern-day mainland South American chickens are, therefore, closely allied with European and Asian chickens. Furthermore, we find high levels of genetic contributions from South Asian chickens to those in Europe and South America. Our findings demonstrate that modern-day genetic diversity of mainland South American chickens appear to have clear European and Asian contributions, and less so from Island Southeast Asia and the Pacific Islands. Furthermore, there is also some indication that South Asia has more genetic contribution to European chickens than any other Asian chicken populations.Michael B. Herrera, Spiridoula Kraitsek, Jose A. Alcalde, Daniel Quiroz .... Vicki Thomson ... Jeremy J. Austin ... et al

Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results

Jet size dependence of single jet suppression in lead-lead collisions at sqrt(s(NN)) = 2.76 TeV with the ATLAS detector at the LHC

Measurements of inclusive jet suppression in heavy ion collisions at the LHC provide direct sensitivity to the physics of jet quenching. In a sample of lead-lead collisions at sqrt(s) = 2.76 TeV corresponding to an integrated luminosity of approximately 7 inverse microbarns, ATLAS has measured jets with a calorimeter over the pseudorapidity interval |eta| < 2.1 and over the transverse momentum range 38 < pT < 210 GeV. Jets were reconstructed using the anti-kt algorithm with values for the distance parameter that determines the nominal jet radius of R = 0.2, 0.3, 0.4 and 0.5. The centrality dependence of the jet yield is characterized by the jet "central-to-peripheral ratio," Rcp. Jet production is found to be suppressed by approximately a factor of two in the 10% most central collisions relative to peripheral collisions. Rcp varies smoothly with centrality as characterized by the number of participating nucleons. The observed suppression is only weakly dependent on jet radius and transverse momentum. These results provide the first direct measurement of inclusive jet suppression in heavy ion collisions and complement previous measurements of dijet transverse energy imbalance at the LHC.Comment: 15 pages plus author list (30 pages total), 8 figures, 2 tables, submitted to Physics Letters B. All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HION-2011-02

Measurement of the polarisation of W bosons produced with large transverse momentum in pp collisions at sqrt(s) = 7 TeV with the ATLAS experiment

This paper describes an analysis of the angular distribution of W->enu and W->munu decays, using data from pp collisions at sqrt(s) = 7 TeV recorded with the ATLAS detector at the LHC in 2010, corresponding to an integrated luminosity of about 35 pb^-1. Using the decay lepton transverse momentum and the missing transverse energy, the W decay angular distribution projected onto the transverse plane is obtained and analysed in terms of helicity fractions f0, fL and fR over two ranges of W transverse momentum (ptw): 35 < ptw < 50 GeV and ptw > 50 GeV. Good agreement is found with theoretical predictions. For ptw > 50 GeV, the values of f0 and fL-fR, averaged over charge and lepton flavour, are measured to be : f0 = 0.127 +/- 0.030 +/- 0.108 and fL-fR = 0.252 +/- 0.017 +/- 0.030, where the first uncertainties are statistical, and the second include all systematic effects.Comment: 19 pages plus author list (34 pages total), 9 figures, 11 tables, revised author list, matches European Journal of Physics C versio

Observation of a new chi_b state in radiative transitions to Upsilon(1S) and Upsilon(2S) at ATLAS

The chi_b(nP) quarkonium states are produced in proton-proton collisions at the Large Hadron Collider (LHC) at sqrt(s) = 7 TeV and recorded by the ATLAS detector. Using a data sample corresponding to an integrated luminosity of 4.4 fb^-1, these states are reconstructed through their radiative decays to Upsilon(1S,2S) with Upsilon->mu+mu-. In addition to the mass peaks corresponding to the decay modes chi_b(1P,2P)->Upsilon(1S)gamma, a new structure centered at a mass of 10.530+/-0.005 (stat.)+/-0.009 (syst.) GeV is also observed, in both the Upsilon(1S)gamma and Upsilon(2S)gamma decay modes. This is interpreted as the chi_b(3P) system.Comment: 5 pages plus author list (18 pages total), 2 figures, 1 table, corrected author list, matches final version in Physical Review Letter

Search for displaced vertices arising from decays of new heavy particles in 7 TeV pp collisions at ATLAS

We present the results of a search for new, heavy particles that decay at a significant distance from their production point into a final state containing charged hadrons in association with a high-momentum muon. The search is conducted in a pp-collision data sample with a center-of-mass energy of 7 TeV and an integrated luminosity of 33 pb^-1 collected in 2010 by the ATLAS detector operating at the Large Hadron Collider. Production of such particles is expected in various scenarios of physics beyond the standard model. We observe no signal and place limits on the production cross-section of supersymmetric particles in an R-parity-violating scenario as a function of the neutralino lifetime. Limits are presented for different squark and neutralino masses, enabling extension of the limits to a variety of other models.Comment: 8 pages plus author list (20 pages total), 8 figures, 1 table, final version to appear in Physics Letters