Population genomics of a predatory mammal reveals patterns of decline and impacts of exposure to toxic toads

Mammal declines across northern Australia are one of the major biodiversity loss events occurring globally. There has been no regional assessment of the implications of these species declines for genomic diversity. To address this, we conducted a species-wide assessment of genomic diversity in the northern quoll (Dasyurus hallucatus), an Endangered marsupial carnivore. We used next generation sequencing methods to genotype 10,191 single nucleotide polymorphisms (SNPs) in 352 individuals from across a 3220-km length of the continent, investigating patterns of population genomic structure and diversity, and identifying loci showing signals of putative selection. We found strong heterogeneity in the distribution of genomic diversity across the continent, characterized by (i) biogeographical barriers driving hierarchical population structure through long-term isolation, and (ii) severe reductions in diversity resulting from population declines, exacerbated by the spread of introduced toxic cane toads (Rhinella marina). These results warn of a large ongoing loss of genomic diversity and associated adaptive capacity as mammals decline across northern Australia. Encouragingly, populations of the northern quoll established on toad-free islands by translocations appear to have maintained most of the initial genomic diversity after 16 years. By mapping patterns of genomic diversity within and among populations, and investigating these patterns in the context of population declines, we can provide conservation managers with data critical to informed decision-making. This includes the identification of populations that are candidates for genetic management, the importance of remnant island and insurance/translocated populations for the conservation of genetic diversity, and the characterization of putative evolutionarily significant units

Measurement of the W+W- Production Cross Section in ppbar Collisions at sqrt(s)=1.96 TeV using Dilepton Events

We present a measurement of the W+W- production cross section using 184/pb of ppbar collisions at a center-of-mass energy of 1.96 TeV collected with the Collider Detector at Fermilab. Using the dilepton decay channel W+W- -> l+l-vvbar, where the charged leptons can be either electrons or muons, we find 17 candidate events compared to an expected background of 5.0+2.2-0.8 events. The resulting W+W- production cross section measurement of sigma(ppbar -> W+W-) = 14.6 +5.8 -5.1 (stat) +1.8 -3.0 (syst) +-0.9 (lum) pb agrees well with the Standard Model expectation.Comment: 8 pages, 2 figures, 2 tables. To be submitted to Physical Review Letter

Asymmetries in the production of Λ0 in 250 GeV/c π±, K± and p–nucleon interactions

AbstractUsing data from Fermilab fixed-target experiment E769, we have measured particle–antiparticle production asymmetries for Λ0 hyperons in 250 GeV/c π±, K± and p–nucleon interactions. The asymmetries are measured as functions of Feynman-x (xF) and pT2 over the ranges −0.12⩽xF⩽0.12 and 0⩽pT2⩽3 (GeV/c)2 (for positive beam) and −0.12⩽xF⩽0.4 and 0⩽pT2⩽10 (GeV/c)2 (for negative beam). We find substantial asymmetries, even at xF around zero. We also observe leading-particle-type asymmetries. These latter effects are qualitatively as expected from valence-quark content of the target and variety of projectiles studied

First measurements of inclusive W and Z cross sections from Run II of the Fermilab Tevatron collider

We report the first measurements of inclusive W and Z cross sections times leptonic branching ratios for pp¯ collisions at s√=1.96  TeV, based on their decays to electrons and muons. The data correspond to an integrated luminosity of 72  pb−1 recorded with the CDF detector at the Fermilab Tevatron. We test e-μ universality in W decays, and we measure the ratio of leptonic W and Z rates from which the leptonic branching fraction B(W→ℓν) can be extracted as well as an indirect value for the total width of the W and the Cabibbo-Kobayashi-Maskawa matrix element V c