Hyphessobrycon natagaima (Characiformes: Characidae) a new species from Colombia, with a key to the Magdalena Basin Hyphessobrycon species

A new species, Hyphessobrycon natagaima, is described from the upper Magdalena River Basin in Colombia. It differs from all other species of Hyphessobrycon with a dark lateral stripe inhabiting the Magdalena River Basin: H. poecilioides, H. proteus and H. ocasoensis, by having eight to twelve pored lateral-line scales (vs. 14-26); four scales between the lateral line and the pelvic-fin insertions (vs. five or six); one tooth on the maxilla (vs. zero in H. poecilioides, and two to five in H. proteus; except H. ocasoensis, with one), a dark, interrupted, lateral stripe that is not in contact with the caudal peduncle spot (vs. absence of caudal spot in H. poecilioides, lateral stripe continued that is in contact with the caudal peduncle spot in H. ocasoensis). It has a rhomboid shaped caudal-peduncle spot that continues on to middle caudal-fin rays (vs. absence of caudal peduncle spot in H. poecilioides and caudal peduncle spot round and not continued on to middle caudal-fin rays in H. ocasoensis); and presence of hooks on all fins in mature males (vs. males with hooks on anal, pelvic and pectoral fins). Hyphessobrycon natagaima differs from H. ocasoensis, in addition to the above characters, by having four scale rows between the lateral line and the anal-fin origin (vs. six); three or four scale rows between the lateral line and the pelvic-fin insertions (vs. six); ten or eleven predorsal scales (vs. nine); i,9,i dorsal-fin rays (vs. ii,8,i); 18-20 branched anal-fin rays (vs. 21-22) and eleven branched pectoral-fin rays (vs. twelve). A key for the identification of Hyphessobrycon species present in the Magdalena River Basin is provided

First record of the miniature catfish Malacoglanis gelatinosus Myers & Weitzman, 1966 (Siluriformes, Trichomycteridae) in the Orinoco river basin

Malacoglanis gelatinosus, a species of miniature catfish of the family Trichomycteridae, is only known from 4 specimens from the Amazon basin. Recently, we collected 3 specimens from the upper basin of the Meta River, a tributary of the Orinoco. This is the first record of M. gelatinosus from the Orinoco river basin, which significantly expands the known geographic distribution of this species, making it one of the most broadly distributed species within the subfamily Sarcoglanidinae. High-resolution photographs of specimens, remarks on character variation, and an updated distribution in Colombia are provided

First records of the family Scoloplacidae (Siluriformes, Loricarioidei) in Colombia, including a range expansion of Scoloplax baileyi Rocha, Lazzarotto & Py-Daniel, 2012

The Neotropical family Scoloplacidae is a monogeneric group of miniature freshwater catfishes that includes 6 species. Scoloplax dicra has the widest distribution across the Amazon basin, except in the western upper portions. We collected 3 specimens from localities close to Leticia in Colombia, corresponding to S. baileyi and S. dicra, constituting the westernmost records of the family for the Amazon basin and the first for Colombia

Caracterización biológica de Paz de Ariporo. Identificación de especies claves para establecer límites de humedales.

Se exponen los resultados y evaluaciones en campo de la ventana piloto de humedales de Paz de Ariporo- Hato Corozal en el marco del convenio 005 (13-014) entre el Instituto Humboldt y el Fondo Adaptación.BogotáSubdirección de Servicios Científicos y Proyectos Especiale

Standalone vertex finding in the ATLAS muon spectrometer

A dedicated reconstruction algorithm to find decay vertices in the ATLAS muon spectrometer is presented. The algorithm searches the region just upstream of or inside the muon spectrometer volume for multi-particle vertices that originate from the decay of particles with long decay paths. The performance of the algorithm is evaluated using both a sample of simulated Higgs boson events, in which the Higgs boson decays to long-lived neutral particles that in turn decay to bbar b final states, and pp collision data at √s = 7 TeV collected with the ATLAS detector at the LHC during 2011

Measurements of Higgs boson production and couplings in diboson final states with the ATLAS detector at the LHC

Measurements are presented of production properties and couplings of the recently discovered Higgs boson using the decays into boson pairs, H →γ γ, H → Z Z∗ →4l and H →W W∗ →lνlν. The results are based on the complete pp collision data sample recorded by the ATLAS experiment at the CERN Large Hadron Collider at centre-of-mass energies of √s = 7 TeV and √s = 8 TeV, corresponding to an integrated luminosity of about 25 fb−1. Evidence for Higgs boson production through vector-boson fusion is reported. Results of combined fits probing Higgs boson couplings to fermions and bosons, as well as anomalous contributions to loop-induced production and decay modes, are presented. All measurements are consistent with expectations for the Standard Model Higgs boson

Measurement of the top quark-pair production cross section with ATLAS in pp collisions at \sqrt{s}=7\TeV

A measurement of the production cross-section for top quark pairs(\ttbar) in $pp$ collisions at \sqrt{s}=7 \TeV is presented using data recorded with the ATLAS detector at the Large Hadron Collider. Events are selected in two different topologies: single lepton (electron $e$ or muon $\mu$) with large missing transverse energy and at least four jets, and dilepton ($ee$, $\mu\mu$ or $e\mu$) with large missing transverse energy and at least two jets. In a data sample of 2.9 pb-1, 37 candidate events are observed in the single-lepton topology and 9 events in the dilepton topology. The corresponding expected backgrounds from non-\ttbar Standard Model processes are estimated using data-driven methods and determined to be $12.2 \pm 3.9$ events and $2.5 \pm 0.6$ events, respectively. The kinematic properties of the selected events are consistent with SM \ttbar production. The inclusive top quark pair production cross-section is measured to be \sigmattbar=145 \pm 31 ^{+42}_{-27} pb where the first uncertainty is statistical and the second systematic. The measurement agrees with perturbative QCD calculations.Comment: 30 pages plus author list (50 pages total), 9 figures, 11 tables, CERN-PH number and final journal adde

Measurement of the top quark pair cross section with ATLAS in pp collisions at √s=7 TeV using final states with an electron or a muon and a hadronically decaying τ lepton

A measurement of the cross section of top quark pair production in proton-proton collisions recorded with the ATLAS detector at the Large Hadron Collider at a centre-of-mass energy of 7 TeV is reported. The data sample used corresponds to an integrated luminosity of 2.05 fb -1. Events with an isolated electron or muon and a τ lepton decaying hadronically are used. In addition, a large missing transverse momentum and two or more energetic jets are required. At least one of the jets must be identified as originating from a b quark. The measured cross section, σtt-=186±13(stat.)±20(syst.)±7(lumi.) pb, is in good agreement with the Standard Model prediction

Hunt for new phenomena using large jet multiplicities and missing transverse momentum with ATLAS in 4.7 fb−1 of √s=7 TeV proton-proton collisions

Results are presented of a search for new particles decaying to large numbers of jets in association with missing transverse momentum, using 4.7 fb−1 of pp collision data at s√=7TeV collected by the ATLAS experiment at the Large Hadron Collider in 2011. The event selection requires missing transverse momentum, no isolated electrons or muons, and from ≥6 to ≥9 jets. No evidence is found for physics beyond the Standard Model. The results are interpreted in the context of a MSUGRA/CMSSM supersymmetric model, where, for large universal scalar mass m 0, gluino masses smaller than 840 GeV are excluded at the 95% confidence level, extending previously published limits. Within a simplified model containing only a gluino octet and a neutralino, gluino masses smaller than 870 GeV are similarly excluded for neutralino masses below 100 GeV