126 research outputs found
Exceptional skull of huayqueriana (mammalia, litopterna, macraucheniidae) from the late miocene of Argentina: Anatomy, systematics, and peleobiological implications
The Huayquerías Formation (Late Miocene, Huayquerian SALMA) is broadly exposed in westcentral Argentina (Mendoza). The target of several major paleontological expeditions in the first half of the 20th century, the Mendozan Huayquerías (badlands) have recently yielded a significant number of new fossil finds. In this contribution we describe a complete skull (IANIGLA-PV 29) and place it systematically as Huayqueriana cf. H. cristata (Rovereto, 1914) (Litopterna, Macraucheniidae). The specimen shares some nonexclusive features with H. cristata (similar size, rostral border of the orbit almost level with distal border of M3, convergence of maxillary bones at the level of the P3/P4 embrasure, flat snout, very protruding orbits, round outline of premaxillary area in palatal view, and small diastemata between I3/C and C/P1). Other differences (e.g., lack of sagittal crest) may or may not represent intraspecific variation. In addition to other features described here, endocast reconstruction utilizing computer tomography (CT) revealed the presence of a derived position of the orbitotemporal canal running below the rhinal fissure along the lateroventral aspect of the piriform lobe. CT scanning also established that the maxillary nerve (CN V2) leaves the skull through the sphenoorbital fissure, as in all other litopterns, a point previously contested for macraucheniids. The angle between the lateral semicircular canal and the plane of the base of the skull is about 26°, indicating that in life the head was oriented much as in modern horses. Depending on the variables used, estimates of the body mass of IANIGLA-PV 29 produced somewhat conflicting results. Our preferred body mass estimate is 250 kg, based on the centroid size of 36 3D cranial landmarks and accompanying low prediction error. The advanced degree of tooth wear in IANIGLA-PV 29 implies that the individual died well into old age. However, a count of cementum lines on the sectioned left M2 is consistent with an age at death of 10 or 11 years, younger than expected given its body mass. This suggests that the animal had a very abrasive diet. Phylogenetic analysis failed to resolve the position of IANIGLA-PV 29 satisfactorily, a result possibly influenced by intraspecific variation. There is no decisive evidence for the proposition that Huayqueriana, or any other litoptern, were foregut fermenters.Fil: Forasiepi, Analia Marta. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: MacPhee, Ross D. E.. American Museum Of Natural History; Estados UnidosFil: Hernández del Pino, Santiago Ezequiel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Schmidt, Gabriela Ines. Provincia de Entre Ríos. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción. Universidad Autónoma de Entre Ríos. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción; ArgentinaFil: Amson, Eli. Universitat Zurich; SuizaFil: Grohé, Camille. American Museum Of Natural History; Estados Unido
Search for jet extinction in the inclusive jet-pT spectrum from proton-proton collisions at s=8 TeV
Published by the American Physical Society under the terms of the Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published articles title, journal citation, and DOI.The first search at the LHC for the extinction of QCD jet production is presented, using data collected with the CMS detector corresponding to an integrated luminosity of 10.7 fb−1 of proton-proton collisions at a center-of-mass energy of 8 TeV. The extinction model studied in this analysis is motivated by the search for signatures of strong gravity at the TeV scale (terascale gravity) and assumes the existence of string couplings in the strong-coupling limit. In this limit, the string model predicts the suppression of all high-transverse-momentum standard model processes, including jet production, beyond a certain energy scale. To test this prediction, the measured transverse-momentum spectrum is compared to the theoretical prediction of the standard model. No significant deficit of events is found at high transverse momentum. A 95% confidence level lower limit of 3.3 TeV is set on the extinction mass scale
Searches for electroweak neutralino and chargino production in channels with Higgs, Z, and W bosons in pp collisions at 8 TeV
Searches for supersymmetry (SUSY) are presented based on the electroweak pair production of neutralinos and charginos, leading to decay channels with Higgs, Z, and W bosons and undetected lightest SUSY particles (LSPs). The data sample corresponds to an integrated luminosity of about 19.5 fb(-1) of proton-proton collisions at a center-of-mass energy of 8 TeV collected in 2012 with the CMS detector at the LHC. The main emphasis is neutralino pair production in which each neutralino decays either to a Higgs boson (h) and an LSP or to a Z boson and an LSP, leading to hh, hZ, and ZZ states with missing transverse energy (E-T(miss)). A second aspect is chargino-neutralino pair production, leading to hW states with E-T(miss). The decays of a Higgs boson to a bottom-quark pair, to a photon pair, and to final states with leptons are considered in conjunction with hadronic and leptonic decay modes of the Z and W bosons. No evidence is found for supersymmetric particles, and 95% confidence level upper limits are evaluated for the respective pair production cross sections and for neutralino and chargino mass values
Home range overlap, matrilineal and biparental kinship drive female associations in bottlenose dolphins
Few studies of kinship in mammalian societies have been able to consider the complex interactions between home range overlap, association patterns and kinship, which have created a critical gap in our understanding of social evolution. We investigated the association patterns of female bottlenose dolphins, Tursiops aduncus, in the eastern gulf of Shark Bay, Western Australia and found that they depended upon the complex interplay of at least three factors: home range overlap, matrilineal kinship and biparental kinship. While home range overlap was positively correlated with female association patterns, preferred associations were found between females showing as little as 27% home range overlap, and some pairs showed avoidance despite 100% home range overlap. Furthermore, on average, both casual and preferred associations took place between females that were more closely biparentally related than expected by chance and this pattern varied depending upon whether or not pairs of females shared the same matriline
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