35 research outputs found
A new key locality for the Pliocene vertebrate record of Europe : the Camp dels Ninots maar (NE Spain)
A new Pliocene Konservat-LagerstÀtte in north-eastern Spain is described here for the first time. It is referred to as Camp dels Ninots. The particular geological conditions of the site, which correspond to lacustrine sedimentation in a maar, made it ideal for the preservation of fossils. At present, five large mammal skeletons in anatomical connection have been recovered: three individuals of Alephis tigneresi, one of Stephanorhinus jeanvireti and one of Tapirus arvernenis, as well as isolated remains. A minimum of five individuals of the chelonian Mauremys leprosa have been recovered, some of them in anatomical connection. The rodent Apodemus atavus, the amphibians cf. Pleurodeles sp., Lissotriton aff. helveticus and Pelophylax cf. perezi and freshwater fishes (Leuciscus ?) complete the vertebrate assemblage uncovered up to the present time. The coexistence of Stephanorhinus jeanvireti and Alephis tigneresi suggests an age of about 3.2Ma for the Camp dels Ninots, near the MN15-MN16 transition. The Camp del Ninots fossil record enables one to extend the biogeographic range of some vertebrate taxa, such as Stephanorhinus jeanvireti, Tapirus arvernensis or Mauremys leprosa to the Iberian Peninsula. Taphonomic evidences of the skeletal remains indicates minimal (if any) weathering. Deposition at the lake bottom seems to have taken place in oxygen depleted layers. In this way, Camp dels Ninots is comparable to other remarkable maar sites such as Messel, the Eocene site situated in Germany
Leaky doors: private captivity as a prominent source of bird introductions in Australia
The international pet trade is a major source of emerging invasive vertebrate species. We used online resources as a novel source of information for accidental bird escapes, and we investigated the factors that influence the frequency and distribution of bird escapes at a continental scale. We collected information on over 5,000 pet birds reported to be missing on animal websites during the last 15 years in Australia. We investigated whether variables linked to pet ownership successfully predicted bird escapes, and we assessed the potential distribution of these escapes. Most of the reported birds were parrots (> 90%), thus, we analysed factors associated with the frequency of parrot escapes. We found that bird escapes in Australia are much more frequent than previously acknowledged. Bird escapes were reported more frequently within, or around, large Australian capital cities. Socio-economic factors, such as the average personal income level of the community, and the level of human modification to the environment were the best predictors of bird escapes. Cheaper parrot species, Australian natives, and parrot species regarded as peaceful or playful were the most frequently reported escapees. Accidental introductions have been overlooked as an important source of animal incursions. Information on bird escapes is available online in many higher income countries and, in Australia, this is particularly apparent for parrot species. We believe that online resources may provide useful tools for passive surveillance for non-native pet species. Online surveillance will be particularly relevant for species that are highly reported, such as parrots, and species that are either valuable or highly commensal.Miquel Vall-llosera, Phillip Casse
Photoelectron and threshold photoelectron valence spectra of pyridine
The pyridine molecule has been examined by the means of photoelectron and threshold photoelectron spectroscopies. Ionization energies were determined for both outer and inner valence orbitals and new adiabatic values were also resolved. Vibronic structure associated with several states was assigned mainly to be due to C-C stretches and ring bends. Additionally a Rydberg state converging to 7b2 state was ascribed. The data shown here are in a good agreement with previous results and brings some new insights into the electronic structure of this biologically and astrochemically relevant and important molecule
COCONUT requirements for residential, business and outdoor scenarios
Five basic requirements have been defined for the COCONUT ultra-dense WDM PON architecture: (1) untouched optical distribution network, (2) no active components, (3) no intervention in the outside plan, (4) smooth upgrade from legacy systems, and (5) use of the same technology for point-to-point and point-to-multi-point links. These requirements are analysed with respect to five application scenarios: main remote, small cell backhaul/residential, business, and macro cell backhaul. The low-cost coherent techniques targeted in the project will allow for increased power budget, thus splitting ratio, distance, and a narrower grid that will enable a densification of the network as foreseen with small cell deployments
The C 1s and N 1s near edge x-ray absorption fine structure spectra of five azabenzenes in the gas phase
12 pags., 4 figs., 8 tabs., 1 app.Near edge x-ray absorption fine structure spectra have been measured and interpreted by means of density functional theory for five different azabenzenes (pyridine, pyridazine, pyrimidine, pyrazine, and s -triazine) in the gas phase. The experimental and theoretical spectra at the N 1s and C 1s edges show a strong resonance assigned to the transition of the 1s electron in the respective N or C atoms to the lowest unoccupied molecular orbital with Ï* symmetry. As opposed to the N 1s edge, at the C 1s edge this resonance is split due to the different environments of the core hole atom in the molecule. The shift in atomic core-level energy due to a specific chemical environment is explained with the higher electronegativity of the N atom compared to the C atom. The remaining resonances below the ionization potential (IP) are assigned to transitions to valence/Rydberg orbitals with mixed Ï* character. Upon N addition, a reduction of intensity is observed in the Rydberg region at both edges as compared to the intensity in the continuum. Above the IP one or more resonances are seen and ascribed here to transitions to * orbitals. Calculating the experimental and theoretical ÎÏ term values at both edges, we observe that they are almost the same within ±1 eV as expected for isoelectronic bonded pairs. The term values of the Ï* and * resonances are discussed in terms of the total Z number of the atoms participating in the bond. © 2008 American Institute of Physics.The authors acknowledge support provided by the European Community-Research Infrastructure Action under the
FP6 âStructuring the European Research Areaâ Programme through the Integrated Infrastructure Initiative âIntegrating
Activity on Synchrotron and Free Electron Laser Scienceâ
and from the Swedish Science Research Council, VR