2,937 research outputs found
Variação temporal e espacial de fluxo evasivo de CO2 e exportação de carbono orgânico dissolvido em pequenas bacias de drenagem na Amazônia Oriental.
Poster 254. Disponível também on-lie
Ab-initio study of model guanine assemblies: The role of pi-pi coupling and band transport
Several assemblies of guanine molecules are investigated by means of
first-principle calculations. Such structures include stacked and
hydrogen-bonded dimers, as well as vertical columns and planar ribbons,
respectively, obtained by periodically replicating the dimers. Our results are
in good agreement with experimental data for isolated molecules, isolated
dimers, and periodic ribbons. For stacked dimers and columns, the stability is
affected by the relative charge distribution of the pi orbitals in adjacent
guanine molecules. pi-pi coupling in some stacked columns induces dispersive
energy bands, while no dispersion is identified in the planar ribbons along the
connections of hydrogen bonds. The implications for different materials
comprised of guanine aggregates are discussed. The bandstructure of dispersive
configurations may justify a contribution of band transport (Bloch type) in the
conduction mechanism of deoxyguanosine fibres, while in DNA-like configurations
band transport should be negligible.Comment: 21 pages, 6 figures, 3 tables, to be published in Phys. Rev.
Cultural Orientations of sport managers
Various interpretations of sport management are cultural constructs underpinned by core assumptions and values held by members of professional communities. Sport managers world wide share common problems, but differ in how they resolve them. These universal differences emerge from the relationships they form with other people, and their attitude to time, activities and the natural environment. This paper examines the role of sport managers’ cultural orientations in the interpretation and practice of sport management. Using a multiple dimension model (Hampden-Turner and Trompenaars, 2000) it sketches the cultural profiles of fifteen sport managers from seven countries. A combination of methods was employed including questionnaires, interviews and participant observation. It is contended that the culture of sport management concerns a social process by which managers get involved in reconciling seven fundamental cultural dilemmas in order to perform tasks and achieve certain ends. Thus, a knowledge of the cultural meaning of sport management in a particular country would equip sport managers with a valuable tool in managing both the cultural diversity of their own work forces and in developing appropriate cross-cultural skills needed for running international events, marketing campaigns, sponsorship deals and joint ventures
Planck Intermediate Results. IX. Detection of the Galactic haze with Planck
Using precise full-sky observations from Planck, and applying several methods
of component separation, we identify and characterize the emission from the
Galactic "haze" at microwave wavelengths. The haze is a distinct component of
diffuse Galactic emission, roughly centered on the Galactic centre, and extends
to |b| ~35 deg in Galactic latitude and |l| ~15 deg in longitude. By combining
the Planck data with observations from the WMAP we are able to determine the
spectrum of this emission to high accuracy, unhindered by the large systematic
biases present in previous analyses. The derived spectrum is consistent with
power-law emission with a spectral index of -2.55 +/- 0.05, thus excluding
free-free emission as the source and instead favouring hard-spectrum
synchrotron radiation from an electron population with a spectrum (number
density per energy) dN/dE ~ E^-2.1. At Galactic latitudes |b|<30 deg, the
microwave haze morphology is consistent with that of the Fermi gamma-ray "haze"
or "bubbles," indicating that we have a multi-wavelength view of a distinct
component of our Galaxy. Given both the very hard spectrum and the extended
nature of the emission, it is highly unlikely that the haze electrons result
from supernova shocks in the Galactic disk. Instead, a new mechanism for
cosmic-ray acceleration in the centre of our Galaxy is implied.Comment: 15 pages, 9 figures, submitted to Astronomy and Astrophysic
Measurement of the atmospheric muon depth intensity relation with the NEMO Phase-2 tower
The results of the analysis of the data collected with the NEMO Phase-2
tower, deployed at 3500 m depth about 80 km off-shore Capo Passero (Italy), are
presented. Cherenkov photons detected with the photomultipliers tubes were used
to reconstruct the tracks of atmospheric muons. Their zenith-angle distribution
was measured and the results compared with Monte Carlo simulations. An
evaluation of the systematic effects due to uncertainties on environmental and
detector parameters is also included. The associated depth intensity relation
was evaluated and compared with previous measurements and theoretical
predictions. With the present analysis, the muon depth intensity relation has
been measured up to 13 km of water equivalent.Comment: submitted to Astroparticle Physic
- …