6,275 research outputs found
Special geometry of Euclidean supersymmetry IV:the local c-map
We consider timelike and spacelike reductions of 4D, N = 2 Minkowskian and Euclidean vector multiplets coupled to supergravity and the maps induced on the scalar geometry. In particular, we investigate (i) the (standard) spatial c-map, (ii) the temporal c-map, which corresponds to the reduction of the Minkowskian theory over time, and (iii) the Euclidean c-map, which corresponds to the reduction of the Euclidean theory over space. In the last two cases we prove that the target manifold is para-quaternionic Kahler. In cases (i) and (ii) we construct two integrable complex structures on the target manifold, one of which belongs to the quaternionic and para-quaternionic structure, respectively. In case (iii) we construct two integrable para-complex structures, one of which belongs to the para-quaternionic structure. In addition we provide a new global construction of the spatial, temporal and Euclidean c-maps, and separately consider a description of the target manifold as a fibre bundle over a projective special Kahler or para-Kahler base
Kinematics of a globular cluster with an extended profile: NGC5694
We present a study of the kinematics of the remote globular cluster NGC5694
based on GIRAFFE@VLT medium resolution spectra. A sample of 165 individual
stars selected to lie on the Red Giant Branch in the cluster Color Magnitude
Diagram was considered. Using radial velocity and metallicity from Calcium
triplet, we were able to select 83 bona-fide cluster members. The addition of
six previously known members leads to a total sample of 89 cluster giants with
typical uncertainties <1.0 km/s in their radial velocity estimates. The sample
covers a wide range of projected distances from the cluster center, from ~0.2
arcmin to 6.5 arcmin = 23 half-light radii (r_h). We find only very weak
rotation, as typical of metal-poor globular clusters. The velocity dispersion
gently declines from a central value of sigma=6.1 km/s to sigma = 2.5 km/s at
~2 arcmin = 7.1= r_h, then it remainins flat out to the next (and last)
measured point of the dispersion profile, at ~4 arcmin = 14.0 r_h, at odds with
the predictions of isotropic King models. We show that both isotropic
single-mass non-collisional models and multi-mass anisotropic models can
reproduce the observed surface brightness and velocity dispersion profiles.Comment: Accepted for publication by MNRAS. Pdflatex, 10 pages, 10 figure
Contribution to the knowledge of bovine besnoitiosis in Portugal
Bovine besnoitiosis is a parasitic disease caused by the protozoa Besnoitia besnoiti (Marotel, 1912) that presents an acute phase (with fever and anasarca) and a chronic phase (with sclerodermitis), and has been characterized by high morbidity and low mortality (Ferreira, 1985). A study on the presence of besnoitiosis was carried out in October 2001 on a beef cattle herd located in the Évora region. On this farm, where previous cases of besnoitiosis were diagnosed, 12 assymptomatic Limousine bulls, aged between 18 and 24 months, were randomly selected and studied. Skin biopsies were collected and prepared. Subsequent histopathologic analyses of the biopsies have shown that 5 (42%) of the animals studied harboured B. besnoiti cysts. Therefore, these results demonstrate the immediate need to obtain insight in to some as yet not clearly defined aspects of the physiopathogeny of this disease. Possible ways of transmission (that is, determination of intermediate as well as definite hosts) and their impact on animal production such as bovine fertility and the quality of skins for leather industry should be addressed. In addition, the cases of assymptomatic animals with B. besnoiti in the Évora district should be clarified
Interferometric Mapping of Magnetic fields: NGC2071IR
We present polarization maps of NGC2071IR from thermal dust emission at 1.3
mm and from CO J= line emission. The observations were obtained using
the Berkeley-Illinois-Maryland Association array in the period 2002-2004. We
detected dust and line polarized emission from NGC2071IR that we used to
constrain the morphology of the magnetic field. From CO J= polarized
emission we found evidence for a magnetic field in the powerful bipolar outflow
present in this region. We calculated a visual extinction mag from our dust observations. This result, when compared with early
single dish work, seems to show that dust grains emit polarized radiation
efficiently at higher densities than previously thought. Mechanical alignment
by the outflow is proposed to explain the polarization pattern observed in
NGC2071IR, which is consistent with the observed flattening in this source.Comment: 17 pages, 4 Figures, Accepted for publication in Ap
The CARMENES search for exoplanets around M dwarfs - Photospheric parameters of target stars from high-resolution spectroscopy
The new CARMENES instrument comprises two high-resolution and high-stability
spectrographs that are used to search for habitable planets around M dwarfs in
the visible and near-infrared regime via the Doppler technique. Characterising
our target sample is important for constraining the physical properties of any
planetary systems that are detected. The aim of this paper is to determine the
fundamental stellar parameters of the CARMENES M-dwarf target sample from
high-resolution spectra observed with CARMENES. We also include several M-dwarf
spectra observed with other high-resolution spectrographs, that is CAFE, FEROS,
and HRS, for completeness. We used a {chi}^2 method to derive the stellar
parameters effective temperature T_eff, surface gravity log g, and metallicity
[Fe/H] of the target stars by fitting the most recent version of the
PHOENIX-ACES models to high-resolution spectroscopic data. These stellar
atmosphere models incorporate a new equation of state to describe spectral
features of low-temperature stellar atmospheres. Since T_eff, log g, and [Fe/H]
show degeneracies, the surface gravity is determined independently using
stellar evolutionary models. We derive the stellar parameters for a total of
300 stars. The fits achieve very good agreement between the PHOENIX models and
observed spectra. We estimate that our method provides parameters with
uncertainties of {sigma} T_eff = 51 K, {sigma} log g = 0.07, and {sigma} [Fe/H]
= 0.16, and show that atmosphere models for low-mass stars have significantly
improved in the last years. Our work also provides an independent test of the
new PHOENIX-ACES models, and a comparison for other methods using
low-resolution spectra. In particular, our effective temperatures agree well
with literature values, while metallicities determined with our method exhibit
a larger spread when compared to literature results
Pseudoclassical theories of Majorana, Weyl and Majorana--Weyl particles
A pseudoclassical theories of Majorana, Weyl and Majorana--Weyl particles in
the space--time dimensions are constructed. The canonical quantization
of these theories is carried out and as a result we obtain the quantum
mechanical description of neutral particle in , Weyl particle in
and neutral Weyl particle in . In dimensional
space--time the description of the neutral particle coincides with the field
theoretical description of the Majorana particle in the Foldy--Wouthuysen
representation. In dimensions the neutral Weyl particle coincides with
the Majorana--Weyl particle in the Foldy--Wouthuysen representation.Comment: LATEX, 17 pages, no figure
Efeito do filtrado de Epicoccum sp. na formação de apressórios por Magnaporthe oryzae.
O objetivo deste trabalho foi avaliar a ação do filtrado de Epicoccum sp., integrante da microflora do arroz, na inibição da germinação de conídios e na formação de apressórios de M. oryzae
A study of randomness, correlations and collectivity in the nuclear shell model
A variable combination of realistic and random two-body interactions allows
the study of collective properties, such as the energy spectra and B(E2)
transition strengths in 44Ti, 48Cr and 24Mg. It is found that the average
energies of the yrast band states maintain the ordering for any degree of
randomness, but the B(E2) values lose their quadrupole collectivity when
randomness dominates the Hamiltonian. The high probability of the yrast band to
be ordered in the presence of pure random forces exhibits the strong
correlations between the different members of the band.Comment: 8 pages, 10 figures, 8 tables, submitted to Physical Review
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