99 research outputs found
Contribution à l'étude du système de phosphotransfert de carbohydrates dépendant du phosphoénolpyruvate {PTS) chez B. melitensis 16M
Sistem Informasi Strategis Mendayagunakan Sistem Informasi untuk Mencapai Keunggulan Kompetitif
While most companies are content to develop and implement computer-based information systems to improve their operational and managerial effectiveness, a few also rely on innovative systems to give them an edge over the competition. An information system that is specifically designed with the aim to create a competitive advantage for its firm is called a strategic information system.To build a strategic information system, one should have a good understanding as to what factors contribute towards competitive advantage. It is here that the analyses by Michael E. Porter on this subject are particularly invaluable. Furthermore, one should also realize what the modern computer excels at fast processing time, fast data retrieval, fast communications, and reliability.There are also risks inherent to strategic information systems. These include the large capital outlay involved, as well as the reality that any competitive advantage thus achieved is not sustainable for long
Probing the stellar populations of early-type galaxies: the SAURON survey
The SAURON project will deliver two-dimensional spectroscopic data of a
sample of nearby early-type galaxies with unprecedented quality. In this paper,
we focus on the mapping of their stellar populations using the SAURON data, and
present some preliminary results on a few prototypical cases.Comment: 12 pages, 6 figures. ASP Conference, Galaxies: the Third Dimension,
Cozumel. Version with higher resolution figures available at
http://www-obs.univ-lyon1.fr/eric.emsellem/papers/cozumel_emsellem.ps.g
Functional Characterization of the Incomplete Phosphotransferase System (PTS) of the Intracellular Pathogen Brucella melitensis
Background: In many bacteria, the phosphotransferase system (PTS) is a key player in the regulation of the assimilation of alternative carbon sources notably through catabolic repression. The intracellular pathogens Brucella spp. possess four PTS proteins (EI Ntr, NPr, EIIA Ntr and an EIIA of the mannose family) but no PTS permease suggesting that this PTS might serve only regulatory functions
Evidence of environmental dependencies of Type la supernovae from the Nearby Supernova Factory indicated by local H alpha (Corrigendum)
Two-dimensional kinematics and stellar populations of early-type galaxies: First results from the SAURON survey
We present the SAURON project, which is aimed at studying the morphology,
two-dimensional kinematics and stellar populations of a representative sample
of elliptical galaxies and spiral bulges. SAURON, a dedicated integral-field
spectrograph that is optimized for wide-field observations and has high
throughput, was built in Lyon and is now operated at the WHT 4.2m telescope. At
present, we have observed approximately two thirds of the seventy-two sample
galaxies with SAURON. A comparison with published long-slit measurements
demonstrates that the SAURON-data is of equal or better quality, and provides
full two-dimensional coverage. The velocity and velocity dispersion fields
exhibit a large variety of morphologies: from simple rotating systems to
cylindrical, disky and triaxial velocity fields, bars and decoupled cores. Most
of these kinematical signatures do not have counterparts in the light
distribution. While some galaxies are consistent with axisymmetry, most are
more complex systems than assumed previously. This suggests that the
kinematical properties of nearby E/S0 galaxies do not agree with the often
assumed simplistic two-family model, in which the giant non-rotating triaxial
ellipticals are opposed to the fast-rotating axisymmetric faint ellipticals and
S0s.Comment: 10 pages, 6 figures, conference "galaxies: the third dimension",
cozumel, mexico, 3-7 december 200
Visible and Near-Infrared Spectrophotometry of the Deep Impact Ejecta of Comet 9P/Tempel 1
We have obtained optical spectrophotometry of the evolution of comet
9P/Tempel 1 after the impact of the Deep Impact probe, using the Supernova
Integral Field Spectrograph (SNIFS) at the UH 2.2m telescope, as well as
simultaneous optical and infrared spectra using the Lick
Visible-to-Near-Infrared Imaging Spectrograph (VNIRIS) spectrograph. The
spatial distribution and temporal evolution of the "violet band" CN (0-0)
emission and of the 630 nm [OI] emission was studied. We found that CN emission
centered on the nucleus increased in the two hours after impact, but that this
CN emission was delayed compared to the light curve of dust-scattered sunlight.
The CN emission also expanded faster than the cloud of scattering dust. The
emission of [OI] at 630 nm rose similarly to the scattered light, but then
remained nearly constant for several hours after impact. On the day following
the impact, both CN and [OI] emission concentrated on the comet nucleus had
returned nearly to pre-impact levels. We have also searched for differences in
the scattering properties of the dust ejected by the impact compared to the
dust released under normal conditions. Compared to the pre-impact state of the
comet, we find evidence that the color of the comet was slightly bluer during
the post-impact rise in brightness. Long after the impact, in the following
nights, the comet colors returned to their pre-impact values. This can be
explained by postulating a change to a smaller particle size distribution in
the ejecta cloud, in agreement with the findings from mid-infrared observatons,
or by postulating a large fraction of clean ice particles, or by a combination
of these two.Comment: 28 pages of text and 8 figures. Paper is accepted for publication in
Icaru
Determination of masses of the central black holes in NGC524 and NGC2549 using Laser Guide Star Adaptive Optics
[abridged] We present observations of NGC524 and NGC2549 with LGS AO obtained
at GEMINI North telescope using the NIFS IFU in the K band. The purpose of
these observations, together with previously obtained observations with the
SAURON IFU, is to determine the masses (Mbh) of the supermassive black holes
(SMBH). The targeted galaxies were chosen to have central light profiles
showing a core (NGC524) and a cusp (NGC2549), to probe the feasibility of using
the galaxy centre as the NGS required for LGS AO. We employ an innovative `open
loop' technique. The data have spatial resolution of 0.23" and 0.17" FWHM,
showing that high quality LGS AO observations of these objects are possible. We
construct axisymmetric three-integral dynamical models which are constrained
with both the NIFS and SAURON data. The best fitting models yield Mbh=(8.3 +2.7
-1.3) x 10^8 Msun for NGC524 and Mbh=(1.4 +0.2 -1.3) x 10^7 Msun for NGC2549
(all errors are at the 3 sigma CL). We demonstrate that the wide-field SAURON
data play a crucial role in the M/L determination increasing the accuracy of
M/L by a factor of at least 5, and constraining the upper limits on Mbh. The
NIFS data are crucial in constraining the lower limits of Mbh and in
combination with the large scale data reducing the uncertainty by a factor of 2
or more. We find that the orbital structure of NGC524 shows significant
tangential anisotropy, while at larger radii both galaxies are consistent with
having almost perfectly oblate velocity ellipsoids. Tangential anisotropy in
NGC524 coincides with the size of SMBH sphere of influence and the core region
in the light profile. We test the accuracy to which Mbh can be measured using
seeings obtained from typical LGS AO observations, and conclude that for a
typical conditions and Mbh the expected uncertainty is of the order of 50%.Comment: 19 pages, 14 figure
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