5,672 research outputs found
Improving the Tanzanian-Mombasa cross-border tomato product chain: a study of Mombasa tomato market : draft report
The study of Mombasa tomato market is part of the project “Development of Commercial Field Vegetable Production, Distribution and Marketing for the East African Market”. The project is implementing a pilot activity on improving crossborder tomato chains from Ngarenanyuki, Tanzania, to Mombasa, Kenya. The overall objective of the study was to assess the requirements, institutional setting and current supply issues of the Mombasa tomato market and to describe the supply chain logistics and characteristics
Radio Monitoring of the January 11, 1997 Gamma-Ray Burst
We report on a comprehensive radio monitoring program of the bright gamma-ray
burster GRB970111. These VLA observations were made at a frequency of 1.4 GHz
and span a range of post-burst timescales between 28 hours and one month.
Despite extensive sampling at sub-milliJansky sensitivities, no radio source
was detected above 0.5 mJy in the current best error box (~14 arcmin^2) for
GRB970111. A highly unusual radio source, VLA J1528.7+1945, was seen to drop in
flux density by a factor of two in our monitoring period but it lies outside
the error box and thus it is unlikely to be related to GRB970111. Cosmological
fireball models of gamma-ray bursts make predictions of late-time emission
occurring at longer wavelengths. The absence of a flaring or fading radio
counterpart to GRB970111 provides strong constraints on these models.Comment: ApJ Let (accepted
The yellow hypergiants HR 8752 and rho Cassiopeiae near the evolutionary border of instability
High-resolution near-ultraviolet spectra of the yellow hypergiants HR 8752
and rho Cassiopeiae indicate high effective temperatures placing both stars
near the T_eff border of the ``yellow evolutionary void''. At present, the
temperature of HR 8752 is higher than ever. For this star we found
Teff=7900+-200 K, whereas rho Cassiopeiae has Teff=7300+-200 K. Both, HR 8752
and rho Cassiopeiae have developed strong stellar winds with Vinf ~ 120 km/s
and Vinf ~ 100 km/s, respectively. For HR 8752 we estimate an upper limit for
the spherically symmetric mass-loss of 6.7X10^{-6}M_solar/yr. Over the past
decades two yellow hypergiants appear to have approached an evolutionary phase,
which has never been observed before. We present the first spectroscopic
evidence of the blueward motion of a cool super/hypergiant on the HR diagram.Comment: 13 pages including 3 figures. Accepted for publication in ApJ Letter
Elliptic Flow and Fixed p_T Suppression in a Final State Interaction Model
It has been shown that a final state interaction model, used to describe
J/psi suppression, can also describe the fixed p_T suppression of the pi^0 (and
charged pions) yield at all values of p_T, with a final state interaction
cross-section sigma close to one milibarn. We propose an extension of the model
to the pion motion in the transverse plane - which introduces a dependence of
the suppression on the azimuthal angle theta_R. Using the same value of sigma,
we obtain values of the elliptic flow v_2 close to the experimental ones, for
all values of p_T, including the soft p_T region.Comment: 21 pages, 6 figure
Effects of Home Value, Home Age, and Lot Size on Lawn Watering Practices of Residential Homeowners
Lawn care and lawn watering practices of residential homeowners were significantly affected by home value and home age, but lot size was less a factor
Crossing the `Yellow Void' -- Spatially Resolved Spectroscopy of the Post- Red Supergiant IRC+10420 and Its Circumstellar Ejecta
IRC +10420 is one of the extreme hypergiant stars that define the empirical
upper luminosity boundary in the HR diagram. During their post--RSG evolution,
these massive stars enter a temperature range (6000-9000 K) of increased
dynamical instability, high mass loss, and increasing opacity, a
semi--forbidden region, that de Jager and his collaborators have called the
`yellow void'. We report HST/STIS spatially resolved spectroscopy of IRC +10420
and its reflection nebula with some surprising results. Long slit spectroscopy
of the reflected spectrum allows us to effectively view the star from different
directions. Measurements of the double--peaked Halpha emission profile show a
uniform outflow of gas in a nearly spherical distribution, contrary to previous
models with an equatorial disk or bipolar outflow. Based on the temperature and
mass loss rate estimates that are usually quoted for this object, the wind is
optically thick to the continuum at some and possibly all wavelengths.
Consequently the observed variations in apparent spectral type and inferred
temperature are changes in the wind and do not necessarily mean that the
underlying stellar radius and interior structure are evolving on such a short
timescale. To explain the evidence for simultaneous outflow and infall of
material near the star, we propose a `rain' model in which blobs of gas
condense in regions of lowered opacity outside the dense wind. With the
apparent warming of its wind, the recent appearance of strong emission, and a
decline in the mass loss rate, IRC +10420 may be about to shed its opaque wind,
cross the `yellow void', and emerge as a hotter star.Comment: To appear in the Astronomical Journal, August 200
Wind Turbine Generator System Safety and Function Test Report for the Ventera VT10 Wind Turbine
This report summarizes the results of a safety and function test that NREL conducted on the Ventera VT10 wind turbine. This test was conducted in accordance with the International Electrotechnical Commissions' (IEC) standard, Wind Turbine Generator System Part 2: Design requirements for small wind turbines, IEC 61400-2 Ed.2.0, 2006-03
Vector Boson Pair Production via Vector Boson Fusion at NLO QCD
NLO QCD corrections to Vector Boson Pair Production via Vector Boson Fusion
have recently been calculated and implemented in a parton-level Monte-Carlo
program with full experimental cuts. We briefly sketch the elements of the
calculation and show numerical results for the Large Hadron Collider.Comment: 6 pages, 3 figures, presented by G.Bozzi at IFAE 2007 (Napoli, April
2007) and HEP 2007 (Manchester, July 2007
Duration Test Report for the Entegrity EW50 Wind Turbine
This report summarizes the results of a duration test that NREL conducted on the Entegrity EW50 wind turbine. This test was conducted in accordance with the International Electrotechnical Commissions' (IEC) standard, Wind Turbine Generator System Part 2: Design requirements for small wind turbines, IEC 61400-2 Ed.2.0, 2006-03
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