2,909 research outputs found
Rice and Water: The Final Frontier
Outlines the threat of diminishing water resources for rice crops, the economic and social dimensions of the droughts' potential effects, and the new cultural systems and adapted rice varieties being pursued as potential solutions
Spatial Variations of Fundamental Constants
We show that observational limits on the possible time variation of constants
of Nature are significantly affected by allowing for both space and time
variation. Bekenstein's generalisation of Maxwell's equations to allow for
cosmological variation of is investigated in a universe containing
spherically symmetric inhomogeneities. The time variation of is
determined by the local matter density and hence limits obtained in
high-density geophysical enviroments are far more constraining than those
obtained at high redshift. This new feature is expected to be a property of a
wide class of theories for the variation of constants.Comment: 4 page
The role of financing frictions in agricultural investment decisions: an analysis pre and post financial crisis
This paper uses a fundamental Q model of investment to consider the role played by financing frictions in agricultural investment decisions, controlling econometrically for censoring, heterogeneity and errors-in-variables. Our findings suggest that farmer's investment decisions are not driven by market fundamentals. We find some evidence that debt overhang restricts investment but investment is not dependent on liquidity or internal funds. The role of financing frictions in determining investment decisions changes in the post-financial crisis period when debt overhang becomes a significant impediment to farm investment. The evidence suggests that farmers increasingly rely on internal liquidity to drive investment. Finally, we find no evidence that farmers use on-farm capital to fund on-farm investment.Credit Constraints, Firm Level Investment, Tobin's Q, Debt, Agricultural Finance, G31, G32, F34,
The subdwarf B star SB 290 - A fast rotator on the extreme horizontal branch
Hot subdwarf B stars (sdBs) are evolved core helium-burning stars with very
thin hydrogen envelopes. In order to form an sdB, the progenitor has to lose
almost all of its hydrogen envelope right at the tip of the red giant branch.
In close binary systems, mass transfer to the companion provides the
extraordinary mass loss required for their formation. However, apparently
single sdBs exist as well and their formation is unclear since decades. The
merger of helium white dwarfs leading to an ignition of core helium-burning or
the merger of a helium core and a low mass star during the common envelope
phase have been proposed. Here we report the discovery of SB 290 as the first
apparently single fast rotating sdB star located on the extreme horizontal
branch indicating that those stars may form from mergers.Comment: 5 pages, 4 figures, A&A letters, accepte
The Rockefeller Foundation's International Program on Rice Biotechnology
Presents the product of a two-year intensive survey and analysis of the genetic prospects for the world's major food crops conducted in the early 1980s
The MultiSite Spectroscopic Telescope campaign: 2m spectroscopy of the V361 Hya variable PG1605+072
We present results and analysis for the 2m spectroscopic part of the
MultiSite Spectroscopic Telescope (MSST) campaign undertaken in May/June 2002.
The goal of the project was to observe the pulsating subdwarf B star PG1605+072
simultaneously in velocity and photometry and to resolve as many of the >50
known modes as possible, which will allow a detailed asteroseismological
analysis. We have obtained over 150 hours of spectroscopy, leading to an
unprecedented noise level of only 207m/s. We report here the detection of 20
frequencies in velocity, with two more likely just below our detection
threshold. In particular, we detect 6 linear combinations, making PG1605+072
only the second star known to show such frequencies in velocity. We investigate
the phases of these combinations and their parent modes and find relationships
between them that cannot be easily understood based on current theory. These
observations, when combined with our simultaneous photometry, should allow
asteroseismology of this most complicated of sdB pulsators.Comment: 9 pages, 5 figures, accepted for publication in A&A; Figure 1 at
lower resolution than accepted versio
An all-Ireland epidemiological study of MND, 2004-2005
Background and methods: We conducted an all-Ireland population-based prospective epidemiological survey of motor neurone disease (MND) using the Northern Ireland and Republic of Ireland MND registers to examine the incidence and prevalence of the disease over the period 2004–2005.Results and conclusions: Incidence of MND was 1.9 per 100 000 person-years and rates were comparable in both the north and south of Ireland. Prevalence of MND was 5.0 per 100 000 population. When compared with previous published surveys of MND performed in the Republic of Ireland over the last 10 years, rates of disease have remained relatively constant. When standardized to the 1990 US population, the incidence of MND in Ireland was found to be consistent with other European prospective surveys of MND
Multi-wavelength photometric variation of PG1605+072
In a large coordinated attempt to further our understanding of the -mode
pulsating sdB star PG1605+072, the Multi-Site Spectroscopic Telescope (MSST)
collaboration has obtained simultaneous time-resolved spectroscopic and
photometric observations. The photometry was extended by additional WET data
which increased the time base. This contribution outlines the analysis of the
MSST photometric light curve, including the four-colour BUSCA data from which
chromatic amplitudes have been derived, as well as supplementary FUV spectra
and light curves from two different epochs. These results have the potential to
complement the interpretation of the published spectroscopic information.Comment: 6 pages, to be published in "Interpretation of asteroseismic data",
proceedings of the HELAS NA5 Workshop, eds. W. Dziembowski, M. Breger and M.
Thompson, Communications in Asteroseismology, 15
Radial velocity variations of the pulsating subdwarf B star PG 1605+072
We present an analysis of high-speed spectroscopy of the pulsating subdwarf B
star PG 1605+072. Periodic radial motions are detected at frequencies similar
to those reported for photometric variations in the star, with amplitudes of up
to 6 km/s. Differences between relative strengths for given frequency peaks for
our velocity data and previously measured photometry are probably a result of
shifting of power between modes over time. Small differences in the detected
frequencies may also indicate mode-shifting. We report the detection of
line-shape variations using the moments of the cross correlation function
profiles. It may be possible to use the moments to identify the star's
pulsation modes.Comment: 5 pages, 6 figure
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