2,223 research outputs found
The economic impacts of climate change: Evidence from agricultural output and random fluctuations in weather: Comment
In a series of studies employing a variety of approaches, we have found that the potential impact of climate change on US agriculture is likely negative. Deschênes and Greenstone (2007) report dramatically different results based on regressions of agricultural profits and yields on weather variables. The divergence is explained by (1) missing and incorrect weather and climate data in their study; (2) their use of older climate change projections rather than the more recent and less optimistic projections from the Fourth Assessment Report; and (3) difficulties in their profit measure due to the confounding effects of storage
Letters from Wm. Chas. Roberts, J. B. Fisher, A. H. Throckmorton, Lucien Waggener, J. W. Logan, and A. B. Nelson
Letters of recommendation for O. W. Long
A preliminary audit of medical and aid provision in English Rugby union clubs:compliance with Regulation 9
BackgroundGoverning bodies are largely responsible for the monitoring and management of risks associated with a safe playing environment, yet adherence to regulations is currently unknown. The aim of this study was to investigate and evaluate the current status of medical personnel, facilities, and equipment in Rugby Union clubs at regional level in England.MethodsA nationwide cross-sectional survey of 242 registered clubs was undertaken, where clubs were surveyed online on their current medical personnel, facilities, and equipment provision, according to regulation 9 of the Rugby Football Union (RFU).ResultsOverall, 91 (45. 04%) surveys were returned from the successfully contacted recipients. Of the completed responses, only 23.61% (n = 17) were found to be compliant with regulations. Furthermore, 30.56% (n = 22) of clubs were unsure if their medical personnel had required qualifications; thus, compliance could not be determined. There was a significant correlation (p = −0.029, r = 0.295) between club level and numbers of practitioners. There was no significant correlation indicated between the number of practitioners/number of teams and number of practitioners/number of players. There were significant correlations found between club level and equipment score (p = 0.003, r = −0.410), club level and automated external defibrillator (AED) access (p = 0.002, r = −0.352) and practitioner level and AED access (p = 0.0001, r = 0.404). Follow-up, thematic analysis highlighted widespread club concern around funding/cost, awareness, availability of practitioners and AED training.ConclusionThe proportion of clubs not adhering overall compliance with Regulation 9 of the RFU is concerning for player welfare, and an overhaul, nationally, is required
Body odor quality predicts behavioral attractiveness in humans
Growing effort is being made to understand how different attractive physical traits co-vary within individuals, partly because this might indicate an underlying index of genetic quality. In humans, attention has focused on potential markers of quality such as facial attractiveness, axillary odor quality, the second-to-fourth digit (2D:4D) ratio and body mass index (BMI). Here we extend this approach to include visually-assessed kinesic cues (nonverbal behavior linked to movement) which are statistically independent of structural physical traits. The utility of such kinesic cues in mate assessment is controversial, particularly during everyday conversational contexts, as they could be unreliable and susceptible to deception. However, we show here that the attractiveness of nonverbal behavior, in 20 male participants, is predicted by perceived quality of their axillary body odor. This finding indicates covariation between two desirable traits in different sensory modalities. Depending on two different rating contexts (either a simple attractiveness rating or a rating for long-term partners by 10 female raters not using hormonal contraception), we also found significant relationships between perceived attractiveness of nonverbal behavior and BMI, and between axillary odor ratings and 2D:4D ratio. Axillary odor pleasantness was the single attribute that consistently predicted attractiveness of nonverbal behavior. Our results demonstrate that nonverbal kinesic cues could reliably reveal mate quality, at least in males, and could corroborate and contribute to mate assessment based on other physical traits
Theory of Parabolic Arcs in Interstellar Scintillation Spectra
Our theory relates the secondary spectrum, the 2D power spectrum of the radio
dynamic spectrum, to the scattered pulsar image in a thin scattering screen
geometry. Recently discovered parabolic arcs in secondary spectra are generic
features for media that scatter radiation at angles much larger than the rms
scattering angle. Each point in the secondary spectrum maps particular values
of differential arrival-time delay and fringe rate (or differential Doppler
frequency) between pairs of components in the scattered image. Arcs correspond
to a parabolic relation between these quantities through their common
dependence on the angle of arrival of scattered components. Arcs appear even
without consideration of the dispersive nature of the plasma. Arcs are more
prominent in media with negligible inner scale and with shallow wavenumber
spectra, such as the Kolmogorov spectrum, and when the scattered image is
elongated along the velocity direction. The arc phenomenon can be used,
therefore, to constrain the inner scale and the anisotropy of scattering
irregularities for directions to nearby pulsars. Arcs are truncated by finite
source size and thus provide sub micro arc sec resolution for probing emission
regions in pulsars and compact active galactic nuclei. Multiple arcs sometimes
seen signify two or more discrete scattering screens along the propagation
path, and small arclets oriented oppositely to the main arc persisting for long
durations indicate the occurrence of long-term multiple images from the
scattering screen.Comment: 22 pages, 11 figures, submitted to the Astrophysical Journa
Atmospheric emissions from the deepwater Horizon spill constrain air-water partitioning, hydrocarbon fate, and leak rate
The fate of deepwater releases of gas and oil mixtures is initially determined by solubility and volatility of individual hydrocarbon species; these attributes determine partitioning between air and water. Quantifying this partitioning is necessary to constrain simulations of gas and oil transport, to predict marine bioavailability of different fractions of the gas-oil mixture, and to develop a comprehensive picture of the fate of leaked hydrocarbons in the marine environment. Analysis of airborne atmospheric data shows massive amounts (∼258,000 kg/day) of hydrocarbons evaporating promptly from the Deepwater Horizon spill; these data collected during two research flights constrain air-water partitioning, thus bioavailability and fate, of the leaked fluid. This analysis quantifies the fraction of surfacing hydrocarbons that dissolves in the water column (∼33% by mass), the fraction that does not dissolve, and the fraction that evaporates promptly after surfacing (∼14% by mass). We do not quantify the leaked fraction lacking a surface expression; therefore, calculation of atmospheric mass fluxes provides a lower limit to the total hydrocarbon leak rate of 32,600 to 47,700 barrels of fluid per day, depending on reservoir fluid composition information. This study demonstrates a new approach for rapid-response airborne assessment of future oil spills. Copyright 2011 by the American Geophysical Union
The Ultraviolet Imaging Telescope: Instrument and Data Characteristics
The Ultraviolet Imaging Telescope (UIT) was flown as part of the Astro
observatory on the Space Shuttle Columbia in December 1990 and again on the
Space Shuttle Endeavor in March 1995. Ultraviolet (1200-3300 Angstroms) images
of a variety of astronomical objects, with a 40 arcmin field of view and a
resolution of about 3 arcsec, were recorded on photographic film. The data
recorded during the first flight are available to the astronomical community
through the National Space Science Data Center (NSSDC); the data recorded
during the second flight will soon be available as well. This paper discusses
in detail the design, operation, data reduction, and calibration of UIT,
providing the user of the data with information for understanding and using the
data. It also provides guidelines for analyzing other astronomical imagery made
with image intensifiers and photographic film.Comment: 44 pages, LaTeX, AAS preprint style and EPSF macros, accepted by PAS
Current quark mass dependence of nucleon magnetic moments and radii
A calculation of the current-quark-mass-dependence of nucleon static
electromagnetic properties is necessary in order to use observational data as a
means to place constraints on the variation of Nature's fundamental parameters.
A Poincare' covariant Faddeev equation, which describes baryons as composites
of confined-quarks and -nonpointlike-diquarks, is used to calculate this
dependence The results indicate that, like observables dependent on the
nucleons' magnetic moments, quantities sensitive to their magnetic and charge
radii, such as the energy levels and transition frequencies in Hydrogen and
Deuterium, might also provide a tool with which to place limits on the allowed
variation in Nature's constants.Comment: 23 pages, 2 figures, 4 tables, 4 appendice
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