2,622 research outputs found
An acoustic wind measuring technique.
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76876/1/AIAA-1966-440-561.pd
Time Series Evidence of Relationships Between U.S. and Canadian Wheat Prices
U.S. wheat producers contend that Canadian production subsidies and implicit export subsidies have undermined the U.S. price support program. The authors examine this contention and assess the relationships between U.S. and Canadian wheat prices using a cointegration and error approach. The results suggest that both U.S. durum and hard spring wheat prices respond to restore the equilibrium relationship with the corresponding Canadian price while the Canadian price does not respond to restore equilibria
Estimation of Demand for Wheat by Classes for the United States and the European Union
In North America and Europe, wheat is a very important commodity that has been at the heart of trade disputes and policy conflicts. This study uses a dynamic Almost Ideal Demand System (AIDS) to estimate demand elasticities for wheat differentiated by classes, for the United States and the European Union (EU). The results suggest that in the U.S. market imported wheat is more price responsive than domestic wheat. In the EU, however, price responsiveness varies according to the quality of wheat rather than its national origin
Short-term fate of rehabilitated orphan black bears released in New Hampshire
We evaluated the release of rehabilitated, orphan black bears (Ursus americanus) in northern New Hampshire. Eleven bears (9 males, 2 females; 40–45 kg) were outfitted with GPS radio-collars and released during May and June of 2011 and 2012. Bears released in 2011 had higher apparent survival and were not observed or reported in any nuisance behavior, whereas no bears released in 2012 survived, and all were involved in minor nuisance behavior. Analysis of GPS locations indicated that bears in 2011 had access to and used abundant natural forages or habitat. Conversely, abundance of soft and hard mast was lower in 2012, suggesting that nuisance behavior, and consequently survival, was inversely related to availability of natural forage. Dispersal from the release site ranged from 3.4–73 km across both years, and no bear returned to the rehabilitation facility (117 km distance). Rehabilitation appears to be a valid method for addressing certain orphan bear issues in New Hampshire
Design considerations for a Space Station radiation shield for protection from both man-made and natural sources
This study was conducted to analyze scenarios involving the use of nuclear-power vehicles in the vicinity of a manned Space Station (SS) in low-earth-orbit (LEO) to quantify their radiological impact to the station crew. In limiting the radiant dose to crew members, mission planners may (1) shut the reactor down prior to reentry, (2) position the vehicle at a prescribed parking distance, and (3) deploy radiation shield about the shutdown reactor. The current report focuses on the third option in which point-kernel gamma-ray shielding calculations were performed for a variety of shield configurations for both nuclear electric propulsion (NEP) and nuclear thermal rocket (NTR) vehicles. For a returning NTR vehicle, calculations indicate that a 14.9 MT shield would be needed to limit the integrated crew exposure to no more than 0.05 Sv over a period of six months (25 percent of the allowable exposure to man-made radiation sources). During periods of low vehicular activity in LEO, the shield may be redeployed about the SS habitation module in order to decrease crew exposures to trapped proton radiations by approximately a factor of 10. The corresponding shield mass required for deployment at a returning NEP vehicle is 2.21 MT. Additional scenarios examined include the radioactivation of various metals as might be found in tools used in EVA activities
Law of One Price in International Commodity Markets: A Fractional Cointegration Analysis
The Law of One Price (LOP) is an important component of most, if not all, international trade models because this assumption allows researchers to use a single representative price for all regions. This paper examines the long-run LOP for international commodity prices using a generalized notion of cointegration called fractional cointegration. This analysis is applied to nine pairs of price series, supporting the existence of LOP in eight cases
Col-OSSOS: Colors of the Interstellar Planetesimal 1I/`Oumuamua
The recent discovery by Pan-STARRS1 of 1I/2017 U1 (`Oumuamua), on an unbound
and hyperbolic orbit, offers a rare opportunity to explore the planetary
formation processes of other stars, and the effect of the interstellar
environment on a planetesimal surface. 1I/`Oumuamua's close encounter with the
inner Solar System in 2017 October was a unique chance to make observations
matching those used to characterize the small-body populations of our own Solar
System. We present near-simultaneous g, r, and J photometry
and colors of 1I/`Oumuamua from the 8.1-m Frederick C. Gillett Gemini North
Telescope, and photometry from the 4.2 m William Herschel Telescope. Our
grJ observations are directly comparable to those from the
high-precision Colours of the Outer Solar System Origins Survey (Col-OSSOS),
which offer unique diagnostic information for distinguishing between outer
Solar System surfaces. The J-band data also provide the highest signal-to-noise
measurements made of 1I/`Oumuamua in the near-infrared. Substantial, correlated
near-infrared and optical variability is present, with the same trend in both
near-infrared and optical. Our observations are consistent with 1I/`Oumuamua
rotating with a double-peaked period of hours and being a
highly elongated body with an axial ratio of at least 5.3:1, implying that it
has significant internal cohesion. The color of the first interstellar
planetesimal is at the neutral end of the range of Solar System and
solar-reflectance colors: it is like that of some dynamically excited objects
in the Kuiper belt and the less-red Jupiter Trojans.Comment: Accepted to ApJ
Hearing and whistling in the deep sea: Depth influences whistle spectra but does not attenuate hearing by white whales (Delphinapterus leucas) (Odontoceti, Cetacea)
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