28,538 research outputs found

    The milliped genus Euryurus Koch, 1847 (Polydesmida: Euryuridae) west of the Mississippi River; occurrence of E. leachii (Gray, 1832) on Crowley’s Ridge, Arkansas

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    The milliped genus Euryurus Koch, 1847, and the species, E. leachii (Gray, 1832) (Polydesmida: Euryuridae), are recorded from three sites on the northern part of Crowley’s Ridge (Cross, Lee, and Poinsett counties), Arkansas, where the only prior familial records are of Auturus evides (Bollman, 1887). Coupled with the published locality of E. leachii in Phillips Co., at the southern extremity of the Ridge, the only known occurrences of both the genus and species in Arkansas and west of the Mississippi River are in this physiographic feature. The Arkansas population is geographically peripheral but anatomically intermediate between the two recognized subspecies, E. l. leachii and E. l. fraternus Hoffman, 1978, and we do not assign it to a race. Molecular investigations seem necessary to resolve relationships in the “E. leachii complex.

    Measuring and Testing Advertising-Induced Rotation in the Demand Curve

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    Advertising can rotate the demand curve if it changes the dispersion of consumers valuations. We provide an elasticity form measure of the advertising-induced demand curve rotation in five demand models and test for its presence in the U.S. non-alcoholic beverage market. The AIDS model reveals that doubling advertising spending rotates the demand curves clockwise for milk, and coffee and tea with associated slope changes of 7.3% and 11.6%. Soft-drink advertising rotates its demand curve counterclockwise. Our policy suggestion is that milk and soft-drink firms might enhance profits by timing advertising to coincide with high- and low-price periods, respectively.Demand and Price Analysis,

    ADVERTISING, STRUCTURAL CHANGE, AND U.S. NON-ALCOHOLIC BEVERAGE DEMAND

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    The dominant trend in U.S. non-alcoholic consumption over the past two decades has been a steady increase in soft-drink consumption, largely at the expense of milk and coffee and tea consumption. Our analysis suggests that the primary factors affecting this is that the price, advertising, and demographic elasticities estimated from the Rotterdam model are much smaller than the adjusted trend coefficients and the expenditure elasticities.Consumer/Household Economics, Demand and Price Analysis, Marketing,

    Flight tests of a direct lift control system during approach and landing

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    Flight tests of modified aileron direct lift control system during approach and landing of F8-C aircraf

    Bond breaking with auxiliary-field quantum Monte Carlo

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    Bond stretching mimics different levels of electron correlation and provides a challenging testbed for approximate many-body computational methods. Using the recently developed phaseless auxiliary-field quantum Monte Carlo (AF QMC) method, we examine bond stretching in the well-studied molecules BH and N2_2, and in the H50_{50} chain. To control the sign/phase problem, the phaseless AF QMC method constrains the paths in the auxiliary-field path integrals with an approximate phase condition that depends on a trial wave function. With single Slater determinants from unrestricted Hartree-Fock (UHF) as trial wave function, the phaseless AF QMC method generally gives better overall accuracy and a more uniform behavior than the coupled cluster CCSD(T) method in mapping the potential-energy curve. In both BH and N2_2, we also study the use of multiple-determinant trial wave functions from multi-configuration self-consistent-field (MCSCF) calculations. The increase in computational cost versus the gain in statistical and systematic accuracy are examined. With such trial wave functions, excellent results are obtained across the entire region between equilibrium and the dissociation limit.Comment: 8 pages, 3 figures and 3 tables. Submitted to JC

    The minimum free-stream wind speed for initiating motion of surface material on Mars

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    Estimates of the minimum free-stream wind speed that is required for initiating the motion of surficial material on Mars have ranged from 30 to about 200 meters per second. Thus the best value for this quantity is not well established. Graphical comparison of much of the pertinent data taken in the laboratory and in the field on Earth provides a minimum value for the Bagnold coefficient of 0.08 and this in turn provides a minimum value for the threshold friction velocity of 1.3 meters per second for initiating motion of particulate matter on Mars at low elevations where the pressure is 7 millibars. The most appropriate value of the ratio of friction velocity to free-stream velocity for putative unstable condition appears to be 0.026. Thus the minimum free-stream wind speed for initiating motion is obtained as 50 meters per second. If the surface material on Mars, however, is less cohesive than that on earth, the minimum value may be smaller
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