5,982 research outputs found

    A Dirac Sea and thermodynamic equilibrium for the quantized three-wave interaction

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    The classical version of the three wave interaction models the creation and destruction of waves; the quantized version models the creation and destruction of particles. The quantum three wave interaction is described and the Bethe Ansatz for the eigenfunctions is given in closed form. The Bethe equations are derived in a rigorous fashion and are shown to have a thermodynamic limit. The Dirac sea of negative energy states is obtained as the infinite density limit. Finite particle/hole excitations are determined and the asymptotic relation of energy and momentum is obtained. The Yang-Yang functional for the relative free energy of finite density excitations is constructed and is shown to be convex and bounded below. The equations of thermal equilibrium are obtained

    A Risk Analysis of Converting CRP Acres to a Wheat-Sorghum-Fallow Rotation

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    This study examines the economic potential of producing a wheat (Triticum aesitivum) and grain sorghum (Sorghum bicolor (L.) Moench) rotation with three different tillage strategies compared to the Conservation Reserve Program (CRP) in a semi-arid region. This research uses stochastic efficiency with respect to a function (SERF) to determine the preferred management strategies under various risk preferences and utility-weighted certainty equivalent risk premiums. Yields, input rates, and field operations from an experimental field in western Kansas are used to calculate net returns for each tillage strategy. Although current net returns to crop production using reduced tillage and no-tillage strategies are higher than CRP, risk analysis indicates CRP would be the preferred strategy for some risk-averse managers.Conservation Reserve Program, conservation tillage, simulation, sorghum, wheat, risk, Agricultural and Food Policy, Crop Production/Industries, Farm Management, Land Economics/Use, Risk and Uncertainty,

    Net Returns for Grain Sorghum and Corn under Alternative Irrigation Systems in Western Kansas

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    This study evaluates seven irrigation systems for use in production of grain sorghum and corn. These systems are medium pressure center-pivot (MPCP), low pressure center-pivot (LPCP), low drift nozzle center-pivot (LDN) , low energy precision application center-pivot (LEPA), furrow flood (FF) , surge flood (SF), and subsurface drip (SD). After-tax net present value estimates from investing in and using each system over a 10-year period to produce grain sorghum and corn are compared. The surge flood system, has the highest net returns under typical conditions for irrigation of both grain sorghum and corn. The furrow flood system generates the next highest net returns for both crops, followed by the subsurface drip system. The medium pressure center-pivot system is the least profitable for both crops. Of the center-pivot systems, the low pressure system has the highest net return, but is followed very closely by the low drift nozzle system. The results of the sensitivity analysis indicate that the net return estimates and ranking of the subsurface drip system are very sensitive to the yield response to irrigation. Lower than average crop prices also have a substantial impact on the ranking of this system. The original investment cost is also an important determinant of its net return.Crop Production/Industries,

    Detection of cannabinoids in hair after cosmetic application of hemp oil.

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    The detection of cannabis constituents and metabolites in hair is an established procedure to provide evidence of exposure to cannabis. We present the frst known evidence to suggest that applying hemp oil to hair, as cosmetic treatment, may result in the incorporation of Δ9-tetrahydrocannabinol (THC), cannabinol (CBN), cannabidiol (CBD) and in one instance, the metabolite 11-hydroxy-Δ9- tetrahydrocannabinol (THC-OH). 10 volunteers treated their head hair daily with commercially available hemp oil for a period of 6 weeks. Head hair samples were collected before and after the application period. Hair samples were washed with methanol and subjected to clean up via liquid/ liquid and solid phase extraction procedures, and then GC-MS/MS for the analysis of THC, CBN, CBD, THC-OH and THC-COOH. Application of hemp oil to hair resulted in the incorporation of one or more cannabis constituents in 89% of volunteers, and 33% of the group tested positive for the three major constituents, THC, CBN and CBD. One volunteer showed low levels of the metabolite THC-OH. We suggest that cosmetic use of hemp oil should be recorded when sampling head hair for analysis, and that the interpretative value of cannabinoid hair measurements from people reporting application of hemp oil is treated with caution in both criminology and public health

    Integrated stratigraphy of the Kimmeridge Clay Formation (Upper Jurassic) based on exposures and boreholes in south Dorset, UK

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    For the purposes of a high-resolution multi-disciplinary study of the Upper Jurassic Kimmeridge Clay Formation, two boreholes were drilled at Swanworth Quarry and one at Metherhills, south Dorset, UK. Together, the cores represent the first complete section through the entire formation close to the type section. We present graphic logs that record the stratigraphy of the cores, and outline the complementary geophysical and analytical data sets (gamma ray, magnetic susceptibility, total organic carbon, carbonate, [delta]13Corg). Of particular note are the new borehole data from the lowermost part of the formation which does not crop out in the type area. Detailed logs are available for download from the Kimmeridge Drilling Project web-site at http://kimmeridge.earth.ox.ac.uk/. Of further interest is a mid-eudoxus Zone positive shift in the [delta]13Corg record, a feature that is also registered in Tethyan carbonate successions, suggesting that it is a regional event and may therefore be useful for correlation. The lithostratigraphy of the cores has been precisely correlated with the nearby cliff section, which has also been examined and re-described. Magnetic-susceptibility and spectral gamma-ray measurements were made at a regular spacing through the succession, and facilitate core-to-exposure correlation. The strata of the exposure and core have been subdivided into four main mudrock lithological types: (a) medium-dark–dark-grey marl; (b) medium-dark–dark grey–greenish black shale; (c) dark-grey–olive-black laminated shale; (d) greyish-black–brownish-black mudstone. The sections also contain subordinate amounts of siltstone, limestone and dolostone. Comparison of the type section with the cores reveals slight lithological variation and notable thickness differences between the coeval strata. The proximity of the boreholes and different parts of the type section to the Purbeck–Isle of Wight Disturbance is proposed as a likely control on the thickness changes

    Sensory and repetitive behaviors among children with autism spectrum disorder at home

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    Atypical sensory and repetitive behaviors are defining features of autism spectrum disorder (ASD) and are thought to be influenced by environmental factors; however, there is a lack of naturalistic research exploring contexts surrounding these behaviors. The current study involved video recording observations of 32 children with ASD (2 – 12 years of age) engaging in sensory and repetitive behaviors during home activities. Behavioral coding was used to determine what activity contexts, sensory modalities, and stimulus characteristics were associated with specific behavior types: hyperresponsive, hyporesponsive, sensory seeking, and repetitive/stereotypic. Results indicated that hyperresponsive behaviors were most associated with activities of daily living and family-initiated stimuli, whereas sensory seeking behaviors were associated with free play activities and child-initiated stimuli. Behaviors associated with multiple sensory modalities simultaneously were common, emphasizing the multi-sensory nature of children’s behaviors in natural contexts. Implications for future research more explicitly considering context are discussed

    A risk analysis of adjusted gross revenue-lite on beef farms

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    This study evaluates the Adjusted Gross Revenue-Lite (AGR-Lite) whole-farm adjusted gross revenue insurance program on net farm income risk using panel data from 49 southeast Kansas beef farms. On average for the group, but not each individual farm, AGR-Lite reduces the mean and standard deviation of net farm income, raises the average minimum, and lowers the average maximum observations of the net income distribution. Thirty-four farms (69%) received at least one indemnity payment. Stochastic efficiency with respect to a function reveals that AGR-Lite is preferred by 18 of the farm managers (37%) when an upper bound on the risk-aversion coefficient is used

    Radiatively driven hypersonic wind tunnel

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76604/1/AIAA-12568-479.pd

    Laboratory and Clinical Studies of Cardiac Transplantation

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    Cardiac transplantation was carried out on four patients at the Medical College of Virginia between May and October of 1968, in an effort to salvage them from the terminal stages of otherwise uncorrectable heart disease. Despite a strikingly good early recovery from operation in each case, three of the patients died of acute homograft rejection in one to three weeks; our second case is living and well, ten months after operation, and is at this writing the world\u27s third longest survivor. The world experience to June of 1969 includes about 130 cardiac transplants. Of the first 100 patients operated on over six months ago, 20 are surviving, and the majority of these have returned to a productive existence, demonstrating the feasibility of complete rehabilitation of at least some terminal patients after cardiac transplantation. The high mortality rate--significantly higher than was anticipated--has resulted from acute and chronic homograft rejection and from the equally difficult problem of infection. Certain lessons have been learned from our own experience and from the world experience with this procedure, and these will be reviewed in an attempt to establish the current status and future potential of cardiac transplantation
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