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C. J. Adcock 《Annals of Operations Research》2010,176(1):221-234
The returns on most financial assets exhibit kurtosis and many also have probability distributions that possess skewness as
well. In this paper a general multivariate model for the probability distribution of assets returns, which incorporates both
kurtosis and skewness, is described. It is based on the multivariate extended skew-Student-t distribution. Salient features of the distribution are described and these are applied to the task of asset pricing. The
paper shows that the market model is non-linear in general and that the sensitivity of asset returns to return on the market
portfolio is not the same as the conventional beta, although this measure does arise in special cases. It is shown that the
variance of asset returns is time varying and depends on the squared deviation of market portfolio return from its location
parameter. The first order conditions for portfolio selection are described. Expected utility maximisers will select portfolios
from an efficient surface, which is an analogue of the familiar mean-variance frontier, and which may be implemented using
quadratic programming. 相似文献
14.
A sequential injection analysis procedure with dual-reagent chemiluminescence detection was applied to the screening of street drug seizure samples for the presence of heroin. The chemiluminescence reagents (acidic potassium permanganate and tris(2,2'-bipyridine)ruthenium(III)) were aspirated from either side of a sample aliquot that was sufficiently large to prevent interdispersion of the reagent zones, and therefore two different chemical reactions could be performed simultaneously at either end of the sample zone. The presence of heroin in seizure samples was indicated by a strong response with the tris(2,2'-bipyridine)ruthenium(III) reagent and confirmed by a significant increase in the response with the permanganate reagent when the sample was treated with sodium hydroxide to hydrolyse the heroin to morphine. Nicomorphine (a morphine-derived pharmaceutical) was synthesised and tested under the same conditions. The responses with the permanganate reagent were similar to those for heroin, which supports the proposed chemical basis for the test. However, the responses with tris(2,2'-bipyridine)ruthenium(III) were far lower for nicomorphine than heroin (approximately 5-fold for the samples that had not been hydrolysed). 相似文献
15.
A critical and comprehensive review of acidic potassium permanganate chemiluminescence is presented. This includes discussion on reaction conditions, the influence of enhancers such as polyphosphates, formaldehyde and sulfite, the relationship between analyte structure and chemiluminescence intensity, and the application of this chemistry to determine a wide variety of compounds, such as pharmaceuticals, biomolecules, antioxidants, illicit drugs, pesticides and pollutants. Previous proposals for the nature of the emitting species are re-evaluated in light of recent evidence. 相似文献
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A number of Cr(CO)3 complexes of bridgehead-substituted phenylbicyclo[2.2.2]octanes and (m- and p-)fluoropheylbicyclo[2.2.2]octanes have been synthesized and their 13C and 19F NMR spectra have been recorded, respectively. The substituent chemical shifts (SCS) of these stereochemically well-defined model systems permit an unambiguous evaluation of polar factors governing 13C and 19F SCS in arene-Cr(CO)3 complexes. The dual nature of 19F NMR polar field effects is reaffirmed and the coefficient (A) of the Buckingham equation for linear electric field effects on C(sp2)F bonds in fluoroarene-Cr(CO)3 complexes has been calculated. A re-examination and re-interpretation of the 19F chemical shifts of m- and p-substituted fluorophenyltricarbonylchromium derivatives is also reported. New substituent parameters (σI and σoR) for C6H5 · Cr(CO)3 as a substituent in the neutral ground state arepresented. 相似文献
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A method was developed for the quantitation of pentoxifylline [1-(5-oxohexyl)-3,7-dimethylxanthine] and a primary active metabolite, lisofylline [1-(5-hydroxyhexyl)-3,7-dimethylxanthine], using high-performance liquid chromatography (HPLC)-tandem mass spectrometry. This method was developed in order to overcome problems encountered with HPLC-ultraviolet detection. The operating parameters of the electrospray interface (PE SCIEX, TurboIon Spray) and lens voltages of the triple-quadrupole detector (PE SCIEX 365) were optimized in positive ion mode to obtain the best sensitivity of the analytes. Collision-induced dissociation was used to produce fragment ions, and multiple reaction monitoring was used to quantitate pentoxifylline (m/z 279/181) and lisofylline (m/z 263/181). Dichloromethane was used to extract the drug, metabolite, and the internal standard (3-isobutyl-1-methylxanthine) from plasma. A reverse-phase C8(2) 150 x 1.0 mm HPLC column was used to resolve all three compounds in less than 6 min. Calibration curves were generated using peak area and were linear from 1 to 1000 ng/mL (R(2) > 0.99). The small sample volume, ease of extraction, and sensitivity provide advantages over more conventional methods of quantitation. 相似文献
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Hodge H. Phillips James F. Kinstle James L. Adcock 《Journal of polymer science. Part A, Polymer chemistry》1981,19(1):175-194
Uncrosslinked atactic polystyrene was chemically modified first by acetylation then by a Claisen condensation with ethyl perfluoropropanoate to produce three crosslinked chelating polymers that contained a phenyl, perfluoroethyl, beta-diketone chelating group in 10, 20, and 63 mole % compositions. Cu(II), Ni(II), and uranyl chelates of the macromolecular ligands were prepared and analyzed. The macromolecular ligands and their chelates were compared with the model ligating species 4,4,5,5,5-pentafluoro-1-phenyl-1,3-pentanedione with infrared and mass spectroscopy and proton nuclear magnetic resonance. 相似文献