USE OF REPLICATION AND SIGNAL-TO-NOISE RATIOS IN THE IDENTIFICATION AND ESTIMATION OF THE COMPOSITION OF LUBRICANT BASESTOCK MIXTURES USING ~(13)C NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY AND PROJECTION INTO PRINCIPAL COMPONENT/CANONICAL VARIATES SPACE     

JOHNM.DEANE  HALLIDAYJ.H.MacFIE  ALEXANDERG.KING 《地理学报(英文版)》1989,(1)

The theory of experimental error in analysis of mixture experiments by abstract factor analysis or targettransformation factor analysis is considered. The theoretical implications of using signal-to-noise ratios(as weights) or canonical variates analysis to reduce the level of imbedded error in the factor model areexamined. The approach is illustrated by application to ~(13)C NMR spectra of lubricant basestockmixtures.  相似文献   

The 1991 WMO International ozonesonde intercomparison at Vanscoy,Canada     

J.B. Kerr  H. Fast  C.T. McElroy  S.J. Oltmans  J.A. Lathrop  E. Kyro 《大气与海洋》2013,51(4):685-716

Abstract

An intercomparison of ozonesondes was held at Vanscoy, Saskatchewan, from 13 to 24 May 1991. The intercomparison, which was sponsored by the WMO and hosted by the Atmospheric Environment Service (AES) of Canada, was attended by scientists from six countries: Canada, Finland Germany, India, Japan and the United States. Four different makes of ozonesondes were used: the ECC sonde, the Brewer‐Mast sonde, the Indian ozonesonde and the Japanese RSH‐KC79 ozonesonde. These represent most of the sonde types that are in routine operation in the Global Ozone Observing System.

A balloon payload and telemetry system was developed to accommodate up to eight ozonesondes that could operate independently and transmit data simultaneously to a ground receiver. Ten flights were launched, each carrying 7 or 8 sondes, and a total of 65 successful profile measurements were made. The payloads were carried to altitudes between 35 and 40 km. The measured profiles are used to determine statistically meaningful evaluations of the different sonde types. The results compared with those from previous intercomparisons indicate that there has been a general improvement in performance for most of the types. In addition there appears to have been changes with time in the relative sensitivity to tropospheric ozone for different sonde types. This result should be considered when drawing conclusions regarding trends in tropospheric ozone.  相似文献   

Seminar on the marketing of fish: London,UK, November 1981     

J.K. McElroy 《Marine Policy》1982,6(2):154-156

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Radiative constraints on the energy budget of the tropical atmosphere     

K. Minschwaner  M. B. McElroy 《Planetary and Space Science》1992,40(12):1585-1597

A simple one-dimensional model is presented to describe the energy budget of the tropical atmosphere. Heating of the atmosphere is associated primarily with latent energy released due to precipitation in localized regions of intense cumulonimbus activity. Air transported to upper regions of the troposphere by cumulonimbus systems is returned to the surface over a large region of descent. Heat released by subsidence is balanced primarily by emission of radiation in the infrared. The model accounts for this energy balance, exploring specifically the constraints on permissible fluxes of mass and energy.

Results suggest that the strength of the background subsidence field in the tropics may be sensitive to surface temperature and to changes in atmospheric composition, specifically variations in the altitude distribution of H₂O and changes in the abundance of greenhouse gases such as CO₂. The mean level of detrainment of deep cumulonimbus clouds is found to increase with increasing surface temperature. This behavior is shown to be sensitive to atmospheric composition. The surface temperature for an atmosphere containing twice the present level of CO₂ is predicted to increase by 1.4K, about 25% less than the change obtained with models in which the lapse rate of temperature is specified at lower altitudes, where assumptions of radiative equilibrium would lead otherwise to a statically unstable condition.

Buoyancy considerations suggest that there may be an upper limit to the range of permissible values for surface temperature in the tropics. Models in which the subsidence mass flux is assumed constant with respect to altitude are found to be unable to maintain buoyancy for rising air in the face of heat released by descent when surface temperatures exceed about 312K.  相似文献   

Trophic transfer of benzo[a]pyrene metabolites between benthic marine organisms     

Anne E. McElroy  John D. Sisson 《Marine environmental research》1989,28(1-4)

This study was undertaken to determine the potential for trophic transfer of polycyclic aromatic hydrocarbon (PAH) metabolites from infaunal organisms to bottom-feeding fish. Winter flounder, Pseudopleuronectes americanus, were given single oral doses of ground polychaetes (Nereis virens), either treated with pure [¹⁴C]henzo[a]pyrene (BaP) or containing a mixture of naturally produced radiolabeled BaP and BaP metabolites. Fish were sacrificed 24 h after feeding and total accumulated radioactivity and metabolite class profiles determined in major organs. Metabolites produced by worms were absorbed by flounder, although as a percentage of dose given they were less available than parent BaP. Comparison of metabolite profiles in the worm diet and in target organs in the fish indicated that metabolites accumulated through the diet can be further modified by the prey organism and can lead to the formation of bound residues. These results demonstrate that PAH metabolites in the diet are available for accumulation. Furthermore, metabolites absorbed appear to be susceptible to metabolic alteration by consumer organisms.  相似文献   

Role of the mucous surface coat, dietary bulk and mucosal cell turnover in the intestinal disposition of benzo(a)pyrene (BaP)     

K. M. Kleinow  A. A. Smith  A. E. McElroy  J. E. Wiles 《Marine environmental research》1996,42(1-4)

The dispositon of ³H-benzo(a)pyrene (BaP) equivalents from the diet was examined at the lumen-mucosal cell interface of the proximal, medial and distal regions of the catfish intestine. ³H-BaP (500 μd, 20 μg/kg) was administered via gavage in maintenance diet to two groups of catfish. One group was fed daily after dosing while the other was fasted until collection of intestinal tissues. Autoradiography of cryosectioned tissues and computer-enhanced image analysis allowed examination of BaP disposition. BaP was found to selectively localize at high concentrations in the mucous surface coat and corresponding villi of the colon. Supplemental feeding of uncontaminated diet lowered BaP concentrations in these regions. In a similar but separate experiment, ³H-thymidine (666 μCi) was administered to two groups of catfish by i.p. injection to examine mucosal cell turnover in relation to BaP turnover. ³H-Thymidine incorporation was greatest in the distal regions of both fasted and fed groups. Thymidine dynamics indicated that feeding was related to only marginal changes in cell turnover, which suggests that losses in intravillus BaP with feeding may not be wholly explained by intestinal cell turnover. Results from this study suggest that the mucous surface coat of the intestine is a major factor in the regional disposition of dietary carcinogens and removal of BaP from this mucin layer is related to the intake of dietary bulk.  相似文献   

Slant Column Measurements of O3 and NO2 During the NDSC Intercomparison of Zenith-Sky UV-Visible Spectrometers in June 1996     

H. K. Roscoe  P. V. Johnston  M. Van Roozendael  A. Richter  A. Sarkissian  J. Roscoe  K. E. Preston  J-C. Lambert  C. Hermans  W. DeCuyper  S. Dzienus  T. Winterrath  J. Burrows  F. Goutail  J-P. Pommereau  E. D'Almeida  J. Hottier  C. Coureul  R. Didier  I. Pundt  L. M. Bartlett  C. T. McElroy  J. E. Kerr  A. Elokhov  G. Giovanelli  F. Ravegnani  M. Premuda  I. Kostadinov  F. Erle  T. Wagner  K. Pfeilsticker  M. Kenntner  L. C. Marquard  M. Gil  O. Puentedura  M. Yela  D. W. Arlander  B. A. Kastad Hoiskar  C. W. Tellefsen  K. Karlsen Tornkvist  B. Heese  R. L. Jones  S. R. Aliwell  R. A. Freshwater 《Journal of Atmospheric Chemistry》1999,32(2):281-314

In June 1996, 16 UV-visible sensors from 11 institutes measured spectra of the zenith sky for more than 10 days. Spectra were analysed in real-time to determine slant column amounts of O3 and NO2. Spectra of Hg lamps and lasers were measured, and the amount of NO2 in a cell was determined by each spectrometer. Some spectra were re-analysed after obvious errors were found. Slant columns were compared in two ways: by examining regression analyses against comparison instruments over the whole range of solar zenith angles; and by taking fractional differences from a comparison instrument at solar zenith angles between 85° and 91°. Regression identified which pairs of instruments were most consistent, and so which could be used as universal comparison instruments. For O3, regression slopes for the whole campaign agreed within 5% for most instruments despite the use of different cross-sections and wavelength intervals, whereas similar agreement was only achieved for NO2 when the same cross-sections and wavelength intervals were used and only one half-day's data was analysed. Mean fractional differences in NO2 from a comparison instrument fall within ±7% (1-sigma) for most instruments, with standard deviations of the mean differences averaging 4.5%. Mean differences in O3 fall within ±2.5% (1- sigma) for most instruments, with standard deviations of the mean differences averaging 2%. Measurements of NO2 in the cell had similar agreement to measurements of NO2 in the atmosphere, but for some instruments measurements with cell and atmosphere relative to a comparison instrument disagreed by more than the error bars.  相似文献   

Atmospheric composition: Influence of biology     

M.B. McElroy 《Planetary and Space Science》1983,31(9):1065-1074

The composition of the atmosphere is regulated by biological activity on a variety of time scales. Global biogeochemical cycles of nitrogen, carbon and sulfur are discussed with an emphasis on N₂O, NO, CO₂, CH₄ and SO₂. It is argued that Man is a major influence on the budget of these gases. His influence is attributed primarily to use of fossil fuels, to various aspects of agriculture and to the disposal of human and animal waste.  相似文献   

X Cainozoic rocks outside the Murray Basin     

C.L. Adamson  D.F. Branagan  L.R. Hall  C.T. McElroy  D.G. Moye  R.E. Relph 《Australian Journal of Earth Sciences》2013,60(1):543-557

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Hydrogen on venus: Exospheric distribution and escape     

J.M. Rodriguez  M.J. Prather  M.B. McElroy 《Planetary and Space Science》1984,32(10):1235-1255

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