Reply to “delusions of uniqueness and ineluctability” by J. Aitchison     

D. F. Watson 《Mathematical Geology》1991,23(2):279

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Infill sampling criteria to locate extremes   总被引：1，自引：0，他引：1  

Alan G. Watson  Randal J. Barnes 《Mathematical Geology》1995,27(5):589-608

Three problem-dependent meanings for engineering extremes are motivated, established, and translated into formal geostatistical (model-based) criteria for designing infill sample networks. (1) Locate an area within the domain of interest where a specified threshold is exceeded, if such areas exist. (2) Locate the maximum value in the domain of interest. (3) Minimize the chance of areas where values are significantly different from predicted values. An example application on a simulated dataset demonstrates how such purposive design criteria might affect practice.  相似文献   

Li zoning in zircon as a potential geospeedometer and peak temperature indicator     

Dustin Trail  Daniele J. Cherniak  E. Bruce Watson  T. Mark Harrison  Benjamin P. Weiss  Ian Szumila 《Contributions to Mineralogy and Petrology》2016,171(3):25

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An analytic method to account for drag in the Vinti satellite theory     

J. S. Watson  G. D. Mistretta  N. L. Bonavito 《Celestial Mechanics and Dynamical Astronomy》1975,11(2):145-177

In order to retain separability in the Vinti theory of Earth satellite motion when a nonconservative force such as air drag is considered, a set of variational equations for the orbital elements are introduced, and expressed as functions of the transverse, radial, and normal components of the nonconservative forces acting on the system. In this approach, the Hamiltonian is preserved in form, and remains the total energy, but the initial or boundary conditions and hence the Jacobi constants of the motion advance with time through the variational equations. In particular, the atmospheric density profile is written as a fitted exponential function of the eccentric anomaly, which adheres to tabular data at all, altitudes and simultaneously reduces the variational equations to definite integrals with closed form evaluations whose limits are in terms of the eccentric anomaly. The values of the limits for any arbitrary time interval are obtained from the Vinti program.Results of this technique for the case of the intense air drag satellites San Marco-2 and Air Force Cannonball are given. These results indicate that the satellite ephemerides produced by this theory in conjunction with the Vinti program are of very high accuracy. In addition, since the program is entirely analytic, several months of ephemerides can be obtained within a few seconds of computer time.  相似文献   

Diel feeding patterns and the development of food webs in pelagic 0-group cod (Gadus morhua L.), haddock (Melanogrammus aeglefinus L.), whiting (Merlangiusmerlangus L.), saithe (Pollachius virens L.), and Norway pout (Trisopterus esmarkii Nilsson) in the northern North Sea     

Bromley  P. J.; Watson  T.; Hislop  J. R. G. 《ICES Journal of Marine Science》1997,54(5):846-853

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Vancouver workshop: overview and synthesis     

Watson M 《Marine environmental research》2004,57(1-2):145-153

Investigators from the six PICES member nations conducted a May, 1999 interdisciplinary research assessment of Vancouver Harbour, BC, Canada. Sediment contaminants were analyzed at several sites along an assumed pollution gradient extending eastward into the harbour from the relatively less-impacted Howe Sound area (located outside and seaward, to the west). Subsets of a few representative benthic biota (English sole for general contaminants; specific mollusks for TBT) at the sampling sites were concurrently assessed for specific tissue contaminants. Measurements of biotic response to contaminants-across a wide spectrum of biological and ecosystem organization, and ranging from selected biomarkers and tissue responses, to observations at the organism and community level-were likewise conducted. Parameters examined included: P-450 expression, EROD induction and histopathologic assessment of toxicopathic liver lesions in English sole; prevalence and frequency of imposex in neogastropods; perturbations in benthic community responses to pollutants; tissue assays of various bivalve shellfish species for PSP. Results affirmed a consistent east-to-west trend in declining contaminant-associated effects, across a range of biological assessments, thus providing strong evidence that these effects are pollution-related. Specific findings revealed a significant distortion of benthic community structure along the pollution gradient, as well as biomarker evidence of histological and biochemical stress in English sole from central and inner harbour sites. Although the study reaffirms prior assumptions that various species of neogastropods have been extirpated from the harbour, most likely from the antifoulant uses of tributyltin, some of the adverse impacts from TBT may be declining. Also noted were strong biochemical inferences that sediments in the relatively "uncontaminated" Howe Sound, may well contain significant P450-inducing pollutants which were not included as analytes in the design of this limited and preliminary assessment. During the brief sampling period, PSP contamination did not appear to be a significant issue for the harbour.  相似文献   

A non-destructive assessment of the exposure of crabs to PAH using ELISA analyses of their urine and haemolymph     

Fillmann G  Watson GM  Francioni E  Readman JW  Depledge MH 《Marine environmental research》2002,54(3-5):823-828

Urine and haemolymph can be repeatedly sampled from crabs with no (or limited) damage to the organism. Their analysis offers a measure of the animals' exposure to biologically available contaminants. Shore crabs (Carcinus maenas) were exposed to the PAHs phenanthrene and pyrene at concentrations ranging from 20 to 200 microg l(-1). After 48 h, urine and haemolymph samples were taken and analysed using ELISA and UV-fluorescence spectrophotometry. High correlations were recorded between the two sets of results from the urine analyses (r2 = 0.83 for phenanthrene and r2 = 0.88 for pyrene). Contaminant concentrations were much lower in haemolymph than in the urine. Analyses of urine taken from crabs collected from clean and contaminated sites confirm the suitability of these analyses for environmentally exposed organisms. Again, a good correlation was recorded between the ELISA and spectrofluorimetric analysis (r2 = 0.83). In this instance, difficulties were experienced with haemolymph analyses owing to a lack of sensitivity.  相似文献   

Diffusion in fluid-bearing and slightly-melted rocks: experimental and numerical approaches illustrated by iron transport in dunite     

E. Bruce Watson 《Contributions to Mineralogy and Petrology》1991,107(4):417-434

Bulk diffusion of iron in synthetic dunites containing 1–6 vol.% fluid or melt at 10 kbar (1 GPa) and 900°–1300° C was examined by encapsulating the samples in platinum, which served as a sink for iron. The rate of iron loss from the dunite was found to depend strongly upon the identity of the fluid, which was varied from CO₂ and H₂O to melts of basaltic and sodium carbonate composition. Carbon dioxide in amounts up to 4 vol.% has no effect upon bulk iron diffusion because it exists in the dunite are isolated pores. The interconnected nature of H₂O, basaltic melt, and carbonate melt, on the other hand, results in marked enhancement of bulk-rock Fe diffusion that is correlated with the diffusivity and solubility of olivine components in the fluid. At 1300° C, 4–5 vol.% of either water or basaltic melt increases the effective bulk diffusivity from the fluidabsent value of 10^-10 cm²/s to 10^-8 cm²/s. A single experiment involving a similar volume fraction of carbonate melt yielded a minimum bulk diffusivity of 10^-7–10^-6 cm²/s. This remarkably high value is attributable to the concurrent high diffusivity and high solubility of olivine components in molten carbonate H₂O has a high diffusivity, estimated at 10^-4 cm²/s in this study, and basaltic melt can dissolve large amounts of olivine, but neither possesses these two qualities in combination. Bulk transport of Fe in dunite containing <2 vol.% of pure H₂O is independent of olivine grain size for samples having an average grain diameter of <10 m to 60 m. This is probably because bulk diffusion specifically in these H₂O-bearing samples is ratelimited by the flux (which is proportional to concentration) of olivine components in the fluid. Given a constant fluid volume fraction, the effect of reducing the grain size is to increase the number of fluid-filled channels, but at the same time to decrease their average aperture, thus keeping constant the cross-sectional area through which the diffusional flux occurs. (Independence of bulk diffusivity from grain size is not anticipated for rocks containing melt, in which the silicate components are much more soluble.) In numerical (finite difference) simulations of selected laboratory experiments, the bulk Fe transport process was modeled as diffusion in fluid-filled tubules of triangular cross-section that are supplied by volume diffusion from contacting olivine grains with which they are in surface equilibrium. Applying a tortuosity factor of 1.7 brings the numerically computed diffusional loss profiles for experiments containing basaltic melt into near-coincidence with the experimentally-determined curves. This success in reproducing the experimental results lends credence to the interpretation of the bulk diffusional loss profiles as composites of gradients due to volume, grain-boundary and fluid-phase diffusion.  相似文献   

Absolute diffuse calibration of IRAC through mid-infrared and radio study of H ii regions     

Martin Cohen  Anne J. Green  Marilyn R. Meade  Brian Babler  Rémy Indebetouw  Barbara A. Whitney  Christer Watson  Mark Wolfire  Mike J. Wolff  John S. Mathis  Edward B. Churchwell 《Monthly notices of the Royal Astronomical Society》2007,374(3):979-998

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Using local infrasound arrays to detect plunging snow avalanches along the Milford Road,New Zealand (Aotearoa)     

Watson  Leighton M.  Carpenter  Brad  Thompson  Kevin  Johnson  Jeffrey B. 《Natural Hazards》2022,111(1):949-972

Natural Hazards - Snow avalanches pose a hazard in alpine environments. There is a need to improve monitoring capabilities in order to reliably detect and locate avalanche activity, which will help...  相似文献