Upper limits on micro-mini black holes     

Tony Rothman  Richard Matzner 《Astrophysics and Space Science》1981,75(2):229-236

The equations determining cosmic nucleosynthesis up to⁴He are modified to take account of black-hole evaporation during nucleosynthesis. Numerical calculation shows that deuterium is enhanced by the presence of these micro-mini black holes (mBH); but very high-density universes are difficult to reconcile with observations, even with a very large abundance of mBH.  相似文献   

Determination of the Optimum Sampling Intervals in Sediment Pore Waters Using the Autocovariance Function     

John W. Morse  Steven F. Dimarco  Karen S. Sell  Andrew B. Hebert 《Aquatic Geochemistry》2003,9(1):41-57

An approach to scaling that has found considerable utility inthe field of physical oceanography is based on theauto-covariance function (ACF). It is demonstrated to alsobe useful in determining the characteristic length scale of thedominant variance of dissolved sulfide and ferrous iron inanoxic pore waters. The method begins with the analysisof a data series in which the measurement sampling intervalis smaller than the expected length scales. A least squarespolynomial fit to the data representing a background field isthen removed from the data series making possible the analysisof the variability superimposed on the background field. Thecharacteristic length scale is then defined as the distancein which the measurements become uncorrelated. This usuallyoccurs at a significance-level or zero-crossing of the ACF.Characteristic lengths obtained for sediments from a varietyof coastal environments are not distinguishable betweensecond and third order polynomial fits with average valuesand standard deviations of, respectively, 7.0 ± 2.7 mm and6.1 ± 2.3 mm. These values are close to the typical burrowdiameter of 7.5 mm used by Aller (1978) in his bioirrigationmodel for sediment diagenesis. These results indicate thatmacrofauna dwelling in the sediment are probably responsiblefor the variability, although in the seagrass meadow rhizomesmay also play a role.  相似文献   

The Linton Award 2002     

Tony Parsons 《地球表面变化过程与地形》2003,28(2):113-114

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Pyrite formation under conditions approximating those in anoxic sediments: II. Influence of precursor iron minerals and organic matter     

John W. Morse  Qiwei Wang 《Marine Chemistry》1997,57(3-4)

In the paper (Wang and Morse, 1996) that preceded this study, we presented results of experiments performed using a silica gel crystal growth technique to produce pyrite under conditions approximating those commonly occurring in anoxic marine sediments. The primary focus of that study was on the chemical pathways that pyrite formation follows and how differing conditions influenced reaction kinetics and morphology of pyrite crystals. In this paper, we present results of further long-term (up to 1 y) studies of pyrite formation, using the silica gel experimental technique, in which we investigated the role that different precursor iron (hydr)oxide minerals and marine organic matter play in pyrite formation. The minerals studied were akaganeite (β-FeOOH), ferrihydrite (Fe₅HO₈ · 4H₂O), goethite (α-FeOOH), hematite (α-Fe₂O₃), lepidocrocite (γ-FeOOH), and magnetite (Fe₃O₄). Marine organic matter used in this study was freeze-dried plankton collected from near-surface water in the Gulf of Mexico. The influence of precursor iron (hydr)oxide mineralogy, although important for initial iron sulfidization rates, was relatively minor compared to other variables, such as solution pH and sulfide concentration, in controlling the rate of pyrite formation. Consequently, major variations in the observed rate of pyritization of different iron (hydr)oxide minerals in sediments (e.g., Canfield and Berner, 1987) may reflect large differences in surface areas of the minerals rather than their intrinsic reactivity and is a confirmation of the estimates of Canfield et al. (1992) that most iron oxides have similar reactivity. The presence of marine organic matter (freeze-dried plankton) caused an increase in the sulfidization rate of goethite and a major (about 20 ×) decrease in the rate of pyrite formation. This can be interpreted as indicating that organic matter-iron interactions are important in both iron (hydr)oxide dissolution, and pyrite nucleation and growth. A possible explanation for this behavior is that dissolved organic matter produced during the long experiments (up to 1 year) increased the rate of goethite dissolution while inhibiting pyrite nucleation and growth by complexing iron. The lessons learned in the study of other mineral reaction kinetics (e.g., calcite and aragonite), that rates determined in pure inorganic systems, may not always be reliably applied to natural systems where organic matter can significantly influence mineral dissolution and growth rates, are, alas, repeated here for pyrite.  相似文献   

The steady-state calcium carbonate ion activity product of recent shallow water carbonate sediments in seawater: a comparison of field observations and laboratory experiments     

Lawrence D. Bernstein  John W. Morse 《Marine Chemistry》1985,15(4):311-326

Closed system equilibration experiments between natural seawater and shallow water calcium carbonate-rich sediments from the Bahamas yielded steady-state calcium carbonate ion activity products (CCIAP). Results obtained from initially supersaturated and undersaturated solutions were in good agreement. Experiments conducted with the addition of a biocide and/or the destruction of sediment organic matter gave results similar to those obtained in systems where these treatments were not used. Excellent agreement was also found between CCIAP values for 8 day and more than 50 day equilibration times. Our results, therefore, meet the major criteria for at least metastable equilibrium between the solution and carbonate sediment.Fine-grained samples produced a CCIAP close to the value predicted for aragonite, which is the major carbonate phase in all samples. Coarse-grained sediments produced larger CCIAP values of up to 2.8 times that predicted for aragonite equilibrium. The CCIAP for the coarse-grained sediments is probably produced by high-Mg calcite which is a significant component of these sediments. Oolite samples were among the coarse-grained sediment samples studied. They also produced results much greater than expected for aragonite equilibrium. This brings into question their use as material for measuring aragonite solubility as has been done in the past.The CCIAP measured in the laboratory experiments are in good agreement with field observations of pore-water CCIAP values from the fine-grained sediments. Coarse-grained sediments showed greater variability, with higher CCIAP values generally occurring in the pore waters than in the laboratory experiments. Since the overlying waters were always at a higher CCIAP than the pore waters, the major factor causing this difference is believed to be the short residence time of pore waters in the coarse-grained sediments, which is the result of the high-energy hydrodynamic environments in which they reside.  相似文献   

Black sea oceanography : E. Izda and J.W. Murray (Editors). NATO ASI Series C: Mathematical and Physical Sciences - Vol. 351. Kluwer Academic Publishers, Dordrecht, 1991, hardcover, xv + 487 pp, US $149. ISBN 0-7923-1515-4     

John W. Morse 《Marine Chemistry》1993,42(3-4)

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Parametric vertical coordinate formulation for multiscale, Boussinesq, and non-Boussinesq ocean modeling   总被引：2，自引：1，他引：2  

Y. Tony Song  Thomas Y. Hou 《Ocean Modelling》2006,11(3-4):298-332

Two physical parameters are introduced into the basic ocean equations to generalize numerical ocean models for various vertical coordinate systems and their hybrid features. The two parameters are formulated by combining three techniques: the arbitrary vertical coordinate system of Kasahara [Kasahara, A., 1974. Various vertical coordinate systems used for numerical weather prediction. Mon. Weather Rev. 102, 509–522], the Jacobian pressure gradient formulation of Song [Song, Y.T., 1998. A general pressure gradient formation for ocean models. Part I: Scheme design and diagnostic analysis. Mon. Weather Rev. 126 (12), 3213–3230], and a newly introduced parametric function that permits both Boussinesq (volume-conserving) and non-Boussinesq (mass-conserving) conditions. Based on this new formulation, a generalized modeling approach is proposed. Several representative oceanographic problems with different scales and characteristics––coastal canyon, seamount topography, non-Boussinesq Pacific Ocean with nested eastern Tropics, and a global ocean model––have been used to demonstrate the model’s capabilities for multiscale applications. The inclusion of non-Boussinesq physics in the topography-following ocean model does not incur computational expense, but more faithfully represents satellite-observed ocean-bottom-pressure data. Such a generalized modeling approach is expected to benefit oceanographers in solving multiscale ocean-related problems by using various coordinate systems on the same numerical platform.  相似文献   

Adaptive behaviour of herring schools in the Norwegian Sea as revealed by high-resolution sonar   总被引：1，自引：6，他引：1  

Pitcher  Tony J.; Misund  Ole Arve; Ferno  Anders; Totland  Bjorn; Melle  Vebjorn 《ICES Journal of Marine Science》1996,53(2):449-452

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Critical network infrastructure analysis: interdiction and system flow   总被引：5，自引：1，他引：4  

Alan T. Murray  Timothy C. Matisziw  Tony H. Grubesic 《Journal of Geographical Systems》2007,9(2):103-117

Effective management of critical network infrastructure requires the assessment of potential interdiction scenarios. Optimization approaches have been essential for identifying and evaluating such scenarios in networked systems. Although a primary function of any network is the distribution of flow between origins and destinations, the complexity and difficulty of mathematically abstracting interdiction impacts on connectivity or flow has been a challenge for researchers. This paper presents an optimization approach for identifying interdiction bounds with respect to connectivity and/or flow associated with a system of origins and destinations. Application results for telecommunications flow are presented, illustrating the capabilities of this approach.

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Alan T. Murray (Corresponding author)Email:

Timothy C. MatisziwEmail:

Tony H. GrubesicEmail:

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A Textural Record of Solidification and Cooling in the Skaergaard Intrusion, East Greenland   总被引：2，自引：0，他引：2  

Holness  Marian B.; Tegner  Christian; Nielsen  Troels F. D.; Stripp  Gemma; Morse  Stearns A. 《Journal of Petrology》2007,48(12):2359-2377

The clinopyroxene–plagioclase–plagioclase dihedralangle, _cpp, in gabbroic cumulates records the time-integratedthermal history in the sub-solidus and provides a measure oftextural maturity. Variations in _cpp through the Layered Seriesof the Skaergaard intrusion, East Greenland, demonstrate thatthe onset of crystallization of clinopyroxene (within LZa),Fe–Ti oxides (at the base of LZc) and apatite (at thebase of UZb) as liquidus phases in the bulk magma is recordedby a stepwise increase in textural maturity, related to an increasein the contribution of latent heat to the total heat loss tothe surroundings and a reduction in the specific cooling rateat the crystallization front of the intrusion. The onset ofboth liquidus Fe–Ti oxide and apatite crystallizationis marked by a transient increase in textural maturity, probablylinked to overstepping before nucleation. Textural maturationat pyroxene–plagioclase–plagioclase triple junctionseffectively ceases in the uppermost parts of the Layered Seriesas a result of the entire pluton cooling below the closure temperaturefor dihedral angle change, which is 1075°C. Solidificationof the Layered Series of the Skaergaard intrusion occurred viathe upwards propagation of a mush zone only a few metres thick. KEY WORDS: magma; partial melting; asthenosphere; olivine; mantle  相似文献