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61.
Harry J. Schuler 《The Professional geographer》1979,31(2):146-156
Empirical testing of a decision model yields insights concerning the ways in which shoppers process information about grocery stores. Confirming hypotheses from the literature on consumer preferences, the results show that respondents are primarily concerned with quality and price of merchandise and that behavior is directly linked to derived utility measures. Clustering of the subjects discloses subtle differences among consumer groups in their approaches to evaluating the attributes of grocery stores. 相似文献
62.
The gravitational potential due to uniform disks and rings 总被引:1,自引:0,他引:1
The gravitational potential due to thin uniform disks and rings is obtained in closed form in terms of complete elliptic integrals. 相似文献
63.
Andrew W. BECK Kees C. WELTEN Harry Y. McSWEEN Jr. Christina E. VIVIANO Marc W. CAFFEE 《Meteoritics & planetary science》2012,47(6):947-969
Abstract— Nine howardites and two diogenites were recovered from the Pecora Escarpment Icefield (PCA) in 2002. Cosmogenic radionuclide abundances indicate that the samples are paired and that they constituted an approximately 1 m (diameter) meteoroid prior to atmospheric entry. At about 1 m in diameter, the PCA 02 HED group represents one of the largest single pre‐atmospheric pieces of the Vestan surface yet described. Mineral and textural variations were measured in six of the PCA 02 howardites to investigate meter‐scale diversity of the Vestan surface. Mineral compositions span the range of known eucrite and diogenite compositions. Additional non‐diogenitic groups of Mg‐ and Fe‐rich olivine are observed, and are interpreted to have been formed by exogenic contamination and impact melting, respectively. These howardites contain olivine‐rich impact melts that likely formed from dunite‐ and harzburgite‐rich target rocks. Containing the first recognized olivine‐rich HED impact melts, these samples provide meteoritic evidence that olivine‐rich lithologies have been exposed on the surface of Vesta. Finally, we present a new method for mapping distributions of lithologies in howardites using 8 elemental X‐ray maps. Proportions of diogenite and eucrite vary considerably among the PCA 02 howardites, suggesting they originated from a heterogeneous portion of the Vestan surface. While whole sample modes are dominated by diogenite, the finer grain size fractions are consistently more eucritic. This discrepancy has implications for near‐infrared spectral observations of portions of Vesta’s surface that are similar to the PCA 02 howardites, as the finer grained eucritic material will disproportionately dominate the spectra. 相似文献
64.
Harry Y. McSWEEN Lee R. RICIPUTI Bruce A. PATERSON 《Meteoritics & planetary science》1997,32(1):51-54
Abstract— The Kaidun meteorite contains carbonaceous chondrite (CM1) clasts that have been highly altered by reactions with hydrothermal fluids. Pyrrhotite in these clasts occurs as unusual needles wrapped by sheaths of phyllosilicate, and pentlandite forms veins that crosscut aggregates of phyllosilicate and garnet but not pyrrhotite. The isotopic compositions of S (δ34SCDT) in individual sulfide grains, measured by ion micro-probe, are fractionated compared to troilite in ordinary chondrites. The S in Kaidun sulfides is isotopically light (as much as ?4.2% for pyrrhotite and ?5.7%0 for pentlandite), unlike sulfides in other carbonaceous chondrites, which are enriched in 34S. The unusual S-isotopic composition of these texturally unique sulfides supports the hypothesis that Kaidun CM1 clasts were pervasively altered under extreme thermal conditions, possibly by fluids that had lost isotopically heavy SO2. 相似文献
65.
Additional studies of the ion composition results obtained from the OGO-6 satellite support earlier observations of irregularities in the distribution of H+ and He+ within the light ion trough near L = 4, which has been associated with the plasmapause. These irregularities are in the form of sub-troughs superimposed upon the major mid latitude decrease of the light ions. In the sub-troughs, ionization depletions and recoveries of as much as an order of magnitude are observed within a few degrees of latitude, usually exhibited in a pattern which changes significantly with longitude as the Earth rotates beneath the relatively fixed satellite orbit. The location and properties exhibited by these sub-troughs appear to be consistent with the concept of a plasmasphere distortion in the form of “plasmatails” resulting from the combined effects of magnetospheric convection plus corotation. Like the light ion trough, the “plasmatail” irregularity in H+ may be obscured on the day side by the dominant topside distribution of O+. Consequently, these light ion irregularities are seen as an important factor for studies of plasmapause-trough relationships. 相似文献
66.
Harry Sendner 《Ocean Dynamics》1952,5(4):199-204
Zusammenfassung Bei der im Folgenden beschriebenen Methode zur Berechnung der Stromellipsenelemente werden die Summen und Differenzen der Hauptachsen bzw. ihrer Richtungen und Phasen als Beträge bzw. Richtungen zweier Vektoren bestimmt. Die Komponenten dieser Vektoren sind wieder Summen und Differenzen von vier Konstanten, die man bei der harmonischen Analyse der Stromkomponenten bezüglich der betreffenden Tide gewinnt. Eine andere Berechnungsmethode geht von den harmonischen Konstanten der Stromkomponenten aus und benutzt trigonometrische Funktionen komplexen Arguments. Zum Schluß werden Beziehungen zwischen den Elementen der Stromellipse und denen der Gefällsellipse aufgestellt unter der Voraussetzung, daß der Zusammenhang zwischen horizontalen und vertikalen Gezeiten sich durch die linearisierten hydrodynamischen Grundgleichungen darstellen läßt.
A method of calculating tidal stream and gradient ellipses
Summary In the following paper a method of calculating the elements of tidal stream ellipses is described by which the sums and differences of the major axes or their directions and phases are determined as the scalar quantities or directions of two vectors. The components of these vectors, on their turn, are sums and differences of four constants obtained by the harmonic analysis of the stream components with regard to the respective tide. Another calculating method proceeds from the harmonic constants of the stream components and employs trigonometric functions of complex arguments. Finally, on the supposition that the relation between horizontal and vertical tides may be represented by the linearized fundamental hydrodynamic equations, relations are established between the elements of the tidal stream ellipse and those of the gradient ellipse.
Mode de calcul des ellipses du courant de marée et du gradient
Résumé Le mode de calcul des éléments des ellipses du courant expliqué ci-dessous demande que les sommes et les différences des grandaxes ou leurs directions et leurs phases soient déterminées comme grandeurs scalaires ou comme directions de deux vecteurs. Les composantes de ces vecteurs sont, de leur part, les sommes ou les différences de quatre constantes qui résultent de l'analyse harmonique des composantes de courant de la marée en question. Une autre méthode de calcul part des constantes harmoniques des composantes de courant et emploie des fonctions trigonométriques à l'argument complexe. Enfin, pourvu que la relation entre les composantes horizontales et verticales puisse être représentée à l'aide des équations hydrodynamiques fondamentales linéarisées, des relations entre les éléments de l'ellipse du courant et ceux de l'ellipse du gradient sont établies.相似文献
67.
Amber J. Roesler Christopher H. Gammons Gregory K. Druschel Harry Oduro Simon R. Poulson 《Aquatic Geochemistry》2007,13(3):211-235
Unlike the majority of the water in the flooded mine complex of Butte Montana, which includes the highly acidic Berkeley pit
lake, groundwater in the flooded West Camp underground mine workings has a circum-neutral pH and contains at least 8 μM aqueous
sulfide. This article examines the geochemistry and stable isotope composition of this unusual H2S-rich mine water, and also discusses problems related to the colorimetric analysis of sulfide in waters that contain FeS(aq) cluster compounds. The West Camp mine pool is maintained at a constant elevation by continuous pumping, with discharge water
that contains elevated Mn (90 μM), Fe (16 μM), and As (1.3 μM) but otherwise low metal concentrations. Dissolved inorganic
carbon in the mine water is in chemical and isotopic equilibrium with rhodochrosite in the mineralized veins. The mine water
is under-saturated with mackinawite and amorphous FeS, but is supersaturated with Cu- and Zn-sulfides. However, voltammetry
studies show that much of the dissolved sulfide and ferrous iron are present as FeS(aq) cluster molecules: as a result, the free
concentration of the West Camp water is poorly constrained. Concentrations of dissolved sulfide determined by colorimetry
were lower than gravimetric assays obtained by AgNO3 addition, implying that the FeS(aq) clusters are not completely extracted by the Methylene Blue reagent. In contrast, the clusters are quantitatively extracted
as Ag2S after addition of AgNO3. Isotopic analysis of co-existing aqueous sulfide and sulfate confirms that the sulfide was produced by sulfate-reducing
bacteria (SRB). The H2S-rich mine water is not confined to the immediate vicinity of the extraction well, but is also present in flooded mine shafts
up to 3 km away, and in samples bailed from mine shafts at depths up to 300 m below static water level. This illustrates that
SRB are well established throughout the southwestern portion of the extensive (>15 km3) Butte flooded mine complex. 相似文献
68.
Constraints from high-pressure veins in eclogites on the composition of hydrous fluids in subduction zones 总被引:3,自引:0,他引:3
Hydrous high-pressure veins formed during dehydration of eclogites in two paleo-subduction zones (Trescolmen locality in the Adula nappe, central Alps and Münchberg Gneiss Massif, Variscan fold belt, Germany) constrain the major and trace element composition of solutes in fluids liberated during dehydration of eclogites. Similar initial isotopic compositions of veins and host eclogites at the time of metamorphism indicate that the fluids were derived predominantly from the host rocks. Quartz, kyanite, paragonite, phengite, zoisite and omphacite are the dominant minerals in the veins. The major element compositions of the veins are in agreement with experimental evidence indicating that the composition of solutes in such fluids is dominated by SiO2 and Al2O3. Relative to N-MORB, the veins show enrichments of Cs, Rb, Ba, Pb, and K, comparable or slightly lower abundances of Sr, U, and Th, and very low abundances of Nd, Sm, Zr, Nb, Ti and Y. The differential fractionation of highly incompatible elements such as K, U and Th in the veins, as well as the presence of hydrous minerals in the eclogites rule out partial melting as a cause for vein formation. These results confirm previous suggestions that fluids derived from subducted basalt may have low abundances of high field strength elements, rare earth elements and Y. Variable vein-eclogite enrichment factors of incompatible alkalis and to a lesser extent Pb appear to reflect mineralogical controls (phengite, epidote-group minerals) on partitioning of these elements during dehydration of eclogite in subduction zones. However, abundance variations of incompatible elements in minerals from eclogites suggest that the composition of fluids released from eclogites at temperatures <700°C may not reflect true equilibrium partitioning during dehydration. Simple models for the trace elements U and Th indicate the relative importance of the basaltic and sedimentary portions of subducted oceanic crust in producing the characteristic chemical signatures of these elements in convergent plate margin volcanism. 相似文献
69.
Quantitative analysis of the impact of droughts and floods on internal wars in China over the last 500 years 总被引:1,自引:0,他引:1
Although many large-N quantitative studies have evidenced the adverse effects of climatic extremes on social stability in China during the historical period, most of them rely on temperature and precipitation as major explanatory variables, while the influence of floods and droughts on social crises is rarely measured. Furthermore, a comparison of the climate-society nexus among different geographic regions and at different temporal scales is missing in those studies. To address this knowledge gap,this study examines quantitatively the influence of floods and droughts on internal wars in three agro-ecological(rice, wheat,and pastoral) regions in China in AD1470–1911. Poisson regression and wavelet transform coherence analyses are applied to allow for the non-linear and non-stationary nature of the climate-war nexus. Results show that floods and droughts are significant in driving internal wars in historical China, but are characterized by strong regional variation. In the rice region, floods trigger internal wars at the inter-annual and multi-decadal time scales. In the wheat region, both floods and droughts cause internal wars at the inter-annual and multi-decadal time scales. In the pastoral region, internal wars are associated with floods only at the multi-decadal time scale. In addition, the multi-decadal coherence between hydro-climatic extremes and internal wars in all three of the agro-ecological regions is only significant in periods in which population density is increasing or the upper limit of regional carrying capacity is being reached. The above results imply that the climate-war nexus is mediated by regional geographic factors such as physical environmental setting and population pressure. Hence, we encourage researchers who study the historical human-climate relationship to boil down data according to geographic regions in the course of statistical analysis and to examine each region individually in follow-up studies. 相似文献
70.
Sebastian J. Pitman Harry M. Jol James Shulmeister Deirdre E. Hart 《地球表面变化过程与地形》2019,44(8):1610-1617
Beach ridge stratigraphy can provide an important record of both sustained coastal progradation and responses to events such as extreme storms, as well as evidence of earthquake induced sediment pulses. This study is a stratigraphic investigation of the late Holocene mixed sand gravel (MSG) beach ridge plain on the Canterbury coast, New Zealand. The subsurface was imaged along a 370 m shore-normal transect using 100 and 200 MHz ground penetrating radar (GPR) antennae, and cored to sample sediment textures. Results show that, seaward of a back-barrier lagoon, the Pegasus Bay beach ridge plain prograded almost uniformly, under conditions of relatively stable sea level. Nearshore sediment supply appears to have created a sustained sediment surplus, perhaps as a result of post-seismic sediment pulses, resulting in a flat, morphologically featureless beach ridge plain. Evidence of a high magnitude storm provides an exception, with an estimated event return period in excess of 100 years. Evidence from the GPR sequence combined with modern process observations from MSG beaches indicates that a palaeo-storm initially created a washover fan into the back-barrier lagoon, with a large amount of sediment simultaneously moved off the beach face into the nearshore. This erosion event resulted in a topographic depression still evident today. In the subsequent recovery period, sediment was reworked by swash onto the beach as a sequence of berm deposit laminations, creating an elevated beach ridge that also has a modern-day topographic signature. As sediment supply returned to normal, and under conditions of falling sea level, a beach ridge progradation sequence accumulated seaward of the storm feature out to the modern-day beach as a large flat, uniform progradation plain. This study highlights the importance of extreme storm events and earthquake pulses on MSG coastlines in triggering high volume beach ridge formation during the subsequent recovery period. © 2019 John Wiley & Sons, Ltd. 相似文献