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Lydia Kiroff 《Urban geography》2017,38(10):1573-1602
Auckland is New Zealand’s largest city with the largest concentration of creative sector employment and businesses in the country. This paper examines the spatial distribution of firms in the design creative subsector across the Auckland Region and in inner Auckland and ascertains the key determinants of firm location. The macrolevel findings indicate that the architectural and specialized design firms have similar spatial distribution patterns across the Auckland Region, while the advertising subsector demonstrates an extreme tendency toward spatial concentration only in inner Auckland. All three subsectors have a strong propensity to clustering within inner Auckland; however, one CBD (Central Business District) fringe area, Parnell outperforms the rest. The microlevel findings reveal hybridized creative clusters of uneven density. Parnell’s unique brand and place-specific characteristics were the key determinants of firm location which led to the spontaneous collocation of firms. These location decisions had the unintended consequence of creating agglomeration economies. 相似文献
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Ultramafic and mafic granulites from Archaean gneisses in N.W. Scotland (the Scourian) show evidence of two periods of granulite facies mineral growth. The first produced a high pressure clinopyroxene +garnet±plagioclase assemblage at an estimatedP-T of 12–15 kb and 1,000° C. Uplift of the complex caused partial breakdown of the garnet by reaction with clinopyroxene to produce orthopyroxene +plagioclase ±spinel±amphibole symplectites, at an estimatedP-T of 10–14 kb and 800°–900° C. Garnet stability is shown to depend on both whole-rock Fe/Mg ratios and onP-T conditions. The pressures imply crustal thicknesses in the Archaean of least 35–45 km. 相似文献
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Arsenic speciation in Mono Lake, California: Response to seasonal stratification and anoxia 总被引:1,自引:0,他引:1
James T. Hollibaugh Steve Carini Robert Jellison Gary LeCleir Lydia Vasquez 《Geochimica et cosmochimica acta》2005,69(8):1925-1937
Mono Lake is a closed-basin, alkaline, hypersaline lake located at the western edge of the Great Basin in eastern California. We studied the distribution of arsenic (As) species in the water column of Mono Lake between February and November, 2002. This period captured the seasonal progression from winter mixing, through summer thermal stratification, to autumn overturn. Arsenic speciation was determined by ion chromatography-inductively coupled-plasma-mass spectrometry of samples preserved in the field by flash-freezing in liquid nitrogen. We found that arsenic speciation was dominated (>90%) by arsenate when oxygen was detectable. Once levels fell below 6 μmol/L O2, arsenic speciation shifted to dominance by reduced species. Arsenate and arsenite co-occurred in a transition zone immediately below the base of the oxycline and low but significant concentrations of arsenate were occasionally detected in sulfidic hypolimnion samples. Thio-arsenic species were the dominant form of As found in sulfidic waters. Maxima of thio-arsenic species with stoichiometries consistent with mono-, di- and trithio-arsenic occurred in succession as sulfide concentration increased. A compound with a stoichiometry consistent with trithio-arsenic was the dominant As species (∼50% of total As) in high sulfide (2 mmol/L) bottom water. Lower concentrations of total As in bottom water relative to surface water suggest precipitation of As/S mineral phases in response to sulfide accumulation during prolonged anoxia. 相似文献
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Artificial tarballs were made in the laboratory from four crude petroleums. Relative to the parent petroleum, a decrease in aromatic hydrocarbon content for all samples was observed, as was a decrease in saturate content for three of four samples and an increase in compounds containing nitrogen, sulphur and oxygen for three samples. The asphaltene content also increased for three samples. The saturate, aromatic and asphaltic content of the artificial tarballs was compared to values for natural tarballs reported in the literature. 相似文献
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