Across the pond: container shipping on the North Atlantic in the era of globalisation   总被引：1，自引：0，他引：1  

Brian Slack 《GeoJournal》1999,48(1):9-14

This paper describes the development of containerisation in one of the most important theatres of maritime trade, the North Atlantic. As the original hearth of containerisation, it has been an area of experimentation and evolution for a technology that has burst around the world. Although over the last decade the Atlantic has been superceded by the Pacific Ocean as the major market focus for containers, it still is an important market arena. The emergence of global shipping networks is tending to favour the Atlantic once again. The paper provides an analysis of these recent developments. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

“Rust” contamination of formation waters from producing wells     

Brian Hitchon   《Applied Geochemistry》2000,15(10):1106

In the Alberta Basin there is a significant difference in the content of Fe between formation waters from drillstem tests and formation waters from producing wells. This was demonstrated using a data set comprising 525 formation waters from drillstem tests and 107 formation waters from producing wells. Both a cross-plot of Mn and Fe in the two sets of formation waters and box plots of the same data sets showed that formation waters from producing wells have dominantly Fe>Mn, compared with those from drillstem tests which are characterized by Mn>Fe. Suspecting that “rust” contamination from well casing and ancillary equipment was the cause, the pH values of the samples were compared to see if the two data sets also differed in pH. It was demonstrated that not only are formation waters from drillstem tests less acidic than those from producing wells, but there is a systematic statistical trend of increasing acidity with age of the strata (temperature, depth, and increased amounts of the acid gases — H₂S and CO₂). The difference between the pH of formation waters from drillstem tests and producing wells is attributed to the partial scrubbing of the acid gases from the fluids produced during the drillstem test; this results in less acidic formation waters. Vanadium may also be enhanced in formation waters from producing wells. This note reports these differences and cautions too much reliance on values for Fe in waters from producing wells.  相似文献   

The Jury is Still Out on Global Warming Potentials   总被引：1，自引：1，他引：0  

Brian C. O'Neill 《Climatic change》2000,44(4):427-443

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Tectonic facies and the archipelago-accretion process of the West Kunlun,China     

Xiao Wenjiao  Hou Quanlin  Li Jiliang  Brian F. Windley  Hao Jie  Fang Aiming  Zhou Hui  Wang Zhihong  Chen Hanlin  Zhang Guocheng  Yuan Chao 《中国科学D辑(英文版)》2000,43(1):134

A tectonic facies investigation carried out in the West Kunlun, China allows us to have worked out a tectonic model of orogen. The tectonic facies, from the north to the south, are composed of the following: 1. Southern Tarim tectonic realm; 2. North Kudi magmatic arc; 3. Kudi mélange; 4. Kudi micro-continent; 5. main shear zone; 6. Xianan Bridge calc alkaline complex; 7. Mazar-Kangxiwar mélange-accretion complex; and 8. Tianshuihai foreland fold-thrust belt. The tectonic facies 1»5 recorded the history of the northward subduction of the Prototethys and southward accretion of Eurasia in the Late Proterozoic-Early Paleozoic time, while the tectonic facies 6»8 recorded the history of the northward subduction of the Paleotethys and southward accretion of Eurasia in the Late Paleozoic-Early Mesozoic time, that of the tectonic evolution of the passive margin of the Qiangtang block, and that of the docking, and the final amalgamation of the Qiangtang block to the Eurasian continent. The tectonic facies investigation has indicated that a complicated archipelago-accretion orogenesis took place in the West Kunlun orogen, which was the important character of southward growth of the Eurasian continent.  相似文献   

Sensitivity study using a genetic algorithm: inversion of amplitude variations with slowness     

Ying Ji  Satish C. Singh  Brian E. Hornby 《Geophysical Prospecting》2000,48(6):1053-1073

A sensitivity study of elastic parameters in amplitude-variation-with-slowness (AVS) for small- and large-offset seismic data is presented. In order to handle the non-linearity associated with waveform or amplitude beyond the critical slowness, an inversion algorithm based on Bayes' theory is used. A genetic algorithm was used to obtain the a posteriori probability density (PPD) function. The sensitivity analysis is performed on synthetic data containing P-wave as well as converted S-wave reflections. Four different two-layer models, which represent the typical range of AVS responses associated with the gas-sands normally encountered in exploration, were used to examine how well the elastic parameters can be inverted for different parametrizations by comparing the PPD functions. The sensitivity study results suggest that including wide-angle data in the inversion can greatly enhance the quality of inversion. The converted S-wave reflections can provide valuable extra information that can be used to extract elastic parameters. The results with noisy data demonstrate that the contrast of density and three velocity ratios can be estimated robustly with wide-angle reflection data.  相似文献   

The Roles of Reconnected Flux and Overlying Fields in CME Speeds     

Minda Deng  Brian T. Welsch 《Solar physics》2017,292(1):17

Researchers have reported i) correlations of coronal mass ejection (CME) speeds and the total photospheric magnetic flux swept out by flare ribbons in flare-associated eruptive events, and, separately, ii) correlations of CME speeds and more rapid decay, with height, of magnetic fields in potential-field coronal models above eruption sites. Here, we compare the roles of both ribbon fluxes and the decay rates of overlying fields in a set of 16 eruptive events. We confirm previous results that higher CME speeds are associated with both higher ribbon fluxes and more rapidly decaying overlying fields. We find the association with ribbon fluxes to be weaker than a previous report, but stronger than the dependence on the decay rate of overlying fields. Since the photospheric ribbon flux is thought to approximate the amount of coronal magnetic flux reconnected during the event, the correlation of speeds with ribbon fluxes suggests that reconnection plays some role in accelerating CMEs. One possibility is that reconnected fields that wrap around the rising ejection produce an increased outward hoop force, thereby increasing CME acceleration. The correlation of CME speeds with more rapidly decaying overlying fields might be caused by greater downward magnetic tension in stronger overlying fields, which could act as a source of drag on rising ejections.  相似文献   

Temporal and spatial variability of sea level and volume flux in the Murderkill Estuary     

Kuo-Chuin Wong  Brian Dzwonkowski  William J. Ullman 《Estuarine, Coastal and Shelf Science》2009,84(4):440-446

The instantaneous sea level determined at two sites in the Murderkill Estuary, a tributary of Delaware Bay, results from the superposition of temporal variability operating over different time and spatial scales. Over the relatively short tidal time scales, the semidiurnal tides that represent the dominant tidal constituents in lower Delaware Bay show a modest increase in tidal amplitudes from the bay mouth (Lewes, Delaware), up to Bowers Beach (the mouth of the Murderkill Estuary). However, as the tides propagate into the Murderkill Estuary, the semidiurnal constituents undergo heavy attenuation, resulting in a 48% reduction in tidal amplitude from Bowers to Frederica (approximately the extent of saline intrusion). The diurnal tide, on the other hand, experiences only a 25% reduction in amplitude. The limited tidal asymmetry that is observed may be a result of interaction between flows in the tidal channel and the adjacent salt marsh. At longer time scales, the subtidal sea level experiences no attenuation. The Murderkill Estuary thus behaves like a low pass filter to preferentially damp out high frequency sea level forcing from lower Delaware Bay. The subtidal volume flux in the Murderkill is highly coherent with the time rate of change of sea level, indicating that the Murderkill basically co-oscillates with Delaware Bay in a standing wave fashion over the subtidal time scale. This remote coupling controls more than 90% of the variance in subtidal sea level in the estuary. The surface slopes in the lower bay and the Murderkill Estuary are closely correlated with winds along the orientation of the two waterways, consistent with the effect of local wind on subtidal sea level.  相似文献   

Ecological performance and possible origin of a ubiquitous but under-studied gastropod     

Mad S. Thomsen  Thomas Wernberg  Fernando Tuya  Brian R. Silliman 《Estuarine, Coastal and Shelf Science》2010

Invasions by non-indigenous species (NIS) have been suggested to alter local, regional and global biota on unprecedented scales. To manage NIS, it is pivotal to identify whether a species is introduced or native, but even today the geographical origin of thousands of species worldwide remain uncertain. Most of these ‘cryptogenic species’ are inconspicuous and rare, but in a few instances, they can also be abundant and conspicuous species, with large impacts on community structure. The identification of cryptogenic species, and summarizing information on their most likely origin, is an important task in invasion biology, and can highlight the need for research and management. Here, we document that the gastropod Batillaria australis in the Swan River estuary (Perth, Western Australia) is a conspicuous species of uncertain origin. A literature review combined with new survey data revealed that all evidence point to a recent human-mediated transfer; for example, it is absent from the fossil record, was first collected in 1954, has a low parasite diversity, has increased its population size dramatically in recent times, is separated by >3000 km from conspecifics, has no long-distance dispersal mechanisms, and existing ocean currents run against a natural range extension. Surprisingly, despite political and scientific focus on NIS hardly any ecological data have been published on this species from Western Australia. We show that B. australis is highly abundant in both seagrass beds (424 ± 29 ind m⁻²) and on unvegetated sand flats (92 ± 22 ind m⁻²) being orders of magnitudes more abundant than any native gastropod in the Swan River. Experiments showed that high resistance to predation and environmental stress potentially explains its success. From our survey data, we calculated that >3.6 billion invasive snails today occupy the Swan River. This large snail populations support other organisms; for example, almost 1 billion macroalgae are found attached to living B. australis and >100 million hermit crabs occupy its empty shells. Given Battilaria’s high abundance, wide distribution, large size, persistent shells that support other organisms and bioturbating behavior, it seems inescapable that this potential invader has impacted the ecosystem functioning of the Swan River. We argue that the search for abundant species of uncertain origin should continue, and that these species generally should be treated with the same interest as high status invaders to mitigate impacts in already invaded systems and to avoid secondary spread into neighboring ecosystems.  相似文献   

An unusual occurrence of coesite at the Lonar crater,India          下载免费PDF全文

Steven J. Jaret  Brian L. Phillips  David T. King Jr  Tim D. Glotch  Zia Rahman  Shawn P. Wright 《Meteoritics & planetary science》2017,52(1):147-163

Coesite has been identified within ejected blocks of shocked basalt at Lonar crater, India. This is the first report of coesite from the Lonar crater. Coesite occurs within SiO₂ glass as distinct ~30 μm spherical aggregates of “granular coesite” identifiable both with optical petrography and with micro‐Raman spectroscopy. The coesite+glass occurs only within former silica amygdules, which is also the first report of high‐pressure polymorphs forming from a shocked secondary mineral. Detailed petrography and NMR spectroscopy suggest that the coesite crystallized directly from a localized SiO₂ melt, as the result of complex interactions between the shock wave and these vesicle fillings.  相似文献   

Effects of oxidative stress on protein thiols and disulphides in Mytilus edulis revealed by proteomics: actin and protein disulphide isomerase are redox targets     

McDonagh B  Sheehan D 《Marine environmental research》2008,66(1):193-195

Many proteins contain cysteines which are sensitive to oxidation. This is sometimes reversible through interaction with glutathione, glutaredoxin or thioredoxin systems making these proteins potential sensors of oxidative stress. In this study we analysed whether there was an increase in mixed disulphide bond (-S-S-) formation in the blue mussel Mytilus edulis in response to menadione. This was achieved by initially blocking reduced thiols with N-ethylmaleimide, -S-S- were then reduced with dithiothreitol (DTT) and labelled with 5-iodoacetamidofluorescein (5-IAF). Free -SHs were also labelled directly with 5-IAF. Separations were performed on 1D or 2D SDS PAGE and images analysed. There was an increase in -S-S- in response to menadione and detection of changes in oxidised proteins was easier than that of changes in the amount of reduced proteins. Protein disulphide isomerase (PDI) was labelled both as -SH and -S-S-, underlining its involvement in the redox status of the animal. A glutathione transferase (GST P1-1) forms an inter-chain disulphide bridge in response to menadione.  相似文献