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51.
In this article, we used a non-radial DEA under natural and managerial disposability to measure the unified efficiency of 30 administrative regions in China and then evaluated their operational and environmental performances. We proposed the performance progress unified index (PPUI) based on the non-radial DEA methodology in a time horizon under natural and managerial disposability with a crossover to measure the performance variety of DMUs. The results of the unified efficiency measured under natural and managerial disposability showed that both operational and environmental performance in eastern China were the highest among the three regions during 2000–2011. The PPUIs under natural and managerial disposability indicated that the operational and environmental performance of the three regions improved during 2000–2011, and the rate of operational and environmental performance of eastern China was higher than the other two regions. 相似文献
52.
Abrupt climate change and early lake development – the Lateglacial diatom flora at Hässeldala Port,southeastern Sweden 下载免费PDF全文
Linda Ampel Malin E. Kylander Margret Steinthorsdottir Barbara Wohlfarth 《Boreas: An International Journal of Quaternary Research》2015,44(1):94-102
The fossil diatom record from the Hässeldala Port palaeolake, southeastern Sweden, offers an excellent opportunity to investigate how past climatic shifts influenced catchment conditions and early lake development. The record, dating to between 13 900 and 11 200 cal. a BP, covers a climatically dynamic period, starting with deglaciation followed by oscillations between warmer and colder climate states. The stratigraphical changes in the fossil diatom assemblages show a trend of less open‐water taxa and a successively more complex periphytic community as the lake shallows and the aquatic habitat structure develops. A diatom‐based reconstruction of lake water pH indicates a natural acidification trend early in the record from 13 900 to 12 500 cal. a BP. From 12 500 cal. a BP, coincident with the start of climate cooling, to 11 300 cal. a BP this trend is disrupted and lake waters become more alkaline. A cooler and drier climate most likely resulted in reduced soil organic matter build‐up as well as more frozen ground that impeded hydrological flow and decreased the input of dissolved organic matter and organic acids into the lake system. This study demonstrates the importance of the hydrological system as a link between terrestrial and aquatic ecosystems during early lake ontogeny. 相似文献
53.
54.
Malin Andersson Rolf Tore Ottesen Morten Jartun Ola Eggen Ann-Christine Enqvist 《Applied Geochemistry》2012
Work reported in this paper suggests that there are cases of contamination of soil and water samples by polychlorinated biphenyls (PCB) from paper and plastic packaging. Soil samples, which have been stored in paper bags for more than 20 years, share a similar congener distribution as the bags. Analyses showed a predominance of light congeners. PCB-analyses of water also indicate that water samples could be contaminated by plastic packaging. All analytical results of solid material packaging, as well as soil stored in the packaging, show a high relative amount of light weight PCB congeners. The paper bags that were analysed are made of strong paper and very popular among geochemists because of their watertight quality. These paper bags were manufactured more than 20 years ago. The plastic packaging that was analysed was produced in 1997 and 2008. The analyses of plastic and paper show that the raw material that has been used in the production at different times contains a wide concentration range of PCB. Re-sealable plastic bags, which contained the highest levels of PCB of the plastic material, are used by researchers world-wide as sampling bags for soils and sediments. This paper raises an important issue that packaging may potentially contaminate the samples that they hold. 相似文献
55.
R. F. Minchin M. J. Disney Q. A. Parker P. J. Boyce W. J. G. de Blok G. D. Banks † R. D. Ekers K. C. Freeman D. A. Garcia B. K. Gibson M. Grossi R. F. Haynes P. M. Knezek R. H. Lang D. F. Malin R. M. Price M. Putman I. M. Stewart A. E. Wright 《Monthly notices of the Royal Astronomical Society》2004,355(4):1303-1314
56.
Loic Piret Sebastien Bertrand Jon Hawkings Malin E. Kylander Fernando Torrejón Benjamin Amann Jemma Wadham 《地球表面变化过程与地形》2021,46(1):239-251
Proglacial lakes are effective sediment traps but their impact on the reliability of downstream sediment records to reconstruct glacier variability remains unclear. Here, we investigate the sedimentary signature of the recent recession of Steffen Glacier (Chilean Patagonia, 47°S) in downstream fjord sediments, with a focus on identifying the trapping (decreased downstream sediment yield) and filtering (removal of coarse particles) effectiveness of a growing intermediate proglacial lake. Four sediment cores were collected along a 14 km longitudinal transect in Steffen Fjord and the sediment physical and chemical properties were compared with aerial imagery at high temporal resolution. The caesium-137 (137Cs) chronology of the most distal core and sediment trap data suggest that sediment accumulation in the fjord remained relatively stable through time, despite the accelerating glacier recession and the growth of Steffen proglacial lake. This is in contrast with many studies that indicate a decrease in sediment yield during proglacial lake expansion. It implies that the increase in sediment export due to accelerating meltwater production may be balanced by the sediment trapping effect of the growing proglacial lake. The fjord sediments show a slight fining upward accompanied by a marked decrease in flood-induced grain-size peaks, most likely due to the increasing filtering and dampening effect of the expanding proglacial lake. Our findings show that the filtering effect of the proglacial lake reached a threshold in 1985, when the lake attained an area of 2.02 km2. The additional 5 km of glacier recession during the following 32 years did not have any significant impact on downstream sedimentation. This study confirms that proglacial lakes act as sediment traps but it indicates that (1) the trapping effect can be outpaced by accelerating glacier recession and (2) the filtering effect becomes stable once the lake attains a certain critical size. © 2020 John Wiley & Sons, Ltd. 相似文献
57.
小样本数据下安徽省经济-环境系统协调发展的实证分析 总被引:1,自引:0,他引:1
作为一个非线性复杂系统,经济与环境之间相互作用,两者之间如果彼此协调,就能推动社会的可持续发展,反之则会阻碍社会的发展,中国各省份情况概莫能外。使用主成分分析和环境与经济系统协调度计量模型,对安徽省2000-2010 年的经济—环境协调状况进行了定量分析,计算出该省经济—环境之间的协调度;然后利用基于IOWA算子的组合预测方法,对小样本数据进行外推预测;进而给出"十二五"期间实现安徽省经济—环境系统协调发展的政策建议,指出当地政府在制定相应公共政策时,应对本地区经济—环境系统影响较大的因子予以格外关注,同时要避免地区之间争夺区域外投资的恶性竞争,否则将不利于经济—环境系统的协调发展。 相似文献
58.
Barbara Wohlfarth Francesco Muschitiello Sarah L. Greenwood August Andersson Malin Kylander Rienk H. Smittenberg Margret Steinthorsdottir Jenny Watson Nicola J. Whitehouse 《Boreas: An International Journal of Quaternary Research》2017,46(2):143-161
The Last Termination (19 000–11 000 a BP) with its rapid and distinct climate shifts provides a perfect laboratory to study the nature and regional impact of climate variability. The sedimentary succession from the ancient lake at Hässeldala Port in southern Sweden with its distinct Lateglacial/early Holocene stratigraphy (>14.1–9.5 cal. ka BP) is one of the few chronologically well‐constrained, multi‐proxy sites in Europe that capture a variety of local and regional climatic and environmental signals. Here we present Hässeldala's multi‐proxy records (lithology, geochemistry, pollen, diatoms, chironomids, biomarkers, hydrogen isotopes) in a refined age model and place the observed changes in lake status, catchment vegetation, summer temperatures and hydroclimate in a wider regional context. Reconstructed mean July temperatures increased between c. 14.1 and c. 13.1 cal. ka BP and subsequently declined. This latter cooling coincided with drier hydroclimatic conditions that were probably associated with a freshening of the Nordic Seas and started a few hundred years before the onset of Greenland Stadial 1 (c. 12.9 cal. ka BP). Our proxies suggest a further shift towards colder and drier conditions as late as c. 12.7 cal. ka BP, which was followed by the establishment of a stadial climate regime (c. 12.5–11.8 cal. ka BP). The onset of warmer and wetter conditions preceded the Holocene warming over Greenland by c. 200 years. Hässeldala's proxies thus highlight the complexity of environmental and hydrological responses across abrupt climate transitions in northern Europe. 相似文献
59.
While previous research has documented marine fish and invertebrates shifting poleward in response to warming climates, less is known about the response of fisheries to these changes. By examining fisheries in the northeastern United States over the last four decades of warming temperatures, we show that northward shifts in species distributions were matched by corresponding northward shifts in fisheries. The proportion of warm-water species caught in most states also increased through time. Most importantly, however, fisheries shifted only 10–30 % as much as their target species, and evidence suggested that economic and regulatory constraints played important roles in creating these lags. These lags may lead to overfishing and population declines if not accounted for in fisheries management and climate adaptation. In coupled natural-human systems such as fisheries, human actions play important roles in determining the sustainability of the system and, therefore, future conservation and climate mitigation planning will need to consider not only biophysical changes, but also human responses to these changes and the feedbacks that these responses have on ecosystems. 相似文献
60.
Graeme L. White David L. Jauncey Bruce R. Harvey Ann Savage Samuel Gulkis Robert A. Preston Bruce A. Peterson John E. Reynolds George D. Nicolson D. F. Malin 《Astrophysics and Space Science》1991,177(1-2):79-83
An overview is presented of a number of astrometry and astrophysics programs based on radio sources from the Parkes 2.7 GHz catalogues. The programs cover the optical identification and spectroscopy of flat-spectrum Parkes sources and the determination of their milliarc-second radio structures and positions. Work is also in progress to tie together the radio and Hipparcos positional reference frames. A parallel program of radio and optical astrometry of southern radio stars is also under way. 相似文献