Regional and local variations in the emerging economic landscape of the new German Länder     

Philip N. Jones  Trevor Wild 《Applied geography (Sevenoaks, England)》1997,17(4):283-299

Events in eastern Germany since 1989 pose major challenges for geographical interpretation. This paper examines the spatial impacts of the post-unification economic and social upheavals in the new Länder. Using unemployment rates as a key indicator of regional differentiation, spatial variability within the new Länder is examined in terms of two fundamental dimensions. First, the relationship with former patterns of economic specialization is explored, and secondly, the effects of basic geographical properties such as settlement structure, location and peripherality. Prominent regional polarities are described, notably between major agglomeration cores and rural residuals, and between ‘bridgehead’ locations and less-accessible districts. Within this context the paper then identifies some ‘green shoots’ of recovery and new growth. It concludes by emphasizing the importance of incorporating sub-regional variations into any new framework of regional policy.  相似文献   

Determining the climatic requirements of trees suitable for agroforestry     

Trevor H. Booth 《Climatic change》1994,27(1):93-102

After fossil fuel burning, clearing of forests for agriculture is the second most significant factor increasing levels of atmospheric carbon dioxide. Replanting trees on previously cleared land around the world could reduce the buildup of atmospheric carbon dioxide. However, forests were usually cleared to grow crops or graze animals, so there is no possibility of completely restoring forests on most cleared lands. There is a need to develop agroforestry systems, which integrate trees with agricultural activities.One of the key problems in developing successful agroforestry systems is identifying which trees can be successfully grown in different areas. This problem will become even greater as tree breeding produces a wider variety of genotypes available for planting. General methods are described to identify where a particular tree (species, provenance or clone) with potential for use in agroforestry systems can be grown. The methods also help to identify locations where particular trees are growing under relatively extreme climatic conditions for that taxa. Conditions at these locations should be carefully evaluated as more reliable future climatic scenarios are developed. In the meantime they could be monitored to provide early warning of the effects of climatic and atmospheric change.  相似文献   

River system discontinuities due to lateral inputs: generic styles and controls     

Robert I. Ferguson  Judith R. Cudden  Trevor B. Hoey  Stephen P. Rice 《地球表面变化过程与地形》2006,31(9):1149-1166

In alluvial river systems, lateral inputs of water and/or sediment at junctions or undercut hillsides can disrupt what would otherwise be smooth downstream trends in mainstream bed elevation, channel gradient, and bed grain size. Generic styles of mainstream response to lateral inputs are investigated using a one‐dimensional sediment routing model with multiple grain size fractions. Numerical experiments isolate the effects of three para‐meters: ratio of tributary to mainstream water flux (QR), ratio of tributary to mainstream bedload flux (FR), and ratio of tributary to mainstream bedload diameter (DR). The findings are not unduly sensitive to the choice of initial conditions or to approximations made in the model. The primary distinction is between junctions that aggrade, causing local profile convexity with interrupted downstream fining, and junctions that degrade. The immediate effects of aggradation extend further upstream than downstream, whereas degradation is much more subdued and has no upstream impact. Aggradation is typical of coarse inputs (DR > 2), and degradation of fine inputs (DR < 1), but very high ratios of QR to FR also promote degradation. Both aggrading and degrading junctions can lead to a change in mainstream bed grain size well below the junction, with higher ratios of QR to FR producing a coarser distal bed. The effect of a tributary reflects the interplay between additional bed load and additional discharge to transport it. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

Malaysia, Modernity and the Multimedia Super Corridor: A Critical Geography of Intelligent Landscapes – Edited by Tim Bunnell     

Trevor Hogan 《Singapore journal of tropical geography》2007,28(1):112-113

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Mercury distribution and transport in a contaminated river system in Kazakhstan and associated impacts on aquatic biota   总被引：1，自引：0，他引：1  

Susanne M. Ullrich  Mikhail A. Ilyushchenko  Grigory A. Uskov  Trevor W. Tanton 《Applied Geochemistry》2007,22(12):2706

The River Nura in Central Kazakhstan has been heavily polluted by Hg originating from an acetaldehyde plant. A number of studies were undertaken to investigate the transport, fate and bioavailability of Hg in this river system. The sediments within a 20 km section of the river downstream of the effluent outfall canal are highly polluted and are acting as a strong source of surface water contamination. Mercury transport in the river is dominated by the remobilization of contaminated bed sediments and river bank erosion during the annual spring flood. Peak Hg concentrations in unfiltered surface water samples during a larger than usual flood event in 2004 were in the order of 1600–4300 ng L⁻¹. The majority of the particulate-bound Hg appears to be sedimented in the shallow Intumak reservoir 75 km downstream of the source of the pollution, leading to a drop in aqueous Hg concentrations by an order of magnitude. Nevertheless, background concentrations of Hg in surface water are not reached until at least 200 km downstream, and during the flood period Hg is also detected in the terminal wetlands of the river.Mercury concentrations in sediment cores taken from the river bed in the most contaminated section of the Nura ranged from 9.95 to 306 mg kg⁻¹. Methylmercury (MeHg) levels in shallow sediment cores were highest in surface sediments and ranged between 4.9 and 39 μg kg⁻¹, but were generally less than 0.1% of total Hg (THg). A significant inverse relationship was found between THg concentrations and the percentage of MeHg formed in the sediments, irrespective of the sampling depth. The observed relationship was confirmed by comparison with results from a different river system, indicating that it may be true also for other highly contaminated aquatic systems. It is hypothesized that at high THg levels in severely contaminated sediments, the accumulation of MeHg may be limited by increasingly efficient demethylation processes, and that this underlying trend in sediments is the reason why MeHg levels in surface water are often found to be higher at less contaminated sites compared to upstream sites.Mercury concentrations in biota in the most contaminated section of the river were 15–20 times higher than background levels. Fish were found to be impacted for more than 125 km downstream from the source, indicating significant transport of dissolved MeHg to downstream areas and/or in-situ MeHg production in less contaminated downstream reaches. There were also indications that impoundments may increase the bioavailability of Hg.  相似文献   

Major Miocene geological events in southern Tibet and eastern Asia induced by the subduction of the Ninetyeast Ridge     

Xinlei Sun  Wei-dong Sun  Yong-bin Hu  Wei Ding  Trevor Ireland  Mei-zhen Zhan  Ji-qiang Liu  Ming-xing Ling  Xing Ding  Zhao-feng Zhang  Wei-ming Fan 《中国地球化学学报》2018,37(3):395-401

Cenozoic adakitic rocks in the Gangdese changed from barren continental melts to ore-forming slab melts at ~ 23 Ma. The distribution and chemical characteristics of the ore-forming adakites point to an association with the Ninetyeast Ridge. The subduction of the thick, rigid Ninetyeast Ridge changed the geometry and rheology of the eastern Tibetan Plateau lithosphere and asthenosphere, restrained the eastward escape of asthenospheric mantle as well as continental fragments, and promoted the uplift and building of the Tibetan Plateau, which consequently changed the tectonic and climatic regimes in eastern Asia.  相似文献   

Partial substitution of peat moss with biochar for sustainable cultivation of <Emphasis Type="Italic">Durio zibethinus L</Emphasis>. in nurseries     

Robert Thomas Bachmann  Sharifah Adawiyah  Thilagam Krishnan  Benson Khoo  Tan Sue Sian  Trevor Richards 《Arabian Journal of Geosciences》2018,11(15):426

The extensive use of peat moss as potting medium in nurseries worldwide is not sustainable causing peatland depletion and greenhouse gas emissions. This research seeks to explore whether wood biochar produced by the environment-friendly flame curtain method can partially substitute peat moss in plant nurseries without affecting plant growth and health. Biochar was produced from durian wood logs in a top-quenched Kon-Tiki earth kiln, crushed, and mixed with peat moss at dosages of 0, 1, 2.5 and 5% (w/w). Durian seedlings were grown in 2.5 L polybags arranged in randomised complete block design with 4 replicates per treatment. Plant height, collar diameter, pH, moisture content, number of branches and leaves, and plant health were monitored weekly for 94 days. Liquid fish fertiliser was used as organic fertiliser. Our results demonstrated that biochar can substitute at least 5% (w/w) peat moss without negatively affecting plant height, collar diameter, number of leaves and branches, and plant health. In addition, organic fertiliser is not required during the first 3 months of cultivation resulting in cost savings to the nursery operator. Plant height was found to be the most accurate yet simple monitoring parameter studied. A better understanding of the effect of higher biochar application rates as well as the number of times the potting medium can be reused without loss of potting medium properties and health can help to further cut nursery cost and reduce reliance on peat moss.  相似文献   

Zircon U–Pb,O, and Hf isotopic constraints on Mesozoic magmatism in the Cyclades,Aegean Sea,Greece     

Bin Fu  Michael Bröcker  Trevor Ireland  Peter Holden  Leslie P. J. Kinsley 《International Journal of Earth Sciences》2015,104(1):75-87

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Scaling relations in early-type galaxies belonging to groups     

Habib G. Khosroshahi  Somak Raychaudhury  Trevor J. Ponman  Trevor A. Miles  Duncan A. Forbes 《Monthly notices of the Royal Astronomical Society》2004,349(2):527-534

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Modeling the Usefulness of Spatial Correlation Analysis on Karst Systems     

by Trevor J. Budge  and John M. Sharp Jr. 《Ground water》2009,47(3):427-437

Cross-correlation analyses on field data collected in karst aquifer systems can be used to develop a conceptual understanding of the aquifer. This includes the use of many data sets from the same aquifer to develop an understanding of how properties vary spatially. We focus on a method for characterizing the distribution of recharge, which is becoming increasingly important in regions where urban development encroaches on these important sources of water. Spatially varying precipitation data and cross-correlation analysis provide a means of spatially characterizing recharge locations on a karst aquifer. Our work expands on the numerical experiments conducted by Padilla and Pulido-Bosch (1995) using the numerical ground water model MODFLOW to introduce spatially varying parameters. The numerical experiments include conduit-controlled, matrix-controlled, and mixed karst systems with more than one precipitation time series input. The results show that spatially varying parameters can be inferred based on the cross-correlation of precipitation data and spring discharge. Simulations were completed using aquifer parameters derived from studies of the Barton Springs segment of the Edwards Aquifer. The simulations indicate that spatial variability within an aquifer can be inferred using cross-correlation analysis. A field study using these methods is summarized for Barton Springs near Austin, Texas.  相似文献