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141.
142.
Aristides?MoustakasEmail author Matthew?R.?Evans 《Stochastic Environmental Research and Risk Assessment (SERRA)》2017,31(2):315-328
Bovine tuberculosis (TB) poses a serious threat for agricultural industry in several countries, it involves potential interactions between wildlife and cattle and creates societal problems in terms of human-wildlife conflict. This study addresses connectedness network analysis, the spatial, and temporal dynamics of TB between cattle in farms and the European badger (Meles meles) using a large dataset generated by a calibrated agent based model. Results showed that infected network connectedness was lower in badgers than in cattle. The contribution of an infected individual to the mean distance of disease spread over time was considerably lower for badger than cattle; badgers mainly spread the disease locally while cattle infected both locally and across longer distances. The majority of badger-induced infections occurred when individual badgers leave their home sett, and this was positively correlated with badger population growth rates. Point pattern analysis indicated aggregation in the spatial pattern of TB prevalence in badger setts across all scales. The spatial distribution of farms that were not TB free was aggregated at different scales than the spatial distribution of infected badgers and became random at larger scales. The spatial cross correlation between infected badger setts and infected farms revealed that generally infected setts and farms do not coexist except at few scales. Temporal autocorrelation detected a two year infection cycle for badgers, while there was both within the year and longer cycles for infected cattle. Temporal cross correlation indicated that infection cycles in badgers and cattle are negatively correlated. The implications of these results for understanding the dynamics of the disease are discussed. 相似文献
143.
Michael J. Hollaway Keith J. Beven Clare Mc W. H. Benskin Adrian L. Collins Robert Evans Peter D. Falloon Kirsty J. Forber Kevin M. Hiscock Ron Kahana Christopher J. A. Macleod Mary C. Ockenden Martha L. Villamizar Catherine Wearing Paul J. A. Withers Jian G. Zhou Nicholas J. Barber Philip M. Haygarth 《水文研究》2018,32(17):2779-2787
River discharge and nutrient measurements are subject to aleatory and epistemic uncertainties. In this study, we present a novel method for estimating these uncertainties in colocated discharge and phosphorus (P) measurements. The “voting point”‐based method constrains the derived stage‐discharge rating curve both on the fit to available gaugings and to the catchment water balance. This helps reduce the uncertainty beyond the range of available gaugings and during out of bank situations. In the example presented here, for the top 5% of flows, uncertainties are shown to be 139% using a traditional power law fit, compared with 40% when using our updated “voting point” method. Furthermore, the method is extended to in situ and lab analysed nutrient concentration data pairings, with lower uncertainties (81%) shown for high concentrations (top 5%) than when a traditional regression is applied (102%). Overall, for both discharge and nutrient data, the method presented goes some way to accounting for epistemic uncertainties associated with nonstationary physical characteristics of the monitoring site. 相似文献
144.
Zhao XinMiao Wang Hui Li ZhiHan Liu FengLin Evans Noreen J. Zhang HongFu 《Mineralogy and Petrology》2020,114(2):141-159
Mineralogy and Petrology - A detailed study on petrology and mineral chemistry of 12 mantle xenoliths from Late Cretaceous basaltic lava flows at Daxizhuang has been conducted to constrain the... 相似文献
145.
Geomorphological controls and catchment sediment characteristics control the formation of floodplains and affect their capacity to sequester carbon. Organic carbon stored in floodplains is typically a product of pedogenic development between periods of mineral sediment deposition. However, in organically-dominated upland catchments with a high sediment load, eroded particulate organics may also be fluvially deposited with potential for storage and/or oxidation. Understanding the redistribution of terrestrial carbon laterally, beyond the bounds of river channels is important, especially in eroding peatland systems where fluvial particulate organic carbon exports are often assumed to be oxidised. Floodplains have the potential to be both carbon cycling hotspots and areas of sequestration. Understanding of the interaction of carbon cycling and the sediment cascade through floodplain systems is limited. This paper examines the formation of highly organic floodplains downstream of heavily eroded peatlands in the Peak District, UK. Reconstruction of the history of the floodplains suggests that they have formed in response to periods of erosion of organic soils upstream. We present a novel approach to calculating a carbon stock within a floodplain, using XRF and radiograph data recorded during Itrax core scanning of sediment cores. This carbon stock is extrapolated to the catchment scale, to assess the importance of these floodplains in the storage and cycling of organic carbon in this area. The carbon stock estimate for the floodplains across the contributing catchments is between 3482-13460 tonnes, equating on an annualised basis to 0.8-4.5% of the modern-day POC flux. Radiocarbon analyses of bulk organic matter in floodplain sediments revealed that a substantial proportion of organic carbon was associated with re-deposited peat and has been used as a tool for organic matter source determination. The average age of these samples (3010 years BP) is substantially older than Infrared Stimulated Luminesence dating which demonstrated that the floodplains formed between 430 and 1060 years ago. Our data suggest that floodplains are an integral part of eroding peatland systems, acting as both significant stores of aged and eroded organic carbon and as hotspots of carbon turnover. © 2019 The Authors. Earth Surface Processes and Landforms published by John Wiley & Sons Ltd. 相似文献
146.
Controls on the location,morphology and evolution of complex esker systems at decadal timescales,Breiðamerkurjökull,southeast Iceland
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Robert D. Storrar David J. A. Evans Chris R. Stokes Marek Ewertowski 《地球表面变化过程与地形》2015,40(11):1421-1438
This paper uses detailed mapping of eskers to address three questions which are important for reconstructing meltwater behaviour beneath contemporary and ancient ice masses: ‘What controls the morphology of simple and complex esker systems?’, ‘How do esker systems evolve through time?’ and ‘Are esker patterns compatible with groundwater controlled hydraulic spacing of esker tunnels?’. Esker crestlines and widths are mapped on the Breiðamerkurjökull foreland for eight time slices between 1945 and 2007, from high resolution (~50 cm) aerial photography, permitting their long‐term morphological evolution to be analysed in a high level of detail. We find that complex eskers develop where meltwater and sediment is abundant, such that sediment clogs channels, forming distributary eskers. Isolated eskers are simpler and smaller and reflect less abundant meltwater and sediment, which is unable to clog channels. Eskers may take several decades to emerge from outwash deposits containing buried ice and can increase or decrease in size when ice surrounding and underlying them melts out. It has been suggested that groundwater–channel coupling dictates the spacing between eskers at Breiðamerkurjökull. Our results do not dispute this, but suggest that the routing of sediment and meltwater through medial moraines is an additional important control on esker location and spacing. These results may be used to better understand the processes surrounding esker formation in a variety of geographical settings, enabling a more detailed understanding of the operation of meltwater drainage systems in sub‐marginal zones beneath glaciers and ice sheets. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
147.
Toni Veikkolainen Lauri J. Pesonen David A. D. Evans 《Studia Geophysica et Geodaetica》2014,58(3):425-441
Most paleomagnetic applications require a precise, rationally organized and up-todate catalogue or database of paleomagnetic results worldwide. These include reconstructions of continents, calculations of the Apparent Polar Wander Paths (APWPs) or paleolatitude drift curves, testing the Geocentric Axial Dipole (GAD) model, studies of geomagnetic paleosecular variation or reversal asymmetries, comparison of coeval results obtained from different types of rocks, estimation of inclination shallowing in sedimentary rocks and understanding the delay in remanence acquisition caused by slow cooling in large intrusions. For this purpose, various databases, such as the Global Paleomagnetic Database (GPMDB), and the Magnetics Information Consortium Database (MagIC) have been generated. This paper presents a new relational database (PALEOMAGIA) where 3278 entries of Precambrian data have been split geographically, sorted according to age and rock types and ranked using a revised version of the Van der Voo grading scheme. The latest geochronologic information is included wherever available. Significant effort has been put to the retrieval and archiving of data published in the last decade, which are virtually nonexistent in GPMDB. Here we present the database and its browser-based user interface from a scientific and a technical point of view. 相似文献
148.
依据南海低纬地区SA09-040孔高分辨率的孢粉记录,自下至上划分了4个孢粉组合带。从孢粉成分的变化,重建了22.25ka B P以来的植被与气候变化历史。结果表明:孢粉主要来源于婆罗洲和周围岛屿,孢粉1带(22.25~16.6ka B P),低山雨林植被发育,为暖热气候,从测年时间看,当时为末次冰期晚期。孢粉2带(16.6~10.82ka B P,为末次冰消期),植被以热带低山雨林和低地雨林为主,针叶的松数量较多,当时的气温比现在低。孢粉3带(全新世早期,10.82~6.43ka B P),植被以热带低山雨林和低地雨林为主,针叶松属数量减少,气温比前期升高,海平面也上升。孢粉4带(全新世中晚期,6.43ka B P至今),全新世中期为炎热、湿润的气候环境,全新世晚期可能与婆罗洲现今的植被景观相近,为热、湿的气候环境。 相似文献
149.
150.
A vertical profile of maximum horizontal principal stress, SHmax, orientation to 5 km depth was obtained beneath the Swiss
city of Basel from observations of wellbore failure derived from ultrasonic televiewer images obtained in two 1 km distant
near-vertical boreholes: a 2755 m exploration well (OT2) imaged from 2550 m to 2753 m across the granitic basement-sediment
interface at 2649 m; and a 5 km deep borehole (BS1) imaged entirely within the granite from 2569 m to 4992 m. Stress-related
wellbore failure in the form of breakouts or drilling-induced tension fractures (DITFs) occurs throughout the depth range
of the logs with breakouts predominant. Within the granite, DITFs are intermittently present, and breakouts more or less continuously
present over all but the uppermost 100 m where they are sparse. The mean SHmax orientations from DITFs is 151 ± 13° whereas
breakouts yield 143 ± 14°, the combined value weighted for frequency of occurrence being N144°E ± 14°. No marked depth dependence
in mean SHmax orientation averaged over several hundred meters depth intervals is evident. This mean SHmax orientation for
the granite is consistent with the results of the inversion of populations of focal mechanism solutions of earthquakes occurring
between depths of 10–15 km within regions immediately to the north and south of Basel, and with the T-axis of events occurring
within the reservoir (Deichmann and Ernst, this volume). DITFs and breakouts identified in OT2 above and below the sediment-basement
interface suggest that a change in SHmax orientation to N115°E ± 12° within the Rotliegendes sandstone occurs near its interface
with the basement. The origin of the 20–30° change is uncertain, as is its lateral extent. The logs do not extend higher than
80 m above the interface, and so the data do not define whether a further change in stress orientation occurs at the evaporites.
Near-surface measurements taken within 50 km of Basel suggest a mean orientation of N–S, albeit with large variability, as
do the orientation of hydrofractures at depths up to 850 m within and above the evaporite layers and an active salt diapir,
also within 50 km of Basel. Thus, the available evidence supports the notion that the orientation of SHmax above the evaporites
is on average more N–S oriented and thus differs from the NW–SE inferred for the basement from the BS1/OS2 wellbore failure
data and the earthquake data. Changes in stress orientation with depth can have significant practical consequences for the
development of an EGS reservoir, and serve to emphasise the importance of obtaining estimates from within the target rock
mass. 相似文献