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1.
Land use conflict involving farm externalities represents an increasing policy concern in Australia as agricultural activities intensify and as the nation's metropolitan areas continue to expand outwards. A review of the rural-urban fringe literature reveals a noticeable absence of research exploring the intensity of conflict experienced by farmers. Similarly, inadequate attention has been given to the policies adopted by government to manage conflict. This article contrasts the regulatory system that has been implemented to manage conflict involving poultry farming on the metropolitan fringe of two Australian state capitals: Perth, Western Australia and Sydney, New South Wales. Spatial variation in the nature of government intervention is uncovered. In the discussion that follows reasons are identified to help explain such variation including state ideology, metropolitan growth, industry activism, geographical constraints and farm characteristics. It is concluded that where agricultural industries experience internal political divisions and a geographically dispersed membership it becomes more difficult to influence government policy.  相似文献   
2.
Tracers provide one of the few ways of obtaining realistic information on the flows of water and solutes in undisturbed structured soils. Three fluorinated organic acids [pentafluorobenzoic acid, 2,6-diflurobenzoic acid and o-(trifluoromethyl) benzoic acid] and bromide were tested as anionic tracers in situations where the separation of different flow components is of interest. The fluorobenzoates were relatively conservative (approximately 90% for loam soil) although, in some instances, co-elution or complexation may lead to apparently non-conservative behaviour. Tracer mixtures applied to soils, were separated and quantified by high-performance liquid chromatography. The relative mobilities of the tracers were studied during unidirectional steady flow in large undisturbed soil columns brought back to the laboratory. The breakthrough curves showed highly dispersive behaviour, with very early breakthrough of solute and a long tail. Contributions to the column outflow of different simultaneous applications of rainfall and return flow, labelled with different tracers, were separated using multicomponent mixing equations. The results show the importance of preferential flow and relatively immobile storage in the transport process.  相似文献   
3.
A series of experiments designed to study the separation of flow components from two large undisturbed cores under steady-state rainfall (downward) and return (upward) flows under near-saturated conditions is summarized. The experiments were conducted on soil columns collected from Lancaster University and the Slapton Wood catchment, Devon. The use of the relatively conservative tracers, potassium bromide, o-(trifluoromethyl)benzoic acid and 2,6-difluorobenzoic acid and a combination of application rates made it possible to quantify the different sources of water contributing to the discharge hydrographs. There is significant retention of tracer within the cores, despite the application of several pore volumes of water. The use of steady flow conditions allowed the determination of dispersion coefficients, dispersivity and proportion of ‘mobile’ water content parameters of the advection–dispersion equation. It was found that there were significant differences between the dispersivities at different flow-rates under upward and downward flux conditions and that in the undisturbed cores studied here the apparent proportions of mobile pore water ranged between 0.33 and 1.0, with an apparently complex relationship to flux rate. Prediction of transport in undisturbed soil remains problematic and tracer experiments will continue to be needed to provide a fundamental understanding of the complex flow processes involved.  相似文献   
4.
The Red Hill intrusion, New Hampshire is one of the alkalineintrusions making up the White Mountain Magma Series. Earlierwork has shown that it consists of several units with ring-or plug- like form, in order of intrusion: Outer Coarse Syenite(OCS) plus Nepheline Sodalite Syenite (NSS Fire Tower Sycnite(FTS); Garland Peak Syenite (GPS) Watson Ledge Quartz Syenite(WLQS) Interior Fine Granite (IFG). New studies have revealedtrends of increasing alkalinity in both the OCS (OCS-AOCS-B)and NSS (NSS-A-B-C). Conventional K-Ar and Rb-Sr age datingon separated minerals and bulk rocks show that the OCS, NSS,FTS, and GPS have indistinguishable ages at 198.5?1.5 Ma whilethe IFG formed about 10 Ma later. These values are believedto represent intrusion ages. Amphiboles from the NSS vary from ferro-pargasites through taramitesto katophontes and pyroxenes from ferrosalites to aegirine-augitesthese trends follow the increasing degree of under- saturationin the NSS-A-C series. The NSS-A contain mafic syenite xenolithsas well as partially resorbcd salitic pyroxene cores withinamphiboles. Mineral and isotope data are consistent with theseinclusions being cognate suggesting derivation from more-basicparental magmas. Pyroxenes and amphiboles from saturated andoversaturated rocks vary from ferro-salites to ferro-hedenbergitesand hastingsites to ferro-edenites, respectively, but OCS-Bshow fractionation towards aegirine-augites and katophorites. Mineral assemblages crystallized close to the quartz-fayalite-magnetitebuffer at a pressure of about 1–1.5 kb under essentiallyfluid-saturated conditions. It seems likely that the complexformed by emplacement of fractionated magmas derived from alower-level magma chamber which initially contained a basalticparent magma. The first pulse of magma had an overall compositionsimilar to OCS plus NSS and was intruded as a sheet-like bodywhich differentiated in situ to give a central unit of highlyundersaturated magma (NSS-C). NSS-C samples with relativelyradiogenic Sr isotope compositions were modified by introductionof country-rock Sr via circulating fluids. Fractional crystallizationof alkali-rich amphiboles from critically undersaturated magma(NSS-A?) in the lower- level chamber led to the developmentof saturated and oversaturated magmas. These were intruded intothe OCS/NSS unit along ring fractures to form the FTS and GPSunits. Rock and mineral compositions, including isotope data,are consistent with the IFG forming by partial melting of countryrock and being intruded along pre-existing planes of weaknesssome 10 Ma after the main complex was formed.  相似文献   
5.
1 IntroductionAtlatitudesaround 80°Nandinthemesosphere /lowerthermosphere (MLT) ,therehavebeenfewmeasurementsofneutraldynamics.ArequirementwasseenforlongtermcontinualmonitoringandaVHFmeteorradarwasidentifiedasbeingamostsuitableinstrument.RadarsliketheEISCA…  相似文献   
6.
Molybdenum disulfide (MoS2), a layered transition-metal dichalcogenide, has been of special importance to the research community of geochemistry, materials and environmental chemistry, and geotechnical engineering. Understanding the oxidation behavior and charge-transfer mechanisms in MoS2 is important to gain better insight into the degradation of this mineral in the environment. In addition, understanding the insertion of metals into molybdenite and evaluation of charge-transfer mechanism and dynamics is important to utilize these minerals in technological applications. Furthermore, a detailed investigation of thermal oxidation behavior and metal-insertion will provide a basis to further explore and model the mechanism of adsorption of metal ions onto geomedia.  相似文献   
7.
白云鄂博碳酸岩的方解石-白云石地质温度计   总被引:6,自引:2,他引:4  
利用方解石-白云石地质温度计对白云鄂博地区碳酸岩的平衡温度进行了测定。出露于东矿下盘的白云岩质火山岩和出露于尖山的方解石-白云石型火山岩获得了较高的温度,分别为681℃和648℃。这些样品中的方解石呈二十微米左右晶形较完整的小片,被稍大粒度的白云石颗粒包裹,未受交代作用影响,推测这种碳酸岩在快速冷却的情况下保存下了其岩浆侵位时的成分特点,从而指示出接近碳酸岩浆侵位时的温度。但本区多数碳酸岩的平衡温度在400~500℃之间,有下列三种情况:(1)具有自形-半自形中粗粒粒状变晶结构的碳酸岩最后的平衡温度为415~496℃;(2)产自东矿的其余样品(火山岩),所测最后平衡温度为431~485℃,在测温的微区范围内可见极细粒白云石方解石与稀土等矿物共生的现象;(3)为交代重结晶结构的碳酸岩明显受到后期热液流体的交代,在流体的作用下共生方解石和白云石在成分上达到新的平衡,平衡温度为432~507℃。本文所分析的样品多数结果(371~507℃)与用白云石(方解石)和磁铁矿氧同位素温度计对白云鄂博碳酸岩的计算结果(360~546℃)十分一致。虽然有研究者对方解石-白云石温度计用于火成碳酸岩表示过质疑,但本文资料表明火成碳酸岩最后的平衡温度是可以运用方解石-白云石温度计法来计算的。  相似文献   
8.
Most of the Quaternary sediments of the Mozambique Fan have been derived from Africa-Madagascar and deposited by turbidity currents in Pleistocene time. Currents caused by movement of the Antarctic Bottom Water also played a significant role in reworking and redepositing sediments along the marginal areas of the fan. The inner or upper Mozambique Fan is characterized by a single, leveed valley. Due to the effects of the Coriolis force, the natural levees to the east of the valley (left, looking downstream) are higher and contain more terrigenous sediments than those to the west of the valley. The sea floor to the west of the valley returns regular hyperbolic echoes as seen on 3·5 kHz echograms, whereas to the east of the valley, the sea floor is relatively smooth. The sediments on the valley floor are coarse-grained (with median grain up to 2 mm) and poorly sorted, and occur often as massive turbidites, interbedded with hemipelagic sediments. Away from the valley, both to the east and the west, the terrigenous sediments are relatively fine-grained and have been deposited as overbank turbidite sequences. We estimate the maximum velocities of the channelized turbidity currents in the upper fan to have been 8–32 ms?1. The middle fan has several distributary channels with no levees and has a relatively flat sea floor, characterized by lack of acoustic penetration. Thick, sheet-like, turbidite sand beds, deposited primarily by unchannelized turbidity currents, characterize the middle fan. The middle fan grades, towards the margins, into the outer (lower) fan which is relatively free of channels, has good acoustic penetration and contains hemipelagic and pelagic sediments, and thin, fine-sand turbidite and/or contourite beds. A wide zone of sediment waves, formed from the reworking of the turbidity current-fed sediments by the Antarctic Bottom Water, forms part of the outer fan.  相似文献   
9.
安徽巢湖凤凰山剖面石炭系微相和层序地层特征   总被引:9,自引:1,他引:9  
应用露头层序地层学基本原理和方法 ,对巢湖凤凰山石炭系剖面进行重新研究。巢湖凤凰山石炭系总厚度为79.0 2 m ,在这个剖面中可以识别出 6种主要岩相、18种微相和 11个三级沉积层序 ,其中六个三级沉积层序属于 I型沉积层序 ,三个属于 II型沉积层序 ,缺失第 9和第 10沉积层序。三级沉积层序在不同的古地理单元和不同的沉积环境中可以进行对比。根据各微相特征和成因 ,揭示了沉积间断面上存在的多期古岩溶现象。阐述了三级层序及其对应的三级海平面升降旋回的特征  相似文献   
10.
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