Endemic avifaunal biodiversity and tropical forest loss in Makira, a mountainous Pacific island

Anthropogenic habitat changes and the introduction of pigs, dogs, cats and rats have caused a catastrophic decline in the terrestrial biodiversity of Pacific archipelagos. At present, economic globalization and an increased demand for timber are promoting industrial logging and plantation expansion. Commercial logging can be sustainable but in practice it more often leads to land degradation, especially on small flat islands. On large and mountainous islands, however, more modest impacts can be expected as the narrowly endemic species tend to inhabit montane forests where logging is difficult. In this study we use ornithological data collected at different elevations to assess the extent to which the avifauna of Makira, a large mountainous island in Melanesia, will be affected by deforestation of the lowlands, most of which are under timber concessions. Our data suggest that a majority of the endemic bird species use lowland forest to some extent and that this may even apply to species hitherto associated with montane forest. If current commercial forestry programmes are continued, the forest habitat may be disturbed or lost over large parts of Makira, potentially undermining the natural resource base for the local subsistence economy, exacerbating climate change and threatening the integrity of one of the most important areas for biodiversity conservation on earth. Our study highlights the importance of understanding the habitat requirements of endemic species and the urgency of establishing and effectively managing community-based protected areas in suitable lowland forests of the Pacific.     

Anthropogenic impacts recorded in recent sediments from Otisco Lake,New York,USA

Geochemical analysis of ²¹⁰Pb-dated sediment cores from Otisco Lake (New York) combined with analysis of recent land cover change in the watershed revealed the history of land use change, lake management, and industrial pollution since European settlement in the northeastern US. Clearance of forestland for agriculture characterized the early settlement era that was marked in the Otisco Lake sediments by a decline in organic carbon (OC) and OC:N ratios, which indicate a change in the sources of organic matter to the lake. Agricultural land use reached its greatest areal extent in the Otisco watershed around 1900, followed by field abandonment and reforestation over the last century. In the 1920s sediment accumulation rates began to increase coincident with residential development along the lake shore. Nitrogen and organic carbon, which are transported from the watershed, show increased fluxes to the lake in response to this change. Deposition of inorganic carbon increased markedly over a short period from the 1940s to the 1980s, which is consistent with enhanced mobilization of watershed calcium by increased acidic deposition, followed by alkalinization of the lake waters and calcite precipitation. An increase in copper content in the sediments reflects application, since 1942, of the algicide copper sulfate to the lake waters to control algal blooms. This CuSO₄ marker confirmed the accuracy of the ²¹⁰Pb chronology. Atmospheric mercury (Hg) fluxes to the lake were affected by increased sediment transport from the watershed. The maximum Hg peak in the sediment record, however, was dated to the early 1970s and coincides with maximum Hg emissions to the atmosphere in the Great Lakes region.     

Modelling of fluid–solid interactions using an adaptive mesh fluid model coupled with a combined finite–discrete element model

Fluid–structure interactions are modelled by coupling the finite element fluid/ocean model ‘Fluidity-ICOM’ with a combined finite–discrete element solid model ‘Y3D’. Because separate meshes are used for the fluids and solids, the present method is flexible in terms of discretisation schemes used for each material. Also, it can tackle multiple solids impacting on one another, without having ill-posed problems in the resolution of the fluid’s equations. Importantly, the proposed approach ensures that Newton’s third law is satisfied at the discrete level. This is done by first computing the action–reaction force on a supermesh, i.e. a function superspace of the fluid and solid meshes, and then projecting it to both meshes to use it as a source term in the fluid and solid equations. This paper demonstrates the properties of spatial conservation and accuracy of the method for a sphere immersed in a fluid, with prescribed fluid and solid velocities. While spatial conservation is shown to be independent of the mesh resolutions, accuracy requires fine resolutions in both fluid and solid meshes. It is further highlighted that unstructured meshes adapted to the solid concentration field reduce the numerical errors, in comparison with uniformly structured meshes with the same number of elements. The method is verified on flow past a falling sphere. Its potential for ocean applications is further shown through the simulation of vortex-induced vibrations of two cylinders and the flow past two flexible fibres.     

Enhancing the Sustainability of Household Fe0/Sand Filters by Using Bimetallics and MnO2

Filtration systems containing metallic iron as reactive medium (Fe⁰ beds) have been intensively used for water treatment during the last two decades. The sustainability of Fe⁰ beds is severely confined by two major factors: (i) reactivity loss as result of the formation of an oxide scale on Fe⁰ and (ii) permeability loss due to pore filling by generated iron corrosion products. Both factors are inherent to iron corrosion at pH > 4.5 and are common during the lifespan of a Fe⁰ bed. It is of great practical significance to improve the performance of Fe⁰ beds by properly addressing these key factors. Recent studies have shown that both reactivity loss and permeability loss could be addressed by mixing Fe⁰ and inert materials. For a non‐porous additive like quartz, the threshold value for the Fe⁰ volumetric proportion is 51%. Using the Fe⁰/quartz system as reference, this study theoretically discusses the possibility of (i) replacing Fe⁰ by bimetallic systems (e.g., Fe⁰/Cu⁰), or (ii) partially replacing quartz by a reactive metal oxide (MnO₂ or TiO₂) to improve the efficiency of Fe⁰ beds. Results confirmed the suitability of both tools for sustaining Fe⁰ bed performance. It is shown that using a Fe⁰:MnO₂ system with the volumetric proportion 51:49 will yield a filter with 40% residual porosity at Fe⁰ depletion (MnO₂ porosity 62%). This study improves Fe⁰ bed design and can be considered as a basis for further refinement and detailed research for efficient Fe⁰ filters.     

Knowing our own history? Geography department archives in the UK

The paper presents an analysis of the returns to a questionnaire survey on the state of department archives within UK departments of geography. The results of the survey are discussed in relation to recent work in geography which has examined the archive as a site for knowledge's making but seldom in its own terms as a resource for the history of geography, and studies within the archival sciences which have considered the archive as something more than a 'storehouse' for collective memory. The paper reveals that the archival record for the history of British geography is at best uneven, and in many departments non-existent, although information on departmental history is held, often as memory, by individual geographers. The paper considers the survey's implications for the future histories of British geography and addresses the nature of the UK geography department archive as resource and responsibility.     

Groundwater remediation: the next 30 years

Groundwater remediation technologies are designed, installed, and operated based on the conceptual models of contaminant hydrogeology that are accepted at that time. However, conceptual models of remediation can change as new research, new technologies, and new performance data become available. Over the past few years, results from multiple-site remediation performance studies have shown that achieving drinking water standards (i.e., Maximum Contaminant Levels, MCLs) at contaminated groundwater sites is very difficult. Recent groundwater research has shown that the process of matrix diffusion is one key constraint. New developments, such as mass discharge, orders of magnitude (OoMs), and SMART objectives are now being discussed more frequently by the groundwater remediation community. In this paper, the authors provide their perspectives on the existing "reach MCLs" approach that has historically guided groundwater remediation projects, and advocate a new approach built around the concepts of OoMs and mass discharge.     

半无限平面问题的相对位移

通过Flamant和Melan的解析解答、Mindlin解答的积分蜕化公式以及有限元数值分析计算结果,展示了在半无限平面问题中线荷载作用方向位移解答的不确定性。线荷载作用方向没有绝对位移,只有相对位移,但相对位移会随着与位移约束参考点距离的增大而增大,或随着线荷载在垂直于半平面方向分布长度的增大而增大,不具收敛性。这意味着,在解析和数值分析中,纯粹的半平面问题的位移解答具有多值性,因此,将岩土工程问题作为半空间问题进行分析是必要的。     

Proposed design models for the asymmetric friction connection

The Asymmetric Friction Connection (AFC) remains elastic during moderate earthquake shaking but slides and dissipates energy through friction during severe earthquake shaking. The sliding friction forces developed are dependent on the clamping force in the connection which is provided by fully tensioned bolts which pass through slotted holes. During sliding these bolts are subject to moment and shear as well as axial force. Moment–shear–axial force interaction reduces the clamping axial force on the sliding interfaces thereby reducing the sliding shear resistance (V_ss). Two methods to evaluate the moment–shear–axial force interaction have been proposed so that the sliding shear strength can be quantified, but as yet, these methods are not robust. This paper describes the results of 60 tests undertaken to improve the two methods, namely the moment–shear–axial force bolt model and the effective coefficient of friction method, for AFCs with high hardness steel shims. The bolts were M16 to M30 bolts and cleat thicknesses ranged from 12 mm to 25 mm. It is shown that either method may be used in design as the results obtained are similar. Copyright © 2014 John Wiley & Sons, Ltd.     

地质观测、地震剖面和重力测量的综合方法在前陆褶皱冲断带的应用：以天山北麓呼图壁河剖面为例

褶皱逆冲带的几何学研究是造山带研究的热点,但是无论是传统构造地质学方法还是地球物理学方法都在研究褶皱逆冲带几何特征时存在多解性.为了制约这种多解性,本文以天山北麓的呼图壁河剖面为列,介绍一种地质与地球物理相结合的研究方法.该方法首先沿呼图壁河剖面进行详细的地表观测,获取地表的构造地质数据形成初步的地质模型,其次结合地表构造和钻井分层数据,对收集到的石油地震剖面进行重新解释.然而,地震反射数据只分布在盆地内部,在盆山结合带缺失或者不清晰,因此对该剖面进行了重力测量并计算出布格重力异常.结合盆地各沉积地层和基底密度值,用重力正演方法模拟呼图壁河剖面的密度结构.研究结果显示沿呼图壁河剖面并不存在天山北缘断裂,盆地的沉积盖层可以从准噶尔盆地连续过度到天山内部并不整合覆盖在天山古生代基底之上.这一结果与西段金钩河剖面的天山基底逆冲到准噶尔盆地显然不同,说明了天山北缘盆山结合带构造的多样性.利用平衡剖面技术,恢复的呼图壁河平衡剖面缩短量约为4.8 km,对比前人研究,说明了天山北缘的缩短量沿东西方向存在显著的不均一性.本研究也说明这种构造地质与地震及非震地球物理相结合的方法可以广泛地被应用于褶皱逆冲带.