Transdisciplinary co-operation for an ecosystem approach to fisheries: A case study from the South African sardine fishery

Integrative approaches that involve natural and social scientists are needed to manage fisheries, but these are difficult to achieve. The process of developing a prototype, knowledge-based, electronic decision support tool for the South African sardine Sardinops sagax fishery provided a platform for fostering collaboration and achieving active participation of many stakeholders. The aim of the decision support tool is to assist managers in evaluating how effectively an ecosystem approach to fisheries (EAF) has been implemented for this fishery. The collaborative process involved a series of meetings during which knowledge was elicited from fisheries scientists, social scientists, resource managers and fishing industry representatives. Conceptualisations of the different stakeholder perspectives were developed in terms of objectives and indicators following the hierarchical tree approach recommended by FAO. This paper describes the collaborative process. Hierarchies of objectives, indicators and data sets for the human dimension of an EAF in the South African sardine fishery are introduced. The value of a transdisciplinary approach towards an EAF in South Africa is discussed.     

Ice-wedge casts and relict polygonal patterns in Scandinavia

Ice-wedge casts in Scandinavia frequently occur in three regions: (a) southwestern Jutland (outside the limit of the Weichselian glaciation); (b) southwestern Sweden; and (c) northernmost Norway. The latter two areas are both early deglaciated regions. Characteristics of casts in vertical sections are discussed with reference to the host and infilling material. Aerial photographs provide an effective tool for detecting relict ice-wedge polygons (crop marks, micromorphology). Experience from present-day permafrost regions with active ice-wedge formation helps to explain the palaeoclimatic significance of the relict polygons. Attempts to establish the ages of formation are discussed from a methodological point of view.     

Giant iceberg plow marks at more than 1 km water depth offshore West Greenland

During a recent (2006) cruise of RV ‘Dana’ high resolution side-scan sonar and sub-bottom profiling was carried out on selected shelf and slope transects offshore Disko Bugt, central West Greenland. Available commercial seismic data from the margin indicate here irregular seabed morphology with erosional features locally extending down to c. 1100 m water depth. The newly acquired side-scan sonar data reveal the presence of giant iceberg plow marks extending (sub)parallel to the slope between about 800 and 1085 m water depth. The height difference between bottom of the scours and rim crest is up to 40 m. The largest plow marks are about 750 m wide. To date no observed modern icebergs including those from Antarctica have drafts in excess of c. 500 m. Taking into account maximum glacial sea level lowering of c. 120 m, the paleo-iceberg keel depth was at least 950 m. Due to the presence of the relatively shallow (< 700 m) sill of Davis Strait to the south, calving of these paleo-icebergs is thought to have occurred from an ice margin in the Baffin Bay region (Jakobshavn Isbræ paleo-ice stream?). The depth of occurrence (> 1000 m) and dimensions of the plow marks are concluded to be exceptional, and comparable to glacial scouring features reported from the Arctic Ocean.     

中国城市群人口老龄化时空格局

老龄化和城市化是当今世界面临的两大人口问题。城市群是城市发展到成熟阶段的空间组织形态,是老龄化的特殊区域。本文基于2000年和2010年全国人口普查分县数据,综合应用地理探测器和变异系数等方法,清晰地刻画了中国20个城市群人口老龄化的空间格局及其变化特征,审视了人口老龄化变化的影响因素。结果表明：① 2000年中国城市群人口老龄化平均水平为7.32%,其中12个城市群的人口属于成年型,到2010年时人口老龄化平均水平已上升为9.00%,除珠三角与宁夏沿黄城市群外,其余18个城市群均步入了老年型人口,表现出明显的水平升级与类型替变态势。② 老龄化高值、较高值区域不断向内陆城市群跃迁。③ 城市群老龄化的增量和增速存在显著的区域差异,老龄化水平的低值区和高值区增量少、增速慢,而较低值、中值和较高值区增量多、增速快。总体上表现出区域性城市群——国家级城市群——地区性城市群老龄化速度递减的态势。④ 在城市群内部,老龄化分布格局表现出隆升—塌缩并存的现象。国家级城市群内部老龄化分布格局从隆升结构向塌缩结构转变,城市群中心区人口老龄化水平降低;而地区性城市群和区域性城市群内部老龄化分布格局则从均质结构向隆升结构转变,中心区人口老龄化水平上升。⑤ 城市群人口老龄化是内外因素综合影响的结果,基期老龄化程度、人口年龄结构替变和人口流动性是主导性因素。其中人口年龄结构的普遍性抬升是城市群老龄化升级与类型替变的关键,低龄人口迁入到城市群对人口老龄化则起到“稀释作用”,城市群发育阶段不同引致的聚集和扩散效应对老龄化则起到诱导作用。     

湖南古丈县万岩重晶石矿床地质特征及找矿前景

古丈县万岩重晶石矿点是开展湖南古丈地区矿产地质调查过程中新发现的矿点。本区重晶石矿属低温热液型矿床,成矿完全受裂隙控制。矿体主要赋存于震旦系上统金家洞组(Z2j)地层中,该地层中部的磷矿和底部的黄铁矿均在野外易于识别,且与重晶石矿体有着较为密切的空间关系,对找矿有着重要的指示作用。万岩重晶石矿点以东地区具一定的找矿前景。     

喷射式局部反循环绳索取心钻具

针对金矿复杂破碎地层钻探存在的岩心采取困难、孔内漏失严重等问题,改进绳索取心钻具,增加了局部反循环装置,研制出一套适应性广、取心可靠的可调喷射反循环钻具,提高岩心采取率,取得了良好的效果。介绍了该钻具的结构原理、适应范围及应用效果。     

湖北郧西白龙洞遗址骨化石表面痕迹研究

湖北省郧西县白龙洞古人类遗址属于中更新世早期,发掘出表面带有痕迹的骨化石标本。使用肉眼裸视观察法、低倍显微观察法、高倍显微观察法、三维扫描数字模型技术等多种观测分析法进行综合研究,鉴定出痕迹种类包括人工改造痕迹和其他动物改造痕迹。人工改造痕迹包括锤击痕迹、切割痕迹、砍斫痕迹、戳刺痕迹等,其中锤击痕迹主要出现在骨器表面(用于骨器制造),其他痕迹则出现在多种骨骼部位的残片上(可能由狩猎、屠宰、分割和剥皮行为产生)。动物改造痕迹包括食肉目动物啃咬痕、偶蹄目动物踩踏痕、啮齿目动物啃咬痕等。其中制造啃咬痕的啮齿目动物中,可能包括有豪猪、竹鼠和鼠科动物等。人工改造痕迹的研究对认识当时人行为模式提供了具体证据,如当时人对洞穴占据使用形式、骨质工具制造与使用、狩猎与分食行为(狩猎工具与剥皮技巧)等。本研究对其他动物改造痕迹也作了必要分析,如豪猪与鼠科动物的不同啃啮形态等。该遗址研究、鉴定出的多种痕迹标本,以及多种鉴定、分析方法的使用等,显示出古人类遗址中痕迹标本的复杂性,以及多种研究方法的必要性。三维扫描数字模型技术,是国内在该领域研究方法中的首次使用。     

预应力锚索孔内扩孔工艺的研究

预应力锚索技术是进行滑坡治理、边坡锚固等地质灾害治理中的常用技术,传统锚索内锚头自由地搁置在内锚固段孔内,在无预应力状态下进行内锚固段注浆;而自承载式预应力锚索在有预应力的状态下注浆,有利于充分发挥浆体材料及岩体的力学性能。对于中硬以下碎裂岩层,采取在锚固段进行扩孔,在扩孔段安装自承载式锚索承载体,承载体扩体后,利用孔壁的摩擦力和扩孔段端部的承载力进行初张拉锁定。因此,研究了一种适用于中硬以下岩层（抗压强度＜30 MPa）且适合使用空气潜孔锤钻进工艺的扩孔钻具和钻孔工艺,通过进行扩孔钻进室内试验,结果表明,该扩孔钻具和工艺能够实现在锚固段进行分段扩孔。     

高效、低耗冲击式凿岩钎具——工业炸药发明后困扰世界采掘工业的百年难题

15 0年前瑞典诺贝尔父子继中国火药之后, 发明了硝化甘油胶质炸药用于修路与采矿, 引发了导致社会财富高速增长的“真正意义的工业革命”.192 3年德国施律泰尔发明WC -Co硬质合金, 迅速形成了硬质合金切削刃具和硬质合金凿岩钎具两大产业, 使机械和采掘工业飞速发展, 被誉为“工业的牙齿”.迄今, 现代化的凿岩爆破技术, 已成为人类向岩石圈索取资源和向地下开拓生存与发展空间的主要手段.其中, 用在岩矿石中冲击凿孔的凿岩钎具, 是人类所有机械工具中受力条件最苛刻、使用寿命最短、基础工业必备、技术含量很高的大量消耗性工具.研制长寿命冲击凿岩钎具, 已成为全球采掘工业高效、低耗凿岩必须解决的新世纪重大工程技术难题.这需要凿岩、爆破、岩石破碎、矿业、材料、冶金、钢铁、机械、物理、化工、电子、数学、力学、生物(仿生) 等各方面专家的长期通力合作.建设以“新型硬质合金钎具”和“长寿命冲击凿岩钎杆”为标志的有中国特色的现代化凿岩钎具工业, 是我国新一代“资源-高科技-外向型”民族工业一个具有战略意义的新生长点      

An improved process-based representation of stream solute transport in the soil and water assessment tools

Hydrological models have long been used to study the interactions between land, surface and groundwater systems, and to predict and manage water quantity and quality. The soil and water assessment tool (SWAT), a widely used hydrological model, can simulate various ecohydrological processes on land and subsequently route the water quality constituents through surface and subsurface waters. So far, in-stream solute transport algorithms of the SWAT model have only been minimally revised, even though it has been acknowledged that an improvement of in-stream process representation can contribute to better model performance with respect to water quality. In this study, we aim to incorporate a new and improved solute transport model into the SWAT model framework. The new process-based model was developed using in-stream process equations from two well established models—the One-dimensional Transport with Inflow and Storage model and the Enhanced Stream Water Quality Model. The modified SWAT model (Mir-SWAT) was tested for water quality predictions in a study watershed in Germany. Compared to the standard SWAT model, Mir-SWAT improved dissolved oxygen (DO) predictions by removing extreme low values of DO (<6 mg/L) simulated by SWAT. Phosphate concentration peaks were reduced during high flows and a better match of daily predicted and measured values was attained using the Mir-SWAT model (R² = 0.17, NSE = −0.65, RSR = 1.29 with SWAT; R² = 0.28, NSE = −0.04, RSR = 1.02 with Mir-SWAT). In addition, Mir-SWAT performed better than the SWAT model in terms of Chlorophyll-a content particularly during winter months, improving the NSE and RSR for monthly average Chl-a by 74 and 42%, respectively. With the new model improvements, we aim to increase confidence in the stream solute transport component of the model, improve the understanding of nutrient dynamics in the stream, and to extend the applicability of SWAT for reach-scale analysis and management.