Interdecadal variability of anchoveta abundance and overcapacity of the fishery in Peru

Paleontological and historical stock abundance estimates indicate that pelagic fish populations inhabiting upwelling ecosystems undergo large interdecadal variations in abundance with amplitudes equal to, if not larger than, the interannual variability. The interdecadal variability is characterized by periods of high and low abundance, termed “pseudo-cycles”, because of their irregular periodicity. Fisheries targeting small pelagic fish suffer from overall overcapitalization, like many other fisheries, but also from an additional overcapitalization problem: a phase displacement between rapid fish population decreases and a slower disinvestment which follows. This lag produces economic hardship.Here we document the fish:fishery relationship for the Peruvian anchoveta. Anchoveta pseudo-cycles of 20 to >100 years are observed, with the present stock abundance most likely located near upper part of the cycle. Fleet overcapacity expressed as the proportion of unused present capacity is estimated at 72% and processing overcapacity at 89%. A simple bio-economic model demonstrates the risks associated with the pseudo-periodicity in fish stock abundance in conjunction with fishery investment, open access, and overcapacity: a timing bomb for the fishing sector. The lag between disinvestment and decrease in fish abundance is quantified. A reduction of the fishing and processing capacity and measures to decrease the investment lag are recommended to limit the social, economical and political tensions that will result from the expected decrease in stock abundance. Finally, some management options to reduce these risks are discussed.     

Analysis of Ore-Controlling Structures of the Xincheng-Hexi Gold Deposit, Shandong Province, China

Based on quantitative and semi-quantitative mathematical and mechanical analysis of the shape, motion, structural factors, stress field and deformation field of the ore-hosting faults in the Xincheng-Hexi gold deposit, the ore-controlling features of faults and mineralization mechanism are discussed. It is concluded that the mineralization is controlled by the main faults, subsidiary fractures, joint density, mechanical features and deformation of the faults. The ore bodies are mainly located in the lower part of the convex crest and upper part of the concave trough of the main undulating fault surface. Mineralization is positively correlated to the development of subsidiary fractures and joints, which correspond to zones of low internal stress and high body strain and shear strain. They are favourable positions for mineralization and alteration.     

全国地层委员会章程

第一条　宗　旨为了适应国民经济建设和地质科学发展的需要，推动中国地层工作和地层学的健康发展，更好地发挥全国地层委员会（以下简称全委会）的作用，特制定本章程。第二条　性质与任务全国地层委员会是国家地矿主管部门——国土资源部领导下的全国性学术协调组织。其任务是：1.讨论制定地层工作和地层学研究的基本任务和发展方向；协调地层工作发展规划。2.组织起草、修订《中国地层指南》；负责全国地层单位名称的管理。3.组织交流地层工作的成果和经验，开展国内外学术交流；组织、协调有关重大的地层科学技术问题的解决；编辑出版《…     

Long slit spectroscopy of the nuclear zone of NGC 253

We have undertaken a study of the physical conditions of the lonized gas within the starburst region of the galaxy NGC 253, using long slit spectroscopy at high spatial and spectral resolution. Our aim was to identify the appropriate parameters describing the dynamics of the gas and the excitation conditions, in relation with the starburst process. Non-gaussian line profiles and line spliting are clearly observed, indicating a complicated dynamical structure; furthermore, the zones presenting non-circular motions and localized outflow of gas have been spatially sampled at the seeing limit.Paper presented at the 11th European Regional Astronomical Meetings of the IAU on New Windows to the Universe, held 3–8 July, 1989, Tenerife, Canary Islands, Spain.     

Dynamics Behind Cycles and Co-movements in Metal Prices: An Empirical Study Using Band-Pass Filters

After living one of the most intense metal price cycles, several ongoing macroeconomic phenomena with the potential of structurally redefining the long-run supply and demand for metals, and raising divergency regarding where the metal prices are trending, it is suitable to evaluate the dynamics in the metal prices, especially focus on the long cyclical components. This article studies in detail the cyclical components of the real prices of base metals, iron ore, and gold, applying band-pass filters and a novel decomposition over time series with length as far as 1800. The main findings are: (1) the long cyclical components in real prices are highly correlated among them and with the proposed long economic cycles, (2) short and medium cyclical components are more relevant in explaining the price deviations from their trend, but the long cyclical component is not negligible, (3) co-movement in base metals is strong for all the cyclical components, but decreasing as cyclical frequency increases, and (4) prices are either sideways or upward-trending depending on the assumptions for correction of the US Consumer Price Index, which suggests that the supply side of these industries, in the best case, only offset the cost increases by depletion.

     

梁柱-板柱组合结构(住宅)体系模型振动台试验研究

梁柱-板柱组合结构(住宅)体系由上部大开间板柱结构和底部框架结构构成，是一种可持续发展的新型结构形式。通过两个12层l：15模型的振动台对比试验，探讨其动力特性、地震反应和破坏情况。试验表明，该体系的抗震性能介于框架结构和板柱结构之间。总层数在12层以下时，不设剪力墙的该体系在7度区基本上满足规范要求，合理设置剪力墙后可用于8度区。     

重大工程地震安评工作中的历史地震资料使用问题专题研讨会在合肥召开

历史地震资料的使用对重大工程地震安全性评价结果有相当大的影响，在地震构造活动较弱的中强地震活动地区这种影响尤为显著。近年来沿长江各省的核电选址工作，凸现了这一问题的重要性。为此，中国地震局震害防御司和中国地震学会历史地震专业委员会于2004年10月12—16日在安徽省合肥市召开了“重大工程地震安评工作中的历史地震资料使用问题专题研讨会”，安徽省地震局黄田庚局长、张鹏副局长、中国地震     

Floor-age constraining of a tectonic paroxysm of the Pyrenean orogen. Late Middle Eocene mammal age of a faulted karstic filling of the Quercy phosphorites,south-western France

Abstract

Breaking effects of a Pyrenean compressive tectonic phase are recognised in northern Pyrenean foreland, such as in the Quercy Jurassic limestone platform. The age of this phase still remains poorly constrained. In the so-called Quercy phosphorites area, within the Prajoux—Mémerlin paleokarst system near the city of Cajarc, a clay filling shows a strike slip fault effect, close to N-S direction. According to an analysis of the mammal fauna and inferred chronology of the polyphased paleokarst infilling, the age of the faulted clay is late Middle Eocene, with a mammal age estimate of 41.5 Ma. This provides reliable precise floor-age constraining for the involved sismo-tectonic paroxysm, seemingly related to the Pyrenean tectonic compressive phase. © 2000 Editions scientifiques et médicales Elsevier SAS     

关于地震预测研究的争论(一)

编者按: 英国<自然>杂志(Nature)于1999年2月25日至4月8日在因特网上组织了一次主题为"单个地震的可靠预测是一个现实的科学目标吗?"(Is the reliable prediction of individual earthquakes a realistic scientific goal?)的争论,争论发起人Ian Main写了该次争论的第一篇引论文章,以后陆续有短文和E-mail通讯意见计24篇在此争论栏目中发表.