Latitudinal Range Variation of Trees in the United States: A Reanalysis of the Applicability of Rapoport's Rule*

In 1975 E. H. Rapoport described a pattern of increasing latitudinal range sizes for organisms with increasing latitude, a pattern that is now known as Rapoport's rule. The universal applicability of Rapoport's rule has been long contested, making it one of the more controversial biogeographic “rules.” This study aims to reassess the applicability of Rapoport's rule to U.S. tree species. Data presented here suggest that Rapoport's rule does indeed apply to most tree taxa within the United States, but may be taxon specific. In addition, data presented here suggest that tree range patterns consistent with Rapoport's rule in the United States are not restricted to high latitudes and are not the result of a “boundedness effect” but may be intimately linked with the glacial history and physical geography of North America. The analyses conducted here are intended to emphasize the utility of such biogeographic rules even if they are not universally applicable and should, in turn, only be considered biogeographic patterns.     

Optimization of operation rule curves and flushing schedule in a reservoir

Flushing sediment through a reservoir has been practiced successfully and found to be inexpensive in many cases. However, the great amount of water consumed in the flushing operation might affect the water supply. To satisfy the water demand and water consumed in the flushing operation, two models combining the reservoir simulation model and the sediment flushing model are established. In the reservoir simulation model, the genetic algorithm (GA) is used to optimize and determine the flushing operation rule curves. The sediment‐flushing model is developed to estimate the amount of the flushed sediment volume, and the simulated results update the elevation‐storage curve, which can be taken into account in the reservoir simulation model. The models are successfully applied to the Tapu reservoir, which has faced serious sedimentation problems. Based on 36 years historical sequential data, the results show that (i) the simulated flushing operation rule curves model has superior performance, in terms of lower shortage index (SI) and higher flushing efficiency (FE), than that by the original reservoir operation; (ii) the rational and riskless flushing schedule for the Tapu reservoir is suggested to be set within an interval of every 2 or 4 years in the months of May or June. Copyright © 2003 John Wiley & Sons, Ltd.     

新疆天山北坡干旱区GDP时空模拟

针对资源环境研究领域对空间型社会经济数据的需求,本文以新疆天山北坡为试验区,在分析区域经济发展特征的基础上,根据分县控制、分产业建模的思路,建立基于土地利用的1 km栅格GDP空间化模型对统计型经济数据进行空间分布仿真模拟。对第一产业产值采用面积权重的方法进行拟合;对第二产业建立基于道路的反距离加权模型;第三产业则以城镇规模为基础,通过引入城市边缘距离概念建立多中心的距离衰减加幂指数模型。结果表明,天山北坡GDP空间分布模拟在分产业和分县水平上具有较高精度,模拟值与真实值间的相对误差均在1%以内。从研究区GDP的空间分布来看,高值区主要集中在米泉至沙湾一线,以乌鲁木齐市、石河子市以及克拉玛依市为核心向周围地区辐射;城市内部GDP密度由城市中心向外围递减,建成区GDP密度明显高于城郊及农村地区。1995、2000和2007年三期GDP模拟结果的对比较真实地反映了区域经济发展的历程,对准确把握区域经济动态具有一定的实用价值。     

A Test and Re-Estimation of Taylor’s Empirical Capacity–Reserve Relationship

In 1977, Taylor proposed a constant elasticity model relating capacity choice in mines to reserves. A test of this model using a very large (n = 1,195) dataset confirms its validity but obtains significantly different estimated values for the model coefficients. Capacity is somewhat inelastic with respect to reserves, with an elasticity of 0.65 estimated for open-pit plus block-cave underground mines and 0.56 for all other underground mines. These new estimates should be useful for capacity determinations as scoping studies and as a starting point for feasibility studies. The results are robust over a wide range of deposit types, deposit sizes, and time, consistent with physical constraints on mine capacity that are largely independent of technology.     

Hotelling Revisited: Oil Prices and Endogenous Technological Progress

This article examines the Hotelling model of optimal nonrenewable resource extraction in light of empirical evidence that petroleum and minerals prices have been trendless despite resource scarcity. In particular, we examine how endogenous technology-induced shifts in the cost function would have evolved over time if they were to maintain a constant market price for nonrenewable resources. We calibrate our model using empirical data on world oil, and find that, depending on the estimate of the initial stock of reserve, oil reserves will likely be depleted some time between the years 2040 and 2075.     

自DEM由不同算法提取坡度的对比分析

以陕北韭园沟流域1:10 000水平分辨率为5 m的DEM为研究对象,运用方差分析、回归分析、排序分析等分析方法,采用6种不同算法分别提取坡度。通过比较不同算法所提取坡度的平均值、最大值、标准差、坡度的中误差,定量分析中误差与地形变化的关系后,提出在黄土丘陵沟壑区提取坡度时选用三阶反距离平方权差分算法和三阶反距离权差分较为合理。     

中上扬子地区碳酸盐岩储层发育分布规律及主控因素

以构造一层序地层学理论和动态演化现为指导,对中上扬子区震旦纪-中三叠世储层发育分布规律进行新一轮的分析,认为纵向上碳酸盐岩储层与层序格架发育具有良好的对应关系,即对应于全球二级海平面变化旋回中的高水位体系域;储层非均质性强;下古生界以溶蚀、岩溶、白云化和构造缝形成的次生孔隙为主要储集空间,上古生界原生孔和次生孔均为储集空间.横向上层序格架内储层发育和分布的有利区域具有差异性;优质储层多发育于潮坪、缓坡、岩溶斜坡和台内、台缘礁滩环境中,且与白云化作用、溶蚀作用、岩溶作用和构造改造作用密切相关;上二叠统-中三叠统储层分布在纵横向上均具有特殊性.综合分析认为层序地层格架控制了碳酸盐岩储层发育和分布规律,即主要储层的发育与全球二级海平面升降旋回中的高位期具有明显的一致性,而且二级海平面旋回中的三级海侵旋回也为有利区域性储层发育的层位;海退旋回的晚期有利于古岩溶型的碳酸盐岩储层发育,而海侵旋回的初期-早期,有利于台地边缘或台内滨外滩的碳酸盐岩储层发育;层序格架中的高能沉积环境、有利的岩溶和成岩环境,以及构造复合作用是形成优质储层的主控因素.     

A tale of two species: Extirpation and range expansion during the late Quaternary in an extreme environment

Death Valley, California is today the hottest hyperarid area in the western Hemisphere with temperatures of 57 °C (134 °F) recorded. During the late Quaternary, pluvial Lake Manly covered much of the Valley and contributed to a much more moderate climate. The abrupt draining of Lake Manly in the mid-Holocene and coincident dramatic shifts in temperature and aridity exerted substantial selection pressure on organisms living in this area. Our research investigates the adaptive response of Neotoma (woodrats) to temperature change over the late Quaternary along a steep elevational and environmental gradient. By combining fieldwork, examination of museum specimens, and collection of paleomiddens, our project reconstructs the divergent evolutionary histories of animals from the valley floor and nearby mountain gradients (− 84 to > 3400 m). We report on recent paleomidden work investigating a transition zone in the Grapevine Mountains (Amargosa Range) for two species of woodrats differing significantly in size and habitat preferences: N. lepida, the desert woodrat, and N. cinerea, the bushy-tailed woodrat. Here, at the limits of these species' thermal and ecological thresholds, we demonstrate dramatic fluctuations in the range boundaries over the Holocene as climate shifted. Moreover, we find fundamental differences in the adaptive response of these two species related to the elevation of the site and local microclimate. Results indicate that although N. cinerea are currently extirpated in this area, they were ubiquitous throughout the late Pleistocene and into the middle Holocene. They adapted to climate shifts over this period by phenotypic changes in body mass, as has been demonstrated for other areas within their range; during colder episodes they were larger, and during warmer intervals, animals were smaller. Their presence may have been tied into a much more widespread historical distribution of juniper (Juniperus sp.); we document a downward displacement of approximately 1000 m relative to juniper's modern extent in the Amargosa Range. These results suggest a cooler and more mesic habitat association persisting for longer and at lower elevations than previously reported.     

断陷盆地输导体系类型及控藏机制

断陷盆地输导体系是连接源岩和圈闭的纽带,是油气成藏静态要素和动态过程的统一体。输导体系按构成分为断裂型、砂体型、不整合面型和复合型;按有效性分为有效输导体系和高效输导体系;按识别难易程度分为输导体系和隐蔽输导体系。输导体系空间展布控制油气藏网格状分布,输导体系时空有效性控制油气运聚,隐蔽输导体系控制洼陷带岩性圈闭成藏。断陷盆地输导体系精细研究及其控藏机制对在成熟探区开拓勘探空间、寻找剩余油气藏具有重要的理论和应用价值。     

基于规则库的三维地质自动建模技术研究

利用规则统一三维实体间的语义形式化表达,为建模提供统一的方法。利用三维矢量数据模型的框架,对直钻孔、斜孔、剖面、等值线、断层、褶皱等数据源,分别按规则制定一种数据格式,对多源地质数据进行标准化和信息融合,经过地质面和地质体的快速构建,提出了建立基于规则库的三维矢量数据模型。同时研究了适合各类地质特点的三维模型自动构建方法,包含多源数据耦合层状地质体自动建模技术、基于剖面单元格划分的分区—拼接自动建模技术、多约束下复杂地质结构快速建模技术、空间约束条件下三维地质属性建模技术等。在确保模型精度的前提下,尽量减少人工交互建模的工作量,提高了建模效率。