中新世黄河水系演化重建：来自钾长石Pb同位素的约束

自剥蚀地貌中形成的剥蚀产物搬运到沉积区或汇水盆地沉积下来的过程,称为“源-汇”系统。从这些“汇”中识别“源”的信息,结合地层的沉积时代,约束黄河的形成时代、水系格局演化、流域内构造运动以及环境变迁成为黄河水系演化研究的重要内容。然而,时至今日学者们对黄河何时出现的认识并不一致,存在“中新世内流黄河和中新世外流黄河”之争。为了解决这些争议,我们运用大河物源示踪研究中新兴的碎屑钾长石Pb同位素方法,对黄河中下游沉积物开展碎屑钾长石Pb同位素分析(n=378),将其与长江中下游和华夏板块已报道的碎屑和基岩钾长石Pb同位素结果进行对比,结果表明三者之间的钾长石Pb同位素组成明显不同。台湾岛是中国东部陆架海中新世地层出露最齐全的地区。因而,我们将黄河中下游与台湾岛中新统的钾长石Pb同位素比值进行对比,结果表明二者之间不存在物源联系。结合中国东部渤海湾盆地、南黄海盆地和东海盆地中新统的物源示踪研究结果,说明黄河物质在中新世未流入上述盆地。总体而言,中国北方中新世的构造活动控制了黄河的演化过程,导致其此时处于分段演化阶段。     

Reform of Teacher Education: An Opportunity for Geographers

Abstract

This paper focuses on the context and major efforts designed to reform teacher education in the nation's universities. An overview of systems governing and impacting teacher education is provided, with focus on the issues and conflicting forces that form the context within which teacher education-and geography education—find themselves. The paper concludes with a discussion of general trends in education reform and renewal and leadership opportunities open to geographers.     

GIS in the K-12 Curriculum: A Cautionary Note

Two qualitative case studies, one focusing on K-12 teachers and the other on middle school students, explore key factors associated with using Geographic Information Systems in the classroom. In both studies, access to appropriate hardware is a critical barrier. Time is another critical barrier—time to learn the GIS software and time in the curriculum to incorporate GIS as a learning experience. In both case studies, learning the technology at the expense of learning spatial analysis was a danger, suggesting the need for conscious focus on the goal of using GIS to learn how to “do geography.”     

基于K-Means聚类的辽宁省主体功能区试划研究

在国家提出的新的主体功能区概念体系和划分思路前提下,基于辽宁省主体功能区划定要求的8个基本指标项定量综合评价基础数据,选择“典型的”优化开发区、重点开发区、农产品主产区和重点生态功能区,采用K-Means聚类方法,分别在不指定初始聚类中心、指定初始聚类中心、以及PCA分析（即主成份分析）基础上指定初始聚类中心3种方法,对于全省100个县市区做4类主体功能区试划分.分别将划分结果与全省最终采用的划分方案进行比较,结果表明采用在PCA分析基础上指定初始聚类中心技术方法的划分结果更接近最终采用方案.     

Interaction of particles in the near field and opposition effects in regolith-like surfaces

The explanation of the opposition effects observed in brightness and polarization in different celestial bodies and laboratory samples is still far from being complete. The shadow hiding and coherent backscattering mechanisms are mentioned most frequently in this connection. In the present work, we consider one more scattering mechanism—the interaction of particles in the near field—and its influence on the brightness and polarization of light scattered by ensembles of particles at small phase angles. First, we analyze two manifestations of this mechanism: the field inhomogeneity in the vicinity of the scatterers and the shielding of particles by each other at distances compared with their sizes. Then, we use the model regolith described as an ensemble of clusters as constituents and compare the contributions of the coherent backscattering and the near-field effect to the intensity and polarization of light when the porosity of the ensemble is varied. The modeling confirms that the phase dependences of the intensity and polarization of light scattered by complex structures in the backscattering domain is mainly caused by these two mechanisms. The coherent backscattering works more effectively in sparse media, while the near-field effect manifests itself in more compact ensembles of wavelength-sized particles. However, it is difficult to distinguish quantitatively their contributions, even in models of simple structures. A number of observations, especially of moderate- and low-albedo objects, can be explained only by invoking the near-field effect.     

成分数据理论和无监督聚类K- means方法提取背景和异常信息——以安徽省兆吉口铅锌矿床为例

地球化学数据是应用地球化学研究的重要组成部分，是化学勘查工作的基础成果。勘查地球化学数据基本上以元素的质量百分浓度 (简称浓度)的形式表达，是典型的成分数据。其表达的是“组分/总体”相对质量贡献信息，而不是绝对的质量变化信息。浓度数据分布在单纯形空间，而不是整个欧式空间。对成分数据进行处理之前，进行适当的对数比值转换处理可以提高其信息表达。本文以安徽省兆吉口铅锌矿床土壤中Pb数据为示范案例，通过对数比值转换方法优化浓度数据的结构以提高相对信息的表达，并利用无监督学习K- means聚类方法根据对数比值转换数据分布空间质心的距离识别背景和异常信息，最后对K- means聚类方法识别的背景和异常与迭代2倍标准差法和浓度- 面积分形分析法进行比较以衡量其表现。结果表明：浓度数据表达的是相对质量信息，而不是绝对质量关系，不同样品间不能通过比较浓度高低推断出质量的多寡关系。对数比值方法可以有效地提高浓度数据的结构和信息表达，K- means方法能够准确识别对数比值转换数据的背景和异常信息，其效果类似浓度- 面积分形分析方法，比迭代2倍标准差法好。     

The value of teaching about geomorphology in non-traditional settings

Academics usually teach about geomorphology in the classroom, where the audience is enthusiastic, but generally small. Less traditional settings offer opportunities to reach a wider audience, one that is equally enthusiastic, given its love of geomorphic features in the National Parks, but one which has little knowledge of the science behind what they are seeing. I have “taught” geomorphology in four non-traditional settings: at a summer camp, a state wildlife refuge, on community field trips, and at meetings for clubs and government boards. This paper discusses my experiences and offers suggestions to others who may wish to follow this less-traveled educational path.As Head of Nature Programs at Camp Pemigewassett in New Hampshire, I have worked, over the last 33 years, with thousands of campers ranging from 8 to 15 years old. Our setting, in a glaciated valley on a small lake, exhibits a wide range of geomorphic features and offers many opportunities for direct learning through field investigations. I have found that even 8-year olds can do real science, if we avoid the jargon. Once “taught” they carry their knowledge about landforms and processes with them and eagerly share it with their friends and family on outings and trips, thus reaching an even wider public.Parks, wildlife refuges, nature preserves, and other similar areas generally have nature trails, often with educational information about the environment. Generally, interpretive signs are prepared by biologists and the content ignores the site's physical features, as well as the connections between ecological communities and the underlying geology and geomorphology. My students and I have addressed this situation at two places in Connecticut, one a state wildlife management area, also used for training teachers to teach Environmental Education, and the other, a town recreation area. We catalogued the geomorphic features, looked at relationships of the community level ecology to those features, and prepared interpretive signs that added this perspective to the trails. The public response has been extremely favorable.Geomorphology can also be taught by leading field trips for community organizations. I have done this twice, once for the Manchester (NH) Historical Society and once for a small watershed association. The attendance and interest surprised me. We finally had to limit the Manchester trip to one full busload (45) and the watershed trip, which was part of a “trails day,” drew over 90 people.Finally, I have found that organizations such as Sierra Club chapters and town conservation boards are frequently looking for speakers for their periodic meetings. Why not a geomorphologist? After all, much of what conservationists do is related to what geomorphologists do. I have given several of these presentations and the receptions have always been enthusiastic.While the work involved in preparing to teach in one of these non-traditional settings is frequently substantial, the rewards are equally large. It is a way to reach masses of people who know little about the science of geomorphology and to demonstrate its importance to them. Taking our message directly to the public in these settings is an effective way to put geomorphology in the public eye.     

How the States Got Their Shapes

Abstract

A baseline geography test was administered to over 3,000 Indiana college students enrolled in introductory geography courses. The National Council for Geographic Education Competency-Based Geography Test, Secondary Level, Form II, was used to measure the 1987 level of geographic ability in the areas of map skills, place-name location, physical geography, and human geography. Personal information gathered from each respondent included age, sex, travel experience, and level of geographic education. Older students scored better while geographically immobile groups scored lower. A strong correlation was found between travel and geographic knowledge. Findings show low overall geographic ability and that factors of age, travel experience and gender are correlated with certain aspects of geographic knowledge and skills.     

Exploring Cultural Universals

Abstract

This article identifies teaching strategies to explore cultural universals. Traits that contribute to distinguishing one culture from another can be classified into general categories that all cultures share. Students identify universals in their daily lives and then compare and contrast different cultural perspectives through an exploration of these universals. Computer technology provides access to images and information about other cultures that might be used to increase students' understanding of cultural perspectives. The Internet provides a vehicle for classrooms to exchange cooperative creative writing stories that allow students the opportunity to explore different cultural perspectives through the eyes of other students around the world. Suggestions about how to establish and conduct a classroom exchange project over the Internet are provided.     

辽河东部凹陷火成岩测井岩性识别方法与应用

采用基于K-means聚类算法的RBF神经网络法对辽河盆地东部凹陷火成岩岩性进行识别。综合利用自然伽马、补偿中子、声波时差、密度与电阻率的实际测井资料,建立火成岩岩性识别的基础RBF神经网络。选取有岩芯和岩屑记录的若干井次试验验证,该方法清楚地识别出了玄武岩、粗面岩等6种火成岩,识别准确率平均可达70%以上。