A densely feathered ornithomimid (Dinosauria: Theropoda) from the Upper Cretaceous Dinosaur Park Formation,Alberta, Canada

A recently discovered articulated partial skeleton of Ornithomimus from the Upper Cretaceous Dinosaur Park Formation of Alberta, Canada is remarkable in the extent and quality of preservation of integumentary structures including feathers. It is the first ornithomimid to preserve a tail bearing extensive plumaceous feathers that are slightly more elongate in comparison to those present on the remainder of the body. However, the underside of the tail and the hind limb distal to the middle of the femur appear devoid of plumage. Overall, the plumage pattern in Ornithomimus is similar to that of Struthio camelus (ostrich) and other large palaeognaths, indicating a probable function in thermoregulation. The specimen also preserves the body outline around the legs, including a skin contour anterior to the femur, analogous to skin webs in extant birds. Whereas the knee web of birds bridges the knee to the abdomen, in Ornithomimus it spans from the mid-femoral shaft to the abdomen, and is herein referred to as an anterior femoral web. This is the first report of such soft tissue structures in non-avian theropods. It may indicate that the resting position of the femur was positioned more anteroventrally in ornithomimids than in most theropods, and in that sense may have been transitional to the situation in modern birds.     

新制度经济学视角下高校周边商业街分异研究——以湖南师范大学和湖南大学本部校区为例

高校扩招带来了其周边商业街的蓬勃发展,已有研究从不同角度对其展开论述,新制度经济学的发展与完善为理解高校周边商业街的分异提供了新的可能性。以湖南师范大学和湖南大学本部校区的4条商业街为例,从新制度经济学的角度解释高校周边商业街分异现象,以期丰富新制度经济学视角微观实证研究的内容。实地调研发现,制度对高校周边商业街的分异具有重要作用,正式制度对不同主体的约束作用不同,进而形成一系列非正式制度,从而共同维系了商业街的发展。最后,从制度的角度对高校周边商业街的发展提出了建议。     

A low resolution map of Europa from four occultations by Io

Analysis of three occultations of JII (Europa) by JI (Io) has resulted in a preliminary reflectivity map of JII for the hemisphere centered on longitude 324°, a measurement of 1483±20 km for the radius of JII, estimates of the event impact parameters, determination of the mid event times, and a visual geometric albedo, p_ν = 0.74, for JII. A fourth occultation light curve was used after derivation of the results to confirm their validity.     

几种褐藻中褐藻多糖硫酸酯的分离及分析

分别从３种马尾藻及３份不同产地的海带中提取出褐藻多糖酸酯，并比较了它们的得率和化学组分。得率最高的在大连产海带，为５．５％。马尾藻褐藻多糖硫酸酯组成都很复杂，硫酸根含量都比较低。     

高温下岩石损伤本构模型及其验证

为完善高温条件下的岩石损伤本构模型及参数确定方法,基于有效应力理论,引入Weibull分布函数,在微元体强度服从Hoek-brown准则的条件下,考虑残存强度影响,对损伤变量修正,引入损伤修正系数,建立了能够反映高温作用下的岩石损伤特征统计本构模型。考虑岩石损伤过程中的损伤阈值因素,对本构模型采用分段函数的形式。通过试验,获取常规力学参数,依据本构模型参数求解过程,确定本构模型参数值,并拟合模型参数值与温度之间的关系。对模型理论曲线进行验证。结果表明：提出的高温岩石统计损伤本构模型理论曲线与试验曲线具有较好地相似性,更加贴近试验曲线,体现了本构模型的合理性。同时模型理论曲线与岩石三轴试验曲线具有较高的吻合度,说明本构模型能够反映出岩石的全应力− 应变曲线特征,能够体现出模型的适用性。模型为岩石强度的估算和岩石热损伤软化问题提供了参考。     

唐山市曹妃甸地区大气降尘矿物学特征及环境意义——以华北理工大学校区为例

大气降尘矿物学特征研究具有重要的环境学意义。文章以华北理工大学校区采集样品为例,应用激光粒度分析仪、扫描电镜、X射线粉末衍射、电感耦合等离子体质谱等对河北省唐山市曹妃甸地区大气降尘矿物学特征进行了初步分析研究。结果表明,曹妃甸地区大气降尘粒径较粗,颗粒物包括块状、柱状、片状、球状及不规则粒状集合体,主要由石英、长石、石膏、云母、绿泥石、角闪石、白云石、方解石和赤铁矿等矿物组成;降尘样品中Cr、Cu、Zn、As、Cd、Pb等重金属元素含量均较高。研究分析表明,降尘样品中硅酸盐矿物主要源自地面扬尘,而石膏、方解石等碳酸盐矿物可能为环境中的次生矿物,样品中重金属污染主要来源于燃煤、工矿企业生产排放和少部分汽车尾气排放。     

Teaching Methods,the Herbartian Revolution and Douglas Clay Ridgley at Illinois State Normal University

Abstract

Teaching methods in the 1880s and 1890s were influenced by the energies and publications of the Herbartians from Illinois State Normal University. Memorization was replaced by inductive questioning, field trips and the use of visual aids. Four men and one woman were followed by Douglas Clay Ridgley who built up the geography major and made tools for the teachers. Name recognition is now weak but much of what they taught is now accepted and practiced.     

G. Stanley Hall,Child Study,and the Teaching of Geography

Abstract

G. Stanley Hall (1844-1924), founding president of Clark University, was a leader in the child study movement and a significant figure in psychology and education in the late nineteenth and early twentieth centuries. Hall had pronounced opinions on many educational subjects, including the teaching of geography. His criticisms and program for the reform of school geography were based on a mix of European ideas of heimatkunde or “home geography,” developmental or “genetic” psychology, and his work in the child study and nature study movements. This article traces Hall's involvement with geographic pedagogy from the 1880s through World War I, including his sponsorship of the first American Ph.D. dissertation in the teaching of geography, completed at Clark in 1906.     

南京大学信息地理学的发展回顾与研究展望

信息地理学研究人类信息传播的地理学问题,包括信息传播的空间分布规律、空间结构及其空间影响,特别是对人类社会、经济空间组织的影响以及由于虚拟现实技术带来的地理学问题等。南京大学系统性的展开了信息地理学的研究,并深植于传统的优势地理学科,形成信息时代空间的形态、信息时代的空间效应、数字与信息城市、信息技术与旅游、信息时代的居民行为活动5个重点研究领域。面向全新的移动信息时代,以及信息地理学在社会文化及人文方面的研究不足,南京大学信息地理学面临五大发展趋势:信息技术深入影响下的城市空间研究、移动信息技术作用下的行为地理研究、信息技术与旅游结合的地理学研究、移动信息时代的智慧城市研究、物联网的地理学响应研究。     

广州金沙洲广州大学附属实验学校地面沉降形成机理研究

依据地下水动态监测、地面沉降监测和地质钻探的成果,综合研究广州市金沙洲广州大学附属实验学校地面沉降地带的地质构造、人类工程活动特征、岩土体类型、第四系厚度、地层与岩石等因素对地面沉降的影响,分析研究区内地面沉降的动态演变特征。结果表明:脆弱的地质环境条件是广州大学附属实验学校地面沉降形成的内在因素,开挖基坑、桩基础施工及抽排地下水是地面沉降形成的外在因素。在此基础上,得出学校地面沉降是因软土层在抽排地下水及地面附加荷载的共同作用下产生排水固结的结果。