甘肃的寒武系

寒武系主要分布于北山、祁连山、河西走廊及陕甘宁盆地。根据沉积岩相及动物地理区系分为三大沉积区和７个沉积分区：北山沉积区分为下统双鹰山组、中统大豁落井组、上统西双鹰山组；祁连山沉积区未见下统，中统月牙山群、黑茨沟群和格尔莫沟群，上统香毛山群；华北沉积区下统未分，中统毛庄组、徐庄组和张夏组，上统仅见崮山组。三大沉积区的动物群分别为东南型（除早寒武世外）、过渡型和华北型。寒武系下界相当于滇东的沧浪铺阶之底界，并与震旦系冰碛层呈平行不整合接触。寒武纪岩相古地理轮廓受当时的地壳变动和气候条件所控制。早寒武世中晚期开始海侵，在北山沉积区之西部呈海湾，在陕甘宁盆地西缘呈浅海陆棚，省内其余地区（除西秦岭外）呈古陆状态。中寒武世广泛海侵，在祁连山形成海槽，且地壳运动加剧，火山喷发活动频繁。晚寒武世大规模海退，仅在北山局部地区、祁连山西段和陕甘宁盆地有沉积，其余均为古陆状态。     

Forgotten coast,forgotten people: sustainable development and disproportionate impacts from Hurricane Michael in Gulf County,Florida

Natural Hazards - A central challenge for sustainable development is how societies are to avoid, minimize or address impacts from anthropogenic climate change. However, competing perspectives on...     

基于数据挖掘分析针刺治疗突发性耳聋的选穴规律

目的：通过数据挖掘技术分析针刺治疗突发性耳聋的选穴规律。方法：检索2013年1月1日至2022年10月20日中国知网（CNKI）和维普中文科技期刊数据库（VIP）中针刺治疗突发性耳聋的临床文献,按纳入和排除标准筛选文献并提取腧穴处方,采用Excel统计腧穴频次,使用IBM SPSS Statistics 23.0、SPSS Modeler 18.0软件进行关联性分析。结果：纳入63篇文献,共计63首穴位处方。使用频次排前5位的穴位依次是听会、翳风、听宫、耳门、中渚;最常选取的经脉为手少阳三焦经、足少阳胆经和手太阳小肠经;使用频率排前3位的特定穴是交会穴、五输穴和八脉交会穴;腧穴分布情况主要以头颈部腧穴为主,其次是下肢与上肢的腧穴。关联性分析结果提示,核心腧穴处方为翳风-外关-听宫-听会-中渚-耳门,核心穴对是翳风-外关-听宫。结论：针刺治疗突发性耳聋以核心穴组为基础,兼顾祛风、活血、补肾及醒脑开窍,临床应结合经络配穴及辨证取穴。     

地震资料中柱状流体运移通道形态参数及其地质意义

深部流体在向上运移的过程中,能够形成垂直-近似垂直的柱状通道,如气烟囱构造、流体逸散管道等。利用高分辨率地震资料,能够直观地对这些柱状地球物理异常进行精细的描述与刻画,从而统计其形态参数。综合不同海域的研究成果,本次研究系统总结归纳了柱状流体运移通道的8个重要参数,分别是发育层位、终止层位、平面形状、直径、高度和宽高比、反射偏移、椭圆率、拟合椭圆方位角。形态参数分别与通道群在平面上的展布方位、特殊的海底异常地貌(如海底麻坑、丘状体等)、深部构造发育与分布(如底辟、断层等)等进行耦合关联,能够进一步揭示柱状流体运移通道的地质含义。可将形态参数分为:(1)从形态学上对柱状通道进行直接分类的参数;(2)指示柱状通道形成诱发因素或形成过程的参数;(3)划分柱状通道幕式流体活动及期次的参数;(4)定义柱状通道中流体活动时间区间的参数;(5)间接反映柱状通道中流体通量相对大小的参数。实际研究过程中,单一形态参数难以准确反映出复杂地质背景下柱状通道的真实地质含义,多参数组合、相互对比验证,能够更好地对柱状流体通道的地质含义做出综合分析。     

Temporal and spatial dynamics in aquatic macroinvertebrate communities along a small urban stream

Urbanization is a current and increasing threat to biodiversity. The effects of urbanization on the functional and taxonomic composition of macroinvertebrate assemblages were investigated in two seasons along a small urban stream. Species composition was determined by the rate of urbanization; however, response of species richness could not be evidenced. Relative abundance of the sensitive macroinvertebrate groups (EPT%) was negatively related to urbanization. Almost all feeding groups showed a sharp decline in the number of specimens along the increase of urbanization. The study supports the view that urbanization has a negative effect on the biological quality of a stream, yet, this obvious impact can be overridden by different measures such as modification in streambed morphology. The altered conditions and new circumstances in urban environments lead to the creation of novel ecosystems, inhabited by macroinvertebrate communities with species richness approaching that of low impacted sites. However, species composition of these communities could be basically different from that of the natural ones.     

Thermal and magnetically driven instabilities in a non-constantly stratified fluid layer

Abstract

The linear hydromagnetic stability of a non-constantly stratified horizontal fluid layer permeated by an azimuthal non-homogeneous magnetic field is investigated for various widths of the stably stratified part of the layer in the geophysical limit q→0 (q is the ratio of thermal and magnetic diffusivities). The choice of the strength of the magnetic field B_o is as in Soward (1979) (see also Soward and Skinner, 1988) and the equations for the disturbances are treated as in Fearn and Proctor (1983). It was found that convection is developed in the whole layer regardless of the width of its stably stratified part. The thermal instability penetrates essentially from the unstably stratified part of the layer into the stably stratified part for A ～ 1 (A characterises the ratio of the Lorentz and Coriolis forces). When the magnetic field is strong (A>1) the thermal convection is suppressed in the stably stratified part of the layer. However, in this case, it is replaced by the magnetically driven instability; which is fully developed in the whole layer. The thermal instabilities always propagate westward and exist for all the modes m. The magnetically driven instabilities propagate either westward or eastward according to the width of the stably and unstably stratified parts and exist only for the mode m=1.     

关于甘肃长城纪地层划分的新认识

甘肃的长城纪地层划分以岩石地层为主。地层区可划分为北山地层区、祁连—北秦岭地层区（包括祁连山西段分区和兰州—天水分区）、华北地层区陇东分区及扬子地层区摩天岭分区。甘肃省长城纪岩石地层共分为７个群级单位（铅炉子沟群、古硐井群、朱龙关群、托来南山群、兴隆山群、碧口岩群、贺兰山群）、７个组级单位（熬油沟组、桦树沟组、南白水河组、葫芦河组、阳坝岩组、秧田坝岩组、黄旗口组）和６个组级非正式岩石地层单位。各单位特征明显，反映了甘肃省长城纪古地理轮廓和地层格架面貌