用蚕豆根尖细胞微核技术监测湛河水质的研究

利用蚕豆根尖细胞微核试验检测湛河水体中是否存在致突变因子污染,在平顶山市区选取18个有代表性的采样点,采集各样点排出的废水作为水样。通过测定湛河各样点水样的微核千分率（MCN‰）以及污染指数（PI值）来判断污染程度,并F检验各水样的MCN‰的差异显著性。试验结果表明,各样点的MCN‰有显著性差异。湛河18个样点中水质属重度污染的有7点,占全部的38.9%,水质属中度污染的有6点,占全部监测点的33.3%。该实验表明湛河水质受到较严重的致突变性的污染。     

污水样微核率与COD值和BOD值的关系

利用蚕豆根尖细胞微核试验检测湛河水体中是否存在致突变因子污染,方法准确可靠,但工作量较大。针对固定的监测水体,利用微核率与COD值和BOD值的相关性,建立回归方程,便可用水样的COD值或BOD值来估计其微核率。沿湛河采集18个样点的污水作为水样测定其微核千分率（MCN‰）、COD值和BOD值,分析表明,CODMn和BOD与微核千分率的相关系数（r）分别为0．91和0．93,均存在极显著的相关关系,由此分别建立其回归方程为Y=0．0737XCOD＋3．2853,Y=0．161XBOD＋5．9622。     

北京市冬季大气颗粒物污染水平和影响因素研究

北京市大气颗粒物造成的城市空气污染仍是目前亟待解决的问题之一。为了分析北京市大气颗粒物的污染水平及其影响因素，作者以大气中的PM10 和PM2.5为研究对象，于2005年冬季在北京市范围内设立了5个功能区（9个采样点）进行采样监测。结果表明，北京市PM10 和PM2.5污染比较严重，不同区域的PM10 和PM2.5的污染程度为：交通干道区＞工业区，郊区＞商业区＞居民区，且PM2.5质量浓度的空间分布并不完全同于PM10；气象条件稳定时，PM10 和PM2.5质量浓度的日变化表现出一定的规律性，这种时间变化的特征主要取决于所在环境中排放的污染物变化情况；PM10 和PM2.5的污染程度受气象条件的影响：在一定的范围内，颗粒物质量浓度随着温度的上升而下降，随着相对湿度的升高而增加，随着风力的增强而降低，随逆温层的生成及增强而增高。     

铜对不同水稻品种种子萌发及根尖分生细胞钙分布的影响

以16个水稻品种为材料,测定了铜对水稻种子萌发相关指标,并观察了根尖有丝分裂及分生区Ca分布的影响。结果表明：（1）0．1mM和0．2mMCuSO4溶液处理对水稻根长的抑制作用大于对芽长的抑制,且对不同品种根长的抑制作用存在明显差异;（2）随着铜处理浓度（25、50、75、100μM）的升高,根尖细胞有丝分裂指数及相对有丝分裂指数皆呈下降趋势;（3）t常生长条件下,水稻根尖分生区细胞中的Ca主要分布在液泡和细胞间隙中,而细胞质、细胞核中分布很少;50μM铜处理下,根尖分生区细胞液泡和胞间的Ca沉淀颗粒明显减少,而胞质及核基质中的Ca沉淀颗粒增多。铜胁迫造成根尖细胞中原有Ca分布的变化可能是引起细胞功能的紊乱,进而影响根系生长的原因之一。     

长春市农业种植区重金属污染评价研究

土壤重金属污染不仅对城市环境有较大损害,还会通过农作物的吸收迁移威胁到人类身体健康。通过对该领域国内外研究现状及长春市农业种植区自然与人文条件的分析,以土壤及部分代表性农作物为研究对象,在研究区域内设置85个采样点,对格网布点法所选取的采样点进行重金属污染评价研究,探讨了长春市农业种植区重金属污染分布特征和污染程度,并提出相应防治措施。     

河流水体中溶解性有机物构成的三维荧光光谱解析

利用三维荧光技术研究了大石河6个采样点水体中溶解性有机物(DOM)的组成,并分析其荧光指数(FI)、生物源指数(BIX)、腐殖化指数(HIX)等定量指标特征。结果表明,大石河水体中以腐殖酸类物质和富里酸物质类为主。所有水样中的荧光指数都大于1.7,各点DOM来源属于陆源和内源混合,说明工业废水的排放,人类的生产活动产生大量污染物质的输入,加剧河流污染。     

西藏拉鲁湿地浮游植物污染指示种及水质评价

为了研究拉鲁湿地水体浮游植物污染指示种及其水质评价,于2021年7月在拉鲁湿地水域内设置了42个采样点,用25#浮游生物网采集水样210个,应用浮游植物污染指示种计算污染生物指数,通过保留或去除恒有种、常见种、偶见种和稀有种形成一个“新”群落,然后比较“新”群落污染生物指数与原群落污染生物指数对水质评价的影响。结果表明：（1）在拉鲁湿地水域共鉴定出浮游植物污染指示种148种（含变种）,隶属于7门9纲17目29科50属,其中含恒有种4种（属）,常见种23种（属）,偶见种24种属,稀有种97种（属）;（2）通过计算得出拉鲁湿地水域浮游植物污染生物指数（SI）平均值为1.958,说明拉鲁湿地水域水质为β-中污型;（3）保留恒有种、常见种、偶见种和稀有种平均污染生物指数分别为1.896、1.972、1.972和1.983或去除恒有种、常见种、偶见种和稀有种平均污染生物指数分别为2.227、1.918、1.749和1.619,故去除或保留恒有种、常见种、偶见种和稀有种对多数样点SI值的影响较小,对整体无明显影响,整体上仍属于β-中污型。此次研究结果可为拉鲁湿地水域水质评价提供科学参考依据。     

洁净室（区）悬浮粒子数计算方法的探讨

分析了在洁净室（区）空气中悬浮粒子的测试中,对同一个洁净室选取不同个采样点后,所得95％的置信上限（即UCL值）差异显著的原因,并以中心极限定理证明了由于采样点少而整体不服从正态分布的情况,从而提出了以洁净室中每个采样点几次采样的UCL值来判定其是否达到洁净级别的方法。     

18-26S rDNA在4种重楼属植物中的定位

为探讨rDNA在重楼属Paris L.中的分布规律，利用荧光原位杂交（FISH）对4种重楼属植物 的18-26S rDNA进行了定位。所有植物均为二倍体，基因组由A、B、C、D和 E5条染色体构成。（1）滇重楼P.polyphylla var.yunnanensis:2n=10=6m+4t，C和D染色体的 短臂上各有1个18-26S rDNA位点;（2）长柱重楼P.forrestii:2n=10=6m+4t，B染色体的长臂 、C和D染色体的短臂上各有1个位点;（3）五指莲P.axialis:2n=10=6m（2sat）+4t（2sat） +1-2B，C和D染色体的短臂上各有1个位点;在有1个B染色体的细胞中，B染色体没有信号点， 而有2个B染色体的细胞中，只有1个B染色体上有信号点，表明B染色体上有基因存在且其分裂 不均等;（4）大理重楼P.daliensis:2n=10=4m+2sm+2st+2t，C染色体的短臂上有1个位点。1 8-26S rDNA位点不仅出现在染色体的次缢痕上，也出现在非次缢痕位点。另外，4个种中C染 色体短臂末端均有18-26S rDNA。     

东江干流浮游植物的物种组成及多样性分析

基于2010年1月对东江干流水体51个点进行的浮游植物及其群落结构调查,研究了浮游植物的种类和密度状况,分析了河流中浮游植物群落的组成和生物多样性,并据此评价了东江干流水体水质污染状况.结果表明,该干流水体中物种丰富度中等,个体分布较均匀,共有浮游植物7门83种(包括2变种);其中硅藻门种类最多,达38种,占所有物种数的45.78％,其细胞生物量占总浮游植物的53.99％;主要优势种为卵形隐藻(Cryptomonas ovata)、变异直链藻(Melosira varians)、菱形藻(Nitzschia sp.)、小环藻(Cyclotella sp.)、舟形藻(Navicula sp.);浮游植物的密度分布不均匀,其中下游显著大于上、中游,且主要密集于下游的东莞市和惠州市江段水体;东江干流水体中浮游植物多样性指数相对较为一致,上游的物种多样性和种群结构稳定性较下游略高;以多样性指数为指标对水体作评价,结果显示大多数采样点位水体营养化程度不高,水质总体良好.     

Students' Reactions to the Introduction of Videoconferencing for Classroom Instruction

This study examined how students who had no prior experience with videoconferencing would react to the use of videoconferencing as an instructional medium. Students enrolled in seven different courses completed a questionnaire at the beginning of the semester and again at the end of the semester. Students at the origination and remote sites did not differ in their reactions toward videoconferencing but there was a significant difference for gender. Women reacted less favorably to videoconferencing. Compared to the beginning of the semester, students reported significantly less positive attitudes toward taking a course through videoconferencing at the end of the semester. There were no significant differences in students' attitudes toward videoconferencing across courses at the beginning of the semester but there were significant differences across the courses at the end of the semester. The results suggest the need for better preparation for both students and instructors.     

Cooler temperatures inductive to locust outbreaks

Ajoint study by Prof. ZHANG Zhibin from the CAS Institute of Zoology and his co-workers from Norway, US and Swiss have indicated that historical outbreaks of migratory locusts in China were associated with cold spells, suggesting that China＇s projected climate warming could decrease the pest＇s numbers. The study was published in Proceedings of theNational Academy of Sciences on 17 September, 2007.     

Exploring Multiplexity: Social Network Structures in a Computer-Supported Distance Learning Class

A computer-mediated group is a complex entity whose members exchange many types of information via multiple means of communication in pursuit of goals specific to their environment. Over time, they coordinate technical features of media with locally enacted use to achieve a viable working arrangement. To explore this complex interaction, a case study is presented of the social networks of interactions and media use among members of a class of computer-supported distance learners. Results show how group structures associated with project teams dominated who communicated with whom, about what, and via which media over the term, and how media came to occupy their own communication niches: Webboard for diffuse class-wide communication; Internet Relay Chat more to named others but still for general communication across the class; and e-mail primarily for intrateam communication. Face-to-face interaction, occurring only during a short on-campus session, appears to have had a catalytic effect on social and emotional exchanges. Results suggest the need to structure exchanges to balance class-wide sharing of ideas with subgroup interactions that facilitate project completion, and to provide media that support these two modes of interaction.     

The Role of Intermediating Institutions in the Diffusion of Electronic Data Interchange (EDI): How Industry Associations Intervened in Denmark, Finland, and Hong Kong

Electronic data interchange (EDI) provides means for interorganizational communication, creates network externalities, requires an advanced information technology (IT) infrastructure, and relies on standards. In the diffusion of such innovations, institutional involvement is imperative. Such institutions contain governmental agencies, national and global standardization organizations, local government, and nonprofit private organizations like industry associations. The last type of organizations we call intermediating institutions. They intermediate or coordinate ("inscribe") the activities of a group of would-be adopters. Unfortunately, little is known of how these organizations shape the EDI diffusion trajectory. In this article we examine one specific type of intermediating organizations?industry associations?and how they advanced the EDI diffusion process in the grocery sectors of Hong Kong, Denmark and Finland. We identify six institutional measures, placed into a matrix formed by the mode of involvement (influence vs. regulation) and the type of diffusion force (supply push vs. demand pull), that can be mobilized to further the EDI diffusion. Industry associations were found to be active users of all these measures to varying degrees. Their role was critical especially in knowledge building, knowledge deployment, and standard setting. Furthermore, institutional involvement varied due to policy and cultural contingencies and power dependencies.     

How Electronic Publishers are Protecting Against Piracy: Doubts About Technical Systems of Protection

The increasing prospects of digital piracy has prompted the perceived need by electronic publishers to adopt technical systems of protection, and governments to reform their copyright laws. This article is a preliminary study of the management of intellectual property by electronic publishers, defined as those involved in the production of online databases, and CD-ROMs. It focuses on three main issues: (1) how electronic publishers view the increasing threat of piracy; (2) the methods of protection employed to protect intellectual property in digital format; and (3) the importance of technological protection of intellectual property in electronic publications. The analysis is based on a sample of 23 UK electronic publishers. The interviews revealed an interesting assortment of protection methods and did not show that technological protection was a preferred way. Instead, the means of protection, in addition to copyright law, comprised niche markets, pricing, trust, bad publicity, and nontechnical and technical means.     

Rough Justice: A Statistical Assessment of ICANN's Uniform Dispute Resolution Policy

Long-standing conflict between domain name registrants and trademark holders prompted the Internet Corporation for Assigned Names and Numbers (ICANN) to create a global, mandatory arbitration procedure known as the Uniform Dispute Resolution Policy (UDRP). The UDRP has been used in 2166 cases involving 3938 domain names as of 1 November 2000. The policy gives the initiator of a complaint, generally a trademark holder, the right to choose which ICANN-accredited dispute resolution service provider (RSP) will handle the case. During the preparation of the UDRP,some feared that complainant selection would lead to "forum shopping" that might bias the results. This article performs a statistical assessment of the forum-shopping thesis and finds support for it. There are statistically significant differences in the various RSPs' propensity to take away names from defendants; there are also major differences in the number of cases brought to each RSP. RSPs who take away names have the larger share of cases. The study examines other variables that might explain differences in market share, such as price, the plaintiff's nationality, or the time taken to decide a case. It finds that nationality and time also are correlated with market share. The study concludes that shopping for a favorable outcome is an important factor in the UDRP.     

Prevalence of soft neurological signs in Chinese people

Prof. Raymond C.K. Chen, a neuropsychologist with the CAS Institute of Psychology, has made novel progress in his studies of schizophrenia. His work has been reported by a recent issue of Behavioural Neurology.     

Monoculture Rubber Plantations Have Negative Ef ects on Controlling Splash Erosion

<正>In Xishuangbanna,one of China’s most biodiverse regions,landscape has changed dramatically during the past three decades due to the conversion of tropical rainforest to rubber plantations.In steep areas,terraces are often constructed before planting rubber trees,which causes two important changes in the soil:the destabilization of soil in the bench terraces and the increased vulnerability of unvegetated riser faces to erosion.Few studies have documented the nature and intensity of erosion on bench terraces.Prof.LIU Wenjie and his colleagues from the Xishuangbanna Tropical Botanical Garden(XTBG)conducted a study in Menglun County(21°5′39″N,101°15′55″E),Xishuangbanna to evaluate the influence     

Chinese Scientists Use Earth Observation Technologies to Study and Protect Wild Camels

<正>Chinese scientists plan to apply Earth Observation technologies to protect the critically endangered wild camels(Camelus ferus).With the help of remote sensing,satellite positioning,geographical information system and wireless sensors networks,they will be able to access the distribution and population of the wild camels and protect their habitats.The project will be carried out by the International Research Center for Wild Camel Conservation,which was jointly established earlier this year by the Institute of Remote Sensing and Digital Earth(RADI)of the Chinese     

More than Skin Deep – Understand Skin Biology by Means of Dermatogenomics

<正>The Paul Gerson Unna Research Group on Dermatogenomics was founded in October 2012 at the Partner Institute for Computational Biology.The ultimate goal of the group is to understand the biology of skin and skin appendages.