Holography

Research on holography has now grown to such dimensions that we have not been able to mention each of the numerous authors who have made significant contributions to it. Investigators from Bell Telephone Laboratories, the RCA, Xerox, and Westinghouse laboratories, Conductron Corporation, GC-Optronics, IBM, TRW Systems, the University of Michigan, and Stanford University have made particularly significant early contributions in the United States. Especially notable were the efforts of R. J. Collier, L. Lin, K. S. Pennington, D. Ansley, L. Siebert, R. M. Grant, A. Lohmann, R. F. Wuerker, K. Stetson, R. Powell, J. Goodman, and their co-workers, in addition to those already mentioned, among many others. Early work in many parts of the world also includes that in France by S. Lowenthal, G. Nomarski, and J. Viepsilonnot; in Germany by H. Nassenstein; in Great Britain by J. M. Burch; in Japan by J. Tsujiuchi and T. Tsuruta; and in the Soviet Union by Yu. Y. N. Denisyuk, I. Nalimov, and L. M. Soroko. For a fuller account of these developments, see (42) and other references.     

Ecology. Tropical forest diversity--the plot thickens

Also see the archival list of Science's Compass: Enhanced Perspectives ECOLOGY:Enhanced: Tropical Forest Diversity--The Plot Thickens David F. R. P. Burslem, Nancy C. Garwood, Sean C. Thomas Ecologists have long pondered why tropical forests contain such a huge number of species and what factors might be responsible for maintaining this diversity. In a Perspective, Burslem and colleagues discuss unique data sets from the forest dynamics plots (FDP) network, which shed light on the factors responsible for tropical forest diversity. D. F. R. P. Burslem is in the Department of Plant and Soil Science, University of Aberdeen, Aberdeen AB24 3UU, UK. E-mail: d.burslem@abdn.ac.uk. N. C. Garwood is in the Department of Botany, Natural History Museum, London SW7 5BD, UK. E-mail: ncg@nhm.ac.uk. S. C. Thomas is in the Faculty of Forestry, University of Toronto, Toronto M5S 3B3, Canada. E-mail: sc.thomas@utoronto.ca     

Planetary radio astronomy observations from voyager 2 near jupiter

The Voyager 2 Planetary Radio Astronomy experiment to Jupiter has confirmed and extended to higher zenomagnetic latitudes results from the identical experiment carried by Voyager 1. The kilometric emissions discovered by Voyager 1 often extended to 1 megahertz or higher on Voyager 2 and often consisted of negatively or, less frequently, positively drifting narrowband bursts. On the basis of tentative identification of plasma wave emissions similar to those detected by Voyager 1, the plasma torus associated with Io appeared somewhat denser to Voyager 2 than it did to Voyager 1. We report here on quasiperiodic sinusoidal or impulsive bursts in the broadcast band range of wavelengths (800 to 1800 kilohertz). A Faraday effect appears at decametric frequencies, which probably results from propagation of the radiation near its sources on Jupiter. Finally, we discuss the occurrence of decametric emission in homologous arc families.     

拟茎点霉属的新种和新纪录

本文报导了拟茎点霉属（Phomopsis)的4个新种及3个国内新纪录，新种是寄生于肉桂和锡兰肉桂的樟拟茎点霉（P.cinnamoni sp.nov.)，寄生于泰国大枫子的大枫子拟茎点霉（P.hydnccarpi sp.nov.)寄生于胖大海的苹婆拟茎点霉（P.sterculioe sp.nov.)及寄生于龙眼和荔枝的龙眼拟茎霉（P.longanoe sp.nov.)新纪录是可拉拟茎点霉（P.colaoe Bond.-Mont.),薯蓣拟茎点霉（P.dioscoreoe sacc.)及棕榈拟茎点霉槟榔生理型（P.polmicola(Wint.)sacc.f.arecoe Sacc.)。     

Erratum

In the 21 December response by Bruce N. Ames and Lois S. Gold (Letters, p. 1645) to the letter by Frederica P. Perera (p. 1644), the last sentence of the third paragraph in column three should have read, "Both natural arsenic in water and natural radon in indoor air are present at high levels at some locations and were long neglected, while major efforts were put into miniscule amounts of industrial pollutants." In the 4 January response by Bruce N. Ames and Lois S. Gold (Letters, p. 12) to the letter by David P. Rall (p. 10), reference 11 should have read, "D. G. Hoel, J. K. Haseman, M. D. Hogan, J. Huff, E. E. McConnell, Carcinogenesis 9, 2045 (1988)"; reference 14 should have read, "E. Marshall, Science 250, 900 (1990); R. Doll, Eur. J. Cancer 26, 500 (1990); C. Hill, E. Benhamm, F. Doyon, Lancet 336, 1262 (1990); S. Freni, ibid., p. 1263."     

Growth fundamentalism in dying rural towns:Implications for rural development practitioners

In our paper we will try to connect the dynamics of community decline to individual responses. We will operate on two levels of reality. At the first level we will discuss the circumstances surrounding the recent decline of small communities in North Dakota. At the second level we will discuss how this decline affects small town residents' attitudes toward economic development. In the first level analysis we examine the thesis that the natural environment of community growth is economic exploitation; therefore, the decline of resource-based communities is natural and inevitable. We discuss the circumstances surrounding the recent decline of small communities in North Dakota. At the second level analysis, we operate at the level at which life circumstances and environments are shaped by political-economic institutions that in turn shape the behavior and mentality of communities, families, and individuals. We hypothesize that residents of declining small towns deny their powerlessness and adapt to their situation through intense dedication to economic growth. We develop a series of hypotheses to test this thesis using data from the North Dakota Rural Life Poll. In our conclusion, we discuss implications for rural development practitioners working in declining small towns where this intense dedication to economic development in prevalent.Dr. Stofferahn is an assistant professor in the Department of Sociology and director of the Social Science Research Institute at the University of North Dakota. He received his Ph.D. and M.S. in rural sociology from Iowa State University. Prior to coming to the University of North Dakota, Dr. Stofferahn was employed by the North Dakota Economic Development Commission. Mr. Fontaine received his M.S. in sociology from the University of North Dakota and is presently employed as the assistant director of the Social Science Research Institute. Douglas McDonald, Mike Spletto and Holly Jeanotte are graduate students in the Department of Sociology at the University of North Dakota. This paper originally was written as a class project in a graduate seminar in rural development.     

Correction

Due to a printer's error, a recent meeting of the Planetary Society in Washington, D.C., was incorrectly identified as a "Planetary Soviet" meeting in the News and Comment article by R. Jeffrey Smith, "A fresh start for arms control" (25 Jan., p. 389).     

Antagonistic Synergy: Process and Paradox in the Development of New Agricultural Antimicrobial Regulations

There is currently great controversy over the contribution antimicrobial use in animal agriculture has made to antimicrobial resistance in pathogenic bacteria with negative consequences for human health. In light of this, the approval process for antimicrobials used in US animal agriculture, known as New Animal Drug Application or NADA, is currently being revised by the federal government. We explore the public deliberations over the development of these new policies focusing our attention on the interaction between pharmaceutical companies and the U.S. Food and Drug Administration. What appears to be an antagonistic public discourse is examined in terms of its ability to simultaneously legitimate the roles of the Food and Drug Administration as the official arbiter of policy on antimicrobial use in animal agriculture and as a protector of the public welfare, as well as the role of pharmaceutical companies as the producers of safe and effective products necessary for the protection of public well-being. Wesley R. Dean is an Assistant Research Scientist in the Institute for Science, Technology and Public Policy at Texas A & M University. His PhD is in Sociology from the University of Alberta where he wrote a dissertation on the Canadian HIV-tainted blood scandal. He is currently engaged in research on USDA-CSREES National Integrated Food Safety Initiative, a project to systematically characterize antimicrobial decision-making in US animal agriculture. H. Morgan Scott earned a DVM from the University of Saskatchewan and a Ph.D. in Epidemiology from the University of Guelph. He is an assistant professor at Texas A&M University in the Department of Veterinary Integrative Biosciences. He is currently conducting epidemiological research on the transference of resistant genes from swine to human host populations and he is the principal investigator on the USDA-CSREES National Integrated Food Safety Initiative.     

苏州城区河道浮游植物功能群演替特征及其对环境因子的响应

苏州作为长江三角洲地区重要的城市之一,近年来其城区河道富营养化问题日趋严重。为探讨苏州城区河道浮游植物功能群的结构组成、周年演替以及其对环境因子的响应,于2018年对苏州城区河道进行每两月一次的调查分析。结果表明,全年共鉴定出浮游植物7门85属209种(包括变种和变型),可划分为29个功能群,其中19个(B、C、D、G、H1、J、Lo、M、MP、P、S1、S2、T、TC、W1、X1、X2、Y、Z)为该区的优势功能群。浮游植物功能群呈现出B+C+D+H1→W1+H1→P+G+H1→M+S1+H1的周年演替特征,功能群H1在全年占据绝对优势。RDA分析表明,水温、总氮、总磷和电导率是影响该水域浮游植物功能群变化的主要环境因子。     

Corrections and clarifications

In the authors' note for the report "Suppression of hyphal formation in Candida albicans by mutation of a STE12 homolog" by Haoping Liu et al. (9 Dec., p. 1723), the affiliation for G. R. Fink should have been the Whitehead Institute for Biomedical Research and the Massachusetts Institute of Technology, Cambridge, MA 02142, USA.     

甘蓝型油菜硫苷组分的双标图分析

采用GGE双标图法,对11份硫苷组分不同甘蓝型油菜进行4×7不完全双列杂交试验,旨在对各杂交组合的硫苷组分进行分析,从而筛选出其配合力较低的亲本组合来满足降低后代硫苷质量摩尔浓度的要求.结果显示:1对于2-羟-3-丁烯基而言,亲本一般配合力(GCA)较低的是父本D21R,D1R和母本D3AB,特殊配合力(SCA)较低的是父本91R,56R和母本D3AB,SCA较低的组合有S3×R3,S3×R7和S1×R3等;2对于3-丁烯基而言,亲本GCA较低的是父本15R,91R和母本Gd1AB,D3AB,SCA较低的是父本D1R,D21R和母本D3AB,SCA较低的组合有S3×R3,S3×R7和S1×R7等;3对父本GCA而言,3-丁烯基、4-羟-3-吲哚甲基、苯乙基、4-戊烯基与2-羟-3-丁烯基呈正相关,苯乙基、4-戊烯基与4-羟-3-吲哚甲基呈负相关.对母本GCA而言,3-丁烯基、4-戊烯基与2-羟-3-丁烯基呈正相关,苯乙基、4-羟-3-吲哚甲基与2-羟-3-丁烯基呈负相关;4各杂交组合硫苷组分的表型关系中,亲本针对各组分GCA的相关性与母本配合力效应双标图中所显示出来的结果基本一致.利用GGE双标图分析表明,选用D3AB作母本、D21R及D1R作为父本有利于降低杂种后代油菜籽中硫代葡糖苷的质量摩尔浓度.     

番石榴上的一种新病原菌

1988年至1990年间,作者在广州地区调查番石榴病害过程中发现一种病害,由真菌新种He(?)P(?)sp.nov.引起的,为害果实引起腐烂,文中进行了形态学描述,模式标本存华南农业大学植保系。     

Once and future farming: Some meditations on the historical and cultural roots of sustainable agriculture in the United States

American agricultural history, literature, and thought reveal historical circumstances that have often been unfavorable to the development of a sustainable agriculture in the United States. Further critical examination of these historical and cultural roots reveals that sustainable agriculture is an evolving concept that can be traced to the tradition of agrarian idealism, scientific and organic agriculture, and the recent history of ecological ideas, beginning with the Dust Bowl and extending to the present.Carl D. Esbjornson received his Ph. D. in English, with an emphasis in American literature and culture, from the University of Iowa. He taught at the University of Iowa, Oklahoma State University, the University of South Dakota, and, for the last four years, as an assistant professor in the Department of American Thought and Language at Michigan State University. He has published articles on Wendell Berry and on recent American poetry. He is now engaged in a more extended interdisciplinary study of sustainable agriculture. He now lives in Minnesota, working as an independent scholar, free-lance writer, and an advocate for sustainable agriculture.     

基因频率随机过程模型的形成与发展

基因频率变化规律是群体遗传学研究的核心,也是理解生物进化的关键。近１个世纪以来,许多遗传学家做出了重要贡献。在许多遗传学著作中,常常提到基因频率的Ｈａｒｄｙ－Ｗｅｉｎｂｅｒｇ平衡定理,并把此定理作为群体遗传学的核心,不适当地夸大了这个定理的作用。而真正对群体遗传学的基本理论,特别是群体遗传学数学理论有开拓性贡献的遗传学家,当属Ｒ．Ａ．Ｆｉｓｈｅｒ,Ｓ．Ｗｒｉｇｈｔ,Ｊ．Ｂ．ＳＨａｌｄａｎｅ,Ｔ．Ｄ     

Erratum

In the report "Stimulation of heterotrophic microplankton production by resuspended marine sediments" by Sam C. Wainright (18 Dec., p. 1710), two articles should not have been included in reference 2. These are G. T. Rowe, C. H. Clifford, K. L. Smith, Jr., P. L. Hamilton, Nature (London) 255, 215 (1975) and S. W. Nixon, C. A. Oviatt, S. S. Hale, in The Role of Terrestrial and Aquatic Organisms in Decomposition Processes, J. M. Anderson and A. MacFadyen, Eds. (Black-well, Oxford, England, 1976), pp. 269-283.     

2011~2016年广西罗非鱼源无乳链球菌的耐药谱型分析

[目的]了解广西罗非鱼源无乳链球菌耐药谱的变迁规律,为罗非鱼无乳链球菌病的有效防控和科学用药提供参考.[方法]采用K-B纸片扩散法对分离自广西南宁、玉林、柳州、河池、北海和百色等市养殖患病罗非鱼的48株无乳链球菌株进行抗生素耐药性分析;并以抗生素的抑菌圈直径为变量,采用SPSS 18.0对无乳链球菌株进行聚类分析,以平方Euclidean距离表示菌株间的耐药性同类关系.[结果]48株广西罗非鱼源无乳链球菌的耐药谱型共有19种,谱型丰富度为39.6%.所有耐药谱型均为多重耐药谱型,耐药种数至少有3种.从采样地点来看,南宁市、玉林市、柳州市、河池市、北海市和百色市的分离株分别包含5、9、8、2、1和2种耐药谱型.2011~2016年各年份的菌株耐药谱型为:2011年10种(A、B、F、J、K、N、O、P、Q和S耐药谱型),2012年4种(B、H、N和S耐药谱型),2013年2种(L和M耐药谱型),2014年3种(B、D和S耐药谱型),2015年9种(B、C、D、E、G、H、J、R和S耐药谱型),2016年3种(B、I和J耐药谱型).聚类分析将48株广西罗非鱼源无乳链球菌分成2个组群(Group I和Group II)和6个亚群(i~vi),其中Group I和Group II组群均含有11种耐药谱型,耐药谱型丰富度分别为37.9%和57.9%;Group I和Group II两组群无乳链球菌株的抗生素敏感性差异主要取决于其对恩诺沙星、氟苯尼考和环丙沙星的敏感率或耐药率.[结论]2011~2016年广西罗非鱼源无乳链球菌的耐药谱型呈多样性,谱型丰富度较高,且因来源地不同和年际变化存在一定差异性.此外,通过聚类分析可根据无乳链球菌的耐药情况对其进行有效分型,建议作为无乳链球菌流行病学分型方法给予推广应用.     

ESSAYS ON SCIENCE AND SOCIETY: In Search of Einstein's Genius

Steve C. Wang is a lecturer in the Department of Statistics at Harvard University. He earned his B.S. from Cornell University and his Ph.D. in statistics from the University of Chicago. He has taught statistics and mathematics at the University of Chicago and Williams College. His research interests include applying statistics to paleobiology, endocrine diseases, and image recognition.     

梭鱼草对铜胁迫的光合适应性

以液培方法研究了不同质量浓度(0、5、10、20 mg·L-1)铜离子(Cu 2+)对梭鱼草叶片光合色素、气体交换参数和叶绿素荧光参数的影响,以探究梭鱼草对Cu 2+的光合适应能力。结果显示:低质量浓度Cu 2+对梭鱼草叶片光合色素质量分数没有显著影响,而较高质量浓度Cu 2+(≥10 mg·L-1)导致光合色素质量分数显著下降;随着溶液中Cu 2+质量浓度的升高,梭鱼草叶片净光合速率(P n)、蒸腾速率(E)、气孔导度(G s)和水分利用率(W U,E)显著下降,叶片饱和蒸气压亏缺(V P,D)增加,而饱间CO 2摩尔分数(C i)和气孔限制值(L s)无明显变化;在最高质量浓度Cu 2+处理条件下,梭鱼草叶片叶绿素最大荧光(F m)、可变荧光产量(F v)、PSⅡ潜在光合活性(F v/F o)、PSⅡ最大光化学效率(F v/F m)、单位面积电子传递的量子产额(E T,o/C S,o)及光合性能指数(P I,a,b,s)显著下降,反应中心净关闭速率(d V,G/d t,o和d V/d t,o)、比活性参数A B,S/R C、T R,o/R C、D I,o/R C及单位面积耗散掉的能量(D I,o/C S,o)则呈相反的变化趋势。梭鱼草叶片对5 mg·L-1 Cu 2+表现出较好的光合适应能力。随Cu 2+质量浓度升高,非气孔因素是梭鱼草叶片P n下降的主要原因。较高质量浓度Cu 2+处理下,梭鱼草叶片光合机构可以通过关闭部分反应中心、增加热耗散等途径缓解过量Cu 2+对光合机构的破坏。     

鹅掌藤真菌病害的鉴定

 报道了为害广州地区鹅掌藤（Schefflera arboricola Hayata）的6种病原真菌,即黑白拟茎点霉〔Phomopsis melaleuca （Berk.＆ M.A. Curtis）Grove〕,鹅掌柴叶点霉（Phyllosticta schefflerae P.G.Xi. P.K.Chi et Z.D.Jiang ),橄榄色盾壳霉（Coniothyrium olivaceum Bon.）,楤木球座菌（Guignardia araliae Gutner）,烟草疫霉寄生变种〔Phytophthora nicotianae var. parasitica （Dast.）Waterh．〕和胶孢刺盘孢〔Colletotrichum gloeosporioides (Penz.) Sacc. 〕,其中鹅掌柴叶点霉为新种,黑白拟茎点霉为国内新纪录种。在大棚生产中,以烟草疫霉引起的叶疫病和胶孢刺盘孢引起的炭疽病发生普遍而严重。模式标本保存在华南农业大学真菌标本室。     

偏肿革裥菌系统发育与Lg-mnp2和Lg-mnp3基因克隆及结构特征

白腐菌偏肿革裥菌Lenzites gibbosa能分泌降解木质素的锰过氧化物酶(MnPs),为进一步鉴定试验菌株,对菌株L. gibbosa CB1进行了ITS序列(Gen Bank登录号为JF279440)扩增与测序,并进行了基于ITS序列的比对与系统发育分析,结果表明CB1与桦革裥菌L. betulina和栓菌属Trametes等相关白腐菌的亲缘关系较近而聚类在一起,并与24个同种其他菌株的ITS序列覆盖度在85%～97%期间内的相似性都为99%,说明该菌株为偏肿革裥菌。为了获得该菌株多个编码MnP家族的基因,从而为研究MnP基因的表达调控奠定序列结构的基础,根据已知白腐菌MnPs基因保守区和已经扩增出的基因片段设计引物,以L. gibbosa CB1的基因组DNA和总RNA为模板,采用PCR、RT-PCR、RACE及染色体步移等方法,克隆到该菌株编码MnP2和MnP3的全长c DNA和DNA基因(Gen Bank登录号分别为JQ388597、JN571114; JQ411249、JN571116),分别命名为Lg-mnp2和Lg-mnp3。2个基因DNA全长分别为2 869、3 992 bp,都含有6个外显子和5个内含子;其启动子区域都含有TATA-Box、CAAT-Box、AP2、MRE等顺式作用元件,Lg-mnp2还含有AP1,Lg-mnp3还含有HSE;其c DNA基因分别含有50、52 bp的5'UTR,150、249 bp的3'UTR和1098、1 101 bp的完整开放阅读框ORF,分别编码了365、366个氨基酸的蛋白质多肽前体(Gen Bank登录号分别为AFC37493、AFC37494),成熟的Lg-mnp2蛋白含有339个氨基酸,比Lg-MnP1蛋白(Gen Bank登录号为ACO92620)多1个氨基酸;成熟的Lg-mnp3蛋白含有340个氨基酸,比Lg-MnP2蛋白多1个氨基酸。