EUROPEAN SPACE AGENCY: New Science Chief Must Juggle Missions and Politics

With calls to tie the European Space Agency (ESA) more closely to the business and security sectors (see sidebar), space scientists hope David Southwood, who will take over next May as ESA's science director, can nurture the agency's research with the skill he showed transforming its earth sciences division. Experts say he's up to the task.     

基于SAR波模式数据的沉船事故海浪要素分析

涌浪是近海波浪系统中的重要组成部分,因其持续时间长且蕴含巨大能量,可导致渔船沉没事故,造成生命、财产和环境危害。合成孔径雷达(SAR)能够对海浪成像并提供二维方向谱,成为遥感海浪的重要手段。本研究将利用欧空局环境卫星搭载的高级合成孔径雷达(ENVISAT-ASAR)的波模式轨道数据提供的涌浪信息,量化涌浪在中国近海浪致渔船沉没事故中的影响。首先,对浪致渔船沉没事故、ASAR数据和模式数据进行时空匹配;其次,对匹配成功的数据进行对比统计,分析涌浪要素特征,量化涌浪影响。结论:渔船沉没事故发生时,(1)天气形势多为冷空气、温带气旋或台风;(2)风浪、涌浪混合有效波高绝大部分大于2.0 m,涌浪波高占比在50%以上;(3)风浪和涌浪夹角45°,当同时满足(2)和(3)条件时更容易发生沉船事故。     

弓形虫ES抗原激活免疫细胞的作用

12只经弓形虫 IHA检测为阴性的山羊 ,ESA和 TLA分别免疫 2次 ,用强毒虫株攻虫 ,进行体温测定 ,在整个试验期内检测了外周血免疫细胞的变化。结果发现 ,外周血白细胞总数攻虫后下降 ;淋巴细胞攻虫后百分率上升 ,ESA组显著地高于 TLA组 ;用 ESA和 TLA免疫可诱导嗜酸性粒细胞出现及迟发性超敏反应的发生 ;ESA免疫可使 T细胞数增加 ,使 T细胞的活性增强 ;攻虫的结果表明 ,ESA免疫获得了对接种感染的免疫。     

Sensitivity of leaf chlorophyll empirical estimators obtained at Sentinel-2 spectral resolution for different canopy structures

A comparison of the sensitivity of canopy scale estimators of leaf chlorophyll, obtainable with Sentinel-2 spectral resolution, to soil, canopy and leaf mesophyll factors, was addressed. The analysis of a synthetic dataset, generated simulating the reflectance in the 1–4 LAI range of canopies for the main general classes of leaf inclination (i.e. erectophile, plagiophile, spherical, planophile and extremophile) and for different soil types was used for such a purpose. The synthetic dataset was obtained using the PROSPECT5-4SAIL model in the direct mode with a large variety of soil backgrounds. Additionally an experimental dataset including airborne hyperspectral data gathered during ESA (European Space Agency) campaigns SPARC and AGRISAR, was employed to simulate Sentinel-2 spectral and spatial resolution, to confirm model results. Analysis of the synthetic and experimental datasets indicated that: (i) the CVI (Chlorophyll Vegetation Index), relying only on visible and NIR (Near Infra-Red) bands and obtainable at 10 m spatial resolution, can be used as leaf chlorophyll estimator, at growth stages suitable for nitrogen fertilizer topdressings, for all canopy structures except for erectophile canopies; (ii) better results can be obtained by using different indices for different leaf architectures, with TCI/OSAVI (Triangular Chlorophyll Index/Optimized Soil Adjusted Vegetation Index) performing better for erectophile canopies, whereas MTCI (MERIS Terrestrial Chlorophyll Index) provides better results for planophile canopies, despite the fact that these indices require bands obtainable at 20 m spatial resolution from Sentinel-2 data.     

Cassini Imaging Science: initial results on Saturn's atmosphere

The Cassini Imaging Science Subsystem (ISS) began observing Saturn in early February 2004. From analysis of cloud motions through early October 2004, we report vertical wind shear in Saturn's equatorial jet and a maximum wind speed of approximately 375 meters per second, a value that differs from both Hubble Space Telescope and Voyager values. We also report a particularly active narrow southern mid-latitude region in which dark ovals are observed both to merge with each other and to arise from the eruptions of large, bright storms. Bright storm eruptions are correlated with Saturn's electrostatic discharges, which are thought to originate from lightning.     

Two-way laser link over interplanetary distance

Here we report timed observations with subnanosecond precision of short laser pulses at a distance of nearly 24 million kilometers between the Mercury Laser Altimeter (MLA) aboard the MESSENGER (MErcury Surface, Space ENvironment, GEochemistry, and Ranging) spacecraft and the NASA Goddard Geophysical and Astronomical Observatory (GGAO). Forty MLA downlink observations and 90 uplink observations were obtained during observing sessions on 27 and 31 May 2005. Precise standard ground timing allowed a solution for spacecraft range, range rate, and acceleration, as well as clock bias. This experiment established a new distance record for laser detection and accomplished a two-way laser link at an interplanetary distance.     

Corrections and clarifications

In the report "The drift of Saturn's north polar spot observed by the Hubble Space Telescope" by J. Caldwell et al. (16 Apr., p. 326), the revised System III rotation rate of the drift was incorrectly calculated. It should not have been "810.737 degrees +/- 0.008 degrees per day," as stated (line 21, col. 1, p. 329), but rather "810.851 degrees +/-0.008 degrees per day."     

Magnetic field studies at jupiter by voyager 1: preliminary results

Results obtained by the Goddard Space Flight Center magnetometers on Voyager 1 are described. These results concern the large-scale configuration of the Jovian bow shock and magnetopause, and the magnetic field in both the inner and outer magnetosphere. There is evidence that a magnetic tail extending away from the planet on the nightside is formed by the solar wind-Jovian field interaction. This is much like Earth's magnetosphere but is a new configuration for Jupiter's magnetosphere not previously considered from earlier Pioneer data. We report on the analysis and interpretation of magnetic field perturbations associated with intense electrical currents (approximately 5 x 10(6) amperes) flowing near or in the magnetic flux tube linking Jupiter with the satellite Jo and induced by the relative motion between Io and the corotating Jovian magnetosphere. These currents may be an important source of heating the ionosphere and interior of Io through Joule dissipation.     

天津滨海新区夏季街旁绿地使用者游憩行为研究

从使用者的角度,采用行为观察法对滨海新区夏季街旁绿地使用者游憩行为进行调查,并进行分析。结果表明:使用者的活动内容随时间产生规律性的变化;老年人是绿地的使用主体;男性使用者多于女性;体育健身类、静态休闲类、文化娱乐类活动是主要的休闲娱乐方式;使用者数量峰值出现在一天中的10:00时和16:00时;由于体育健身类、静态休闲类是主要的休闲娱乐方式,使用率最高的地方是有健身器材的广场以及遮阴效果较好的长廊。     

Discovery of powerful gamma-ray flares from the Crab Nebula

The well-known Crab Nebula is at the center of the SN1054 supernova remnant. It consists of a rotationally powered pulsar interacting with a surrounding nebula through a relativistic particle wind. The emissions originating from the pulsar and nebula have been considered to be essentially stable. Here, we report the detection of strong gamma-ray (100 mega-electron volts to 10 giga-electron volts) flares observed by the AGILE satellite in September 2010 and October 2007. In both cases, the total gamma-ray flux increased by a factor of three compared with the non-flaring flux. The flare luminosity and short time scale favor an origin near the pulsar, and we discuss Chandra Observatory x-ray and Hubble Space Telescope optical follow-up observations of the nebula. Our observations challenge standard models of nebular emission and require power-law acceleration by shock-driven plasma wave turbulence within an approximately 1-day time scale.     

International sun-Earth explorer: a three-spacecraft program

The International Sun-Earth Explorer is a three-spacecraft program of the National Aeronautics and Space Administration and the European Space Agency aimed at securing a more quantitative knowledge of the structure and stability of the magnetosphere. One spacecraft (ISEE-C) makes observations in the solar wind upstream of the earth, while the other two (ISEE-A and ISEE-B), in the same highly eccentric orbit but separated by a relatively small variable distance, observe inside the magnetosphere. This international program is concurrent with the International Magnetospheric Study, to which ISEE-A and ISEE-C form a large U.S. contribution. The scientific aims and technological methods are discussed.     

航天搭载对玉米自交系SP_1的诱变效应

航天诱变是创造变异的有效手段,通过卫星搭载3个玉米自交系干种子,研究其诱变当代(SP1)主要性状的诱变效应。结果表明,航天辐射处理畸变率增大,生育期不同程度延长,主要株型性状表现出不同程度的抑制作用,而成苗率和成株率、主要雄穗性状和果穗性状等差异较大,表现既有促进作用也有抑制作用;SP1群体内各性状的变幅和变异系数均大于对照,表明航天搭载能创造丰富的变异,而其是否为遗传性变异有待进一步验证。     

SPACE SCIENCE: Europe Set to Work on Hubble's Replacement

NASA scientists and engineers working on the Next Generation Space Telescope (NGST) got a boost from across the Atlantic last week. On 15 September in Paris, the European Space Agency's top science advisory committee recommended that the agency become a major partner in the project. The recommendation puts NGST--along with a handful of other missions the committee also endorsed last week--one short step away from officially becoming part of Europe's space program.     

Erratum

In the article "Space station price climbs higher" by Eliot Marshall (News & Comment, 17 July, p. 242), Herbert Friedman, a member of the National Research Council panel studying the space station, was incorrectly identified as a former presidential economic adviser. He is emeritus scientist, Naval Research Laboratory and Martin Marietta Fellow of the National Air and Space Museum.     

Astronomers meet in phoenix, recount a stellar year

Despite a tightening of the National Aeronautics and Space Administration's budget and the trouble with the Hubble Space Telescope, astronomers were starry-eyed over their latest findings, presented at the major annual meeting of the American Astronomical Society, (AAS) January 3 to 7. New images and measurements of stars, galaxies, cosmic microwaves, and mysterious gamma rays, along with an exciting nova explosion, made it a bright year for those working with existing orbiting satellites and ground-based telescopes, though uncertain funding clouds the future.     

Predators, prey, and natural disasters attract ecologists

Some 2200 ecologists turned out for the 78th annual meeting of the Ecological Society of America (ESA), held in Madison, Wisconsin, 31 July to 4 August. Among the offerings: reports on the effect of dams and levees on large river ecology, predator-prey interactions, how parasites might control evolution, and the impact of clearcutting on soil organisms.     

我国农村居民消费行为的实验研究

为深入研究我国农村居民的消费行为,揭示我国农村居民消费的行为特征及变化趋势,探讨增加农村居民收入、拓展农村消费的政策作用机制。采用经济计量学的研究方法,分别基于一元线性系统和一元非线性系统,构建我国农村居民消费行为的状态空间模型(State Space Model),并基于模型对相关时变参数进行卡尔曼滤波(Kalman filter)估计,详细地分析了我国农村居民1978—2010年间平均消费倾向(APC)和边际消费倾向(MPC)的变动趋势及相互关系;同时,对模型作了序列相关性检验、异方差检验和协整检验,以确保模型的合理性和有效性。通过对状态空间模型时变参数的估计,详细分析了我国农村居民消费行为的静态特征和动态特征及其相互关系,较好地解释了外部环境和内在动机对我国农村居民消费行为的影响机制。研究表明:我国农村居民消费行为的状态空间模型是合理的、有效的;农村居民消费行为表现为消费心理预期波动上行,消费倾向偏离趋于缩小,符合我国农村社会经济发展的客观现实。     

小城镇绿地系统规划探析——以盐城市义丰镇为例

该研究以义丰镇绿地系统规划为例,分析快速城市化背景下小城镇绿地系统的特点和规划原则。提出构建稳定镇域大环境生态绿地格局、发展森林式绿地、体现地域文脉及实现多功能复合的小城镇绿地系统的规划思路。     

甘肃天水航天育种示范区建设的途径

论述了近10年来中国西部航天(太空)育种基地取得的主要成就和存在的问题,并提出了甘肃天水航天育种示范区建设的基本思路和建设重点。     

公共图书馆打造“第三文化空间”的理论与实践

随着移动互联网技术发展和人们生活消费习惯的改变,图书馆主要服务工作受到了巨大冲击,图书馆消亡论一度盛行。随着“第三空间”理念与应用的兴起,图书馆作为场所、空间的价值正日益突显,彰显了其强大的生命力。文章结合“第三空间”的一般属性和图书馆作为获取与利用知识的文化场所的特殊属性,探讨基于空间视野下的图书馆专属的文化品牌的建立,将其建成文献资源服务基地、幼儿早期阅读推广基地、读者分享阅读心得与社交的基地、终身学习的基地,成为居民闲暇时爱去的“第三文化空间”。