Antiferromagnetism in Pressure-Amorphized Fe2SiO4

Amorphous Fe(2)SiO(4) synthesized at elevated pressures exhibits a Néel transition at a temperature identical to that observed in the crystalline form, T(N) = 65 (+/-2) kelvin at zero pressure. This behavior contrasts sharply with observations on other disordered systems, such as spin glasses, which characteristically exhibit strong "frustration" of the spins and consequent marked suppression of the Néel transition.     

板栗桃蛀螟有机防治技术研究

对北京市怀柔区板栗桃蛀螟的形态和危害特征、发生动态和大发生原因进行了调查,研究了板栗桃蛀螟的有机防治措施。结果表明,桃蛀螟在北京发生3代,第1代、第2代主要危害桃、杏、玉米,第3代转移到板栗危害,生物农药施安的防效与化学农药辛硫磷,可用于有机板栗生产;采用综合防治措施可以将板栗虫果率由20％～30％降低到4％以下。     

Erratum

In Albert B. Sabin's letter "Viral etiology of AIDS and the Gallo probe" (3 Aug., p. 465), reference 1 on page 466 should have read, "F. Barré-Sinoussi et al., Science 220, 868 (1983)."     

Physics/computer science. Passing messages between disciplines

Problems in computer science, such as error correction in information transfer and "satisfiability" in optimization, show phase transitions familiar from solid-state physics. In his Perspective, Mézard explains how recent advances in these three fields originate in similar "message passing" procedures. The exchange of elaborate messages between different variables and constraints, used in the study of phase transitions in physical systems, helps to make error correction and satisfiability codes more efficient.     

Mad cow disease. New recruits for French prion research

As panic over "mad cow disease" engulfs France and threatens to spread to other countries in Western Europe, French research minister Roger-Gérard Schwartzenberg last week unveiled detailed plans for spending $27 million the government has earmarked for prion disease research in 2001. Next year's budget for studying prions--infectious, abnormal proteins linked to bovine spongiform encephalopathy and its human form, variant Creutzfeldt-Jakob disease--will triple France's current prion research spending.     

European science. Bug Bastille to open under new management

In the next few weeks, Europe's most advanced high-security pathogen lab is expected to open for business in the southern French city of Lyons, but the long-anticipated debut of this "hot" lab is not turning out to be a joyous occasion for some of those involved. Last week, the Marcel Mérieux Foundation, which paid for the lab's construction, announced that the Pasteur Institute will take over its "scientific direction" and gave Pasteur the authority to name the lab's director. The leading candidate is a Pasteur scientist, which would leave the lab's current director out in the cold.     

Excitation of spirals and chiral symmetry breaking in rayleigh-benard convection

Spiral-defect populations in low-Prandtl number Rayleigh-Bénard convection with slow rotation about a vertical axis were measured in carbon dioxide at high pressure. The results indicate that spirals act like "thermally excited" defects and that the winding direction of a spiral is analogous to a magnetic spin. Rotation about a vertical axis, the spiral analog of the magnetic field, breaks the zero-rotation chiral symmetry between clockwise and counterclockwise spiral defects. Many properties of spiral-defect statistics are well described by an effective statistical-mechanical model.     

Chromospheric alfvenic waves strong enough to power the solar wind

Alfvén waves have been invoked as a possible mechanism for the heating of the Sun's outer atmosphere, or corona, to millions of degrees and for the acceleration of the solar wind to hundreds of kilometers per second. However, Alfvén waves of sufficient strength have not been unambiguously observed in the solar atmosphere. We used images of high temporal and spatial resolution obtained with the Solar Optical Telescope onboard the Japanese Hinode satellite to reveal that the chromosphere, the region sandwiched between the solar surface and the corona, is permeated by Alfvén waves with strong amplitudes on the order of 10 to 25 kilometers per second and periods of 100 to 500 seconds. Estimates of the energy flux carried by these waves and comparisons with advanced radiative magnetohydrodynamic simulations indicate that such Alfvén waves are energetic enough to accelerate the solar wind and possibly to heat the quiet corona.     

馆藏书目数据库中“异书同号”问题分析与对策

＂异书同号＂问题影响馆藏书目数据库的质量和读者检索和利用图书馆的效率。究其原因,图书编目过程中多种技术层面的不当操作直接导致馆藏图书的＂异书同号＂问题。采用计算机批量查找法和人工零星记录法查找出这些重复记录,并按步骤分析处理这些重复记录,并做好相应的预防措施,是处理＂异书同号＂、做好馆藏书目数据库维护的一个好方法。     

贵州省特有珍稀小檗属（小檗科）植物及其保护价值

为更好的掌握和保护贵州特有及珍稀植物资源,作者调查了贵州省小檗科小檗属特有植物7种,分别为二色小檗（Berberis bicolor H. Léveillé）、毕节小檗（B. guizhouensis T. S. Ying）、平坝小檗（B. pingbaensis M. T. An）、永思小檗（B. tsienii T. S. Ying）、威宁小檗（B. weiningensis T. S. Ying）、梵净小檗（B. xanthoclada C. K. Schneider）和紫云小檗（B. ziyunensis Hsiao & Z. Y. Li）,以及珍稀濒危植物1种,即二色小檗,该种被《中国物种红色名录》收录,建议优先保护;同时将粉叶小檗（B. pruinosa Franchet）和贵州小檗（B. cavaleriei H. Léveillé）移出贵州特有植物行列。文章描述了贵州小檗属特有和珍稀植物的保护价值及其分布产地,并整理出贵州省小檗科小檗属植物新名录（共44种1变种）,分析其目前存在的问题。     

资源植物玉叶金花挥发油的GC-MS分析及体外抗氧化活性研究

[目的]分析资源植物玉叶金花叶中挥发油的有效成分并评价其体外抗氧化活性。[方法]通过水蒸气蒸馏法提取玉叶金花叶中的挥发油,采用色谱-质谱联用(GC-MS)技术分析其化学组成。以VC作为对照,以总还原力和对超氧阴离子自由基、羟基自由基、DPPH自由基、ABTS自由基的清除能力为评价指标,研究玉叶金花挥发油的体外抗氧化活性。[结果]玉叶金花叶挥发油中共鉴定出49个有效成分,占其总量的68.19%,其中包括极具研究和应用价值的N-甲基吡咯(37.37%)和叶绿醇(7.34%)。且在试验浓度范围内,玉叶金花挥发油的总还原力以及对DPPH自由基、超氧阴离子自由基、羟基自由基、ABTS自由基的清除能力均随浓度的增大而增大。[结论]玉叶金花挥发油具有良好的体外抗氧化活性。     

杭州种子植物的一些新分布

2012~2013年,杭州植物园的调查人员在杭州西湖区发现马鞭草科的紫珠(Callicarpa bodinieri H.Léveillé),对比结果为杭州新记录种。另外,其他调查小组的人员在萧山和余杭也有所收获,发现15种种子植物属杭州萧山区和余杭区的新记录。     

性诱剂诱集稻纵卷叶螟效果试验

通过性诱剂诱捕稻纵卷叶螟的田间试验,比较3种诱捕测报工具的诱集效果,结果表明性诱剂的测报数据与其他2种测报手段基本吻合,对稻纵卷叶螟测报有一定的应用价值。     

Marine science and the 1974 law of the sea conference

More intensive and varied use of the oceans and their resources requires a more comprehensive legal reégime than previously. Three years of preparatory work have been completed leading toward the Law of the Sea Conference that opened on 20 June in Caracas, Venezuela. Although the details of the new reégime are still to be negotiated, it appears certain that the coastal nations will gain some form of jurisdiction over the fisheries and mineral resources off their shores. It is probable that a new "economic zone" will be established between a relatively narrow (12-mile) territorial sea and the international ocean space beyond. If, as seems likely, this economic zone is 200 miles wide, it will encompass some 37 percent of the ocean as shown in Fig. 1. Unless the scientific community can gather more support than it has to date, it seems probable that scientific research within this economic zone will only be possible with the consent of the coastal nation. The United States has proposed a compromise solution which attempts to balance the interests of the scientific community with those of the coastal state. Under the U.S. proposal, a research group abiding by certain specific obligations to the coastal state would be free to carry out its research activities without obtaining explicit consent from the coastal state. To date the U.S. proposal has received little official support from any nation, even from nations with major oceanographic interests.     

激素处理对昆明山海棠扦插生根的影响

[目的]研究适宜昆明山海棠[Tripterygium hypoglaucum(Lévl.)Hutchins]扦插繁殖的激素及其浓度。[方法]选用3种激素,分别为根旺、NAA和IBA,浓度均设计3个水平,分别为500、1 000、1 500 ml/L,以清水为对照。[结果]根旺、NAA和IBA对昆明山海棠插穗生根的影响是不同的。总体上,NAA对插穗生根的促进作用较明显,IBA和根旺的促进作用次之。其中IBA 1 500 ml/L对昆明山海棠插穗生根率、成活率、须根数的影响都明显高于其他处理,生根率达70%,比对照(2%)高68个百分点。其中对须根长促进作用最好的是NAA 500 ml/L。激素对插穗萌枝没有明显的促进作用。[结论]该研究可为昆明山海棠扦插繁殖提供参考。     

联系于实向量丛一对截面的P o i n c a r é - H o p f型公式

通过符号差Z2-分次将2n维Spin流形上关于复化切丛TMC截面的Poincaré-Hopf型公式推广到2n维非Spin流形上,并对于联系于定向实向量丛的一对截面建立了相应的Poincaré-Hopf型公式.     

Alfven waves in the solar corona

Alfvén waves, transverse incompressible magnetic oscillations, have been proposed as a possible mechanism to heat the Sun's corona to millions of degrees by transporting convective energy from the photosphere into the diffuse corona. We report the detection of Alfvén waves in intensity, line-of-sight velocity, and linear polarization images of the solar corona taken using the FeXIII 1074.7-nanometer coronal emission line with the Coronal Multi-Channel Polarimeter (CoMP) instrument at the National Solar Observatory, New Mexico. Ubiquitous upward propagating waves were seen, with phase speeds of 1 to 4 megameters per second and trajectories consistent with the direction of the magnetic field inferred from the linear polarization measurements. An estimate of the energy carried by the waves that we spatially resolved indicates that they are too weak to heat the solar corona; however, unresolved Alfvén waves may carry sufficient energy.     

Comment on "Lévy walks evolve through interaction between movement and environmental complexity"

de Jager et al. (Reports, 24 June 2011, p. 1551) concluded that mussels Lévy walk. We confronted a larger model set with these data and found that mussels do not Lévy walk: Their movement is best described by a composite Brownian walk. This shows how model selection based on an impoverished set of candidate models can lead to incorrect inferences.     

Shattuckite and plancheite: a crystal chemical study

The orthorhombic crystal structures of shattuckite, Cu(5)( SiO(3))(4)(OH)(2) and planchétite, Cu(8)(Si(4)0(11))(2)(OH)(4) H(2)O, have been solved. Shattuckite contains silicate chains similar to pyroxene in a complex association with copper atoms, while the closely related planchéite contains silicate chains similar to amphibole.     

Lévy walks evolve through interaction between movement and environmental complexity

Ecological theory predicts that animal movement is shaped by its efficiency of resource acquisition. Focusing solely on efficiency, however, ignores the fact that animal activity can affect resource availability and distribution. Here, we show that feedback between individual behavior and environmental complexity can explain movement strategies in mussels. Specifically, experiments show that mussels use a Lévy walk during the formation of spatially patterned beds, and models reveal that this Lévy movement accelerates pattern formation. The emergent patterning in mussel beds, in turn, improves individual fitness. These results suggest that Lévy walks evolved as a result of the selective advantage conferred by autonomously generated, emergent spatial patterns in mussel beds. Our results emphasize that an interaction between individual selection and habitat complexity shapes animal movement in natural systems.