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.     

Games played by rogue proteins in prion disorders and Alzheimer's disease

The incidence of Alzheimer's disease (AD) and that of prion disorders (PrD) could not be more different. One-third of octogenarians succumb to AD, whereas Creutzfeldt-Jakob disease typically affects one individual in a million each year. However, these diseases have many common features impinging on the metabolism of neuronal membrane proteins: the amyloid precursor protein APP in the case of AD, and the cellular prion protein PrPC in PrD. APP begets the Abeta peptide, whereas PrPC begets the malignant prion protein PrPSc. Both Abeta and PrPSc are associated with disease, but we do not know what triggers their accumulation and neurotoxicity. A great deal has been learned, however, about protein folding, misfolding, and aggregation; an entirely new class of intramembrane proteases has been identified; and unsuspected roles for the immune system have been uncovered. There is reason to expect that prion research will profit from advances in the understanding of AD, and vice versa.     

Infection-specific particle from the unconventional slow virus diseases

Scrapie-associated fibrils, first observed in brains of scrapie-infected mice, were also observed in scrapie-infected hamsters and monkeys, in humans with Creutzfeldt-Jakob disease, and in kuru-infected monkeys. These fibrils were not found in a comprehensive series of control brains from humans and animals affected with central nervous system disorders resulting in histopathologies, ultrastructural features, or disease symptoms similar to those of scrapie, kuru, and Creutzfeldt-Jakob disease. These fibrils are also found in preclinical scrapie and in the spleens of scrapie-infected mice; they are a specific marker for the "unconventional" slow virus diseases, and may be the etiological agent.     

Butler, missouri: an iron meteorite with extremely high germanium content

The Butler iron meteorite has been found to have a germanium concentration of 2000 parts per million, which is about five times higher than the highest concentration that has been measured previously in an iron meteorite. The gallium concentration is 87 parts per million, which is among the highest concentrations found in these objects. The nickel content is 16.0 percent, the second highest nickel concentration known in a meteorite displaying a Widman st?tten pattern. The high Ge/Ni ratio, as well as the association of a high nickel content with high gallium and germanium contents, make this object an exception to two geochemical generalizations regarding the iron meteorites.     

基于生产潜力的2020年山东省粮食贡献情景分析

根据耕地、复种、粮作比例、播面单产("播种面积单产"简称,下同)、人均消费需求等不同条件组合研究,讨论不同情景下山东省各县的粮食产量和人粮关系,向省级层面汇总,对2020年(全面小康)山东省粮食贡献的未来前景进行系统分析,探讨不同情景下山东省人口-土地-粮食的互动关系,为我国人粮关系协调发展提供决策依据。研究结果表明,在不同耕地、复种指数、粮作比例和播面单产组合下,山东省2020年粮食产量在2 789万t和4 892万t之间,不同的生产经营对粮食生产具有较大的影响;如全国均处于耕地高供给能力、高复种指数、高粮作比例、低单产、高消费的背景下,2020年山东省的粮食总产量为4 403万t,占国家粮食总产量的6.79%,在全国31省级单位(港、澳、台除外)中位居第三;与2000年相比,人口可增长量为787万人,在全国31省级单位中居第13位,人口可增长率为8.75%,在全国居第17位;山东省在国家粮食生产中地位较为重要,生产能力位居前列,但由于人口基数大,人口增长空间有限,提供余粮的作用有限。     

Ethyl mercury p-toluene sulfonanilide: lethal and reproductive effects on pheasants

Ethyl mercury p-toluene sulfonanilide (active ingredient of Ceresan M) at a dietary concentration of 30 parts per million (12.5 parts of mercury per million) was lethal to adult ring-necked pheasants. Egg production and survival of third-week embryos were sharply reduced when breeders were maintained on feed containing 10 parts of this compound per million (4.2 parts of mercury per million).     

基于LMDI模型的新疆粮食生产影响因素分析

从新疆耕地利用角度出发,对影响新疆粮食生产变化的因素进行时间和空间上的科学分析,应用对数平均迪氏分解法(Logarithmic mean weigh division,LMDI)对2000~2014年新疆粮食生产影响因素进行分解研究,因素分别分解为耕地面积、粮食单产、复种指数和粮作比例,同时,对粮食产量变动及其分解因素的统计指标在GIS中属性挂链进行空间分析。结果表明,(1)2014年全新疆粮食总产量为1 390.81万t,15年间粮食产量增加552.03万t,其中在14个地州中,塔城地区的粮食增加量最多达到209.70万t;(2)耕地面积、复种指数、粮作比例和粮食单产的贡献产量分别为231.67万t,377.26万t,-202.32万t和145.41万t;(3)从各地州看,粮食生产空间格局分异大,各个分解因素的累加效应存在区域性空间差异。     

Erratum

The article "Back to the energy crisis" by Mark Crawford (News & Comment, 6 Feb., p. 626) overstated American imports of petroleum and petroleum products for the years 1977 and 1985. Imports in 1977 averaged 8.8 million barrels per day as opposed to 8807 million barrels as stated. By 1985 imports had fallen to 5.07 (rounded) million barrels per day, not 5067 million barrels daily. The United States' use of petroleum-not foreign consumption as stated in the article-is projected to hit 17.7 million barrels per day in 1995. U.S. imports could then reach 9.8 million barrels a day.     

DDE residues and eggshell changes in Alaskan falcons and hawks

Eggshell thickness after exposure to DDT was reduced by 21.7 percent in Alaskan tundra peregrines, by 16.8 percent in taiga peregrines, by 7.5 percent in Aleutian peregrines, by 3.3 percent in rough-legged hawks, and not at all in gyrfalcons. Tundra peregrine eggs contain an average of 889 parts of DDE per million (lipid basis); taiga peregrine eggs contain 673 parts per million; Aleutian peregrine eggs contain 167 parts per million; rough-legged hawk eggs contain 22.5 parts per million; and gyrfalcon eggs contain 3.88 parts per million. These changes in eggshell thickness and the pesticide residues reflect different degrees of exposure to contamination. There is a highly significant negative correlation between shell thickness and DDE content in peregrine eggs. Tundra and taiga peregrines have fledged progressively fewer young each year since 1966.     

基于ArcGIS的烟台市森林生态系统积累营养物质功能评价

林木营养积累是地球生物化学循环中非常重要的部分,对维持生物与非生物环境间物质交换平衡有重要作用。基于实测,对烟台市森林生态系统积累营养物质功能进行评估,依托ArcGIS进行数据空间分析,以分析营养物质积累在树种间、县区间、地形间的数值和空间差异,结果表明,烟台市森林生态系统积累元素总实物量为11 190.5 t·a^-1,积累N、P、K的物质量分别为6 787.29、776.04、3 627.16 t·a^-1;积累元素的总价值量为16 794.83万元·a^-1,积累N、P、K的价值量分别为14 253.36、543.23、1 998.24万元·a^-1。单位面积积累元素实物量为21.48 kg·hm^-2·a^-1,单位面积价值量为322.2元·hm^-2·a^-1。单位面积森林资源积累营养元素的能力在树种间、县区间、不同地形间存在着不同程度的差异。     

广藿香棒孢霉叶斑病拮抗菌的分离鉴定及生物农药的筛选

广藿香棒孢霉叶斑病是广藿香生产上的重要病害,从种植广藿香的土壤中分离到1株能明显抑制其病原菌多主棒孢的拮抗细菌,通过序列分析将其鉴定为铜绿假单胞菌。该菌株能够显著抑制多主棒孢菌丝生长,抑菌带宽达10 mm。另外,选用6种生物药剂对广藿香棒孢霉叶斑病病原菌进行室内筛选。结果表明,300亿/g蜡质芽孢杆菌WP、2亿/mL碧拓、4%嘧啶核苷类抗菌素WG、1.1%儿茶素WP和10%多抗霉素WP等5种药剂在说明书配制浓度的范围之内都达到了很好的抑制效果,3%中生菌素WP没有抑菌效果。     

密度对大穗型小麦新品系1624干物质转移特性的影响

在大田试验条件下,研究密度对大穗型小麦新品系1624、多穗型品种小偃22灌浆期干物质转运特性的影响。采用随机区组设计,设置4个密度处理,基本苗分别为90万/hm2(T1)、150万/hm2(T2)、210万/hm2(T3)、270万/hm2(T4)。结果表明,在开花期与成熟期各品种(系)地上部单株干质量均随密度增大而减轻;成熟期籽粒干质量1624以150万/hm2的密度最大、小偃22以90万/hm2的密度最大;各品种(系)营养器官干物质转移量均以基本苗为210万/hm2最多、90万/hm2最少,大穗型品系1624转移量多于多穗型品种小偃22;营养器官对籽粒发育的贡献率1624为随密度增大而增大,小偃22为随密度增大先增大后减小;各品种(系)灌浆持续时间均随密度增大而延长,各品种不同密度间平均灌浆速率与理论千粒质量大小顺序均为T1>T3>T2>T4;大穗型品系1624基本苗在210万/hm2左右时产量因子较为协调,多穗型品种小偃22基本苗在150万/hm2时产量因子较为协调。     

Solar particle tracks in glass from the surveyor 3 spacecraft

A glass filter from Surveyor 3 has a surface density of approximately 1 x 10(6) tracks per square centimeter from heavy solar flare particles. The variation with depth is best fitted with a solar particle spectrum dN/dE = 2.42 x 10(6) E(-2) [in particles per square centimeter per year per steradian per (million electron volts per nucleon)], where E is the energy and N is the number of particles, from 2 million electron volts per nucleon to approximately 7 million electron volts per nucleon and dN/dE = 1.17 x 10(7) E(-3) at higher energies. Not much difference is observed between 0.5 and 5 micrometers, an indication that there is a lack of track-registering particles below 0.5 million electron volts per nucleon. The Surveyor data are compatible with track results in lunar rocks, provided an erosion rate of approximately 10(-7) centimeter per year is assumed for the latter. The results also suggest a small-scale erosion process in lunar rocks.     

密度和肥力对长穗小麦86(306)产量及构成因素的影响

为了研究长穗小麦新品系86(306)对密度和肥力变化的反应,试验设置了4种密度和4种肥力水平。结果表明,在密度为345万/hm2下,施肥N:315 kg/hm2,P2O5:240 kg/hm2的处理可以使长穗小麦86(306)的产量达到最大值;产量构成因素穗数、穗粒数和千粒重分别在密度345万/hm2,施肥N:315 kg/hm2,P2O5:240 kg/hm2;密度120万/hm2,施肥N:415 kg/hm2,P2O5:240 kg/hm2和密度345万/hm2,施肥下N:315 kg/hm2,P2O5:240 kg/hm2达到极大值。     

玉米全程机械化高产耕作栽培技术模式及产量效益分析

通过对玉米品种的筛选、机械化技术、耕作栽培技术、高效定量深施肥技术、病虫草害综合防治技术等进行综合组装配套集成,在哈尔滨市第一积温带的3个地区、6个试验点,形成玉米全程机械化高产耕作栽培技术模式,2008年和2009年核心示范面积累计达31 hm2,辐射带动6 667 hm2.a-1玉米生产,共节本增效为3 893.1万元.a-1。     

Oxidant effects on californian coastal sage scrub

Causes for the reduced cover of native species of coastal sage scrub in certain southern Californian sites wvere sought among 43 habitat variables. The mean annual concentration of oxidants (which averaged 18 parts per 100 million on the 11 most polluted sites) is statistically indicated as the most likely causal factor. Sites of high oxidant levels in the region are also characterized by declining species richness and equitability.     

优良玉米杂交种农大3138的选育与推广

农大3138的选育主要是针对生产用品种的缺点和弱点,通过亲本材料的科学选择,实现性状互补,加大亲本间的遗传差距;同时加大适应性、抗逆性和抗病性等的选择压。该品种在多年各类区域试验中表现优异,名列1,2位。先后通过北京市、山西省、河北省及国家品种审定。山西省近3年种植面积累计达40.7万hm2,居省内玉米品种占有面积的第1位(2年)和第2位(1年),总增产1.5亿kg。1997～2001年在国内9省市累计推广166.7万hm2,其中2001年种植面积达53.3万hm2。全国5年累计增产玉米12.5亿kg,增收12.5亿元。制种增收获利1.25亿元。     

稀植栽培下春小麦旗叶光合性状的变化规律

试验选用适宜稀植栽培的三个春小麦品种,设三个处理A1:600万株.hm-2(三叶期开沟施肥),A2:450万株.hm-2(三叶期开沟施肥,花期叶面喷肥),A3:300万株.hm-2(花期叶面喷肥)。结果表明,三个品种旗叶叶绿素总量Chl(a+b)和叶绿素a/b值变化规律不同,东农122、龙麦26的Chl(a+b)最大值出现在300万株密度下,克丰6出现在450万株密度下。稀植栽培下比叶重也有不同程度提高,东农122、龙麦26在A1、A2处理下明显高于A3处理。     

杭州西湖湖西景区土地利用/覆被变化与生态服务价值评估

采用3S技术对杭州西湖湖西综合保护工程实施前后进行对比研究,分析了工程实施前后土地利用/覆被状况和生态系统服务价值的变化。结果表明:2001-2008年,湖西景区未利用地、建设用地和耕地面积减少,草地、林地和水域面积增加。湖西景区年总生态价值从2001年的421.15万元增加到2008年的1 095.59万元,增加了160.14%。表明湖西综合保护工程优化了生态环境和社会环境,是实现区域可持续发展的工程。     

Sulfur isotopic composition of cenozoic seawater sulfate

A continuous seawater sulfate sulfur isotope curve for the Cenozoic with a resolution of approximately 1 million years was generated using marine barite. The sulfur isotopic composition decreased from 19 to 17 per mil between 65 and 55 million years ago, increased abruptly from 17 to 22 per mil between 55 and 45 million years ago, remained nearly constant from 35 to approximately 2 million years ago, and has decreased by 0.8 per mil during the past 2 million years. A comparison between seawater sulfate and marine carbonate carbon isotope records reveals no clear systematic coupling between the sulfur and carbon cycles over one to several millions of years, indicating that changes in the burial rate of pyrite sulfur and organic carbon did not singularly control the atmospheric oxygen content over short time intervals in the Cenozoic. This finding has implications for the modeling of controls on atmospheric oxygen concentration.