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1.
Emission features from ionized carbon dioxide and carbon monoxide were measured in the 1900- to 4300-angstrom spectral region. The Lyman alpha 1216-angstrom line of atomic hydrogen and the 1304-, 1356-, and 2972-angstrom lines of atomic oxygen were observed.  相似文献   

2.
Wide-angle photography of Barnard's Loop Nebula suggests that the nebular emission is much less intense in the 1230- to 2100-angstrom spectral region than in the 2200- to 3200-angstrom near-ultraviolet region. This contrast may be due to differences in the absorption or scattering properties of the interstellar grains in these two wavelength regions.  相似文献   

3.
In a conventional class I ribonucleotide reductase (RNR), a diiron(II/II) cofactor in the R2 subunit reacts with oxygen to produce a diiron(III/IV) intermediate, which generates a stable tyrosyl radical (Y*). The Y* reversibly oxidizes a cysteine residue in the R1 subunit to a cysteinyl radical (C*), which abstracts the 3'-hydrogen of the substrate to initiate its reduction. The RNR from Chlamydia trachomatis lacks the Y*, and it had been proposed that the diiron(III/IV) complex in R2 directly generates the C* in R1. By enzyme activity measurements and spectroscopic methods, we show that this RNR actually uses a previously unknown stable manganese(IV)/iron(III) cofactor for radical initiation.  相似文献   

4.
以墨白962的不同世代为材料,研究了混合选择对热带玉米群体穗分化的选择响应。结果表明,在混合选择过程中,雄穗的穗分化阶段I、IV和V所用时间在的C0、C2和C4等3个世代之间无显著性差异;但是雄穗的分化阶段II和III所用时间在世代C0和C4之间有显著差异。而穗子的穗分化阶段I和II在C4、C0和C2世代之间有显著差异。对于雄穗和穗子相同穗分化阶段的时间差,在不同世代之间无显著差异。  相似文献   

5.
王卫东 《安徽农业科学》2012,40(34):16682-16684
介绍了博山精细化农业气候区的划分,根据以热量指标为主以干燥度指标为辅的原则将博山区划分为4个农业气候区,其中第4农业气候区又划分为2个亚区,并对各个气候分区的范围、气候资源状况、适宜种植作物及发展方向、面临的气象灾害和应对措施进行了分析。结果表明,Ⅰ区以灌溉农业为主,粮食作物应以冬小麦和夏玉米为主,是博山一年两熟制最有保证的地区,靠近城区的乡镇大力发展蔬菜生产;Ⅱ区是博山仅次于Ⅰ区的主要农业生产基地,境内热量条件可以满足桃、猕猴桃、苹果等果树的生长,以及旱田西红柿、大白菜的生产和黄烟的种植,近年来在政府部门的规划下,重点形成了石马鲜桃,郭庄长茄、北博山黄烟、大白菜、以源泉为主的猕猴桃生产基地;Ⅲ区以旱作物农业为主,热量条件能够满足两年三熟制的要求,粮食作物组合应以春谷子+小麦+早熟玉米为主,重点发展"黑五类"、金银花、桔梗等中药材以及日照绿茶;Ⅳ1区气候寒凉,只能满足一年一熟的热量要求,因干旱严重,粮食作物应首选谷子作为当家品种,冷凉的气候是种植马玲薯的优势气候条件;Ⅳ2区热量少,坡度大,仅适宜发展林业,树种以油松与紫穗槐或落叶松与椴树混交为好。对于各个不同气候区面临的干旱、干热风、霜冻、冰雹、暴雨等不同的气象灾害,重点是改善生态环境,兴修农田水利设施。在合理利用气候资源的情况下统筹规划,集约化发展,加快土地流转,大力发展现代设施农业才是农业发展和提高农民收入的根本。  相似文献   

6.
本文对华钩藤95%乙醇提取物的氯仿部分的非生物碱类成分进行分离纯化,通过理化性质和波谱技术(MS、1H-NMR、13C-NMR)鉴定所得化合物的结构。分离得到8个非生物碱类成分,分别为乌苏酸(I)、β-谷甾醇(II)、奎洛维酸(III)、胡萝卜苷(IV)、奎洛维酸-3-O-β-D-海藻糖苷(V)、3β,5α,6β-三羟基豆甾烷(Ⅵ)、齐墩果酸(VII),奎洛维酸-3-O-β-D-吡喃葡萄糖苷(28→1)-β-D-吡喃葡萄糖苷(VIII),其中化合物III、V、Ⅵ、VIII为首次从钩藤属植物中分离得到。  相似文献   

7.
复方中草药对断奶仔猪生产性能和肠道结构的影响   总被引:2,自引:0,他引:2  
研究了复方中草药添加剂对断奶仔猪生产性能和肠道形态结构的影响,结果表明:试验ⅡⅢ和Ⅳ组均能一定程度提高断奶仔猪的日平均采食量,促进仔猪的生长速度,且试验Ⅳ组效果最好;试验Ⅱ,Ⅲ和Ⅳ组的各肠段绒毛长与隐窝深度与对照组差异均极显著(P<0.01),且试验Ⅳ组的十二指肠、回肠和试验Ⅲ组的空肠绒毛高度显著高于试验Ⅱ(P<0.05);对于绒毛高度与隐窝深度的比值而言,试验Ⅱ,Ⅲ和Ⅳ组均比对照组增大,其中试验Ⅱ组的空肠和试验Ⅲ组的十二指肠、回肠差异达到显著水平(P<0.05)。  相似文献   

8.
Small-angle neutron diffraction (wavelength 4.05 angstroms) of human and rabbit sciatic nerve has been carried out by means of the Brookhaven high flux beam reactor with an automated slit camera. Most of the free water of the nerves was substituted in order to minimize incoherent scatter of hydrogen atoms. The differences in amplitude and phase shifts between neutrons and x-rays resulted in a neutron diffraction pattern that was completely different from the x-ray pattern. The neutron pattern consisted of a single peak of about 89-angstrom spacing in the region examined (up to 6-angstrom spacing). The strong third, fourth, and fifth order reflections (about 60, 45, and 36 angstroms) seen in the x-ray pattern were suppressed. The neutron data indicated a strong scattering from one portion of the membrane.  相似文献   

9.
丁淑荃 《安徽农业科学》2007,35(17):5173-5174
以价廉的菜籽饼作为主要蛋白质饲料原料之一,配制了Ⅰ、Ⅱ、Ⅲ、Ⅳ号4种饵料,用其分别饲喂4组金鲫,进行饲养试验。结果表明:用Ⅱ号饵料饲喂的金鲫相对增长率达到15.31%,饵料系数为1.93,显著优于其他各组。Ⅱ号饵料为最优配方。  相似文献   

10.
选用2胎龄斯格母猪20头,随机分成5个处理,每处理4次重复,仔猪出生3 d内吃乳前饲喂1 mL液态微生态制剂,诱食后在基础日粮中分别添加0.1% 微胶囊(Ⅰ)、0.05% 低聚木糖(Ⅱ)、0.1% 微胶囊和0.05% 低聚木糖(Ⅲ)、0.1% 菌粉和0.05% 低聚木糖(Ⅳ)及对照组(Ⅴ),观察其对仔猪生长性能、黄白痢发生率和死亡率的影响.结果表明:7日龄内饲喂菌液对体质量增加无明显影响(P>0.05),黄白痢发生率与对照组差异不显著,但仔猪死亡率明显低于对照组(P<0.01).8~28日龄Ⅲ组与Ⅰ、Ⅱ、Ⅴ组仔猪体质量增加差异显著(P<0.05),所有试验组与对照组黄白痢发生率差异极显著(P<0.01),Ⅲ、Ⅳ组与Ⅰ、Ⅱ组黄白痢发生率差异极显著(P<0.01);29~40日龄Ⅲ组与Ⅰ、Ⅱ、Ⅳ、Ⅴ组仔猪体质量增加差异显著(P<0.05),Ⅲ组仔猪黄白痢发生率与其他试验组和对照组差异极显著(P<0.01);试验Ⅰ、Ⅱ、Ⅳ组与Ⅴ组差异显著(P<0.05).  相似文献   

11.
太白七药红毛七化学成分研究   总被引:2,自引:0,他引:2  
[目的]研究太白七药红毛七的化学成分,为其药效成分及作用机理的深入研究奠定基础。[方法]采用硅胶柱色谱、SephadexLH-20、重结晶等方法进行分离纯化,依据理化性质和波谱数据进行结构鉴定。[结果]从红毛七石油醚及乙酸乙酯萃取相中分离得到9个纯品化合物,分别为棕榈酸(Ⅰ)、α-菠菜甾醇(Ⅱ)、α-菠甾醇-β-D-葡萄糖苷(Ⅲ)、β-豆甾醇(Ⅳ)、16α,23,28-三羟基-齐墩果-12-烯-3-O-α-L-阿拉伯吡喃糖苷(Ⅴ)、16α-羟基-齐墩果-12-烯-28-酸-3-O-α-L-阿拉伯吡喃糖苷(Ⅵ)、常春藤皂苷元-3-O-α-L-阿拉伯吡喃糖苷(Ⅶ)、葳严仙皂苷元-3-O-α-L-阿拉伯吡喃糖苷(Ⅷ)、常春藤皂苷元-3-O-β-D-葡萄吡喃糖-(1→2)-α-L-阿拉伯吡喃糖苷(Ⅸ);化合物Ⅰ、Ⅱ、Ⅲ、Ⅴ均为首次从该属植物中分离得到。[结论]该方法可用于研究太白七药红毛七的化学成分,为太白山产红毛七的进一步开发利用提供依据。  相似文献   

12.
The ultraviolet airglow spectrum of Mars has been measured from an orbiting spacecraft during a 30-day period in November-December 1971. The emission rates of the carbon monoxide Cameron and fourth positive bands, the atomic oxygen 1304-angstrom line and the atomic hydrogen 1216-angstrom line have been measured as a function of altitude. Significant variations in the scale height of the CO Cameron band airglow have been observed during a period of variable solar activity; however, the atomic oxygen and hydrogen airglow lines are present during all the observations. Measurements of the reflectance of the lower atmosphere of Mars show the spectral characteristics of particle scattering and a magnitude that is about 50 percent of that measured during the Mariner 6 and 7 experiments in 1969. The variation of reflectance across the planet may be represented by a model in which the dominant scatterer is dust that absorbs in the ultraviolet and has an optical depth greater than 1. The atmosphere above the polar region is clearer than over the rest of the planet.  相似文献   

13.
云南省杨梅生态区划的研究   总被引:3,自引:1,他引:3  
 根据杨梅对生态条件的要求及杨梅的地理分布,对云南省杨梅生态区划进行了探讨。杨梅树对低温敏感,喜冬季温暖,春、夏季湿润的气候。根据杨梅的耐寒性,极端最低气温、年降雨量及果实成熟时期(5~6月)干燥度的分布,将云南省杨梅区划分为4个区:最适宜区(I)、适宜区(II)、次适宜区(III)和不适宜区(IV)。I和II区适宜于杨梅栽培,在III区应精心选择小气候栽培杨梅,并防御杨梅受冻害。  相似文献   

14.
Type III secretion systems (TTSSs) mediate translocation of virulence factors into host cells. We report the 17-angstrom resolution structures of a central component of Salmonella typhimurium TTSS, the needle complex, and its assembly precursor, the bacterial envelope-anchored base. Both the base and the fully assembled needle complex adopted multiple oligomeric states in vivo, and needle assembly was accompanied by recruitment of the protein PrgJ as a structural component of the base. Moreover, conformational changes during needle assembly created scaffolds for anchoring both PrgJ and the needle substructure and may provide the basis for substrate-specificity switching during type III secretion.  相似文献   

15.
 根据荔枝生长发育与气候条件的关系,确定荔枝栽培的气候区划。选择云南134个气候站点,将其中51个30年平均最低气温高于-4 ℃的气候站点划分为可栽培区,另外83个30年平均最低气温低于-4 ℃的气候站点划分为不宜栽培区。再根据19个气候要素,应用聚类分析将51个可栽培区划分为适宜区(Ⅰ),较适宜区(II),次适宜区(III)和较次适宜区(Ⅳ)等4个等级。其中,适宜区、较适宜区和次适宜区可以作为云南省荔枝生产的主要区域。  相似文献   

16.
The response of female boll weevils to males, Anthonomus grandis Boheman, in laboratory bioassays can be reproduced by exposure to a mixture of compounds I, II, and either III or IV, all isolated from male weevils and their fecal material. The same response was elicited by mixtures of tile synthesized coimpounds. Compound I is (+)-cis-2-isopropenyl-l-methylcyclobtutaneethanol; II, cis-3,3-dimethiyl->(1,beta)cyclohexaneethanol; III, cis-3,3-dimethlyl->(1,alpha)-cyclohexaneacetaldehyde; and IV, trans-3,3-dimethyl->(1,alpha)-cyclohexanecetaldehyde.  相似文献   

17.
The polymorphism of sulfur has been investigated by static and dynamic methods up to 500 degrees C at 35 kilobars and up to 350 degrees C at 100 kilobars. The melting curve of sulfur to 31 kilobars and phase boundaries of the so-called "4.04-angstrom phase" have been determined. Evidence has been obtained for phase fields of nine new high-pressure forms of sulfur.  相似文献   

18.
选用体重相近的90日龄生长发育健康的中国白兔32只,雌雄各半,随机分为对照Ⅰ组、试验Ⅱ组、Ⅲ组、Ⅳ组,每天依次在基础日粮中一次性添加0、10、20、30 g的黄芪粉,试验期30 d.结果显示,各试验组与对照Ⅰ组相比,明显提高了血液中血红蛋白的含量,各组间存在极显著差异(P<0.01);随添加黄芪粉剂量的加大,血清中白蛋白含量相应增加,Ⅲ、Ⅳ组间差异不显著(P>0.05),其余组间存在极显著差异(P<0.01);血清总蛋白、天门冬氨酸氨基转移酶及乳酸脱氢酶含量均呈现先增高后降低的趋势,各组间存在极显著差异(P<0.01);血清葡萄糖含量变化趋势同总蛋白,当日添加量在20、30 g时,血清中葡萄糖的含量趋于稳定;Ⅱ组末重、净增重、平均日增重分别与Ⅰ、Ⅲ、Ⅳ组差异显著(P<0.05),Ⅰ、Ⅲ、Ⅳ组间差异不显著(P>0.05),Ⅱ、Ⅲ、Ⅳ组分别比对照Ⅰ组增重提高25.0%、12.5%、8.3%.基础日粮中添加黄芪粉以每日10 g为好,能显著提高饲料报酬及家兔的平均日增重.  相似文献   

19.
The recently reported Pronounced decrease in shear strength of serpentine-bearing rocks at 30 to 40 kilobars in the temperature range 300 degrees to 520 degrees C may be attributed to the transformation of serpentine to a Pressure-dependent, 10-angstrom,2: 1 layer silicate plus brucite and periclase. This reaction increases density by about 8.5 percent.  相似文献   

20.
【目的】开发适用于葡萄香气表型鉴定的分子标记,为葡萄分子辅助育种提供理论依据。【方法】采用固相微萃取结合气相质谱法对45个葡萄品种进行香气组分和含量测定,并分别采用Sanger测序和扩增子测序的方法对葡萄醇酰基转移酶编码基因(VvAAT)结构变异和SNP变异进行分析。【结果】45个葡萄品种中共发现65种香气组分,可以分成酯类、醇类、萜类和醛类4种类型,其中酯类香气含量表现出显著的品种差异性,‘巨峰’等20个葡萄品种酯类香气含量丰富,而‘87-1’等25个葡萄品种检测不到酯类香气;VvAAT共发现了5种结构变异类型,类型I、II、IV和V由于过早终止密码子或片段插入变异,不能正确翻译,仅类型III可以正常翻译,根据其氨基酸序列系统进化树分析结果,又可以分成III.1和III.2两种类型,结合香气测定数据,III.1为功能型,其余均为非功能型;扩增子测序及生信分析发现了8个位于外显子区域的SNP位点(T32C、A69T、G436C、A1247G、A1818T、G1929T、A1959G和C1975G),均导致了编码氨基酸的突变,可以准确区分酯香型品种和非酯香型品种,准确率为97.8%。【结论】葡萄VvAAT位点存在丰富的遗传变异,包括基因结构变异和SNP变异;位于编码区的8个SNP位点能够准确判定葡萄酯类香气表型,可以应用于葡萄分子辅助育种。  相似文献   

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