973 resultados para 6-54


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A importância deste tratado para o Brasil é atribuir a Colônia de Sacramento a Portugal, origem de guerras e disputas posteriores. Em consequência interessa também ao Uruguai e à Argentina.

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Since 2002 Germany is obliged to collect fishery data to support the European Common Fishery Policy. Sampling of the com-mercial fishery under German flag is one duty within the EU fisheries data collection programme. During the past 6 years, 148 fishing trips were sampled by scientific observers onboard commercial fishing vessels to collect data on catch composi-tions with special emphasis on the proportions of landed and discarded fish. The results show that the proportion of discard is depending on the fishery. Highest discard rates were observed on beam trawl fishing trips. At the level of individual fishing trips, discard rates varied extremely within a fishery segment. Highest variations were found in the beam and bottom otter trawl fishery. In contrast, the discard rates in high-seas fisheries were low.

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This publication gives the results of the bottom trawlings made during the cruises Togo 5 and Togo 6 by the oceanographic research vessel "Andre Nizery" on the continental shelf of Togo during the estimation program of halieutic resources. The report includes: 1 - the report of the cruises Togo 5 and Togo 6; 2 - Some information on the presentation of the results; 3 - the trawl recording maps for the 2 cruises; 4 - The length frequency distributions of the measured samples.

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对两种不同基因型小麦京411(北京地区高产小麦品种)和小偃54(在生产上已应用二十年的优良品种)幼苗及旗叶光抑制特性进行了比较研究,着重探讨了它们抗光氧化的差异及其机理,主要结果如下: 1. 强光条件下,同京411相比小偃54能保持较高的光合色素含量和放氧速率。其DCPIP光还原活性也较高。 2. 光谱特性分析表明,强光胁迫下小偃54在红区及蓝区的特征性吸收峰及F683荧光发射峰下降的幅度明显小于京411相应峰位的下降。 3. 色素蛋白复合物分析表明,强光条件下,京411色素蛋白复合物中LHCII聚合体大量的解聚,而小偃54在强光条件下仍能保持较高比例的LHCII聚合体。这可能在一定的程度上有利于小偃54在强光下维持较强的激发能耗散的能力。 4. 多肽SDS-PAGE分析表明,强光对不同基因型小麦中同PSII光抑制敏感性有关的两个外周蛋白23kD和17kD的影响不同。光抑制明显地降低了京411的23kD和17kD的含量,而对于小偃54中这两个外周蛋白23kD和17kD的影响不大。强光条件下小偃54旗叶PSII颗粒中捕光色素蛋白27kD含量提高,而京411捕光色素蛋白27kD含量明显的下降。 5. 上述结果表明,西北地区的优良小麦品种小偃54同北京地区的高产品种京411相比更耐强光的胁迫,其抗光氧化的能力较强。 6. 进一步分析表明,同京411相比,小偃54抗光氧化的主要原因是其不仅含有较大的叶黄素循环的色素库,而且在强光下能维持高的VDE酶活性及高水平的叶黄素循环的脱环化水平。 7. 叶黄素循环色素在两个小麦品种类囊体膜色素蛋白复合体中的分布存在差异,抗光氧化的小偃54大部分的VAZ分布在PSII上,其中绝大部分集中在LHCII聚合体上。LHCII上VAZ的集中分布可能有利于在强光下对过多光能的耗散,减少过多激发能对PSII的损伤。 8. 类囊体膜流动性分析表明,叶黄素循环参与了对类囊体膜流动性的调整,对维持强光下抗光氧化品种小偃54的类囊体膜相对稳定起重要作用。 9. 依赖于叶黄素循环的热耗散是抗光氧化品种小偃54的一个主要的光保护途径。

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α-(Yb1-xErx)2Si2O7 thin films on Si substrates were synthesized by magnetron co-sputtering. The optical emission from Er3+ ions has been extensively investigated, evidencing the very efficient role of Yb-Er coupling. The energy-transfer coefficient was evaluated for an extended range of Er content (between 0.2 and 16.5 at.%) reaching a maximum value of 2 × 10⁻¹⁶ cm⁻³s⁻¹. The highest photoluminescence emission at 1535 nm is obtained as a result of the best compromise between the number of Yb donors (16.4 at.%) and Er acceptors (1.6 at.%), for which a high population of the first excited state is reached. These results are very promising for the realization of 1.54 μm optical amplifiers on a Si platform.

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The cross-section ratios of double-, triple-, quadruple-, and the total multi-electron processes to the single electron capture process sigma(DE)/sigma(SC), sigma(TE)/sigma(SC), sigma(QE)/sigma(SC) and sigma(ME)/sigma(SC)) as well as the relative ratios among reaction channels in double-electron active, triple-electron active and quadruple- electron active are measured in C-13(6+) -Ne collision in the energy region of 4.15-11.08 keV/u by employing position-sensitive and time-of-flight coincident techniques. It is determined that the cross-section ratios sigma(DE)/sigma(SC), sigma(TE)/sigma(SC), sigma(QE)/sigma(SC) and sigma(ME)/sigma(SC) are approximately the constants of 0.20 +/- 0.03, 0.16 +/- 0.04, 0.06 +/- 0.02 and 0.42 +/- 0.05. These values are obviously smaller than the predictions of the molecular Coulomb over-the-barrier model (MCBM) [J. Phys. B 23 (1990) 4293], the extended classical over-the-barrier model (ECBM) [J. Phys. B 19 (1986) 2925] and the semiempirical scaling laws (SL) [Phys. Rev. A 54 (1996) 4127]. However, the relative ratios among partial processes of DE, TE and QE are found to depend on collision energy, which suggests that the collision dynamics depends on the collision velocity. The limitation of velocity-independent character of ECBM, MCBM and SL is undoubtedly shown.

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The title compound, C24H24O3Si2, is a twofold symmetric silicocrown ether with the two dimethylsilyl groups attached to the O atoms of 1,1'-bi-2-naphthol, and bridged by another O atom.

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Marine bacterium Vibrio sp. F-6, utilizing agarose as a carbon source to produce agarases, was isolated from seawater samples taken from Qingdao, China. Two agarases (AG-a and AG-b) were purified to a homogeneity from the cultural supernatant of Vibrio sp. F-6 through ammonium sulfate precipitation, Q-Sepharose FF chromatography, and Sephacryl S-100 gel filtration. Molecular weights of agarases were estimated to be 54.0 kDa (AG-a) and 34.5 kDa (AG-b) by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The optimum pH values for AG-a and AG-b were about 7.0 and 9.0, respectively. AG-a was stable in the pH range of 4.0-9.0 and AG-b was stable in the pH range of 4.0-10.0. The optimum temperatures of AG-a and AG-b were 40 and 55 degrees C, respectively. AG-a was stable at temperature below 50 degrees C. AG-b was stable at temperature below 60 degrees C. Zn2+, Mg2+ or Ca2+ increased AG-a activity, while Mn2+, Cu2+ or Ca2+ increased AG-b activity. However, Ag+, Hg2+, Fe3+, EDTA and SDS inhibited AG-a and AG-b activities. The main hydrolysates of agarose by AG-a were neoagarotetraose and neoagarohexaose. The main hydrolysates of agarose by AG-b were neoagarooctaose and neoagarohexaose. When the mixture of AG-a and AG-b were used, agarose was mainly degraded into neoagarobiose.

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报道了点地梅属6种12个居群的染色体数目和核型。它们的染色体数目(2n)、核型公式(KF)、染色体相对长度组成(CRL)、核型不对称性系数(A. sK%)和核型类型(KT)分别为:点地梅在南京的2个居群都是2n=2x=20,KF=18m+2sm, CRL=2L+6M_2+10M_1+2S,核型KT属于1A型,但核型不对称性系数As. K%分别是55.04%和56.71%;北点地梅在内蒙古锡林郭勒和白音锡勒居群的2n=2x=20,KF分别为16m+2sm+2st+1b和16m+2sm+2st+4b,染色体相对长度组成分别是14M_2+4M_1+2S+1b和12M_2+6M_1+2S+4b,核型不对称性系数As. K%分别是57.65%和58.86%,属2A型和2B型;高原点地梅在青海玛沁县昌马河居群和兴海县温泉居群都是2n=2x=20,KF=10m+8sm+2st。但相对长度组成分别为12M_2+8M_1和4L+6M_2+6M_1+4S, As. K%分别是60.35%和62.57%,属2A型和2B型;雅江点地梅在青海玛多县巴颜喀拉山居群和大通县达坡山居群分别为2n=4x=40和20n=6x=60,KF=36m+2sm+2st和KF=46m+10sm+4st+2b, CRL=2l+20M_2+14M_1+4S和GRL=6L+30M_2+16M_1+8S+2b, As.K%分别为55.62%和58.31%,核型均属于2B;巴颜喀拉山北坡的鳞叶点地梅2n=40、60、80。西藏点地梅青湖居群中有2种细胞型:①2n=2x=24, KF=12m+6sm+6st+4b, CRL=6L+2M_2+8M_1+4S+4b, As. K%=65.74%,核型属2B;②2n=2x=22,KF=14m+4sm(2SAT)+4st, CRL=4L+6M_2+8M_1(2SAT)+4S,As. K%=63.40%,核型也属于2B。西宁西山湾居群也有2种细胞型;①2n=3x=36, KF=36m,CRL=4L+12M_2+20M_1, As. K%=54.82%,核型属1A;②2n=3x=33,KF=33m, CRL=3L+12M_2+18M_1,As. K%=52.11%,核型属1A。点地梅属的染色体原始基数可能是x=10,在种间或种内观察到有3种核型变化:染色体非整倍性变化、多倍化和核型不对称性变化。将2倍体居群的核型和不对称性进行比较,可以看出点地梅是较对称的核型。因此,在研究的种中应是比较原始的类群。北点地梅的核型不对称性和进化程度高于点地梅而低于高原点地梅和西藏点地梅。染色体多倍化的雅江点地梅、鳞叶点地梅和西藏点地梅等在核型上也许是最进化的类群。

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We report on measurements of the saturated single frequency output of a Ge XXIII x-ray laser on the J=0-->1 transition at 19.6 nm from a refraction compensating double target driven by 150 J of energy from 75-ps Nd-glass laser pulses. The 19.6-nm line completely dominated the laser output. The output energy was measured to be 0.9 mJ in a beam of 6.6x30 mrad(2) divergence, corresponding to a conversion efficiency of 6 x 10(-6).