全球桉树人工林发展面临的困境与对策

桉树人工林是世界人工林的重要组成部分,在木材供给和应对气候变化等方面扮演着越来越重要的角色。世界热带亚热带地区的国家都在大力发展桉树人工林,使全球桉树人工林的面积呈现不断增加的趋势,近15年来全球桉树人工林面积年平均增长110万hm~2。面对可利用林地资源的限制、立地条件的制约、气候变化的胁迫、社会对林产品需求的变化,以及社会舆论博弈的影响,世界桉树人工林必将在营林制度、经营策略和经营途径方面发生深刻变化和重大调整。营林制度上由短周期纯林连作的林分经营转变为短中长周期循环混交轮作的景观经营,经营策略上从注重桉树造林面积扩张转变为人工林单产和生态系统服务的全面提升,经营途径上更加重视多目标森林生态系统可持续经营将成为未来桉树人工林发展的主流趋势。然而,在由单一的木材经营转变为多目标森林生态系统可持续经营过程中,桉树人工林仍将保持以木材生产为主导功能的发展格局,这是桉树人工林的比较优势和特点决定的。但有效权衡和协同桉树木材生产主导功能与其他生态服务功能是今后经营的方向。     

Disrupted function and axonal distribution of mutant tyrosyl-tRNA synthetase in dominant intermediate Charcot-Marie-Tooth neuropathy

Charcot-Marie-Tooth (CMT) neuropathies are common disorders of the peripheral nervous system caused by demyelination or axonal degeneration, or a combination of both features. We previously assigned the locus for autosomal dominant intermediate CMT neuropathy type C (DI-CMTC) to chromosome 1p34-p35. Here we identify two heterozygous missense mutations (G41R and E196K) and one de novo deletion (153-156delVKQV) in tyrosyl-tRNA synthetase (YARS) in three unrelated families affected with DI-CMTC. Biochemical experiments and genetic complementation in yeast show partial loss of aminoacylation activity of the mutant proteins, and mutations in YARS, or in its yeast ortholog TYS1, reduce yeast growth. YARS localizes to axonal termini in differentiating primary motor neuron and neuroblastoma cultures. This specific distribution is significantly reduced in cells expressing mutant YARS proteins. YARS is the second aminoacyl-tRNA synthetase found to be involved in CMT, thereby linking protein-synthesizing complexes with neurodegeneration.     

较大水溶性单体乳液聚合动力学研究

以较大水溶性单体甲基丙烯酸甲酯乳液聚合体系为研究对象,利用膨胀计研究了在一定温度一定搅拌速度下乳化剂及引发剂浓度对聚合反应速率、乳胶粒直径及数目以及聚合物分子量的影响,并将试验数据与低水溶性单体乳液聚合数学模型预计的结果进行了拟合,得到了对于乳液聚合过程数学模型化很有价值的结论。     

云南省东北部两栖爬行动物调查

本文报告了云南东北部两栖爬行动物组成,垂直分布,与邻近地区的相似性.提出我国两栖动物地理区划中的华中区与西南区在该地的界线应以乌蒙山分水岭为界.     

福建柰树昆虫种类调查

本文对福建省古田县、浦城县、永泰县、光泽县和福州市等地的柰树昆虫种类进行了调查,初步鉴定出88种;对重要种类的生活习性进行初步分析。     

Identification of the familial cylindromatosis tumour-suppressor gene

Familial cylindromatosis is an autosomal dominant genetic predisposition to multiple tumours of the skin appendages. The susceptibility gene (CYLD) has previously been localized to chromosome 16q and has the genetic attributes of a tumour-suppressor gene (recessive oncogene). Here we have identified CYLD by detecting germline mutations in 21 cylindromatosis families and somatic mutations in 1 sporadic and 5 familial cylindromas. All mutations predict truncation or absence of the encoded protein. CYLD encodes three cytoskeletal-associated-protein-glycine-conserved (CAP-GLY) domains, which are found in proteins that coordinate the attachment of organelles to microtubules. CYLD also has sequence homology to the catalytic domain of ubiquitin carboxy-terminal hydrolases (UCH).     

Substantial reservoirs of molecular hydrogen in the debris disks around young stars

Circumstellar accretion disks transfer matter from molecular clouds to young stars and to the sites of planet formation. The disks observed around pre-main-sequence stars have properties consistent with those expected for the pre-solar nebula from which our own Solar System formed 4.5 Gyr ago. But the 'debris' disks that encircle more than 15% of nearby main-sequence stars appear to have very small amounts of gas, based on observations of the tracer molecule carbon monoxide: these observations have yielded gas/dust ratios much less than 0.1, whereas the interstellar value is about 100 (ref. 9). Here we report observations of the lowest rotational transitions of molecular hydrogen (H2) that reveal large quantities of gas in the debris disks around the stars beta Pictoris, 49 Ceti and HD135344. The gas masses calculated from the data are several hundreds to a thousand times greater than those estimated from the CO observations, and yield gas/dust ratios of the same order as the interstellar value.     

人民是创造西藏社会历史发展的决定力量：纪念西藏和平解放五十周年

1951年5月23日,中央人民政府与原西藏地方政府签订了《关于和平解放西藏办法的协议》（即七十条协议）。从此,西藏在中国共产党的领导下实现了和平解放,回到了祖国大家庭中,并永远摆脱了帝国主义的侵略和羁绊,结束了西藏近代社会的黑暗历史,特别是1959年,通过平息叛乱和民主改革的斗争,使西藏的政治、经济、化等各项社会事业实现了由封建农奴制社会向社会主义社会的历史性跨越。党的十一届三中全会以来,西藏各民族人民在坚持高举邓小平同志关于建设有中国特色社会主义理论的伟大旗帜的同时,以中央三次西藏工作会议为契机,紧密团结在以江泽民同志为核心的党中央周围,在党中央的亲切关怀和全国人民的大力无私援助下,结合西藏的实际,以团结奋斗的精神和开拓进取思想,取得了伟大的社会主义建设和改革开放的辉煌成就。