Wind as a long-distance dispersal vehicle in the Southern Hemisphere

Anisotropic (direction-dependent) long-distance dispersal (LDD) by wind has been invoked to explain the strong floristic affinities shared among landmasses in the Southern Hemisphere. Its contribution has not yet been systematically tested because of the previous lack of global data on winds. We used global winds coverage from the National Aeronautics and Space Administration SeaWinds scatterometer to test whether floristic similarities of Southern Hemisphere moss, liverwort, lichen, and pteridophyte floras conform better with (i) the anisotropic LDD hypothesis, which predicts that connection by "wind highways" increases floristic similarities, or (ii) a direction-independent LDD hypothesis, which predicts that floristic similarities among sites increase with geographic proximity. We found a stronger correlation of floristic similarities with wind connectivity than with geographic proximities, which supports the idea that wind is a dispersal vehicle for many organisms in the Southern Hemisphere.     

基因芯片技术及其在农业上的应用

基因芯片技术是近年来在生命科学技术领域中迅速发展起来的一项高新技术 .本文综述了基因芯片的产生背景、概念、原理、分类和制作方法 ,并展望了其在农业上的应用前景     

“碱法制浆黑液资源化治理”项目的生产性中间试验

利用内蒙古固阳县三鹿纸业有限公司的现有生产流程 ,以实验室研究的蒸煮工艺条件为基础 ,通过 3个周期的大量工业化试验 ,证实了“碱法制浆黑液资源化治理”项目实验阶段确定的工艺技术路线在工业过程中是可行的 ,取得的数据是可靠的 ,同时生产出的纸张具有良好的物理性能、纸浆得率高、硬度低、白度高且几乎无筛渣 ,取得了比实验阶段更好的结果 .废液综合利用减轻了造纸厂对环境的污染 ,回收了碱木素和磺酸盐木素 ,为中小型造纸厂今好的发展提供了很好的技术支持 ,也为该项目实现工业化打下了基础 .     

中国农业补贴政策及其实施效果分析

近几年,中央根据粮食产销形势的新变化,先后出台了良种补贴、粮食直补、农机具购置补贴等一系列农业补贴政策,初步形成了农业补贴政策框架。这些措施极大地调动了广大农民种粮积极性,有力地推动了粮食生产的恢复发展,基本实现了粮食增产和农民增收的政策目标。但由于中国农业补贴政策体系仍处于初创阶段,在实施过程中仍存在许多问题。首先对中国农业补贴政策的实施现状进行了分析。然后,基于对江西省的实地调查数据,运用Cobb-Douglas生产函数对中国农业补贴效果进行了定量研究。最后,提出完善中国农业补贴政策的对策建议。研究的主要结论是,中国农业补贴政策在实施过程中仍存在许多问题,如补贴政策目标的短视化、补贴方式不科学、补贴结构不合理、补贴机制不健全等,应针对以上具体问题调整农业补贴政策的具体实施方式。     

Deleted HTLV-I provirus in blood and cutaneous lesions of patients with mycosis fungoides.

Mycosis fungoides, a rare form of cutaneous T cell leukemia/lymphoma, is suspected of having a viral etiology on the basis of certain similarities to adult T cell leukemia, which is associated with human T cell leukemia/lymphoma virus type I (HTLV-I) infection. Cell lines were established from peripheral blood mononuclear cells (PBMC) of an HTLV-I-seronegative patient with mycosis fungoides. DNA hybridization analysis revealed the presence of HTLV-I-related sequences with unusual restriction endonuclease sites. Sequence analysis of subcloned fragments demonstrated the presence of a monoclonally integrated provirus with a 5.5-kilobase deletion involving large regions of gag and env and all of pol. Additional evidence for the presence of deleted proviruses was found by polymerase chain reaction (PCR) amplification of DNA from cutaneous lesions of five other HTLV-I-seronegative patients. The findings suggest that HTLV-I infection may be involved in the etiology of at least certain cases of mycosis fungoides.     

棉蚜对不同类型杀虫剂的抗性发生规律

用溴氰菊酯、久效磷、灭多威及硫丹４种杀虫剂以浸渍法分别累代处理敏感棉蚜，选育至１６代，棉蚜对溴氯菊酯的抗性倍数达６７１９倍，对灭多威，久效磷及硫丹的抗性倍数分别为１９．９、１０．７和８．５倍。用计算机模拟预测棉蚜对４种药剂的抗性发展速度，若用上述４种药剂连续选育３２代，则棉蚜对溴氰菊酯、灭多威，主效磷及硫丹的抗药性将分别达６０７２１．７、２７９．３、１６．９０及６９．２倍。     

Limit of T cell tolerance to self proteins by peptide presentation

Cytotoxic T lymphocytes (CTLs) recognize foreign peptides bound to major histocompatibility complex (MHC) class I molecules. MHC molecules can also bind endogenous self peptides, to which T cells are tolerant. Normal mice contained CTLs specific for self peptides that were from proteins of ubiquitous or tissue-restricted expression. In vivo, these endogenous self peptides are not naturally presented in sufficient density by somatic cells expressing MHC class I molecules. They can, however, be presented if added exogenously. Thus, our data imply that CTLs are only tolerant of those endogenous self peptide sequences that are presented by MHC class I-positive cells in a physiological manner.     

悬栅消能率的投影寻踪回归数值模拟及检验

应用投影寻踪回归技术，对非正态、非线性悬栅消能率实验数据，用1／5数据建模拟合，4／5数据留做预留检验，拟合合格率92％，预留检验合格率92％，并与激光测速得出的消能率及原型观测的消能率完全吻合。