关于依法保障和促进农村改革、发展与稳定的探索

农村的改革、发展与稳定，从根本上说涉及三个基本问题：一是农业经济的改革、发展与稳定；二是农民生活的保障和改善；三是农材精神文明水平的提高。这三个方面是相互依赖、相辅相成的。依法保障和促进农村的改革、发展与稳定，最关健的问题就是要将这三个方面的工作全面纳入法制的轨道。     

Domain movement in gelsolin: a calcium-activated switch

The actin-binding protein gelsolin is involved in remodeling the actin cytoskeleton during growth-factor signaling, apoptosis, cytokinesis, and cell movement. Calcium-activated gelsolin severs and caps actin filaments. The 3.4 angstrom x-ray structure of the carboxyl-terminal half of gelsolin (G4-G6) in complex with actin reveals the basis for gelsolin activation. Calcium binding induces a conformational rearrangement in which domain G6 is flipped over and translated by about 40 angstroms relative to G4 and G5. The structural reorganization tears apart the continuous beta sheet core of G4 and G6. This exposes the actin-binding site on G4, enabling severing and capping of actin filaments to proceed.     

利用愈伤组织培养和茎尖培养去除甘蔗花叶病毒

用甘蔗心叶愈伤组织和茎尖组织培养进行花叶病脱毒，供体发病率为１００％，而愈伤组织培养和茎尖培养后代的发病率分别为０和４．６％．本文还就分蘖数、有效茎数、株高、茎径和锤度等进行了剖析，并采用主成分分析法对群体进行综合评价，作为选种的理论依据．     

Daylight time-resolved photographs of lightning

Lightning dart leaders and return strokes have been recorded in daylight with both good spatial resolution and good time resolution as part of the Thunder-storm Research International Program. The resulting time-resolved photographs are apparently equivalent to the best data obtained earlier only at night. Average two-dimensional return stroke velocities in four subsequent strokes between the ground and a height of 1400 meters were approximately 1.3 x 10(8) meters per second. The estimated systematic error is 10 to 15 percent.     

Southern Ocean iron enrichment experiment: carbon cycling in high- and low-Si waters

The availability of iron is known to exert a controlling influence on biological productivity in surface waters over large areas of the ocean and may have been an important factor in the variation of the concentration of atmospheric carbon dioxide over glacial cycles. The effect of iron in the Southern Ocean is particularly important because of its large area and abundant nitrate, yet iron-enhanced growth of phytoplankton may be differentially expressed between waters with high silicic acid in the south and low silicic acid in the north, where diatom growth may be limited by both silicic acid and iron. Two mesoscale experiments, designed to investigate the effects of iron enrichment in regions with high and low concentrations of silicic acid, were performed in the Southern Ocean. These experiments demonstrate iron's pivotal role in controlling carbon uptake and regulating atmospheric partial pressure of carbon dioxide.     

Direct Determination of Grain Boundary Atomic Structure in SrTiO3

An atomic structure model for a 25 degrees [001] symmetric tilt grain boundary in SrTiO(3) has been determined directly from experimental data with the use of high-resolution Z-contrast imaging coupled with electron energy loss spectroscopy. The derived model of the grain boundary was refined by bond-valence sum calculations and reveals candidate sites for dopant atoms in the boundary plane. These results show how the combined techniques can be used to deduce the atomic structure of defects and interfaces without recourse to preconceived structural models or image simulations.