农民协会的建立与完善

建立农民协会不仅受宪法保障,而且是实行民主政治、建立有限政府、构建农村市民社会、发展农村社会主义市场经济的需要。应通过准确定位,完善相关法律法规,加强自身建设等途径,推动农民协会的建立与完善。     

The 2010 Amazon drought

In 2010, dry-season rainfall was low across Amazonia, with apparent similarities to the major 2005 drought. We analyzed a decade of satellite-derived rainfall data to compare both events. Standardized anomalies of dry-season rainfall showed that 57% of Amazonia had low rainfall in 2010 as compared with 37% in 2005 (≤-1 standard deviation from long-term mean). By using relationships between drying and forest biomass responses measured for 2005, we predict the impact of the 2010 drought as 2.2 × 10(15) grams of carbon [95% confidence intervals (CIs) are 1.2 and 3.4], largely longer-term committed emissions from drought-induced tree deaths, compared with 1.6 × 10(15) grams of carbon (CIs 0.8 and 2.6) for the 2005 event.     

类最佳自相关序列偶的研究

首先提出D-最佳自相关序列偶的概念，然后在此基础上得出了类最佳自相关序列偶的定义。根据对序列一些变换进行的定义，研究了类最佳自相关序列偶的性质、存在的必要条件，运用这些性质和存在必要条件可以使类最佳自相关序列偶的搜索范围大大缩小，提高了对类最佳自相关序列偶搜索效率，也可以用已知的类最佳自相关序列偶构造出同长度的类最佳自相关序列偶。     

The ocean as a chemical system

This discussion may have given the feeling that the present composition of ocean water does not result just from blind chance. The composition may in the main be given by well-defined equilibria, and the deviations from equilibrium may be explainable by welldefined processes. However, much remains to be discovered by laboratory work and studies of the natural systems. For any discussion of equilibria between sediments and sea water to become really fruitful and decisive, one must achieve a much better separation of the various sediment phases than has been obtained hitherto. Equilibrium data for various silicate systems are highly desirable. Studies of various elements indicate that there are serious gaps in our knowledge of soluble species and of equilibrium constants for known species; equilibrium measurements in the ionic medium, sea water, are scarce and not too reliable. Obviously, better understanding of the system ocean plus air plus sediments and of its history will require close cooperation between geologists, biologists, and chemists of various specialties.     

The geological record of ocean acidification

Ocean acidification may have severe consequences for marine ecosystems; however, assessing its future impact is difficult because laboratory experiments and field observations are limited by their reduced ecologic complexity and sample period, respectively. In contrast, the geological record contains long-term evidence for a variety of global environmental perturbations, including ocean acidification plus their associated biotic responses. We review events exhibiting evidence for elevated atmospheric CO(2), global warming, and ocean acidification over the past ~300 million years of Earth's history, some with contemporaneous extinction or evolutionary turnover among marine calcifiers. Although similarities exist, no past event perfectly parallels future projections in terms of disrupting the balance of ocean carbonate chemistry-a consequence of the unprecedented rapidity of CO(2) release currently taking place.     

The ocean takes a deep breath

Deep convection is the major mechanism for replenishing oxygen in the deep interior of the world ocean, and its variability affects the use of atmospheric oxygen to monitor the global carbon cycle. Sensors mounted on autonomous floats allow this episodic breathing of the ocean to be monitored in near real time. The results suggest that the tools are available now to make oxygen a key parameter in marine global change research.     

抗旱玉米育种研究

干旱是当今乃至未来玉米生产的第一限制因素,进行玉米抗旱育种十分必要.在总结玉米抗旱育种常规方法的基础上,重点就抗旱育种的关键技术-干旱管理和第二性征选育以及选择指数在抗旱育种中的运用进行了具体阐述.干旱处理的时间、强度及一致性是干旱管理的关键因素;产量、每株穗数、雌雄花期间隔、叶片衰老率、雄穗大小、叶片卷曲度为有效的抗旱选育常用的第二性征.