The distributions of Chinese yak breeds in response to climate change over the past 50 years

The effects of prior climate change on yak breed distributions are uncertain. Here, we measured changes in the distributions of 12 yak breeds over the past 50 years in China and examined whether the changes could be attributed to climate change. Long‐term records of yak breed distribution, grey relational analysis, fuzzy sets classification techniques and attribution methods were used. Over the past 50 years, the distributions of several yak breeds have changed in multiple directions, mainly shifting northward or westward, and most of these changes are related to the thermal index. Driven by climate change over the past years, the suitable range and the distribution centers of certain yak breeds have changed with fluctuation and have mainly shifted northward, eastward or southward. The consistency of observed versus predicted changes in distribution boundaries or distribution centers is higher for certain yak breeds. Changes in the eastern distribution boundary of two yak breeds over the past 50 years can be attributed to climate change.     

基于最大熵模型预测小火蚁在我国的适生区

小火蚁是中国大陆新发现的重要外来入侵害虫, 目前对该虫的传入来源和在我国的适生区范围尚不明确?为明确我国小火蚁适生区范围, 有效防控该虫在我国的扩散和蔓延, 本研究通过该虫全球已有的分布数据, 采用最大熵模型对其适生区进行了预测?研究表明, 最大熵模型预测小火蚁适生区精度较高?预测结果显示, 我国小火蚁的潜在适生区主要分布于南方, 其中, 高适生区分布在台湾?海南?云南南部边境?广西西南局部?福建西南部?广东南部及其沿海地区?预测结果与该物种现有地理范围的生态条件一致?年降水量对小火蚁的适生性影响最大, 理论年降水量为2 040 mm时小火蚁分布的概率最高?随着全球气候变暖, 未来我国小火蚁的适生区有向北扩大的趋势, 但主要适生区还是以南方为主?     

基于MaxEnt模型预测梨火疫病菌的潜在地理分布

为探究梨火疫病菌解淀粉欧文氏菌Erwinia amylovora在全球的潜在地理分布,基于其全球分布数据和筛选得到的环境变量,利用MaxEnt模型对其在当前气候和未来气候条件下的潜在地理分布进行预测,并利用刀切法和皮尔逊相关性分析法筛选对梨火疫病菌分布有重要影响的环境变量。结果显示,对梨火疫病菌分布有重要影响的环境变量包括2月平均最高温度、1月平均降水量、7月平均最低温度、温度变化方差、昼夜温差月均值和7月平均降水量,表明春季和夏季的温度和降水对梨火疫病菌的分布有较大影响。在当前气候条件下,梨火疫病菌在全球的适生区分布较广,适生区总面积达到5.58×10⁷ km²,且高适生区主要分布在北美洲沿海地区、地中海沿岸和亚洲中部及东部的部分地区;梨火疫病菌在我国的适生区总面积为7.36×10⁶ km²,占全国陆地总面积的76.70%;在未来气候SSP126和SSP585情景下,梨火疫病菌在全球的适生区总面积分别为5.52×10⁷ km²和5.24×10⁷ km²。表明梨火疫病菌对我国大部分地区有潜在威胁,应加强监测与防控。     

中国草地固碳减排研究现状及其建议

随着经济的快速发展,温室气体的排放量不断增加,加之人类对自然资源的利用强度逐渐增加,导致全球生态系统的固碳能力减弱,大气中的温室气体浓度达到新高,所造成的温室效应已经成为国际社会普遍关注的重大全球性问题。中国草地碳汇资源得天独厚,发展草原碳汇经济成为履行国际承诺、打造碳汇新经济、建设美丽中国的重要载体。综述中国草地固碳减排现状及其影响因素,包括草地碳汇和家畜生产减排研究、气候变化背景下的草地碳汇、人工草地建设等方面,并提出中国草地固碳减排发展建议,以期为中国实现碳达峰、碳中和及草地固碳减排的贡献提供理论基础,为推动我国社会高质量发展、创造高品质生活提供坚实的技术支撑。     

Optimality Conditions for Nonsmooth Extremum Problems in Topological Vector Spaces

Some new concepts of coneD_s convexity,coneD-s quasiconvexity,cone D-s pseudoconvexity,s right derivative of vector value mapping are proposed;and their related properties are discussed;the optimality necessary conditions and sufficient conditions for constrained extremum problem(VP)involving in cone D-s convex mapping are extablished;the relation between local optimal solution and global optimal solution;as well as the relation between weakly efficient solution and efficient solution for (VP) are derived;the corresponding results generalize the related results of classic convex programming.     

Experimental Study on the Deformation Characteristics of Fine-Sandstone Under the Loading and Unloading Conditions

The deformation characteristics of the fine-sandstone is studied under the loading and unloading conditions at the three different deformation-rates and the two different stress-levels. The experimental results show that there is really the plastic-loop in the deformation curve for the loading deformation curve is different from the unloading deformation curve. But the plastic-loop is nearly unchangeable since the second circulate loading. The residual-deformation is be almost zero since the second circulate loading, and that the slope of the deformation curve increases as the deformation-rate increases, and that the residual-deformation increases as the stress-levels increases.     

The Feasible Control for the Day-operation of the Three-Gorge Cascade Hydropower Station

The feasible control problem is presented for the day-operation of the Three-Gorge Caseade Hydropower Station. The significance of the problem is explained. Basic propetties ofthe problem and the approaches to study it are discussed. Two methfods are given for solving theproblem. which are calculus of variation and linear programming. In the former. the Euler equationwith time-lag and the generalised two-point boundary conditions are obtained and the correspondingpractical implication is interpreted. In the latter. the rationality for the discrete model is exptainedand the computalional details are given for the implement software. some questions which should bepaid much attentfon and the corresponding propeels are prasented based on the numerical results andtheoretical analysis     

Evolvement of Plastic-loop of Fine-sandstone Under the Loading and Unloading Conditions

The deformation characteristics and the plastic-loop of the fine-sandstone is studied under the loading and(unloading) condition at the three different deformation-rates and the two different stress-levels,the results show: 1) There is really the plastic-loop in the deformation curve for the loading deformation curve is different form the unloading deformation curve.But the plastic-loop is nearly unchangeable since the second circulate loading.2) There is different for every imitational parameter between the first deformation curve and the second deformation curve at the different stress-levels and the different deformation-rates,but every imitational parameters become more and more invariable gradually since the second circulate curve.3) With the change of the deformation-rates and stress-levels,the imitational(parameters) will change with it.4) The imitational parameters are different for loading section and unloading section of the fine-sandstone deformation curve at the same circulate curve under the same deformation-rate and stress-level.     

胶东半岛丘陵区典型流域气温-降

利用大沽夹河流域1966~2003年各水文站逐年、月气温和降水实测资料，采用线性倾向估计和Mann-Kendall法，对流域气候变化趋势的年季特征及突变性进行了分析。结果表明，（1）近40年来，大沽夹河流域年平均气温整体呈上升趋势，降水呈下降趋势，气候倾向率分别为0.20℃/10a和-42.17mm/10a。（2）春、夏、冬三季平均气温均呈上升趋势，秋季呈下降趋势。春、冬季的气温倾向率大于全年且冬季高于春季（分别为0.216和0.583℃/10a），夏季的气温倾向率（0.01℃/10a）小于全年；各季平均降水的变化趋势与年降水量变化趋势基本相似，整体亦呈减少趋势，但减少的幅度均明显小于全年平均降水。其中，夏秋季下降趋势较快，春冬季较慢，倾向率分别为-21.76、-15.52、-2.52和-2.25mm/10a。（3）除冬季外，各季及年平均气温均在1972年左右发生突变。其中，夏季在1994年左右发生第二次突变，秋季突变次数相对较多；降水的突变多发生在1970s和1980s初。