人才资源向人才资本转变的大市场--中美技术贸易市场

中美两国技术贸易市场开发前景良好,双方具有互补性.只要两国从大局出发,增进交流与合作,它必将是21世纪中美两国的大市场.     

Effects of Population Size on Singing Behavior of a Rare Duetting Songbird

Although the genetic and ecological effects of population declines in endangered species have been well studied, little is known of the social consequences. Changes in signaling behavior may result in disrupted communication and affect both reproductive and conflict‐resolution activities. The North Island Kōkako (Callaeas wilsoni) is an endangered, duetting (i.e., alternating, coordinated singing by mated pairs) songbird endemic to New Zealand temperate rain forests. Scattered populations (approximately 1500 individuals in 13 surviving and 11 translocated populations) in isolated conservation areas of different sizes have been rescued from extirpation and are currently recovering. We examined key song attributes of the Kōkako to assess whether population size or growth rate are related to song complexity, the reduction of which may compromise effective communication. We analyzed song repertoire size and phrase‐type sharing (i.e., Jaccard index of similarity), vocal performance (singing rates, song switching rates, and diversity of phrase types), and song syntactical characteristics (i.e., unpredictability in sequences of phrase types) in surviving and translocated populations (populations of approximately 19–250 territorial individuals). Population size was positively correlated with a population's song repertoire, song diversity, and switching of song phrase types and negatively correlated with shared phrase types and variation in syntactical structure of songs. Population growth rate correlated positively with pair repertoire size, population repertoire size, and singing rates during song bouts. As for solo‐singing species in fragmented landscapes, songs in the fragmented populations of Kōkako appear to be undergoing microevolution as occurs in island colonization events. Our results suggest that vocal changes in small populations could affect population establishment and growth, particularly in multiple‐source translocations. We believe measurement of vocal behavior could be used as a supplement to periodic population censuses to allow more frequent monitoring of population size. Efectos de la Conducta de Canto sobre el Tamaño Poblacional de una Ave Canora Rara     

基于SWAT模型以北运河上游流域氮负荷削减为重点的山水林田湖草修复措施配置研究

利用SWAT模型对北运河上游流域进行模拟分析,评估了 4类10项24种山水林田湖草生态治理措施对氮负荷的削减效果及山水林田湖草系统治理措施效果.结果表明,径流率定及验证纳什系数(NSE)＞0.50,相对误差(PBIAS)≤±40％,泥沙量、氮负荷总体PBIAS≤±40％,SWAT模型对径流、泥沙、总氮的模拟值与实测值展...     

北运河上游合流制管网沉积物的月变化与污染物赋存特征

合流制管网沉积物是溢流污染的重要来源,明确其月变化和污染物赋存特征,有助于管网沉积物控制和溢流污染负荷削减.本研究现场调查了北运河上游合流制管网沉积物的月变化和污染物赋存特征,结果表明,管网沉积物的粒径分布为大颗粒(10目)、10～40目颗粒和细颗粒(60目)分别占36％、～50％和15％(质量比).管网沉积物在干季初...