Soil properties associated with vegetation patches in a Pinus ponderosa —bunchgrass mosaic

Since Euro-American settlement, fire exclusion and other factors have dramatically altered interior western coniferous forests. Once open and parklike, present-day structure in many southwestern Pinus ponderosa forests consists of dense stands of young, small-diameter trees, with small patches of larger, old trees, and relict open bunchgrass areas. Our objectives were to assess differences in soil properties associated with these different vegetation patches. We examined soil morphological characteristics, pH, organic C concentration, total N concentration, C:N ratio, and phytolith concentration from profiles within 6 transects (18 soil pedons) crossing patches of dense stands of small diameter trees, patches of old-growth trees, and open grassy areas. Results indicate that old-growth plots had significantly lower A horizon pH and thicker O horizons than grass plots. In general, we found vegetation patches had statistically similar C and N concentrations and C:N ratios for A and B horizons; however, C in the A horizon was positively correlated with O horizon accumulation ( r 2 = 0.79). Greater accumulation of organic C in the A horizon of forested areas contrasts with commonly reported results from mesic, mid-continental prairie-forest ecosystems but is typical for many arid, semiarid, and humid savanna ecosystems. Phytolith concentration was similar among old-growth pine, dense younger pine, and open grassy plots; the lack of a spatial pattern in phytolith distribution could indicate that grass cover was more spatially continuous in the past. Additionally, this interpretation is consistent with current theories regarding historical vegetation change in these forests.     

中国养老政策的演进及智慧社会下居家养老的发展

 人口老龄化已经成为世界各国、各地区社会经济发展面临的重要问题。中国从2001年步入老龄化社会,提升老龄群体生活质量对于全面实现小康社会意义重大,也是促进中国城镇化健康发展的需要。梳理了中国20世纪80年代以来养老政策和实践的演进路径,强调了居家养老既要符合中国社会经济发展的特征,也要满足老龄群体的生活需求;鉴于中国社区的养老服务设施供给仍然滞后于老龄化发展的现状,探讨了在智慧社会下,通过信息化策略（虚拟空间）与可步行邻里环境（实体空间）,提升已有养老服务设施的服务覆盖面和质量、构建老龄群体的智慧社区生活模式、促进居家养老服务的时空匹配、提升居家养老服务的质量水平等策略。     

Versuche zur biologischen Bestimmung der Sedimentationskonstanten kleiner neurotroper Viren in der präparativen Ultrazentrifuge «ZF 3»

Summary An attempt is made to determine the sedimentation constant by means of biological assay in animal viruses. A new type of electromagnetic high speed centrifuge (Type ZF 3) was used for this purpose. An essential feature of this model is that the entire volume for assay is included in one single cell positioned at an angle of 90° to the axis of rotation. The murine EMC virus was used to show that the centrifuge is suitable for the biological determination ofS-values, in spite of the fact that the gravitational field in the cell is inhomogeneous and that the cell walls are not adapted to the radial migrational direction of the centrifuged particles.     

Thermal characteristics of montain lion dens

We used radiotelemetry and searched with a trained hound to locate the dens of 3 recently parturient mountain lions ( Felis concolor ). These dens were located in dense riparian vegetation along the same stream in the bottom of a steep canyon. We monitored circadian temperatures of 2 dens at 1-h intervals and compared them to ambient temperatures recorded simultaneously. We found mountain lion dens to effectively moderate high ambient temperatures, but these dens failed to provide a thermal advantage at the lowest ambient temperatures recorded in this investigation. We conclude that mountain lion dens provide effective protection from thermal maxima for young, immobile kittens.     

美国《科技与未来城市报告》对中国智慧城市建设的启示

 分析美国《科技与未来城市报告》智慧城市建设中的交通、能源、建筑与住房、水资源、城市农业及城市制造业6个重点领域表明,智慧城市的建设是以信息通信技术为引导,在城市不同领域且不断应用及持续发展过程;美国智慧城市建设的经验,是以城市片区为主体的试验单元,构建了信息、软件、结果、最佳实践的全国共享网络平台,重视联邦政府的引导和协调功能;探讨了美国《科技与未来城市报告》中智慧城市建设对中国城市建设的启示,指出当前智慧城市建设暴露出重投资轻管理、重技术轻人文关怀、重复建设与资源浪费等问题;建议中国在智慧城市建设中应注意,智慧城市的建设不等同于信息基础设施的建设、要依托政府打造中国智慧城市共享网络平台、应当充分发挥社会各方（学界、市场、市民）创新的积极性、需要国家政府统一协调引导及多范畴支持这4方面的内容。