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- Genre: Doctoral Dissertation
- Creators: Gu, Bin
Hydrology and biogeochemistry are coupled in all systems. However, human decision-making regarding hydrology and biogeochemistry are often separate, even though decisions about hydrologic systems may have substantial impacts on biogeochemical patterns and processes. The overarching question of this dissertation was: How does hydrologic engineering interact with the effects of nutrient loading and climate to drive watershed nutrient yields? I conducted research in two study systems with contrasting spatial and temporal scales. Using a combination of data-mining and modeling approaches, I reconstructed nitrogen and phosphorus budgets for the northeastern US over the 20th century, including anthropogenic nutrient inputs and riverine fluxes, for ~200 watersheds at 5 year time intervals. Infrastructure systems, such as sewers, wastewater treatment plants, and reservoirs, strongly affected the spatial and temporal patterns of nutrient fluxes from northeastern watersheds. At a smaller scale, I investigated the effects of urban stormwater drainage infrastructure on water and nutrient delivery from urban watersheds in Phoenix, AZ. Using a combination of field monitoring and statistical modeling, I tested hypotheses about the importance of hydrologic and biogeochemical control of nutrient delivery. My research suggests that hydrology is the major driver of differences in nutrient fluxes from urban watersheds at the event scale, and that consideration of altered hydrologic networks is critical for understanding anthropogenic impacts on biogeochemical cycles. Overall, I found that human activities affect nutrient transport via multiple pathways. Anthropogenic nutrient additions increase the supply of nutrients available for transport, whereas hydrologic infrastructure controls the delivery of nutrients from watersheds. Incorporating the effects of hydrologic infrastructure is critical for understanding anthropogenic effects on biogeochemical fluxes across spatial and temporal scales.
本研究聚焦冷链物流产业园金融服务助力冷链物流企业发展问题,主要研究内容包括:第一,基于产融结合理论,梳理冷链物流企业与产业园之间关系,从供需两侧探索冷链物流企业和产业园的金融服务的范围、类型和特点。第二,基于平台理论,构建冷链物流企业采纳产业园金融服务的研究模型,探索金融服务影响冷链物流企业的经营因素,分析冷链物流企业采纳产业园金融服务的因素和途径。第三,基于信息不对称理论,关切信息技术支持和知识分享在冷链物流企业采纳产业园提供金融服务过程中的调节作用。同时,梳理产业园提供金融服务可能面临哪些风险,制订冷链物流企业入驻园区的标准,防范风险。
本文运用实证研究方法,通过对国内18家冷链物流相关的产业园、物流园、冷链物流、商贸流通、金融等企业实地考察和专家访谈基础上,拟定问卷并对268家企业进行调查收集数据,使用结构方程模型进行假设检验。研究发现:金融服务的有形性、可靠性、移情性、经济性对冷链物流企业采纳产业园金融服务影响显著,而响应性的影响不显著。同时
信息技术支持和知识共享的调节作用不显著。最后,针对产业园吸引冷链物流企业提供金融服务、冷链物流企业采纳产业园金融服务的风险,提出防范策略措施。