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Wes Jackson 《Public Library Quarterly》2013,32(1):76-79
In this letter, the director of the Institute, Wes Jackson, contrasts the agriculture he sees in a nearby cultivated field versus the agriculture that Americans need to sustain farm land and the human food supply. Jackson suggests that “a new agriculture” is the only way we will improve the quality of our land and increase the reliability of our food supply. 相似文献
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有害生物的生态调控一直是作物病虫害预防与治理的重要前沿科技领域。目前有害生物生态调控研究已由单一的农田拓展到区域性农田景观的空间范围。研究区域性农田景观中格局特征和人类活动对病虫害和天敌种群动态影响,不仅在病虫害生物防治的实践中有重要意义,而且对于揭示人类活动对生物多样性结构与功能的影响,阐明区域性农田景观中生物多样性整合、维持机理有重大的理论意义。作物病虫害的导向性防控——生物间信息流与行为操纵,最终需要体现和落实在特定的地理区域空间范围内,参与到粮食作物生产与病虫害生态管理活动过程中。文章主要阐述区域性农田景观中格局特征与人类种植活动对昆虫的生态学效应,并提出构建基于区域性农田景观多元化的有害生物生态调控体系。 相似文献
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《International Journal of Information Management》2016,36(1):44-59
Platform-centric ecosystems run by Apple, Google, Microsoft, etc. enable the companies to magnify the values of their products and services on an unprecedented scale, by harnessing third-party add-on software such as mobile apps. Despite the importance, however, there is a dearth of empirical research that investigates how third-party developers’ continued participation is actually determined. This paper examined two different mechanisms increasing dedication to a platform and constraining exit from the platform, respectively. Specific factors in each mechanism and their casual relationships were tested and discussed in the context of Apple’s mobile platform. 相似文献
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Megan Powell Cuzzolino Tina A. Grotzer M. Shane Tutwiler Eric W. Torres 《科学教学研究杂志》2019,56(8):1083-1105
Agent-oriented pedagogies have been used in teaching concepts related to complex systems dynamics. However, little research has systematically explored the role of a strong agency-oriented focus on understanding of complex, dynamic ecological systems. This study analyzed seventh graders' (n = 216) explanations of a complex ecological scenario. The findings show that students were more likely to generate agentive than nonagentive explanations and students who adopted an agentive framing were least likely to understand the complex causal dynamics of two environmental scenarios, eutrophication in a pond and acid rain in a forest. Furthermore, students' initial inclination toward agency-oriented explanation on the assessment was predictive of their performance on a postassessment following an instructional opportunity to learn about ecosystems dynamics; a strong agency orientation corresponded to less complex interpretations of the dynamics of the ecosystems. The results suggest that a strongly agentive perspective may limit students' ability to learn complex systems dynamics and that the pedagogical advantages of agent-based approaches may not be without limitations. 相似文献
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作者对西部干旱地区"四河四域"(黄河宁蒙段、石羊河、黑河、塔里木河)的水问题进行了调研,涉及其上中下游的历史背景与现状,包括水资源、水灾害、水生态、水污染;水工程、节水技术、水景观;水制度、水经济、水伦理、水美学,认为:西部干旱地区水问题主要不是自然原因,而是人类因素造成的。根据"生态水利"观,就广义"水资源"概念,自然生态用水定额,干旱地区的经济结构和城镇建设模式,恢复、保护和创造性利用内陆河下游自然生态系统,节水行动和技术的新方向,与干旱地区自然环境和生态特点相适应的水利工程,完备水制度以及人工调水等8个方面,提出了建议。 相似文献
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《Endeavour》2020,44(1-2):100719
The Puerto Rico Trench is a deep oceanic subduction zone that runs parallel with the northern coasts of Puerto Rico and the Dominican Republic. It is the deepest place in the Atlantic Ocean with a maximum depth of approximately 8400 m. Discovered by the HMS Challenger Expedition in 1875, the depth of the trench increased multiple times in the ensuing 100 years with the onset of sonar usage. It is perhaps unique among the world’s deep trenches in that a series of unrelated but equally pioneering expeditions captured the true biological and geological characteristics of one of the deepest places in the world, observations that are still highly relevant today. Multiple deep water trawling campaigns and surveys using drop cameras and exploratory dives in a deep diving submersible provided great insight into the morphology of the trench, the types of habitat within the trench, the substrate, the food supply, and the diversity of species that inhabit these extraordinary depths. Many of these accounts are obscure and disparate, yet combined bear a remarkable similarity to recent work in other trenches. These unique and insightful accounts are collated and retold here alongside recent and comparable findings to contextualise these discoveries, prevent them from being forgotten, and keep the efforts of those involved to remain relevant as we continue to explore the deepest places of the world’s oceans. 相似文献
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ABSTRACTThis paper reflects on approaches to collaborative knowledge exchange projects between UK universities and the creative economy. It develops a preliminary account of cultural ecology as a systematic approach to producing impact in the creative economy. It argues that such an approach is a powerful way to aggregate micro-businesses and small and medium sized enterprises in a meaningful network of new relationships. The paper uses social network analysis software to begin to visualise the pattern of relationships that constitute the ecosystem. The paper reports on the work of the Research and Enterprise for Arts and Creative Technologies Hub, one of four Knowledge Exchange Hubs for the Creative Economy established by the Arts and Humanities Research Council. 相似文献