国外乡村地理关系研究范式进展与启示

随着区域一体化政策和信息、交通等设施的推进,乡村地区被纳入更为广泛的要素流通与经济过程中,乡村地区被内、外经济社会多重联系重新定义。论文通过回顾西方发达国家乡村地理关系范式研究进展,重点探讨了乡村地区能否通过加强外向联系来削弱其地理区位边缘性这一核心问题,同时探讨了关系研究范式在中国乡村地理研究中的适用性,并试图构建起适应中国国情的乡村关系地理研究框架。西方乡村地理学者提出了关系的研究范式以适应乡村地区新的发展背景,在关系视角的研究语境中,社会经济活动中的参与主体被当作真正的研究对象,关注参与主体间各类“流”要素及其关系;同时,距离的概念被重新定义,地理空间呈现虚、实交互的特征,关系距离是对基于位空间的乡村研究的补充;此外,关系资本、弱关系和嵌入性等“关系”概念重新定义了乡村社会经济的作用过程。研究发现,地理区位与地方性特征仍然是乡村产业发展及参与外部竞争最重要的资本,但以通信、交通等设施为代表的“硬”环境的改善对弥补乡村区位劣势的边际效益逐渐降低。因而现阶段乡村振兴战略的推进需要从制度空间、学习空间、“非正式”社交网络等“软”环境的建设着手,促进信息、技术和资本等“流”要素的移动,进而推动乡村产业和功能的发展。     

国内村域尺度乡村转型发展与重构的现状述评及展望

乡村转型发展与重构是解决乡村衰落的重要抓手,乡村振兴是国家破解新时代“三农”问题的重大战略部署。论文通过对现有乡村发展相关文献的梳理与分析,从研究范式、演进过程、机理探析和路径探索等4个方面总结了国内乡村转型发展与重构的研究现状及展望。发现乡村转型发展与重构研究具有多学科交叉的研究视角、多元融合的研究内容、综合多样的研究方法与手段。未来需重视不同类型村域转型发展与重构中乡土文化的研究,加强欠发达区不同类型村域转型发展与重构的实证研究,深化多学科理论与方法的综合研究,优化不同发展模式下乡村转型发展与重构的路径。     

Abrupt shifts in the Indian monsoon during the Pliocene marked by high-resolution terrestrial records from the Yuanmou Basin in southwest China

A 650-m-thick sequence of fluvio-lacustrine sediments from the Yuanmou Basin in southwest China was analyzed at 20-cm intervals for grain-size distribution to provide a high-resolution terrestrial record of Indian summer monsoon variations during the Pliocene. The concentrations of the clay and clay-plus-fine-silt fractions are inferred to reflect the water-level status of the lake basin related to the intensity of the Indian summer monsoon and high concentrations reflect high lake levels resulting from the intensified summer monsoon. The frequency of individual lacustrine mud beds is considered to reveal the frequency of the lakes developed in the basin associated with the variability of the Indian summer monsoon and an increased frequency of the lakes reveals an increased variability of the summer monsoon. The proxy data indicate that the Indian summer monsoon experienced two major shifts at 3.57 and 2.78 Ma and two secondary shifts at 3.09 and 2.39 Ma during the Pliocene. The summer monsoon displayed a general trend of gradual intensification during the period of 3.57–2.78 Ma, coeval with an accelerated uplift of the Tibetan Plateau, implying a close link between the monsoon intensification and the plateau uplift. At 2.78 Ma, the summer monsoon was markedly weakened, synchronous with the formation of extensive Northern Hemisphere ice sheets, denoting a quick response of the monsoon regime to the Northern Hemisphere glaciation. The variability of the summer monsoon decreased at 3.09 Ma and increased at 2.39 Ma, presumably suggesting that variations of the Indian monsoon would be modulated by the initiation and periodic fluctuations of ice-sheet covers in Northern Hemisphere high latitudes.     

A closer look at regime shifts based on coastal observations along the eastern boundary of the North Pacific

At least six regime shifts have been reported in the North Pacific since 1920. They occurred in 1925, 1939, 1946, 1976–1977, 1989 and 1999. The major change in 1976–1977 corresponds to a regime shift that is now widely accepted as a canonical event since it had a significant impact on virtually all climatic and ecosystem indicators. We seek to determine if daily sea surface temperature (SST) from Pacific Grove, in central California, and Scripps Pier, in southern California, and coastal observations from several other locations along the west coast of North America can be used to detect and resolve these events. Cumulative sums (CUSUMs) were initially calculated to enhance the detection process. The CUSUM trajectories during the 1976–1977 event at Pacific Grove and Scripps Pier were distinctive, highly correlated, and in phase. The turning point patterns from this event were then used to search for other events that have been reported since 1920. Turning point patterns very similar to the 1976–1977 event were detected in 1946 and 1989. The events in 1925 and 1939 were generally similar, but the CUSUM patterns for the event in 1999 departed significantly from the other events. Further examination of the 1976 and 1989 events revealed inflection points in the CUSUMs near the beginning and end of each transition that correspond to critical values or extrema in the original data. The inflection points and/or critical values provide an improved basis for determining the duration of these events.     

<Emphasis Type="Italic">An Inconvenient Truth</Emphasis> and the scientists

An Inconvenient Truth provides an opportunity to examine the differences between scientific statements and the mixed statements made by politicians. The Gore movie is a powerful example of the latter. There are some inaccuracies and exaggerations in the film, but on the whole it represents mainstream scientific views on global warming. This essay looks into the state of the art of climate change research including its scientific underpinnings. Climate science is in a state of ‘normal science’ as discussed by Kuhn. There is a large body of scientists who are adherents to the paradigm and there does not appear to be any serious alternative at this time.     

Spectral analysis of the 3B flare on September 19, 1979: asymmetries and shifts of metallic lines

The asymmetries and Doppler shifts of metallic lines of the 3B flare on September 19, 1979 are investigated in this paper. The results show that: (1) red asymmetries dominate in strong metallic lines, but blue asymmetries also exist in some weak lines; (2) the maximum of the line asymmetry always precedes the maximum of the line intensity; (3) the blue asymmetry occurs generally in the early phase, and can occasionally turn to a red one in the later phase; and (4) the line center has no obvious shift, regardless of the line asymmetry. It is proposed that, the mass motions around the temperature minimum region caused by the impulsive heating or the propagation of the chromospheric condensation can explain these observational results. The study on metallic lines has an auxiliary help for understanding the dynamic process in the lower atmosphere of solar flares.     

International politics must be considered together with climate and fisheries regulation as a driver of marine ecosystems

Seafood is an essential source of protein globally. As its demand continues to rise, balancing food security and the health of marine ecosystems has become a pressing challenge. Ecosystem-based fisheries management (EBFM) has been adopted by the European Union (EU) Common Fisheries Policy (CFP) to meet this challenge by accounting for the multiple interacting natural and socio-economic drivers. The CFP includes both the implementation of regulatory measures to EU stocks and the establishment of bilateral fisheries agreements with neighbouring countries, known as sustainable fisheries partnership agreements (SFPAs). While the effects of fisheries management regulations are well acknowledged, the consequences of the SFPAs on EU ecosystems have been commonly overlooked. Here we investigate the development of the Gulf of Cadiz marine ecosystem over the last two decades and found evidence of the impact of both policy interventions. Our findings reveal the effectiveness of regulatory measures in reverting a progressively degrading ecosystem, characterised by high fishing pressure and dominance of opportunistic species, to a more stable configuration, characterised by higher biomass of small pelagics and top predators after 2005. Knock-on effects of the EU-Morocco SFPA and climate effects were detected before 2005, resulting in increased purse seine fishing effort, lower biomass of pelagic species and warmer temperatures. This southern EU marine ecosystem has been one of the latest to introduce regulations and is very exposed to fishery agreements with neighbouring Morocco. Our study highlights the importance of taking into consideration, not only the effects of in situ fisheries regulations but also the indirect implications of political agreements in the framework of EBFM.     

可变类多光谱遥感图像分割

确定图像类别数是图像分割中的重要任务,在大多数分割算法中需由用户预先指定类别数。受地物目标及其分布的多样性、复杂性和未知性等因素的限制、对彩色遥感图像而言,人为确定其类别数非常困难。为此,提出了一种基于区域和统计的可变类分割方法,融合规则划分技术和R.JMCMC算法,利用规则划分将图像域划分成若干个规则子块,并假设每个规则子块内的像素服从同一独立的多值Gaussian分布;在此基础上南贝叶斯定理构建图像分割模型;利用ReversibleJump Markov Chain Monte Carlo(RJMCMC)算法模拟该模型,实现罔像类别数的自动确定及图像粗分割;为了进一步提高图像分割精度,设计精细化操作,对Worldview-2合成及彩色遥感图像和多光谱IKONOS图像进行可变类分割,实验结果表明,提出方法不仅能自动确定图像类别数,还可以较好地实现区域分割。本文方法较好地实现彩色遥感图像的可变类分割。     

面向重建规划的灾后资源环境承载能力应急评价范式

从国家重建规划对资源环境承载能力应急评价的应用需求出发,解析重大灾害事件发生后承载能力应急评价难点,初步构建在灾后资源赋存、环境容量、生态安全以及灾害风险多重约束下,资源环境承载能力应急评价的基本范式与技术流程,并提出未来灾后承载能力评价及研究重点。研究表明：针对评价周期短、涉及内容广、决策风险高、不确定性强、数据基础不足等特点与难点,需从地域功能预估与指标体系、单项要素评价与技术准则、综合集成评价与重建分区、人口容量测算与重建模式4个方面实施灾后应急评价。未来,建议从灾后资源环境承载能力评价关键阈值与参数研究,应急评价辅助支撑体系与规划衔接技术研究,灾后承载能力演化特征与弹性机理研究,青藏高原边缘地带及近邻山区等灾害高风险区的重点研究与超前应对,以及灾后应急评价及重建规划的工作协调与应用推广等方面,进一步深化灾后资源环境承载能力研究,提升未来应急评价快速化、规范化、精准化水平,为增强国家和地方政府灾后系统应对能力提供借鉴。     

微观视角下旅游情境人地关系的理论与经验

旅游现象与活动中的人地关系是旅游研究中的跨学科议题,但目前微观心理与行为视角下的旅游情境人地关系研究尚有不足。本文检视了旅游情境人地关系研究的特殊性和多元性,探究了微观视角下旅游情境人地关系研究的经验化路径,以旅游者行为意愿为例对人—地二元环境刺激促成人—地交互及行为反应的可能机制进行了理论推导和实证检验,并分析了上述理论与经验探讨对于旅游情境人地关系研究的启示。研究表明：① 旅游情境人地关系研究具有多元对象、层次、范式及方法论,存在4种主要情形和2种典型范式。② 心理—行为范式是拓展人地关系研究的重要方向,提炼具体问题和聚焦具体变量是微观视角下旅游情境人地关系研究经验化及本体论化的关键环节。③ 认知和情感形象、地方依恋、行为意愿等构成的经验模型是对人—地二元到人—地交互理论逻辑的一种刻画,为旅游者行为提供了一个可能的人地关系解释。④ 微观视角下旅游者行为意愿的形成经历了地的功能与人的情感两个向度环境刺激、地方依恋人地联结有机体、行为反应之间的传导过程。⑤ 微观视角下旅游情境人地关系研究需把握人地关系主题与旅游现象特性、完善多元尺度和范式、推进理论的经验化、注重方法的问题导向和理论意义。