乡村振兴视角下秦巴山区农村路网通达性评价与分区优化研究——以陕西省山阳县为例

交通是经济发展的命脉,路网通达性是衡量交通发展水平的有效评价指标。以位于秦巴山区的陕西省山阳县为例,采用网络分析、空间自相关与地理加权回归等方法,从分项评价、综合评价两方面研究农村路网通达性,并进行通达性分区;提取各区中对经济发展影响较大的分项因子,有针对性地提出了优化策略。结果表明:(1)山阳县路网通达性呈北高南低、由高通达性极核向外围递减的"核心—外围"空间分异特征。(2)通达性水平高的区域地形平坦,区内外交通条件优良,是山阳县的经济、政治及文化中心,对周边村镇有一定辐射带动作用。通达性水平低的区域区位偏远,地形复杂,经济发展滞后。(3)路网通达性水平与社会经济的相关系数在不同分区有空间异质性。最后,提出分区优化建议,以促进经济发展,助力乡村振兴。     

The Upper Paleolithic of the Russian steppe zone

The vast steppe area North of the Black Sea has been populated since the early Middle Paleolithic. The number of known sites dating to the Upper Paleolithic is increasing as research progresses, and today about 150 Upper Paleolithic sites have received some (although varied) degree of study. For a long time, the steppe zone was considered to have had a separate cultural-economic adaptation that differed drastically from that found in the periglacial province farther north. The difference was expressed in the specialization in bison hunting and in the very high mobility of the population. More recent archaeological research, described briefly in this article, presents a different picture: Subsistence was more varied, hunting was not limited to bison, and the settlement system indicates long periods of occupation of the sites. There were many local archaeological cultures, and study of the material remains indicates numerous contacts between the people of the steppe zone and those in Central Europe and the Caucasus and, by way of the Caucasus, with Western Asia.     

Fluid inclusion and stable isotope constraints on the genesis of the Jian copper deposit,Sanandaj–Sirjan metamorphic zone,Iran

The Jian copper deposit, located on the eastern edge of the Sanandaj–Sirjan metamorphic zone, southwest of Iran, is contained within the Surian Permo‐Triassic volcano‐sedimentary complex. Retrograde metamorphism resulted in three stages of mineralization (quartz ± sulfide veins) during exhumation of the Surian metamorphic complex (Middle Jurassic time; 159–167 Ma), and after the peak of the metamorphism (Middle to Late Triassic time; approximately 187 Ma). The early stage of mineralization (stage 1) is related to a homogeneous H₂O–CO₂ (XCO₂ > 0.1) fluid characterized by moderate salinity (<10 wt.% NaCl equivalent) at high temperature and pressure (>370°C, >3 kbar). Early quartz was followed by small amounts of disseminated fine‐grained pyrite and chalcopyrite. Most of the main‐ore‐stage (stage 2) minerals, including chalcopyrite, pyrite and minor sphalerite, pyrrhotite, and galena, precipitated from an aqueous‐carbonic fluid (8–18 wt.% NaCl equivalent) at temperatures ranging between 241 and 388°C during fluid unmixing process (CO₂ effervescence). Fluid unmixing in the primary carbonaceous fluid at pressures of 1.5–3 kbar produced a high XCO₂ (>0.05) and a low XCO₂ (<0.01) aqueous fluid in ore‐bearing quartz veins. Oxygen and hydrogen isotope compositions suggest mineralization by fluids derived from metamorphic dehydration (δ¹⁸O_fluid = +7.6 to +10.7‰ and δD = ?33.1 to ?38.5‰) during stage 2. The late stage (stage 3) is related to a distinct low salinity (1.5–8 wt.% NaCl equivalent) and temperatures of (120–230°C) aqueous fluid at pressures below 1.5 kbar and the deposition of post‐ore barren quartz veins. These fluids probably derived from meteoric waters, which circulated through the metamorphic pile at sufficiently high temperatures and acquire the characteristics of metamorphic fluids (δ¹⁸O_fluid = +4.7 to +5.1‰ and δD = ?52.3 to ?53.9‰) during waning stages of the postearly Cimmerian orogeny in Surian complex. The sulfide‐bearing quartz veins are interpreted as a small‐scale example of redistribution of mineral deposits by metamorphic fluids. This study suggests that mineralization at the Jian deposit is metamorphogenic in style, probably related to a deep‐seated mesothermal system.     

Looking Out to Look In: The Use of the Periphery in China's Geopolitical Narratives

Using a previous paper published in Eurasian Geography and Economics (Agnew, 2012) as a point of departure, an American geographer and specialist on China explores the role of the periphery (frontier, borderlands) in forging perceptions of China's place in the world. By presenting counter-narratives to the myth of a singular Chinese culture/ethnicity spreading inexorably from a Yellow River hearth region over five millennia, the author demonstrates how the Chinese have "looked out" (i.e., used a complex and seemingly alien frontier space) in order to "look in" (mark a "Chinese" identity as culturally homogeneous even when it was not). The paper examines how this process worked through time to repeatedly reinvent an unambiguous and knowable China from histories of intermixing, ambiguity, and spatial complexity. It contrasts a Mao-era perspective of a periphery marking the leading edge of an expanding and homogeneous Chinese culture with post-Mao and post-socialist narratives, which view the periphery more as a "contact zone" between China and its neighbors, where Han ethnicity and Chinese civilization alike are viewed as having absorbed external influences.     

The changing nature of the peri‐urban zone in Africa: Evidence from Dar‐es‐Salaam,Tanzania

Research on the peri‐urban zones of African cities since the mid‐1980s has focused around three main themes, these being peri‐urban agriculture as a survival strategy, debates about the relative efficiencies of peri‐urban agriculture, and the question of production priorities. Drawing on recent evidence from Dar‐es‐Salaam in Tanzania, this paper suggests that a combination of structural adjustment measures and the eased economic crisis in Tanzania has changed conditions, the result of which has been the increasing commodification of land in the peri‐urban zone during the 1990s. This has turned the peri‐urban zone more into a zone of investment and economic opportunity, rather than a zone of survival, with the result that the poorer urban groups are being increasingly excluded. A further complication concerns confusion arising out of current Tanzanian land law, and particularly the tensions between customary and statutory law.     

Ghogha: an Indo-Arabian Trading Post in the Gulf of Khambhat (Cambay), India

The ancient port of Ghogha is situated on the western bank of the Gulf of Khambhat, which has the highest tidal range in India, and the remains of the oldest civilization. Recent marine archaeological explorations in this area yielded many stone anchors. Most are of Indo-Arab type, and only one composite anchor was reported from Ghogha. An anchor similar to those found on the Chinese coast was found at Hathab. With the stone anchors from Ghogha was found a large quantity of glazed ware, suggesting a possible date for the anchors of the 10th to 14th century AD.
© 2010 The Author     

Chronicles of vadose zone diagenesis: cone‐shaped iron oxide concretions,Triassic Trujillo Formation,Palo Duro Canyon,Texas

Unusual cone‐shaped iron oxide concretions occur in the Late Triassic, lower fluvial sandstone member of the Trujillo Formation at Palo Duro Canyon in the Texas panhandle. In situ concretions are significant because they record both historical information about past processes that occurred within the geologic unit and present‐day information about the ability of the unit to conduct fluids. The dominant orientation of the concretions is cone‐apex up, body radiating down and out, with long axis perpendicular to bedding. Concretion morphologies are associated with the sedimentary texture and primary bedding structure of the host rock and the corresponding hydrologic regime (i.e. advection versus dispersion for iron‐transport behavior). Three lithofacies in the lower Trujillo member exhibit different cone forms. Field observations of cone orientation and morphology suggest vadose conditions for diagenetic precipitation of iron oxide cements, with timing potentially represented by the major pre‐Miocene unconformity.     

思想政治课教学心理误区分析与跨越走向设计

思想政治课教学的心理问题,应引起人们的高度重视;教学心理误区值得人们深刻反思。政治教师要有意识的应用教育学、心理学的原理于教学活动之中,努力创造良好的心理氛围,跨越心理误区,使思想政治课教学实现新的飞跃。     

The In Situ Preservation in the Unsaturated Zone: Results from Environmental Investigations at the ‘Schultz Gate’ Case Study in the Medieval Town of Trondheim,Norway

Medieval Trondheim is located on the eastern part of Nidarneset, a small peninsula formed by the river plain at the mouth of the River Nid on the southern shore of Trondheimsfjord. The topographic conditions for medieval Trondheim differ from those of the other Norwegian medieval towns (notably Bergen, Oslo, and Tønsberg), and the protected, historic part of Trondheim contains anthropogenic sediments which lie entirely within an unsaturated environment. A large proportion of these sediments contain wood and other types of organic material. The thickness of the anthropogenic sediments varies greatly from more than 4 m to less than 0.5 m, and they overlie well-drained alluvial sands and gravels. The Directorate for Cultural Heritage (Riksantikvaren) and the Norwegian Institute for Cultural Heritage Research (NIKU) have different roles in the management of cultural heritage sites. However, they cooperate in developing sustainable management and a scientific approach to research, as well as finding practical solutions aimed at securing stable preservation conditions for anthropogenic sediments that are vulnerable and sensitive to environmental changes, both chemical and mechanical. In this paper we present results from environmental investigations conducted in 2007 and 2012 at a location in the central part of medieval Trondheim where an in situ preservation project has been established on the site of new construction work. The project is cross-interdisciplinary, combining archaeological retrieval methods with the sampling and analysis of soil chemical parameters and the monitoring of present basic parameters such as temperature, moisture and redox potential. The monitoring has been ongoing since the beginning of 2013 and will continue until 2017.     

城郊开发区建设对东道区域地方性消解的影响研究——以长沙经济技术开发区为例

我国的城郊开发区普遍缺乏地方特色,在招商引资中易陷入低水平恶性竞争的困境,急需通过增强地方性来促进开发区的持续健康发展。基于空间生产的相关理论和对长沙经济技术开发区的实地调研,本文初步探讨了城郊开发区建设对东道区域地方性消解的机理。研究表明,城郊开发区建设主要是资本主导下的空间生产过程,主要生产可复制、可交换的同质空间,因而会消解东道区域的地方性,这在调研中突出表现为当地居民对新的空间缺乏深厚的认同和依恋。为此,有必要尊重当地人的发展需求,更好保护东道区域独特的自然环境和地方文化,从而把开发区塑造成具有地方特色的"宜业宜居"空间,以增强开发区的特色竞争力和持续发展能力。