论长江中游地区新石器时代晚期的生计经济与人口压力

长江中游地区新石器时代晚期的主要生计方式是稻作农业,因渔猎所占比重不同而又可细分为山地型与平原型。水田稻作农业具有集约化程度高,产出也较高的特点。稻田耕作系统的形成与维护需要大量劳力,从而刺激人口迅速增长,结果造成人口压力。自然环境的数次波动更加剧了这种压力。因人口压力而引发的移民、战争和社会重组等,成为推动初期社会复杂化进程的主要原因。     

Carbon dioxide controlled earthquake distribution pattern in the NW Bohemian swarm earthquake region,western Eger Rift,Czech Republic – gas migration in the crystalline basement

The ascent of magmatic carbon dioxide in the western Eger (Oh?e) Rift is interlinked with the fault systems of the Variscian basement. In the Cheb Basin, the minimum CO₂ flux is about 160 m³ h^?1, with a diminishing trend towards the north and ceasing in the main epicentral area of the Northwest Bohemian swarm earthquakes. The ascending CO₂ forms Ca‐Mg‐HCO₃ type waters by leaching of cations from the fault planes and creates clay minerals, such as kaolinite, as alteration products on affected fault planes. These mineral reactions result in fault weakness and in hydraulically interconnected fault network. This leads to a decrease in the friction coefficient of the Coulomb failure stress (CFS) and to fault creep as stress build‐up cannot occur in the weak segments. At the transition zone in the north of the Cheb Basin, between areas of weak, fluid conductive faults and areas of locked faults with frictional strength, fluid pressure can increase resulting in stress build‐up. This can trigger strike‐slip swarm earthquakes. Fault creep or movements in weak segments may support a stress build‐up in the transition area by transmitting fluid pressure pulses. Additionally to fluid‐driven triggering models, it is important to consider that fluids ascending along faults are CO₂‐supersaturated thus intensifying the effect of fluid flow. The enforced flow of CO₂‐supersaturated fluids in the transitional zone from high to low permeability segments through narrowings triggers gas exsolution and may generate pressure fluctuations. Phase separation starts according to the phase behaviour of CO₂‐H₂O systems in the seismically active depths of NW Bohemia and may explain the vertical distribution of the seismicity. Changes in the size of the fluid transport channels in the fault systems caused, or superimposed, by fault movements, can produce fluid pressure increases or pulses, which are the precondition for triggering fluid‐induced swarm earthquakes.     

Modelling of hydrology and potential population levels at Bronze Age Jawa,Northern Jordan: a Monte Carlo approach to cope with uncertainty

An annual water balance model for Wadi Rajil, in Northern Jordan, is used to simulate the ancient water supply system for the Early Bronze Age site of Jawa. The model includes: water delivery from the catchment; local pond storage; and water demand for people, animals and irrigation. A Monte Carlo approach is used to incorporate the uncertainty associated with a range of factors including rainfall, evaporation, water losses and use. The stochastic simulation provides estimates of potential population levels sustainable by the water supply system. Historical precipitation estimates from a Global Circulation Model, with uncertainty bounds, are used to reconstruct the climate at Jawa in the Early Bronze Age (EBA). Model results indicate that the population levels in the predicted wetter conditions during parts of the EBA could have risen to ∼6000 and may have been higher in wet years. However, palaeoclimatic proxies also suggest prolonged droughts in the EBA; and during these periods the water management system was unable to provide adequate supply for a population of 6000. The utility of Monte Carlo based hydrological modelling as a tool within archaeological science is discussed.     

Resource abundance constraints on the early post-contact Cherokee population

We present the combination of an analysis of resource demand by the early post-contact (1721) Cherokee population with spatially explicit estimates of production for five key resources: architectural land, agricultural land, firewood, hard mast, and white-tailed deer (Odocoileus virginianus). We combine a recent synthesis of village location and population, a map of recognized Cherokee territory, digital terrain data, estimates of per capita demand, and productive capacity for each resource. Average, high, and low demands were estimated for each resource and assigned based on a weighted function of terrain and distance from each village. We conclude that Cherokee demands for architectural and agricultural land, hard mast, and fuelwood were easily met within a short proximity to each town under all combinations of production and demand. These resources were likely not limiting, and were satisfied for the entire Cherokee population by less than 1% of the entire recognized Cherokee territory in 1721. These resources likely exceeded demand even when sources were restricted to the convex hull of the Cherokee territory, or to near stream, flat regions. Deer resources were likely harvested over a much larger area and to a much greater extent. Our best estimate of deer resource demand was 32% of annual sustainable production in the Cherokee territory, with from 16 to 48% of estimated sustainable production harvested for low and high demand estimates, respectively. Our estimates vary in response to uncertainties in deer production, harvest proportion, deer density, and sustainable harvest rates. Deer demand was substantially higher under all combinations of conditions than that available within the convex hull of Cherokee villages, indicating significant travel was needed to furnish deer requirements. Spatially explicit models that consider terrain- and distance-related tradeoffs suggest that Cherokee demand for deer drove harvest over areas consisting of over half the recognized Cherokee territory.     

Pore pressure evolution and fluid flow during visco‐elastic single‐layer buckle folding

Pore pressure and fluid flow during the deformational history of geologic structures are directly influenced by tectonic deformation events. In this contribution, 2D plane strain finite element analysis is used to study the influence of different permeability distributions on the pore pressure field and associated flow regimes during the evolution of visco‐elastic single‐layer buckle folds. The buckling‐induced fluid flow regimes indicate that flow directions and, to a lesser degree, their magnitudes vary significantly throughout the deformation and as a function of the stratigraphic permeability distribution. The modelling results suggest that the volumetric strain and the permeability distribution significantly affect the resulting flow regime at different stages of fold development. For homogeneous permeability models (k > 10^?21 m²), low strain results in a mostly pervasive fluid flow regime and is in agreement with previous studies. For larger strain conditions, fluid focusing occurs in the buckling layer towards the top of the fold hinge. For low permeabilities (<10^?21 m²), local focused flow regimes inside the buckling layer emerge throughout the deformation history. For models featuring a low‐permeability layer embedded in a high‐permeability matrix or sandwiched between high‐permeability layers, focused flow regimes inside the folded layer result throughout the deformation history, but with significant differences in the flow vectors of the surrounding layers. Fluid flow vectors induced by the fold can result in different, even reversed, directions depending on the amount of strain. In summary, fluid flow regimes during single‐layer buckling can change from pervasive to focused and fluid flow vectors can be opposite at different strain levels, that is the flow vectors change significantly through time. Thus, a complete understanding of fluid flow regimes associated with single‐layer buckle folds requires consideration of the complete deformation history of the fold.     

中国人口地理学研究的回顾与展望

中国人口地理学直至20世纪30年代前后才形成。新中国成立后,开始得以发展。自党的十一届三中全会后,因贯彻改革开放的方针,促进了人口地理学的蓬勃发展。文章最后,展望了人口地理学的发展趋势。     

加拿大人回发展与人回迁移

本文简析加拿大人口发展与人口迁移过程,以及人口迁移对加拿大人口增长、种族、语言构成、人口分布及未来人口增长的影响。     

城市体系规模结构预测方法应用研究——以内江市为例

本文利用城市体系规模分布模型对内江市城市体系分形特征及规模结构进行了分析预测,指出了内江城市体系发展规律及促进其快速发展规律及促进其快速发展的对策措施。     

The ballistics of seventeenth century musket balls

ABSTRACT

This paper investigates the firing of seventeenth Century musket balls. Prior to this research, the main concerns with making range predictions were associated with the deformed shape of the musket balls affecting their drag coefficient and therefore their distance to ground impact. However, the distance due to bounce and roll after initial impact has been unknown. In this work, the distance travelled after the first ground impact greatly exceeded expectations, with the musket balls approximately doubling the distance to their final resting positions. From these findings the initial factors thought to have had high relevance to the final resting position of the musket ball (velocity variation and drag co-efficient) become less significant and factors such as ground hardness become more prominent. The knowledge gained during this investigation will allow more accurate information to be obtained on the firing positions of opposing forces during conflicts in the English Civil War.     

Geomorphology and the sand and gravel industry of west Central Scotland

The countryside around towns is under increasing pressure for development as a result of the centrifugal forces which have characterised the capitalist urbanisation process in the post‐war era. Conflict between pro‐growth and anti‐growth interests is now endemic in many peri‐urban areas. This paper identifies the principal agents involved in the production of the built environment in the urban fringe and presents a detailed analysis of how divergent interests interact to determine the nature of the fringe environment. The research informs academic debate on rural land conversion and provides guidance for decision‐makers charged with management of the urban fringe.