World trade as the adjustment mechanism of agriculture to climate change

This paper evaluates the role of trade as a mechanism of economic adjustment to the impacts of climate change on agriculture. The study uses a model of the world economy able to reflect changes in comparative advantage; the model is used to test the hypotheses that trade can assure that, first, satisfying global agricultural demand will not be jeopardized, and, second, general access to food will not decrease. The hypotheses are tested for three alternative scenarios of climate change; under each scenario, regions adjust to the climatic assumptions by changing the land areas devoted to agriculture and the mix of agricultural goods produced, two of the major mechanisms of agricultural adaptation. We find that trade makes it possible to satisfy the world demand for agricultural goods under the changed physical conditions. However, access to food decreases in some regions of the world. Other patterns also emerge that indicate areas of concern in relying on trade as a mechanism for the adjustment of agriculture to likely future changes in climate.     

南天山榆树沟高压麻粒岩地体锆石U—Pb定年及其地质意义

南天山榆树沟高压麻粒岩地体的主体为一套蛇绿岩。从该地体顶部单元的岩石中分离出的锆石绝大部分为浑圆形或椭球形,少量为两端略圆化的四方柱状晶体;镜下粒度分析结果显示分选良好的典型沉积特征;其ＺｒＯ２／ＨｆＯ２比值在４５－５７之间;结合岩石的岩石学和地球化学特征,推测斜长石榴苏辉岩的原岩可能主要由来自洋岛的基性火山激浪沉积碎屑和洋底风化产生的粘土组成。     

Changes in Fire and Climate in the Eastern Iberian Peninsula (Mediterranean Basin)

Fire is a dominant ecological factor in Mediterranean ecosystems, and changes in the fire regime can have important consequences for the stability of our landscapes. In this framework I asked firstly, what is the trend in fire number and area burned in the eastern Iberian Peninsula, and then, to what extent is the inter-annual variability of fires determined by climatic factors. To answer these questions I analysed the meteorological data (temperature and precipitation) from 350 stations covering the eastern Iberian Peninsula (1950–2000), and the fire records for the same area (historical data, 1874–1968, and data from recent decades, 1968–2000). The results suggested a slight tendency towards decreasing summer rainfall and a clear pattern of increasing annual and summer temperatures (on average, annual temperatures increased 0.35 °C per decade from 1950 to 2000). The analysis of fire records suggested a clear increase in the annual number of fires and area burned during the last century; however, in the last three decades the number of fires also increased but the area burned did not show a clear trend. For this period the inter-annual variability in area burned was significantly related to the summer rainfall, that is, in wet summers the area burned was lower that in dry summers. Furthermore, summer rainfall was significantly cross-correlated with summer area burned for a time-lag of 2 years, suggesting that high rainfall may increase fuel loads that burn 2 years later.     

Variogram-Based Descriptors for Comparison and Classification of Rock Texture Images

Mathematical Geosciences - Rock characterization is typically performed by geologists in mining companies and involves the analysis of several meters of drill-hole samples to describe distinctive...     

空气反循环钻探在紫金山金铜矿生产勘探中的应用

金山金铜矿经过几十年的大规模生产,金矿开采已进入矿体的边部和底部,矿体规模小,形态、产状复杂,矿石性质变化大,保有资源储量仅能满足矿山未来几年的生产需要,急需勘探接替资源。结合矿山生产实际和矿区地质条件,选择空气反循环钻探作为主要探矿手段。在分析空气反循环钻探工艺原理和适用条件的基础上,对施工机具的选取进行了详细阐述。通过对比,分析空气反循环钻探在紫金山金铜矿露采生产勘探、北口排土场含金废石（人工堆渣“矿床”）勘查中的成效以及问题。实践证明,空气反循环钻探技术可以用于紫金山金铜矿的生产勘探。