Multiple Residence and Cyclical Migration: A Life Course Perspective*

As a result of restrictive time-space bounds in viewing migration, surprisingly little is known about the tempos and rhythms of geographical mobility in America. We discuss limitations of the conventional definition of migration and develop a life course framework of multiple residence and cyclical migration. Results of an Arizona-based case study reveal that multiple residence is common and more diverse than the annual influx of elderly snowbirds. Coming to grips with multiple residence and recurrent mobility in the United States represents a fundamental challenge in population and migration studies.     

Application of the telluric and magnetotelluric methods in selection of sites for nuclear plants

The paper deals with the application of the telluric method and of magnetotelluric soundings including experimental and model data on the localization of tectonic disturbances in connection with the selection of appropriate sites for nuclear plants.     

辽南核电站厂址区断层的评价问题

作者通过对核安全法规的学习和前人对辽南核电站厂址区断层的调查，并结合对断层实际踏勘，认为厂址区附近的东岗断层属于现行法规（ＨＡＦ０１０１）中规定的能动断层。但是，仅此一点并不能构成对推荐厂址的威胁，因为断层距厂址直线距离约４ｋｍ，断层的地表或近地表错动不会直接影响到核反应堆的安全。     

电阻率-孔隙度、电阻率-含油（气）饱和度关系的一般形式及其最佳逼近函数类型的确定（Ⅰ）

本文导出了电阻率-孔隙度、电阻率-含油（气）饱和度关系的一般形式--两个对称的表达式,并给予了实验证明。同时,本文指出,Archie公式、Winsauer公式和双水公式都是一般形式在一定条件下的特例。在一般情况下,本文给出了14个能够逼近这两个表达式的函数类型,通过岩芯数据进行选优,可以得到适合不同地区或地层的最优方程。根据本文理论建立的解释方法和研制的软件已经在油田生产中推广应用并取得了良好效果。 由于涉及内容较多,全文分两部分撰写。以下是本文的第（Ⅰ）部分,即一般形式的导出及实验验证;而最佳函数类型的确定及其在生产中的应用将作为本文的第（Ⅱ）部分发表。     

中国西北C-3植物的碳同位素组成与年降雨量关系初探

 本文对不同年降雨量环境下生长的藜、独行菜、魁蓟和平车前这4种常见C-3植物的δ¹³C进行了分析,发现这4种C-3植物的δ¹³C组成都表现出随年降雨量减少而变重的趋势,其中藜和独行菜的碳同位素组成对降水变化的响应相对要较其它2种植物强烈得多。藜、独行菜和魁蓟的δ¹³C组成与年降雨量有显著的线性关系,平车前碳同位素组成与年降雨量没有显著的相关性,表明藜、独行菜和魁蓟的δ¹³C组成可作为年降雨量的替代性指标,平车前的δ¹³C组成不能作为年降水的替代性指标。     

不同型式暗支撑短肢剪力墙抗震性能试验研究

本文选取短肢剪力墙结构体系中较为薄弱的抗震构件“一”形短肢剪力墙，采用不同的暗支撑型式进行了两个1／2缩尺的带暗支撑短肢剪力墙构件的低周反复荷载试验，比较分析了它们的承载力、刚度、延性、滞回特性、耗能能力及破坏机制，建立了其承载力计算模型与方法。计算结果与实测值符合较好。     

Comparison of traditional wild plant knowledge between aboriginal communities inhabiting arid and forest environments in Patagonia, Argentina

The Mapuche people have a deeply rooted tradition of wild plant use for their subsistence. In this study we evaluated whether plant selection by the Mapuche is influenced by environmental constraints. Selection patterns of wild plant richness were compared in two Mapuche communities sharing the same traditions and beliefs but inhabiting different environments. Similarities and differences in the use patterns of wild medicinal and edible plants were quantitatively analyzed by using concepts derived from ecological theory. The Cayulef community is settled in the NW Patagonian (herbaceous) steppe while the Curruhuinca community is established near the Andean temperate forest, 100 km away from each other. Free-listing and semi-structured interviews were conducted with 32 families in Cayulef and 39 in Curruhuinca corresponding to 80% and 40% of each population, respectively. Data were analyzed by means of the Jaccard similarity index and statistical tests. The main results of this study showed that the home environment is a determinant factor that influences which plant species are utilized, as is the anthropic environment (with its high exotic species richness) in each community. However, similar patterns were found with respect to plant families, ways of utilization, plant parts and life forms utilized irrespective of where the communities are settled. In addition, in both populations, wild plant richness was significantly higher for medicinal than for edible species. Our results showed that the use of wild plants is primarily based on the utilization of species belonging to the nearest ecological environments that have both therapeutic and dietary functions.     

Soil erosion along a long slope in the gentle hilly areas of black soil region in Northeast China

Characteristics of soil erosion change along a long slope in the gentle hilly areas in black soil region in Northeast China are discussed. A simplified slope model based on seg-ments was used to analyze the runoff data and soil erosion data observed between 2003 and 2004 over 10 field plots with different slope length in Heshan Farm, Heilongjiang Province. We found that soil erosion rate over long slopes in the black soil region changed alternatively along the slope and creates alternative zones of intensive erosion and week erosion.The exact place of each zone is different for different rainfall conditions. In a year with less and mild precipitation, rill cannot happen within the top 50 m, while in a year with large and inten-sive precipitation, rill can be formed starting even at 15 m from the top of the slope.     

Use of high spectral resolution remote sensing to determine leaf palatability of eucalypt trees for folivorous marsupials

In this study we assess the feasibility of remotely measuring canopy biochemistry, and thus the potential for conducting large-scale mapping of habitat quality. A number of studies have found nutrient composition of eucalypt foliage to be a major determinant of the distribution of folivorous marsupials. More recently it has been demonstrated that a specific group of secondary plant chemicals, the diformylphloroglucinols (DFPs), are the most important feeding deterrents, and are thus vital determinants of habitat quality. We report on the use of laboratory spectroscopy to attempt to identify one such DFP, sideroxylonal-A, in the foliage of Eucalyptus melliodora, one of the few eucalypt species browsed by folivorous marsupials. Reflectance spectra were obtained for freeze-dried, ground leaves using near infrared spectroscopy (NIRS) and for both oven-dried and fresh whole leaves using a laboratory-based (FieldSpec) spectroradiometer. Modified partial least squares (MPLS) regression was used to develop calibration equations for sideroxylonal-A concentration based on the reflectance spectra transformed as both the first and second difference of absorbance (Log 1/R). The predictive ability of the calibration equations was assessed using the standard error of calibration statistic (SECV). Coefficients of determination (r²) were highest for the ground leaf spectra (0.98), followed by the fresh leaf and dry leaf spectra (0.94 and 0.87, respectively). When applied to independent validation sub-sets, sideroxylonal-A was most accurately predicted from the ground leaf spectra (r² = 0.94), followed by the dry leaf and fresh leaf spectra (0.72 and 0.53, respectively). Two spectral regions, centred on 674 nm and 1394 nm, were found to be highly correlated with sideroxylonal-A concentration for each of the three spectral data sets studied. Results from this study suggest that calibration equations derived from modified partial least squares regression may be used to predict sideroxylonal-A concentration, and hence leaf palatability, of Eucalyptus melliodora trees, thereby indicating that the remote estimation of habitat quality of eucalypt forests for marsupial folivores is feasible.     

模糊数学在混凝土构件耐久性评定中的应用初探

根据钢筋混凝土构件耐久性评估的特点，借助模糊数学的理论，将结构构件的损伤程度作为构件这一论域U上的模糊子集A，利用所构造的多元隶属函数，对构件的损伤程度进行评价，提出了一种耐久性分极评定方法，这一方法克服了以往在结构构件评价中存在的主观、经验等因素，该法的特点是使耐久性的每一级别都有确切的剩余寿命的内涵，而多元隶属函数法的引入减小了主观因素对评定结果的影响。经实例验算，该法准确率可达90%。