Marginalisation and demographic change in the semi-arid Karoo, South Africa

Semi-arid areas are often considered to be environmentally and economically marginal, a situation which has been exacerbated by economic change, shifts in agricultural production and land use, and changing state policy. These themes are explored with reference to a semi-arid landscape, namely the Karoo, which covers some 40% of the geographic space of South Africa and is used primarily for extensive livestock farming. Despite long-term decline in agricultural output, the traditional mainstay of the region, and weakening small town economies, the Karoo's population and the economies of its largest service centres are growing. There are, real socio-economic needs and development backlogs, and the situation has been exacerbated by recent political marginalisation. In this study, the small towns of the region are focal points of investigation and provide a lens to investigate the changing demographic and economic dynamics of the Karoo. Most of the region's population lives in these centres which are service, collection, and distribution points for what traditionally has been an agriculture-based regional economy. This paper explores the concept of marginalisation with specific reference to historical, economic, and demographic change.     

河北邢台地震区外的小震丛集活动

1966年3月8日和22日河北省南部邢台地区发生TM6．8和M7．2大地震，之后，与其相邻的一些地区及由邢台地震引起的各烈度异常区也相继发生了小震活动。追述了邢台地震区附近的一些小震丛集活动序列，并对其活动特征进行了总结。     

岩石模量与应变振幅关系的实验研究及理论解释

地球介质的非线性弹性造成了岩石动态和静态弹性模量在数值上的差异。本文用超声波速度测量得到岩石的动模量，用含有小循环的加卸载实验得到小循环模量，用大循环的应力、应变曲线斜率得到静模量，用测点的应力、应变之比得到杨氏模量。通过改变小循环的应变振幅来研究模量与应变振幅的关系，进而比较用不同测量方法得到的模量值的差异。结果表明，动模量值最大，小循环模量值次之，大循环静模量值再次之，而杨氏模量最小。岩石非线性模量既是所受应变水平的函数，也是应变振幅的函数，模量随应变振幅的增加以指数形式下降，随应变水平增加以指数形式上升。最后简要介绍了P-M模型的基本概念，用岩石中微裂缝具有不同的分布密度，不同的打开和关闭压力来解释模量与应变振幅的关系。     

Evaluation of seismic site factors in the Mississippi Embayment. I. Estimation of dynamic properties

Deep deposits of the Mississippi Embayment, overlying the New Madrid Seismic Zone, present unique challenges for the estimation of local site effects on propagated ground motion. Limited information is available on the dynamic properties of these deposits. This paper develops generalized depth dependent modulus degradation and damping curves specific to the embayment deposits. Depth dependent small strain damping is estimated using weak motion recordings during the Enola earthquake, 2001. Modulus degradation and damping curves are further constrained using limited laboratory test data of embayment soils at low confining pressure. At high confining pressures embayment specific data is unavailable and test data from outside the embayment is used in developing the dynamic properties. The representative modulus degradation and damping curves are used in non-linear and equivalent linear one-dimensional site response analyses. A companion paper describes a large-scale probabilistic seismic hazard analysis study in the Mississippi Embayment that integrates non-linear site effects.     

Sustainability of tropical small-scale fisheries: Integrated assessment in French Guiana

Like many tropical small-scale fisheries, the French Guiana coastal fishery is characterized by the high fish biodiversity of its ecosystem, the weak selectivity of the fleets exploiting the resources, and the heterogeneity of the vessels in terms of size and fishing techniques. The Rapfish method is used to assess sustainability within 11 fishery systems by means of 27 attributes relating to ecological, economic, social, and technological fields. Overall results indicate an average performance in the weak sustainability range. Comparisons made among the FSs show a gradient of sustainability performance from the western portion of the coast to the eastern portion. Several recommendations are formulated to raise the current “sustainability” status, such as the reduction of discards. This study is used as a complementary tool to the bioeconomic model in order to define a sustainable management plan for the French Guiana coastal fishery.     

Patterns and causes of uncertainty in the American Community Survey

In 2010 the American Community Survey (ACS) replaced the long form of the United States decennial census. The ACS is now the principal source of high-resolution geographic information about the U.S. population. The margins of error on ACS census tract-level data are on average 75 percent larger than those of the corresponding 2000 long-form estimate. The practical implications of this increase is that data are sometimes so imprecise that they are difficult to use. This paper explains why the ACS tract and block group estimates have large margins of error. Statistical concepts are explained in plain English. ACS margins of error are attributed to specific methodological decisions made by the Census Bureau. These decisions are best seen as compromises that attempt to balance financial constraints against concerns about data quality, timeliness, and geographic precision. In addition, demographic and geographic patterns in ACS data quality are identified. These patterns are associated with demographic composition of census tracts. Understanding the fundamental causes of uncertainty in the survey suggests a number of geographic strategies for improving the usability and quality ACS.     

日光温室中加扣小拱棚的温湿度效应

利用2013年1-2月河北省清河县日光温室中加扣小拱棚后温湿度观测资料和气象站观测资料,采用数理统计法,对不同天气条件下小拱棚温湿度变化特征和温湿度效应进行分析。结果表明：在晴天、少云-多云天气条件下小拱棚内日最高气温分别达30.0 ℃和25.0 ℃以上,且分别比小拱棚外高1.3-6.6 ℃和1.0-4.5 ℃;在晴天、少云-多云天气条件下小拱棚内日最低气温分别为4.0-11.0 ℃和6.0-14.0 ℃,比小拱棚外高0.0-1.5 ℃。小拱棚内日最小空气相对湿度为50%左右,比小拱棚外高2%-11%,日最大空气相对湿度与小拱棚外持平或略高;小拱棚内0.0 m气温和空气相对湿度日变化幅度均小于小拱棚内0.5 m。连续寡照天气时,小拱棚内气温为5.0-15.0 ℃,空气相对湿度全天为85%以上,温度、湿度变化幅度小且与小拱棚外接近或略高。总体来讲,日光温室加扣小拱棚在晴天或少云-多云天气时具有较好的增温保湿效果,但在寡照天气时增温效果不明显。温室中小拱棚内和小拱棚外温度差、湿度差在白天尤其中午前后较大,而在夜间内外相差较小或无差异。在管理上,应注意预防晴天中午前后小拱棚内温度过高引起的灼伤和寡照天气时低温高湿引起的冻害和病害。     

东北地区中强震前的小震频度新方法探讨

1970年以来东北地区共发生13次5.0级以上地震,其中8次在时间和空间上相对独立。通过系统研究这8次中强地震前及其邻区小震活动的增强现象,发现这些中强地震前存在比较明显的小震增强现象。虽然小震增强现象在多数中强地震前存在,但是这种周期性的小震活动强弱交替轮回过程,是普遍存在的,因此,利用小震活动的增强对未来中强地震的预测比较困难。文中结合东北地区小震活动的特点,尝试提出根据小震活动空间格局是否改变统计小震频度的方法,进行了初步的应用。结果表明：利用新方法统计小震的频度更能突出中强地震前的小震频度异常,能够有效的提取东北地区中强地震前的中短期异常指标。     

非对称信息扩散理论模型及其小样本灾害事件影响评估

针对地震灾害（特别是强震事件）评估中观测样本少,信息获取难的问题以及常规信息扩散模型难以有效刻画样本数据非对称结构的不足,提出一种＂椭圆式＂非对称的信息扩散评估模型。该方法可从有限数据样本结构中客观拟合出数据信息的扩散函数,进而实现对有限数据样本信息的合理拓展。实验结果表明,该非对称信息扩散技术可对不完备数据样本进行合理逼近和有效信息扩展,评估模型计算结果与客观实际情况相符。     

Variability in the small crater population on Callisto

Previous analyses of Galileo images showed the small (≈1 km and smaller) crater population on Callisto to be lower than had been expected (Moore, J.M. et al. [1999]. Icarus 140, 294-312; Bierhaus E.B. et al. [2000]. Lunar Planet. Sci. 31. Abstract #1996). In this paper we examine the small crater population using high-resolution imagery from Callisto flybys during Galileo orbits C3, C10, C21, and C30, including several C30 regions not previously analyzed. Our findings confirm that most small craters are depleted relative to a presumed equilibrium of R = 0.22, and we find that there is significant variability in the small crater counts. While some of the variability in the small crater population on Callisto can be attributed to secondary cratering, some variability also may be explained by resetting of portions of Callisto’s surface by larger impactors. This is expected where the differential size frequency distribution of the crater production population b < 3 (where b represents the exponent of a differential power-law crater-size distribution), such that large impacts affect a greater planetary surface area than smaller craters.