Limb bones asymmetry and stress in medieval and recent populations of Central Europe

Monitoring the degree of asymmetry in different parts of the human body can contribute to population studies, as it may be connected indirectly with the social structure, living conditions, and also with biomechanical stress affecting the person. Analysis of asymmetry may also assess preferential use of the right or left of the body during specific activities. This study is based on the measurements of bones of the upper and lower limbs of skeletons derived from the remarkable medieval cemeteries of Mikulčice‐Kostelisko (78 male, 132 female) and Prušánky (66 male, 69 female) (9th–12th centuries AD), and a series of skeletons representing a recent population from Bohemia (143 male, 157 female). The objective was to assess directional asymmetry (DA), fluctuating asymmetry (FA) and antisymmetry (AS) of the dimensions of the evaluated bones, and to use these data to compare the characteristics of the medieval and recent populations. DA was recorded in most dimensions. In the upper limb, the humerus exhibited the greatest expression of asymmetry, and, with the exception of the clavicle, DA was always more pronounced on the right side. Conversely, DA was less prevalent in the lower limb bones. It was more pronounced on the transverse, sagittal and circumferential dimensions of the diaphyses and epiphyses than on the length, and in most cases it was on the left side. The FA values were very low, and almost negligible in relation to the size. Nevertheless, FA was markedly more frequent on the lower than on the upper limb. In contrast to the medieval population, the recent population had higher FA and DA values. Thus, we propose that people from this medieval population were subjected to lower developmental stress than the recent sample. Copyright © 2008 John Wiley & Sons, Ltd.     

Fluid flow and stability of the US continental slope offshore New Jersey from the Pleistocene to the present

We predict that portions of the New Jersey continental slope were unstable approximately 0.5 million years ago. This instability was caused by rapid sediment loading during a Pleistocene sea‐level lowstand and by flow focusing in underlying, permeable Miocene strata. The simulated instability is consistent with soft‐sediment deformation and small slumps in Pleistocene strata of the Hudson Apron. Stability of the New Jersey margin has increased since 0.3 Ma because sedimentation rate has decreased. Today, the modelled factor of safety (FS) for the upper slope is approximately 1.5 whereas in the lower slope it exceeds 3. We predict that sedimentation rate is a dominant factor on slope stability. When rapid and asymmetric loading of a highly permeable sedimentary layer occurs, the location of instability can shift seaward to regions where sedimentation rates are low. Stability calculations use pressures and effective stresses predicted by a coupled sedimentation‐fluid flow model. This hydrodynamic analysis demonstrates how the interplay of sedimentation and fluid migration affects the distribution, timing, and size of sedimentary failures.     

Stability of Slender Masonry Columns with Circular Cross-Section under Their Own Weight and Eccentric Vertical Load

This work concerns the stability of unreinforced masonry slender circular cross-sectional columns subjected to their own weight and eccentric vertical load. Cantilever columns are examined, considering that the material has infinitely linear elastic behavior in compression and has no tensile strength. For the analysis, an existing numerical model and solution procedure developed for the stability analysis of masonry elements with rectangular cross-section are utilized and adapted to the circular columns. For the instability of the columns, an appropriate criterion that relates the top lateral deflection to the intensity of the applied eccentric vertical load is employed. By considering a reference column, critical buckling load is obtained, behavior of the column interpreted and efficiency of the numerical model emphasized. Performing a nonlinear buckling analysis using a general purpose software on this reference column, obtained results are compared with those of the adapted procedure of the present study. Implementing parametric analyses on reference column, effects of the column slenderness, eccentricity of vertical load, elastic modulus, and self-weight on the buckling load are investigated. Presented calculation procedure provides a useful tool in order to calculate the critical loads or to check the stability of masonry circular columns.     

一种古籍修复用纸伸缩性检测方法的探讨

补纸选配是古籍修复中的重要环节,但其伸缩性尚未引起足够重视。古籍修复补纸均为传统手工抄制,浸水后强度较低。按现行国家标准浸湿法检测补纸伸缩性时易产生撕裂、变形等问题,适用性较差。本研究探讨了一种古籍修复补纸的伸缩性检测方法——喷润法。利用水分检测仪对补纸相对含水量进行测定,从测量时间和可操作性的角度验证了该方法的可行性。通过十余种常用补纸的伸缩性检测结果发现,喷润法与浸湿法所得结果具有较好的一致性。随后探讨了古籍书叶伸缩性检测的适用性,并结合具体案例,建议在修复前分析古籍书叶与补纸的伸缩性匹配度。喷润法有效避免了补纸浸湿后的拉伸变形或破裂,既适用于古籍修复补纸,也适用于古籍书叶的无损检测,可为古籍修复策略的制定提供科学依据和参考。     

书画装裱材料——宣纸形稳定性的研究

为了加强纸质物的保护,对书画装裱材料宣纸的湿形稳性变化规律进行了研究。通过对不同条件下干燥方法对宣纸形变影响的研究,对纸张变形的原因进行了探讨。实验结果表明,宣纸具有随湿度变形的特性,变形程度与纸的纤维组成和干燥方法有关。采用梯度干燥的方式纸张的尺寸稳定性没有明显的改善。厚度和收缩率相关分析说明二不存在相关性。随着纸张干湿交替处理次数的增多,其变形性趋于减小。为提高纸张的形稳性,可预先进行处理。     

近二十年来中国社会稳定研究述评

社会稳定问题是事关改革开放和现代化建设的关键问题。在相当长的一段时间里,理论界关于社会稳定的研究囿于意识形态和政治因素,局限在狭小的范围,甚至有些领域被视为研究的禁区。随着改革的日益纵深,各种社会矛盾凸显,诸如农民因税费负担引发的抗争、工人因下岗失业引发的抗争、业主因权利受损引发的抗争等问题都亟需理论上的解释和说明。为此,研究者们从不同角度、不同层面对社会稳定问题进行了理论探讨,取得了不少有价值的成果。     

青海藏族聚居区实现长治久安的思考及对策

在现代社会,民族问题是影响国家和社会长期稳定的重要因素之一。本文对青海藏族聚居区的长治久安问题进行了客观分析并针对政府决策和执行提出了对策建议。     

Managment of Beached Shipwreck Archaeological Sites: Defining Stability

The archaeological remains of ships in the beach zone are part of a complex and dynamic system. Being periodically exposed and reburied, they vary between being both visible and frequently forgotten features of the physical and cultural coastal landscape. These limited and non-renewable resources are highly susceptible to instability within the landscape. Challenges to stability result in these resources being damaged, ignored, or forgotten, leading to a potential loss of pertinent social, economic, and physical information. Although little can be done to prevent certain physical actions, a better understanding of physical and cultural processes allows for their mitigation and better management practices for the beached shipwreck resource. This paper looks at how stability is defined in relation to beached shipwreck sites and how these definitions impact the management of the resource of two case study sites in Maine and North Carolina.     

中东过度城市化与社会稳定

城市化是世界各国经济社会发展的必由之路,但二战后中东国家的城市化发展模式与西方发达国家城市化发展的历史经验大不相同,实行的是以西方城市化为参照目标的赶超战略,导致严重的过度城市化现象。中东过度城市化的畸形发展引发一系列城市化问题,并对中东地区的社会稳定构成重要影响,体现在过度城市化孕育着不稳定的社会心理;过度城市化危及社会秩序稳定;过度城市化对城市社会结构产生影响,扩大底层社会的基础。     

构建和谐社会需要良好的社会心理

构建社会主义和谐社会除了健全各种机制、切实把维护公众的合法权益作为处理社会矛盾、促进社会安定和谐的出发点和落脚点之外,还要密切关注人们的社会心理。因为,良好的社会心理是经济社会转型的重要变量,对社会发展有巨大的能动作用,是社会稳定和社会秩序规范的重要条件。