Decay of softwood in archaeological wooden artifacts

Hardwoods and softwoods were used side by side throughout Egyptian history, and importing softwoods that had an attractive color and texture was common. Over the decades, artifacts based on hardwoods and softwoods underwent deterioration phenomena, sometimes reaching either a level of brittleness or turning into a wood powder that may easily crumble. These levels of decay/degradation are often difficult to handle in terms of conservation treatments. To study or identify the reasons for decay has always been a point of interest for conservation purposes, but to assess decay and choose an appropriate treatment according to the state of preservation for the sake of keeping an artifact intact has become a subject of major importance. It is difficult at times to understand the deterioration process, because hardwoods and softwoods are different in structure, properties, and chemical composition. For this preliminary study, decayed samples from three commonly used softwood types, cypress (Cupressus sp.), cedar (Cedrus sp.), and pine (Pinus sp.), were identified and chosen. Scanning electron microscopy (SEM) of the samples indicated the degree of decay. Decayed and non-aged samples of the same wood type were analyzed using Fourier transform infrared spectroscopy (FTIR), and all the major carbohydrate and lignin bands were recorded. The strong hydrogen bonded (O–H) stretching absorption associated with water linked by hydrogen bonds to the –OH groups of cellulose and hemicelluloses in all decayed samples increased with decay. The brown powdery, fragile samples that had been evidently affected by microbial decay had a higher amount of lignin. The lignin/carbohydrate ratio was calculated and results compared. The increase of either lignin percentage or extractives in some of the samples had caused a darkening of color in both cypress and cedar samples, but the pine sample did not have the same texture and appearance. In cases where the lignin percentage decreased the samples had changed to a slightly lighter color. FTIR results explained the decay phenomena observed in SEM micrographs and helped assess wood decay and also confirmed results that had been previously obtained while applying traditional chemical analysis on wood.     

远程开放教育教与学的实践与思考--对2001春开放教育教学检查的反思

对远程开放教育教与学模式的探讨,有助于及时发现开放教育试点中存在的问题,纠正工作中的偏差和失误,以便使试点工作健康顺利运行.     

Religiosity,the headscarf,and education in Turkey: an analysis of 1988 data and current implications

Previous research highlights the continuing relevance of family culture in explaining educational inequalities in Turkey, especially patriarchal beliefs and practices that discourage investment in the education of girls. We extend that research by introducing two much‐debated, but empirically untested, aspects of family culture – parental religiosity and headscarf preferences. An analysis of a nationally representative sample of 15–19 year olds in 1988 shows that while religiosity had no significant effect on educational attainment, children who lived in families whose fathers expected them to wear a headscarf in public had lower educational attainment, especially girls. The large negative headscarf effect suggests that the government ban on headscarves in schools may be an obstacle to eliminating gender inequality in education. The results are discussed in light of recent trends in Turkish society.     

试论明代前期中国与东南亚的丝绸贸易

中国与东南亚的丝绸贸易源远流长 ,明前期 ,在“海禁”政策和统治者“薄来厚往”思想的影响下 ,朝贡贸易成为两地丝贸的主流形式。私人贸易虽有所发展 ,但其重要性却远不如前代。随着两地贸易的发展 ,中国丝绸在东南亚的行销范围进一步扩大 ,并一直保持着出口优势     

Fish Oil Supplementation in Pregnancy and Neurodevelopment in Childhood—A Randomized Clinical Trial

A double-blind randomized controlled trial of n-3 long-chain polyunsaturated fatty acid (n-3 LCPUFA) supplementation or matching placebo during third trimester of pregnancy was conducted within the COPSAC₂₀₁₀ mother-child cohort consisting of 736 women and their children. The objective was to determine if maternal n-3 LCPUFA pregnancy supplementation affects offspring neurodevelopment until 6 years. Neurodevelopment was evaluated in 654 children assessing age of motor milestone achievement, language development, cognitive development, general neurodevelopment, and emotional and behavioral problems. Maternal n-3 LCPUFA supplementation during pregnancy improved early language development and reduced the impact of emotional and behavioral problems. The n-3 LCPUFA supplementation was in boys associated with the earlier achievement of gross motor milestones, improved cognitive development, and a reduced impact of emotional and behavioral problems.     

福建省南平市科技特派员制度的实践与思考

南平市实施的科技特派员制度,是福建省农村工作的一项制度创新,在近年来的社会主义新农村建设中发挥了重要作用。本文主要通过对南平市科技特派员制度的调研,考察其实践发展和成效,分析存在的问题和困难,提出了促进科技特派员制度发展的建议与对策。     

高师体育课程的整体改革与建设

伴随着新世纪的到来 ,高师体育课程建设必须突破固有的旧观念 ,摒弃传统的以运动技术教学为主的旧的课程体系 ,建立以发展学生身心健康为中心的新的课程体系 .同时 ,运用系统分析的方法将师资培训、课程设计、大纲和教材、体育方法及体育考核等五项基本要素进行整体改革     

对机械设计基础课教学难点的探讨

依据多年的教学经验,简明扼要地提出了机械设计基础课教学的难点在于知识的抽象和错综复杂,与此相适应,应采取不同的教学方法.