A Study on Anxiety Characteristics and Its Influencing Factors in Children Left in Rural Areas

目的:了解农村留守儿童焦虑的特点并探讨其影响因素。方法:对取自重庆、贵州两地乡镇的667名中小学生(包括留守及非留守儿童)进行焦虑水平及相关因素的调查。结果:农村留守儿童在状态焦虑水平上要明显地高于父母均在家的儿童,而两者在特质焦虑上没有显著的差异。同时,农村留守儿童个体焦虑水平之间存在着一定差异。首先,父母离开时,儿童的年龄越小,留守儿童的焦虑水平越高。其次,父母与留守儿童的联系频次对其焦虑水平也有重要的影响。结论:父母在儿童的早期最好避免与其长期分离,外出打工后要尽量加强与孩子的联系,将有助于缓解留守儿童的焦虑情绪。</p

Catalytic Behaviors and Stability of Y_2O_3-Modified Ni/SiO_2 for Partial Oxidation of Methane into Synthesis Gas

采用常规浸渍法制备Y_2O_3修饰的Ni/SiO_2催化剂,并考察其催化甲烷部分氧化(POM)制合成气反应性能。结果表明,Y_2O_3的引入减小了金属Ni的粒径,有效提高了Ni在载体表面的分散性,增强了金属Ni与载体SiO_2间的相互作用,从而使催化剂的抗烧结、抗积碳能力,以及催化剂的POM反应性能得以改善。A series of Y_2O_3-modified Ni SiO_2 catalysts were synthesized by a conventional impregnation method.Catalytic performances for the partial oxidation of methane(POM) to synthesis gas were investigated.The addition of Y_2O_3 promotes a decrease in size of Ni particles supported on silica,increased the dispersion of Ni particles,and enhanced the interaction between Ni and silica.These properties gave the catalysts increased anti-sintering and resistance to carbon deposits.The catalytic behaviors of the Ni-based catalysts for POM were significantly improved when Y_2O_3 was introduced.国家自然科学基金(21373169);; 教育部创新团队项目(IRT1036)资助~

Development of the viviparous hypocotyl of mangrove and its adaptation to inter-tidal habitats:A review

作者简介: 闫中正( 1978～) , 男, 河南南阳人, 硕士生, 主要从事红树植物生理生态学研究。E-mail : nytv@ sohu. com 通讯作者Author for correspondence. E-mail: wenqing2001@ hotmail. com[中文文摘]热带亚热带海岸潮间带的高盐、淹水、土壤缺氧和潮水冲击等不良环境因子导致了红树植物在形态、生理和生态方面的特异性 ,尤其是其独特的胎生现象。从红树植物胎生繁殖体在母体的发育过程和繁殖体落地后对潮间带生境的适应两个角度探讨了红树植物胎生现象的适应意义。红树植物的胎生现象是对潮间带盐胁迫、淹水、土壤缺氧和潮水冲击等综合生境的适应 ,而不是单独其中一种胁迫因子的适应。红树植物胎生繁殖体在母体的发育过程中通过能量积累、渗透调节、形态完善等过程为掉落以后适应潮间生境做准备 ,掉落的胎生繁殖体依靠从母体获得的能量和营养克服潮间带的盐胁迫、淹水、土壤缺氧和潮水冲击等多重胁迫。红树植物胎生繁殖体落地后的能量收支平衡是决定繁殖体定居成功与否的关键 ,而胎生现象的意义正是通过胎生繁殖体在母体发育过程中积累足够的能量和营养来适应潮间带生境。红树植物胎生繁殖体落地后苗木在潮间带滩涂的生长发育过程中存在一个能量“阈限”,能阈的高低决定于潮间带生境的恶劣程度 ,而突破能阈能力决定于胎生繁殖体所携带的能量与营养的数量。这为红树林湿地恢复提供了理论基础 ,但还需要更多的证据来支持该理论.[英文文摘]Mangroves are a diverse group of predominantly tropical trees and shrubs growing in the marine intertidal zone where conditions are usually harsh , restrictive and dynamic. The peculiarities of the mangrove intertidal habitat causes the peculiarity of its structure, physiology and ecology . The vivipary of mangroves is one particular feature which is the result of long-term adaptation to the inter-tidal environment. The adaptive significa nce of vivipary to mang rove plants was reviewed from two aspects: propagule development while still attached on the mat ernal plants and adaptation to inter-tidal environments of propagules after release . Vivipary in mangrove plants is an adaptation to the integ rat ed stresses of salt, water logging and tide,but not any single stress. During t he development of vivipar ous propag ules while still attached to maternal plants, they accumulate energy , nutrients and osmotica and perfect their structure, adaptating them to t he intertidal environment after release. The viviparous propagules depend on the energy and nutrients accumulated from maternal plants to cope with salt and waterlogging stresses. The success or not of the ecesis of vivipar ous propagules depends on the balance of energy income and expenditure . The significance of vivipary in mang rove plants is to accumulate enough energy and nutrients to cope with the intertidal environment. A “t hr eshold”hypothesis is put forw ard in this paper . According to this hypothesis, there is a threshold of energy during growth and development of the viviparous propagules in the intertidal environment . The height of the threshold depends on t he degree of environmental stress, such as water salinity, w aterlogging duration and photo synthetic illuminat ion. The ability to climb above the threshold depends on storing sufficient quantity of energy and nutrients in viviparous propagules. This threshold hypothesis calls for more direct evidence .国家自然科学基金资助项目 (3 0 2 0 0 0 3 1

构建福建绿色产业集群发展的评价指标体系

加快产业集聚,培育产业集群,是福建发展新型工业化的重要举措。为实现产业集聚可持续发展,建立评价指标体系是重要的基础性工作。文章探讨了构建产业集聚评价指标体系的作用、设计思路与原则,研究了产业集聚评价指标体系的结构及其主要内容,并围绕绿色产业集群的建设,提出一些建议。福建省基础研究与软科学研究重点项目资助(项目编号:2005R043

基于IPAT模型的福建环境效率定量测评

随着人们对资源和环境问题的关注逐渐加强,如何对这些问题进行定量分析成为一个重要的课题。其中一个很重要的方面,就是在现行的发展模式下,按照经济规划的发展要求,

Diet composition of Difflugia tuberspinifera( testate amoeba) based on a clone library technique

瘤棘砂壳虫是东亚特有的原生动物,广泛分布于长江与珠江中下游以及福建地区的湖泊和水库,作为水生态系统的捕食者,在维持水生态系统的结构与功能方面发挥着重要作用。利用18S rrnA基因PCr扩增和克隆文库测序等分子生物学技术方法,从基因水平研究瘤棘砂壳虫的食物组成。结果表明:所获得的46条序列在97%相似度水平含有11类OTuS(OPErATIOnAl TAXOnOMIC unITS,操作分类单元),其中包括轮虫6个,桡足类5个,说明瘤棘砂壳虫的捕食类群以轮虫和桡足类为主,同时也证明单细胞生物可以直接以多细胞的后生动物为食。此外,通过克隆文库测序技术分析原生动物的食物组成比例,不仅是一种方便、高效、快速,重复性高的方法,同时也为分析原生动物的生态功能提供了一种新的视角。Difflugia is a morphologically diverse genus of the free-living shelled amoeboid protozoa that are important components of freshwater ecosystems and play crucial roles in nutrient cycles and energy flow through food webs.Difflugia tuberspinifera is an endemic species of East Asia and is widely distributed in freshwater lakes and reservoirs in China.Clearly,this species plays a critical role in maintaining the structure and function of freshwater ecosystems.However,little is known about its diet composition and predatory behavior at both species and gene levels.This testate amoeba( D.tuberspinifera) was first found in the Wujiang River,Guizhou Province,China.Subsequently,more detailed studies on its morphology and biometry have been done on natural populations from Yangtze River and Pearl River valleys,and Fujian reservoirs.Recently,Han et al.illustrated that D.tuberspinifera is an active and agile hunting carnivore that can capture swimming prey including micro-particulates,rotifers,and other metazoans.In previous studies,however,the specimen identifications were done by microscopic examination,which requires a broad and deep taxonomic knowledge and is verylaborious,time-consuming,and somewhat variable because of insufficient taxonomic resolution.In order to facilitate the identification of diet composition in D.tuberspinifera,an inexpensive,efficient,rapid and easy-to handle gene clone library has been developed for diet detection and analysis.The plankton samples were collected from the Hubian Reservoir in Xiamen city in September of 2010.Individual cells were isolated using a glass capillary under an inverted microscope and washed 3—5 times with distilled water before DNA extraction and PCR amplification.The 18 S rRNA gene was amplified by the universal eukaryotic primers,and the purified PCR products were ligated into the p GEM-T vector and transformed into Escherichia coli DH5α-competent cells.In total,46 plasmids containing target gene fragments were successfully identified and sequenced.Each sequence was compared with sequences available in the Gen Bank database using BLAST,and the closest relatives were identified for diet or food composition analysis.Finally,11 OTUs( operational taxonomic units) were identified at 97% sequence similarity level,and they belonged to either Rotifera( 52%) or Copepoda( 48%).Our results,combined with existing data,suggested that:1) the diet composition of Difflugia tuberspinifera is composed of both rotifera and copepoda species;2) unicellular protozoa are not only the food of metazoa,but they can also prey on multicellular micro-metazoa;3) molecular methods are universally applicable,and the SSU rRNA( small subunit ribosomal RNA) gene clone library is an efficient,rapid,and repeatable approach to study the diet composition of protozoa.国家自然科学基金项目(31172114;30800097); 福建省杰出青年科学基金项目(2012J06009

INFLUENCE OF SURFACE ROUGHNESS ORIENTATIONS ON FRICTION COEFFICIENT OF WHEEL/RAIL SPECIMEN IN OIL LUBRICATION

黏着力是列车安全与平稳运行的关键因素之一.最大黏着力与摩擦力有关,摩擦力的减小会导致黏着力的降低.表面粗糙度及其取向是影响摩擦系数的重要因素,然而,有关表面粗糙度取向对于混合润滑状态下摩擦系数的影响的研究结论似乎是矛盾的.用激光离散改性技术将车轮试样表面制备成具有菱形、纵纹、横纹3种典型的形貌,并且与不作激光离散改性处理的车轮试样作对比,用基于确定性模型的统一雷诺方程数值分析法和小比例尺度的轮轨试样摩擦学实验,得到的结论是:在油润滑状态下,激光表面形貌大幅提高摩擦系数,其中菱形对应的摩擦系数最大,纵纹与横纹的摩擦系数相差不大,摩擦系数的大小主要取决于由表面粗糙度取向决定的接触区内粗糙峰接触压力与总压力之比,侧流效应也是影响摩擦系数的重要因素,它主要取决于接触区内表面粗糙度的取向

中草药用于酱油防腐初步研究

采用滤纸片法研究了118种中草药对酱油腐败菌毕赤氏酵母的抑制情况,考察了中草药的添加对酱油各项理化指标的影响,并以苯甲酸钠为对照,探讨其在酱油防腐效果方面的差异。结果表明,乌梅、丁香及石榴皮对酱油的防腐效果优于苯甲酸钠,并有助于改善酱油风味。其中,乌梅的最低抑菌质量浓度(MIC)及最低杀菌质量浓度(MBC)均为最小,分别达31.0 g/L和62.5 g/L

Ni/SiO2在甲烷部分氧化反应中的稳定性:W修饰的影响

甲烷部分氧化制合成气反应(POM)是天然气、页岩气资源利用的重要途径之一,常用的Ni/SiO2催化剂在反应中易发生表面积炭而失活。为了解决这一问题,我们采用尿素沉淀法制备W修饰的Ni基催化剂,并考察其在POM反应中的稳定性和W的作用。结果表明,催化剂中适量W的存在可显著改善其POM反应稳定性。其原因为Ni-W作用修饰了Ni的化学态或其亲氧能力,从而改善了其表面抗积炭能力。此外,反应中催化剂表面形成的α-WC具有一定的抑制表面积炭形成的能力,且该α-WC具有良好的稳定性。国家自然科学基金(21373169);;\n教育部创新团队(IRT1036)资助项目~