人类活动对珠江三角洲酸性硫酸盐土壤发育的影响

In the Pearl River Delta with more than 1000 years of intensive land reclamation history,the development of acid sulphate soils has been generally limited in terms of their acid potential (pyrite content)and spatial extent.This is attributed to the rapid delta progradation,partially resulted from increasing sediment yield caused by deforestation within the catchment and the empolderment in the estuarine embayment.The empolderment practice accompanied by the clearance of mangroves stopped the upward growth of the pyritic layer on the one hand and limited the vertical accretion of non-pyritic freshwater sediments over the pyritic layer on the one hand and limited the vertical accretion of non-pyritic freshwater sediments over the pyritic estuarine sediments on the other.In such a case,the pyritic layer in the area is frequently thin and of shallow occurrence.Under forced leaching-recharge conditions for the paddy rice cultivation ,the leaching of acid sulphate materials prevails over its production and this leads to a net loss in pyrite oxidation products.Land excavation for fishpond farming accelerates pyrite oxidation due to the direct exposure of the pyrtic sediments to air on the pond bunds.Severe acidification can intensity the environmental degradation of estuarine ecosystems.     

Schisandrin B protects against solar irradiation-induced oxidative injury in BJ human fibroblasts

The effects of schisandrin B (Sch B) and its analogs on solar irradiation-induced oxidative injury were examined in BJ human fibroblasts. Sch B and schisandrin C (Sch C) increased cellular reduced glutathione (GSH) level and protected against solar irradiation-induced oxidative injury. The photoprotection was paralleled by decreases in the elastases-type protease activity and matrix-metalloproteinases-1 expression in solar-irradiated fibroblasts. The cytochrome P-450-mediated metabolism of Sch B or Sch C caused ROS production. The results suggest that by virtue of its pro-oxidant action and the subsequent glutathione antioxidant response, Sch B or Sch C may offer the prospect of preventing skin photo-aging.     

Investigation into the population growth and its implications for primary schooling in Timor‐Leste by 2020

The nation‐building process of Timor‐Leste, the newest nation in Asia, faces significant demographic challenges due to its high population growth, which is the fastest in Asia. The major contributor for this unprecedented growth is the extremely high total fertility rate of Timor‐Leste, among the highest in the world. It is of great concern that if the current fertility rate and its implied population growth continue the population of Timor‐Leste will double in 17 years. The analysis in this paper clearly shows that the current extremely high dependency ratio will decline only marginally in the next 10 years and this will put tremendous pressure on the government to constantly keep up with the increasing number of children entering school every year. However, as the intrinsic value of human resource development feeds back into the overall society and economy, an adequate public investment in knowledge‐producing services at the earliest stages of life and throughout that life has the potential to change the demographic concern of Timor‐Leste into a future demographic dividend.     

Feature extraction and recognition technique for human pulse signals

In Chinese traditional medicine, the pulse signal plays an important role for diagnosis. To investigate the effective technique for identifying heroin druggers through the pulse signal, the feature extraction algorithm based on the biocepstrum and the third-order cepstrum entropy of the pulse signal is studied. On the basis of concise and rigorous discussion for the algorithm, the biocepstrum-based diagonal slice components are estimated for human pulse signals of 20 heroin druggers and 20 healthy normal subjects. The magnitude of the sample value of diagonal slice at m=n=1 and the third-order cepstrum entropy of magnitudes of sample values of the diagonal slice within a particular region are used as two feature parameters for every human pulse signal to form a feature vector. A classifier based on the criterion of squared Mahalanobis distance is successfully designed. Applying the designed classifier to 40 feature vectors, the correct identification rate reaches 87.5%. The research result shows that the method of the feature extraction and classifier design presented in is valuable for identifying the human pulse signals of heroin druggers.     

我国农村生育率对家庭人力资本的影响与对策

利用统计年鉴数据对我国农村生育率对家庭人力资本的影响进行实证分析,表明随着农村生育率下降,农村居民家庭人力资本呈现出不断上升趋势。在分析制约农村生育率下降迟缓的深层次经济与社会文化因素的基础上,提出应发展农户经济,改变农村生产经营方式,加快农村城市化进程,加快农村社会养老保障建设等对策,以降低农村生育率。     

人类胚胎干细胞与小鼠囊胚嵌合的探讨

【目的】探讨人类胚胎干细胞(Human embryonic stemcells,hESCs)能否在小鼠胚胎环境中生存并参与其各个组织器官的分化,为hESCs与小鼠囊胚嵌合的可行性研究提供依据。【方法】将154枚受精后3.5 d(3.5days postcoitum,3.5 dpc)ICR品系小鼠囊胚随机分为3组:试验组(注射hESCs)、模拟注射组(注射针仅刺破透明带及滋养层细胞,但不注射细胞和溶液)及对照组(未注射),于注射后培养24 h统计囊胚完全孵化率。将稳定转染增强绿色荧光蛋白(Enhanced green fluorescent protein,EGFP)的含有9~15个hESCs的小细胞团块,显微注射入3.5 dpcICR品系小鼠囊胚腔内,注射后分别于3,24,48,69,77,94和116 h,在普通荧光显微镜下观察EGFP阳性细胞的定位与动态分布情况,并将嵌合体胚胎移植入假孕母鼠子宫内,分别于移植后第4天和第6天处死孕鼠,普通荧光显微镜下观察EGFP阳性细胞在整个小鼠胚胎中的分布情况。【结果】注射后24 h,试验组和模拟注射组的囊胚完全孵化率分别为73.6%和77.1%,均极显著高于对照组(38.3%)(P<0.01),有88.9%(32/36)的胚胎中的hESCs迁移并定位在小鼠内细胞团(ICM)及其临近的滋养层细胞上;体外培养48 h后,EGFP阳性细胞数进一步减少;116 h后,只有1枚胚胎仍残留3~4个EGFP阳性细胞,且散在分布于ICM克隆之外。体内发育试验结果显示,将43枚注射后的嵌合体囊胚移植入6只代孕母鼠子宫内,获得了22枚脱膜,有17枚脱膜中含有胚胎,其中形态正常胎儿14枚,没有胚胎含有EGFP阳性细胞。【结论】hESCs很难与小鼠囊胚正常嵌合。     

大力开发农村人力资源 夯实延边农业发展的根基

分析了延边朝鲜族自治州农业发展的优劣势条件及开发农村人力资源与农业发展的关系，提出了开发农村人力资源的对策和建议。     

容积性饲料对阴离子盐作用效果影响的研究

试验选用干奶后期奶牛10头,探讨干奶期奶牛应用阴离子盐产生效应所需的条件.收穗后青刈玉米秸与小麦秸作为大容积性饲料,尿液pH易达到阴离子盐产生效应的状态,而萨拉秧与苜蓿干草则不易达到.不同大容积性饲料,阴离子盐的适宜添加量不同,收穗后青刈玉米秸、苜蓿干草的适宜添加量为每头440-500 g/d,小麦秸则为每头440 g/d.将添加的阴离子盐分成两部分,一部分与精料均匀混合,另一部分先溶于少量水,再均匀喷洒于大容积性饲料表面进行饲喂,可避免阴离子盐对采食量的影响.     

城市森林对热污染及人体舒适度影响的研究

系统研究了城市森林对热污染的影响。结果表明，城市森林可改变下垫面性质，有效地减少到达地面的太阳辐射，在片林和林荫道下，夏季能降低气温３℃左右，路面温度７℃，建筑物表面温度４～１０℃，减少高温持续时间３～８ｈ左右。不同绿化形式，不同行道树结构，不同树种的降温效应不同，作者根据人体对气候要素的综合反应，建立了夏季城市森林对人体舒适度小气候函数方程，为城市森林效益评价提供了理论依据。     

思想政治教育需要及其激发和培养探析

人的需要是人的能动性最原初的动力。解决当前思想政治效果不佳的问题 ,从根本上也要从激发思想政治教育的需要入手。分析了思想政治教育需要的涵义、意义。提出思想政治教育必须遵循人的需要的发展规律。当前条件下 ,激发和培养人的思想政治教育需要 ,基础在于发展社会生产力 ,满足人民基本的物质生活需要 ,为思想政治教育奠定坚实的物质基础 ;关键是要完善思想政治教育内容体系 ,增强思想政治教育内容的渗透力和说服力 ;最直接的方法是惩治腐败 ,树立党的良好形象