不同类型土壤镉含量对香芋镉吸收的影响

为探明香芋(Colocasia esculenta)镉(Cd)超标的关键原因,在湖南临武香芋主产区分别选择紫色页岩和第四纪红壤发育的Cd污染水稻土,研究土壤Cd含量、Cd活性及土壤基本理化性质对香芋Cd吸收的影响,以期为香芋的安全种植提供技术支撑。结果表明,两个试验点所有香芋Cd质量分数皆超过食品安全国家标准(0.1 mg·kg^-1),且各试验点内田块间土壤Cd含量、pH差异显著,而土壤有机质和阳离子交换量变异较小;紫色页岩发育的中碱性水稻土壤Cd活性、Cd在土壤-香芋系统中的转移系数(TFstem/taro、TFtaro/soil)皆低于第四纪红壤发育的酸性水稻土;紫色页岩发育的中碱性水稻土中,香芋Cd含量主要受土壤全Cd、TFtaro/soil的正调控;而第四纪红壤发育的酸性水稻土壤中,香芋Cd含量既受土壤全Cd、DTPA-Cd、TFtaro/soil的正调控,还受土壤pH的负调控。为实现香芋的安全生产,紫色页岩发育的中碱性水稻土中,应优先选择Cd吸收能力较低的香芋品种,或选择土壤全Cd低于0.65 mg·kg^-1的土壤进行种植;而在第四纪红壤发育的酸性水稻土壤中,则可优先选择Cd吸收能力较低的香芋品种,或选择土壤全Cd含量低于0.41 mg·kg^-1的土壤,或调理土壤pH至6.26以上,以及钝化土壤DTPA-Cd至0.19 mg·kg^-1以下的技术措施,抑制土壤Cd向香芋的迁移转运。     

从接受主体看文学价值的永恒性

价值是客体的属性对主体需要的满足.主体需要是在实践中产生的,是价值关系的主动条件.文学作品的价值就是文学作品的属性满足接受主体的精神需要.人类的自由需求是共同的,而美是自由的感性显现.文学作品的价值永恒性就是其审美属性满足主体需要---人的共同自由需求.     

高校人事档案管理现代化之我见

高校人事档案工作是高校教育事业重要的组成部分,是高校管理体制改革的需要.现在高校人事档案管理存在诸多问题,高校人事档案管理的现代化十分必要.解决这些问题,高效的为高校教学、管理和各项工作提供优质服务,是高校人事档案管理现代化的方向和要求.参4.     

浅谈言语模仿与广告中的仿译

模仿是人类生活中普遍存在的一种现象,是影响人际关系的重要形式.言语模仿是人类模仿中的一种.人们往往对自己所喜欢而且对自己有着强烈吸引力的语言进行自觉或不自觉的模仿.通过研究人的模仿心理,分析广告词的模译,试图证明模仿是语言学习的重要途径和语言创造的基础.     

球迷闹事的伦理思考

球迷闹事行为是在集体的冲动影响下的共同行为,是一种集体无意识的表现.从伦理学的角度来说,是个体由于社会价值观混乱等因素而表现出的一种缺乏道德修养的行为.因此,提高球迷道德修养、充分发挥诚信的作用,成为一个值得探索的伦理问题.参9.     

校园廉政建设——高校和谐校园的保证

高校和谐校园是构建社会主义和谐社会的组成部分,但高校腐败现象已不一而足,是有悖校园和谐的,名利是滋生高校腐败的温床.因此,如何树立正确的名利观、加大校园的反腐力度具有极其重要的现实意义和研究价值.参5.     

中国传统诚信观与大学生诚信教育

诚信是我国传统道德的重要规范,注重诚信是中华民族的道德传统,中国传统的诚信观特点有二,一是诚信是一个人立身处世之本;二是诚信是交友的基本道德准则.当代大学生诚信滑坡,迫切需要进行诚信教育.传统的诚信观教育,有助于大学生从本体价值的高度来重视提高自身的道德修养.可以通过在大学普遍开设以诚信为核心内容的传统文化教育通识课程、努力提高教师的传统文化素养和营造社会诚信的大环境等方式来加强大学生诚信教育.参7.     

对高职创业教育的思考

当代科学技术的发展和社会经济结构、就业结构的变化,急切呼唤各类职业技术院校开展创业教育,培养创业型人才.创业教育是培养学生的创业意识、创业个性品质、创业能力,使其具有创业者人格的教育.在实施教育过程中,让学生具有正确的思想动力是前提,提高创业能力是根本、方法得当、措施得力是保证.开展创业教育,有助于素质教育的全面推进.     

三峡库区不同植被覆盖对土壤碳的影响

植被覆盖变化对三峡库区生态环境产生重要影响.土壤有机碳在陆地生态系统的发育和运行等方面均起着极其重要的作用,所以本课题研究宜昌点军区柏树地,橘树地以及菜地的土壤性质状况.结果表明:土壤含水量是柏树林最大.菜地的最小,而土壤容重的大小顺序是:柑橘树地>柏树地>菜地.土壤有机碳、易氧化碳和二者的比值都是柏树地的最大,柑橘地的最小,菜地的处于中间状态.而微生物碳和微生物墒含量大小顺序是柏树地>柑橘树>菜地;微生物代谢墒的大小顺序是:柑橘地>菜地>柏树地.由此说明柏树生长有利于土壤活性碳源含量的提高和土壤质量的改善.     

企业战略执行体系的构建与运行

企业战略执行,是指企业实行战略的具体计划、行动和控制过程.它包括企业战略执行的基本原则、适度的合理性原则、统一领导统一指挥的原则、权变原则等.战略执行是以提升企业战略分析和预见、战略选择与设计、战略有效实施和优化为目的体制保障.战略执行系统最关键的是战略信息系统,战略计划系统,战略动力系统,战略反馈系统.参5.     

Nanosensors and nanobiosensors in food and agriculture

The food and agriculture sector controls the economic growth of a developing country. The food industries have practices of growing crops, raising livestock and sea foods, food processing and packaging, regulating production and distribution with quality and safety. The process control and monitoring quality are crucial steps. Here we review nanosensors and nanobiosensors as alternative of classical quantification methods. Nanoscale dimensions of metal nanoparticles, metal nanoclusters, metal oxide nanoparticles, metal and carbon quantum dots, graphene, carbon nanotubes, and nanocomposites expand the sensitivity by signal amplification and integrate several novel transduction principles such as enhanced electrochemical, optical, Raman, enhanced catalytic activity, and superparamagnetic properties into the nanosensors. The electrochemical nanosensors, optical nanosensors, electronic nose and electronic tongue, nanobarcode technology, and wireless nanosensors have revolutionized the sensing in food and agriculture sectors with multiplex and real-time sensing capabilities. Despite previous success stories of the remunerative health sector, the approaches are transferred subsequently to food and agriculture sector; with potential application in detection of food contaminants such as preservatives, antibiotics, heavy metal ions, toxins, microbial load, and pathogens along with the rapid monitoring of temperature, traceability, humidity, gas, and aroma of the food stuff.     

市场经济与土肥科技

土肥的基础地位是不随社会性质或社会经济类型的变化而变化的，它既具重要性，又具长久性．市场经济是仍然需要土肥科技的．土肥科技的教学、科研和推广的力度必须加大，局面必须改观，且宜快不宜迟．土肥科技工作者一定要将培肥地力作为中心工作．根据广东的实际，增施有机肥是培肥地力的主要措施，因而抓秸秆还田和发展冬绿肥是我们工作的重点．     

基因污染与生态环境安全

论述了基因污染可能对生态环境安全造成的影响。转基因作物有可能污染天然物种的基因库；有可能破坏传统农作物品种的遗传多样性，加速作物种植品种的单一化及基因资源的流失；使抗除草剂作物的基因向野生或半野生植物漂移的可能性加大，有可能创造出“超级杂草”；带有病毒型转基因作物的基因重组，有可能创造出新的植物病毒，导致新的病害；BT转基因抗虫作物分泌的毒素，在食物链中传递，很难加以控制，对非目标生物造成危害，并最终破坏自然生态系统的平衡。文章还从不同角度分析了基因污染的严重性。     

1株贫营养好氧反硝化菌的分离鉴定及其脱氮特性

从水库底泥样品中,以硝酸盐为唯一氮源进行驯化、分离筛选出1株能在贫营养及好氧条件下进行高效反硝化的菌株PY8,经过电镜形态学观察、生理生化和16S rDNA序列分析,并基于16SrDNA序列结果,构建了该菌株的系统发育树,最终确定菌株PY8为根瘤菌Rhizobiumsp.。考察了初始pH值、温度、C/N、初始硝酸钠质量浓度、投菌量对菌株PY8硝酸盐还原活性的影响,以及该菌株的异养硝化性能。结果表明,在pH6.0～10.0,温度25～30℃,C/N1.0～9.0,初始硝酸钠质量浓度0.01～0.50g·L-1,投菌量1%～15%时,菌株PY8培养72h后的硝氮去除率可达到95%以上。另外,该菌株具有同时硝化-反硝化作用,在培养过程中氨氮去除率可达到58%左右。实验结果表明,菌株PY8在微污染水体生物脱氮领域中具有很大的应用潜力。     

Indoor and outdoor air pollution and lung cancer in New Hampshire and Vermont

Indoor and outdoor air pollution is known to contribute to increased lung cancer incidence. This study is the first to address the contribution of home heating fuel and geographical course particulate matter (PM₁₀) concentrations to lung cancer rates in New Hampshire, USA. First, Pearson correlation analysis and geographically weighted regression were used to investigate spatial relationships between outdoor PM₁₀ and lung cancer rates. While the aforementioned analyses did not indicate a significant contribution of PM₁₀ to lung cancer in the state, there was a trend towards a significant association in the northern and southwestern regions of the state. Second, case-control data were used to estimate the contributions of indoor pollution and secondhand smoke to the risk of lung cancer with adjustment for confounders. Increased risk was found among those who used wood or coal to heat their homes for more than 10 winters before the age of 18, with a significant increase in risk per winter. Resulting data suggest that further investigation of the relationship between heating-related air pollution levels and lung cancer risk is needed.     

Characteristics of dispersions and water-soluble extracts of crude and refined oils and their toxicity to estuarine crustaceans and fish

The quantitative hydrocarbon composition and behavior in seawater of water-soluble fractions (WSF) and oil-in-water dispersions (OWD) of 4 oils was investigated. Two crude oils, South Louisiana crude and Kuwait crude, and two refined oils, No. 2 fuel oil and bunker C residual oil, were used in these investigations. The WSFs of the crude oils had higher total oil-hydrocarbon concentrations and were richer in light aliphatics and single-ring aromatics than were the WSFs of the refined oils. The WSFs of the refined oils contained significantly higher concentrations of naphthalenes than did those of the crudes. The hydrocarbon composition of the aqueous phase of OWDs closely resembled that of the parent oils. Gentle aeration of the OWDs resulted in a loss of 80 to 90% of the aqueous hydrocarbons in 24 h. Alkanes disappeared from the dispersions more rapidly than aromatics. The WSFs and OWDs of the refined oils were considerably more toxic to the 6 test species than were those of the crude oils. The test species can be ranked according to increasing sensitivity to oil as follows: Cyprinodon variegatus, Menidia beryllina, Fundulus similus, Penaeus aztecus postlarvae, Palaemonetes pugio and Mysidopsis almyra. The results of this investigation are discussed in relation to the potential impacts of oil spills on the marine and estuarine environments.