Monitoring of cadmium in "on" and "off" date palms

The study demonstrated that the mature dates we investigated were considered safe for human consumption. However, our findings revealed that much of the early fruit and leaves, which appeared at the advent of the fruiting season, possessed elevated levels of cadmium (Cd) that could accumulate in the food chain and thus impact adversely on the environment. In addition, animal feed for livestock contains date leaves, which should be restricted to the mature ones. The monitoring of cadmium in date palms is of considerable interest to environmental science and the thrust of this work, therefore, involved measurement, by ICP, of Cd in dates and corresponding leaf specimens, and evaluation of its distribution during the developmental stages of the fruiting season. Thirty-six date samples and 36 leaf specimens of the Fard cultivar were collected from "on" and "off" date palms during the Kimri, Bisir and Rutab stages of the fruiting season and subjected to suitable digestion procedures. Sample masses of typically 1 g (dry weight) were prepared in 25 ml dilute acid solution and investigated for trace levels of Cd by ICP-AES. Special attention was paid to contamination and the validation of our methodology. The Cd "threshold" in our study was 50 ng/g, in keeping with the levels of tolerance appearing in the literature. For the dates we found elevated levels of Cd [> 50 ng/g] in most of the samples, for both categories of "on" and "off" trees, during the Kimri stage. In the case of the leaves, the "on" samples revealed significant values up to 125 ng/g in Bisir, in some cases, but the trend for the "off" trees remained the same with the highest levels [> 100 ng/g] recorded during Kimri. Safe levels were attained during Rutab for all specimens. The possibility of a connection between Cd toxicity and the alternate-bearing phenomenon is discussed and this could be the subject of future interest.     

从“保护”到“回馈”——论环境法义务观的逻辑嬗变

传统环境法义务观存在三方面不足:义务的规定具有极强的政策性和宣示性;强调事先预防和事后治理的模式,缺乏事中控制:义务的架构缺失一种对自然的回馈机制.环境回馈义务是指人类对环境负有的回报和补偿责任,具体表现为涵养水源、植树造林、防沙治沙等积极地对环境进行投入的行为.环境回馈义务是一种积极义务,它要求必须对环境为一种积极的投入.环境回馈义务是一种生态法域的义务,它旨在构筑人与自然之间的和谐关系、维护生态系统整体的善,丰富和发展了环境保护义务的内容,体现了人类对自然内在价值的尊重.环境回馈义务的有效履行有利于实践中人与自然关系的和谐.人类对自然回馈是保持生态平衡的要求.实现人类对自然索取与回馈的平衡是符合生态经济发展规律的.生态整体主义的伦理观要求人对自然尊重和回馈.环境回馈义务也是生态正义的要求.     

从"两条主线论"考察中国文明进程

以可持续发展理论审视,在中国文明的发展进程中,除了存在传统史学所强调的“人与人”的关系这条主线外,还存在着“人与自然”关系的主线,本文以中国的若干重大历史事件为例证,初步论证了“人与人”和“人与自然”两条主线的相互作用关系是中国文明发展演变的主要驱动力。因此,实现人与人关系的公平和人与自然关系的和谐,是实现可持续发展的前提。     

"Healthy" eye in office-like environments

Eye irritation symptoms, e.g. dry eyes, are common and abundant symptoms reported in office-like environments, e.g. aircraft cabins. To improve the understanding of indoor related eye symptomatology, relevant knowledge from the ophthalmological and indoor environmental science literature has been merged. A number of environmental (relative humidity, temperature, draft), occupational (e.g. visual display unit work), and individual (e.g. gender, use of cosmetics, and medication) risk factors have been identified, which are associated with alteration of the precorneal tear film (PTF); these factors may subsequently exacerbate development of eye irritation symptoms by desiccation. Low relative humidity including reduced atmospheric pressure further increases the water evaporation from an altered PTF; in addition, work with visual display units may destabilize the PTF by lower eye blink frequency and larger ocular surface. Results from epidemiological and clinical studies support that relative humidity >40% is beneficial for the PTF. Only few pollutants reach high enough indoor concentrations to cause sensory irritation of the eyes, while an altered PTF may exacerbate their sensory effect. Sustained low relative humidity causes impairment of the PTF, while its stability, including work performance, is retained by low gaze and intermittent breaks.     

天保、退耕工程与环境可持续发展的关系

天然林保护、退耕还林还草工程是人类生存哲学的革新,是可持续发展思维方式的具体实践。其目的在于改善人类生存环境,达到人和环境的协调统一,实现人类与环境的可持续发展。探讨了两大工程顺利推进并充分发挥生态效益的因素：（1）加强生态文明建设;（2）坚持生态效益优先原则;（3）加强恢复生态学基础理论研究,制定科学的工程评估和监测标准;（4）建立和完善生态补偿机制;（5）完善工程机构建设;（6）完善生态环境保护的法律、法规及办法。     

广义“资源诅咒”的理论内涵与实证检验

越来越多的研究发现,自然资源富集的国家或地区往往拥有较缓慢的发展速度,似乎丰富的自然资源反而阻碍了经济的发展,造成一国或地区经济的不可持续发展,即前人所说的"资源诅咒".回顾文献发现,前人对"资源诅咒"本质、发生机制等的研究均集中反映的是自然资源与经济增长的关系,而本文在此基础上提出了广义"资源诅咒"的概念,从诅咒发生的主体、客体、传导机制等几方面定义了广义"资源诅咒"的理论内涵,并选取山西省作为典型案例进行了传导机制与诅咒现象的耦合关系分析,最终得出结论:长期来看,对自然资源过分依赖的国家或地区很有可能陷入经济发展滞后,社会问题突出.生态环境不断恶化以及资源快速耗竭的困境,成为实际意义上的不可持续的国家或地区,不只是经济上的不可持续,此即本文所主张的广义"资源诅咒"的理论内涵.     

企业发展的"环境-资源"平衡战略

本文分析了关于企业发展的两种观点：企业环境决定论和企业资源决定论；提出了实现企业发展的“环境-资源”平衡战略的理念；为了达到企业环境与资源两者的整合和平衡，保持持续竞争优势，企业应以创新为核心，确立核心业务，重视组织的学习，作为一种特殊的企业资源，企业家精神和能力对企业的生存和发展起着重要作用。     

Levels of "toxic" and "essential" metals in samples of bovine milk from various dairy farms in Calabria, Italy

The aim of this research was to evaluate the possible contamination by heavy metals of milk from cows bred on various farms in Calabria. The concentrations of heavy metals were determined in 40 samples of bovine milk from the various dairy farms. Each sample, homogenized and powdered, was mineralized in a microwave oven. Quantitative analyses of Cd, Cr, Cu, Pb and Se were performed using an atomic absorption spectrophotometer with graphite furnace; As was analyzed by hot vapor generation technique and Zn with the flame method. As regards toxic heavy metals, highest values are those of As (g.m. 37.90 microg/kg w.w.) and Pb (g.m. 1.32 microg/kg w.w.), while lowest concentrations are those of Cd (g.m. 0.02 microg/kg w.w). With regard to essential metals, Zn (g.m. 2016 microg/kg w.w) and Se (g.m. 13.24 microg/kg w.w.) showed the highest concentrations, followed by Cr (g.m. 2.03 microg/kg w.w.) and Cu (g.m. 1.98 microg/kg w.w.). Further investigations of the levels of heavy metals (As) in a greater number of milk samples from various zones of Calabria are necessary, both to examine this problem from the clinical epidemiological point of view and to identify the possible causes of milk contamination.     

“土地城市化”向“人口城市化”转变——一个分析框架及其政策含义

本文将人口变量引入城市用地扩张的理论模型中,以级差地租收益分配为核心,剖析了人口增长与用地扩张之间的互动关系。研究发现,在政府主导的城市化发展中,受发展竞争驱动,地方政府将城市中决定用地规模的经济活动人口和享有公共物品的户籍人口割裂开来:一方面,尽可能多的扩张城市用地面积以容纳更多的经济活动人口、攫取地租收益;另一方面,在级差地租分配中,拒绝让非户籍移民以公共物品的形式分享城市增长中的级差地租收益,从而降低城市化发展的成本。地方政府在享有外来人口集聚带来的级差地租收益的同时却不必承担相应的公共物品成本,这种成本收益计算中的扭曲进而导致了城市增长中的用地过度扩张、整体社会福利水平下降的问题。有鉴于此,在城市化相关改革政策中,应当引入人地统筹的调控思路,将级差地租收益分配与人口市民化问题相挂钩,有助于实现城市增长中的人地关系协调,抑制过度"土地城市化"并合理推进"人口城市化"。     

"资源诅咒"与资源型地区可持续发展

近年来,国际经济学界越来越多的学者认同"资源诅咒"的现象,并对此现象从政治、经济和社会等不同角度进行了解释.本文在回顾这些研究的基础上,从经济视角构建了一个包含资源部门、制造业和服务业三部门的动态模型,模型的动态过程显示,资源型地区经济在面临外部资源价格突然上升的冲击时,收入的提高使得家庭会同时增加制造品和服务品的消费支出,制造品的贸易性特征导致支出漏出到其它地区,服务品的非贸易性促使本地服务部门扩张,并从制造部门中吸收劳动与资本,制造业因而萎缩,资源型地区经济的长期增长因此受到损害.模型的政策含义是资源丰裕型地区要保持可持续发展必须制定严格的开采计划,杜绝过度开采;另外还需有计划地不断强化对制造业的支持和扶助,不断鼓励制造部门的技术创新,从而减少地区经济对资源部门的依赖,在资源枯竭之前,建立起强大的制造业基础.实现经济的可持续发展.     

Editorial foreword for "environment,development and sustainability" journal

Environment, Development and Sustainability -     

人类承载力"K值"影响因素

人类承载力“K值”表示地球能承载人口的极限值。“K值”的影响因素的繁多以及相互间的联系使得“K值”确切数值的计算成为一项非常艰巨的任务。通过分析人类与自然的关系，探讨人类承载力的微观影响因素及其相互关系，从开放生态系统的性质讨论人类承载力的宏观影响因素。从而得出人类承载力受渐变和突变因素的结合控制。以此揭开承载和调控人类种群的机理并预测“K值”的可能发展趋势，达到避免计算“K值”确切数值而又能提出人口增长对策和可持续发展的指导意见的目的。     

Residual radioactive contamination at the peaceful underground nuclear explosion sites "Craton-3" and "Crystal" in the Republic of Sakha (Yakutia)

In this paper, results are reported on the concentrations and activity ratios of 137Cs, 239+240Pu and 238Pu in soils, lichen and bottom sediments collected at the peaceful underground nuclear explosion sites "Craton-3" and "Crystal" (Republic of Sakha (Yakutia), North-East Siberia). At the "Craton-3" site, 239- 240Pu concentrations in the range 6.2 mBq/g to 5.9 Bq/g in surface soils (0-5 cm) and 239+240Pu concentrations up to 7.4 Bq/g in lichen were observed. The 137Cs concentration in measured soils range from 0.52 to 216 Bq/g for the near-plume and from 1.65 to 21.5 Bq/g for the far-plume. In lichen, 137Cs concentration varied from a global background level up to 251 Bq/g. Radioactive contamination at "Crystal" demonstrates an extremely irregular distribution of 239,240Pu and 137Cs in environmental samples taken at locations within 150 m radius of the site. Further work on compiling detailed maps of radioactive contamination of the territory around "Craton-3" and "Crystal" is discussed.     

基于“可持续性”要素的比较优势理论拓展

比较优势是不同国家生产同种产品的机会成本差异。传统理论认为,形成比较优势的机会成本主要为生产成本,而"可持续性"是一种代际公共品,耗费"可持续性"要素的机会成本是代际成本,即现在使用某(些)要素所放弃的未来使用之可能带来的纯收益。因此,不同国家的可持续性差异体现为代际成本差异,"可持续性"是塑造一国比较优势的新要素。若中国对外贸易过度依靠当代所具有的劳动力价格低廉和环境规制政策宽松所塑造的劳动力比较优势和环境比较优势,从长期看是不可持续的。通过代际成本内在化,可逐步实现对外贸易发展的短期理性与长期理性的统一。进而言之,中国需要妥善处理贸易增长与各种稀缺要素消耗之间的关系,平衡贸易增长与可持续发展的关系,当今的贸易与未来的贸易需寻求某种总量和结构上的均衡。     

中国西藏开发中的"长江战略"问题研究

西藏地处我国西部，西藏开发是西部大开发的重要组成部分。通过对长江经济带和西藏开发的关系及西藏发展的历史、现状和问题的分析，认为长江经济带有能力，也有必要支持西藏自治区的发展。根据西藏目前的发展现状和存在的问题来看，长江经济带有必要在新的背景条件下，寻求更好的战略模式促进西藏开发，即同西藏两地通过文化交流促进经济融合，以改变观念为出发点，拓展潜在市场为目标，达到促进西藏开发和长江经济带进一步的双重目的。长江战略的实施要点包括：（1）推广双语学习，以文化交流促进经济融合。（2）提高藏语教学的师资质量，改善劳动力整本素质；（3）让一部分藏民先富起来，成为西藏开发的中坚力量；（4）合作协助发展交通、通讯等基础设施，完善交流手段；（5）帮助扶植西藏地区的起步产业，逐步培养自立发展经济的能力。     

黄河口治理与“三约束”理论

黄河口治理是黄河治理的重要问题之一,黄河口治理观点有河口提动论、河口相对稳定论、固住河口论。本文分析了固住河口的必要性和可行性,提出了“三约束”理论,认为黄河口治理关键是固住河口。     

环杭州湾"葡萄串"式组合城市研究

环杭州湾上海、杭州、宁波等六城市，城市之间社会、经济相互联系密切，交通等基础设施日益完善，特别是杭州湾大桥的建设，形成了沪、杭、甬之间的两小时交通“金三角”区，当今世界城市群、城市带、城市圈在各地兴起，杭州湾地区完全有可能形成环杭州湾“葡萄串”式组合城市。本文在分析杭州湾城市发展现状和城市组合重要作用的基础上，提出了环杭州湾组合城市空间布局的设想。     

环杭州湾“葡萄串”式组合城市研究

环杭州湾上海、杭州、宁波等六城市 ,城市之间社会、经济相互联系密切 ,交通等基础设施日益完善 ,特别是杭州湾大桥的建设 ,形成了沪、杭、甬之间的两小时交通“金三角”区。当今世界城市群、城市带、城市圈在各地兴起 ,杭州湾地区完全有可能形成环杭州湾“葡萄串”式组合城市。本文在分析杭州湾城市发展现状和城市组合重要作用的基础上 ,提出了环杭州湾组合城市空间布局的设想。