Evaluation of alternative models of commitments and job attitudes of professionals

Different and sometimes contradictory assumptions can be found in the literature about the relationships between the commitments of professionals to their profession and to the employing organization, and the consequences of these relationships for other work attitudes. Two of the basic alternative theoretical formulations are examined and their viability tested on a sample of 1206 accountants. One formulation assumes inconsistency between commitments leading to a commitment dilemma, the other assumes congruity between them. The findings point at the latter formulation as the more viable one, and suggests minor modifications in it to improve its fit with the data. The results demonstrate the need to compare competing models in order to increase theoretical clarity and consistency.     

Content and distribution of forms of organic N in soil and particle size fractions after long-term fertilization

Most of the N in surface soils occurs in organic forms, and when mineralized it plays a key role in soil fertility and plant nutrition. Our objective was to study the effect of long-term applications of organic manure on the content and distribution of forms of organic N in bulk soil and soil particle size fractions to characterize the inherent soil nitrogen fertility. Five treatments were as follows: (1) CK (no fertilizer and no manure added), (2) mineral fertilizer only, (3) straw + NPK, (4) green manure + NPK and (5) pig manure + NPK. Soil particle size fractions (0-2, 2-10, 10-50 and 50-100 microm) were isolated without chemical pretreatment by ultrasonic dispersion in water followed by sedimentation. The content of total N and forms of organic N in the bulk soil increased after long-term fertilization, and the effect varied with fertilizer type. The plot treated with only mineral fertilizer gave the highest NH3-N and the lowest amino sugar-N content in all treatments. The highest content of amino sugar-N and amino acid-N was found in the treatment of pig manure + NPK. The content (g kg(-1) fraction) of hydrolysable N within size fractions was in the order 0-2 > 2-10 > 50-100 > 10-50 microm, but the contribution of different size fraction to hydrolysable N decreased in the sequence 10-50 > 0-2 > 2-10 > 50-100 microm. Most of the applied mineral fertilizer N that remained in soils was distributed in the particle size fraction < 2 microm while most of the remaining N from manure applied with NPK was transferred into amino sugar-N in each size fraction, and amino acid-N in the size fractions > 2 microm during the process of humification.     

Size effect of Pt nanoparticles in acid-assisted soot oxidation in the presence of NO

Pt/Al₂O₃ catalysts with mean Pt particle size ranged from 2.7 to 7.1 nm were synthesized by chemical reduction method, and the sulfated counterparts were prepared by impregnation of sulfuric acid. The turnover frequency of platinum for soot oxidation under loose contact conditions in a feed flow containing NO and O₂ are positively correlated with the size of platinum. The sulfated Pt/Al₂O₃ exhibits higher catalytic activity for soot oxidation in the presence of NO despite their reduced ability for NO₂ production. Such a contradiction is more significant for those catalysts with smaller platinum particles. Herein, the catalysts were characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), transmission electron microscopy (TEM), inductive coupled plasma (ICP) emission spectrometry, CO chemisorption, thermogravimetric analysis (TGA), NH₃ temperature-programmed desorption (NH₃-TPD), NO temperature-programmed oxidation (TPO) and NO_x temperature-programmed desorption (TPD). Possible effect of Pt particle size for the catalytic oxidation of soot in the presence of NO was presented based primarily on the promoted NO₂ transfer efficiency onto the soot pushed by the acidic catalysts.     

Microbe-mediated sustainable bio-recovery of gold from low-grade precious solid waste: A microbiological overview

In an era of electronics, recovering the precious metal such as gold from ever increasing piles of electronic-wastes and metal-ion infested soil has become one of the prime concerns for researchers worldwide. Biological mining is an attractive, economical and non-hazardous to recover gold from the low-grade auriferous ore containing waste or soil. This review represents the recent major biological gold retrieval methods used to bio-mine gold. The biomining methods discussed in this review include, bioleaching, bio-oxidation, bio-precipitation, bio-flotation, bio-flocculation, bio-sorption, bio-reduction, bio-electrometallurgical technologies and bioaccumulation. The mechanism of gold biorecovery by microbes is explained in detail to explore its intracellular mechanistic, which help it withstand high concentrations of gold without causing any fatal consequences. Major challenges and future opportunities associated with each method and how they will dictate the fate of gold bio-metallurgy from metal wastes or metal infested soil bioremediation in the coming future are also discussed. With the help of concurrent advancements in high-throughput technologies, the gold bio-exploratory methods will speed up our ways to ensure maximum gold retrieval out of such low-grade ores containing sources, while keeping the gold mining clean and more sustainable.     

岩溶流域地表水和地下水硝酸盐来源定量识别

选取岩溶地区花溪河流域典型农业区为研究对象,运用δ¹⁵N-NO₃^-,δ¹⁸O-NO₃^-和δ¹⁸O-H₂O同位素示踪技术和水化学分析方法,阐明了研究区地表水和地下水中硝酸盐的分布特征,并揭示其来源和形成过程,基于R语言下运行的贝叶斯模型（stable isotope analysis in R）,对研究区水体中各种硝酸盐来源的贡献比例进行了定量识别.结果显示：受碳酸岩盐风化的控制,流域内地表水和地下水的水化学类型以HCO₃-Ca型为主,硝酸盐在研究区水体中的空间分布特征受土地利用类型影响明显;在研究区水体硝酸盐形成过程中,硝化作用起主导作用,水体中的硝酸盐来源主要有化肥、降雨中的氨盐、土壤有机氮、粪便和污水,与地表水相比,地下水中硝酸盐受粪便和污水的影响较大;基于SIAR源解析模型分析,大气沉降、化肥、土壤有机氮和粪便污水对研究区地表水硝酸盐的贡献比例分别为3.97%、26.87%、36.80%和32.37%,对地下水硝酸盐的贡献比例分别为2.83%、13.96%、21.03%和62.18%.     

喷施锌肥对油菜镉锌生物可给性的影响

采用溶液培养和体外消化实验,研究不同Zn营养条件下,喷施ZnSO_4和ZnNa_2EDTA对两种油菜Cd、Zn质量分数以及生物可给性的影响,计算人体通过食用油菜摄入Cd、Zn的量,评估喷施Zn肥降低人体Cd摄入提高Zn吸收的潜力.结果表明,正常Zn营养下油菜地上部Cd质量分数显著低于缺Zn条件下,喷施ZnNa_2EDTA显著降低油菜Cd质量分数;正常Zn营养下油菜地上部Zn质量分数显著高于缺Zn条件下,喷施Zn肥可显著提高油菜Zn质量分数,其中喷施ZnSO_4处理效果最佳.正常Zn营养下油菜Cd的生物可给性显著低于缺Zn条件下,喷施Zn肥显著降低油菜Cd在胃阶段的生物可给性,与对照相比最大降幅为35.81%,喷施ZnSO_4显著降低Cd在小肠阶段的可给性,最大降幅为59.24%;喷施Zn肥使油菜Zn在胃和小肠阶段的生物可给性显著低于对照处理,最大降幅为68.90%,其中ZnSO_4降低效果明显强于ZnNa_2EDTA.食用Cd污染的普通油菜寒绿摄入Cd的量超过世界卫生组织推荐的每日耐受值,通过选择低积累油菜华骏或喷施ZnSO_4可以显著减少人体摄入Cd的量,有效降低Cd过量摄入的健康风险;食用未喷施Zn肥或喷施低浓度ZnNa_2EDTA的油菜有Zn摄入不足的风险,而食用喷施ZnSO_4或高浓度ZnNa_2EDTA的油菜可以满足蔬菜膳食Zn摄入的需要,其中喷施ZnSO_4效果更好.总之,喷施Zn肥可显著降低油菜地上部Cd、Zn的生物可给性,有效减少人体食用油菜摄入Cd的量,提高摄入Zn的量,其中喷施ZnSO_4处理的效果最佳.     

四川省气候变化适应行动现状、问题和建议研究

作为遭受气候变化不利影响较为严重的省份之一,四川省面临着可持续发展能力提升和应对新增气候变化风险的挑战.文章在简要介绍气候变化对四川省的影响、系统梳理其在适应气候变化中取得成效的基础上,进一步剖析了存在的问题,最后结合四川省省情和气候变化适应行动现状,提出了从健全法律法规到完善适应气候变化的体制机制,从加强适应基础建设到强化适应能力建设等方面的建议.     

受限空间烟气运动盐水模拟研究的现状和展望

回顾了受限空间火灾烟气运动盐水实验模拟研究的发展历史;介绍了盐水实验模拟的理论基础及其在火灾烟气运动研究领域的应用情况和最新进展;分析和讨论了模拟研究过程中所存在的主要问题及其可能的解决方法。所有这些研究和探索,对于受限空间火灾烟气运动盐水实验模拟研究方法的创新和完善有重要的启发作用。     

东北地区烟尘(气)测试中一些问题的讨论

目前东北地区以燃煤为主要能源.烟尘(气)的排放仍是大气污染综合治理的主要空中对象.我们在采样过程中经常遇到这样那样的问题,根据GB5468-91锅炉烟尘测试法和个人的工作经验对问题出现的原因和解决方法进行简单的讨论.