沼气的减排效果和农户采纳行为影响因素分析

文章采用计量分析的方法,基于统计报表,对沼气减排效果进行分析。结果表明:2000年至2009年农村年平均沼气消费相当于替代标准煤的煤炭消费602.20万t,折算成煤炭,则相当于替代了843.423 8万t的煤炭消费量。以2009年为例,按照10美元/tCO2来计算,中国农村沼气替代煤炭减排CO2带来的收益为0.43亿美元。据估计,到2015年,我国农村户用沼气将达到233亿m3左右,加上规模化养殖场、养殖小区年产沼气6.7亿m3,共计239.7亿m3,相当于替代1 711.46万t标准煤,核计收益1.71亿美元。文章通过在我国沼气典型省份湖南省的160户农户调查问卷,建模分析包括农户基本情况、生产状况、心理认知、经济状况方面的20个变量对农户的沼气采纳行为的影响。结果表明,农户性别、年龄、是否参加协会、环境保护意识、是否有外来资金支持等因素对农户沼气采纳行为起到或正或负的影响。文章从减排的角度论证了进一步推进农村沼气建设的重要性,从农户行为影响因素的角度论证了推进农村沼气建设是一个复杂的系统工程,需要宣传、培训、服务、技术、协会、资金等方面的配套跟进。     

农户环境认知、行为决策及其一致性检验——基于江苏农户调查的实证分析

农业环境的改善,关键在于农户。通过对江苏省206个农户样本的调查,考察了农户环境认知及行为决策状况,并对两者的一致性进行了检验。研究表明：在以总分为6分的认知问题中,得分在35分以下的农户占到了样本总量的787%,表明部分农户的环境认知程度比较低;在以总分为5分的行为决策问题中,得分在3分及以下的农户占到样本总量的563%,表明部分农户决策过程中对环境的考量不足;受教育程度对样本农户环境认知和决策都有显著的影响,农户环境认知与决策之间并不存在显著的因果性,土地面积、受教育程度、年龄、性别以及主要收入来源等变量对农户环境认知及行为决策影响的差异,在一定程度上解释了这种不一致性     

Vaporization of heavy metals during thermal treatment of model solid waste in a fluidized bed incinerator

This paper investigated the volatilization behavior of heavy metals during thermal treatment of model solid waste in a fluidized bed reactor. Four metal chlorides (Cd, Pb, Cu and Zn) were chosen as metal sources. The influence of redox conditions, water and mineral matrice on heavy metal volatilization was investigated. In general, Cd shows significant vaporization especially when HCl was injected, while Cu and Pb vaporize moderately and Zn vaporization is negligible. Increasing oxygen concentration can lower heavy metal vaporization. Heavy metal interactions with the mineral matter can result in the formation of stable metallic species thus playing a negative effect on their behavior. However, HCl can promote the heavy metal release by preventing the formation of stable metallic species. The chemical sorption (either physical or chemical) inside the pores, coupled with the internal diffusion of gaseous metal species, may also control the vaporization process. With SO₂ injected, Cd and Pb show a higher volatility as a result of SO₂ reducing characteristics. From the analysis, the subsequent order of heavy metal volatility can be found: Cd > Cu ? Pb ? Zn.     

基于葛洲坝1号船闸模型的水流诱鱼试验研究

以鲢鱼(Hypophthalmichthys molitrix)为研究对象,在自制的葛洲坝船闸模型中,研究水流诱导鱼类进入船闸的技术。诱鱼效果采用鱼平均聚集率(P)、诱集效率指数(I)、通过闸门频次(f)和上下游停留时间比(Tr)作为评价指标。研究结果表明:适当范围的水流流速对诱导鱼类进入船闸有一定的诱集作用。当闸门断面平均流速为0.45 m/s时,诱集效率最高,此时鱼类在船闸两侧区域平均聚集率和诱集效率指数最大,通过闸门频次最高;当水流流速为0 m/s(对照组)时,鱼类的活动规律不明显;当水流速度大于0 m/s且小于0.45 m/s时,鱼群聚集中心主要集中闸门内高流速区域;当流速超过0.45m/s后,逐渐增大时,鱼类进入船闸的频率呈下降趋势,鱼群聚集中心主要集中在闸门下游侧流速较稳定的区域;当流速超过0.75 m/s后,鱼类的顶流行为逐渐减弱,不再呈现向闸门聚集的趋势,出现逃逸行为。通过本研究,为鱼类行为学的研究提供基础数据,同时为中低水头水利枢纽船闸与鱼道结合的可行性研究提供参考依据。     

Ambient ultraviolet radiation induces protective responses in soybean but does not attenuate indirect defense

We investigated the effects of ambient ultraviolet (UV) radiation on (i) the performance and chemistry of soybean plants, (ii) the performance of Spodoptera frugiperda and (iii) the foraging behavior of the herbivore's natural enemy Cotesia marginiventris which exploits herbivore-induced plant volatiles (VOC) for host location. The accumulation of protective phenolics was faster in plants receiving ambient UV than in controls exposed to sun light lacking UV. Accordingly, isorhamnetin- and quercetin-based flavonoids were increased in UV exposed plants. No UV effects were found on the performance and feeding behavior of S. frugiperda. Herbivore-damaged plants emitted the same VOC when grown under ambient or attenuated UV for 5, 10 or 30 days. Consequently, C. marginiventris was attracted but did not discriminate between exposed and unexposed soybeans. In summary, ambient UV radiation affected soybean morphology and physiology but did not destabilize interactions between trophic levels.     

The effect of workers' visibility on effectiveness of intervention programs: supervisory-based safety interventions

INTRODUCTION: This paper discusses an organizational change intervention program targeting safety behaviors and addresses important considerations concerning the planning of organizational change. Using layout of the plant as a proxy for ease of daily leader-member interaction, the effect of workers' visibility on the effectiveness of supervisory-based safety (SBS) interventions is examined. Through a reinforcement-learning framework, it is suggested that visibility can affect supervisors' incentive to interact with subordinates regarding safety-related issues. METHOD: Data were collected during SBS intervention studies in five manufacturing companies. RESULTS: Results suggest a reinforcement cycle model whereby increased visibility generates more frequent exchanges between supervisors and employees, resulting in improved safety behavior among employees. In turn, employees' safer behavior reinforces continued supervisory safety-related interaction. CONCLUSION AND IMPACT ON INDUSTRY: Visibility is an important moderator in supervisory based safety interventions, and can serve to increase workplace safety. Implications of these findings for safety are discussed.     

基于交通心理的行人不安全行为研究

基于交通心理学原理,对城市行人交通不安全行为进行研讨.分析了行人出行认知心理与行为的关系,给出行人信息处理过程的概念模型,指出行人的认知心理状态与交通事故关系密切.以定性分析的方法,把行人不安全行为归为有意和无意两类,从主客观方面分析行人心理对不安全行为的影响.通过实际交通调查及对实测数据的统计处理,表明行人交通安全意识淡薄,性别、年龄和有无驾照对行人交通安全意识有重要影响;系统分析了行人不安全行为的心理因素.从行人心理角度考虑,给出了一些相应的改善行人交通不安全行为的教育、管理、法制方面的建议和预防措施,例如:从行人心理角度对过街设施进行合理设置,从驾驶员心理角度考虑改善行人交通安全,对人行天桥和地道进行人性化设置等,将心理学行为矫正法原理应用于行人交通管理中.     

基于元胞自动机的弱视条件下群体疏散的仿真研究

根据人在弱视情况下的行为特征,建立基于元胞自动机的逃生模型,对弱视情况下的人群疏散进行了模拟。模拟过程中考虑了人的学习能力及人与人之间的相互作用等因素,模型加入吸引子使模拟人的疏散行为更为灵活。基于人能通过熟悉周围环境作出合理判断的学习能力,引入了"积累步长"的概念,使人的沟通判断能力(走过的路径、边界和出口位置通过交流能够获取)在模型中得到体现。获取足够信息的人可以避免多余的寻找,降低了逃生时间,体现了"人多力量大"的互助行为。通过大量的模拟实验,并讨论不同的环境条件对人群疏散的影响。     

Evolution of male mating behavior: male spadefoot toads preferentially associate with conspecific males

The evolution of male breeding aggregations is difficult to explain because males may reduce their reproductive success by associating with their closest competitors. We examined aggregative behavior by male New Mexico spadefoot toads, Spea multiplicata, which form breeding choruses in rain-filled pools. We specifically asked whether males are attracted to conspecific calls and, if so, whether they preferentially associate with those male calls that are also attractive to females. Field observations revealed that males showed significant clustering with conspecifics within breeding ponds, whereas laboratory phonotaxis experiments revealed that males preferentially associated with conspecific male calls. Moreover, when males were presented with conspecific calls that differed in call rate, smaller males associated with the stimulus preferred by females (average call rate). Thus, males appear to evaluate the attractiveness of competitors using the same trait employed by females to assess potential mates, and males adjust their positions relative to competitors depending on their size. We discuss these results in the light of several current hypotheses on the adaptive significance of male breeding aggregations. Received: 20 December 1999 / Accepted: 18 March 2000     

Induction of host specificity in larvae of Manduca sexta: chemical dependence controlling host recognition and developmental rate

Summary. The tobacco hornworm, Manduca sexta L. (Lepidoptera: Sphingidae) is a specialist on Solanaceae. This host specificity is induced as the larva feeds on solanaceous foliage, so that solanaceous-reared larvae will refuse to feed on other plants. Experiments were designed to determine the role of dietary constituents on the induction of host specificity and the effects of these on development of M. sexta. Choice assays using leaf discs of cowpea, Vigna sinensis (Fabaceae), were used to monitor the isolation of relevant chemical cues from foliage of potato. An aqueous extract of potato foliage strongly stimulated feeding. This extract was partitioned with n-butanol under alkaline conditions to obtain a highly active butanol extract. Reversed phase flash chromatography with a water-methanol gradient gave an active fraction that was used as a supplement for wheat germ-based artificial diet. Larvae reared on this s-diet became dependent on potato allelochemicals for initiation and continuation of feeding activity. These larvae also developed faster than larvae reared on the control p-diet, but no effect on adult mass was detected. Further flash chromatography of the active fraction under alkaline conditions provided a highly active sub-fraction, and semi-preparative HPLC using gradients of water and acetonitrile resulted in the isolation of a single compound. Bioassays indicated that this compound alone can account for host recognition by solanaceous-reared larvae. The results suggest that the mechanism of induced host specificity in M. sexta involves development of dependence on this compound. Received 21 December 1999; accepted 14 March 2000