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301.
Kevin L. Woo Maree Hunt David Harper Nicola J. Nelson Charles H. Daugherty Ben D. Bell 《Die Naturwissenschaften》2009,96(3):415-419
By investigating the mechanisms that underlie the perception of environmental cues, we may begin to understand how the sensory
system governs behavioral responses. This is the first empirical study to examine learning and visual sensitivity in a reptile
species, the tuatara (Sphenodon punctatus). We established a non-intrusive psychophysical method by employing an instrumental paradigm in order to examine discrimination
learning and the ability to distinguish different flicker frequencies in the tuatara. Seventeen tuatara were trained under
an operant conditioning task to respond to various discriminative stimuli flickering between 2.65 and 65.09 Hz. Tuatara were
able to learn the operant task and discriminate between a constant light and flicker frequency rates between 2.65 and 45.61 Hz,
but not at 65.09 Hz. We demonstrated a reliable psychophysical method where these reptiles could learn a basic operant task
and discriminate visual stimuli in the form of flicker frequency rates. The tuatara’s ability to perceive flickering light
is comparable to that of avian, mammalian, and other reptilian species. This method is thus suitable for more comprehensive
examinations of vision and additional sensory abilities in other reptiles.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
302.
为研究硝酸异辛酯在储存及运输过程中的危险特性,有效预防和减少事故的发生,按照危险货物分类测试程序,通过隔板、克南、时间压力、撞击、摩擦等试验对硝酸异辛酯的固有危险性进行了评价;利用热分析技术考察了不同温升速率、水及酸雨等条件对硝酸异辛酯的热分解特性的影响.结果表明:硝酸异辛酯在相对封闭空间内遇热量、火焰、爆炸冲击及外部的机械刺激条件下表现出轻微的燃爆危险性,但不足以将其按照爆炸品进行管理;随着温升速率的增加,硝酸异辛酯热分解起始放热温度也逐渐增大,而水和酸雨均对硝酸异辛酯的分解具有促进作用,与纯硝酸异辛酯相比,其反应起始放热温度分别降低了12.4℃和27.2℃,放热量分别增大了387.439J/g和568.076J/g,失控分解危险性大大增加. 相似文献
303.
我国养猪业废弃物中四环素类、磺胺类抗生素及相关抗性基因污染研究进展 总被引:2,自引:0,他引:2
我国是世界养猪第一大国,生猪饲养量和猪肉产量均位居世界第一。养猪业每年所产生的粪便、废水中含有大量畜用抗生素及其代谢产物,使养猪业废弃物成为环境中重要的抗生素污染源之一,随之产生的抗性基因污染及传播问题也不容忽视。本文结合近年来国内外的研究数据,对我国养猪业废弃物中四环素类、磺胺类抗生素及其相关抗性基因的检测方法、污染状况及影响抗性基因传播的因素进行了分析,并基于控制我国养猪行业抗生素及抗性基因污染的目的,提出了今后的研究重点。 相似文献
304.
We hypothesized that raters' tendency to deliberately inflate performance appraisal ratings of subordinates would be associated with rater negative affectivity (NA) and two characteristics of the performance appraisal context: documentation of subordinates' work behaviors and appraisal visibility. We further hypothesized interactions among these variables, such that high‐NA, but not low‐NA raters, would be more likely to inflate ratings under conditions of low documentation and high appraisal visibility. Moreover, we predicted that NA would be associated most strongly with rating inflation when documentation was low and appraisal visibility was high, simultaneously. Results from a sample of 148 supervisors from a variety of organizations supported these hypotheses. We discuss several practical implications of the results and suggest areas for future inquiry. Copyright © 1999 John Wiley & Sons, Ltd. 相似文献
305.
Road safety policy plans often require robust calculation of the expected number of road casualties in a certain target year. The relevance of such estimations should be measured by their power to influence and support safety policy makers. Thus, techniques to evaluate the safety developments and the estimating methods must be sound, robust, and preferably accepted by both policy makers and the scientific community. In this paper, we concentrate on choosing an appropriate model used for the calculation, rather than on statistical techniques. We calculate a casualty rate from casualty data and mobility (distance travelled) data, which is extrapolated and subsequently multiplied by an expected future distance travelled. After correction for separately assessed effects of additional safety measures, the number of casualties is estimated. We investigate a method where this is done after both mobility data and casualty data are stratified into properly chosen subsets. Projecting these different trends generally leads to a result that differs from the projection of the aggregated data. Also, stratification enables incorporation in the estimation of explaining factors or additional measures related to a specific subset of the casualties. The principles of stratified projections are illustrated by three Dutch projections which were carried out between 2006 and 2008. Also, some preliminary results of further research on stratification are given. The results imply that the rates of change in casualty rate for different traffic modes or driver age, are not necessarily equal. We propose that these specific decreasing trends are a consequence of external influencing factors. 相似文献
306.
This article describes the feasibility of researchinto the relation between values of farmers andsustainability for the Dutch Ministry of Agricultureand the Dutch Federation of Agricultural andHorticultural Organisations.Firstly, a theoretical framework describes differentlevels of motivation behind conduct and choices. Itenables exploration and analysis of individualinterviews with small groups of conventional andecological farmers. The aim is to find out what theirbasic convictions regarding nature and sustainabilityare, and to analyze the relation between theseconvictions and the actual choices they make in theirfarming practice. The research shows that for somefarmers, differences in farming practice go back to themotivation level of moral convictions about what is`good farming'. For others, the motivations for aspecific farming practice are more pragmatic or`superficial'. This knowledge can be of significancefor the process of policy making.Secondly, this research demonstrates thatinvestigation into the relation between values andbehavioral choices is possible. The analysis ofinterviews among a small group of farmers gives anidea of the importance of personal values in additionto (and sometimes of more importance than) economicconsiderations. Due to the restricted size of theresearch population, however, these conclusions are oflimited generalizability. Finally, in order to make alarger research agenda possible, the research methodology isevaluated on the basis of scientific criteria. 相似文献
307.
Ben Mepham 《Journal of Agricultural and Environmental Ethics》2000,13(1):65-78
If respect for the dignity ofnon-human creatures is to be an element of publicpolicy it needs, as a first step, to be assimilatedinto the common morality. It is suggested that suchrespect may be based on several philosophicalpremises. Limiting the discussion to sentient animals,the paper reviews three of these: the concept ofanimal telos; the application of Rawlsiancontractarianism to the case of non-human animals asmoral patients; and human attitudes to animals in thelight of virtue theory. Consideration is then given tothe extent to which, by accommodating respect for thedignity of animals within the common morality, theseprinciples might find more substantive expression inpublic policy. 相似文献
308.
Paul E. Olson John S. Fletcher 《Environmental science and pollution research international》2000,7(4):195-204
Examination of a former industrial sludge basin containing organic pollutants showed that the basin had undergone substantial
ecological recovery through natural forces following the removal of surface water in 1982. Conventional phases of ecological
recovery (plant invasion and succession) have occurred, but the structure of the biodiverse plant community (51 species and
22 families) was different from that at a recovering non-polluted disturbed site. Three plant species (Bermuda grass, mulberry,
and sunflower) believed to be early invaders of the basin still persist in large numbers indicating that these species are
well suited to cope with normal environmental stresses at this area (i.e. seasonal drought and flood) as well as organic pollutants.
There was an indication that early invaders of the site fostered disappearance of contaminants thereby creating more favorable
conditions for a broader spectrum of plants to grow. Vegetation analyses of naturally vegetated hazardous waste sites hold
promise as a screening device for identifying plant species and management practices worthy of further phytoremediation investigations. 相似文献
309.
采用微卫星分子标记技术对海南近海点带石斑鱼野生和养殖群体的遗传变异进行了研究.实验所用点带石斑鱼分别于2005年6月和9月取自海南万宁石斑鱼养殖基地和三亚近海,均为20尾,取全血以酚-氯仿抽提方法提取基因组DNA,利用微卫星引物进行PCR扩增,反应产物经8%非变性聚丙烯酰胺凝胶电泳分离、银染显色,并计算了相应的遗传学参数.结果表明,在野生和养殖群体中, 7个基因座位的等位基因平均数(A)分别为3.29和3.29,每个基因座位有效等位基因数(ae)分别为1.90~3.68和1.83~4.06,野生和养殖群体平均杂合度(Ho)分别为0.790 4和0.833 7;两个群体间的遗传相似性系数为0.832 5,遗传距离为0.183 4.由此可知,点带石斑鱼野生群体的等位基因数、平均有效等位基因数等于养殖群体,而杂合度两群体相当(P=0.637>0.05),说明海南近海点带石斑鱼野生和养殖群体的种质资源较好. 相似文献
310.
针对手烧锅炉的烟尘特性,开发了一种新型湿式除尘器。运行测试结果表明,该装置能够有效地净化手烧燃煤锅炉的烟尘,避免除尘废水的二次污染。 相似文献