On the subjective experience and correlates of downtime at work: A mixed‐method examination

In the current paper, we studied downtime at work. Downtime represents a unique aspect of work time, as employees have low workload and more discretion about their activities but are still paid to be at work. Despite its prevalence and potentially significant implications for productivity and well‐being, the experience of downtime has not been a focus in the literature. To study this phenomenon, we first used a qualitative method involving 15 focus groups. Results from 95 employees showed that downtime is distinct from formal breaks and withdrawal behavior and is generally a negative subjective experience. Categories of antecedents of experience and downtime activities were classified. Next, to further explore the phenomenon, and based on Study 1 and relevant literature, we proposed several hypotheses and tested them using an experience sampling method. Results from 86 employees (across 5 workdays and 689 data points) indicated that the amount of downtime was negatively related to day level job satisfaction, job performance, and subjective health. The duration of relaxation activities during downtime mitigated the negative effects of downtime on fatigue. The effects of enjoyment level of the activities, job autonomy, work engagement, and boredom proneness were also examined. Implications, limitations, and future research are discussed.     

Bioleaching of spent Ni-Cd batteries and phylogenetic analysis of an acidophilic strain in acidified sludge

Biohydrometallurgy is a novel method to recycle discarded batteries, in which sewage sludge is used as microorganisms and culture due to the presence of indigenous Thiobacilli. A two-step continuous flow leaching system consisting of an acidifying reactor and a leaching reactor was introduced to achieve the bioleaching of spent nickel-cadmium (Ni-Cd) batteries. The acid supernatant produced in the acidifying reactor by the microorganisms with ferrous ions as the substrate was conducted into the leaching reactor to dissolve electrode materials. The efficiency of a batch treatment of batteries was examined. The results showed that the complete dissolution of two AA-sized Ni-Cd batteries with 0.6 L/d acid supernatant took about 30, 20, and 35 days for Ni, Cd, and Co, respectively. But the dissolution ability of the three metals was different. Cd and Co can be leached mostly for pH below 4.0 while the complete dissolution of Ni can be achieved for pH below 2.5. Meanwhile, a strain (named Thiooxidans. WL) accounting for the reduction of pH in the acidified sludge was isolated and sequenced. It was identified to be 100% similar to Acidithiobacillus ferrooxidans strain Tf-49 based on 16S rDNA sequence analysis. The relevant phylogenetic tree constructed indicates that the strain should be classified into genus Acidithiobacillus ferrooxidans.     

腐殖质对二氧化锰引起的五氯酚转化反应的影响

研究了在二氧化锰催化引起的五氯酚的转化反应中,腐殖质前身化合物的加入对五氯酚去除率的影响,并以p-coumaricacid为代表研究了体系pH值、反应时间、二氧化锰的质量浓度以及腐殖质前生物的浓度和分子结构对去除率的影响。结果表明,反应的最佳pH值范围是4～4.70,去除率在80%左右。五氯酚在24h内去除速率较快,去除率达到75%左右;反应到168h,去除速率趋于0,去除率达到80%左右。相同条件下,无p-coumaricacid的对照体系中,对应的反应时间内去除率仅分别为20%和25%左右。五氯酚的去除率还随二氧化锰质量浓度和p-coumaricacid浓度的增加而增大。当二氧化锰的质量浓度由0增加到100g·L-1时,去除率由0增大为95%;而当p-coumaricacid的浓度由0增加到1mmol·L-1时,去除率由25%增大到100%左右。此外,不同腐殖质前身物的分子结构和浓度对去除率分别起到了提高、不明显改变和降低的作用。     

大学生诚信状况的分析及思考

诚信是公民道德建设最基本的规范之一．当然，更应当是青年学生思想道德建设的重点．当前，大学生诚信状况的主要问题是诚信道德的认知和行为存在着明显的差异，针对这种状况，采取相应措施，加强大学生诚信道德能力培养，注重诚信制度，优化诚信环境，实施对大学生诚信道德教育是当前高校的教育重点．     

常乐稀土复合肥对玉米（Zea may L.）的细胞毒性和遗传毒性效应

为了研究常乐稀土多元复合肥对主要农作物--玉米(Zea mays L.)是否产生细胞毒性和遗传毒性效应,采用不同梯度质量浓度的稀土复合肥溶液对玉米进行处理,观察其根尖生长状况,统计分析细胞死亡率、微核率、有丝分裂指数以及对细胞DNA的损伤情况.结果表明,质量浓度为10mg·L-1以下时,常乐稀土复合肥能够促进玉米根尖的生长,100mg·L-1以上时抑制根尖生长;随着试验浓度的递增,细胞死亡率、微核率、DNA损伤率逐渐上升并具有正相关性,表现出明显的剂量-效应关系,而有丝分裂指数却随着浓度的增加逐渐下降.以上结果表明,常乐稀土复合肥对玉米确有一定的细胞毒性和遗传毒性效应,其细胞毒性阈值和遗传毒性阈值皆为100mg·L-1.     

蔬菜对土壤镉铜锌富集能力的研究

调查了福建部分污染严重地区不同蔬菜对镉、锌、铜的富集能力。结果表明蔬菜对镉的平均富集系数为0.017,锌的平均富集系数为0.116.铜的平均富集系数为0.014。蔬菜对镉的富集系数的品种间差异最大,达315倍,远高于锌和铜的富集系数的品种间差异。茭白、豇豆和莲藕对镉的富集能力较低,可作为镉污染土壤优先选种的蔬菜品种,而青包菜、白包菜、芥菜、空心菜、芋头等对镉的富集系数较高,不宜在镉污染土壤上栽培。     

Response to perceived predation threat in fiddler crabs: trust thy neighbor as thyself?

Prey require information if they are to respond to predation threat in a risk-sensitive manner. One way that individuals can obtain this information is through the predator-mediated, threat-induced behavior of conspecifics. We examined such a possibility in a refuge-seeking species, the sand fiddler crab (Uca pugilator). Crabs were either exposed directly to a simulated predation threat (a moving cylinder) or the threat-induced response of a near neighbor. We found that fiddler crabs responded to the flight of their neighbors even when they, themselves, were not privy to the stimulus that induced their neighbors response. However, the wider range of behaviors exhibited by these crabs—which included no reaction, freezing, running back to the burrow entrance, and burrow retreat—suggest that non-threatened crabs either (1) perceived the gravity of the predation threat differently from their directly threatened neighbors and/or (2) engaged in behaviors that allowed them to acquire further information in the face of uncertainty. Conspecific behaviors also had an effect on the hiding duration of crabs, with individuals hiding longer if they saw both the predation threat and the flight of their neighbor. Our results suggest that cues provided by conspecifics can play an important role in guiding the antipredator response of refuge-seeking prey.     

可循环利用污泥专用处置场建设的探讨

着重论述了国内外城市污水处理厂污泥的各种处置方法及处置现状，提出污泥土地利用是目前国内外污泥处理中的主体和重点发展的方式。根据上海市具体市情和污泥处置状况，提出在上海市建没污泥专用处置场，以解决污泥大量处置和最终用于土地利用的思路。比较详细地探讨了国外污泥专用处置场运行的现状，指出污泥专用处置场比污泥有效利用场能更大量地处置污泥且可循环反复处置，它占地面积小，在土地紧缺的上海更具利用优势。在此基础上，提出了适合上海市情的污泥专用处置场工艺流程设计、综合运行框架和具体的技术要求，以保证污泥能安全有效地处置利用，经过分析，指出在上海兴建污泥专用处置场处置污泥能获得较好的经济效益和环境效益。     

Hg2+胁迫下玉米生理生态变化的研究

通过砂培实验,研究汞胁迫下玉米的生理生态指标包括叶绿素含量、根系活力、游离脯氨酸含量的变化.结果表明,汞对玉米的胁迫是浓度和时间双重因子的作用在低汞浓度、短时间内,叶绿素含量、根系活力及游离脯氨酸含量均有上升的趋势;在高汞浓度、长时间内,各生理指标均严重下降.各生理指标对汞的敏感度略有差异游离脯氨酸含量>根系活力>叶绿素含量;其中脯氨酸含量可以作为汞污染的一个监测指标.     

广州市区大气污染特征与影响因子分析

以2000—2004年广州市国控测点的空气环境质量自动监测结果为基础数据,以我国《大气环境质量标准》的日平均质量浓度二级标准为依据计算广州市2000—2004年的各大气污染物的指数及污染负荷率,阐明广州市区主要大气污染物SO2、NO2、PM10、CO的地域分布特征、季节变化特征、年际变化特征以及由于大气中的酸性物质而形成的酸雨的变化特征并提出研究对策。结果表明:各污染物质量浓度存在明显的季节变化规律,除SO2春夏秋季污染最严重,其余几项污染程度由高到低的顺序均为冬季,春季,秋季,夏季。近5年来空气中的一氧化碳呈显著下降趋势,但二氧化硫、二氧化氮和可吸入颗粒物则呈显著上升趋势,综合污染指数也呈明显上升趋势;酸雨频率呈不显著上升且夏秋季污染大于春冬两季。广州市大气污染分布规律与风向频率以北和东北偏北方向较大,东和东南方向次之的分布基本一致。