大气CO2浓度升高和氮肥施用对三江平原湿地小叶章生物量及根冠比的影响

利用开顶箱薰气室（open—top chamber）试验装置,研究了不施氮（NN）、施常氮（MN,5g·m^2）和施高氮（HN,15g·m^2）3个氮素水平下大气CO2浓度升高对小叶章（Calamagrostis angustifolia）生物量和根冠比的影响。结果表明,大气CO2浓度升高对小叶章生物量的影响因生长期而异。大气CO2浓度升高对小叶章地上生物量的促进作用主要表现在生长前期,拔节期和抽穗期地上生物量较正常大气CO2浓度增加12．42％～22．60％,而腊熟期和成熟期仅增加3．11％～12．97％;大气CO2浓度升高对小叶章地下生物量的促进作用在生长后期表现明显,除拔节期外,小叶章地下生物量增加17．63％～42．20％。小叶章生物量和根冠比对大气CO2浓度的响应与供N水平有关。在HN水平下,大气CO2浓度升高使小叶章生物量和根冠比明显增加,在NN条件下促进作用则不显著。小叶章根冠比明显增加主要是地下生物量显著增长引起的。     

Sibling competition in guinea pigs (<Emphasis Type="Italic">Cavia aperea</Emphasis> f. <Emphasis Type="Italic">porcellus</Emphasis>): scrambling for mother’s teats is stressful

Lactation is the most energy-intense period in the life of a female mammal. This can cause severe conflict between mother and offspring over the duration of lactation but also between siblings over the amount of milk each pup gets from its mother. Thus, competitive interactions between siblings are expected, and competition is likely to increase with litter size, particularly in species where the number of offspring exceeds the number of teats. We studied sibling competition in the domestic guinea pig (Cavia aperea f. porcellus), which has two teats, but frequently bears litters of up to five pups. By cross-fostering we created non-competition (control) litters with two pups and competition litters with four pups and observed nursing behaviour on days 5, 10, 15 and 20 postpartum. Pups of larger litters had lower growth rates, indicating increased competition among siblings in these litters. Pups of larger litters had to wait longer for access to a teat and spent less time suckling than pups of smaller litters but ate more solid food instead. Additionally, we manipulated the individual short-term need of pups by separating half of the pups of each litter for 2 h from their mothers before observation. Within a litter, hungry pups achieved access to milk faster and spent more time suckling than non-hungry pups. Pups competed mostly by scramble competition. Aggressive interactions occurred only in large litters. Pups of large litters had higher cortisol levels than pups in small litters. These effects decreased with age as pups became increasingly independent of maternal milk. Pup behaviour appears to fit better with models of scramble competition than with those of honest signalling. This contribution is part of the special issue “Sibling competition and cooperation in mammals” (guest editors: Robyn Hudson and Fritz Trillmich).     

The accumulation of geophysical data in digitized format may give glimpses into the evolution of the Earth

The increasing use of computers since the 1960s, has implied the digitization of observations in meteorology, oceanography and other observational sciences. Enough data has been accumulated to suggest that some patterns of evolution in the world may be discernable. The present article deals with what appears as changing tides around Canada.     

Consumer health risk to pesticide residues in Salvia officinalis L. and its infusions

Salvia officinalis L. is a popular herb widely used in culinary, cosmetic, and medicinal preparations, and also as an ornamental plant. Sage crops are threatened by many diseases, such as gray mold, powdery mildew, and leaf spot, by weeds, and by pests, such as aphids. Use of crop protection products may lead to presence of pesticide residues in this herb. The aim of this work was to study presence of pesticide residues in the herb, S. officinalis L., available on the retail market in Poland, to verify their compliance with the maximum residue levels (MRLs) and to assess the chronic and acute risks associated with consumption of this herb and infusions prepared from contaminated sage plants. Ninety active substances of pesticides were analyzed, including all active substances registered in Poland for protection of the sage. Five active substances were found, one fungicide – boscalid and four insecticides: chlorpyrifos, pp′-DDT, dimethoate (residue levels above MRL) and indoxacarb. The chronic and acute exposure to pesticide residues consumed with sage did not exceed 0.02% of the acceptable daily intake (ADI) and 0.1% of the acute reference dose (ARfD), respectively.     

Water-level based discrete integrated dynamic control to regulate the flow for sewer-WWTP operation

• A model-free sewer-WWTP integrated control was proposed. • A dynamic discrete control based on the water level was developed. • The approach could improve the sewer operation against flow fluctuation. • The approach could increase transport capacity and enhance pump efficiency. This study aims to propose a multi-point integrated real-time control method based on discrete dynamic water level variations, which can be realized only based on the programmable logic controller (PLC) system without using a complex mathematical model. A discretized water level control model was developed to conduct the real-time control based on data-automation. It combines the upstream pumping stations and the downstream influent pumping systems of wastewater treatment plant (WWTP). The discretized water level control method can regulate dynamic wastewater pumping flow of pumps following the dynamic water level variation in the sewer system. This control method has been successfully applied in practical integrated operations of sewer-WWTP following the sensitive flow disturbances of the sewer system. The operational results showed that the control method could provide a more stabilized regulate pumping flow for treatment process; it can also reduce the occurrence risk of combined sewer overflow (CSO) during heavy rainfall events by increasing transport capacity of pumping station and influent flow in WWTP, which takes full advantage of storage space in the sewer system.     

社会信任、合作能力与农户参与小农水供给行为——基于黄河灌区五省数据的验证

在政府主管的小农水供给模式无法完全满足农业分户经营的需要的现实背景下,农户参与供给是实现小农水供需平衡的有效方式。本文利用黄河灌区宁夏、内蒙古、陕西、河南和山东五个省份1558户微观农户数据,引入农户社会信任和合作能力因子,考虑农户农业收入水平和所处省份差异,采用多群组结构方程模型,探究农户参与小农水供给的行为。首先,运用信度和效度检验对农户参与小农水供给行为量表进行了分析。在此基础上,运用多群组结构方程模型,以农户农业收入水平和所处省份为调节变量,分析农户社会信任和合作能力对其参与小农水供给行为的影响。研究结果表明:农户的社会信任和合作能力显著正向影响农户参与小农水供给的意愿,其中农户的合作能力影响程度较大,农户的社会信任影响程度次之;农户的社会信任、合作能力和参与供给意愿对其参与小农水供给行为有显著正向影响,且影响程度最大的是农户的参与供给意愿,其次是农户的合作能力,最后为农户的社会信任;农户的社会信任对其合作能力有显著正向影响。多群组分析表明,农户的农业收入水平及其所处省份显著调节农户参与小农水的供给行为。其中,农业收入作为调节变量结果显示,农业收入高的农户参与小农水供给的意愿更强烈,参与供给行为水平更高;产生参与供给意愿后,农业收入中等偏上和中等偏下的农户更容易将意愿转化为行为。省份作为调节变量的结果显示,陕西、河南和山东农户的社会信任和合作能力对其参与小农水供给意愿的影响较大,河南和山东农户更容易将参与供给意愿转化为行为;宁夏和内蒙古农户的合作能力对其参与供给行为影响程度较大。根据以上结果,政府应根据不同地区农户的收入水平、社会信任和合作能力等实际情况,充分调动本地的社会资源,引导农户认识到参与小农水供给的重要性和迫切性,提高农户参与小农水供给的意愿和行为水平,促进小农水供需平衡的实现。     

Thermoeconomic installation limit of PV/WT hybrid energy systems for Off-grid islands

An ideal off-grid island can become 100% energy-sufficient if one installs renewable energy systems such as solar photovoltaic (PV) and wind turbine (WT) systems. However, the intermittent and uncertain nature of the power supply from renewable energy systems hinders a 100% autonomy level (AL) without an infinite energy storage capacity. The thermoeconomic installation limit (TEIL) of a PV/WT hybrid energy system was studied using hourly weather data and the energy demand profile for off-grid islands. An appropriate battery size for the TEIL was also determined. Given the current installation cost of the hybrid energy system and the battery unit, the AL for a PV/WT hybrid energy system at the TEIL is calculated to be approximately 70%. Above the limit, the size of the energy storage unit and, correspondingly, the total annual cost of the PV/WT hybrid energy system increase sharply.     

Putting time in perspective: How and why construal level buffers the relationship between wait time and aggressive tendencies

We spend a substantial part of our daily life waiting, and unfortunately, wait time can fuel aggressive tendencies. Our study examines the relationship between wait time, perceived wait time, and aggressive tendencies from a construal level perspective. In Study 1, we found that the higher the construal level, the stronger the relationship between actual and perceived wait time and the stronger relationship between perceived wait time and aggressive tendencies. In Study 2, we manipulated construal level and found that power explains the moderating impact of construal on the wait—aggressive tendencies relationships. Results demonstrate the role of construal in explaining both perceived wait time and aggressive responses to long wait times, suggesting that mental construal influences both the psychological experience of time and the subsequent reaction to that experience. Overall, these results contribute to research on subjective time perspective by enhancing the knowledge and understanding of the determinants and effects of perceived wait time.     

Towards a Tipping Point in Responding to Change: Rising Costs,Fewer Options for Arctic and Global Societies

Climate change incurs costs, but government adaptation budgets are limited. Beyond a certain point, individuals must bear the costs or adapt to new circumstances, creating political-economic tipping points that we explore in three examples. First, many Alaska Native villages are threatened by erosion, but relocation is expensive. To date, critically threatened villages have not yet been relocated, suggesting that we may already have reached a political-economic tipping point. Second, forest fires shape landscape and ecological characteristics in interior Alaska. Climate-driven changes in fire regime require increased fire-fighting resources to maintain current patterns of vegetation and land use, but these resources appear to be less and less available, indicating an approaching tipping point. Third, rapid sea level rise, for example from accelerated melting of the Greenland ice sheet, will create a choice between protection and abandonment for coastal regions throughout the world, a potential global tipping point comparable to those now faced by Arctic communities. The examples illustrate the basic idea that if costs of response increase more quickly than available resources, then society has fewer and fewer options as time passes.     

淮河流域一次梅雨锋暴雨的中尺度动力特征分析

针对2007年7月8日发生在苏皖淮河流域的暴雨,采用WRF中尺度数值模式模拟结果、FNL每日4次1°*1°再分析资料、6h地面实况观测降水资料和FY-2相当黑体亮温TBB资料对该次降水的发生、发展过程进行了分析研究。结果表明:(1)该次降水在有利的大气环流形势下,强降水发生在呈准东西向分布的梅雨锋上。位于蒙古国与我国华北—东北交界处上空的切断低压给淮河流域输入了冷空气。冷空气与西南低空急流带来的暖湿气流交汇,增强了大气斜压性;(2)正的非热成风涡度的发展促进了高层相对于低层的辐散减压,有利于垂直上升运动的发展;(3)低空强急流带所形成的动力、热力和水汽条件对暴雨落区位置产生了重要影响。