Antibiotic resistance in potentially bacteriocinogenic probiotic bacteria in aquaculture environments

Bacteriocin‐producing bacteria in aquaculture may prevent spreading of potentially pathogenic microorganisms, and could be used as an alternative to the empirical use of antimicrobial drugs, especially for prophylaxis. Bacteriocinogenic bacteria inoculated as probiotics should not carry undesirable traits, such as antibiotic resistance. This study aimed to find potentially bacteriocinogenic bacteria in an aquaculture system and evaluate their antimicrobial susceptibility patterns. Selective cultures for enterobacteria, non‐fermenting Gram‐negative rods and Gram‐positive cocci were obtained from water samples before bacterial isolation and biochemical identification. Overall, 160 representative strains were recovered and for 57 antagonism was observed against selected strains such as Staphylococcus aureus, with antagonism being expressed better on Brain Heart Infusion medium. After exclusion of interfering factors, bacteriocin or bacteriocin‐like substances were suggested to be related to the antagonism observed. Higher drug‐resistant rates were observed among potentially bacteriocinogenic bacteria for different antimicrobials of clinical relevance. Although antibiotic resistance is a global health problem and bacteriocins are attractive alternatives to classical antibiotic even to multiresistant bacteria, the data obtained suggest that bacteriocin‐producing bacteria may harbour resistance genes available for transference in different environments. From the ecological and biotechnological perspective, antimicrobial susceptibility tests must be always performed when prospecting potentially bacteriocinogenic bacteria as probiotic candidates in the environment.     

湿帘风机降温系统安装高度对降温效果的影响

针对夏季温室内气温的垂直梯度大于10℃的问题,进行了湿帘风机安装高度对降温效果影响的对比试验。试验结果表明:对于冠层高度不超过2m的低矮作物,普通安装高度(湿帘高0.9m、风机高0.5m左右)时,中、下层温度分别在30℃和28℃左右,可以满足作物生长发育的温度要求;但对于番茄等植株高大的作物,其冠层常达到温室上层的高温区(34~35℃),适当提高安装位置(湿帘高2m、风机高1m左右),使得风机的流速场高于植株冠层顶部0.5m左右,使作物冠层的空气温度只有29~31℃,气温的垂直梯度只有4℃左右。     

The effect of exposure to nature on children’s psychological well-being: A systematic review of the literature

Over the last few decades, children have spent significantly less time actively engaged in nature-based outdoor activities compared to previous generations. This has corresponded with them increasingly suffering from a range of psychological problems. Studies have been undertaken to explore the notion that such problems can be mitigated to some extent through exposure to nature within the context of built environmental settings. While much of the literature in this area has focused on adult populations, this article provides a comprehensive review of recent studies addressing this topic targeting children aged 6–12 years old. From an initial search of the literature, a total of 1036 records were identified from which 40 studies addressing this topic were identified and analyzed. Our results show that most of these studies employed cross-sectional rather than longitudinal designs, and most identified positive psychological outcomes associated with children’s exposure to nature, with many yielding statistically significant yet weak to moderate outcomes. We further categorized studies into experimental or observational according to the research design. Observational studies primarily investigated the impact of the accessibility/quantity of natural environments within residential settings. Some experimental-based studies explored children’s active involvement in nature-based activities. In contrast, others investigated passive exposure to nature through views or visual stimuli used as surrogates of actual environments, many of which were conducted in school and public open-space settings. Most of the studies explored terrestrial, or green spaces, within the context of predominately built environments, with water-based settings (blue spaces) being underrepresented. Some differences in research focus and design were evident across different countries where the studies were undertaken. We conclude that further research is needed to unveil the associations between nature exposure and children’s psychological well-being to provide directions for future environmental design strategies, environmental education and policymaking.     

乡村振兴背景下农村人居环境治理的对策研究——以黑龙江省为例

农村人居环境治理是乡村振兴的重要组成部分，发展乡村产业，提高农村经济自身的“造血”能力，是农村人居环境治理的关键。本文立足黑龙江农村资源配置特点，发展乡村菜园经济，强调农民主体地位，构建农村人居环境治理新模式，规范、美化、绿化乡村庭院，在庭院经济中引入秸秆生物处理技术，推广双坑交替式旱厕，完善配套政策及法律支撑，保障寒地农村环境治理顺利推行，共同实现经济、社会和生态效益共赢，建设与小康社会相适应的生态宜居的美丽乡村。     

稻鸭共作对不同栽培环境稻季CH4和N2O排放的影响

稻田是大气温室气体甲烷(CH₄)和氧化亚氮(N₂O)的重要排放源, 稻田温室气体减排一直是生态农业研究的热点。目前, 采用水稻品种选择利用、水分控制管理、肥料运筹管理、耕作制度调整以及种养结合模式等方法来减少稻田温室气体排放有较好实践效应, 但不同稻田栽培环境(露地、网室)基础上的稻鸭共作对麦秸全量还田的稻田温室气体排放特征及相关土壤理化特性关联性的影响尚为少见。本研究采用裂区设计, 在两种栽培环境条件下, 以无鸭子放养的常规稻作和麦秸不还田为对照, 在等养分条件下分析麦秸全量还田与稻鸭共作模式对稻田土壤氧化还原电位、CH₄排放量、产CH₄潜力及CH₄氧化能力、N₂O排放量及N₂O排放高峰期土壤反硝化酶活性、全球增温潜势、水稻产量的影响, 为稻田可持续生产和温室气体减排提供参考。结果表明, 麦秆还田增加了稻田产CH₄潜力、提高了CH₄排放量, 降低了稻田土壤反硝化酶活性、土壤氧化还原电位和N₂O排放量, 整体上导致全球增温潜势上升96.89%~123.02%; 稻鸭共作模式, 由于鸭子的不间断活动提高了稻田土壤氧化还原电位, 降低了稻田产CH₄潜力, 增强了稻田CH₄氧化能力, 从而降低稻田CH₄排放量, N₂O排放量虽有提高, 整体上稻鸭共作模式的全球增温潜势较无鸭常规稻田下降8.72%~14.18%; 网室栽培模式显著提高了稻田土壤氧化还原电位, 降低稻田产CH₄潜力、CH₄氧化能力和土壤反硝化酶活性, 减少了稻田CH₄和N₂O排放量, 全球增温潜势降低6.35%~13.14%。本试验条件下, 稻田土壤的CH₄氧化能力是产CH₄潜力的2.21~3.81倍; 相同环境条件下, 稻鸭共作和麦秸还田均能增加水稻实际产量, 网室栽培的所有处理较相应的露地栽培减少了水稻实际产量1.19%~5.48%。本试验表明, 稻鸭共作和网室栽培可减缓全球增温潜势, 稻鸭共作和麦秸还田能够增加水稻实际产量。     

加速度计质量和安装位置对木材材料常数测试值的影响分析北大核心

为考察加速计质量和安装位置对木材测试频率的影响,设计了用自由梁和悬臂梁测试一阶弯曲频率以及用自由板测试一阶扭转频率的试验方案。根据能量法和振型推导出适用于计入加速计质量和安装位置影响的弹性模量和自由梁、悬臂梁的一阶弯曲频率的修正关系式以及剪切模量和自由板一阶扭转频率的修正关系式。应用加速度计为传感器实测了西加云杉梁、板和定向刨花板(OSB)沿其长度方向的一阶弯曲频率和一阶扭转频率,验证了导出的修正关系式应用于测试材料弹性模量和剪切模量的有效性,并以加速度计质量m和试件质量M之比m/M为参数,探讨了上述导出的修正关系式的适用范围。     

Is virtual reality a valid tool for restorative environments research?

This study examines the validity of virtual reality for assessing the restorative quality of environments. In Study 1, participants (N = 23) visited a real natural and a real urban environment, after completing a task to induce mental fatigue (i.e., a Sudoku task). We found that perceived restorative characteristics, preference ratings, experienced pleasure and self-reported restoration were higher in a real natural environment compared to a real urban environment. Perceived restorative characteristics could predict pleasure and restoration for both the real natural and urban environments, as well as preference for the real natural environment. In Study 2, participants (N = 26) visited a virtual natural and a virtual urban environment, again following a mental fatigue induction. Findings showed that virtual simulations of a natural and urban environment elicit similar effects as real counterparts of these environments. Perceived restorative characteristics, preference, pleasure and restoration were higher in a virtual natural environment compared to a virtual urban environment. Additionally, perceived restorative characteristics could predict pleasure and restoration for both the virtual natural and urban environments, and preference for the virtual natural environment. We did not find significant differences in perceived restorative characteristics between the real and virtual butterfly garden. Moreover, similar restorative characteristics predicted preference, pleasure and restoration in the real butterfly garden and the virtual butterfly garden. These findings indicate that virtual reality can be a valid tool for restorative environments research.