Common cranesGrus grus and habitat management in holm oak dehesas of Spain

Changes in agricultural policies have favored tree clearing and removal of shrubs to favor intensive farming in the holm oakQuercus ilex dehesas of Iberia. The effect of these changes for bird species wintering in this agricultural landscape has been rarely analyzed. Here the effects are studied of farming changes in traditional holm oak dehesas on population size, social structure and time budget of common cranesGrus grus in eight traditional wintering sites in Spain. The role of acorn availability, the principal winter food of the species, in relation to management is also assessed. The number of cranes in each wintering area was not related to degree of agricultural intensification, nor to the availability of acorns. However, crane flock size decreased, and the relative occurrence of isolated family groups increased in less intensively transformed wintering areas characterized by the predominance of fallow lands. The age composition of crane flocks varied with acorn availability since more juveniles were reported in areas with relatively lower acorn availability. Time budget was also related to acorn availability, since cranes spent relatively more time preening in those wintering areas with higher availability of acorns. Globally evidence suggests the need to maintain the fallow land (posíos) to sustain the wintering populations of cranes in Iberia, since this agro-grazing system maintains most of the juvenile cranes using the western migratory route.     

强化基础, 拓展应用, 构建农业院校微生物学课程新体系

《农业微生物学》是高等农业院校生物类、植物类以及环境类专业的专业基础课。1999年以来, 国家本科教育扩招和学校建设步伐加快, 专业和学生数激增, 生源质量和社会人才需求发生急剧变化。为适应新形势下微生物相关高级人才培养的需求, 根据专业类群特色, 在强化基础教学, 拓展应用教学的基础上, 积极探索课程教学新模式、新方法, 构建课程新体系, 充分调动学生主观能动性, 提高教学质量和学生综合素质。     

Extremely low frequency electromagnetic fields (ELF-EMFs) induce in vitro angiogenesis process in human endothelial cells

Effects of extremely low frequency (ELF) electromagnetic fields (EMFs) on activation of angiogenesis were analysed using cultured umbilical human vein endothelial cells (HUVECs). The cultures were exposed to a sinusoidal EMF to intensity of 1 mT, 50 Hz for up to 12 h. EMFs increased the degree of endothelial cell proliferation and tubule formation, coupled by an acceleration in the process of wound healing. Since this process is physiologically accompanied by a large modification in the structural organization of actin and focal adhesions, we analyzed the rearrangement of some cytoskeleton elements demonstrating a major reorganization of the fibres and of the focal adhesion complexes after EMF exposure. Finally, Western blot analysis revealed a significant increase in phosphorylation as well as the overall expression of VEGF receptor 2 (KDR/Flk-1) suggesting that EMFs may modulate in vitro some endothelial functions correlated to angiogenesis through signal transduction pathways dependent on VEGF.     

1950 MHz射频电磁场对SRA01/04细胞周期和凋亡的影响

目的：研究显示射频电磁场与白内障的发生关系密切,为了评价晶状体上皮细胞在射频电磁场诱导的白内障发生中的作 用,本实验探讨了1950 MHz射频电磁场暴露对人眼晶状体上皮细胞株（SRA01/04）细胞周期与凋亡的影响。方法：将处于对数生 长期的SRA01/04 细胞暴露或假暴露于频率为1950 MHz,比吸收率（SAR）为2.79 W/kg 的射频电磁场中,每天暴露1 h,每周暴露 5 天,连续暴露4 周。暴露结束后立即收集细胞,显微镜下观察细胞形态变化,噻唑蓝（MTT）法检测细胞存活力,流式细胞仪 （FCM）检测细胞周期与凋亡。结果：与假辐照组相比,暴露组细胞形态未见明显变化;细胞存活力、细胞周期分布及细胞凋亡率亦 无显著改变（P>0.05）。结论：1950 MHz射频电磁场暴露4 周对SRA01/04 细胞的形态、活力、周期以及凋亡均无明显影响,提示在 本实验条件下1950 MHz 射频电磁场不会诱发白内障的发生。     

苏南太湖水系农业非点源氮污染及其控制对策研究

控制农业非点源对水体的污染是实现区域水质管理的必要组成部分。为此,设计了一系列水田、旱地田间试验和室内模拟实验。试验结果表明,渗漏水硝态氮污染与氮肥施用量呈正相关,同时通过统计处理获得农业非点源氮素污染负荷量,并提出了农业非点源氮素污染的几种有效的控制对策。     

农田氧化亚氮排放系数的研究

通过调研多年来国内外农田N₂O排放的研究结果,建立了农田N₂O年度排放数据库,并分析了N₂O排放与各环境因子之间的关系.相关分析表明,N₂O排放与温度及降水呈显著正相关,与土壤pH值、有机碳及氮含量无显著相关.依据政府间气候变化专门委员会对农田N₂O排放系数的定义和确定方法,用年平均气温及降水量对其进行修正.结果表明,经平均气温修正后的排放系数并不减小农田N₂O排放的估计误差,但用年降水量进行修正后能减小平均相对误差16%左右.     

Measurement and analysis of static magnetic fields that block action potentials in cultured neurons

To characterize the properties of static magnetic fields on firing of action potentials (AP) by sensory neurons in cell culture, we developed a mathematical formalism based on the expression for the magnetic field of a single circular current loop. The calculated fields fit closely the field measurements taken with a Hall effect gaussmeter. The biological effect induced by different arrays of permanent magnets depended principally on the spatial variation of the fields, quantified by the value of the gradient of the field magnitude. Magnetic arrays of different sizes (macroarray: four center-charged neodymium magnets of ?14 mm diameter; microarray: four micromagnets of the same material but of ?0.4 mm diameter) allowed comparison of fields with similar gradients but different intensities at the cell position. These two arrays had a common gradient value of ?1 mT/mm and blocked >70% of AP. Alternatively, cells placed in a field strength of ?0.2 mT and a gradient of ?0.02 mT/mm produced by the macroarray resulted in no significant reduction of firing; a microarray field of the same strength but with a higher gradient of ?1.5 mT/mm caused ?80% AP blockade. The experimental threshold gradient and the calculated threshold field intensity for blockade of action potentials by these arrays were estimated to be ?0.02 mT/mm and ?0.02 mT, respectively. In conclusion, these findings suggest that spatial variation of the magnetic field is the principal cause of AP blockade in dorsal root ganglia in vitro. © 1995 Wiley-Liss, Inc.     

Effective crop structure adjustment under climate change

Choosing effective responses to the adverse impacts of climate change is a challenging issue worldwide. Crop structure adjustment is a primary strategy to effectively respond to climate change and maximize climatic resources. However, quantitative analysis of crop structure adjustment is a difficult process. This study proposes an effective evaluation method for crop structure adjustment that combines vulnerability and contribution rate assessment. Selection of prior crop with lower vulnerability, higher climate change contribution rate, and lower agricultural technology contribution rate can effectively address the adverse impacts of climate change and maximize climatic resources at a lower cost. A case study comparing spring wheat, potato and naked oat in Wuchuan County of Inner Mongolia, China determined the feasibility and practicality of this method.     

Co-Designed Exposure Protocol in the Study of Idiopathic Environmental Intolerance Attributed to Electromagnetic Fields

The hypothesis of an electromagnetic origin of idiopathic environmental intolerance (IEI) attributed to electromagnetic fields (EMF) has been widely investigated by provocation studies, which consist of deliberately exposing people with IEI-EMF in laboratory settings to particular EMF to observe volunteers’ reactions. In the majority of these studies, reactions have been found to be independent of exposure. However, most of these studies suffer from design and methodological limitations that might bias their findings or reduce their precision. As provocation studies are best suited for isolating the effects of EMF, innovative protocols should be applied. In the ExpoComm project (PNREST Anses, EST/2017/2 RF/19), several innovations have been introduced: the involvement of people with IEI-EMF in the development of the protocol, the attenuation of the anxiogenic nature of the tests, the individualization of the protocol, the validation of the neutral or normal reactivity state before the test, and the use of a cocktail of real, rather than artificially generated, sources. The objective of involving people with IEI-EMF was to increase the relevance and acceptability of the protocol, while respecting technical constraints and scientific quality requirements. This paper describes the protocol resulting from the collaborative process. Bioelectromagnetics. 2020;41:425–437. © 2020 Bioelectromagnetics Society.