Appreciated abroad, depreciated at home. The career of a radiochemist in Norway: Ellen Gleditsch (1879-1968)

Ellen Gleditsch (1879-1968) became Norway's first authority on radioactivity and the country's second female full professor. From her many years abroad--in Marie Curie's laboratory in Paris and at Yale University in New Haven with Bertram Boltram--she became internationally acknowledged and developed an extensive personal and scientific network. In the Norwegian scientific community she was, however, less appreciated, and her appointment as a professor in 1929 caused controversy. Despite the recommendation of the expert committee, her predecessor and his allies spread the view that Gleditsch was a diligent but outdated researcher with little scientific promise-a view that apparently persists in the Norwegian chemical community today. In addition to her scientific work, Gleditsch acquired political influence by joining the International Federation of University Women in 1920; she later became the president of both the Norwegian section and the worldwide organization. She worked in particular to establish scholarships enabling women to go abroad.     

1998-2015:中国广告学研究热点、趋势及网络

研究热点反映出某一学科或领域的研究行为在特定时期的偏好，这种偏好的出现与那个“当下”的历史整体性紧密相关。本文采用文献计量学方法，选择CSSCI数据库中1998—2015年间收录的广告学论文为研究对象，在Citespace 软件辅助下绘制关键词共现图谱、时区知识演化视图。从30个高频关键词中筛选出6个高中介中心度和强突现的词汇，据此分析我国该阶段广告学科的研究热点和趋势。同时，相关学者与文献介入到以上关键词盛行的社会和历史现场，使得广告学研究活动与宏观社会历史背景发生关联。研究结果表明，由特定社会情境引发的广告业界前沿议题直接影响了学界的研究热点及偏向。而从更为广泛的意义上说，广告学研究重应用、轻理论的状况没有发生根本性转变。     

西北内陆区水量平衡要素时空分析

近几十年来,气候变化和人类活动的加剧导致西北内陆区的水资源以及相关水量平衡要素的时空分布发生了显著的变化。本文借助Google Earth Engine（GEE）遥感云计算平台,基于该平台集成的多源遥感数据集,从西北内陆区全流域和三级流域两个空间尺度,对1998—2017年近20年西北内陆地区多个水量平衡要素的年际和年内变化进行时空分析,进而揭示区域总蓄变量、降水量、土壤湿度、蒸散发、地表水等核心水量平衡要素的空间分布特征与时间演变规律。研究结果表明：①在全流域尺度,研究区整体的升温趋势导致高海拔地区冰雪消融加剧、下游低海拔平原及盆地水分补给增加,使得总蓄变量呈现“高海拔减少低海拔增加”的趋势,同时,低海拔地区的地表水面积、土壤湿度和蒸散发亦相应地表现出一定的增加趋势;②在时间尺度上,各水量平衡要素除沙漠和荒漠地区外季节分异性明显,一般在夏秋达到最大,在春冬季时最小;③在三级流域尺度,不同的子流域由于水分补给来源的不同,各水量平衡要素具有不同的协同演变关系,以冰雪补给为主的流域,各要素呈现与总蓄变量相似的变化趋势,而以降水补给为主的流域,各要素变化与降水的波动关系更为密切。总之,西北内陆区各水量平衡要素在不同的时空尺度上呈现了明显的差异性,本文可为变化环境下进一步深入理解各要素协同演变特征提供重要参考。     

1998—2017年中国典型森林生态系统潜在蒸散的变化趋势及成因

潜在蒸散（PET）是计算实际蒸散、评价区域干湿状况和合理规划水资源的关键因子。本文基于1998—2017年中国生态系统研究网络（CERN）11个森林生态系统定位研究站的逐日气象数据,分别采用Penman-Monteith和Priestley-Taylor两种方法计算各森林生态系统的潜在蒸散（PET_PM和PET_PT）,分析近20年潜在蒸散年总量的变化趋势及成因,并量化了基于邻近国家气象站观测数据计算的PET_{_CMA}偏差。两种方法均表明,近20年来7个森林生态系统的潜在蒸散呈下降趋势。风速是长白山温带针阔混交林和鹤山亚热带人工常绿阔叶林潜在蒸散变化的主导因子,而净辐射主导了其他9个森林的潜在蒸散变化。PET_{_CMA}年总量较PET_PM偏高,主要是由于国家气象站下垫面的气温、风速和净辐射均高于森林定位研究站,而相对湿度偏低。北部和东部森林邻近气象站的风速和净辐射变化趋势偏高,导致PET_{_CMA}变化趋势偏高,而其他森林邻近气象站PET_{_CMA}变化趋势偏低主要源自相对湿度变化趋势偏高和净辐射变化趋势偏低。研究可为认识中国森林生态系统潜在蒸散的变化特征及其对气候变化的响应提供参考。     

The fire ant wars. Nature and science in the pesticide controversies of the late twentieth century

This essay uses an approach borrowed from environmental history to investigate the interaction of science and nature in a late twentieth-century controversy. This debate, over the proper response to fire ants that had been imported into the American South accidentally and then spread across the region, pitted Rachel Carson and loosely federated groups of conservationists, scientists, and citizens against the U.S. Department of Agriculture. The analysis falls into three sections: an examination of the natural history of the ants; an examination of the views of the competing factions; and an examination of how those views, transformed into action, affected the natural world. Both sides saw the ants in terms of a constellation of beliefs about the relationship between nature, science, and democracy. As various ideas were put into play, they interacted with the natural history of the insects in unexpected ways--and with consequences for the cultural authority of the antagonists. Combining insights from the history of science and environmental history helps explain how scientists gain and lose cultural authority and, more fundamentally, allows for an examination of how nature can be integrated into the history of science.     

1998-2011年海河流域植被覆盖变化及气候因子驱动分析

基于1998-2011年的SPOT/NDVI数据,结合海河流域土地覆盖数据分析了海河流域植被覆盖的时空变化特征,然后利用海河流域30个气象站的气温和降水资料对海河流域植被覆盖变化的气候驱动力进行了分析。结果表明：1998-2011年海河流域NDVI呈缓慢上升趋势,植被覆盖状况总体上在改善,但是在空间存在明显差异,其中农田、森林、湿地改善最为明显,植被明显改善区域与植被高波动区分布基本一致,植被覆盖基本不变区域与植被低波动区基本一致;海河流域植被覆盖变化受气候因子驱动的面积比例为31.7%,非气候因子驱动型分布于整个流域,占整个流域面积的68.3%,其分布地区土地覆盖类型主要是农田、建设用地,表明人类活动对植被变化的影响较大。