Results 41 to 50 of about 20,721 (119)

Changing trends in prenatal screening and treatment of cytomegalovirus infection in France: 7‐year national cohort study (2017–2023)

open access: yesUltrasound in Obstetrics &Gynecology, Volume 67, Issue 6, Page 756-763, June 2026.
ABSTRACT Objectives Cytomegalovirus (CMV) is the leading cause of congenital infectious neurosensory impairment. We aimed to present national epidemiological data on maternal CMV infection during pregnancy in France, focusing in particular on primary infection in the periconceptional period or first trimester, and to assess the impact of changes in ...
P. Coste‐Mazeau   +176 more
wiley   +1 more source

直流开断中MOV均衡特性选配方法研究

open access: yesGaoya dianqi, 2023
金属氧化物压敏电阻(metal oxide varistor,MOV)广泛应用于各种直流断路器中,用于抑制过电压、系统能量耗散与开断电压建立。受目前加工工艺限制,单MOV阀片通流能力有限,故断路器中多采用多柱并联结构。柱间电流分配不均会导致局部阀片超负荷耗能,造成开断失败甚至设备损坏。文中基于实验测量建立了一种直流开断工况下的MOV电气模型,基于该模型提出了MOV阀片均流选配方法。经实验验证,传统基于雷电冲击测试方法选配的MOV在直流开断工况的均流特性不能完全满足要求 ...
龙辰   +7 more
doaj  

Root exudates mediate microorganisms to improve rhizosphere nutrient availability and crop productivity under straw mulching and slow‐release nitrogen fertilizer

open access: yesFunctional Ecology, Volume 40, Issue 6, Page 1725-1739, June 2026.
Read the free Plain Language Summary for this article on the Journal blog. Abstract Root exudates play a key role as signals and nutrients in mediating plant–microbe communication. However, critical knowledge gaps remain regarding how root exudates mediate soil–microbe–plant interactions to regulate crop yield under long‐term straw mulching combined ...
Jiajie Song   +7 more
wiley   +1 more source

贵州山岖水流失影响因素综合评价研究

open access: yesShuitu Baochi Xuebao, 1994
该研究以流域为单元,选定17个中等流域,研究各流域地质,地貌、土壤、森林覆盖率、植被覆盖率、降雨量、旱坡耕地垦殖率、土壤垦殖率、人均占有粮食、人均纯收入、人口文化素质,人均乡镇企业产值、人均农业产值以及人均国民生产总值等多因素与河流输沙量的关系,建立了各单因素及复因素与输沙关系的数学模型,研究结果表明,影响河流输沙最显著的因素为旱坡耕地垦殖率,森林覆盖率和人口密度,其次为人均占有粮食和土壤类型 ...
朱安国 林昌虎
doaj  

典型黑土小流域侵蚀强度时空变化特征——以海伦市光荣小流域为例

open access: yesShuitu Baochi Xuebao, 2023
为了系统反映黑土区典型水蚀小流域土壤侵蚀特征,基于连续的Landsat TM/OLI影像计算NDVI,并基于优化后的土壤和土地利用参数,结合实地调查,利用中国土壤流失方程(CSLE)、基于单位流量加权侵蚀沉积模型(USPED)分别模拟了海伦市光荣小流域2000-2021年间平均土壤侵蚀模数和侵蚀沉积分布格局,并通过融雪侵蚀模型(SHI)模拟了2017年春季融雪侵蚀空间分布,综合分析了小流域的侵蚀格局成因。结果表明:2000-2021年间CSLE模拟发现,小流域平均土壤侵蚀模数为5.57 t/(hm2·a)
汪浩   +8 more
doaj  

Rapid construction of insect–plant interaction networks via multiplexed long‐fragment DNA metabarcoding and NGS

open access: yesMethods in Ecology and Evolution, Volume 17, Issue 6, Page 1896-1909, June 2026.
Abstract Molecular identification of insect food webs can accurately reveal complex trophic interactions and serve as a foundation for understanding ecosystem functioning and advancing biodiversity conservation. This process typically involves DNA library construction, high‐throughput sequencing and subsequent steps, including data assembly, annotation,
Xiao‐man Zhang   +9 more
wiley   +1 more source

滇池流域农田径流磷素流失的土壤影响因子

open access: yesShuitu Baochi Xuebao, 2011
试验采用田间原位模拟降雨并结合多元线性回归(逐步)的统计分析方法,分别在滇池流域的6个点位研究旱季和雨季农田土壤的理化性质与径流中磷素流失的关系。结果表明:在旱季和雨季进行的田间原位模拟降雨的平均产流起始时间、产流历时、产流量和平均出水速度均无显著的差异。旱季径流的产流强度曲线比雨季波动大;2次试验中,质地为砂质粘壤土的大渔乡元宝村(C-2)点的初始产流强度和平均产流强度均最大。土壤孔隙度与降雨平均入渗率呈显著正相关关系(R=0.332*,n=12);0-5 cm的土壤速效磷(Olsen-P ...
张燕, 李永梅, 张怀志, 张维理
doaj  

Calibration of the species threat abatement and restoration metric's threat abatement component in a Costa Rican landscape

open access: yesConservation Biology, Volume 40, Issue 3, June 2026.
Abstract Achieving global conservation policy goals requires the ability to set and measure progress toward science‐based targets for biodiversity. The species threat abatement and restoration (STAR) metric was developed to enable actors to set science‐based targets for species.
Louise Mair   +17 more
wiley   +1 more source

坡耕地地表起伏对坡面漫流的影响

open access: yesShuitu Baochi Xuebao, 2020
为揭示微尺度条件下地表起伏对坡面漫流的影响,通过野外人工模拟降雨试验,在相同降雨历时下,分析了60,90,120 mm/h雨强下单凸起、单凹陷2种单式起伏和凹凸相连、凹凸相间2种复式起伏以及对照组5种微地形对坡面漫流的影响。结果表明:(1)3种雨强下,与光滑组相比,凸起、凹陷以及凹凸组合均会延迟地表初始产流时间,具体表现为对照组 < 凸起组 < 凹陷组 < 凹凸相间组 < 凹凸相连组的趋势;(2)凸起和凹陷的存在均会减小坡面漫流的平均流速,其中凹凸相连坡面平均流速最小;(3)3种雨强下 ...
李志刚   +4 more
doaj  

大粗糙单元对坡面流水动力学特性的影响

open access: yesShuitu Baochi Xuebao, 2018
通过室内定床冲刷试验,选用砂布床面模拟土壤下垫面,选用砂布+塑料半球体(直径为40 mm)床面模拟大粗糙单元下垫面,在较大流量(2.81~84.43 L/min)、坡度(2°~10°)范围内,系统研究了大粗糙单元对坡面流水动力学特性的影响。结果表明:(1)大粗糙单元床面的平均流速、平均水深和弗劳德数与流量之间均呈幂函数正相关关系;平均流速和弗劳德数与坡度之间均呈幂函数正相关关系,而平均水深与坡度之间呈幂函数负相关关系;阻力系数随雷诺数的增大而逐渐减小。(2)大粗糙单元增加了坡面流阻力,延缓了坡面流流速 ...
柳晓娜   +6 more
doaj  

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