Results 41 to 50 of about 10,026 (174)
Assessing the Corn Belt as an anthropogenic barrier to migrating landbirds in the United States
Conservation Biology, Volume 39, Issue 5, October 2025.Abstract Migrating landbirds adjust their flight and stopover behaviors to efficiently cross inhospitable geographies, such as the Gulf of Mexico and the Sahara Desert. In addition to these natural barriers, birds may increasingly encounter anthropogenic barriers created by large‐scale changes in land use. One such barrier could be the Corn Belt in the
Fengyi Guo +7 more
wiley +1 more source
Preliminary study on the pollution characteristics of atmospheric particles over the offshore marine atmosphere [PDF]
, 2015 近岸海域是大气污染物从陆地向海洋迁移、扩散的过渡带，也是陆海相互作用的主要通道，各类污染物经过大气的长距离输送到达海洋上空，通过干湿沉降进入海洋，直接影响着海洋生态环境。海洋生态系统的变化也将对海洋和大气的相互作用产生反馈。近年来，近岸海洋大气复合型污染问题日益突出，细粒子颗粒物污染导致的能见度降低及其相关联的灰霾污染天气日益增多已成为海洋大气环境研究中亟待解决的一个重要问题。针对日益严重的大气污染，本项研究通过离线分析技术和实时在线分析等方法对近岸海域大气颗粒物中持久性有机污染物多氯联苯（PCBs ...
赵淑惠
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On the normative roles of biodiversity and naturalness in conservation
Conservation Biology, Volume 39, Issue 5, October 2025.Abstract Nature is an opaque concept. Consequently, the term biodiversity conservation has replaced nature conservation in most conservation contexts. We review the conceptual indeterminacies that plague the terms nature and natural but then show that comparable difficulties plague biodiversity.
David Saltz, Shlomo Cohen
wiley +1 more source
Spatial and temporal variations of nutrients in the upper South China Sea: physical-biogeochemical modulations and their comparisons with the Gulf of Mexico and Caribbean Sea [PDF]
, 2016 氮（N）、磷（P）、硅（Si）等营养元素是海洋初级生产和食物链的物质基础，在很大程度上决定了上层海洋的生产力水平，并影响海洋生物泵的固碳效率。海水中营养盐的分布和通量受多种物理动力以及生物地球化学过程的调控，研究这些控制过程和机制是海洋学的经典命题，其核心问题在于：营养盐的时空格局如何？控制其时空格局的关键过程有哪些？如何定量这些过程？本论文以南海作为主要研究区域，探讨其中营养元素的时空分布格局及关键控制过程，并应用物理-生物地球化学耦合手段进行定量解析；同时开展南海与墨西哥湾-加勒比海 ...
杜川军
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Risk, Hazards &Crisis in Public Policy, Volume 16, Issue 3, September 2025.Abstract Norway's oil sector faces significant security challenges due to rapid technological advancements and heightened geopolitical tensions, particularly concerning threats from Russian drones. The sector maintains a vigilant approach, continually monitoring and adapting to evolving threats.
Riana Steen, Tommy B. Hansen
wiley +1 more source
Study on A Novel Frequency Tunable Piezoelectric Vibration Energy Harvesting Device [PDF]
, 2015 随着传感器技术、嵌入式计算机技术、无线通信技术的快速发展，无线传感器网络（WSN）得到了广泛应用。传统电源已无法满足无线传感器网络应用的要求，因此俘获环境能量并将其转换为电能为无线传感器供电成为传统电源的一种替代方案。环境中的振动能凭借能量来源广泛、收集方便的特点而成为了很具吸引力的环境能量源。振动能量的回收方式主要有三种，即电磁式、静电式和压电式。其中压电俘能方式可以直接将施加的应变能转化成电能，适用于各种尺度，结构相对简单，无需额外的电源，而且易于集成 ...
李营泰
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Risk, Hazards &Crisis in Public Policy, Volume 16, Issue 3, September 2025.ABSTRACT This article explores the sociohistorical construction of civilian unpreparedness as a public policy issue in Los Angeles, arguing that it emerged not as a neutral response to escalating urban risks, but as a mechanism through which actors negotiated power dynamics amid urban transformations between 1940 and 1980.
Piero Tellerías Melgarejo
wiley +1 more source
Ultrasound in Obstetrics &Gynecology, Volume 66, Issue 2, Page 200-209, August 2025.Abstract Objectives Neonates with critical congenital heart disease (CCHD) are at risk for adverse early brain development and long‐term neurodevelopmental sequelae. Insulin‐like growth factor‐1 (IGF‐1) and insulin‐like growth factor binding protein‐3 (IGFBP‐3) are essential contributors to brain growth and maturation.
M. Nijman +33 more
wiley +1 more source
Jianzhu Gangjiegou Jinzhan, 2020 以某两栋办公单体间的长悬臂钢连廊为原型,考虑沿钢连廊长度方向的脉动风速非完全相关性,采用谐波叠加法模拟风速时程,并基于准定常假定进行钢连廊的风振时域分析,得到了结构的风振响应和杆件内力。研究表明:由于该钢连廊的特殊体型,在考虑脉动风速水平向空间相关性后,悬挑端的加速度响应增大明显,并产生了扭转振动;钢连廊的风振系数,尤其是长悬挑部分的风振系数增大效应明显;部分构件的内力增幅明显。因此,在长悬臂钢连廊设计中应考虑风速水平空间相关性对风致效应的影响。
夏亮 +4 more
doaj
, 2016 沙波运移预测是海洋开发必不可少的一环。通常采用非线性谱分析方法分析沙波实测资料从而预测沙波运移。然而这种方法仅是从统计的角度进行预测,它不包含水动力、加载风速、沙质底床性质等关键因素对沙波运移的影响。对此本文提出了一种谱分析模型解决此类问题。该模型基于沙波形状不变假设,引入波谱能量平均运移速度,考虑了台风产生的风浪和涌浪,利用波浪输沙理论计算台风期间的沙波运移,厘清了一般波流作用和台风作用引起的沙波位移。模型计算结果与实测数据吻合,可以用来预测10 ...
曹高辉, 林缅, 江文滨
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