Human and policy dimensions of soundscape ecology

Soundscape ecology is an emergent and potentially transformative scientific discipline. However, the majority of research within the field has been conducted by natural scientists focused on quantifying the characteristics and dynamics of soundscapes and examining their effect on non-human biota. A more holistic approach to the science and management of soundscapes requires full integration with the social and policy sciences. To facilitate the development of this integration, we propose an integrative human and policy dimensions of soundscape ecology framework that conceptualizes the complex and dynamic relationships between humans and their acoustic environments. The framework is grounded in four distinct disciplines – health, psychology, economics and anthropology – that have used different methodologies and metrics to focus on certain aspects of human–soundscape interactions. We provide a review of previous empirical research within each of these fields. Along the way, we identify unexplored avenues of discipline-specific research that can further the field of soundscape ecology. The human and policy dimensions of soundscape ecology framework provide the logic and structure upon which an interdisciplinary body of scholarship can be built in the future. We conclude by utilizing our review and integrative framework to propose specific focused soundscape policy and management recommendations. We argue the anthropogenic dominance of soundscapes can be mitigated through more proactive, integrative and holistic soundscape policies and management practices.     

低围压循环荷载作用下饱和粗粒土的动力特性与骨干曲线模型研究

基床层是铁路路基的核心组成部分,一般为粗颗粒土,厚约2.5～3.0 m,长期直接承受行车荷载的反复作用,其在动载反复作用下的变形特性是评价路基工作性能的关键要素之一。为研究粗粒土在列车循环荷载作用下的应力-应变特性,开展了一系列应力控制的单向循环加载大型动三轴试验,模拟列车动载和路基粗粒料填筑实际情况,包括不同动应力幅值（模拟不同列车轴重）、不同围压（模拟不同埋深）的动三轴持续振动试验。结果表明,在循环荷载作用下,土体刚度变化与振动次数、围压关系密切。根据动应力幅值大小的不同,循环荷载作用下饱和粗粒土的动应变随振次的发展形态可分为3种类型：稳定型、破坏型和临界型。根据试验所得出的动应力-应变关系曲线特点,建立了含围压和循环振次的骨干曲线模型。与传统的骨干曲线模型相比,该模型能反映土体刚度随循环振次的变化,更能反映列车往复作用的实际情况;同时该模型能用于估算路基土体动强度,对铁路路基核心层的动力变形稳定性评价和基于动力变形控制的路基设计具有参考价值。     

用函数变换设计速度传感反馈地震计

短周期地震计主要用于观测地方性的微小地震,用速度传感器设计的反馈式短周期的地震计的工作参数稳定性不好,是国内外观测实践都证实了的问题。借鉴位移传感反馈地震计工作参数偏差较低的思路,介绍了通过采用函数变换方法设计速度传感反馈地震计的解决方案。用函数变换方法设计的速度传感反馈地震计,既实现了加大负反馈深度又不降低噪声指标的双重目标,有加深负反馈和由闭环反馈生成的闭环周期位于通带外的优点。即便是机械摆受到环境变化的影响或随时间推移而出现了漂移或老化,其对通带内的幅频特性的影响亦较小。由函数变换电路生成摆函数的工作周期及工作阻尼与机械摆的参数完全无关,仅取决于变换电路中的两个电阻和两个电容的精度。     

The Mechanisms of Soil Regulating Nitrogen Dynamics

In recent decades, the amount of reactive nitrogen (N) has rapidly increased. While the reactive N, mainly chemical N fertilizers, meet food and economic development demands, it has also caused many environmental problems. Now, there are the triple challenges of food security, environmental degradation and climate change for the world due to the rapid increase of reactive N. Most of reactive N has been input to soil firstly, which would export to hydrosphere, atmosphere, and biosphere after transformed as different N forms through various N transformation processes. Thus, soil N transformations play very important role in regulating the fate of soil N. In this article, we review the methods determining the rates of soil N transformations, and clarify the role of soil gross N transformations to regulating soil N dynamics and its mechanisms. Our results suggest that the coupling of soil N transformation with climate and plant species-specific N preferences play important role in optimize N use efficiencies in agricultural production. However, scientists usually just qualitatively discuss the feedbacks and its mechanisms between plants and soil N transformations, due to the limitation of research methods. The quantitative investigation on the effects of these feedbacks on soil gross N transformations is of important significances to understand the feedback and its mechanisms between plants and soil N transformations, to optimize N fertilization, and to make N pollution control countermeasures and so on.     

The method of high harmonics for determining reheating palaeotemperatures

Summary When reheated to temperatures below the Curie temperature (T_c) and subsequently cooled in a constant magnetic field it has been shown that rocks which contain magnetic minerals will acquire an induced magnetic anisotropy (IMA). The IMA is capable of retaining information on the palaeointensity of the geomagnetic field and the palaeotemperature of this most recent heating. A novel technique for determining the palaeotemperature has been developed, employing the high-harmonics method.     

暴雨中积云对流的反馈机制

本文在分析梅雨期暴雨中尺度水热场特征的基础上,利用Nitta的云谱模式和积云对流参数化方法对暴雨区积云对流对环境水热场的反馈机制进行了诊断研究.结果表明,在暴雨过程中,主要是高云和低云两类云的活动,在对流层中层很少有卷出的积云;积云对流的补偿下沉气流强烈地加热和干燥环境大气,这种加热和干燥效应主要被积云卷出的液态水再蒸发所抵消;同时,在暴雨过程中还可能存在某种不同于积云卷出液态水的蒸发冷却和湿润环境大气的物理机制.     

冷锋雨带中湿物理过程与非绝热锋生的相互作用

利用包含冰相微物理过程参数化方案的三维非静力中尺度／云模式（ARPS）模拟了与冷锋有关的冷锋雨带（NCFR）结构，着重分析了锋面云系发展演变的主要特征。模拟结果表明，锋面云系是由位于锋面前沿处的锋面次级环流的上升运动激发的；锋面强度与冷锋云（雨）带中的潜热释放之间的正反馈引起的持续非绝热锋生是锋面以及冷锋雨带得以长时间维持的主要物理机制。进一步分析表明，锋区两侧位温梯度的增加是与沿着冷锋表面的倾斜上升运动引起的云水及水汽的再分布密切相关的，即在冷气团中由云水蒸发发冷却形成冷池，而在暖气团中由水汽凝结以及雨滴冻结等形成暖池，这种冷／暖池在冷／暖气团上的叠加是引起非绝热锋生的关键。     

Feedback control for ecosystem management: The case of wolf-elk-hunting dynamics in the US Mountain West

The purpose of this paper is to explore the promise of utilizing some relatively new feedback control techniques in ecosystem management. First, we set forth a basic ecological-economic model of a predator-prey-hunting system in which both the predator and prey have use(flow) and non-use(stock) value and when the predator can inflict transboundary damages. We then use new data from the US Mountain West to show how a particular feedback approach—linear parameter-varying(LPV) control—can be utilized in this context. Our LPV model is able to quantify the cost of managing disturbances that inevitably arise as a manager tries to keep the actual path of the system "close" to its optimum. The results suggest management strategies in mountain ecosystems that feature large, mammalian carnivores.     

A study on using pre‐bent steel strips as seismic energy‐dissipative devices

Buckling is usually conceived as an unstable structural behavior leading to lateral instability of axially loaded members, if not properly supported. However, a pre‐bent strip would become an excellent seismic energy‐dissipative device if it is deformed in a guided direction and range. Geometrically large lateral deformation of the steel strips in buckling leads to inelastic behavior of the material and dissipates energy as a consequence. The purpose of this study is to propose a new type of seismic damper in the form of braces based on pre‐bent steel strips. The nonlinear elastic stiffness of monotonously loaded pre‐bent strips in both compression and tension is derived. The energy‐dissipative characteristics of the proposed damping device are investigated via component tests under cyclic loads. Experimental results indicate that the force–displacement relationship of pre‐bent strips in cyclic loads exhibits mechanical characteristics of displacement‐dependent dampers. A series of seismic performance tests has been conducted further to verify the feasibility and effectiveness of using the proposed device as seismic dampers. Encouraging test results have been obtained, suggesting feasibility of the proposed device for earthquake‐resistant design. Copyright © 2008 John Wiley & Sons, Ltd.     

Enhanced hysteresis of suspended sediment transport in response to upstream damming: An example of the middle Yangtze River downstream of the Three Gorges Dam

The peak in sediment transport in alluvial rivers generally lags behind the peak in discharge. It is thus not clear how the hysteresis in the sediment/discharge relationship may be impacted by damming, which can fundamentally alter the water and sediment regimes in the downstream reaches of the river. In this study, a total of 500 flood events in the Yichang–Chenglingji Reach (YCR) of the Middle Yangtze River immediately downstream of the Three Gorges Dam (TGD) are analysed to study the impacts of dam operations on the hysteresis of suspended sediment transport. Sediment rating curves, hysteresis patterns, as well as lag times, are investigated to determine the relationship between suspended sediment concentration (SSC) and flow discharge (Q) at different temporal scales, from inter-annual to individual flood events, for the pre- and post-TGD period from 1992 to 2002 and from 2003 to 2017, respectively. The results showed that the TGD operation decreased the frequency and magnitude of floods. The decrease in peak flow and increase in base flow weakened the flood contribution to the annual discharge by nearly 20%. However, the relative suspended sediment load contribution during flood events was much higher than the discharge contribution, and was little impacted by the dam. At seasonal and monthly scales, more than 80% of the suspended sediment was transported by ~65% of the water discharge in the summer and early autumn. The monthly SSC–Q relationship changed from a figure-eight to an anti-clockwise pattern after the construction of the TGD. For single flood events, the TGD operations significantly modified the downstream SSC–Q hysteresis patterns, increasing the frequency of anti-clockwise loops and the lag time between peak Q and peak SSC. These adjustments were mainly caused by differences in the propagation velocities of flood and sediment waves and the sediment ‘storage–mobilization–depletion’ process, whereas the influence of lateral diversions was small. © 2020 John Wiley & Sons, Ltd.