Spatial Sensitivity Distribution Research Articles

Spatial sensitivity distribution assessment and Monte Carlo simulations for needle-based bioimpedance imaging during venipuncture using the finite element method.

Despite being among the most common medical procedures, needle insertions suffer from a high error rate. Impedance measurements using electrode-equipped needles offer promise for improved tissue targeting and reduced errors. Impedance visualization usually requires an extensive pre-measured impedance dataset for tissue differentiation and knowledge of the electric fields contributing to the resulting impedances. This work presents two finite element simulation approaches for both problems. The first approach describes the generation of a multitude of impedances with Monte Carlo simulations for both, homogeneous and inhomogeneous tissue to circumvent the need to rely on previously measured data. These datasets could be used for tissue discrimination. The second method describes the simulation of the spatial sensitivity distribution of an electrode layout. Two singularity analysis methods were employed to determine the bulk of the sensitivity within a finite volume, which in turn enables consistent 3D visualization. The modeled electrode layout consists of 12 electrodes radially placed around a hypodermic needle. Electrical excitation was simulated using two neighboring electrodes for current carriage and voltage pickup, which resulted in 12 distinct bipolar excitation states. Both, the impedance simulations and the respective singularity analysis methods were compared with each other. The results show that the statistical spread of impedances is highly dependent on the tissue type and its inhomogeneities. The bounded bulk of sensitivities of both methods are of similar extent and symmetry. Future models should incorporate more detailed tissue properties such as anisotropy or changing material properties due to tissue deformation to gain more accurate predictions.

Spatial sensitivity to absorption changes for various near-infrared spectroscopy methods: A compendium review

This compendium review focuses on the spatial distribution of sensitivity to localized absorption changes in optically diffuse media, particularly for measurements relevant to near-infrared spectroscopy. The three temporal domains, continuous wave, frequency domain, and time domain, each obtain different optical data types whose changes may be related to effective homogeneous changes in the absorption coefficient. Sensitivity is the relationship between a localized perturbation and the recovered effective homogeneous absorption change. Therefore, spatial sensitivity maps representing the perturbation location can be generated for the numerous optical data types in the three temporal domains. The review first presents a history of the past 30 years of work investigating this sensitivity in optically diffuse media. These works are experimental and theoretical, presenting one-, two-, and three-dimensional sensitivity maps for different Near-Infrared Spectroscopy methods, domains, and data types. Following this history, we present a compendium of sensitivity maps organized by temporal domain and then data type. This compendium provides a valuable tool to compare the spatial sensitivity of various measurement methods and parameters in one document. Methods for one to generate these maps are provided in Appendix A , including the code. This historical review and comprehensive sensitivity map compendium provides a single source researchers may use to visualize, investigate, compare, and generate sensitivity to localized absorption change maps.

Analysis of spatial-temporal patterns and driving mechanisms of land desertification in China

Desertification is a major manifestation of land degradation in China. The monitoring and assessment of land desertification in China and the analysis of its driving mechanisms are crucial to the realization of the aspiration of “net zero land degradation” proposed by the United Nations Convention to Combat Desertification (UNCCD). An improved Mediterranean Desertification and Land Use (MEDALUS) model was applied to assess the multiyear spatial distribution of land desertification sensitivity across China in 2010, 2015, and 2020. A Principal Component Analysis (PCA) was used to evaluate the internal stability of the model. In addition, a Geographical Detector method was used to examine the driving mechanisms of desertification sensitivity in China. The results showed that extremely sensitive desertification areas were primarily concentrated within the Northwest Desert and Desertification Region, northern segment of the Qinghai-Tibet Plateau desert and desertification region, and western sector of the Inner Mongolia-Daxinganling Desert and Desertification Region. In addition, the proportion of land area showing an overall reduction in sensitivity (17.07 %) exceeded that showing an increase (16.56 %). This indicates an overall diminishing trend in sensitivity to land desertification across China. Land use intensity (LUI), drought resistance (DR), erosion protection (EP), and aridity index (AI) are consistently the most important drivers. From 2015 to 2020, the LUI emerged as the principal catalyst behind the transformation of land desertification sensitivity in China. Hence, emphasizing well-planned land use is vital for ensuring harmony between land utilization and ecological capacity. This study establishes a scientific basis for China's land desertification control strategy and serves as a quantitative analysis reference for the driving mechanisms.

Depth-selective method for time-domain diffuse reflectance measurements: validation study of the dual subtraction technique.

Research on the spatial distribution of sensitivity of time-domain near infrared diffuse reflectance measurement is reported in this paper. The main objective of the investigation is to validate theoretically calculated sensitivity profiles for a measurement geometry with two detectors and two sources in which sensitivity profiles of statistical moments of distributions of time of flight of photons (DTOFs) are spatially restricted to a region underneath the detectors. For this dual subtraction method, smaller sensitivities to changes appearing in the superficial layer of the medium were observed compared to the single distance and single subtraction methods. Experimental validation of this approach is based on evaluation of changes in the statistical moments of DTOFs measured on a liquid phantom with local absorption perturbations. The spatial distributions of sensitivities, depth-related sensitivity and depth selectivities were obtained from the dual subtraction method and compared with those from single distance and single subtraction approaches. Also, the contrast to noise ratio (CNR) was calculated for the dual subtraction technique and combined with depth selectivity in order to assess the overall performance (product of CNR and depth selectivity) of the method. Spatial sensitivity profiles from phantom experiments are in a good agreement with the results of theoretical studies and feature more locally restricted sensitivity volume with the point of maximal sensitivity located deeper. The highest value of overall performance was obtained experimentally for the second statistical moment in the dual subtraction method (∼10.8) surpassing that of the single distance method (∼8.7). This confirms the advantage of dual subtraction measurement geometries in the suppression of optical signals originated in the superficial layer of the medium.

Needle-Based Electrical Impedance Imaging Technology for Needle Navigation.

Needle insertion is a common procedure in modern healthcare practices, such as blood sampling, tissue biopsy, and cancer treatment. Various guidance systems have been developed to reduce the risk of incorrect needle positioning. While ultrasound imaging is considered the gold standard, it has limitations such as a lack of spatial resolution and subjective interpretation of 2D images. As an alternative to conventional imaging techniques, we have developed a needle-based electrical impedance imaging system. The system involves the classification of different tissue types using impedance measurements taken with a modified needle and the visualization in a MATLAB Graphical User Interface (GUI) based on the spatial sensitivity distribution of the needle. The needle was equipped with 12 stainless steel wire electrodes, and the sensitive volumes were determined using Finite Element Method (FEM) simulation. A k-Nearest Neighbors (k-NN) algorithm was used to classify different types of tissue phantoms with an average success rate of 70.56% for individual tissue phantoms. The results showed that the classification of the fat tissue phantom was the most successful (60 out of 60 attempts correct), while the success rate decreased for layered tissue structures. The measurement can be controlled in the GUI, and the identified tissues around the needle are displayed in 3D. The average latency between measurement and visualization was 112.1 ms. This work demonstrates the feasibility of using needle-based electrical impedance imaging as an alternative to conventional imaging techniques. Further improvements to the hardware and the algorithm as well as usability testing are required to evaluate the effectiveness of the needle navigation system.

2000-2018年内蒙古沙区“生态-经济-社会”复合系统脆弱性演变及关键影响因素

PDF HTML阅读 XML下载 导出引用 引用提醒 2000-2018年内蒙古沙区“生态-经济-社会”复合系统脆弱性演变及关键影响因素 DOI: 10.5846/stxb202203100586 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金面上项目(41971253) Vulnerability evolution of the ecological-economic-social complex system and the key influencing factors in the sandy region of Inner Mongolia from 2000 to 2018 Author: Affiliation: Fund Project: National Natural Science Foundation of China(41971253) 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:在气候变化和人类活动共同影响下,沙区"生态-经济-社会"复合系统快速变化,为沙漠化治理及区域可持续发展带来了严峻的挑战。因此,揭示沙区"生态-经济-社会"复合系统脆弱性演变规律,辨识影响脆弱性演化的关键因素及区域差异对沙区可持续管理具有重要意义。以内蒙古自治区为研究区,利用"暴露-敏感-适应"评估模型构建沙区"生态-经济-社会"复合系统脆弱性评价指标体系,将空间主成分分析与时空地理加权回归模型相结合,探讨2000-2018年内蒙古"生态-经济-社会"复合系统脆弱性时空演变及关键因素作用机制。结果表明:(1)脆弱性及暴露度、敏感性和适应性三个维度在空间上均有较强的异质性特征,脆弱性具有整体分散、局部聚集的分布格局;暴露度的空间分布为中部高,两边低;敏感性的空间分布为西部高,东部低;适应性的高低值分布与脆弱性相反。(2)脆弱性的变化在总体上呈现大部分区域降低,局部区域升高的趋势,显著升高区域主要聚集在内蒙古南部地区。(3)影响脆弱性分布的因素在每年均有所不同,但总体上植被覆盖度、沙漠化程度、气象指数等生态指标是影响脆弱性显著变化区域的主要因素。 Abstract:Under the combined effects of climate change and human activities, the rapidly change of the ecological-economic-social complex system in sandy areas poses serious challenges to desertification control and regional sustainable development. Therefore, it is of great significance to reveal the vulnerability evolution law of the ecological-economic-social complex system in sandy region, identify the key factors affecting the vulnerability evolution for the sustainable management of sandy region. In this paper, the Inner Mongolia Autonomous Region was taken as the research area, and the VSD (Vulnerability Scoping Diagram) model was used to construct the vulnerability assessment index system for the ecological-economic-social complex system. The spatial principal component analysis and spatio-temporal geographically weighted regression model were combined to explore the spatio-temporal evolution of the vulnerability of the ecological-economic-social complex system and the influencing mechanisms of the key factors from 2000 to 2018. The results show that: (1) vulnerability, exposure, sensitivity and adaptability have strongly heterogeneous characteristics in space, and vulnerability has a distribution pattern of overall dispersion and local aggregation; the spatial distribution of exposure is high in the middle and low on both sides; the spatial distribution of sensitivity is high in the west and low in the east; the distribution of high and low values of adaptability is the opposite of vulnerability. (2) Vulnerability changes generally show a trend of decreasing in most regions and an increasing trend in some areas. The areas with vulnerability significantly increase mainly concentrated in the southern Inner Mongolia. (3) The factors that affect the distribution of vulnerability are different each year, but in general, ecological indicators such as vegetation cover, desertification degree and meteorological indices are the main factors that affect significant change in vulnerability. 参考文献 相似文献 引证文献

Underwater Surface Flow Velocity Sensor Based on Single Side Stray Field of Permanent Magnet

Flow perception, as unique for underwater creature, is also the key components for underwater robots. However, due to strictly limitation on power consumption, flow resistance, volume and weight, to achieve flow perception ability artificialy is not easy in underwater robots. Different from the existing sensors, by using the stray field of permanent magnet, a novel surface flow velocity sensor is proposed with zero excitation power consumption, nearly zero flow resistance and considerable signal output. In this paper, based on the derived formula of electromagnetic induction with stray field, the relationship between electrode output voltage, permanent magnet stray field, surface flow field boundary layer and electrode position is established, and the spatial sensitivity distribution of sensor unit to surface flow field with optimal electrode position are studied. By using flexible surface printed electrode, when the fluid flows through the magnetic field area on the electrode surface, induced voltage proportional to the velocity is generated. Finally, the flow velocity perception ability of the sensor is verified by finite element simulation and experiments, and the sensitivity coefficients of the sensor under different electrode positions are compared. The proposed sensor can be used for any underwater vehicle to realize the perception of surface flow field without damaging the streamline shape. The intrinsic sensitivity of the sensor unit is 1.6 mV/(m∙ s^-1) with the weight of 7.8 grams.

A Coupled Deterministic and Monte-Carlo Method for Modeling and Simulation of Self-Powered Neutron Detector

To improve the efficiency of numerical calculation of self-powered neutron detector (SPND) current in pressurized water reactors (PWRs), a coupling method based on high-fidelity neutronics code and an SPND direct response model is proposed. On the detector scale, a Monte-Carlo analysis toolkit, GEANT4-SPND, is developed and verified. The toolkit, which calculates the effective contribution of insulator materials to current, has been proven to be conducive to the calculation of gamma sensitivity. On the reactor scale, detectors modeled using the deterministic method provide information of the nuclear density for the depletion calculation. The particle flux information based on the energy and spatial angular distribution is regarded as the medium of coupling strategy, thus enabling an efficient simulation of SPND current for PWR problems. This work has confirmed the necessity of particle anisotropy for current calculation in real reactor environments. The numerical code and its coupling method are verified based on the experimental values of rhodium, vanadium, platinum, and hafnium SPNDs and the K1 assembly benchmark as well. Moreover, the method is used to calculate a real VVER-1000 reactor operating in China. The numerical results are in good agreement with the values measured in realistic circumstances. What is more, the spatial distribution of the neutron sensitivity of PWR is characterized.

Establishment and validation of health vulnerability and adaptation indices under extreme weather events on the basis of the 2016 flood in Anhui province, China

Climate change could intensify extreme weather events, such as flooding, which amplifies the public health threat of waterborne diseases. Thus, assessing health vulnerability and adaptation (V&A) could facilitate nationally effective responses to extreme climate events. However, related studies are still negligible, and the assessment urgently needs to be validated with actual health data after extreme weather events. We established health V&A indices through literature review and factor analyses. Then, we separately mapped the spatial distribution of flood exposure, social and public health sensitivity, and adaptive capacity before the 2016 flood in Anhui province and compared it with post-flood diarrhea risks by using the geographic information system method to assess health vulnerability. Finally, we validated the indices by exploring the relationship between health V&A indices and post-flood diarrhea risks by using the quantile regression model. Results revealed that health V&A can be framed and categorized as key components of exposure, sensitivity, and adaptive capacity. The remarkable differences in the spatial distribution of health vulnerability were generally consistent with the demographic sensitivity, geographic flooding exposure, and post-flood diarrhea risks in Anhui. In addition, health V&A indices exerted significant positive impacts on infectious diarrhea post-flooding at all quantiles and were significant across different percentiles. Moreover, the impacts of flood exposure on total infectious diarrhea were high and continuous, whereas the impacts of sensitivity were not obvious in the flood's early stage (Coeff = 0.643; p < 0.001) but high in the flood's middle (Coeff = 0.997; p < 0.001) and late stages (Coeff = 0.975; p < 0.001). However, the impacts of adaptive capacity were heterogeneous and high in the flood's early stage (Coeff = 0.665; p < 0.001 at the 25th percentile) and late stage (Coeff = 1.296; p < 0.001 at the 75th percentile) but were insignificant at the 50th percentile. This study contributed validated three-layered health V&A indices with 30 indicators and identified that the impacts of the key components on post-flood waterborne-disease risks are heterogeneous. For instance, local public health sensitivity and adaptive capacity are insufficient to reduce these risks in the long run. This study could be used to project population health risks after extreme weather events and thereby contributes to local government planning of health adaptation.

Simulation-based sensitivity analysis and optimization of narrow strip electrostatic sensor

Aiming at the problems of low sensitivity and large interference to the dust flow field when the rod electrostatic sensor detects pipe dust, the narrow strip electrostatic sensor is proposed in this paper. Firstly, the high fidelity 3D finite element model of narrow strip electrostatic sensor, pipe and dust particles is established by COMSOL software. By gridding the model, the electrostatic field distribution in the pipeline under the action of charged dust is simulated. Then the spatial sensitivity distribution of the narrow strip electrostatic sensor in the dust pipe is analyzed. Finally, the influence of the length, width and thickness of the strip electrostatic sensor on the spatial sensitivity of the narrow strip electrostatic sensor is analyzed, which provides a basis for the structural design of the high sensitivity narrow strip electrostatic sensor.

Measurement Model and Dynamic Performance Analysis of Inlet Electrostatic Sensor on Aircraft Engine

Online electrostatic monitoring technology, which is equipped with foreknowledge information for aircraft engine faults, can effectively enhance flight safety and reduce costs. This paper provides a theoretical foundation for inlet electrostatic sensor design, which is the key issue of this technology. First, the induced principle of inlet electrostatic sensor is analyzed. Then, factors affecting spatial sensitivity distribution are quantitatively analyzed to obtain the sensitivity distribution frequency spectrum and dynamic response performance. This sensor is equivalent to a low-pass spatial filter. Results show that bandwidth changes depending on particle speed, radial position, and axial length. The optimal ring size is designed accordingly, considering sensor sensitivity, uniformity, mechanical processing, and installation.

Assessing the ecological risk to deep-sea megafaunal assemblages from seafloor massive sulfide mining using a functional traits sensitivity approach

The deep sea is subject to multiple anthropogenic disturbances, to which may soon be added mining of hydrothermally-formed seafloor massive sulfides (SMS). As a first step towards a full Ecological Risk Assessment (ERA) for SMS mining, ecological sensitivity to mining activities was assessed based on the functional traits of benthic megafaunal taxa. Faunal distribution and abundance data at two different spatial scales (within seamount and within site) were used from two video surveys conducted at un-fished SMS deposit-hosting seamounts on the Kermadec Volcanic Arc, New Zealand. For each of the 157 taxa identified in the seamount and site surveys, sensitivity was scored for six functional traits: adult size, environmental position, living habit, feeding habit, mobility, and structural fragility. Sensitivity (very low, low, intermediate, high, very high) was scored separately for three mining disturbances: passage of mining vehicles along the seafloor, sediment plumes generated by mining activity, and mineral extraction. The effects of different abundance and diversity weightings on the results were explored and transformations chosen based on ecological rationale. Sensitivity to mining impacts was summed within samples and mapped to show the spatial distribution of sensitivity. Samples (assemblages) consisted of 173 individual 200 m transects for seamount survey data and 153 individual 15 m transects for site survey data. For both spatial scales, the sensitivity of taxa and the sensitivity summed within each sample (assemblage) was greatest to mineral extraction, followed by plume impacts, and least sensitive to vehicle impacts. The location of most very highly sensitive assemblages coincided with the occurrence of hydrothermal vent taxa or previously mapped locations for hydrothermally active habitat. Highly sensitive assemblages occurred at hydrothermally inactive sulfide structures, such as chimneys, and other locations where assemblages were dominated by fragile, sessile, suspension-feeding taxa, such as scleractinian branching corals. The approach taken here illustrates spatial patterns in sensitivity within seamounts and sites and provides an important first step towards a more comprehensive ERA. This type of assessment has the potential to inform decisions on spatial management of SMS mining activities, and the suitable placement of area-based management measures, such as protected areas.

Spatial Distribution of Soil Sensitivity to Desertification in The West Delta Lands (Egypt)

Spatial Distribution of Soil Sensitivity to Desertification in The West Delta Lands (Egypt)

Identification methods of charged particles based on aero-engine exhaust gas electrostatic sensor array.

This paper presents a study of aero-engine exhaust gas electrostatic sensor array to estimate the spatial position, charge amount and velocity of charged particle. Firstly, this study establishes a mathematical model to analyze the inducing characteristics and obtain the spatial sensitivity distribution of sensor array. Then, Tikhonov regularization and compressed sensing are used to estimate the spatial position and charge amount of particle based on the obtained sensitivity distribution; cross-correlation algorithm is used to determine particle's velocity. An oil calibration test rig is established to verify the proposed methods. Thirteen spatial positions are selected as the test points. The estimation errors of spatial positions and charge amounts are both within 5% when the particles are locating at central area. The errors are higher when the particles are closer to the wall and may exceed 10%. The estimation errors of velocities by using cross-correlation are all within 2%. An air-gun test rig is further established to simulate the high velocity condition and distinguish different kinds of particles such as metal particles and non-metal particles.

Spatiotemporal changes of land desertification sensitivity in northwest China from 2000 to 2017

Sensitivity assessment is useful for monitoring land desertification. Research into how to prevent and control desertification is also important. In the arid region of northwest China, desertification is becoming worse and is a serious problem that affects local sustainable development. Based on remote-sensing and geographic information system technology, this study establishes a “soil-terrain-hydrology-climate-vegetation” desertification sensitivity comprehensive evaluation system to reflect the spatiotemporal changes of land desertification, and proposes a spatial distance model to calculate a desertification sensitivity index. The spatiotemporal change characteristics of land desertification sensitivity in northwest China are quantitatively assessed from 2000 to 2017. Moreover, the main driving factors are analyzed using the geographical detector method. The results show the following. (1) Terrain, soil, climate, vegetation and hydrology affect and restrict each other, and constitute the background conditions of the distributions and changes of sensitivity to desertification in northwest China. (2) Desertification sensitivity generally displays a low distribution characteristic on the periphery of the area and a high one in the interior. The low-sensitivity regions are mainly in the five major mountain ranges (Altai Mountains, Tianshan Mountains, Kunlun Mountains, Altun Mountains and Qilian Mountains), while the high-sensitivity regions are mainly in regions such as the Junggar Basin, the Tarim Basin and the Inner Mongolia Plateau, as well as the Taklimakan Desert, Badain Jaran Desert and Tengger Desert. The spatial distribution of desertification sensitivity is obviously regional, and the high- and low-sensitivity regions have clear boundaries and a concentrated distribution. (3) With regard to spatiotemporal evolution, changes in desertification sensitivity since 2000 have been predominantly stable, and the overall sensitivity has displayed a slowly decreasing trend, indicating that potential desertification regions are decreasing annually and that some achievements have been made in the control of regional desertification. (4) Soil and climate play a direct role in the driving factors of desertification in northwest China, and these have been found to be the most important influential factors. Vegetation is the most active and basic factor in changing the sensitivity. In addition, topography and hydrology play a role in restricting desertification changes. Socio-economic factors are the most rapid factors affecting regional desertification sensitivity, and their impacts tend to be gradually increasing. In general, desertification has been effectively controlled in northwest China, and positive results have been achieved in such control. However, against the backdrop of intensified global climate change, increasingly prominent human activities and new normals of socio-economic development, the monitoring, assessment and control of desertification in China still have a long way to go.

汾河流域生态敏感性综合评价及时空演变特征

基于格网尺度，在定量构建景观生态风险敏感性、水土流失敏感性、生物多样性敏感性的基础上，对汾河流域综合生态敏感性进行评价，采用空间自相关分析与圈层分析方法，揭示其时空演变特征。结果表明：2000-2018年研究区重度、极度敏感区面积减少，生态环境得到改善，生态敏感性空间分异与流域地形分布具有一致性；生态敏感性具有显著的空间正相关关系，在空间上呈连片连带式分布，具有明显的聚集性特征，随着高高、低低聚集网格数量的减少，生态敏感性空间结构逐渐趋于离散化；结合圈层分布，可将西南象限9-13圈层的吕梁山区与东南象限9-13圈层的太岳山区识别为流域生态环境治理的重点区域，此类区域地形以山地丘陵为主，体现了地形因素对流域生态敏感性空间分布的影响；研究区生态敏感性变化是生态本底与人类胁迫共同作用的结果。;On the basis of quantifying landscape ecology risk sensitivity, soil erosion sensitivity, and biodiversity sensitivity in a grid scale format, this paper comprehensively evaluated the ecological sensitivity of the Fenhe River Basin. Methods such as spatial autocorrelation analysis and circle analysis were employed to display the characteristics of spatiotemporal variations in the Basin. According to the research findings, the Basin presented a reduction of severe and extremely sensitive areas and an improvement of the ecological environment from 2000 to 2018. The spatial differentiation of the ecological sensitivity was consistent with the terrain distribution of the Basin. The areas with higher comprehensive ecological sensitivity were mainly distributed in Luya Mountains Region and Yunzhong Mountains Region at the source of the Fenhe River Basin. The areas with lower ecological sensitivity were mainly distributed in Fenhe Reservoir and its surrounding areas, Taiyuan Basin in the middle reaches and Linfen Basin in the lower reaches. While the ecological sensitivity presented a significantly positive spatial correlation, showing a pattern of interconnecting areal and zonal distributions with obvious agglomeration characteristics. The low-low(LL) aggregation areas were mainly related to extreme and severe sensitive areas, while the high-high(HH) aggregation areas were mainly related to mild sensitive areas. With the decrease in the number of high-high and low-low aggregation grids, the spatial structure of the ecological sensitivity tended to be discretized. The range of distribution of circles in severe and extremely sensitive areas showed a trend of first enlargement and then narrowing, which showed that with the change of time, severe sensitive areas and extremely sensitive areas decreased and the ecological environment of the study area was improved. According to the distribution of quadrants, severe sensitive areas and extremely sensitive areas were mainly distributed in the southwest and southeast quadrants. According to the distribution of circles, Lüliang Mountains Region in the 9^th to the 13^th circles of the southwest quadrant and Taiyue Mountains Region in the 9^th to the 13^th circles of the southeast quadrant were identified as key areas for the ecological environment governance. The topography of this kind of region is mainly mountainous and hills, which reflects the influence of terrain factors on the spatial distribution of ecological sensitivity of the Basin. Variations of the ecological sensitivity in the study area are the result of the combined effect of ecological background and human stress. The natural background determines the ecological environment and human living conditions of the Basin, and human activities in turn can affect or even change the ecological environment of the Basin.

Spatial distribution of sensitivity of large-area triangular detection light screen

分体式探测光幕实现室内靶道弹丸初速测试时，探测光幕的灵敏度直接影响初速测量的精度。研究了线光源配接镜头式接收装置组成大面积三角形探测光幕的灵敏度分布，考虑光学镜头离轴效应和线光源随距离衰减现象，将探测光幕内不同位置处光照度等效到线光源处，假设光幕厚度均匀，弹长始终大于幕厚，弹丸遮挡探测光幕所形成的面积与当前区域光幕截面积之比等效为弹径与当前位置处光幕宽度之比。在4.8 m×2.4 m 三角形探测光幕上进行理论仿真与实弹试验验证，仿真分析与实弹试验结果一致，靠近镜头处灵敏度大，远离镜头处灵敏度小，且关键探测区域内模拟电压幅值标准差为0.05 V，均匀性符合测试要求。研究结果可为三角形探测光幕的工程设计提供参考。

Spontaneous sensations reveal distorted body perception in complex regional pain syndrome (CRPS)

Distortions of body representation have been reported in Complex Regional Pain Syndrome (CRPS). The perception of sensations arising without external triggers (spontaneous sensations or SPS) was assessed here as a means of investigating distortions of body representation and awareness in CRPS. To avoid confounds between CRPS symptoms and SPS, lower-limb CRPS patients were included, whereas SPS were tested on the hands. Patients and controls were required to focus on their hands and to report the spatial and qualitative characteristics of SPS arising there. We found an ipsilateral decrease in the perception of thermal, pain-related and surface/mechanical SPS, as well as in the number of SPS-sensitive areas. The latter finding was predicted by decreased body awareness as assessed through questionnaires. A bilateral decrease in the perception of paresis-like SPS was also observed. Finally, the ipsilateral spatial distribution of SPS frequency and intensity underwent a shift from the fingers towards the lower parts of the palm. CRPS is likely to distort patient’s body perception and awareness of the entire half-body ipsilateral to the affected limb, and even of both sides. Such disturbances are not manifested solely as a decrease in sensitivity, but sometimes as shifts in the spatial distribution of sensitivity.

Subseasonal midlatitude prediction skill following Quasi-Biennial Oscillation and Madden–Julian Oscillation activity

Abstract. The Madden–Julian Oscillation (MJO) is known to force extratropical weather days to weeks following an MJO event through excitation of stationary Rossby waves, also referred to as tropical–extratropical teleconnections. Prior research has demonstrated that this tropically forced midlatitude response leads to increased prediction skill on subseasonal to seasonal (S2S) timescales. Furthermore, the Quasi-Biennial Oscillation (QBO) has been shown to possibly alter these teleconnections through modulation of the MJO itself and the atmospheric basic state upon which the Rossby waves propagate. This implies that the MJO–QBO relationship may affect midlatitude circulation prediction skill on S2S timescales. In this study, we quantify midlatitude circulation sensitivity and prediction skill following active MJOs and QBOs across the Northern Hemisphere on S2S timescales through an examination of the 500 hPa geopotential height field. First, a comparison of the spatial distribution of Northern Hemisphere sensitivity to the MJO during different QBO phases is performed for European Centre for Medium-Range Weather Forecasts (ECMWF) ERA-Interim reanalysis and ECMWF and the National Centers for Environmental Prediction (NCEP) hindcasts. Secondly, differences in prediction skill in ECMWF and NCEP hindcasts are quantified following MJO–QBO activity. In both hindcast systems, we find that regions across the Pacific, North America, and the Atlantic demonstrate an enhanced MJO impact on prediction skill during strong QBO periods with lead times of 1–4 weeks compared to MJO events during neutral QBO periods.

Primary accelerometer calibration by scanning laser Doppler vibrometry

A primary calibration system for vibration transducers based on laser Doppler vibrometry was complemented by a commercial scan unit. The data acquisition and analysis were optimized for accuracy and a novel procedure to visualize and compensate parasitic rigid-body motion was developed. Additionally, effects related to drift during the calibration process were explicitly taken into account and compensated, thereby allowing an automated measurement of spatial sensitivity distributions at hundreds of measurement positions with the same accuracy as a single-point primary calibration. The system was applied to study the influence of rocking and deforming motion on the apparent sensitivity of back-to-back vibration transducers during the calibration process. New insights were gained by interpreting the measured spatial sensitivity distributions as operational deflection shapes.