期刊文献+
共找到53篇文章
< 1 2 3 >
每页显示 20 50 100
2024 Wheelchair Compendium of Physical Activities:An update of activity codes and energy expenditure values 被引量:4
1
作者 Scott A.Conger Stephen D.Herrmann +3 位作者 Erik A.Willis Tom E.Nightingale Joseph R.Sherman Barbara E.Ainsworth 《Journal of Sport and Health Science》 SCIE CSCD 2024年第1期18-23,共6页
Purpose:This paper presents an update of the 2011 Wheelchair Compendium of Physical Activities designed for wheelchair users and is referred to as the 2024 Wheelchair Compendium.The Wheelchair Compendium aims to curat... Purpose:This paper presents an update of the 2011 Wheelchair Compendium of Physical Activities designed for wheelchair users and is referred to as the 2024 Wheelchair Compendium.The Wheelchair Compendium aims to curate existing knowledge of the energy expenditure for wheelchair physical activities(PAs).Methods:A systematic review of the published energy expenditure of PA for wheelchair users was completed between 2011 and May 2023.We added these data to the 2011 Wheelchair Compendium data that was compiled previously in a systematic review through 2011.Results:A total of 47 studies were included,and 124 different wheelchair PA reported energy expenditure values ranging from 0.8 metabolic equivalents for wheelchair users(filing papers,light effort)to 11.8 metabolic equivalents for wheelchair users(Nordic sit skiing).Conclusion:In introducing the updated 2024 Wheelchair Compendium,we hope to bridge the resource gap and challenge the prevailing narratives that inadvertently exclude wheelchair users from physical fitness and health PAs. 展开更多
关键词 DISABILITY EXERCISE MET Mobility
下载PDF
Older Adult Compendium of Physical Activities:Energy costs of human activities in adults aged 60 and older 被引量:6
2
作者 Erik A.Willis Stephen D.Herrmann +8 位作者 Mary Hastert Chelsea L.Kracht Tiago V.Barreira John M.Schuna Jr. Zhenghua Cai Minghui Quan Scott A.Conger Wendy J.Brown Barbara E.Ainsworth 《Journal of Sport and Health Science》 SCIE CSCD 2024年第1期13-17,F0003,共6页
Purpose:To describe the development of a Compendium for estimating the energy costs of activities in adults>60 years(OA Compendium).Methods:Physical activities(PAs)and their metabolic equivalent of task(MET)values ... Purpose:To describe the development of a Compendium for estimating the energy costs of activities in adults>60 years(OA Compendium).Methods:Physical activities(PAs)and their metabolic equivalent of task(MET)values were obtained from a systematic search of studies published in 4 sport and exercise databases(PubMed,Embase,SPORTDiscus(EBSCOhost),and Scopus)and a review of articles included in the 2011 Adult Compendium that measured PA in older adults.MET values were computed as the oxygen cost(VO_(2),mL/kg/min)during PA divided by 2.7 m L/kg/min(MET_(60+))to account for the lower resting metabolic rate in older adults.Results:We identified 68 articles and extracted energy expenditure data on 427 PAs.From these,we derived 99 unique Specific Activity codes with corresponding MET_(60+)values for older adults.We developed a website to present the OA Compendium MET_(60+)values:https://pacompendium.com.Conclusion:The OA Compendium uses data collected from adults>60 years for more accurate estimation of the energy cost of PAs in older adults.It is an accessible resource that will allow researchers,educators,and practitioners to find MET_(60+)values for older adults for use in PA research and practice. 展开更多
关键词 Energy expenditure EXERCISE MET Older adults
下载PDF
Promoting public health through the 2024 Compendium of Physical Activities:Strategies for adults,older adults,and wheelchair users
3
作者 Stephen D.Herrmann Scott A.Conger +1 位作者 Erik A.Willis Barbara E.Ainsworth 《Journal of Sport and Health Science》 SCIE CAS CSCD 2024年第6期739-742,共4页
Physical activity(PA)is fundamentally linked to public health,^(1)providing benefits including chronic disease prevention and treatment,^(2)mental health,^(3)musculoskeletal health,^(4)and healthy aging,^(5)along with... Physical activity(PA)is fundamentally linked to public health,^(1)providing benefits including chronic disease prevention and treatment,^(2)mental health,^(3)musculoskeletal health,^(4)and healthy aging,^(5)along with socioeconomic advantages.^(6)These benefits highlight the importance of promoting PA for all populations.The recent publication of the Compendium of Physical Activities(Compendium)serves as a valuable resource,^(7)offering an updated and expanded guide for adults(ages 19-59)with tailored energy cost values for diverse populations. 展开更多
关键词 ACTIVITIES PREVENTION offering
下载PDF
三维直流电阻率自然单元-无限元耦合数值模拟 被引量:1
4
作者 谢静 崔益安 +3 位作者 陈杭 罗议建 郭友军 柳建新 《地球物理学报》 SCIE EI CAS CSCD 北大核心 2023年第6期2670-2684,共15页
直流电阻率数值模拟对于实测电阻率数据反演、解释地下真实电阻率结构具有重要意义.为解决复杂地电模型剖分以及处理截断边界时面临的困难,本文提出一种新的三维自然单元-无限元耦合法.该算法在自然单元区域灵活布设自然节点以填充复杂... 直流电阻率数值模拟对于实测电阻率数据反演、解释地下真实电阻率结构具有重要意义.为解决复杂地电模型剖分以及处理截断边界时面临的困难,本文提出一种新的三维自然单元-无限元耦合法.该算法在自然单元区域灵活布设自然节点以填充复杂模型,并引入无限单元替代截断边界条件以促使刚度矩阵与电源位置无关.首先推导了稳定电流场基本方程;然后介绍了二、三维自然单元法及其形函数的构建过程;再引入三维多向映射无限单元并实现自然单元-无限元的有效耦合;最后通过4个数值模型,结合传统有限单元法、有限元-无限元耦合法以及COMSOL Multiphysics软件的计算结果,验证了算法的正确性及有效性.数值结果表明,本文所提算法满足精度要求,能有效减小计算区域,无需二次更新刚度矩阵,对复杂模型适应性强. 展开更多
关键词 直流电阻率 数值模拟 自然单元 无限单元
下载PDF
Loading direction dependence of asymmetric response of pyramidal slip in rolled AZ31 magnesium alloy 被引量:1
5
作者 Yuzhi Zhu Dewen Hou +1 位作者 Kaixuan Chen Zidong Wang 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2023年第10期3634-3641,共8页
Textured magnesium alloys usually exhibit anisotropic mechanical behavior due to the asymmetric activation of different twinning and slipping modes.This work focuses on the pyramidal slip responses of rolled AZ31 magn... Textured magnesium alloys usually exhibit anisotropic mechanical behavior due to the asymmetric activation of different twinning and slipping modes.This work focuses on the pyramidal slip responses of rolled AZ31 magnesium alloy under two loading conditions,compressive and tensile loading along the normal direction.Under the condition where the compressive loading direction is closely parallel to the c-axis of the unit cell,tensile twinning and basal slips are prohibited, dislocations then active and tend to accumulate at grain boundaries and form dislocation walls.Meanwhile,these dislocations exhibit zigzag morphologies,which result from the cross-slip from {10■1} first-order pyramidal plane to {11■2} second-order pyramidal plane,then back to {10■1} first-order pyramidal plane.Under the condition where tensile twins are prevalent,{10■1} first-order and {11■2} second-order pyramidal dislocations are favorable to be activated.Both types of dislocations behave climb-like dissociations onto the basal plane,forming zigzag dislocations. 展开更多
关键词 MAGNESIUM pyramidal slip Asymmetry CROSS-SLIP
下载PDF
Spoil characterisation using UAV-based optical remote sensing in coal mine dumps
6
作者 Sureka Thiruchittampalam Sarvesh Kumar Singh +2 位作者 Bikram Pratap Banerjee Nancy F.Glenn Simit Raval 《International Journal of Coal Science & Technology》 EI CAS CSCD 2023年第5期72-86,共15页
The structural integrity of mine dumps is crucial for mining operations to avoid adverse impacts on the triple bottom-line.Routine temporal assessments of coal mine dumps are a compliant requirement to ensure design r... The structural integrity of mine dumps is crucial for mining operations to avoid adverse impacts on the triple bottom-line.Routine temporal assessments of coal mine dumps are a compliant requirement to ensure design reconciliation as spoil off-loading continues over time.Generally,the conventional in-situ coal spoil characterisation is inefficient,laborious,hazardous,and prone to experts'observation biases.To this end,this study explores a novel approach to develop automated coal spoil characterisation using unmanned aerial vehicle(UAV)based optical remote sensing.The textural and spectral properties of the high-resolution UAV images were utilised to derive lithology and geotechnical parameters(i.e.,fabric structure and relative density/consistency)in the proposed workflow.The raw images were converted to an orthomosaic using structure from motion aided processing.Then,structural descriptors were computed per pixel to enhance feature modalities of the spoil materials.Finally,machine learning algorithms were employed with ground truth from experts as training and testing data to characterise spoil rapidly with minimal human intervention.The characterisation accuracies achieved from the proposed approach manifest a digital solution to address the limitations in the conventional characterisation approach. 展开更多
关键词 LITHOLOGY Fabric structure Consistency/relative density Dimensionality reduction Supervised learning algorithms
下载PDF
Miniaturized Electronically Steerable Parasitic Array Antenna
7
作者 Shafaq Kausar Ahmed Kausar +2 位作者 Hani Mehrpouyan Muhammad Hadi Salahuddin Tariq 《Open Journal of Antennas and Propagation》 2023年第1期1-10,共10页
In this article we propose a miniaturized dual-band electronically steerable parasitic array radiator (ESPAR) antenna. The antenna can generate up to two steerable beams. The beam-steering range of the proposed antenn... In this article we propose a miniaturized dual-band electronically steerable parasitic array radiator (ESPAR) antenna. The antenna can generate up to two steerable beams. The beam-steering range of the proposed antenna is 360˚ in the azimuth plane. The antenna’s eual-band coverage includes the frequency ranges from 2.3 GHz to 2.53 GHz and from 2.9 GHz to 3.7 GHz. The antenna consists of six folded parasitic monopole elements surrounding an active conical element. The folded monopole element design offers three times lower antenna height than that of the conventional ESPAR antennas. The active element has conical shape and it is larger in length than the parasitic monopole elements, this enables the dual-band operation. Thus, the proposed design is not only smaller than the conventional ESPAR antennas but it also achieves dual-band operation. Despite its compact design, the antenna has a peak gain of 6.3 dBi, which is equivalent to the gain of conventional ESPAR antennas. These characteristics make the antenna a good candidate for next generation communication systems. 展开更多
关键词 5G IOT ANTENNA Phased Array WIFI ESPAR WIRELESS
下载PDF
Impact of an active educational video game on children's motivation,science knowledge, and physical activity 被引量:3
8
作者 Haichun Sun Yong Gao 《Journal of Sport and Health Science》 SCIE 2016年第2期239-245,共7页
Background: Active educational video games (AVGs) appear to have a positive effect on elementary school students' motivation leading to enhanced learning outcomes. The purpose of this study was to identify the eff... Background: Active educational video games (AVGs) appear to have a positive effect on elementary school students' motivation leading to enhanced learning outcomes. The purpose of this study was to identify the effectiveness of an AVG on elementary school students' science knowledge learning, physical activity (PA) level, and interest-based motivation. Methods: In this randomized controlled study, 53 elementary school students were assigned to an experimental condition or a comparison condition. The experimental condition provided an AVG learning environment, whereas the comparison condition was based on sedentary educational video games. Results: The results of repeated measures analysis of variance (ANOVA) on the knowledge test showed that students in both groups performed better on the post-test than they did on the pre-test (p 〈 0.001, η2 = 0.486), and their post-test scores did not differ significantly. The experimental condition provided a more active environment since the students' average heart rates (HRs) were in the Target-Heart-Rate-Zone (HR = 134 bpm), which was significantly higher than the average HR (103 bpm) from the comparison condition (t = 7.212, p 〈 0.001). Students in the experimental condition perceived a higher level of situational interest than their counterparts in the comparison group (p 〈 0.01, and η2 = 0.301). Conclusion: These results suggest that AVGs benefit children more in terms of PA and motivation than traditional video games by providing an enjoyable learning experience and sufficient PA. 展开更多
关键词 Educational video game Exergame Heart rate INTENSITY INTEREST
下载PDF
FinTech in Taiwan:a case study of a Bank’s strategic planning for an investment in a FinTech company 被引量:3
9
作者 Jui-Long Hung Binjie Luo 《Financial Innovation》 2016年第1期186-201,共16页
Introduction:Since 2015 is the year of FinTech in Taiwan,it is worth investigating the challenges that emerged when banks were encouraged to invest in FinTech companies for collaboration.This study aims to identify th... Introduction:Since 2015 is the year of FinTech in Taiwan,it is worth investigating the challenges that emerged when banks were encouraged to invest in FinTech companies for collaboration.This study aims to identify the strategic considerations in the process of searching for FinTech investment targets.Case description:This study used a case study investigation of a top-5 bank in Taiwan.The major data sources include the meeting notes of the FinTech investment task force and interviews with the team members.Co-opetition theory was adopted as the theoretical framework and interview questions were derived from the PARTS strategies in co-petition theory.The results relate to:(1)the strategic goals of FinTech investment,(2)the added value from FinTech companies,(3)criteria in selecting candidates in the same FinTech area,(4)choosing to work as either a cooperator or a competitor,and(5)barriers from policies and regulations.Discussion and evaluation:This study has several findings:(1)regulations and policies shape FinTech’s development;(2)banks,technology companies,and customers are not“FinTech ready;”(3)Compare top-down with bottom up strategies;(4)banks and FinTech companies have complex relationships;(5)it is unlikely that Taiwan will produce FinTech disruptors in the near future.Conclusion:The findings and discussion can benefit researchers and administrators in finance-related industries.More studies are desired to observe long-term development in terms of how companies collaborate or compete in specific FinTech areas. 展开更多
关键词 FinTech Taiwan FinTech Industry Investment in FinTech Bank 3.0 Taiwan bank industry Co-opetition Theory PARTS
下载PDF
Quasi in-situ EBSD analysis of twinning-detwinning and slip behaviors in textured AZ31 magnesium alloy subjected to compressive-tensile loading 被引量:2
10
作者 Yuzhi Zhu Dewen Hou Qizhen Li 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2022年第4期956-964,共9页
Twinning and detwinning behavior,together with slip behavior,are studied in a textured AZ31 magnesium alloy under compressive and tensile strains along the rolling direction(RD)after each interrupted mechanical test v... Twinning and detwinning behavior,together with slip behavior,are studied in a textured AZ31 magnesium alloy under compressive and tensile strains along the rolling direction(RD)after each interrupted mechanical test via quasi in-situ electron backscattered diffraction technique.The results show that twinning firstly takes place under the compressive strain along the RD.With the increasing compressive strain,{1012}tensile twins firstly nucleate,then propagate,and finally thicken.While under a reversed tensile strain along the RD,detwinning occurs.No nucleation happens during detwinning.Thus,tensile twins can detwin at lower tensile strain,followed by thinning,shortening,and vanishing.Slips are also activated to accommodate the plastic deformation.In the matrix,prismatic slip can only dominate at relatively high strains.Otherwise,basal slip dominates.While in the twins,prismatic slip can activate at lower strains,which is ascribed to the texture reorientation. 展开更多
关键词 Magnesium alloy TWINNING Detwinning Prismatic slip quasi in-situ EBSD
下载PDF
Nigral dopaminergic neuron replenishment in adult mice through VE-cadherin-expressing neural progenitor cells 被引量:1
11
作者 Abir A.Rahman Nathan K.Lai +3 位作者 Joshua E.Albright Paige E.Urquhart Abby R.Webb Brad E.Morrison 《Neural Regeneration Research》 SCIE CAS CSCD 2017年第11期1865-1869,共5页
The function of dopaminergic neurons in the substantia nigra is of central importance to the coordination of movement by the brain's basal ganglia circuitry. This is evidenced by the loss of these neurons, resulting ... The function of dopaminergic neurons in the substantia nigra is of central importance to the coordination of movement by the brain's basal ganglia circuitry. This is evidenced by the loss of these neurons, resulting in the cardinal motor deficits associated with Parkinson's disease. In order to fully understand the physiology of these key neurons and develop potential therapies for their loss, it is essential to determine if and how dopaminergic neurons are replenished in the adult brain. Recent work has presented evidence for adult neurogenesis of these neurons by Nestin+/Sox2 neural progenitor cells. We sought to further validate this finding and explore a potential atypical origin for these progenitor cells. Since neural progenitor cells have a proximal association with the vasculature of the brain and subsets of endothelial cells are Nestin+, we hypothesized that dopaminergic neural progenitors might share a common cell lineage. Therefore, we employed a VE-cadherin promoter-driven CREERT2:TIlox/Tlox transgenic mouse line to ablate the tyrosine hydroxylase gene from endothelial cells in adult animals. After 26 weeks, but not 13 weeks, following the genetic blockade of tyrosine hydroxylase expression in VE-cadherin+ cells, we observed a significant reduction in tyrosine hydroxylase+ neurons in the substantia nigra. The results from this genetic lineage tracing study suggest that dopaminergic neurons are replenished in adult mice by a VE-cadherin+ progenitor cell population potentially arising from an endothelial lineage. 展开更多
关键词 nerve regeneration neural progenitor cells adult neurogenesis endothelial cells substantia nigra dopaminergic neurons Parkinson's disease mouse model
下载PDF
Discovery of nigral dopaminergic neurogenesis in adult mice 被引量:5
12
作者 Brad E.Morrison 《Neural Regeneration Research》 SCIE CAS CSCD 2016年第6期878-881,共4页
Parkinson's disease is characterized by the loss of dopaminergic neurons in the substantia nigra. As a result, intensive efforts have focused upon mechanisms that facilitate the death of mature dopaminergic neurons. ... Parkinson's disease is characterized by the loss of dopaminergic neurons in the substantia nigra. As a result, intensive efforts have focused upon mechanisms that facilitate the death of mature dopaminergic neurons. Unfortunately, these efforts have been unsuccessful in providing an effective treatment to address neurodegeneration in this disease. Therefore, alternative theories of pathogenesis are being explored. Adult neurogenesis of dopaminergic neurons is an attractive concept that would provide a possible mechanism of neurodegeneration as well as offer an endogenous means to replenish affected neurons. To determine whether dopaminergic neurons experience neurogenesis in adult mice we developed a novel cell lineage tracing model that permitted detection of neurogenesis without many of the issues associated with popular techniques. Remarkably, we discovered that dopaminergic neurons are replenished in adult mice by Nestin+/Sox2- progenitor cells. What's more, the rate of neurogenesis is similar to the rate of dopaminergic neuron loss reported using a chronic, systemic inflammatory response mouse model. This observation may indicate that neuron loss in Parkinson's disease results from inhibition of neurogenesis. 展开更多
关键词 substantia nigra progenitor tamoxifen pathogenesis endogenous mature attractive hydroxylase providing
下载PDF
Measurement invariance and latent mean differences of the Chinese version physical activity self-efficacy scale across gender and education levels 被引量:1
13
作者 Han Chen Jun Dai Yong Gao 《Journal of Sport and Health Science》 SCIE 2019年第1期46-54,共9页
Background: Self-efficacy has been identified as an important determinant of youth's behavior change including physical activity(PA) participation. However, the dimensionality check of a PA self-efficacy scale has... Background: Self-efficacy has been identified as an important determinant of youth's behavior change including physical activity(PA) participation. However, the dimensionality check of a PA self-efficacy scale has rarely been conducted in China. The current study aims to examine(1) the unidimensionality of a shortened Chinese version of PA self-efficacy scale(S-PASESC);(2) the measurement invariance of S-PASESC across gender and levels of education;(3) the latent factor mean difference between gender and levels of education;(4) the direct effects of self-efficacy on PA by different gender and education levels; and(5) the comparisons of the direct effects of self-efficacy on PA across gender and education levels.Methods: The participants were 5 th through 11 th grade public school students recruited from 7 cities located in different geographic regions of China. The final data include a total of 3003 participants(49.7% boys) who have completed the scales.Results: Confirmatory factor analysis(CFA) test supported the unidimensionality of S-PASESC. The S-PASESC is invariant across gender and 3 levels of education at both configural, full metric, and full scalar levels. Findings from latent mean comparisons showed that boys reported higher PA self-efficacy than girls. Students' perceived PA self-efficacy tend to decrease from elementary to high school. Finally, self-efficacy positively related to PA by groups of different gender and education levels and the relationship between self-efficacy and PA is stronger among middle school boys than girls.Conclusion: Findings suggest S-PASESC is a valid scale for measuring Chinese students' PA self-efficacy. 展开更多
关键词 Chinese adolescents Education levels Factor analysis GENDER LATENT mean comparison MEASUREMENT INVARIANCE Physical activity SELF-EFFICACY scale
下载PDF
Volcano video data characterized and classified using computer vision and machine learning algorithms 被引量:1
14
作者 Alex J.C.Witsil Jeffrey B.Johnson 《Geoscience Frontiers》 SCIE CAS CSCD 2020年第5期1789-1803,共15页
Video cameras are common at volcano observatories,but their utility is often limited during periods of crisis due to the large data volume from continuous acquisition and time requirements for manual analysis.For came... Video cameras are common at volcano observatories,but their utility is often limited during periods of crisis due to the large data volume from continuous acquisition and time requirements for manual analysis.For cameras to serve as effective monitoring tools,video frames must be synthesized into relevant time series signals and further analyzed to classify and characterize observable activity.In this study,we use computer vision and machine learning algorithms to identify periods of volcanic activity and quantify plume rise velocities from video observations.Data were collected at Villarrica Volcano,Chile from two visible band cameras located^17 km from the vent that recorded at 0.1 and 30 frames per second between February and April 2015.Over these two months,Villarrica exhibited a diverse range of eruptive activity,including a paroxysmal eruption on 3 March.Prior to and after the eruption,activity included nighttime incandescence,dark and light emissions,inactivity,and periods of cloud cover.We quantify the color and spatial extent of plume emissions using a blob detection algorithm,whose outputs are fed into a trained artificial neural network that categorizes the observable activity into five classes.Activity shifts from primarily nighttime incandescence to ash emissions following the 3 March paroxysm,which likely relates to the reemergence of the buried lava lake.Time periods exhibiting plume emissions are further analyzed using a row and column projection algorithm that identifies plume onsets and calculates apparent plume horizontal and vertical rise velocities.Plume onsets are episodic,occurring with an average period of^50 s and suggests a puffing style of degassing,which is commonly observed at Villarrica.However,the lack of clear acoustic transients in the accompanying infrasound record suggests puffing may be controlled by atmospheric effects rather than a degassing regime at the vent.Methods presented here offer a generalized toolset for volcano monitors to classify and track emission statistics at a variety of volcanoes to better monitor periods of unrest and ultimately forecast major eruptions. 展开更多
关键词 Volcano monitoring Plume exit velocity Volcano webcam Image processing Machine learning Villarrica
下载PDF
Study on Air-Purifying Performance of Semi-Flexible Asphalt Samples Coated with Titanium Dioxide Using Different Methods 被引量:1
15
作者 Shoujing Yan Yangyang Wang +3 位作者 Fengxia Chi Xue Luo Tianjie Zhang Chenchen Xi 《Journal of Renewable Materials》 SCIE EI 2022年第5期1321-1335,共15页
Titanium dioxide(TiO_(2))was recently employed to apply onto road surfaces to degrade the harmful compounds from vehicle emissions.However,it remains a challenging task to find a highly compatible pavement type for Ti... Titanium dioxide(TiO_(2))was recently employed to apply onto road surfaces to degrade the harmful compounds from vehicle emissions.However,it remains a challenging task to find a highly compatible pavement type for TiO_(2)application to achieve durable and efficient air-purifying performance.This study proposed to coat TiO_(2)particles onto semi-flexible pavement surface and tried to investigate an optimum coating method.Three coating methods,including direct mixing TiO_(2)(MT)with asphalt mixture,spraying dry TiO_(2)(ST)coating and watersolution-based TiO_(2)(WT)coating on semi-flexible pavement surface.To achieve this objective,semi-flexible samples were prepared to evaluate and compare the performances of three coating methods by employing resistance to wearing,NO removal efficiency tests and residual texture depth tests.It was found that the ST method not only provided better NO degrading efficiency but also improved the resistance to wearing than the other two methods. 展开更多
关键词 Titanium dioxide air-purifying performance semi-flexible pavement coating methods
下载PDF
Calibration of SWAT2009 Using Crop Biomass, Evapotranspiration, and Deep Recharge: Calera Watershed in Zacatecas, Mexico Case Study 被引量:1
16
作者 Jose R. ávila-Carrasco Francisco Mojarro Dávila +10 位作者 Daniel N. Moriasi Prasanna H. Gowda Carlos Bautista-Capetillo Francisco G. Echavarria-Cháirez Jurgen D. Garbrecht Jean L. Steiner Terry A. Howell Edward T. Kanemasu Alan J. Verser Kevin Wagner Jairo Hernandez 《Journal of Water Resource and Protection》 2012年第7期439-450,共12页
Groundwater is the main source of water in the semi-arid Calera watershed, located in the State of Zacatecas, Mexico. Due to increasing population, rapid industrial growth, and increased irrigation to meet growing foo... Groundwater is the main source of water in the semi-arid Calera watershed, located in the State of Zacatecas, Mexico. Due to increasing population, rapid industrial growth, and increased irrigation to meet growing food demand, groundwater extraction in the Calera watershed are exceeding recharge rates. Therefore, development and evaluation of alter-native water management strategies are needed for sustainable development of the region. The Soil and Water Assessment Tool (SWAT) model was selected for this purpose as it has been used to simulate a wide range of agricultural production, the extensive testing and application in diverse watersheds worldwide, and the potential for future linkage of this model to groundwater models. However, crucial flow data which are commonly used for calibrating hydrologic models are not available in this watershed. This paper describes a novel calibration methodology that uses biomass and water balance approach which has potential for calibration of hydrologic models in ungauged or data-scarce watersheds, which are prevalent in many parts of the world. Estimated long-term annual average actual evapotranspiration (AET), and deep aquifer recharge rates and plant biomass values based on the expert knowledge of researchers and managers in the watershed were used as targets for calibration. The model performance was assessed using the Nash-Sutcliffe effi-ciency coefficient (NSE), coefficient of determination (R2), and percent bias (PBIAS, %) statistics. On average, the calibrated SWAT model yielded annual Nash-Sutcliffe efficiency coefficient values of 0.95, 0.99, and 0.85 for AET, recharge, and biomass, respectively. The coefficient of determination, values for AET, recharge, and biomass were 0.95, 0.94, and 0.99 respectively. The percent bias values of ±2.21%, ±0.18%, and ±0.96% for AET, recharge, and biomass, respectively, indicated that the model reproduced the calibration target values of the three water budget variables within an acceptable value of ± 10.0%. Therefore, it is concluded that the calibrated SWAT model can be used in evaluating alternative water management scenarios for the Calera watershed without further validation. Considering the relative ease in developing calibration data and excellent performance statistics, the calibration methodology proposed in this study may have the potential to be used for ungauged or data-scare agricultural watersheds that are prevalent in many parts of the world. 展开更多
关键词 SWAT Calera WATERSHED Scenarios RECHARGE EVAPOTRANSPIRATION RUNOFF Erosion
下载PDF
It Takes Two to Tango: Entrepreneurship and Creativity in Troubled Times--Vietnam 2012 被引量:2
17
作者 Nancy K. Napier Dang Le Nguyen Vu Quan Hoang Vuong 《Sociology Study》 2012年第9期662-674,共13页
This study focuses on perceived values of entrepreneurship and creativity within a turbulent environment. The initial hypothesis is that a typical entrepreneurial process carries with its "creativity-enabling element... This study focuses on perceived values of entrepreneurship and creativity within a turbulent environment. The initial hypothesis is that a typical entrepreneurial process carries with its "creativity-enabling elements". In a normal situation, businesses focus on optimizing their resources for commercial gains, thus perceptions about values of entrepreneurial creativity are usually vague. However, in difficult times, the difference between survival and failure may be creativity. This paper examines many previous findings on entrepreneurship and creativity, and suggests a highly possible "organic growth" of creativity in an entrepreneurial environment and reinforcing value of entrepreneurship when creativity power is present. In other words, the authors see each idea reinforcing the other. The authors survey Vietnamese firms during the chaotic year of 2012 to learn about the "entrepreneurship-creativity nexus", looking at influential cultural values, namely risk tolerance, relationship, and dependence on resources--to assess how they influence entrepreneurial decisions. A set of 137 qualified responses was obtained for this statistical examination. A categorical data analysis is performed to confirm that creativity and entrepreneurial spirit could hardly be separate, for both entrepreneurial and accomplished companies. Although the most important factor during implementation is still "relationship", business people are increasingly aware of the need of creativity/innovation in troubled times. 展开更多
关键词 CREATIVITY ENTREPRENEURSHIP economic transition VIETNAM
下载PDF
Mechanical suppression of breast cancer cell invasion and paracrine signaling to osteoclasts requires nucleo-cytoskeletal connectivity 被引量:1
18
作者 Xin Yi Laura E.Wright +8 位作者 Gabriel M.Pagnotti Gunes Uzer Katherine M.Powell Joseph M.Wallace Uma Sankar Clinton T.Rubin Khalid Mohammad Theresa A.Guise William R.Thompson 《Bone Research》 SCIE CAS CSCD 2020年第4期393-405,共13页
Exercise benefits the musculoskeletal system and reduces the effects of cancer.The effects of exercise are multifactorial,where metabolic changes and tissue adaptation influence outcomes.Mechanical signals,a principal... Exercise benefits the musculoskeletal system and reduces the effects of cancer.The effects of exercise are multifactorial,where metabolic changes and tissue adaptation influence outcomes.Mechanical signals,a principal component of exercise,are anabolic to the musculoskeletal system and restrict cancer progression.We examined the mechanisms through which cancer cells sense and respond to low-magnitude mechanical signals introduced in the form of vibration.Low-magnitude,high-frequency vibration was applied to human breast cancer cells in the form of low-intensity vibration(LIV).LIV decreased matrix invasion and impaired secretion of osteolytic factors PTHLH,IL-11,and RANKL.Furthermore,paracrine signals from mechanically stimulated cancer cells,reduced osteoclast differentiation and resorptive capacity.Disconnecting the nucleus by knockdown of SUN1 and SUN2 impaired LIV-mediated suppression of invasion and osteolytic factor secretion.LIV increased cell stiffness;an effect dependent on the LINC complex.These data show that mechanical vibration reduces the metastatic potential of human breast cancer cells,where the nucleus serves as a mechanosensory apparatus to alter cell structure and intercellular signaling. 展开更多
关键词 INVASION IMPAIRED SKELETAL
下载PDF
Imposing Active Sources during High-Frequency Passive Surface-Wave Measurement 被引量:6
19
作者 Feng Cheng Jianghai Xia +3 位作者 Chao Shen Yue Hu Zongbo Xu Binbin Mi 《Engineering》 2018年第5期685-693,共9页
Passive surface-wave utilization has been intensively studied as a means of compensating for the short-age of low-frequency information in active surface-wave measurement, In general, passive surface-wave methods cann... Passive surface-wave utilization has been intensively studied as a means of compensating for the short-age of low-frequency information in active surface-wave measurement, In general, passive surface-wave methods cannot provide phase velocities up to several tens of hertz; thus, active surface-wave methods are often required in order to increase the frequency range, To reduce the amount of field work, we pro-pose a strategy for a high-frequency passive surface-wave survey that imposes active sources during con-tinuous passive surface-wave observation; we call our strategy "mixed-source surface-wave (MSW) measurement," Short-duration (within 10 min) passive surface waves and mixed-source surface waves were recorded at three sites with different noise levels: namely, inside a school, along a road, and along a railway, Spectral analysis indicates that the high-frequency energy is improved by imposing active sources during continuous passive surface-wave observation, The spatial autocorrelation (SPAC) method and the multichannel analysis of passive surface waves (MAPS) method based on cross-correlations were performed on the recorded time sequences, The results demonstrate the flexibility and applicability of the proposed method for high-frequency phase velocity analysis, We suggest that it will be constructive to perform MSW measurement in a seismic investigation, rather than exclusively performing either active surface-wave measurement or passive surface-wave measurement, 展开更多
关键词 Passive surface wave Active surface wave High frequency Mixed-source surface wave Spatial autocorrelation Multichannel analysis of passive surface WAVES
下载PDF
Reverse-Time Migration from Rugged Topography to Image Ground-Penetrating Radar Data in Complex Environments 被引量:5
20
作者 John H. Bradford Janna Privette +1 位作者 David Wilkins Richard Ford 《Engineering》 2018年第5期661-666,共6页
In ground-penetrating radar (GPR) imaging, it is common for the depth of investigation to be on the same order as the variability in surface topography, In such cases, migration fails when it is carried out from a d... In ground-penetrating radar (GPR) imaging, it is common for the depth of investigation to be on the same order as the variability in surface topography, In such cases, migration fails when it is carried out from a datum after the application of elevation statics, We introduce a reverse-time migration (RTM) algorithm based on the second-order decoupled form of Maxwell's equations, which requires computation of only the electric field, The wavefield extrapolation is computed directly from the acquisition surface without the need for datuming, In a synthetic case study, the algorithm significantly improves image accuracy over a processing sequence in which migration is performed after elevation statics, In addition, we acquired a field dataset at the Coral Pink Sand Dunes (CPSD) in Utah, USA, The data were acquired over rugged topography and have the complex internal stratigraphy of multiply eroded, modern, and ancient eolian deposits, The RTM algorithm significantly improves radar depth images in this challenging environment, 展开更多
关键词 Ground-penetrating radar Reverse-time migration Sand dune Amplitude analysis
下载PDF
上一页 1 2 3 下一页 到第
使用帮助 返回顶部