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Dynamic signal control for at-grade intersections under preliminary autonomous vehicle environment 被引量:3
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作者 LUO Si-da ZHANG Shuai 《Journal of Central South University》 SCIE EI CAS CSCD 2019年第4期893-904,共12页
Autonomous vehicle technology will transform fundamentally urban traffic systems.To better enhance the coming era of connected and autonomous vehicles,effective control strategies that interact wisely with these intel... Autonomous vehicle technology will transform fundamentally urban traffic systems.To better enhance the coming era of connected and autonomous vehicles,effective control strategies that interact wisely with these intelligent vehicles for signalized at-grade intersections are indispensable.Vehicle-to-infrastructure communication technology offers unprecedented clues to reduce the delay at signalized intersections by innovative information-based control strategies.This paper proposes a new dynamic control strategy for signalized intersections with vehicle-to-signal information.The proposed strategy is called periodic vehicle holding(PVH)strategy while the traffic signal can provide information for the vehicles that are approaching an intersection.Under preliminary autonomous vehicle(PAV)environment,left-turning and through-moving vehicles will be sorted based on different information they receive.The paper shows how PVH reorganizes traffic to increase the capacity of an intersection without causing severe spillback to the upstream intersection.Results show that PVH can reduce the delay by approximately 15%at a signalized intersection under relatively high traffic demand. 展开更多
关键词 dynamic traffic control vehicle-to-signal signalized intersection preliminary autonomous vehicle environment
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Impacts of land use and climate change on regional net primary productivity 被引量:8
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作者 高志强 刘纪远 +4 位作者 曹明奎 LI Kerang TAO Bo 《Journal of Geographical Sciences》 SCIE CSCD 2004年第3期349-358,共10页
Combined with recent historical climate data and two periods of land use datasets from remote sensing data, we test the net primary productivity (NPP) data sets in North Chinamodelled by the satellite data-driven Glob... Combined with recent historical climate data and two periods of land use datasets from remote sensing data, we test the net primary productivity (NPP) data sets in North Chinamodelled by the satellite data-driven Global Production Efficiency Model (GLO-PEM) for detecting thewidespread spatial and temporal characteristics of the impacts of climate and land use change onthe regional NPP. Our results show that over the past 20 years, the mean annual temperature in thestudy region has remarkably increased by more than 0.064 ℃, but over the same period, there hasbeen a 1.49 mm decrease in annual precipitation and decrease in NPP by an annual rate of 6.9 TgC.The NPP changes in the study region were greatly affected by the average temperature andprecipitation by ten-day periods as well as the seasonal temperature and precipitation in the studyregion. The correlation between seasonal NPP and seasonal precipitation and temperature is highlyconsistent with land cover spatially, and the correlation coefficient changes with the changes ofvegetation types. The analysis reveals that the related areas in land use change only take up 5.45%of the whole studied region, so the climate changes dominate the impacts on the NPP in the wholestudy region (90% of the total). However, land use plays an absolute dominative role in areas withland cover changes, accounting for 97% of the total. From 1981 to 2000, the NPP in the whole studyregion remarkably reduced due to obvious precipitation decrease and temperature rise. Between twoperiods of land use (about 10 years), the changes in climate are predicted to promote a decrease inNPP by 78 ( + -0.6) TgC, and integrated impacts of climate changes and land use to promote adecrease in NPP by 87(+-0.8) TgC. 展开更多
关键词 climate change land use change NPP GLO-PEM North China Northeast China
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Effect of human milk and colostrum on Entamoeba histolytica 被引量:1
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作者 Ciler Akisu Umit Aksoy +2 位作者 Hasan Cetin Sebnem Ustun Mete Akisu 《World Journal of Gastroenterology》 SCIE CAS CSCD 2004年第5期741-742,共2页
AIM:Many defense factors of the mother's colostrum or milk protect infants from intestinal, respiratory and systemic infections. In the present study, we investigated the effect of colostrum and mature human milk ... AIM:Many defense factors of the mother's colostrum or milk protect infants from intestinal, respiratory and systemic infections. In the present study, we investigated the effect of colostrum and mature human milk on E. histolytica parasites in vitro.METHODS:Samples of human milk were collected from 5 healthy lactating mothers.The medium with human milk at concentrations of 2%, 5% and 10% was obtained.RESULTS:The lethal effect of E. histolytica on the medium supplemented with different concentrations of both colostrum and mature human milk was significant during the first 30min. We also detected that the results of colostrum and mature human milk were similar. No statistically significant differences were found between same concentrations of colostrum and mature human milk at the same times.CONCLUSION:Colostrum and mature human milk have significant lethal effect on E. histolytica and protect against its infection in breast fed children. 展开更多
关键词 ANIMALS COLOSTRUM Entamoeba histolytica development Entamoebiasis control FEMALE Humans In Vitro INFANT Milk Human
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Population-based study of DNA image cytometry as screening method for esophageal cancer 被引量:15
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作者 Lin Zhao,Wen-Qiang Wei,Xin-Qing Li,Guo-Qing Wang,Qi Shang,You-Lin Qiao,Department of Cancer Epidemiology,Cancer Institute/Hospital,Chinese Academy of Medical Sciences and Peking Union Medical College,Beijing 100021,China De-Li Zhao,Department of Epidemiology,Feicheng People’s Hospital,Feicheng 271600,Shandong Province,China Chang-Qing Hao,Department of Endoscopy,Linzhou Cancer Hospital,Linzhou 456500,Henan Province,China Dong-Mei Lin,Qin-Jing Pan,Department of Pathology,Cancer Institute/Hospital,Chinese Academy of Medical Sciences and Peking Union Medical College,Beijing 100021,China Fu-Hua Lei,Department of Pathology,Feicheng People’s Hospi-tal,Feicheng 271600,Shandong Province,China Jin-Wu Wang,Department of Pathology,Linzhou Cancer Hospi-tal,Linzhou 456500,Henan Province,China 《World Journal of Gastroenterology》 SCIE CAS CSCD 2012年第4期375-382,共8页
AIM:To explore the DNA image cytometry (DNA-ICM) technique as a primary screening method for esopha-geal squamous precancerous lesions.METHODS:This study was designed as a population-based screening study.A total of 5... AIM:To explore the DNA image cytometry (DNA-ICM) technique as a primary screening method for esopha-geal squamous precancerous lesions.METHODS:This study was designed as a population-based screening study.A total of 582 local residents aged 40 years-69 years were recruited from Linzhou in Henan and Feicheng in Shandong.However,only 452 subjects had results of liquid-based cytology,DNA-ICM and pathology.The sensitivity and specificity of DNA-ICM were calculated and compared with liquid-based cytology in moderate dysplasia or worse.RESULTS:Sensitivities of DNA-ICM ranging from at least 1 to 4 aneuploid cells were 90.91%,86.36%,79.55% and 77.27%,respectively,which were better than that of liquid-based cytology (75%).Specifici-ties of DNA-ICM were 70.83%,84.07%,92.65% and 96.81%,but the specificity of liquid-based cytology was 91.91%.The sensitivity and specificity of a combination of liquid-based cytology and DNA-ICM were 84.09% and 85.78%,respectively.CONCLUSION:It is possible to use DNA-ICM tech-nique as a primary screening method for esophageal squamous precancerous lesions. 展开更多
关键词 DNA image cytometry ANEUPLOIDY Screen-ing Esophageal cancer Precancerous lesions
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Barriers to nurse-patient communication in primary healthcare centers in Bahrain:Patient perspective 被引量:1
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作者 Nada Mahmood Abdulla Rula Jamal Naqi Ghufran Ahmed Jassim 《International Journal of Nursing Sciences》 CSCD 2022年第2期230-235,I0008,共7页
Objectives:Effective and efficient communication is a core element in healthcare systems,especially between healthcare providers and patients.This study aimed to identify communication barriers be-tween nurses and pat... Objectives:Effective and efficient communication is a core element in healthcare systems,especially between healthcare providers and patients.This study aimed to identify communication barriers be-tween nurses and patients in primary healthcare centers in Bahrain.Methods:This is a cross-sectional study conducted across primary healthcare centers in Bahrain.Four hundred and two patients were recruited using convenience sampling.A self-administered question-naire comprising 29 items on communication barriers was used.Results:A total of 402 patients consented to participate.The majority of participants reported the following statements had large effects on communication:“shortage in the number of nurses compared to the large number of patients”(254/401,63.3%),“lack of desire of nurse to communicate with patients”(246/402,61.2%),and“negative attitude of the nurse toward the patient”(238/401,59.4%).Further,“difference in language between nurses and patients,”“lack of self-confidence by nurses,”and“nurses overwhelmed by work”were ranked as top three statements with a significant influence on commu-nication between nurses and patients.Conclusions:Communication between healthcare providers and patients is pivotal for an optimal healthcare service.Based on the findings of this study and the literature,we recommend formal training of health care workers in improving communication skills and including this not only in medical cur-riculum but also in the form of continuing medical education(CMEs)1. 展开更多
关键词 Communication barriers Delivery of health care Health personnel Primary health care Surveys and questionnaires
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Spatio-temporal Pattern of Net Primary Productivity in Hengduan Mountains area, China: Impacts of Climate Change and Human Activities 被引量:12
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作者 CHEN Tiantian PENG Li +1 位作者 LIU Shaoquan WANG Qiang 《Chinese Geographical Science》 SCIE CSCD 2017年第6期948-962,共15页
Net primary productivity(NPP), a metric used to define and identify changes in plant communities, is greatly affected by climate change, human activities and other factors. Here, we used the Carnegie-Ames-Stanford App... Net primary productivity(NPP), a metric used to define and identify changes in plant communities, is greatly affected by climate change, human activities and other factors. Here, we used the Carnegie-Ames-Stanford Approach(CASA) model to estimate the NPP of plant communities in Hengduan Mountains area of China, and to explore the relationship between NPP and altitude in this region. We examined the mechanisms underlying vegetation growth responses to climate change and quantitatively assessed the effects of ecological protection measures by partitioning the contributions of climate change and human activities to NPP changes. The results demonstrated that: 1) the average total and annual NPP values over the years were 209.15 Tg C and 468.06 g C/(m2·yr), respectively. Their trend increasingly fluctuated, with spatial distribution strongly linked to altitude(i.e., lower and higher NPP in high altitude and low altitude areas, respectively) and 2400 m represented the marginal altitude for vegetation differentiation; 2) areas where climate was the main factor affecting NPP accounted for 18.2% of the total research area, whereas human activities were the primary factor influencing NPP in 81.8% of the total research area, which indicated that human activity was the main force driving changes in NPP. Areas where climatic factors(i.e., temperature and precipitation) were the main driving factors occupied 13.6%(temperature) and 6.0%(precipitation) of the total research area, respectively. Therefore, the effect of temperature on NPP changes was stronger than that of precipitation; and 3) the majority of NPP residuals from 2001 to 2014 were positive, with human activities playing an active role in determining regional vegetation growth, possibly due to the return of farmland back to forest and natural forest protection. However, this positive trend is decreasing. This clearly shows the periodical nature of ecological projects and a lack of long-term effectiveness. 展开更多
关键词 net primary productivity (NPP) Carnegie-Ames-Stanford Approach (CASA) model climate change human activities Hengduan Mountains area
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Effects of Chlorfluazuron Sublethal Doses on Spermatogenesis of Adult Common Cutworm, Spodoptera fitura (F.) (Lepidoptera: Noctuidae)
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作者 Farzana Perveen 《Journal of Life Sciences》 2011年第11期933-941,共9页
Chlorfluazuron is an insect growth regulator for controlling the major insect pests in crops. This paper describes the effects of sublethal doses (LD10:1.00 ng/larva; LD3o: 3.75 ng/larva) of chlorfluazuron on sper... Chlorfluazuron is an insect growth regulator for controlling the major insect pests in crops. This paper describes the effects of sublethal doses (LD10:1.00 ng/larva; LD3o: 3.75 ng/larva) of chlorfluazuron on spermatogenesis in the adults of the common cutworm, Spodoptera litura (F.). Chlorfluazuron was applied topically to the newly-ecdysed fifth-instars ofS. litura under laboratory conditions. The secondary spermatocytes, spermatids, elongated spermatocytes with mature sperm and eupyrene sperm bundles were present in testis of newly emerged, 1 and 2 day-old adults, but gradually decreased in their numbers in the controls. However, the spermatogonia were not present in newly emerged, 1 and 2 day-old adults. Moreover, primary spermatocytes were present (174 ± 4.0) in newly emerged adults, but not found in 1 and 2 day-old adults. In the testes of newly emerged LD10-treated adults, the numbers of eupyrene and apyrene sperm bundles were significantly reduced compared with controls, and even significantly reduced in LD30-treated adults compared with LDlo, however, their ratios were not affected. Moreover, the pattern of spermatogenesis was the same in LD10- and LD30-treated male adults compared with controls. Furthermore, numbers of developing spermatocytes were significantly reduced in the LD10 compared with controls, and even significantly reduced in LD30-treated male adults compared with LD10. In newly emerged adults, the width and length of elongated spermatocytes with mature sperm were significantly reduced in LDlo- and more significantly reduced in LD30-treated compared with controls of S. litura. In vas deferens of untreated pre- and newly emerged adult male, both eupyrene and apyrene sperm bundles were found, however, in treated pre-adult male, only apyrene sperm bundles and in treated newly emerged adult male, fe, w eupyrene and numerous apyrene sperm bundles were found. It is concluded that spermatogenesis was significantly affected by chlorfluazuron. 展开更多
关键词 Adults CHLORFLUAZURON developing spermatocytes SPERMATOGENESIS Spodoptera litura sublethal doses
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Mechanism Research of Hg^0 Oxidation by Pulse Corona Induced Plasma Chemical Process
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作者 Hao Shuoshuo Chen Yang +3 位作者 Fan Yanxiang Yin Lianqing Zhang Liju Feng Qinzhong 《Journal of Environmental Science and Engineering(B)》 2016年第1期1-10,共10页
The oxidation of Hg^0 by Pulse Corona Induced Plasma Chemical Process (PPCP) was investigated through changing discharge voltage, pulse frequency and gas compositions. Experimental results indicate that active radic... The oxidation of Hg^0 by Pulse Corona Induced Plasma Chemical Process (PPCP) was investigated through changing discharge voltage, pulse frequency and gas compositions. Experimental results indicate that active radicals including O, O3 and OH can contribute to the oxidation of elemental mercury. 10 kV is the onset voltage, and the higher voltage the better removal efficiency. While with the increase of pulse frequency, the Hg^0 concentration falls rapidly at first but then rises rapidly. The best oxidation condition is at 12 kV and 600-800 PPS. Adding O2 can significantly promote oxidation. With NO and SO2 existed, there is an inhibition of mercury oxidation, and NO has a greater influence. Addition of HCl can promote oxidation slightly but affect the initial concentration of mercury significantly. Little moisture content can promote oxidation, while too much H2O can not only resist the oxidation, but also affect the initial concentration of mercury. The mercury oxidation rate can increase to 97.95% at 12 kV/800 PPS with the system of 10% 02/3% H2O/50 ppm HCI. However, mercury oxidation efficiency can reduce down to 20% with 100 ppm NO added. 展开更多
关键词 Non-thermal plasma MERCURY OXIDATION flue gas cleaning.
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Following Control for a UUV using Temporary Path Generation Guidance 被引量:2
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作者 Zheping Yan Dongnan Chi Jiajia Zhou Yufei Zhao 《Journal of Marine Science and Application》 2012年第2期236-243,共8页
A path following control algorithm for an unmanned underwater vehicle(UUV) using temporary path generation guidance was proposed in this paper.Owing to different initial states of the vehicle,such as position and or... A path following control algorithm for an unmanned underwater vehicle(UUV) using temporary path generation guidance was proposed in this paper.Owing to different initial states of the vehicle,such as position and orientation,the path following control in the horizontal plane may yield a poor performance.To deal with the negative effect induced by initial states,a temporary path generation was presented based on the relationship between the original reference path and the vehicle’s initial states.With different relative positions between the vehicle and reference path,including out of straight lines,as well as inside and outside a circle,the related temporary paths guiding the vehicle to the reference path were able to be generated in real time.The vehicle was guided to steer along the temporary path until it reached the tangent point at the reference path,where the controller was designed using the input-output feedback linearization method.Simulation results demonstrated that the proposed algorithm is effective under the three different situations mentioned above. 展开更多
关键词 nonlinear control path following control UUV temporary path generation input-output feedback linearization
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Challenges faced by community health nurses to achieve universal health coverage in Myanmar:A mixed methods study
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作者 Sein Yaw May Naw Clara +3 位作者 Ohn Khin Khin Win Win Mar Aye Nandar Han Su Su Maw 《International Journal of Nursing Sciences》 CSCD 2021年第3期271-278,I0002,I0003,共10页
Objective:This study aimed to identify the challenges of community health nurses(CHNs)in delivering effective community health care to achieve universal health coverage(UHC)in Myanmar.Methods:A total of 30 CHNs from t... Objective:This study aimed to identify the challenges of community health nurses(CHNs)in delivering effective community health care to achieve universal health coverage(UHC)in Myanmar.Methods:A total of 30 CHNs from township health centers in the northeastern,southern,and western parts of Myanmar were purposefully recruited for quantitative and qualitative interviews.Quantitative data were processed using Microsoft Excel software,and qualitative data were analyzed using thematic analysis.This study is registered with researchregistry6201.Results:Around the country,30 CHNs uncovered their hardships in implementing primary health care to achieve UHC.Over 90%of the participants agreed to the problem of inadequate health infrastructure,while half of them felt unmotivated when they encountered role conflicts among various cadres of healthcare providers and poor opportunities for career promotion.Major problems arose from the lack of standard professional education at the entry point to community settings because most CHNs did not achieve specialized training in providing public health services.Complications are incapable of evaluating health services for policy-making and the inability to conduct health research to develop evidencebased practices.Insecure work and living conditions,unsupportive community relationships,and undereducation in professional practices were supportive major themes explored by CHNs to achieve a deeper understanding of the barriers to UHC.Not only the health system itself but also the population and other geographical factors have contributed to many challenges to CHNs.Conclusion:Myanmar’s CHNs face many challenges in achieving UHC.These challenges are not confined to the health sector.Some situations,such as geographical barriers and transportation problems,remain persistent challenges for healthcare providers.This study highlights the fact that current health systems should be strengthened by qualified healthcare providers and sufficient infrastructure.Meanwhile,public empowerment plays a critical role in promoting health development. 展开更多
关键词 Community health nurses Community health services Health personnel Myanmar Primary health care Professional practice Social conditions Universal health coverage
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Standing Crop and Primary Production of Benthic Microalgae on the Tidal Flats in Yueqing Bay
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作者 HAO Qiang CAI Yuming +3 位作者 NING Xiuren LIU Chenggang PENG Xin TANG Xuexi 《Journal of Ocean University of China》 SCIE CAS 2011年第2期157-164,共8页
The standing stock and primary production of benthic microalgae on tidal flats were measured seasonally at 3 transects (Puqing, Dahengchuang and Puqi) in Yueqing Bay during 2002 2003. The results showed that the integ... The standing stock and primary production of benthic microalgae on tidal flats were measured seasonally at 3 transects (Puqing, Dahengchuang and Puqi) in Yueqing Bay during 2002 2003. The results showed that the integral chlorophyll a (Chl a) concentration in tidal flat mud exhibited a seasonal variation with the order of magnitude: winter (14.0 4.2 mg m-2) > spring (13.0 6.3 mg m-2) > autumn (7.7 5.9 mg m-2) > summer (4.6 3.2 mg m-2). The primary production showed an order of magnitude: spring (270.5 224.9 mgC m-2 d-1)>winter (238.7 225.5 mgC m-2 d-1)>autumn (214.1 56.2 mgC m-2 d-1)>summer (71.6 44.6 mgC m-2 d-1). Both chlorophyll a and primary production showed maximum values in the surface layer of sediment, and decreased rapidly with increasing depth due to sun light limitation. The results of variance analysis indicated that seasonal variation and tidal flat condition affected Chl a greatly, but had no significant effect on primary production. The annual primary production of benthic microalgae on tidal flats in Yueqing Bay was estimated at 16143 tons carbon, which is sufficient to support 1.02×105 tons shellfish production. The environmental factors affecting chlorophyll and primary production on the tidal flats in Yueqing Bay were discussed. By comparing with other bays on China's coast, it was observed that Yueqing Bay is a region with high benthic microalgae standing crop and primary production, which may be related to the type of its sediment. 展开更多
关键词 chlorophyll a primary production benthic microalgae tidal flat Yueqing Bay
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张三丰生卒年代考及生平考 被引量:1
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作者 徐平 《儒道研究》 2014年第1期68-91,共24页
张三丰生卒年代考张三丰的生卒年代引起学者的考据热情,但因确切材料缺乏,致使学者考据结果各异。有人考证张三丰为元末明初人,比如黄兆汉的《明代道士张三丰考》持这一观点;有人考证张三丰为宋末元初人,比如清代汪锡龄(1664~1724)《张... 张三丰生卒年代考张三丰的生卒年代引起学者的考据热情,但因确切材料缺乏,致使学者考据结果各异。有人考证张三丰为元末明初人,比如黄兆汉的《明代道士张三丰考》持这一观点;有人考证张三丰为宋末元初人,比如清代汪锡龄(1664~1724)《张三丰本传》持这一观点;有人考证张三丰为金时人,比如何乔远的《名山藏》持这种说法;有人考证张三丰为五代时人。 展开更多
关键词 生平 初人 热情 考据 生卒 学者 观点
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继续教育的初心及其实现路径 被引量:1
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作者 王真真 《当代继续教育》 2020年第5期11-16,共6页
继续教育的初心在于促进成人主动、多元化和差异化的发展。然而,目前继续教育实践中存在着初心背离的种种问题,成人的学习需求被遮蔽、经验被忽视、主体性发挥为他为性干预所替代。今后,成人院校应视成人学员本身为教学的出发点和落脚点... 继续教育的初心在于促进成人主动、多元化和差异化的发展。然而,目前继续教育实践中存在着初心背离的种种问题,成人的学习需求被遮蔽、经验被忽视、主体性发挥为他为性干预所替代。今后,成人院校应视成人学员本身为教学的出发点和落脚点,以成人学习需求为教学起点,以成人学习经验和学习主体性为教学介质,促进成人主动、多元化和差异化的发展。 展开更多
关键词 继续教育 初人 初心 成人发展
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天主教信仰与教育的社会作用——上海天主教在促进社会和谐与社会道德建设中的作用的调查报告
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作者 谢华 蔡翼伦 +2 位作者 周永 夏徽 张湛 《基督教学术》 2009年第1期182-210,280,共30页
一、和谐社会:一个信仰上和政冶上的观念“缔造和平的人是有福的,因为他们要称为天主的子女。”(玛5:9)《圣经·创世记》一至二章描绘了一幅创世之初人与天主、人与人、人与自然界和谐相处的美好图画。在天主教的信仰中,这一图景虽... 一、和谐社会:一个信仰上和政冶上的观念“缔造和平的人是有福的,因为他们要称为天主的子女。”(玛5:9)《圣经·创世记》一至二章描绘了一幅创世之初人与天主、人与人、人与自然界和谐相处的美好图画。在天主教的信仰中,这一图景虽被人的私心与骄傲所破坏,并由之导致了种种自然之恶与伦理之恶的产生,但天主通过其圣子耶稣基督的受难与复活,以十字架的奥迹战胜了罪恶、更新了世界、成就了和平;这一和平即使还没有在人间广泛实现, 但它既是天主对相信他的人的不变的允诺, 是信众的希望, 也是基督的教会在世的努力方向和对信徒的要求. 展开更多
关键词 初人 社会 天主 十字架 信仰 奥迹 战胜 耶稣基督
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天主教信仰与伦理在促进和谐社会建设中的作用
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作者 谢华 《基督宗教研究》 2007年第1期420-444,共25页
1.和谐社会:一个信仰上和政冶上的观念缔造和平的人是有福的,因为他们要称为天主的子女。(玛5:9)《圣经·创世记》一至二章描绘了一幅创世之初人与天主、人与人、人与自然界和谐相处的美好图画。在天主教的信仰中,这一图景虽被人的... 1.和谐社会:一个信仰上和政冶上的观念缔造和平的人是有福的,因为他们要称为天主的子女。(玛5:9)《圣经·创世记》一至二章描绘了一幅创世之初人与天主、人与人、人与自然界和谐相处的美好图画。在天主教的信仰中,这一图景虽被人的私心与骄傲所破坏,并由之导致了种种自然之恶与伦理之恶的产生,但天主通过其圣子耶稣基督的受难与复活,以十字架的奥迹战胜了罪恶、更新了世界、成就了和平. 展开更多
关键词 初人 天主 罪恶 伦理 信仰 奥迹 战胜 耶稣基督
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EXTINCTION AND WAVEFRONT IN AN AGE-STRUCTURED POPULATION MODEL ON INFINITE PATCHES WITH DISTRIBUTED MATURATION DELAY 被引量:2
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作者 LING Jiaoxiu WENG Peixuan 《Journal of Systems Science & Complexity》 SCIE EI CSCD 2005年第4期464-477,共14页
In this paper, we derive a lattice model for a single species on infinite patches of one-dimensional space with that the maturation could occur at any age. The formulation involves a distribution of possible ages of m... In this paper, we derive a lattice model for a single species on infinite patches of one-dimensional space with that the maturation could occur at any age. The formulation involves a distribution of possible ages of maturation and a probability density function on which ecological assumptions are made. The following results are obtained: the existence and isotropy of the unique nonnegative solution for initial value problem, the extinction of the species provided with the non-existence of positive equilibria, and the existence of wavefronts with the wave speed c 〉 c*. 展开更多
关键词 AGE-STRUCTURE distributed mature delay initial value problem extinction wave front.
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Quantitative Assessment of the Effects of Climate Change and Human Activities on Grassland NPP in Altay Prefecture 被引量:2
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作者 TIAN Jie XIONG Junnan +4 位作者 ZHANG Yichi CHENG Weiming HE Yuchuan YE Chongchong HE Wen 《Journal of Resources and Ecology》 CSCD 2021年第6期743-756,共14页
Grassland degradation in Altay Prefecture is of considerable concern as it is a threat that hinders the sustainable development of the local economy and the stable operation of the livestock industry.Quantitative asse... Grassland degradation in Altay Prefecture is of considerable concern as it is a threat that hinders the sustainable development of the local economy and the stable operation of the livestock industry.Quantitative assessment of the relative contributions of climate change and human activities,which are considered as the dominant triggers of grassland degradation,to grassland variation is crucial for understanding the grassland degradation mechanism and mitigating the degraded grassland in Altay Prefecture.In this paper,the Carnegie-Ames-Stanford Approach model and the Thornthwaite memorial model were adopted to simulate the actual net primary productivity(NPP_(A))and potential net primary productivity(NPP_(P))in the Altay Prefecture from 2000 to 2019.Meanwhile,the difference between potential NPP and actual NPP was employed to reflect the effects of human activities(NPP_(H))on the grassland.On this basis,we validated the viability of the simulated NPP using the Pearson correlation coefficient,investigated the spatiotemporal variability of grassland productivity,and established comprehensive scenarios to quantitatively assess the relative roles of climate change and human activities on grassland in Altay prefecture.The results indicate three main points.(1)The simulated NPP_(A) was highly consistent with the MOD17 A3 dataset in spatial distribution.(2)Regions with an increased NPP_(A) accounted for 70.53% of the total grassland,whereas 29.47% of the total grassland area experienced a decrease.At the temporal scale,the NPP_(A) presented a slightly increasing trend(0.83 g C m^(-2) yr^(-1))over the study period,while the trends of NPP_(P) and NPP_(H) were reduced(-1.31 and-2.15 g C m^(-2) yr^(-1)).(3)Compared with climate change,human activities played a key role in the process of grassland restoration,as 66.98% of restored grassland resulted from it.In contrast,inter-annual climate change is the primary cause of grassland degradation,as it influenced 55.70% of degraded grassland.These results could shed light on the mechanisms of grassland variation caused by climate change and human activities,and they can be applied to further develop efficient measures to combat desertification in Altay Prefecture. 展开更多
关键词 grassland degradation net primary productivity climate change human activities Altay Prefecture
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Applications of the Kinetic Formulation for Scalar Conservation Laws with a Zero-Flux Type Boundary Condition
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作者 Zhigang WANG Yachun LI 《Chinese Annals of Mathematics,Series B》 SCIE CSCD 2012年第3期351-366,共16页
The authors are concerned with a zero-flux type initial boundary value problem for scalar conservation laws.Firstly,a kinetic formulation of entropy solutions is established.Secondly,by using the kinetic formulation a... The authors are concerned with a zero-flux type initial boundary value problem for scalar conservation laws.Firstly,a kinetic formulation of entropy solutions is established.Secondly,by using the kinetic formulation and kinetic techniques,the uniqueness of entropy solutions is obtained.Finally,the parabolic approximation is studied and an error estimate of order η 1/3 between the entropy solution and the viscous approximate solutions is established by using kinetic techniques,where η is the size of artificial viscosity. 展开更多
关键词 Scalar conservation laws Entropy solutions Kinetic formulation Uniaueness Error estimate
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