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Time-Frequency and Nonlinear Analysis of Tidal Data Observed on the Kuroshio Path
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作者 Kenta Kirimoto 《International Journal of Modern Nonlinear Theory and Application》 2016年第4期147-159,共13页
The tidal data of Kushimoto and Uragami on flow path of Kuroshio from 2004 to 2005 are investigated and discussed by time-frequency methods and nonlinear methods in this paper. These analyzing methods based on mathema... The tidal data of Kushimoto and Uragami on flow path of Kuroshio from 2004 to 2005 are investigated and discussed by time-frequency methods and nonlinear methods in this paper. These analyzing methods based on mathematical science show us new findings about the tidal motion observed on Kuroshio flow path. On the time-frequency analysis, 12 hours component and 24 hours component swing during the period of 350 hours and 320 hours respectively. However, any remarkable differences or changes depending on Kuroshio flow path weren’t seen on the result of time-frequency analysis. On the nonlinear analysis, a periodical structure has seen on the mutual information of tidal difference data, while Kuroshio flow is stable. In addition, the mutual information showed a characteristic of randomness and irregularity, while Kuroshio flow is unstable. The important results brought us a new finding such as classification of tidal motion regardless of the flow path of Kuroshio. 展开更多
关键词 Wavelet Transform Lorenz’s Plot Mutual Information time Development PERIODICITY IRREGULARITY Classification
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The Development of Arbitration Cause Should be Marched Forward With Times
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作者 YU Xiao song 《China's Foreign Trade》 2001年第12期4-4,共1页
It’s a golden season of harvest during which it was a fine autumn weather with the pale clouds and a light breeze blowing in September in Beijing. The China International Economic and Trade Arbitration Commission and... It’s a golden season of harvest during which it was a fine autumn weather with the pale clouds and a light breeze blowing in September in Beijing. The China International Economic and Trade Arbitration Commission and China Maritime Arbitration Commission held a forum of arbitrators on 26 to 28 September 2001s dealing with arbitrate work in a beautiful landscape place, Kuan Gou, a suburb in Beijing. Mr. Yu Xiaosong, the Chair- man of China Council for Promotion of International Trade/China Chamber of International Commerce, China Intemational Economic and Trade Arbitration Commission and China Maritime Arbitration Commission, gave a talk at the forum stressed that the development of arbitration cause in China should be marched with ticccccccccmes and adapted to the fast development in the situations both of home and abroad. Mr. Yu Xaosong’s talk put forward a kind of principles for the development of the arbitration cause in China, a part of which, we publish part of it here as a reference for the arbitrate circle colleagues. 展开更多
关键词 The Development of Arbitration Cause Should be Marched Forward With times more WTO APEC
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Is it time to rethink the Alzheimer's disease drug development strategy by targeting its silent phase?
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作者 Benoit Souchet Mickael Audrain +3 位作者 Baptiste Billoir Laurent Lecanu Satoru Tada Jérome Braudeau 《Neural Regeneration Research》 SCIE CAS CSCD 2018年第2期224-225,共2页
Alzheimer's disease (AD) is the most frequent cause of dementia in the western world. In clinical terms, AD is characterized by progres- sive cognitive decline that usually begins with memory impairment. As the dis... Alzheimer's disease (AD) is the most frequent cause of dementia in the western world. In clinical terms, AD is characterized by progres- sive cognitive decline that usually begins with memory impairment. As the disease progresses, AD inevitably affects all intellectual functions including executive functions, leading to complete dependence for basic activities of daily life and premature death. 展开更多
关键词 AD Is it time to rethink the Alzheimer’s disease drug development strategy by targeting its silent phase
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Viruses and autism: A Bi-mutual cause and effect
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作者 Mohammed Al-Beltagi Nermin Kamal Saeed +3 位作者 Reem Elbeltagi Adel Salah Bediwy Syed A Saboor Aftab Rawan Alhawamdeh 《World Journal of Virology》 2023年第3期172-192,共21页
Autism spectrum disorder(ASD)is a group of heterogeneous,multi-factorial,neurodevelopmental disorders resulting from genetic and environmental factors interplay.Infection is a significant trigger of autism,especially ... Autism spectrum disorder(ASD)is a group of heterogeneous,multi-factorial,neurodevelopmental disorders resulting from genetic and environmental factors interplay.Infection is a significant trigger of autism,especially during the critical developmental period.There is a strong interplay between the viral infection as a trigger and a result of ASD.We aim to highlight the mutual relationship between autism and viruses.We performed a thorough literature review and included 158 research in this review.Most of the literature agreed on the possible effects of the viral infection during the critical period of development on the risk of developing autism,especially for specific viral infections such as Rubella,Cytomegalovirus,Herpes Simplex virus,Varicella Zoster Virus,Influenza virus,Zika virus,and severe acute respiratory syndrome coronavirus 2.Viral infection directly infects the brain,triggers immune activation,induces epigenetic changes,and raises the risks of having a child with autism.At the same time,there is some evidence of increased risk of infection,including viral infections in children with autism,due to lots of factors.There is an increased risk of developing autism with a specific viral infection during the early developmental period and an increased risk of viral infections in children with autism.In addition,children with autism are at increased risk of infection,including viruses.Every effort should be made to prevent maternal and early-life infections and reduce the risk of autism.Immune modulation of children with autism should be considered to reduce the risk of infection. 展开更多
关键词 AUTISM Children Rubella Cytomegalovirus Herpes simplex virus Influenza virus Zika virus SARS-CoV-2 COVID-19 Viral infection Core Tip:There is a mutual relationship between viral infections and autism.There is an increased risk of developing autism when contracting a viral infection during pregnancy or early postnatal life during the critical period of brain development.At the same time children with autism have many co-morbidities that expose them to more risk of contracting infections including viruses.Therefore every effort should be made to prevent infections especially during this critical period of neurodevelopment.Parents should also be educated about the importance of vaccination and immune modulation in children with autism to avoid further infections.
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A Process-Based Model for Simulating Phasic Developmentand Phenology in Rice 被引量:3
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作者 MENG Ya-li, CAO Wei-xing, ZHOU Zhi-guo and LIU Xin-wei(Nanjing Agricultural University/Key Laboratory of Crop Growth Regulation, Ministry of Agriculture, Nanjing 210095 , P.R. China) 《Agricultural Sciences in China》 CAS CSCD 2003年第11期1277-1284,共8页
A simulation model for phasic and phenological development of rice was developed using the scale of physiological development time, based on the ecophysiological development processes. The interaction of daily thermal... A simulation model for phasic and phenological development of rice was developed using the scale of physiological development time, based on the ecophysiological development processes. The interaction of daily thermal effectiveness, photoperiod effectiveness and intrinsic earliness(before heading), and basic filling duration factor(after heading)determined the daily physiological effectiveness, which accumulated to get physiological development time. The Beta and quadratic functions were used to describe daily thermal and photoperiod effectiveness, respectively. Five specific genetic parameters were added to adjust the genotypic differences in rice development so that all different varieties could reach the same physiological development time at a given development stage. The stages of seedling emergence, panicle initiation, heading, and maturity were validated using sowing dates under different ecological environments, with the RMSE of 1. 47, 5. 10, 4.58 and 3.37 days, respectively. The results showed that the model was not only explanatory and systematic but also accurate and applicable. 展开更多
关键词 RICE Phasic development PHENOLOGY Physiological development time Simulation model PREDICTION
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Multi-segment and Multi-ply Overlapping Process of Multi Coupled Activities Based on Valid Information Evolution 被引量:1
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作者 WANG Zhiliang WANG Yunxia QIU Shenghai 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2013年第1期176-188,共13页
Complex product development will inevitably face the design planning of the multi-coupled activities, and overlapping these activities could potentially reduce product development time, but there is a risk of the addi... Complex product development will inevitably face the design planning of the multi-coupled activities, and overlapping these activities could potentially reduce product development time, but there is a risk of the additional cost. Although the downstream task information dependence to the upstream task is already considered in the current researches, but the design process overall iteration caused by the information interdependence between activities is hardly discussed; especially the impact on the design process' overall iteration from the valid information accumulation process. Secondly, most studies only focus on the single overlapping process of two activities, rarely take multi-segment and multi-ply overlapping process of multi coupled activities into account; especially the inherent link between product development time and cost which originates from the overlapping process of multi coupled activities. For the purpose of solving the above problems, as to the insufficiency of the accumulated valid information in overlapping process, the function of the valid information evolution (VIE) degree is constructed. Stochastic process theory is used to describe the design information exchange and the valid information accumulation in the overlapping segment, and then the planning models of the single overlapping segment are built. On these bases, by analyzing overlapping processes and overlapping features of multi-coupling activities, multi-segment and multi-ply overlapping planning models are built; by sorting overlapping processes and analyzing the construction of these planning models, two conclusions are obtained: (1) As to multi-segment and multi-ply overlapping of multi coupled activities, the total decrement of the task set development time is the sum of the time decrement caused by basic overlapping segments, and minus the sum of the time increment caused by multiple overlapping segments; (2) the total increment of development cost is the sum of the cost increment caused by all overlapping process. And then, based on overlapping degree analysis of these planning models, by the V1E degree function, the four lemmas theory proofs are represented, and two propositions are finally proved: (1) The multi-ply overlapping of the multi coupled activities will weaken the basic overlapping effect on the development cycle time reduction (2) Overlapping the multi coupled activities will decrease product development cycle, but increase product development cost. And there is trade-off between development time and cost. And so, two methods are given to slacken and eliminate multi-ply overlapping effects. At last, an example about a vehicle upper subsystem design illustrates the application of the proposed models; compared with a sequential execution pattern, the decreasing of development cycle (22%) and the increasing of development cost (3%) show the validity of the method in the example The proposed research not only lays a theoretical foundation for correctly planning complex product development process, but also provides specific and effective operation methods for overlapping multi coupled activities. 展开更多
关键词 multi coupled activities valid information evolution multi-segment multi-ply overlapping development time and cost trade-ofl iteration
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Root microbiota shift in rice correlates with resident time in the field and developmental stage 被引量:34
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作者 Jingying Zhang Na Zhang +12 位作者 Yong-Xin Liu Xiaoning Zhang Bin Hu Yuan Qin Haoran Xu Hui Wang Xiaoxuan Guo Jingmei Qian Wei Wang Pengfan Zhang Tao Jin Chengcai Chu Yang Bai 《Science China(Life Sciences)》 SCIE CAS CSCD 2018年第6期613-621,共9页
Land plants in natural soil form intimate relationships with the diverse root bacterial microbiota. A growing body of evidence shows that these microbes are important for plant growth and health. Root microbiota compo... Land plants in natural soil form intimate relationships with the diverse root bacterial microbiota. A growing body of evidence shows that these microbes are important for plant growth and health. Root microbiota composition has been widely studied in several model plants and crops; however, little is known about how root microbiota vary throughout the plant's life cycle under field conditions. We performed longitudinal dense sampling in field trials to track the time-series shift of the root microbiota from two representative rice cultivars in two separate locations in China. We found that the rice root microbiota varied dramatically during the vegetative stages and stabilized from the beginning of the reproductive stage, after which the root microbiota underwent relatively minor changes until rice ripening. Notably, both rice genotype and geographical location influenced the patterns of root microbiota shift that occurred during plant growth. The relative abundance of Deltaproteobacteria in roots significantly increased overtime throughout the entire life cycle of rice, while that of Betaproteobacteria, Firmicutes, and Gammaproteobacteria decreased. By a machine learning approach, we identified biomarker taxa and established a model to correlate root microbiota with rice resident time in the field(e.g., Nitrospira accumulated from 5 weeks/tillering in field-grown rice). Our work provides insights into the process of rice root microbiota establishment. 展开更多
关键词 rice root microbiota time-series shift biomarker taxa residence time in the field developmental stages modeling machine learning
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Estimating temperature-dependent developmental rates of potato tuberworm, Phthorimaea operculella (Lepidoptera: Gelechiidae)
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作者 Ali Golizadeh Myron P. Zalucki 《Insect Science》 SCIE CAS CSCD 2012年第5期609-620,共12页
The potato tuberworm, Phthorimaea operculella (Zeller) (Lepidoptera: Gelechiidae), is the most destructive pest of potato, Solanum tuberosum L. (Solanaceae), in tropical and subtropical regions in both field an... The potato tuberworm, Phthorimaea operculella (Zeller) (Lepidoptera: Gelechiidae), is the most destructive pest of potato, Solanum tuberosum L. (Solanaceae), in tropical and subtropical regions in both field and storeroom situations. The modeling of temperature-dependent development can be useful in forecasting occurrence and population dynamics of the pests. Published developmental parameters for this pest vary greatly for many reasons. We determined temperature-dependent development ofP operculella at seven constant temperatures (16, 20, 24, 28, 32, 34 and 36℃). Developmental period of whole immature stage (egg to the end of the pupal stage) varied from 75.5 days at 16℃ to 17 days at 32℃ The population failed to survive at 36℃. The observed data was modeled to determine mathematical functions for simulating P operculella development in each stage of development and overall. Two linear models, ordinary linear regression and the Ikemoto linear model were used to describe the relationship between temperature and de- velopment rate of the different stages ofP. operculella and estimating the thermal constant and lower temperature threshold. The lower temperature threshold (t) and thermal constant (k) of whole immature stage were estimated to be 11.6~C and 338.5 DD by Ikemoto linear model, and the estimated parameters were not substantially different with those estimated by ordinary linear models. Different models provided a better fit to the various develop- mental stages. Of the eleven nonlinear models fitted, the Beriere-1, Logan-6 and Lactin-1 model was found to be the best for modeling development rate of egg, larva and pupa of P. operculella, respectively. Phenological models based on these findings can be part of a decision-support tool to improve the efficiency of pest management programs. 展开更多
关键词 development time linear model MODELING nonlinear model Phthorimaeaoperculella thermal characteristics
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The receptor tyrosine kinase torso regulates ecdysone homeostasis to control developmental tinning in Bombyx mori
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作者 Zhong-Jie Zhang Xiao-Jing Liu +2 位作者 Ye Yu Fang-Ying Yang Kai Li 《Insect Science》 SCIE CAS CSCD 2021年第6期1582-1590,共9页
Insect growth and development are precisely controlled by hormone homeostasis.The prothoracicotropic hormone(PTTH)receptor,Torso,is a member of the receptor tyrosine kinase family in insects.Activation of Torso by PTT... Insect growth and development are precisely controlled by hormone homeostasis.The prothoracicotropic hormone(PTTH)receptor,Torso,is a member of the receptor tyrosine kinase family in insects.Activation of Torso by PTTH triggers biosynthesis and release of the steroid hormone in the prothoracic gland(PG).Although numbers of genes functioning in steroid hormone synthesis and metabolism have been identified in insects,the PTTH transduction pathway via its receptor Torso is poorly understood.In the current study,we describe a loss-of-function analysis of Torso in the silkworm,Bombyx mori,by targeted gene disruption using the transgenic CRISPR/Cas9(clustered regularly interspaced short palindromic repeats/RNA-guided Cas9 nucleases)system.Depletion of B.mori Torso(BmTorso)did not eventually affect larval ecdysis and metamorphosis processes.Instead,BmTorso deficiency resulted in significant extension of developing time during larval and pupal stages with increased pupa and cocoon sizes.The eedysteriod titers in the hemolymph of BmTorso mutants sharpy declined.Transcriptional levels of genes involved in ecdysone biosynthesis and eedysteroid signaling pathways were significantly reduced in BniTorso-defic'iQnt animals.Additionally,RNA-Seq analysis revealed that genes involved in the longevity pathway and protein processing in the endoplasmic reticulum pathway were affected after BmTorso deletion.These results indicate that Torso is critical for maintaining steroid hormone homeostasis in insects. 展开更多
关键词 Bombyx mori CRISPR/Cas9 developmental timing TORSO
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Chinese Buddhism's Philosophical Features and Trend of Development in Modern Times
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作者 LAI Yonghai 《The Voice of Dharma》 2021年第2期20-28,共9页
Chinese Buddhism, one of the most important branches of Buddhism, has exerted tremendous influence on all aspects of the Chinese society. The reason that Buddhism in the Han area in Chinese history universally adopted... Chinese Buddhism, one of the most important branches of Buddhism, has exerted tremendous influence on all aspects of the Chinese society. The reason that Buddhism in the Han area in Chinese history universally adopted Mahayana independent of man’s will was that the Mahayana spirit of altruism, benefiting society, compassion, and liberation of the world, in comparison with Hinayana Buddhism’s emphasis of benefiting and liberating the self, was more compatible with the demands of the development of Chinese society at the time. It could be said that the spirit of Mahayana Bodhisattva Path that emphasizes helping living beings and benefiting the world, and the Chan philosophy that focuses on the nature of the mind and pays attention to real life, are indeed the philosophical features of Chinese Buddhism. Chinese Buddhism(the Chan school in particular) has been greatly influenced by the Confucian thoughts, which have been the mainstream ideology of China. Its success in fusing with and absorbing the Confucian thoughts is a paragon even in the development history of human culture. Humanistic Buddhism(renjian fojiao 人间佛教) in modern times inherited and promoted the tradition of Chan Buddhism to stress real life, and an important aspect of Venerable Master Taixu’s(太虚) reform is to turn the Buddha-oriented tradition of Buddhism to the human-oriented. 展开更多
关键词 Chinese Buddhism Confucian spirit philosophical features trend of development in modern times
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Enlightenment From the Development of Ancient City Planning in China in the Ancient Times
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作者 Shen Yahong Lectuer,Huanan Polytechics 《China City Planning Review》 1992年第1期65-75,共11页
China is among the first countries in the world in developing the science of urban planning,and has evolved her own unique system.Through investigating the structural features of the plan-ning system,the laws governin... China is among the first countries in the world in developing the science of urban planning,and has evolved her own unique system.Through investigating the structural features of the plan-ning system,the laws governing its development and the causes of the rise and fall of the ancientplanning system,this article attempts to propose some insights useful to the establishment and de-velopment of the modern city planning in China. 展开更多
关键词 Enlightenment From the Development of Ancient City Planning in China in the Ancient times
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Time development of surface enhanced Raman intensities of the adsorbed pyrazine molecules on the silver electrode as the applied voltage varies
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作者 WU,Guo-Zhen HUANG,Yi Institute of Chemistry,Chinese Academy of Sciences,Beijing 100080 《Chinese Journal of Chemistry》 SCIE CAS CSCD 1993年第5期395-400,共8页
In this work,the time development of surface enhanced Raman intensities of the vibrational modes involving the ring skeleton and the C—H motions of the pyrazine molecule as the applied voltage on the silver electrode... In this work,the time development of surface enhanced Raman intensities of the vibrational modes involving the ring skeleton and the C—H motions of the pyrazine molecule as the applied voltage on the silver electrode is shifted between -0.2 V and -0.5 V (vs.saturated calomel electrode)is reported.The observation shows that there are two processes of enhancement involved during this shift of applied voltage.One is vibrational mode dependent while the other is not.The detailed behavior of these two processes of enhancement is discussed along with the retarded response of the Helmholtz double layer structure to the change of the applied voltage on the electrode. 展开更多
关键词 time development of surface enhanced Raman intensities of the adsorbed pyrazine molecules on the silver electrode as the applied voltage varies SERS
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Bract suppression regulated by the miR156/529-SPLs-NL1-PLA1 module is required for the transition from vegetative to reproductive branching in rice 被引量:10
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作者 Lei Wang Luchang Ming +15 位作者 Keyan Liao Chunjiao Xia Shengyuan Sun Yu Chang Hongkai Wang Debao Fu Conghao Xu Zhengji Wang Xu Li Weibo Xie Yidan Ouyang Qinglu Zhang Xianghua Li Qinghua Zhang Jinghua Xiao Qifa Zhang 《Molecular Plant》 SCIE CAS CSCD 2021年第7期1168-1184,共17页
Reproductive transition of grasses is characterized by switching the pattern of lateral branches,featuring the suppression of outgrowth of the subtending leaves(bracts)and rapid formation of higher-order branches in t... Reproductive transition of grasses is characterized by switching the pattern of lateral branches,featuring the suppression of outgrowth of the subtending leaves(bracts)and rapid formation of higher-order branches in the inflorescence(panicle).However,the molecular mechanisms underlying such changes remain largely unknown.Here,we show that bract suppression is required for the reproductive branching in rice.We identified a pathway involving the intrinsic time ruler microRNAI56/529,their targets SQUAMOSA PROMOTER BINDING PROTEIN LIKE(SPL)genes,NECK LEAF1(NL1),and PLASTOCHRON1(PLA1),which regulates the bract outgrowth and thus affects the pattern switch between vegetative and reproductive branching.Suppression of the bract results in global reprogramming of transcriptome and chromatin accessibility following the reproductive transition,while these processes are largely dysregu-lated in the mutants of these genes.These discoveries contribute to our understanding of the dynamic plant architecture and provide novel insights for improving crop yields. 展开更多
关键词 GRASS plant architecture developmental timing lateral branch bract suppression
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Development of Chrysomya megacephala at constant temperatures within its colony range in Yangtze River Delta region of China 被引量:4
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作者 Yingna Zhang Yu Wang +2 位作者 Lijun Yang Luyang Tao Jiangfeng Wang 《Forensic Sciences Research》 2018年第1期74-82,共9页
Chrysomya megacephala (Fabricius,1794) is the most abundant and predominant species which arrives and colonizes a cadaver first in most parts of China.Therefore,its growth and development patterns have great implicati... Chrysomya megacephala (Fabricius,1794) is the most abundant and predominant species which arrives and colonizes a cadaver first in most parts of China.Therefore,its growth and development patterns have great implications in the estimation of the minimum postmortem interval (PMImin).In this study,C megacephala was collected from the Yangtze River Delta region and reared at seven constant temperatures ranging from 16 ℃ to 34 ℃.The developmental duration and accumulated degree hours,larval body length and morphological changes of C.megacephala were examined.Furthermore,we constructed three developmental models,isomorphen diagram,isomegalen diagram and thermal summation model,which can be used for estimating PMImin.The developmental durations of C.megacephala at 16 ℃,19 ℃,22 ℃,25 ℃,28 ℃,31 ℃ and 34 ℃ are (794.8 ± 14.7),(533.2 ± 10.1),(377.8 ± 16.8),(280.8 ± 15.1),(218.9 ± 8.5),(190.8 ± 10.1) and (171.8 ± 6.8) h,respectively.The developmental threshold temperature D0 is (11.41 ± 0.32) ℃,and the thermal summation constant K is (3 418.7 ± 137.0) degree hours.Regression analysis was conducted to obtain equations of the variation in larval body length with time after hatching,and variation in time after hatching with body length.Moreover,our study divides the intra-puparial morphological changes of C.megacephala into 11 sub-stages,and provides the time range experienced by each sub-stage.The results of this study provide fundamental development data for the use of C.megacephala in PMImin estimations. 展开更多
关键词 Forensic science forensic entomology oriental latrine fly development time isomorphen/isomegalen diagram thermal summation model intra-puparial development
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Co-infection of Wolbachia and Spiroplasma in spider mite Tetranychus truncatus increases male fitness 被引量:1
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作者 Kang Xie Yi-Jia Lu +2 位作者 Kun Yang Shi-Mei Huo Xiao-Yue Hong 《Insect Science》 SCIE CAS CSCD 2020年第5期921-937,共17页
Wolbachia and Spiroplasma are intracellular bacteria that are of great interest to entomologists,because of their ability to alter insect host biology in multiple ways.In the spider mite Tetranychus truncatus,co-infec... Wolbachia and Spiroplasma are intracellular bacteria that are of great interest to entomologists,because of their ability to alter insect host biology in multiple ways.In the spider mite Tetranychus truncatus,co-infection of Wolbachia and Spiroplasma can induce cytoplasmic incompatibility(CI)and fitness costs;however,lttle is known about the effect of co-infection at the genetic level and the molecular mechanisms underlying CI.In this study,we explored the influence of the two symbionts on male mite host fitness and used RNA sequencing to generate the transcriptomes of T truncatus with four different types of infection.In total,we found symbiont-infected lines had a higher hatch proportion than the uninfected line,and the development time of the uninfected line was longer than that of the other lines.Co-infection changed the expression of many genes related to digestion detoxification,reproduction,immunity and oxidation reduction.Our results indicate that co-infection of Wolbachia and Spiroplasma confers multiple effects on their hosts,and helps iluminate the complex interactions between endosymbionts and arthropods. 展开更多
关键词 CO-INFECTION development time SPIROPLASMA Tetranychus truncatus tran-scriptome WOLBACHIA
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Inter-annual variations in vegetation and their response to climatic factors in the upper catchments of the Yellow River from 2000 to 2010 被引量:20
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作者 CAO Ran JIANG Weiguo +3 位作者 YUAN Lihua WANG Wenjie LV Zhongliang CHEN Zheng 《Journal of Geographical Sciences》 SCIE CSCD 2014年第6期963-979,共17页
To understand the variations in vegetation and their correlation with climate factors in the upper catchments of the Yellow River, China, Normalized Difference Vegetation Index(NDVI) time series data from 2000 to 20... To understand the variations in vegetation and their correlation with climate factors in the upper catchments of the Yellow River, China, Normalized Difference Vegetation Index(NDVI) time series data from 2000 to 2010 were collected based on the MOD13Q1 product. The coefficient of variation, Theil–Sen median trend analysis and the Mann–Kendall test were combined to investigate the volatility characteristic and trend characteristic of the vegetation. Climate data sets were then used to analyze the correlation between variations in vegetation and climate change. In terms of the temporal variations, the vegetation in this study area improved slightly from 2000 to 2010, although the volatility characteristic was larger in 2000–2005 than in 2006–2010. In terms of the spatial variation, vegetation which is relatively stable and has a significantly increasing trend accounts for the largest part of the study area. Its spatial distribution is highly correlated with altitude, which ranges from about 2000 to 3000 m in this area. Highly fluctuating vegetation and vegetation which showed a significantly decreasing trend were mostly distributed around the reservoirs and in the reaches of the river with hydropower developments. Vegetation with a relatively stable and significantly decreasing trend and vegetation with a highly fluctuating and significantly increasing trend are widely dispersed. With respect to the response of vegetation to climate change, about 20–30% of the vegetation has a significant correlation with climatic factors and the correlations in most areas are positive: regions with precipitation as the key influencing factor account for more than 10% of the area; regions with temperature as the key influencing factor account for less than 10% of the area; and regions with precipitation and temperature as the key influencing factors together account for about 5% of the total area. More than 70% of the vegetation has an insignificant correlation with climatic factors. 展开更多
关键词 correlation analysis coefficient of variation hydropower development Mann–Kendall test NDVI time series data Theil–Sen median trend analysis Yellow River China
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