On December 21, 20：10, a stray dog consecutively attacked 10 people in Lengshui Village, Ningyuan County, Yongzhou City, Hunan Province, China. The dog was killed by the local CDC staff and vicinity villager, its bra...On December 21, 20：10, a stray dog consecutively attacked 10 people in Lengshui Village, Ningyuan County, Yongzhou City, Hunan Province, China. The dog was killed by the local CDC staff and vicinity villager, its brain tissue sample was taken within 24 h. The epidemic focus was disinfected and the injured people received post exposure prophylaxis （PEP）. Pathogens were detected in the tissue sample by the provincial CDC. The immunity and safety of rabies vaccine were assayed after PEP, the injured people were regularly followed up in the following 2 y and 6 mon.展开更多
Continuous monoculture problems, or replanting diseases, are one of the key factors affecting productivity and quality of Chinese medicinal plants. The underlying mechanism is still being explored. Most of the studies...Continuous monoculture problems, or replanting diseases, are one of the key factors affecting productivity and quality of Chinese medicinal plants. The underlying mechanism is still being explored. Most of the studies on continuous monoculture ofRehmannia glutinosa L. are focused on plant nutritional physiology, root exudate, and its autotoxieity. However, the changes in the diversity of microflora in the rhizosphere mediated by the continuous monoculture pattern have been remained unknown. In this study, terminal restriction fragment length polymorphism （T-RFLP） technique was used for fingerprinting fungal diversity in the rhizosphere soil sampled from the fields ofR. glutinosa monocultured for 1 and 2 yr. The results showed that the structure of fungal community in consecutively moncultured rhizosphere soil was different from that in control soil （no cropping soil）, and varied with the consecutive monoeulture years （1 and 2 yr）. The comprehensive evaluation index （D） of fungal community estimated by principal component analysis of fragment number, peak area, Shannon-Weiner index, and Margalef index was higher in 1 yr monoculture soil than that in 2 yr monoculture soil, suggesting that consecutive monoculture of R. glutinosa could be a causative agent to decrease the diversity of fungal community in the rhizosphere soil.展开更多
155⁃year⁃old Hilde Dosogne of Belgium recently set a new world record for most consecutive(连续的)marathons after running 366 full marathons(over 15,000 km)in 2024.2 On May 30,2024,Hilde Dosogne had already broken the...155⁃year⁃old Hilde Dosogne of Belgium recently set a new world record for most consecutive(连续的)marathons after running 366 full marathons(over 15,000 km)in 2024.2 On May 30,2024,Hilde Dosogne had already broken the women's world record for most consecutive marathons—150,set by Erchana Murray⁃Bartlett—but she didn't stop running until December 31st,when she recorded her 366th consecutive full marathon of the year.As you can imagine,running 42.195 km per day,every day,for a year is incredibly taxing for the body,but while Hilde had to overcome tiredness and bursitis(滑囊炎),she claimed that the mental stress of having to show up at the starting line every day was her most difficult challenge.展开更多
Consecutive stresses,such as initial submergence during germination followed by water deficit during the seedling stage,pose significant challenges to direct-seeded rice cultivation.By Linkage disequilibrium analysis,...Consecutive stresses,such as initial submergence during germination followed by water deficit during the seedling stage,pose significant challenges to direct-seeded rice cultivation.By Linkage disequilibrium analysis,Sub1 and Dro1(Δbp:10 Mb),as well as Sub1 and TPP7(Δbp:6 Mb)were identified to exhibit long-range linkage disequilibrium(LRLD).Meta-QTL analysis further revealed that Sub1 and TPP7 co-segregated for tolerance to submergence at the germination and seedling stages.Based on this,we hypothesized that LRLD might influence plant responses to consecutive stresses.To test this hypothesis,we developed a structured recombinant inbred line population from a cross between Bhalum 2 and Nagina 22,with alleles(Sub1 and TPP7)in linkage equilibrium.Mendelian randomization analysis validated that the parental alleles,rather than the recombinant alleles of Sub1 and TPP7,significantly influenced 13 out of 41 traits under consecutive stress conditions.Additionally,16 minor additive effect QTLs were detected between the genomic regions,spanning Sub1 and TPP7 for various traits.A single allele difference between these genomic regions enhanced crown root number,root dry weight,and specific root area by 11.45%,15.69%,and 33.15%,respectively,under flooded germination conditions.Candidate gene analysis identified WAK79 and MRLK59 as regulators of stress responses during flooded germination,recovery,and subsequent water deficit conditions.These findings highlight the critical role of parental allele combinations and genomic regions between Sub1 and TPP7 in regulating the stress responses under consecutive stresses.Favourable haplotypes derived from these alleles can be utilized to improve stress resilience in direct-seeded rice.展开更多
Transition-metal-catalyzed tandem cross-coupling reactions can rapidly construct complex molecules,but they often suffer from site-and regio-selectivity issues.Here,we designed a novel nickel-catalyzed three-component...Transition-metal-catalyzed tandem cross-coupling reactions can rapidly construct complex molecules,but they often suffer from site-and regio-selectivity issues.Here,we designed a novel nickel-catalyzed three-component cross-electrophile coupling(cXEC)platform that enables access to valuable gem-difluoroalkenes.This multicomponent reaction proceeds through a chemoselective alkenylation of aryl halides,followed by alkylation of α-(trifluoromethyl)styrenes,providing a streamlined pathway towards this kind of building blocks.展开更多
The multiscale variability in summer extreme persistent precipitation(SEPP)in China from 1961 to 2020 was investigated via three extreme precipitation indices:consecutive wet days,total precipitation amount,and daily ...The multiscale variability in summer extreme persistent precipitation(SEPP)in China from 1961 to 2020 was investigated via three extreme precipitation indices:consecutive wet days,total precipitation amount,and daily precipitation intensity.The relationships between precursory and concurrent global oceanic modes and SEPP were identified via a generalized linear model(GLM).The influence of oceanic modes on SEPP was finally investigated via numerical simulations.The results revealed that the climatological SEPP(≥14 days)mainly appears across the Tibetan Plateau,Yunnan–Guizhou Plateau,and South China coast.The first EOF mode for all three indices showed strong signals over the Yangtze River.Further analysis via the GLM suggested that the positive phases of the tropical North Atlantic(TNA)in autumn,ENSO in winter,the Indian Ocean Basin(IOB)in spring,and the western North Pacific(WNP)in summer emerged as the most effective precursory factors of SEPP,which could serve as preceding signals for future predictions,contributing 30.2%,36.4%,38.0%,and 55.6%,respectively,to the GLM.Sensitivity experiments revealed that SST forcing in all four seasons contributes to SEPP over China,whereas the winter and summer SST warming over the Pacific and Indian Ocean(IO)contributes the most.Diagnosis of the hydrological cycle suggested that water vapor advection predominantly originates from the western Pacific and IO in summer,driven by the strengthened subtropical high and Asian summer monsoon(ASM).The enhanced vertical water vapor transport is attributed to stronger upward motion across all four seasons.These findings are helpful for better understanding SEPP variabilities and their prediction under SST warming.展开更多
Dear Editor,Brown syndrome is an ocular motility disorder characterized by restriction of elevation in adduction combined with a positive forced duction test and minimal or no superior oblique(SO)overaction[1].Other f...Dear Editor,Brown syndrome is an ocular motility disorder characterized by restriction of elevation in adduction combined with a positive forced duction test and minimal or no superior oblique(SO)overaction[1].Other features include V-pattern horizontal deviation and palpebral fissure widening while adduction[1].展开更多
Spring consecutive rainfall events(CREs) are key triggers of geological hazards in the Three Gorges Reservoir area(TGR), China. However, previous projections of CREs based on the direct outputs of global climate model...Spring consecutive rainfall events(CREs) are key triggers of geological hazards in the Three Gorges Reservoir area(TGR), China. However, previous projections of CREs based on the direct outputs of global climate models(GCMs) are subject to considerable uncertainties, largely caused by their coarse resolution. This study applies a triple-nested WRF(Weather Research and Forecasting) model dynamical downscaling, driven by a GCM, MIROC6(Model for Interdisciplinary Research on Climate, version 6), to improve the historical simulation and reduce the uncertainties in the future projection of CREs in the TGR. Results indicate that WRF has better performances in reproducing the observed rainfall in terms of the daily probability distribution, monthly evolution and duration of rainfall events, demonstrating the ability of WRF in simulating CREs. Thus, the triple-nested WRF is applied to project the future changes of CREs under the middle-of-the-road and fossil-fueled development scenarios. It is indicated that light and moderate rainfall and the duration of continuous rainfall spells will decrease in the TGR, leading to a decrease in the frequency of CREs. Meanwhile, the duration, rainfall amount, and intensity of CREs is projected to regional increase in the central-west TGR. These results are inconsistent with the raw projection of MIROC6. Observational diagnosis implies that CREs are mainly contributed by the vertical moisture advection. Such a synoptic contribution is captured well by WRF, which is not the case in MIROC6,indicating larger uncertainties in the CREs projected by MIROC6.展开更多
Dicarboxylic acids have a wide range of applications in the polymer industry to construct valuable materials.Photocatalysis has recently emerged as an efficient and sustainable strategy to generate dicarboxylic acids....Dicarboxylic acids have a wide range of applications in the polymer industry to construct valuable materials.Photocatalysis has recently emerged as an efficient and sustainable strategy to generate dicarboxylic acids.However,photocatalytic dicarboxylation with CO_(2) is mainly limited to unsaturated bonds,and the dicarboxylation of C-C single bonds still remains a challenge.Herein,we report a photocatalytic dicarboxylation of C-C single bonds in strained rings with CO_(2) units via consecutive photo-induced electron transfer(ConPET).It is also the first photocatalytic reductive ring-opening reaction of cyclobutanes.Notably,this transition-metal-free protocol exhibits good functional group tolerance,broad substrate scope,facile scalability,and easy product derivatizations.Moreover,diacids can easily be derivatized to mainchain liquid crystalline polyesters.展开更多
For some important object recognition applications such as intelligent robots and unmanned driving, images are collected on a consecutive basis and associated among themselves, besides, the scenes have steady prior fe...For some important object recognition applications such as intelligent robots and unmanned driving, images are collected on a consecutive basis and associated among themselves, besides, the scenes have steady prior features. Yet existing technologies do not take full advantage of this information. In order to take object recognition further than existing algorithms in the above application, an object recognition method that fuses temporal sequence with scene priori information is proposed. This method first employs YOLOv3 as the basic algorithm to recognize objects in single-frame images, then the DeepSort algorithm to establish association among potential objects recognized in images of different moments, and finally the confidence fusion method and temporal boundary processing method designed herein to fuse, at the decision level, temporal sequence information with scene priori information. Experiments using public datasets and self-built industrial scene datasets show that due to the expansion of information sources, the quality of single-frame images has less impact on the recognition results, whereby the object recognition is greatly improved. It is presented herein as a widely applicable framework for the fusion of information under multiple classes. All the object recognition algorithms that output object class, location information and recognition confidence at the same time can be integrated into this information fusion framework to improve performance.展开更多
According to the daily precipitation data in artificial precipitation season during May to September from 1961 to 2008 in Liaoning Province,the maximum consecutive precipitation in the artificial precipitation test ar...According to the daily precipitation data in artificial precipitation season during May to September from 1961 to 2008 in Liaoning Province,the maximum consecutive precipitation in the artificial precipitation test area is studied based on the maximum consecutive precipitation from May to September in 48 years.The results shows that the period of maximum consecutive precipitation in each month is different,and the variance trends of maximum consecutive precipitation in May,July,August and September are decreasing,while the variance trend of maximum consecutive precipitation in June is increasing.展开更多
Hollow titanium silicalite （HTS） molecular sieve has been synthesized, and information on its structure, physico- chemical characterization, as well as surface property was investigated by a host of analytical metho...Hollow titanium silicalite （HTS） molecular sieve has been synthesized, and information on its structure, physico- chemical characterization, as well as surface property was investigated by a host of analytical methods, such as XRF, XRD, low-temperature N2 adsorption/desorption, TEM, FT-IR, UV-Vis, 29Si MAS NIVIR, and XPS techniques. The characterization results suggest that HTS zeolite has a special hollow crystal structure and its mesopore volume is larger than that of TS-1 zeolite. The titanium species in this zeolite are composed of the framework tetrahedral Ti （IV） ions and extra-framework octahedral Ti （IV） ions, which tend to disperse into its bulk phase. This zeolite material also has been applied to catalyze the cyclohexanone oxidation process, and the products are not completely consistent with those results obtained by using TS-1 zeolite, which might be caused by their difference in pore structure and pore volume, especially the mesopore volume. Cy- clohexanone oxidation catalyzed by HTS zeolite is a representative consecutive reaction, the main target products of which are e-caprolactone, 6-hydroxyhexanoic acid and adipic acid. The effect of H202/cyclohexanone mole ratio on the cyclohexa- none conversion, the total target product selectivity, the distribution of three target products selectivity and their variations along with reaction time is also researched and analyzed, which indicate that HTS zeolite shows a high performance for the Baeyer-Villiger reaction of cyclohexanone and catalytic oxidation of 6-hydroxyhexanoic acid under mild conditions, and the quantity of active surface titanium species as well as the pore structure and mesopore volume controlling the mass diffusion rate are the key factors determining the catalytic activity of HTS zeolite and product selectivity.展开更多
Based on daily surface climate data and weather phenomenon data, the spatial and temporal distribution and trend on the number of consecutive days of severe weathers were analyzed in China during 1959-2014. The result...Based on daily surface climate data and weather phenomenon data, the spatial and temporal distribution and trend on the number of consecutive days of severe weathers were analyzed in China during 1959-2014. The results indicate that the number of consecutive days for hot weathers increased at a rate of 0.1 day per decade in China as a whole, while that for cold weathers, snowfall weathers, thunderstorm weathers and foggy weathers showed significant decreasing trends at rates of 1.4, 0.3, 0.4 and 0.4 day per decade, re- spectively. Spatially, there were more consecutive hot days and rainstorm days in southeast- ern China, and more consecutive cold days and snowfall days in northeastern China and western China. Consecutive thunderstorm days were more in southern China and south- western China, and consecutive foggy days were more in some mountain stations. Over the past 56 years, annual number of consecutive cold days decreased mainly in most parts of western China and eastern China. Consecutive thunderstorm days decreased in most parts of China. The trend of consecutive hot days, snowfall days and foggy days was not significant in most parts of China, and that of consecutive rainstorm days was not significant in almost the entire China.展开更多
Drought acutely affects economic sectors, natural habitats and communities. Understanding the past spatial and temporal patterns of drought is crucial because it facilitates the forecasting of future drought occurrenc...Drought acutely affects economic sectors, natural habitats and communities. Understanding the past spatial and temporal patterns of drought is crucial because it facilitates the forecasting of future drought occurrences and informs decision-making processes for possible adaptive measures. This is especially important in view of a changing climate. This study employed the World Meteorological Organization(WMO)-recommended standardized precipitation index(SPI) to investigate the spatial and temporal patterns of drought in Zambia from 1960 to 2016. The relationship between the occurrence of consecutive dry days(CDD; consecutive days with less than 1 mm of precipitation) and SPI was also investigated. Horizontal wind vectors at 850 hPa during the core of the rainy season(December–February)were examined to ascertain the patterns of flow during years of extreme and severe drought; and these were contrasted with the patterns of flow in 2007, which was a generally wet year. Pressure vertical velocity was also investigated. Based on the gamma distribution, SPI successfully categorized extremely dry(with a SPI value less than or equal to –2.0) years over Zambia as 1992 and 2015, a severely dry(–1.9 to –1.5) year as 1995, moderately dry(–1.4 to –1.0) years as 1972, 1980, 1987, 1999 and 2005, and 26 near normal years(–0.9 to 0.9). The occurrence of CDD was found to be strongly negatively correlated with SPI with a coefficient of –0.6. Further results suggest that, during wet years, Zambia is influenced by a clockwise circulating low-pressure zone over the south-eastern Angola, a second such zone over the northern and eastern parts, and a third over the Indian Ocean. In stark contrast, years of drought were characterized by an anti-clockwise circulating high-pressure zone over the south-western parts of Zambia,constraining precipitation activities over the country. Further, wet years were characterized by negative pressure vertical velocity anomalies, signifying ascending motion; while drought years were dominated by positive anomalies, signifying descending motion, which suppresses precipitation. These patterns can be used to forecast drought over Zambia and aid in strategic planning to limit the potential damage of drought.展开更多
The effects of higher modes and torsion have a significant impact on the seismic responses of asymmetric-plan tall buildings. A consecutive modal pushover (CMP) procedure is one of the pushover methods that have been ...The effects of higher modes and torsion have a significant impact on the seismic responses of asymmetric-plan tall buildings. A consecutive modal pushover (CMP) procedure is one of the pushover methods that have been developed to consider these effects. The aim of this paper is to modify the (CMP) analysis procedure to estimate the seismic demands of one-way asymmetric-plan tall buildings with dual systems. An analysis of 10-, 15- and 20-story asymmetric-plan buildings is carried out, and the results from the modified consecutive modal pushover (MCMP) procedure are compared with those obtained from the modal pushover analysis (MPA) procedure and the nonlinear time history analysis (NLTHA). The MCMP estimates of the seismic demands of one-way asymmetric-plan buildings demonstrate a reasonable accuracy, compared to the results obtained from the NLTHA. Furthermore, the accuracy of the MCMP procedure in the prediction of plastic hinge rotations is better than the MPA procedure. The new pushover procedure is also more accurate than the FEMA load distribution and the MPA procedure.展开更多
Importance measures in reliability systems are used to identify weak components in contributing to a proper function of the system. Traditional importance measures mainly concerned the changing value of the system rel...Importance measures in reliability systems are used to identify weak components in contributing to a proper function of the system. Traditional importance measures mainly concerned the changing value of the system reliability caused by the change of the reliability of the component, and seldom considered the joint effect of the probability distribution, improvement rate of the object component. This paper studies the rate of the system reliability upgrading with an improvement of the component reliability for the multi-state consecutive k-out-of-n system. To verify the multi-state consecutive k-out-of-n system reliability upgrading by improving one component based on its improvement rate, an increasing potential importance （IPI） and its physical meaning are described at first. Secondly, the relationship between the IPI and Birnbaum importance measures are discussed. And the IPI for some different improvement actions of the component is further discussed. Thirdly, the characteristics of the IPI are analyzed. Finally, an application to an oil pipeline system is given.展开更多
Multistage hydraulic fracturing in horizontal wells is a critical technique for developing unconventional oil and gas resources.Stress interactions among neighboring fractures cause immature fracture development.The T...Multistage hydraulic fracturing in horizontal wells is a critical technique for developing unconventional oil and gas resources.Stress interactions among neighboring fractures cause immature fracture development.The Texas two-step fracturing(TTSF)method is a new technique that aims to enhance fracture complexity and conductivity.This paper compares the fracture development of consecutive fracturing and the TTSF.The fracturing sequence in the multistage fracturing method has a significant effect on the fracture length,fracture width and injection pres sure.The consecutive fracturing results in relatively uneven fracture length and width.Certain fractures in consecutive fracturing are restrained to be closed due to the strong stress shadowing effect.In contrast,TTSF has considerable potential for alleviating the negative effects of stress interactions and producing a larger stimulated reservoir volume.展开更多
Quantized kernel least mean square(QKLMS) algorithm is an effective nonlinear adaptive online learning algorithm with good performance in constraining the growth of network size through the use of quantization for inp...Quantized kernel least mean square(QKLMS) algorithm is an effective nonlinear adaptive online learning algorithm with good performance in constraining the growth of network size through the use of quantization for input space. It can serve as a powerful tool to perform complex computing for network service and application. With the purpose of compressing the input to further improve learning performance, this article proposes a novel QKLMS with entropy-guided learning, called EQ-KLMS. Under the consecutive square entropy learning framework, the basic idea of entropy-guided learning technique is to measure the uncertainty of the input vectors used for QKLMS, and delete those data with larger uncertainty, which are insignificant or easy to cause learning errors. Then, the dataset is compressed. Consequently, by using square entropy, the learning performance of proposed EQ-KLMS is improved with high precision and low computational cost. The proposed EQ-KLMS is validated using a weather-related dataset, and the results demonstrate the desirable performance of our scheme.展开更多
This paper investigates the remote tracking control problem of Network-based Agents with communication delays existing in both forward and feedback communication channels.A networked predictive tracking controller is ...This paper investigates the remote tracking control problem of Network-based Agents with communication delays existing in both forward and feedback communication channels.A networked predictive tracking controller is proposed to compensate the negative effects caused by bilateral time-delays in a wireless network.Furthermore,the problem of consecutive data loss in the feedback channel is solved using aforementioned controller,where lateral movement perturbations are introduced.Simulations and experiments are provided for several cases,which verify the realizability and effectiveness of the proposed controller.展开更多
基金supported by the National Department Public Benefit Research Foundation(201103032)
文摘On December 21, 20：10, a stray dog consecutively attacked 10 people in Lengshui Village, Ningyuan County, Yongzhou City, Hunan Province, China. The dog was killed by the local CDC staff and vicinity villager, its brain tissue sample was taken within 24 h. The epidemic focus was disinfected and the injured people received post exposure prophylaxis （PEP）. Pathogens were detected in the tissue sample by the provincial CDC. The immunity and safety of rabies vaccine were assayed after PEP, the injured people were regularly followed up in the following 2 y and 6 mon.
基金supported by the National Natural Science Foundation of China (30772729, 30671201, and81072983)the Key Technologies R&D Programof China during the 11th Five-Year Plan period(2006BAI09B03 and 2006BAI06A12-06)
文摘Continuous monoculture problems, or replanting diseases, are one of the key factors affecting productivity and quality of Chinese medicinal plants. The underlying mechanism is still being explored. Most of the studies on continuous monoculture ofRehmannia glutinosa L. are focused on plant nutritional physiology, root exudate, and its autotoxieity. However, the changes in the diversity of microflora in the rhizosphere mediated by the continuous monoculture pattern have been remained unknown. In this study, terminal restriction fragment length polymorphism （T-RFLP） technique was used for fingerprinting fungal diversity in the rhizosphere soil sampled from the fields ofR. glutinosa monocultured for 1 and 2 yr. The results showed that the structure of fungal community in consecutively moncultured rhizosphere soil was different from that in control soil （no cropping soil）, and varied with the consecutive monoeulture years （1 and 2 yr）. The comprehensive evaluation index （D） of fungal community estimated by principal component analysis of fragment number, peak area, Shannon-Weiner index, and Margalef index was higher in 1 yr monoculture soil than that in 2 yr monoculture soil, suggesting that consecutive monoculture of R. glutinosa could be a causative agent to decrease the diversity of fungal community in the rhizosphere soil.
文摘155⁃year⁃old Hilde Dosogne of Belgium recently set a new world record for most consecutive(连续的)marathons after running 366 full marathons(over 15,000 km)in 2024.2 On May 30,2024,Hilde Dosogne had already broken the women's world record for most consecutive marathons—150,set by Erchana Murray⁃Bartlett—but she didn't stop running until December 31st,when she recorded her 366th consecutive full marathon of the year.As you can imagine,running 42.195 km per day,every day,for a year is incredibly taxing for the body,but while Hilde had to overcome tiredness and bursitis(滑囊炎),she claimed that the mental stress of having to show up at the starting line every day was her most difficult challenge.
基金supported by the Director General,Indian Council of Agricultural Research(ICAR),New Delhithe Director,ICAR-National Rice Research Institute,Cuttack.
文摘Consecutive stresses,such as initial submergence during germination followed by water deficit during the seedling stage,pose significant challenges to direct-seeded rice cultivation.By Linkage disequilibrium analysis,Sub1 and Dro1(Δbp:10 Mb),as well as Sub1 and TPP7(Δbp:6 Mb)were identified to exhibit long-range linkage disequilibrium(LRLD).Meta-QTL analysis further revealed that Sub1 and TPP7 co-segregated for tolerance to submergence at the germination and seedling stages.Based on this,we hypothesized that LRLD might influence plant responses to consecutive stresses.To test this hypothesis,we developed a structured recombinant inbred line population from a cross between Bhalum 2 and Nagina 22,with alleles(Sub1 and TPP7)in linkage equilibrium.Mendelian randomization analysis validated that the parental alleles,rather than the recombinant alleles of Sub1 and TPP7,significantly influenced 13 out of 41 traits under consecutive stress conditions.Additionally,16 minor additive effect QTLs were detected between the genomic regions,spanning Sub1 and TPP7 for various traits.A single allele difference between these genomic regions enhanced crown root number,root dry weight,and specific root area by 11.45%,15.69%,and 33.15%,respectively,under flooded germination conditions.Candidate gene analysis identified WAK79 and MRLK59 as regulators of stress responses during flooded germination,recovery,and subsequent water deficit conditions.These findings highlight the critical role of parental allele combinations and genomic regions between Sub1 and TPP7 in regulating the stress responses under consecutive stresses.Favourable haplotypes derived from these alleles can be utilized to improve stress resilience in direct-seeded rice.
基金financial support from the National Natural Science Foundation of China(Nos.22071101 and 22271147)China Postdoctoral Science Foundation(Nos.2021T140309 and 2021M691511)Natural Science Foundation of Jiangsu Province(No.BK20230771).
文摘Transition-metal-catalyzed tandem cross-coupling reactions can rapidly construct complex molecules,but they often suffer from site-and regio-selectivity issues.Here,we designed a novel nickel-catalyzed three-component cross-electrophile coupling(cXEC)platform that enables access to valuable gem-difluoroalkenes.This multicomponent reaction proceeds through a chemoselective alkenylation of aryl halides,followed by alkylation of α-(trifluoromethyl)styrenes,providing a streamlined pathway towards this kind of building blocks.
基金jointly funded by the National Natural Science Foundation of China(Grant Nos.42122035,42288101,42130605,72293604,42475179,and 42475020)the support of the Guangdong Provincial Observation and Research Station for Tropical Ocean Environment in Western Coastal Waters(GSTOEW)+2 种基金Key Laboratory of Space Ocean Remote Sensing and ApplicationCMAGDOU Joint Laboratory for Marine MeteorologyKey Laboratory of Climate Resources and Environment in Continental Shelf Sea and Deep Ocean(LCRE)。
文摘The multiscale variability in summer extreme persistent precipitation(SEPP)in China from 1961 to 2020 was investigated via three extreme precipitation indices:consecutive wet days,total precipitation amount,and daily precipitation intensity.The relationships between precursory and concurrent global oceanic modes and SEPP were identified via a generalized linear model(GLM).The influence of oceanic modes on SEPP was finally investigated via numerical simulations.The results revealed that the climatological SEPP(≥14 days)mainly appears across the Tibetan Plateau,Yunnan–Guizhou Plateau,and South China coast.The first EOF mode for all three indices showed strong signals over the Yangtze River.Further analysis via the GLM suggested that the positive phases of the tropical North Atlantic(TNA)in autumn,ENSO in winter,the Indian Ocean Basin(IOB)in spring,and the western North Pacific(WNP)in summer emerged as the most effective precursory factors of SEPP,which could serve as preceding signals for future predictions,contributing 30.2%,36.4%,38.0%,and 55.6%,respectively,to the GLM.Sensitivity experiments revealed that SST forcing in all four seasons contributes to SEPP over China,whereas the winter and summer SST warming over the Pacific and Indian Ocean(IO)contributes the most.Diagnosis of the hydrological cycle suggested that water vapor advection predominantly originates from the western Pacific and IO in summer,driven by the strengthened subtropical high and Asian summer monsoon(ASM).The enhanced vertical water vapor transport is attributed to stronger upward motion across all four seasons.These findings are helpful for better understanding SEPP variabilities and their prediction under SST warming.
文摘Dear Editor,Brown syndrome is an ocular motility disorder characterized by restriction of elevation in adduction combined with a positive forced duction test and minimal or no superior oblique(SO)overaction[1].Other features include V-pattern horizontal deviation and palpebral fissure widening while adduction[1].
基金funding from the NFR COMBINED (Grant No.328935)The BCPU hosted YZ visit to University of Bergen (Trond Mohn Foundation Grant No.BFS2018TMT01)+2 种基金supported by the National Key Research and Development Program of China (Grant No.2023YFA0805101)the National Natural Science Foundation of China (Grant Nos.42376250 and 41731177)a China Scholarship Council fellowship and the UTFORSK Partnership Program (CONNECTED UTF-2016-long-term/10030)。
文摘Spring consecutive rainfall events(CREs) are key triggers of geological hazards in the Three Gorges Reservoir area(TGR), China. However, previous projections of CREs based on the direct outputs of global climate models(GCMs) are subject to considerable uncertainties, largely caused by their coarse resolution. This study applies a triple-nested WRF(Weather Research and Forecasting) model dynamical downscaling, driven by a GCM, MIROC6(Model for Interdisciplinary Research on Climate, version 6), to improve the historical simulation and reduce the uncertainties in the future projection of CREs in the TGR. Results indicate that WRF has better performances in reproducing the observed rainfall in terms of the daily probability distribution, monthly evolution and duration of rainfall events, demonstrating the ability of WRF in simulating CREs. Thus, the triple-nested WRF is applied to project the future changes of CREs under the middle-of-the-road and fossil-fueled development scenarios. It is indicated that light and moderate rainfall and the duration of continuous rainfall spells will decrease in the TGR, leading to a decrease in the frequency of CREs. Meanwhile, the duration, rainfall amount, and intensity of CREs is projected to regional increase in the central-west TGR. These results are inconsistent with the raw projection of MIROC6. Observational diagnosis implies that CREs are mainly contributed by the vertical moisture advection. Such a synoptic contribution is captured well by WRF, which is not the case in MIROC6,indicating larger uncertainties in the CREs projected by MIROC6.
基金Financial support is provided by the National Natural Science Foundation of China(No.22225106)Fundamental Research Funds from Sichuan University(No.2020SCUNL102)the Fundamental Research Funds for the Central Universities。
文摘Dicarboxylic acids have a wide range of applications in the polymer industry to construct valuable materials.Photocatalysis has recently emerged as an efficient and sustainable strategy to generate dicarboxylic acids.However,photocatalytic dicarboxylation with CO_(2) is mainly limited to unsaturated bonds,and the dicarboxylation of C-C single bonds still remains a challenge.Herein,we report a photocatalytic dicarboxylation of C-C single bonds in strained rings with CO_(2) units via consecutive photo-induced electron transfer(ConPET).It is also the first photocatalytic reductive ring-opening reaction of cyclobutanes.Notably,this transition-metal-free protocol exhibits good functional group tolerance,broad substrate scope,facile scalability,and easy product derivatizations.Moreover,diacids can easily be derivatized to mainchain liquid crystalline polyesters.
文摘For some important object recognition applications such as intelligent robots and unmanned driving, images are collected on a consecutive basis and associated among themselves, besides, the scenes have steady prior features. Yet existing technologies do not take full advantage of this information. In order to take object recognition further than existing algorithms in the above application, an object recognition method that fuses temporal sequence with scene priori information is proposed. This method first employs YOLOv3 as the basic algorithm to recognize objects in single-frame images, then the DeepSort algorithm to establish association among potential objects recognized in images of different moments, and finally the confidence fusion method and temporal boundary processing method designed herein to fuse, at the decision level, temporal sequence information with scene priori information. Experiments using public datasets and self-built industrial scene datasets show that due to the expansion of information sources, the quality of single-frame images has less impact on the recognition results, whereby the object recognition is greatly improved. It is presented herein as a widely applicable framework for the fusion of information under multiple classes. All the object recognition algorithms that output object class, location information and recognition confidence at the same time can be integrated into this information fusion framework to improve performance.
文摘According to the daily precipitation data in artificial precipitation season during May to September from 1961 to 2008 in Liaoning Province,the maximum consecutive precipitation in the artificial precipitation test area is studied based on the maximum consecutive precipitation from May to September in 48 years.The results shows that the period of maximum consecutive precipitation in each month is different,and the variance trends of maximum consecutive precipitation in May,July,August and September are decreasing,while the variance trend of maximum consecutive precipitation in June is increasing.
基金the financial support of the State Basic Research Project ‘‘973’’ by the Ministry of Science and Technology of People’s Republic of China (2006CB202508)
文摘Hollow titanium silicalite （HTS） molecular sieve has been synthesized, and information on its structure, physico- chemical characterization, as well as surface property was investigated by a host of analytical methods, such as XRF, XRD, low-temperature N2 adsorption/desorption, TEM, FT-IR, UV-Vis, 29Si MAS NIVIR, and XPS techniques. The characterization results suggest that HTS zeolite has a special hollow crystal structure and its mesopore volume is larger than that of TS-1 zeolite. The titanium species in this zeolite are composed of the framework tetrahedral Ti （IV） ions and extra-framework octahedral Ti （IV） ions, which tend to disperse into its bulk phase. This zeolite material also has been applied to catalyze the cyclohexanone oxidation process, and the products are not completely consistent with those results obtained by using TS-1 zeolite, which might be caused by their difference in pore structure and pore volume, especially the mesopore volume. Cy- clohexanone oxidation catalyzed by HTS zeolite is a representative consecutive reaction, the main target products of which are e-caprolactone, 6-hydroxyhexanoic acid and adipic acid. The effect of H202/cyclohexanone mole ratio on the cyclohexa- none conversion, the total target product selectivity, the distribution of three target products selectivity and their variations along with reaction time is also researched and analyzed, which indicate that HTS zeolite shows a high performance for the Baeyer-Villiger reaction of cyclohexanone and catalytic oxidation of 6-hydroxyhexanoic acid under mild conditions, and the quantity of active surface titanium species as well as the pore structure and mesopore volume controlling the mass diffusion rate are the key factors determining the catalytic activity of HTS zeolite and product selectivity.
基金National Natural Science Foundation of China,No.41571044,No.41001283China Clean Development Mechanism(CDM)Fund Project,No.2012043CAS Pilot Special Project,No.XDA05090204
文摘Based on daily surface climate data and weather phenomenon data, the spatial and temporal distribution and trend on the number of consecutive days of severe weathers were analyzed in China during 1959-2014. The results indicate that the number of consecutive days for hot weathers increased at a rate of 0.1 day per decade in China as a whole, while that for cold weathers, snowfall weathers, thunderstorm weathers and foggy weathers showed significant decreasing trends at rates of 1.4, 0.3, 0.4 and 0.4 day per decade, re- spectively. Spatially, there were more consecutive hot days and rainstorm days in southeast- ern China, and more consecutive cold days and snowfall days in northeastern China and western China. Consecutive thunderstorm days were more in southern China and south- western China, and consecutive foggy days were more in some mountain stations. Over the past 56 years, annual number of consecutive cold days decreased mainly in most parts of western China and eastern China. Consecutive thunderstorm days decreased in most parts of China. The trend of consecutive hot days, snowfall days and foggy days was not significant in most parts of China, and that of consecutive rainstorm days was not significant in almost the entire China.
基金on a PhD scholarship sponsored by the University of Edinburgh
文摘Drought acutely affects economic sectors, natural habitats and communities. Understanding the past spatial and temporal patterns of drought is crucial because it facilitates the forecasting of future drought occurrences and informs decision-making processes for possible adaptive measures. This is especially important in view of a changing climate. This study employed the World Meteorological Organization(WMO)-recommended standardized precipitation index(SPI) to investigate the spatial and temporal patterns of drought in Zambia from 1960 to 2016. The relationship between the occurrence of consecutive dry days(CDD; consecutive days with less than 1 mm of precipitation) and SPI was also investigated. Horizontal wind vectors at 850 hPa during the core of the rainy season(December–February)were examined to ascertain the patterns of flow during years of extreme and severe drought; and these were contrasted with the patterns of flow in 2007, which was a generally wet year. Pressure vertical velocity was also investigated. Based on the gamma distribution, SPI successfully categorized extremely dry(with a SPI value less than or equal to –2.0) years over Zambia as 1992 and 2015, a severely dry(–1.9 to –1.5) year as 1995, moderately dry(–1.4 to –1.0) years as 1972, 1980, 1987, 1999 and 2005, and 26 near normal years(–0.9 to 0.9). The occurrence of CDD was found to be strongly negatively correlated with SPI with a coefficient of –0.6. Further results suggest that, during wet years, Zambia is influenced by a clockwise circulating low-pressure zone over the south-eastern Angola, a second such zone over the northern and eastern parts, and a third over the Indian Ocean. In stark contrast, years of drought were characterized by an anti-clockwise circulating high-pressure zone over the south-western parts of Zambia,constraining precipitation activities over the country. Further, wet years were characterized by negative pressure vertical velocity anomalies, signifying ascending motion; while drought years were dominated by positive anomalies, signifying descending motion, which suppresses precipitation. These patterns can be used to forecast drought over Zambia and aid in strategic planning to limit the potential damage of drought.
文摘The effects of higher modes and torsion have a significant impact on the seismic responses of asymmetric-plan tall buildings. A consecutive modal pushover (CMP) procedure is one of the pushover methods that have been developed to consider these effects. The aim of this paper is to modify the (CMP) analysis procedure to estimate the seismic demands of one-way asymmetric-plan tall buildings with dual systems. An analysis of 10-, 15- and 20-story asymmetric-plan buildings is carried out, and the results from the modified consecutive modal pushover (MCMP) procedure are compared with those obtained from the modal pushover analysis (MPA) procedure and the nonlinear time history analysis (NLTHA). The MCMP estimates of the seismic demands of one-way asymmetric-plan buildings demonstrate a reasonable accuracy, compared to the results obtained from the NLTHA. Furthermore, the accuracy of the MCMP procedure in the prediction of plastic hinge rotations is better than the MPA procedure. The new pushover procedure is also more accurate than the FEMA load distribution and the MPA procedure.
基金supported by the National Natural Science Foundation of China (71271170 71101116)+1 种基金the National High Technology Research and Development Program of China (863 Progrom) (2012AA040914)the Basic Research Foundation of Northwestern Polytechnical University (JC20120228)
文摘Importance measures in reliability systems are used to identify weak components in contributing to a proper function of the system. Traditional importance measures mainly concerned the changing value of the system reliability caused by the change of the reliability of the component, and seldom considered the joint effect of the probability distribution, improvement rate of the object component. This paper studies the rate of the system reliability upgrading with an improvement of the component reliability for the multi-state consecutive k-out-of-n system. To verify the multi-state consecutive k-out-of-n system reliability upgrading by improving one component based on its improvement rate, an increasing potential importance （IPI） and its physical meaning are described at first. Secondly, the relationship between the IPI and Birnbaum importance measures are discussed. And the IPI for some different improvement actions of the component is further discussed. Thirdly, the characteristics of the IPI are analyzed. Finally, an application to an oil pipeline system is given.
基金supported by the Hubei Provincial Natural Science Foundation of China(No.2018CFB378)
文摘Multistage hydraulic fracturing in horizontal wells is a critical technique for developing unconventional oil and gas resources.Stress interactions among neighboring fractures cause immature fracture development.The Texas two-step fracturing(TTSF)method is a new technique that aims to enhance fracture complexity and conductivity.This paper compares the fracture development of consecutive fracturing and the TTSF.The fracturing sequence in the multistage fracturing method has a significant effect on the fracture length,fracture width and injection pres sure.The consecutive fracturing results in relatively uneven fracture length and width.Certain fractures in consecutive fracturing are restrained to be closed due to the strong stress shadowing effect.In contrast,TTSF has considerable potential for alleviating the negative effects of stress interactions and producing a larger stimulated reservoir volume.
基金supported by the National Key Technologies R&D Program of China under Grant No. 2015BAK38B01the National Natural Science Foundation of China under Grant Nos. 61174103 and 61603032+4 种基金the National Key Research and Development Program of China under Grant Nos. 2016YFB0700502, 2016YFB1001404, and 2017YFB0702300the China Postdoctoral Science Foundation under Grant No. 2016M590048the Fundamental Research Funds for the Central Universities under Grant No. 06500025the University of Science and Technology Beijing - Taipei University of Technology Joint Research Program under Grant No. TW201610the Foundation from the Taipei University of Technology of Taiwan under Grant No. NTUT-USTB-105-4
文摘Quantized kernel least mean square(QKLMS) algorithm is an effective nonlinear adaptive online learning algorithm with good performance in constraining the growth of network size through the use of quantization for input space. It can serve as a powerful tool to perform complex computing for network service and application. With the purpose of compressing the input to further improve learning performance, this article proposes a novel QKLMS with entropy-guided learning, called EQ-KLMS. Under the consecutive square entropy learning framework, the basic idea of entropy-guided learning technique is to measure the uncertainty of the input vectors used for QKLMS, and delete those data with larger uncertainty, which are insignificant or easy to cause learning errors. Then, the dataset is compressed. Consequently, by using square entropy, the learning performance of proposed EQ-KLMS is improved with high precision and low computational cost. The proposed EQ-KLMS is validated using a weather-related dataset, and the results demonstrate the desirable performance of our scheme.
基金supported in part by the National Natural Science Foundation of China(61333003,61690212)
文摘This paper investigates the remote tracking control problem of Network-based Agents with communication delays existing in both forward and feedback communication channels.A networked predictive tracking controller is proposed to compensate the negative effects caused by bilateral time-delays in a wireless network.Furthermore,the problem of consecutive data loss in the feedback channel is solved using aforementioned controller,where lateral movement perturbations are introduced.Simulations and experiments are provided for several cases,which verify the realizability and effectiveness of the proposed controller.
