Non-farm income sources are important for livelihood sustenance,especially in the mountainous regions of developing countries.To implement effective policies to improve economic development,policymakers need insights ...Non-farm income sources are important for livelihood sustenance,especially in the mountainous regions of developing countries.To implement effective policies to improve economic development,policymakers need insights at the grassroots level.Yet,there is a lack of empirical evidence in the context of Pakistan.This study examines the current situation and the factors influencing the decision by farmers to engage in other gainful activities(OGAs)such as farm diversification and off-farm work in the northern mountainous regions of Pakistan.The study is based on quantitative survey data obtained from 459 farm managers and qualitative data from 24 key informants from five different districts in GilgitBaltistan.Utilizing a logistic regression model,a statistical analysis is conducted on farmer and farm characteristics to investigate the probability of farm managers to engage in OGAs.The survey results show that around 71%of farm managers are engaged in OGAs(with 24%in farm diversification,61%in offfarm work and 15%in both).The share of female farm managers is 51%in farm diversification while male farm managers dominate off-farm activities(69%).The most prevalent types of farm diversification are the processing of farm products and tourism-related farm work,while the main off-farm activities are setting up grocery stores outside the farm,having salaried jobs or engaging in other non-agricultural business.There are significant differences between farmers with and without OGAs particularly regarding farmer characteristics,agricultural income and some other variables.The logit model results show that farmer characteristics mainly determine off-farm work activities while farm(and other)characteristics mostly explain farm diversification.These findings suggest that OGAs primarily exist as livelihood strategies.Farm diversification is linked with the long-term sustenance of agricultural activities while off-farm work is predominantly driven by economic needs.Both types of OGAs require specific support policies while attention needs to be given not to threaten regional food supply.展开更多
The replacement of winter wheat varieties has contributed significantly to yield improvement worldwide,with remarkable progress in China.Drawing on two sets of data,production yield from the National Bureau of Statist...The replacement of winter wheat varieties has contributed significantly to yield improvement worldwide,with remarkable progress in China.Drawing on two sets of data,production yield from the National Bureau of Statistics of China and experimental yield from literature,this study aims to(1)illustrate the increasing patterns of production yield among different provinces from 1978 to 2018 in China,(2)explore the genetic gain in yield and yield relevant traits through the variety replacement based on experimental yield from 1937 to 2016 in China,and(3)compare the yield gap between experimental yield and production yield.The results show that both the production and experimental yields significantly increased along with the variety replacement.The national annual yield increase ratio for the production yield was 1.67%from 1978 to 2018,varying from 0.96%in Sichuan Province to 2.78%in Hebei Province;such ratio for the experimental yield was 1.13%from 1937 to 2016.The yield gap between experimental and production yields decreased from the 1970s to the 2010s.This study reveals significant increases in some yield components consequent to variety replacement,including thousand-grain weight,kernel number per spike,and grain number per square meter;however,no change is shown in spike number per square meter.The biomass and harvest index consistently and significantly increased,whereas the plant height decreased significantly.展开更多
Understanding understory seedling regeneration mechanisms is important for the sustainable development of temperate primary forests in the context of increasingly intense climate warming events.The poor regeneration o...Understanding understory seedling regeneration mechanisms is important for the sustainable development of temperate primary forests in the context of increasingly intense climate warming events.The poor regeneration of dominant tree species,however,is one of the biggest challenges it faces at the moment.Especially,the regeneration of the shade-intolerant Quercus mongolica seedling is difficult in primary forests,which contrasts with the extreme abundance of understory seedlings in secondary forests.The mechanism behind the interesting phenomenon is still unknown.This study used in-situ monitoring and nursery-controlled experiment to investigate the survival rate,growth performance,as well as nonstructural carbohydrate (NSC) concentrations and pools of various organ tissues of seedlings for two consecutive years,further analyze the understory light availability and simulate the foliage carbon (C) gain in the secondary and primary forest.Results suggested that seedlings in the secondary forest had greater biomass allocation aboveground,height and specific leaf area (SLA) in summer,which allowed the seedling to survive longer in the canopy closure period.High light availability and positive C gain in early spring and late autumn are key factors affecting the growth and survival of understory seedlings in the secondary forest,whereas seedlings in the primary forest had annual negative carbon gain.Through the growing season,the total NSC concentrations of seedlings gradually decreased,whereas those of seedlings in the secondary forest increased significantly in autumn,and were mainly stored in roots for winter consumption and the following year's summer shade period,which was verified by the nursery-controlled experiment that simulated autumn enhanced light availability improved seedling survival rate and NSC pools.In conclusion,our results revealed the survival trade-off strategies of Quercus mongolica seedlings and highlighted the necessity of high light availability during the spring and autumn phenological periods for shade-intolerant tree seedling recruitment.展开更多
Background The establishment of a robust gut microbiota in piglets during their early developmental stage holds the potential for long-term advantageous effects.However,the optimal timeframe for introducing probiotics...Background The establishment of a robust gut microbiota in piglets during their early developmental stage holds the potential for long-term advantageous effects.However,the optimal timeframe for introducing probiotics to achieve this outcome remains uncertain.Results In the context of this investigation,we conducted a longitudinal assessment of the fecal microbiota of 63 piglets at three distinct pre-weaning time points.Simultaneously,we gathered vaginal and fecal samples from 23 sows.Employing 16S rRNA gene and metagenomic sequencing methodologies,we conducted a comprehensive analysis of the fluctuation patterns in microbial composition,functional capacity,interaction networks,and colonization resistance within the gut microbiota of piglets.As the piglets progressed in age,discernible modifications in intestinal microbial diversity,composition,and function were observed.A source-tracking analysis unveiled the pivotal role of fecal and vaginal microbiota derived from sows in populating the gut microbiota of neonatal piglets.By D21,the microbial interaction network displayed a more concise and efficient configuration,accompanied by enhanced colonization resistance relative to the other two time points.Moreover,we identified three strains of Ruminococcus sp.at D10 as potential candidates for improving piglets’weight gain during the weaning phase.Conclusions The findings of this study propose that D10 represents the most opportune juncture for the introduction of external probiotic interventions during the early stages of piglet development.This investigation augments our comprehension of the microbiota dynamics in early-life of piglets and offers valuable insights for guiding forthcoming probiotic interventions.展开更多
Background Rumen bacterial groups can affect growth performance,such as average daily gain(ADG),feed intake,and efficiency.The study aimed to investigate the inter-relationship of rumen bacterial composition,rumen fer...Background Rumen bacterial groups can affect growth performance,such as average daily gain(ADG),feed intake,and efficiency.The study aimed to investigate the inter-relationship of rumen bacterial composition,rumen fermentation indicators,serum indicators,and growth performance of Holstein heifer calves with different ADG.Twelve calves were chosen from a trail with 60 calves and divided into higher ADG(HADG,high pre-and post-weaning ADG,n=6)and lower ADG(LADG,low pre-and post-weaning ADG,n=6)groups to investigate differences in bacterial composition and functions and host phenotype.Results During the preweaning period,the relative abundances of propionate producers,including g_norank_f_Butyricicoccaceae,g_Pyramidobacter,and g_norank_f_norank_o_Clostridia_vadin BB60_group,were higher in HADG calves(LDA>2,P<0.05).Enrichment of these bacteria resulted in increased levels of propionate,a gluconeogenic precursor,in preweaning HADG calves(adjusted P<0.05),which consequently raised serum glucose concentrations(adjusted P<0.05).In contrast,the relative abundances of rumen bacteria in post-weaning HADG calves did not exert this effect.Moreover,no significant differences were observed in rumen fermentation parameters and serum indices between the two groups.Conclusions The findings of this study revealed that the preweaning period is the window of opportunity for rumen bacteria to regulate the ADG of calves.展开更多
To determine the invasiveness of invasive plants,many studies have compared photosynthetic traits or strategies between invasive and native species.However,few studies have compared the photosynthetic dynamics between...To determine the invasiveness of invasive plants,many studies have compared photosynthetic traits or strategies between invasive and native species.However,few studies have compared the photosynthetic dynamics between invasive and native species during light fluctuations.We compared photosynthetic induction,relaxation dynamics and leaf traits between the invasive species,Tithonia diversifolia and two native species,Clerodendrum bungei and Blumea balsamifera,in full-sun and shady habitats.The photosynthetic dynamics and leaf traits differed among species.T.diversifolia showed a slower induction speed and stomatal opening response but had higher average intrinsic water-use efficiency than the two native species in full-sun habitats.Thus,the slow induction response may be attributed to the longer stomatal length in T.diversifolia.Habitat had a significant effect on photosynthetic dynamics in T.diversifolia and B.balsamifera but not in C.bungei.In shady habitat,T.diversifolia had a faster photosynthetic induction response than in full-sun habitat,leading to a higher average stomatal conductance during photosynthetic induction in T.diversifolia than in the two native species.In contrast,B.balsamifera had a larger stomatal length and slower photosynthetic induction and relaxation response in shady habitat than in full-sun habitat,resulting in higher carbon gain during photosynthetic relaxation.Nevertheless,in both habitats,T.diversifolia had an overall higher carbon gain during light fluctuations than the two native species.Our results indicated that T.diversifolia can adopt more effective response strategies under fluctuating light environments to maximize carbon gain,which may contribute to its successful invasion.展开更多
We explore the nonlinear gain coupled Schrödinger system through the utilization of the variables separation method and ansatz technique.By employing these approaches,we generate hierarchies of explicit dissipati...We explore the nonlinear gain coupled Schrödinger system through the utilization of the variables separation method and ansatz technique.By employing these approaches,we generate hierarchies of explicit dissipative vector vortices(DVVs)that possess diverse vorticity values.Numerous fundamental characteristics of the DVVs are examined,encompassing amplitude profiles,energy fluxes,parameter effects,as well as linear and dynamic stability.展开更多
Collisions between a moving mass and an anti-collision device increase structural responses and threaten structural safety.An active mass damper(AMD)with stroke limitations is often used to avoid collisions.However,a ...Collisions between a moving mass and an anti-collision device increase structural responses and threaten structural safety.An active mass damper(AMD)with stroke limitations is often used to avoid collisions.However,a strokelimited AMD control system with a fixed limited area shortens the available AMD stroke and leads to significant control power.To solve this problem,the design approach with variable gain and limited area(VGLA)is proposed in this study.First,the boundary of variable-limited areas is calculated based on the real-time status of the moving mass.The variable gain(VG)expression at the variable limited area is deduced by considering the saturation of AMD stroke.Then,numerical simulations of a stroke-limited AMD control system with VGLA are conducted on a high-rise building structure.These numerical simulations show that the proposed approach has superior strokelimitation performance compared with a stroke-limited AMD control system with a fixed limited area.Finally,the proposed approach is validated through experiments on a four-story steel frame.展开更多
We investigate the higher-order topological laser in the two-dimensional(2D) coupled-cavity array. By adding staggered on-site gain and loss to the 2D Hermitian array with a trivial phase, the system will emerge degen...We investigate the higher-order topological laser in the two-dimensional(2D) coupled-cavity array. By adding staggered on-site gain and loss to the 2D Hermitian array with a trivial phase, the system will emerge degenerate topological corner modes, which are protected by bulk band gap. For such a non-Hermitian model, by adjusting the parameters of the system and introducing the pumping into the cavity at the corner, a single-mode lasing with topological protection emerges.Furthermore, single-mode lasing exists over a wide range of pumping strengths. No matter where the cavity is initially stimulated, after enough time evolution, all the cavities belonging to the topological corner mode can emit a stable laser.展开更多
In order to enhance the accuracy of Air Traffic Control(ATC)cybersecurity attack detection,in this paper,a new clustering detection method is designed for air traffic control network security attacks.The feature set f...In order to enhance the accuracy of Air Traffic Control(ATC)cybersecurity attack detection,in this paper,a new clustering detection method is designed for air traffic control network security attacks.The feature set for ATC cybersecurity attacks is constructed by setting the feature states,adding recursive features,and determining the feature criticality.The expected information gain and entropy of the feature data are computed to determine the information gain of the feature data and reduce the interference of similar feature data.An autoencoder is introduced into the AI(artificial intelligence)algorithm to encode and decode the characteristics of ATC network security attack behavior to reduce the dimensionality of the ATC network security attack behavior data.Based on the above processing,an unsupervised learning algorithm for clustering detection of ATC network security attacks is designed.First,determine the distance between the clustering clusters of ATC network security attack behavior characteristics,calculate the clustering threshold,and construct the initial clustering center.Then,the new average value of all feature objects in each cluster is recalculated as the new cluster center.Second,it traverses all objects in a cluster of ATC network security attack behavior feature data.Finally,the cluster detection of ATC network security attack behavior is completed by the computation of objective functions.The experiment took three groups of experimental attack behavior data sets as the test object,and took the detection rate,false detection rate and recall rate as the test indicators,and selected three similar methods for comparative test.The experimental results show that the detection rate of this method is about 98%,the false positive rate is below 1%,and the recall rate is above 97%.Research shows that this method can improve the detection performance of security attacks in air traffic control network.展开更多
Objective:Postpartum weight retention(PPWR)is a common problem among women after childbirth.The main objectives of this study are to understand the changes in body weight of breastfeeding mothers during long-term foll...Objective:Postpartum weight retention(PPWR)is a common problem among women after childbirth.The main objectives of this study are to understand the changes in body weight of breastfeeding mothers during long-term follow-up and preliminarily explore the relationship between maternal body weight and human milk composition,including macronutrients,leptin,and adiponectin.Methods:The study included a longitudinal cohort(122 mothers),and a cross-sectional cohort(37 mothers).The human milk,maternal weight,and dietary surveys were collected in the longitudinal cohort at different follow-up time points(1-14 days postpartum,2-4 months postpartum,5-7 months postpartum,and 12-17 months postpartum).The maternal body weight was analyzed using the responses in the survey questionnaires.A milk analyzer based on the mid-infrared spectroscopy(MIRS)was used to determine milk composition,and nutrition analysis software evaluated dietary intakes.In the cross-sectional cohort,participating mothers were asked to provide blood and human milk samples and pertinent information related to maternal body composition.Maternal body composition was measured by bioelectrical impedance analysis(BIA),while ELISA analyzed leptin and adiponectin in milk and serum.Results:At 5-7 months postpartum,the PPWR of breastfeeding mothers was(2.46±3.59)kg.At 12-17 months postpartum,the PPWR was(0.98±4.06)kg.PPWR was found to be negatively correlated with milk fat content within 14 days postpartum and positively correlated at 2-4 months postpartum.In addition,the maternal weight and body muscle mass were positively correlated with leptin and adiponectin in milk.Plasma leptin was positively correlated with the mother’s body weight,body mass index(BMI),FAT percentage,and body fat mass,while plasma adiponectin did not correlate with any parameter.The results also indicate that the PPWR did not correlate with leptin and adiponectin in plasma or milk.Conclusions:Breastfeeding mothers may retain considerable weight gain one year after delivery.Human milk composition may be related to changes in maternal body weight.Leptin and adiponectin in breast milk and leptin in plasma are associated with the maternal body composition.This study supports the notion that maternal nutritional status may affect offspring health through lactation,and future research should focus on exploring weight management of postpartum mothers.展开更多
In recent years,switched inductor(SL)technology,switched capacitor(SC)technology,and switched inductor-capacitor(SL-SC)technology have been widely applied to optimize and improve DC-DC boost converters,which can effec...In recent years,switched inductor(SL)technology,switched capacitor(SC)technology,and switched inductor-capacitor(SL-SC)technology have been widely applied to optimize and improve DC-DC boost converters,which can effectively enhance voltage gain and reduce device stress.To address the issue of low output voltage in current renewable energy power generation systems,this study proposes a novel non-isolated cubic high-gain DC-DC converter based on the traditional quadratic DC-DC boost converter by incorporating a SC and a SL-SC unit.Firstly,the proposed converter’s details are elaborated,including its topology structure,operating mode,voltage gain,device stress,and power loss.Subsequently,a comparative analysis is conducted on the voltage gain and device stress between the proposed converter and other high-gain converters.Then,a closed-loop simulation system is constructed to obtain simulation waveforms of various devices and explore the dynamic performance.Finally,an experimental prototype is built,experimental waveforms are obtained,and the experimental dynamic performance and conversion efficiency are analyzed.The theoretical analysis’s correctness is verified through simulation and experimental results.The proposed converter has advantages such as high voltage gain,low device stress,high conversion efficiency,simple control,and wide input voltage range,achieving a good balance between voltage gain,device stress,and power loss.The proposed converter is well-suited for renewable energy systems and holds theoretical significance and practical value in renewable energy applications.It provides an effective solution to the issue of low output voltage in renewable energy power generation systems.展开更多
On December 12,2023,Kenya celebrated its 60th anniversary of independence.Since independence,Kenya’s political operations have long been characterized by tribal politics,and during the 2022 elections,United Democrati...On December 12,2023,Kenya celebrated its 60th anniversary of independence.Since independence,Kenya’s political operations have long been characterized by tribal politics,and during the 2022 elections,United Democratic Alliance(UDA)presidential candidate William Samoei Ruto advocated a Hustler Movement with a platform focused on serving the interests of the underprivileged.The Movement,with its policy orientation of responding to the concerns of the hustler(refer to those forced to squeeze out a meagre living on the margins of society comparing to people from Kenya’s big-name families),seeks to move electoral politics away from the previous competition at the tribal and regional levels,and to construct an issue-oriented mode of political operation,which has given a new meaning to the development of Kenyan politics.Ruto became president in September 2022 after the Hustler Movement gained broad social support.Over the past years,the Ruto government has transformed the Hustler Movement’s policy ideas into a program of governance,reshaping Kenya’s political development agenda in practical terms.The influence of the Hustler Movement has become more and more visible,deeply reflecting the trend of Kenya’s political development over the past 60 years of independence.展开更多
China gained full access to the internet on April 20,1994.The past 30 years have witnessed continuous efforts in China to boost its connections with the global community while vigorously advancing reform and opening-u...China gained full access to the internet on April 20,1994.The past 30 years have witnessed continuous efforts in China to boost its connections with the global community while vigorously advancing reform and opening-up.The internet has shaped and changed our lives.Through an internet connection,strangers thousands of miles away become friends and maintain close interactions,everyone including those living in rural and remote areas are able to enjoy equal access to medical and educational resources,and exchange of goods between individuals has become convenient like never before,sparking the emergence of new forms of business.Middle-aged people tend to reminisce about the past when everything moved slower,whereas younger generations fifind it hard to imagine how people survived without networks.展开更多
China’s Jingmai Mountain Ancient Tea Forest has gained fame and revitalized villagers’fortunes.“Big tea trees in Aileng Moutain are in bud.We cut the branches down,grow them in our village.They withstand winds,rain...China’s Jingmai Mountain Ancient Tea Forest has gained fame and revitalized villagers’fortunes.“Big tea trees in Aileng Moutain are in bud.We cut the branches down,grow them in our village.They withstand winds,rains,and time.Precious as gold,they bring us fortune and happiness.”Yu Luo,an elderly woman dressed in a traditional costume of the Blang ethnic group,sat in an old village and sang this beautiful folk song,praising the ancient tea forest that has supported her village for generations.“For over a millennia,people here have been living with the tea forest.The small tea leaves are treasures that nature has given us,”she said.展开更多
In 2023,China’s natural gas sector experienced robust growth in both supply and demand dynamics,as consumption regained an upward trend,reaching 394.53 billion m3,reflecting a 7.6%year-on-year surge.Domestic gas prod...In 2023,China’s natural gas sector experienced robust growth in both supply and demand dynamics,as consumption regained an upward trend,reaching 394.53 billion m3,reflecting a 7.6%year-on-year surge.Domestic gas production and reserves persistently progressed,hitting a production volume of 228.84 billion m3 and achieving a seven-year consecutive increment exceeding 10 billion m^(3).After an initial sharp decline,imported natural gas rebounded to record growth;the combined import volume of pipeline gas and LNG climbed to 163.92 billion m^(3),a notable 11.3%rise compared to the previous year.As China’s policies for stable economic growth are further entrenched in 2024,the macroeconomic recovery is anticipated to continue.Bolstered by the dual-carbon strategy and the transformative policies targeting high-energy-consuming industries,the natural gas market is expected to sustain its rapid expansion,with estimated growth in demand ranging between 5.8%and 7.1%.展开更多
Fostering intelligent manufacturing bases is part of Shanghai’s effort to promote a green transition.IN recent years,Shanghai has begun implementing intelligent manufacturing projects.It has formulated plans for high...Fostering intelligent manufacturing bases is part of Shanghai’s effort to promote a green transition.IN recent years,Shanghai has begun implementing intelligent manufacturing projects.It has formulated plans for high-quality development,built high-standard smart factories,cultivated capable companies,and set up efficient public service platforms.As a result,it has gained an overall advantage with its high-end value chain,a complete industrial chain,a coordinated innovation chain,and a concentrated resource chain,which have made“Shanghai manufacturing”intelligent.展开更多
The ongoing decline of the predatory development model and the zero-sum mentality advocated by the Western powers gives every reason to believe that the world is in a period of unprecedented upheaval.The“two sessions...The ongoing decline of the predatory development model and the zero-sum mentality advocated by the Western powers gives every reason to believe that the world is in a period of unprecedented upheaval.The“two sessions”(China’s biggest annual political event)this March gained unprecedented attention worldwide,particularly from Belt and Road countries which have been actively aligning their development strategies with those of China.China’s GDP growth,economic policies,and development trends in 2024 were the focus of discussion.展开更多
This work details the development of a broad-spectrum LNA (Low Noise Amplifier) circuit using a 65 nm CMOS technology. The design incorporates an inductive degeneracy circuit, employing a theoretical approach to enhan...This work details the development of a broad-spectrum LNA (Low Noise Amplifier) circuit using a 65 nm CMOS technology. The design incorporates an inductive degeneracy circuit, employing a theoretical approach to enhance gain, minimize noise levels, and uphold low power consumption. The progression includes a shift to a cascode structure to further refine LNA parameters. Ultimately, with a 1.8 V bias, the achieved performance showcases a gain-to-noise figure ratio of 16 dB/0.5 dB, an IIP3 linearity at 5.1 dBm, and a power consumption of 3 mW. This architecture is adept at operating across a wide frequency band spanning from 0.5 GHz to 6 GHz, rendering it applicable in diverse RF scenarios.展开更多
主题语境:人与社会篇幅:347词关键词:dance1 People spring into a freestyle street dance to the beat of a lively Chinese song,swinging their knees and ankles sideways while performing dazzling hand moves.This socalled“Ke...主题语境:人与社会篇幅:347词关键词:dance1 People spring into a freestyle street dance to the beat of a lively Chinese song,swinging their knees and ankles sideways while performing dazzling hand moves.This socalled“Kemusan”dance,translated as“Subject Three”dance,has gone viral in China and beyond,with people from all walks of life,including both Chinese and foreigners,joining in the fun.The dance has brought a lot of joy to young Chinese viewers and has gained popularity among people worldwide.展开更多
基金funded by the scholarship offered by the Free University of BozenBolzano。
文摘Non-farm income sources are important for livelihood sustenance,especially in the mountainous regions of developing countries.To implement effective policies to improve economic development,policymakers need insights at the grassroots level.Yet,there is a lack of empirical evidence in the context of Pakistan.This study examines the current situation and the factors influencing the decision by farmers to engage in other gainful activities(OGAs)such as farm diversification and off-farm work in the northern mountainous regions of Pakistan.The study is based on quantitative survey data obtained from 459 farm managers and qualitative data from 24 key informants from five different districts in GilgitBaltistan.Utilizing a logistic regression model,a statistical analysis is conducted on farmer and farm characteristics to investigate the probability of farm managers to engage in OGAs.The survey results show that around 71%of farm managers are engaged in OGAs(with 24%in farm diversification,61%in offfarm work and 15%in both).The share of female farm managers is 51%in farm diversification while male farm managers dominate off-farm activities(69%).The most prevalent types of farm diversification are the processing of farm products and tourism-related farm work,while the main off-farm activities are setting up grocery stores outside the farm,having salaried jobs or engaging in other non-agricultural business.There are significant differences between farmers with and without OGAs particularly regarding farmer characteristics,agricultural income and some other variables.The logit model results show that farmer characteristics mainly determine off-farm work activities while farm(and other)characteristics mostly explain farm diversification.These findings suggest that OGAs primarily exist as livelihood strategies.Farm diversification is linked with the long-term sustenance of agricultural activities while off-farm work is predominantly driven by economic needs.Both types of OGAs require specific support policies while attention needs to be given not to threaten regional food supply.
基金This research was financially supported by the Natural Science Basic Research Program of Shaanxi,China(2022JM-126)the National Natural Science Foundation of China(52079132).
文摘The replacement of winter wheat varieties has contributed significantly to yield improvement worldwide,with remarkable progress in China.Drawing on two sets of data,production yield from the National Bureau of Statistics of China and experimental yield from literature,this study aims to(1)illustrate the increasing patterns of production yield among different provinces from 1978 to 2018 in China,(2)explore the genetic gain in yield and yield relevant traits through the variety replacement based on experimental yield from 1937 to 2016 in China,and(3)compare the yield gap between experimental yield and production yield.The results show that both the production and experimental yields significantly increased along with the variety replacement.The national annual yield increase ratio for the production yield was 1.67%from 1978 to 2018,varying from 0.96%in Sichuan Province to 2.78%in Hebei Province;such ratio for the experimental yield was 1.13%from 1937 to 2016.The yield gap between experimental and production yields decreased from the 1970s to the 2010s.This study reveals significant increases in some yield components consequent to variety replacement,including thousand-grain weight,kernel number per spike,and grain number per square meter;however,no change is shown in spike number per square meter.The biomass and harvest index consistently and significantly increased,whereas the plant height decreased significantly.
基金supported by the Ministry of Science and Technology of China (No.2019FY101602)。
文摘Understanding understory seedling regeneration mechanisms is important for the sustainable development of temperate primary forests in the context of increasingly intense climate warming events.The poor regeneration of dominant tree species,however,is one of the biggest challenges it faces at the moment.Especially,the regeneration of the shade-intolerant Quercus mongolica seedling is difficult in primary forests,which contrasts with the extreme abundance of understory seedlings in secondary forests.The mechanism behind the interesting phenomenon is still unknown.This study used in-situ monitoring and nursery-controlled experiment to investigate the survival rate,growth performance,as well as nonstructural carbohydrate (NSC) concentrations and pools of various organ tissues of seedlings for two consecutive years,further analyze the understory light availability and simulate the foliage carbon (C) gain in the secondary and primary forest.Results suggested that seedlings in the secondary forest had greater biomass allocation aboveground,height and specific leaf area (SLA) in summer,which allowed the seedling to survive longer in the canopy closure period.High light availability and positive C gain in early spring and late autumn are key factors affecting the growth and survival of understory seedlings in the secondary forest,whereas seedlings in the primary forest had annual negative carbon gain.Through the growing season,the total NSC concentrations of seedlings gradually decreased,whereas those of seedlings in the secondary forest increased significantly in autumn,and were mainly stored in roots for winter consumption and the following year's summer shade period,which was verified by the nursery-controlled experiment that simulated autumn enhanced light availability improved seedling survival rate and NSC pools.In conclusion,our results revealed the survival trade-off strategies of Quercus mongolica seedlings and highlighted the necessity of high light availability during the spring and autumn phenological periods for shade-intolerant tree seedling recruitment.
基金supported by a Key Technologies R&D Program of Guangdong Province project(2022B0202090002)a China Postdoctoral Science Foundation(Grant No.2021M701263)+1 种基金a Local Innovative and Research Teams Project of Guangdong Province(2019BT02N630)a Project of Swine Innovation Team in the Guangdong Modern Agricultural Research System(2023KJ126).
文摘Background The establishment of a robust gut microbiota in piglets during their early developmental stage holds the potential for long-term advantageous effects.However,the optimal timeframe for introducing probiotics to achieve this outcome remains uncertain.Results In the context of this investigation,we conducted a longitudinal assessment of the fecal microbiota of 63 piglets at three distinct pre-weaning time points.Simultaneously,we gathered vaginal and fecal samples from 23 sows.Employing 16S rRNA gene and metagenomic sequencing methodologies,we conducted a comprehensive analysis of the fluctuation patterns in microbial composition,functional capacity,interaction networks,and colonization resistance within the gut microbiota of piglets.As the piglets progressed in age,discernible modifications in intestinal microbial diversity,composition,and function were observed.A source-tracking analysis unveiled the pivotal role of fecal and vaginal microbiota derived from sows in populating the gut microbiota of neonatal piglets.By D21,the microbial interaction network displayed a more concise and efficient configuration,accompanied by enhanced colonization resistance relative to the other two time points.Moreover,we identified three strains of Ruminococcus sp.at D10 as potential candidates for improving piglets’weight gain during the weaning phase.Conclusions The findings of this study propose that D10 represents the most opportune juncture for the introduction of external probiotic interventions during the early stages of piglet development.This investigation augments our comprehension of the microbiota dynamics in early-life of piglets and offers valuable insights for guiding forthcoming probiotic interventions.
基金funded by National Key R&D Program of China(2022YFA1304204)Agricultural Science and Technology Innovation Program(CAAS-ASTIP-2017-FRI-04)Beijing Innovation Consortium of livestock Research System(BAIC05-2023)。
文摘Background Rumen bacterial groups can affect growth performance,such as average daily gain(ADG),feed intake,and efficiency.The study aimed to investigate the inter-relationship of rumen bacterial composition,rumen fermentation indicators,serum indicators,and growth performance of Holstein heifer calves with different ADG.Twelve calves were chosen from a trail with 60 calves and divided into higher ADG(HADG,high pre-and post-weaning ADG,n=6)and lower ADG(LADG,low pre-and post-weaning ADG,n=6)groups to investigate differences in bacterial composition and functions and host phenotype.Results During the preweaning period,the relative abundances of propionate producers,including g_norank_f_Butyricicoccaceae,g_Pyramidobacter,and g_norank_f_norank_o_Clostridia_vadin BB60_group,were higher in HADG calves(LDA>2,P<0.05).Enrichment of these bacteria resulted in increased levels of propionate,a gluconeogenic precursor,in preweaning HADG calves(adjusted P<0.05),which consequently raised serum glucose concentrations(adjusted P<0.05).In contrast,the relative abundances of rumen bacteria in post-weaning HADG calves did not exert this effect.Moreover,no significant differences were observed in rumen fermentation parameters and serum indices between the two groups.Conclusions The findings of this study revealed that the preweaning period is the window of opportunity for rumen bacteria to regulate the ADG of calves.
基金financially supported by the National Natural Science Foundation of China(Grant number:32071661)。
文摘To determine the invasiveness of invasive plants,many studies have compared photosynthetic traits or strategies between invasive and native species.However,few studies have compared the photosynthetic dynamics between invasive and native species during light fluctuations.We compared photosynthetic induction,relaxation dynamics and leaf traits between the invasive species,Tithonia diversifolia and two native species,Clerodendrum bungei and Blumea balsamifera,in full-sun and shady habitats.The photosynthetic dynamics and leaf traits differed among species.T.diversifolia showed a slower induction speed and stomatal opening response but had higher average intrinsic water-use efficiency than the two native species in full-sun habitats.Thus,the slow induction response may be attributed to the longer stomatal length in T.diversifolia.Habitat had a significant effect on photosynthetic dynamics in T.diversifolia and B.balsamifera but not in C.bungei.In shady habitat,T.diversifolia had a faster photosynthetic induction response than in full-sun habitat,leading to a higher average stomatal conductance during photosynthetic induction in T.diversifolia than in the two native species.In contrast,B.balsamifera had a larger stomatal length and slower photosynthetic induction and relaxation response in shady habitat than in full-sun habitat,resulting in higher carbon gain during photosynthetic relaxation.Nevertheless,in both habitats,T.diversifolia had an overall higher carbon gain during light fluctuations than the two native species.Our results indicated that T.diversifolia can adopt more effective response strategies under fluctuating light environments to maximize carbon gain,which may contribute to its successful invasion.
基金supported by the National Natural Science Foundation of China(Grant Nos.11705164 and 11874324).
文摘We explore the nonlinear gain coupled Schrödinger system through the utilization of the variables separation method and ansatz technique.By employing these approaches,we generate hierarchies of explicit dissipative vector vortices(DVVs)that possess diverse vorticity values.Numerous fundamental characteristics of the DVVs are examined,encompassing amplitude profiles,energy fluxes,parameter effects,as well as linear and dynamic stability.
基金This research was founded by the Funds for Creative Research Groups of National Natural Science Foundation of China(Grant No.51921006)the National Natural Science Foundations of China(Grant No.51978224)+2 种基金the National Major Scientific Research Instrument Development Program of China(Grant No.51827811)the National Natural Science Foundation of China,(Grant No.52008141)the Shenzhen Technology Innovation Program(Grant Nos.JCYJ20170811160003571,JCYJ20180508152238111 and JCYJ20200109112803851).
文摘Collisions between a moving mass and an anti-collision device increase structural responses and threaten structural safety.An active mass damper(AMD)with stroke limitations is often used to avoid collisions.However,a strokelimited AMD control system with a fixed limited area shortens the available AMD stroke and leads to significant control power.To solve this problem,the design approach with variable gain and limited area(VGLA)is proposed in this study.First,the boundary of variable-limited areas is calculated based on the real-time status of the moving mass.The variable gain(VG)expression at the variable limited area is deduced by considering the saturation of AMD stroke.Then,numerical simulations of a stroke-limited AMD control system with VGLA are conducted on a high-rise building structure.These numerical simulations show that the proposed approach has superior strokelimitation performance compared with a stroke-limited AMD control system with a fixed limited area.Finally,the proposed approach is validated through experiments on a four-story steel frame.
基金supported by the National Natural Science Foundation of China (Grant Nos. 12274326 and 12174288)the National Key R&D Program of China (Grant No. 2021YFA1400602)。
文摘We investigate the higher-order topological laser in the two-dimensional(2D) coupled-cavity array. By adding staggered on-site gain and loss to the 2D Hermitian array with a trivial phase, the system will emerge degenerate topological corner modes, which are protected by bulk band gap. For such a non-Hermitian model, by adjusting the parameters of the system and introducing the pumping into the cavity at the corner, a single-mode lasing with topological protection emerges.Furthermore, single-mode lasing exists over a wide range of pumping strengths. No matter where the cavity is initially stimulated, after enough time evolution, all the cavities belonging to the topological corner mode can emit a stable laser.
基金National Natural Science Foundation of China(U2133208,U20A20161)National Natural Science Foundation of China(No.62273244)Sichuan Science and Technology Program(No.2022YFG0180).
文摘In order to enhance the accuracy of Air Traffic Control(ATC)cybersecurity attack detection,in this paper,a new clustering detection method is designed for air traffic control network security attacks.The feature set for ATC cybersecurity attacks is constructed by setting the feature states,adding recursive features,and determining the feature criticality.The expected information gain and entropy of the feature data are computed to determine the information gain of the feature data and reduce the interference of similar feature data.An autoencoder is introduced into the AI(artificial intelligence)algorithm to encode and decode the characteristics of ATC network security attack behavior to reduce the dimensionality of the ATC network security attack behavior data.Based on the above processing,an unsupervised learning algorithm for clustering detection of ATC network security attacks is designed.First,determine the distance between the clustering clusters of ATC network security attack behavior characteristics,calculate the clustering threshold,and construct the initial clustering center.Then,the new average value of all feature objects in each cluster is recalculated as the new cluster center.Second,it traverses all objects in a cluster of ATC network security attack behavior feature data.Finally,the cluster detection of ATC network security attack behavior is completed by the computation of objective functions.The experiment took three groups of experimental attack behavior data sets as the test object,and took the detection rate,false detection rate and recall rate as the test indicators,and selected three similar methods for comparative test.The experimental results show that the detection rate of this method is about 98%,the false positive rate is below 1%,and the recall rate is above 97%.Research shows that this method can improve the detection performance of security attacks in air traffic control network.
基金supported by grants from the Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition(17dz2272000)Foundation of Shanghai Municipal Health Commission(Key weak discipline construction project 2019ZB0101)the Scientific research fund of China Nutrition Society(CNSHPNK2021-16)。
文摘Objective:Postpartum weight retention(PPWR)is a common problem among women after childbirth.The main objectives of this study are to understand the changes in body weight of breastfeeding mothers during long-term follow-up and preliminarily explore the relationship between maternal body weight and human milk composition,including macronutrients,leptin,and adiponectin.Methods:The study included a longitudinal cohort(122 mothers),and a cross-sectional cohort(37 mothers).The human milk,maternal weight,and dietary surveys were collected in the longitudinal cohort at different follow-up time points(1-14 days postpartum,2-4 months postpartum,5-7 months postpartum,and 12-17 months postpartum).The maternal body weight was analyzed using the responses in the survey questionnaires.A milk analyzer based on the mid-infrared spectroscopy(MIRS)was used to determine milk composition,and nutrition analysis software evaluated dietary intakes.In the cross-sectional cohort,participating mothers were asked to provide blood and human milk samples and pertinent information related to maternal body composition.Maternal body composition was measured by bioelectrical impedance analysis(BIA),while ELISA analyzed leptin and adiponectin in milk and serum.Results:At 5-7 months postpartum,the PPWR of breastfeeding mothers was(2.46±3.59)kg.At 12-17 months postpartum,the PPWR was(0.98±4.06)kg.PPWR was found to be negatively correlated with milk fat content within 14 days postpartum and positively correlated at 2-4 months postpartum.In addition,the maternal weight and body muscle mass were positively correlated with leptin and adiponectin in milk.Plasma leptin was positively correlated with the mother’s body weight,body mass index(BMI),FAT percentage,and body fat mass,while plasma adiponectin did not correlate with any parameter.The results also indicate that the PPWR did not correlate with leptin and adiponectin in plasma or milk.Conclusions:Breastfeeding mothers may retain considerable weight gain one year after delivery.Human milk composition may be related to changes in maternal body weight.Leptin and adiponectin in breast milk and leptin in plasma are associated with the maternal body composition.This study supports the notion that maternal nutritional status may affect offspring health through lactation,and future research should focus on exploring weight management of postpartum mothers.
基金This work was supported by China Railway Corporation Science and Technology Research and Development Project(P2021J038).
文摘In recent years,switched inductor(SL)technology,switched capacitor(SC)technology,and switched inductor-capacitor(SL-SC)technology have been widely applied to optimize and improve DC-DC boost converters,which can effectively enhance voltage gain and reduce device stress.To address the issue of low output voltage in current renewable energy power generation systems,this study proposes a novel non-isolated cubic high-gain DC-DC converter based on the traditional quadratic DC-DC boost converter by incorporating a SC and a SL-SC unit.Firstly,the proposed converter’s details are elaborated,including its topology structure,operating mode,voltage gain,device stress,and power loss.Subsequently,a comparative analysis is conducted on the voltage gain and device stress between the proposed converter and other high-gain converters.Then,a closed-loop simulation system is constructed to obtain simulation waveforms of various devices and explore the dynamic performance.Finally,an experimental prototype is built,experimental waveforms are obtained,and the experimental dynamic performance and conversion efficiency are analyzed.The theoretical analysis’s correctness is verified through simulation and experimental results.The proposed converter has advantages such as high voltage gain,low device stress,high conversion efficiency,simple control,and wide input voltage range,achieving a good balance between voltage gain,device stress,and power loss.The proposed converter is well-suited for renewable energy systems and holds theoretical significance and practical value in renewable energy applications.It provides an effective solution to the issue of low output voltage in renewable energy power generation systems.
文摘On December 12,2023,Kenya celebrated its 60th anniversary of independence.Since independence,Kenya’s political operations have long been characterized by tribal politics,and during the 2022 elections,United Democratic Alliance(UDA)presidential candidate William Samoei Ruto advocated a Hustler Movement with a platform focused on serving the interests of the underprivileged.The Movement,with its policy orientation of responding to the concerns of the hustler(refer to those forced to squeeze out a meagre living on the margins of society comparing to people from Kenya’s big-name families),seeks to move electoral politics away from the previous competition at the tribal and regional levels,and to construct an issue-oriented mode of political operation,which has given a new meaning to the development of Kenyan politics.Ruto became president in September 2022 after the Hustler Movement gained broad social support.Over the past years,the Ruto government has transformed the Hustler Movement’s policy ideas into a program of governance,reshaping Kenya’s political development agenda in practical terms.The influence of the Hustler Movement has become more and more visible,deeply reflecting the trend of Kenya’s political development over the past 60 years of independence.
文摘China gained full access to the internet on April 20,1994.The past 30 years have witnessed continuous efforts in China to boost its connections with the global community while vigorously advancing reform and opening-up.The internet has shaped and changed our lives.Through an internet connection,strangers thousands of miles away become friends and maintain close interactions,everyone including those living in rural and remote areas are able to enjoy equal access to medical and educational resources,and exchange of goods between individuals has become convenient like never before,sparking the emergence of new forms of business.Middle-aged people tend to reminisce about the past when everything moved slower,whereas younger generations fifind it hard to imagine how people survived without networks.
文摘China’s Jingmai Mountain Ancient Tea Forest has gained fame and revitalized villagers’fortunes.“Big tea trees in Aileng Moutain are in bud.We cut the branches down,grow them in our village.They withstand winds,rains,and time.Precious as gold,they bring us fortune and happiness.”Yu Luo,an elderly woman dressed in a traditional costume of the Blang ethnic group,sat in an old village and sang this beautiful folk song,praising the ancient tea forest that has supported her village for generations.“For over a millennia,people here have been living with the tea forest.The small tea leaves are treasures that nature has given us,”she said.
文摘In 2023,China’s natural gas sector experienced robust growth in both supply and demand dynamics,as consumption regained an upward trend,reaching 394.53 billion m3,reflecting a 7.6%year-on-year surge.Domestic gas production and reserves persistently progressed,hitting a production volume of 228.84 billion m3 and achieving a seven-year consecutive increment exceeding 10 billion m^(3).After an initial sharp decline,imported natural gas rebounded to record growth;the combined import volume of pipeline gas and LNG climbed to 163.92 billion m^(3),a notable 11.3%rise compared to the previous year.As China’s policies for stable economic growth are further entrenched in 2024,the macroeconomic recovery is anticipated to continue.Bolstered by the dual-carbon strategy and the transformative policies targeting high-energy-consuming industries,the natural gas market is expected to sustain its rapid expansion,with estimated growth in demand ranging between 5.8%and 7.1%.
文摘Fostering intelligent manufacturing bases is part of Shanghai’s effort to promote a green transition.IN recent years,Shanghai has begun implementing intelligent manufacturing projects.It has formulated plans for high-quality development,built high-standard smart factories,cultivated capable companies,and set up efficient public service platforms.As a result,it has gained an overall advantage with its high-end value chain,a complete industrial chain,a coordinated innovation chain,and a concentrated resource chain,which have made“Shanghai manufacturing”intelligent.
文摘The ongoing decline of the predatory development model and the zero-sum mentality advocated by the Western powers gives every reason to believe that the world is in a period of unprecedented upheaval.The“two sessions”(China’s biggest annual political event)this March gained unprecedented attention worldwide,particularly from Belt and Road countries which have been actively aligning their development strategies with those of China.China’s GDP growth,economic policies,and development trends in 2024 were the focus of discussion.
文摘This work details the development of a broad-spectrum LNA (Low Noise Amplifier) circuit using a 65 nm CMOS technology. The design incorporates an inductive degeneracy circuit, employing a theoretical approach to enhance gain, minimize noise levels, and uphold low power consumption. The progression includes a shift to a cascode structure to further refine LNA parameters. Ultimately, with a 1.8 V bias, the achieved performance showcases a gain-to-noise figure ratio of 16 dB/0.5 dB, an IIP3 linearity at 5.1 dBm, and a power consumption of 3 mW. This architecture is adept at operating across a wide frequency band spanning from 0.5 GHz to 6 GHz, rendering it applicable in diverse RF scenarios.
文摘主题语境:人与社会篇幅:347词关键词:dance1 People spring into a freestyle street dance to the beat of a lively Chinese song,swinging their knees and ankles sideways while performing dazzling hand moves.This socalled“Kemusan”dance,translated as“Subject Three”dance,has gone viral in China and beyond,with people from all walks of life,including both Chinese and foreigners,joining in the fun.The dance has brought a lot of joy to young Chinese viewers and has gained popularity among people worldwide.