Heterogeneous population distribution enhances resistance to wheat lodging by optimizing the light environment

Lodging is still the key factor that limits continuous increases in wheat yields today,because the mechanical strength of culms is reduced due to low-light stress in populations under high-yield cultivation.The mechanical properties of the culm are mainly determined by lignin,which is affected by the light environment.However,little is known about whether the light environment can be sufficiently improved by changing the population distribution to inhibit culm lodging.Therefore,in this study,we used the wheat cultivar“Xinong 979”to establish a low-density homogeneous distribution treatment(LD),high-density homogeneous distribution treatment(HD),and high-density heterogeneous distribution treatment(HD-h)to study the regulatory effects and mechanism responsible for differences in the lodging resistance of wheat culms under different population distributions.Compared with LD,HD significantly reduced the light transmittance in the middle and basal layers of the canopy,the net photosynthetic rate in the middle and lower leaves of plants,the accumulation of lignin in the culm,and the breaking resistance of the culm,and thus the lodging index values increased significantly,with lodging rates of 67.5%in 2020–2021 and 59.3%in 2021–2022.Under HD-h,the light transmittance and other indicators in the middle and basal canopy layers were significantly higher than those under HD,and the lodging index decreased to the point that no lodging occurred.Compared with LD,the activities of phenylalanine ammonia-Lyase(PAL),4-coumarate:coenzyme A ligase(4CL),catechol-O-methyltransferase(COMT),and cinnamyl-alcohol dehydrogenase(CAD)in the lignin synthesis pathway were significantly reduced in the culms under HD during the critical period for culm formation,and the relative expression levels of TaPAL,Ta4CL,TaCOMT,and TaCAD were significantly downregulated.However,the activities of lignin synthesis-related enzymes and their gene expression levels were significantly increased under HD-h compared with HD.A partial least squares path modeling analysis found significant positive effects between the canopy light environment,the photosynthetic capacity of the middle and lower leaves of plants,lignin synthesis and accumulation,and lodging resistance in the culms.Thus,under conventional high-density planting,the risk of wheat lodging was significantly higher.Accordingly,the canopy light environment can be optimized by changing the heterogeneity of the population distribution to improve the photosynthetic capacity of the middle and lower leaves of plants,promote lignin accumulation in the culm,and enhance lodging resistance in wheat.These findings provide a basis for understanding the mechanism responsible for the lower mechanical strength of the culm under high-yield wheat cultivation,and a theoretical basis and for developing technical measures to enhance lodging resistance.

Spatial Morphology Evolution Characteristics Analysis of the Resident Population Distribution in Henan, China

The population spatial distribution pattern and its evolving pattern play an important role in regional allocation of social resources and production factors, formulation of regional development plans, construction of a better life society, and promotion of regional economic development. Based on the resident population statistics data of Henan province from 2006 to 2021, with county as the basic study unit, the paper studies the spatial morphology characteristics and its evolution patterns of resident population distribution, by using spatial analysis methods such as population distribution center, standard deviation ellipse, and spatial auto correlation analysis. The results show that: the resident population spatial distribution shows unbalanced state, the population agglomeration areas mainly distribute in the northeast part and north part, where the resident population growth rate is significantly higher than other regions, over time, this trend is gradually becoming significant. The resident population distribution has a trend of centripetal concentration, with the degree and trend of centripetal gradually strengthening. The resident population distribution has obvious directional characteristics, but the significance is not high, the weighted resident population average center is approximately located at (4.13740˚N, 113.8935˚E), and the azimuth of the distribution axis is approximately 11.19˚. The population distribution has obvious agglomeration characteristics, with the built-up areas of Zhengzhou and Luoyang as their centers, where have a significant siphon effect on the surrounding population. The southern and southwestern regions in the province form a relatively stable belt area of Low-Low agglomeration areas.

Relief degree of land surface and its influence on population distribution in China

The relief degree of land surface （RDLS） is an important factor for describing the landform at macro-scales. This study defines a concept for RDLS and applies the concept for population distribution study of the entire country. Based on the concept and macro-scale digital elevation model datum and ARC/INFO software, the RDLS at a 10 km×10 km grid size of China is extracted. This paper depicts systemically the spatial distributions of RDLS through analyzing the ratio structure and altitudinal characters of RDLS in China. The conclusions are drawn as follows： the RDLS in more than 63% of the area is less than one （1） （relative altitude is less than 500 m）, reflecting the fact that most of RDLS in China is low. In general, the RDLS in the west is larger than that in the east and so is the south than that of the north in China. The RDLS decreases with the increase of longitude and latitude and the change of RDLS at the latitudes of 28°N, 35°N, 42°N, as well as at the longitudes of 85°E, 102°E, 115°E could reflect the three major ladders of China. In the vertical direction, the RDLS increases with the increase of altitude. Analysis of the correlation between RDLS and population distribution in China and its regional difference shows that the R2 value between RDLS and population density is 0.91 and RDLS is an important factor influencing the spatial distribution of population. More than 85% of the people in China live in areas where the RDLS is less than one （1）, while the population in areas with RDLS greater than 3 accounts only for 0.57% of the total. The regional difference of correlation between RDLS and population within China is significant and such correlation is significant in Central China and South China and weak in Inner Mongolia and Tibet.

Relief Degree of Land Surface and Population Distribution of Mountainous Areas in China

Evaluation on the population pressure in the mountainous areas is a necessary condition for the protection and good governance. The evaluation depends on accurate population density assessment. Traditional methods used to calculate population density often adopt the administrative region as a scale for statistical analysis. These methods did not consider the effects of the relief degree of land surface(RDLS) on the population distribution. Therefore they cannot accurately reflect the degree of population aggregation, especially in mountainous areas. To explore this issue further, we took the mountainous areas of China as the research area. China has A total area of 666 km2 can be classified as mountainous area,accounting for 69.4% of the country's total landmass. The data used in this research included the digital elevation model(DEM) of China at a scale of 1:1,000,000, National population density raster data, the DEM and the national population density raster data. First, we determined the relief degree of land surface(RDLS). Next, we conducted a correlation analysis between the population distribution and the RDLS using the Statistical Package for Social Science(SPSS). Based on the correlation analysis results and population distribution, this new method was used to revise the provincial population density of themountainous areas. The revised results were used to determine the population pressure of different mountainous areas. Overall, the following results were obtained:(1) The RDLS was low in most mountainous areas(with a value between 0 and 3.5) and exhibited a spatial pattern that followed the physiognomy of China;(2) The relationship between the RDLS and population density were logarithmic, with an R2 value up to 0.798(p<0.05), and the correlation decreased from east to west;(3) The difference between the revised population density(RPD) and the traditional population density(PD) was larger in the southeastern region of China than in the northwestern region;(4) In addition, compared with traditional results, the revised result indicated that the population pressure was larger. Based on these results, the following conclusions were made:(1) the revised method for estimating population density that incorporates the RDLS is reasonable and practical,(2) the potential population pressure in the southeastern mountainous areas is substantial,(3) the characteristics of the terrain in the high mountainous areas are important for the scattered distribution of the population, and(4) the population distribution of mountainous areas in China should be guided by local conditions, such as social, economic, and topographic conditions.

Character and Causes of Population Distribution in Shenyang City,China

Character of population distribution is one of the focuses studied by urban geography. Using the fifth national census data as basic data and using areal interpolation method, this paper analyzes character of urban population dis- tribution of Shenyang City, Northeast China, in terms of three aspects of statistical character, spatial auto-correlation and spatial structure. Furthermore, this research analyzes the factors affecting the population distribution of the city. The main conclusions include: 1) There is an obvious structure character of population distribution in the grid with a grain of 300m, which is appropriate scale when researching population distribution in Shenyang City. 2) Urban population dis- tribution has the character of assembling while population density distribution takes on variability in Shenyang City. 3) Population density distribution shows spatial auto-correlation within 7.36km. Spatial heterogeneity of population density is low. 4) Urban center, population distribution barycenter and population density maximum points separate each other. Population density distribution has multi-cores character. 5) Layout of governments, primary schools, middle schools, colleges, hospitals and marketplaces affects population distribution directly. With the increase of distance to these factors, population density decreases as logarithm.

Population Distribution and Influencing Factors Based on ESDA

Based on the exploratory spatial data analysis （ESDA） technique and geographic information system （GIS） platform, with statistic data of counties in 2005, this paper confirms that there is a large population density gap between counties in 2005 because the Gini coefficient is 0.55. Population distribution does not change a lot during the past decades, and the southeast China is still much more densely populated than the northwest China. The global spa- tial autoeorrelation of population distribution is obvious because Moran＇s I scores 0.42 and local spatial autocorrelation is partly significant. Climate and elevation are still the main natural influ- encing factors. Meanwhile industrial structure and transportation significantly influence population distribution. Different combinations of natural factors have different effects on population distribution. For a long term, climate and terrain factor stability affect population distribution. But its influence will be weakened by progress of technology. Economic development is the main factor that changes population distribution for a short term.

Population distribution, structure and growth condition of Antarctic krill(Euphausia superba Dana) during the austral summer in the Southern Ocean

Antarctic krill （Euphausia superba Dana） was collected using a High Speed Collector and an Isaac-Kidd midwater trawl （IKMT） net during the austral summer of 2007/2008 and 2008/2009 in the circumpolar and Prydz Bay regions of the Southern Ocean, respectively. Combined with the simultaneous recording of environmental factors, spatial distribution, population structure and growth condition of E. superba were studied. The abundance of E. superba in the Weddell Sea was higher than in Prydz Bay. However, the abundance of E. superba in both the Weddell Sea and Prydz Bay was lower than figures reported in previous krill surveys for the same time period. With respect to the total study area, E. superba displayed a normal growing state during the two expeditions. E. superba grew relatively poorly in some stations, which may be due to the late retreat of sea ice or lower chlorophyll a concentrations. The number of juvenile E. superba collected using the High Speed Collector was proportionally greater in stations located at the edge of the sea ice, while adults dominated in long-term non-ice regions. This phenomenon reflects the different distribution pattern between juvenile and adult krill. The population structure of E. superba differed between sea regions, which may affect recruitment.

Population distribution, urban construction and urban management in the process of China urbanization

Along with China＇s urbanization, a series of problems came, such as the rapidly expanding urban population, large-scale urban construction and investment, the financing gap of government＇s investment in construction, and urban management, etc. This article first describes the growth of urban population, the scale and the input of urban construction, and then analyzes the financial revenue and expenditure, and at last argues for the necessity of urban management, and puts forward the research content of urban management.

Research on the Variation of Population Distribution and Its Characteristics Based on Spatial Autocorrelation Method: A Case Study of Poyang Lake Region in Jiangxi Province

According to Statistical Yearbook of Jiangxi Province(2001～2006),We analyze the time-space variation of population distribution of Poyang Lake region from the two points of view.The former is quality of population,which involves culture structure,occupational structure,age structure and sex structure of population.The latter is quantity of population,which only involves the amount of population.Furthermore,we can reveal the internal relations and action mechanism of variation of population distribution by analyzing the regional economic development,population urbanization,land use and ecological landscape of Poyang Lake region.It is important to provide help for region planning,ecological landscape planning and environmental protection by correct understanding the man-land relationship of natural-human ecosystem in Poyang Lake region.

Quantitative Analysis on the Relationship between Population Distribution and Environment Factors in Mountain Area

[Objective] The aim was to analyze the relationship between population distribution and environment factors in mountain area quantitatively.[Method] Taking the contiguous area of Sichuan,Yunnan and Guizhou Province as study object,population density and residential point density were chosen as the indices of population distribution,and the quantitative relationship between population distribution and environment factors (including altitude,topography relief amplitude,land use,road network and river network) in mountain area was analyzed.[Result] Altitude and topography relief amplitude in mountain area had obvious negative correlation with population density and residential point density,and the correlation coefficients with population density were-0.731 and-0.743.In addition,residential points were fewer in the region far from rivers,but there was no obvious correlation between population density and river network density.Residential point density was higher in cultivated land and construction land,and population density had obvious positive correlation with the area proportions of cultivated land and construction land,with the correlation coefficients of 0.895 and 0.726,respectively.Besides,the more distant from road,the smaller residential point density,and there was obvious positive correlation between population density and road network density,with the correlation coefficient of 0.823.[Conclusion] The study could lay a foundation for the further development of spatiality of population data in study region.

Population Distribution of Excited States in Cs Electrodeless Discharge Lamp

We measure the intensity of fluorescence spectral lines of Cs atoms in an electrodeless discharge lamp from visible light to the near-infrared region of 400-100Ohm. To build an excited state Faraday anomalous dispersion optical filter, the population ratios between the excited states are calculated by rate equations and the spontaneous transition probabilities. The electrodeless discharge lamp with populations in the excited states can be used to realize the frequency stabilization reference for lasers at multiwavelength and the excited state Faraday anomalous dispersion optical filter for submarine communication applications in blue-green wavelengths to simplify the system.

Relationship between Physico-Chemical Parameters and the Population Distribution of Fresh Water Snails in Amassoma Community and Niger Delta University Campuses,Bayelsa State,Nigeria

Evaluating the presence of fresh water snails in a location is germane in establishing a snail-borne disease control program.The purpose of the study was to see how physicochemical parameters influenced the population distribution of four fresh water snails(Lymnaea natalensis,Bulinus globosus,Biomphalaria pfeiffer,and Melanoides spp.)in the Amassoma community and Niger Delta University between March,2021 and May 2021.Snails were gathered by plucking and scooping them by hand.Snail was identified using standard pictorial keys.Physicochemical of the water of the snail habitat were measured using standard in-situ apparatus across eight sites Physico chemical measured were temperature,pH,conductivity,BOD,turbidity,salinity,and alkalinity.A total of 258 snails were gathered from the eight(8)different sites.In all sites,Lymnaea natalensis was more abundant.Bulinus globosus,Biomphalaria pfeiffer,and Melanoides spp.were among the other snails discovered.Lymnaea had negative correlation with pH,conductivity,BOD,and alkalinity and a positive correlation with salinity and temperature.Bulinus had a positive relationship with pH,salinity,and conductivity and a negative correlation with temperature,turbidity,BOD,and alkalinity.Biomphalaria had a positive correlation with temperature,pH,salinity,turbidity,and alkalinity Melanoides had positive correlations with Temperature,pH,salinity,BOD,and alkalinity and a negative correlation with turbidity and concentration.The was correlation between snails and snails.The presence of these snails suggests that the Amassoma village and Niger Delta University campuses are potential hotspots for a variety of snail-borne diseases.

Dynamic Assessment of Spatiotemporal Population Distribution Based on Mobile Phone Data: A Case Study in Xining City,China

High-resolution,dynamic assessments of the spatiotemporal distributions of populations are critical for urban planning and disaster management.Mobile phone big data have real-time collection,wide coverage,and high resolution advantages and can thus be used to characterize human activities and population distributions at fne spatiotemporal scales.Based on six days of mobile phone user-location signal(MPLS)data,we assessed the dynamic spatiotemporal distribution of the population of Xining City,Qinghai Province,China.The results show that strong temporal regularity exists in the daily activities of local residents.The spatiotemporal distribution of the local population showed a signifcant downtown-suburban attenuation pattern.Factors such as land use types,holidays,and seasons signifcantly afect the spatiotemporal patterns of the local population.By combining other spatiotemporal trajectory data,high-resolution and dynamic real-time population distribution evaluations based on mobile phone location signals could be better developed and improved for use in urban management and disaster assessment research.

Population distribution and urbanization on both sides of the Hu Huanyong Line:Answering the Premier's question

In late November 2014, while attending a science exhibition on human settlement at the National Museum, Premier Li Keqiang posed a question to society and scientists regard- ing the Hu Huanyong Line, which the media subsequently dubbed ＂the Premier＇s question＂. This increased awareness and interest in the Hu Huanyong Line and launched a lively debate which provoked a variety of views. In an attempt to address the Premier＇s question, this paper firstly reviews the origins of the Hu Huanyong Line, named after the famous population ge- ographer who proposed it in 1935 as part of a wider debate on domestic overpopulation. Using demographic data from ChJna＇s first, fifth and sixth censuses, as well as the ArcGIS platform, we analyze the size, proportion and density of populations in the areas southeast and northwest of the Hu Huanyong Line, showing that urbanization and migration have not changed the pattern of population distribution observed by Hu Huanyong. Based on this, we suggest that the pattern of a dense population southeast of the line and sparse population northwest of the line will not fundamentally change for a relatively long time, nor will the situation of urban agglomerations being mainly found in the southeastern region. We also argue that climate and other physical geographic conditions determine that the Hu Huanyong Line shall remain in place. We believe that the question posed by Premier Li Keqiang is solvable, and that with positive policy guidance and rational spatial organization, the north- western region can achieve more modernization and better quality urbanization, while the same is true for the central region.

Impact of Temporal Population Distribution on Earthquake Loss Estimation:A Case Study on Sylhet,Bangladesh

To estimate human loss in an earthquake-prone area, it is necessary to analyze the role played by the spatiotemporal distribution of the area’s resident population. In order to evaluate earthquake impact, this article focuses on the spatiotemporal distribution of population and five scenario earthquakes that form the basis for loss estimation in the city of Sylhet, Bangladesh. Four temporal contexts(weekday, weekly holiday, the 30 days of Ramadan, and strike days) expand the more typical daytime and nighttime settings in which to examine hazard risk. The population distribution for every 2 hour interval in a day is developed for each type of day. A relationship between the occupancy classes and average space(persons per 100 m^2)is used to distribute people in each building regardless of building locations. A total daytime and nighttime population is obtained for each building and the estimated nighttime population is used to model the population for four temporal scenarios in a year based on different factors and weights. The resulting data are employed to estimate population loss for each of the temporal and earthquake scenarios. This study used building-specific human vulnerability curves developed by the Central American Probabilistic Risk Assessment(CAPRA) to obtain possible loss of life estimates. The results reveal that there is a high positive correlation between the spatiotemporal distribution of population and the potential number of casualties.

Study on distributional characteristics of phytoplankton population in the Bohai Sea and the Yellow Sea in the summer 2015

Marine phytoplankton plays a very important role in marine ecology,environment and global climate change,and it is an indicative organism for measuring water quality.The Bohai Sea and the Yellow Sea in China have unique geographical locations.Therefore,the characteristics of phytoplankton population distribution in the Bohai Sea and the Yellow Sea are of great significance to the study of marine ecology in China.In this work,the pigment data obtained from the Yellow Sea and Bohai Sea in August 2015 were analyzed by HPLC(High-Performance Liquid Chromatography).Then the pigment data were analyzed statistically by the CHEMTAX software,so that the phytoplankton community structure information was obtained.Results show that in summer 2015,from the perspective of sea area,the biomass of phytoplankton in the surface of Bohai Sea is higher than that in the Yellow Sea,while the phytoplankton biomass in the surface of North Yellow Sea is higher than that in the South.From the perspective of dominant species of phytoplankton,the surface waters of the Yellow Sea and Bohai Sea were dominated by diatoms,prymnesiophytes and chlorophytes,accounting for 55.76%,14.56%and 14.55%respectively.Among them,diatoms accounted for the absolute advantage.

Population distribution modelling at fine spatio-temporal scale based on mobile phone data

Population distribution modelling can benefit many different domains,for example,transportation,urban planning,ecology or emergency management.Information about the location and number of people in an affected area is crucial for decision-makers during emergencies and crises.Mobile phone data represents relatively reliable and time accurate information on real-time population distribution,movement and behaviour.In this study,we evaluate the spatio-temporal distribution of population derived from phone data of the selected pilot area(City of Brno,Czech Republic).Analysis is based on the dataset describing the estimated human presence(EHP)with two values-visitors and transiting persons.The temporal change of data is first analysed and further processed using two methodological approaches.First,the dasymetric method is used where the building geometry and technical attributes served as a target layer.Second,the results of building level analysis are transformed into a regular grid zone of both visitors and the general EHP.Resulting spatio-temporal patterns are compared to the census data.Results demonstrate how the proposed building level dasymetric approach can improve the spatial granularity of EHP.Potential use of proposed methodology within selected emergency situations is further discussed.

Spatial Coupling Relationship and Driving Mechanism of Population and Economy in Rural Areas in Qinling-Daba Mountains,China

Addressing the issue of the healthy and coordinated development of the population and economic factors in rural areas will not only help consolidate and expand the achievements of poverty alleviation,but will also lay a foundation for comprehensive rural revitalization.In this paper,the spatial coupling relationship between the population and economic factors in rural areas in the QinlingDaba Mountains,China,is explored to provide a reference for rural revitalization and regional sustainable development in poverty areas.Sixty-eight county units in rural areas in the Qinling-Daba Mountains,as well as the population and economic factors in rural areas,are used to study the spatial coupling relationship between population and economy,as well as the driving mechanism,in rural areas in the Qinling-Daba Mountains from 2010 to 2020.The results show that a population contraction phenomenon occurred in the rural areas in the Qinling-Daba Mountains,and the spatial agglomeration trends of the population and economic factors were consistent.The agglomeration was mainly located in the suburban areas of the municipal area,and the agglomeration degree was significantly higher in these areas than in other areas.In terms of the spatial distribution,the economic development level of the rural areas in the northeastern part of the Qinling-Daba Mountains was generally higher than that in the central and western parts,and the unbalanced trends of the population and economic spatial differentiation in the eastern and western regions were significant.The spatial coupling relationship between the population and economy changed from coordinated development to economic advancement.This was mainly due to the mutual restriction and joint actions of the industrial structure,capital situation,natural environment,policies,and institutional regulations,among which the industrial structure and capital status had significant effects.

A hybrid model for high spatial and temporal resolution population distribution prediction

The accurate prediction of population distribution is crucial for numerous applications,from urban planning to epidemiological modelling.Using one-week data collected from open and multiple sources,including telecommunication activity,weather,point of interest,buildings,roads,and land use in Milan,Italy,we develop a hybrid method combining cellular automata(CA)and long short-term memory(LSTM)to predict population distribution with fine temporal and spatial granularity.Specifically,the convolutional autoencoder and LightGBM are applied to identify missing building types based on the pedestrian shed.The LSTM learns the transition rules of CA and Shapley additive explanations value is used for variable importance analysis.Results demonstrate that the combination of convolutional autoencoder and LightGBM is effective in building type prediction.The proposed model for population distribution prediction outperforms LSTM,the combination of CA and neural network,and the combination of CA and LightGBM by at least 5–10%.A variable importance analysis reveals that temporal variables are the most significant for prediction,followed by spatial and natural variables.The order of hour,housing-related variables,and types of precipitation are the most important variables in each category.

Underground space use of urban built-up areas in the central city of Nanjing:Insight based on a dynamic population distribution

With the expansion of cities and the emergence of various urban problems,urban underground space has been developed as a solution.In China’s urban transition context,there is a need for the development of underground space in urban built-up areas.In this casestudy of the central city of Nanjing,we used spatial analysis and statistical methods to characterize the underground space use of urban built-up areas from a dynamic spatiotemporal perspective.We first analyzed the relationship between the population distribution and the underground space use of the central city of Nanjing based on a Baidu heat map,which can reflect the real-time population distribution,and then,we explored the spatiotemporal characteristics and spatial structure of the underground space use in urban built-up areas.The analysis results provide a reference for planning to improve and optimize the layout of underground space in the central city of Nanjing and,more generally,for the stock-type planning of underground space in urban built-up areas.