Social networks like Facebook, X (Twitter), and LinkedIn provide an interaction and communication environment for users to generate and share content, allowing for the observation of social behaviours in the digital w...Social networks like Facebook, X (Twitter), and LinkedIn provide an interaction and communication environment for users to generate and share content, allowing for the observation of social behaviours in the digital world. These networks can be viewed as a collection of nodes and edges, where users and their interactions are represented as nodes and the connections between them as edges. Understanding the factors that contribute to the formation of these edges is important for studying network structure and processes. This knowledge can be applied to various areas such as identifying communities, recommending friends, and targeting online advertisements. Several factors, including node popularity and friends-of-friends relationships, influence edge formation and network growth. This research focuses on the temporal activity of nodes and its impact on edge formation. Specifically, the study examines how the minimum age of friends-of-friends edges and the average age of all edges connected to potential target nodes influence the formation of network edges. Discrete choice analysis is used to analyse the combined effect of these temporal factors and other well-known attributes like node degree (i.e., the number of connections a node has) and network distance between nodes. The findings reveal that temporal properties have a similar impact as network proximity in predicting the creation of links. By incorporating temporal features into the models, the accuracy of link prediction can be further improved.展开更多
Objective This study employs the Geographically and Temporally Weighted Regression(GTWR)model to assess the impact of meteorological elements and imported cases on dengue fever outbreaks,emphasizing the spatial-tempor...Objective This study employs the Geographically and Temporally Weighted Regression(GTWR)model to assess the impact of meteorological elements and imported cases on dengue fever outbreaks,emphasizing the spatial-temporal variability of these factors in border regions.Methods We conducted a descriptive analysis of dengue fever’s temporal-spatial distribution in Yunnan border areas.Utilizing annual data from 2013 to 2019,with each county in the Yunnan border serving as a spatial unit,we constructed a GTWR model to investigate the determinants of dengue fever and their spatio-temporal heterogeneity in this region.Results The GTWR model,proving more effective than Ordinary Least Squares(OLS)analysis,identified significant spatial and temporal heterogeneity in factors influencing dengue fever’s spread along the Yunnan border.Notably,the GTWR model revealed a substantial variation in the relationship between indigenous dengue fever incidence,meteorological variables,and imported cases across different counties.Conclusion In the Yunnan border areas,local dengue incidence is affected by temperature,humidity,precipitation,wind speed,and imported cases,with these factors’influence exhibiting notable spatial and temporal variation.展开更多
Background: Knowledge of temporal evolution of preeclampsia (PE) in its various aspects is essential in strategies to reduce maternal and perinatal morbidity and mortality. Preeclampsia is a public health problem due ...Background: Knowledge of temporal evolution of preeclampsia (PE) in its various aspects is essential in strategies to reduce maternal and perinatal morbidity and mortality. Preeclampsia is a public health problem due to maternal mortality associated with it worldwide (5.6%). Improving quality of its management is a major challenge in low-income countries where, despite progress made in this field, PE remains a major factor in maternal morbidity and mortality. Objective: To evaluate temporal evolution of frequency, risk factors and complications of PE at the University clinics of Kinshasa (UCK). Methods: Descriptive and cross-sectional study concerning minimum simple size of 119 pregnant women who consulted for antenatal care at the University clinics of Kinshasa from January 2012 to December 2022. Results will be reported as percentage proportion, mean and standard deviation. Comparison of proportion and means between groups will be made using Student’s t-test and Pearson’s chi-square test, respectively. The test will be statistically significant for a p value ≤ less than 0.05. Data will be collected and analysed anonymously and confidentially. Conclusion: This study will allow us to evaluate the effectiveness of different prevention and treatment modalities used over time in management of preeclampsia in our setting.展开更多
The CO_(2)effl ux of branches and leaves plays an important role in ecosystem carbon balance.Using a carbon fl ux system,the effl ux of Larix gmelinii var.principisrupprechtii(Dahurian larch)was investigated in 27 yea...The CO_(2)effl ux of branches and leaves plays an important role in ecosystem carbon balance.Using a carbon fl ux system,the effl ux of Larix gmelinii var.principisrupprechtii(Dahurian larch)was investigated in 27 years(immature),31 years(near-mature),and 47 years(mature)stands at diurnal,seasonal,and spatial scales(direction and height)as well as its connection with environmental factors from May to October 2020.Diurnal variation in effl ux was a single peak,and the maximum occurring between 14:00 and 16:00.Seasonal variation also exhibited a single peak,with the maximum in late July and the minimum in early October.From May to September,effl ux on the south side was the largest among the three stands,and mean values on the south side of 27 year-old,31 year-old,and 47 year-old trees were 0.50,0.97 and 1.05μmol·m^(–2)·s^(–1),respectively.The minimum occurred on the north side.Except for the maximum in July and September in the 27 year-old stand in the middle of the canopy,the maximum effl ux in the upper canopy,and the means in the 27 year-old,31 year-old,and 47 year-old stands were 0.49,0.96 and 1.04μmol·m^(-2)·s^(-1),respectively;the minimum occurred in the lower canopy.Temperatures and relative humidity infl uenced seasonal variations in effl ux.Seasonal variation in temperature sensitivity coeffi cient(Q 10)was opposite that of temperature,increasing with decreasing temperature.At the spatial scale,maximum Q 10 occurred in the mid canopy.With the effl ux and temperature data in diff erent locations,it is possible to better estimate effl ux variations in each stand.展开更多
This study analyzed the spatial-temporal heterogeneity of green development efficiency and its influencing factors in the growing Xuzhou Metropolitan Area for the period 2000–2015.The slacks-based measure(SBM)model,s...This study analyzed the spatial-temporal heterogeneity of green development efficiency and its influencing factors in the growing Xuzhou Metropolitan Area for the period 2000–2015.The slacks-based measure(SBM)model,spatial autocorrelation,and the geographically weighted regression(GWR)model were used to conduct the analysis.The conclusions were as follows:first,the overall efficiency of green development of the Xuzhou Metropolitan Area decreased,the regional differences and spatial agglomeration shrunk and differences within the region were the main contributors to the regional differences of green development efficiency.Second,the counties with high-efficiency green development were distributed along the coast,and along the routes of the Beijing-Shanghai and the Eastern Longhai railways.A developing axis of the high-efficiency counties was the main feature of the spatial pattern for green development efficiency.Third,regarding spatial correlation and green development efficiency,the High-High type counties in the Xuzhou Metropolitan Area formed a centralized distribution corridor along the inter-provincial border areas of Henan and Jiangsu,whereas the Low-Low type counties were concentrated in the external,marginal parts of the metropolitan area.Fourth,the major factors(ranked in decreasing order of impact)influencing green development efficiency were innovation,government regulations,the economic development level,energy consumption,and industrial structure.These factors exerted their influence to varying extents;the influence of the same factor had different effects in different regions and obvious spatial differences were observed for the different regions.展开更多
The degree-day model is one important method to estimate glacier melt, which is based on the specific relationship between glacial melting and the sum of daily mean temperatures above the melting point. According to t...The degree-day model is one important method to estimate glacier melt, which is based on the specific relationship between glacial melting and the sum of daily mean temperatures above the melting point. According to the observation data on the Koxkar Glacier(KG) from 2005 to 2010, we analyzed the temporal and spatial variation of degree-day factors(DDF) and its influential factors. The results indicate that the average value of DDF was 7.2~10.4 mm/(°C·d) on the KG from 2005 to 2010. It showed a decreasing trend between 3,700 m and 4,200 m, and the deceasing trend was more obvious in the upper part of the KG. On a spatial scale, the DDF increased evidently with increasing altitude. The DDF ranged from3.6 to 9.3 mm/(°C·d) at 3,700 m a.s.l., with the average value of 9.3 mm/(°C·d). It varied from 6.9 to 13.0 mm/(°C·d) at4,000 m a.s.l., with the average value of 10.2 mm/(°C·d). During the period of ablation, the fluctuation of DDF was not significant at the lower altitude(3,700 m a.s.l.), but it decreased at the higher altitudes(4,000 m a.s.l. and 4,200 m a.s.l.).The debris changes the transmission of heat, which accelerates the melting of a glacier; and the DDF showed high value.This paper will provide the reference for temporal–spatial parameterization schemes of DDF on Tuomuer glaciers of the Tianshan Mountains.展开更多
The aviation industry has become one of the top ten greenhouse gas emission industries in the world. China’s aviation carbon emissions continue to increase, but the analysis of its influencing factors at the provinci...The aviation industry has become one of the top ten greenhouse gas emission industries in the world. China’s aviation carbon emissions continue to increase, but the analysis of its influencing factors at the provincial level is still incomplete. This paper firstly uses Stochastic Impacts by Regression on Population, Affluence and Technology model(STIRPAT) model to analyze the time series evolution of China’s aviation carbon emissions from 2000 to 2019. Secondly, it uses the Logarithmic Mean Divisia Index(LDMI) model to analyze the influencing characteristics and degree of four factors on China’s aviation carbon emissions, which are air transportation revenue, aviation route structure, air transportation intensity and aviation energy intensity. Thirdly, it determines the various factors’ influencing direction and evolution trend of 31 provinces’ aviation carbon emissions in China(not including Hong Kong, Macao, Taiwan of China due to incomplete data). Finally, it derives the decoupling effort model and analyzes the decoupling relationship and decoupling effort degree between air carbon emissions and air transportation revenue in different provinces. The study found that from 2000 to2019, China’s total aviation carbon emissions continued to grow, while the growth rate of aviation carbon emissions showed a fluctuating downward trend. Air transportation revenue and aviation route structure promote the growth of total aviation carbon emissions, and air transportation intensity and aviation energy intensity have a restraining effect on the growth of total aviation carbon emissions. The scope of negative driving effect of air transportation revenue and air transportation intensity on total aviation carbon emissions in various provinces has increased. While the scope of positive driving influence of aviation route structure on total aviation carbon emissions of various provinces has increased, aviation energy intensity mainly has negative driving influence on total aviation carbon emissions of each province. Overall, the emission reduction trend in the areas to the west and north of the Qinling-Huaihe River Line is obvious. The decoupling mode between air carbon emissions and air transportation revenue in 31 provinces is mainly expansion negative decoupling.The air transportation intensity effect shows strong decoupling efforts in most provinces, the decoupling effort of aviation route structure effect and aviation energy intensity effect is not prominent.展开更多
Phytoplankton and environment factors were investigated in 2015 and phytoplankton functional groups were used to understand their temporal and spatial distribution and their driving factors in Wanfeng Reservoir. Seven...Phytoplankton and environment factors were investigated in 2015 and phytoplankton functional groups were used to understand their temporal and spatial distribution and their driving factors in Wanfeng Reservoir. Seventeen functional groups(B, D, E, F, G, J, Lo, MP, P, S1, T, W1, W2, X1, X2, Xph, Y) were identified based on 34 species. The dominant groups were: J/B/P/D in dry season, X1/J/Xph/G/T in normal season and J in flood season. Phytoplankton abundance ranged from 5.33×10~4 cells/L to 3.65×10~7 cells/L, with the highest value occurring in flood season and lowest in dry season. The vertical profi le of dominant groups showed little differentiation except for P, which dominated surface layers over 20 m as a result of mixing water masses and higher transparency during dry season. However, the surface waters presented higher values of phytoplankton abundance than other layers, possibly because of greater irradiance. The significant explaining variables and their ability to describe the spatial distribution of the phytoplankton community in RDA diff ered seasonally as follows: dry season, NH4-N, NO_3-N, NO_2-N, TN:TP ratio and transparency(SD); normal season, temperature(WT), water depth, TN, NH4-N and NO_3-N; flood season, WT, water depth, NO_3-N and NO_2-N. Furthermore, nitrogen, water temperature, SD and water depth were significant variables explaining the variance of phytoplankton communities when datasets included all samples. The results indicated that water physical conditions and hydrology were important in phytoplankton community dynamics, and nitrogen was more important than phosphorus in modifying phytoplankton communities. Seasonal differences in the relationship between the environment and phytoplankton community should be considered in water quality management.展开更多
Based on the data of six automatic air monitoring stations in Bengbu City,the pollution characteristics and temporal distribution of fine particulate matter PM 2.5 in the air in Bengbu City from 2015 to 2019 were stud...Based on the data of six automatic air monitoring stations in Bengbu City,the pollution characteristics and temporal distribution of fine particulate matter PM 2.5 in the air in Bengbu City from 2015 to 2019 were studied,and the correlation between meteorological factors and PM 2.5 concentration was analyzed.The results showed that from 2015 to 2019,PM 2.5 pollution in Bengbu City was relatively heavy in winter and spring and relatively light in summer and autumn,and PM 2.5 concentration had two peaks during the day and night.Precipitation,relative humidity,wind direction and wind speed had certain effects on PM 2.5 concentration in Bengbu City.The research provides reference for the monitoring,early warning and prevention of PM 2.5 pollution in the city.展开更多
Urbanization research is essential for the sustainable use of regional land resources and ecological environment protection.The expansion process and driving factors of urban construction land at different scales in t...Urbanization research is essential for the sustainable use of regional land resources and ecological environment protection.The expansion process and driving factors of urban construction land at different scales in the middle reaches of the Yellow River(MRYR)have not been comprehensively elucidated.In this study,we explored the distribution pattern of urban construction land on different slope gradients at different scales and analyzed its influencing factors.The main findings were as follows:(1)There has been significant expansion of urban construction land in the MRYR over the past 20 years.Spatial heterogeneity was observed in the regional urban construction land expansion process among different geomorphic regions.(2)The urban construction land in the MRYR was expanded vertically to areas with slopes of>5°,particularly in 2005–2010.Significant slope climbing of urban construction land was observed in the loess hilly-gully and rocky mountain areas.(3)In MRYR,68.45%of the counties were categorized as the slope-climbing types,including 37.38%high-slope-climbing types.(4)The regional population density and economic development level were closely associated with regional urban construction land area variability.(5)The climbing process of regional urban construction can effectively alleviate farmland encroachment and pressure on the regional ecological environment.The urban expansion of the metropolitan distribution areas in the Plain region(such as Xi'an,Taiyuan)had a relatively significant impact on the local carbon storage.展开更多
Ecological land(Eco-land) is a basic resource for human beings to survive, and eco-land use is a strategy, a way to manage the land resource. So, ecologically-sustainable land use is essential for human beings to surv...Ecological land(Eco-land) is a basic resource for human beings to survive, and eco-land use is a strategy, a way to manage the land resource. So, ecologically-sustainable land use is essential for human beings to survive. This paper investigates the spatiotemporal characteristics and mechanisms of urban-rural eco-land using a new and innovative integration way based on eco-land change data in China's Loess Plateau(LP) prefecture level cities and explores factors of eco-land change. The spatial difference characteristic of eco-land among different level cities in the LP is that: small cities > big cities > middle cities. From 2009 to 2016, the eco-land in the LP from the perspective of urban-rural areas has changed significantly. Significant differences of urban-rural eco-land were identified among various urban growth types, and all the cities in the LP were further classified into four types based on eco-land change trend, with type A and B cities identified as the vital zone and major zone. Taking the eco-fragile region Loess Plateau(LP) as an example, our results demonstrated that the migrants to cities in LP could relieve ecological pressures and promote restoration of ecological vegetation. We have demonstrated that urbanization and the influence of government policy can be discerned through the quantification of the spatial-temporal change of eco-land and suggest that combining both urban and rural eco-land can support more effective land use decisions and provide theoretical basis for the practical application of urban planning, policy-making and sustainable development. What's more, governments should strive to population mobility and restore vegetation to sustain this fragile ecological environment.展开更多
Set-nets are common alongshore fishing gear used in Haizhou Bay, which rely on flow to catch fish. The catch per unit effort(CPUE) of set-net is affected by spatial-temporal and environmental factors but no research h...Set-nets are common alongshore fishing gear used in Haizhou Bay, which rely on flow to catch fish. The catch per unit effort(CPUE) of set-net is affected by spatial-temporal and environmental factors but no research has been conducted on this subject. In this study, we used generalized additive models(GAMs) to explore the influence of spatial-temporal and environmental factors on CPUEs of species aggregated, small yellow croaker(Larimichthys polyactis), and octopus(Octopus variabilis) based on logbooks investigations conducted at 4 stations in an alongshore area of Haizhou Bay from 2011 to 2012. The results showed that all CPUEs exhibited significant spatial-temporal differences at various scales. Aggregated CPUE was high when the sea surface temperature(SST) was 15-18℃ and 20-23℃, which was mainly determined by life history traits of the octopus and small yellow croaker(optimal SSTs 14-17℃ and 19-24℃, respectively). Chlorophyll-a concentration had significant influences on the aggregated, small yellow croaker and octopus CPUEs at optimal ranges of 3.8-6.2 mg m^(-3), 4.2-4.8 mg m^(-3) and 4.5-5.5 mg m^(-3), respectively. Flow through the net had positive relationships with CPUEs. The approximate logarithmic trends in regression curves had a critical point of 2.5 Mm^3 d^(-1), which was the dividing point that differentiated whether the major factor affecting CPUEs was the flow velocity or the fishery resource. Our results from this study will help guide fishery production and improve catch rate of set-net fishing in Haizhou Bay.展开更多
Emission factor is a measure of pollution intensities caused by economic activities, which can be used to assess potential for pollution reduection. With the emission factors derived based on relatively few datu point...Emission factor is a measure of pollution intensities caused by economic activities, which can be used to assess potential for pollution reduection. With the emission factors derived based on relatively few datu points or based on data collected from a specfic region, one can predict the total environmental pollution levels for the drire economy or for another region once the total leve of economic actvities of the concemed economy or region is known or prescribed. Moreover,research on emission factors can not only guide the decision-making process in choosing the best environmental protection strategy, but also be used as indicators. for the assessment and comparison of the environmentally sound development. In this paper, emission factors based on output and employment in different periods,provinces and industries are calculated, based on which temporal and spatial analyses of emission factors are carried out. Obvious declining trends of emission factors both by provinces and industries are declared, and the regional differentiation by provinces and industries is also verified.展开更多
The characteristics of temporal and spatial distribution of tropical cyclone frequencies over the South China Sea areas and its affecting factors in the past 50yrs are analyzed based on typhoon data that provided by C...The characteristics of temporal and spatial distribution of tropical cyclone frequencies over the South China Sea areas and its affecting factors in the past 50yrs are analyzed based on typhoon data that provided by CMA and Simple Ocean Data Assimilation （SODA）. The results show that the tropical cyclone frequencies from June to October show concentrated geographic distribution, for they mainIy distribute over the SCS area from 15 - 20°N. The characteristics present significant interdecadal changes. The impact of oceanic factors on the tropical cyclone frequencies in the SCS area is mainly realized by La Nina and La Nifia-like events before 1975 but mainly by E1 Nino and E1 Nifio-like events after 1975.展开更多
In the context of territorial spatial planning,the overall coordinated protection has become a consensus in the field of cultural heritage protection,and the study on the spatial and temporal pattern of trans-regional...In the context of territorial spatial planning,the overall coordinated protection has become a consensus in the field of cultural heritage protection,and the study on the spatial and temporal pattern of trans-regional cultural heritage is of great significance to the overall protection.Based on the cultural relics protection units in Jingzhou area of national great site protection,the temporal and spatial distribution characteristics and influencing factors of cultural heritage resources were studied with the help of ArcGIS.The data show that on the whole,the cultural heritage in Jingzhou area of national great site protection presented the time series of “a large span,more at two ends” and the spatial distribution pattern of “one main,two secondary and three cores”.Cultural heritage in different historical periods had the characteristics of differentiated regional aggregation.The formation of the spatial pattern of different types of cultural heritage was closely related to the local historical and cultural background.Cultural heritage was affected by rivers,terrain,transportation,land,culture and other factors.It was mainly distributed along rivers in areas with little topographic fluctuation and low altitudes.The development and construction of cultural heritage sites were weak,and the ecological foundation was poor.However,the traffic accessibility was good,and the cultural heritage was deep.The research results are expected to provide a scientific basis for guiding the large site protection area to strengthen the integrated protection of cultural resources.展开更多
Daily precipitation amounts from 1961 to 2005 in 35 observation stations in Liaoning Province were selected in order to study the temporal and spatial distribution of extreme precipitation events.By dint of EOF,REOF,m...Daily precipitation amounts from 1961 to 2005 in 35 observation stations in Liaoning Province were selected in order to study the temporal and spatial distribution of extreme precipitation events.By dint of EOF,REOF,mean-square-error and other ways,the changes in different regions of extreme precipitation and distribution were reflected.The analysis showed that,extreme precipitation in Liaoning Province could be divided into three areas,which were western Liaoning mountains and parts of northern areas,eastern Liaoning mountainous,near-coastal areas of Liaohe River Plain.In the relatively large precipitation areas,extreme precipitation threshold was also higher,and vice versa.The lower frequency of extreme precipitation events had a greater contribution to total precipitation;extreme precipitation,total precipitation and total rain days had the greatest changes in the summer,and the least changes in the winter;number of days of extreme precipitation changes in each season were not great;the change of extreme precipitation was not obvious in the long term.展开更多
The comprehensive carrying capacity of urban land can reflect the re- source level, economic scale, social development and environmental pressure of ur- ban land carrying. The assessment indicator system of urban land...The comprehensive carrying capacity of urban land can reflect the re- source level, economic scale, social development and environmental pressure of ur- ban land carrying. The assessment indicator system of urban land comprehensive carrying capacity was constructed from the 4 aspects of resource, economy, society, environment, and principal component analysis and cluster analysis were used to evaluate the urban land comprehensive carrying capacity of Guangxi and the 14 cities in 2005-2014, and analyzed its spatial and temporal characteristics as well as the driving forces, with the aim to provide references for improving the urban land comprehensive carrying capacity. The results showed that, the overall urban land comprehensive carrying capacity in Guangxi increased in 2005-2014, and there were significant differences in the land comprehensive carrying capacities among the cities in Guangxi in 2005-2014, in which Liuzhou, Guilin, Nanning belonged to the regions with the highest carrying capacity, while Beihai, Yulin, Wutong belonged to the regions with high carrying capacity, and the carrying capacities of the other cities changed with the changes of time. The economic development degree was an important factor influencing urban land comprehensive carrying capacity, but could not directly represent the urban land comprehensive carrying capacity level.展开更多
Nitrogen, phosphorus, and potassium balances for agroecosystems in China from 1993 to 2001 were calculated at national and provincial levels using statistical data and related parameters, and their spatial and tempora...Nitrogen, phosphorus, and potassium balances for agroecosystems in China from 1993 to 2001 were calculated at national and provincial levels using statistical data and related parameters, and their spatial and temporal variabilities were analyzed with GIS to estimate the potential impacts of nutrient N, P and K surpluses or deficits to soil, water and air. At the national scale, the N and P balances from 1993 to 2001 showed a surplus, with the nitrogen surplus remaining relatively stable from 1997—2001. Although during this period the P surplus pattern was similar to N, it had smaller values and kept increasing as the use of phosphate fertilizer increased year by year. However, K was deficient from 1993 to 2001 even though from 1999 to 2001 the K deficit decreased. The spatial analysis revealed higher N surpluses in the more developed southeastern provinces and lowest in the western and northern provinces where there was less chemical fertilizer input. The serious K deficit mainly occurred in Shanghai and Beijing municipalities, Jiangsu, Zhejiang and Hubei provinces, and Xinjiang autonomous regions. For the years 1992, 1996 and 2001, N surpluses and K deficits had significant positive spatial correlations with per capita gross domestic product (GDP), per capita gross industrial output value, and per capita net income of rural households. This showed that the level of economic development played an important role on nutrient balances in the agroecosystems.展开更多
Aim: To investigate the spatial and temporal expression of germ cell nuclear factor (GCNF) in mouse and rat epididymis during postnatal period. Methods: The epididymal sections from different postnatal days were stain...Aim: To investigate the spatial and temporal expression of germ cell nuclear factor (GCNF) in mouse and rat epididymis during postnatal period. Methods: The epididymal sections from different postnatal days were stained for GCNF by the indirect immunofluorescence technique and digital photographs were taken by a Carl Zeiss confocal microscope. Results: GCNF was first detected on day 12 in mouse epididymis and day 14 in rat epididymis. The highest expression of GCNF was observed on day 35 in both mouse and rat epididymis. In adults, GCNF exhibited a region-specific expression pattern, i.e., it was expressed predominantly in the initial segment, caput and proximal corpus of rat epididymis and was abundant in the proximal corpus of mouse epididymis. GCNF could be found in the nuclei of the principal, apical, narrow, clear and halo cells. Conclusion: GCNF may play an important role in epididymal differentiation and development and in sperm maturation.展开更多
Quantitative distribution of planktonic amphipoda in the East China Sea is analyzed and the relation with environmental factors and mackerel and scad fishing grounds is studied. The result shows that the characteristi...Quantitative distribution of planktonic amphipoda in the East China Sea is analyzed and the relation with environmental factors and mackerel and scad fishing grounds is studied. The result shows that the characteristic of biomass is great seasonal and interannual variety during the passing three decades. The distribution of planktonic amphipoda basically reflects the movement, decay and intensification of the different water systems in the survey area.展开更多
文摘Social networks like Facebook, X (Twitter), and LinkedIn provide an interaction and communication environment for users to generate and share content, allowing for the observation of social behaviours in the digital world. These networks can be viewed as a collection of nodes and edges, where users and their interactions are represented as nodes and the connections between them as edges. Understanding the factors that contribute to the formation of these edges is important for studying network structure and processes. This knowledge can be applied to various areas such as identifying communities, recommending friends, and targeting online advertisements. Several factors, including node popularity and friends-of-friends relationships, influence edge formation and network growth. This research focuses on the temporal activity of nodes and its impact on edge formation. Specifically, the study examines how the minimum age of friends-of-friends edges and the average age of all edges connected to potential target nodes influence the formation of network edges. Discrete choice analysis is used to analyse the combined effect of these temporal factors and other well-known attributes like node degree (i.e., the number of connections a node has) and network distance between nodes. The findings reveal that temporal properties have a similar impact as network proximity in predicting the creation of links. By incorporating temporal features into the models, the accuracy of link prediction can be further improved.
基金supported by National Science and Technology Infrastructure Platform National Population and Health Science Data Sharing Service Platform Public Health Science Data Center[NCMI-ZB01N-201905]。
文摘Objective This study employs the Geographically and Temporally Weighted Regression(GTWR)model to assess the impact of meteorological elements and imported cases on dengue fever outbreaks,emphasizing the spatial-temporal variability of these factors in border regions.Methods We conducted a descriptive analysis of dengue fever’s temporal-spatial distribution in Yunnan border areas.Utilizing annual data from 2013 to 2019,with each county in the Yunnan border serving as a spatial unit,we constructed a GTWR model to investigate the determinants of dengue fever and their spatio-temporal heterogeneity in this region.Results The GTWR model,proving more effective than Ordinary Least Squares(OLS)analysis,identified significant spatial and temporal heterogeneity in factors influencing dengue fever’s spread along the Yunnan border.Notably,the GTWR model revealed a substantial variation in the relationship between indigenous dengue fever incidence,meteorological variables,and imported cases across different counties.Conclusion In the Yunnan border areas,local dengue incidence is affected by temperature,humidity,precipitation,wind speed,and imported cases,with these factors’influence exhibiting notable spatial and temporal variation.
文摘Background: Knowledge of temporal evolution of preeclampsia (PE) in its various aspects is essential in strategies to reduce maternal and perinatal morbidity and mortality. Preeclampsia is a public health problem due to maternal mortality associated with it worldwide (5.6%). Improving quality of its management is a major challenge in low-income countries where, despite progress made in this field, PE remains a major factor in maternal morbidity and mortality. Objective: To evaluate temporal evolution of frequency, risk factors and complications of PE at the University clinics of Kinshasa (UCK). Methods: Descriptive and cross-sectional study concerning minimum simple size of 119 pregnant women who consulted for antenatal care at the University clinics of Kinshasa from January 2012 to December 2022. Results will be reported as percentage proportion, mean and standard deviation. Comparison of proportion and means between groups will be made using Student’s t-test and Pearson’s chi-square test, respectively. The test will be statistically significant for a p value ≤ less than 0.05. Data will be collected and analysed anonymously and confidentially. Conclusion: This study will allow us to evaluate the effectiveness of different prevention and treatment modalities used over time in management of preeclampsia in our setting.
基金supported by the National Natural Science Foundation of China(No.31870387),China Scholarship Council.
文摘The CO_(2)effl ux of branches and leaves plays an important role in ecosystem carbon balance.Using a carbon fl ux system,the effl ux of Larix gmelinii var.principisrupprechtii(Dahurian larch)was investigated in 27 years(immature),31 years(near-mature),and 47 years(mature)stands at diurnal,seasonal,and spatial scales(direction and height)as well as its connection with environmental factors from May to October 2020.Diurnal variation in effl ux was a single peak,and the maximum occurring between 14:00 and 16:00.Seasonal variation also exhibited a single peak,with the maximum in late July and the minimum in early October.From May to September,effl ux on the south side was the largest among the three stands,and mean values on the south side of 27 year-old,31 year-old,and 47 year-old trees were 0.50,0.97 and 1.05μmol·m^(–2)·s^(–1),respectively.The minimum occurred on the north side.Except for the maximum in July and September in the 27 year-old stand in the middle of the canopy,the maximum effl ux in the upper canopy,and the means in the 27 year-old,31 year-old,and 47 year-old stands were 0.49,0.96 and 1.04μmol·m^(-2)·s^(-1),respectively;the minimum occurred in the lower canopy.Temperatures and relative humidity infl uenced seasonal variations in effl ux.Seasonal variation in temperature sensitivity coeffi cient(Q 10)was opposite that of temperature,increasing with decreasing temperature.At the spatial scale,maximum Q 10 occurred in the mid canopy.With the effl ux and temperature data in diff erent locations,it is possible to better estimate effl ux variations in each stand.
基金Under the auspices of the National Natural Science Foundation of China(No.41671123,41971158,41671122)Major Project of Philosophy and Social Science Research of Jiangsu Universities(No.2018SJZDA010).
文摘This study analyzed the spatial-temporal heterogeneity of green development efficiency and its influencing factors in the growing Xuzhou Metropolitan Area for the period 2000–2015.The slacks-based measure(SBM)model,spatial autocorrelation,and the geographically weighted regression(GWR)model were used to conduct the analysis.The conclusions were as follows:first,the overall efficiency of green development of the Xuzhou Metropolitan Area decreased,the regional differences and spatial agglomeration shrunk and differences within the region were the main contributors to the regional differences of green development efficiency.Second,the counties with high-efficiency green development were distributed along the coast,and along the routes of the Beijing-Shanghai and the Eastern Longhai railways.A developing axis of the high-efficiency counties was the main feature of the spatial pattern for green development efficiency.Third,regarding spatial correlation and green development efficiency,the High-High type counties in the Xuzhou Metropolitan Area formed a centralized distribution corridor along the inter-provincial border areas of Henan and Jiangsu,whereas the Low-Low type counties were concentrated in the external,marginal parts of the metropolitan area.Fourth,the major factors(ranked in decreasing order of impact)influencing green development efficiency were innovation,government regulations,the economic development level,energy consumption,and industrial structure.These factors exerted their influence to varying extents;the influence of the same factor had different effects in different regions and obvious spatial differences were observed for the different regions.
基金supported by the National Natural Science Foundation of China (41501073, 41471060, 41421061)the project of State Key Laboratory of Cryospheric Science (SKLCS-ZZ-2017)China Postdoctoral Science Foundation (2015M580893, 2016T90966)
文摘The degree-day model is one important method to estimate glacier melt, which is based on the specific relationship between glacial melting and the sum of daily mean temperatures above the melting point. According to the observation data on the Koxkar Glacier(KG) from 2005 to 2010, we analyzed the temporal and spatial variation of degree-day factors(DDF) and its influential factors. The results indicate that the average value of DDF was 7.2~10.4 mm/(°C·d) on the KG from 2005 to 2010. It showed a decreasing trend between 3,700 m and 4,200 m, and the deceasing trend was more obvious in the upper part of the KG. On a spatial scale, the DDF increased evidently with increasing altitude. The DDF ranged from3.6 to 9.3 mm/(°C·d) at 3,700 m a.s.l., with the average value of 9.3 mm/(°C·d). It varied from 6.9 to 13.0 mm/(°C·d) at4,000 m a.s.l., with the average value of 10.2 mm/(°C·d). During the period of ablation, the fluctuation of DDF was not significant at the lower altitude(3,700 m a.s.l.), but it decreased at the higher altitudes(4,000 m a.s.l. and 4,200 m a.s.l.).The debris changes the transmission of heat, which accelerates the melting of a glacier; and the DDF showed high value.This paper will provide the reference for temporal–spatial parameterization schemes of DDF on Tuomuer glaciers of the Tianshan Mountains.
基金Under the auspices of the National Natural Science Foundation of China(No.42071266)the Third Batch of Hebei Youth Top Talent ProjectNatural Science Foundation of Hebei Province(No.D2021205003)。
文摘The aviation industry has become one of the top ten greenhouse gas emission industries in the world. China’s aviation carbon emissions continue to increase, but the analysis of its influencing factors at the provincial level is still incomplete. This paper firstly uses Stochastic Impacts by Regression on Population, Affluence and Technology model(STIRPAT) model to analyze the time series evolution of China’s aviation carbon emissions from 2000 to 2019. Secondly, it uses the Logarithmic Mean Divisia Index(LDMI) model to analyze the influencing characteristics and degree of four factors on China’s aviation carbon emissions, which are air transportation revenue, aviation route structure, air transportation intensity and aviation energy intensity. Thirdly, it determines the various factors’ influencing direction and evolution trend of 31 provinces’ aviation carbon emissions in China(not including Hong Kong, Macao, Taiwan of China due to incomplete data). Finally, it derives the decoupling effort model and analyzes the decoupling relationship and decoupling effort degree between air carbon emissions and air transportation revenue in different provinces. The study found that from 2000 to2019, China’s total aviation carbon emissions continued to grow, while the growth rate of aviation carbon emissions showed a fluctuating downward trend. Air transportation revenue and aviation route structure promote the growth of total aviation carbon emissions, and air transportation intensity and aviation energy intensity have a restraining effect on the growth of total aviation carbon emissions. The scope of negative driving effect of air transportation revenue and air transportation intensity on total aviation carbon emissions in various provinces has increased. While the scope of positive driving influence of aviation route structure on total aviation carbon emissions of various provinces has increased, aviation energy intensity mainly has negative driving influence on total aviation carbon emissions of each province. Overall, the emission reduction trend in the areas to the west and north of the Qinling-Huaihe River Line is obvious. The decoupling mode between air carbon emissions and air transportation revenue in 31 provinces is mainly expansion negative decoupling.The air transportation intensity effect shows strong decoupling efforts in most provinces, the decoupling effort of aviation route structure effect and aviation energy intensity effect is not prominent.
基金Supported by the Department of Science and Technology of Guizhou Province(Nos.[2014]7001,[2015]2001,[2015]10)the Water Resources Department of Guizhou Province(No.KT201401)
文摘Phytoplankton and environment factors were investigated in 2015 and phytoplankton functional groups were used to understand their temporal and spatial distribution and their driving factors in Wanfeng Reservoir. Seventeen functional groups(B, D, E, F, G, J, Lo, MP, P, S1, T, W1, W2, X1, X2, Xph, Y) were identified based on 34 species. The dominant groups were: J/B/P/D in dry season, X1/J/Xph/G/T in normal season and J in flood season. Phytoplankton abundance ranged from 5.33×10~4 cells/L to 3.65×10~7 cells/L, with the highest value occurring in flood season and lowest in dry season. The vertical profi le of dominant groups showed little differentiation except for P, which dominated surface layers over 20 m as a result of mixing water masses and higher transparency during dry season. However, the surface waters presented higher values of phytoplankton abundance than other layers, possibly because of greater irradiance. The significant explaining variables and their ability to describe the spatial distribution of the phytoplankton community in RDA diff ered seasonally as follows: dry season, NH4-N, NO_3-N, NO_2-N, TN:TP ratio and transparency(SD); normal season, temperature(WT), water depth, TN, NH4-N and NO_3-N; flood season, WT, water depth, NO_3-N and NO_2-N. Furthermore, nitrogen, water temperature, SD and water depth were significant variables explaining the variance of phytoplankton communities when datasets included all samples. The results indicated that water physical conditions and hydrology were important in phytoplankton community dynamics, and nitrogen was more important than phosphorus in modifying phytoplankton communities. Seasonal differences in the relationship between the environment and phytoplankton community should be considered in water quality management.
文摘Based on the data of six automatic air monitoring stations in Bengbu City,the pollution characteristics and temporal distribution of fine particulate matter PM 2.5 in the air in Bengbu City from 2015 to 2019 were studied,and the correlation between meteorological factors and PM 2.5 concentration was analyzed.The results showed that from 2015 to 2019,PM 2.5 pollution in Bengbu City was relatively heavy in winter and spring and relatively light in summer and autumn,and PM 2.5 concentration had two peaks during the day and night.Precipitation,relative humidity,wind direction and wind speed had certain effects on PM 2.5 concentration in Bengbu City.The research provides reference for the monitoring,early warning and prevention of PM 2.5 pollution in the city.
基金supported by Fundamental Research Program of Shanxi Province[Grant No.202303021221154]the Project of Shanxi Province Graduate Education and Teaching Reform[2022YJJG48]。
文摘Urbanization research is essential for the sustainable use of regional land resources and ecological environment protection.The expansion process and driving factors of urban construction land at different scales in the middle reaches of the Yellow River(MRYR)have not been comprehensively elucidated.In this study,we explored the distribution pattern of urban construction land on different slope gradients at different scales and analyzed its influencing factors.The main findings were as follows:(1)There has been significant expansion of urban construction land in the MRYR over the past 20 years.Spatial heterogeneity was observed in the regional urban construction land expansion process among different geomorphic regions.(2)The urban construction land in the MRYR was expanded vertically to areas with slopes of>5°,particularly in 2005–2010.Significant slope climbing of urban construction land was observed in the loess hilly-gully and rocky mountain areas.(3)In MRYR,68.45%of the counties were categorized as the slope-climbing types,including 37.38%high-slope-climbing types.(4)The regional population density and economic development level were closely associated with regional urban construction land area variability.(5)The climbing process of regional urban construction can effectively alleviate farmland encroachment and pressure on the regional ecological environment.The urban expansion of the metropolitan distribution areas in the Plain region(such as Xi'an,Taiyuan)had a relatively significant impact on the local carbon storage.
基金funded by the National Key Research and Development Program of China (Grant No.2017YFC0504701)National Natural Science Foundation of China (Grant Nos.41130748 and 41471143)the National Social Science Foundation of China (Grant No 15ZDA021)
文摘Ecological land(Eco-land) is a basic resource for human beings to survive, and eco-land use is a strategy, a way to manage the land resource. So, ecologically-sustainable land use is essential for human beings to survive. This paper investigates the spatiotemporal characteristics and mechanisms of urban-rural eco-land using a new and innovative integration way based on eco-land change data in China's Loess Plateau(LP) prefecture level cities and explores factors of eco-land change. The spatial difference characteristic of eco-land among different level cities in the LP is that: small cities > big cities > middle cities. From 2009 to 2016, the eco-land in the LP from the perspective of urban-rural areas has changed significantly. Significant differences of urban-rural eco-land were identified among various urban growth types, and all the cities in the LP were further classified into four types based on eco-land change trend, with type A and B cities identified as the vital zone and major zone. Taking the eco-fragile region Loess Plateau(LP) as an example, our results demonstrated that the migrants to cities in LP could relieve ecological pressures and promote restoration of ecological vegetation. We have demonstrated that urbanization and the influence of government policy can be discerned through the quantification of the spatial-temporal change of eco-land and suggest that combining both urban and rural eco-land can support more effective land use decisions and provide theoretical basis for the practical application of urban planning, policy-making and sustainable development. What's more, governments should strive to population mobility and restore vegetation to sustain this fragile ecological environment.
基金funded through the Special Fund for Agro-Scientific Research in the Public Interestthe Special Public Welfare Industry (agriculture) Research-Research and Demonstration of Fisheries Fishing Technology and Fishing Gear (No. 201203018)the National Natural Science Foundation of China (No. 31402350)
文摘Set-nets are common alongshore fishing gear used in Haizhou Bay, which rely on flow to catch fish. The catch per unit effort(CPUE) of set-net is affected by spatial-temporal and environmental factors but no research has been conducted on this subject. In this study, we used generalized additive models(GAMs) to explore the influence of spatial-temporal and environmental factors on CPUEs of species aggregated, small yellow croaker(Larimichthys polyactis), and octopus(Octopus variabilis) based on logbooks investigations conducted at 4 stations in an alongshore area of Haizhou Bay from 2011 to 2012. The results showed that all CPUEs exhibited significant spatial-temporal differences at various scales. Aggregated CPUE was high when the sea surface temperature(SST) was 15-18℃ and 20-23℃, which was mainly determined by life history traits of the octopus and small yellow croaker(optimal SSTs 14-17℃ and 19-24℃, respectively). Chlorophyll-a concentration had significant influences on the aggregated, small yellow croaker and octopus CPUEs at optimal ranges of 3.8-6.2 mg m^(-3), 4.2-4.8 mg m^(-3) and 4.5-5.5 mg m^(-3), respectively. Flow through the net had positive relationships with CPUEs. The approximate logarithmic trends in regression curves had a critical point of 2.5 Mm^3 d^(-1), which was the dividing point that differentiated whether the major factor affecting CPUEs was the flow velocity or the fishery resource. Our results from this study will help guide fishery production and improve catch rate of set-net fishing in Haizhou Bay.
文摘Emission factor is a measure of pollution intensities caused by economic activities, which can be used to assess potential for pollution reduection. With the emission factors derived based on relatively few datu points or based on data collected from a specfic region, one can predict the total environmental pollution levels for the drire economy or for another region once the total leve of economic actvities of the concemed economy or region is known or prescribed. Moreover,research on emission factors can not only guide the decision-making process in choosing the best environmental protection strategy, but also be used as indicators. for the assessment and comparison of the environmentally sound development. In this paper, emission factors based on output and employment in different periods,provinces and industries are calculated, based on which temporal and spatial analyses of emission factors are carried out. Obvious declining trends of emission factors both by provinces and industries are declared, and the regional differentiation by provinces and industries is also verified.
基金Research on Techniques of Predicting the Prospects of Drought and Flood Years inGuangdong – a project of the Science and Technology Plan of Guangdong Province (2005B32601007)Experiments with the Coupling between Typhoons, Waves and Storm Surges and Pre-estimation of Typhoon-inflicted Dagames, a project of the Research Fund for Tropical Oceanic and Meteorological Science
文摘The characteristics of temporal and spatial distribution of tropical cyclone frequencies over the South China Sea areas and its affecting factors in the past 50yrs are analyzed based on typhoon data that provided by CMA and Simple Ocean Data Assimilation （SODA）. The results show that the tropical cyclone frequencies from June to October show concentrated geographic distribution, for they mainIy distribute over the SCS area from 15 - 20°N. The characteristics present significant interdecadal changes. The impact of oceanic factors on the tropical cyclone frequencies in the SCS area is mainly realized by La Nina and La Nifia-like events before 1975 but mainly by E1 Nino and E1 Nifio-like events after 1975.
基金Sponsored by the Project for the Philosophy and Social Science Research of Hubei Provincial Department of Education in 2021 (21Q049)Innovation and Entrepreneurship Project for University Students of Changjiang University in 2021 (Yz2021325)。
文摘In the context of territorial spatial planning,the overall coordinated protection has become a consensus in the field of cultural heritage protection,and the study on the spatial and temporal pattern of trans-regional cultural heritage is of great significance to the overall protection.Based on the cultural relics protection units in Jingzhou area of national great site protection,the temporal and spatial distribution characteristics and influencing factors of cultural heritage resources were studied with the help of ArcGIS.The data show that on the whole,the cultural heritage in Jingzhou area of national great site protection presented the time series of “a large span,more at two ends” and the spatial distribution pattern of “one main,two secondary and three cores”.Cultural heritage in different historical periods had the characteristics of differentiated regional aggregation.The formation of the spatial pattern of different types of cultural heritage was closely related to the local historical and cultural background.Cultural heritage was affected by rivers,terrain,transportation,land,culture and other factors.It was mainly distributed along rivers in areas with little topographic fluctuation and low altitudes.The development and construction of cultural heritage sites were weak,and the ecological foundation was poor.However,the traffic accessibility was good,and the cultural heritage was deep.The research results are expected to provide a scientific basis for guiding the large site protection area to strengthen the integrated protection of cultural resources.
文摘Daily precipitation amounts from 1961 to 2005 in 35 observation stations in Liaoning Province were selected in order to study the temporal and spatial distribution of extreme precipitation events.By dint of EOF,REOF,mean-square-error and other ways,the changes in different regions of extreme precipitation and distribution were reflected.The analysis showed that,extreme precipitation in Liaoning Province could be divided into three areas,which were western Liaoning mountains and parts of northern areas,eastern Liaoning mountainous,near-coastal areas of Liaohe River Plain.In the relatively large precipitation areas,extreme precipitation threshold was also higher,and vice versa.The lower frequency of extreme precipitation events had a greater contribution to total precipitation;extreme precipitation,total precipitation and total rain days had the greatest changes in the summer,and the least changes in the winter;number of days of extreme precipitation changes in each season were not great;the change of extreme precipitation was not obvious in the long term.
基金Supported by the Open Bidding Projects of the Office of Land and Resources of the Guangxi Zhuang Autonomous Region(GXZC2015-G3-0575-GTZB)~~
文摘The comprehensive carrying capacity of urban land can reflect the re- source level, economic scale, social development and environmental pressure of ur- ban land carrying. The assessment indicator system of urban land comprehensive carrying capacity was constructed from the 4 aspects of resource, economy, society, environment, and principal component analysis and cluster analysis were used to evaluate the urban land comprehensive carrying capacity of Guangxi and the 14 cities in 2005-2014, and analyzed its spatial and temporal characteristics as well as the driving forces, with the aim to provide references for improving the urban land comprehensive carrying capacity. The results showed that, the overall urban land comprehensive carrying capacity in Guangxi increased in 2005-2014, and there were significant differences in the land comprehensive carrying capacities among the cities in Guangxi in 2005-2014, in which Liuzhou, Guilin, Nanning belonged to the regions with the highest carrying capacity, while Beihai, Yulin, Wutong belonged to the regions with high carrying capacity, and the carrying capacities of the other cities changed with the changes of time. The economic development degree was an important factor influencing urban land comprehensive carrying capacity, but could not directly represent the urban land comprehensive carrying capacity level.
基金1Project supported by the Knowledge Innovation Program of Chinese Academy of Sciences (No. KZCX2-413).
文摘Nitrogen, phosphorus, and potassium balances for agroecosystems in China from 1993 to 2001 were calculated at national and provincial levels using statistical data and related parameters, and their spatial and temporal variabilities were analyzed with GIS to estimate the potential impacts of nutrient N, P and K surpluses or deficits to soil, water and air. At the national scale, the N and P balances from 1993 to 2001 showed a surplus, with the nitrogen surplus remaining relatively stable from 1997—2001. Although during this period the P surplus pattern was similar to N, it had smaller values and kept increasing as the use of phosphate fertilizer increased year by year. However, K was deficient from 1993 to 2001 even though from 1999 to 2001 the K deficit decreased. The spatial analysis revealed higher N surpluses in the more developed southeastern provinces and lowest in the western and northern provinces where there was less chemical fertilizer input. The serious K deficit mainly occurred in Shanghai and Beijing municipalities, Jiangsu, Zhejiang and Hubei provinces, and Xinjiang autonomous regions. For the years 1992, 1996 and 2001, N surpluses and K deficits had significant positive spatial correlations with per capita gross domestic product (GDP), per capita gross industrial output value, and per capita net income of rural households. This showed that the level of economic development played an important role on nutrient balances in the agroecosystems.
文摘Aim: To investigate the spatial and temporal expression of germ cell nuclear factor (GCNF) in mouse and rat epididymis during postnatal period. Methods: The epididymal sections from different postnatal days were stained for GCNF by the indirect immunofluorescence technique and digital photographs were taken by a Carl Zeiss confocal microscope. Results: GCNF was first detected on day 12 in mouse epididymis and day 14 in rat epididymis. The highest expression of GCNF was observed on day 35 in both mouse and rat epididymis. In adults, GCNF exhibited a region-specific expression pattern, i.e., it was expressed predominantly in the initial segment, caput and proximal corpus of rat epididymis and was abundant in the proximal corpus of mouse epididymis. GCNF could be found in the nuclei of the principal, apical, narrow, clear and halo cells. Conclusion: GCNF may play an important role in epididymal differentiation and development and in sperm maturation.
基金This study was supported by the National Essential Foundation Study Progress Plan“973”of China under contract No.G 1999043700.
文摘Quantitative distribution of planktonic amphipoda in the East China Sea is analyzed and the relation with environmental factors and mackerel and scad fishing grounds is studied. The result shows that the characteristic of biomass is great seasonal and interannual variety during the passing three decades. The distribution of planktonic amphipoda basically reflects the movement, decay and intensification of the different water systems in the survey area.
