The‘15-minute city’(15minC)concept,which aspires to bring essential services within reach via a 15-minute walk for all residents,represents a pivotal paradigm shift in sustainable urban development.However,the achie...The‘15-minute city’(15minC)concept,which aspires to bring essential services within reach via a 15-minute walk for all residents,represents a pivotal paradigm shift in sustainable urban development.However,the achievability of this concept for different cities varies considerably across diverse population distributions,urban contexts,and development priorities.In this study,we propose a robust method for evaluating a city’s 15minC potential-a city’s capability to achieve widespread 15-minute accessibility while maintaining an optimal balance between resource efficiency and resident accessibility.We employ the Location Set Covering Problem optimization model to analyze the resources required to achieve full coverage of 15-minute accessibility and the knee point detection algorithm to assess a city’s 15minC potential.Across 23 major Chinese cities,our method exhibits a sharp sensitivity to delineate distinct 15minC potentials.It reveals that cities’current 15minC development level doesn’t align with their inherent potential uniformly.Key determinants include how well current facility locations match population centers and the population density in remote areas.Further,reducing facility constructions by twothirds has only a marginal impact on accessibility,emphasizing the need for tailored,data-driven planning in effective and sustainable urban development based on the distinct potentials of cities.Our approach prioritizes resource efficiency,minimizing the inefficient use of facilities that serve only a small portion of residents while maximizing the benefits of the 15minC and therefore has significant implications for a sustainable urban future.展开更多
Based on the theory of all-for-one tourism,a multi-scale analysis method is adopted to systematically evaluate red tourism resources.At the micro level,red tourism resources are analyzed from five evaluation dimension...Based on the theory of all-for-one tourism,a multi-scale analysis method is adopted to systematically evaluate red tourism resources.At the micro level,red tourism resources are analyzed from five evaluation dimensions:attention,supporting degree,accessibility,relevance,and differentiation;at the macro level,taking districts and counties as the basic units,indicators such as the quantity of red tourism resources in districts and counties,the number of red tourism resources at or above the provincial level,road network density and coverage density of red tourism resources,the average value of individual indicators in five dimensions within districts and counties,economic level,population,and fiscal expenditure are selected.Using entropy weight method,the weight coefficients of each indicator are calculated,and then the development potential of red tourism resources in Nanchang City is scientifically evaluated.At the individual scale,the most important indicators that affect development potential are attention,relevance,and supporting degree.At the global scale,the most important indicators that affect development potential are attention,differentiation,and relevance.The red tourism resources in Nanchang City with the highest comprehensive score are Mao Zedong Thought Victory Museum,Bayi Square,Fang Zhimin Patriotic Theme Education Exhibition Hall,Fang Zhimin Martyrs Cemetery,and Bayi Uprising Memorial Hall.The counties and districts with the highest comprehensive score are Donghu District,Xihu District,and Qingshanhu District.Among the red tourism resources in Nanchang City,only a small portion have a high level of development potential,while the development potential of most individuals and counties is at a moderate level.Moreover,individuals and counties adjacent to the city center generally show more significant development advantages.展开更多
The developmental competence of porcine parthenotes cultured in porcine zygote medium-3 （PZM-3） and North Carolina State University-23 （NCSU-23） media was investigated. After in vitro maturation oocytes were elect...The developmental competence of porcine parthenotes cultured in porcine zygote medium-3 （PZM-3） and North Carolina State University-23 （NCSU-23） media was investigated. After in vitro maturation oocytes were electro-activated, and the subsequent developmental competence, rates of apoptotic, fragmented and arrested embryos from the two media were evaluated. Also, the ratio of mRNA expression of Bcl-2 and Bax gene was determined. Results demonstrated that cleavage, blastocyst, hatched blastocyst rates, and blastocyst cell numbers were significantly higher in PZM-3 than in NCSU-23. The rate of fragmented embryos in PZM-3 was lower than in NCSU-23 on d 1 and 3 （P〈0.05） while the percentage of arrested embryo was lower in PZM-3 than in NCSU-23 on d 4 and 5 （P〈0.05）. TUNEL positive signals were higher in NCSU-23 than in PZM-3 from d 3 to 7 （P〈0.05）. The ratios of Bcl-2 and Bax mRNA expression in embryos were higher on d 5 than on d 3 and 1 in PZM-3 （P〈0.05）. In contrast, the ratios of Bcl-2 and Bax mRNA expression in embryos on d 1 were higher than on d 3 and 5 in NCSU-23 （P〈0.05）. Additionally, the ratios of Bcl-2 and Bax mRNA expression in embryos in PZM-3 were higher than in NCSU-23 on d 3 and 5 （P〈0.05）. In conclusion, lower apoptotic embryo rates and down-regulating Bax together with up-regulating expression of Bcl-2 transcripts may be responsible for the better developmental competence of porcine parthenotes in PZM-3.展开更多
To investigate the relationship between the ATP content in human oocytes and the deve-lopmental potential of human oocytes, unfertilized oocytes from clinical IVF and immature oocytes unsuitable for ICSI were collecte...To investigate the relationship between the ATP content in human oocytes and the deve-lopmental potential of human oocytes, unfertilized oocytes from clinical IVF and immature oocytes unsuitable for ICSI were collected. The ATP content of these unfertilized and in vitro matured eggs were determined quantitatively by measuring the luminescence using an ATP-dependent bioluminescence assay. The result showed that the ATP content of unfertilized oocytes was higher than in vitro matured ones (2.20±0.67 pmol vs 1.72±0.49 pmol, P<0.05 ). In unfertilized oocytes, the ATP content of those whose fertilization rates (FR) was higher than 50 % was 2.43±0.60 pmol, which was significantly different from those whose FR was less than 50 % (1.72±0.56 pmol), while in in vitro matured oocytes, the ATP content of those whose FR more than 50 % was 1.8±0.44 pmol, slightly higher than those less than 50 % (1.55±0.40 pmol), without statistical significance. There was a tendency that the ATP content of oocytes of pregnant patients was higher than those of controls, but the sample number was too small to show any significance in statistics. Briefly, there was positive correlation between the ATP content in oocytes and developmental potential of oocytes.展开更多
Based on an investigation of the meaning of development, the neo-classical economic approach to development, and the post-welfarist theory of development, this paper proposes a conceptual framework for understanding h...Based on an investigation of the meaning of development, the neo-classical economic approach to development, and the post-welfarist theory of development, this paper proposes a conceptual framework for understanding human development potentials, while undertaking empirical analysis using cross-sectional and time series data on human development. Human development is associated with basic necessities for subsistence, the quality of life, and political and civil rights, in addition to income indicators. Our analysis suggests that the concept of human development potentials has two dimensions: the rights of development and limits to human development. Both are largely ignored in the neoclassical theory of development. However, human development is not unbounded, which approaches to a relatively fixed constant at given economic, technological and institutional conditions. This conceptual understanding is supported by results from the empirical examination of the relationships between demands for carbon展开更多
The containerized traffic has come into being for over forty years and has become the most important mode of sea transportation. Although containerized traffic trade has been developed in port cities of Dalian, Yingko...The containerized traffic has come into being for over forty years and has become the most important mode of sea transportation. Although containerized traffic trade has been developed in port cities of Dalian, Yingkou, Dandong and Jinzhou in Liaoning Province, yet their development sped are obviously slower than the entire national development pace. In the article, the authors make a systematic study on the current situation and the potential developmental possibility of containerized traffic in Liaoning Province. It is held that the relative low proportion of the supply of goods in hinterland is relative low which will restrict directly the development potentiality of the container harbors in Liaoning. Three countermeasures of the containerized traffic development were given accordingly.展开更多
Traditional music is an important component of cultural heritage.However,studies have scarcely explored the tourism development potential and the obstacle factors of traditional music.This study takes Xiangxi as the r...Traditional music is an important component of cultural heritage.However,studies have scarcely explored the tourism development potential and the obstacle factors of traditional music.This study takes Xiangxi as the research site,constructs an evaluation index system,and utilizes survey and geographical methods.The major research results are as follows:First,the average potential of resource endowment,tourism industry development,and socio-economic conditions are 0.28,0.36,and 0.24,respectively.The potential of resource endowment is higher in the west and lower in the east,that of tourism industry development is higher in the north and south and lower in the center,and that of socio-economic conditions is higher in the south and lower in the north.Second,the comprehensive potential is 0.29,which is higher in the northwest and southwest regions.Coordination in most administrative units is at a medium level,and most regions have obvious advantages in resource endowment.Third,the primary obstacle factor is socio-economic conditions(39.21%),followed by resource endowment(30.73%)and tourism industry development(30.06%).The administrative units can be classified into four groups:socio-economic condition obstacle,resource endowment and tourism industry development obstacles,resource endowment and socio-economic condition obstacles,and tourism industry development and socio-economic condition obstacles.The highest priority goals for Xiangxi involve economic development and the integration of modern technologies to stimulate passenger flow.For reg traditional music items(eastern area of Xiangxi),tourism development should be restrained and other resources with stronger inherent advantages should be exploited.This study explored the quantification of traditional music tourism potential,representing a novel breakthrough in this field of research.The indicator system and research methods used in this study can provide guidance and methodological references for cultural heritage research.The suggestions proposed in this article contribute to the rational development and effective protection of cultural heritage resources and the healthy development of the tourism industry.展开更多
Hainan Island is located in the northwestern South China Sea at the boundary of two tectonic plates.Surface features and actual drilling have confirmed that there are rich geothermal resources in the area,with predict...Hainan Island is located in the northwestern South China Sea at the boundary of two tectonic plates.Surface features and actual drilling have confirmed that there are rich geothermal resources in the area,with predicted resources of 480 million GWh.On the basis of the 1:200,000 gravity and 1:10 aeromagnetic data and constrained by the well-explored Fushan Depression and Baocheng Rock Mass,we conducted a sys-tematic study of hot dry rocks and evaluated the development potential of the geothermal resources of the medium-depth and deep hot dry rocks in Hainan Island for thefirst time.The island is structurally active,with extensive granites,strong volcanic and earthquake activities,and many hot springs,indicating that the geothermal geological conditions are favorable.There are two types of hot dry rocks,sedimentary basin type and uplifted mountain type,on the island.The sedimentary basin-type hot dry rocks are mainly found in the north of the island and have an area of 2657 km^(2),an average depth of 2480 m,and an average heat reservoir temperature of 230℃ at 6000 m depth.Uplifted mountain-type hot dry rocks with a total area of 13,000 km^(2) mainly occur in Danzhou in the north of the island and Baocheng in the south.The heat reservoirs of these rocks are Yanshanian intrusive plutons and the average temperature is 236℃ at 6000 m depth.Nine favorable hot dry rock targets are identified,of whichfive are sedimentary basin types and four are uplifted mountain types.The Fushan and Eman depressions in north Hainan Island and the Baocheng Rock Mass in the south of the island are the preferred exploration targets.展开更多
This paper presents an analysis of four aspects,including the distribution and production of global oil and gas fields,the distribution and changes of remaining recoverable reserves,the differences in oil and gas prod...This paper presents an analysis of four aspects,including the distribution and production of global oil and gas fields,the distribution and changes of remaining recoverable reserves,the differences in oil and gas production between regions/countries,and the development potentials of oil and gas fields unproduced and to be produced in 2023.On this basis,the situation and characteristics of global oil and gas development are expounded,and the trend of global oil and gas development is summarized.In 2023,upstream oil and gas production landscape is expanding,and the number of oil and gas fields in production is increasing significantly;oil and gas recoverable reserves increased year-on-year,driven by significant contributions from new discoveries and reserve re-estimates;the overall oil and gas production grew continuously,with notable contributions from new projects coming online and capacity expansion efforts;and the oil and gas fields unproduced or to be produced,especially large onshore conventional oil fields and economically challenging offshore gas fields,host abundant recoverable reserves.From the perspectives of reshaping oil and gas production areas due to the pandemic and Russia-Ukraine conflicts,geopolitical crises,capital expenditure structures in petroleum exploration and development,and the proactive layout of oil and gas associated resources,the trend of global oil and gas development in 2023 was analyzed systematically.The enlightenment and suggestions in four aspects are proposed for Chinese oil companies to focus on core businesses and clarify development strategies in the post-pandemic era and the context of energy transition:The global oil and gas landscape is undergoing profound adjustments,and it is essential to grasp development trends,especially in core businesses;upstream business exhibits a strong potential,and emerging fields are considered as new growth poles;the prospects for tight/shale oil and gas are promising,and new pathways to ensure national energy security are explored;cutting-edge breakthroughs are achieved in emerging industries of strategic importance,and a comprehensive energy collaboration system for supply security is established.展开更多
Western Guizhou is a favorable region for coalbed methane(CBM)exploration and development in Guizhou Province.Affected by complex geological conditions,the heterogeneity of middle-high rank coal reservoirs is strong,a...Western Guizhou is a favorable region for coalbed methane(CBM)exploration and development in Guizhou Province.Affected by complex geological conditions,the heterogeneity of middle-high rank coal reservoirs is strong,and the geological and engineering control effects on enrichment and high productivity of CBM are significantly different.This paper comparatively analyzes the characteristics of middle-and high-rank coal reservoirs in the western Guizhou region,revealing the productivity characteristics and gas/water production rules of typical middle-high rank CBM high-yield wells.Moreover,it establishes a geological-engineering control model for the enrichment and high productivity of CBM in middle-high-rank coal seams in the western Guizhou region and analyzes the exploration and development potential and direction of middle-high-rank CBM in the region.The results are as follows.First,the middle-rank coal in the western Guizhou region is represented by the Liupanshui coalfield,where cleats and fractures are well developed,the content of macropores and mesopores is relatively high,the permeability is good,and the adsorption capacity is relatively weak.The high-rank coal is represented by the Zhina coalfield,where micropores are well developed,the permeability is greatly affected by burial depth,and the adsorption capacity is strong.Second,the difference in the characteristics of middle-rank and high-rank coal reservoirs in the western Guizhou region is mainly reflected in the pore-permeability conditions and adsorption capacity.The porosity and permeability of middle-rank coal samples are both greater than those of high-rank coal samples,and the development of secondary microfractures is the main reason for the relatively high permeability of middle-rank coal,while the well-developed micropores in high-rank coal provide more space for CBM preservation.Third,the CBM highyield wells in middle-rank coal seams in the western Guizhou region have the characteristics of“relatively high water production and high gas production,”while those of high-rank coal seams have the characteristics of“low water production and high gas production”or“high water production and low gas production.”The gas content and permeability of the coal reservoirs are the common constraints on whether CBM in middle-high rank coal seams can be highly productive under complex geological conditions.Fourth,the enrichment and high productivity of CBM in middle-high rank coal seams under complex geological conditions is the result of the synergistic matching of depth structure hydrology and adaptive fracturing production techniques.The CBM enrichment model,reservoir reformability,and gas/water production characteristics under geological and engineering synergistic control are unique and complex.Fifth,the middle-high rank coal seams in the western Guizhou region exhibit the basic resource characteristics of high gas content and high CBM resource abundance.Carrying out a precise evaluation of the CBM dual sweet spot system and reservoir volume stimulation are important guarantees for the efficient exploration and development of CBM in the western Guizhou region.展开更多
[Objective] The aim was to make analysis on natural condition,present situation,and potential of rice production development in Angola.[Method] Conclusion and analysis of rice development in Angola were conducted from...[Objective] The aim was to make analysis on natural condition,present situation,and potential of rice production development in Angola.[Method] Conclusion and analysis of rice development in Angola were conducted from natural condition,production status,present problem and development potential.[Result] In Angola,about 30 million hectares agricultural lands enjoy fresh water,temperature,and light resources which are requirement for rice development.Presently,however,some disadvantages have harassed the nation,such as outdated production mode and technology,small cultivated area and low level of per unit yield.In addition,about 98% of consumed rice was imported from other countries.The government has attached high importance to food production,and rice production was a priority of national investment.Per unit rice yield would achieve 7 500 kg/hm2 if Angola introduces hybrid rice species and high-yield cultivation techniques from China.[Conclusion] The research provided technical reference for enterprises or individuals ready to invest in rice development in Angola.展开更多
Based on the characteristics of agricultural resources and social resources in Shandong Province, the approaches of developing farming system potential were discussed, which provide important references for sustainabl...Based on the characteristics of agricultural resources and social resources in Shandong Province, the approaches of developing farming system potential were discussed, which provide important references for sustainable development of modern farming system.展开更多
The research reviewed biological characters and nutritional value of Chenopodium quinoa and concluded status quo of domestic cultivation and problems at promotion, as wel as application prospect in order to provide re...The research reviewed biological characters and nutritional value of Chenopodium quinoa and concluded status quo of domestic cultivation and problems at promotion, as wel as application prospect in order to provide references for re-search and development of Chenopodium quinoa.展开更多
By analyzing the distribution of global oil and gas fields and the reasons why some oil and gas fields are not in production, the distribution characteristics of oil and gas remaining recoverable reserves and their ye...By analyzing the distribution of global oil and gas fields and the reasons why some oil and gas fields are not in production, the distribution characteristics of oil and gas remaining recoverable reserves and their year-on-year changes, the distribution characteristics of oil and gas production and their year-on-year changes, and the development potential of oil and gas to be tapped in 2021, this paper sorts out systematically the current status and characteristics of global oil and gas development, summaries the major trends of global oil and gas development, puts forward enlightenment for international oil and gas cooperation. In 2021, oil and gas fields were widely distributed, the number of non-producing oil and gas fields was large;the whole oil and gas remaining recoverable reserves declined slightly, unconventional oil and gas remaining recoverable reserves dropped significantly;the overall oil and gas production continuously increased, the outputs of key resource-host countries kept year-on-year growth;undeveloped oilfields had abundant reserves and great development potential. Combined with global oil and gas geopolitics, oil and gas industry development trends, oil and gas investment intensity, and the tracking and judgment of hotspot fields, the major trends of global oil and gas development in 2021 are summarized. On this basis, the four aspects of enlightenment and suggestions for international oil and gas cooperation and development strategies are put forward: attach great importance to the obligation of marine abandonment to ensure high-quality and long-term benefit development of offshore oil and gas;adhere to the principle of not going to dangerous and chaotic places, strengthen the concentration of oil and gas assets, and establish multi stable supply bases;based on the multi-scenario demand of natural gas, realize the transformation from integrated collaboration to full oil and gas industry chain development;increase the acquisition of high-quality large-scale assets, and pay attention to the continuous optimization of the shareholding ratio of projects at different stages.展开更多
With the increasing severity of environmental problems,many countries have set energy transition targets to promote the realization of the Paris Agreement.There has been a global consensus on utilizing solar energy re...With the increasing severity of environmental problems,many countries have set energy transition targets to promote the realization of the Paris Agreement.There has been a global consensus on utilizing solar energy resources as alternatives to conventional sources to support this energy transition.In this regard,analyzing the“location,”“quantity,”and“quality”of global solar energy resources will not only assist an individual country to efficiently utilize these resources but also promote the realization of large-scale intercontinental resource utilization and complementation.This study established the basic database,model methods,and platform tools for global solar energy assessment,Then,a global solar energy resource assessment was conducted,which included the theoretical reserves(TRs),technical installed potential capacity(TPIC),and average development cost(ADC).A comparative analysis of the assessment results for all continents was also performed.After that,based on big data analysis and geographic information system(GIS)calculations,the distribution characteristics of the global solar power TPIC were calculated with the two core indicators,namely the capacity factor and ADC.Furthermore,a data-driven quantitative evaluation of the refined development potential of solar energy resources was performed.Finally,the reasonableness and coincidence analysis of the resource assessment results were verified using data from global and specifically Chinese photovoltaic(PV)bases.展开更多
Through analysis of four aspects,including the distribution and production of global oil and gas fields,the distribution and changes of remaining recoverable reserves,the differences in oil and gas production between ...Through analysis of four aspects,including the distribution and production of global oil and gas fields,the distribution and changes of remaining recoverable reserves,the differences in oil and gas production between regions/countries,and the development potential of oil and gas fields with production capacity not built and to be built,this paper presents the situation and trends of global oil and gas development in 2022.It is found that,in 2022,oil and gas fields are widely distributed worldwide,and upstream production activities continue to recover;the oil and gas reserves decrease slightly year on year,and the oil and gas reserves in sea areas increase significantly;the oil and gas production increases continuously,and the key resource countries make a significant contribution in oil and gas production growth;the oil and gas fields with production capacity not built and to be built hold abundant reserves,and their development potential will be gradually released with the economic benefits increase.Further analysis is conducted from the perspectives of global oil and gas resources continuity,geopolitical risks,potential of international cooperation,and upgrade of unconventional oil and gas technology.Finally,in view of core business domains and strategies under the new situation,the Chinese oil companies are recommended to:(1)keep a foothold in onshore conventional oil and gas development by virtue of their comparative advantages and learning from other’s experience in cooperation;(2)carry out pilot tests on development adjustment,and deepen the international cooperation in enhanced oil/gas recovery;(3)improve the oil and gas operation capabilities in sea areas to transform from follower as minority shareholder to joint venture and then to independent operations;and(4)seek appropriate ways for shale oil/gas development to reduce the dependence on foreign oil and gas.展开更多
With the advent of the era of big data and artificial intelligence, new infrastructure construction(NIC) has attracted the attention of many countries. The development of NIC provides an opportunity to bridge the digi...With the advent of the era of big data and artificial intelligence, new infrastructure construction(NIC) has attracted the attention of many countries. The development of NIC provides an opportunity to bridge the digital divide and narrow the regional gap,providing continuous impetus to further promote economic development. Here, we considered 31 provincial-level administrative units in China(not including Hong Kong, Macao, and Taiwan of China due to data unavailable) and established comprehensive evaluation indicators for the development potential of NIC. Afterward, we used the entropy-weight TOPSIS model to determine the development potential of NIC and analyze its spatio-temporal evolution characteristics. Furthermore, the GeoDetector model was applied to explore the driving mechanism of the NIC development potential. The conclusions were as follows: (1) The Chinese NIC development potential is generally low. The eastern China was the region with the highest development potential year by year, while the development potential in the central China was found to be in an accelerating phase. (2) The evolution of the Chinese NIC development potential’s spatial pattern has been characterized by an inland extension and coastal agglomeration. Moreover, we identified a superior development zone, a rising development zone, an inferior development zone, and a declining development zone. (3) The scope of Chinese NIC development potential agglomeration areas has gradually expanded and its degree has gradually deepened. The range of high-value agglomeration in eastern area gradually expanded and its degree gradually deepened. (4) Investment in innovative talents appears as the core factor affecting the Chinese NIC development potential. Whether acting alone or synergistically with other factors, its promoting effect on Chinese NIC development potential is the strongest.展开更多
At present,natural gas accounts for a low proportion in China's primary energy consumption structure and is highly dependent on foreign sources.Changqing gas province of the Ordos Basin where PetroChina Changqing ...At present,natural gas accounts for a low proportion in China's primary energy consumption structure and is highly dependent on foreign sources.Changqing gas province of the Ordos Basin where PetroChina Changqing Oilfield Company(referred to as Changqing Oilfield)is located is one of China's four major natural gas production bases.It bears the important responsibility for ensuring people's livelihood and promoting the healthy development of society economy.In recent years,Changqing Oilfield actively implements national instructive spirit on vigorously promoting domestic oil and gas exploration and development strength and formulates the secondary acceleration development strategies.Its annual natural gas production in 2020 reaches 448.5×10^(8) m^(3) and oil and gas equivalent exceeds 6000×10^(4) t,tamping its important position of“Western Daqing”in this industry.In order to further promote the continuous stable production and realize the goal of quality and efficiency improvement in Changqing gas province,this paper analyzes the situations and challenges of natural gas development in this gas province,prepares the development technological countermeasures and forecast the natural gas development prospect.And the following research results are obtained.First,the natural gas exploration and development in Changqing gas province is divided into four stages and the main technologies for the development of low-permeability carbonate gas reservoir,low-permeability sandstone gas reservoir and tight sandstone gas reservoir are formed.Second,the natural gas development in Changqing gas province faces six challenges,such as low reserve production degree,sharp decline of production rates and complex distribution of remaining undeveloped reserves of developed gas fields.And twenty-six development technological countermeasures are put forward correspondingly,such as well pattern thickening,extension and reserve increase,secondary production layer potential tapping and fine gas well management.Third,the development direction and goal of natural gas development in Changqing gas province is to pay equal attention to the stable production of old gas fields and the production increase of new areas and carry out conventional gas and unconventional gas research simultaneously.In conclusion,the annual natural gas production of Changqing gas province will maintain a sound momentum of steady growth and will exceed 500×10^(8) m^(3) at the end of the 14th Five-Year Plan and maintain at a stable level for a long term,which is conducive to the optimization of domestic energy consumption structure and realization of“carbon peak and carbon neutrality”.展开更多
Microorganisms, regardless of whether pathogenic or not, may cause enormous economic losses due to adverse effects on human and animal health, or by damaging the quality of the agricultural and food products. Based on...Microorganisms, regardless of whether pathogenic or not, may cause enormous economic losses due to adverse effects on human and animal health, or by damaging the quality of the agricultural and food products. Based on these effects, the development of prompt molecular methods and their involvement in the practical pathogen diagnostic diagnostics is more than actual. This paper is focused on the evaluation of easy-to-perform and highly budget-friendly, PCR-related DNA purification protocols for diagnostic purposes especially in water or similar simple matrices. The slight modifications of earlier described DNA isolation methods, which rely on chelate exchange resin and/or ethanol-sodium-based heat lysis, we reevaluated in comparison with a widely used commercial kit. The efficiency of DNA purification techniques was assessed from Gramnegative as well as Gram-positive bacteria and yeast using quantitative PCR. The effectivity of different methods tested may vary depending on the bacterial or yeast species in question. Nevertheless, in our hands, the chelate exchange resin-based methods were found to be the most robust and/or satisfying at least by an acceptable reproducibility rate. Our presented results support the potential of low-cost but still sensitive molecular microbe detection procedures consisting of only a few pipetting steps resulting in good reproducibility and the least possible environmental burden, serving as a good starting point for developments of matrix-specific processes and methods.展开更多
基金supported by grants from the Hong Kong Research Grants Council(General Research Fund Grants No.14605920,14611621,14606922,14603724Collaborative Research Fund Grant No.C4023-20GF+2 种基金Research Matching Grants No.8601219,8601242,3110156)a grant from the Research Committee on Research Sustainability of Major Research Grants Council Funding Schemes(Grant No.3133235)of the Chinese University of Hong Kongfunding from the Improvement on Competitiveness in Hiring New Faculties Funding Scheme of The Chinese University of Hong Kong.
文摘The‘15-minute city’(15minC)concept,which aspires to bring essential services within reach via a 15-minute walk for all residents,represents a pivotal paradigm shift in sustainable urban development.However,the achievability of this concept for different cities varies considerably across diverse population distributions,urban contexts,and development priorities.In this study,we propose a robust method for evaluating a city’s 15minC potential-a city’s capability to achieve widespread 15-minute accessibility while maintaining an optimal balance between resource efficiency and resident accessibility.We employ the Location Set Covering Problem optimization model to analyze the resources required to achieve full coverage of 15-minute accessibility and the knee point detection algorithm to assess a city’s 15minC potential.Across 23 major Chinese cities,our method exhibits a sharp sensitivity to delineate distinct 15minC potentials.It reveals that cities’current 15minC development level doesn’t align with their inherent potential uniformly.Key determinants include how well current facility locations match population centers and the population density in remote areas.Further,reducing facility constructions by twothirds has only a marginal impact on accessibility,emphasizing the need for tailored,data-driven planning in effective and sustainable urban development based on the distinct potentials of cities.Our approach prioritizes resource efficiency,minimizing the inefficient use of facilities that serve only a small portion of residents while maximizing the benefits of the 15minC and therefore has significant implications for a sustainable urban future.
基金Sponsored by the Humanities and Social Sciences Research Project in Jiangxi Province’s Universities(YS23104).
文摘Based on the theory of all-for-one tourism,a multi-scale analysis method is adopted to systematically evaluate red tourism resources.At the micro level,red tourism resources are analyzed from five evaluation dimensions:attention,supporting degree,accessibility,relevance,and differentiation;at the macro level,taking districts and counties as the basic units,indicators such as the quantity of red tourism resources in districts and counties,the number of red tourism resources at or above the provincial level,road network density and coverage density of red tourism resources,the average value of individual indicators in five dimensions within districts and counties,economic level,population,and fiscal expenditure are selected.Using entropy weight method,the weight coefficients of each indicator are calculated,and then the development potential of red tourism resources in Nanchang City is scientifically evaluated.At the individual scale,the most important indicators that affect development potential are attention,relevance,and supporting degree.At the global scale,the most important indicators that affect development potential are attention,differentiation,and relevance.The red tourism resources in Nanchang City with the highest comprehensive score are Mao Zedong Thought Victory Museum,Bayi Square,Fang Zhimin Patriotic Theme Education Exhibition Hall,Fang Zhimin Martyrs Cemetery,and Bayi Uprising Memorial Hall.The counties and districts with the highest comprehensive score are Donghu District,Xihu District,and Qingshanhu District.Among the red tourism resources in Nanchang City,only a small portion have a high level of development potential,while the development potential of most individuals and counties is at a moderate level.Moreover,individuals and counties adjacent to the city center generally show more significant development advantages.
基金funded by the National Natural Science Foundation of China (31072031)the Key Research Program of Ministry of Education of China(109018)
文摘The developmental competence of porcine parthenotes cultured in porcine zygote medium-3 （PZM-3） and North Carolina State University-23 （NCSU-23） media was investigated. After in vitro maturation oocytes were electro-activated, and the subsequent developmental competence, rates of apoptotic, fragmented and arrested embryos from the two media were evaluated. Also, the ratio of mRNA expression of Bcl-2 and Bax gene was determined. Results demonstrated that cleavage, blastocyst, hatched blastocyst rates, and blastocyst cell numbers were significantly higher in PZM-3 than in NCSU-23. The rate of fragmented embryos in PZM-3 was lower than in NCSU-23 on d 1 and 3 （P〈0.05） while the percentage of arrested embryo was lower in PZM-3 than in NCSU-23 on d 4 and 5 （P〈0.05）. TUNEL positive signals were higher in NCSU-23 than in PZM-3 from d 3 to 7 （P〈0.05）. The ratios of Bcl-2 and Bax mRNA expression in embryos were higher on d 5 than on d 3 and 1 in PZM-3 （P〈0.05）. In contrast, the ratios of Bcl-2 and Bax mRNA expression in embryos on d 1 were higher than on d 3 and 5 in NCSU-23 （P〈0.05）. Additionally, the ratios of Bcl-2 and Bax mRNA expression in embryos in PZM-3 were higher than in NCSU-23 on d 3 and 5 （P〈0.05）. In conclusion, lower apoptotic embryo rates and down-regulating Bax together with up-regulating expression of Bcl-2 transcripts may be responsible for the better developmental competence of porcine parthenotes in PZM-3.
文摘To investigate the relationship between the ATP content in human oocytes and the deve-lopmental potential of human oocytes, unfertilized oocytes from clinical IVF and immature oocytes unsuitable for ICSI were collected. The ATP content of these unfertilized and in vitro matured eggs were determined quantitatively by measuring the luminescence using an ATP-dependent bioluminescence assay. The result showed that the ATP content of unfertilized oocytes was higher than in vitro matured ones (2.20±0.67 pmol vs 1.72±0.49 pmol, P<0.05 ). In unfertilized oocytes, the ATP content of those whose fertilization rates (FR) was higher than 50 % was 2.43±0.60 pmol, which was significantly different from those whose FR was less than 50 % (1.72±0.56 pmol), while in in vitro matured oocytes, the ATP content of those whose FR more than 50 % was 1.8±0.44 pmol, slightly higher than those less than 50 % (1.55±0.40 pmol), without statistical significance. There was a tendency that the ATP content of oocytes of pregnant patients was higher than those of controls, but the sample number was too small to show any significance in statistics. Briefly, there was positive correlation between the ATP content in oocytes and developmental potential of oocytes.
文摘Based on an investigation of the meaning of development, the neo-classical economic approach to development, and the post-welfarist theory of development, this paper proposes a conceptual framework for understanding human development potentials, while undertaking empirical analysis using cross-sectional and time series data on human development. Human development is associated with basic necessities for subsistence, the quality of life, and political and civil rights, in addition to income indicators. Our analysis suggests that the concept of human development potentials has two dimensions: the rights of development and limits to human development. Both are largely ignored in the neoclassical theory of development. However, human development is not unbounded, which approaches to a relatively fixed constant at given economic, technological and institutional conditions. This conceptual understanding is supported by results from the empirical examination of the relationships between demands for carbon
文摘The containerized traffic has come into being for over forty years and has become the most important mode of sea transportation. Although containerized traffic trade has been developed in port cities of Dalian, Yingkou, Dandong and Jinzhou in Liaoning Province, yet their development sped are obviously slower than the entire national development pace. In the article, the authors make a systematic study on the current situation and the potential developmental possibility of containerized traffic in Liaoning Province. It is held that the relative low proportion of the supply of goods in hinterland is relative low which will restrict directly the development potentiality of the container harbors in Liaoning. Three countermeasures of the containerized traffic development were given accordingly.
基金Project of Hunan Provincial Social Science Achievement Evaluation Committee,No.XSP2023GLC023Excellent Youth Program of the Education Department of Hunan Province,No.22B0692+2 种基金National Natural Science Fundation of China,No.41971191,No.42171213Project of Hunan University of Arts and Science,No.22BSQD15Project of Henan Philosophy and Social Sciences,No.2022BJJ026。
文摘Traditional music is an important component of cultural heritage.However,studies have scarcely explored the tourism development potential and the obstacle factors of traditional music.This study takes Xiangxi as the research site,constructs an evaluation index system,and utilizes survey and geographical methods.The major research results are as follows:First,the average potential of resource endowment,tourism industry development,and socio-economic conditions are 0.28,0.36,and 0.24,respectively.The potential of resource endowment is higher in the west and lower in the east,that of tourism industry development is higher in the north and south and lower in the center,and that of socio-economic conditions is higher in the south and lower in the north.Second,the comprehensive potential is 0.29,which is higher in the northwest and southwest regions.Coordination in most administrative units is at a medium level,and most regions have obvious advantages in resource endowment.Third,the primary obstacle factor is socio-economic conditions(39.21%),followed by resource endowment(30.73%)and tourism industry development(30.06%).The administrative units can be classified into four groups:socio-economic condition obstacle,resource endowment and tourism industry development obstacles,resource endowment and socio-economic condition obstacles,and tourism industry development and socio-economic condition obstacles.The highest priority goals for Xiangxi involve economic development and the integration of modern technologies to stimulate passenger flow.For reg traditional music items(eastern area of Xiangxi),tourism development should be restrained and other resources with stronger inherent advantages should be exploited.This study explored the quantification of traditional music tourism potential,representing a novel breakthrough in this field of research.The indicator system and research methods used in this study can provide guidance and methodological references for cultural heritage research.The suggestions proposed in this article contribute to the rational development and effective protection of cultural heritage resources and the healthy development of the tourism industry.
基金Research on Exploration and Evaluation of hot dry rock Resources and Target Area Preference(No.2023-HNKT-001)This article is sponsored by the New Energy Technology Development and Application Research Project No.2022DJ5503.
文摘Hainan Island is located in the northwestern South China Sea at the boundary of two tectonic plates.Surface features and actual drilling have confirmed that there are rich geothermal resources in the area,with predicted resources of 480 million GWh.On the basis of the 1:200,000 gravity and 1:10 aeromagnetic data and constrained by the well-explored Fushan Depression and Baocheng Rock Mass,we conducted a sys-tematic study of hot dry rocks and evaluated the development potential of the geothermal resources of the medium-depth and deep hot dry rocks in Hainan Island for thefirst time.The island is structurally active,with extensive granites,strong volcanic and earthquake activities,and many hot springs,indicating that the geothermal geological conditions are favorable.There are two types of hot dry rocks,sedimentary basin type and uplifted mountain type,on the island.The sedimentary basin-type hot dry rocks are mainly found in the north of the island and have an area of 2657 km^(2),an average depth of 2480 m,and an average heat reservoir temperature of 230℃ at 6000 m depth.Uplifted mountain-type hot dry rocks with a total area of 13,000 km^(2) mainly occur in Danzhou in the north of the island and Baocheng in the south.The heat reservoirs of these rocks are Yanshanian intrusive plutons and the average temperature is 236℃ at 6000 m depth.Nine favorable hot dry rock targets are identified,of whichfive are sedimentary basin types and four are uplifted mountain types.The Fushan and Eman depressions in north Hainan Island and the Baocheng Rock Mass in the south of the island are the preferred exploration targets.
基金Supported by the Petro China Scientific Research and Technology Development Project(2023SC0105)。
文摘This paper presents an analysis of four aspects,including the distribution and production of global oil and gas fields,the distribution and changes of remaining recoverable reserves,the differences in oil and gas production between regions/countries,and the development potentials of oil and gas fields unproduced and to be produced in 2023.On this basis,the situation and characteristics of global oil and gas development are expounded,and the trend of global oil and gas development is summarized.In 2023,upstream oil and gas production landscape is expanding,and the number of oil and gas fields in production is increasing significantly;oil and gas recoverable reserves increased year-on-year,driven by significant contributions from new discoveries and reserve re-estimates;the overall oil and gas production grew continuously,with notable contributions from new projects coming online and capacity expansion efforts;and the oil and gas fields unproduced or to be produced,especially large onshore conventional oil fields and economically challenging offshore gas fields,host abundant recoverable reserves.From the perspectives of reshaping oil and gas production areas due to the pandemic and Russia-Ukraine conflicts,geopolitical crises,capital expenditure structures in petroleum exploration and development,and the proactive layout of oil and gas associated resources,the trend of global oil and gas development in 2023 was analyzed systematically.The enlightenment and suggestions in four aspects are proposed for Chinese oil companies to focus on core businesses and clarify development strategies in the post-pandemic era and the context of energy transition:The global oil and gas landscape is undergoing profound adjustments,and it is essential to grasp development trends,especially in core businesses;upstream business exhibits a strong potential,and emerging fields are considered as new growth poles;the prospects for tight/shale oil and gas are promising,and new pathways to ensure national energy security are explored;cutting-edge breakthroughs are achieved in emerging industries of strategic importance,and a comprehensive energy collaboration system for supply security is established.
基金supported by the“Belt and Road”Innovation Cooperation Project of Jiangsu Province(Grant No.BZ2022015)the National Natural Science Foundation of China(No.42030810 and 42102207)Geological Exploration Foundation of Guizhou Province(No.52000021MGQSE7S7K6PRP).
文摘Western Guizhou is a favorable region for coalbed methane(CBM)exploration and development in Guizhou Province.Affected by complex geological conditions,the heterogeneity of middle-high rank coal reservoirs is strong,and the geological and engineering control effects on enrichment and high productivity of CBM are significantly different.This paper comparatively analyzes the characteristics of middle-and high-rank coal reservoirs in the western Guizhou region,revealing the productivity characteristics and gas/water production rules of typical middle-high rank CBM high-yield wells.Moreover,it establishes a geological-engineering control model for the enrichment and high productivity of CBM in middle-high-rank coal seams in the western Guizhou region and analyzes the exploration and development potential and direction of middle-high-rank CBM in the region.The results are as follows.First,the middle-rank coal in the western Guizhou region is represented by the Liupanshui coalfield,where cleats and fractures are well developed,the content of macropores and mesopores is relatively high,the permeability is good,and the adsorption capacity is relatively weak.The high-rank coal is represented by the Zhina coalfield,where micropores are well developed,the permeability is greatly affected by burial depth,and the adsorption capacity is strong.Second,the difference in the characteristics of middle-rank and high-rank coal reservoirs in the western Guizhou region is mainly reflected in the pore-permeability conditions and adsorption capacity.The porosity and permeability of middle-rank coal samples are both greater than those of high-rank coal samples,and the development of secondary microfractures is the main reason for the relatively high permeability of middle-rank coal,while the well-developed micropores in high-rank coal provide more space for CBM preservation.Third,the CBM highyield wells in middle-rank coal seams in the western Guizhou region have the characteristics of“relatively high water production and high gas production,”while those of high-rank coal seams have the characteristics of“low water production and high gas production”or“high water production and low gas production.”The gas content and permeability of the coal reservoirs are the common constraints on whether CBM in middle-high rank coal seams can be highly productive under complex geological conditions.Fourth,the enrichment and high productivity of CBM in middle-high rank coal seams under complex geological conditions is the result of the synergistic matching of depth structure hydrology and adaptive fracturing production techniques.The CBM enrichment model,reservoir reformability,and gas/water production characteristics under geological and engineering synergistic control are unique and complex.Fifth,the middle-high rank coal seams in the western Guizhou region exhibit the basic resource characteristics of high gas content and high CBM resource abundance.Carrying out a precise evaluation of the CBM dual sweet spot system and reservoir volume stimulation are important guarantees for the efficient exploration and development of CBM in the western Guizhou region.
基金Supportd by Science and Technology Cooperation Project of Anhui Science and Technology Department (11030603031)~~
文摘[Objective] The aim was to make analysis on natural condition,present situation,and potential of rice production development in Angola.[Method] Conclusion and analysis of rice development in Angola were conducted from natural condition,production status,present problem and development potential.[Result] In Angola,about 30 million hectares agricultural lands enjoy fresh water,temperature,and light resources which are requirement for rice development.Presently,however,some disadvantages have harassed the nation,such as outdated production mode and technology,small cultivated area and low level of per unit yield.In addition,about 98% of consumed rice was imported from other countries.The government has attached high importance to food production,and rice production was a priority of national investment.Per unit rice yield would achieve 7 500 kg/hm2 if Angola introduces hybrid rice species and high-yield cultivation techniques from China.[Conclusion] The research provided technical reference for enterprises or individuals ready to invest in rice development in Angola.
基金Supported by the Scientific Research Project of Public Welfare Industry(Agriculture)(201103001)the Domestic Visiting Scholar Program for Excellent Young Teachers of Shandong Province 2009~~
文摘Based on the characteristics of agricultural resources and social resources in Shandong Province, the approaches of developing farming system potential were discussed, which provide important references for sustainable development of modern farming system.
基金Supported by Coarse Cereal Innovation Team of Shandong Province Modern Agricultural Technology SystemYouth Foundation of Shandong Academy of Agricultural Sciences(2014QNM09)~~
文摘The research reviewed biological characters and nutritional value of Chenopodium quinoa and concluded status quo of domestic cultivation and problems at promotion, as wel as application prospect in order to provide references for re-search and development of Chenopodium quinoa.
基金Scientific Research and Technology Development Project(2021DJ3205)。
文摘By analyzing the distribution of global oil and gas fields and the reasons why some oil and gas fields are not in production, the distribution characteristics of oil and gas remaining recoverable reserves and their year-on-year changes, the distribution characteristics of oil and gas production and their year-on-year changes, and the development potential of oil and gas to be tapped in 2021, this paper sorts out systematically the current status and characteristics of global oil and gas development, summaries the major trends of global oil and gas development, puts forward enlightenment for international oil and gas cooperation. In 2021, oil and gas fields were widely distributed, the number of non-producing oil and gas fields was large;the whole oil and gas remaining recoverable reserves declined slightly, unconventional oil and gas remaining recoverable reserves dropped significantly;the overall oil and gas production continuously increased, the outputs of key resource-host countries kept year-on-year growth;undeveloped oilfields had abundant reserves and great development potential. Combined with global oil and gas geopolitics, oil and gas industry development trends, oil and gas investment intensity, and the tracking and judgment of hotspot fields, the major trends of global oil and gas development in 2021 are summarized. On this basis, the four aspects of enlightenment and suggestions for international oil and gas cooperation and development strategies are put forward: attach great importance to the obligation of marine abandonment to ensure high-quality and long-term benefit development of offshore oil and gas;adhere to the principle of not going to dangerous and chaotic places, strengthen the concentration of oil and gas assets, and establish multi stable supply bases;based on the multi-scenario demand of natural gas, realize the transformation from integrated collaboration to full oil and gas industry chain development;increase the acquisition of high-quality large-scale assets, and pay attention to the continuous optimization of the shareholding ratio of projects at different stages.
基金supported by National Science and Technology Major Project(2018YFB0904000).
文摘With the increasing severity of environmental problems,many countries have set energy transition targets to promote the realization of the Paris Agreement.There has been a global consensus on utilizing solar energy resources as alternatives to conventional sources to support this energy transition.In this regard,analyzing the“location,”“quantity,”and“quality”of global solar energy resources will not only assist an individual country to efficiently utilize these resources but also promote the realization of large-scale intercontinental resource utilization and complementation.This study established the basic database,model methods,and platform tools for global solar energy assessment,Then,a global solar energy resource assessment was conducted,which included the theoretical reserves(TRs),technical installed potential capacity(TPIC),and average development cost(ADC).A comparative analysis of the assessment results for all continents was also performed.After that,based on big data analysis and geographic information system(GIS)calculations,the distribution characteristics of the global solar power TPIC were calculated with the two core indicators,namely the capacity factor and ADC.Furthermore,a data-driven quantitative evaluation of the refined development potential of solar energy resources was performed.Finally,the reasonableness and coincidence analysis of the resource assessment results were verified using data from global and specifically Chinese photovoltaic(PV)bases.
基金Supported by the PetroChina Science and Technology Project(2021DJ3205).
文摘Through analysis of four aspects,including the distribution and production of global oil and gas fields,the distribution and changes of remaining recoverable reserves,the differences in oil and gas production between regions/countries,and the development potential of oil and gas fields with production capacity not built and to be built,this paper presents the situation and trends of global oil and gas development in 2022.It is found that,in 2022,oil and gas fields are widely distributed worldwide,and upstream production activities continue to recover;the oil and gas reserves decrease slightly year on year,and the oil and gas reserves in sea areas increase significantly;the oil and gas production increases continuously,and the key resource countries make a significant contribution in oil and gas production growth;the oil and gas fields with production capacity not built and to be built hold abundant reserves,and their development potential will be gradually released with the economic benefits increase.Further analysis is conducted from the perspectives of global oil and gas resources continuity,geopolitical risks,potential of international cooperation,and upgrade of unconventional oil and gas technology.Finally,in view of core business domains and strategies under the new situation,the Chinese oil companies are recommended to:(1)keep a foothold in onshore conventional oil and gas development by virtue of their comparative advantages and learning from other’s experience in cooperation;(2)carry out pilot tests on development adjustment,and deepen the international cooperation in enhanced oil/gas recovery;(3)improve the oil and gas operation capabilities in sea areas to transform from follower as minority shareholder to joint venture and then to independent operations;and(4)seek appropriate ways for shale oil/gas development to reduce the dependence on foreign oil and gas.
文摘With the advent of the era of big data and artificial intelligence, new infrastructure construction(NIC) has attracted the attention of many countries. The development of NIC provides an opportunity to bridge the digital divide and narrow the regional gap,providing continuous impetus to further promote economic development. Here, we considered 31 provincial-level administrative units in China(not including Hong Kong, Macao, and Taiwan of China due to data unavailable) and established comprehensive evaluation indicators for the development potential of NIC. Afterward, we used the entropy-weight TOPSIS model to determine the development potential of NIC and analyze its spatio-temporal evolution characteristics. Furthermore, the GeoDetector model was applied to explore the driving mechanism of the NIC development potential. The conclusions were as follows: (1) The Chinese NIC development potential is generally low. The eastern China was the region with the highest development potential year by year, while the development potential in the central China was found to be in an accelerating phase. (2) The evolution of the Chinese NIC development potential’s spatial pattern has been characterized by an inland extension and coastal agglomeration. Moreover, we identified a superior development zone, a rising development zone, an inferior development zone, and a declining development zone. (3) The scope of Chinese NIC development potential agglomeration areas has gradually expanded and its degree has gradually deepened. The range of high-value agglomeration in eastern area gradually expanded and its degree gradually deepened. (4) Investment in innovative talents appears as the core factor affecting the Chinese NIC development potential. Whether acting alone or synergistically with other factors, its promoting effect on Chinese NIC development potential is the strongest.
基金Project supported by the National Science and Technology Major Project"Development Demonstration Engineeing of Large Low-Permability Lithologic and Stratigraphic Oil and Gas Reservoirs in the Ordos Basin"(No.2016ZX05050)the PetoChina's Science and Technology Major Project,"Study on Production Stabilization and EOR Technologics of Changqing Gas Field"(No.2016E-0509).
文摘At present,natural gas accounts for a low proportion in China's primary energy consumption structure and is highly dependent on foreign sources.Changqing gas province of the Ordos Basin where PetroChina Changqing Oilfield Company(referred to as Changqing Oilfield)is located is one of China's four major natural gas production bases.It bears the important responsibility for ensuring people's livelihood and promoting the healthy development of society economy.In recent years,Changqing Oilfield actively implements national instructive spirit on vigorously promoting domestic oil and gas exploration and development strength and formulates the secondary acceleration development strategies.Its annual natural gas production in 2020 reaches 448.5×10^(8) m^(3) and oil and gas equivalent exceeds 6000×10^(4) t,tamping its important position of“Western Daqing”in this industry.In order to further promote the continuous stable production and realize the goal of quality and efficiency improvement in Changqing gas province,this paper analyzes the situations and challenges of natural gas development in this gas province,prepares the development technological countermeasures and forecast the natural gas development prospect.And the following research results are obtained.First,the natural gas exploration and development in Changqing gas province is divided into four stages and the main technologies for the development of low-permeability carbonate gas reservoir,low-permeability sandstone gas reservoir and tight sandstone gas reservoir are formed.Second,the natural gas development in Changqing gas province faces six challenges,such as low reserve production degree,sharp decline of production rates and complex distribution of remaining undeveloped reserves of developed gas fields.And twenty-six development technological countermeasures are put forward correspondingly,such as well pattern thickening,extension and reserve increase,secondary production layer potential tapping and fine gas well management.Third,the development direction and goal of natural gas development in Changqing gas province is to pay equal attention to the stable production of old gas fields and the production increase of new areas and carry out conventional gas and unconventional gas research simultaneously.In conclusion,the annual natural gas production of Changqing gas province will maintain a sound momentum of steady growth and will exceed 500×10^(8) m^(3) at the end of the 14th Five-Year Plan and maintain at a stable level for a long term,which is conducive to the optimization of domestic energy consumption structure and realization of“carbon peak and carbon neutrality”.
文摘Microorganisms, regardless of whether pathogenic or not, may cause enormous economic losses due to adverse effects on human and animal health, or by damaging the quality of the agricultural and food products. Based on these effects, the development of prompt molecular methods and their involvement in the practical pathogen diagnostic diagnostics is more than actual. This paper is focused on the evaluation of easy-to-perform and highly budget-friendly, PCR-related DNA purification protocols for diagnostic purposes especially in water or similar simple matrices. The slight modifications of earlier described DNA isolation methods, which rely on chelate exchange resin and/or ethanol-sodium-based heat lysis, we reevaluated in comparison with a widely used commercial kit. The efficiency of DNA purification techniques was assessed from Gramnegative as well as Gram-positive bacteria and yeast using quantitative PCR. The effectivity of different methods tested may vary depending on the bacterial or yeast species in question. Nevertheless, in our hands, the chelate exchange resin-based methods were found to be the most robust and/or satisfying at least by an acceptable reproducibility rate. Our presented results support the potential of low-cost but still sensitive molecular microbe detection procedures consisting of only a few pipetting steps resulting in good reproducibility and the least possible environmental burden, serving as a good starting point for developments of matrix-specific processes and methods.
