A total of 45 alkylbenzenes were detected and identified in crude oils with different depositional environments and thermal maturities from the Tarim Basin,Beibuwan Basin,and Songliao Basin using comprehensive two-dim...A total of 45 alkylbenzenes were detected and identified in crude oils with different depositional environments and thermal maturities from the Tarim Basin,Beibuwan Basin,and Songliao Basin using comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry(GC×GCTOFMS).By analyzing the distribution characteristics of C0-C5alkylbenzenes,it is found that the content of some alkylbenzenes varies greatly in crude oils.Based on the distribution characteristics of 1,2,4,5-tetramethylbenzene(Te MB)and 1,2,3,4-Te MB,the ratio of 1,2,4,5-Te MB to 1,2,3,4-Te MB is proposed to indicate the organic matter origin and depositional environment of ancient sediments.Oil samples originated mainly from lower hydrobiont,algae,bacteria and source rocks deposited under reducing/anoxic conditions have low 1,2,4,5-/1,2,3,4-Te MB values(less than 0.6),while oil samples originated mainly from terrestrial higher plants and source rocks deposited under oxic/sub-oxic conditions have higher 1,2,4,5-/1,2,3,4-Te MB values(greater than 1.0).The significant difference of 1,2,4,5-/1,2,3,4-Te MB values is controlled by 1,2,4,5-Te MB content.1,2,4,5-Te MB content in oils derived from source rocks deposited in oxidized sedimentary environment(greater than 1.0 mg/g whole oil)is higher than that in oils from source rocks deposited in reduced sedimentary environment(less than 1.0 mg/g whole oil).1,2,4,5-/1,2,3,4-Te MB ratio might not or slightly be affected by evaporative fractionation,biodegradation and thermal maturity.1,2,4,5-/1,2,3,4-Te MB ratio and 1,2,4,5-Te MB content can be used as supplementary parameter for the identification of sedimentary environment and organic matter input.It should be noted that compared to the identification of organic matter sources,the 1,2,4,5-/1,2,3,4-Te MB parameter is more effective in identifying sedimentary environments.展开更多
Metallic iron nanoparticles(npFe0)are widespread on the Moon,and their accumulation changes the optical spectra of the lunar surface over time.How the surface color changes largely depends on the size of npFe0:smaller...Metallic iron nanoparticles(npFe0)are widespread on the Moon,and their accumulation changes the optical spectra of the lunar surface over time.How the surface color changes largely depends on the size of npFe0:smaller npFe0 reddens the reflectance spectra,while larger npFe0 causes darkening.The resultant color variations greatly complicate remote sensing studies,posing long-term puzzles to astronomers.展开更多
BACKGROUND China’s Behavioral Risk Factor Surveillance System(BRFSS)originated from the World Bankfunded HealthⅦLoan Project in the 1990s,which conducted behavioral risk factor surveillance in seven cities and one p...BACKGROUND China’s Behavioral Risk Factor Surveillance System(BRFSS)originated from the World Bankfunded HealthⅦLoan Project in the 1990s,which conducted behavioral risk factor surveillance in seven cities and one province^([1]).Drawing on the World Health Organization’s(WHO)STEPwise approach to surveillance(STEPs)and the U.S.Behavioral Risk Factor Surveillance System(BRFSS)^([2,3]).展开更多
Litchi (Litchi chinensis Sonn.) is a well-known tropical and subtropical woody fruit that originated from southern China (Wei et al.,2017;Hu et al.,2022).Based on the development of the embryo,litchi varieties can be ...Litchi (Litchi chinensis Sonn.) is a well-known tropical and subtropical woody fruit that originated from southern China (Wei et al.,2017;Hu et al.,2022).Based on the development of the embryo,litchi varieties can be divided into three distinct groups:large-seeded cultivars,small (abortive)-seeded cultivars and partial abortive-seeded cultivars.Seedless or the reduction in seed size due to embryo abortion is a desirable trait in fruit trees as it directly influences the texture and economic value of fleshy fruits,making small (abortive)-seeded litchi cultivars the most preferred.However,in current production practices,there is no efficient method available to induce or promote high seed abortion in litchi fruit.Therefore,understanding the stenospermy mechanisms of litchi seed development is of great significance for improving agricultural practices and managing genetic resources.展开更多
By studying the light isotopic compositions of carbon,oxygen,and hydrogen,combined with previous research results on the ore-forming source of the deposit,the authors try to uncover its metallogenic origin.The δ^(18)...By studying the light isotopic compositions of carbon,oxygen,and hydrogen,combined with previous research results on the ore-forming source of the deposit,the authors try to uncover its metallogenic origin.The δ^(18)O and δ^(13)C isotope signatures of dolomite samples vary between 10.2 and 13.0‰,and between−7.2 and−5.2‰,respectively,implying that the carbon derives from the upper mantle.δD and δ^(18) O of quartz,biotite,and muscovite from diff erent ore veins of the deposit vary between−82 and−59‰,and between 11.6 and 12.4‰,respectively,implying that the metallogenic solutions are mainly magmatic.According to the relevant research results of many isotope geologists,the fractionation degree of hydrogen isotopes increases as the depth to the Earth’s core increases,and the more diff erentiated the hydrogen isotopes are,the lower their values will be.In other words,mantle-derived solutions can have extremely low hydrogen isotope values.This means that the δD‰ value−134 of the pyrrhotite sample numbered SD-34 in this article may indicate mantle-derived oreforming fl uid of the deposit.The formation of the Dashuigou tellurium deposit occurred between 91.71 and 80.19 Ma.展开更多
Anomalous origin of the left coronary artery (AOLCA) from the right sinus of Valsalva constitutes a rare congenital coronary artery anomaly. Patients with an anomalous left main coronary artery face a significantly hi...Anomalous origin of the left coronary artery (AOLCA) from the right sinus of Valsalva constitutes a rare congenital coronary artery anomaly. Patients with an anomalous left main coronary artery face a significantly higher risk of sudden cardiac death compared to those with an anomalous right coronary artery. The anomalous coronary artery traversing between the ascending aorta and the pulmonary artery markedly heightens the risk of myocardial ischemia, arrhythmia, and sudden death. Symptomatic patients often exhibit a longer intramural course of the coronary artery, which may necessitate earlier intervention or influence the choice of surgical repair method. Surgical intervention is advocated for patients with this anomaly, even in the absence of symptoms. For anomalous aortic origin of a coronary artery from the opposite sinus of Valsalva with an intramural course, coronary unroofing is the preferred revascularization procedure. This report presents a case of AOLCA originating from the right sinus of Valsalva, treated surgically using the unroofing technique for the aortic intramural segment of the anomalous coronary artery traversing between the great vessels. The unroofing technique is recommended for treating AOLCA with an extensive intramural course that does not involve the commissure.展开更多
Chinese Assam tea(Camellia sinensis var.assamica)is an important tea crop with a long history of cultivation in Yunnan,China.Despite its potential value as a genetic resource,its genetic diversity and domestication/br...Chinese Assam tea(Camellia sinensis var.assamica)is an important tea crop with a long history of cultivation in Yunnan,China.Despite its potential value as a genetic resource,its genetic diversity and domestication/breeding history remain unclear.To address this issue,we genotyped 469 ancient tea plant trees representing 26 C.sinensis var.assamica populations,plus two of its wild relatives(six and three populations of C.taliensis and C.crassicolumna,respectively)using 16 nuclear microsatellite loci.Results showed that Chinese Assam tea has a relatively high,but comparatively lower gene diversity(H_(S)=0.638)than the wild relative C.crassicolumna(H_S=0.658).Clustering in STRUCTURE indicated that Chinese Assam tea and its two wild relatives formed distinct genetic groups,with considerable interspecific introgression.The Chinese Assam tea accessions clustered into three gene pools,corresponding well with their geographic distribution.However,New Hybrids analysis indicated that 68.48%of ancient Chinese Assam tea plants from Xishuangbanna were genetic intermediates between the Puer and Lincang gene pools.In addition,10%of the ancient Chinese Assam tea individuals were found to be hybrids between Chinese Assam tea and C.taliensis.Our results suggest that Chinese Assam tea was domesticated separately in three gene pools(Puer,Lincang and Xishuangbanna)in the Mekong River valley and that the hybrids were subsequently selected during the domestication process.Although the domestication history of Chinese Assam tea in southwestern Yunnan remains complex,our results will help to identify valuable genetic resources that may be useful in future tea breeding programs.展开更多
Humans across cultures convey feelings and thoughts through music.Despite its ubiquity,the origins and evolution of music remain enigmatic.Archaeological evidence has traced the history of music back at least 40000 ye...Humans across cultures convey feelings and thoughts through music.Despite its ubiquity,the origins and evolution of music remain enigmatic.Archaeological evidence has traced the history of music back at least 40000 years ago based on prehistoric bone flutes(Fitch,2006).Comparative studies have also explored earlier histories by identifying common musical features between animals and humans(Fitch,2006).For example,songbirds exhibit categorical rhythms similar to human music(Roeske et al.,2020),and humans can recognize emotional arousal in signals across all classes of terrestrial vertebrates(Filippi et al.,2017).These findings,while surprising,align with the longstanding human perception of animal signals as music(Gray et al.,2001).The universality of music and its features intensifies the fundamental question posed by Darwin(1871):how has a behavior that is energetically costly and seemingly non-adaptive evolved to become so widespread?This question can be further divided into two sub-questions(Savage et al.,2021):(1)how do musical features contribute to the production or expressive power of music(i.e.,mechanisms),and(2)how does music benefit performers in terms of survival,reproductions,or other aspects(i.e.,functions).展开更多
The Zhongjiang gas field is a typical large gas field in terrigenous strata of the Western Sichuan Depression.It remains debatable which member of the Upper Triassic Xujiahe Formation served as the source rocks and ho...The Zhongjiang gas field is a typical large gas field in terrigenous strata of the Western Sichuan Depression.It remains debatable which member of the Upper Triassic Xujiahe Formation served as the source rocks and how significant the member contributed to the gas accumulations in the Zhongjiang gas field.In this study,we analyzed the essential characteristics of the Lower Jurassic source rocks and the geochemical features of light hydrocarbons in natural gas from the 2nd(T_(3)χ^(2))and 4th members(T_(3)χ^(4))of the Upper Triassic Xujiahe Formation(T_(3)χ),as well as the Middle Jurassic Shaximiao(J_(2)s)and Qianfoya(J_(2)q)formations.Based on this,we explored the sources of the natural gas in the Zhongjiang gas field and determined the natural gas migration patterns and their effects on the properties of light hydrocarbons in the natural gas.The results indicate that the Lower Jurassic lacustrine source rocks of the Zhongjiang gas field contain humic organic matter,with vitrinite reflectance(R_(0))values ranging from 0.86%to 0.98%.Samples meeting the criterion for effective source rocks[total organic carbon(TOC)content≥0.75%]exhibited an average TOC content of merely 1.02%,suggesting significantly lower hydrocarbon generation potential than source rocks in the underlying T3x,which show higher thermal maturity and TOC contents.For natural gas samples from T_(3)χ^(2),T_(3)χ^(4),J_(2)s,and J_(2)q reservoirs,their C_(5-7)iso-alkane content was significantly higher than their n-alkane content,and their methylcyclohexane(MCH)index ranged from 59.0%to 77.3%,indicating the predominance of methylcyclohexane in C_(7)light hydrocarbons.As indicated by the origin identification and gas-source correlation based on the geochemical features of light hydrocarbons,the natural gas in the Zhongjiang gas field is typical coal-derived gas.The gas from the primary pay zone of the Shaximiao Formation,with significantly high K_(1),(P_(2)+N_(2))/C_(7),and P_(3)/C_(7)values,predominantly originated from the 5th member of the T3x and migrated in the free phase,with a small amount possibly sourced from the Lower Jurassic source rocks.The dissolution and adsorption during gas migration led to a decrease in the aromatic content in C_(6-7)light hydrocarbons and an increase in the isoheptane values.Therefore,their effects must be considered when determining the gas origin and thermal maturity based on the aromatic content in C_(6-7) light hydrocarbons and iso-heptane values.展开更多
Based on the analysis of light hydrocarbon compositions of natural gas and regional comparison in combination with the chemical components and carbon isotopic compositions of methane,the indication of geochemical char...Based on the analysis of light hydrocarbon compositions of natural gas and regional comparison in combination with the chemical components and carbon isotopic compositions of methane,the indication of geochemical characteristics of light hydrocarbons on the migration features,dissolution and escape of natural gas from the Dongsheng gas field in the Ordos Basin is revealed,and the effect of migration on specific light hydrocarbon indexes is further discussed.The study indicates that,natural gas from the Lower Shihezi Formation(Pix)in the Dongsheng gas field displays higher iso-C5-7contents than n-C5-7contents,and the C6-7light hydrocarbons are composed of paraffins with extremely low aromatic contents(<0.4%),whereas the C7light hydrocarbons are dominated by methylcyclohexane,suggesting the characteristics of coal-derived gas with the influence by secondary alterations such as dissolution.The natural gas from the Dongsheng gas field has experienced free-phase migration from south to north and different degrees of dissolution after charging,and the gas in the Shiguhao area to the north of the Borjianghaizi fault has experienced apparent diffusion loss after accumulation.Long-distance migration in free phase results in the decrease of the relative contents of the methylcyclohexane in C7 light hydrocarbons and the toluene/n-heptane ratio,as well as the increase of the n-heptane/methylcyclohexane ratio and heptane values.The dissolution causes the increase of isoheptane values of the light hydrocarbons,whereas the diffusion loss of natural gas in the Shiguhao area results in the increase of n-C5-7contents compared to the iso-C5-7contents.展开更多
Purpose–To facilitate technical managers and field workers to master and understand the provisions of Technical Management Regulations for Railway more accurately,so as to better serve the comprehensive revision of t...Purpose–To facilitate technical managers and field workers to master and understand the provisions of Technical Management Regulations for Railway more accurately,so as to better serve the comprehensive revision of the Regulations,this paper carries out the research on the traceability and evolution of the provisions of the Regulations.Design/methodology/approach–This paper studies and analyzes the evolution of the 11th edition of the Regulations by analyzing the relevance of clauses and summarizes the historical background of the development of calendar editions of the Regulations.The basic research on the traceability and evolution of the Regulations is carried out from four aspects:the continuity of the development of the Regulations,the authority of contents,the relevance of clauses and the richness of historical materials.Findings–From the first edition of the Regulations issued by the former Ministry of Railways in 1950 to the 11th edition,there have been ten comprehensive revisions.There is a strong correlation and continuity between the calendar editions of the Regulations in terms of chapter structure and clauses.Studying the context of the terms of the Regulations is an important way to understand and master the current clauses of the Regulations.Originality/value–Through the research on the traceability and evolution of the clauses of the Regulations,one is to explore the context of the development of railway technical equipment in China,the other is to clarify the historical background when the provisions were formulated and the third is to trace the development and evolution of the provisions.The revision of the Regulations is based on an accurate grasp of the context of the provisions,which can effectively judge the possible security risks caused by the revision of the provisions and avoid the possible risks in field implementation from the source.展开更多
“Plasmas” up to a kilometer in size and behaving similarly to multicellular organisms have been filmed on 10 separate NASA space shuttle missions, over 200 miles above Earth within the thermosphere. These self-illum...“Plasmas” up to a kilometer in size and behaving similarly to multicellular organisms have been filmed on 10 separate NASA space shuttle missions, over 200 miles above Earth within the thermosphere. These self-illuminated “plasmas” are attracted to and may “feed on” electromagnetic radiation. They have different morphologies: 1) cone, 2) cloud, 3) donut, 4) spherical-cylindrical;and have been filmed flying towards and descending from the thermosphere into thunderstorms;congregating by the hundreds and interacting with satellites generating electromagnetic activity;approaching the Space Shuttles. Computerized analysis of flight path trajectories documents these plasmas travel at different velocities from different directions and change their angle of trajectory making 45°, 90°, and 180° shifts and follow each other. They’ve been filmed accelerating, slowing down, stopping, congregating, engaging in “hunter-predatory” behavior and intersecting plasmas leaving a plasma dust trail in their wake. Similar life-like behaviors have been demonstrated by plasmas created experimentally. “Plasmas” may have been photographed in the 1940s by WWII pilots (identified as “Foo fighters”);repeatedly observed and filmed by astronauts and military pilots and classified as Unidentified Aerial—Anomalous Phenomenon. Plasmas are not biological but may represent a form of pre-life that via the incorporation of elements common in space, could result in the synthesis of RNA. Plasmas constitute a fourth state of matter, are attracted to electromagnetic activity, and when observed in the lower atmosphere likely account for many of the UFO-UAP sightings over the centuries.展开更多
The Minnan dialect,is characterized by its gentle tone and fluid rhythm.This dialect,with its rich history,has undergone significant evolution over the centuries.The earliest origins of the Minnan dialect can be trace...The Minnan dialect,is characterized by its gentle tone and fluid rhythm.This dialect,with its rich history,has undergone significant evolution over the centuries.The earliest origins of the Minnan dialect can be traced back to the Shang Dynasty,with its development linked to the Yellow River and the Luo River basin during the Western Jin Dynasty.展开更多
In order to promote the exchange of Chinese culture with foreign countries,translators bear an important mission in the process of cross-cultural communication.Although there are cultural differences,we can achieve cu...In order to promote the exchange of Chinese culture with foreign countries,translators bear an important mission in the process of cross-cultural communication.Although there are cultural differences,we can achieve cultural dissemination and exchange through continuous cultural dialogue.As an important way for foreign scholars to understand the history of the Shang and Zhou Dynasties in China,the translation of historical texts is crucial.Multiple typical cases are selected under the guidance of the translation theory of compensation to use relevant methods or techniques from the three levels of language,culture,and aesthetics to compensate for the loss of Li Xueqin’s The Origin of Ancient Chinese Civilization in English translation proofreading.展开更多
Overpressure is significant to the exploration and exploitation of petroleum due to its influence on hydrocarbon accumulation and drilling strategies.The deep-burial hydrocarbon reservoirs of Jurassic strata in the ce...Overpressure is significant to the exploration and exploitation of petroleum due to its influence on hydrocarbon accumulation and drilling strategies.The deep-burial hydrocarbon reservoirs of Jurassic strata in the central Junggar Basin are characterized by intensive overpressure,whose origins are complex and still unclear.In this study,Bowers'method and sonic velocity-density crossplot method based on well logging data were used as a combination for overpressure judgements in geophysics.Furthermore,the corresponding geological processes were analysed in quality and quantity to provide a rational comprehension of the overpressure origins and the model of overpressure evolution and hy-drocarbon accumulation processes.The results showed that hydrocarbon generation in the Jurassic source rocks led to overpressure in the mudstones,while hydrocarbon generation in Permian source rocks led to overpressure in the sandstone reservoirs in Jurassic strata by vertical pressure transfer.The burial and thermal history indicated that the aquathermal effect of pore fluids by temperature increase in deep strata is also an important origin of overpressure,while disequilibrium compaction may not be the dominant cause for the overpressure in deep-buried strata.Furthermore,the continuous tectonic compression in both the north-south and west-east trends from the Jurassic period to the present may also have enhanced the overpressure in deep strata.Meanwhile,the developed faults formed by intensive tectonic compression led to pressure transfer from source rocks to the Jurassic reservoirs.Overpressured geofluids with hydrocarbons migrated to sandstone reservoirs and aggravated the over-pressure in the Jurassic strata.To conclude,the intensive overpressure in the central Junggar Basin is attributed to the combination of multiple mechanisms,including hydrocarbon generation,the aqua-thermal effect,tectonic compression and pressure transfer.Furthermore,the developed overpressure indicated hydrocarbon migration and accumulation processes and the potential of oil and gas reservoirs in deeply buried strata.We hope this study will provide a systematic research concept for overpressure origin analysis and provide guidance for petroleum exploration and exploitation in deep-buried strata.展开更多
This study used Topological Weighted Centroid (TWC) to analyze the Coronavirus outbreak in Brazil. This analysis only uses latitude and longitude in formation of the capitals with the confirmed cases on May 24, 2020 t...This study used Topological Weighted Centroid (TWC) to analyze the Coronavirus outbreak in Brazil. This analysis only uses latitude and longitude in formation of the capitals with the confirmed cases on May 24, 2020 to illustrate the usefulness of TWC though any date could have been used. There are three types of TWC analyses, each type having five associated algorithms that produce fifteen maps, TWC-Original, TWC-Frequency and TWC-Windowing. We focus on TWC-Original to illustrate our approach. The TWC method without using the transportation information predicts the network for COVID-19 outbreak that matches very well with the main radial transportation routes network in Brazil.展开更多
The Liaohe River basin in northeastern China occupies an important geographical position connecting Northeast Asia and the Central Plains.Millennia ago,it witnessed the convergence of farming,fishing,hunting,and nomad...The Liaohe River basin in northeastern China occupies an important geographical position connecting Northeast Asia and the Central Plains.Millennia ago,it witnessed the convergence of farming,fishing,hunting,and nomadic cultures and the coexistence and flourishing of multiple peoples.Archaeological excavations and research on this area show that as early as the Neolithic period,the indigenous Hongshan Culture had already embraced the dawn of civilization.Traces of early city forms were discovered at the Niuheliang site dating from the late Hongshan period,providing archaeological evidence on the 5,000 years of history of Chinese civilization.In academic circles,Hongshan Culture is considered the“tap root”of Chinese civilization,from which the core traditions of Chinese civilization such as respecting heaven and ancestors and worshiping the dragon and jade originated.This issue’s“Focus”section is dedicated to tracing the origins of Chinese civilization by focusing on the origins and characteristics of Hongshan Culture as well as its fusion with other civilizations around the world.We hope to shed light on the far reaching,time-honored Chinese culture and provide a fresh perspective for readers to understand the development of human civilization.展开更多
The Central Axis of Beijing embodies the cultural spirit and urban planning ingenuity of an ancient nation.WITH the release of the Beijing Central Axis panoramic map by Beijing Municipal Cultural Heritage Bureau in la...The Central Axis of Beijing embodies the cultural spirit and urban planning ingenuity of an ancient nation.WITH the release of the Beijing Central Axis panoramic map by Beijing Municipal Cultural Heritage Bureau in late November,2022,together with the plan for its protection and management in the coming decade.展开更多
Indirect development with an intermediate larva exists in all major animal lineages1, which makes larvae central to mostscenarios of animal evolution2-11. Yet how larvae evolved remains disputed. Here we show that tem...Indirect development with an intermediate larva exists in all major animal lineages1, which makes larvae central to mostscenarios of animal evolution2-11. Yet how larvae evolved remains disputed. Here we show that temporal shifts (that is,heterochronies) in trunk formation underpin the diversification of larvae and bilaterian life cycles. We performed chromosomescalegenome sequencing in the annelid Owenia fusiformis with transcriptomic and epigenomic profiling during the life cycles ofthis and two other annelids. We found that trunk development is deferred to pre-metamorphic stages in the feeding larva of O.fusiformis but starts after gastrulation in the non-feeding larva with gradual metamorphosis of Capitella teleta and the directdeveloping embryo of Dimorphilus gyrociliatus. Accordingly, the embryos of O. fusiformis develop first into an enlarged anteriordomain that forms larval tissues and the adult head12. Notably, this also occurs in the so-called 'head larvae' of other bilaterians13-17, with which the O. fusiformis larva shows extensive transcriptomic similarities. Together, our findings suggest that the temporaldecoupling of head and trunk formation, as maximally observed in head larvae, facilitated larval evolution in Bilateria. Thisdiverges from prevailing scenarios that propose either co-option9,10 or innovation11 of gene regulatory programmes to explainlarva and adult origins.展开更多
基金supported by Doctor’s Scientific Research Initiation Project of Yan’an University(YAU202213093)National Natural Science Foundation of China(Grant No.41503029)。
文摘A total of 45 alkylbenzenes were detected and identified in crude oils with different depositional environments and thermal maturities from the Tarim Basin,Beibuwan Basin,and Songliao Basin using comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry(GC×GCTOFMS).By analyzing the distribution characteristics of C0-C5alkylbenzenes,it is found that the content of some alkylbenzenes varies greatly in crude oils.Based on the distribution characteristics of 1,2,4,5-tetramethylbenzene(Te MB)and 1,2,3,4-Te MB,the ratio of 1,2,4,5-Te MB to 1,2,3,4-Te MB is proposed to indicate the organic matter origin and depositional environment of ancient sediments.Oil samples originated mainly from lower hydrobiont,algae,bacteria and source rocks deposited under reducing/anoxic conditions have low 1,2,4,5-/1,2,3,4-Te MB values(less than 0.6),while oil samples originated mainly from terrestrial higher plants and source rocks deposited under oxic/sub-oxic conditions have higher 1,2,4,5-/1,2,3,4-Te MB values(greater than 1.0).The significant difference of 1,2,4,5-/1,2,3,4-Te MB values is controlled by 1,2,4,5-Te MB content.1,2,4,5-Te MB content in oils derived from source rocks deposited in oxidized sedimentary environment(greater than 1.0 mg/g whole oil)is higher than that in oils from source rocks deposited in reduced sedimentary environment(less than 1.0 mg/g whole oil).1,2,4,5-/1,2,3,4-Te MB ratio might not or slightly be affected by evaporative fractionation,biodegradation and thermal maturity.1,2,4,5-/1,2,3,4-Te MB ratio and 1,2,4,5-Te MB content can be used as supplementary parameter for the identification of sedimentary environment and organic matter input.It should be noted that compared to the identification of organic matter sources,the 1,2,4,5-/1,2,3,4-Te MB parameter is more effective in identifying sedimentary environments.
基金supported by the National Natural Science Foundation of Chinathe CASthe National Natural Science Foundation of Guangdong Province
文摘Metallic iron nanoparticles(npFe0)are widespread on the Moon,and their accumulation changes the optical spectra of the lunar surface over time.How the surface color changes largely depends on the size of npFe0:smaller npFe0 reddens the reflectance spectra,while larger npFe0 causes darkening.The resultant color variations greatly complicate remote sensing studies,posing long-term puzzles to astronomers.
基金supported by the National Key R&D Program[2018YFC1311702,2018YFC1311706]。
文摘BACKGROUND China’s Behavioral Risk Factor Surveillance System(BRFSS)originated from the World Bankfunded HealthⅦLoan Project in the 1990s,which conducted behavioral risk factor surveillance in seven cities and one province^([1]).Drawing on the World Health Organization’s(WHO)STEPwise approach to surveillance(STEPs)and the U.S.Behavioral Risk Factor Surveillance System(BRFSS)^([2,3]).
基金supported by grants from the Laboratory of Lingnan Modern Agriculture Project (Grant No.NZ NT2021004)China Litchi and Longan Industry Technology Research System (Grant No.CARS-32-07)。
文摘Litchi (Litchi chinensis Sonn.) is a well-known tropical and subtropical woody fruit that originated from southern China (Wei et al.,2017;Hu et al.,2022).Based on the development of the embryo,litchi varieties can be divided into three distinct groups:large-seeded cultivars,small (abortive)-seeded cultivars and partial abortive-seeded cultivars.Seedless or the reduction in seed size due to embryo abortion is a desirable trait in fruit trees as it directly influences the texture and economic value of fleshy fruits,making small (abortive)-seeded litchi cultivars the most preferred.However,in current production practices,there is no efficient method available to induce or promote high seed abortion in litchi fruit.Therefore,understanding the stenospermy mechanisms of litchi seed development is of great significance for improving agricultural practices and managing genetic resources.
基金Support for this study was received from Orient Resources Ltd.in Canada,Wuhan Institute of Technology,China,and College of Earth Sciences,Jilin University,China.
文摘By studying the light isotopic compositions of carbon,oxygen,and hydrogen,combined with previous research results on the ore-forming source of the deposit,the authors try to uncover its metallogenic origin.The δ^(18)O and δ^(13)C isotope signatures of dolomite samples vary between 10.2 and 13.0‰,and between−7.2 and−5.2‰,respectively,implying that the carbon derives from the upper mantle.δD and δ^(18) O of quartz,biotite,and muscovite from diff erent ore veins of the deposit vary between−82 and−59‰,and between 11.6 and 12.4‰,respectively,implying that the metallogenic solutions are mainly magmatic.According to the relevant research results of many isotope geologists,the fractionation degree of hydrogen isotopes increases as the depth to the Earth’s core increases,and the more diff erentiated the hydrogen isotopes are,the lower their values will be.In other words,mantle-derived solutions can have extremely low hydrogen isotope values.This means that the δD‰ value−134 of the pyrrhotite sample numbered SD-34 in this article may indicate mantle-derived oreforming fl uid of the deposit.The formation of the Dashuigou tellurium deposit occurred between 91.71 and 80.19 Ma.
文摘Anomalous origin of the left coronary artery (AOLCA) from the right sinus of Valsalva constitutes a rare congenital coronary artery anomaly. Patients with an anomalous left main coronary artery face a significantly higher risk of sudden cardiac death compared to those with an anomalous right coronary artery. The anomalous coronary artery traversing between the ascending aorta and the pulmonary artery markedly heightens the risk of myocardial ischemia, arrhythmia, and sudden death. Symptomatic patients often exhibit a longer intramural course of the coronary artery, which may necessitate earlier intervention or influence the choice of surgical repair method. Surgical intervention is advocated for patients with this anomaly, even in the absence of symptoms. For anomalous aortic origin of a coronary artery from the opposite sinus of Valsalva with an intramural course, coronary unroofing is the preferred revascularization procedure. This report presents a case of AOLCA originating from the right sinus of Valsalva, treated surgically using the unroofing technique for the aortic intramural segment of the anomalous coronary artery traversing between the great vessels. The unroofing technique is recommended for treating AOLCA with an extensive intramural course that does not involve the commissure.
基金supported by funds from the National Natural Science Foundation of China(31970363,31161140350)the Key Basic Research Program of Yunnan Province,China(202101BC070003)supported by the Scottish Government’s Rural and Environment Science and Analytical Services division。
文摘Chinese Assam tea(Camellia sinensis var.assamica)is an important tea crop with a long history of cultivation in Yunnan,China.Despite its potential value as a genetic resource,its genetic diversity and domestication/breeding history remain unclear.To address this issue,we genotyped 469 ancient tea plant trees representing 26 C.sinensis var.assamica populations,plus two of its wild relatives(six and three populations of C.taliensis and C.crassicolumna,respectively)using 16 nuclear microsatellite loci.Results showed that Chinese Assam tea has a relatively high,but comparatively lower gene diversity(H_(S)=0.638)than the wild relative C.crassicolumna(H_S=0.658).Clustering in STRUCTURE indicated that Chinese Assam tea and its two wild relatives formed distinct genetic groups,with considerable interspecific introgression.The Chinese Assam tea accessions clustered into three gene pools,corresponding well with their geographic distribution.However,New Hybrids analysis indicated that 68.48%of ancient Chinese Assam tea plants from Xishuangbanna were genetic intermediates between the Puer and Lincang gene pools.In addition,10%of the ancient Chinese Assam tea individuals were found to be hybrids between Chinese Assam tea and C.taliensis.Our results suggest that Chinese Assam tea was domesticated separately in three gene pools(Puer,Lincang and Xishuangbanna)in the Mekong River valley and that the hybrids were subsequently selected during the domestication process.Although the domestication history of Chinese Assam tea in southwestern Yunnan remains complex,our results will help to identify valuable genetic resources that may be useful in future tea breeding programs.
文摘Humans across cultures convey feelings and thoughts through music.Despite its ubiquity,the origins and evolution of music remain enigmatic.Archaeological evidence has traced the history of music back at least 40000 years ago based on prehistoric bone flutes(Fitch,2006).Comparative studies have also explored earlier histories by identifying common musical features between animals and humans(Fitch,2006).For example,songbirds exhibit categorical rhythms similar to human music(Roeske et al.,2020),and humans can recognize emotional arousal in signals across all classes of terrestrial vertebrates(Filippi et al.,2017).These findings,while surprising,align with the longstanding human perception of animal signals as music(Gray et al.,2001).The universality of music and its features intensifies the fundamental question posed by Darwin(1871):how has a behavior that is energetically costly and seemingly non-adaptive evolved to become so widespread?This question can be further divided into two sub-questions(Savage et al.,2021):(1)how do musical features contribute to the production or expressive power of music(i.e.,mechanisms),and(2)how does music benefit performers in terms of survival,reproductions,or other aspects(i.e.,functions).
基金funded by the National Natural Science Foundation of China(No.42172149,No.U2244209)the SINOPEC Science and Technology Project(No.P22132,No.P21077-1).
文摘The Zhongjiang gas field is a typical large gas field in terrigenous strata of the Western Sichuan Depression.It remains debatable which member of the Upper Triassic Xujiahe Formation served as the source rocks and how significant the member contributed to the gas accumulations in the Zhongjiang gas field.In this study,we analyzed the essential characteristics of the Lower Jurassic source rocks and the geochemical features of light hydrocarbons in natural gas from the 2nd(T_(3)χ^(2))and 4th members(T_(3)χ^(4))of the Upper Triassic Xujiahe Formation(T_(3)χ),as well as the Middle Jurassic Shaximiao(J_(2)s)and Qianfoya(J_(2)q)formations.Based on this,we explored the sources of the natural gas in the Zhongjiang gas field and determined the natural gas migration patterns and their effects on the properties of light hydrocarbons in the natural gas.The results indicate that the Lower Jurassic lacustrine source rocks of the Zhongjiang gas field contain humic organic matter,with vitrinite reflectance(R_(0))values ranging from 0.86%to 0.98%.Samples meeting the criterion for effective source rocks[total organic carbon(TOC)content≥0.75%]exhibited an average TOC content of merely 1.02%,suggesting significantly lower hydrocarbon generation potential than source rocks in the underlying T3x,which show higher thermal maturity and TOC contents.For natural gas samples from T_(3)χ^(2),T_(3)χ^(4),J_(2)s,and J_(2)q reservoirs,their C_(5-7)iso-alkane content was significantly higher than their n-alkane content,and their methylcyclohexane(MCH)index ranged from 59.0%to 77.3%,indicating the predominance of methylcyclohexane in C_(7)light hydrocarbons.As indicated by the origin identification and gas-source correlation based on the geochemical features of light hydrocarbons,the natural gas in the Zhongjiang gas field is typical coal-derived gas.The gas from the primary pay zone of the Shaximiao Formation,with significantly high K_(1),(P_(2)+N_(2))/C_(7),and P_(3)/C_(7)values,predominantly originated from the 5th member of the T3x and migrated in the free phase,with a small amount possibly sourced from the Lower Jurassic source rocks.The dissolution and adsorption during gas migration led to a decrease in the aromatic content in C_(6-7)light hydrocarbons and an increase in the isoheptane values.Therefore,their effects must be considered when determining the gas origin and thermal maturity based on the aromatic content in C_(6-7) light hydrocarbons and iso-heptane values.
基金Supported by the National Natural Science Foundation of China(42172149,U2244209)Sinopec Science and Technology Research Project(P23230,P22132)。
文摘Based on the analysis of light hydrocarbon compositions of natural gas and regional comparison in combination with the chemical components and carbon isotopic compositions of methane,the indication of geochemical characteristics of light hydrocarbons on the migration features,dissolution and escape of natural gas from the Dongsheng gas field in the Ordos Basin is revealed,and the effect of migration on specific light hydrocarbon indexes is further discussed.The study indicates that,natural gas from the Lower Shihezi Formation(Pix)in the Dongsheng gas field displays higher iso-C5-7contents than n-C5-7contents,and the C6-7light hydrocarbons are composed of paraffins with extremely low aromatic contents(<0.4%),whereas the C7light hydrocarbons are dominated by methylcyclohexane,suggesting the characteristics of coal-derived gas with the influence by secondary alterations such as dissolution.The natural gas from the Dongsheng gas field has experienced free-phase migration from south to north and different degrees of dissolution after charging,and the gas in the Shiguhao area to the north of the Borjianghaizi fault has experienced apparent diffusion loss after accumulation.Long-distance migration in free phase results in the decrease of the relative contents of the methylcyclohexane in C7 light hydrocarbons and the toluene/n-heptane ratio,as well as the increase of the n-heptane/methylcyclohexane ratio and heptane values.The dissolution causes the increase of isoheptane values of the light hydrocarbons,whereas the diffusion loss of natural gas in the Shiguhao area results in the increase of n-C5-7contents compared to the iso-C5-7contents.
基金funded by Revision and Key Technical Research on Railway Technical Management Regulation(P2023B001).
文摘Purpose–To facilitate technical managers and field workers to master and understand the provisions of Technical Management Regulations for Railway more accurately,so as to better serve the comprehensive revision of the Regulations,this paper carries out the research on the traceability and evolution of the provisions of the Regulations.Design/methodology/approach–This paper studies and analyzes the evolution of the 11th edition of the Regulations by analyzing the relevance of clauses and summarizes the historical background of the development of calendar editions of the Regulations.The basic research on the traceability and evolution of the Regulations is carried out from four aspects:the continuity of the development of the Regulations,the authority of contents,the relevance of clauses and the richness of historical materials.Findings–From the first edition of the Regulations issued by the former Ministry of Railways in 1950 to the 11th edition,there have been ten comprehensive revisions.There is a strong correlation and continuity between the calendar editions of the Regulations in terms of chapter structure and clauses.Studying the context of the terms of the Regulations is an important way to understand and master the current clauses of the Regulations.Originality/value–Through the research on the traceability and evolution of the clauses of the Regulations,one is to explore the context of the development of railway technical equipment in China,the other is to clarify the historical background when the provisions were formulated and the third is to trace the development and evolution of the provisions.The revision of the Regulations is based on an accurate grasp of the context of the provisions,which can effectively judge the possible security risks caused by the revision of the provisions and avoid the possible risks in field implementation from the source.
文摘“Plasmas” up to a kilometer in size and behaving similarly to multicellular organisms have been filmed on 10 separate NASA space shuttle missions, over 200 miles above Earth within the thermosphere. These self-illuminated “plasmas” are attracted to and may “feed on” electromagnetic radiation. They have different morphologies: 1) cone, 2) cloud, 3) donut, 4) spherical-cylindrical;and have been filmed flying towards and descending from the thermosphere into thunderstorms;congregating by the hundreds and interacting with satellites generating electromagnetic activity;approaching the Space Shuttles. Computerized analysis of flight path trajectories documents these plasmas travel at different velocities from different directions and change their angle of trajectory making 45°, 90°, and 180° shifts and follow each other. They’ve been filmed accelerating, slowing down, stopping, congregating, engaging in “hunter-predatory” behavior and intersecting plasmas leaving a plasma dust trail in their wake. Similar life-like behaviors have been demonstrated by plasmas created experimentally. “Plasmas” may have been photographed in the 1940s by WWII pilots (identified as “Foo fighters”);repeatedly observed and filmed by astronauts and military pilots and classified as Unidentified Aerial—Anomalous Phenomenon. Plasmas are not biological but may represent a form of pre-life that via the incorporation of elements common in space, could result in the synthesis of RNA. Plasmas constitute a fourth state of matter, are attracted to electromagnetic activity, and when observed in the lower atmosphere likely account for many of the UFO-UAP sightings over the centuries.
文摘The Minnan dialect,is characterized by its gentle tone and fluid rhythm.This dialect,with its rich history,has undergone significant evolution over the centuries.The earliest origins of the Minnan dialect can be traced back to the Shang Dynasty,with its development linked to the Yellow River and the Luo River basin during the Western Jin Dynasty.
文摘In order to promote the exchange of Chinese culture with foreign countries,translators bear an important mission in the process of cross-cultural communication.Although there are cultural differences,we can achieve cultural dissemination and exchange through continuous cultural dialogue.As an important way for foreign scholars to understand the history of the Shang and Zhou Dynasties in China,the translation of historical texts is crucial.Multiple typical cases are selected under the guidance of the translation theory of compensation to use relevant methods or techniques from the three levels of language,culture,and aesthetics to compensate for the loss of Li Xueqin’s The Origin of Ancient Chinese Civilization in English translation proofreading.
基金supported by the National Natural Science Foundation of China(Grant No.41972124)。
文摘Overpressure is significant to the exploration and exploitation of petroleum due to its influence on hydrocarbon accumulation and drilling strategies.The deep-burial hydrocarbon reservoirs of Jurassic strata in the central Junggar Basin are characterized by intensive overpressure,whose origins are complex and still unclear.In this study,Bowers'method and sonic velocity-density crossplot method based on well logging data were used as a combination for overpressure judgements in geophysics.Furthermore,the corresponding geological processes were analysed in quality and quantity to provide a rational comprehension of the overpressure origins and the model of overpressure evolution and hy-drocarbon accumulation processes.The results showed that hydrocarbon generation in the Jurassic source rocks led to overpressure in the mudstones,while hydrocarbon generation in Permian source rocks led to overpressure in the sandstone reservoirs in Jurassic strata by vertical pressure transfer.The burial and thermal history indicated that the aquathermal effect of pore fluids by temperature increase in deep strata is also an important origin of overpressure,while disequilibrium compaction may not be the dominant cause for the overpressure in deep-buried strata.Furthermore,the continuous tectonic compression in both the north-south and west-east trends from the Jurassic period to the present may also have enhanced the overpressure in deep strata.Meanwhile,the developed faults formed by intensive tectonic compression led to pressure transfer from source rocks to the Jurassic reservoirs.Overpressured geofluids with hydrocarbons migrated to sandstone reservoirs and aggravated the over-pressure in the Jurassic strata.To conclude,the intensive overpressure in the central Junggar Basin is attributed to the combination of multiple mechanisms,including hydrocarbon generation,the aqua-thermal effect,tectonic compression and pressure transfer.Furthermore,the developed overpressure indicated hydrocarbon migration and accumulation processes and the potential of oil and gas reservoirs in deeply buried strata.We hope this study will provide a systematic research concept for overpressure origin analysis and provide guidance for petroleum exploration and exploitation in deep-buried strata.
文摘This study used Topological Weighted Centroid (TWC) to analyze the Coronavirus outbreak in Brazil. This analysis only uses latitude and longitude in formation of the capitals with the confirmed cases on May 24, 2020 to illustrate the usefulness of TWC though any date could have been used. There are three types of TWC analyses, each type having five associated algorithms that produce fifteen maps, TWC-Original, TWC-Frequency and TWC-Windowing. We focus on TWC-Original to illustrate our approach. The TWC method without using the transportation information predicts the network for COVID-19 outbreak that matches very well with the main radial transportation routes network in Brazil.
文摘The Liaohe River basin in northeastern China occupies an important geographical position connecting Northeast Asia and the Central Plains.Millennia ago,it witnessed the convergence of farming,fishing,hunting,and nomadic cultures and the coexistence and flourishing of multiple peoples.Archaeological excavations and research on this area show that as early as the Neolithic period,the indigenous Hongshan Culture had already embraced the dawn of civilization.Traces of early city forms were discovered at the Niuheliang site dating from the late Hongshan period,providing archaeological evidence on the 5,000 years of history of Chinese civilization.In academic circles,Hongshan Culture is considered the“tap root”of Chinese civilization,from which the core traditions of Chinese civilization such as respecting heaven and ancestors and worshiping the dragon and jade originated.This issue’s“Focus”section is dedicated to tracing the origins of Chinese civilization by focusing on the origins and characteristics of Hongshan Culture as well as its fusion with other civilizations around the world.We hope to shed light on the far reaching,time-honored Chinese culture and provide a fresh perspective for readers to understand the development of human civilization.
文摘The Central Axis of Beijing embodies the cultural spirit and urban planning ingenuity of an ancient nation.WITH the release of the Beijing Central Axis panoramic map by Beijing Municipal Cultural Heritage Bureau in late November,2022,together with the plan for its protection and management in the coming decade.
文摘Indirect development with an intermediate larva exists in all major animal lineages1, which makes larvae central to mostscenarios of animal evolution2-11. Yet how larvae evolved remains disputed. Here we show that temporal shifts (that is,heterochronies) in trunk formation underpin the diversification of larvae and bilaterian life cycles. We performed chromosomescalegenome sequencing in the annelid Owenia fusiformis with transcriptomic and epigenomic profiling during the life cycles ofthis and two other annelids. We found that trunk development is deferred to pre-metamorphic stages in the feeding larva of O.fusiformis but starts after gastrulation in the non-feeding larva with gradual metamorphosis of Capitella teleta and the directdeveloping embryo of Dimorphilus gyrociliatus. Accordingly, the embryos of O. fusiformis develop first into an enlarged anteriordomain that forms larval tissues and the adult head12. Notably, this also occurs in the so-called 'head larvae' of other bilaterians13-17, with which the O. fusiformis larva shows extensive transcriptomic similarities. Together, our findings suggest that the temporaldecoupling of head and trunk formation, as maximally observed in head larvae, facilitated larval evolution in Bilateria. Thisdiverges from prevailing scenarios that propose either co-option9,10 or innovation11 of gene regulatory programmes to explainlarva and adult origins.
