Strata In China Research Articles

Status constraint and lifestyle transition: a latent class analysis of health-related lifestyles among different social strata in China

The present study uses data from the Chinese General Social Survey (CGSS) to develop a multidimensional measure for the healthiness of Chinese citizens’ lifestyles. A latent class analysis reveals variety in Chinese people’s lifestyles. Three categories are identified: the healthy, the mixed, and the risky. People with higher socio-economic status (SES) are polarized between the healthy and the risky lifestyles, while those with lower SES tend to have a more mixed lifestyle. Generally speaking, Chinese people’s lifestyles are in constant change. Located in an advantageous social-structural position, members of the upper strata manage to choose the lifestyle beneficial to their health. At the same time, however, they are influenced by western lifestyles. Members of the lower strata are more constrained by social-structural status.

Distribution and characteristics of paleo-oil reservoirs in Cambrian Longwangmiao Formation in Anyue area of Sichuan Basin, China

The Anyue gas field is a giant marine gas field with the largest reserves of a single reservoir and the oldest strata in China. In this area, the proved gas reserves in the Cambrian Longwangmiao Formation are 4, 404×108 m3, which are believed to originate from crude oil cracking according to substantial evidences. The paleo-oil reservoirs in the area have been destroyed, and their fluid properties, scale and other characteristics are unclear, despite of the distribution preliminarily determined. In this paper, the paleo-oil reservoirs in the Cambrian Longwangmiao Formation in the Moxi–Gaoshiti area were analyzed thoroughly through conventional microscopic observation, together with quantitative grain fluorescence (QGF), total scanning fluorescence (TSF), and micro-laser Raman analysis. The study results indicate that the Longwangmiao Formation contains bitumen, which is mainly distributed in four types of pore space, i.e. vein-like fractures, dissolution pores, intergranular pores, and intercrystalline pores. The bitumen in vein-like fractures was formed mostly in relation to hydrocarbon migration, while the bitumen in dissolution pores, intergranular pores and intercrystalline pores was formed by in-situ cracking of petroleum, mostly as a result of thermal alteration. The QGF index suggests the existence of paleo-oil reservoirs in certain scale in the study area, and the high QGF-E intensity indicates the property of residual bitumen. The laser Raman spectroscopy reveals the maturity of the extensive solid bitumen in reservoir rocks. The well-cross section illustrates that the paleo-oil reservoirs are mainly layered, have experienced mostly in-situ cracking, and match with the present gas reservoirs.

Apparent-Depth Effects of the Dynamic Failure of Thick Hard Rock Strata on the Underlying Coal Mass During Underground Mining

Thick hard rock strata (THRS) are widely distributed among coal-bearing strata in China. The dynamic THRS failure may induce the coal-rock dynamic hazards during underground coal mining. In this study, the size, stress and energy characteristics of dynamic THRS failure were analyzed; the Yangliu coal mine, Huaibei coal basin, China, was taken as a case study. Then the apparent-depth effects of the dynamic THRS failure on the underlying coal mining were researched. The results revealed that the rock roof would be caved, fractured and deformed and even develop the bed separation during underlying coal mining. A large quantity of elastic energy is stored in the bent and compressed THRS, the amount and scope of the vertical stress concentration in front of the working face increases significantly before THRS breaking. THRS generally exhibit the square-form structure failure (SSF), after which the elastic and kinetic energy is attenuated in power form with the energy spreading distance. The shock force and energy effects of the dynamic THRS failure on the underlying coal mass were greater than those observed for the common lithological rock strata. Thus the mining coal mass below THRS bears similar mechanical conditions as the deeper coal mass and is of greater apparent depth, which is called the apparent-depth effects of the dynamic THRS failure. The apparent-depth effects of the dynamic THRS failure significantly influenced the coal-rock dynamic hazards according to in situ measurements of the mine earthquake energy, in situ stress, roof pressure and gas emission parameters. As a result, reasonable measures should be taken to avoid stress concentration and energy accumulation and to reduce the apparent depth of the mining-disturbed coal mass for preventing coal-rock dynamic hazards. The research results provide significant value for the control of coal-rock dynamic hazards below THRS.

Characteristics of gas generation from the pyrolysis of crude oil under the different geological conditions

In order to investigate the gas generation from the pyrolysis of the crude oil, the thermal pyrolysis simulation experiment of the crude oil under the different geological conditions are carried out by using high temperature and high pressure closed system. The cumulative amounts of gaseous hydrocarbons from the pyrolysis of crude oil are almost the same but the generating activation energy are different under the different media (limestone, mudstone, sandstone). The limestone has the greatest impact on the pyrolysis, followed by the mudstone and the sandstone. In addition, pressure and heating rate have an inhibitory effect on the pyrolysis of crude oil. The experimental results can provide an evidence for source judgment and resource evaluation of natural gas in marine strata in China.

Cretaceous integrative stratigraphy and timescale of China

Cretaceous strata are widely distributed across China and record a variety of depositional settings. The sedimentary facies consist primarily of terrestrial, marine and interbedded marine-terrestrial deposits, of which marine and interbedded facies are relatively limited. Based a thorough review of the subdivisions and correlations of Cretaceous strata in China, we provide an up-to-date integrated chronostratigraphy and geochronologic framework of the Cretaceous system and its deposits in China. Cretaceous marine and interbedded marine-terrestrial sediments occur in southern Tibet, Karakorum, the western Tarim Basin, eastern Heilongjiang and Taiwan. Among these, the Himalayan area has the most complete marine deposits, the foraminiferal and ammonite biozonation of which can be correlated directly to the international standard biozones. Terrestrial deposits in central and western China consist predominantly of red, lacustrine-fluvial, clastic deposits, whereas eastern China, a volcanically active zone, contains clastic rocks in association with intermediate to acidic igneous rocks and features the most complete stratigraphic successions in northern Hebei, western Liaoning and the Songliao Basin. Here, we synthesise multiple stratigraphic concepts and charts from southern Tibet, northern Hebei to western Liaoning and the Songliao Basin to produce a comprehensive chronostratigraphic chart. Marine and terrestrial deposits are integrated, and this aids in the establishment of a comprehensive Cretaceous chronostratigraphy and temporal framework of China. Further research into the Cretaceous of China will likely focus on terrestrial deposits and mutual authentication techniques (e.g., biostratigraphy, chronostratigraphy, magnetostratigraphy and cyclostratigraphy). This study provides a more reliable temporal framework both for studying Cretaceous geological events and exploring mineral resources in China.

A new dinosaur tracksite from the Lower Cretaceous Sanbukdong Formation of Gunsan City, South Korea

South Korea has become globally famous for various tetrapod footprints from Upper Cretaceous strata. Here we report the first Early Cretaceous “large” tracksite from the Sanbukdong Formation of an unnamed small basin in the west of Gunsan City, North Jeolla Province. The tracksite (720 m2) produced 425 tracks. Among them, eleven ornithopod and three theropod trackways (189 tracks) were measured and mapped in detail. Most of ornithopod tracks are large (32 cm–51 cm in length) and very similar to pes imprints of Caririchnium lotus from China in that the general track dimensions and large heel pad impressions are typically longer than wide. They are attributable to basal hadrosauroids based on their stratigraphic and palaeogeographic occurrence as well as skeletal evidence in Korea. Eleven ornithopod trackways show gregarious behaviour and two main directions of movements along a lake margin. One movement is that of a group that went back and forth along the lacustrine margin and the other movement showing dinosaurs that came to the lakeshore probably to drink water or any other purposes. One trackway consists of 39 consecutive tracks with the distance of 39 m, representing the longest Early Cretaceous ornithopod trackway ever found in Korea. Sanbukdong ornithopod tracks suggest that basal hadorsauroids had the same growth pattern as derived hadrosaurids such as a brief period where it was very rapid. They also support independently that the majority of Early Cretaceous basal hadrosauroids were smaller than Late Cretaceous hadrosaurids in body size. Two theropod trackways consist of large tracks (more than 40 cm in length) and closely resemble Irenesauripus glenrosensis from the Lower Cretaceous of Texas which was inferred to be of Acrocanthosaurus origin. It is reasonable that they are attributable to carcharodontosaurids because their skeletal materials were already reported from the Lower Cretaceous strata in China and Korea. This new tracksite indicates that large ornithopod and theropod dinosaurs lived in the Early Cretaceous in Korea and strengthens previous hypotheses of their existence based on only isolated teeth.

Quaternary integrative stratigraphy and timescale of China

Quaternary strata in China mainly comprise continental deposits in a variety of depositional settings. The continental Quaternary in temperate northern China consists mainly of eolian and fluvio-lacustrine deposits; that in subtropical southern China, mainly of vermiculated red soils, cave/fissure deposits, and fluvio-lacustrine deposits; and that in the alpine Tibetan Plateau, mainly of fluvio-lacustrine and piedmont deposits. The marine Quaternary in China consists of detrital deposits and biogenic reef deposits. The integration of biostratigraphy, magnetostratigraphy, climatostratigraphy and an astronomically calibrated chronology has led to the establishment of high-precision climatochronostratigraphic timescales for the detrital marine Quaternary in the South China Sea and the loess-paleosol sequence in the Chinese Loess Plateau. Extremely high-precision 230Th dating has provided a high-precision absolute age model for cave stalagmites over the past 640000 years as well as high-resolution oxygen isotope records representing orbital- to suborbital-scale climate changes. By combining magnetic stratigraphy and biostratigraphy, robust chronostratigraphic frameworks for non-eolian continental Quaternary deposits on the scale of Quaternary geomagnetic polarities have been established. The continental Pleistocene Series consists, from oldest to youngest, of the Nihewanian Stage of the Lower Pleistocene, the Zhoukoudianian Stage of the Middle Pleistocene, and the Salawusuan Stage of the Upper Pleistocene. Stages of the continental Holocene Series have not yet been established. This review summarizes recent developments in the Quaternary chronostratigraphy of representative Quaternary strata and associated faunas, and then proposes an integrative chronostratigraphic framework and a stratigraphic correlation scheme for Quaternary continental strata in China. In the near-future, it is hoped to establish not only a Chinese continental Quaternary climatochronostratigraphic chart on the scale of glacial-interglacial cycles but also a Quaternary integrative chronostratigraphic chart including both continental and marine strata in China.

Pore characteristics of lacustrine shale within the oil window in the Upper Triassic Yanchang Formation, southeastern Ordos Basin, China

Organic matter (OM)-rich shale in the Yanchang Formation is recognized as a promising hybrid shale oil/shale gas system in lacustrine strata in China. Being mainly in the oil window, both the type and distribution of the pores in the shale have been affected by several factors, including petroleum expulsion and retention, mineral and organic composition, and compaction. To obtain a better understanding of the factors controlling OM pore development, 10 core samples were selected with various OM content from the Chang 7 and Chang 9 members of the Yanchang Formation for pore characterization. The investigation combined microscopic observation, both of thin sections and ion milled surfaces of samples with low-pressure carbon dioxide and nitrogen adsorption and bulk porosity measurements, with the main emphasis being on OM-associated pores.The selected samples generally have relatively low total porosity, with the pores being poorly connected. Most pore types found in marine shales were present. The size of porous OM is usually small, mostly measuring several hundreds of nanometers to a few micrometers, which suggest a general compaction effect on pore development. The pore development is related to different petroleum expulsion processes. Shale with very porous OM was a very important feature. The OM coexisting with fluorescent lipitinites was present in a cross-linked nanofiber structure, possibly related to altered extracellular polymeric substances (EPS) by compaction and maturation. Various OM types that varied in both size and shape did not contain any visible pores (e.g. woody relics, migrated solid bitumen and OM laminae in close association with clay minerals). Unusually low meso- and macropore volume in the sample with the highest total organic carbon (TOC) content was confirmed by the predominance of OM laminae without visible pores; however, abundant micropores were indicated by CO2 adsorption analysis. Meso- and macropores in this sample had probably not developed due to a significant compaction effect. Due to the small numbers of studied samples, these OM pore characteristics need to be viewed with caution.

Characteristics of gaseous hydrocarbons generated from asphaltene pyrolysis and the geochemical significance

ABSTRACTIn order to study the mechanism of gas generation from the asphaltene, the thermal pyrolysis simulation experiment of the asphaltene is carried out by using high temperature and high pressure closed system. During asphaltene pyrolysis, the amount of methane is constantly increased but those of ethane, propane, and butane + pentane are all first increased and then decreased and eventually go to zero with the increase of the experiment temperature. And the dynamic parameters of gaseous hydrocarbon generation can be used to analyze the dynamic procedure of the asphaltene pyrolysis at the geological scale. The experimental results can perfect the theory of the origin of natural gas and provide an evidence for source judgment and resource evaluation of natural gas in marine strata in China.

Social Stratification and Studying Overseas: Empirical Evidence from Middle Schools in Beijing

Through analyzing original survey data from 1012 ninth graders at 9 middle schools collected in Beijing in 2015 and adopting the frameworks of social stratification and Effectively Maintained Inequality, this study examines the differential in the choice of and access to such educational resources as studying overseas among different social strata in China. Particular attention is paid to students from those groups which are at an advantage in building networks and mobilizing social resources, namely high-ranking officials, wealthy business owners, and white-collar professionals. By analyzing how different social strata differ in their willingness and plan to study overseas, this empirical study has shown that studying overseas, which is considered an option for pursuing high-quality educational resources, has proven to be such a tool for advantaged social classes to maintain their status and for disadvantaged social classes to climb up the social ladder.

Forming Mechanism Analysis of the Abnormally High δ34S Baryte Deposits: A Case Study from the Zhenning–Ziyun Large Devonian Baryte Deposits, Guizhou Province, China

ABSTRACTStratiform baryte deposits are widespread in Cambrian and Devonian strata in China and around the world. In this article, the authors studied the sulfur isotopic features and forming mechanism of the stratiform baryte deposits occurring within the Upper Devonian cherts of the Zhenning-Ziyun county, Guizhou province, located in the Southwestern margin of the Yangtze Platform. The sulfur isotopic data from 18 baryte ore samples of the Leji section of Zhenning county are presented herein with values that range from +41.9‰ to +68.4‰ (AVG = +59.9‰). The δ34S values of the baryte ore from the Mohao section of Ziyun county are stable and show a narrow range from +41.3‰ to +47.0‰ (AVG = +44.0‰). In the Luocheng section of Ziyun county, the δ34S values of the baryte ore vary from +27.6‰ to +36.4‰ (AVG = +32.7‰). The δ34S values of all samples are higher than those of the coeval seawater sulfates (+25‰). The scanning electron microscope analysis indicates that spherical, dumbbell-shaped, clavate bacterial and bacteria-like fossils were observed, as well as the irregular schistose and framboid forms of Fe oxides that occur around the surfaces of baryte grains and inter-grains. Fe oxides take irregular schistose and framboid forms. These findings imply the significant concentration of heavy sulfur related to the seawater sulfates with the action of bacterial sulfate reduction in a closed basin. In addition, the trend of the δ34S value of baryte ores is gradually decreasing from the Leji to Mohao and Luocheng sections, which suggests that Leji area is located in the deepwater area of the restricted rift basin, and in a more closed depositional environment.

Status of Stratigraphy Research in China

AbstractScientific research and productive practice for earth history are inseparable from the accurate stratigraphic framework and time framework. Establishing the globally unified, precise and reliable chronostratigraphic series and geological time series is the major goal of the International Commission on Stratigraphy (ICS). Under the leadership of the ICS, the countries around the world have carried out research on the Global Standard Stratotype‐section and Points (GSSPs) for the boundaries of chronostratigraphic systems. In the current International Chronostratigraphic Chart (ICC), 65 GSSPs have been erected in the Phanerozoic Eonothem, and one has yet been erected in the Precambrian Eonothem. Based on the progress of research on stratigraphy especially that from its subcommissions, the ICS is constantly revising the ICC, and will publish a new International Stratigraphic Guide in 2020. After continual efforts and broad international cooperation of Chinese stratigraphers, 10 GSSPs within the Phanerozoic Eonothem have been approved and ratified to erect in China by the ICS and IUGS. To establish the standards for stratigraphic division and correlation of China, with the support from the Ministry of Science and Technology, the National Natural Science Foundation of China and the China Geological Survey, Chinese stratigraphers have carried out research on the establishment of Stages in China. A total of 102 stages have been defined in the “Regional Chronostratigraphic Chart of China (geologic time)”, in which 59 stages were studied in depth. In 2014, the “Stratigraphic Chart of China” was compiled, with the essential contents as follows: the correlation between international chronostratigraphy and regional chronostratigraphy of China (geologic time), the distributive status of lithostratigraphy, the characteristics of geological ages, the biostratigraphic sequence, the magnetostratigraphy, the geological events and eustatic sea‐level change during every geological stage. The “Stratigraphical Guide of China and its Explanation (2014)” was also published. Chinese stratigraphers have paid much attention to stratigraphic research in south China, northeast China, north China and northwest China and they have made great achievements in special research on stratigraphy, based on the 1:1000000, 1:250000, 1:200000 and 1:50000 regional geological survey projects. Manifold new stratigraphic units were discovered and established by the regional geological surveys, which are helpful to improve the regional chronostratigraphic series of China. On the strength of the investigation in coastal and offshore areas, the status of marine strata in China has been expounded. According to the developing situation of international stratigraphy and the characteristics of Chinese stratigraphic work, the contrast relation between regional stratigraphic units of China and GSSPs will be established in the future, which will improve the application value of GSSPs and the standard of regional stratigraphic division and correlation. In addition, the study of stratigraphy of the Precambrian, terrestrial basins and erogenic belts will be strengthened, the Stratigraphic Chart of China will be improved, the typical stratigraphic sections in China will be protected and the applied study of stratigraphy in the fields of oil and gas, solid minerals, etc. will be promoted. On the ground of these actions, stratigraphic research will continue to play a great role in the social and economic development of China.

Valuable elements in Chinese coals: a review

ABSTRACTChina is, and in the coming decades should continue to be, the largest producer and user of coal in the world. The high volume of coal usage in China has focused attention not only on the toxic trace elements that may be released from coal combustion but also on the valuable elements that may occur in the coal and associated ash. Valuable elements in several coals (or coal ashes) and some coal-bearing strata in China (e.g. Ge, Ga, U, rare earth elements and Y, Nb, Zr, Se, V, Re, Au, and Ag, as well as the base metal Al) occur at concentrations comparable to or even higher than those in conventional economic deposits. Several factors are responsible for these elevated concentrations: (1) injection of exfiltrational solutions during peat accumulation or as part of later epigenetic activity; (2) injection of infiltrational epigenetic solutions; (3) introduction of syngenetic alkali volcanic ashes into the peat-forming environment or into associated non-coal-forming terrestrial environments; (4) input of terrigenous materials into the coal-forming environment; (5) leaching of non-coal partings by groundwater/hydrothermal solutions; and (6) mixed processes involving both hydrothermal solutions and volcanic ash. The valuable elements in Chinese coals may be associated with either the organic matter or mineral matter, or have a mixed organic- and inorganic-affinity. For example, the Ge and U in coal-hosted ore deposits dominantly occur in the organic matter, with only traces of U-bearing minerals being present; gallium mainly occurs in boehmite and kaolinite, and to a lesser extent, in the organic matter. Rare earth elements and Y occur as carbonate-minerals (e.g. florencite, parisite), phosphate-minerals (e.g. rhabdophane, silico-rhabdophane, and xenotime), and in part are associated with the organic matter. Some metals (e.g. Ge, Al, Ga) have been successfully extracted at an industrial scale from Chinese coals, and others have significant potential for such extraction. Major challenges remaining for coal scientists include the development of economic extraction methods from coal ash, and the control of toxic elements released during the metal extraction process to protect human health and to avoid environmental pollution.

Multiple proxies indicating methane seepage as the origin of Devonian large barite deposit in Zhenning-Ziyun, Guizhou, SW China

Bedded barite deposits are found in Cambrian and Devonian strata in China. In this paper, we report the occurrence of Late Paleozoic methane seeps from bedded barite in one of the largest barite deposits in China. The ore bodies are stratiform and lenticular in shape and are hosted within Upper Devonian cherts. The barite deposits usually have laminar, banded, fragmental, massive and rosette textures, and radial and spheroidal structures were observed in the barite ores. Nodular limestones are associated with the barite deposits; they consist of clotted micrites and framboidal pyrites. The internal structure of framboidal pyrite is simple, in which the sun-flower structure has been observed, similar to modern seep carbonates. The δ13CV-PDB values range from −8.82‰ to −10.27‰, and δ18OV-PDB ranges from −8.10‰ to −8.20‰ in Xiyahe and from +0.03‰ to −3.31‰ in Luocheng. The 13C depletion suggests that these carbonates formed in a methane seep through the anaerobic oxidation of methane (AOM). This evidence lends strong support to the interpretation that methane hydrate contributed to the barite deposition. In addition, the δ13CV-PDB values decrease gradually from Xiyahe to Luocheng, which indicates the gradually weakening strength of the methane seep activities. The δ30SiNBS-28 values of the cherts range from −0.3‰ to +0.5‰, except for two samples (LJ-24: δ30SiNBS-28 values=+0.9‰; ZL18: δ30SiNBS-28 values=+1.1‰). The lowest δ30SiNBS-28 values reflect silicon derived from hydrothermal fluids ascribed to intense tectonic activity, which consequently caused the rapid maturity of hydrocarbons. The 87Sr/86Sr values (87Sr/86Sr=0.70863–0.70898, avg. 0.70877; n=11) of barite are higher than the average value of contemporary seawater, showing that hydrothermal processes played a minor role in barite mineralization.

Mineral Composition and Brittleness Analysis of Organic-Rich Lower Paleozoic Shale in South Sichuan and North Yunnan Areas of China

Organic-rich Lower Paleozoic Qiongzhusi, Wufneg, and Longmaxi formations in South Sichuan and North Yunnan areas are the main gas prospecting strata in China. XRD analysis is used to determine the mineral composition and brittleness indexes of three shale suites in these areas. These parameters are important for evaluating shale gas resources, analyzing reservoir-forming mechanisms, and planning prospecting. The investigation results indicate that the three shale suites have a mean quartz content of more than 27% and a mean clay mineral content of less than 37.27%. Their sedimentary environment is euxinic. They passed through a telodiagenetic phase. The mean relative brittleness index of the samples from Qiongzhusi, Wufneg, and Longmaxi formations are 69.54, 67.33, and 60.44%, respectively. Such high relative brittleness indexes imply that the studied shale suites have good fracturability.

Review of the Cervical Cancer Burden and Population-Based Cervical Cancer Screening in China.

Cervical cancer continues to be a serious public health problem in the developing world, including China. Because of its large population with geographical and socioeconomic inequities, China has a high burden of cervical cancer and important disparities among different regions. In this review, we first present an overview of the cervical cancer incidence and mortality over time, and focus on diversity and disparity in access to care for various subpopulations across geographical regions and socioeconomic strata in China. Then, we describe population-based cervical cancer screening in China, and in particular implementation of the National Cervical Cancer Screening Program in Rural Areas (NACCSPRA) and the challenges that this program faces. These include low screening coverage, shortage of qualified health care personnel and limited funds. To improve prevention of cervical cancer and obtain better cancer outcomes, the Chinese government needs to urgently consider the following key factors: reducing disparities in health care access, collecting accurate and broadly representative data in cancer registries, expanding target population size and increasing allocation of government funding for training of personnel, improving health education for women, enhancing quality control of screening services and improving a system to increase follow up for women with positive results.

10 year trends in urban–rural disparities in treatments and outcomes after ST-elevation myocardial infarction in China: insights from the China PEACE-Retrospective Acute Myocardial Infarction Study

BackgroundIn response to the epidemic transition, like in many other low-income and middle-income countries, China has been building capacities and improving access to health care in its health-care reform, with the budget favouring rural areas. Yet the trend in disparities between urban and rural areas in treatments and outcomes of ST-segment elevation myocardial infarction (STEMI) have not been well characterised. The aim of this study was to illustrate whether the quality of care for STEMI differed between urban and rural hospitals, and how it changed from 2001 to 2011. MethodsUsing a two-stage random sampling design including two urban and three rural strata in China, we created a nationally representative sample of patients with STEMI in China in 2001, 2006, and 2011. We collected clinical information through centralised medical chart abstraction and did surveys to determine hospital characteristics. We compared a composite outcome as in-hospital mortality or withdrawal from treatment due to a terminal status at discharge. The central ethics committee at the China National Center for Cardiovascular Diseases approved the study, with a waiver of patients' written consent. This study is registered with ClinicalTrials.gov, number NCT01624883. FindingsWe identified 8330 cases of STEMI in 63 urban hospitals and 5485 cases of STEMI in 99 rural hospitals. The admission rate for STEMI remained three-times higher in urban areas than in rural areas (7·4 vs 2·0 per 100 000 population in 2001; 28·1 vs 8·7 per 100 000 population in 2011; both p<0·0001). Despite the difference in 2001, rural–urban differences were attenuated in 2011 for reperfusion therapy (57% vs 54%), use of ACEI/ARB (68% vs 66%), whereas use of beta-blockers was greater in rural areas than in urban areas in 2011 (60% vs 56%). The risk-adjusted rate of in-hospital death or withdrawal from treatment did not differ between patients in rural and urban hospitals in all 3 years, with an adjusted odds ratio of 0·88 (95% CI 0·61–1·29; p=0·5) in 2001, 1·01 (0·79–1·29; p=0·9) in 2006, and 1·07 (0·84–1·36; p=0·6) in 2011. Similar results were observed for in-hospital complications. InterpretationIn the medical records abstraction, definitions of certain clinical conditions and completeness of documentation might differ between urban and rural hospitals. Nevertheless, the stratified random sample in our study provided a unique opportunity to extend the understanding on urban–rural differences in STEMI care and the temporal trends in the largest developing country. Despite enormous opportunities for improvement in both urban and rural areas, urban hospitals with more affluent resources produced no extra benefit for patient. Capacity building alone, as a partial solution, is inadequate to reduce the burden. Accountable measures and improvement initiatives for quality are needed to ensure that the health-care sector achieves its potential values. FundingResearch Special Fund for Public Welfare Industry of Health (201202025) from National Health and Family Planning Commission of China, the National Key Technology R&D Program (2013BAI09B01) from the Ministry of Science and Technology of China, and grant 20131100501 from State Administration of Foreign Experts Affairs of China. HMK is supported by grant U01 HL105270-05 (Center for Cardiovascular Outcomes Research at Yale University) from the National Heart, Lung, and Blood Institute. The funders had no role in the conduct of the study; in the collection, management, analysis, and interpretation of the data; or in the preparation or approval of the abstract.

Innovation and prospect of geophysical technology in the exploration of deep oil and gas

Abstract The global situation of distribution, reserves and production of deep oil and gas are examined systematically, the progress and exploration achievement of onshore China deep geophysical technology are summarized, and the challenges and developing direction of deep geophysical technology are pointed out. Aiming at the exploration of deep onshore strata in China, the article analyzes the key geophysical problems, such as low signal-to-noise ratio, low resolution, low imaging accuracy and low amplitude-preservation, in the exploration of deep clastic, carbonate, and volcanic reservoirs, and presents the corresponding technical countermeasures such as wide-line large-array 2-D acquisition, wide-azimuth and high-density 3-D acquisition, anisotropic pre-stack depth migration (PSDM), reverse-time migration (RTM), complex structure modeling, and quantitative reservoir prediction. The analysis from two aspects, imaging of deep complicated structures and prediction of deep complicated reservoirs, shows that wide-frequency, amplitude-preservation, high-accuracy and information integration are the challenges to and key issues in the geophysical technology. It is pointed out that wide-frequency seismic acquisition, rock physical modeling of complex reservoirs, high-accuracy prestack amplitude-preservation imaging, comprehensive evaluation of complex reservoirs, non-seismic techniques, and drilling steering with seismic data are the key geophysical techniques needed to be developed in the future.

An Analysis of Strata Differences in Higher Education Opportunities (1982–2010)—Based on an Empirical Survey of 16 Chinese Universities

:Empirical study results show that in the past 30 years, after slightly expanding in the early 1990s, the differences in overall higher education opportunities among the children of all strata of China have continually shrunk. Regarding different types of higher education opportunities, the differences in access to key universities first expanded, then shrunk; the differences in going to ordinary baccalaureate higher education institutions (HEIs) and associates HEIs have continually shrunk since 1982. To a certain degree, the study results verify the MMI and MEI theories. Various intervention measures should be used in the future to increase the quality of ordinary baccalaureate HEIs and associates HEIs, and further equalize the access to higher education for children from all social strata.

Geochronology and geochemistry of tuff beds from the Shicaohe Formation of Shennongjia Group and tectonic evolution in the northern Yangtze Block, South China

Meso- to Neoproterozoic magmatic events are widespread in the Yangtze Block. The geochronology and tectonic significance of the Shennongjia Group in the Yangtze Block are still highly controversial. An integrated geochronology and geochemistry approach provides new insights into the geochronological framework, tectonic setting, magmatic events, and basin evolution of the northern Yangtze Block. Our new precise sensitive high-resolution ion microprobe U–Pb data indicate a deposition age of 1180 ± 15 Ma for the Shicaohe Formation subalkaline basaltic tuff that is geochemically similar to modern intracontinental rift volcanic rocks. The integration of available geochemical data together with our new U–Pb ages indicates the Shicaohe Formation subalkaline basaltic tuff formed ca. 1180 in a continental rift-related setting on a passive continental margin. The Shennongjia Group is topped by the Zhengjiaya Formation volcanic sequence, indicating arc-related igneous events at 1103 Ma. The transition of the late Mesoproterozoic tectonic regime from intracontinental extension to convergence occurred between ca. 1180 and 1103 Ma in the northern Yangtze Block. Tectonic evolution in the Neoproterozoic led to accretion along the northern margin of the Yangtze Block. These results provide geochronological evidence, which is of utmost importance for reconfiguration of the chronostratigraphic framework and for promoting research on Mesoproterozoic strata in China, thereby increasing understanding of magmatic events and basin evolutionary history in the northern Yangtze Block.