In order to study the restoration of road landscape space,subjective evaluation method was adopted to visually evaluate different road spaces in Tianjin University with college students as the research objects.Using r...In order to study the restoration of road landscape space,subjective evaluation method was adopted to visually evaluate different road spaces in Tianjin University with college students as the research objects.Using random block design,9 plots were quantitatively studied by Perceived Restorativeness Scale(PRS)from four dimensions:alienation,compatibility,richness and attractiveness.The results show that gray space has the worst restorative effect in the dimension of alienation,and can not bring people the feeling of being away from daily trivialities;in terms of compatibility dimension,green and blue spaces have better restorative effects;richness dimension has no obvious influence on the restoration of plots;in terms of attraction dimension,blue space has strong restorative ability and can easily attract people’s attention,while gray space has low attraction.There are differences in environmental restoration among different types of road space,and gray space,blue space and green space show weak,strong,and relatively stable restorative effects,respectively.展开更多
The contamination levels and distribution characters of heavy metals in coastal waters and sediments from Tianjin Bohai Bay,China were examined.Pb and Zn were found as the main heavy metal pollutants in the coastal wa...The contamination levels and distribution characters of heavy metals in coastal waters and sediments from Tianjin Bohai Bay,China were examined.Pb and Zn were found as the main heavy metal pollutants in the coastal waters of the bay.High levels of Pb and Zn appeared especially near the estuary,indicating that river discharge was the main pollution source.Moreover,atmospheric deposition resulted in Pb contamination in the middle of the embayment.Analysis of data for the period 1987-2004 indicated that Pb pol...展开更多
In this study sediment samples were collected from 13 sites of Haihe River in Tianjin City, China, sixteen of priority polycyclic aromatic hydrocarbons (PAHs) listed in USEPA were analyzed by means of GC-MS. The tot...In this study sediment samples were collected from 13 sites of Haihe River in Tianjin City, China, sixteen of priority polycyclic aromatic hydrocarbons (PAHs) listed in USEPA were analyzed by means of GC-MS. The total concentrations of PAH ranged from 774.81 to 255371.91 ng/g dw, and two to four rings of PAHs were dominant in sediment samples. Molecular ratios, such as phenanthrene/anthracene, fluoranthene/pyrene and low-molecular-weight PAH/high-molecular-weight PAH, were used to study the possible sources of pollution. It indicated a mixed pattern of parolytic and petrogenic inputs of PAHs in sediments in Haihe River. The petrogenic PAHs may be mainly derived from the leakage of refined products, e.g., gasoline, diesel fuel and fuel oil vehicle traffics or gas stations from urban area. The pyrolytic PAHs might be from the discharge of industrial wastewater and the emission of atmospheric particles from petrochemical factories. In addition, the levels of PAHs in the urban and industrial areas are far beyond the values reported from other rivers and marine systems reported. This situation may be due to polluted discharging from some petrochemical industrial manufactories and worse traffic conditions in Tianjin.展开更多
The contents and distribution of 20 polycyclic aromatic hydrocarbons (PAHs) and heterocyclic aromatic hydrocarbons (HAHs) were investigated in 16 soil profiles of Beijing and Tianjin region. Transport of high mole...The contents and distribution of 20 polycyclic aromatic hydrocarbons (PAHs) and heterocyclic aromatic hydrocarbons (HAHs) were investigated in 16 soil profiles of Beijing and Tianjin region. Transport of high molecular weight PAHs (HMWPAHs) and the correlation between total organic carbon (TOC) and their concentrations were also discussed. The results indicated that highly contaminated sites were located at urban or wastewater irrigation areas and pollutants mainly accumulated in topsoil (〈 40 cm), with a sharp content decrease at the vertical boundary of 30-40 cm. Total PAHs/HAHs concentrations in soils from Tianjin were markedly greater than those from Beijing. Even the contents at bottoms of soil profiles in Tianjin were higher than those in topsoils of Beijing soil profile. HMWPAHs dominated the PAH profiles, exhibiting a uniform distribution of pyrogenic origin between topsoils and deep layers. Furthermore, the percentages of HMWPAHs remained relative constant with the depth of soil profiles, which were consistent with the distribution of particulate matter-associated PAHs in the local atmospheric environments. Therefore, HMWPAHs transport with particulates might be the predominant source found in soil profiles.展开更多
Taken fractal dimension, compact ratio, urban centroid and urban principal axis as the urban spatial characteristic indices, Tianjin city's urban area is investigated in the last 26 years in a quantitative perspectiv...Taken fractal dimension, compact ratio, urban centroid and urban principal axis as the urban spatial characteristic indices, Tianjin city's urban area is investigated in the last 26 years in a quantitative perspective, and its traits and changes during different periods are also analyzed. It is clear that these indices can not only scientifically and explicitly assess the urban morphology, urban direction and its changes and trends, but also uncover long-term effects of economy and urban planning on urban morphology.展开更多
Both the macroscopic feature and the sequence-stratigraphic position of the molar-tooth structure developed in the third member of the Gaoyuzhuang (高于庄) Formation at the Jixian (蓟县) Section in Tianjin (天津...Both the macroscopic feature and the sequence-stratigraphic position of the molar-tooth structure developed in the third member of the Gaoyuzhuang (高于庄) Formation at the Jixian (蓟县) Section in Tianjin (天津) can provide some useful information about its origin and can reveal some problems to be further researched in the future. The Mesoproterozoic Gaoyuzhuang Formation is a set of 1 600 m thick carbonate strata. This formation can be divided into four members. The first member is mainly made up of stromatolitic dolomites; the second is marked by a set of manganese dolomites; the third is mainly composed of lamina limestones with the development of molar-tooth strcutures; the fourth is a set of stromatolitic-lithoherm dolomites. According to lithofacies and its succession, several types of meter-scale cycles can be discerned in the Gaoyuzhuang Formation: the L-M type, the subtidal type and the peritidal type. There is a regularly vertical stacking pattern for meter-scale cycles in the third-order sequence. Therefore, the Mesoproterozoic Gaoyuzhuang Formation can be divided into 13 third-order sequences (SQ1 to SQ13 ) and can further be grouped into 4 second-order sequences. The third member is marked by lamina limestones and can be grouped into three third-order sequences (SQ9 to SQ11 ). The molar-tooth structure is developed in the middle part of the third sequence, i.e. SQH , in the third member. Several features of this kind of molar-tooth structure reflect some features of carbonate sedimentation in the Precambrian, such as the particular configuration, abundant organic matter, and easy silication. Stromatolites are chiefly formed in a shallow tidal-flat environment; lamina are mainly formed in the shallow ramp and molar-tooth structures are mainly generated in a relatively more deep-water environment from the middle to the deep ramp. Therefore, similar to stromatolite and lamina, the molartooth structure might also be a kind of bio-sedimentation structure. This suggestion is based on macroscopic observation and the sedimentary-facies analysis of the molar-tooth structures from the sequencestratigraphic position. These features of Precambrian sedimentation also reveal the problem of Precambrian carbonate sedimentation. With more detailed study, a more practical solution for these problems may be obtained in the future.展开更多
Molar-tooth(MT) structure is an enigmatic sedimentary structure consisting of variously-shaped cracks and voids filled with a characteristically uniform,equant calcite microspar.It is globally distributed but temporal...Molar-tooth(MT) structure is an enigmatic sedimentary structure consisting of variously-shaped cracks and voids filled with a characteristically uniform,equant calcite microspar.It is globally distributed but temporally restricted to rocks from Neoarchean to Neoproterozoic age.The origin of MT structures has been debated for more than a century and the topic continues to be highly contentious.Some features of MT structure occurring in micritic limestones of the Mesoproterozoic Gaoyuzhuang Formation(ca.1500 Ma to ca.1400 Ma),Jixian section,Tianjin City,North China show that:1) there is a definite interface or lining,rich in organic material and pyrite,between the MT crack-filling calcite microspar and the micritic host rock,which is also rich in organic matter;2) the micritic host rocks are notable for the absence of stromatolites and microbial laminites;3) distinctive conglomeratic lag deposits made up of intraclasts of MT microspar result from storm reworking of the MT structures;4) the MT structure is associated with possible algal megafossils such as Chuaria;5) the MT microspar is made up of the larger calcite crystal and the MT crack is marked by the diversity of configurations;6) both the TOC content and the carbon-isotopic value(δ^(13)C_(PDB)) among the host rock, the MT microspar and the possible algae fossil are obviously different.For the forming mechanism of the Gaoyuzhuang MT structure,these features can still indicate that:A) the MT microspar was formed by rapid precipitation and lithification;B) the MT microspar precipitated directly within the cracks; C) the decomposition of organic matter within the host micrite might be the chief mechanism producing gas bubbles;D) microscale gas-sediment interaction led to the generation of the MT cracks and the precipitation of microspar therein;E) the MT cracks might represent the track of migration and expansion of gas bubbles,and that the recrystallization of host micrites cannot be eliminated during forming process of the MT microspar;F) the MT structure is occurred in early diagenetic period;and G) the formation of MT microspars is a complex diagenetic process.Therefore,model of the microbially-induced gas-bubble expansion and migration is the best interpretation for the formation of the MT structure.Effectively,MT structures are a type of sedimentary structure that is formed in the early diagenetic period and is related to microbial activities and organic matter degradation.展开更多
The epidemiologic characteristics of 631 infant pertussis cases 〈 12 months, which accounted for 57.42% of the total cases, were analyzed by descriptive epidemiology in Tianjin, between 2010 and 2015. The incidence o...The epidemiologic characteristics of 631 infant pertussis cases 〈 12 months, which accounted for 57.42% of the total cases, were analyzed by descriptive epidemiology in Tianjin, between 2010 and 2015. The incidence of infants was 104.66/100,000, which was 118 times higher than in other age groups (P 〈 0.001). The primary type of pertussis simultaneously presented in households was adult-to-infant (70.51%). The parents were identified as the source of infection in 80.18% of cases for infants. The positive rate of placental antibody transfer was 31.06% and 3.13% for 3-month-old infants. Infants presented the highest age-specific pertussis incidence. The most important reason was parents were the important sources of infection, and secondly the lower level of antibodies in neonates and the rapid waning of maternal antibody titer.展开更多
High concentrations of air pollutants such as total suspended particulates(TSP) and sulfur dioxide(SO_2) have serious impacts on nearby populations. In this paper, a survey of rural Tianjin residents' willingness-...High concentrations of air pollutants such as total suspended particulates(TSP) and sulfur dioxide(SO_2) have serious impacts on nearby populations. In this paper, a survey of rural Tianjin residents' willingness-to-pay for health improvement was reported on, and the MBDC(multiple bounded discrete choice) model was adopted to study the respondents' willingness-to-pay to prevent respiratory illnesses. The results showed that the willingness-to-pay for health improvement was affected by respondents' health condition, work situation and environmental awareness, but not by personal habits, such as smoking. If person's willingness-to-pay to avoid respiratory diseases can be considered equal to the cost to personal health caused by air pollution, the total cost will reach 538×10 6 RMB Yuan(RMB, equal to 65 million USD) per year.展开更多
In this study, regional persistent haze events(RPHEs) in the Beijing–Tianjin–Hebei(BTH) region were identified based on the Objective Identification Technique for Regional Extreme Events for the period 1980–201...In this study, regional persistent haze events(RPHEs) in the Beijing–Tianjin–Hebei(BTH) region were identified based on the Objective Identification Technique for Regional Extreme Events for the period 1980–2013. The formation mechanisms of the severe RPHEs were investigated with focus on the atmospheric circulation and dynamic mechanisms. Results indicated that:(1) 49 RPHEs occurred during the past 34 years.(2) The severe RPHEs could be categorized into two types according to the large-scale circulation, i.e. the zonal westerly airflow(ZWA) type and the high-pressure ridge(HPR) type. When the ZWA-type RPHEs occurred, the BTH region was controlled by near zonal westerly airflow in the mid–upper troposphere.Southwesterly winds prevailed in the lower troposphere, and near-surface wind speeds were only 1–2 ms^-1. Warm and humid air originating from the northwestern Pacific was transported into the region, where the relative humidity was 70% to 80%, creating favorable moisture conditions. When the HPR-type RPHEs appeared, northwesterly airflow in the mid–upper troposphere controlled the region. Westerly winds prevailed in the lower troposphere and the moisture conditions were relatively weak.(3) Descending motion in the mid-lower troposphere caused by the above two circulation types provided a crucial dynamic mechanism for the formation of the two types of RPHEs. The descending motion contributed to a reduction in the height of the planetary boundary layer(PBL), which generated an inversion in the lower troposphere. This inversion trapped the abundant pollution and moisture in the lower PBL, leading to high concentrations of pollutants.展开更多
Tianjin is one of the inland cities with the most severe cases of subsidence hazard in China.The majority of the existing studies have mainly focused on Beijing-Tianjin-Hebei,and little attention has been given to Tia...Tianjin is one of the inland cities with the most severe cases of subsidence hazard in China.The majority of the existing studies have mainly focused on Beijing-Tianjin-Hebei,and little attention has been given to Tianjin.In addition,these existing studies are short-term investigations,lacking long-term monitoring of surface subsidence.In the present study,we use the Small Baseline Subset Interferometric Synthetic Aperture Radar(SBAS-InSAR)technique to monitor the subsidence process in Tianjin between 2015 and 2020 and reveal its spatial and temporal variation.We divided the 44-view Sentinel-1A image data into three periods to avoid the effect of temporal and spatial decoherence by extracting the surface deformation field in Tianjin.We finally verified the accuracy and reliability of the inversion results using second-order leveling data.Results showed that the correlation coefficient r between the two reached 0.89,and the root mean square error was 4.84 mm/y.Obvious subsidence funnels exist in Tianjin,mainly in the towns of Wangqingtuo and Shengfang.These subsidence funnels have a subsidence deformation rate of-136.2 mm/y and a maximum cumulative settlement of-346.3 mm within the study period.The subsidence area tends to extend to the southwest.The analysis of annual rainfall,groundwater resource extraction,spatial location distribution of industrial areas combined with SBAS-InSAR inversion results indicates that overextraction of groundwater resources is the main cause of land subsidence in the area.Therefore,strict control of groundwater extraction is the main approach to mitigate land subsidence effectively.展开更多
The current situation of medical staff's awareness about high alert medication was investigated in order to promote safe medication and standardized management of the high alert medication in China. Twenty questions ...The current situation of medical staff's awareness about high alert medication was investigated in order to promote safe medication and standardized management of the high alert medication in China. Twenty questions were designed concerning elementary knowledge of high alert medications, storage management, medication issues and risks. In order to understand the knowledge level and education status of high alert medication, a convenient survey was conducted among 300 medical staffs in Tianjin. Medical staff's average score of high alert medication knowledge was 12.43±0.27, and the average scores of elementary knowledge of high alert medication, storage management, medication issues and risks were 3.38±0.11, 2.46±0.14, 3.17±0.11 and 3.41±0.12 respectively. Occupation(F=4.86, P=0.003), education background(F=5.57, P=0.019) and professional titles(F=13.44, P≤0.001) contributed to the high alert medications knowledge scores. Currently, the most important channel to obtain high alert medication knowledge was hospital files or administrative rules, and clinical pharmacist seminars were the most popular education form. It was suggested that the high alert medication knowledge level of the medical staff needs to increase, and it might benefit from targeted, systematic and diverse training to the medical staff working in the different circulation nodes of the medications. Further research to develop and validate the instrument is needed.展开更多
Taking Tianjin as an example, this paper proposed a methodology and process for evaluating near-fault strong ground motions from future earthquakes to mitigate earthquake damage for the metropolitan area and important...Taking Tianjin as an example, this paper proposed a methodology and process for evaluating near-fault strong ground motions from future earthquakes to mitigate earthquake damage for the metropolitan area and important engineering structures. The result of strong ground motion was predicted for Tianjin main faults by the hybrid method which mainly con- sists of 3D finite difference method and stochastic Green's function. Simulation is performed for 3D structures of Tianjin re- gion and characterized asperity models. The characterized asperity model describing source heterogeneity is introduced fol- lowing the fault information from the project of Tianjin Active Faults and Seismic Hazard Assessment. We simulated the worst case that two earthquakes separately occur. The results indicate that the fault position, rupture process and the sedi- mentary deposits of the basin significantly affect amplification of the simulated ground motion. Our results also demonstrate the possibility of practical simulating wave propagation including basin induced surface waves in broad frequency-band, for seismic hazard analysis near the fault from future earthquakes in urbanized areas.展开更多
Launched in 2002, the Beiing–Tianjin Sand Source Control Project (BTSSCP) is an ecological restoration project intended to prevent desertification in China. Evidence from multiple sources has confirmed increases in v...Launched in 2002, the Beiing–Tianjin Sand Source Control Project (BTSSCP) is an ecological restoration project intended to prevent desertification in China. Evidence from multiple sources has confirmed increases in vegetation growth in the BTSSCP region since the initiation of this project. Precipitation and essential climate variable-soil moisture (ECV-SM) conditions are typically considered to be the main drivers of vegetation growth in this region. Although many studies have investigated the inter-annual variations of vegetation growth, few concerns have been focused on the annual and seasonal variations of vegetation growth and their climatic drivers, which are crucial for understanding the relationships among the climate, vegetation, and human activities at the regional scale. Based on the normalized difference vegetation index (NDVI) derived from MODIS and the corresponding climatic data, we explored the responses of vegetation growth to climatic factors at annual and seasonal scales in the BTSSCP region during the period 2000–2014. Over the study region as a whole, NDVI generally increased from 2000 to 2014, at a rate of 0.002/a. Vegetation growth is stimulated mainly by the elevated temperature in spring, whereas precipitation is the leading driver of summer greening. In autumn, positive effects of both temperature and precipitation on vegetation growth were observed. The warming in spring promotes vegetation growth but reduces ECV-SM. Summer greening has a strong cooling effect on land surface temperature. These results indicate that the ecological and environmental consequences of ecological restoration projects should be comprehensively evaluated.展开更多
基金Special Research Program of Tianjin Municipal Education Commission(Psychological Health Education)(2020ZXXL-GX03G)2022 School-level Cultivation Project of Hetian Polytechnic(HZ202310).
文摘In order to study the restoration of road landscape space,subjective evaluation method was adopted to visually evaluate different road spaces in Tianjin University with college students as the research objects.Using random block design,9 plots were quantitatively studied by Perceived Restorativeness Scale(PRS)from four dimensions:alienation,compatibility,richness and attractiveness.The results show that gray space has the worst restorative effect in the dimension of alienation,and can not bring people the feeling of being away from daily trivialities;in terms of compatibility dimension,green and blue spaces have better restorative effects;richness dimension has no obvious influence on the restoration of plots;in terms of attraction dimension,blue space has strong restorative ability and can easily attract people’s attention,while gray space has low attraction.There are differences in environmental restoration among different types of road space,and gray space,blue space and green space show weak,strong,and relatively stable restorative effects,respectively.
文摘The contamination levels and distribution characters of heavy metals in coastal waters and sediments from Tianjin Bohai Bay,China were examined.Pb and Zn were found as the main heavy metal pollutants in the coastal waters of the bay.High levels of Pb and Zn appeared especially near the estuary,indicating that river discharge was the main pollution source.Moreover,atmospheric deposition resulted in Pb contamination in the middle of the embayment.Analysis of data for the period 1987-2004 indicated that Pb pol...
文摘In this study sediment samples were collected from 13 sites of Haihe River in Tianjin City, China, sixteen of priority polycyclic aromatic hydrocarbons (PAHs) listed in USEPA were analyzed by means of GC-MS. The total concentrations of PAH ranged from 774.81 to 255371.91 ng/g dw, and two to four rings of PAHs were dominant in sediment samples. Molecular ratios, such as phenanthrene/anthracene, fluoranthene/pyrene and low-molecular-weight PAH/high-molecular-weight PAH, were used to study the possible sources of pollution. It indicated a mixed pattern of parolytic and petrogenic inputs of PAHs in sediments in Haihe River. The petrogenic PAHs may be mainly derived from the leakage of refined products, e.g., gasoline, diesel fuel and fuel oil vehicle traffics or gas stations from urban area. The pyrolytic PAHs might be from the discharge of industrial wastewater and the emission of atmospheric particles from petrochemical factories. In addition, the levels of PAHs in the urban and industrial areas are far beyond the values reported from other rivers and marine systems reported. This situation may be due to polluted discharging from some petrochemical industrial manufactories and worse traffic conditions in Tianjin.
基金supported by the National NaturalScience Foundation of China (No. 40473045)
文摘The contents and distribution of 20 polycyclic aromatic hydrocarbons (PAHs) and heterocyclic aromatic hydrocarbons (HAHs) were investigated in 16 soil profiles of Beijing and Tianjin region. Transport of high molecular weight PAHs (HMWPAHs) and the correlation between total organic carbon (TOC) and their concentrations were also discussed. The results indicated that highly contaminated sites were located at urban or wastewater irrigation areas and pollutants mainly accumulated in topsoil (〈 40 cm), with a sharp content decrease at the vertical boundary of 30-40 cm. Total PAHs/HAHs concentrations in soils from Tianjin were markedly greater than those from Beijing. Even the contents at bottoms of soil profiles in Tianjin were higher than those in topsoils of Beijing soil profile. HMWPAHs dominated the PAH profiles, exhibiting a uniform distribution of pyrogenic origin between topsoils and deep layers. Furthermore, the percentages of HMWPAHs remained relative constant with the depth of soil profiles, which were consistent with the distribution of particulate matter-associated PAHs in the local atmospheric environments. Therefore, HMWPAHs transport with particulates might be the predominant source found in soil profiles.
基金National Basic Research Program of China (973 Program), No.2002CB412507
文摘Taken fractal dimension, compact ratio, urban centroid and urban principal axis as the urban spatial characteristic indices, Tianjin city's urban area is investigated in the last 26 years in a quantitative perspective, and its traits and changes during different periods are also analyzed. It is clear that these indices can not only scientifically and explicitly assess the urban morphology, urban direction and its changes and trends, but also uncover long-term effects of economy and urban planning on urban morphology.
基金This paper is financially supported by the National Natural Science Foundation of China (Nos .49802012 ,40472065) .
文摘Both the macroscopic feature and the sequence-stratigraphic position of the molar-tooth structure developed in the third member of the Gaoyuzhuang (高于庄) Formation at the Jixian (蓟县) Section in Tianjin (天津) can provide some useful information about its origin and can reveal some problems to be further researched in the future. The Mesoproterozoic Gaoyuzhuang Formation is a set of 1 600 m thick carbonate strata. This formation can be divided into four members. The first member is mainly made up of stromatolitic dolomites; the second is marked by a set of manganese dolomites; the third is mainly composed of lamina limestones with the development of molar-tooth strcutures; the fourth is a set of stromatolitic-lithoherm dolomites. According to lithofacies and its succession, several types of meter-scale cycles can be discerned in the Gaoyuzhuang Formation: the L-M type, the subtidal type and the peritidal type. There is a regularly vertical stacking pattern for meter-scale cycles in the third-order sequence. Therefore, the Mesoproterozoic Gaoyuzhuang Formation can be divided into 13 third-order sequences (SQ1 to SQ13 ) and can further be grouped into 4 second-order sequences. The third member is marked by lamina limestones and can be grouped into three third-order sequences (SQ9 to SQ11 ). The molar-tooth structure is developed in the middle part of the third sequence, i.e. SQH , in the third member. Several features of this kind of molar-tooth structure reflect some features of carbonate sedimentation in the Precambrian, such as the particular configuration, abundant organic matter, and easy silication. Stromatolites are chiefly formed in a shallow tidal-flat environment; lamina are mainly formed in the shallow ramp and molar-tooth structures are mainly generated in a relatively more deep-water environment from the middle to the deep ramp. Therefore, similar to stromatolite and lamina, the molartooth structure might also be a kind of bio-sedimentation structure. This suggestion is based on macroscopic observation and the sedimentary-facies analysis of the molar-tooth structures from the sequencestratigraphic position. These features of Precambrian sedimentation also reveal the problem of Precambrian carbonate sedimentation. With more detailed study, a more practical solution for these problems may be obtained in the future.
基金the project"A Study of the Cycles and Events for the Mesoproterozoic Jixian System in the Yan Mountain Region,northern China"(Nos.49802012, 40472065)financially supported by the National Foundation of Natural Sciences of China
文摘Molar-tooth(MT) structure is an enigmatic sedimentary structure consisting of variously-shaped cracks and voids filled with a characteristically uniform,equant calcite microspar.It is globally distributed but temporally restricted to rocks from Neoarchean to Neoproterozoic age.The origin of MT structures has been debated for more than a century and the topic continues to be highly contentious.Some features of MT structure occurring in micritic limestones of the Mesoproterozoic Gaoyuzhuang Formation(ca.1500 Ma to ca.1400 Ma),Jixian section,Tianjin City,North China show that:1) there is a definite interface or lining,rich in organic material and pyrite,between the MT crack-filling calcite microspar and the micritic host rock,which is also rich in organic matter;2) the micritic host rocks are notable for the absence of stromatolites and microbial laminites;3) distinctive conglomeratic lag deposits made up of intraclasts of MT microspar result from storm reworking of the MT structures;4) the MT structure is associated with possible algal megafossils such as Chuaria;5) the MT microspar is made up of the larger calcite crystal and the MT crack is marked by the diversity of configurations;6) both the TOC content and the carbon-isotopic value(δ^(13)C_(PDB)) among the host rock, the MT microspar and the possible algae fossil are obviously different.For the forming mechanism of the Gaoyuzhuang MT structure,these features can still indicate that:A) the MT microspar was formed by rapid precipitation and lithification;B) the MT microspar precipitated directly within the cracks; C) the decomposition of organic matter within the host micrite might be the chief mechanism producing gas bubbles;D) microscale gas-sediment interaction led to the generation of the MT cracks and the precipitation of microspar therein;E) the MT cracks might represent the track of migration and expansion of gas bubbles,and that the recrystallization of host micrites cannot be eliminated during forming process of the MT microspar;F) the MT structure is occurred in early diagenetic period;and G) the formation of MT microspars is a complex diagenetic process.Therefore,model of the microbially-induced gas-bubble expansion and migration is the best interpretation for the formation of the MT structure.Effectively,MT structures are a type of sedimentary structure that is formed in the early diagenetic period and is related to microbial activities and organic matter degradation.
基金supported by the Research Fund of Tianjin Health and Family Planning Commission 2015KY18Science and Technology Major Project of Chinese Preventive Medicine Association Q2017A1225
文摘The epidemiologic characteristics of 631 infant pertussis cases 〈 12 months, which accounted for 57.42% of the total cases, were analyzed by descriptive epidemiology in Tianjin, between 2010 and 2015. The incidence of infants was 104.66/100,000, which was 118 times higher than in other age groups (P 〈 0.001). The primary type of pertussis simultaneously presented in households was adult-to-infant (70.51%). The parents were identified as the source of infection in 80.18% of cases for infants. The positive rate of placental antibody transfer was 31.06% and 3.13% for 3-month-old infants. Infants presented the highest age-specific pertussis incidence. The most important reason was parents were the important sources of infection, and secondly the lower level of antibodies in neonates and the rapid waning of maternal antibody titer.
文摘High concentrations of air pollutants such as total suspended particulates(TSP) and sulfur dioxide(SO_2) have serious impacts on nearby populations. In this paper, a survey of rural Tianjin residents' willingness-to-pay for health improvement was reported on, and the MBDC(multiple bounded discrete choice) model was adopted to study the respondents' willingness-to-pay to prevent respiratory illnesses. The results showed that the willingness-to-pay for health improvement was affected by respondents' health condition, work situation and environmental awareness, but not by personal habits, such as smoking. If person's willingness-to-pay to avoid respiratory diseases can be considered equal to the cost to personal health caused by air pollution, the total cost will reach 538×10 6 RMB Yuan(RMB, equal to 65 million USD) per year.
基金jointly sponsored by the National Basic Research Program of China(973 Program)(Grant No.2013CB430202)the National Natural Science Foundation of China(Grant No.41401056)+1 种基金the China Meteorological Administration Special Public Welfare Research Fund(Grant No.GYHY201406001)the Research Innovation Program for College Graduates of Jiangsu Province(Grant No.KYLX15 0858)
文摘In this study, regional persistent haze events(RPHEs) in the Beijing–Tianjin–Hebei(BTH) region were identified based on the Objective Identification Technique for Regional Extreme Events for the period 1980–2013. The formation mechanisms of the severe RPHEs were investigated with focus on the atmospheric circulation and dynamic mechanisms. Results indicated that:(1) 49 RPHEs occurred during the past 34 years.(2) The severe RPHEs could be categorized into two types according to the large-scale circulation, i.e. the zonal westerly airflow(ZWA) type and the high-pressure ridge(HPR) type. When the ZWA-type RPHEs occurred, the BTH region was controlled by near zonal westerly airflow in the mid–upper troposphere.Southwesterly winds prevailed in the lower troposphere, and near-surface wind speeds were only 1–2 ms^-1. Warm and humid air originating from the northwestern Pacific was transported into the region, where the relative humidity was 70% to 80%, creating favorable moisture conditions. When the HPR-type RPHEs appeared, northwesterly airflow in the mid–upper troposphere controlled the region. Westerly winds prevailed in the lower troposphere and the moisture conditions were relatively weak.(3) Descending motion in the mid-lower troposphere caused by the above two circulation types provided a crucial dynamic mechanism for the formation of the two types of RPHEs. The descending motion contributed to a reduction in the height of the planetary boundary layer(PBL), which generated an inversion in the lower troposphere. This inversion trapped the abundant pollution and moisture in the lower PBL, leading to high concentrations of pollutants.
基金Natural Science Foundation of Guangxi(Nos.2018GXNSFBA050006,2020GXNSFBA159033)Wuhan Science and Technology Plan Project(No.2019010702011314)+2 种基金Guangxi Science and Technology Plan Project(No.GUIKE AD19110107)National Natural Science Foundation of China(Nos.42064003,42064002)Guangxi Universities Young and Middle-aged Teachers’Basic Scientific Research Ability Improvement Project(No.2020KY0603)。
文摘Tianjin is one of the inland cities with the most severe cases of subsidence hazard in China.The majority of the existing studies have mainly focused on Beijing-Tianjin-Hebei,and little attention has been given to Tianjin.In addition,these existing studies are short-term investigations,lacking long-term monitoring of surface subsidence.In the present study,we use the Small Baseline Subset Interferometric Synthetic Aperture Radar(SBAS-InSAR)technique to monitor the subsidence process in Tianjin between 2015 and 2020 and reveal its spatial and temporal variation.We divided the 44-view Sentinel-1A image data into three periods to avoid the effect of temporal and spatial decoherence by extracting the surface deformation field in Tianjin.We finally verified the accuracy and reliability of the inversion results using second-order leveling data.Results showed that the correlation coefficient r between the two reached 0.89,and the root mean square error was 4.84 mm/y.Obvious subsidence funnels exist in Tianjin,mainly in the towns of Wangqingtuo and Shengfang.These subsidence funnels have a subsidence deformation rate of-136.2 mm/y and a maximum cumulative settlement of-346.3 mm within the study period.The subsidence area tends to extend to the southwest.The analysis of annual rainfall,groundwater resource extraction,spatial location distribution of industrial areas combined with SBAS-InSAR inversion results indicates that overextraction of groundwater resources is the main cause of land subsidence in the area.Therefore,strict control of groundwater extraction is the main approach to mitigate land subsidence effectively.
基金supported by grants from Basic Scientific Research Business Expenses Foundation of Huazhong University of Science and Technology,China(No2014QN136)Natural Science Foundation of Hube Province,China(No.2014CFB955)
文摘The current situation of medical staff's awareness about high alert medication was investigated in order to promote safe medication and standardized management of the high alert medication in China. Twenty questions were designed concerning elementary knowledge of high alert medications, storage management, medication issues and risks. In order to understand the knowledge level and education status of high alert medication, a convenient survey was conducted among 300 medical staffs in Tianjin. Medical staff's average score of high alert medication knowledge was 12.43±0.27, and the average scores of elementary knowledge of high alert medication, storage management, medication issues and risks were 3.38±0.11, 2.46±0.14, 3.17±0.11 and 3.41±0.12 respectively. Occupation(F=4.86, P=0.003), education background(F=5.57, P=0.019) and professional titles(F=13.44, P≤0.001) contributed to the high alert medications knowledge scores. Currently, the most important channel to obtain high alert medication knowledge was hospital files or administrative rules, and clinical pharmacist seminars were the most popular education form. It was suggested that the high alert medication knowledge level of the medical staff needs to increase, and it might benefit from targeted, systematic and diverse training to the medical staff working in the different circulation nodes of the medications. Further research to develop and validate the instrument is needed.
基金supported by the National Natural Science Foundation of China (40674016)Earthquake Research Fund of Ministry of Science and Technology of China ((2007)203/8-53)
文摘Taking Tianjin as an example, this paper proposed a methodology and process for evaluating near-fault strong ground motions from future earthquakes to mitigate earthquake damage for the metropolitan area and important engineering structures. The result of strong ground motion was predicted for Tianjin main faults by the hybrid method which mainly con- sists of 3D finite difference method and stochastic Green's function. Simulation is performed for 3D structures of Tianjin re- gion and characterized asperity models. The characterized asperity model describing source heterogeneity is introduced fol- lowing the fault information from the project of Tianjin Active Faults and Seismic Hazard Assessment. We simulated the worst case that two earthquakes separately occur. The results indicate that the fault position, rupture process and the sedi- mentary deposits of the basin significantly affect amplification of the simulated ground motion. Our results also demonstrate the possibility of practical simulating wave propagation including basin induced surface waves in broad frequency-band, for seismic hazard analysis near the fault from future earthquakes in urbanized areas.
基金financially supported by the National Natural Science Foundation of China (31560135, 41361100)the Discipline Construction Fund Project of Gansu Agricultural University (GAU-XKJS-2018-104, GAU-XKJS-2018-108)the Gansu Science and Technology Support Program (1604FKCA088)
文摘Launched in 2002, the Beiing–Tianjin Sand Source Control Project (BTSSCP) is an ecological restoration project intended to prevent desertification in China. Evidence from multiple sources has confirmed increases in vegetation growth in the BTSSCP region since the initiation of this project. Precipitation and essential climate variable-soil moisture (ECV-SM) conditions are typically considered to be the main drivers of vegetation growth in this region. Although many studies have investigated the inter-annual variations of vegetation growth, few concerns have been focused on the annual and seasonal variations of vegetation growth and their climatic drivers, which are crucial for understanding the relationships among the climate, vegetation, and human activities at the regional scale. Based on the normalized difference vegetation index (NDVI) derived from MODIS and the corresponding climatic data, we explored the responses of vegetation growth to climatic factors at annual and seasonal scales in the BTSSCP region during the period 2000–2014. Over the study region as a whole, NDVI generally increased from 2000 to 2014, at a rate of 0.002/a. Vegetation growth is stimulated mainly by the elevated temperature in spring, whereas precipitation is the leading driver of summer greening. In autumn, positive effects of both temperature and precipitation on vegetation growth were observed. The warming in spring promotes vegetation growth but reduces ECV-SM. Summer greening has a strong cooling effect on land surface temperature. These results indicate that the ecological and environmental consequences of ecological restoration projects should be comprehensively evaluated.