Based on the abundant information from drilling, cores, and logging, the influence of topography, size of rivers and lakes, climate changes and the lake level's fluctuation on the sandbodies at shallow-water delta fr...Based on the abundant information from drilling, cores, and logging, the influence of topography, size of rivers and lakes, climate changes and the lake level's fluctuation on the sandbodies at shallow-water delta front are systematically summarized and the sedimentary dynamic processes are analyzed. The interwell communication among the sandbodies and their planar distribution revealed from the hydrodynamic features of the development wells are integrated during the analysis. The fundamental requirements for the development of the shallow-water delta included flat topography and uniform subsiding rate. The delta plain was connected smoothly with the wide delta front and predelta, without the three-fold structure of topset, foreset, and bottomset as defined in the Gilbert Delta Model. Because of the weak fluvial effect and the lake energy is strong, the small and scattered shallow-water delta is destroyed by the scouring-backwashing, coastal current, and lake wave, resulting in the coastal sheet deposition. As the fluvial effect became stronger and the lake energy became weaker, the shape of the shallow-water deltas transferred from sheets to lumps and then branches.展开更多
Objective China's petroleum exploration has entered a new stage of finding deeply buried thin sandbodies lbr the abundant oil resources they contain. Here thin sandbodies refer to those less than 10 m in thickness, ...Objective China's petroleum exploration has entered a new stage of finding deeply buried thin sandbodies lbr the abundant oil resources they contain. Here thin sandbodies refer to those less than 10 m in thickness, or even less than 1-2 m. It is difficult to depict thin-layer sandbodies of different genetic types using conventional core, well logging and seismic data due to their limited vertical resolution in petroliferous basins. However, seismic sedimentology provides a new research method especially tbr thin sandbody interpretation, i.e., validating interpreted sedimentary sandbodies from 3D seismic data based on horizontal resolution, stratal slice and seismic geomorphology interpretation. At present, a series of studies on seismic sedimentology in North America marine basins and elsewhere have been completed successfully and are relevant to the exploration and development of oil and gas fields.展开更多
In shallow-water areas,the marine magnetotelluric(MT)method faces a challenge in the investigation of seabed conductivity structures due to electrical and magnetic noises induced by ocean waves,which seriously contami...In shallow-water areas,the marine magnetotelluric(MT)method faces a challenge in the investigation of seabed conductivity structures due to electrical and magnetic noises induced by ocean waves,which seriously contaminate MT data.Ocean waves can affect electric and magnetic fields to different extents.In general,their influence on magnetic fields is considerably greater than that on electric fields.In this paper,a complex adaptive filter is adopted to reduce wave-induced magnetic noises in the frequency domain.The processing results of synthetic and measured MT data indicate that the proposed method can effectively reduce wave-induced magnetic noises and provide reliable apparent resistivity and phase data.展开更多
Based on the analysis of core,logging,and testing data,the fourth member of the Cretaceous Quantou Formation(K_(2)q^(4))in the Sanzhao depression,Songliao Basin,is investigated in order to understand the sedimentary c...Based on the analysis of core,logging,and testing data,the fourth member of the Cretaceous Quantou Formation(K_(2)q^(4))in the Sanzhao depression,Songliao Basin,is investigated in order to understand the sedimentary characteristics and hydrocarbon exploration significance of a retrograding shallow-water delta.The results show that during the sedimentary period of K_(2)q^(4),the Sanzhao depression with a gentle basement experienced stable tectonic subsidence and suffered a long-term lake level rise caused by paleoclimate changes(from semiarid to semihumid),the K_(2)q^(4)in the study area were dominated by a fining-upward deltaic succession and had relatively stable thickness.From the bottom to the top,the color of mudstone gradually changes from purplish-red to gray and grayish-green,the contents of caliche nodules decrease gradually,while the presence of pyrite in sediments becomes frequent.Channel sandstones mainly composed of siltstone and fine sandstone with developed high-energy sedimentary structures constitute the main sand bodies of deltaic deposits,but the scale of channel sandstones decrease upward.Despite the long-term lake level rise and fining-upward sedimentary succession,purplish-red mudstone,caliche nodules and thin channel sandstones are still broadly distributed in the study area,and thin channel sandstones can be found at the top of K_(2)q^(4)covered by the black oil shale of Qingshankou Formation.These assertations suggest that the study area was dominated by retrograding shallow-water delta deposits during the sedimentary period of K_(2)q^(4).In comparison with modern Poyang Lake,we infer that during the sedimentary period of K_(2)q^(4),the study area experienced frequent lake level fluctuations triggered by paleoclimate changes despite the long-term lake level rise,and the lake level fluctuations control the deposition of retrograding shallow-water delta.In addition,most of the thin channel sandstones distributed at the top of K_(2)q^(4)and covered by black oil shale are generally immersed in oil,indicating that the thin channel sandstones formed at the top of a retrograding shallow-water delta sedimentary succession are favorable targets for lithological reservoir exploration.展开更多
Shallow-water deltas are now a research focus of international sedimentology. Researchers have recently discovered that water depth is an important controlling factor for the development of shallow deltas, and that si...Shallow-water deltas are now a research focus of international sedimentology. Researchers have recently discovered that water depth is an important controlling factor for the development of shallow deltas, and that significant differences exist between shallow-water deltas and the traditional Gilbert deltas. The identification marks of shallow-water deltas are critical for better understanding sedimentary characteristics of these deltas. In continental basins, especially China's Mesozoic and Cenozoic continental basins, shallow-water deltas are widely developed. Thus, this work took the Songliao Basin as an example to analysis this kind of deltas.展开更多
Approximately 12-72 million people worldwide are co-infected with hepatitis B virus(HBV)and hepatitis delta virus(HDV).This concurrent infection can lead to several severe outcomes with hepatic disease,such as cirrhos...Approximately 12-72 million people worldwide are co-infected with hepatitis B virus(HBV)and hepatitis delta virus(HDV).This concurrent infection can lead to several severe outcomes with hepatic disease,such as cirrhosis,fulminant hepatitis,and hepatocellular carcinoma,being the most common.Over the past few decades,a correlation between viral hepatitis and autoimmune diseases has been reported.Furthermore,autoantibodies have been detected in the serum of patients co-infected with HBV/HDV,and autoimmune features have been reported.However,to date,very few cases of clinically significant autoimmune hepatitis(AIH)have been reported in patients with HDV infection,mainly in those who have received treatment with pegylated interferon.Interestingly,there are some patients with HBV infection and AIH in whom HDV infection is unearthed after receiving treatment with immunosuppressants.Consequently,several questions remain unanswered with the challenge to distinguish whether it is autoimmune or“autoimmune-like”hepatitis being the most crucial.Second,it remains uncertain whether autoimmunity is induced by HBV or delta virus.Finally,we investigated whether the cause of AIH lies in the previous treatment of HDV with pegylated interferon.These pressing issues should be elucidated to clarify whether new antiviral treatments for HDV,such as Bulevirtide or immu-nosuppressive drugs,are more appropriate for the management of patients with HDV and AIH.展开更多
Groundwater resources are the main sources of water used to supply drinking water to the population of the Ouémé Delta via the Continental Terminal aquifer. Urbanization, population growth, and agricultural ...Groundwater resources are the main sources of water used to supply drinking water to the population of the Ouémé Delta via the Continental Terminal aquifer. Urbanization, population growth, and agricultural and industrial activities have resulted in a deterioration in the quality of these resources. To assess the quality of the delta’s groundwater and its suitability for human consumption and irrigation, a total of fourteen (14) physico-chemical parameters were analyzed in some forty existing water points between September 2020 and March 2021, using standard water analysis techniques. The values obtained were compared with the potability standards recommended by the World Health Organization (WHO) and the Republic of Benin and were subjected to statistical analysis (principal component analysis (PCA)). In addition, methods for determining the suitability of water for irrigation were used. The results showed that the waters are acidic to slightly neutral and influenced by ambient temperature. In addition, the waters are moderately mineralized, with conductivities (24 - 1205 μS/cm) in line with WHO standards. A comparison of the analytical results of the WHO (2017) and Benin (2001) standards indicates that the majority of the waters studied are of good quality for all the chemical parameters considered. Nevertheless, some samples show levels of nitrates (21%), potassium (14% to 16%), calcium (13%), ammonium (12%), nitrites (8%) and bicarbonates (10%) over their respective standards. The Wilcox and Riverside diagrams indicate that the majority of waters (90%) have excellent suitability for irrigation and no negative effect on soil fertilization.展开更多
Due to their high reliability and cost-efficiency,submarine pipelines are widely used in offshore oil and gas resource engineering.Due to the interaction of waves,currents,seabed,and pipeline structures,the soil aroun...Due to their high reliability and cost-efficiency,submarine pipelines are widely used in offshore oil and gas resource engineering.Due to the interaction of waves,currents,seabed,and pipeline structures,the soil around submarine pipelines is prone to local scour,severely affecting their operational safety.With the Yellow River Delta as the research area and based on the renormalized group(RNG)k-εturbulence model and Stokes fifth-order wave theory,this study solves the Navier-Stokes(N-S)equation using the finite difference method.The volume of fluid(VOF)method is used to describe the fluid-free surface,and a threedimensional numerical model of currents and waves-submarine pipeline-silty sandy seabed is established.The rationality of the numerical model is verified using a self-built waveflow flume.On this basis,in this study,the local scour development and characteristics of submarine pipelines in the Yellow River Delta silty sandy seabed in the prototype environment are explored and the influence of the presence of pipelines on hydrodynamic features such as surrounding flow field,shear stress,and turbulence intensity is analyzed.The results indicate that(1)local scour around submarine pipelines can be divided into three stages:rapid scour,slow scour,and stable scour.The maximum scour depth occurs directly below the pipeline,and the shape of the scour pits is asymmetric.(2)As the water depth decreases and the pipeline suspension height increases,the scour becomes more intense.(3)When currents go through a pipeline,a clear stagnation point is formed in front of the pipeline,and the flow velocity is positively correlated with the depth of scour.This study can provide a valuable reference for the protection of submarine pipelines in this area.展开更多
With the loss of substantial natural wetlands in coastal zones,artificial wetlands provide alternative habitats for many shorebirds.Scientific management of artificial wetlands used by shorebirds plays an important ro...With the loss of substantial natural wetlands in coastal zones,artificial wetlands provide alternative habitats for many shorebirds.Scientific management of artificial wetlands used by shorebirds plays an important role in maintaining the stability of shorebird population.Satellite tracking technique can obtain high-precision location information of individuals day and night,providing a good technical support for the study of quantitative relationship between waterfowls and their habitats.In this study,satellite tracking method,Remote Sensing(RS)and Geographic Information System(GIS)technology were used to analyze the activity pattern and habitat utilization characteristics of Pied Avocet during breeding period in an artificial wetland complex in the Yellow River Delta(YRD),China.The results showed that the breeding Pied Avocets had a small range of activity,with a total core and main home range of 33.10 km^(2) and 216.30 km^(2),respectively.This species tended to forage in the pond and salt pan during the day and night,respectively,with an unfixed staying time in the breeding ground.The distance between breeding ground and feeding ground was less than 6 km.It is emphasized that in addition to improving the conditions of the remaining natural habitats,effective managing artificial habitats is a priority for shorebird conservation.This research could provide reference for the management of artificial wetlands in coastal zones and supply technique support for the protection of shorebirds and their habitats,and alleviate human-bird conflicts and sustainable development of coastal zones.展开更多
The Zambezi Delta basin is a passive marginal basin located on the East African coast that has good oil and gas exploration potential.Due to the special geological evolutionary background of the Beira High in the Zamb...The Zambezi Delta basin is a passive marginal basin located on the East African coast that has good oil and gas exploration potential.Due to the special geological evolutionary background of the Beira High in the Zambezi Delta basin,it has a low gravity anomaly,and the existing seismic survey lines do not cover the whole basin;therefore,it is difficult to interpret the structural characteristics of the whole basin based solely on gravity or seismic data.Based on satellite altimetry gravity anomaly data,this study infers the distribution characteristics of faults in the Zambezi Delta basin by using the normalized vertical derivative of the total horizontal derivative(NVDR-THDR)technique.Then,constrained by seismic data,the gravity anomaly at the Moho interface is extracted by using the fast forward method of the double-interface model of the gravity anomaly,and this anomaly is then removed from the Bouguer gravity anomaly to obtain the sedimentary layer gravity anomaly.The thickness of the sedimentary strata is obtained by inversing the sedimentary basement depth of the whole basin.Then,uplifts and depressions are divided based on a sedimentary layer thickness of 3 km.This research demonstrates that the Zambezi Delta basin mainly features nearly SN-trending and NE-trending faults and that these faults exhibit east-west partitioning.The nearly SN-trending strike-slip faults controlled the sedimentary development of the basin,and the NE-trending tensile faults may have acted as migration channels for oil,gas and magma.The“overcompensation”effect of the Moho interface gravity anomaly on the gravity anomaly of the sedimentary layer is caused by the depression of the Moho interface beneath the Beira High,which results in a low gravity anomaly value for the Beira High.The pattern of uplifts and depressions trends NE and has the structural characteristics of east-west blocks.展开更多
Based on the supply-side perspective,the improved STIRPAT model is applied to reveal the mechanisms of supply-side factors such as human,capital,technology,industrial synergy,institutions and economic growth on carbon...Based on the supply-side perspective,the improved STIRPAT model is applied to reveal the mechanisms of supply-side factors such as human,capital,technology,industrial synergy,institutions and economic growth on carbon emissions in the Yangtze River Delta(YRD)through path analysis,and to forecast carbon emissions in the YRD from the baseline scenario,factor regulation scenario and integrated scenario to reach the peak.The results show that:(1)Jiangsu's high carbon emission pattern is the main reason for the YRD hindering the synergistic regulation of carbon emissions.(2)Human factors,institutional factors and economic growth factors can all contribute to carbon emissions in the YRD region,while technological and industrial factors can generally suppress carbon emissions in the YRD region.(3)Under the capital regulation scenario,the YRD region has the highest level of carbon emission synergy,with Jiangsu reaching its peak five years earlier.Under the balanced regulation scenario,the YRD region as a whole,Jiangsu,Zhejiang and Anhui reach the peak as scheduled.展开更多
Based on the 3D seismic data and the analysis and test data of lithology,electricity,thin sections and chronology obtained from drilling of the Qiongdongnan Basin,the characteristics and the quantitative analysis of t...Based on the 3D seismic data and the analysis and test data of lithology,electricity,thin sections and chronology obtained from drilling of the Qiongdongnan Basin,the characteristics and the quantitative analysis of the source-sink system are studied of the third member of the Upper Oligocene Lingshui Formation(Ling 3 Member)in the southern fault step zone of the Baodao Sag.First,the YL10 denudation area of the Ling 3 Member mainly developed two fluvial systems in the east and west,resulting in the formation of two dominant sand transport channels and two delta lobes in southern Baodao Sag,which are generally large in the west and small in the east.The evolution of the delta has experienced four stages:initiation,prosperity,intermittence and rejuvenation.Second,the source-sink coupled quantitative calculation is performed depending on the parameters of the delta sand bodies,including development phases,distribution area,flattening thickness,area of different parent rocks,and sand-forming coefficient,showing that the study area has the material basis for the formation of large-scale reservoir.Third,the drilling reveals that the delta of the Ling 3 Member is dominated by fine sandstone,with total sandstone thickness of 109-138 m,maximum single-layer sandstone thickness of 15.5-30.0 m,and sand-to-strata ratio of 43.7%-73.0%,but the physical properties are different among the fault steps.Fourth,the large delta development model of the small source area in the step fault zone with multi-stage uplift is established.It suggests that the episodic uplift provides sufficient sediments,the fluvial system and watershed area control the scale of the sand body,the multi-step active fault steps dominate the sand body transport channel,and local fault troughs decide the lateral propulsion direction of the sand body.The delta of the Ling 3 Member is coupled with fault blocks to form diverse traps,which are critical exploration targets in southern Baodao Sag.展开更多
The Yellow River Delta(YRD), a critical economic zone along China's eastern coast, also functions as a vital ecological reserve in the lower Yellow River. Amidst rapid industrialization and urbanization, the regio...The Yellow River Delta(YRD), a critical economic zone along China's eastern coast, also functions as a vital ecological reserve in the lower Yellow River. Amidst rapid industrialization and urbanization, the region has witnessed significant land use/cover changes(LUCC), impacting ecosystem services(ES) and ecological security patterns(ESP). Investigating LUCC's effects on ES and ESP in the YRD is crucial for ecological security and sustainable development. This study utilized the PLUS model to simulate 2030 land use scenarios, including natural development(NDS), economic development(EDS), and ecological protection scenarios(EPS). Subsequently, the InVEST model and circuit theory were applied to assess ES and ESP under varying LUCC scenarios from 2010 to 2030. Findings indicate:(1) Notable LUCC from 2010 to 2030, marked by decreasing cropland and increasing construction land and water bodies.(2) From 2010 to 2020, improvements were observed in carbon storage,water yield, soil retention, and habitat quality, whereas 2020–2030 saw increases in water yield and soil retention but declines in habitat quality and carbon storage. Among the scenarios, EPS showed superior performance in all four ES.(3) Between 2010 and 2030, ecological sources, corridors, and pinchpoints expanded, displaying significant spatial heterogeneity. The EPS scenario yielded the most substantial increases in ecological sources,corridors, and pinchpoints, totaling 582.89 km^(2), 645.03 km^(2),and 64.43 km^(2), respectively. This study highlights the importance of EPS, offering insightful scientific guidance for the YRD's sustainable development.展开更多
BACKGROUND The coronavirus disease 2019(COVID-19)virus has been a world-known pan-demic since February 2020.Multiple variances had been established;the most common variants in Israel were omicron and delta.AIM To anal...BACKGROUND The coronavirus disease 2019(COVID-19)virus has been a world-known pan-demic since February 2020.Multiple variances had been established;the most common variants in Israel were omicron and delta.AIM To analyze and compare laboratory values in the"omicron"and"delta"variants of the coronavirus by conducting follow-up examinations and laboratory audits on COVID-19 patients admitted to our institution.METHODS A retrospective study,two groups,50 patients in each group.Patients examined positive for COVID-19 were divided into groups according to the common variant at the given time.We reviewed demographic data and laboratory results such as complete blood count and full chemistry,including electrolytes and coagulation parameters.RESULTS The mean age was 52%,66.53±21.7 were female.No significance was found comparing laboratory results in the following disciplines:Blood count,hemo-globin,and lymphocytes(P=0.41,P=0.87,P=0.97).Omicron and delta variants have higher neutrophil counts,though they are not significantly different(P=0.38).Coagulation tests:Activated paritial thromoplastin test and international normalized ratio(P=0.72,P=0.68).We found no significance of abnormality for all electrolytes.CONCLUSION The study compares laboratory results of blood tests between two variants of the COVID-19 virus–omicron and delta.We found no significance between the variants.Our results show the need for further research with larger data as well as the need to compare all COVID-19 variants.展开更多
文摘Based on the abundant information from drilling, cores, and logging, the influence of topography, size of rivers and lakes, climate changes and the lake level's fluctuation on the sandbodies at shallow-water delta front are systematically summarized and the sedimentary dynamic processes are analyzed. The interwell communication among the sandbodies and their planar distribution revealed from the hydrodynamic features of the development wells are integrated during the analysis. The fundamental requirements for the development of the shallow-water delta included flat topography and uniform subsiding rate. The delta plain was connected smoothly with the wide delta front and predelta, without the three-fold structure of topset, foreset, and bottomset as defined in the Gilbert Delta Model. Because of the weak fluvial effect and the lake energy is strong, the small and scattered shallow-water delta is destroyed by the scouring-backwashing, coastal current, and lake wave, resulting in the coastal sheet deposition. As the fluvial effect became stronger and the lake energy became weaker, the shape of the shallow-water deltas transferred from sheets to lumps and then branches.
基金financially supported by the National Science Foundation of China(Grant No.41272133)
文摘Objective China's petroleum exploration has entered a new stage of finding deeply buried thin sandbodies lbr the abundant oil resources they contain. Here thin sandbodies refer to those less than 10 m in thickness, or even less than 1-2 m. It is difficult to depict thin-layer sandbodies of different genetic types using conventional core, well logging and seismic data due to their limited vertical resolution in petroliferous basins. However, seismic sedimentology provides a new research method especially tbr thin sandbody interpretation, i.e., validating interpreted sedimentary sandbodies from 3D seismic data based on horizontal resolution, stratal slice and seismic geomorphology interpretation. At present, a series of studies on seismic sedimentology in North America marine basins and elsewhere have been completed successfully and are relevant to the exploration and development of oil and gas fields.
基金supported by the National Natural Science Foundation of China(Nos.91958210 and 41904075)。
文摘In shallow-water areas,the marine magnetotelluric(MT)method faces a challenge in the investigation of seabed conductivity structures due to electrical and magnetic noises induced by ocean waves,which seriously contaminate MT data.Ocean waves can affect electric and magnetic fields to different extents.In general,their influence on magnetic fields is considerably greater than that on electric fields.In this paper,a complex adaptive filter is adopted to reduce wave-induced magnetic noises in the frequency domain.The processing results of synthetic and measured MT data indicate that the proposed method can effectively reduce wave-induced magnetic noises and provide reliable apparent resistivity and phase data.
基金financially supported by the National Science and Technology Major Project of China(H.M.Y.,grant number 2016ZX05013006-006)Natural Science Foundation of Hubei Province of China(L.H.,grant number 2020CFB745)
文摘Based on the analysis of core,logging,and testing data,the fourth member of the Cretaceous Quantou Formation(K_(2)q^(4))in the Sanzhao depression,Songliao Basin,is investigated in order to understand the sedimentary characteristics and hydrocarbon exploration significance of a retrograding shallow-water delta.The results show that during the sedimentary period of K_(2)q^(4),the Sanzhao depression with a gentle basement experienced stable tectonic subsidence and suffered a long-term lake level rise caused by paleoclimate changes(from semiarid to semihumid),the K_(2)q^(4)in the study area were dominated by a fining-upward deltaic succession and had relatively stable thickness.From the bottom to the top,the color of mudstone gradually changes from purplish-red to gray and grayish-green,the contents of caliche nodules decrease gradually,while the presence of pyrite in sediments becomes frequent.Channel sandstones mainly composed of siltstone and fine sandstone with developed high-energy sedimentary structures constitute the main sand bodies of deltaic deposits,but the scale of channel sandstones decrease upward.Despite the long-term lake level rise and fining-upward sedimentary succession,purplish-red mudstone,caliche nodules and thin channel sandstones are still broadly distributed in the study area,and thin channel sandstones can be found at the top of K_(2)q^(4)covered by the black oil shale of Qingshankou Formation.These assertations suggest that the study area was dominated by retrograding shallow-water delta deposits during the sedimentary period of K_(2)q^(4).In comparison with modern Poyang Lake,we infer that during the sedimentary period of K_(2)q^(4),the study area experienced frequent lake level fluctuations triggered by paleoclimate changes despite the long-term lake level rise,and the lake level fluctuations control the deposition of retrograding shallow-water delta.In addition,most of the thin channel sandstones distributed at the top of K_(2)q^(4)and covered by black oil shale are generally immersed in oil,indicating that the thin channel sandstones formed at the top of a retrograding shallow-water delta sedimentary succession are favorable targets for lithological reservoir exploration.
基金financially supported by the National Natural Science Foundation of China(grant No.41272133)
文摘Shallow-water deltas are now a research focus of international sedimentology. Researchers have recently discovered that water depth is an important controlling factor for the development of shallow deltas, and that significant differences exist between shallow-water deltas and the traditional Gilbert deltas. The identification marks of shallow-water deltas are critical for better understanding sedimentary characteristics of these deltas. In continental basins, especially China's Mesozoic and Cenozoic continental basins, shallow-water deltas are widely developed. Thus, this work took the Songliao Basin as an example to analysis this kind of deltas.
文摘Approximately 12-72 million people worldwide are co-infected with hepatitis B virus(HBV)and hepatitis delta virus(HDV).This concurrent infection can lead to several severe outcomes with hepatic disease,such as cirrhosis,fulminant hepatitis,and hepatocellular carcinoma,being the most common.Over the past few decades,a correlation between viral hepatitis and autoimmune diseases has been reported.Furthermore,autoantibodies have been detected in the serum of patients co-infected with HBV/HDV,and autoimmune features have been reported.However,to date,very few cases of clinically significant autoimmune hepatitis(AIH)have been reported in patients with HDV infection,mainly in those who have received treatment with pegylated interferon.Interestingly,there are some patients with HBV infection and AIH in whom HDV infection is unearthed after receiving treatment with immunosuppressants.Consequently,several questions remain unanswered with the challenge to distinguish whether it is autoimmune or“autoimmune-like”hepatitis being the most crucial.Second,it remains uncertain whether autoimmunity is induced by HBV or delta virus.Finally,we investigated whether the cause of AIH lies in the previous treatment of HDV with pegylated interferon.These pressing issues should be elucidated to clarify whether new antiviral treatments for HDV,such as Bulevirtide or immu-nosuppressive drugs,are more appropriate for the management of patients with HDV and AIH.
文摘Groundwater resources are the main sources of water used to supply drinking water to the population of the Ouémé Delta via the Continental Terminal aquifer. Urbanization, population growth, and agricultural and industrial activities have resulted in a deterioration in the quality of these resources. To assess the quality of the delta’s groundwater and its suitability for human consumption and irrigation, a total of fourteen (14) physico-chemical parameters were analyzed in some forty existing water points between September 2020 and March 2021, using standard water analysis techniques. The values obtained were compared with the potability standards recommended by the World Health Organization (WHO) and the Republic of Benin and were subjected to statistical analysis (principal component analysis (PCA)). In addition, methods for determining the suitability of water for irrigation were used. The results showed that the waters are acidic to slightly neutral and influenced by ambient temperature. In addition, the waters are moderately mineralized, with conductivities (24 - 1205 μS/cm) in line with WHO standards. A comparison of the analytical results of the WHO (2017) and Benin (2001) standards indicates that the majority of the waters studied are of good quality for all the chemical parameters considered. Nevertheless, some samples show levels of nitrates (21%), potassium (14% to 16%), calcium (13%), ammonium (12%), nitrites (8%) and bicarbonates (10%) over their respective standards. The Wilcox and Riverside diagrams indicate that the majority of waters (90%) have excellent suitability for irrigation and no negative effect on soil fertilization.
基金China Postdoctoral Science Foundation,Grant/Award Number:2023M731999National Natural Science Foundation of China,Grant/Award Number:52301326。
文摘Due to their high reliability and cost-efficiency,submarine pipelines are widely used in offshore oil and gas resource engineering.Due to the interaction of waves,currents,seabed,and pipeline structures,the soil around submarine pipelines is prone to local scour,severely affecting their operational safety.With the Yellow River Delta as the research area and based on the renormalized group(RNG)k-εturbulence model and Stokes fifth-order wave theory,this study solves the Navier-Stokes(N-S)equation using the finite difference method.The volume of fluid(VOF)method is used to describe the fluid-free surface,and a threedimensional numerical model of currents and waves-submarine pipeline-silty sandy seabed is established.The rationality of the numerical model is verified using a self-built waveflow flume.On this basis,in this study,the local scour development and characteristics of submarine pipelines in the Yellow River Delta silty sandy seabed in the prototype environment are explored and the influence of the presence of pipelines on hydrodynamic features such as surrounding flow field,shear stress,and turbulence intensity is analyzed.The results indicate that(1)local scour around submarine pipelines can be divided into three stages:rapid scour,slow scour,and stable scour.The maximum scour depth occurs directly below the pipeline,and the shape of the scour pits is asymmetric.(2)As the water depth decreases and the pipeline suspension height increases,the scour becomes more intense.(3)When currents go through a pipeline,a clear stagnation point is formed in front of the pipeline,and the flow velocity is positively correlated with the depth of scour.This study can provide a valuable reference for the protection of submarine pipelines in this area.
基金Under the auscpices of Shandong Provincial Natural Science Foundation (No.ZR2020QD090)Research Funds of Beijing VMinFull Limted (No.VMF2021RS)+1 种基金National Natural Science Foundation of China (No.42176221)Seed Project of Yantai Institute of Coastal Zone Research,Chinese Academy of Sciences (No.YICE351030601)。
文摘With the loss of substantial natural wetlands in coastal zones,artificial wetlands provide alternative habitats for many shorebirds.Scientific management of artificial wetlands used by shorebirds plays an important role in maintaining the stability of shorebird population.Satellite tracking technique can obtain high-precision location information of individuals day and night,providing a good technical support for the study of quantitative relationship between waterfowls and their habitats.In this study,satellite tracking method,Remote Sensing(RS)and Geographic Information System(GIS)technology were used to analyze the activity pattern and habitat utilization characteristics of Pied Avocet during breeding period in an artificial wetland complex in the Yellow River Delta(YRD),China.The results showed that the breeding Pied Avocets had a small range of activity,with a total core and main home range of 33.10 km^(2) and 216.30 km^(2),respectively.This species tended to forage in the pond and salt pan during the day and night,respectively,with an unfixed staying time in the breeding ground.The distance between breeding ground and feeding ground was less than 6 km.It is emphasized that in addition to improving the conditions of the remaining natural habitats,effective managing artificial habitats is a priority for shorebird conservation.This research could provide reference for the management of artificial wetlands in coastal zones and supply technique support for the protection of shorebirds and their habitats,and alleviate human-bird conflicts and sustainable development of coastal zones.
基金The Petrochina Basic Prospective Science and Technology Research Project–Overseas deepwater ultra-deepwater oil and gas exploration technology research topic,under contract No.2021DJ2403。
文摘The Zambezi Delta basin is a passive marginal basin located on the East African coast that has good oil and gas exploration potential.Due to the special geological evolutionary background of the Beira High in the Zambezi Delta basin,it has a low gravity anomaly,and the existing seismic survey lines do not cover the whole basin;therefore,it is difficult to interpret the structural characteristics of the whole basin based solely on gravity or seismic data.Based on satellite altimetry gravity anomaly data,this study infers the distribution characteristics of faults in the Zambezi Delta basin by using the normalized vertical derivative of the total horizontal derivative(NVDR-THDR)technique.Then,constrained by seismic data,the gravity anomaly at the Moho interface is extracted by using the fast forward method of the double-interface model of the gravity anomaly,and this anomaly is then removed from the Bouguer gravity anomaly to obtain the sedimentary layer gravity anomaly.The thickness of the sedimentary strata is obtained by inversing the sedimentary basement depth of the whole basin.Then,uplifts and depressions are divided based on a sedimentary layer thickness of 3 km.This research demonstrates that the Zambezi Delta basin mainly features nearly SN-trending and NE-trending faults and that these faults exhibit east-west partitioning.The nearly SN-trending strike-slip faults controlled the sedimentary development of the basin,and the NE-trending tensile faults may have acted as migration channels for oil,gas and magma.The“overcompensation”effect of the Moho interface gravity anomaly on the gravity anomaly of the sedimentary layer is caused by the depression of the Moho interface beneath the Beira High,which results in a low gravity anomaly value for the Beira High.The pattern of uplifts and depressions trends NE and has the structural characteristics of east-west blocks.
文摘Based on the supply-side perspective,the improved STIRPAT model is applied to reveal the mechanisms of supply-side factors such as human,capital,technology,industrial synergy,institutions and economic growth on carbon emissions in the Yangtze River Delta(YRD)through path analysis,and to forecast carbon emissions in the YRD from the baseline scenario,factor regulation scenario and integrated scenario to reach the peak.The results show that:(1)Jiangsu's high carbon emission pattern is the main reason for the YRD hindering the synergistic regulation of carbon emissions.(2)Human factors,institutional factors and economic growth factors can all contribute to carbon emissions in the YRD region,while technological and industrial factors can generally suppress carbon emissions in the YRD region.(3)Under the capital regulation scenario,the YRD region has the highest level of carbon emission synergy,with Jiangsu reaching its peak five years earlier.Under the balanced regulation scenario,the YRD region as a whole,Jiangsu,Zhejiang and Anhui reach the peak as scheduled.
基金Supported by the CNOOC Technology Research Project(KJGG2022-0102)。
文摘Based on the 3D seismic data and the analysis and test data of lithology,electricity,thin sections and chronology obtained from drilling of the Qiongdongnan Basin,the characteristics and the quantitative analysis of the source-sink system are studied of the third member of the Upper Oligocene Lingshui Formation(Ling 3 Member)in the southern fault step zone of the Baodao Sag.First,the YL10 denudation area of the Ling 3 Member mainly developed two fluvial systems in the east and west,resulting in the formation of two dominant sand transport channels and two delta lobes in southern Baodao Sag,which are generally large in the west and small in the east.The evolution of the delta has experienced four stages:initiation,prosperity,intermittence and rejuvenation.Second,the source-sink coupled quantitative calculation is performed depending on the parameters of the delta sand bodies,including development phases,distribution area,flattening thickness,area of different parent rocks,and sand-forming coefficient,showing that the study area has the material basis for the formation of large-scale reservoir.Third,the drilling reveals that the delta of the Ling 3 Member is dominated by fine sandstone,with total sandstone thickness of 109-138 m,maximum single-layer sandstone thickness of 15.5-30.0 m,and sand-to-strata ratio of 43.7%-73.0%,but the physical properties are different among the fault steps.Fourth,the large delta development model of the small source area in the step fault zone with multi-stage uplift is established.It suggests that the episodic uplift provides sufficient sediments,the fluvial system and watershed area control the scale of the sand body,the multi-step active fault steps dominate the sand body transport channel,and local fault troughs decide the lateral propulsion direction of the sand body.The delta of the Ling 3 Member is coupled with fault blocks to form diverse traps,which are critical exploration targets in southern Baodao Sag.
基金financially supported by the National Natural Science Foundation of China (Grant No. 41461011)。
文摘The Yellow River Delta(YRD), a critical economic zone along China's eastern coast, also functions as a vital ecological reserve in the lower Yellow River. Amidst rapid industrialization and urbanization, the region has witnessed significant land use/cover changes(LUCC), impacting ecosystem services(ES) and ecological security patterns(ESP). Investigating LUCC's effects on ES and ESP in the YRD is crucial for ecological security and sustainable development. This study utilized the PLUS model to simulate 2030 land use scenarios, including natural development(NDS), economic development(EDS), and ecological protection scenarios(EPS). Subsequently, the InVEST model and circuit theory were applied to assess ES and ESP under varying LUCC scenarios from 2010 to 2030. Findings indicate:(1) Notable LUCC from 2010 to 2030, marked by decreasing cropland and increasing construction land and water bodies.(2) From 2010 to 2020, improvements were observed in carbon storage,water yield, soil retention, and habitat quality, whereas 2020–2030 saw increases in water yield and soil retention but declines in habitat quality and carbon storage. Among the scenarios, EPS showed superior performance in all four ES.(3) Between 2010 and 2030, ecological sources, corridors, and pinchpoints expanded, displaying significant spatial heterogeneity. The EPS scenario yielded the most substantial increases in ecological sources,corridors, and pinchpoints, totaling 582.89 km^(2), 645.03 km^(2),and 64.43 km^(2), respectively. This study highlights the importance of EPS, offering insightful scientific guidance for the YRD's sustainable development.
文摘BACKGROUND The coronavirus disease 2019(COVID-19)virus has been a world-known pan-demic since February 2020.Multiple variances had been established;the most common variants in Israel were omicron and delta.AIM To analyze and compare laboratory values in the"omicron"and"delta"variants of the coronavirus by conducting follow-up examinations and laboratory audits on COVID-19 patients admitted to our institution.METHODS A retrospective study,two groups,50 patients in each group.Patients examined positive for COVID-19 were divided into groups according to the common variant at the given time.We reviewed demographic data and laboratory results such as complete blood count and full chemistry,including electrolytes and coagulation parameters.RESULTS The mean age was 52%,66.53±21.7 were female.No significance was found comparing laboratory results in the following disciplines:Blood count,hemo-globin,and lymphocytes(P=0.41,P=0.87,P=0.97).Omicron and delta variants have higher neutrophil counts,though they are not significantly different(P=0.38).Coagulation tests:Activated paritial thromoplastin test and international normalized ratio(P=0.72,P=0.68).We found no significance of abnormality for all electrolytes.CONCLUSION The study compares laboratory results of blood tests between two variants of the COVID-19 virus–omicron and delta.We found no significance between the variants.Our results show the need for further research with larger data as well as the need to compare all COVID-19 variants.