Objective:?To indentify Optimal cutoffs of grip strength for definition as weakness in the elderly. Methods: Our study population comprised 1317 subjects (mean ± SD age: 67.6 ± 6.0 years;44.3% men) from the ...Objective:?To indentify Optimal cutoffs of grip strength for definition as weakness in the elderly. Methods: Our study population comprised 1317 subjects (mean ± SD age: 67.6 ± 6.0 years;44.3% men) from the Hangu area of Tianjin, China. Data collection includes general physical examination, biochemical indicators and questionnaire. Mobility limitation was defined as a 4-m walking speed < 0.8 m/s and grip strength represents muscle strength. According to the ROC curve model, the cut-off point of grip strength was calculated, when mobility limitation was selected as the target variables. Results: According to the results of ROC curve, In man, grip strength is lower than 32.45 kg, the strength is weaker, Sensitivity is 79.7% and Specificity is 64.9%, the AUC is 0.764 (p < 0.001);In women, grip strength is lower than 18.20 kg, the strength is weaker, Sensitivity is 53.3% and Specificity is78.1%, the AUC is 0.703 (p < 0.001). Conclusions: Cut points for weakness derived from this large, diverse sample of older adults may be useful to identify populations who may benefit from interventions to improve muscle strength and function.展开更多
Methodologies have been developed for calculating cutoffs of reservoir intervals with production capacity （RIPC） and reservoir intervals with accumulation capacity （RIAC） according to the types of pore throat stru...Methodologies have been developed for calculating cutoffs of reservoir intervals with production capacity （RIPC） and reservoir intervals with accumulation capacity （RIAC） according to the types of pore throat structures and dynamic force by using data from petrophysical analysis, production tests and mercury injection. The data are from clastic reservoirs in the third member （Es3） and the fourth member （Es4） of the Shahejie Formation in the Shengtuo area on the North Slope of the Dongying Sag, Jiyang Depression, China. The method of calculating cutoffs of RIPC is summarized as follows： 1） determination of permeability cutoffs of RIPC; 2） classification of types of pore-throat structures according to mercury injection data and then relating porosity to permeability and determining the relationship between porosity and permeability according to each type of pore-throat structure; and 3） calculating porosity cutoffs of RIPC using established correlation between porosity and permeability according to the type of pore throat structure. The method of calculating cutoffs of RIAC includes： 1） establishing a functional relationship between oil-water interracial tension and formation temperature; 2） calculating limiting values of maximum connected pore-throat radii according to formation temperature and dynamic forces of each reservoir interval; 3） correlating permeability with maximum connected pore-throat radius and then obtaining permeability cutoffs of RIAC; and 4） calculating porosity cutoffs on the basis of permeability cutoffs according to specific correlations, suitable for the type of porethroat structure. The results of this study show that porosity and permeability cutoffs of clastic reservoirs decrease with depth. For a fixed permeability cutoff, the porosity cutoff of R1PC varies because the type of pore throat is different. At a fixed temperature, porosity and permeability cutoffs of RIAC decrease as dynamic force increases. For a fixed permeability cutoff of effective hydrocarbon accumulation, the porosity cutoff also varies with different types of pore throat.展开更多
Surface mining operations play a crucial role in meeting the world’s increasing demand for mineral resources for the advancement of technology and debauched expansion of economies. The search for and exploitation of ...Surface mining operations play a crucial role in meeting the world’s increasing demand for mineral resources for the advancement of technology and debauched expansion of economies. The search for and exploitation of these mineral resources are therefore important for the sustainability of the mineral extraction industry. To this end, efficient mine planning must incorporate sterilisation drilling and effective waste rock management principles in the search and exploitation of these minerals. In this article, sterilisation drilling is being reviewed vis-a-vis the establishment of waste and tailings dump locations, backfilling of open pit excavations and mine closure giving critical attention to the minerals and mining laws of Ghana. Subsequently, a detailed case study of a surface mining operation that successfully incorporated sterilisation drilling in determining waste dump location in its mine planning process has been presented in this study. The findings indicate that the proposed waste dump location could present a potential mining prospect in the future based on enhanced milling capacity/technology and improved mineral commodity price;underscoring the significance of sterilization drilling in the sustainability of the mining industry.展开更多
Tight sandstone reservoirs are generally characterized by complex reservoir quality,non-Darcy flow,and strong heterogeneity.Approaches utilized for evaluating physical property cutoffs of conventional reservoirs maybe...Tight sandstone reservoirs are generally characterized by complex reservoir quality,non-Darcy flow,and strong heterogeneity.Approaches utilized for evaluating physical property cutoffs of conventional reservoirs maybe inapplicable.Thus,a comprehensive investigation on physical property cutoffs of tight sandstone reservoirs is crucial for the reserve evaluation and successful exploration.In this study,a set of evaluation approaches take advantage of field operations(i.e.,core drilling,oil testing,and wireline well logging data),and simulation experiments(i.e.,high-pressure mercury injection-capillary pressure(MICP)experiment,oil-water relative permeability experiment,nuclear magnetic resonance(NMR)experiment,and biaxial pressure simulation experiment)were comparatively optimized to determine the physical property cutoffs of effective reservoirs in the Upper Triassic Chang 6,Chang 8 and Chang 9 oil layers of the Zhenjing Block.The results show that the porosity cutoffs of the Chang 6,Chang 8,and Chang 9 oil layers are 7.9%,6.4%,and 8.6%,and the corresponding permeability are 0.08 mD,0.05 mD,and 0.09 mD,respectively.Coupled with wireline well logging,mud logging,and oil testing,the cut-off of the thickness of single-layer effective reservoirs are approximately 3.0 m,3.0 m,and 2.0 m,respectively.Depending on the cutoffs of critical properties,a superimposed map showing the planar distribution of the prospective targets can be mapped,which may delineate the effective boundary of prospective targets for petroleum exploration of tight sandstone reservoirs.展开更多
The experimental research programs of 1950s, to understand the adsorption of CO on W surfaces, changed to ab initio studies in 2000s. The goals were to seek improved practical applications. Most of the studies were ba...The experimental research programs of 1950s, to understand the adsorption of CO on W surfaces, changed to ab initio studies in 2000s. The goals were to seek improved practical applications. Most of the studies were based on density functional theory. Many studies also used programs, such as VASP (Vienna Abinitio simulation package) and CPMD. The computational procedures used plane wave approximations. This needed studies with selection of K points and cutoff energy selection to assure convergence in energy calculations. Observations and analysis of papers published from 2006 to 2022 indicate that the cutoff energies were selected arbitrarily without any needed convergence studies. By selecting a published 2006 paper, this paper has clearly showed that an arbitrary selection of cutoff energy, such as 460 eV, is not in the range of, cutoff energies that assure convergence of energy calculations, with ab initio methods and have indicated correction procedures. .展开更多
Synthetic aperture radars(SARs)encounter the azimuth cutoff problem when observing sea waves.Consequently,SARs can only capture the waves with wavelengths larger than the cutoff wavelength and lose the information of ...Synthetic aperture radars(SARs)encounter the azimuth cutoff problem when observing sea waves.Consequently,SARs can only capture the waves with wavelengths larger than the cutoff wavelength and lose the information of waves with smaller wavelengths.To increase the accuracy of SAR wave observations,this paper investigates an azimuth cutoff compensation method based on the simulated multiview SAR wave synchronization data obtained by the collaborative observation via networked satellites.Based on the simulated data and the equivalent multiview measured data from Sentinel-1 virtual networking,the method is verified and the cutoff wavelengths decrease by 16.40%and 14.00%.The biases of the inversion significant wave height with true values decrease by 0.04 m and 0.14 m,and the biases of the mean wave period decrease by 0.17 s and 0.22 s,respectively.These results demonstrate the effectiveness of the azimuth cutoff compensation method.Based on the azimuth cutoff compensation method,the multisatellite SAR networking mode for wave observations are discussed.The highest compensation effect is obtained when the combination of azimuth angle is(95°,115°,135°),the orbital intersection angle is(50°,50°),and three or four satellites are used.The study of the multisatellite networking mode in this paper can provide valuable references for the compensation of azimuth cutoff and the observation of waves by a multisatellite network.展开更多
Objective:To surveill emerging variants by nanopore technology-based genome sequencing in different COVID-19 waves in Sri Lanka and to examine the association with the sample characteristics,and vaccination status.Met...Objective:To surveill emerging variants by nanopore technology-based genome sequencing in different COVID-19 waves in Sri Lanka and to examine the association with the sample characteristics,and vaccination status.Methods:The study analyzed 207 RNA positive swab samples received to sequence laboratory during different waves.The N gene cut-off threshold of less than 30 was considered as the major inclusion criteria.Viral RNA was extracted,and elutes were subjected to nanopore sequencing.All the sequencing data were uploaded in the publicly accessible database,GISAID.Results:The Omicron,Delta and Alpha variants accounted for 58%,22%and 4%of the variants throughout the period.Less than 1%were Kappa variant and 16%of the study samples remained unassigned.Omicron variant was circulated among all age groups and in all the provinces.Ct value and variants assigned percentage was 100%in Ct values of 10-15 while only 45%assigned Ct value over 25.Conclusions:The present study examined the emergence,prevalence,and distribution of SARS-CoV-2 variants locally and has shown that nanopore technology-based genome sequencing enables whole genome sequencing in a low resource setting country.展开更多
文摘Objective:?To indentify Optimal cutoffs of grip strength for definition as weakness in the elderly. Methods: Our study population comprised 1317 subjects (mean ± SD age: 67.6 ± 6.0 years;44.3% men) from the Hangu area of Tianjin, China. Data collection includes general physical examination, biochemical indicators and questionnaire. Mobility limitation was defined as a 4-m walking speed < 0.8 m/s and grip strength represents muscle strength. According to the ROC curve model, the cut-off point of grip strength was calculated, when mobility limitation was selected as the target variables. Results: According to the results of ROC curve, In man, grip strength is lower than 32.45 kg, the strength is weaker, Sensitivity is 79.7% and Specificity is 64.9%, the AUC is 0.764 (p < 0.001);In women, grip strength is lower than 18.20 kg, the strength is weaker, Sensitivity is 53.3% and Specificity is78.1%, the AUC is 0.703 (p < 0.001). Conclusions: Cut points for weakness derived from this large, diverse sample of older adults may be useful to identify populations who may benefit from interventions to improve muscle strength and function.
基金co-funded by National Natura Science Foundation of China (Grant No. 41102058 Gran No. U1262203)+4 种基金the National Science and Technology Special Grant (No. 2011ZX05006-003)Shandong Natura Science Foundation (Grant No. ZR2011DQ017)the Fundamental Research Funds for the Central Universities (No. 12CX04001A No. 13CX02035A No. 13CX02036A)
文摘Methodologies have been developed for calculating cutoffs of reservoir intervals with production capacity （RIPC） and reservoir intervals with accumulation capacity （RIAC） according to the types of pore throat structures and dynamic force by using data from petrophysical analysis, production tests and mercury injection. The data are from clastic reservoirs in the third member （Es3） and the fourth member （Es4） of the Shahejie Formation in the Shengtuo area on the North Slope of the Dongying Sag, Jiyang Depression, China. The method of calculating cutoffs of RIPC is summarized as follows： 1） determination of permeability cutoffs of RIPC; 2） classification of types of pore-throat structures according to mercury injection data and then relating porosity to permeability and determining the relationship between porosity and permeability according to each type of pore-throat structure; and 3） calculating porosity cutoffs of RIPC using established correlation between porosity and permeability according to the type of pore throat structure. The method of calculating cutoffs of RIAC includes： 1） establishing a functional relationship between oil-water interracial tension and formation temperature; 2） calculating limiting values of maximum connected pore-throat radii according to formation temperature and dynamic forces of each reservoir interval; 3） correlating permeability with maximum connected pore-throat radius and then obtaining permeability cutoffs of RIAC; and 4） calculating porosity cutoffs on the basis of permeability cutoffs according to specific correlations, suitable for the type of porethroat structure. The results of this study show that porosity and permeability cutoffs of clastic reservoirs decrease with depth. For a fixed permeability cutoff, the porosity cutoff of R1PC varies because the type of pore throat is different. At a fixed temperature, porosity and permeability cutoffs of RIAC decrease as dynamic force increases. For a fixed permeability cutoff of effective hydrocarbon accumulation, the porosity cutoff also varies with different types of pore throat.
文摘Surface mining operations play a crucial role in meeting the world’s increasing demand for mineral resources for the advancement of technology and debauched expansion of economies. The search for and exploitation of these mineral resources are therefore important for the sustainability of the mineral extraction industry. To this end, efficient mine planning must incorporate sterilisation drilling and effective waste rock management principles in the search and exploitation of these minerals. In this article, sterilisation drilling is being reviewed vis-a-vis the establishment of waste and tailings dump locations, backfilling of open pit excavations and mine closure giving critical attention to the minerals and mining laws of Ghana. Subsequently, a detailed case study of a surface mining operation that successfully incorporated sterilisation drilling in determining waste dump location in its mine planning process has been presented in this study. The findings indicate that the proposed waste dump location could present a potential mining prospect in the future based on enhanced milling capacity/technology and improved mineral commodity price;underscoring the significance of sterilization drilling in the sustainability of the mining industry.
基金supported by the National Natural Science Foundation of China(Grant Nos.42072172 and 41772120)the Shandong Province Natural Science Fund for Distinguished Young Scholars(No.JQ201311)the Graduate Scientific and Technological Innovation Project Financially Supported by Shandong University of Science and Technology(No.SDKDYC190313)。
文摘Tight sandstone reservoirs are generally characterized by complex reservoir quality,non-Darcy flow,and strong heterogeneity.Approaches utilized for evaluating physical property cutoffs of conventional reservoirs maybe inapplicable.Thus,a comprehensive investigation on physical property cutoffs of tight sandstone reservoirs is crucial for the reserve evaluation and successful exploration.In this study,a set of evaluation approaches take advantage of field operations(i.e.,core drilling,oil testing,and wireline well logging data),and simulation experiments(i.e.,high-pressure mercury injection-capillary pressure(MICP)experiment,oil-water relative permeability experiment,nuclear magnetic resonance(NMR)experiment,and biaxial pressure simulation experiment)were comparatively optimized to determine the physical property cutoffs of effective reservoirs in the Upper Triassic Chang 6,Chang 8 and Chang 9 oil layers of the Zhenjing Block.The results show that the porosity cutoffs of the Chang 6,Chang 8,and Chang 9 oil layers are 7.9%,6.4%,and 8.6%,and the corresponding permeability are 0.08 mD,0.05 mD,and 0.09 mD,respectively.Coupled with wireline well logging,mud logging,and oil testing,the cut-off of the thickness of single-layer effective reservoirs are approximately 3.0 m,3.0 m,and 2.0 m,respectively.Depending on the cutoffs of critical properties,a superimposed map showing the planar distribution of the prospective targets can be mapped,which may delineate the effective boundary of prospective targets for petroleum exploration of tight sandstone reservoirs.
文摘The experimental research programs of 1950s, to understand the adsorption of CO on W surfaces, changed to ab initio studies in 2000s. The goals were to seek improved practical applications. Most of the studies were based on density functional theory. Many studies also used programs, such as VASP (Vienna Abinitio simulation package) and CPMD. The computational procedures used plane wave approximations. This needed studies with selection of K points and cutoff energy selection to assure convergence in energy calculations. Observations and analysis of papers published from 2006 to 2022 indicate that the cutoff energies were selected arbitrarily without any needed convergence studies. By selecting a published 2006 paper, this paper has clearly showed that an arbitrary selection of cutoff energy, such as 460 eV, is not in the range of, cutoff energies that assure convergence of energy calculations, with ab initio methods and have indicated correction procedures. .
基金the support of the National Natural Science Foundation of China(No.61931025)the National Key R&D Program of China(No.2017YFC1405600)。
文摘Synthetic aperture radars(SARs)encounter the azimuth cutoff problem when observing sea waves.Consequently,SARs can only capture the waves with wavelengths larger than the cutoff wavelength and lose the information of waves with smaller wavelengths.To increase the accuracy of SAR wave observations,this paper investigates an azimuth cutoff compensation method based on the simulated multiview SAR wave synchronization data obtained by the collaborative observation via networked satellites.Based on the simulated data and the equivalent multiview measured data from Sentinel-1 virtual networking,the method is verified and the cutoff wavelengths decrease by 16.40%and 14.00%.The biases of the inversion significant wave height with true values decrease by 0.04 m and 0.14 m,and the biases of the mean wave period decrease by 0.17 s and 0.22 s,respectively.These results demonstrate the effectiveness of the azimuth cutoff compensation method.Based on the azimuth cutoff compensation method,the multisatellite SAR networking mode for wave observations are discussed.The highest compensation effect is obtained when the combination of azimuth angle is(95°,115°,135°),the orbital intersection angle is(50°,50°),and three or four satellites are used.The study of the multisatellite networking mode in this paper can provide valuable references for the compensation of azimuth cutoff and the observation of waves by a multisatellite network.
文摘Objective:To surveill emerging variants by nanopore technology-based genome sequencing in different COVID-19 waves in Sri Lanka and to examine the association with the sample characteristics,and vaccination status.Methods:The study analyzed 207 RNA positive swab samples received to sequence laboratory during different waves.The N gene cut-off threshold of less than 30 was considered as the major inclusion criteria.Viral RNA was extracted,and elutes were subjected to nanopore sequencing.All the sequencing data were uploaded in the publicly accessible database,GISAID.Results:The Omicron,Delta and Alpha variants accounted for 58%,22%and 4%of the variants throughout the period.Less than 1%were Kappa variant and 16%of the study samples remained unassigned.Omicron variant was circulated among all age groups and in all the provinces.Ct value and variants assigned percentage was 100%in Ct values of 10-15 while only 45%assigned Ct value over 25.Conclusions:The present study examined the emergence,prevalence,and distribution of SARS-CoV-2 variants locally and has shown that nanopore technology-based genome sequencing enables whole genome sequencing in a low resource setting country.
