The paper establishes a theorem of data perturbation analysis for the support vector classifier dual problem, from which the data perturbation analysis of the corresponding primary problem may be performed through sta...The paper establishes a theorem of data perturbation analysis for the support vector classifier dual problem, from which the data perturbation analysis of the corresponding primary problem may be performed through standard results. This theorem derives the partial derivatives of the optimal solution and its corresponding optimal decision function with respect to data parameters, and provides the basis of quantitative analysis of the influence of data errors on the optimal solution and its corresponding optimal decision function. The theorem provides the foundation for analyzing the stability and sensitivity of the support vector classifier.展开更多
The existing literature on audit opinion shopping provides inconsistent evidence on whether such shopping has any association with abnormal audit fees. In this paper, we hypothesize that firms engage in audit opinion ...The existing literature on audit opinion shopping provides inconsistent evidence on whether such shopping has any association with abnormal audit fees. In this paper, we hypothesize that firms engage in audit opinion shopping and pay an abnormal audit fee only when their degree of accounting quality is low. To examine the issue, we group firms on the basis of their change in return on assets(ROA), and show that abnormal audit fees improve audit opinions only among firms that engage local auditors and have a low degree of ROA, but report a large increase in ROA, especially when the ROA change is the result of abnormal accruals. We find no association between abnormal audit fees and audit opinion improvement for other firms.展开更多
Do supply chain audits have real effects?We focus on the effect of shared auditors in the supply chain on corporate cost stickiness.When a supplier shares auditors with its customers,the shared auditors provide inform...Do supply chain audits have real effects?We focus on the effect of shared auditors in the supply chain on corporate cost stickiness.When a supplier shares auditors with its customers,the shared auditors provide informational advantages for suppliers’managers,thus revising their optimistic or pessimistic expectations and influencing suppliers’cost stickiness.Using a sample of Chinese A-share listed companies from 2009 to 2017,we explore the relationship between shared auditors and suppliers’cost stickiness conditional on management expectations.The results show that shared auditors in the supply chain reduce suppliers’cost stickiness significantly when suppliers’managers hold optimistic expectations,and increase suppliers’cost stickiness in cases of pessimistic expectations.Furthermore,the greater the number of shared auditors,the stronger the effect.Such effects are more pronounced when supplier firms share auditors with important customers,have higher demand uncertainty,and use big 10 auditors.展开更多
Bimetallic Fe-Co/GAC (granular activated carbon) was prepared and used as heterogeneous catalyst in the ultrasound enhanced heterogeneous activation of peroxydisulfate (PS, S2O8 2-) process. The effect of initial ...Bimetallic Fe-Co/GAC (granular activated carbon) was prepared and used as heterogeneous catalyst in the ultrasound enhanced heterogeneous activation of peroxydisulfate (PS, S2O8 2-) process. The effect of initial pH, PS concentration, catalyst addition and stirring rate on the decolorization of Acid Orange 7 (AO7) was investigated. The results showed that the decolorization efficiency increased with an increase in PS concentration from 0.3 to 0.5 g/L and an increase in catalyst amount from 0.5 to 0.8 g/L. But further increase in PS concentration and catalyst addition would result in an unpronounced increase in decolorization efficiency. In the range of 300 to 900 r/min, stirring rate had little effect on AO7 decolorization. The catalyst stability was evaluated by measuring decolorization efficiency for four successive cycles.展开更多
This cross-sectional study aimed to investigate the quality of care of diabetes in Shanghai,China.A total of 173235 patients with type 2 diabetes in 2017 were included in the analysis.Profiles of risk factors and inte...This cross-sectional study aimed to investigate the quality of care of diabetes in Shanghai,China.A total of 173235 patients with type 2 diabetes in 2017 were included in the analysis.Profiles of risk factors and intermediate outcomes were determined.The patients had a mean age of 66.43±8.12(standard deviation(SD))years and a mean diabetes duration of 7.95±5.53(SD)years.The percentage of patients who achieved the target level for HbA_(1c)(<7.0%)was 48.6%.Patients who achieved the target levels for blood pressure(BP)<130/80 mmHg and low-density lipoprotein-cholesterol(LDL-c)<2.6 mmol/L reached 17.5%and 34.0%,respectively.A total of 3.8%achieved all three target levels,and the value increased to 6.8%with an adaptation of the BP target level(<140/90 mmHg)for those over 65 years.Multivariable analysis identified the factors associated with a great likelihood of achieving all three target levels:male,young age,short diabetes duration,low body mass index,macrovascular complications,no microvascular complications,prescribed with lipid-lowering medication,and no prescription of antihypertensive medication.In conclusion,nearly 50%and one-third of the patients with diabetes met the target levels for HbA_(1c)and LDL-c,respectively,with a low percentage achieving the BP target level.The percentage of patients who achieved all three target levels needs significant improvement.展开更多
The significant increase of NO_(x)concentration causes severe damages to environment and human health.Light-driven photocatalytic technique affords an ideal solution for the removal of NO_(x)at ambient conditions.To e...The significant increase of NO_(x)concentration causes severe damages to environment and human health.Light-driven photocatalytic technique affords an ideal solution for the removal of NO_(x)at ambient conditions.To enhance the performance of NO_(x)removal,1D,2D and 3D photocatalysts have been constructed as the light absorption and the separation of charge carriers can be manipulated through controlling the morphology of the photocatalyst.Related works mainly focused on the construction and modification of special morphologic photocatalyst,including element doping,heterostructure constructing,crystal facet exposing,defect sites introducing and so on.Moreover,the excellent performance of the photocatalytic NO_(x)removal creates great awareness of the application,which has promising practical applications in NO_(x)removal by paint(removing NO_(x)indoor and outdoor)and pavement(degrading vehicle exhausts).For these considerations,recent advances in special morphologic photocatalysts for NO_(x)removal was summarized and commented in this review.The purpose is to provide insights into understanding the relationship between morphology and photocatalytic performance,meanwhile,to promote the application of photocatalytic technology in NO_(x)degradation.展开更多
Organosilicon compounds play an important role in the fields of materials science,pharmacy,and organic synthesis.The development of effective approaches for the preparation of these compounds have also become a resear...Organosilicon compounds play an important role in the fields of materials science,pharmacy,and organic synthesis.The development of effective approaches for the preparation of these compounds have also become a research focus in organic synthesis.In recent years,free radical synthesis of organosilicons has been vigorously developed,which generally has the advantages of milder synthesis conditions,higher yields and selectivity,and free of precious metal catalysts compared with traditional strategies.This article reviews research progresses in the synthesis of organosilico n compounds by free radical pathways since 2016.In most cases,the radical silylation is achieved based on the reaction of silyl radicals,which are triggered by four routes including peroxide,transition-metal-induced peroxide decomposition,alkali,photocatalysis.The alkyl radicals can also initiate the radical silylation for the generation of C(sp^(3))—Si bonds.展开更多
Iodine catalyzed one-pot reactions of salicylaldehyde and dimolecular 1H-indene-l,3(2H)-dione, barbituric acids, 4-hydro- xycoumarin, or 4-hydroxy-6-methylpyran-2-one were performed and provided a rapid, convenient ...Iodine catalyzed one-pot reactions of salicylaldehyde and dimolecular 1H-indene-l,3(2H)-dione, barbituric acids, 4-hydro- xycoumarin, or 4-hydroxy-6-methylpyran-2-one were performed and provided a rapid, convenient and general approach to synthesize the chromene derivatives. 2-(11-Oxo-10,11-dihydroindeno[1,2-b]chromen-10-yl)-lH-indene-1,3(2H)-diones P1-P4 and 10-(4-hydroxy-6-methyl-2-oxo-2H-pyran-3-yl)-3-methylpyrano[4,3-b]chromen-1(1OH)-ones P8-P9 were unprecedentedly prepared and structurally identified by NMR and Mass. The confirmation of structure by single crystal X-ray crystallography is reported for P3.展开更多
Catalytic hydrodeoxygenation(HDO)is one of the most effective methods to upgrade the oxygen-containing compounds derived from coal tar to valuable hydrocarbons.Herein,an efficient bimetallic catalyst Pt_(1)Ni_(4)/MgO ...Catalytic hydrodeoxygenation(HDO)is one of the most effective methods to upgrade the oxygen-containing compounds derived from coal tar to valuable hydrocarbons.Herein,an efficient bimetallic catalyst Pt_(1)Ni_(4)/MgO was prepared and applied in the HDO of dibenzofuran(DBF).High yield(95%)of the desired product bicyclohexane(BCH)was achieved at 240℃and 1.2 MPa of H_(2).Superior catalytic performance could be ascribed to the"relay catalysis"of Pt sites and Ni sites,and the reaction pathway is proposed as well.Scale-up experiment and recyclability test were also performed,which demonstrated the recyclability and promising potential application of Pt_(1)Ni_(4)/MgO.展开更多
A convenient method for Morita-Baylis-Hillman reaction of arylaldehydes with methyl acrylate has been developed by using fluorous-tag organocatalyst 1-[4-(perfluorooctyl)phenyl]-3-phenylthiourea and DABCO at room te...A convenient method for Morita-Baylis-Hillman reaction of arylaldehydes with methyl acrylate has been developed by using fluorous-tag organocatalyst 1-[4-(perfluorooctyl)phenyl]-3-phenylthiourea and DABCO at room temperature. The fluorous organocatalyst could be recovered from the reaction mixture by fluorous solid-phase extraction (F-SPE) with excellent purity for direct reuse.展开更多
The macroeconomic policy environment affects the internal governance of microenterprises,which may provide opportunities for management to benefit from stock sales while decreasing its motivation to manipulate stock t...The macroeconomic policy environment affects the internal governance of microenterprises,which may provide opportunities for management to benefit from stock sales while decreasing its motivation to manipulate stock transactions.Using a sample of Chinese A-share listed companies from 2007 to2018,we study the impact of macroeconomic policy uncertainty on opportunistic insider trading.The results show that macroeconomic policy uncertainty helps restrain the opportunistic trading of shares held by management.When macroeconomic policies are uncertain,enterprises improve their internal governance.Furthermore,strengthening equity governance helps reduce management’s opportunistic use of the uncertainty of the policy environment,highlighting the advantageous effect of macroeconomic policy uncertainty and helping regulators standardize managerial behavior and promote the governance effect of macroeconomic policy.展开更多
文摘The paper establishes a theorem of data perturbation analysis for the support vector classifier dual problem, from which the data perturbation analysis of the corresponding primary problem may be performed through standard results. This theorem derives the partial derivatives of the optimal solution and its corresponding optimal decision function with respect to data parameters, and provides the basis of quantitative analysis of the influence of data errors on the optimal solution and its corresponding optimal decision function. The theorem provides the foundation for analyzing the stability and sensitivity of the support vector classifier.
文摘The existing literature on audit opinion shopping provides inconsistent evidence on whether such shopping has any association with abnormal audit fees. In this paper, we hypothesize that firms engage in audit opinion shopping and pay an abnormal audit fee only when their degree of accounting quality is low. To examine the issue, we group firms on the basis of their change in return on assets(ROA), and show that abnormal audit fees improve audit opinions only among firms that engage local auditors and have a low degree of ROA, but report a large increase in ROA, especially when the ROA change is the result of abnormal accruals. We find no association between abnormal audit fees and audit opinion improvement for other firms.
基金the National Social Science Foundation of China(Major Project 13&ZD146)the Fundamental Research Funds for the Central Universities of China(No.JBK19072018153)for their support.
文摘Do supply chain audits have real effects?We focus on the effect of shared auditors in the supply chain on corporate cost stickiness.When a supplier shares auditors with its customers,the shared auditors provide informational advantages for suppliers’managers,thus revising their optimistic or pessimistic expectations and influencing suppliers’cost stickiness.Using a sample of Chinese A-share listed companies from 2009 to 2017,we explore the relationship between shared auditors and suppliers’cost stickiness conditional on management expectations.The results show that shared auditors in the supply chain reduce suppliers’cost stickiness significantly when suppliers’managers hold optimistic expectations,and increase suppliers’cost stickiness in cases of pessimistic expectations.Furthermore,the greater the number of shared auditors,the stronger the effect.Such effects are more pronounced when supplier firms share auditors with important customers,have higher demand uncertainty,and use big 10 auditors.
基金supported by the National Natural Science Foundation of China (No. 20977069, 21211130108)the Natural Science Foundation of Hubei Province, China through "The Outstanding Youth Scholars Program" (No. 2007ABB028)
文摘Bimetallic Fe-Co/GAC (granular activated carbon) was prepared and used as heterogeneous catalyst in the ultrasound enhanced heterogeneous activation of peroxydisulfate (PS, S2O8 2-) process. The effect of initial pH, PS concentration, catalyst addition and stirring rate on the decolorization of Acid Orange 7 (AO7) was investigated. The results showed that the decolorization efficiency increased with an increase in PS concentration from 0.3 to 0.5 g/L and an increase in catalyst amount from 0.5 to 0.8 g/L. But further increase in PS concentration and catalyst addition would result in an unpronounced increase in decolorization efficiency. In the range of 300 to 900 r/min, stirring rate had little effect on AO7 decolorization. The catalyst stability was evaluated by measuring decolorization efficiency for four successive cycles.
基金supported by the Shanghai Municipal Government Grants Award(No.GWIV-3)the Shanghai Health Policy Grant(No.2019HP49)+3 种基金the Shanghai Health Commission Grant(No.20194Y0141)the Shanghai Jiao Tong University Grant(No.CHDI-2018-A-05)the Shanghai Public Health Youth Award(No.GWV-10.2-YQ24)the Three-Year Action Program of Shanghai Municipality for Strengthening the Construction of Public Health System(No.GWV-10.1-XK05).
文摘This cross-sectional study aimed to investigate the quality of care of diabetes in Shanghai,China.A total of 173235 patients with type 2 diabetes in 2017 were included in the analysis.Profiles of risk factors and intermediate outcomes were determined.The patients had a mean age of 66.43±8.12(standard deviation(SD))years and a mean diabetes duration of 7.95±5.53(SD)years.The percentage of patients who achieved the target level for HbA_(1c)(<7.0%)was 48.6%.Patients who achieved the target levels for blood pressure(BP)<130/80 mmHg and low-density lipoprotein-cholesterol(LDL-c)<2.6 mmol/L reached 17.5%and 34.0%,respectively.A total of 3.8%achieved all three target levels,and the value increased to 6.8%with an adaptation of the BP target level(<140/90 mmHg)for those over 65 years.Multivariable analysis identified the factors associated with a great likelihood of achieving all three target levels:male,young age,short diabetes duration,low body mass index,macrovascular complications,no microvascular complications,prescribed with lipid-lowering medication,and no prescription of antihypertensive medication.In conclusion,nearly 50%and one-third of the patients with diabetes met the target levels for HbA_(1c)and LDL-c,respectively,with a low percentage achieving the BP target level.The percentage of patients who achieved all three target levels needs significant improvement.
基金supported by the National Natural Science Foundation of China(Nos.21607027,52002142,51772118,and 51972134)the Opening Project of Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention(LAP3,No.FDLAP19007)+2 种基金and some Foundation of Anhui Province in China:Natural Science Foundation(Nos.1808085J24 and 2108085MB43)the University Natural Science Research Project(No.KJ2020A0126)the Cultivating Outstanding Talents(No.gxbjZD2020066).
文摘The significant increase of NO_(x)concentration causes severe damages to environment and human health.Light-driven photocatalytic technique affords an ideal solution for the removal of NO_(x)at ambient conditions.To enhance the performance of NO_(x)removal,1D,2D and 3D photocatalysts have been constructed as the light absorption and the separation of charge carriers can be manipulated through controlling the morphology of the photocatalyst.Related works mainly focused on the construction and modification of special morphologic photocatalyst,including element doping,heterostructure constructing,crystal facet exposing,defect sites introducing and so on.Moreover,the excellent performance of the photocatalytic NO_(x)removal creates great awareness of the application,which has promising practical applications in NO_(x)removal by paint(removing NO_(x)indoor and outdoor)and pavement(degrading vehicle exhausts).For these considerations,recent advances in special morphologic photocatalysts for NO_(x)removal was summarized and commented in this review.The purpose is to provide insights into understanding the relationship between morphology and photocatalytic performance,meanwhile,to promote the application of photocatalytic technology in NO_(x)degradation.
基金the Fundamental Research Funds for the Central Universities(No.30920021120)Key Laboratory of Biomass Energy and Material,Jiangsu Province(No.JSBEM201912)+1 种基金the National Natural Science Foundation of China(No.21905089)the Chinese Postdoctoral Science Foundation(No.2019M662775)for financial support。
文摘Organosilicon compounds play an important role in the fields of materials science,pharmacy,and organic synthesis.The development of effective approaches for the preparation of these compounds have also become a research focus in organic synthesis.In recent years,free radical synthesis of organosilicons has been vigorously developed,which generally has the advantages of milder synthesis conditions,higher yields and selectivity,and free of precious metal catalysts compared with traditional strategies.This article reviews research progresses in the synthesis of organosilico n compounds by free radical pathways since 2016.In most cases,the radical silylation is achieved based on the reaction of silyl radicals,which are triggered by four routes including peroxide,transition-metal-induced peroxide decomposition,alkali,photocatalysis.The alkyl radicals can also initiate the radical silylation for the generation of C(sp^(3))—Si bonds.
文摘Iodine catalyzed one-pot reactions of salicylaldehyde and dimolecular 1H-indene-l,3(2H)-dione, barbituric acids, 4-hydro- xycoumarin, or 4-hydroxy-6-methylpyran-2-one were performed and provided a rapid, convenient and general approach to synthesize the chromene derivatives. 2-(11-Oxo-10,11-dihydroindeno[1,2-b]chromen-10-yl)-lH-indene-1,3(2H)-diones P1-P4 and 10-(4-hydroxy-6-methyl-2-oxo-2H-pyran-3-yl)-3-methylpyrano[4,3-b]chromen-1(1OH)-ones P8-P9 were unprecedentedly prepared and structurally identified by NMR and Mass. The confirmation of structure by single crystal X-ray crystallography is reported for P3.
基金Key Laboratory of Biomass Energy and Material,Jiangsu Province(No.JSBEM201912)Chinese Postdoctoral Science Foundation(Nos.2015M571761 and 2016T90465)for financial support+1 种基金funded by the Priority Academic Program Development of Jiangsu Higher Education InstitutionInstrument and Equipment Foundation of Nanjing University of Science&Technology。
文摘Catalytic hydrodeoxygenation(HDO)is one of the most effective methods to upgrade the oxygen-containing compounds derived from coal tar to valuable hydrocarbons.Herein,an efficient bimetallic catalyst Pt_(1)Ni_(4)/MgO was prepared and applied in the HDO of dibenzofuran(DBF).High yield(95%)of the desired product bicyclohexane(BCH)was achieved at 240℃and 1.2 MPa of H_(2).Superior catalytic performance could be ascribed to the"relay catalysis"of Pt sites and Ni sites,and the reaction pathway is proposed as well.Scale-up experiment and recyclability test were also performed,which demonstrated the recyclability and promising potential application of Pt_(1)Ni_(4)/MgO.
基金the project of"Excellence Initiative"and"Zijin Star"in NJUST,"Doctoral Fund of Ministry of Education of China"(No.200802881024)"National Natural Science Foundation of China"(No.20902047) for financial support
文摘A convenient method for Morita-Baylis-Hillman reaction of arylaldehydes with methyl acrylate has been developed by using fluorous-tag organocatalyst 1-[4-(perfluorooctyl)phenyl]-3-phenylthiourea and DABCO at room temperature. The fluorous organocatalyst could be recovered from the reaction mixture by fluorous solid-phase extraction (F-SPE) with excellent purity for direct reuse.
文摘The macroeconomic policy environment affects the internal governance of microenterprises,which may provide opportunities for management to benefit from stock sales while decreasing its motivation to manipulate stock transactions.Using a sample of Chinese A-share listed companies from 2007 to2018,we study the impact of macroeconomic policy uncertainty on opportunistic insider trading.The results show that macroeconomic policy uncertainty helps restrain the opportunistic trading of shares held by management.When macroeconomic policies are uncertain,enterprises improve their internal governance.Furthermore,strengthening equity governance helps reduce management’s opportunistic use of the uncertainty of the policy environment,highlighting the advantageous effect of macroeconomic policy uncertainty and helping regulators standardize managerial behavior and promote the governance effect of macroeconomic policy.