The paper had introduced researches on urban forest park and analyzed its particularity.In terms of elimination of externality during development and tourism consumption process of urban forest park,real estate agent ...The paper had introduced researches on urban forest park and analyzed its particularity.In terms of elimination of externality during development and tourism consumption process of urban forest park,real estate agent had been introduced and two assumptions had been proposed to eliminate externality.As for elimination of externality during development of urban forest park,right to use planning land for urban forest park and surrounding land for real estate development would be sold to estate agent who would develop urban forest park and commodity house;the management of forest urban park would be undertaken by tourism development companies for which estate agent would make compensation.As for elimination of externality during tourism consumption process,it would control with policies and laws,or establish ticket system.As the study hadn't been conducted on policies about urban land and real estate,the feasibility of the first assumption needed to be further studied by environmental economists.展开更多
Understanding the connotation and principles of ecological compensation in water source reserve areas is the basis and guarantee for establishing and improving the ecological compensation mechanism of water source res...Understanding the connotation and principles of ecological compensation in water source reserve areas is the basis and guarantee for establishing and improving the ecological compensation mechanism of water source reserve areas.First,this paper reviews the three stages of ecological compensation research progress.Based on the review,using the theory of externality,the ecological environment system of water source reserve areas is then analyzed.This paper argues that the connotation of ecological compensation in water source reserve areas is a kind of institutional arrangement,which is designed to internalize externalities.Finally,based on the understanding of the connotation of ecological compensation in water source reserve areas,five principles for establishing and improving the ecological compensation mechanism are proposed,including the principle of fairness and justice,the principle of equivalence of equality and responsibility,the principle of flexibility and effectiveness,the principle of "earmark funds,and implementation by law," and the principle of government compensation supplemented with market compensation.展开更多
In the context of global climate change,the internalization of negative externality,which is brought about by the traditional mode of economic growth,has become an inevitable choice.In order to achieve the internaliza...In the context of global climate change,the internalization of negative externality,which is brought about by the traditional mode of economic growth,has become an inevitable choice.In order to achieve the internalization,it is necessary to make innovations on the market mechanism and system,find the value of environmental capital,establish a new mode of economic growth based on environmental capital,and then transform the environmental capital,an exogenous factor of economic growth,into an endogenous factor.Of this,the key of market mechanism and system innovation is the financial innovation that is based on environmental capital and negative externality;the government defines the initial property right of environmental resources and establishes environment energy trading market,so as to guide enterprises to trade environmental resources(represented by carbon emission permit trading) based on the Clean Development Mechanism,and to vigorously develop environmental finance and carbon finance.展开更多
According to the theories of institutional economics and development economics,the positive and negative externality of rural labor force flowing from central and western regions and into eastern regions of China were...According to the theories of institutional economics and development economics,the positive and negative externality of rural labor force flowing from central and western regions and into eastern regions of China were analyzed,and then it was proposed that it is necessary to positive externality,rather than take"household register"measures to solve the problem simply.展开更多
Externality;the term can define as a positive or negative impact from either production or consumption of goods or services.Services provided by particular location have very specific dependency on spatial characteris...Externality;the term can define as a positive or negative impact from either production or consumption of goods or services.Services provided by particular location have very specific dependency on spatial characteristics of that region.A region’s distinct characteristics make it ecologically unique from other such regions.Ecosystem services are offered by these regions thus differ according to these unique ecological features.In this particular study,artificially imposed expansion of coastal shrimp farming towards the inland and its impact over paddy cultivation have been addressed.Optimization of the extent of this manipulative coastal expansion has been supported by little modification of a previously described model.Here the investment prediction for both shrimp and paddy farming has been investigated by calculating net present value(NPV).Shrimp farming has very specific externality on local ecosystem services.In this particular case,some contradictory results are presented and with respect to positive or negative externality;but the externalities are strong.NPV results indicate that there is no long-term profitability in case of shrimp farming.Hence,an overall externality of shrimp farming has been described in context of this study.展开更多
Titanium alloy has the advantages of high strength,strong corrosion resistance,excellent high and low temperature mechanical properties,etc.,and is widely used in aerospace,shipbuilding,weapons and equipment,and other...Titanium alloy has the advantages of high strength,strong corrosion resistance,excellent high and low temperature mechanical properties,etc.,and is widely used in aerospace,shipbuilding,weapons and equipment,and other fields.In recent years,with the continuous increase in demand for medium-thick plate titanium alloys,corresponding welding technologies have also continued to develop.Therefore,this article reviews the research progress of deep penetration welding technology for medium-thick plate titanium alloys,mainly covering traditional arc welding,high-energy beam welding,and other welding technologies.Among many methods,narrow gap welding,hybrid welding,and external energy field assistance welding all contribute to improving the welding efficiency and quality of medium-thick plate titanium alloys.Finally,the development trend of deep penetration welding technology for mediumthick plate titanium alloys is prospected.展开更多
Using data from two well-known individual surveys in China,we estimate human capital externality.We find a positive and statistically significant effect of city-level human capital on individual earnings.Fixed-effects...Using data from two well-known individual surveys in China,we estimate human capital externality.We find a positive and statistically significant effect of city-level human capital on individual earnings.Fixed-effects estimates show a one-year increase in city average education could increase individual earnings between 7.3%and 8.9%.Our IV estimate indicates a 7.6%increase.This finding confirms a long-held belief by economists that there are external benefits of education that are not captured by the individuals who invested in human capital.By extension our finding also offers a justification for an active role of the government in promoting education.We also find that the estimated effect of human capital externality is larger in coastal cities than in non-coastal cities and is larger in the non-state sector than in the state sector.We ascribe these heterogeneities to differences in institutional and technological environments across cities and sectors.展开更多
Bcakground: Pancreatic pseudocyst (PPC) is a common complication arising from acute or chronic pancreatitis, trauma, or pancreatic duct obstruction. When acute fluid collection persists for 4 - 6 weeks and is encapsul...Bcakground: Pancreatic pseudocyst (PPC) is a common complication arising from acute or chronic pancreatitis, trauma, or pancreatic duct obstruction. When acute fluid collection persists for 4 - 6 weeks and is encapsulated by a fibrous wall, it is classified as a pancreatic pseudocyst. While PPC is generally asymptomatic in many patients, it can manifest with persistent abdominal pain, dyspepsia, intra-cystic infection, and potentially lead to gastrointestinal obstruction in some cases. Although smaller PPCs may resolve spontaneously, larger PPCs tend to be refractory to absorption and often necessitate surgical intervention to prevent complications such as intracystic hemorrhage. Objective: To explore the efficacy of percutaneous catheterization with negative pressure in the treatment of large pancreatic pseudocysts. Methods: The cases of large pancreatic pseudocysts treated in our hospital from 2004 to 2022 were retrospectively collected, and the general condition, operation time, drainage time, feeding time, postoperative complications, hospital stay, cost and follow-up of the patients were analyzed. Results: A total of 132 patients with large pancreatic pseudocysts were collected. The average operation time was 32.4 ± 2.1 min;The retention time of the drainage tube was 30 ± 1.8 days in the percutaneous negative pressure drainage group;The postoperative feeding time was no fasting after local anesthesia drainage;Postoperative complications (bleeding, infection, pancreatic leakage, recurrence, anastomotic leakage, etc.): Two of the 132 patients had recurrent cysts, which were cured by re-puncture and negative pressure drainage. The length of hospital stay was 6 ± 1.1 days;The cost was 11,200 ± 1300 yuan;Follow-up: The follow-up time ranged from 1 to 3 years, and the patients had no discomfort. Conclusion: Percutaneous catheterization and negative pressure drainage can effectively treat large pancreatic pseudocysts. Compared with other treatment methods, it is simple and effective, the postoperative recovery of patients is faster, the physical damage is less, the hospital stay is shorter, and the cost is lower.展开更多
High pressure die casting(HPDC)AlSi10Mn Mg alloy castings are widely used in the automobile industry.Mg can optimize the mechanical properties of castings through heat treatment,while the release of thermal stress aro...High pressure die casting(HPDC)AlSi10Mn Mg alloy castings are widely used in the automobile industry.Mg can optimize the mechanical properties of castings through heat treatment,while the release of thermal stress arouses the deformation of large integrated die-castings.Herein,the development of non-heat treatment Al alloys is becoming the hot topic.In addition,HPDC contains externally solidified crystals(ESCs),which are detrimental to the mechanical properties of castings.To achieve high strength and toughness of non-heat treatment die-casting Al-Si alloy,we used AlSi9Mn alloy as matrix with the introduction of Zr,Ti,Nb,and Ce.Their influences on ESCs and mechanical properties were systematically investigated through three-dimensional reconstruction and thermodynamic simulation.Our results reveal that the addition of Ti increased ESCs'size and porosity,while the introduction of Nb refined ESCs and decreased porosity.Meanwhile,large-sized Al_3(Zr,Ti)phases formed and degraded the mechanical properties.Subsequent introduction of Ce resulted in the poisoning effect and reduced mechanical properties.展开更多
The paper presents experimental investigation results of crack pattern change in cement pastes caused by external sulfate attack(ESA).To visualize the formation and development of cracks in cement pastes under ESA,an ...The paper presents experimental investigation results of crack pattern change in cement pastes caused by external sulfate attack(ESA).To visualize the formation and development of cracks in cement pastes under ESA,an X-ray computed tomography(X-ray CT)was used,i e,the tomography system of Zeiss Xradia 510 versa.The results indicate that X-CT can monitor the development process and distribution characteristics of the internal cracks of cement pastes under ESA with attack time.In addition,the C3A content in the cement significantly affects the damage mode of cement paste specimens during sulfate erosion.The damage of ordinary Portland cement(OPC)pastes subjected to sulfate attack with high C3A content are severe,while the damage of sulfate resistant Portland cement(SRPC)pastes is much smaller than that of OPC pastes.Furthermore,a quadratic function describes the correlation between the crack volume fraction and development depth for two cement pastes immermed in sulfate solution.展开更多
BACKGROUND Pain in the back or pelvis or fear of back pain may affect the timing or cocontraction of the core muscles.In both static and dynamic movements,the Sahrmann core stability test provides an assessment of cor...BACKGROUND Pain in the back or pelvis or fear of back pain may affect the timing or cocontraction of the core muscles.In both static and dynamic movements,the Sahrmann core stability test provides an assessment of core muscle activation and a person's ability to stabilize the lumbopelvic complex.Preparatory cues and images can be used to increase the activation of these muscles.To attain optimal movement patterns,it will be necessary to determine what cueing will give the most effective results for core stability.AIM To investigate the effects of external and internal cues on core muscle activation during the Sahrmann five-level core stability test.METHODS Total 68 participants(21.83±3.47 years)were randomly allocated to an external(n=35)or internal cue group(n=33).Participants performed the Sahrmann fivelevel core stability test without a cue as baseline and the five-level stability exercises with an internal or external cue.External cue group received a pressure biofeedback unit(PBU),and the internal cue group received an audio cue.A Delsys Trigno^(TM)surface electromyography unit was used for muscle activation from the rectus abdominis,external oblique,and transverse abdominis/internal oblique muscles.RESULTS Linear mixed effects model analysis showed that cueing had a significant effect on core muscle activation(P=0.001);however,there was no significant difference between cue types(internal or external)(P=0.130).CONCLUSION Both external and internal cueing have significant effects on core muscle activation during the Sahrmann five-level core stability test and the PBU does not create higher muscle activation than internal cueing.展开更多
The study conducted here is an attempt to answer the questions of where China stands as a recipient,what multilateral and bilateral aid has brought to China,and why.For the convenience of discussion,I shall concentrat...The study conducted here is an attempt to answer the questions of where China stands as a recipient,what multilateral and bilateral aid has brought to China,and why.For the convenience of discussion,I shall concentrate on:The period after 1979 when China started its economic reformOfficial Development Assistance (ODA) commitments and types of flows,andThe OECD figures.展开更多
Dear Editor,We aimed to describe the management of the intraoperative injury of the right external iliac artery that occurred during robot-assisted right nephroureterectomy with bladder cuff excision.Surgery was sched...Dear Editor,We aimed to describe the management of the intraoperative injury of the right external iliac artery that occurred during robot-assisted right nephroureterectomy with bladder cuff excision.Surgery was scheduled for suspected urothelial carcinoma of the distal ureter in a 60-year-old woman.The patient involved in the present research signed a dedicated form to consent to the publication of images and/or information about her.Past medical history included Brugada syndrome diagnosed in 2015,and hypercholesterolemia.Past surgical history included one cesarean section only.Family history included ovarian cancer(sister),colorectal cancer(mother),and kidney cancer(father).展开更多
This study explores whether the current external quality assessment(EQA)level and acceptable bias for basic semen analysis in China are clinically useful.We collected data of semen EQA from Andrology laboratories in t...This study explores whether the current external quality assessment(EQA)level and acceptable bias for basic semen analysis in China are clinically useful.We collected data of semen EQA from Andrology laboratories in the Hunan Province(China)in 2022 and searched for data in the published literature from January2000 to December 2023 in China.On the basis of these data,we analyzed the coefficients of variation and acceptable biases of different quality control materials for basic semen analysis through robust statistics.We compared these findings with quality specifications based on biological variation from optimal,desirable,and minimum levels of bias to seek a unified and more suitable semen EQAbias evaluation standard for China's national conditions.Different sources of semen quality control material exhibited considerable variation in acceptable biases among laboratories,ranging from 8.2%to 56.9%.A total of 50.0% of the laboratories met the minimum quality specifications for progressive motility(PR),whereas 100.0%and 75.0%of laboratories met only the minimum quality specifications for sperm concentration and total motility(nonprogressive[NP]+PR),respectively.The Z value for sperm concentration and PR+NP was equivalent to the desirable performance specification,whereas the Z value for PR was equivalent only to the minimum performance specification.This study highlights the feasibility of operating external quality assessment schemes for basic semen analysis using quality specifications based on biological variation.These specifications should be unified among external quality control(EQC)centers based on biological variation.展开更多
Basic life support for cardiac arrest associates cardiopulmonary resuscitation(CPR)and defibrillation.CPR relies on chest compressions(CC)and ventilation.Current guidelines on CPR recommend a depth of 5-6 cm at a rhyt...Basic life support for cardiac arrest associates cardiopulmonary resuscitation(CPR)and defibrillation.CPR relies on chest compressions(CC)and ventilation.Current guidelines on CPR recommend a depth of 5-6 cm at a rhythm of 100-120 times/min for CC.[1,2]Interruptions of the CC must be as short as possible and are related to ventilation,defibrillation and turnover of the rescuers.Most of the automated external defibrillators(AEDs)require interruptions of the CC to perform rhythm analysis.Among the numerous marketed models of AEDs,some provide real-time feedback about the quality of the CC.展开更多
The metamaterial based on external meshing gears(MEG)is designed based on the principle of external meshing gear transmission.Based on the meshing transmission principle of external meshing gears and planetary gear tr...The metamaterial based on external meshing gears(MEG)is designed based on the principle of external meshing gear transmission.Based on the meshing transmission principle of external meshing gears and planetary gear trains,the internal and external gear rings are designed.Based on the internal and external gear rings,the metamaterial based on inner and outer planetary gear trains(MIP)is designed to study the shear modulus,Young's modulus,and amplitude-frequency characteristics of the metamaterial based on gears at different angles.The effects of the number of planetary gears on the physical characteristics of the MIP are studied.The results show that the MEG can be continuously adjusted by adjusting the shear modulus and Young's modulus due to its meshing characteristics.With the same number of gears,the adjustment range of the MIP is larger than the adjustment range of the MEG.When the number of planetary gears increases,the adjustment range of the MIP decreases.Moreover,when the metamaterial based on gears rotates,the harmonic response changes with the change of the angle.展开更多
Direct numerical simulations of a uniform flow past a fixed spherical droplet are performed to investigate the parameter range within which the axisymmetric flow becomes unstable due to an external flow bifurcation.Th...Direct numerical simulations of a uniform flow past a fixed spherical droplet are performed to investigate the parameter range within which the axisymmetric flow becomes unstable due to an external flow bifurcation.The hydrodynamics is governed by three dimensionless parameters:the viscosity ratioμ*,the external Reynolds numbers Re^(e),and internal Reynolds numbers Re^(i),respectively.The drop-to-fluid density ratio is related to these parameters asρ*=μ*Re^(i)/Re^(e).This study focuses on highly viscous droplets withμ*≥5,where wake instability is driven by the vorticity flux transferred from the droplet surface into the surrounding fluid.By analysing the wake structure,we confirm that the onset of the external bifurcation is linked to the tilting of the azimuthal vorticityωϕ,in the wake and that the bifurcation occurs once the isocontours ofωϕalign nearly perpendicular to the symmetry axis.We propose an empirical criterion for predicting the onset of the external bifurcation,formulated in terms of the maximum vorticity on the external side of the droplet surface.This criterion is applicable for sufficiently high Re^(i) and holds over a wide range ofμ*and Re^(e).Additionally,we examine the bifurcation sequence for two specific external Reynolds numbers,Re^(e)=300 and Re^(e)=500,and show that,beyond a critical viscosity ratio,the axisymmetric wake first transitions to a steady planar-symmetric state before undergoing a secondary Hopf bifurcation.Finally,we highlight the influence of Re^(i) on external bifurcation and show that,at moderate Re^(i),wake instability may set in at a lower vorticity threshold than predicted by our criterion.These findings provide new insights into the external flow bifurcation of viscous droplets.展开更多
[Objectives]To observe the clinical efficacy of external application of Scorzonera Herpes Ointment combined with Methylprednisolone Sodium Succinate for Injection in the treatment of herpes zoster oticus(HZO).[Methods...[Objectives]To observe the clinical efficacy of external application of Scorzonera Herpes Ointment combined with Methylprednisolone Sodium Succinate for Injection in the treatment of herpes zoster oticus(HZO).[Methods]A total of 100 HZO patients admitted to the 988 th Hospital of the Joint Logistics Support Force and Henan Provincial People's Hospital from June 2021 to June 2023 were selected.They were divided into a treatment group and a control group using a random number table method,with 50 cases in each group.Both groups received Methylprednisolone Sodium Succinate for Injection.Additionally,the treatment group was treated with external application of Scorzonera Herpes Ointment,while the control group received acyclovir ointment.Both groups were treated for 10 d.The comparisons included clinical efficacy,total symptom and sign scores,pain level[Visual Analogue Scale(VAS)],time for erythema reduction,cessation of blister formation,scab formation,and scab shedding,incidence of post-herpetic neuralgia(PHN),air conduction hearing threshold,and air-bone gap.[Results]After 10 d of treatment,the total effective rate was 98.00%(49/50)in the treatment group and 84.00%(42/50)in the control group,with a statistically significant difference between the two groups(P<0.05).After 10 d of treatment,the total symptom and sign scores and VAS scores of both groups decreased compared to those before treatment.The treatment group had significantly lower scores than the control group(P<0.05).The treatment group showed significantly shorter time for erythema reduction,cessation of blister formation,scab formation,and scab shedding compared to the control group(P<0.05).During the 1-month follow-up after treatment,no PHN cases occurred in the treatment group,while the incidence of PHN in the control group was 24.00%(12/50),showing a statistically significant difference(P<0.05).After 10 d of treatment,both groups showed reduced air conduction hearing thresholds,and the treatment group exhibited significantly lower air conduction thresholds and air-bone gaps compared to the control group(P<0.05).No statistically significant difference was observed in the air-bone gap before and after treatment in the control group(P>0.05).[Conclusions]The combination of external application of Scorzonera Herpes Ointment and Methylprednisolone Sodium Succinate for Injection can alleviate pain and other discomforts,reduce PHN incidence,shorten disease duration,and improve hearing in HZO patients.展开更多
Management of post-traumatic long-bone defects remains relevant and cha-llenging despite the rapid development of approaches to their treatment.Do-minant positions are occupied by the Ilizarov method,bone autogenous g...Management of post-traumatic long-bone defects remains relevant and cha-llenging despite the rapid development of approaches to their treatment.Do-minant positions are occupied by the Ilizarov method,bone autogenous grafting and the Masquelet induced membrane technique(IMT).The IMT is aimed at reducing extensive defect treatment duration and for this reason has gained great popularity.However,the assessment of its effectiveness is difficult due to a limited number of clinical series.The varying clinical manifestations of bone defect severity do not allow a comprehensive evaluation of IMT effectiveness.One of them is infection in the defect area.The purpose of our literature review is an analysis of studies on IMT application in infected vs non-infected long-bone defects of the lower extremities published over the last 10 years.It focuses on the investigation of similarities and fundamental differences in the need for antibiotics,timing of spacer fixation,methods of collecting donor bone and fixators used for consolidation.The studies show that the IMT has been globally used in aseptic and osteomyelitic defects due to its clinical effectiveness.Authors’variations and improvements in its practical implementation indicate the ongoing development and the interest of researchers in this technique.展开更多
As an evaluation index,the natural frequency has the advantages of easy acquisition and quantitative evaluation.In this paper,the natural frequency is used to evaluate the performance of external cable reinforced brid...As an evaluation index,the natural frequency has the advantages of easy acquisition and quantitative evaluation.In this paper,the natural frequency is used to evaluate the performance of external cable reinforced bridges.Numerical examples show that compared with the natural frequencies of first-order modes,the natural frequencies of higher-order modes are more sensitive and can reflect the damage situation and external cable reinforcement effect of T-beam bridges.For damaged bridges,as the damage to the T-beam increases,the natural frequency value of the bridge gradually decreases.When the degree of local damage to the beam reaches 60%,the amplitude of natural frequency change exceeds 10%for the first time.The natural frequencies of the firstorder vibration mode and higher-order vibration mode can be selected as indexes for different degrees of the damaged T-beam bridges.For damaged bridges reinforced with external cables,the traditional natural frequency of the first-order vibration mode cannot be used as the index,which is insensitive to changes in prestress of the external cable.Some natural frequencies of higher-order vibration modes can be selected as indexes,which can reflect the reinforcement effect of externally prestressed damaged T-beam bridges,and its numerical value increases with the increase of external prestressed cable force.展开更多
文摘The paper had introduced researches on urban forest park and analyzed its particularity.In terms of elimination of externality during development and tourism consumption process of urban forest park,real estate agent had been introduced and two assumptions had been proposed to eliminate externality.As for elimination of externality during development of urban forest park,right to use planning land for urban forest park and surrounding land for real estate development would be sold to estate agent who would develop urban forest park and commodity house;the management of forest urban park would be undertaken by tourism development companies for which estate agent would make compensation.As for elimination of externality during tourism consumption process,it would control with policies and laws,or establish ticket system.As the study hadn't been conducted on policies about urban land and real estate,the feasibility of the first assumption needed to be further studied by environmental economists.
基金supported by National Social Science Fund "Study on the construction of ecological compensation system and the related policies of the water source protection zone"[Grant Number 14BJY027]Project of Humanities and Social Science Fund of Ministry of Education "Calculation and compensation method of ecological compensation in River Basin"[Grant Number 13YJA790025]
文摘Understanding the connotation and principles of ecological compensation in water source reserve areas is the basis and guarantee for establishing and improving the ecological compensation mechanism of water source reserve areas.First,this paper reviews the three stages of ecological compensation research progress.Based on the review,using the theory of externality,the ecological environment system of water source reserve areas is then analyzed.This paper argues that the connotation of ecological compensation in water source reserve areas is a kind of institutional arrangement,which is designed to internalize externalities.Finally,based on the understanding of the connotation of ecological compensation in water source reserve areas,five principles for establishing and improving the ecological compensation mechanism are proposed,including the principle of fairness and justice,the principle of equivalence of equality and responsibility,the principle of flexibility and effectiveness,the principle of "earmark funds,and implementation by law," and the principle of government compensation supplemented with market compensation.
基金Soft Science Project of Shanghai Science and Technology Development Fund,"Policy Research on Low Carbon Economy based on Carbon Finance Innovation and Low Carbon Industrial Chain"(Grant No.:10692103400)Project of the National Natural Science Foundation of China,"Research on Governance Strategy of Blockholders"(Grant No.:70802015)General project of Shanghai Philosophy and Social Sciences Planning,"The Main Factors that Influence China's Transformation of Economic Development Pattern in the Context of Dual Transitions"(Grant No.:2008BJL003).
文摘In the context of global climate change,the internalization of negative externality,which is brought about by the traditional mode of economic growth,has become an inevitable choice.In order to achieve the internalization,it is necessary to make innovations on the market mechanism and system,find the value of environmental capital,establish a new mode of economic growth based on environmental capital,and then transform the environmental capital,an exogenous factor of economic growth,into an endogenous factor.Of this,the key of market mechanism and system innovation is the financial innovation that is based on environmental capital and negative externality;the government defines the initial property right of environmental resources and establishes environment energy trading market,so as to guide enterprises to trade environmental resources(represented by carbon emission permit trading) based on the Clean Development Mechanism,and to vigorously develop environmental finance and carbon finance.
文摘According to the theories of institutional economics and development economics,the positive and negative externality of rural labor force flowing from central and western regions and into eastern regions of China were analyzed,and then it was proposed that it is necessary to positive externality,rather than take"household register"measures to solve the problem simply.
基金University Grants Commission(UGC)NET fellowship[Ref No.F.16-6(DEC.2016)/2017(NET)]University Grants Commission(UGC)for D S Kothari fellowship reference no.BL/17-18/0490.
文摘Externality;the term can define as a positive or negative impact from either production or consumption of goods or services.Services provided by particular location have very specific dependency on spatial characteristics of that region.A region’s distinct characteristics make it ecologically unique from other such regions.Ecosystem services are offered by these regions thus differ according to these unique ecological features.In this particular study,artificially imposed expansion of coastal shrimp farming towards the inland and its impact over paddy cultivation have been addressed.Optimization of the extent of this manipulative coastal expansion has been supported by little modification of a previously described model.Here the investment prediction for both shrimp and paddy farming has been investigated by calculating net present value(NPV).Shrimp farming has very specific externality on local ecosystem services.In this particular case,some contradictory results are presented and with respect to positive or negative externality;but the externalities are strong.NPV results indicate that there is no long-term profitability in case of shrimp farming.Hence,an overall externality of shrimp farming has been described in context of this study.
基金financially supported by the Key Research and Development Program of Ningbo(Grant No.2023Z098)Natural Science Foundation of Inner Mongolia(Grant No.2023MS05040)+1 种基金Shenyang Collaborative Innovation Center Project for Multiple Energy Fields Composite Processing of Special Materials(Grant No.JG210027)Shenyang Key Technology Special Project of The Open Competition Mechanism to Select the Best Solution(Grant Nos.2022210101000827,2022-0-43-048).
文摘Titanium alloy has the advantages of high strength,strong corrosion resistance,excellent high and low temperature mechanical properties,etc.,and is widely used in aerospace,shipbuilding,weapons and equipment,and other fields.In recent years,with the continuous increase in demand for medium-thick plate titanium alloys,corresponding welding technologies have also continued to develop.Therefore,this article reviews the research progress of deep penetration welding technology for medium-thick plate titanium alloys,mainly covering traditional arc welding,high-energy beam welding,and other welding technologies.Among many methods,narrow gap welding,hybrid welding,and external energy field assistance welding all contribute to improving the welding efficiency and quality of medium-thick plate titanium alloys.Finally,the development trend of deep penetration welding technology for mediumthick plate titanium alloys is prospected.
基金supported by the National Natural Science Foundation of China,Youth Foundation Program(No.71403292)the National Natural Science Foundation of China,General Program(No.71273288).
文摘Using data from two well-known individual surveys in China,we estimate human capital externality.We find a positive and statistically significant effect of city-level human capital on individual earnings.Fixed-effects estimates show a one-year increase in city average education could increase individual earnings between 7.3%and 8.9%.Our IV estimate indicates a 7.6%increase.This finding confirms a long-held belief by economists that there are external benefits of education that are not captured by the individuals who invested in human capital.By extension our finding also offers a justification for an active role of the government in promoting education.We also find that the estimated effect of human capital externality is larger in coastal cities than in non-coastal cities and is larger in the non-state sector than in the state sector.We ascribe these heterogeneities to differences in institutional and technological environments across cities and sectors.
文摘Bcakground: Pancreatic pseudocyst (PPC) is a common complication arising from acute or chronic pancreatitis, trauma, or pancreatic duct obstruction. When acute fluid collection persists for 4 - 6 weeks and is encapsulated by a fibrous wall, it is classified as a pancreatic pseudocyst. While PPC is generally asymptomatic in many patients, it can manifest with persistent abdominal pain, dyspepsia, intra-cystic infection, and potentially lead to gastrointestinal obstruction in some cases. Although smaller PPCs may resolve spontaneously, larger PPCs tend to be refractory to absorption and often necessitate surgical intervention to prevent complications such as intracystic hemorrhage. Objective: To explore the efficacy of percutaneous catheterization with negative pressure in the treatment of large pancreatic pseudocysts. Methods: The cases of large pancreatic pseudocysts treated in our hospital from 2004 to 2022 were retrospectively collected, and the general condition, operation time, drainage time, feeding time, postoperative complications, hospital stay, cost and follow-up of the patients were analyzed. Results: A total of 132 patients with large pancreatic pseudocysts were collected. The average operation time was 32.4 ± 2.1 min;The retention time of the drainage tube was 30 ± 1.8 days in the percutaneous negative pressure drainage group;The postoperative feeding time was no fasting after local anesthesia drainage;Postoperative complications (bleeding, infection, pancreatic leakage, recurrence, anastomotic leakage, etc.): Two of the 132 patients had recurrent cysts, which were cured by re-puncture and negative pressure drainage. The length of hospital stay was 6 ± 1.1 days;The cost was 11,200 ± 1300 yuan;Follow-up: The follow-up time ranged from 1 to 3 years, and the patients had no discomfort. Conclusion: Percutaneous catheterization and negative pressure drainage can effectively treat large pancreatic pseudocysts. Compared with other treatment methods, it is simple and effective, the postoperative recovery of patients is faster, the physical damage is less, the hospital stay is shorter, and the cost is lower.
基金financially supported by the National Natural Science Foundation of China(Nos.52175284 and 52474396)the National Key Research and Development Program of China(No.2022YFB3404201)。
文摘High pressure die casting(HPDC)AlSi10Mn Mg alloy castings are widely used in the automobile industry.Mg can optimize the mechanical properties of castings through heat treatment,while the release of thermal stress arouses the deformation of large integrated die-castings.Herein,the development of non-heat treatment Al alloys is becoming the hot topic.In addition,HPDC contains externally solidified crystals(ESCs),which are detrimental to the mechanical properties of castings.To achieve high strength and toughness of non-heat treatment die-casting Al-Si alloy,we used AlSi9Mn alloy as matrix with the introduction of Zr,Ti,Nb,and Ce.Their influences on ESCs and mechanical properties were systematically investigated through three-dimensional reconstruction and thermodynamic simulation.Our results reveal that the addition of Ti increased ESCs'size and porosity,while the introduction of Nb refined ESCs and decreased porosity.Meanwhile,large-sized Al_3(Zr,Ti)phases formed and degraded the mechanical properties.Subsequent introduction of Ce resulted in the poisoning effect and reduced mechanical properties.
基金Funded by Chinese National Natural Science Foundation of China(No.U2006224)。
文摘The paper presents experimental investigation results of crack pattern change in cement pastes caused by external sulfate attack(ESA).To visualize the formation and development of cracks in cement pastes under ESA,an X-ray computed tomography(X-ray CT)was used,i e,the tomography system of Zeiss Xradia 510 versa.The results indicate that X-CT can monitor the development process and distribution characteristics of the internal cracks of cement pastes under ESA with attack time.In addition,the C3A content in the cement significantly affects the damage mode of cement paste specimens during sulfate erosion.The damage of ordinary Portland cement(OPC)pastes subjected to sulfate attack with high C3A content are severe,while the damage of sulfate resistant Portland cement(SRPC)pastes is much smaller than that of OPC pastes.Furthermore,a quadratic function describes the correlation between the crack volume fraction and development depth for two cement pastes immermed in sulfate solution.
文摘BACKGROUND Pain in the back or pelvis or fear of back pain may affect the timing or cocontraction of the core muscles.In both static and dynamic movements,the Sahrmann core stability test provides an assessment of core muscle activation and a person's ability to stabilize the lumbopelvic complex.Preparatory cues and images can be used to increase the activation of these muscles.To attain optimal movement patterns,it will be necessary to determine what cueing will give the most effective results for core stability.AIM To investigate the effects of external and internal cues on core muscle activation during the Sahrmann five-level core stability test.METHODS Total 68 participants(21.83±3.47 years)were randomly allocated to an external(n=35)or internal cue group(n=33).Participants performed the Sahrmann fivelevel core stability test without a cue as baseline and the five-level stability exercises with an internal or external cue.External cue group received a pressure biofeedback unit(PBU),and the internal cue group received an audio cue.A Delsys Trigno^(TM)surface electromyography unit was used for muscle activation from the rectus abdominis,external oblique,and transverse abdominis/internal oblique muscles.RESULTS Linear mixed effects model analysis showed that cueing had a significant effect on core muscle activation(P=0.001);however,there was no significant difference between cue types(internal or external)(P=0.130).CONCLUSION Both external and internal cueing have significant effects on core muscle activation during the Sahrmann five-level core stability test and the PBU does not create higher muscle activation than internal cueing.
文摘The study conducted here is an attempt to answer the questions of where China stands as a recipient,what multilateral and bilateral aid has brought to China,and why.For the convenience of discussion,I shall concentrate on:The period after 1979 when China started its economic reformOfficial Development Assistance (ODA) commitments and types of flows,andThe OECD figures.
文摘Dear Editor,We aimed to describe the management of the intraoperative injury of the right external iliac artery that occurred during robot-assisted right nephroureterectomy with bladder cuff excision.Surgery was scheduled for suspected urothelial carcinoma of the distal ureter in a 60-year-old woman.The patient involved in the present research signed a dedicated form to consent to the publication of images and/or information about her.Past medical history included Brugada syndrome diagnosed in 2015,and hypercholesterolemia.Past surgical history included one cesarean section only.Family history included ovarian cancer(sister),colorectal cancer(mother),and kidney cancer(father).
基金supported by the Hunan Province Municipal Natural Science Foundation(2022JJ30018)the Hunan Province Health Commission Science Foundation(B202301037899)to WNL。
文摘This study explores whether the current external quality assessment(EQA)level and acceptable bias for basic semen analysis in China are clinically useful.We collected data of semen EQA from Andrology laboratories in the Hunan Province(China)in 2022 and searched for data in the published literature from January2000 to December 2023 in China.On the basis of these data,we analyzed the coefficients of variation and acceptable biases of different quality control materials for basic semen analysis through robust statistics.We compared these findings with quality specifications based on biological variation from optimal,desirable,and minimum levels of bias to seek a unified and more suitable semen EQAbias evaluation standard for China's national conditions.Different sources of semen quality control material exhibited considerable variation in acceptable biases among laboratories,ranging from 8.2%to 56.9%.A total of 50.0% of the laboratories met the minimum quality specifications for progressive motility(PR),whereas 100.0%and 75.0%of laboratories met only the minimum quality specifications for sperm concentration and total motility(nonprogressive[NP]+PR),respectively.The Z value for sperm concentration and PR+NP was equivalent to the desirable performance specification,whereas the Z value for PR was equivalent only to the minimum performance specification.This study highlights the feasibility of operating external quality assessment schemes for basic semen analysis using quality specifications based on biological variation.These specifications should be unified among external quality control(EQC)centers based on biological variation.
文摘Basic life support for cardiac arrest associates cardiopulmonary resuscitation(CPR)and defibrillation.CPR relies on chest compressions(CC)and ventilation.Current guidelines on CPR recommend a depth of 5-6 cm at a rhythm of 100-120 times/min for CC.[1,2]Interruptions of the CC must be as short as possible and are related to ventilation,defibrillation and turnover of the rescuers.Most of the automated external defibrillators(AEDs)require interruptions of the CC to perform rhythm analysis.Among the numerous marketed models of AEDs,some provide real-time feedback about the quality of the CC.
基金supported by the Guangxi Science and Technology Major Program of China(Nos.AA23073019 and AA24263074)the National Natural Science Foundation of China(No.52265004)+7 种基金the Guangxi Natural Science Fund for Distinguished Young Scholars of China(No.2024JJG160014)the Innovation Project of Guangxi Graduate Education of China(No.YCSW2024119)the Open Fund of State Key Laboratory of Intelligent Manufacturing Equipment and Technology of China(No.IMETKF2025021)the Open Research Fund of State Key Laboratory of Precision Manufacturing for Extreme Service Performance-Central South University of China(No.Kfkt2023-06)the Open Fund of High-end Basic Component Innovation Station of China(No.KY01080030124001)the Open Fund for Academician Mao Ming's Workstation of China(No.XSJSFW-QNKXJ-202404-007)the Technology Innovation Platform Project of China Aviation Engine Group Corporation(No.CXPT-2023-044)the Open Fund for Innovation Workstation in the National Defense Science and Technology Innovation Special Zone(Xi'an Jiaotong University).
文摘The metamaterial based on external meshing gears(MEG)is designed based on the principle of external meshing gear transmission.Based on the meshing transmission principle of external meshing gears and planetary gear trains,the internal and external gear rings are designed.Based on the internal and external gear rings,the metamaterial based on inner and outer planetary gear trains(MIP)is designed to study the shear modulus,Young's modulus,and amplitude-frequency characteristics of the metamaterial based on gears at different angles.The effects of the number of planetary gears on the physical characteristics of the MIP are studied.The results show that the MEG can be continuously adjusted by adjusting the shear modulus and Young's modulus due to its meshing characteristics.With the same number of gears,the adjustment range of the MIP is larger than the adjustment range of the MEG.When the number of planetary gears increases,the adjustment range of the MIP decreases.Moreover,when the metamaterial based on gears rotates,the harmonic response changes with the change of the angle.
基金supported by the Deutsche Forschungsgemeinschaft(DFG)(Grant No.501298479)。
文摘Direct numerical simulations of a uniform flow past a fixed spherical droplet are performed to investigate the parameter range within which the axisymmetric flow becomes unstable due to an external flow bifurcation.The hydrodynamics is governed by three dimensionless parameters:the viscosity ratioμ*,the external Reynolds numbers Re^(e),and internal Reynolds numbers Re^(i),respectively.The drop-to-fluid density ratio is related to these parameters asρ*=μ*Re^(i)/Re^(e).This study focuses on highly viscous droplets withμ*≥5,where wake instability is driven by the vorticity flux transferred from the droplet surface into the surrounding fluid.By analysing the wake structure,we confirm that the onset of the external bifurcation is linked to the tilting of the azimuthal vorticityωϕ,in the wake and that the bifurcation occurs once the isocontours ofωϕalign nearly perpendicular to the symmetry axis.We propose an empirical criterion for predicting the onset of the external bifurcation,formulated in terms of the maximum vorticity on the external side of the droplet surface.This criterion is applicable for sufficiently high Re^(i) and holds over a wide range ofμ*and Re^(e).Additionally,we examine the bifurcation sequence for two specific external Reynolds numbers,Re^(e)=300 and Re^(e)=500,and show that,beyond a critical viscosity ratio,the axisymmetric wake first transitions to a steady planar-symmetric state before undergoing a secondary Hopf bifurcation.Finally,we highlight the influence of Re^(i) on external bifurcation and show that,at moderate Re^(i),wake instability may set in at a lower vorticity threshold than predicted by our criterion.These findings provide new insights into the external flow bifurcation of viscous droplets.
基金Supported by the Joint Construction Project of Medical Science and Technology Research Plan in Henan Province(LHGJ20190879).
文摘[Objectives]To observe the clinical efficacy of external application of Scorzonera Herpes Ointment combined with Methylprednisolone Sodium Succinate for Injection in the treatment of herpes zoster oticus(HZO).[Methods]A total of 100 HZO patients admitted to the 988 th Hospital of the Joint Logistics Support Force and Henan Provincial People's Hospital from June 2021 to June 2023 were selected.They were divided into a treatment group and a control group using a random number table method,with 50 cases in each group.Both groups received Methylprednisolone Sodium Succinate for Injection.Additionally,the treatment group was treated with external application of Scorzonera Herpes Ointment,while the control group received acyclovir ointment.Both groups were treated for 10 d.The comparisons included clinical efficacy,total symptom and sign scores,pain level[Visual Analogue Scale(VAS)],time for erythema reduction,cessation of blister formation,scab formation,and scab shedding,incidence of post-herpetic neuralgia(PHN),air conduction hearing threshold,and air-bone gap.[Results]After 10 d of treatment,the total effective rate was 98.00%(49/50)in the treatment group and 84.00%(42/50)in the control group,with a statistically significant difference between the two groups(P<0.05).After 10 d of treatment,the total symptom and sign scores and VAS scores of both groups decreased compared to those before treatment.The treatment group had significantly lower scores than the control group(P<0.05).The treatment group showed significantly shorter time for erythema reduction,cessation of blister formation,scab formation,and scab shedding compared to the control group(P<0.05).During the 1-month follow-up after treatment,no PHN cases occurred in the treatment group,while the incidence of PHN in the control group was 24.00%(12/50),showing a statistically significant difference(P<0.05).After 10 d of treatment,both groups showed reduced air conduction hearing thresholds,and the treatment group exhibited significantly lower air conduction thresholds and air-bone gaps compared to the control group(P<0.05).No statistically significant difference was observed in the air-bone gap before and after treatment in the control group(P>0.05).[Conclusions]The combination of external application of Scorzonera Herpes Ointment and Methylprednisolone Sodium Succinate for Injection can alleviate pain and other discomforts,reduce PHN incidence,shorten disease duration,and improve hearing in HZO patients.
文摘Management of post-traumatic long-bone defects remains relevant and cha-llenging despite the rapid development of approaches to their treatment.Do-minant positions are occupied by the Ilizarov method,bone autogenous grafting and the Masquelet induced membrane technique(IMT).The IMT is aimed at reducing extensive defect treatment duration and for this reason has gained great popularity.However,the assessment of its effectiveness is difficult due to a limited number of clinical series.The varying clinical manifestations of bone defect severity do not allow a comprehensive evaluation of IMT effectiveness.One of them is infection in the defect area.The purpose of our literature review is an analysis of studies on IMT application in infected vs non-infected long-bone defects of the lower extremities published over the last 10 years.It focuses on the investigation of similarities and fundamental differences in the need for antibiotics,timing of spacer fixation,methods of collecting donor bone and fixators used for consolidation.The studies show that the IMT has been globally used in aseptic and osteomyelitic defects due to its clinical effectiveness.Authors’variations and improvements in its practical implementation indicate the ongoing development and the interest of researchers in this technique.
基金supported by Henan Province Science and Technology Research Funding Project(No.222102320129)the Key Research Project of Henan Higher Education Institutions(Grant Nos.22A560004,22A56005).
文摘As an evaluation index,the natural frequency has the advantages of easy acquisition and quantitative evaluation.In this paper,the natural frequency is used to evaluate the performance of external cable reinforced bridges.Numerical examples show that compared with the natural frequencies of first-order modes,the natural frequencies of higher-order modes are more sensitive and can reflect the damage situation and external cable reinforcement effect of T-beam bridges.For damaged bridges,as the damage to the T-beam increases,the natural frequency value of the bridge gradually decreases.When the degree of local damage to the beam reaches 60%,the amplitude of natural frequency change exceeds 10%for the first time.The natural frequencies of the firstorder vibration mode and higher-order vibration mode can be selected as indexes for different degrees of the damaged T-beam bridges.For damaged bridges reinforced with external cables,the traditional natural frequency of the first-order vibration mode cannot be used as the index,which is insensitive to changes in prestress of the external cable.Some natural frequencies of higher-order vibration modes can be selected as indexes,which can reflect the reinforcement effect of externally prestressed damaged T-beam bridges,and its numerical value increases with the increase of external prestressed cable force.
