A structural vector autoregressive model and spillover index analysis based on generalized prediction error variance decomposition were used to explore the impact of public health emergencies on the dry bulk shipping market and provide suggestions for addressing the impact of public health emergencies. Moreover, the risk fluctuation and spillover of the dry bulk shipping market during public health emergencies were analyzed to understand the ways in which public health emergencies impact the dry bulk shipping market and to quantify the impact intensity. In related studies, the influence of the international crude oil price index and dry bulk ship port berthing volume were also considered. The results show that considering the immediate impact, the increase of newly confirmed cases of COVID-19 has a significant impact on the dry bulk shipping market, which lasts for more than 3 weeks and is always a negative shock. Different types of public health emergencies have different effects on the dry bulk shipping segmented shipping market. Dry bulk shipping companies should fully understand the development of public health emergencies, make full use of risk aversion forecasting tools in financial markets and make deployments for different situations. The first public case was reported on December 31, 2019, and the World Health Organization declared the 2019 novel coronavirus (COVID-19) a global pandemic on March 11, 2020. Although the severity of the pandemic in different countries and regions is different in terms of the number of confirmed cases, each country and region has been negatively affected, and the negative impacts continue to spread.A safe and stable external environment is the foundation of the sound development of each industry’s economy. The prevention of a series of abrupt public health events has always been an important issue for every economy and industry. In recent years, with the global outbreak of major public health emergencies such as the SARS pandemic, the Zika virus epidemic, and the COVID-19 pandemic, public health emergencies have received increasing attention because of their high degree of suddenness, low regularity and high transmission and their strong impact on economic development. As an important bridge of economic globalization, dry bulk shipping actively helps construct the “Sea route of the new Silk Road”. The dry bulk shipping market, which has always been closely related to the development of economic globalization, is sensitive to the impact of sudden public health events that impact the global economy.In this context, it is conducive to the sound development of dry bulk shipping, the globalization of service economy in the perspective of goods, capital, technology, personnel circulation and provide power and space for economic growth by analyzing the impact of public health emergencies on the dry bulk shipping market and the risk volatility of the dry bulk shipping segment market.According to current research and the impact of public health emergencies on markets in general, Baldwin and Tomiura predicted that the outbreak of COVID-19 would have an impact on both supply and demand of the global economy and a significant impact on international trade . Feyisa In general, the COVID-19 public health emergency has had a huge impact on the smooth operation of the global economy. The above documents provide many ideas for this article to explore the path analysis of the impact of public health emergencies on the dry bulk shipping market.According to current research and the impact of public health emergencies on shipping markets, Zhang Yongfeng and others believe that the daily increase of the COVID-19 pandemic has a significant Granger causality with the BDI index . Xu PeihThe impact of public health emergencies on the shipping market is sudden and severe. The impact of different public health emergencies on the risk volatility and spillover of the dry bulk shipping market is less researched.As shown in The COVID-19 pandemic was selected to explore the effect of the public health emergency on the dry bulk shipping market.The Baltic Dry Bulk Freight Index (BDI index) was selected to reflect the overall development of the dry bulk shipping market. Newly diagnosed pneumonia cases (COVID-19) were selected to reflect the development of the COVID-19 pandemic. The impact of the COVID-19 pandemic on the dry bulk shipping market was explored through the interaction between the two. At the same time, to perfect the exploration of the impact angle, the supply-side European Brent crude price index (EBSP) reflects the influence of the supply-side international crude oil market and the demand-side Clarkson Company’s statistics of the daily port calls of bulk carriers above 65,000 dwt (Dead Weight Tonnage) reflect the actual demand of the dry bulk shipping market to further analyze the impact of the COVID-19 pandemic on the international dry bulk shipping market. The number of port calls per day reflects the real state of the dry bulk shipping market to a certain extent.The COVID-19 pandemic in China gradually faded away after the “unblocking” of Wuhan. The major trading powers adopted trade intervention with a relatively lifted ban. The dry bulk shipping market and related enterprises have gradually resumed under the series of shocks . FurtherThe BCI, BHI and BPI indices issued by the Baltic shipping Union represent the Capsize dry bulk market, the (Super) Handysize dry bulk market and the Panamax dry bulk market, respectively. The outbreak of the COVID-19 pandemic and the study period of the Zika virus were selected from January 3, 2020 to April 8, 2020 and February 1, 2016 to July 31, 2016, respectively. In February 2016, the World Health Organization (WHO) announced that the Zika epidemic in Brazil was a public health emergency of international concern, so February 1, 2016, was chosen as the starting time of the impact period of the Zika epidemic in Brazil. In September of the same year, the WHO announced that no laboratory-confirmed Zika virus cases were found in Brazil during the Olympic Games (August and September 2016). In November, it announced that the pheic status of the Zika virus epidemic in Brazil was lifted . To makePublic health emergencies are closely related to population mobility and directly affect public consumption, business tourism transportation and logistics and other industries. With population flows, public health emergencies tend to accelerate the spread of the disease. In real life, an effective and widely used strategy to limit the spread and development of public health emergencies worldwide is to limit the large-scale flow of the population. China has controlled COVID-19 well, which is the most effective way to implement the policy and is an effective way to curb the spread of public health emergencies and to prevent the spread of the pandemic.With the disposal method of "early detection, early isolation and early treatment" being accepted by an increasing number of countries, the means of shutdown, suspension of production, suspension of schools, road closures and even comprehensive "city closures" are carried out around the world. The implementation of an extensive segregation policy depresses the commodity consumption industry, which directly and indirectly affects the logistics and transportation industry, including dry bulk shipping.With the further development of the internationalization strategy of the world’s large shipping enterprises, the shipping market, as a link between the means of production and the rest of the world, occupies an important position in the global supply chain. According to the statistics of the United Nations Commission for trade development, the volume of seaborne trade accounts for 90% of the total global trade in weight and for more than 70% of the trade volume in value. As shown in Due to the large volume difference between the data, to reduce the volatility of the daily data of the time series and the influence of the order of magnitude between different series, four groups of data are logarithmically processed, and the trend of the processed data is shown in In the process of time series data analysis, because of its nonstationary characteristics, pseudoregression events often occur. To avoid pseudoregression, the stationarity of time series variables should be tested before analysis. The ADF (Augmented Dickey-Fuller test) test method is often used to test the stationarity of variables. The form of the ADF test equation is as followsThe results obtained by Eviews analysis software are shown in Using a time series to build a model, we need to test whether there is a cointegration relationship between variables based on stable data. Therefore, it is necessary to test the cointegration of the series. The cointegration test determines whether there is a long-term equilibrium relationship between time series. This paper uses the trace test method proposed by Johansen and Juselius (1990) to test the cointegration relationship between variables. The test formula is as follows (2)EViews analysis software was used to test the cointegration relationship between BDI and dcov, and the results are shown in The VAR model is usually used in the prediction of time series and the dynamic impact of random disturbance on the system to explain the impact of dynamic impact on variables. The basic mathematical expression of the model is shown in Formula (3), and the meaning of the variables is shown in The optimal lag order of the model is selected according to the AIC and SC criterion. The analysis results are shown in Through the analysis of The optimal model Eqs  and 5)  5) are oThe Granger causality test is often used to judge the causality between variables, that is, whether the change of one variable is the cause of the change of another variable. On this basis, the causal direction of the two is tested. Next, the optimal VAR model calculated above is used for the causality test. The inspection results are shown in According to Granger causality test results are consistent with the development of reality and corroborate the impact of the COVID-19 public health emergency on the dry bulk shipping market. The global spread of public health emergencies has a direct impact on the trade side. At the same time, due to the strong demand and high dependence on seafarers and other means of production, the dry bulk shipping market has had a relatively strong impact. The COVID-19 pandemic was mainly affected by the policies of various countries and regions in the sample period and was closely related to passenger transport. The development of a dry bulk shipping market dominated by cargo transport is not significant. Under the background of global supply chain development, the dry bulk shipping market is strongly correlated with the development of public health emergencies.In the analysis of the VAR model, the real-time structural relationship among system variables is hidden in the random disturbance term, and the explanation of this part is ignored. The SVAR model adds synchronous variables to the VAR model, which can directly reflect the real-time structural relationship among variables . The BDIAmong them, matrix A is the synchronous relation matrix between endogenous variables in the model, and it is the white noise vector.Formula (7) is obtained by multiplying both sides of the VAR model by the synchronous relation matrix A at the same time.Formula (8) can be obtained by simultaneous Formulas (6) and (7)μt to μt = Bet, the estimation model Formula (9) of the AB-type SVAR model is obtained:After orthogonalization, that is, orthogonalizing m(m−1)/2 constraints, namely, one constraint. According to the economic meaning, the restriction condition is as follows: The development of COVID-19 has a current effect on the freight rate of the dry bulk shipping market.In this paper, the SVAR model is identified by establishing short-term constraints. Because the model includes two endogenous variables, it needs to impose After setting constraints and sorting out, the form of After importing EViews measurement software, the estimated values of matrix parameters and related data are obtained after maximum likelihood estimation, as shown in By exploring the impulse response of the SVAR model, we can investigate the impact effect of public health emergencies on dry bulk shipping in different periods. The premise of the impulse response is that the model is stable, so it is necessary to carry out AR root tests on the model to judge whether the model is stable or not. The AR root test results are shown in Based on the stability of the model, the impulse response is analyzed. The purpose of this study is to analyze the dynamic impact of the COVID-19 public health emergency on the dry bulk shipping market represented by the BDI index. The solid line in The COVID-19 pandemic has a significant impact on the dry bulk shipping market; the impact duration is more than 3 weeks, and it always has a negative impact, as shown in As shown in the variance decomposition chart of By studying the impact of the COVID-19 pandemic’s public health emergency on the BDI index, we discovered that there was no cointegration relationship between the BDI index and newly confirmed pneumonia cases related to COVID-19 at the 5% confidence level. The Granger causality test showed a one-way causal relationship between the COVID-19 pandemic and the dry bulk shipping market. Impulse response analysis showed that dry bulk shipping was significantly negatively impacted by the volatility of confirmed new cases of COVID-19, with a duration of more than 3 weeks. The increase in the impact of COVID-19 confirmed cases’ reached the highest point in the short term (1–3 days) for the dry bulk shipping market and related enterprises. The impact will gradually decrease, but it will last more than 3 weeks. The result of variance decomposition proved that dry bulk shipping was deeply impacted by the COVID-19 public health emergency.Thus, the dry bulk shipping market quickly received external shocks by the COVID-19 pandemic. Dry bulk shipping enterprises need to be alert that the external impact will reach the maximum in the short term (1–3 days) and will last more than 3 weeks in the long term. Before taking effective measures, the impact of public health emergencies will continue to impact the market in waves, greatly affecting the performance and cash flow of enterprises.Diebold and Yilmaz (2014) proposed the spillover index method based on generalized prediction error variance decomposition to measure the risk spillover effect among financial sectors and then described the risk transmission relationship among sectors . The modTaking the logarithm of the return index of each dry bulk shipping market segment, the logarithmic rate of return of each ship type market segment is obtained, generalized variance decomposition is carried out, and the risk volatility spillover index is obtained after calculation. On this basis, the risk volatility spillover correlation matrix of the dry bulk shipping subdivision ship type is constructed.In By comparing the performance of the shipping rate index in the years before and after the public health emergency, the impact of the COVID-19 pandemic on the dry bulk shipping market is examined more directly to lay a structural foundation for an in-depth analysis of risk transfer between market segments. The outbreak of the COVID-19 pandemic is a worldwide public health event that affects worldwide demand for major countries in international trade and major sources of production. The impact on dry bulk shipping is reflected not only in the contraction of transport prices but also in the transport structure of dry bulk shipping. As shown in Using spillover index analysis, we obtained the risk volatility spillover matrix of the dry bulk shipping market during the period of COVID-19. The incidence of Zika virus infection is relatively small compared to that of COVID-19, and it mainly affects the place of origin of international trade production, which is not the only one. By observing the changes in the freight index of dry bulk shipping in the first three quarters of 2015 and 2016 before and after the outbreak of the Zika virus, it can be seen in By using spillover index analysis, the risk volatility spillover matrix of each ship type in the dry bulk shipping market during the Zika epidemic is obtained, as shown in Comparing the freight rate performance of each shipping type before and after the outbreak of two public health emergencies and comparing Figs Considering the overall risk volatility spillover of the dry bulk shipping market, by comparing the risk volatility spillover in Tables During the Zika outbreak in 2016, the increase of iron ore shares on China–Brazil routes helped increase demand, the further development of intermediate frequency furnace events positively impacted the import demand of iron ore, and the large-scale steel-making movement in India increased the demand for coking coal carbon trade, in response to which the demand for dry bulk shipping rose steadily. At a time when the large-scale development of ships is in full swing, capsize dry bulk shipping has made great progress, and the market enjoys the benefit of marginal cost reductions. With the advantages of high deadweight tonnage, strong adaptability, and low unit cost, the capsize dry bulk carrier occupies a dominant position in the dry bulk shipping market. According to the market rule of large ships with large lines, the market position of Panamax dry bulk carriers with relatively large deadweight tonnage is closely followed by (Super) handy size dry bulk shipping. At that time, the internal risk to the dry bulk shipping market was mainly due to the transfer of the capsize dry bulk shipping market segment to the Panamax type and (super) handy size type dry bulk shipping market segments. The Zika virus epidemic, as a typical public health emergency in noncore supply and demand countries of world trade, has a relatively low impact on world trade. As reflected in dry bulk shipping, it mainly acts on the supply side of both sides of trade demand and has a relatively limited impact on Brazil’s iron ore trade.During the period of analysis of the COVID-19 pandemic, the BCI index was negative for the first time in history; that is, capsize dry bulk shipping was not profitable during that period. In addition to the seasonal impact, the main reason is the sharp reduction of international demand. China is one of the major demand countries for ’s iron ore trade, the demand for which dwindled considerably during COVID-19. Accordingly, Brazil, as one of the main suppliers of iron ore trade, was affected by the pandemic, and the delivery recovery was slow. Compared with the same period, Brazil’s grain exports also decreased by 11% in January and February 2020. The capsize shipping market is still in the doldrums, but market demand has been maintained. The smaller Panamax, Super Handysize and Handysize ships recovered relatively more quickly from the loss of freight rates. According to the data, the Panamax dry bulk shipping market segment, as the net spillover part of risk fluctuation, transfers risk to the capsize and (super)handy size dry bulk shipping market segment fluctuation during the period of analysis. The COVID-19 global public health emergency not only acts on the main suppliers of international trade but also affects the principal demand sides, impacting both the supply and demand of international trade, the dry bulk shipping market and related enterprises.Considering the risk volatility spillover between two segments of the dry bulk shipping market, During the Zika epidemic, the transportation structure of dry bulk cargo did not change. The strength and direction of risk transmission are highly consistent with the volume of goods. Through the analysis of the risk transfer framework of two typical public health emergencies, we can draw the following conclusions:With the development of globalization, the relationship between the ship type market segments of the dry bulk shipping market is closer, and the degree of risk spillover is higher.When public health emergencies affect only individual nodes of global trade, especially the nonunique supply side, the impact of public health emergencies on the dry bulk shipping market will not affect its transportation structure. The main risk volatility spillover chain reaction is: capsize, Panamax and (Super) Handysize.When public health emergencies affect the whole process of global trade, especially regarding nodes with high demand, the dry bulk shipping market will affect the transport structure under the impact of public health emergencies. The market of the Capsize dry bulk carrier with high carrying capacity and low marginal costs will be greatly affected, and its cargo-carrying function will be replaced by a relatively more efficient small carrier with low cargo demand in the short term. In the beginning, the risk transferred rapidly to the Capsize shipping market and then mainly exports from the Panamax ship market to the (Super) Handysize ship market and the Capsize shipping market.In this paper, we find that the supply and demand of the dry bulk shipping market are impacted by the COVID-19 public health emergency. Public health emergencies have a strong impact on dry bulk shipping directly or indirectly from the perspective of policy constraints and the global industrial supply chain. The research shows that the impact of a certain period will reach the maximum on the third day, after which it will gradually decrease as the pandemic comes under control, and the impact will last for more than three weeks.Different types of public health emergencies have different impacts on the dry bulk shipping market due to their different areas of influence. The economic status of capsize dry bulk carriers will be affected by the "big event”, and the efficiency of smaller Panamax dry bulk carriers will be improved. Therefore, dry bulk shipping enterprises should accurately grasp the development direction of public health emergencies, accurately study and judge the types of events, reasonably carry out business and organize distribution and ship allocation.The pandemic will not disappear. With the further development of the pandemic, the future perspective will focus more on exploring the opportunities and challenges of the global shipping industry and trade structure in the later stage of public health emergencies.For dry bulk shipping companies, the most important thing is to make a quick judgment when public health emergencies occur, determine the speed of the spread and control the situation. First, we fully respond to the regional and knock-on effects of public health emergencies, summarize, and analyze the impact of world trade and customs clearance efficiency to judge whether it will impact the transportation structure of the dry bulk shipping market.While making a good market estimation, it is important to adjust the business according to whether it will affect the dry bulk shipping structure. When the impact of public health emergencies is small and controllable or occurs in nonunitary supply markets and secondary demand markets (hereinafter referred to as "minor events"), dry bulk shipping enterprises should strengthen the management of corresponding regional routes. Flexibly adjusting transport capacity and reducing the loss of capital and income also reduces the risk of becoming the medium of transmission. When public health emergencies are strong and uncontrollable or occur only in producer countries of the means of production and the main demand side of trade (hereinafter referred to as "major events"), dry bulk shipping enterprises should quickly integrate market information, analyze the future market volume of bulk commodities and other information, and design a good distribution plan in advance. At the same time, plans should be made for possible crew shortages and becoming isolated islands at sea to eliminate having to passively accept the situation when public health emergencies occur.In response to external risk input at the same time, dry bulk shipping enterprises should control internal risk transfer, avoid a strong impact on enterprises’ internal business between the development of the implicated role and affecting business revenues of the whole enterprise. According to the above analysis, when faced with "small events", risk transfer generally follows the principle that volume determines risk. In this situation, we should do a good job of splitting the internal business, controlling cash flow, reducing cash flow losses of damaged business, and minimizing losses. When facing "big events", enterprises should be prepared for the sudden reduction of cargo volume and the transformation of economic ship type. In the business planning of route ship allocation and ship cabin allocation, we should carry out the work of small ship types to large ship types, try to balance profits and losses by minimizing the reduction of the small ship market and help enterprises tide over the difficulties.In addition, from the perspective of enterprises, we can also make full use of the hedging forecasting tools of financial markets. By means of financial risk prediction, we can enhance the sensitivity of enterprise risk prediction and avoid risks in shipping financial markets in advance.The government should strengthen plans, ensure the transparency of public health emergency information to the greatest extent possible, help the market establish and improve emergency early warning mechanisms and shorten response times.The government should refine financial markets while reasonably controlling speculation, increase support for risk-averse financial products, establish and improve "rescue mechanisms", and help different subjects in sudden public health crises reduce the risk of capital chain ruptures.On the premise of respecting the main role of the market, the government should strengthen guidance, develop warning and guiding standards for the rational allocation of global shipping capacity, and strive to create a dynamic and reasonable capacity pool stock.The government should improve shipping laws and regulations, improve the good operation of shipping enterprises to safeguard their legitimate rights and interests and deal with the aftermath of bankruptcy according to the law and the stable mechanisms of market access, and effectively carry out standardization and supervision.


During the service period of a prestressed concrete bridge, as the number of cyclic loads increases, cumulative fatigue damage and prestress loss will occur inside the structure, which will affect the safety, durability, and service life of the structure. Based on this, this paper studies the loss of bridge prestress under fatigue load. First, the relationship between the prestress loss of the prestressed tendons and the residual deflection of the test beam is analyzed. Based on the test results and the main influencing factors of fatigue and creep, a concrete fatigue and creep calculation model is proposed; then, based on the static cracking check calculation method and POS-BP neural network algorithm, a prestressed concrete beam fatigue cracking check model under repeated loads is proposed. Finally, the mechanical performance of the prestressed concrete beam after fatigue loading is analyzed, and the influence of the fatigue load on the bearing capacity of the prestressed concrete beam is explored. The results show that the bridge prestress loss characterization model based on the POS-BP neural network algorithm has the advantages of high calculation efficiency and strong applicability. At present, although some progress has been made in the research of bridge prestress, most construction enterprises have some problems in the process of loss and analysis of bridge prestress under fatigue load. With the development of intelligent technology, the research on the mechanical and bearing capacity of building bridges has also been developed rapidly. In addition, in the modeling and analysis of the bearing capacity of bridge buildings, the advantages of the prestressed design of bridges under fatigue load based on cloud computing technology and intelligent algorithm are more obvious. The development of these technologies also provides opportunities for the research on the combination of the prestressed design and ultimate load performance of the bridge under the action of building stability and fatigue load . TherefoThis paper studies the application of bearing capacity and mechanical performance analysis model in the optimization of bridge prestress design under modern fatigue loads and is mainly divided into five sections. PSO-BP neural network algorithm is a multilayer feedforward network trained by error backpropagation algorithm, which is one of the most widely used neural network models. PSO-BP neural network algorithm is different from the conventional algorithm, which is a better multiresource control and calculation strategy . At presAt present, the PSO-BP neural network algorithm is widely used in the optimization analysis of the mechanical properties of materials. In the mechanical property analysis system for different types of bridge buildings, most of them are based on the PSO-BP neural network algorithm for approximate simulation solution . The objf(x) in this process is as follows:x is the prestress load, and h(x) is the expression of neural node factor:The traditional analysis method of bridge prestress performance is based on the classical Newton mechanics principle, which cannot carry out the visual overall simulation analysis of its stress process . Therefoη is as follows:The adaptive analysis model can realize the unified management of the basic parameter information source of bridge prestress under different types of fatigue load, the local difference analysis of bridge prestressed mechanical properties under fatigue load is realized, and the coupling coefficient w(x) is as follows:Then, the PSO-BP neural network algorithm is used for intelligent control and feedback correction, so as to realize the analysis of bridge prestressed mechanical properties and data storage under different types of fatigue load. After completing the above basic mechanical performance analysis, according to the collection process of ultimate load performance analysis data of bridge prestress under different types of fatigue load, the vector differences in the eigenvalues of different data, and the structural characteristics of the data, the matrix difference and other different characteristic description values are analyzed; the corresponding characterization function Then, the intelligent optimization process and deep mining process based on PSO-BP neural network algorithm are used to realize the mechanical and ultimate load performance analysis and law analysis of bridge prestress under fatigue load in different types and different structural design methods. The finite element simulation analysis process of bridge prestress under fatigue load is shown in PSO-BP neural network algorithm is used to analyze the mechanical properties of bridge prestress under different fatigue loads, eliminate redundant data, extract effective information, classify data and optimize storage strategy, which is the necessary process of the experiment, and achieve the height classification according to the similarity degree in the design of ultimate load of the bridge prestress under the fatigue load. The data collection, information mining, and feature extraction of different ultimate load performance analysis data are realized. When the mechanical performance analysis data of the bridge prestress under repeated fatigue load are reused or the invalid information is analyzed repeatedly, the feedback control strategy of PSO-BP neural network algorithm will be adopted to control the different types of data information according to the known absorption coefficient requirements. Then, the process of collecting the effective data, feature classification, extracting mechanical information, and quantitative characterization of the bridge prestress under fatigue load is completed. The corresponding data reference range is shown in The operation analysis process of its performance is shown in f(x) in this process isIn the first step, in the process of analyzing the mechanical properties of the bridge prestress under the fatigue load of known types and structural shapes, there is often a problem that the error is too large in the process of analyzing the mechanical properties of the bridge prestress under the fatigue load due to the deviation of the discrete neural network algorithm in setting the standard mechanical parameters. Therefore, in the analysis process of the bridge prestress under the fatigue load with known type, structure shape, and thickness information, combined with the classical strategy analysis method based on traditional Newton mechanics, the PSO-BP neural network algorithm is used. Based on the random data eigenvector generated in the bridge prestress database under fatigue load collected by the finite element simulation system, the problem of large mean square error of bridge prestress under different types of fatigue load is solved by hierarchical closed-loop regulation . The judIn order to solve the problem of low cooperation efficiency in the distributed calculation of PSO-BP neural network algorithm for the collection, processing, and classification of bridge prestress data under fatigue load, this study combines the mechanical performance analysis idea based on neural network algorithm and particle swarm optimization algorithm. By simulating the “multiple PSO neural node operation network” in the process of “neural node transfer” modeling and drawing, the evaluation basis of the mechanical performance analysis efficiency of bridge prestress under fatigue load is constructed, so as to realize the performance analysis and result storage of bridge prestress under different fatigue loads. The simulation analysis results are shown in y. The corresponding basic strategy function p(x) is as follows:In the second step, when the mechanical and ultimate load performance analysis model analyzes the corresponding datasets of bridge prestress under different fatigue loads, its ultimate load and prestress data identification rules will attribute the unknown data information to the same data cluster group according to the corresponding mechanical eigenvalues. When the characteristic values of any two data cluster groups in the data of bridge prestressed mechanical performance analysis under different types of fatigue load are different, it means that the characteristic information of the two kinds of data is greatly different. When the mechanical performance analysis model is used to analyze and solve the ultimate load of bridge prestress under different fatigue loads, the selection of eigenvector is limited by the stability, and its modulus length is determined by the modulus length of eigenvector y needs fitting analysis to know the stability effect of the mechanical property analysis model. Therefore, the equation needs to be optimized and decoupled. The fitting analysis function isThe selected eigenvector l(x) before compensation isIn the third step, in the process of mechanical and ultimate load performance analysis of bridge prestress under different fatigue loads, it is necessary to carry out targeted compensation for the placement characteristics of bridge prestress under different types of fatigue loads. The mechanical analysis function l′(x) after compensation isThe mechanical analysis function e(x), r(x), and u(x) areWhen the differential evolution strategy is used to analyze the mechanical properties of different datasets, three common mechanical properties analysis rules will be randomly selected. The three analysis rule functions The PSO-BP neural network algorithm used in this study is a discrete PSO-BP neural network algorithm. The basic steps of the analysis of the mechanical properties of bridge prestress under fatigue load are as follows.Among them, different data structures will be obtained under different rules of mechanical properties and ultimate load effect analysis. In order to extract the characteristics of different types of mechanical data and analyze effective data, it is necessary to simulate the prestressed stress of the bridge under these different types of fatigue loads on the mechanical and ultimate load levels . The oveThe innovation of this paper lies in the application of neural network algorithm and bearing capacity design idea to the modeling and analysis of bridge mechanical properties. On this basis, we can make full use of the basic information and characteristic parameters of bridge prestress under different types of fatigue load in Internet database. The unified mechanical performance analysis of bridge prestress under fatigue load is realized. The similarity degree between the comparison columns  and the reference columns  and the agreement degree of the expected index (the effective data of bearing capacity level) are quantitatively described by the characteristic coefficient. The quantitative index is used to sort the influence degree of the efficiency of the bridge prestressed ultimate load performance analysis model under fatigue load, which can effectively realize the optimal control and ultimate load design of the bridge prestressed under different types of fatigue load through different control methods.In order to study the deflection and flexural stiffness degradation of the prestressed concrete structure under fatigue loading after cracking, FTG-3 and FTG-4 beams were subjected to 2 million constant-amplitude fatigue loading tests and the crack growth at the cracks of the beams was observed. Through the formation of new cracks and the deflection of model beam, the development rules of mid-span deflection, steel strain, and concrete strain, as well as the corresponding crack width and strain amplitude under fatigue load, are studied and analyzed. In the experiment, the experimental objects involved in this study are the samples of the bridge prestressed optimization design under the fatigue load of different types of structures. It can quickly collect, analyze, extract, transform, and store the mechanical and ultimate load performance of the bridge prestressed under fatigue load . By analyzing other characteristics of prestress under different structural fatigue loads, different ultimate load characteristics are obtained. And cloud records are obtained, so as to achieve high-precision performance simulation. Then, based on the analysis of mechanical properties, the ultimate bearing capacity of prestressed bridge under different types of fatigue load is achieved. The experimental data are shown in In this way, in the follow-up process of big data analysis, we can query, call, and determine the ultimate load scheme with high accuracy and high efficiency , so that under the big data collection and storage system, the, To achieve the accurate distribution of bridge prestress design process under each fatigue load, improve the integrity of the ultimate load analysis and prestress loss determination. The preliminary experimental analysis results of the bridge prestress loss determination model under the fatigue load are shown in The experimental group is the bridge prestress change and loss under different fatigue loads, and the control group is the bridge prestress of different types of the same structure and the same type of different structures under fatigue loads with known ultimate load effect data. The error of the intelligent optimization design model is analyzed by the experimental process of ultimate load optimization and three groups of known ultimate load performance parameters. The error is shown in The experimental data analysis results of the experimental data are shown in It can be seen from in The traditional fatigue load has some problems such as bad ultimate load effect and poor mechanical performance. Based on this, this paper designs the mechanical and ultimate load performance analysis model based on PSO-BP neural network algorithm and studies the process of prestressed design and mechanical performance modeling of bridge under the action of modern fatigue load based on ultimate load. The paper analyzes structural stability, mechanical performance, ultimate load effect, and external aesthetic feeling of the prestressed bridge under the action of conventional fatigue load. The mechanical properties of the prestressed bridge under different fatigue loads are evaluated by using the finite element simulation strategy, and the method can realize adaptive modeling of the mechanical properties and ultimate load effects of the bridge prestress under the fatigue load and realize the diversified analysis and aesthetic design. Finally, the mechanical properties and the application effect of ultimate load of the bridge prestressed under different fatigue loads are analyzed by combining the known characteristics of bridge building and designing the relevant experiments. The experimental results show that the mechanical performance analysis model based on PSO-BP neural network algorithm has the advantages of high calculation efficiency and good mechanical performance simulation effect and can play an effective role in the design of bridge prestress under fatigue load. But this study only considers the loss determination, mechanical properties, and ultimate load effect analysis process of bridge prestress under the action of modern fatigue load and does not consider its reliability factors in other aspects, so deep optimization research can be carried out.


The Journal and Authors retract the 8 February 2021 article cited above for the following reasons provided by the Authors:Following publication, concerns were raised regarding the integrity of the images in the published figures. The authors failed to provide a satisfactory explanation during the investigation, which was conducted in accordance with Frontiers’ policies.This retraction was approved by the Chief Editors of Frontiers in Oncology and the Chief Executive Editor of Frontiers. The authors agree to this retraction.


Today many older adults are experiencing intensified social isolation and loneliness as they attempt to “stay safe at home.” The notion, is a stark contrast from our understanding of the importance of social connections on health and well-being. This session highlights: first hand experiences caring for older adults during the COVID-19 pandemic and the implications of social isolation on the health of older adults. The speaker will offer perspectives for ESPO members on the role of community engagement in orienting research agendas, both now (amid the pandemic) and into the future.


The shortage of health care providers (HCPs) and inequity in their distribution along with the lack of sufficient and equal professional development opportunities in low-income countries contribute to the high mortality and morbidity of women and newborns. Strengthening skills and building the capacity of all HCPs involved in Maternal and Newborn Health (MNH) is essential to ensuring that mothers and newborns receive the required care in the period around birth. The Training, Support, and Access Model (TSAM) project identified onsite mentorship at primary care Health Centers (HCs) as an approach that could help reduce mortality and morbidity through capacity building of HCPs in Rwanda. This paper presents the results and lessons learnt through the design and implementation of a mentorship model and highlights some implications for future research.The design phase started with an assessment of the status of training in HCs to inform the selection of Hospital-Based Mentors (HBMs). These HBMs took different courses to become mentors. A clear process was established for engaging all stakeholders and to ensure ownership of the model. Then the HBMs conducted monthly visits to all 68 TSAM assigned HCs for 18 months and were extended later in 43 HCs of South. Upon completion of 6 visits, mentees were requested to assist their peers who are not participating in the mentoring programme through a process of peer mentoring to ensure sustainability after the project ends.The onsite mentorship in HCs by the HBMs led to equal training of HCPs across all HCs regardless of the location of the HC. Research on this mentorship showed that the training improved the knowledge and self-efficacy of HCPs in managing postpartum haemorrhage (PPH) and newborn resuscitation. The lessons learned include that well trained midwives can conduct successful mentorships at lower levels in the healthcare system. The key challenge was the inconsistency of mentees due to a shortage of HCPs at the HC level.The initiation of onsite mentorship in HCs by HBMs with the support of the district health leaders resulted in consistent and equal mentoring at all HCs including those located in remote areas. Globally, maternal mortality remains unacceptably high. In 2017, 295 000 women died during or following pregnancy and childbirth (approximately 810/day). The vast majority of these deaths occurred in low-resource settings and most could have been prevented . About tA significant number of maternal and newborn related deaths in LMICs are linked to the shortage of qualified Health Care Providers (HCPs) who are needed to provide quality prenatal care, skilled birth attendance and emergency obstetric services - interventions crucial to reducing maternal and perinatal deaths , 5. ThisSeveral studies have revealed that didactic training does not effectively translate knowledge into practice to address system-level barriers , 12. HowRwanda has made great strides in the area of women’s and children’s health over recent decades including the attainment of Millennium Development Goals (MDGs) 4 and 5 –20. DespTo address high morbidity and mortality rates likely due to insufficient competent HCPs in the health facilities, the TSAM project designed and implemented mentorship programmes in HCs as a way of strengthening the continuum of care while also building the capacity of HCPs to be able to deliver high-quality care during the perinatal period. TSAM for MNCH is a project with funding provided to the University of Western Ontario (Western) by Global Affairs Canada (GAC). TSAM’s mission is to improve Maternal, Newborn and Child Health (MNCH) in Rwanda by working with local partners to improve health service access and delivery.Although there is the need to develop and implement effective models to train HCPs, there were no broad-based models for mentoring in the health centers in Rwanda. Furthermore, we believe that the model we developed based on making use of the midwives from District Hospitals (DHs) that were given extensive mentoring by an interprofessional group of experts from tertiary hospitals, to provide mentoring at the health centers in their hospital catchment area has not been used elsewhere in resource-poor countries . This paper aims to describe the development, implementation as well as results of the mentorship model for HCPs providing maternal and neonatal care in 68 health centers of the 3 districts of the Northern Province of Rwanda. The indicators that were assessed for the results included the distribution and consistency of mentoring to the catchment areas of all of the DHs included in this project. The data on the initial assessment of the study locations were also analysed.The 68 HCs involved in this study were located in Rulindo, Gicumbi and Gakenke districts in the Northern Province of Rwanda. The onsite mentorship programme was implemented by TSAM project and its stakeholders in the HCs in the three districts. These 3 districts were assigned to the TSAM project as per the Memorandum of Understanding between the project and the Ministry of Health. This research describes the mentorship programme. The design phase of this programme started with an initial assessment of the status of training in HCs in these districts. The results of this assessment informed the selection of midwives to serve as Hospital-Based Mentors (HBMs) for health care providers at the HCs. The research further describes the other steps of the design phase, namely the refresher courses on Emergency, Obstetric Neonatal Care (EmONC) for selected Hospital Based Mentors and training on the mentoring approach to be adopted. These HBMs also benefited from other courses with cross-cutting themes such as ethics, inter-professional collaboration, gender, maternal mental health and Gender-Based Violence (GBV). The initial training makes this mentorship programme unique, as the additional training was designed to allow HBMs to manage the mothers and newborns in an integrated manner. In addition, HBMs were drawn from the mentees who had followed the mentoring programme at the respective hospitals under the same project framework. Upgrading of some mentees to HBMs through cascades of special training presents the second unique aspect of our mentorship programme. The fact that mentors were drawn from a cadre of DH mentees allowed them to conduct mentorship more effectively.The design phase involved information meetings to establish a clear process for engaging all stakeholders and to ensure ownership of the model. Following the initial assessment and training, 23 HBMs conducted monthly visits to the 68 HCs located in catchment areas of five TSAM assigned hospitals in North for 18 months, from October 2018 to March 2020. This model was extended later in other HCs located in the catchment area of 5 hospitals in the Southern Province. Participants to the mentoring programme described in this manuscript were nurses or midwives providing maternal and/or neonatal care in 68 HCs of 3 concerned districts in the Northern province.Data on the number of mentees who attended the mentorship programme during its lifetime as well as the data on the initial assessment were analysed for this study. The data were entered in a database designed for the project using Excel. Analysis was done in Microsoft Excel to generate tables and descriptive statistics. Locations of HCs were collected using Global Positioning System (GPS) devices and the coordinates were used to generate maps in ArcGIS 10.7. The geographic data were analysed to identify spatial disparity of midwives using data on the number of midwives and population density for each hospital catchment area. Population data were obtained from the Health Information System of the hospital. In addition, data were analysed according to the number of nurses and midwives in the health centers that had received training on EmONC. Mentoring data was collected on the number of mentoring visits in the DH catchment areas segregated by gender for the nurse and midwife mentees. Also, data on the number of mentoring visits were collected based on the professional qualification of the midwives and nurses.Prior to designing the mentoring programme at the HC level, a rapid assessment in health facilities located in TSAM-assigned hospitals was conducted by researchers working on the project. The assessment aimed to determine the availability of staff who provide MNH care and the status of training on MNH for those staff. The results of the assessment allowed the project and its stakeholders not only to know the number of mentees that would be available but also it informed the initial selection of competent hospital-based mentors (HBMs). This assessment was conducted cognizant of the fact that over the past 2 decades, HCPs have received some off-site training related to maternal and newborn care , 19, 21.The results revealed that efforts are being made to equip maternity departments of HCs with midwives. Of the 68 HCs located in the catchment area of TSAM-assigned hospitals, 43 (63 %) had at least one midwife by the time of the assessment. However, as seen in Fig. Apart from the availability of midwives in the HCs, the assessment revealed that there is an inequity in terms of densities of health care providers who benefited from the training on the EmONC across hospital catchment areas and districts. As shown on Fig. The initial assessment also allowed the project and its stakeholders to examine the spatial distribution of HCPs with additional training on Essential Newborn Care (ENC). As with the EmONC, there were geographical disparities with HCPs trained in ENC which is thought to be helpful for staff providing care to mothers and newborns Fig. .Fig. 3SMentorship is a flexible teaching and learning process that serves specific objectives of the HCPs and health care services –15, 21. The mentorship model was implemented by HBMs who were midwives practicing in the DHs responsible for oversight of the HCs. The majority of these midwives had been mentored in a separate programme for HCPs at the DH level by national mentors with the support of the same project . PotentiThe mentorship model development consisted of several phases. The first was providing a refresher course on Emergency Obstetric and Newborn Care (EmONC) for 25 potential mentors. The candidate HBMs was proportional to the number of HCs within the catchment area of each hospital. The second phase consisted of providing training in mentoring and Cross-Cutting Themes (CCTs) including Gender, Ethics and Inter-Professional Collaboration to successful candidates to EmONC refresher training. Thirdly, there were induction meetings held for each DH to introduce the programme and ensure it is owned by beneficiaries. The final phases were the implementation of the onsite mentorship visits followed by monitoring and evaluation activities. Once again, it is worthy to mention that HBMs were drawn from former mentees.After a successful design phase, each HBM was assigned to between 2 and 3 HCs. The mentorship field visits were organized for all 68 HCs in the Northern Province. One-day monthly visits were conducted by HBMs from October 2018 to March 2020 (18 months). During the mentoring period, key services areas mentored include the labor ward, post-natal care and antenatal care services. Activities carried out by HBMs include management of cases with the mentees, bedside teaching, presentation on key selected topics in morning staff meetings based on the needs, and training of mentees using simulation. Logbooks were used to track the participation of mentees in different mentorship activities. The topics covered by HBMs were the components of Essential Newborn Care (ENC) and those of EmONC. HBMs had benefited from refresher courses on these topics to be covered. During the mentorship period, different activities were completed by mentors and mentees including ward round, assisted delivery, newborn resuscitation, and post natal care. In addition, mannequins were used to teach skills for different components. Upon completion of each of the visits, reports were written and submitted to the director of nursing at each hospital for compiling the report at the hospital level.The overall coordination of the mentoring programme was done by a CPD programme manager within the TSAM project. The formats of the reports by the mentors were developed by the TSAM project CPD team and presented during both the training on mentoring and induction meetings. The completed reports were then submitted to the CPD manager for the TSAM project to be compiled and analyzed and a report prepared.To ensure that the mentorship model was implemented as designed and experiences were shared, bi-annual evaluation meetings were organized for each hospital. These meetings brought together the same participants as those who attended the induction meetings before initiating the mentorship in HCs. The monitoring meetings aimed to share the key messages from the report of the mentorship visits, discuss the successes and challenges of the mentorship visits as well as develop the strategies to overcome the challenges. The key points that emerged from the coordination meetings are summarized below: The mentoring programme is helping to significantly improve the quality of care in health centers, this was mentioned based on the way HCs appreciated the improvement of the knowledge and skills of HCPs.The mentoring programme is conducted the way it was designed.The mentoring programme is different from any other form of supervision at the HC. This is because mentees realized that mentors are not supervising what they are doing but that they are working together while providing feedback. They were used to supervisors where the later come to evaluate only what they did.Mannequins were distributed to all HCs to enhance the knowledge co-sharing by the mentorship programme using simulation to achieve its goals.There is a need to strengthen the consistency of mentees during the mentorship visits. The fact that some mentees have not been consistent due to the shortage of HCPs was mentioned here as one of the key challenges.From October 2018 to March 2020 (18 months), each of the 68 HCs located in the catchment area of 5 hospitals in Rulindo, Gicumbi and Gakenke benefited from mentorship monthly visits  [Analysis of the results of the programme indicated that the mentorship training programme led to equity in the capacity of HCPs regardless of the location of the health center. One hundred and forty-six (146) HCPs took part in 6 or more mentorship visits, translating into an average of 2 mentees who completed at least six visits per HC. Looking at the consistency of mentoring and taking into account the discussion with all involved people during the coordination meetings, mentorship of HCPs has potentially improved their skills and performance at all levels of the health system. This is consistent with the findings of studies that evaluated this mentorship programme and which revealed that the mentorship improved the knowledge and self-efficacy of health care providers in managing PPH and newborn resuscitation in Rwanda , 25. Acc = 0.58) . These f = 0.58) –15, 21.The current successes of the TSAM project’s onsite mentorship model demonstrate the practicability of rapidly implementing a provider-centered mentorship programme that will deal with the quality of care and equity at both the individual and structural levels at the district level. Mentorship training, thus, has the potential to enhance the skill level of health care workers and improve the quality of care provided in rural Rwanda. In India, Jayanna et al.  found thOnsite mentorship programmes can ensure equity in access to skilled service providers and quality health care because it offers training tailored towards the trainee’s work situation. Thus, mentorship differs from in-class didactic training. This means that HCPs are trained where they are and in what they do, thus improving quality and equity in the number of skilled people in rural areas. In Rwanda, where, despite the achievement of the MDGs on maternal health care, disparities in the use of health services and quality of care still exist , 27), suAn additional component of a successful mentoring programme at the HCs is coordination at the district level. The TSAM programme managed this by having the mentor complete reports and after compilation and analysis, the report was shared with the hospital management team for action in case any issue was identified. It is part of supporting the DHs and their mandate to support the HCs in the mentoring programme. This is direct feedback to the management team at the DH and it supported the project efforts to be collaborative by making certain that the DH management team is aware of the experiences of the mentors. Another important factor is the involvement of Directors of Nursing in the supervision of the mentoring programme. Given the benefit of the TSAM onsite mentoring programme and similar ones such as the Mentoring and Enhanced Supervision at Health Centers (MESH) and their potential to further reduce maternal and neonatal deaths in Rwanda during the era of the Sustainable Development Goals (SDGs), there is a need to mainstream and regularize this model into the health care system. Mainstreaming this onsite model into the health delivery systems is especially useful in resource-poor settings where there are shortages of specialized health workers. Not only will this ensure that health care workers are up to date with the current trends in their fields, but it will also increase job satisfaction and lead to better performance and retention of skilled workers in rural areas, cognizant that job satisfaction is an important determinant of job retention . It is wDespite the demonstrated benefits of the mentorship programme, some challenges must be overcomed if the programme is to be effectively integrated into the mainstream health system of the country. These challenges include the limited number of HCPs in health centers and more importantly in hospitals where the mentors are working which does not allow mentoring a big number of mentees at the same time, lack of some essential equipment at health centers and the staff turnover . MeanwhiIn summary, after a year and a half of implementing the onsite mentorship in health centers, there has been equity in the number of skilled personnel in EmONC and ENC in the Northern Province of Rwanda. All health centers were reached monthly and disparities and inequities in terms of capacity building were avoided. We conclude that the programme generated a good number of mentees who have been consistent and trained by HBMs who were drawn from the former mentees with the hope that this will improve significantly the quality of care to women and newborns in Gakenke, Gicumbi and Rulindo districts. However, very close monitoring and coordination of the mentoring including regular supervision and feedback as well as the engagement of leaders at the facility level are key to success. The strategy to strengthen knowledge retention is required for the sustainability of the gains.Researchers in the field of CPD for HCPs in primary health care facilities should consider researching job retention of mentees after some period of mentoring. The cost-effectiveness of the onsite mentorship should also be considered to compare the classic training and the onsite mentorship. Finally, researchers should examine whether onsite mentorship enhances job satisfaction and job retention among HCPs.


The geriatric population is rapidly growing, and this growth is beyond the pace of increase in the number of healthcare professionals who are qualified to care for and tend to the various needs of this significant subgroup of the population. The current university curricula have not been sufficient in terms of quantity as well as their ability to address the ageism inherent in the perspectives of students from across the educational spectrum. In recognition of the absence of standardized geriatric guidelines, medical associations across Canada and the United States have established geriatric learning competencies for medical programs. Nevertheless, there are exiting gaps regarding the development and evaluation of geriatric-focused didactic programs that adequately train and build competency among the students interested in pursuing careers with geriatric-specific elements. A university-wide program was developed to enhance aging education and build competency through sparking interest, providing better education related to aging, and building better relationships between future healthcare professionals and older adults. To evaluate the impact of this program, a logical framework was developed a-priori and revised through constant iterations and following discussion with the program’s multidisciplinary stakeholder group. Quantitative measures are being augmented with in-depth qualitative interviews to explore elements influencing students’ experiences with the program and the effect on their interests in and attitudes towards geriatrics. The results will inform our conclusions regarding program effectiveness in enhancing interest in geriatric-focused education among the students and trainees and assist with recommending future directions regarding impact and large-scale dissemination and implementation.


About one third of food produced for human consumption is lost or wasted. For this reason, food losses and waste has become a key priority within worldwide policy circles. This is a major global issue that not only threatens the viability of a sustainable food system but also generates negative externalities in environmental terms. The avoidance of this forbidding wastage would have a positive economic impact on national economies in terms of resource savings. In this paper we look beyond this somewhat traditional resource savings angle and we shift the focus to explore the distributional consequences of food losses and waste reduction using a resource constrained modeling perspective. The impact due to the behavioral shift of each household is therefore explained by two factors. One is the amount of resources saved when the behavioral shift takes place, whereas the other one has to do with the position of households in the food supply chain. By considering the whole supply chain, instead of the common approach based only in reducing waste by consumers, we enrich the empirical knowledge of this issue and improve the quantification of its economic impact. We examine data for three EU countries that present different economic structures  so as to have a broader and more robust viewpoint of the potential results. We find that distributional effects are different for consumers and producers and also across countries. Our results could be useful for policymakers since they indicate that policies should not be driven merely by the size waste but rather on its position within the food supply chain. Food losses and waste (FLW) means that food itself and all the resources and sink capacities employed along food supply chain (FSC) are wasted. FLW have adverse impacts on environmental and socioeconomic terms with differences between high- and low-income nations . On one FLW occurs at different stages of the FSC, so identifying the most effective points for governance instruments is of the major importance to tackle this problem . Food loFLW has become a key priority within the worldwide policy circles, being particularly pertinent in the light of the Sustainable Development Goals (SDGs) of the UN, adopted in 2015 as part of the Agenda 2030. This includes Goal 2 ‘end hunger’ and Goal 12 ‘responsible consumption and production’. Under the latter, target 12.3 explicitly requires “halving per capita global food waste at the retail and consumer levels by 2030 and reduce food losses along production and supply chains, including post-harvest losses”. In fact, it has been estimated that halving food waste could meet the demand for food of the growing population. To track the progress towards targets 12.3, FAO has developed two indices (Food Loss Index and Food Waste Index). First results have been released in December 2019. However, considerable data challenges in developing these indices still remain [In the same vein, the EU has placed reducing FLW among its top priorities. Already in 2011, the European Commission identified the food sector as key sector in its Roadmap to a Resource Efficient Europe. The reduction of food waste was also a targeted area of the EU action plan for the Circular Economy launched in 2014 . Then, tNotwithstanding that SDG has put FLW back on to the worldwide political agenda, the evidence to inform policymakers on the magnitude, causes, remedies and impacts of FLW remains extraordinarily sparse . Within This work looks further into the distributional consequences of FLW reduction by using a CGE framework. It has the capability of capturing the economic impact of reallocating those resources saved by reducing FLW along the FSC in some EU countries. To do so, we implement budget constrained expenditure multipliers  using a A Social Accounting Matrix (SAM) is the most common reference database for the implementation of the Computable General Equilibrium (CGE) framework, providing data for economic modeling but also a complete and intuitive structural snapshot of the economy under study. The concept of a circular flow of income, underlying a SAM, means that the database reflects the full process of production, trade, income generation and its redistribution between institutional sectors . This alThe structure of the SAM database is a square matrix in which each account is represented by a row and a column. Transactions are recorded by double entry bookkeeping system of accounting, with income in rows and payment in columns. There are six basic groups of accounts, representative of activities, commodities, production factors and institutional sectors . The final dimensions of the matrix are determined by the level of disaggregation of these groups .AgroSAMs is a set of standardized SAMs with disaggregation of the primary sector for each Member State, providing directly comparable structural information for each economy. These follow the same sectoral concordance as the Eurostat Supply and Use Table, with the exception of the agriculture and food accounts drawn from CAPRI database . Thus, oThere are several studies that present estimates of FLW generated at EU level using various data sources, resulting in different figures for wasted food per capita . This raIn this study, the estimates of  are emplScenario 1: Impact on the member states economies analyzed as a result of reducing the avoidable FLW generated by the overall FSC.Scenarios 2 and 3: Impact of reducing the avoidable FLW in WRS and FSS respectively in terms of total output, GDP and employment on the three European economies.Scenario 4: Impact resulting of the abatement of the avoidable portion of food which ends up as being discarded by households in terms of total output, GDP and employment on Spanish, German and Polish economies.Considering the previous information, we put forward four different scenarios to assess the economic impact and the distributional effects of reducing avoidable FLW on the three member states selected:Z is the vector of exogenous accounts4F Amk represents how the income flows from the exogenous accounts are distributed among the endogenous accounts).m  usually depends on the type of analysis undertaken, which determines which accounts (exogenous) are the ones explaining the variation of the income in other accounts (endogenous). If changes in the vector of exogenous accounts are denoted as dZ, changes in the income of the endogenous accounts will be expressed asBased on the multiplier theory initiated by  and latethj column in M indicates the total income generated in each of the endogenous accounts when a unit of income flows from the exogenous institutions towards the j endogenous account. Adding up each column in M we obtain the standard multipliers The φ) that guarantees the upholding of the budget constraint of the corresponding agent Conversely, if a budget constrain is included in the model, any increase of income to an endogenous account will be followed by a reduction of income to the remaining ones, keeping thus that constraint . This imUnlike the always positive standard multipliers Z is defined for each agent along the supply chain and at household level, encompassing the corresponding demand of agrifood commodities. A new vector Z′ is obtained by subtracting the injection of income resulting of monetizing the avoidable portion of food waste by each agent along the supply chain and at a household level in each member state selected. According to [In this study, the exogenous vector rding to , food waUnder the Scenario 1 , the PolIn Scenarios 2 and 3, the portion of avoidable food waste established was the same (6.3% of food purchases) but the monetary size of the shock is quite different for each sector, such as the shock is much smaller within WRS than within FSS. In the case of WRS , GermanyThe size of the shock due to reducing food waste by German and Spanish FSS is much greater than in the corresponding WRS . For thoScenario 4 reflects the impact of reducing the avoidable food waste generated by HH . As pointrade-offs occur on the demand side where a reallocation of spending on previously wasted foods causes some producers to be worse off and some to be better off”. To the best of the authors’ knowledge, there are no further studies considering net effects of household behavioral shift. On the other hand, the impact of household food waste reduction is also analyzed by [investments to reduce food waste by manufactures could generate some efficiency gains from improved packaging and reductions in product losses which may even offer net benefits to those firms that uptake food waste reduction technologies base on [Nonetheless, available data does not allow an accurate quantification of these payoffs [The use of budget constrained multipliers allows a better understanding of the impact of FLW reduction on the selected economies. The money saved by such reduction is spent on other commodities following the initial pattern of expenditure of each agent. The impact due to the behavioral shift of each agent is explained by the amount of resources (money) saved but also by the position of each agent in the FSC and therefore the relationship of such agent with the remaining ones embodied within the AgroSAM. In this vein, the behavioral shift of household is of major importance as their decrease of demand of food means a reduction in the activity of all the previous agents along the FSC; while the money reallocated to other activities implies an increase in demand that should be meet with a rise in the production of such activities. These results are consistent with the economic theory of food waste and the results stated by , where tlyzed by  showing lyzed by  hypothes base on . Nonethe payoffs . Our tim payoffs ,60. FinaAccording to , economiFood waste reduction lessens the misappropriation of economic resources in a world that faces multiple challenges due to the increasing population growth. Wide economic impact of FLW reduction provides essential policy guidance to tailor interventions that target the prevention and reduction of FLW, including the complete FSC in order to become sustainable while improving food security and nutrition. Considering the whole supply chain instead of focusing only in reducing the waste by consumers, which seems to be the approach taken by most industrialized countries, the policies will have the greatest beneficial impact.We have used a SAM model in this research since this type of model has several advantages over other methodologies. They are very useful for impact analysis and provide sensible estimates of sectoral and economy wide impacts originating in a change in final demand. They are relatively easy to use and require only a modest amount of training for running the required software. In fact, the hardest question for researchers is the availability of data. When data are available, these methodologies enable the user to quickly conduct certain types of impact analysis. Nevertheless, in regard to further research, the development of a fully Computable General Equilibrium model based as well on a SAM database would provide a better platform for the dynamic representation of economic conditions over the medium and long term. This extension could facilitate a more holistic and complete framework to evaluate the economic impact of food waste reduction. Adaptation to changing market conditions and prices is also of paramount relevance for adequately capturing the behavior of economic agents.


Dystonia is a disabling movement disorder characterized by abnormal postures or patterned and repetitive movements due to co-contraction of muscles in proximity to muscles desired for a certain movement. Important and well-established pathophysiological concepts are the impairment of sensorimotor integration, a loss of inhibitory control on several levels of the central nervous system and changes in synaptic plasticity. These mechanisms collectively contribute to an impairment of the gating function of the basal ganglia which results in an insufficient suppression of noisy activity and an excessive activation of cortical areas. In addition to this traditional view, a plethora of animal, genetic, imaging and electrophysiological studies highlight the role of the (1) cerebellum, (2) the cerebello-thalamic connection and (3) the functional interplay between basal ganglia and the cerebellum in the pathophysiology of dystonia. Another emerging topic is the better understanding of the microarchitecture of the striatum and its implications for dystonia. The striosomes are of particular interest as they likely control the dopamine release via inhibitory striato-nigral projections. Striosomal dysfunction has been implicated in hyperkinetic movement disorders including dystonia. This review will provide a comprehensive overview about the current understanding of the functional neuroanatomy and pathophysiology of dystonia and aims to move the traditional view of a ‘basal ganglia disorder’ to a network perspective with a dynamic interplay between cortex, basal ganglia, thalamus, brainstem and cerebellum. Dystonia belongs to the group of hyperkinetic movement disorders that is characterized by abnormal postures or patterned and repetitive movements due to sustained or intermittent muscle contractions  in the vast majority of patients with dystonia , dystonic signs can most frequently be observed in SCA type 3 (Kuo et al. The traditional view on neural network organization encompasses distinct striato-pallido-thalamo-cortical and cerebello-thalamo-cortical pathways that convergently project to distinct thalamic nuclei and are only integrated at the neocortical level.This view has been challenged by the evidence of direct anatomical connections between basal ganglia and cerebellum in animals (Bostan et al. Evidence for a link between the cerebellum and the striatum on the neurotransmitter level derives from the observation that the activation of cerebellar and striatal glutamate receptors, specifically AMPA receptors, induced dystonia in animal models whereas AMPA antagonists reversed this effect and improved dystonia (Fan et al. The clinical key feature of dystonia is an insufficient suppression of undesired movements either during rest or during the execution of a certain task. New evidence suggests that striosomal dysfunction could result in dysregulated dopamine release in the substantia nigra causing an imbalance between the direct and indirect pathway that is associated with impaired inhibition and the occurrence of dystonic movements. This hypothesis, however, has to be proven in future studies. Furthermore, dystonia can no longer be regarded a disorder of the basal ganglia. Recent evidence indicates that the cerebellum is likewise involved in the pathogenesis and that strong interactions between the basal ganglia and the cerebellum are present not only under physiological conditions but also in dystonia Fig. . Disynap


High-resolution ultrasound is preferred as the first-line imaging modality for evaluation of superficial soft tissues, such as the facial muscles. In contrast to magnetic resonance imaging and computed tomography, which require specifically designated planes  for imaging, the ultrasound transducer can be navigated based on the alignment of facial muscles. Botulinum toxin injections are widely used in facial cosmetic procedures in recent times. Ultrasonography is recognized as a useful tool for pre-procedure localization of target muscles. In this pictorial review, we discuss the detailed sonoanatomy of facial muscles and their clinical relevance, particularly with regard to botulinum toxin injections. Furthermore, we have summarized the findings of clinical studies that report ultrasonographic imaging of facial muscles. High-resolution ultrasound (US) has emerged as one of the most convenient imaging tools for evaluation of superficial soft tissues ,2. Most Botulinum toxin injections are widely used in recent times for cosmetic dermatologic procedures involving the face ,7. US imIn contrast to other body parts, the subcutaneous layers of the face appear well organized. The superficial musculo-aponeurotic system (SMAS) refers to a fibrous network of inelastic tissues located deep within the subcutaneous tissues, with occasional investment into the underlying muscular layer ,10. SMASThe frontalis muscle originates from the galea aponeurotica (a layer of dense connective tissue that extends over the cranium) and is inserted into the orbicularis oculi muscle. It is innervated by the temporal branch of the facial nerve and receives its blood supply from the supraorbital and supratrochlear arteries. Contraction of the frontalis muscle raises the eyebrows and wrinkles the forehead .The transducer is initially placed in the horizontal plane at one fingerbreadth cranial to the eyebrow. The frontalis muscle covers the frontal bone and is visible beneath the SMAS A 5]. Th. Th5]. TAging is associated with the development of wrinkles over the forehead, perpendicular to the course of the frontalis muscle. Botulinum toxin injections relax the frontalis muscle and are therefore useful to minimize wrinkles . It is rThe temporalis muscle originates from the parietal bone of the skull and the superior temporal surface of the sphenoid bone and is inserted on the coronoid process of the mandible and retromolar fossa. It is innervated by the anterior division of the mandibular nerve and receives its blood supply from the deep temporal artery. Contraction of the temporalis muscle elevates and retracts the mandible .The transducer is initially placed along the zygomatic arch in the horizontal plane and is subsequently moved cranially; the temporalis muscle is visualized lying in the temporal fossa A 1]. Th. Th1]. TMyofascial trigger points inside the temporalis muscle can lead to tension headaches. In 2003, McGuigan et al.  reportedThe procerus muscle originates from the fascia over the lower portion of the nasal bone and is inserted into the skin overlying the lower forehead between the eyebrows. It is innervated by the temporal branch of the facial nerve and receives its blood supply from the facial artery. Contraction of the procerus muscle depresses the medial end of the eyebrow and wrinkles the glabellar skin .The transducer is placed in the horizontal plane on the lower portion of the forehead between the eyebrows and slightly cranial to the nasion  A. The shPatients with progressive supranuclear palsy may present focal dystonia of the procerus muscle (referred to as the procerus sign) along with reduced blinking, lid retraction, and gaze palsy . BotulinThe depressor supercilii muscle originates from the medial orbital rim and is inserted on the medial wall of the bony orbit. It is innervated by the facial nerve and receives its blood supply from the supratrochlear artery. Contraction of this muscle leads to downward movement of the eyebrow .The transducer is placed in the horizontal plane on the middle third of the eyebrow. The depressor supercilii is observed lateral to the procerus muscle beneath the SMAS A. SlightThe depressor supercilii was previously considered an extension/branch of the orbicularis oculi or corrugator supercilii muscle; however, it was subsequently confirmed to be a distinct muscle . The depThe corrugator supercilii originates from the supraorbital ridge and is inserted into the skin over the forehead, near the eyebrow. It is innervated by the facial nerve and receives its blood supply from the ophthalmic artery. Contraction of this muscle pulls the eyebrow downward and medially .The center of the transducer is placed on the middle third of the eyebrow in the horizontal plane. The corrugator supercilii is visualized deep to the depressor supercilii, with its lateral border beneath the orbicularis oculi A. The suThe corrugator supercilii is referred to as the “frowning muscle”; its contraction results in the formation of vertical wrinkles on the forehead. Botulinum toxin injections into the corrugator supercilii effectively flatten the glabellar region and normalize the contour of the medial eyebrow in patients with thyroid eye diseases .The orbicularis oculi muscle originates from the frontal bone, medial palpebral ligament, and lacrimal bone and is inserted on the lateral palpebral raphe. It is innervated by the temporal and zygomatic branches of the facial nerve and receives its blood supply from the ophthalmic, zygomatico-orbital, and angular arteries. Contraction of this muscles closes the eyelid .The transducer is placed over the eyebrow in the horizontal plane, and the muscle is visualized lateral to the corrugator supercilii A. The trThe orbicularis oculi plays an important role in the blink reflex, which is used to evaluate the integrity of the trigeminal and facial nerves. The muscle often serves as the target for upper eyelid blepharoplasty, which is used in the treatment of sunken eyes .The nasalis originates from the maxilla and is inserted into the nasal bone. It is innervated by the buccal branch of the facial nerve and receives its blood supply from the superior labial artery. Contraction of the muscle leads to compression of the nasal bridge and depression of the nasal tip .The transducer is placed in the oblique coronal plane along the nasal cartilage; the nasalis is visualized in its short axis above the cartilage. The transducer can be redirected to the oblique horizontal plane to observe the muscle along its long axis  25]..25].Contraction of the nasalis enlarges the nose and stretches the nostril. Overactivation of the muscle produces bunny lines ; botulinum toxin injections soften and erase these lines .The levator labii superioris alaeque nasi originates from the nasal bone and is inserted into the nostril and upper lip. It is innervated by the buccal branch of the facial nerve and receives its blood supply from the angular branch of the facial and infraorbital branches of the maxillary arteries. Contraction of the muscle elevates the upper lip to expose the upper teeth .The transducer is placed in an oblique horizontal plane that passes through the nasal crease. The muscle is observed lateral to the nasalis and medial to the levator labii superioris A. The trOveractivation of the levator labii superioris alaeque nasi results in a gummy smile, which is characterized by excessive gingival display on smiling. Botulinum toxin injection into this muscle can lengthen the upper lip to increase coverage of the gingiva and can also soften and minimize a prominent nasolabial fold .The levator labii superioris originates from the medial infraorbital region and is inserted into the skin and muscle over the upper lip. It is innervated by the buccal branch of the facial nerve and receives its blood supply from the facial artery. Contraction of this muscle elevates the upper lip .The transducer is placed in the middle of the inferior orbital rim in the horizontal plane, which initially facilitates visualization of the orbicularis oculi, followed by visualization of the levator labii superioris in its short axis, which lies above the infraorbital foramen A. FollowSimilar to the levator superioris alaeque nasi, the levator labii superioris is targeted to treat a gummy smile .The levator anguli oris originates from the maxilla and is inserted into the modiolus. It receives its blood supply from the facial artery and is innervated by the buccal branch of the facial nerve. Its contraction elevates the angle of the mouth .The scanning method is the same as that used for the levator labii superioris  which coThe levator anguli oris is used for reconstruction of nasal defects secondary to surgical removal of tumors in this area. The muscle can also be considered as a target for botulinum toxin injections to correct a gummy smile .The zygomaticus minor originates from the zygomatic bone and is inserted on the skin of the upper lip. It is innervated by the buccal branch of the facial nerve and receives its blood supply from the facial artery. Contraction of this muscle elevates the upper lip .The transducer is placed over the lateral inferior corner of the orbital rim in the horizontal plane. The origin of the zygomaticus minor can be visualized beneath the orbicularis oculi muscle A. The meThe levator labii superioris is partially covered by the levator labii superioris alaeque nasi and the zygomaticus minor. Botulinum toxin injections into the zygomaticus minor are usually considered to treat a gummy smile or facial asymmetry in patients with excessive upward and lateral displacement of the upper lip .The zygomaticus major originates from the lateral aspect of the zygomatic bone and is inserted into the modiolus  of the mouth. It is innervated by the buccal and zygomatic branches of the facial nerve and receives its blood supply from the superior labial branch of the facial artery. This muscle participates in elevation and contraction of the angle of the mouth .The transducer is placed over the inferior lateral edge of the orbital rim in the horizontal plane. The zygomaticus major is usually visualized lateral to the zygomaticus minor A; howeveInfiltration of the botulinum toxin into the zygomaticus major during injection of the adjacent muscles may cause partial lip ptosis. Botulinum toxin injections into the zygomaticus major can be considered for correction of facial asymmetry in patients in whom the angle of the mouth is excessively drawn backward/upward when smiling .The masseter muscle has two heads . The superficial head originates from the anterior two-thirds and the deep head from the posterior third of the zygomatic arch. The masseter muscle is inserted on the lateral surface of the mandibular ramus and angle. It is innervated by the masseteric branch of the mandibular nerve and receives its blood supply from the masseteric artery. Contraction of the masseter causes mandibular elevation and protrusion .The transducer is placed along the zygomatic arch in the horizontal plane and is subsequently moved caudally to visualize the masseter muscle in its short axis A. The trMasseter hypertrophy can occur secondary to bruxism or habitual tooth grinding, which may lead to a square face (widening of the lower third of the face). Botulinum toxin injections into the mandibular insertion of the masseter muscle are useful to manage teeth grinding and jaw contouring, although caution is warranted to avoid injury to the parotid gland .The orbicularis oris originates from the medial aspect of the maxilla and mandible, the perioral skin/muscles, as well as the modiolus, and is inserted into the skin and mucosa of the lip. It is innervated by the buccal branch of the facial nerve and receives its blood supply from the facial, maxillary, and superficial temporal arteries. Contraction of this muscle leads to compression of the mouth and protrusion of the lip .The transducer is placed over the lower philtrum  and labiomandibular crease in the horizontal plane. The orbicularis oris appears as a thin hypoechoic band between the two layers of connective tissue A 36]. T. T36]. TBotulinum toxin injections into the orbicularis oris can be considered to decrease perioral vertical rhytids. A small volume of the toxin should be injected into the superficial portion of the muscle to avoid impairment of phonation and sucking functions .The buccinator muscle originates from the alveolar process of the maxilla, the buccinator ridge of the mandible, and the pterygomandibular raphe. It is inserted onto the modiolus, and its fibers blend with those of the orbicularis oris. It is innervated by the buccal branch of the facial nerve and receives its blood supply from the buccal artery. Its contraction compresses the cheek against the molar teeth, which facilitates whistling .The transducer is placed in the horizontal plane between the zygomatic arch and the mandible to initially visualize the masseter in its short axis . The traFacial synkinesis, defined as inappropriate and inadvertent movements of the facial muscles during certain voluntary facial expressions, is a common sequela of facial nerve palsy. The buccinator muscle is commonly involved in facial synkinesis, which can be treated by botulinum toxin injections .The risorius muscle originates from the parotid fascia and buccal skin and is inserted on the modiolus. It is innervated by the buccal branch of the facial nerve and receives its blood supply from the superior labial branch of the facial artery. Its contraction extends the angle of the mouth laterally .The transducer is initially placed in the horizontal plane to visualize the masseter muscle in its short axis . The traAccidental infiltration of botulinum toxin into the risorius may occur during injection into the masseter muscle. Caution is warranted to avoid facial asymmetry.The mentalis muscle originates from the anterior mandible and is inserted into the chin. It is innervated by the mandibular branch of the facial nerve and receives its blood supply from the inferior labial branch of the facial artery and the mental branch of the maxillary artery. Contraction of the mentalis elevates the chin and results in lower lip protrusion .The transducer is placed over the midline of the chin in the horizontal plane. The mentalis muscle is identified in its short axis above the mandible A. The trHereditary geniospasm, a rare movement disorder, is characterized by episodic involuntary movements of the mentalis muscle . MentaliThe depressor labii inferioris originates from the oblique line of the mandible and is inserted into the integument of the lower lip . It is iThe transducer is initially placed over the midline of the chin to visualize the mentalis muscle and is subsequently relocated more laterally to identify the depressor labii inferioris above the lateral edge of the mentalis A 3]. Th. Th3]. TOveractivation of the depressor labii inferioris may cause a droopy appearance of the face secondary to lowering of the lower lip; intramuscular botulinum toxin injections are useful in such cases .The depressor anguli oris originates from the oblique line of the mandible and is inserted into the modiolus . It is iThe transducer is placed over the midline of the chin and is subsequently moved laterally. The mentalis muscle is visualized, followed by the depressor labii inferioris and depressor anguli oris A. The trOveractivity of the depressor anguli oris lowers the mouth commissure, which leads to the expression of sadness or frustration. Botulinum toxin injections elevate the angle of the mouth and improve an individual’s smile .Although the present article is a pictorial essay and narrative review, we performed a systematic literature search of the PubMed, Medline, and Web of Science databases (without language limitations) from inception to January 2022 to identify articles relevant to US imaging of facial muscles. The following keywords and their combinations were used: ultrasound, sonography, ultrasonography and face, facial muscles. The following search strategy had been used for literature search: (“ultrasound” or “ultrasonography” or “sonography”) AND . The inclusion criteria were cross-sectional, case-control, cohort and randomized controlled studies that use ultrasound imaging to visualize the group of facial muscles. The exclusion criteria comprised (1) nonhuman studies, (2) case report or series, (3) review articles and (4) studies that only investigate a single muscle. Our review only included articles that described more than one facial muscle.The process of the literature search was detailed in the In 2014, Volk et al.  used US In 2016, Volk et al.  investigIn 2019, Abe et al.  investigIn 2021, Hormazabal-Peralta et al.  investigWe had several viewpoints regarding sonoanatomy described in the seven included articles. First, the scanning techniques for the large-sized facial muscles  and adjacent bony landmarks were consistent across the enrolled studies. There were some variations in the imaging methods for small-sized muscles such as the levator labii superioris and zygomaticus minor. Second, most of the enrolled studies used the short-axis views to examine the facial muscles, whereas their longitudinal fiber arrangement could not be clearly depicted. In our protocol, we employed the short- and long-axis views to visualize the target muscles, which could compensate the weakness of the methods reported in the previous studies. Third, during the literature search, we did not identify studies comparing US imaging with other imaging tools (like magnetic resonance imaging). A prospective trial would be needed to investigate the validity of US imaging for assessing the texture of the facial muscles in comparison with other imaging tools.Based on a review of the included articles, we observed that US may serve as a useful tool to quantify facial muscle thickness, as well as to evaluate muscle echotexture. Variations in the reliability of measurements across different muscles may be attributable to changes in scanning methods, which highlights the importance of a standardized and stepwise evaluation protocol (as described in this article). Although the botulinum toxin is widely used for rejuvenation and in cosmetic dermatology, few studies have investigated the role of US guidance in comparison with landmark-based injections. The facial muscles are thin and superficially located; therefore, in our opinion, the use of high-frequency (hockey-stick) transducers and an out-of-plane injection technique may be useful. Future studies are warranted to conclusively establish the clinical effectiveness and safety of such interventions.Several limitations of using US guidance for injecting facial muscles should be acknowledged. First, utilization of US guidance for most facial muscles may be excessive because the majority of facial muscles can be identified with anatomical surface landmarks, such as most movement disorders  . Second,High-resolution US enables the delineation of facial muscles, and any asymmetry and targets for possible interventions can be promptly evaluated. Botulinum toxin injections are usually performed based on surface anatomy, and currently, US guidance is rarely used for this purpose. Further prospective studies are warranted to establish the feasibility and advantages of US imaging and guidance in the management of facial (muscle) disorders. Clinicians should consider the complementary role of US and electrodiagnostic tests in these patients. Notably, US guidance can facilitate accurate needle insertion during electromyography of the aforementioned thin/small muscles.