Follow-up of environmental impacts is an integral part of the Environmental Impact Assessment (EIA) process, closely related to the effectiveness of the instrument. EIA follow-up has been receiving a lot of interest f...Follow-up of environmental impacts is an integral part of the Environmental Impact Assessment (EIA) process, closely related to the effectiveness of the instrument. EIA follow-up has been receiving a lot of interest from scientists and practitioners, though it is recognized as one of the weakest points of EIA systems globally. Also, EIA follow-up is influenced by the context, mainly in terms of the types of projects or activities and their related impacts on the environment. Therefore, the present paper is focused on the investigation of the follow-up stage applied to the activity of seismic survey coupled with offshore oil & gas exploitation in Brazil. Research was based on a qualitative approach that included document analysis and semi-structured interviews with analysts involved in EIA processes, and sought to generate evidence of effectiveness of the EIA follow-up as conducted by the Federal Environment Agency (Ibama) in order to situate the practice of follow-up in the broader context of international best practice principles. Based on the findings, it was concluded that, due to the peculiarities of offshore seismic survey, it is necessary to promote adaptations in the procedures for monitoring impacts in order to ensure proper alignment with the principles and conceptual foundations that guide EIA practice. Specifically, the timing of the execution of the activity imposes challenges for its integration into the “conventional” cycle that has guided the monitoring of the impacts in the EIA of projects.展开更多
This article investigates a multi-circular path-following formation control with reinforced transient profiles for nonholonomic vehicles connected by a digraph.A multi-circular formation controller endowed with the fe...This article investigates a multi-circular path-following formation control with reinforced transient profiles for nonholonomic vehicles connected by a digraph.A multi-circular formation controller endowed with the feature of spatial-temporal decoupling is devised for a group of vehicles guided by a virtual leader evolving along an implicit path,which allows for a circumnavigation on multiple circles with an anticipant angular spacing.In addition,notice that it typically imposes a stringent time constraint on time-sensitive enclosing scenarios,hence an improved prescribed performance control(IPPC)using novel tighter behavior boundaries is presented to enhance transient capabilities with an ensured appointed-time convergence free from any overshoots.The significant merits are that coordinated circumnavigation along different circles can be realized via executing geometric and dynamic assignments independently with modified transient profiles.Furthermore,all variables existing in the entire system are analyzed to be convergent.Simulation and experimental results are provided to validate the utility of suggested solution.展开更多
This paper presents a finite-time sideslip differentiator-based line-of-sight(LOS)guidance method for robust path following of snake robots.Firstly,finite-time stable sideslip differentiator and adaptive LOS guidance ...This paper presents a finite-time sideslip differentiator-based line-of-sight(LOS)guidance method for robust path following of snake robots.Firstly,finite-time stable sideslip differentiator and adaptive LOS guidance method are proposed to counteract sideslip drift caused by cross-track velocity.The proposed differentiator can accurately observe the cross-track error and sideslip angle for snake robots to avoid errors caused by calculating sideslip angle approximately.In our method,the designed piecewise auxiliary function guarantees the finite-time stability of position errors.Secondly,for the case of external disturbances and state constraints,a Barrier Lyapunov functionbased backstepping adaptive path following controller is presented to improve the robot’s robustness.The uniform ultimate boundedness of the closed-loop system is proved by analyzing stability.Additionally,a gait frequency adjustment-based virtual velocity control input is derived to achieve the exponential convergence of the tangential velocity.At last,the availability and superiority of this work are shown through simulation and experiment results.展开更多
Objective:To access the level of knowledge,perceptions,and practice towards adverse events following immunization(AEFI)surveillance among vaccination workers in Zhejiang province,China.Methods:This was a cross-section...Objective:To access the level of knowledge,perceptions,and practice towards adverse events following immunization(AEFI)surveillance among vaccination workers in Zhejiang province,China.Methods:This was a cross-sectional survey involving 768 vaccination workers.Data were collected using self-administered questionnaires and analyzed by using SAS 9.3 software.Knowledge,perceptions,and practice on AEFI surveillance were summarized using frequency tables.The mean±SD value was used as the cut-off for defining good(values≥mean)and poor(values<mean)knowledge,perceptions or practice.Binary logistic regression analysis was used to determine sociodemographic variables associated with knowledge,perceptions,and practice towards AEFI.Results:The proportions of good knowledge,perceptions and practice on AEFI surveillance were 78.13%,57.81%and 66.15%,respectively.Having a higher education background,longer years of experience,previous training on AEFI and≥30 years of age were factors associated with good knowledge,perceptions and practice on AEFI surveillance among vaccination workers.Conclusions:Over half of the respondents had good knowledge,perceptions and practice on AEFI surveillance work.Interventions on improving the vaccination workers’knowledge,perceptions and practice on AEFI surveillance should be considered in order to develop a more effective surveillance system.展开更多
The single-file movement experiment offered a convenient way to investigate the one-dimensional leader–follower behavior of pedestrians. This study investigated the time delays of children pedestrians in the leader–...The single-file movement experiment offered a convenient way to investigate the one-dimensional leader–follower behavior of pedestrians. This study investigated the time delays of children pedestrians in the leader–follower behavior by introducing a time-dependent delayed speed correlation. A total of 118 German students from the fifth grade(aged11–12 years old) and the 11th grade(aged 17–18 years old) participated the single-file experiment. The characteristic delay time for each pedestrian was identified by optimising the time-dependent delayed speed correlation. The influences of the curvature of the experimental scenario, density, age, and gender on the delay time were statistically examined. The results suggested that to a large extent, the revealed characteristic delay time was a density-dependent variable, and none of the curvatures, the age and gender of the individual, and the age and gender of the leader had a significant influence on it. The findings from this study are variable resources to understand the leader–follower behavior among children pedestrians and to build related simulation models.展开更多
This paper studies the moving path following(MPF)problem for fixed-wing unmanned aerial vehicle(UAV)under output constraints and wind disturbances.The vehicle is required to converge to a reference path moving with re...This paper studies the moving path following(MPF)problem for fixed-wing unmanned aerial vehicle(UAV)under output constraints and wind disturbances.The vehicle is required to converge to a reference path moving with respect to the inertial frame,while the path following error is not expected to violate the predefined boundaries.Differently from existing moving path following guidance laws,the proposed method removes complex geometric transformation by formulating the moving path following problem into a second-order time-varying control problem.A nominal moving path following guidance law is designed with disturbances and their derivatives estimated by high-order disturbance observers.To guarantee that the path following error will not exceed the prescribed bounds,a robust control barrier function is developed and incorporated into controller design with quadratic program based framework.The proposed method does not require the initial position of the UAV to be within predefined boundaries.And the safety margin concept makes error-constraint be respected even if in a noisy environment.The proposed guidance law is validated through numerical simulations of shipboard landing and hardware-in-theloop(HIL)experiments.展开更多
This study is designed to solve supply chain inefficiencies caused by some members’financial problems,such as capital shortages and financing restrictions in a stochastic environment.To this end,we have established a...This study is designed to solve supply chain inefficiencies caused by some members’financial problems,such as capital shortages and financing restrictions in a stochastic environment.To this end,we have established a supply chain finance framework by designing two novel coordinating contracts based on trade credit financing for different problem settings.These contracts are modeled in the form of multi-leader Stackelberg games that address horizontal and vertical competition in a supply chain consisting of multiple suppliers and a financially constrained manufacturer.However,previous studies in the trade credit literature have addressed only simple vertical competition,that is,seller-buyer competition.To solve the proposed models,two algorithms were developed by combining population-based metaheuristics,the Nash-domination concept,and the Nikaido-Isoda function.The results demonstrate that the proposed supply chain finance framework can eliminate supply chain inefficiencies and make a large profit for suppliers,as well as the financially constrained manufacturer.Furthermore,the results of the contracts’analysis showed that if the manufacturer is required to settle its payments to suppliers before the end of the period,the trade credit contract cannot coordinate the supply chain because of a lack of incentive for suppliers.However,if the manufacturer is allowed to extend its payments to the end of the period,the proposed trade credit financing contract can coordinate the supply chain.Finally,the sensitivity analysis results indicate that the worse the financial status of the manufacturer,the more bargaining power suppliers have in determining the contract parameters for more profit.展开更多
To solve the path following control problem for unmanned surface vehicles(USVs),a control method based on deep reinforcement learning(DRL)with long short-term memory(LSTM)networks is proposed.A distributed proximal po...To solve the path following control problem for unmanned surface vehicles(USVs),a control method based on deep reinforcement learning(DRL)with long short-term memory(LSTM)networks is proposed.A distributed proximal policy opti-mization(DPPO)algorithm,which is a modified actor-critic-based type of reinforcement learning algorithm,is adapted to improve the controller performance in repeated trials.The LSTM network structure is introduced to solve the strong temporal cor-relation USV control problem.In addition,a specially designed path dataset,including straight and curved paths,is established to simulate various sailing scenarios so that the reinforcement learning controller can obtain as much handling experience as possible.Extensive numerical simulation results demonstrate that the proposed method has better control performance under missions involving complex maneuvers than trained with limited scenarios and can potentially be applied in practice.展开更多
Deeply-rooted in China’s popular culture,precious scrolls(Baojuan)are the golden material to display popular religious belief of the mass.Based on the rare texts sorted and annotated by Shang Lixin,Dutch Sinologist W...Deeply-rooted in China’s popular culture,precious scrolls(Baojuan)are the golden material to display popular religious belief of the mass.Based on the rare texts sorted and annotated by Shang Lixin,Dutch Sinologist Wilt L.Idema continues his journey of translating precious scrolls.Focused on the theme of devoted women Buddhist followers in Ming dynasty,he explores the ethical choices of married women in facing the betrayal of servants or concubines.His translations not only add important reading material to Western readers in the field of Chinese popular literature,but also set standard for the coming translators in rendering Chinese ballads.展开更多
Background: Pregnant women bear the greatest burden of people living with HIV in the West Africa sub-region, and the country requires continuous optimal follow-up care for their disease after delivery. Documentation o...Background: Pregnant women bear the greatest burden of people living with HIV in the West Africa sub-region, and the country requires continuous optimal follow-up care for their disease after delivery. Documentation of such very important services is rarely done in this high-burden environment, and hence the present study. Method: A 15-year retrospective review of medical records of HIV-positive pregnant women who attended antenatal care services from January 2006 to December 2020 at the prevention of the mothers-to-child transmission unit of the health facility was carried out to document the HIV service provided at the unit, and the follow-up care at the adult HIV special treatment clinic for the continuation of their HIV treatment. Results: Of the 1245 HIV-positive pregnant mothers reviewed during the period, 702 (56.4%) were between the ages of 26 - 35 years, 1043 (83.8%) were on HIV treatment before their index pregnancy, 202 (16.2%) were diagnosed of HIV infection during their last trimester and labor, while 878 (70.5%) continued their HIV services at adult HIV special treatment clinic after delivery. The predictors of continuous care include: maternal parity with [OR] 0.51 (0.35 - 0.73), p = 0.02, time of presentation in trimester with [OR] 1.54 (1.15 - 2.06), p = 0.003, duration on antiretroviral therapy [OR] 2.14 (1.57 - 2.9) p Conclusion: The high rate of optimal follow-up care of HIV-positive mothers after delivery in the adult special treatment clinic in this study speaks of the preparedness and good supportive services provided to these mothers in the health facility. However, the high rate of loss to follow-up among this cohort of women requires a more focused intervention during their postpartum period for a better outcome.展开更多
Objectives: To assess the factors influencing the ophthalmological follow-up of sickle cell patients in Togo. Materials and Methods: The national center of research and care for sickle cell patients (CNRSD) served as ...Objectives: To assess the factors influencing the ophthalmological follow-up of sickle cell patients in Togo. Materials and Methods: The national center of research and care for sickle cell patients (CNRSD) served as study setting. It was a descriptive and analytical study by interview over a three-month period from December 01, 2020 to March 02, 2021. Was included in the study, any patient with sickle cell disease genotype SS or SC, age ≥ 17 years, regularly followed at the CNRSD and having accepted the interview by a survey sheet. Excluded were patients with sickle cell trait genotype AS or AC or with a disability that prevented them from being interviewed. Results: Two hundred and fifty (250) patients with sickle cell disease were interviewed. The mean age was 29.1 years ± 11.12 years [17 years;67 years] and the sex ratio = 0.52. Nine patients over ten (9/10) attended at least secondary school. The jobless represented 25.60% of the total population followed respectively by students and laborers in 20.40% and 16% of cases. Twenty-four percent (24%) of patients were followed up in ophthalmology department. Statistically, there was no significant relationship between level of education (p = 0.4083), occupation (p = 0.6441) and knowledge of the ocular complications of sickle cell disease. Statistically, there was a significant relationship between knowledge of the ocular complications of sickle cell disease and compliance with ophthalmological follow-up (p = 0.0009). Conclusion: The knowledge of eye disorders related to sickle cell disease by patients with sickle cell disease improves their ophthalmological follow-up. Greater awareness on eye disorders related to sickle cell disease by medical staff towards patients with sickle cell disease would improve ophthalmological follow-up. .展开更多
Hepatitis B virus (HBV) infection is a major public health problem worldwide. The aim of this study was to document the dynamics of HBV viral load during the follow-up of chronic hepatitis B patients at the Saint Cami...Hepatitis B virus (HBV) infection is a major public health problem worldwide. The aim of this study was to document the dynamics of HBV viral load during the follow-up of chronic hepatitis B patients at the Saint Camille Hospital in Ouagadougou (HOSCO) from 2017 to 2021. This descriptive retrospective study was carried out in the Hepato-Gastro-Enterology Department of HOSCO and focused on patients who were undergoing treatment for chronic viral hepatitis B. A total of 260 cases of chronic hepatitis B were included in the study. The most affected age group was 21 to 30 years, accounting for 48.08% of the cases. Lifestyle factors included alcohol consumption (3.08%) and tobacco use (2.69%). Major risk factors for transmission included lack of vaccination (98.46%), family history of HBV infection (68.00%) and engagement in high-risk activities (28.00%). Patients requiring treatment were prescribed Tenofovir 300 mg tablets. FibroScan<sup>®</sup> showed the presence of stage F3-F4 fibrosis (2.14%) and S3 steatosis (13.33%). After one year of follow-up, 6.92% of patients achieved an undetectable viral load with normalized transaminase levels. The majority of other patients had a detectable viral load but below 20,000 IU/mL. The prevalence of viral hepatitis B remains significant worldwide. Although effective and well-monitored treatment can lead to undetectable viremia, prevention remains the most effective strategy for successful management of this disease.展开更多
Objective: The aim of this study was to describe the use of the postpartum intrauterine device in the maternity ward of the Ratoma communal medical center in Conakry. Methods: This was a descriptive cross-sectional st...Objective: The aim of this study was to describe the use of the postpartum intrauterine device in the maternity ward of the Ratoma communal medical center in Conakry. Methods: This was a descriptive cross-sectional study carried out between July 1<sup>st</sup> 2015 and June 30 2016, i.e. a duration of one year. Results: A total of 551 patients received advice on various contraceptive methods. Most of this advice was given in the post-partum period (40.2%) and during antenatal care (39.1%). Of the patients advised, 87 (15.8%) used the intrauterine device. The majority of users (93%) were married and uneducated (63.2%), and 39.1% were poor. The majority (56.3%) of intra-uterine devices were inserted in the immediate post-partum period. The majority of women had no adverse events either during the first six weeks (n = 57;65.5%) or at 3<sup>rd</sup> months (n = 75;86.2%) or 6<sup>th</sup> months (n = 76;87.4%) after IUD insertion. Most users remained complication-free throughout the follow-up period (n = 76;87.4% at 6<sup>th</sup> weeks and 3<sup>rd</sup> months, and n = 77;88.5% at 6<sup>th</sup> months). The continuation rate was 89.7% at 6 weeks and 3<sup>rd</sup> months, and 87.4% at 6<sup>th</sup> months after insertion. The majority of users (87.0%) were satisfied with the care they received. Conclusion: This study showed very few complications among intrauterine device users, and high continuation and satisfaction rates. The intrauterine device is a long-acting, effective, reversible and safe contraceptive that can be used by most women for birth spacing in Guinea, where women do not regularly visit health facilities.展开更多
Congenital pure kyphosis due to failure of vertebral body segmentation is a relatively rare entity, and surgical intervention is infrequent compared to that for failure of vertebral body formation [1] [2]. There are v...Congenital pure kyphosis due to failure of vertebral body segmentation is a relatively rare entity, and surgical intervention is infrequent compared to that for failure of vertebral body formation [1] [2]. There are very few reports of long-term follow-up of surgical treatment in patients with congenital pure kyphosis, and all the reported cases were diagnosed as failure of formation and had an age at the time of surgery of less than 18 years. It is important for orthopedic surgeons to follow the postoperative course of rare cases over 30 years. Here, we present a surgically treated case with ultra-long term follow-up of a 50-year-old patient with congenital pure kyphosis of the lumbar spine. Imaging of the lumbar spine showed six vertebrae and an unsegmented bar at L3-4 causing a pure kyphosis of 54°. The wedge-shaped block vertebra had 4 pedicles with the neural foramen between the pedicles without concomitant disc space, with compensatory thoracic hypokyphosis and lower lumbar hyperlordosis. One-stage correction and fusion surgery using anterior opening and posterior closing osteotomy was successfully performed. Both clinical and radiographic results were excellent and have been maintained for over 30 years postoperatively. The basic principle in the surgical treatment of adult spinal deformity is to achieve and maintain a good global sagittal balance over time. This case reaffirms the importance of spinopelvic harmony.展开更多
Background and objectives: Breast Imaging Reporting and Data System in Category 3 (BIRADS-3) includes probably benign lesions which need a short-term imaging follow-up. However, in our context, the lesions graded BIRA...Background and objectives: Breast Imaging Reporting and Data System in Category 3 (BIRADS-3) includes probably benign lesions which need a short-term imaging follow-up. However, in our context, the lesions graded BIRADS-3 remain insufficiently evaluated. We therefore conducted this study to assess the cancer occurrence and associated factors in BIRADS-3 lesions during the follow-up in order to propose an adaptation of the management for lesions in this category in our setting. Patients and methods: A retrospective longitudinal study of patients with lesions initially classified as BIRADS-3 and who realised each at least one additional imaging check-up between January 2014 and December 2022 in five Yaoundé hospitals. All clinical and imaging data were analysed using SPSS<sup>®</sup> 21.0 software with a significant p-value Results: Patients were aged 13 to 73 (33.0 ± 13.4) years, with a history of breast mass (315 cases;79.7%), breast pain (25 patients;6.3%), nipple discharge (20 patients;5.1%) or past family history of breast cancer (25 cases;6.3%). The most common baseline abnormalities were mammogram opacities (64.8%) and microcalcifications (48.6%), whereas initial breast ultrasound showed solid masses (77.0%) and cystic lesions (11.1%). Compliance with imaging appointment periods was low with only 23.9% of all patients performing an imaging control at the scheduled moment. During the follow-up, 115 patients (29.1%) were upgraded to BIRADS-4 and histology performed revealed 43 cancers (10.9% of overall initial BIRADS-3 sample). The presence of malignancies was associated to age above 40 years (p = 0.0001) and to the presence of nipple discharge (p = 0.0375). Conclusion: The frequency of malignancies among initial BIRADS-3 lesions in our series is higher than that described in the guidelines. This study highlights the need to be more proactive in the management of BIRADS-3 lesions in our setting as the compliance with follow-up is low. So, biopsy should be considered as an alternative to long-term follow-up for patients above 40, non-compliant with imaging check-ups and presenting with nipple discharge.展开更多
文摘Follow-up of environmental impacts is an integral part of the Environmental Impact Assessment (EIA) process, closely related to the effectiveness of the instrument. EIA follow-up has been receiving a lot of interest from scientists and practitioners, though it is recognized as one of the weakest points of EIA systems globally. Also, EIA follow-up is influenced by the context, mainly in terms of the types of projects or activities and their related impacts on the environment. Therefore, the present paper is focused on the investigation of the follow-up stage applied to the activity of seismic survey coupled with offshore oil & gas exploitation in Brazil. Research was based on a qualitative approach that included document analysis and semi-structured interviews with analysts involved in EIA processes, and sought to generate evidence of effectiveness of the EIA follow-up as conducted by the Federal Environment Agency (Ibama) in order to situate the practice of follow-up in the broader context of international best practice principles. Based on the findings, it was concluded that, due to the peculiarities of offshore seismic survey, it is necessary to promote adaptations in the procedures for monitoring impacts in order to ensure proper alignment with the principles and conceptual foundations that guide EIA practice. Specifically, the timing of the execution of the activity imposes challenges for its integration into the “conventional” cycle that has guided the monitoring of the impacts in the EIA of projects.
基金supported in part by the National Natural Science Foundation of China under Grant Nos.62173312 and 61803348in part by the National Major Scientific Instruments Development Project under Grant No.61927807+3 种基金in part by the Program for the Innovative Talents of Higher Education Institutions of ShanxiShanxi Province Science Foundation for Excellent Youthsin part by the Shanxi"1331 Project"Key Subjects Construction(1331KSC)in part by Graduate Innovation Project of Shanxi Province under Grant No.2021Y617。
文摘This article investigates a multi-circular path-following formation control with reinforced transient profiles for nonholonomic vehicles connected by a digraph.A multi-circular formation controller endowed with the feature of spatial-temporal decoupling is devised for a group of vehicles guided by a virtual leader evolving along an implicit path,which allows for a circumnavigation on multiple circles with an anticipant angular spacing.In addition,notice that it typically imposes a stringent time constraint on time-sensitive enclosing scenarios,hence an improved prescribed performance control(IPPC)using novel tighter behavior boundaries is presented to enhance transient capabilities with an ensured appointed-time convergence free from any overshoots.The significant merits are that coordinated circumnavigation along different circles can be realized via executing geometric and dynamic assignments independently with modified transient profiles.Furthermore,all variables existing in the entire system are analyzed to be convergent.Simulation and experimental results are provided to validate the utility of suggested solution.
基金supported in part by the National Natural Science Foundation of China(61825305,62171274,U1933125,U2241228,62273019)the Shanghai Science and Technology Major Project(2021SHZDZX)+2 种基金the National Natural Science Foundation of China through the Main Research Projecton Machine Behavior and Human-Machine Collaborated Decision Making Methodology(72192820)the Third Research Projecton Human Behavior in HumanMachine Collaboration(72192822)the China Postdoctoral Science Foundation(2022M710093)。
文摘This paper presents a finite-time sideslip differentiator-based line-of-sight(LOS)guidance method for robust path following of snake robots.Firstly,finite-time stable sideslip differentiator and adaptive LOS guidance method are proposed to counteract sideslip drift caused by cross-track velocity.The proposed differentiator can accurately observe the cross-track error and sideslip angle for snake robots to avoid errors caused by calculating sideslip angle approximately.In our method,the designed piecewise auxiliary function guarantees the finite-time stability of position errors.Secondly,for the case of external disturbances and state constraints,a Barrier Lyapunov functionbased backstepping adaptive path following controller is presented to improve the robot’s robustness.The uniform ultimate boundedness of the closed-loop system is proved by analyzing stability.Additionally,a gait frequency adjustment-based virtual velocity control input is derived to achieve the exponential convergence of the tangential velocity.At last,the availability and superiority of this work are shown through simulation and experiment results.
基金funded by medical and health science and technology project of Zhejiang province (Grant number:2023KY633)
文摘Objective:To access the level of knowledge,perceptions,and practice towards adverse events following immunization(AEFI)surveillance among vaccination workers in Zhejiang province,China.Methods:This was a cross-sectional survey involving 768 vaccination workers.Data were collected using self-administered questionnaires and analyzed by using SAS 9.3 software.Knowledge,perceptions,and practice on AEFI surveillance were summarized using frequency tables.The mean±SD value was used as the cut-off for defining good(values≥mean)and poor(values<mean)knowledge,perceptions or practice.Binary logistic regression analysis was used to determine sociodemographic variables associated with knowledge,perceptions,and practice towards AEFI.Results:The proportions of good knowledge,perceptions and practice on AEFI surveillance were 78.13%,57.81%and 66.15%,respectively.Having a higher education background,longer years of experience,previous training on AEFI and≥30 years of age were factors associated with good knowledge,perceptions and practice on AEFI surveillance among vaccination workers.Conclusions:Over half of the respondents had good knowledge,perceptions and practice on AEFI surveillance work.Interventions on improving the vaccination workers’knowledge,perceptions and practice on AEFI surveillance should be considered in order to develop a more effective surveillance system.
基金supported by the National Natural Science Foundation of China (Grant Nos. 71901175, 71901060, and 72101276)。
文摘The single-file movement experiment offered a convenient way to investigate the one-dimensional leader–follower behavior of pedestrians. This study investigated the time delays of children pedestrians in the leader–follower behavior by introducing a time-dependent delayed speed correlation. A total of 118 German students from the fifth grade(aged11–12 years old) and the 11th grade(aged 17–18 years old) participated the single-file experiment. The characteristic delay time for each pedestrian was identified by optimising the time-dependent delayed speed correlation. The influences of the curvature of the experimental scenario, density, age, and gender on the delay time were statistically examined. The results suggested that to a large extent, the revealed characteristic delay time was a density-dependent variable, and none of the curvatures, the age and gender of the individual, and the age and gender of the leader had a significant influence on it. The findings from this study are variable resources to understand the leader–follower behavior among children pedestrians and to build related simulation models.
基金supported in part by the National Natural Science Foundations of China(62173016,62073019)the Fundamental Research Funds for the Central Universities(YWF-23-JC-04,YWF-23-JC-02)。
文摘This paper studies the moving path following(MPF)problem for fixed-wing unmanned aerial vehicle(UAV)under output constraints and wind disturbances.The vehicle is required to converge to a reference path moving with respect to the inertial frame,while the path following error is not expected to violate the predefined boundaries.Differently from existing moving path following guidance laws,the proposed method removes complex geometric transformation by formulating the moving path following problem into a second-order time-varying control problem.A nominal moving path following guidance law is designed with disturbances and their derivatives estimated by high-order disturbance observers.To guarantee that the path following error will not exceed the prescribed bounds,a robust control barrier function is developed and incorporated into controller design with quadratic program based framework.The proposed method does not require the initial position of the UAV to be within predefined boundaries.And the safety margin concept makes error-constraint be respected even if in a noisy environment.The proposed guidance law is validated through numerical simulations of shipboard landing and hardware-in-theloop(HIL)experiments.
文摘This study is designed to solve supply chain inefficiencies caused by some members’financial problems,such as capital shortages and financing restrictions in a stochastic environment.To this end,we have established a supply chain finance framework by designing two novel coordinating contracts based on trade credit financing for different problem settings.These contracts are modeled in the form of multi-leader Stackelberg games that address horizontal and vertical competition in a supply chain consisting of multiple suppliers and a financially constrained manufacturer.However,previous studies in the trade credit literature have addressed only simple vertical competition,that is,seller-buyer competition.To solve the proposed models,two algorithms were developed by combining population-based metaheuristics,the Nash-domination concept,and the Nikaido-Isoda function.The results demonstrate that the proposed supply chain finance framework can eliminate supply chain inefficiencies and make a large profit for suppliers,as well as the financially constrained manufacturer.Furthermore,the results of the contracts’analysis showed that if the manufacturer is required to settle its payments to suppliers before the end of the period,the trade credit contract cannot coordinate the supply chain because of a lack of incentive for suppliers.However,if the manufacturer is allowed to extend its payments to the end of the period,the proposed trade credit financing contract can coordinate the supply chain.Finally,the sensitivity analysis results indicate that the worse the financial status of the manufacturer,the more bargaining power suppliers have in determining the contract parameters for more profit.
基金supported by the National Natural Science Foundation(61601491)the Natural Science Foundation of Hubei Province(2018CFC865)the China Postdoctoral Science Foundation Funded Project(2016T45686).
文摘To solve the path following control problem for unmanned surface vehicles(USVs),a control method based on deep reinforcement learning(DRL)with long short-term memory(LSTM)networks is proposed.A distributed proximal policy opti-mization(DPPO)algorithm,which is a modified actor-critic-based type of reinforcement learning algorithm,is adapted to improve the controller performance in repeated trials.The LSTM network structure is introduced to solve the strong temporal cor-relation USV control problem.In addition,a specially designed path dataset,including straight and curved paths,is established to simulate various sailing scenarios so that the reinforcement learning controller can obtain as much handling experience as possible.Extensive numerical simulation results demonstrate that the proposed method has better control performance under missions involving complex maneuvers than trained with limited scenarios and can potentially be applied in practice.
基金Under a doctoral project endowed by Gansu Provincial Department of Education,China,in 2022(2022QB-164)an innovation project endowed by Gansu Provincial Department of Education,China,in 2023(2023B-208)+1 种基金a humanities and social sciences project endowed by Gansu Federation of Social Science,China,in 2022(22ZC53)a doctoral project endowed by Longdong University,China,in 2022(XYBYSK2201).
文摘Deeply-rooted in China’s popular culture,precious scrolls(Baojuan)are the golden material to display popular religious belief of the mass.Based on the rare texts sorted and annotated by Shang Lixin,Dutch Sinologist Wilt L.Idema continues his journey of translating precious scrolls.Focused on the theme of devoted women Buddhist followers in Ming dynasty,he explores the ethical choices of married women in facing the betrayal of servants or concubines.His translations not only add important reading material to Western readers in the field of Chinese popular literature,but also set standard for the coming translators in rendering Chinese ballads.
文摘Background: Pregnant women bear the greatest burden of people living with HIV in the West Africa sub-region, and the country requires continuous optimal follow-up care for their disease after delivery. Documentation of such very important services is rarely done in this high-burden environment, and hence the present study. Method: A 15-year retrospective review of medical records of HIV-positive pregnant women who attended antenatal care services from January 2006 to December 2020 at the prevention of the mothers-to-child transmission unit of the health facility was carried out to document the HIV service provided at the unit, and the follow-up care at the adult HIV special treatment clinic for the continuation of their HIV treatment. Results: Of the 1245 HIV-positive pregnant mothers reviewed during the period, 702 (56.4%) were between the ages of 26 - 35 years, 1043 (83.8%) were on HIV treatment before their index pregnancy, 202 (16.2%) were diagnosed of HIV infection during their last trimester and labor, while 878 (70.5%) continued their HIV services at adult HIV special treatment clinic after delivery. The predictors of continuous care include: maternal parity with [OR] 0.51 (0.35 - 0.73), p = 0.02, time of presentation in trimester with [OR] 1.54 (1.15 - 2.06), p = 0.003, duration on antiretroviral therapy [OR] 2.14 (1.57 - 2.9) p Conclusion: The high rate of optimal follow-up care of HIV-positive mothers after delivery in the adult special treatment clinic in this study speaks of the preparedness and good supportive services provided to these mothers in the health facility. However, the high rate of loss to follow-up among this cohort of women requires a more focused intervention during their postpartum period for a better outcome.
文摘Objectives: To assess the factors influencing the ophthalmological follow-up of sickle cell patients in Togo. Materials and Methods: The national center of research and care for sickle cell patients (CNRSD) served as study setting. It was a descriptive and analytical study by interview over a three-month period from December 01, 2020 to March 02, 2021. Was included in the study, any patient with sickle cell disease genotype SS or SC, age ≥ 17 years, regularly followed at the CNRSD and having accepted the interview by a survey sheet. Excluded were patients with sickle cell trait genotype AS or AC or with a disability that prevented them from being interviewed. Results: Two hundred and fifty (250) patients with sickle cell disease were interviewed. The mean age was 29.1 years ± 11.12 years [17 years;67 years] and the sex ratio = 0.52. Nine patients over ten (9/10) attended at least secondary school. The jobless represented 25.60% of the total population followed respectively by students and laborers in 20.40% and 16% of cases. Twenty-four percent (24%) of patients were followed up in ophthalmology department. Statistically, there was no significant relationship between level of education (p = 0.4083), occupation (p = 0.6441) and knowledge of the ocular complications of sickle cell disease. Statistically, there was a significant relationship between knowledge of the ocular complications of sickle cell disease and compliance with ophthalmological follow-up (p = 0.0009). Conclusion: The knowledge of eye disorders related to sickle cell disease by patients with sickle cell disease improves their ophthalmological follow-up. Greater awareness on eye disorders related to sickle cell disease by medical staff towards patients with sickle cell disease would improve ophthalmological follow-up. .
文摘Hepatitis B virus (HBV) infection is a major public health problem worldwide. The aim of this study was to document the dynamics of HBV viral load during the follow-up of chronic hepatitis B patients at the Saint Camille Hospital in Ouagadougou (HOSCO) from 2017 to 2021. This descriptive retrospective study was carried out in the Hepato-Gastro-Enterology Department of HOSCO and focused on patients who were undergoing treatment for chronic viral hepatitis B. A total of 260 cases of chronic hepatitis B were included in the study. The most affected age group was 21 to 30 years, accounting for 48.08% of the cases. Lifestyle factors included alcohol consumption (3.08%) and tobacco use (2.69%). Major risk factors for transmission included lack of vaccination (98.46%), family history of HBV infection (68.00%) and engagement in high-risk activities (28.00%). Patients requiring treatment were prescribed Tenofovir 300 mg tablets. FibroScan<sup>®</sup> showed the presence of stage F3-F4 fibrosis (2.14%) and S3 steatosis (13.33%). After one year of follow-up, 6.92% of patients achieved an undetectable viral load with normalized transaminase levels. The majority of other patients had a detectable viral load but below 20,000 IU/mL. The prevalence of viral hepatitis B remains significant worldwide. Although effective and well-monitored treatment can lead to undetectable viremia, prevention remains the most effective strategy for successful management of this disease.
文摘Objective: The aim of this study was to describe the use of the postpartum intrauterine device in the maternity ward of the Ratoma communal medical center in Conakry. Methods: This was a descriptive cross-sectional study carried out between July 1<sup>st</sup> 2015 and June 30 2016, i.e. a duration of one year. Results: A total of 551 patients received advice on various contraceptive methods. Most of this advice was given in the post-partum period (40.2%) and during antenatal care (39.1%). Of the patients advised, 87 (15.8%) used the intrauterine device. The majority of users (93%) were married and uneducated (63.2%), and 39.1% were poor. The majority (56.3%) of intra-uterine devices were inserted in the immediate post-partum period. The majority of women had no adverse events either during the first six weeks (n = 57;65.5%) or at 3<sup>rd</sup> months (n = 75;86.2%) or 6<sup>th</sup> months (n = 76;87.4%) after IUD insertion. Most users remained complication-free throughout the follow-up period (n = 76;87.4% at 6<sup>th</sup> weeks and 3<sup>rd</sup> months, and n = 77;88.5% at 6<sup>th</sup> months). The continuation rate was 89.7% at 6 weeks and 3<sup>rd</sup> months, and 87.4% at 6<sup>th</sup> months after insertion. The majority of users (87.0%) were satisfied with the care they received. Conclusion: This study showed very few complications among intrauterine device users, and high continuation and satisfaction rates. The intrauterine device is a long-acting, effective, reversible and safe contraceptive that can be used by most women for birth spacing in Guinea, where women do not regularly visit health facilities.
文摘Congenital pure kyphosis due to failure of vertebral body segmentation is a relatively rare entity, and surgical intervention is infrequent compared to that for failure of vertebral body formation [1] [2]. There are very few reports of long-term follow-up of surgical treatment in patients with congenital pure kyphosis, and all the reported cases were diagnosed as failure of formation and had an age at the time of surgery of less than 18 years. It is important for orthopedic surgeons to follow the postoperative course of rare cases over 30 years. Here, we present a surgically treated case with ultra-long term follow-up of a 50-year-old patient with congenital pure kyphosis of the lumbar spine. Imaging of the lumbar spine showed six vertebrae and an unsegmented bar at L3-4 causing a pure kyphosis of 54°. The wedge-shaped block vertebra had 4 pedicles with the neural foramen between the pedicles without concomitant disc space, with compensatory thoracic hypokyphosis and lower lumbar hyperlordosis. One-stage correction and fusion surgery using anterior opening and posterior closing osteotomy was successfully performed. Both clinical and radiographic results were excellent and have been maintained for over 30 years postoperatively. The basic principle in the surgical treatment of adult spinal deformity is to achieve and maintain a good global sagittal balance over time. This case reaffirms the importance of spinopelvic harmony.
文摘Background and objectives: Breast Imaging Reporting and Data System in Category 3 (BIRADS-3) includes probably benign lesions which need a short-term imaging follow-up. However, in our context, the lesions graded BIRADS-3 remain insufficiently evaluated. We therefore conducted this study to assess the cancer occurrence and associated factors in BIRADS-3 lesions during the follow-up in order to propose an adaptation of the management for lesions in this category in our setting. Patients and methods: A retrospective longitudinal study of patients with lesions initially classified as BIRADS-3 and who realised each at least one additional imaging check-up between January 2014 and December 2022 in five Yaoundé hospitals. All clinical and imaging data were analysed using SPSS<sup>®</sup> 21.0 software with a significant p-value Results: Patients were aged 13 to 73 (33.0 ± 13.4) years, with a history of breast mass (315 cases;79.7%), breast pain (25 patients;6.3%), nipple discharge (20 patients;5.1%) or past family history of breast cancer (25 cases;6.3%). The most common baseline abnormalities were mammogram opacities (64.8%) and microcalcifications (48.6%), whereas initial breast ultrasound showed solid masses (77.0%) and cystic lesions (11.1%). Compliance with imaging appointment periods was low with only 23.9% of all patients performing an imaging control at the scheduled moment. During the follow-up, 115 patients (29.1%) were upgraded to BIRADS-4 and histology performed revealed 43 cancers (10.9% of overall initial BIRADS-3 sample). The presence of malignancies was associated to age above 40 years (p = 0.0001) and to the presence of nipple discharge (p = 0.0375). Conclusion: The frequency of malignancies among initial BIRADS-3 lesions in our series is higher than that described in the guidelines. This study highlights the need to be more proactive in the management of BIRADS-3 lesions in our setting as the compliance with follow-up is low. So, biopsy should be considered as an alternative to long-term follow-up for patients above 40, non-compliant with imaging check-ups and presenting with nipple discharge.
