Development Trend Research Articles

Occupational and Environmental Health Hazards among Agriculture Laborers: An Evidence-Based Study from Punjab, Pakistan

Laborers from the agriculture sector have often been victims rather than beneficiaries of the green revolution, technological development, and globalization trends that characterized the 20th century. In recent decades, the laborers working in the agriculture sector have been half of the world’s labor force, with an estimated number of 1.3 billion worldwide, and a majority of them found in developing countries. Adequate balance between agricultural growth and protection from occupational & environmental health hazards is very crucial for the future of the world’s food production and for the sustainability of the sector. The study was conducted in three divisions of Punjab, and primary data was collected through multistage simple random sampling techniques. The interview schedule was used as a tool for data collection. The results revealed that the occupational and environmental circumstances of the laborers were not conducive towards their health and well-being. The agricultural laborers have to face many health hazards, whereas the majority of the laborers were exploited only due to their illiteracy and ignorance about Government policies and laws related to them. A huge proportion of the participants reported chronic health, malnutrition, and socio-economic problems significantly associated with their working environment, amenities and available facilities.

Occupational and Environmental Health Hazards among Agriculture Laborers: An Evidence-Based Study from Punjab, Pakistan

Laborers from the agriculture sector have often been victims rather than beneficiaries of the green revolution, technological development, and globalization trends that characterized the 20th century. In recent decades, the laborers working in the agriculture sector have been half of the world’s labor force, with an estimated number of 1.3 billion worldwide, and a majority of them found in developing countries. Adequate balance between agricultural growth and protection from occupational & environmental health hazards is very crucial for the future of the world’s food production and for the sustainability of the sector. The study was conducted in three divisions of Punjab, and primary data was collected through multistage simple random sampling techniques. The interview schedule was used as a tool for data collection. The results revealed that the occupational and environmental circumstances of the laborers were not conducive towards their health and well-being. The agricultural laborers have to face many health hazards, whereas the majority of the laborers were exploited only due to their illiteracy and ignorance about Government policies and laws related to them. A huge proportion of the participants reported chronic health, malnutrition, and socio-economic problems significantly associated with their working environment, amenities and available facilities.

Robotics in dental and facial esthetics

Dental and facial esthetics is an essential part of modern stomatology. With the development of science and technology and the advancement of interdisciplinary studies, the research of robot technology in the field of dental and facial esthetics is becoming more extensive, and its clinical applications are gradually increasing. This article provides insights into the research and application of robot technology in dental hard tissue esthetics, periodontal soft tissue esthetics, dentition space esthetics, and maxillofacial esthetics. It also highlights the current limitations and development trends and provides references for future research and application of robots in oral esthetics.

Two Decades of Publications in Journals Dedicated to Autoimmunity: A Bibliometric Analysis of the Autoimmunity Field from 2004 to 2023

To carry out an in-depth analysis of the scientific research on autoimmunity, we performed the first bibliometric analysis focusing on publications in journals dedicated to autoimmunity (JDTA) indexed by science citation index during the period 2004–2023. Using bibliometric analysis, we quantitatively and qualitatively analyzed the country, institution, author, reference and keywords information of publications in JDTA, so as to understand the quantity, publication pattern and publication characteristics of these publications. The co-occurrence networks, clustering map and timeline map were created by CiteSpace and VOSviewer software to visualize the results. The CiteSpace was also used to analyze the strongest citation burst of keywords, which could describe the frequency, intensity and time period of high-frequency keywords, and indicate the research hotspots in the field. A total of 5 710 publications were analyzed, and their annual distribution number was basically stable from 2004 to 2023, fluctuating around 300. The United States and Italy led the way in terms of the number of publications, followed by France and China. For international cooperation, the developed countries represented by the United States cooperate more closely, but the cooperation was localized, reflecting that there was no unified model of autoimmunity among countries. UDICE-French Research Universities had the greatest number of publications. Subsequently, the number of publications decreased slowly with the ranking, and the gradient was not large. Eric Gershwin and Yehuda Shoenfeld stood out among the authors. They had an excellent academic reputation and great influence in the field of autoimmunity. The results of keyword analysis showed that JDTA publications mainly studied a variety of autoimmune diseases, especially SLE and RA. At the same time, JDTA publications also paid special attention to the research of cell function, autoantibody expression, animal experiments, disease activity, pathogenesis and treatment. This study is the first to analyze the publications in JDTA from multiple indicators by bibliometrics, thus providing new insights into the research hotspots and development trends in the field of autoimmunity.

Experimental study on the flexural performance of FRP grid-reinforced ultra-high-performance concrete I-beams with different steel fiber contents

To adapt to harsh engineering environments, the use of structural components with fiber-reinforced polymer (FRP) grid-reinforced ultra-high-performance concrete (UHPC) is considered a new development trend. Twelve FRP grid-reinforced UHPC I-beams are fabricated to investigate the effects of the thicknesses of FRP grids (0 mm, 1 mm, 3 mm, and 5 mm) and the steel fiber contents of UHPC (0%, 1%, and 2%) on their flexural performance. Four-point bending tests are conducted to obtain the failure modes, load-deflection characteristics, and strain responses of each testing beam, and a simplified calculation method for cracking loading and flexural bearing capacity is proposed. The results reveal that the increase in FRP grid thickness, the ultimate load bearing capacity of FRP grid-reinforced UHPC structural beams increases and the ductility also can be enhanced. The presence of steel fiber effectively inhibits the cracking and increases the first cracking load of the beam during the test process, although its influence on the ultimate bearing capacity is limited. Besides, until to the cracking stage, there is no noticeable change in the tensile strain of the FRP grids as the applied load increases. It has been used to simplify theoretical calculations, which shows good agreement with the experimental results.

Research on the generation and annotation method of thin section images of tight oil reservoir based on deep learning

The cast thin sections of tight oil reservoirs contain important parameters such as rock mineral composition and content, porosity, permeability and stratigraphic characteristics, which are of great significance for reservoir evaluation. The use of deep learning technology for intelligent identification of thin section images is a development trend of mineral identification. However, the difficulty of making cast thin sections, the complexity of the making process and the high cost of thin section annotation have led to a lack of cast thin section images, which cannot meet the training requirements of deep learning image recognition models. In order to increase the sample size and improve the training effect of deep learning model, we proposed a generation and annotation method of thin section images of tight oil reservoir based on deep learning, by taking Fuyu reservoir in Sanzhao Sag as the target area. Firstly, the Augmentor strategy space was used to preliminarily augment the original images while preserving the original image features to meet the requirements of the model. Secondly, the category attention mechanism was added to the original StyleGAN network to avoid the influence of the uneven number of components in thin sections on the quality of the generated images. Then, the SALM annotation module was designed to achieve semi-automatic annotation of the generated images. Finally, experiments on image sharpness, distortion, standard accuracy and annotation efficiency were designed to verify the advantages of the method in image quality and annotation efficiency.

Global Trends in mHealth and Medical Education Research: Bibliometrics and Knowledge Graph Analysis.

Mobile health (mHealth) is an emerging mobile communication and networking technology for health care systems. The integration of mHealth in medical education is growing extremely rapidly, bringing new changes to the field. However, no study has analyzed the publication and research trends occurring in both mHealth and medical education. The aim of this study was to summarize the current application and development trends of mHealth in medical education by searching and analyzing published articles related to both mHealth and medical education. The literature related to mHealth and medical education published from 2003 to 2023 was searched in the Web of Science core database, and 790 articles were screened according to the search strategy. The HistCite Pro 2.0 tool was used to analyze bibliometric indicators. VOSviewer, Pajek64, and SCImago Graphica software were used to visualize research trends and identify hot spots in the field. In the past two decades, the number of published papers on mHealth in medical education has gradually increased, from only 3 papers in 2003 to 130 in 2022; this increase became particularly evident in 2007. The global citation score was determined to be 10,600, with an average of 13.42 citations per article. The local citation score was 96. The United States is the country with the most widespread application of mHealth in medical education, and most of the institutions conducting in-depth research in this field are also located in the United States, closely followed by China and the United Kingdom. Based on current trends, global coauthorship and research exchange will likely continue to expand. Among the research journals publishing in this joint field, journals published by JMIR Publications have an absolute advantage. A total of 105 keywords were identified, which were divided into five categories pointing to different research directions. Under the influence of COVID-19, along with the popularization of smartphones and modern communication technology, the field of combining mHealth and medical education has become a more popular research direction. The concept and application of digital health will be promoted in future developments of medical education.

Effects of chemical pre-treatment methods combined with electron beam irradiation on the quality of “Edor” longan

Using electron beam (EB) radiation as a quarantine treatment when exporting fresh fruit is a development trend in the world. In this study, the effect of EB irradiation treatment in the quarantine dose (400 to 1000 Gy) on the quality of export "Edor" longan was investigated. Investigation of chemical pre - treatments measure combined with EB irradiation to decrease pericarp browning of longan has also been carried out. “Edor” longan were treated by SO2 fumigation or dipping in 1,5 N HCl solution for 20 min after EB irradiation at low quarantine dose (400 Gy). Untreated and non-irradiated fruits were used as control. That all were then stored assumed commercial conditions (25-26°C). The results showed that the treated samples delayed a decrease in the total phenolic content and had lower pericarp browning than control. In addition, the treated samples were no significantly difference in terms of weight loss, TSS, total acid content, vitamin C, ... compared with the control. In particular, the treated samples had delayed the degree of damage level due to rotting when extending shelf life up to 22 days compared the control (12 days). Therefore, the method of combining SO2 fumigation treatment with EB irradiation (400 Gy) can be used for quarantine treatment of export "Edor" longan; and treatment with 1,5 N HCl solution can be considered to replace the traditional SO2 fumigation method.

Exploring Trends and Challenges in Professional Development of Adult Educators across European Member States: Insights and Recommendations for Improvements

This article provides an overview of professional development trends in European Member States, encompassing training and qualification requirements, as well as the supply and demand for adult teaching staff, including specialized training in andragogical studies. The study investigates actions and policies related to professional development in selected European Member States through thematic analysis of a supportive document for National Coordinators of Adult Learning, who participated in an online Peer Learning Activity (PLA) in May 2021. Additionally, relevant information from Eurydice, European policy documents, scholarly articles, and research papers is incorporated. This overview sets the stage for a discussion on prevailing trends in the professional development of adult educators across European Member States and explores how these trends impact professional development. Overall, the discussion underscores the need for a more systematic and sustained approach to professional development and professionalization in the field of adult education. This includes addressing the diverse needs of adult educators and advocating for greater recognition and regulation of the profession across European countries.

A Review of Endogenous Security Research

The development of society has deepened the application of the Internet in production and daily life. At the same time, network security risks are becoming increasingly severe. For the security problems faced in cyberspace, most of the traditional defenses are currently focused on blocking the discovered vulnerabilities. However, these methods not only rely on prior knowledge of vulnerabilities but also fail to address the security issues brought about by the protection program itself. In view of this, endogenous security, which emphasizes the importance of not relying on a priori knowledge and not bringing in new security problems, has received increasing attention. This review provides a detailed introduction to endogenous security and its related issues, which is lacking in the field of network security. Firstly, this paper outlines the detrimental effects of vulnerabilities, identifies issues within moving target defense, and contrasts it with mimic defense. Additionally, the concepts, models, principles, and application scenarios of endogenous security are introduced. Finally, the challenges encountered by this technology are comprehensively summarized, and potential future development trends are further explored.

Integration Construction of Hybrid Electrocatalysts for Oxygen Reductions.

There has been notable progress in the development of efficient oxygen reduction electrocatalysts, which are crucial components of fuel cells. However, these superior activities are limited by imbalanced mass transport and cannot be fully reflected in actual fuel cell applications. Herein, we present the design concepts and development tracks of platinum-nanocarbon hybrid catalysts, aiming to enhance both cathodic electrocatalysts and hydrogen reactors. This review commences with an introduction to Pt/C catalysts, highlighting the diverse architectures developed to date, with particular emphasis on heteroatom modification and microstructure construction of functionalized nanocarbons based on integrated design concepts. This discussion encompasses the structural evolution, property enhancement, and catalytic mechanisms of Pt/C-based catalysts, including rational preparation recipes, superior activity, strong stability, robust metal-support interactions, adsorption regulation, synergistic pathways, confinement strategies, ionomer optimization, mass transport permission, multidimensional construction, and reactor upgrading. Furthermore, this review explores the low-barrier or barrier-free mass exchange interfaces and channels achieved through the impressive multidimensional construction of platinum-nanocarbon integrated catalysts, with the goal of optimizing fuel cell efficiency. In conclusion, this review outlines the challenges associated with platinum-nanocarbon integrated catalysts and provides perspectives on the future development trends of fuel cells and beyond. This article is protected by copyright. All rights reserved.

A new method of rapid-intelligent assessment for the dynamic service performance in high-speed railway subgrade

ABSTRACT There is a lack of a rapid, advanced, and comprehensive method for assessing the dynamic service performance in high-speed railway subgrade, which leads to an inability to pre-assess the health state of the subgrades in advance. In this paper, an innovative method of rapid-intelligent assessment for the dynamic service performance (RADSP) in high-speed railway subgrade was proposed. Firstly, a large-scale exciter was used to simulate the train loading effect, which could rapidly obtain the assessment metrics for subgrade dynamic service performance, including subgrade dynamic response (SDR) and subgrade cumulative deformation (SCD), where the SDR includes dynamic stress and acceleration. Then, to explore the future development trend of SCD during operation, an intelligent and advanced prediction of SCD was conducted using the optimal machine learning (ML) prediction model. Finally, by combining the results of the SDR and SCD assessments to achieve the RADSP in high-speed railway subgrade. Moreover, the method was applied to assess the dynamic service performance of diatomaceous earth subgrade structures with four different waterproofing structure layers (WSL): the middle of subgrade surface layer (WSL-1), the bottom of subgrade surface layer (WSL-2), the middle of subgrade bottom layer (WSL-3), and the bottom of subgrade bottom layer (WSL-4). The results indicate that: 1) During the excitation experiments, the maximum values for SDR (dynamic stress, acceleration) and SCD exceed the respective limits of 50 kPa, 10 m/s2, and 15 mm under WSL-1 and WSL-4. 2) The ensemble model, AdaBoost-GPR, is selected as the optimal ML model to predict the SCD values. Notably, the prediction SCD value exceeds the 15 mm limit under WSL-3, indicating that the SCD during future operation does not meet the requirements for pre-assessment. 3) Under WSL-2, both SDR and SCD assessments satisfy the limit value requirements, indicating that the dynamic service performance is better. Based on the proposed method, it is found that when designing waterproof-drainage subgrade structures in diatomaceous earth areas, it is recommended to position the WSL at the bottom of subgrade surface layer. The research findings serve as a crucial reference and valuable lesson for the health monitoring of high-speed railway subgrades.

Electrical Engineering and Intelligent Control Strategies in Renewable Energy Integration: Enhancing Energy Sustainability

This paper discusses in detail the important role and application value of electrical engineering and intelligent control strategies in the integration of renewable energy, and proposes the viewpoints of improving the utilization rate of renewable energy and ensuring the stability of energy systems through electrical engineering and intelligent control strategies. At the same time, it also looks forward to the future development trend.

Deep transfer learning strategy in intelligent fault diagnosis of rotating machinery

Rotating machinery plays an essential part in many engineering fields. It needs prompt solutions to the prognosis and health management to ensure the system reliability. Facilitated by big data and artificial intelligence, intelligent fault diagnosis provides a new approach. As for the insufficient faulty data and complex conditions, deep transfer learning (DTL) presents a possible approach for cross-domain and cross-machine diagnosis. The published reviews thus far mainly emphasize on the analysis of fault diagnosis based on common classes of DTL or industrial application scenarios. This review concentrates on the applications of DTL in rotating machinery. Moreover, present relevant reviews were mainly till the end of 2021. The latest researches are analyzed from then until now. A special main line based on input types is chosen that distinguishes it from other reviews. From this perspective, it is therefore valuable to comprehensively investigate the fault diagnosis of rotating machinery. This survey firstly outlines the fundamental principle and conventional categories of DTL. The primary applications of DTL in fault diagnosis of rotating machinery are then summarized, and more than 100 relative studies have been analyzed. The special perspective of input types is selected and evaluated, including one-dimensional and two-dimensional, on the DTL framework as applied to the rotary machines discussed. Finally, the existing challenges are pointed out and potential future trends of DTL are prospected. This review helps readers to understand the research status and development trends of transfer intelligent fault diagnosis. It serves to the innovative exploration from multiple different scales.

3D scanning techniques in power engineering

Information about component geometry is a key parameter for assessing residual life and monitoring degradation processes during the life cycle of a technology. High-precision optical measurement systems are complex metrology devices that enable the collection of complex data on the physical properties of components and their rapid evaluation in CAD-based programs. These solutions offer an analysis of changes in component characteristics over time and comparing them with as-built documentation. The quality of production can be evaluated by comparing the condition of the equipment with the product documentation or monitoring the influence of service conditions on the degradation of the equipment and the trend of future development of defects. All this in digital form of data, which enables new progressive approaches to repair and maintenance programs of monitored equipment. The use of advanced metrology and diagnostic systems and the procedures they offer can reduce the time required for measurement by conventional methods and multiply the data yield from metrology, which in conjunction with modern IT technologies can detect new degradation mechanisms and increase safety service and extend projected lifetime. Up-to-date technology data can significantly save on maintenance costs or even eliminate maintenance procedures. It also provides important data for the setup of LTO.

Adapting a prescreening program from VHIO to match molecular alterations in over 10,000 patients' tumors with targeted agents and immunotherapies in early clinical trials.

e23071 Background: VHIO's Molecular Prescreening Program (MPP) began in 2010 to catalyze precision medicine at the institution. Over the last decade, this program has provided access to advanced molecular diagnostics to more than 10,000 cancer patients (pts) and is critical in matching targeted therapeutic approaches to clinical trials (CTs). Here we report the clinical utility of our program given the evolving molecular testing landscape and trends in drug development. Methods: We assess the adoption and impact of the VHIO’s MPP in CTs recruitment. All tests were developed in-house: a. from 2010 to 2014 we used formalin fixed paraffin embedded tumor samples to test for hotspot mutations (Sequenom, 20 oncogenes) plus FISH/IHC of selected markers; b. from 2015 to 2017 we moved to a amplicon-based NGS panel (MiSeq, 61 genes), a copy number alteration (CNA) panel (Nanostring, 44 genes) and a fusion + gene expression assay (Nanostring, 26 genes) with additional FISH/IHC in selected cases, including PDL1 and MSI status; c. since 2019, we use a custom capture-based NGS assay for mutations (mut), CNA and Tumor Mutation Burden (TMB) estimation (NextSeq, 435 genes); d. since 2022, we run a liquid biopsy panel in-house (Guardant360, technology transfer). Results: We found a stepwise increase in the MPP adoption, from 207 pts in 2010 to 1,965 pts in 2023, representing almost a tenfold increase. Most common tumours analysed were colorectal, lung, breast, gynaecologic, pancreato-biliary, and gastric. The number of CTs requiring biomarker match has increased from 13 in 2010 to more than 201 in 2023, the most frequent in the last year being HER2 (33), PDL1 (20), EGFR (17), RAS (15) and FGFR (9), MSI (9) and ALK (7). In 2023, 1,230 patients had broad tissue NGS panel, 1,235 were tested with IHC, 373 with fusions + expression assay and 991 with liquid biopsy. Inclusion rate in CTs with biomarker match has fluctuated between 13% and 19% in the past 5 years. Overall, close to 50% of these trial recruitments are with genomically-informed enrichment strategies and not mandatory inclusion criteria. On average, 20% of the patients were still enrolled in unmatched trials after molecular testing. Conclusions: The success of VHIO's MPP is related to agile innovation and clinical deployment of new technologies in a timely manner, critical for the development of new drugs in CTs. Biomarker matched trials evolved from a “few targets/ large populations” scenario to a complex situation with “many targets/ small populations”. Many pts benefit from enrichment strategies in Phase 1 CTs. The impact of the recent implementation of liquid biopsy and ongoing development of genomic + transcriptomic signatures will be closely monitored.

A sustainability-oriented approach for performance assessment of existing buildings and a case study

The practice of sustainable buildings has become a general trend in urban development. Yet, with the rapid development of urban renewal, the performance of existing buildings often fails to meet the actual needs of sustainable urban development. To improve the performance of existing buildings, it is urgently needed to transform the existing structures and upgrade their functions and facilities. However, the pertinent guidelines have often been unclear for assessing the performance of existing structures, and a sounder and quantitative sustainable performance assessment approach has been lacking to guide decisions on the restoration, protection, or demolition of existing buildings. Based on a multi-expert consultation methodology, we proposed a revised flexible comprehensive assessment system and a comprehensive sustainability assessment approach. The system includes 4 categories, 7 quantitative and 47 qualitative indicators. Specifically, the assessment system involves a series of steps: 1) building a hierarchical model, 2) defining assessment indicators/items and constructing a judgment matrix, 3) determining the weight coefficients of the indicators, 4) collecting/calculating quantitative and qualitative data, 5) analyzing the data and results, and 6) drawing the assessment conclusions. A case study was presented to demonstrate the application of the approach. Compared to current practices, this comprehensive assessment system may serve as a scientifically sounder and quantitative approach to guide sustainable development of existing urban buildings.

Combining Google Earth historical imagery and UAV photogrammetry for urban development analysis

Rural-urban migration often triggers additional demand for housing and infrastructural development to cater for the growing population in urban areas. Consequently, town planners and urban development authorities need to understand the urban development trend to make sustainable urban planning decisions. Yet, methods to analyse changes and trends in urban spatial development are often complex and require costly data collection. This article thus presents a simplified method to analyse the urban development trend in an area. The method integrates Google Earth (GE) historical imagery (baseline data) and unmanned aerial vehicle (UAV) photogrammetry (recent data) to quantify the changes over time. This approach can be applied to study the urban development trends in low-income countries with budget constraints. The method is discussed under four main headings: (1) background, (2) method details, (3) limitations, and (4) conclusion.•Google Earth historical image can be extracted with its associated world file.•The population of an area can be estimated by using average household size data and the number of residential buildings in the area.•The building height ratio can be used to ascertain if the land is being used parsimoniously.

Research on Failure Pressure of API 5L X100 Pipeline with Single Defect

Background: With the continuous application of API 5L X100 high-strength grade steel pipeline and the development trend of increasing pipeline diameter and design pressure in China's long natural gas and petroleum pipeline, API 5L X100 high-strength grade steel pipeline steel is bound to become the aorta in long-distance pipeline construction in the future. Studying the failure pressure of API 5L X100 high-strength grade steel pipeline has high economic and social benefits. Objective: Exploring the corrosion mechanism of the two single corroded pipeline models with outer defect and inner defect. Methods: Using ANSYS Workbench 15.0 software to explore the two single corroded pipeline models with outer defect and inner defect and the influence of geometric parameters such as defect depth, defect length, defect width, etc., on the maximum equivalent stress and failure pressure investigated. Based on the finite element analysis database, the failure pressures of two single corroded pipeline models were fitted using Matlab software and the fitting formulas. Results: In the corrosion defect area of the pipeline, stress concentration occurs; Far away from the corrosion defect area, the stress distribution is uniform. For the pipeline model with outer defect and inner defect, as the defect depth and length increases, failure pressure shows a decreasing trend and is almost unaffected by defect width; As the ratio of diameter to thickness increases, failure pressure shows a decreasing trend; By fitting failure pressure formula of the pipeline models with outer defect and inner defect, a multivariate fitting function formula of failure pressure is obtained, with high fitting exactitude. Conclusion: The conclusion obtained have certain guiding values for the normal and stable operation of natural gas and petroleum transportation pipelines.

Integrated transcriptomics and metabolomics study of embryonic breast muscle of Jiaji ducks

Because number of matured muscle fibers in poultry does not increase after birth, the meat yield is mainly determined during embryogenesis. We previously indicated breast muscle grew rapidly from 18th day after hatching (E18) to E27, and almost stopped from E27 to E34 of Jiaji ducks, while the mechanism is unclear. This study utilized RNA-seq to explore the related genes of muscle development and their relationship with small molecule metabolites at E18, E27 and E34 of Jiaji ducks. Several thousand differentially expressed genes (DEGs) were detected among E18, E27 and E34. DEGs expression profiles included 8 trend maps, among which trend 1 was opposite to and trend 6 was consistent with breast muscle development trend of Jiaji ducks. Through joint analysis between trend 1 of DEGs and trend 1 of differential metabolites (DEMs), protein digestion and absorption pathway stood out. The decrease of COL8A2 gene expression will lead to the decrease of arginine content, which will inhibit the development of breast muscle in embryonic Jiaji duck. Similarly, joint analysis between trend 6 of DEGs and trend 6 of DEMs indicated the increase of GAMT gene expression will cause the increase of proline content, and then promote the development of breast muscle of Jiaji duck in embryonic period. These results will be helpful for further understanding the mechanism of muscle yields of Jiaji ducks.