Pedestrian dead reckoning (PDR) using inertial sensors has paved the way for developing several approaches to step length estimation. In particular, emerging step length estimation models are readily available to be utilized on smartphones, yet they are seldom formulated considering the kinematics of the human body during walking in combination with measured step lengths. We present a new step length estimation model based on the acceleration magnitude and step frequency inputs herein. Spatial positions of anatomical landmarks on the human body during walking, tracked by an optical measurement system, were utilized in the derivation process. We evaluated the performance of the proposed model using our publicly available dataset that includes measurements collected for two types of walking modes, i.e., walking on a treadmill and rectangular-shaped test polygon. The proposed model achieved an overall mean absolute error (MAE) of 5.64 cm on the treadmill and an overall mean walked distance error of 4.55% on the test polygon, outperforming all the models selected for the comparison. The proposed model was also least affected by walking speed and is unaffected by smartphone orientation. Due to its promising results and favorable characteristics, it could present an appealing alternative for step length estimation in PDR-based approaches. The continuous advances in the field of microelectromechanical technology have led to the mass production of sensors. Inertial sensors are becoming ubiquitous as many applications are readily available . Their pApproaches to PDR determine the current position by estimating the change in the previous position, usually based on step length and heading. In particular, a range of different techniques is known to be employed for the step length estimation process. Various machine learning techniques and statistical estimation methods are often used to achieve higher accuracy, yet they depend upon comprehensive training. For instance, artificial neural networks  and BayeStep length estimation models usually calculate step length based on a linear combination of inertial sensor measurements, such as step frequency or acceleration. Some models exploit the relationship between step length and step frequency ,49,50,51In one of our previous studies, we conducted an in-depth analysis and comparison of representative step length estimation models and demonstrated that the performances of certain models change under different evaluation protocols when smartphone placements and walking speeds vary in trials . MoreoveFor these reasons, we aimed to investigate the possibilities of extending the acceleration-based model we proposed in our previous work when considering the movement of anatomical landmarks during walking . As the Proposing a new step length estimation model typically entails a two-stage process consisting of a derivation and evaluation of the model. The scope of the former stage often combines inertial sensor data acquisition and analysis of these data. Obtained insights from this analysis lay the basis for a new model, which is evaluated next. Evaluation datasets are usually larger and more diverse between trials in terms of sensor position, terrain, walking speed, and duration. In our previous work, we derived a new model by identifying similar characteristics of the movement of anatomical landmarks by means of the kinematics of the human body during walking . The proThe aim of this work was to eliminate previously identified limitations of the model , i.e., ri, yi, zi), 1 ≤ i ≤ 8. Experimental protocol and data analysis are presented in detail in our previous work , and onli, yi, zi), 9 ≤ i ≤ 20, were measured on the treadmill. The reference stride lengths were calculated from the spatial positions of the infrared marker M7. For the evaluation of the proposed model, we used the publicly available dataset  that we The selection of walking speeds for the treadmill experiments was based on our previous study, in which experimentation included measuring the free walking of healthy adults . Hereby,Ten persons (four women and six men) selected from a group of healthy adults participated in these experiments. This study aimed to investigate the possibilities of extending the acceleration-based model we proposed in our previous work . This moThe basis of this work presented the model that calculates step length Before utilizing CCA, relevant data were extracted from the measurements acquired by infrared markers attached to anatomical landmarks on the human body during walking. The motion of the infrared marker can be represented as a curve in space where its position is represented by three components corresponding to triaxial position coordinates that change with regard to time . If the Next, potential parameters were determined. Hereby, the aim was to select a number of relevant parameters that can be determined from inertial sensor measurements without too complex calculations, such as integration, to avoid potential errors being propagated in the process. Data were divided into two matrices, Since only tunable constants were included in matrix N strides. This approach is highly personalized as it takes into account each person separately, yet it can contribute towards estimating walked distance more accurately. It was, therefore, utilized in the evaluation of this study to lay the groundwork for the future work of determining the values of tunable constants by means of one of the gait authentication techniques that can present the potential to be generalized over similar gait patterns. In addition, it was observed that stride frequency and acceleration magnitude inputs are highly correlated to walking speed. Altogether, three walking speeds were tested during the experiments for the derivation of the model. Based on the average values of acceleration magnitude and stride frequency inputs, tunable constants The performance of the proposed model was evaluated utilizing the dataset from the publicly available benchmark repository for the evaluation of step length estimation models . This daThe models had to meet certain criteria in order to be considered for the selection to be implemented, evaluated, and compared to the proposed model. According to the first criterion, the predominant sensor inputs of the model have to include both acceleration and step frequency inputs. Another criterion was the fact of sufficient description for the implementation being present. As a consequence, several representative models were selected for the comparison, i.e., models proposed by Sharp and Yu , Shin anThese models were implemented and then evaluated using the publicly available dataset established in the scope of our previous work ,62. The As a result, the evaluation was conducted in two stages. In the first stage, data collected during the treadmill experiments were used. The first five minutes of data collected in each trial were utilized for the tuning of the models, while the remaining 10 min were utilized for the evaluation. Tunable constants of models were determined by employing the least square estimation method for each trial and smartphone position. One hundred and twenty sets of tunable constants were calculated for each model. In the second stage of the evaluation, the data collected on the polygon were used. The selected models were tuned by using the data collected during the first five minutes of the treadmill experiment. However, for each smartphone position and each person, the data collected for different walking speeds were joined. Again, the least square estimation method was used. Altogether, 40 sets of tunable constants were calculated.The performance of the models was calculated as follows. For the treadmill experiments, the performance of the models was calculated as the absolute difference between the estimated and measured stride lengths. Whereas for the test polygon experiments, the performance of the models Herein, we present the evaluation results with reference to MAEs, standard deviations (SDs), and coefficients of variation (CVs). First, we introduce the evaluation results of the treadmill experiments starting with the overall results and results for different smartphone positions and different walking speeds. Later, we present the evaluation results of the polygon experiments.To sum up, the proposed model yielded MAEs of 5.52 cm and 5.77 cm in the scope of overall evaluation when considering stride length underestimation and overestimation, respectively. The obtained CVs are also in line with the values of CVs produced by other models, as the values of CVs of the proposed model are not greater or lower than the minimum and maximum values of CVs produced by other models. Similar conclusions can be drawn for the SDs and the percentage shares of overestimation and underestimation produced by the proposed model as well. For these reasons, we do not distinguish between overestimated and underestimated stride lengths henceforth and only present the overall MAEs, corresponding SDs, and CVs for different walking speeds and smartphone positions. The results indicate that the proposed model outperformed other models in terms of the accuracy of stride length estimation for all walking speeds. It produced MAEs of 4.65, 5.64, and 4.99 cm for slow, normal, and fast walking speeds, respectively. Of note is that models yielded the most accurate results for normal walking speed on average. Notably, the model proposed by Shin and Park  demonstrThe obtained results indicate that the proposed model yielded the most accurate results for slow and fast walking speeds in terms of accuracy of stride length estimation. Nevertheless, it was slightly outperformed by the models proposed by Sharp and Yu  and ShinThe results indicate that the proposed model outperformed all the other models for slow and fast walking speeds in terms of accuracy of stride length estimation, whereas the model proposed by Sharp and Yu  achievedThe results indicate that our proposed model outperformed all the other models selected for comparison in terms of the accuracy of stride length estimation. The model proposed by Bylemans et al.  estimateThe results indicate that the proposed model outperformed all the models selected for the comparison for all smartphone positions in terms of accuracy of estimated walked distance on average. Notably, the model proposed by Sharp and Yu  producedWe discuss the evaluation results of the selected models herein. First, a comparison of models is accomplished based on their characteristics. Later, the evaluation results for the treadmill and polygon experiments are discussed, considering different walking speeds and smartphone positions. Finally, future research directions conclude this section. The outcome of this study is an enhanced step length estimation model that employs acceleration magnitude and step frequency inputs. Smartphone orientation does subsequently not affect step length estimation, unlike the models proposed by Mikov et al. , BylemanA number of models selected for the comparison are extensions of previously proposed models. The model proposed by Weinberg  laid theThe models also employ a different number of tunable constants. For instance, the models proposed by Mikov et al.  and ByleWhile all the models can be used in pedestrian navigation using inertial sensors, only the proposed model and the model proposed by Shin and Park  are unafThe overall results obtained from the treadmill experiment data indicate that the proposed model outperformed all the models selected for the comparison. The results achieved from the proposed model indicate that it outperformed all the models for slow and fast walking speeds and all smartphone positions in terms of stride length estimation accuracy. Similarly, it also outperformed the other models for a normal walking speed when considering smartphones attached to the upper arm and thigh, whereas the model proposed by Shin and Park  estimateThe walking speed affected the performance of the models. The models proposed by Shin and Park  and SharThe overall results indicate that the proposed model outperformed all the models selected for the comparison. It produced an overall MAE of 4.55%, which is more than two percent lower than the MAE of the second-best model proposed by Sharp and Yu . When coThe proposed model demonstrated consistent performance for different smartphone positions. The walking speed also had the lowest impact on our proposed model. In general, the models produced results that were distributed around the overall MAE when considering different smartphone positions. Notably, the model proposed by Bylemans et al.  achievedThe main findings of our study are as follows. The obtained results indicate that our proposed model outperformed the models selected for the comparison. Moreover, smartphone orientation has no effect on the proposed model due to the predominant inputs being acceleration magnitude and step frequency. As a consequence, no particular deliberation is needed for the smartphone placement on the person’s body. The proposed model can, therefore, represent a reasonable choice for estimating step length in PDR-based approaches. One limitation of this study is related to the absence of scenarios typical for smartphone users due to tracking the smartphone positions with the optical measurement system. Another limitation corresponds to the number of persons included in the experiments. The adaptive design of the proposed model is highly accurate, yet it is also highly personalized due to requiring it to be tailored for each individual. We have dedicated a certain amount of time to determine the optimal values of tunable constants, as they had to be calculated for different walking speeds. As a consequence, we applied the optimization method several times. Moreover, we also stored average acceleration magnitude values and stride frequency inputs for each walking speed, as they were used as the basis for the selection of tunable constants in the step length estimation procedure. Nevertheless, several studies have already proved that inertial sensors can be utilized for gait recognition . This isIn this paper, we presented an enhanced step length estimation model derived by means of CCA. Spatial positions of anatomical landmarks on the human body during walking, tracked by an optical measurement system, were utilized in the derivation process. The proposed model utilizes acceleration magnitude as well as step frequency inputs. Consequently, smartphone orientation does not affect the proposed model. When considering the average values of inputs, tunable constants can be dynamically determined for every predefined number of strides, thus enabling the model to adapt to changes in walking speed per person.We evaluated the proposed model by using a publicly available dataset  from our


The popularization of mobile health  apps for public health or medical care purposes has transformed human life substantially, improving lifestyle behaviors and chronic condition management.This review aimed to identify behavior change techniques (BCTs) commonly used in mHealth, assess their effectiveness based on the evidence reported in interventions and reviews to highlight the most appropriate techniques to design an optimal strategy to improve adherence to data reporting, and provide recommendations for future interventions and research.We performed a systematic review of studies published between 2010 and 2021 in relevant scientific databases to identify and analyze mHealth interventions using BCTs that evaluated their effectiveness in terms of user adherence. Search terms included a mix of general , computer science , and medicine  terms.This systematic review included 24 studies and revealed that the most frequently used BCTs in the studies were feedback and monitoring (n=20), goals and planning (n=14), associations (n=14), shaping knowledge (n=12), and personalization (n=7). However, we found mixed effectiveness of the techniques in mHealth outcomes, having more effective than ineffective outcomes in the evaluation of apps implementing techniques from the feedback and monitoring, goals and planning, associations, and personalization categories, but we could not infer causality with the results and suggest that there is still a need to improve the use of these and many common BCTs for better outcomes.Personalization, associations, and goals and planning techniques were the most used BCTs in effective trials regarding adherence to mHealth apps. However, they are not necessarily the most effective since there are studies that use these techniques and do not report significant results in the proposed objectives; there is a notable overlap of BCTs within implemented app components, suggesting a need to better understand best practices for applying (a combination of) such techniques and to obtain details on the specific BCTs used in mHealth interventions. Future research should focus on studies with longer follow-up periods to determine the effectiveness of mHealth interventions on behavior change to overcome the limited evidence in the current literature, which has mostly small-sized and single-arm experiments with a short follow-up period. In modern society, the rushed lifestyle and excessive adulteration in food products have caused health-related disorders, making them an inevitable part of modern life . This isBesides, smartphones have become an essential tool in our daily lives, impacting 7.2 billion users worldwide with more than 70% of them in low- and middle-income countries . SmartphRecently, the popularization of mHealth apps for public health or medical care purposes have transformed human life substantially. Strategies such as reminders, counselling, reinforcement, or education have been used to improve people’s adherence to the app, thus improving lifestyle behaviors  and chroThere is a need to improve the adherence to one’s well-being, regular health monitoring, and expert involvement . The WormHealth has the potential to improve lifestyle and CCM, and can be rapidly adopted on a large scale and at low cost , but incAlthough the reviews include mHealth studies for a specific population, activity, or disease, most of these studies evaluated the effectiveness in terms of the results obtained for the intervention’s objective. Because of this, it is difficult to discern whether the intervention was ineffective due to a lack of adherence by participants or the combination of 35 BCTs being inadequate for the problem addressed. Therefore, the motivation of this systematic review is to identify current studies that have specifically reported their results in terms of adherence to extract the most used BCTs among the effective studies. This will help to design an adherence-focused strategy combining these BCTs.mHealth is a term used for mobile apps and other wearable devices that collect and monitor medical information from users [om users . Data coom users , and impom users . BCTs arom users —for whicom users ,27. BesiAdherence is defined by the WHO [ the WHO  as “the  the WHO . If peopThe objective of our systematic review is to identify and analyze relevant studies on BCTs used in mHealth interventions, focusing on the effectiveness of the BCTs on use and paying special attention to improve adherence to data reporting. Hence, the research questions (RQs) that have guided this review are:RQ1: What BCTs are most commonly used in the context of mHealth apps? How can these techniques be classified?RQ2: What is the performance of these techniques concerning end-user adherence?RQ3: Are BCTs  useful for improving adherence to data reporting in mHealth apps?This systematic review was conducted according to the PRISMA  statement . DetailsEligible studies were peer-reviewed articles published in English from January 1, 2010, to December 2021. With the growth of technology used for mHealth, the selected time allowed us to assess studies using the most relevant technologies. Participants in the studies were patients of any age, both healthy and with any type of chronic disease. Moreover, studies with interventions using health practices supported by any type of mobile device were eligible for inclusion. Besides, interventions could include multiple delivery methods and nondigital elements. The result assessed was adherence focusing on any outcome  measured by any metric during any follow-up period.The scientific databases selected for the review were Scopus, PubMed, Web of Science, and IEEE Xplore. The combination of these databases provides comprehensive coverage of publications in the context of medical informatics, high relevance, and a complete advanced search. Search strings and search methods were consistent across all databases.A preliminary literature review resulted in the first search equation, which aimed to find the different applications of mHealth in personalized medicine. This allowed us to identify relevant keywords and search terms to refine the search equation in each iteration by focusing on relevant topics such as adherence and data reporting but without limiting it to the field of personalized medicine. Finally, behavior change was found to be a popular aspect of improving adherence and hence the effectiveness of studies. We only included the term “behaviour change” because it is not limited to techniques, as there are different theories and models that contain them. As a result, four search iterations were performed. Those iterations are shown in After the initial gathering and screening of studies, articles were selected based on predefined eligibility criteria.The included studies meet the criteria of being an mHealth intervention. In addition, they fulfill at least one of the following conditions:The study implements at least one BCT.The study compares several BCTs.The study evaluates the BCTs using at least one adherence metric.The excluded studies meet at least one of the following conditions that aim to discard irrelevant studies for this systematic review:The study does not address the use of BCTs in the context of mHealth or vice versa.The study does not present at least one of its results in terms of adherence.The study was not published in between the years 2010-2021.The study does not belong to one of these categories: journal paper, conference paper, or review.The study was not peer reviewed.The study is not written in English or Spanish.PRISMA  guidelinThe behavioral strategy used in each study was identified and coded using the taxonomy of 18 categories introduced in the Background section to answer RQ1. To perform correct identification and coding, free taxonomy training was received using materials available online . ResultsThis section presents the results obtained from the methodology described in the Methods. First, an overview of the selected studies and their main characteristics is presented, and then an analysis of these studies is performed.The search results and study selection are summarized in the PRISMA flowchart in We summarized the selected 24 studies -53 to unWe observed in the reviewed papers that the most targeted behavior was medication adherence—present in 67% (n=16) of the studies—which is important in preventing rehospitalization, morbidity, mortality, and increased health care costs . We alsoRegarding adherence evaluation metrics, it is worth mentioning that different methods are used for this measurement, from daily use of the mobile app to the Morisky Medication Adherence Scale. To analyze these studies homogeneously, a cutoff point for effectiveness in terms of adherence rate was considered. High adherence was defined by an adherence rate ≥80% and nonadherent as an adherence rate <80%. This cut point is conventional in the adherence literature ,56 and iMoreover, after the BCTs used in each study were identified, we classified the studies into effective and ineffective using the cut point of 80% to gain further insight about why some interventions yielded significant improvements. As a result, This comparison revealed that, among the top five most used BCTs in the studies, feedback and monitoring (60%-40%) along with associations (57%-43%) have been used homogeneously in effective and ineffective studies, goals and planning (79%-21%) and personalization (71%-29%) have improved the effectiveness of the interventions since they have a higher presence in effective than in ineffective studies, and shaping knowledge (42%-58%) had a lower presence in effective than ineffective studies.It was observed that 2 of the main BCTs  used on effective interventions were present in 100% of the adherence-oriented studies for mobile apps and in none of the ineffective studies ,40,42,52feedback and monitoring, goals and planning, associations, shaping knowledge, and personalization. Similar BCTs were also found to be common in reviews of mHealth interventions targeting physical activity and sedentary behaviors, lifestyle, and medication adherence for CCM [We answered three RQs (defined in the Methods section) related to BCTs used in mHealth interventions. To answer RQ1, the taxonomy of BCTs, proposed by Michie et al  and whic for CCM ,60.For RQ2, the categories of BCTs with the highest presence in effective studies were goals and planning, associations, feedback and monitoring, and personalization (as described in the Results section). However, in line with other reviews that found mixed effectiveness in mHealth outcomes ,27, theyRegarding RQ3, considering the responses for RQ1 and RQ2, it was observed that, although some studies in the mHealth context have evaluated user adherence as a complementary outcome resulting from their implementation of BCTs, none of the reviewed studies applied BCTs for adherence to data reporting or use of the mHealth app; the studies generally aimed to improve outcomes for activity in chronically ill or healthy people. However, designing an approach that combines the BCTs most effective for adherence , previously identified in RQ2, could be helpful to improve data reporting in mHealth apps.Several limitations were found that are important to highlight. This review focused on mHealth interventions that include BCTs and how they affect user adherence. As a result, we found a lack of heterogeneity in the sample of results, evidencing that most of these interventions do not focus on improving user adherence to data reporting or to the app but rather on achieving an improvement in the objective of the study, whether it is an improvement in lifestyle behaviors or CCM.In addition, designing mHealth apps is relatively new, and there is little agreement regarding best practices. Researchers are still trying to understand how and why BCTs lead to positive health outcomes when delivered through apps. There is growing evidence to support the effectiveness of mHealth interventions on health outcomes. Even though the evidence is growing, it is still relatively weak. This may be in part due to the difficulty of designing and conducting rigorous studies on mHealth interventions, even more in the context of the COVID-19 pandemic.Additionally, the BCT taxonomy approach used to summarize the characteristics of interventions still has some limitations, despite the inclusion of the extension proposed by Dugas et al . This taFinally, we found that most studies are small single-arm studies with short follow-up periods. Future research should focus on studies with longer follow-up periods to determine the effectiveness of mHealth interventions on behavior change.mHealth interventions to improve lifestyle behaviors and CCM have become popular in recent years, improving along with different technologies. Although SMS text message–based mHealth interventions remained popular for their proven high results in terms of effectiveness, this review suggests that mHealth is progressively moving toward the implementation of mobile apps and wearable interventions, replacing SMS text messaging with notifications. This review also revealed that mHealth is being applied to address a diversity of lifestyle behaviors and health outcomes, showing its applicability to a variety of health care contexts, with one of its focuses being medication adherence. On the other hand, we found that the most frequently used BCTs in mHealth interventions were feedback and monitoring, goals and planning, associations, shaping knowledge, and personalization. However, this does not necessarily imply that they are the most effective, so we conducted further analysis that found that frequently used BCTs in ineffective studies are often well supported in the health behavior change literature ,62, suggCongruent with other reviews that found heterogeneous effectiveness of mHealth, the results also suggested that there remains a need to optimize the use of BCTs or find a better combination for better outcomes, it is intended that this review could help identify the most appropriate techniques to improve adherence to data reporting and thus design an optimal strategy while taking into account the differences among population subgroups, pointing to the need to go beyond the idea that “one-size-fits-all.” As a small step forward, more sophisticated technologies such as wearable activity trackers and wireless sensors have been included in mHealth interventions.


In recent years, copyright governance for short videos has become a hot issue of common concern in the academic community and the industry. Therefore, this study intends to explore the economic aspect of copyright governance in relation to the proliferation of infringing short videos. The short video industry of China has been taken as a case to demonstrate the copyright governance issue. Transaction cost theory has been applied to analyze the economic aspect of copyright governance in terms of four dimensions: bounded rationality, opportunism, environmental uncertainty, and asset specificity. From the perspective of transaction cost economics, the problem of short video infringement is observed to be essentially a market failure due to high transaction costs. In the short video market, substantial transaction costs are incurred in the legal transaction of copyright with these costs considered to be too high. This is especially the case when transaction costs exceed the net proceeds initially expected by short video users from the authorization, making it impossible to carry out the transaction and leading to infringement. To effectively control the copyright infringement of short videos, it is necessary to build a cross-platform information-sharing mechanism to reduce search costs, establish a unified copyright management platform to reduce coordination costs, and give full attention to the role of technical support to reduce regulatory costs. Digitization and transnational communication networks bring new actors and interests into the sphere of copyright governance, generating new institutional dynamics due to the emergence of new technologies and market opportunities . NotablyThe popularity of the Internet and the rise of digital technologies have transformed former passive recipients of information into active content creators. A thriving participatory culture has increased public participation in creating short videos. According to the 48th statistical report “The Development of China’s Internet Network” released by the China Internet Network Information Center (CNNIC), as of June 2021, the scale of short video users in China has reached 880 million, 87.8% of the total netizens . HoweverIn recent years, copyright governance of short videos has become a hot issue of concern in the academic community . Most stAlthough, in terms of academic theory  and judiConsidering the importance of the copyright governance for short videos and fulfilling the research gap, this study intends to address the research questions, “how copyright governance is working for short videos, and what are the economic consequences of the proliferation of infringing short videos?” To address the research questions, this study intends to explore the economic aspect of copyright governance in relation to the proliferation of infringing short videos.The following is the format of our study. The second section deals with methodology. The third and fourth section provides findings and discussion section, respectively. After providing future study directions, we conclude our study.To familiarize readers with the core theoretical and analytical framework, at first, we present a brief introduction to transaction cost economics. In the third section, we provide a comparative discussion based on transaction cost economics theory. Logical reasons are provided for the application of transactional costs and blockchain technology to start-up finance in the proposed theoretical model. Then, our model is compared to findings and arguments presented in the existing literature. In the fourth section, we provide recommendations to enhance copyright governance based on the study’s findings.Transaction cost theory in economics is considered a theoretical tool with a wide range of uses. Economist Oliver Eaton Williamson  pointed In the 1930s, the economist Market and Hierarchies, transaction cost economics is considered one of the prominent theoretical models in the management and organization discipline , and the existence of asymmetric information, they can only achieve bounded rationality . The secIn the short video market, copyright trading activities are complex . It is dShort video development is still in its infancy in China, although it began in 2011 in the United States (US). However, numerous domestic mobile short video social applications have shown remarkable potential, such as Toutiao’s Douyin and Tencent’s Meipai, as well as Pear Video, Ergeng, and other applications, which all have continually growing user bases. According to CBN Business Data’s “2017 Short Video Industry Big Data Insights,” the number of mobile video users in China reached 525 million in December 2017, with the number of short video industry users continuing to expand, resulting in a new explosion point for mobile video .As previously mentioned, the term “short video” means a video format in which the length of the film is measured in seconds rather than minutes. For quick shooting and editing, it mostly relies on mobile smart terminals, and it may be shared and seamlessly integrated in real time on social media platforms . Short vTake, for example, Douyin, a short video platform with a huge domestic user base and influence: while it uses the user-generated content (UGC) production approach, with users serving as both producers and communicators, it is simple to create and enter. Barriers to entry are minimal, and by using the UGC approach and being both easy to enter and create, Douyin is a great social product. Due to its users, Douyin is more than simply a place to watch and make short films, it is also a place to express yourself and share your life.According to the “2017 China Short Video Industry Research Report,” a large number of mobile short video applications have been intensively launched since 2016, with Tudou transforming into a short video platform in April 2017; Toutiao Video being upgraded to Watermelon Video in June 2017; and second receiving renminbi (RMB) 100 million in financing in August 2017. The competitive pattern of the short video industry’s market has increasingly stabilized, and a steady commercial monetization model has emerged. In general, the short video market is evolving quickly and exhibiting a positive trend, resulting from the combined effect of the external environment and internal driving forces .With regard to the external environment, the widespread availability of mobile smart terminals and the maturation of 4G mobile Internet technology provide critical technical support for short videos, while changes in user-content consumption demand have shifted the overall social environment from a graphics- and text-based era to a video-based era . User-drFurthermore, the rapid development of local short videos has resulted in the formation of a comprehensive production and distribution chain. Content-specific institutions, platform-specific institutions, and other types of institutions produce both content and platforms. Three mainstream media, namely, CCTV, People’s Daily, and Xinhua News Agency, represent content agencies; Toutiao, Tencent, Kuaishou, and Miaopai represent platform agencies. As a new communication style, the fragmented expression of short videos is convenient for producers and enjoyable for spectators. It contributes to the media industry by meeting people’s spiritual and entertainment demands, while giving the content of products and means of expression in news communication a fresh lease of life . HoweverTransaction cost theory is the key to understanding the frequent occurrence of short video copyright infringement. In line with transaction cost economics, transaction costs are believed to be a key factor affecting transactions, with high transaction costs hindering or even preventing the formation of the market. Similarly, in the short video market, the cost of a market transaction is higher than the transaction fee ordered by the court for infringement. The public will choose to abandon licensing negotiations or even ignore the issue of licensing and using the work . From thWith the popularization of mobile intelligent terminal equipment, the simplification of video production technology, and the rise of various short video platforms, such as Vibrato and Kuaishou , the traThe copyright of short videos has a considerable degree of complexity, which is concentrated in two aspects. First, the originality of short videos is ambiguous that directly affects whether the short video can become the object of copyright protection. China’s newly revised Copyright Law has adjusted the definition of “work” and introduced the concept of “audiovisual works” to include new content forms such as short videos in the scope of copyright protection of works . HoweverOpportunism is an important behavioral feature of “economic subjects,” the term that refers to the nature of people in economic activities . EconomiDouyin and Kuaishou. The popularity of short videos is usually short-lived, and strict copyright protections may make it difficult for creators to benefit from the first-mover advantage. This gives copyright owners an economic incentive to encourage the public to distribute and use their works without copyright restrictions . Based on the Copyright Law’s principle of fair use of works, whether such secondary creation short videos constitute infringement needs to be analyzed according to various circumstances . For exaCopyright transactions in the short video market are exchanges on works between rights holders and users. Transaction costs mainly come from search, coordination, and regulatory costs . High trOn completing any transaction behavior, a search process is undertaken between the two parties to the transaction, incurring the resulting search cost, which is the cost necessitated to obtain evidence and exchange information on the transaction object . For proThe seeking of authorization by the users of short videos largely depends on the search costs required to find copyright information. The combined effort of government, industry associations, platforms and creators, and other short video-related stakeholders is needed to build a unified short video audiovisual copyright database that is free and open to the public . This caThe cost of coordination refers to the cost of making copyright trading decisions and executing trading activities. According to China’s Copyright Law, the dissemination and use of copyrighted short video works should follow the principle of “authorizing first, then using,” in addition to complying with the conditions of “fair use” and “statutory permission to use” . In the Moreover, many ordinary individual creators are unlikely to have access to the film party or the publicity team, making it even more challenging to obtain the copyright owner’s authorization . In the via the organization (When copyright owners and users are highly dispersed, establishment of a unified copyright management platform will simplify the purchasing of licenses by introducing a fixed interface. This would reduce the cost of coordination, enabling the market to play a role and helping to promote the legal use of audiovisual works . A more nization . A unifinization .Timely monitoring, discovery, and investigation of infringement comprise the premise of effectively regulating the use of short video copyright and ensuring the smooth progress of short video copyright trading activities. However, this remains challenging to supervise in practice . On the With the rapid development of a new generation of information technology, such as blockchain, cloud computing, big data, and artificial intelligence , the appMany large video platforms in China have also established different degrees and patterns of automated infringement detection systems . The tecWith the rapid development of China’s short video industry, the problem of short video copyright infringement has become increasingly prominent. To some extent, copyright issues have become a stubborn disease affecting the development of the short video industry. Relevant legislative, judicial, and administrative departments are taking several measures to rectify the chaos of short video copyright infringement. For example, since 2018, the rectification of short video copyright has been regarded as the key task of the Sword Network’s special action. China’s newly revised Copyright Law has significantly increased the cost of infringement, as well as increasing the crackdown on infringement by introducing a punitive damages system with higher amounts for infringement damages.Diverse methodologies with different theoretical bases can construct a complete framework for understanding the ordering of the short video industry and the circulation of short videos. Transaction cost economics and its economic and institutional theory variants are popular and informative methods. According to transaction cost economics, the short video piracy problem is simply a market failure caused by excessive transaction costs. The legal copyright transaction in the short video market entails significant transaction expenses. Transaction costs are high, particularly when they exceed the net revenues anticipated by short video consumers from the authorization, rendering the transaction difficult to complete and resulting in infringement. The key to solving the problem of market failure caused by transaction costs lies in reducing transaction costs and making transactions relatively easy, improving the realizability of trading motivation and the possibility of trading.The original contributions presented in the study are included in the article/supplementary material, further inquiries can be directed to the corresponding author.ML designed the research plan, collected the data, analyzed the data, wrote the manuscript, revised the manuscript, checked the final version of the manuscript, and approved it for publication.The author declares that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.


Cognitive Behavioral Therapy is delivered in most of the early intervention services for psychosis in different countries around the world. This approach has been demonstrated to be effective in decreasing or at least delaying the onset of psychosis. However, none of them directly affect the comorbidity of these types of patients that is often the main cause of distress and dysfunctionality. The Unified Protocol for the Transdiagnostic Treatment of Emotional Disorders (UP) is a psychological intervention that combines cognitive-behavioral and third-generation techniques that address emotional dysregulation as an underlying mechanism that these disorders have in common. The application of this intervention could improve the comorbid emotional symptoms of these patients.The study is a randomized controlled trial in which one group receives immediate UP plus standard intervention and the other is placed on a waiting list to receive UP 7 months later, in addition to standard care in one of our early psychosis programs. The sample will be 42 patients with UHR for psychosis with comorbid emotional symptoms. The assessment is performed at baseline, at the end of treatment, and at 3-months’ follow-up, and includes: general psychopathology, anxiety and depression, positive and negative emotions, emotional dysregulation, personality, functionality, quality of life, cognitive distortions, insight, and satisfaction with the UP intervention.This will be the first study of the efficacy, acceptability, and viability of the UP in a sample of young adults with UHR. The results of this study may have clinical implications, contributing to improving the model of care for young people who consult for underlying psychotic, anxiety, and/or depressive symptoms that can lead to high distress and dysfunctionality.https://clinicaltrials.gov/], identifier [NCT04929938].[ In recent decades one of the main topics of research in mental health has been psychotic disorders and, more specifically, their first clinical manifestations. Cumulative research has found evidence highly suggestive of a relationship between the duration of untreated psychosis (DUP) and both short- and long-term prognosis, of a relationship between longer DUP and more severe positive symptoms, and of more severe negative symptoms and lower chance of remission at follow-up . For thiIn this sense, most psychotic disorders do not appear abruptly. Rather, the onset is preceded by subclinical manifestations of symptoms that gradually increase in frequency and intensity . This peThere are recent studies that relate the stigma associated with the diagnosis of UHR with a worse prognosis  and stimFurther, transition to psychosis is not the only outcome for people at UHR . Some stRecently, a growing body of literature has suggested that the classification of mental disorders needs to shift from a categorical model (such as DSM or CIE) to a dimensional one . Under tThe development of a dimensional approach has fostered the creation of different treatment alternatives, such as transdiagnostic models . These mCurrent psychological interventions targeting attenuated psychotic symptoms have proved effective in reducing the rates of transition to psychosis in the medium term  and in rThe UP has shown a reduction in symptoms of anxiety and depression in several mental disorders  with a large effect size, an increase in adaptive emotional regulation strategies paired with a decrease in maladaptive regulation strategies at a moderate effect size, and an increase in functioning and quality of life . FurtherTo date, there is no published study that has used the UP in the treatment of comorbid emotional symptoms in patients that meet UHR criteria, save for a single case study using the UP in a person with treatment-resistant schizophrenia  with proUltra-high risk (for psychosis) patients often have difficulties in engaging with mental health services  being thA pilot study is under way to assess the feasibility and efficacy of group UP to reduce comorbid emotional symptoms in patients that meet UHR criteria. In the context of the SARS-CoV-2 pandemic, the group sessions are being conducted online. Given the evidence cited above, this method of delivering the intervention would be as effective as in-person treatment with the added benefit of encouraging the attendance of people residing in different geographic territories .Given the high level of comorbid anxiety and depression among individuals meeting UHR criteria, the main objective of our study is to evaluate the efficacy of UP in addition to TAU as compared to TAU in targeting symptoms of anxiety and depression in UHR for psychosis patients.As secondary objectives, changes in attenuated symptoms of psychosis, transition to psychosis rates, cognitive distortions, quality of life, metacognition, personality, and psychosocial functioning, and the satisfaction of participants with the treatment, are being assessed. Further, assessment will be made of whether the results are maintained at 3 months’ follow-up. Different clinical trajectories will be analyzed for comparison with previous studies .This study is a randomized controlled trial. All patients are assessed at baseline. Patients are assigned to either treatment group, one receiving immediate treatment with UP and treatment as usual, or to a waiting list, only receiving treatment as usual. All patients are assessed post-treatment and at 3-months’ follow-up. After the final assessment, patients in the waiting list are offered the UP. A list of random numbers created for this purpose is used.Participants are people who meet criteria of UHR for psychosis and who have comorbid symptoms of emotional disorders and are receiving treatment in one of the Early Pychosis Programs (PIPPEP) in Parc Sanitari Sant Joan de Déu.The inclusion criteria are (1) age between 18 and 35 years old, (2) a diagnosis of UHR for psychosis in the last 3 years and inclusion in our early intervention program, (3) symptoms of a comorbid emotional disorder, (4) fluent Spanish or Catalan, and (5) signing the informed consent (IC).The exclusion criteria are (1) a frank psychotic episode in the past or in the present, (2) intellectual disability, (3) an organic disorder that explains current symptomatology.The variables to be studied are evaluated using the instruments described in The evaluation is being carried out at 3 time points. A detailed description of the measures used in each evaluation is reported in Evaluators have been trained in psychological evaluation and specifically in the administration of the CAARMS . They alCAARMS scores are also collected at the time patients begin treatment in our early psychosis program, prior to entering the baseline assessment of the present study. Medication changes and number or TAU sessions will be recorded as a control variables. Types and dosages of medication will be recorded at the three time points of assessment.All study participants receive TAU, within our early intervention program. It includes the following interventions: psychological therapy (about 20–40 sessions of CBT) as well as psychiatric treatment , social work intervention , nursing care , individual cognitive remediation (if necessary), and family therapy. The number of sessions received in TAU depends on the clinical status of each patient. The maximum duration of TAU is 5 years. CBT delivered in TAU consists of techniques such as behavioral experiments, socratic questioning, and some exposure techniques mainly focused on subthreshold psychotic symptoms . PatientFidelity to the UP treatment protocol is guaranteed through weekly supervision with an accredited therapist. In addition, the therapists who will perform the UP intervention have undergone a 20-h training course. The contents of each module are summarized in an infographic and delivered to patients after the UP session to improve adherence to the intervention and acquisition of the techniques.Once the participants are recruited to the study, they are randomized into one of the two conditions: TAU + immediate UP (TAU + imm UP) or TAU + WL (TAU + Waiting List). The first group will receive UP immediately in addition to the TAU. The second group will do the TAU while doing the assessments. During this period these patients act as a control group. Seven months later, these patients will receive UP, in addition to TAU. Assessments will also be made at the same time points. This type of study has been carried out previously . The numAccepting an alpha risk of 0.05 and a beta risk of less than 0.2 in a bilateral contrast, 21 subjects in the PU + TAU group and 21 in the WL + TAU group are needed to detect a difference equal to or greater than 1.57 units. The common standard deviation is assumed to be 1.6. A follow-up loss rate of 20% has been estimated.post hoc analysis will be conducted. Due to the nature of the present study, we expect to identify subgroups of patients presenting differing evolutions in study variables according to the number of sessions they have received.To analyze the improvements in primary and secondary variables throughout the study, linear mixed model analysis will be used. This analysis will allow us to study the main effects of time , treatment condition (TAU vs. TAU + UP), and number of sessions received . We will also calculate interaction effects  which will reveal whether the treatment condition and the number of sessions received interacted with time in the prediction of changes in study outcomes. In the event that we observe a significant interaction, The rate of transition to psychosis of patients in each condition and the CAARMS symptom severity will be calculated in order to evaluate changes in subthreshold psychotic symptoms . We willTo the best of our knowledge, this is the first study to investigate the effectiveness of UP in a sample of young adults diagnosed with UHR who also have comorbid emotional symptoms. If the results of this study show that UP is effective in treating the comorbid symptoms of UHR for psychosis, this finding could contribute to expanding the psychotherapeutic approaches that can be used with young people presenting with an at-risk mental state. UP may be complementary and/or an alternative to standard CBT approaches. This study would need to be replicated with a bigger sample.Unified protocol has been shown to be effective in patients with a primary diagnosis of emotional disorders, including cases with comorbidity, according to the systematic review studies and meta-analyses conducted to date . We hypoThe UP contents and the way each emotion regulation technique is introduced and trained for helps patients to normalize their emotional symptoms or disorders, because all people can experience intense emotions and respond with emotional behaviors. It is positive for all people to improve their emotional regulation skills. This perspective focused on training skills can also help to reduce mental health stigmatization. In addition, UP uses expressions like “emotional experiences,” “intense emotions,” and “emotion driven behaviors” instead of other terms like “aggressive response” or “negative emotions.” All these aspects can help reduce the rejection of treatment by mental health services, especially in young people.The telematic group format of the UP could improve therapeutic adherence in young people, as they are familiar with new technologies . FurtherCognitive behavioral therapy delivered in TAU is an intervention that has already been shown to be effective in patients of this type . HoweverGiven the high comorbidity of emotional disorders in patients with UHR  and the One limitation of the study is the potential difficulty in isolating the impact of UP on outcome measures. This study is a naturalistic study, that is, it is carried out in the context of public mental health, which is why it is comparable with what has been done up to now. Clinically, it would be more ethical to offer an intervention like UP to all the participants of the study. We expect that the statistical analyses mentioned above can increase the robustness of the study results and solve this limitation.The UP has already been shown to be effective with similar symptoms  and thisThis study has been evaluated and approved by the Drug Research Ethics Committee (CEIm) of the Parc Sanitari Sant Joan de Déu. All participants are being provided with an information sheet explaining the objectives and procedure of the study as well as the confidentiality of the data collected. All participants are being asked in writing for their consent in accordance with the Declaration of Helsinki  and Law TP was the principal investigator of the project, led the development of the manuscript, and investigator in charge of recruiting patients. TP, JO, SO, RL-C, and MF-Q did the study design and decided upon all the outcome measures. MF-Q was carrying out the evaluation process and configured the data collection system. RL-C and TP were carrying out the therapy of the UP and made the infographics of each module. JO was supervising all the therapy process and content of the infographics. SO was responsible for determining sample size and power calculation and proposing all the statistical analyses. RL-C and MF-Q kept the patients linked to the study. JO and SO supervised the development of the study. All authors contributed to the manuscript and approved the final version of the manuscript.


Renal transplantation is the treatment of choice for patients suffering from chronic renal disease, one of the leading causes of death worldwide. Among the biological barriers that may increase the risk of acute renal graft rejection is the presence of human leukocyte antigen (HLA) incompatibilities between donor and recipient. This work presents a comparative study of the influence of HLA incompatibilities on renal transplantation survival in the Andalusian (South of Spain) and United States (US) population. The main objective is to analyse the extent to which results about the influence of different factors on renal graft survival can be generalised to different populations. The Kaplan–Meier estimator and the Cox model have been used to identify and quantify the impact on the survival probability of HLA incompatibilities, both in isolation and in conjunction with other factors associated with the donor and recipient. According to the results obtained, HLA incompatibilities considered in isolation have negligible impact on renal survival in the Andalusian population and a moderate impact in the US population. Grouping by HLA score presents some similarities for both populations, while the sum of all HLA scores (aHLA) only has an impact on the US population. Finally, the graft survival probability of the two populations differs when aHLA is considered in conjunction with blood type. The results suggest that the disparities in the renal graft survival probability between the two populations under study are due not only to biological and transplantation-associated factors, but also to social–health factors and ethnic heterogeneity between populations. Transplantation is the most appropriate treatment for end-stage renal disease, one of the deadliest diseases in the world. The low availability of organs for transplantation has led to long waiting lists and transplant tourism in some countries. In Europe and the United States (US), legislative, regulatory and humanitarian services are provided to expedite the transplantation process and the appropriate choice between donor and recipient . HoweverThe process of admission, surgery, and post-transplant treatment differs between the US and most European countries. In 2019, 60% of transplant recipients in the US had public coverage under the federal Medicare program, while 32% were covered by private insurance , making Once patients have been added to the waiting list, access to transplantation is determined by the renal allocation scheme. Countries such as the United Kingdom, France and Spain have developed their own national allocation algorithms, while other countries such as Austria, Belgium, Croatia, Germany, Hungary, Luxembourg, the Netherlands and Slovenia are involved in international organ exchange initiatives such as Eurotransplant and Scandiatransplant . In SpaiThere are two HLA molecules : class IStudies of this nature have been characterised by the independent analysis of HLA incompatibility and blood group, and to the best of the authors’ knowledge, there is no study that combines them or that analyses the effects of the sum of HLA incompatibilities (aHLA) considering two very different population databases. In this sense, the aim of this work is to analyse the effect of HLA on the probability of renal survival in the American and Andalusian populations, while considering the different HLA-A, HLA-B and HLA-DR incompatibilities in isolation and, subsequently, jointly in different time horizons and together with other factors such as blood group. The work attempts to discuss some of the possible causes of the differences in behaviour between the two populations and the difficulties involved in the analysis of two such heterogeneous populations. In a previous paper , the autThe paper is structured as follows: the methodology followed in this study is briefly described in Bibliographic search of survival analysis studies that consider blood group and HLA incompatibilities as factors that have an impact on renal transplant survival.Pre-processing of the available databases by performing cleaning and quality improvement process, including standardisation of date-type variables, identification of null values, elimination of unimportant variables, renaming of some variables in order to better describe their content, standardisation of values using the scaling technique and conversion of categorical variables.Analysis of renal graft survival using the Kaplan–Meier estimator considering the different HLA incompatibilities, both in isolation and together as well as in combination with the blood group.Obtaining the coefficients of the Cox model for each of the identified factors with greater significance identified in the previous step.Graphical representation of the survival probabilities obtained and discussion of the results.In order to carry out this study, the general methodology for survival analysis was followed:The renal transplant data that have been analysed in this work come from the Autonomous Transplant Database of Andalusia (SICATA), while the US data have been provided by the United Network for Organ Sharing (UNOS). For both databases, single renal transplants from cadaveric donors between 2006 and 2019 (both inclusive) were selected. The Regional Transplant Coordination Agency in Andalusia started database compilation for renal transplantation in 2006. No data are available for previous years. On the other hand, there has been a continued improvement in long-term success of renal transplantation in the last 10–15 years. Therefore, the situation before 2006 is not significant in light of today’s procedures. Likewise, both databases have been designed to cover the same time interval in order to ensure the greatest possible homogenization between them. Transplants from later dates have been discarded to avoid the possible influence of the COVID-19 pandemic on graft survival probability.The number of transplants for SICATA is 3478, while for UNOS, there are 112,877 transplants. The number of transplant centres for SICATA is 6, while for UNOS, it is 270. The centres with the highest number of patients in SICATA are Virgen del Rocío Hospital (Seville) with 974 transplants, Puerta del Mar Hospital (Cadiz) with 765 transplants and Virgen de las Nieves Hospital (Granada) with 676 transplants. In UNOS, the names of the centres are encrypted. The centre with the highest number of operations reaches 2208 transplants. On the other hand, the average number of days on the waiting list for SICATA is 2.6 years, while for UNOS, it is 3.6 years .The data refer to single renal transplants from donors older than 3 years and recipients older than 18 years, considering only donors and recipients with the same blood type. In SICATA, there is an equal distribution between these two groups, both for donors and recipients, whereas in UNOS, there is a predominance of group 0. This characteristic does not correspond to the distribution of blood groups in the Spanish and American populations, which have a similar distribution. Another notable dissimilarity between the two populations is in the age of donor, where there is a difference of approximately 14 years.HLA typing from the SICATA database is based on DNA-based methods, specifically RFLP-PCR (restriction fragment length polymorphism polymerase chain reaction) and matching at the antigen level. The serological tests for HLA typing and anti-HLA antibodies are performed before transplantation. Finally, the Regional Transplant Coordination Agency notes that there is excellent monitoring of vital status and type of renal replacement therapy, but they compile no data about post-transplant complications. With regard to the UNOS database, in 2011, the OPTN mandated DNA-based HLA typing methods for deceased donors . TypicalWith respect to the levels of HLA incompatibilities , the differences in the probability of survival for UNOS and SICATA are not very relevant considering the different values in isolation. Survival analysis for aHLA (HLA-A + HLA-B + HLA-DR), with values between 0 and 6, which offers differences in behaviour as pointed out by some authors ,18. FiguThe 10-year survival probability for UNOS (a) and SICATA (b) considering aHLA is presented in The renal survival probability at one, three and five years considering the different aHLA combinations for UNOS and SICATA is shown in Combining multiple factors to make population groupings can reveal significant differences that are not obtained by individual factor analysis. In SICATA, blood type has virtually no relevance for survival probability a, nor dop > 0.05). The error bars are the 95% confidence intervals for each value of the hazard ratio, omitted for SICATA given the magnitude of these.Finally, Logistic and structural factors between the two populations can impact the survival probability curve, including the omission of HLA-B in the US allocation and the changes derived from the introduction in 2014 of the new kidney allocation system (KAS) in the US , which aIn the US, the improvement in survival probability  has beenWith respect to the levels of HLA incompatibilities, the most notable differences between values are reached in the HLA-DR mismatch for UNOS. HLA-DR mismatches in particular were significantly associated with worse renal graft survival in the US . The treIn the aHLA survival analysis, it is well established in the literature that, in deceased donor renal transplants, zero or one aHLA mismatch offers a significant benefit in graft survival with respect to transplants with a higher number of mismatches . HoweverThese behavioural differences in the impact of aHLA on renal survival between UNOS and SICATA may be due to ethnical factors. SICATA does not collect data in this regard, as it is understood that this factor is not very significant given the majority of Caucasians in Spain. In the UNOS database, this factor is included for both donor and recipient, with a predominance of Caucasians, although with greater ethnic heterogeneity than in Spain. Some studies conclude that the best HLA matches occur when the donor and recipient are of the same race when the transplant comes from a cadaveric donor . In addiThis paper has presented the analysis of the influence of HLA incompatibilities on renal graft survival in the American population (UNOS database) and in the Spanish region of Andalusia (SICATA database). The study included a Kaplan–Meier analysis for each incompatibility in isolation , together, with combinations of values and in combination with the blood group. A study based on the Cox regression method quantified the influence of the different HLA incompatibilities in relation to other factors that are generally included in other studies.p < 0.005), while for SICATA, it was HLA-B, although not significantly (p = 0.1).The results indicate that each increase in HLA incompatibility was significantly associated with a higher probability of graft failure in UNOS, while no relevant differences were observed in SICATA. These behaviours may be due to the ethnic diversity between the two populations that have been analysed. Cox regression modelling revealed that HLA-DR incompatibility was the most important factor in renal graft survival for UNOS (p < 0.005) taking aHLA scores of three or lower in combination with blood group revealed that the analysis of some factors has no relevance for renal survival when analysed in isolation but may have significance when combined with other factors. The work highlights the need for exploratory algorithms that combine multiple factors to find possible behaviours of interest that are hidden with an individual analysis. The creation of a multi-parametric algorithm could offer a better hypothetical prognosis for renal transplantation.The work shows that the discrepancies between the different databases are not only due to biological factors. In this sense, the conclusions obtained for each database in isolation cannot be generalized to the other due to cultural, religious, socio-political, ethnic and/or nutritional differences between the two populations that have been the subject of this study. Other clinical factors that could also be have an effect include the time on dialysis prior to transplant, the proportion of high immunological risk transplants considering highly sensitized patients undergoing retransplantation, and cold ischemia time, which should be significantly longer in the US than in Spain due to the long distance travelled for organs. In addition, the high statistical significance in SICATA (


Objectives: Extant research on cost-sharing finds no impact on health care utilization when the amount is insubstantial. This research investigates the effects on nonacute outpatient services for schoolchildren with refractive errors in Taiwan and discusses the potential harm caused by cost sharing and relevant cost containment policies. Methods: Longitudinal claims data from the National Health Insurance database are employed. District demographic information is also used for aggregate-level analyses. Interventional modeling is conducted on pooled individual-level data with a Poisson model and negative binomial models. Generalized least square modeling is performed on aggregate district-level data to elucidate the impacts of cost sharing and the reimbursement rate with controls for patient and institutional characteristics, district socioeconomic factors, and competitiveness among institutions. Results: The findings of this study show that cost sharing does not significantly affect children’s utilization of outpatient services in the patient-level analyses. However, it significantly decreases the service volume based on the results of district aggregate analyses. There are potentially marginal patients in society, and they are more likely to be girls in poorer families, whose chances of seeking medical care significantly decrease when cost sharing increases. Conclusions: The gap in health inequity can be widened when stringent cost-containment policies are implemented. The offset effect caused by delayed care may also result in higher health care expenditures later. Cost sharing for children should be separately and prudently designed to better protect them from deprivations caused by changes in health policies. The notion that an increase in cost sharing can reduce the usage of health care services has been well established since RAND cooperation conducted its health insurance experiment (HIE) in the 1970s  . Global However, studies on cost sharing based on Taiwanese data suggest that user fees are unlikely to change patients’ care-seeking behavior, meaning that patients are insensitive to price changes ,9. ThoseRefractive errors are common vision problems around the world. Myopia, in particular, may be a simple, minor condition for many people. However, for many others with serious eye disorders such as cataracts, glaucoma, or maculopathy, myopia is the root of diseases that can lead to blindness ,16,17. IThe high prevalence of myopia among schoolchildren in Taiwan has drawn public health authorities’ attention. Continuous efforts to prevent myopia have always been an important public policy for both the Ministry of Education (MOE) and the Ministry of Health and Welfare (MOHW) of Taiwan. Approximately 30 years ago, the MOE initiated the Taiwan Student Vision Care Program (TSVCP) to fight myopia. Nationwide student vision screenings were performed by school nurses on a regular semester basis. If students failed to meet the 20/25 threshold , they receive a follow-up eye examination slip that has to be signed by an ophthalmologist and returned to school nurses  , dental care, traditional Chinese medicine, and renal dialysis. Under each of the common global budgets, physicians maximize their share by expanding their volume of services, in a zero-sum game . The NHICopayment, which is set by the NHIA, is charged alongside registration fees by health care providers when patients receive outpatient consultation services. Registration fees vary across individual providers and usually range from TWD 20 to TWD 300, depending on the pricing policies of each facility, which is related to the geographic location and level of facilities. Meanwhile, copayment is tiered and regulated by NHIA to steer patients toward seeking services from local clinics and district hospitals in lieu of medical centers or regional hospitals where tertiary and secondary care are provided. There have been several copayment policy reforms in the past 20 years, including copayment changes for inpatient services, ambulatory care, referral outpatient services, nonreferral outpatient services, prescription medication services, lab test services as well as high-user surcharges for outpatient services . A detailed description of the copayment adjustments is provided in This study adopts a broad definition of cost sharing, including copayment, registration fee, and insurance premium. The extant research rarely discusses the impact of premium adjustment because it is considered a sunk cost and not relevant to the decision making of patients. However, in Taiwan, the premium is a type of payroll tax, and the premium rate (fee rate) is floating to let NHIA maintain a balanced budget. Higher NHI expenditures imply higher rates in the future. As a result, an upward adjustment in the premium rate may signal to the insured that they to conserve the utilization of health care.Under the GB umbrella of Taiwan’s National Health Insurance (NHI) system, incentives for physicians are dynamically subject to the total volume of services provided in different regions and different classes of health care institutions. The revenue sources for Taiwan’s providers are threefold: NHI reimbursement, copays and registration fees from patients, and self-pay services and products .With the budget capped and fee-for-services as the predominant payment scheme, there is fierce competition among health care providers for patients, and thus, return visits are important. Except for the copayment and registration fee for each visit, there is no out-of-pocket cost for insured patients who receive services in the care categories approved by the administration of NHI. An ophthalmologist’s monthly revenue, therefore, is primarily dependent on the total number of service points in a month and the dollar value of each point in the region in which the provider is located. The dollar value of each service point is recalculated each quarter based on the region’s total points claimed during that period. Restricted by the predetermined expenditure cap, a region that has a higher service volume has a lower dollar value per service point and vice versa. Thus, reimbursement rates for consultation services are floating and differ across regions depending on the allocated budget, the number of services provided, and the practice patterns of physicians in a region. Physicians’ practice is guided accordingly when incentives change. The research focus here is threefold: the extent to which service volumes for nonacute conditions are affected by the point values of GB reimbursement, the changes in cost sharing, and the competitiveness among providers within a locality.The data in this study are from the NHI database as documented and released by the MOHW, which provides claims data and provider and patient background information. Since the NHI covers over 99.5% of legal residents in Taiwan, it is the most representative health care database available for the country. Two million randomly sampled beneficiaries were drawn from the entire population of Taiwan in 2010. Their claim information is traced back to 2000 and forward to 2017 to form the longitudinal structure. In this study, we only use data up to 2015 before the International Classification of Diseases code switched from the ninth version to the tenth. The primary diagnoses for each outpatient visit in the NHI database are assigned a code based on the ICD-9 code. This study focuses on schoolchildren with refractive problems, predominantly myopia (ICD code 367.1). Also included are astigmatism (367.2) and amblyopia (368.0). The various forms of utilizing outpatient services are the outcome measure; however, the services are not exclusive to ophthalmologist office visits; thus, the observed service volumes increase to include more comprehensive results for the patients’ general health conditions). Since the point values float every quarter, the observation frequency is quarterly in the study. In addition to individual patients as the observed units, data are also stratified by the health care provider and geographic location for analysis.Patients who are less healthy tend to pay more than healthier people for physician visits. Thus, each patient’s health status has an impact on the utilization of health care services. To establish an objective measure of each patient’s health condition, the Charlson comorbidity index (CCI) is adopted to capture patient comorbidity. The CCI is a method of categorizing patient comorbidities based on ICD diagnosis codes. Each comorbidity category has an associated weight (from 1 to 6), and the sum of all the weights results in a single comorbidity score for a patient. A score of zero indicates no comorbidities. The higher the score is, the more likely the predicted outcomes of mortality or higher resource use. Over time, there have been changes to the index presented in different studies. The original index was developed with 19 categories , but it Health care utilization can be affected by providers’ attitudes. In particular, competitiveness among providers may be related to the strategies of institutions; for example, physicians may seek to manipulate the frequency of patient follow-up visits, resulting in a so-called supplier-induced demand (SID). The Herfindahl-Hirschman index (HHI) is a commonly accepted measure of market concentration. It is calculated by squaring the market share of each firm competing in a market and then summing the resulting numbers. It can range from close to zero to 10,000. The closer a market is to being a monopoly, the higher the market concentration (and the lower the level of competition). In the market for myopia care, market share is calculated by outpatient/physician office visits within the year in each zip code defined by the NHIA. A similar method has been employed previously in contexts where there is no published HHI available for specific health care services .Our empirical analyses are twofold. First, individual-level analyses are conducted with patients as the observation unit and facilities as the observation unit, and second, district (cities/counties) aggregate-level analyses are conducted for patient utilization and facility services provided.Quarterly count data for physician office visits are obtained for children with refractive errors in our sample. The data are counted at two different levels, patient and institution . At the patient level, the panel regression method is not suitable since each patient does not always have annual office visits throughout the entire 16-year study period. As a result, each period is composed of a large number of very different patient groups. For this reason, we use the pooled data method instead of the panel regression method.In addition to the ordinary least squares (OLS) method, the Poisson model and negative binomial (NB) regression are also employed. OLS assumes that the variation in the dependent variable at each level of the regressor is the same; however, this is usually not the case for count data. Poisson regression, on the other hand, allows the responses at each level of the regressor to become more variable with increasing means. The Poisson model is subject to the highly restrictive assumption that the variance is equal to the mean given by the model. Based on the Poisson-gamma mixture distribution, NB is popular because it models Poisson heterogeneity with a gamma distribution .Following the analysis model of Chandra et at. (2010) , the quaUTIL is a measure of utilization  per patient p at time t in district i, Point is the reimbursement value after the implementation of GB, and p in district i. The Xs are patient background variables such as gender, age, parent income level, parent job classification, and CCI, that is, patients’ comorbidity condition in that quarter. Time captures changes in general social norms and health and economic conditions. The regression coefficient is denoted by β, and ptε is i.i.d. with normal properties, i.e., The effect of the policy change is identified by β1, which measures the change in the utilization relative to the change in the reimbursement value within provider classifications, and β2, which measures the change in cost sharing of the patients. In Taiwan, patients can freely choose their physicians and health care providers. Although patients may seek services across regions, their behaviors are assumed to be most relevant to their residential location. Thus, the Point and HHI used in the analyses are based on the patients’ location, not the providers from whom they obtain services. Copay is charged differently for different categories of providers, and this amount is averaged out from the quarterly visits of the patients.The patient is the unit of analysis. In the second model, the institution (provider) is the unit of analysis. The counts of refractive error outpatient services provided by each institution serve as the outcome variable (Service):ftX) of facility f in district i at time t include the institution level , institution age, gender of the facility CEO, and institution scale, as measured by the facility’s total outpatient services, total number of physicians, total number of full-time ophthalmologists, and total number of part-time ophthalmologists. The institution characteristics  for patients living in district i at time t, point is the point value for reimbursement with the implementation of GB, and NHCC, which is the number of health care facilities in the district, reflects competitiveness among providers in district i, and Xs are the district socioeconomic and demographic background variables such as the average household income level in the district, population density, number of health care providers, and educational background of residents. Time represents the time trend, which captures changes in general social norms and health and economic conditions. The regression coefficients are denoted by β, and ptε is i.i.d. with normal properties, i.e., outpatient services can be aggregated based on the volume provided by institutions in each district. The estimated measure becomes:fitServ is the total number of services  provided by institutions located in district i at time t. The control variable Xs are the same socioeconomic and demographic variables as described in Equation (3).The aggregate amounts of outpatient services received by patients and provided by institutions are further calculated on the basis of 20 districts (cities/counties) in Taiwan, as presented in Equations (3) and (4), respectively. The results are then submitted for GLS analyses to clarify the extent to which variations in the amounts of outpatient services are determined by health policies such as the copayment and insurance From the NHI outpatient service claim dataset, we retrieve the information for children under 18 years of age from 2000 through 2015. The summary statistics for these children and for the vision care facilities over the whole sample period and in selected years are presented in To obtain a general picture of the utilization of children’s outpatient services, the outcome variables are drawn against time and policy changes, as shown in Regression analyses for patient-level data, as in Equation (1), are presented in To understand the geographic variation in health service utilization, the aforementioned outcomes measured are aggregated to the district level and then analyzed in relation to district socioeconomic and demographic characteristics, with controls for the population density and the density of health care institutions in each district. The results are presented in To ensure the robustness of the estimation, all regressions have been tested by various functional forms by adding and dropping different variables in the regressions. Polynomial forms or log linear forms of the functions are tested based on past econometric experiences. The income, population density, population ratio with a college degree, and institution density are highly correlated, which might cause some concerns about collinearity problems. However, the results do not change significantly when excluding one or some of the variables from the regressions. The details and process are not reported to conserve space.To ascertain the robustness of our results, we also collect the expenditure data on the outpatient services from the patients’ perspective and the corresponding revenue from the institutions’ perspective. The analyses are reported in Since the Taiwanese government started annual vision checkups for all children on school campuses in 1999, parents have grown accustomed to seeking follow-up eye examinations from ophthalmologists in health care institutions if their children do not meet the 20/25 threshold. With the effectiveness of atropine reported by Shih (1999), parents have an incentive to routinely take their children back to ophthalmologist offices to receive the prescription drug. The treatment of myopia addresses a chronic condition, and the aim is to slow down the progression. This nonurgent health care service provides a scenario for understanding the medical-care-seeking behavior of patients and practice pattern of physicians under different fee policies.Based on NHI claim data from 2000 to 2015 for two million randomly selected residents of Taiwan, our results show that the participating health care facilities become younger and provide smaller volumes of services on average over time . The result shows a greater effect than that found in the existing literature , where sComparing the results between the services of clinics and hospitals, the former are more susceptible to district characteristics and policies changes. Hospitals are insensitive to changes in copayments, premium rates, and point values under the GB system. On the other hand, clinics’ volumes of services provided are negatively related to the point value, and their revenues are positively associated with copayments at the district aggregate level, indicating that clinics are more responsive to policy changes. The negative HHI coefficients suggest that health institutions with greater market power tend to provide fewer outpatient services. Competitiveness among health care institutions is directly linked with a greater volume of services, implying the existence of SID for medical services.Finally, income has a positive effect on the outpatient service utilization in patient-level analyses, implying that patients from disadvantaged families tend to under-utilize health care services. The phenomenon of marginal patients could be prevailing. Also suggested is that the parents of the disadvantaged families might seek follow-up services for their children from optometrists in optical shops where walk-in service is possible without a medical fee. Even though the signatures of optometrists on follow-up slips are normally not accepted by TSVCP, the regulations are not strictly enforced because doing so would impose extra burdens on school nurses. In district-level analyses, the effect of income turns negative. The explanations for this phenomenon can be twofold. First, it could be that people who live in wealthier districts tend to be healthier and demand fewer health care services. Another possible explanation is that people in wealthier district utilize somewhat different vision care services than traditional mydriatic eyedrop treatments. For example, vision correction surgery (LASIK) and orthokeratology contact lenses are gaining increasing popularity in Taiwan for containing myopia progression. Both are not covered by Taiwan NHI and, hence, are not recorded in the NHI database. Even though patients who have undergone refractive surgery or orthokeratology still need to be followed up closely for the risk of posterior segment alterations, those patients often receive eye care from the same ophthalmologists who opt out of NHI. Hence, they would show few or no follow-up outpatient visits.There are limitations to this study. First, the percentage of schoolchildren who seek vision care services through NHI is only approximately 30% in our sample, which is far lower than that reported by the Taiwan Health Promotion Administration , accordiThe notion that an increase in cost sharing reduces the usage of health care services has been well established since RAND conducted its HIE in the 1970s . Past stFor the effect on the practicing behavior of providers, competition is the key factor in determining their volumes of services. The HHI has a significantly negative impact, i.e., greater competition induces greater volume of services provided. However, when decomposing the effect to the hospital and clinic levels, only the latter shows a conspicuous effect, indicating that clinics are more susceptible to policy changes and possibly more incentive driven than hospitals.In conclusion, this study provides implications for the relevant authorities regarding the effect of cost sharing on patients’ utilization of care for nonacute chronic conditions. While the fee adjustments may not be substantial and individual patients may not change their care-seeking behavior, the effects at the aggregate level can be significant, considering that more patients do not seek services at all. The cost savings in the short run might thus generate higher medical spending in the long run. In addition, treatments for different diseases have different values, and common forms of cost sharing built into the insurance plans may not align socially optimal outcomes with privately optimal ones . Thus, c