Optimal shelflisting invites profit maximization to become sensitive to the ways in which purchasing decisions are order-dependent. We study the computational complexity of the corresponding product arrangement problem when consumers are either rational maximizers, use a satisficing procedure, or apply successive choice. The complexity results we report are shown to crucially depend on the size of the top cycle in consumers’ preferences over products and on the direction in which alternatives on the shelf are encountered.

ObjectiveThe large-scale epidemic of Coronavirus Disease 2019 has triggered unprecedented physical and psychological stress on health professionals. This study aimed to investigate the prevalence and risk factors of burnout syndrome, and the relationship between burnout and depressive symptoms among frontline medical staff during the COVID-19 epidemic in China.MethodsA total of 606 frontline medical staff were recruited from 133 cities in China using a cross-sectional survey. The Maslach Burnout Inventory was used to assess the level of burnout. Depressive symptoms were assessed (...) by the Patient Health Questionnaire Depression.ResultsDuring the COVID-19 pandemic, 36.5% of the medical staff experienced burnout. Personal and work-related factors were independently associated with burnout, including age, family income, having physical diseases, daily working hours, and profession of nurse. The correlation coefficients between the scores of each burnout subscale and the scores of depressive symptoms were 0.57 for emotional exhaustion, 0.37 for cynicism, and −0.41 for professional efficacy.ConclusionsOur findings suggest that the prevalence rate of burnout is extremely high among medical staff during the COVID-19 pandemic, which is associated with other psychological disorders, such as depression. Psychological intervention for medical staff is urgently needed. Young and less experienced medical staff, especially nurses, should receive more attention when providing psychological assistance. (shrink)

Background: Previous systematic review indicated the prevalence of prenatal anxiety as 14–54%. Pregnant women are a high-risk population for COVID-19. However, the prevalence of anxiety symptoms and related factors is unknown in Chinese pregnant women during COVID-19 outbreak.Objective: To investigate the prevalence of anxiety symptoms and the related factors in Chinese pregnant women who were attending crisis intervention during the COVID-19 pandemic.Methods: The data of this cross-sectional study were collected in about 2 months. Data analysis was performed from April to (...) May 2020. Participants completed a set of questionnaires via the Wechat Mini-program before starting the online self-help crisis intervention for COVID-19 epidemic. A total of 2,120 Chinese pregnant women who were attending a self-help crisis intervention participated in this study. A survey was developed to address possible stress-related factors in pregnant women during the COVID-19 outbreak, including demographic, socioeconomic, and pregnancy-related factors, as well as COVID-19 related factors. Generalized Anxiety Disorder-7 scale and the 10-item perceived stress scale were, respectively, employed to measure anxiety and stress-related factors.Results: A total of 21.7% of pregnant women reported at least mild anxiety, and only 82 women reported moderate to severe anxiety. Factors associated with at least mild anxiety included living in Hubei province, nobody providing everyday life support, pelvic pain or vaginal bleeding, and higher perceived stress. Having relatives or neighbors with a diagnosis of COVID-19 was not associated with anxiety.Conclusions and Relevance: Our findings indicate that evaluation and intervention for maternal and infant health are necessary in pregnant women with anxiety during COVID-19 epidemic, especially those with higher perceived stress, less everyday life support, or vaginal bleeding. Interactions among these related medical, social and psychological factors need to be investigated in future studies. (shrink)

Understanding the role of teachers’ facial expressions in students’ learning is helpful to improve online teaching. Therefore, this study explored the effects of teacher’s facial expressions on students’ learning through analyzing three groups of video lectures. Participants were 78 students enrolled in three groups: one with an enhanced-expression teacher, one with a conventional-expression teacher, and one with the teacher’s audio only. ANOVA was used to explore whether video lectures instructed by the enhanced-expression teacher were better than those instructed by the (...) conventional-expression teacher and the audio-only teacher for facilitating students’ learning, and what is the role of the teacher’s emotions in students’ perceived social presence, arousal level, cognitive load, and learning. The results showed that the video lecture by the enhanced-expression teacher was better than those with the conventional-expression teacher and with the audio-only for facilitating students’ social presence, arousal level, and long-term learning. Interestingly, it was found that the teacher’s emotions could relieve students’ cognitive load. These results explained the inconsistency of existing studies by exploring the mechanism of teachers’ emotions in students’ learning. It also provides teachers with practical guidance for video lecture design. (shrink)

For synchronization of a class of chaotic systems in the presence of nonvanishing uncertainties, a novel time-varying gain observer-based sliding mode control is proposed. First, a novel time-varying gain disturbance observer is developed to estimate the uncertainties. Then, by using the output of TVGDO to modify sliding mode control, a new TVGDO-based SMC scheme is developed. Although the observation and control precision of conventional fixed gain disturbance observer-based control for chaotic systems can be guaranteed by a high observer gain, the (...) undesirable spike problem may be caused by the high gain if the initial values of estimate and true states are not equal. The most attractive feature of this work is that the newly proposed TVGDO can eliminate the spike problem by developing a time-varying gain scheme. Finally, the effectiveness of the proposed method is demonstrated by the numerical simulation. (shrink)

This paper proposes a novel robust fixed-time control for the robot manipulator system with uncertainties. Based on the uniform robust exact differentiator algorithm, a robust control term is constructed. Then, a robust fixed-time inverse dynamics control is proposed. For the proposed control method, the fixed-time stability of a closed-loop system with uncertainties is strictly proved. The newly proposed method exhibits the following two attractive features. First, the proposed control scheme extends the existing fixed-time IDC for the robot manipulator system to (...) the robust control scheme. Second, the proposed method is strictly nonsingular rather than the commonly used approximate approach. Simulation result demonstrates the effectiveness of the proposed control scheme. (shrink)

Recently, scholars have begun to shift focus toward the effectiveness of different teaching methods for entrepreneurship education. However, the establishment of a unified and clear standard for the division of entrepreneurship educational methods remains unfulfilled, affecting the accuracy of research conclusions. In the present study, for the first time, the aim was to divide the entrepreneurship educational method into the classroom teaching method and the extracurricular activity method from the perspective of competency level training. On the basis of the modified (...) planning behavior theory, the influence of entrepreneurship education on entrepreneurial intention was explored. In the present study, 514 college students of 14 universities in China were surveyed. The results reveal that the CTM and EAM had a direct positive bearing on EI, with indirect impact exerted by attitude toward entrepreneurship and perceived behavioral control. Although the direct effects of the two teaching methods were similar, EAM could effectively improve ATE and PBC, thereby resulting in a positive effect on EI to a greater extent. Further observations were made that the participation of research University students in CTM was significantly lower than that of applied University students, leading to lower EI. Additionally, higher EI could be attributed to the more active participation in EAM of male students than female students, while no significant difference was indicated between different majors in EI. The results are of significant reference value for promoting the reform of entrepreneurship education and improving the quality of entrepreneurship education in colleges and universities. (shrink)

An incline S is a commutative semiring where r+1=1 for any r \in S . We note that the ideal lattice of an S-semimodule is naturally an S-semimodule and so is its congruence lattice when S is transitive. We prove that the categories of complete S-semimodules, together with dual functor, internal hom and tensor product, is a ⋆-autonomous category. We define the locally and globally maximal congruences which are related to Birkhoff subdirect product decomposition. We show that the categories of (...) S-semimodules, algebraic S-semimodules and topological S-semimodules are equivalent. Finally, we get a sheaf representation of any S-semimodule. (shrink)

Evidence suggests that participation in plaza dancing may affect mental health. This study for the first time quantified the relationships between plaza dancing and psychological well-being and ill-being. We systematically searched PubMed, Web of Science, CNKI, Wanfang, and VIP to identify relevant studies published from the databases since their inception to July 25, 2021. The standardized mean differences of pre-to-post intervention data were calculated in the meta-analysis. Subgroup and meta-regression analyses were performed to test the potential moderating effects of age, (...) outcome classification, measurement instruments, district, publication year, total sample size, and the duration, frequency, and length of the square dance intervention. A total of 25 original articles met all the eligibility criteria and were included in the review, and 17 studies were included in the meta-analysis. The meta-analysis revealed that plaza dancing improved psychological well-being and reduced psychological ill-being. The study participants’ age and district did not seem to affect the effectiveness of the plaza dancing intervention. The duration and frequency of plaza dancing affected the association between square dance and psychological well-being and psychological ill-being. Plaza dancing has a significant positive effect on psychological well-being and psychological ill-being, and the effects are moderated by intervention modality. Generalizing plaza dancing interventions to promote psychological well-being and prevent or treat psychological ill-being is needed.Systematic Review Registration[www.crd.york.ac.uk/prospero], identifier [CRD42021272016]. (shrink)

Many scholars have investigated education management. Scholars in the education field have made significant achievements in contributing to multiple educational reform policies, while other scholars discuss teacher-related issues from the perspective of organizational behavior. The teaching innovation of high school teachers plays a critical role in students’ learning attitude and motivation, especially in the context of the COVID-19 pandemic. Teachers need to utilize more diversified teaching methods to enable students to carry out effective learning. In order to examine teachers’ teaching (...) innovation, this study explores teaching innovation intentions and performance from the perspective of individual and social factors in combination with goal-oriented behavior and social identity theory. This study conducts questionnaires with a sample of Chinese coastal high school teachers, and obtains a total of 475 responses. The research results show that innovation attitude, positive anticipated emotion, group norms and social identity positively affect teachers’ teaching innovation intention; furthermore, teachers’ teaching innovation intention also positively affects their teaching innovation performance. Based on the comprehensive research findings, this research proposes corresponding theoretical and practical implications. (shrink)

This study explored the correlation between mental toughness and physical activity, and the moderation role between PA intention and subsequent behavior among college students and wage earners. Five hundred ninety-one college students aged from 19 to 24 and 285 wage earners aged from 27 to 58 recruited from seven colleges and five cities in China. A Theory of Planned Behavior questionnaire, MT Inventory, and the International PA Questionnaire was completed online. Results showed that attitudes, subjective norms, and perceived behavioral control (...) explained 46.5 and 38.3% variance in PA intention among college students and wage earners separately. Intention predicted PA behavior significantly among college students and wage earners. Structural equation modeling indicated that the TPB model and the moderation model have an adequate to good fit except the TPB model among wage earners. MT was positively correlated with PA among college students and wage earners and had a significant moderation role in intention-behavior gap among college students and partially affected the transfer of PA intention to behavior among college students. Individuals with high MT had high levels of PA regardless of intention, while PA of those with low MT was low and unstable. Future research should further explore the correlation between intention and PA and the moderation role of MT in different populations using a longitudinal study in order to better understand the correlation between intention and PA, and the transition from intention to PA and better guidance PA intervention to promote PA. (shrink)

The pressure control for a liquid nature gas ship is vital for the cargo handling system which is a nonlinear, unstable, and controllable complex system accompanied by the dynamics of time delay. To improve the control effect, this article proposed a robust controller based on closed-loop gain shaping algorithm by mirror-mapping approach. In addition, the complete mechanism models for the system are established to predict the changes of temperature, pressure, and liquid inventory in the cargo tank. The heat exchanges and (...) evaporation of liquid are also considered. By collecting the data from the LNG ship “Dapeng,” the system models are validated. At the same time, the comparative experiment is introduced to verify the reliability and effectiveness. The scheme has been compared with the 2-DOF structure control law of modified Smith predictor. The comparative experimental results show that the scheme proposed in this note has a strong disturbance rejection ability and steady-state performance. The controller designed in this note has advantages of simplified construction method, satisfactory control effect and robustness. (shrink)

Classic genetics studies found that genomic imbalance caused by changing the dosage of part of the genome (aneuploidy) has more detrimental effects than altering the dosage of the whole genome (ploidy). Previous analysis revealed global modulation of gene expression triggered by aneuploidy across various species, including maize (Zea mays), Arabidopsis, yeast, mammals, etc. Plant microRNAs (miRNAs) are a class of 20‐ to 24‐nt endogenous small noncoding RNAs that carry out post‐transcriptional gene expression regulation. That miRNAs and their putative targets are (...) preferentially retained as duplicates after whole‐genome duplication, as are many transcription factors and signaling components, indicates miRNAs are likely to be dosage‐sensitive and potentially involved in genomic balance networks. This review addresses the following questions regarding the role of miRNAs in genomic imbalance. (1) How do aneuploidy and polyploidy impact the expression of miRNAs? (2) Do miRNAs play a regulatory role in modulating the expression of their targets under genomic imbalance? (shrink)

Based on a pre-order on a set, we axiomatize the Egli-Milner order on the power set and show how it is related to the Lewis order. Moreover, we consider a strict version of the Egli-Milner order and show how it can be related to the semantics of conditionals based on a priority structure.

For achieving the sustainable development goals, green development has been raised to a high position for cities in China. The economic development in Northwest China is slow, the ecological environment is fragile, and the mineral resources are rich. Only through green development can we realize the comprehensive income of regional production development, rich life, and good ecology. This paper measures the green development efficiency of 30 prefecture-level cities in Northwest China by using DEA-SBM model of unexpected output, explores the differences (...) and causes of green development efficiency from the perspective of time and space through convergence coefficient, coordination matrix, GIS, and other methods, and empirically tests the impact of industrial structure, technological progress, and other driving factors on green development efficiency by using panel Tobit model. The results show that, on the whole, the efficiency of green development in Northwest China is low, path dependence is serious and unbalanced, the coordinated development effect of different regions is weak, and the spillover effect of core urban agglomerations has not been effectively exerted; from the perspective of driving factors, economic development, population density, traffic situation, and education investment can significantly improve the efficiency of urban green development, and the second is that the proportion of industries significantly hinders the improvement of green development efficiency, while the impact of scientific and technological innovation is not significant. Based on the empirical results, this paper believes that the harmonious development of natural environment and economic society can be realized only by improving the coordinated development effect among cities, implementing the optimization and upgrading of industrial structure, introducing excellent talents, and promoting the technological upgrading. (shrink)

To achieve environmental sustainability, the role of human capital and financial inclusion has been debated in limited empirical studies. Employing a reliable ARDL model approach, this study examines the dynamic link between human capital and ICT, financial inclusion, and CO2 emissions using the China economy dataset over the period 1998–2020. The vivacious side of human capital shows that literacy rate and average year of schooling curb CO2 emissions in long run. The results of human capital are also based on facts (...) in magnitude as well as in direction. Also, empirics unfold that digital financial inclusion significantly increases CO2 emissions. Based on these novel findings, a wide set of economic policies are repaired for environmental quality. Environmental education should be considered at early levels of education. The authorities and policymakers should fix energy-related issues through education. The China government should stimulate the educational sector to conduct a clean and green revolution that acts as a mechanism for a green and clean economy. This study's finding is more effective than the previous unlike empirical studies for policy-making because of the advanced econometric method. (shrink)

A growing body of research has started to examine how individuals from different countries may differ in their use of ethically questionable tactics during business negotiations. Whereas prior research focused on the main effect of the national culture or nationality of the negotiator, we add a new factor, which is the nationality of the counterpart. Looking at both these variables allows us to examine whether and how people may change their likelihood of using ethically questionable tactics in inter-cultural negotiations as (...) opposed to intra-cultural ones. Results of an experiment show that overall, American participants were less likely than Chinese participants to use ethically questionable tactics in negotiations. However, American participants were more likely to use ethically questionable tactics, particularly those related to false promises and inappropriate information gathering, in inter-cultural negotiations with Chinese counterparts, than in intra-cultural negotiations with American counterparts. By contrast, Chinese participants were less likely to use ethically questionable tactics, particularly those related to false promises and attacking opponent’s network, in inter-cultural negotiations with American counterparts, than in intra-cultural negotiations with Chinese counterparts. Implications and future directions are discussed. (shrink)

In economic researches, much effort was devoted to the problem of how to increase the economics of countries. However, the development of a country may fluctuate a lot due to international and domestic problems. Thus, we should also evaluate the robustness of countries against unexpected economic recessions. In this paper, we use perturbation to quantify the robustness of countries using two renowned algorithms: method of reflections and fitness-complexity method. The robustness characterizes the stability of countries’ competitiveness against economic recessions. The (...) experiments in the international trade networks show that FCM could characterize the robustness better than MR. High fitness countries of FCM have strong robustness against economic crises, which enlarges the application fields of FCM. Additionally, we simulate the trade conflict between USA and China. The simulation results show that China suffers much in the trade conflict, while USA loses very little and has strong robustness in this conflict. (shrink)

This paper identifies that Information and Communication Technology (ICT) has a negative effect on software piracy rates in addition to consolidating prior research that economic development and the cultural dimension of individualism also negatively affect piracy rates. Using data for 59 countries from 2000 to 2005, the findings show that economic well-being, individualism and technology development as measured by ICT expenditures explain between 70% and 82% of the variation in software piracy rates during this period. The research results provide important (...) implications for policy makers and business practitioners to help reduce software piracy. (shrink)

BackgroundProfessional ethics is the regulation and discipline of nurses’ daily nursing work. Nurses often encounter various ethical challenges and problems in their clinical work, but there are fe...

This essay aims to explore Xunzi’s 荀子 problem, which was originally proposed by David S. Nivison. The problem revolves around a tension in Xunzi’s writings about human nature. In his chapter “Human Nature is Bad (Xing’e 性惡),” Xunzi states that humans have inborn selfish desires and natural feelings, and if they do not control or regulate these desires and feelings, there will certainly be chaos. However, in the chapter “The Regulations of a Sage King (Wangzhi 王制),” Xunzi argues that human (...) beings possess yi 義, which is an important feature distinguishing them from other creatures. I try to analyze how yi should be understood in the Xunzi by focusing on the relationship of yi with fen 分 (division) and li 禮 (ritual). In the process, I also consider Hall and Ames’s understanding of yi as “meaning-bestowing,” and pay attention to Xunzi’s mention that yi is something that enables human beings to jump from natural to social divisions. (shrink)

Recent research has suggested that young children may have primitive knowledge of ratio and proportions. However, it is unclear how precisely young children represent ratio magnitudes and how well...

This article starts with the environmental changes in human cognition, analyzes the virtual as the main feature of visual perception under digital technology, and explores the transition from passive to active human cognitive activities. With the diversified understanding of visual information, human contradiction of memory also began to become prominent. Aiming at the problem that the existing multimodal TV media recognition methods have low recognition rate of unknown application layer protocols, an adaptive clustering method for identifying unknown application layer protocols (...) is proposed. This method clusters application layer protocols based on similarity of the load characteristics of network stream application layer protocol data. The method divides the similarity calculation in the clustering algorithm to improve the clustering efficiency of the algorithm. Experimental results show that the proposed method can efficiently and accurately recognize unknown visual communication. This article proposes that, in the interactive multimodal visual information transmission, human visual perception experience has changed, the diversity of visual information content expression makes the aesthetic subject more personalized and stylized. (shrink)