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Patients with chronic obstructive pulmonary disease (COPD) suffer from many health problems including poor sleep. This paper aims to evaluate the relationship between diet quality indices (DQIs) and sleep quality in COPD.

The current cross-sectional study was carried on 121 COPD patients. Subjective quality of sleep was determined by Pittsburgh Sleep Quality Index (PSQI) and categorized into “poor” and “good” sleep quality. Dietary history was assessed by the DQIs. Disease status was categorized according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) Guidelines.

In total, 103 men and 18 women with a mean age of 66.1 ±10.9 were studied. The subjects were categorized into four groups based on GOLD; 3.3% of subjects were at Stage 1, 38% in Stage 2, 38% in Stage 3 and 20.7% in Stage 4. In total, 38% of subjects were good, and 62% were bad sleepers according to PSQI score. There was no significant relationship between the severity of COPD and PSQI score. We observed a significant inverse relation between PSQI total score and Mediterranean diet (MED) scale, Healthy Eating Index (HEI)-2010 and HEI-2005 (p = 0.024, 0.037 and 0.024, respectively) in males.

This study showed a high prevalence of poor quality of sleep and sleep disturbances among COPD patients. There was an inverse association between PSQI and sleep disorders and DQIs scores in COPD patients. Regardless of the severity of airflow obstruction, poor diet quality may constitute a risk factor for sleep quality.

A distinctive feature of tilt-rotor UAVs is that they can be fully actuated, whereas in fixed-angle rotor UAVs (e.g. common-type quadrotors, octorotors, etc.), the associated dynamic model is characterized by underactuation. Because of the existence of more control inputs, in tilt-rotor UAVs, there is more flexibility in the solution of the associated nonlinear control problem. On the other side, the dynamic model of the tilt-rotor UAVs remains nonlinear and multivariable and this imposes difficulty in the drone's controller design. This paper aims to achieve simultaneously precise tracking of trajectories and minimization of energy dissipation by the UAV's rotors. To this end elaborated control methods have to be developed.

A solution of the nonlinear control problem of tilt-rotor UAVs is attempted using a novel nonlinear optimal control method. This method is characterized by computational simplicity, clear implementation stages and proven global stability properties. At the first stage, approximate linearization is performed on the dynamic model of the tilt-rotor UAV with the use of first-order Taylor series expansion and through the computation of the system's Jacobian matrices. This linearization process is carried out at each sampling instance, around a temporary operating point which is defined by the present value of the tilt-rotor UAV's state vector and by the last sampled value of the control inputs vector. At the second stage, an H-infinity stabilizing controller is designed for the approximately linearized model of the tilt-rotor UAV. To find the feedback gains of the controller, an algebraic Riccati equation is repetitively solved, at each time-step of the control method. Lyapunov stability analysis is used to prove the global stability properties of the control scheme. Moreover, the H-infinity Kalman filter is used as a robust observer so as to enable state estimation-based control. The paper's nonlinear optimal control approach achieves fast and accurate tracking of reference setpoints under moderate variations of the control inputs. Finally, the nonlinear optimal control approach for UAVs with tilting rotors is compared against flatness-based control in successive loops, with the latter method to be also exhibiting satisfactory performance.

So far, nonlinear model predictive control (NMPC) methods have been of questionable performance in treating the nonlinear optimal control problem for tilt-rotor UAVs because NMPC's convergence to optimum depends often on the empirical selection of parameters while also lacking a global stability proof. In the present paper, a novel nonlinear optimal control method is proposed for solving the nonlinear optimal control problem of tilt rotor UAVs. Firstly, by following the assumption of small tilting angles, the state-space model of the UAV is formulated and conditions of differential flatness are given about it. Next, to implement the nonlinear optimal control method, the dynamic model of the tilt-rotor UAV undergoes approximate linearization at each sampling instance around a temporary operating point which is defined by the present value of the system's state vector and by the last sampled value of the control inputs vector. The linearization process is based on first-order Taylor series expansion and on the computation of the associated Jacobian matrices. The modelling error, which is due to the truncation of higher-order terms from the Taylor series, is considered to be a perturbation that is asymptotically compensated by the robustness of the control scheme. For the linearized model of the UAV, an H-infinity stabilizing feedback controller is designed. To select the feedback gains of the H-infinity controller, an algebraic Riccati equation has to be repetitively solved at each time-step of the control method. The stability properties of the control scheme are analysed with the Lyapunov method.

There are no research limitations in the nonlinear optimal control method for tilt-rotor UAVs. The proposed nonlinear optimal control method achieves fast and accurate tracking of setpoints by all state variables of the tilt-rotor UAV under moderate variations of the control inputs. Compared to past approaches for treating the nonlinear optimal (H-infinity) control problem, the paper's approach is applicable also to dynamical systems which have a non-constant control inputs gain matrix. Furthermore, it uses a new Riccati equation to compute the controller's gains and follows a novel Lyapunov analysis to prove global stability for the control loop.

There are no practical implications in the application of the nonlinear optimal control method for tilt-rotor UAVs. On the contrary, the nonlinear optimal control method is applicable to a wider class of dynamical systems than approaches based on the solution of state-dependent Riccati equations (SDRE). The SDRE approaches can be applied only to dynamical systems which can be transformed to the linear parameter varying (LPV) form. Besides, the nonlinear optimal control method performs better than nonlinear optimal control schemes which use approximation of the solution of the Hamilton–Jacobi–Bellman equation by Galerkin series expansions. The stability properties of the Galerkin series expansion-based optimal control approaches are still unproven.

The proposed nonlinear optimal control method is suitable for using in various types of robots, including robotic manipulators and autonomous vehicles. By treating nonlinear control problems for complicated robotic systems, the proposed nonlinear optimal control method can have a positive impact towards economic development. So far the method has been used successfully in (1) industrial robotics: robotic manipulators and networked robotic systems. One can note applications to fully actuated robotic manipulators, redundant manipulators, underactuated manipulators, cranes and load handling systems, time-delayed robotic systems, closed kinematic chain manipulators, flexible-link manipulators and micromanipulators and (2) transportation systems: autonomous vehicles and mobile robots. Besides, one can note applications to two-wheel and unicycle-type vehicles, four-wheel drive vehicles, four-wheel steering vehicles, articulated vehicles, truck and trailer systems, unmanned aerial vehicles, unmanned surface vessels, autonomous underwater vessels and underactuated vessels.

The proposed nonlinear optimal control method is a novel and genuine result and is used for the first time in the dynamic model of tilt-rotor UAVs. The nonlinear optimal control approach exhibits advantages against other control schemes one could have considered for the tilt-rotor UAV dynamics. For instance, (1) compared to the global linearization-based control schemes (such as Lie algebra-based control or flatness-based control), it does not require complicated changes of state variables (diffeomorphisms) and transformation of the system's state-space description. Consequently, it also avoids inverse transformations which may come against singularity problems, (2) compared to NMPC, the proposed nonlinear optimal control method is of proven global stability and the convergence of its iterative search for an optimum does not depend on initialization and controller's parametrization, (3) compared to sliding-mode control and backstepping control the application of the nonlinear optimal control method is not constrained into dynamical systems of a specific state-space form. It is known that unless the controlled system is found in the input–output linearized form, the definition of the associated sliding surfaces is an empirical procedure. Besides, unless the controlled system is found in the backstepping integral (triangular) form, the application of backstepping control is not possible, (4) compared to PID control, the nonlinear optimal control method is of proven global stability and its performance is not dependent on heuristics-based selection of parameters of the controller and (5) compared to multiple-model-based optimal control, the nonlinear optimal control method requires the computation of only one linearization point and the solution of only one Riccati equation.

Recognizing that the nature of research and scholarly communication is changing rapidly, an institutional repository (IR) is a tool for collecting, storing, accessing and disseminating scholarly communication within and without the institutions. The primary reason for establishing an IR is to increase the visibility of the institution’s research output by making it an open access with regard to copyright issues. This paper aims to propose a conceptualmodel for scholarly communication through IRs to provide an opportunity to integrate and facilitate knowledge sharing so as to enrich knowledge content and enhance global access.

This paper proceeds in three phases. In the first phase, the published literature on IRs and scholarly communication has been reviewed critically considering their empirical applications. Next, based on the understanding gained from the previous stage, a conceptual model for scholarly communication through IRs has been proposed. In the third phase, the proposed model has been developed and finalized toward its maturity.

Based on the literature, the authors have developed a conceptual model for understanding the factors that characterize not only the design but also the development of IRs practically. An IR appears theoretically sound, but it is a difficult task in practice because of some complexities. This paper attempts to set a theoretical model for IRs as a foundation to address the gap in the current literature for researchers, experts and librarians who create, maintain and use IRs, though it does not claim to be comprehensive.

A few attempts have been made to investigate scholarly communication through IRs, but this is the one of its first kind that provides a theoretical model for it. It serves as a useful starting point for those interested in knowledge management and IRs.

Valid and reliable measures are required for assessing patient satisfaction meaningfully. The purpose of this paper was to develop and validate a Persian-language in-patient satisfaction questionnaire for patients discharged from Iranian medical and surgical services.

The cross-sectional survey included 400 patients randomly selected from six Tehran hospitals. A total of 405 patients responded to the questionnaire (76.3 percent response). To assess inter-item reliability and construct validity, factor analysis was carried out. Items belonging to each factor and their Cronbach's alpha coefficient were calculated.

A total of seven dimensions were identified: doctor-patient communication; nursing care; convenience; visitors; cleanliness; costs; and general satisfaction. Together, these dimensions explained 60 percent of the variance. All items, except three, revealed loadings above 0.4, while Cronbach's alpha exceeded 0.8 for all dimensions, except visitors (0.66). Patient satisfaction levels were relatively high.

Results must be interpreted cautiously owing to high satisfaction, which should not be considered as comprehensive evidence of high performance without important additional service-performance information. Qualitative studies are recommended to complement the authors' quantitative satisfaction study.

The patient satisfaction questionnaire strives to be a valid and reliable instrument for assessing in-patient satisfaction with hospital services in Iran.

Culture is considered a critical aspect of social media usage. The purpose of this paper is to explore how cultures and languages influence multilingual users' cross-cultural information sharing patterns.

This study used a crowdsourcing survey with Amazon Mechanical Turk to collect qualitative and quantitative data from 355 multilingual users who utilize two or more languages daily. A mixed-method approach combined statistical, and cluster analysis with thematic analysis was employed to analyze information sharing patterns among multilingual users in the Chinese cultural context.

It was found that most multilingual users surveyed preferred to share in their first and second language mainly because that is what others around them speak or use. Multilingual users have more diverse sharing characteristics and are more actively engaged in social media. The results also provide insights into what incentives make multilingual users engage in social media to share information related to Chinese culture with the MOA model. Finally, the ten motivation factors include learning, entertainment, empathy, personal gain, social engagement, altruism, self-expression, information, trust and sharing culture. One opportunity factor is identified, which is convenience. Three ability factors are recognized consist of self-efficacy, habit and personality.

The findings are conducive to promoting the active participation of multilingual users in online communities, increasing global resource sharing and information flow and promoting the consumption of digital cultural content.

In recent years, entrepreneurship education has become increasingly popular to promote economic development and encourage entrepreneurship. This chapter aims to review the effectiveness of entrepreneurship education and the mode of delivery. This review will help understand the effectiveness of entrepreneurship education (entrepreneurial skills, entrepreneurial intention, enhanced entrepreneurial mindset and greater business success). It will also help understand the mode of delivery (classroom instruction, experiential learning, mentoring and coaching and online learning) Using the traditional review methodology, the chapter focusses on the outcomes of entrepreneurship education on students and their attitudes, intentions and behaviours towards entrepreneurship. The chapter also evaluates the various modes of delivery, including traditional classroom-based instruction, experiential learning and online education. The review compared the United States of America and South African points of view on entrepreneurship education to posit significant directions on how to effectuate entrepreneurship education. The chapter further reviews the sustainable development goals that are aligned with entrepreneurship. Overall, the chapter concludes that entrepreneurship education is effective in promoting entrepreneurial attitudes, intentions and behaviours, and its mode of delivery significantly influences its impact. The chapter recommends the integration of active and experiential learning methods into entrepreneurship education, and the development of innovative modes of delivery to reach a wider audience. Policymakers should also support the integration of entrepreneurship education into the formal education system to promote economic development.

The purpose of this paper is to study the flow, heat and mass transfer of MHD Casson nanofluid due to an inclined stretching sheet using similarity transformation, the governing PDE’S equations of flow, heat and mass transfer are converted into ODE’S. The resulting non-linear ODE’S are solved numerically using an implicit finite difference method, which is known as Kellor-box method. The effects of various governing parameters on velocity, temperature and concentration are plotted for both Newtonian and non-Newtonian cases. The numerical values of skin friction, Nusselt number and Sherwood number are calculated and tabulated in various tables for different values of physical parameters. It is noticed that the effect of angle of inclination enhances the temperature and concentration profile whereas velocity decreases. The temperature decreases due to the increase in the parametric values of Pr and Gr due to thickening in the boundary layer.

Numerical method is applied to find the results.

Flow and heat transfer analysis w.r.t various flow and temperature are analyzed for different values of the physical parameters.

The numerical values of skin friction, Nusselt number and Sherwood number are calculated and tabulated in various tables for different values of physical parameters.

The study of the boundary layer flow, heat and mass transfer is important due to its applications in industries and many manufacturing processes such as aerodynamic extrusion of plastic sheets and cooling of metallic sheets in a cooling bath.

Here in this paper the authors have investigated the MHD boundary layer flow of a Casson nanofluid over an inclined stretching sheet along with the Newtonian nanofluid as a limited.

This paper’s aim is to inspect the influence of trust, motivation and rewards on knowledge-sharing attitudes among secondary and higher secondary students in Bangladesh.

A sample of 200 Bangladeshi students from secondary and higher secondary-level educational institutions in Dhaka city participated in this study. Data were analysed using exploratory factor analysis followed by confirmatory factor analysis and structural equation modelling techniques.

The findings suggested that trust variables play a significant role in encouraging knowledge-sharing behaviour among the students.

This research also provides a guideline to teachers and policymakers on enhancing a knowledge-sharing environment among secondary and higher secondary-level students.

This paper is a pioneer in understanding knowledge-sharing patterns among secondary and higher secondary students in a developing country such as Bangladesh.

The purpose of this paper is to examine e-service quality (E-SQ) of online shopping in Pakistan using “E-S-QUAL scale.” Moreover, in this study, the relationship of E-SQ with e-customer satisfaction (E-CS) and e-customer loyalty (E-CL) has been studied.

Following a quantitative research methodology, data were collected from 298 respondents using convenience sampling and survey research design was followed. In order to develop the model and test the hypotheses, structure equation modeling (SEM) was done through AMOS.

Findings indicate that all of the first latent constructs are significant where E-CS and E-CL (dependent variables) are influenced by E-SQ (independent variable). Using SEM, statistically fit structural model was developed on the basis of confirmatory factor analysis. The analysis shows that there is a strong positive relation between E-SQ and E-CS and E-SQ and E-CL.

Asian markets have been identified as the fastest growing e-commerce markets in present era. Similarly, retail sector in Pakistan is booming, at the same time an exponential increase is being observed in the number of internet users and online shopping. It is important for marketers and retailers to explore new horizons and enter the age of e-commerce for expansion of their businesses.

The increasingly wide use of the internet is influencing everything around the globe and these emerging e-commerce trends have tremendously changed the mode of shopping from brick and mortars to e-stores. The study explores the e-commerce and focuses on E-SQ and its impact on E-CS and E-CL in the context of a developing economy, i.e. Pakistan, uncovering the key dimensions and attributes.

Using the resource-based and the resource dependence theoretical approaches of the firm, the paper explores firm responses to supply chain disruptions during COVID-19. The paper explores how firms develop localization, agility and digitization (L-A-D) capabilities by applying (or not applying) their critical circular economy (CE) and blockchain technology (BCT)-related resources and capabilities that they either already possess or acquire from external agents.

An abductive approach, applying exploratory qualitative research was conducted over a sample of 24 firms. The sample represented different industries to study their critical BCT and CE resources and capabilities and the L-A-D capabilities. Firm resources and capabilities were classified using the technology, organization and environment (TOE) framework.

Findings show significant patterns on adoption levels of the blockchain-enabled circular economy system (BCES) and L-A-D capability development. The greater the BCES adoption capabilities, the greater the L-A-D capabilities. Organizational size and industry both influence the relationship between BCES and L-A-D. Accordingly, research propositions and a research framework are proposed.

Given the limited sample size, the generalizability of the findings is limited. Our findings extend supply chain resiliency research. A series of propositions provide opportunities for future research. The resource-based view and resource-dependency theories are useful frameworks to better understanding the relationship between firm resources and supply chain resilience.

The results and discussion of this study serve as useful guidance for practitioners to create CE and BCT resources and capabilities for improving supply chain resiliency.

The study shows the socio-economic and socio-environmental importance of BCES in the COVID-19 or similar crises.

The study is one of the initial attempts that highlights the possibilities of BCES across multiple industries and their value during pandemics and disruptions.