Description:
Background and aims: Oppositional Defiant Disorder (ODD) is a common childhood disorder (American Psychiatric Association [APA], 2000; APA, 2013). The aim of the present study was to ascertain the optimal structure for the ODD symptoms by identifying whether ODD is a qualitatively distinct entity (categorical) or is a continuum, with high levels on this continuum reflecting ODD (quantitative or dimensional view). Methods: Mothers' ratings of the ODD symptoms of 457 children, aged 3 to 15 years, as presented in the disruptive behavior rating scale were obtained. Confirmatory factor analysis (CFA), latent class analysis (LCA), and factor mixture modelling (FMM) were applied to determine the best model for oppositional defiant disorder (ODD) symptoms in children. Results: The findings provided most support for a FMM with 3 classes (unaffected odd class, at risk class, and affected class) and 3 factors (oppositional, antagonistic, and negative affect). Conclusion: The findings are discussed in relation to dimensional, categorical, and hybrid (categorical/dimensional) models of ODD symptoms.
Description:
In this paper, we present some inverse function theorems and implicit function theorems for set-valued mappings between Fréchet spaces. The proof relies on Lebesgue's Dominated Convergence Theorem and on Ekeland's variational principle. An application to the existence of solutions of differential equations in Fréchet spaces with non-smooth data is given.
Description:
Although the importance of customer orientation (CO) has been recognized, its relationship with firm performance is far from clear. This lack of clarity is partly because the impact of CO on firm performance may depend on certain internal or external factors. Based on social learning theory and an interactional perspective, this study concurrently explores the separate and joint moderating effects of ethical leadership and competitive intensity. Survey data from 264 Chinese firms was collected to test the hypotheses. The results show that humane leadership and moderation leadership help firms to better leverage CO for enhancing their performance. The absence of moderation leadership may be particularly harmful for firms operating in a less competitive environment while the moderating effect is not influenced by competitive intensity. In addition, justice leadership has a positive impact for firms operating in a more competitive environment, which assists firms to better realize the benefits of CO.
Description:
Simulation-based education has become a ubiquitous teaching approach in nursing. However, ensuring the quality of simulation research is critical. We reviewed the methodological quality of 26 quantitative studies published in Clinical Simulation in Nursing, 2017. The Medical Education Research Study Quality Instrument and Simulation Research Evaluation Rubric showed that nearly all studies were of moderate to high quality (rated ≥50%). Correlation coefficients showed that interrater agreement was high overall (≥0.94). In conclusion, this was a valid approach for examining simulation study quality. Although most included studies were of high quality, some elements of study reporting can be improved upon.
Description:
Simulation-based education has become a ubiquitous teaching approach in nursing. However, ensuring the quality of simulation research is critical. We reviewed the methodological quality of 26 quantitative studies published in Clinical Simulation in Nursing, 2017. The Medical Education Research Study Quality Instrument and Simulation Research Evaluation Rubric showed that nearly all studies were of moderate to high quality (rated ≥50%). Correlation coefficients showed that interrater agreement was high overall (≥0.94). In conclusion, this was a valid approach for examining simulation study quality. Although most included studies were of high quality, some elements of study reporting can be improved upon.
Description:
Clinical simulation is an essential component of health professional education. Digital technologies can provide students with near-reality, interactive virtual simulation learning experiences on static and mobile appliances. Clarification is needed, however, regarding the various types of virtual simulation and the different program components. We drew on published literature to define virtual simulation modalities and to offer definitive terminology to clarify the nomenclature and composition of virtual simulation. Reporting should include description of ‘Fidelity’ ‘Immersion’ and ‘Patient’ to add clarity and utility to research in the field.
Description:
In 1972 the orbital engine invented by Sarich (1970, 1973) was widely publicized in Australia. As a result of this publicity two mechanical engineering students at the Gippsland Institute of Advanced Education decided to make the orbital engine the subject matter of their final year project in 1973. Since publicity indicated that Sarich was concentrating his efforts on the development of a four-stroke orbital engine, the students (Joe Rosin and Robert Sincich) and the first author decided to concentrate their efforts on the design of an orbital two-stroke engine.
Description:
This chapter is intended to show that it is possible to obtain a considerable improvement in compressor performance and reliability by modifying the design of the compressor drive. Instead of the traditional slider-crank mechanism, which has been used as a drive since the compressor industry started, it is now possible to replace this drive by more sophisticated ones which offer more flexible stroke design. Such replacement has been made possible by the modern manufacturing methods and analysis tools which are currently at the disposal of industry and research bodies. Earlier work in the domain of proposing new linkages to drive positive displacement machines can be found in the work by Ooi and Wan (2000) who presented a proposal to drive the compressor piston directly from the back using a camlike mechanism. Also, Mimmi and Pennacchi (2001) proposed a pump drive that produces four variable-length strokes per crank revolution. On the other hand, Sultan and Kalim (2011) presented a five-bar geared linkage which can be used to drive a reciprocating compressor instead of the conventional slider-crank mechanism. The next section will present a mathematical model for the compressor operation.
Description:
Positive displacement machines have acquired particular popularity with the current push for sustainable energy production and consumption. It is currently not acceptable to waste energy available in high-pressure gasses throttled or vented to atmosphere in industrial processes (Samuel, 2007; Shu, Yu, Tian, Wei, & Liang, 2014) or blown out of cylinders in large diesel engines (Amann, 1987; Panesar, 2015; Karvountzis-Kontakiotis, Pesiridis, Zhao, Alshammari, et al., 2017). For such applications, a suitably sized positive displacement machine would be employed to harvest energy from these gases and transform it into useful forms. Turbines that are traditionally employed in massive power plants cannot be used for energy harvesting applications due to their inability to handle neither two-phase vapors (Groniewsky, Gy€orke, & Imre, 2017) nor flow occurring at small rates. For these applications, a gas expander, which is a positive displacement machine is usually employed. In relation to pressure creation, positive displacement pumps and compressors are commonly employed to impart pressure to respectively gaseous and liquid fluids flowing at rates which are required by most industries. This chapter presents the limac¸on rotary positive displacement machine, which can be employed for energy production (i.e., as a gas expander) and energy consumption (i.e., as a compressor or a pump) with equal ease and effectiveness. The limac¸on machine (Sultan, 2005) offers a straightforward technology, which has occurred to many creative minds as evident by patents which can be traced back to the 19th century. However, it is unfortunate that such technology did not make it to mass production due to the lack of mathematical understanding of their geometric characteristics and unavailability of manufacturing tools required to machine their chambers. Recently, however, with technical papers published on the topic, industry take-up of the technology has started to emerge. A good example of this take up is shown by the patent of Nystrom (2016).
Description:
This paper presents a canonical d.c. (difference of canonical and convex functions) programming problem, which can be used to model general global optimization problems in complex systems. It shows that by using the canonical duality theory, a large class of nonconvex minimization problems can be equivalently converted to a unified concave maximization problem over a convex domain, which can be solved easily under certain conditions. Additionally, a detailed proof for triality theory is provided, which can be used to identify local extremal solutions. Applications are illustrated and open problems are presented.
Description:
This paper presents a canonical d.c. (difference of canonical and convex functions) programming problem, which can be used to model general global optimization problems in complex systems. It shows that by using the canonical duality theory, a large class of nonconvex minimization problems can be equivalently converted to a unified concave maximization problem over a convex domain, which can be solved easily under certain conditions. Additionally, a detailed proof for triality theory is provided, which can be used to identify local extremal solutions. Applications are illustrated and open problems are presented.
Description:
Positive Displacement Machines are based on the concept of changing the volume available for fluid processing in a manner which produces matching variations in the pressure of that fluid. This is achieved by the use of mechanical linkages specially designed to optimize the pressure-volume relationships in order ofr the machine to perform efficiently. This volume explains the workings of a variety of positive displacement machines which include pumps, compressors, and gas expanders. Presented at a mathematical and technical level, the most influential research in this field over the past decade or so is examined, along with best practice from industry. The work featured here highlights the importance of using the latest computation techniques, and following proper design procedure to achieve the desired outcome.