Directional coupler using gap plasmon waveguides

Here, we demonstrate that efficient nano-optical couplers can be developed using closely spaced gap plasmon waveguides in the form of two parallel nano-sized rectangular slots in a thin metal film or membrane. Using the rigorous numerical finite-difference and finite element algorithms, we investigate the physical mechanisms of coupling between two neighboring gap plasmon waveguides and determine typical coupling lengths for different structural parameters of the coupler. Special attention is focused onto the analysis of the effect of such major coupler parameters, such as thickness of the metal film/membrane, slot width, and separation between the plasmonic waveguides. Detailed physical interpretation of the obtained unusual dependencies of the coupling length on slot width and film thickness is presented based upon the energy consideration. The obtained results will be important for the optimization and experimental development of plasmonic sub-wavelength compact directional couplers and other nano-optical devices for integrated nanophotonics.

Fundamental solution and discrete random walk model for time-space fractional diffusion equation

In this paper, we consider a time-space fractional diffusion equation of distributed order (TSFDEDO). The TSFDEDO is obtained from the standard advection-dispersion equation by replacing the first-order time derivative by the Caputo fractional derivative of order α∈(0,1], the first-order and second-order space derivatives by the Riesz fractional derivatives of orders β 1∈(0,1) and β 2∈(1,2], respectively. We derive the fundamental solution for the TSFDEDO with an initial condition (TSFDEDO-IC). The fundamental solution can be interpreted as a spatial probability density function evolving in time. We also investigate a discrete random walk model based on an explicit finite difference approximation for the TSFDEDO-IC.

The evaluation of a biphasic osteochondral implant coupled with an electrospun membrane in a large animal model

Conventional clinical therapies are unable to resolve osteochondral defects adequately, hence tissue engineering solutions are sought to address the challenge. A biphasic implant which was seeded with Mesenchymal Stem Cells (MSC) and coupled with an electrospun membrane was evaluated as an alternative. This dual phase construct comprised of a Polycaprolactone (PCL) cartilage scaffold and a Polycaprolactone - Tri Calcium Phosphate (PCL - TCP) osseous matrix. Autologous MSC was seeded into the entire implant via fibrin and the construct was inserted into critically sized osteochondral defects located at the medial condyle and patellar groove of pigs. The defect was resurfaced with a PCL - collagen electrospun mesh that served as a substitute for periosteal flap in preventing cell leakage. Controls either without implanted MSC or resurfacing membrane were included. After 6 months, cartilaginous repair was observed with a low occurrence of fibrocartilage at the medial condyle. Osteochondral repair was promoted and host cartilage degeneration was arrested as shown by the superior Glycosaminoglycan (GAG) maintenance. This positive morphological outcome was supported by a higher relative Young's modulus which indicated functional cartilage restoration. Bone in growth and remodeling occurred in all groups with a higher degree of mineralization in the experimental group. Tissue repair was compromised in the absence of the implanted cells or the resurfacing membrane. Moreover healing was inferior at the patellar groove as compared to the medial condyle and this was attributed to the native biomechanical features.

Testing the effectiveness of a Practice Development intervention on changing the culture of evidence based practice in an acute care environment

In this age of evidence-based practice, nurses are increasingly expected to use research evidence in a systematic and judicious way when making decisions about patient care practices. Clinicians recognise the role of research when it provides valid, realistic answers in practical situations. Nonetheless, research is still perceived by some nurses as external to practice and implementing research findings into practice is often difficult. Since its conceptual platform in the 1960s, the emergence and growth of Nursing Development Units, and later, Practice Development Units has been described in the literature as strategic, organisational vehicles for changing the way nurses think about nursing by promoting and supporting a culture of inquiry and research-based practice. Thus, some scholars argue that practice development is situated in the gap between research and practice. Since the 1990s, the discourse has shifted from the structure and outcomes of developing practice to the process of developing practice, using a Practice Development methodology; underpinned by critical social science theory, as a vehicle for changing the culture and context of care. The nursing and practice development literature is dominated by descriptive reports of local practice development activity, typically focusing on reflection on processes or outcomes of processes, and describing perceived benefits. However, despite the volume of published literature, there is little published empirical research in the Australian or international context on the effectiveness of Practice Development as a methodology for changing the culture and context of care - leaving a gap in the literature. The aim of this study was to develop, implement and evaluate the effectiveness of a Practice Development model for clinical practice review and change on changing the culture and context of care for nurses working in an acute care setting. A longitudinal, pre-test/post-test, non-equivalent control group design was used to answer the following research questions: 1. Is there a relationship between nurses' perceptions of the culture and context of care and nurses' perceptions of research and evidence-based practice? 2. Is there a relationship between engagement in a facilitated process of Practice Development and change in nurses' perceptions of the culture and context of care? 3. Is there a relationship between engagement in a facilitated process of Practice Development and change in nurses' perceptions of research and evidence-based practice? Through a critical analysis of the literature and synthesis of the findings of past evaluations of Nursing and Practice Development structures and processes, this research has identified key attributes consistent throughout the chronological and theoretical development of Nursing and Practice Development that exemplify a culture and context of care that is conducive to creating a culture of inquiry and evidence-based practice. The study findings were then used in the development, validation and testing of an instrument to measure change in the culture and context of care. Furthermore, this research has also provided empirical evidence of the relationship of the key attributes to each other and to barriers to research and evidence-based practice. The research also provides empirical evidence regarding the effectiveness of a Practice Development methodology in changing the culture and context of care. This research is noteworthy in its contribution to advancing the discipline of nursing by providing evidence of the degree to which attributes of the culture and context of care, namely autonomy and control, workplace empowerment and constructive team dynamics, can be connected to engagement with research and evidence-based practice.

Towards a reference model for SOA governance (extended version)

Although the lack of elaborate governance mechanisms is often seen as the main reason for failures of SOA projects, SOA governance is still very low in maturity. In this paper, we follow a design science approach to address this drawback by presenting a framework that can guide organisations in implementing a governance approach for SOA more successfully. We have reviewed the highly advanced IT governance frameworks Cobit and ITIL and mapped them to the SOA domain. The resulting blueprint for an SOA governance framework was refined based on a detailed literature review, expert interviews and a practical application in a government organisation. The proposed framework stresses the need for business representatives to get involved in SOA decisions and to define benefits ownership for services.

Towards a new employment relationship model

Purpose – The purpose of this study is to examine and extend Noer’s theoretical model of the new employment relationship. Design/methodology/approach – Case study methodology is used to scrutinise the model. The results of a literature-based survey on the elements underpinning the five values in the model are analysed from dual perspectives of individual and organization using a multi-source assessment instrument. A schema is developed to guide and inform a series of focus group discussions from an analysis of the survey data. Using content analysis, the transcripts from the focus group discussions are evaluated using the model’s values and their elements. The transcripts are also reviewed for implicit themes. The case studied is Flight Centre Limited, an Australian-based international retail travel company. Findings – Using this approach, some elements of the five values in Noer’s model are identified as characteristic of the company’s psychological contract. Specifically, to some extent, the model’s values of flexible deployment, customer focus, performance focus, project-based work, and human spirit and work can be applied in this case. A further analysis of the transcripts validates three additional values in the psychological contract literature: commitment; learning and development; and open information. As a result of the findings, Noer’s model is extended to eight values. Research limitations/implications – The study offers a research-based model of the new employment relationship. Since generalisations from the case study findings cannot be applied directly to other settings, the opportunity to test this model in a variety of contexts is open to other researchers. Originality/value – In practice, the methodology used is a unique process for benchmarking the psychological contract. The process may be applied in other business settings. By doing so, organization development professionals have a consulting framework for comparing an organization’s dominant psychological contract with the extended model presented here.