On the computation of the term w21z2zˉw_{21}z^2\bar{z} of the series defining the center manifold for a scalar delay differential equation

In computing the third order terms of the series of powers of the center manifold at an equilibrium point of a scalar delay differential equation, with a single constant delay $r>0,$ some problems occur at the term $w_{21}z^2\bar{z}.$ More precisely, in order to determine the values at 0, respectively $-r$ of the function $w_{21}(\,.\,),$ an algebraic system of equations must be solved. We show that the two equations are dependent, hence the system has an infinity of solutions. Then we show how we can overcome this lack of uniqueness and provide a formula for $w_{21}(0).$Comment: Presented at the Conference on Applied and Industrial Mathematics- CAIM 2011, Iasi, Romania, 22-25 September, 2011. Preprin

Perceptions of physiotherapists towards research: a mixed methods study

OBJECTIVES: To explore the perceptions of physiotherapists towards the use of and participation in research. DESIGN: Concurrent mixed methods research, combining in-depth interviews with three questionnaires (demographics, Edmonton Research Orientation Survey, visual analogue scales for confidence and motivation to participate in research). SETTING: One physiotherapy department in a rehabilitation hospital, consisting of seven specialised areas. PARTICIPANTS: Twenty-five subjects {four men and 21 women, mean age 38 [standard deviation (SD) 11] years} who had been registered as a physiotherapist for a mean period of 15 (SD 10) years participated in this study. They were registered with the New Zealand Board of Physiotherapy, held a current practising certificate, and were working as a physiotherapist or physiotherapy/allied health manager at the hospital. MAIN OUTCOME MEASURE: The primary outcome measure was in-depth interviews and the secondary outcome measures were the three questionnaires. RESULTS: Physiotherapists were generally positive towards research, but struggled with the concept of research, the available literature and the time to commit to research. Individual confidence and orientation towards research seemed to influence how these barriers were perceived. CONCLUSION: This study showed that physiotherapists struggle to implement research in their daily practice and become involved in research. Changing physiotherapists' conceptions of research, making it more accessible and providing dedicated research time could facilitate increased involvement in the physiotherapy profession

Many-body effects on the capacitance of multilayers made from strongly correlated materials

Recent work by Kopp and Mannhart on novel electronic systems formed at oxide interfaces has shown interesting effects on the capacitances of these devices. We employ inhomogeneous dynamical mean-field theory to calculate the capacitance of multilayered nanostructures. These multilayered nanostructures are composed of semi-infinite metallic leads coupled via a strongly correlated dielectric barrier region. The barrier region can be adjusted from a metallic regime to a Mott insulator through adjusting the interaction strength. We examine the effects of varying the barrier width, temperature, potential difference, screening length, and chemical potential. We find that the interaction strength has a relatively strong effect on the capacitance, while the potential and temperature show weaker dependence.Comment: 19 pages, 7 figures, REVTe

Explaining the energy mix in China’s electricity projects under the belt and road initiative

This paper explains the energy mix of China’s overseas electricity investments across Belt and Road Initiative (BRI) recipient countries. We focus on Indonesia and Pakistan. Our research is based on both newly gathered project-level data and in-depth interviews with stakeholders of Chinese-backed power plants in Indonesia and Pakistan. We examine (1) why Chinese actors are involved in renewable power generation in Pakistan and not in Indonesia, and (2) why Chinese-backed coal-fired projects in Pakistan are cleaner than in Indonesia. We argue that variations along the three dimensions–scope, governance regime, and issue linkage–lead to different energy mixes in Chinese-invested power plants across BRI countries. This framework specifies how supply and demand factors interact across multiple levels regarding the formulation and implementation of China’s overseas electricity projects. Our findings shed new light on the environmental implications of BRI projects and the dynamics of renewable energy development in emerging markets.</p

Computerized Scanning Auger Microprobe

An Auger spectrometer has been automated using a microcomputer. Fundamental considerations in the design and choice of the computerized system are presented and should be of general interest. The spectrometer was a Physical Electronics Ind. model 545 scanning Auger microprobe. The microcomputer chosen was a Southwest Technical Products 6809 computer system. Hardware details are discussed with emphasis on the four computer-spectrometer interface boards. These boards are (1) Auger energy control board, which sets the Auger detection energy with its 16 bit digital-to-analog converter (DAC); (2) read Auger signal board, which reads the Auger signal intensity with its 12 bit analog-to-digital converter; (3) multipurpose DAC board, which uses two pairs of 8 bit DAC\u27s to position the excitation beam and display the data in memory on a CRT monitor, and (4) timing and relay control board, which selects various instruments and power supplies as required during the fully automated depth profiling sputter sequences. Organizational details of the control, analysis, and output software are discussed. The operation of the main Auger control program is emphasized along with its menu driven options, which provide great versatility to the operator. Examples are shown of the various data output modes, which include displays on the CRT monitor and plots from the multicolor digital plotter. © 1985, American Vacuum Society. All rights reserved

Variable-delay feedback control of unstable steady states in retarded time-delayed systems

We study the stability of unstable steady states in scalar retarded time-delayed systems subjected to a variable-delay feedback control. The important aspect of such a control problem is that time-delayed systems are already infinite-dimensional before the delayed feedback control is turned on. When the frequency of the modulation is large compared to the system's dynamics, the analytic approach consists of relating the stability properties of the resulting variable-delay system with those of an analogous distributed delay system. Otherwise, the stability domains are obtained by a numerical integration of the linearized variable-delay system. The analysis shows that the control domains are significantly larger than those in the usual time-delayed feedback control, and that the complexity of the domain structure depends on the form and the frequency of the delay modulation.Comment: 13 pages, 8 figures, RevTeX, accepted for publication in Physical Review