Bose-Einstein condensate in a quartic potential:static and dynamic properties

In this paper, we present a theoretical study of a Bose-Einstein condensate of interacting bosons in a quartic trap in one, two, and three dimensions. Using Thomas-Fermi approximation, suitably complemented by numerical solutions of the Gross-Pitaevskii equation, we study the ground sate condensate density profiles, the chemical potential, the effects of cross-terms in the quartic potential, temporal evolution of various energy components of the condensate, and width oscillations of the condensate. Results obtained are compared with corresponding results for a bose condensate in a harmonic confinement.

The effect of whole body vibration on oxygen uptake and electromyographic signal of the rectus femoris muscle during static and dynamic squat

Whole Body Vibrations consist of a vibration stimulus mechanically transferred to the body. The impact of vibration treatment on specific muscular activity, neuromuscular, and postural control has been widely studied. We investigated whole body vibration (WBV) effect on oxygen uptake and electromyographic signal of the rectus femoris muscle during static and dynamic squat. Fourteen healthy subjects performed a static and dynamic squat with and without vibration. During the vibration exercises, a significant increase was found in oxygen uptake (P=0.05), which increased by 44% during the static squat and 29.4% during the dynamic squat. Vibration increased heart rate by 11.1 ± 9.1 beats.min-1 during the static squat and 7.9 ± 8.3 beats.min-1 during the dynamic squat. No significant changes were observed in rate of perceived exertion between the exercises with and without vibration. The results indicate that the static squat with WBV produced higher neuromuscular and cardiorespiratory system activation for exercise duration ?60 sec. Otherwise, if the single bout duration was higher than 60 sec, the greater cardiorespiratory system activation was achieved during the dynamic squat with WBV while higher neuromuscular activation was still obtained with the static exercise.

Neuromuscular response to whole body vibration treatment during static and dynamic squat exercises

The impact of whole body vibrations (vibration stimulus mechanically transferred to the body) on muscular activity and neuromuscular response has been widely studied but without standard protocol and by using different kinds of exercises and parameters. In this study, we investigated how whole body vibration treatments affect electromyographic signal of rectus femoris during static and dynamic squat exercises. The aim was the identification of squat exercise characteristics useful to maximize neuromuscular activation and hence progress in training efficacy. Fourteen healthy volunteers performed both static and dynamic squat exercises without and with vibration treatments. Surface electromyographic signals of rectus femoris were recorded during the whole exercise and processed to reduce artifacts and to extract root mean square values. Paired t-test results demonstrated an increase of the root mean square values (p<0.05) in both static and dynamic squat exercises with vibrations respectively of 63% and 108%. For each exercise, subjects gave a rating of the perceived exertion according to the Borg's scale but there were no significant changes in the perceived exertion rate between exercises with and without vibration. Finally, results from analysis of electromyographic signals identified the static squat with WBV treatment as the exercise with higher neuromuscular system response. © 2012 IEEE.

The value of tablets as reading aids for individuals with central visual field loss:an evaluation of eccentric reading with static and scrolling text

Purpose: Technological devices such as smartphones and tablets are widely available and increasingly used as visual aids. This study evaluated the use of a novel app for tablets (MD_evReader) developed as a reading aid for individuals with a central field loss resulting from macular degeneration. The MD_evReader app scrolls text as single lines (similar to a news ticker) and is intended to enhance reading performance using the eccentric viewing technique by both reducing the demands on the eye movement system and minimising the deleterious effects of perceptual crowding. Reading performance with scrolling text was compared with reading static sentences, also presented on a tablet computer. Methods: Twenty-six people with low vision (diagnosis of macular degeneration) read static or dynamic text (scrolled from right to left), presented as a single line at high contrast on a tablet device. Reading error rates and comprehension were recorded for both text formats, and the participant’s subjective experience of reading with the app was assessed using a simple questionnaire. Results: The average reading speed for static and dynamic text was not significantly different and equal to or greater than 85 words per minute. The comprehension scores for both text formats were also similar, equal to approximately 95% correct. However, reading error rates were significantly (p=0.02) less for dynamic text than for static text. The participants’ questionnaire ratings of their reading experience with the MD_evReader were highly positive and indicated a preference for reading with this app compared with their usual method. Conclusions: Our data show that reading performance with scrolling text is at least equal to that achieved with static text and in some respects (reading error rate) is better than static text. Bespoke apps informed by an understanding of the underlying sensorimotor processes involved in a cognitive task such as reading have excellent potential as aids for people with visual impairments.

Executive remuneration, financial performance and corporate governance in UK and Spanish listed firms

This study examines the relationship between executive directors’ remuneration and the financial performance and corporate governance arrangements of the UK and Spanish listed firms. These countries’ corporate governance framework has been shaped by differences in legal origin, culture and backgrounds. For example, the UK legal arrangements can be defined as to be constituted in common-law, whereas for Spanish firms, the legal arrangement is based on civil law. We estimate both static and dynamic regression models to test our hypotheses and we estimate our regression using Ordinary Least Squares (OLS) and the Generalised Method of Moments (GMM). Estimated results for both countries show that directors’ remuneration levels are positively related with measures of firm value and financial performance. This means that remuneration levels do not lead to a point whereby firm value is reduced due to excessive remuneration. These results hold for our long-run estimates. That is, estimates based on panel cointegration and panel error correction. Measures of corporate governance also impacts on the level of executive pay. Our results have important implications for existing corporate governance arrangements and how the interests of stakeholders are protected. For example, long-run results suggest that directors’ remuneration adjusts in a way to capture variation in financial performance

Simulation and experimental analysis of a brushless electrically excited synchronous machine with a hybrid rotor

Electrically excited synchronous machines with brushes and slip rings are popular but hardly used in inflammable and explosive environments. This paper proposes a new brushless electrically excited synchronous motor with a hybrid rotor. It eliminates the use of brushes and slip rings so as to improve the reliability and cost-effectiveness of the traction drive. The proposed motor is characterized with two sets of stator windings with two different pole numbers to provide excitation and drive torque independently. This paper introduces the structure and operating principle of the machine, followed by the analysis of the air-gap magnetic field using the finite-element method. The influence of the excitation winding's pole number on the coupling capability is studied and the operating characteristics of the machine are simulated. These are further examined by the experimental tests on a 16 kW prototype motor. The machine is proved to have good static and dynamic performance, which meets the stringent requirements for traction applications.

Outer rotor mechanical and dynamic performance analysis for high-speed machine

Due to high-speed rotation, the problems about rotor mechanics and dynamics for outer rotor high-speed machine are more serious than conventional ones, in view of above problems the mechanical and dynamics analysis for an outer rotor high-speed permanent magnet claw pole motor are carried out. The rotor stress analytical calculation model was derived, then the stress distribution is calculated by finite element method also, which is coincided with that calculated by analytical model. In addition, the stress distribution of outer rotor yoke and PMs considering centrifugal force and temperature effect has been calculated, some influence factors on rotor stress distribution have been analyzed such as pole-arc coefficient and speed. The rotor natural frequency and critical speed were calculated by vibration mode analysis, and its dynamics characteristics influenced by gyroscope effect were analyzed based on Campbell diagram. Based on the analysis results above an outer rotor permanent magnet high-speed claw pole motor is design and verified.

Genetics and competing strategies in a threshold model for mail processing

Multi-agent algorithms inspired by the division of labour in social insects are applied to a problem of distributed mail retrieval in which agents must visit mail producing cities and choose between mail types under certain constraints.The efficiency (i.e. the average amount of mail retrieved per time step), and the flexibility (i.e. the capability of the agents to react to changes in the environment) are investigated both in static and dynamic environments. New rules for mail selection and specialisation are introduced and are shown to exhibit improved efficiency and flexibility compared to existing ones. We employ a genetic algorithm which allows the various rules to evolve and compete. Apart from obtaining optimised parameters for the various rules for any environment, we also observe extinction and speciation. From a more theoretical point of view, in order to avoid finite size effects, most results are obtained for large population sizes. However, we do analyse the influence of population size on the performance. Furthermore, we critically analyse the causes of efficiency loss, derive the exact dynamics of the model in the large system limit under certain conditions, derive theoretical upper bounds for the efficiency, and compare these with the experimental results.

Strategy, IT and dynamic change in enterprises

This paper explores the importance of collaboration between different types of organizations within an enterprise. To achieve successful collaboration requires both endogenous and exogenous factors of each organization to be considered and a shared meta-strategy supported by shared cross-organizational processes and technology. A rolling business plan would periodically review, assess and reposition each organization within this meta-strategy according to how well they have contributed. We show that recent technological advances have made organizational structures more agile, organizational infra-structure more connected and the sharing of real-time information an operational reality; we also discuss the challenges and risks.

Hypervalent iodine in synthesis. 90. A mild and efficient method for the iodination of pyrazoles

The combined reagent of iodobenzene diacetate (or polymer-supported iodobenzene diacetate) with iodine was used as an effective iodinating agent of pyrazoles to the corresponding 4-iodopyrazole derivatives at room temperature with high yields.

Hypervalent iodine in synthesis 91: a mild and efficient method for the halogenation of 6-methyluracil derivatives

The combined reagent of iodobenzene diacetate (or polymer-supported iodobenzene diacetate) with iodine or bromine was used as an effective halogenative agent of 6-methyluracil derivatives to the corresponding 5-halo-6-methyluracil derivatives at room temperature with high yields.

Gas-fired radiant heaters

This dissertation covers four areas of particular interest for the successful application of radiant heating in industrial environments. In it the author tackles the problem of how to predict the thermal comfort produced both by single heaters and also systems of heaters; proposes a method for modelling the mechanisms by which heaters interact with the buildings in which they are installed, in the static and dynamic cases; explores techniques for measuring the radiation produced by heaters; and presents experiments concerned with finding the temperatures and power balances prevailing during normal operation. It is contended that, whilst the generally accepted guides for sizing and operating space heating plant were a good first approximation, there are intrinsic subtleties arising from the fact that the primary mode of heat transfer in this instance is radiative. These nuances are concerned with how best to maximise the heat transfer from the heat source to the heated object; the placement of heaters within a system; and an assessment of the various techniques and strategies involved in controlling a radiant heating system. The conclusions reached are that: if sized and controlled correctly radiant heating systems offer considerable operational advantages over other types of space heating systems in certain applications, in terms of both economy and controllability. The efficacy of radiant heating systems is affected primarily by the control strategy implemented; secondarily, by the structure of the building into which it is installed; and only marginally by all other factors.

Combining data driven programming with component based software development:with applications in geovisualisation and dynamic data driven application systems

Software development methodologies are becoming increasingly abstract, progressing from low level assembly and implementation languages such as C and Ada, to component based approaches that can be used to assemble applications using technologies such as JavaBeans and the .NET framework. Meanwhile, model driven approaches emphasise the role of higher level models and notations, and embody a process of automatically deriving lower level representations and concrete software implementations. The relationship between data and software is also evolving. Modern data formats are becoming increasingly standardised, open and empowered in order to support a growing need to share data in both academia and industry. Many contemporary data formats, most notably those based on XML, are self-describing, able to specify valid data structure and content, and can also describe data manipulations and transformations. Furthermore, while applications of the past have made extensive use of data, the runtime behaviour of future applications may be driven by data, as demonstrated by the field of dynamic data driven application systems. The combination of empowered data formats and high level software development methodologies forms the basis of modern game development technologies, which drive software capabilities and runtime behaviour using empowered data formats describing game content. While low level libraries provide optimised runtime execution, content data is used to drive a wide variety of interactive and immersive experiences. This thesis describes the Fluid project, which combines component based software development and game development technologies in order to define novel component technologies for the description of data driven component based applications. The thesis makes explicit contributions to the fields of component based software development and visualisation of spatiotemporal scenes, and also describes potential implications for game development technologies. The thesis also proposes a number of developments in dynamic data driven application systems in order to further empower the role of data in this field.