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Integrating turbulence into stellarator optimization is shown by targeting the onset for the ion-temperature-gradient mode, highlighting effects of parallel connection length, local magnetic shear, and flux surface expansion. The result is a compact quasihelically symmetric stellarator configuration, admitting a set of uncomplicated coils, with significantly reduced turbulent heat fluxes compared to a known stellarator. The new configuration combines low values of neoclassical transport, good alpha particle confinement, and Mercier stability at a plasma beta of almost 2$\%$., Comment: 5 pages, 5 figures

Nine stellarator configurations, three quasiaxisymmetric, three quasihelically symmetric and three non-quasisymmetric are scaled to ARIES-CS size and analyzed for energetic particle content. The best performing configurations with regard to energetic particle confinement also perform the best on the neoclassical {\Gamma}c metric, which attempts to align contours of the second adiabatic invariant with flux surfaces. Quasisymmetric configurations that simultaneously perform well on {\Gamma}c and quasisymmetry have the best overall confinement, with collisional losses under 3%, approaching the performance of ITER with ferritic inserts., Comment: 18 pages, 10 figures, 1 Table

Wendelstein 7-X is the first comprehensively optimized stellarator aiming at good confinement with plasma parameters relevant to a future stellarator power plant. Plasma operation started in 2015 using a limiter configuration. After installing an uncooled magnetic island divertor, extending the energy limit from 4 to 80 MJ, operation continued in 2017. For this phase, the electron cyclotron resonance heating (ECRH) capability was extended to 7 MW, and hydrogen pellet injection was implemented. The enhancements resulted in the highest triple product (6.5 × 1019 keV m-3 s) achieved in a stellarator until now. Plasma conditions [Te(0) ≈ Ti(0) ≈ 3.8 keV, τE > 200 ms] already were in the stellarator reactor-relevant ion-root plasma transport regime. Stable operation above the 2nd harmonic ECRH X-mode cutoff was demonstrated, which is instrumental for achieving high plasma densities in Wendelstein 7-X. Further important developments include the confirmation of low intrinsic error fields, the observation of current-drive induced instabilities, and first fast ion heating and confinement experiments. The efficacy of the magnetic island divertor was instrumental in achieving high performance in Wendelstein 7-X. Symmetrization of the heat loads between the ten divertor modules could be achieved by external resonant magnetic fields. Full divertor power detachment facilitated the extension of high power plasmas significantly beyond the energy limit of 80 MJ.

In order to capture different aspects of change within different actor groups of a distribution network, a network-as-practice perspective (NPP) is used in this study, which looks at performative aspects of an exchange system. This approach, based on the ‘practice-turn’, is framing the development of an analytical framework, which describes practices, translations, as well as mediations of change within the business network. The NPP is suggested as an alternative to traditional business marketing perspective, e.g. those of the Industrial Network Approach (INA). Based on a case-study approach, we analyse the UK pharmaceutical distribution network between 2007 and 2011. Of particular interest are the network dynamics, i.e. changes between the past and today. We focus on a limited number of pertinent themes of network dynamics especially those relating to the introduction of single-wholesaler distribution schemes by manufacturers. This change has caused a strong and recognised instability in the network, which lead to considerable tension between the main actors of the UK pharmaceutical network. There exists also a high level of uncertainty regarding what each actor can or ‘should’ do. By analysing the UK pharmaceutical network as a case and by exploring the processes of interactions, translations, and mediations in this unstable network, our paper contributes to the growing body of literature on network dynamics and reinforces using a practice perspective within the INA.

OBJECTIVE To evaluate the accuracy of a modification of the carbon monoxide method of estimating the circulating blood volume. DESIGN Prospective, clinical study comparing two methods for estimating the circulating blood volume. Carbon monoxide kinetics were studied by computer simulation. SETTING Intensive care unit in a university hospital. PATIENTS Intensive care patients receiving intermittent positive-pressure ventilation and healthy volunteers. MEASUREMENTS AND MAIN RESULTS The circulating blood volume was determined from measurements of the carbon monoxide saturation of hemoglobin before and after rebreathing a gas mixture containing 20 to 50 mL of carbon monoxide for a period of 10 to 15 mins. A specially designed Water's "to & fro" system was developed to avoid any leakage during intermittent positive-pressure ventilation. Blood samples were taken before, during, and immediately after rebreathing. The amount of carbon monoxide administrated during each rebreathing maneuver resulted in an average increase in the carbon monoxide saturation of hemoglobin of 3.6%. The washin of carbon monoxide was completed within the first 4 to 6 mins of the rebreathing period in nine healthy subjects and within 10 mins in 12 intensive care patients. The 95% limits of agreement between the carbon monoxide method and the radioactive isotope-labeling method was +/- 540 mL (+/- 2 SD). CONCLUSION Determination of circulating blood volume can be performed with sufficient accuracy using an amount of carbon monoxide that gives rise to an unharmful increase in the carboxyhemoglobin concentration.

INTRODUCTION: Post-operative agitation (PA) is a common problem (20-70%) in children anaesthetised with sevoflurane. Clonidine is widely used off-label in children for several indications, including PA; but the current level of evidence is limited. Our aim is to investigate the impact of prophylactic intravenous (IV) clonidine administered at the end of surgery on the incidence and degree of PA. Furthermore, the pharmacokinetic profile of IV clonidine in children is not well established and our aim is to obtain pharmacokinetic data relating hereto. METHODS: This is a multicentre, randomised and blinded clinical trial in which we will be enrolling 380 children aged 1-5 years who are planned for anaesthesia with sevoflurane and fentanyl. Inclusion is based on computer-generated randomisation (1: 1) and stratified by age and site. The study drug is administered IV approximately 20 min. before the expected completion of surgery (intervention: clonidine 3 mu g per kg; placebo: equal quantity of saline). CONCLUSION: The primary outcome is PA measured on the Watcha scale. The secondary outcomes include post-operative pain relief and adverse effects, including a 30-day follow- up. In total, 40 children will be allocated to drug assay sampling, enabling a compartmental pharmacokinetic analysis.

Udgivelsesdato: 2010-Mar-22

A steady stream of sales revenue for a service provider can be achieved through having superior market performance outcomes such a high price premium. Among the variables underlying customer relationships is the perceptions of quality received. However for relationships to be mutually profitable the customer s willingness to pay must be taken into account (Ravald and Gronroos (1996). This indicator of market performance outcomes is directly related to service loyalty (Aaker 1991, 1996; Chaudhuri and Holbrook 2001). Achieving and maintaining a high price premium through attracting and retaining a loyal customer base is particularly significant in a business-to-business market. Nevertheless, there are opposing viewpoints in that loyal customers are not always seen as profitable despite arguments that loyalty makes customers less price sensitive.