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Z-scan measurements of the nonlinear refractive index of a pumped semiconductor disk laser gain medium
No full textWe measure the nonlinear refractive index of an antiresonant 1050 nm semiconductor disk laser (SDL) gain medium using a reflection-type z-scan system, with a 1064 nm, 10-ps-pulse laser as a probe, and a fiber-coupled 808 nm diode pump laser for carrier injection. Empirically, the nonlinear refractive index is found to depend approximately linearly on applied pump intensity, having a value of −1.5(0.2) × 10−12 cm2/W at zero excitation but increasing to take on positive values at typical SDL operating conditions. The focal lengths of corresponding Kerr lenses calculated using typical SDL pulse intensities and spot sizes are sufficiently short to be comparable to SDL cavity mirrors, implying that Kerr lens modelocking may be responsible for the behavior described in recent reports of self-mode-locked SDLs
Co-operation between different targeting pathways during integration of a membrane protein
No full textMembrane protein assembly is a fundamental process in all cells. The membrane-bound Rieske iron-sulfur protein is an essential component of the cytochrome bc(1) and cytochrome b(6)f complexes, and it is exported across the energy-coupling membranes of bacteria and plants in a folded conformation by the twin arginine protein transport pathway (Tat) transport pathway. Although the Rieske protein in most organisms is a monotopic membrane protein, in actinobacteria, it is a polytopic protein with three transmembrane domains. In this work, we show that the Rieske protein of Streptomyces coelicolor requires both the Sec and the Tat pathways for its assembly. Genetic and biochemical approaches revealed that the initial two transmembrane domains were integrated into the membrane in a Sec-dependent manner, whereas integration of the third transmembrane domain, and thus the correct orientation of the iron-sulfur domain, required the activity of the Tat translocase. This work reveals an unprecedented co-operation between the mechanistically distinct Sec and Tat systems in the assembly of a single integral membrane protein.</p
Transitions to Higher Education:a case study of students in Initial Teacher Education (ITE)
No full textThe aim of this case study is to explore issues relating to Transition into Higher Education for Undergraduate students. The support available to students during this time in their education will also be considered.The study reports on the process of transition for a year group of BEd (Hons) Primary Students. The transitional period in question will take into account the time before the students arrive at the University (applicant status), the time set aside for the induction of students and the time following this allotted transition period, the first four weeks of the semester. Throughout this time, the University as a whole and more specifically, the BEd Programme provide supportive mechanisms for the students. These resources include visit days, an online introduction to the course through the use of the Virtual Learning Environment and an induction programme tailored to the needs of the students.The discussion will take into account the changes for the students during this transitional period. This will focus mainly on the changes to the academic expectations and support of the students.Results have indicated that although the transition has worked well, the students have felt disadvantages in respect of support in academic preparedness and peer/social connections and support. The lack of support through ICT has also been apparent and this appears to be as a consequence of lack of engagement. The impact and implications for use of effective transitional models in Higher Education (HE) will be discussed and explored<br/
SuBETooL ( Sustainable Urban Built Environment Tool), framework and protocol for assessing sustainability. Developed with Hilson Moran and Reading University and put into practice by Hilson Moran in 2009.
No full textThis new framework and tool for assessing the sustainability of masterplans and existing communities is currently used in the industry worldwide. SuBET has been developed over the past 4 years in partnership with Professor Clements-Croome, and Hilson Moran. The strength of SuBETool is that it demonstrates clearly, from the start of masterplanning, what can be achieved in terms of the performance of the proposed development.This framework has changed dramatically the treatment of the masterplanning process as a whole –integrated- system. This has had a major impact on the creation of a more integrated approach for the master planning process benefiting the community of practice, and has achieved International impact in strategic development in the UK, EU and the middle East. This research has replaced, the traditional perspective of master-planning as a linear process concerned with the end state is out-dated and now allows coordination of the plural processes of negotiating sustainable place development.his framework comes with a manual of guidelines which explain explicitly the 75 identified indicators, participation process and the compliance requirement for each indicator, and an assessment system. This proprietary framework has been published internally by Hilson Moran, Husam Al Waer and Derek Croome (2009-present). This framework is available upon request
Ecosystem services:a possible new approach in the valuation of compensation for land expropriation in Cameroon
No full text
The Local Projected Finite Element Method for Maxwell Problem
No full textAn element-local L2-projected C0 finite element method is presented to approximate the nonsmooth solution being not in H1 of the Maxwell problem on a nonconvex Lipschitz polyhedron with reentrant corners and edges. The key idea lies in that element-local L2 projectors are applied to both curl and div operators. The C0 linear finite element (enriched with certain higher degree bubble functions) is employed to approximate the nonsmooth solution. The coercivity in L2 norm is established uniform in the mesh-size, and the condition number O(h-2) of the resulting linear system is proven. For the solution and its curl in Hr with r < 1 we obtain an error bound O(hr) in an energy norm. Numerical experiments confirm the theoretical error bound
Allopurinol Benefits Left Ventricular Mass and Endothelial Dysfunction in Chronic Kidney Disease
No full textAllopurinol ameliorates endothelial dysfunction and arterial stiffness among patients without chronic kidney disease (CKD), but it is unknown if it has similar effects among patients with CKD. Furthermore, because arterial stiffness increases left ventricular afterload, any allopurinol-induced improvement in arterial compliance might also regress left ventricular hypertrophy (LVH). We conducted a randomized, double-blind, placebo-controlled, parallel-group study in patients with stage 3 CKD and LVH. We randomly assigned 67 subjects to allopurinol at 300 mg/d or placebo for 9 months; 53 patients completed the study. We measured left ventricular mass index (LVMI) with cardiac magnetic resonance imaging (MRI), assessed endothelial function by flow-mediated dilation (FMD) of the brachial artery, and evaluated central arterial stiffness by pulse-wave analysis. Allopurinol significantly reduced LVH (P = 0.036), improved endothelial function (P = 0.009), and improved the central augmentation index (P = 0.015). This study demonstrates that allopurinol can regress left ventricular mass and improve endothelial function among patients with CKD. Because LVH and endothelial dysfunction associate with prognosis, these results call for further trials to examine whether allopurinol reduces cardiovascular events in patients with CKD and LVH.</p
Using a touch screen computer to support relationships between people with dementia and caregivers
No full textProgressive and irreversible cognitive impairments affect the ability of people with dementia to communicate and interact with caregivers. This places a burden on caregivers to initiate and manage interactions to the extent that they may avoid all but essential communication. CIRCA is an interactive, multimedia touch screen system that contains a wide range of stimuli to prompt reminiscing. The intention is that people with dementia and caregivers will explore CIRCA together, using the recollections sparked by the media as the basis for conversations. This paper reports an evaluation of the utility of CIRCA looking particularly at whether CIRCA can meet the needs of both people with dementia and caregivers to engage in mutually satisfying interactions. The findings confirm that people with dementia can use the touch screen system and that the contents prompt them to reminisce. The system also supports caregivers to interact with people with dementia as more equal participants in the conversation. The results suggest that interacting with the touch screen system is engaging and enjoyable for people with dementia and caregivers alike and provides a supportive interaction environment that positively benefits their relationships. (C) 2010 Elsevier B.V. All rights reserved.</p
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