452 research outputs found

    Simulation of noise within BOTDA and COTDR systems to study the impact on dynamic sensing

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    Abstract Real-time structural health monitoring requires dynamic sensing of distributed strain and temperature. Brillouin Optical Time Domain Analysis (BOTDA) and Rayleigh Coherent Optical Time Domain Reflectometry (COTDR) are promising candidates to achieve dynamic sensing. A noise model with specific parametric simulation of independent laser and detector noise sources has been developed. Although ensemble averaging significantly enhances the signal-to-noise ratio (SNR) in both systems, its time-consuming accumulation procedure prevents dynamic sensing. The sequence of averaging in the signal processing workflow varies the SNR for both systems. The system components should be optimized to reduce averaging times and achieve the required system specifications, including dynamic sensing.This project was carried out under the UCL-Cambridge Centre for Doctoral Training in Photonic Systems Development, with funding from EPSRC (EP/G037256/1) gratefully acknowledged. The support from the Cambridge Centre for Smart Infrastructure and Construction is also acknowledged. Special acknowledgement to Prof Aldo Minardo for his profound advice and discussion on the BOTDA model.This is the final version of the article. It first appeared from Massey University Press via http://www.s2is.org/Issues/v8/n3/papers/paper8.pd

    Fast and Uniform Optically-Switched Data Centre Networks Enabled by Amplitude Caching

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    We propose amplitude caching to optically equalise burst mode traffic without delay stages. Through a fast, optically-switched system prototype, we demonstrate burst-mode penalties can be mitigated to within 0.4 dB at the KR4 HD-FEC level

    Pressure-induced collapse of spin-orbital Mott state in the hyperhoneycomb iridate β\beta-Li2_2IrO3_3

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    Hyperhoneycomb iridate β\beta-Li2_2IrO3_3 is a three-dimensional analogue of two-dimensional honeycomb iridates, such as α\alpha-Li2_2IrO3_3, which recently appeared as another playground for the physics of Kitaev-type spin liquid. β\beta-Li2_2IrO3_3 shows a non-collinear spiral ordering of spin-orbital-entangled JeffJ_{\rm eff} = 1/2 moments at low temperature, which is known to be suppressed under a pressure of \sim2 GPa. With further increase of pressure, a structural transition is observed at PSP_{\rm S} \sim 4 GPa at room temperature. Using the neutron powder diffraction technique, the crystal structure in the high-pressure phase of β\beta-Li2_2IrO3_3 above PSP_{\rm S} was refined, which indicates the formation of Ir2_2 dimers on the zig-zag chains, with the Ir-Ir distance even shorter than that of metallic Ir. We argue that the strong dimerization stabilizes the bonding molecular orbital state comprising the two local dzxd_{zx}-orbitals on the Ir-O2_2-Ir bond plane, which conflicts with the equal superposition of dxyd_{xy}-, dyzd_{yz}- and dzxd_{zx}- orbitals in the JeffJ_{\rm eff} = 1/2 wave function produced by strong spin-orbit coupling. The results of resonant inelastic x-ray scattering (RIXS) measurements and the electronic structure calculations are fully consistent with the collapse of the JeffJ_{\rm eff} = 1/2 state. A subtle competition of various electronic phases is universal in honeycomb-based Kitaev materials

    Web-based guided insulin self-titration in patients with type 2 diabetes: the Di@log study. Design of a cluster randomised controlled trial [TC1316]

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    <p>Abstract</p> <p>Background</p> <p>Many patients with type 2 diabetes (T2DM) are not able to reach the glycaemic target level of HbA1c < 7.0%, and therefore are at increased risk of developing severe complications. Transition to insulin therapy is one of the obstacles in diabetes management, because of barriers of both patient and health care providers. Patient empowerment, a patient-centred approach, is vital for improving diabetes management. We developed a web-based self-management programme for insulin titration in T2DM patients. The aim of our study is to investigate if this internet programme helps to improve glycaemic control more effectively than usual care.</p> <p>Methods/Design</p> <p>T2DM patients (n = 248), aged 35–75 years, with an HbA1c ≥ 7.0%, eligible for treatment with insulin and able to use the internet will be selected from general practices in two different regions in the Netherlands. Cluster randomisation will be performed at the level of general practices. Patients in the intervention group will use a self-developed internet programme to assist them in self-titrating insulin. The control group will receive usual care.</p> <p>Primary outcome is the difference in change in HbA1c between intervention and control group. Secondary outcome measures are quality of life, treatment satisfaction, diabetes self-efficacy and frequency of hypoglycaemic episodes. Results will be analysed according to the intention-to-treat principle.</p> <p>Discussion</p> <p>An internet intervention supporting self-titration of insulin therapy in T2DM patients is an innovative patient-centred intervention. The programme provides guided self-monitoring and evaluation of health and self-care behaviours through tailored feedback on input of glucose values. This is expected to result in a better performance of self-titration of insulin and consequently in the improvement of glycaemic control. The patient will be enabled to 'discover and use his or her own ability to gain mastery over his/her diabetes' and therefore patient empowerment will increase. Based on the self-regulation theory of Leventhal, we hypothesize that additional benefits will be achieved in terms of increases in treatment satisfaction, quality of life and self-efficacy.</p> <p>Trial registration</p> <p>Dutch Trial Register TC1316.</p

    Loss of Kruppel-like factor 3 (KLF3/BKLF) leads to upregulation of the insulin-sensitizing factor adipolin (FAM132A/CTRP12/C1qdc2)

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    Krüppel-like factor 3 (KLF3) is a transcriptional regulator that we have shown to be involved in the regulation of adipogenesis in vitro. Here, we report that KLF3-null mice are lean and protected from diet-induced obesity and glucose intolerance. On a chow diet, plasma levels of leptin are decreased, and adiponectin is increased. Despite significant reductions in body weight and adiposity, wild-type and knockout animals show equivalent energy intake, expenditure, and excretion. To investigate the molecular events underlying these observations, we used microarray analysis to compare gene expression in Klf3(+/+) and Klf3(-/-) tissues. We found that mRNA expression of Fam132a, which encodes a newly identified insulin-sensitizing adipokine, adipolin, is significantly upregulated in the absence of KLF3. We confirmed that KLF3 binds the Fam132a promoter in vitro and in vivo and that this leads to repression of promoter activity. Further, plasma adipolin levels were significantly increased in Klf3(-/-) mice compared with wild-type littermates. Boosting levels of adipolin via targeting of KLF3 offers a novel potential therapeutic strategy for the treatment of insulin resistance

    Can programme theory be used as a 'translational tool’ to optimise health service delivery in a national early years’ initiative in Scotland: a case study

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    Background Theory-based evaluation (TBE) approaches are heralded as supporting formative evaluation by facilitating increased use of evaluative findings to guide programme improvement. It is essential that learning from programme implementation is better used to improve delivery and to inform other initiatives, if interventions are to be as effective as they have the potential to be. Nonetheless, few studies describe formative feedback methods, or report direct instrumental use of findings resulting from TBE. This paper uses the case of Scotland’s, National Health Service, early years’, oral health improvement initiative (Childsmile) to describe the use of TBE as a framework for providing feedback on delivery to programme staff and to assess its impact on programmatic action.&lt;p&gt;&lt;/p&gt; Methods In-depth, semi-structured interviews and focus groups with key stakeholders explored perceived deviations between the Childsmile programme 'as delivered’ and its Programme Theory (PT). The data was thematically analysed using constant comparative methods. Findings were shared with key programme stakeholders and discussions around likely impact and necessary actions were facilitated by the authors. Documentary review and ongoing observations of programme meetings were undertaken to assess the extent to which learning was acted upon.&lt;p&gt;&lt;/p&gt; Results On the whole, the activities documented in Childsmile’s PT were implemented as intended. This paper purposefully focuses on those activities where variation in delivery was evident. Differences resulted from the stage of roll-out reached and the flexibility given to individual NHS boards to tailor local implementation. Some adaptations were thought to have diverged from the central features of Childsmile’s PT, to the extent that there was a risk to achieving outcomes. The methods employed prompted national service improvement action, and proposals for local action by individual NHS boards to address this.&lt;p&gt;&lt;/p&gt; Conclusions The TBE approach provided a platform, to direct attention to areas of risk within a national health initiative, and to agree which intervention components were 'core’ to its hypothesised success. The study demonstrates that PT can be used as a 'translational tool’ to facilitate instrumental use of evaluative findings to optimise implementation within a complex health improvement programme.&lt;p&gt;&lt;/p&gt

    Health care professionals meeting with individuals with Type 2 diabetes and obesity: Balancing coaching and caution

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    The burden of diabetes and obesity is increasing worldwide, indicating a need to find the best standard for diabetes care. The aim of this study was to generate a theory grounded in empirical data derived from a deeper understanding of health care professionals’ main concerns when they consult with individuals with diabetes and obesity and how they handle these concerns. Tape-recorded interviews were conducted with seven groups and three individual members of a diabetes team in an area of western Sweden. The grounded theory (GT) method was used to analyse the transcribed interviews. A core category, labelled Balancing coaching and caution and three categories (Coaching and supporting, Ambivalence and uncertainty, and Adjusting intentions) emerged. The core category and the three categories formed a substantive theory that explained and illuminated how health care professionals manage their main concern; their ambition to give professional individualised care; and find the right strategy for each individual with diabetes and obesity. The theory generated by this study can improve our understanding of how a lack of workable strategies limits caregivers’ abilities to reach their goals. It also helps identify the factors that contribute to the complexity of meetings between caregivers and individuals with diabetes
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