Photon energy lifter

We propose a time-dependent photonic structure, in which the carrier frequency of an optical pulse is shifted without changing its shape. The efficiency of the device takes advantage of slow group velocities of light attainable in periodic photonic structures. The frequency shifting effect is quantitatively studied by means of Finite Difference Time Domain simulations for realistic systems with optical parameters of conventional silicon technology.Comment: 4 pages 5 figure

Photon recycling in Fabry-Perot micro-cavities based on Si3_3N4_4 waveguides

We present a numerical analysis and preliminary experimental results on one-dimensional Fabry-Perot micro-cavities in Si$_3$N$_4$ waveguides. The Fabry-Perot micro-cavities are formed by two distributed Bragg reflectors separated by a straight portion of waveguide. The Bragg reflectors are composed by a few air slits produced within the Si$_3$N$_4$ waveguides. In order to increase the quality factor of the micro-cavities, we have minimized, with a multiparametric optimization tool, the insertion loss of the reflectors by varying the length of their first periods (those facing the cavity). To explain the simulation results the coupling of the fundamental waveguide mode with radiative modes in the Fabry-Perot micro-cavities is needed. This effect is described as a recycling of radiative modes in the waveguide. To support the modelling, preliminary experimental results of micro-cavities in Si$_3$N$_4$ waveguides realized with Focused Ion Beam technique are reported.Comment: 5 pages, 5 figure

Can Noncommunicable Diseases Be Prevented? Lessons from Studies of Populations and Individuals

http://dx.doi.org/10.1126/science.122700

Tailoring correlations of the local density of states in disordered photonic materials

We present experimental evidence for the different mechanisms driving the fluctuations of the local density of states (LDOS) in disordered photonic systems. We establish a clear link between the microscopic structure of the material and the frequency correlation function of LDOS accessed by a near-field hyperspectral imaging technique. We show, in particular, that short- and long-range frequency correlations of LDOS are controlled by different physical processes (multiple or single scattering processes, respectively) that can be---to some extent---manipulated independently. We also demonstrate that the single scattering contribution to LDOS fluctuations is sensitive to subwavelength features of the material and, in particular, to the correlation length of its dielectric function. Our work paves a way towards a complete control of statistical properties of disordered photonic systems, allowing for designing materials with predefined correlations of LDOS.Comment: 5+9 pages, 5+6 figures. Fixed confusion of references between the main text and the supplemental material in version

Body mass index, abdominal fatness, fat mass and the risk of atrial fibrillation: a systematic review and dose–response meta-analysis of prospective studies

Different adiposity measures have been associ- ated with increased risk of atrial fibrillation, however, results have previously only been summarized for BMI. We therefore conducted a systematic review and meta- analysis of prospective studies to clarify the association between different adiposity measures and risk of atrial fibrillation. PubMed and Embase databases were searched up to October 24th 2016. Summary relative risks (RRs) were calculated using random effects models. Twenty-nine unique prospective studies (32 publications) were included. Twenty-five studies (83,006 cases, 2,405,381 participants) were included in the analysis of BMI and atrial fibrillation. The summary RR was 1.28 (95% confidence interval: 1.20–1.38, I 2 = 97%) per 5 unit increment in BMI, 1.18 (95% CI: 1.12–1.25, I 2 = 73%, n = 5) and 1.32 (95% CI: 1.16–1.51, I 2 = 91%, n = 3) per 10 cm increase in waist and hip circumference, respectively, 1.09 (95% CI: 1.02–1.16, I 2 = 44%, n = 4) per 0.1 unit increase in waist- to-hip ratio, 1.09 (95% CI: 1.02–1.16, I 2 = 94%, n = 4) per 5 kg increase in fat mass, 1.10 (95% CI: 0.92–1.33, I 2 = 90%, n = 3) per 10% increase in fat percentage, 1.10 (95% CI: 1.08–1.13, I 2 = 74%, n = 10) per 5 kg increase in weight, and 1.08 (95% CI: 0.97–1.19, I 2 = 86%, n = 2) per 5% increase in weight gain. The association between BMI and atrial fibrillation was non- linear, p nonlinearity \ 0.0001, with a stronger association at higher BMI levels, however, increased risk was observed even at a BMI of 22–24 compared to 20. In conclusion, general and abdominal adiposity and higher body fat mass increase the risk of atrial fibrillation

Band gap characterization and slow light effects in one dimensional photonic crystals based on silicon slot-waveguides.

We investigate the photonic properties of one dimensional photonic crystals realized on Silicon On Insulator channel slot-waveguide to engineer slow light effects. Various geometries of the photonic pattern have been characterized and their photonic band-gap structure analyzed. The optimal geometry has been further used to realize a coupled resonator optical waveguide (CROW). A first optimization of these CROW devices shows a group velocity of more than c/10 at 1.55 mum. Full three dimensional calculations based on the planar wave expansion method have been used to compute the band diagram while full three dimensional calculations based on finite difference time domain methods have been used to study light propagation

full model multiaxial fatigue life calculations with different criteria

Abstract Fatigue design of structural components under multiaxial loading often relies on fatigue life calculations based on a post-processing of the full-field elastic stress/strain maps obtained from finite element (FE) analysis. In the present article, a post-processing tool is adopted to compute the fatigue life of a structural component, and multiaxial fatigue assessment is carried out by considering different criteria such as that of Smith-Watson-Topper and of Fatemi-Socie. The present paper focuses on a specific structural component related to a quarter-turn heavy-duty valve actuator, called scotch yoke, commonly used in many application sectors such as oil & gas, power and chemical industries. The fatigue assessment of the component is carried out by employing a full-model FE analysis, considering fillet-welded joints exposed to in-phase constant amplitude cyclic bending-torsion fatigue load with load ratio R=-1, with applied maximum load according to EN 15714-3, which is the standard in the valve actuator sector. The elastic stress/strain field extracted from the FE model is used to perform the fatigue assessment of the fillet-welded joints, where the potential fatigue crack initiation points (weld toe and weld root) are described by adopting an effective radius at the weld notches

Characterising extant technology related barriers & enablers for streamlined delivery of BP@home in North Central London: Report for NCL LTC Clinical Network

Report objectives: This report summarises the key findings of a place-based evaluation to identify barriers and enablers to the streamlined use of digital tools to support successful implementation of BP@home in North Central London (NCL). Specifically, we characterised the IT landscape in NCL, investigated the views and experiences of HCPs regarding the use of place-based IT solutions and processes, and synthesised a list of evidence-based recommendations for the consideration of NCL leadership team. Methods: We used a mixed methods research approach and six phases of investigation to address these aims, including desktop research, personal interviews and focus groups, action research, data analysis, synthesis and reporting. Results: The evaluation showed that there was a lack of standardisation across IT systems, internal processes and templates in PCNs in NCL, leading to challenges in implementing and using digital tools to support BP@home. These challenges were not unique to NCL. AccurX and the locally created NCL template are the most widely used IT tools to support the program in NCL. Other digital platforms being tested in NCL include Suvera, each with unique strengths and weaknesses. Other digital tools, such as Omron Connect, could be considered to support management of hypertension and other chronic conditions. HCPs faced challenges with patient engagement, data quality, IT system integration and resource allocation, but generally felt that the current approach works. Basic requirements for the use and adoption of IT tools and systems include adequate resources, stakeholder engagement, user-friendly interfaces, and interoperability between different systems. We proposed 16 actionable insights and recommendations that could be implemented to help improve the delivery of BP@home in NCL. These include standardising IT systems, improving patient engagement, providing adequate training and support, and promoting the benefits of remote monitoring. Conclusion: On balance, we recommend that NCL continues to deliver BP@home using the current standard IT offer that facilitates asynchronous engagement with patients (i.e., AccurX). Embedding a quality improvement approach to identify mechanisms to continually improve the BP@home offer in NCL is recommended. Clinical leadership could also review the evaluation findings of alternative tools currently being tested locally (e.g., pilot using Suvera across one PCN) to drive evidence-based commissioning decision as the BP@home initiative becomes even more embedded in routine general practice