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| 2. |
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- 2017
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Ingår i: Physical Review D. - 2470-0010 .- 2470-0029. ; 96:2
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Tidskriftsartikel (refereegranskat)
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| 3. |
- Adrian-Martinez, S., et al.
(författare)
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A first search for coincident gravitational waves and high energy neutrinos using LIGO, Virgo and ANTARES data from 2007
- 2013
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Ingår i: Journal of Cosmology and Astroparticle Physics. - : IOP Publishing. - 1475-7516. ; :6
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Tidskriftsartikel (refereegranskat)abstract
- We present the results of the first search for gravitational wave bursts associated with high energy neutrinos. Together, these messengers could reveal new, hidden sources that are not observed by conventional photon astronomy, particularly at high energy. Our search uses neutrinos detected by the underwater neutrino telescope ANTARES in its 5 line configuration during the period January - September 2007, which coincided with the fifth and first science runs of LIGO and Virgo, respectively. The LIGO-Virgo data were analysed for candidate gravitational-wave signals coincident in time and direction with the neutrino events. No significant coincident events were observed. We place limits on the density of joint high energy neutrino - gravitational wave emission events in the local universe, and compare them with densities of merger and core-collapse events.
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| 4. |
- Evans, P. A., et al.
(författare)
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Swift Follow-up Observations of Candidate Gravitational-wave Transient Events
- 2012
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Ingår i: The Astrophysical Journal Supplement Series. - : American Astronomical Society. - 0067-0049 .- 1538-4365. ; 203:2
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Tidskriftsartikel (refereegranskat)abstract
- We present the first multi-wavelength follow-up observations of two candidate gravitational-wave (GW) transient events recorded by LIGO and Virgo in their 2009-2010 science run. The events were selected with low latency by the network of GW detectors (within less than 10 minutes) and their candidate sky locations were observed by the Swift observatory (within 12 hr). Image transient detection was used to analyze the collected electromagnetic data, which were found to be consistent with background. Off-line analysis of the GW data alone has also established that the selected GW events show no evidence of an astrophysical origin; one of them is consistent with background and the other one was a test, part of a "blind injection challenge." With this work we demonstrate the feasibility of rapid follow-ups of GW transients and establish the sensitivity improvement joint electromagnetic and GW observations could bring. This is a first step toward an electromagnetic follow-up program in the regime of routine detections with the advanced GW instruments expected within this decade. In that regime, multi-wavelength observations will play a significant role in completing the astrophysical identification of GW sources. We present the methods and results from this first combined analysis and discuss its implications in terms of sensitivity for the present and future instruments.
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| 5. |
- Aasi, J., et al.
(författare)
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Parameter estimation for compact binary coalescence signals with the first generation gravitational-wave detector network
- 2013
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Ingår i: Physical Review D (Particles, Fields, Gravitation and Cosmology). - 1550-2368. ; 88:6
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Tidskriftsartikel (refereegranskat)abstract
- Compact binary systems with neutron stars or black holes are one of the most promising sources for ground-based gravitational-wave detectors. Gravitational radiation encodes rich information about source physics; thus parameter estimation and model selection are crucial analysis steps for any detection candidate events. Detailed models of the anticipated waveforms enable inference on several parameters, such as component masses, spins, sky location and distance, that are essential for new astrophysical studies of these sources. However, accurate measurements of these parameters and discrimination of models describing the underlying physics are complicated by artifacts in the data, uncertainties in the waveform models and in the calibration of the detectors. Here we report such measurements on a selection of simulated signals added either in hardware or software to the data collected by the two LIGO instruments and the Virgo detector during their most recent joint science run, including a "blind injection'' where the signal was not initially revealed to the collaboration. We exemplify the ability to extract information about the source physics on signals that cover the neutron-star and black-hole binary parameter space over the component mass range 1M(circle dot)-25M(circle dot) and the full range of spin parameters. The cases reported in this study provide a snapshot of the status of parameter estimation in preparation for the operation of advanced detectors.
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| 6. |
- Aasi, J., et al.
(författare)
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Search for gravitational waves from binary black hole inspiral, merger, and ringdown in LIGO-Virgo data from 2009-2010
- 2013
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Ingår i: Physical Review D (Particles, Fields, Gravitation and Cosmology). - 1550-2368. ; 87:2
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Tidskriftsartikel (refereegranskat)abstract
- We report a search for gravitational waves from the inspiral, merger and ringdown of binary black holes (BBH) with total mass between 25 and 100 solar masses, in data taken at the LIGO and Virgo observatories between July 7, 2009 and October 20, 2010. The maximum sensitive distance of the detectors over this period for a (20, 20)M-circle dot coalescence was 300 Mpc. No gravitational wave signals were found. We thus report upper limits on the astrophysical coalescence rates of BBH as a function of the component masses for nonspinning components, and also evaluate the dependence of the search sensitivity on component spins aligned with the orbital angular momentum. We find an upper limit at 90% confidence on the coalescence rate of BBH with nonspinning components of mass between 19 and 28M(circle dot) of 3:3 x 10(-7) mergers Mpc(-3) yr(-1).
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| 7. |
- Aasi, J., et al.
(författare)
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The characterization of Virgo data and its impact on gravitational-wave searches
- 2012
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Ingår i: Classical and Quantum Gravity. - : IOP Publishing. - 1361-6382 .- 0264-9381. ; 29:15
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Tidskriftsartikel (refereegranskat)abstract
- Between 2007 and 2010 Virgo collected data in coincidence with the LIGO and GEO gravitational-wave (GW) detectors. These data have been searched for GWs emitted by cataclysmic phenomena in the universe, by non-axisymmetric rotating neutron stars or from a stochastic background in the frequency band of the detectors. The sensitivity of GW searches is limited by noise produced by the detector or its environment. It is therefore crucial to characterize the various noise sources in a GW detector. This paper reviews the Virgo detector noise sources, noise propagation, and conversion mechanisms which were identified in the three first Virgo observing runs. In many cases, these investigations allowed us to mitigate noise sources in the detector, or to selectively flag noise events and discard them from the data. We present examples from the joint LIGO-GEO-Virgo GW searches to show how well noise transients and narrow spectral lines have been identified and excluded from the Virgo data. We also discuss how detector characterization can improve the astrophysical reach of GW searches.
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| 8. |
- Aasi, J., et al.
(författare)
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Einstein@Home all-sky search for periodic gravitational waves in LIGO S5 data
- 2013
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Ingår i: Physical Review D (Particles, Fields, Gravitation and Cosmology). - 1550-2368. ; 87:4
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents results of an all-sky search for periodic gravitational waves in the frequency range [50, 1190] Hz and with frequency derivative range of similar to[-20, 1.1] x 10(-10) Hz s(-1) for the fifth LIGO science run (S5). The search uses a noncoherent Hough-transform method to combine the information from coherent searches on time scales of about one day. Because these searches are very computationally intensive, they have been carried out with the Einstein@Home volunteer distributed computing project. Postprocessing identifies eight candidate signals; deeper follow-up studies rule them out. Hence, since no gravitational wave signals have been found, we report upper limits on the intrinsic gravitational wave strain amplitude h(0). For example, in the 0.5 Hz-wide band at 152.5 Hz, we can exclude the presence of signals with h(0) greater than 7.6 x 10(-25) at a 90% confidence level. This search is about a factor 3 more sensitive than the previous Einstein@Home search of early S5 LIGO data.
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| 9. |
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| 10. |
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| 11. |
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| 12. |
- Benisty, H., et al.
(författare)
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Low-loss photonic-crystal and monolithic InP integration : Bands, bends, lasers, filters
- 2004
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Ingår i: Photonic Crystal Materials and Devices II. - : SPIE - International Society for Optical Engineering. - 0819452688 ; , s. 119-128
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Konferensbidrag (refereegranskat)abstract
- Practical realizations of 2D (planar) photonics crystal (PhC) are either on a membrane or etched through a conventional heterostructure. While fascinating objects can emerge from the first approach, only the latter approach lends itself to a progressive integration of more compact PhC's towards monolithic PICs based on InP. We describe in this talk the various aspects from technology to functions and devices, as emerged from the European collaboration "PCIC". The main technology tour de force is deep-etching with aspect ratio of about 10 and vertical sidewall, achieved by three techniques (CAIBE, ICP-RIE, ECR-RIE). The basic functions explored are bends, splitters/combiners, mirrors, tapers, and the devices are filters and lasers. At the end of the talk, I will emphasize some positive aspects of "broad" multimode PhC waveguides, in view of compact add-drop filtering action, notably.
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| 13. |
- Benisty, H., et al.
(författare)
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Models and measurements for the transmission of submicron-width waveguide bends defined in two-dimensional photonic crystals
- 2002
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Ingår i: IEEE Journal of Quantum Electronics. - 0018-9197 .- 1558-1713. ; 38:7, s. 770-785
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Tidskriftsartikel (refereegranskat)abstract
- One of the essential building-blocks of miniature photonic crystal (PC)-based photonic integrated circuits (PICs) is the sharp bend. Our group has focused on the 2-D photonic crystal based on a triangular lattice of holes perforating a standard heterostructure. The latter, GaAlAs-based or InP-based, is vertically a monomode waveguide. We consider essentially one or two 60 bends defined by one to five missing rows, spanning both cases of monomode and multimode channel waveguides. From intensive modeling and various experimental measurements (both on GaAs and InP), we point out the origin of the present level of bend insertion losses and discuss the merits of the many roads open for improved design.
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| 14. |
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| 15. |
- Ferrini, R., et al.
(författare)
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Optical study of two-dimensional InP-based photonic crystals by internal light source technique
- 2002
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Ingår i: IEEE Journal of Quantum Electronics. - 0018-9197 .- 1558-1713. ; 38:7, s. 786-799
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Tidskriftsartikel (refereegranskat)abstract
- We present the first optical study of 2-D photonic crystals (PCs) deeply etched in an InP/GaInAsP step-index waveguide. Following the same internal light source approach proposed by Labilloy and coworkers for the investigation of GaAs-based 2-D PCs, transmission measurements through simple PC slabs and 1-D Fabry-Perot (FP) cavities between PC mirrors were performed. Details are given on the experimental setup which has been implemented with respect to the original scheme and adapted to InP-based systems working at 1.5-mum. 2-D plane-wave expansion and finite difference time-domain (FDTD) methods are used to fit the experimental data. Out-of-plane losses were evaluated according to a recently introduced phenomenological model. In spite of the complex hole morphology in the measured samples, preliminary results are presented which indicate the possibility of separating different loss contributions from finite etch depth and hole shape. As for 1-D cavities, both FDTD and classical theory for planar resonators are applied in order to deduce the optical properties of the PC mirrors. The origin of an anomalously high transmission observed inside the stopgap is discussed and arguments are given to demonstrate the need for further modeling efforts when working in the bandgap regime.
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| 16. |
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| 17. |
- Anand, Srinivasan, et al.
(författare)
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Towards realization of high quality 2D-photonic crystals in InP/GaInAsP/InP
- 2004
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Ingår i: 2004 International Conference on Indium Phosphide and Related Materials, Conference Proceedings. - 0780385950 ; , s. 311-313
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Konferensbidrag (refereegranskat)abstract
- Two-dimensional photonic crystals (PhCs) were etched into InP/GaInAsP/InP planar waveguides using chlorine based chemical assisted ion beam etching (CAIBE). Etching mechanisms and process parameters crucial for high quality PhC definition are discussed, with special attention to the lag-effect. The processed PhCs were optically characterized by measuring transmission through simple slabs and one-dimensional cavities. The optical properties inside the photonic bandgap are much better compared to both previously reported CAME results and results obtained with other etching methods. In particular, we measured a record quality factor of 310 for one-dimensional cavities fabricated in this material system.
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| 18. |
- Dal Canto, E, et al.
(författare)
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Diabetes as a cardiovascular risk factor: An overview of global trends of macro and micro vascular complications
- 2019
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Ingår i: European journal of preventive cardiology. - : Oxford University Press (OUP). - 2047-4881 .- 2047-4873. ; 26:2_SUPPL2_suppl, s. 25-32
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Tidskriftsartikel (refereegranskat)abstract
- The global prevalence of diabetes is predicted to increase dramatically in the coming decades as the population grows and ages, in parallel with the rising burden of overweight and obesity, in both developed and developing countries. Cardiovascular disease represents the principal cause of death and morbidity among people with diabetes, especially in those with type 2 diabetes mellitus. Adults with diabetes have 2–4 times increased cardiovascular risk compared with adults without diabetes, and the risk rises with worsening glycaemic control. Diabetes has been associated with 75% increase in mortality rate in adults, and cardiovascular disease accounts for a large part of the excess mortality. Diabetes-related macrovascular and microvascular complications, including coronary heart disease, cerebrovascular disease, heart failure, peripheral vascular disease, chronic renal disease, diabetic retinopathy and cardiovascular autonomic neuropathy are responsible for the impaired quality of life, disability and premature death associated with diabetes. Given the substantial clinical impact of diabetes as a cardiovascular risk factor, there has been a growing focus on diabetes-related complications. While some population-based studies suggest that the epidemiology of such complications is changing and that rates of all-cause and cardiovascular mortality among individuals with diabetes are decreasing in high-income countries, the economic and social burden of diabetes is expected to rise due to changing demographics and lifestyle especially in middle- and low-income countries. In this review we outline data from population-based studies on recent and long-term trends in diabetes-related complications.
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| 19. |
- Ferrini, M, et al.
(författare)
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Heart failure and its complications in patients with diabetes: Mounting evidence for a growing burden
- 2019
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Ingår i: European journal of preventive cardiology. - : Oxford University Press (OUP). - 2047-4881 .- 2047-4873. ; 26:2_SUPPL2_suppl, s. 106-113
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Tidskriftsartikel (refereegranskat)abstract
- Heart failure (HF) is one of the major challenges in the management of diabetes patients. Among subjects with diabetes, up to 20% could have HF. Conversely, diabetes prevalence in HF patients varies greatly from more than 10% up to 50%. When it is present, the risk of mortality and rehospitalization increases substantially. In addition, current evidence points to an increased risk of atrial fibrillation and sudden cardiac death in patients with diabetes. The inter-relation between diabetes cardiomyopathy, left ventricular hypertrophy, coronary artery disease and renal dysfunction indicates complex and intricate pathways. Despite the great value of clinical assessment and echocardiography, there is insufficient data to suggest systematic screening for HF in asymptomatic patients with diabetes. There is little evidence to indicate that improved glycaemic control improves HF outcome in this population. In the case of established HF, the general guidelines apply in diabetes patients. However, recent advances concerning glucose-lowering treatment in patients with cardiovascular disease suggest that the choice of glucose-lowering agent is of crucial interest and should be based on the patient’s phenotype. New drug classes, such as SGLT2 inhibitors, seem to be of particular benefit in these patients. In the future, new personalized strategies should aim at not only good control of the glycaemic level but also the reduction and possibly the prevention of HF onset.
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| 20. |
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| 21. |
- Martz, J., et al.
(författare)
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Liquid crystal infiltration of InP-based planar photonic crystals
- 2006
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 99:10
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Tidskriftsartikel (refereegranskat)abstract
- A procedure for the infiltration of planar photonic crystals (PhCs) with liquid crystals (LCs) is presented. InP-based PhCs are infiltrated with the nematic LC-K15 in a specially designed high-vacuum chamber. The infiltration technique is validated and systematically characterized by measuring the transmission through the infiltrated PhCs at different temperatures and for different polarizations. The reproducibility and reliability of our procedure are demonstrated and a high filling efficiency is obtained.
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| 22. |
- Moosburger, J., et al.
(författare)
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Nanofabrication of high quality photonic crystals for integrated optics circuits
- 2002
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Ingår i: Nanotechnology. - : IOP Publishing. - 0957-4484 .- 1361-6528. ; 13:3, s. 341-345
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Tidskriftsartikel (refereegranskat)abstract
- In this paper we report on the fabrication and characterization of two-dimensional photonic crystals. They are realized as a hexagonal array of air holes etched in GaAs or InP based slab waveguide heterostructures. The fabrication steps are discussed, with a focus on the development of suitable dry etching processes. Holes with a depth of I mum on GaAs and 4 Mm on InP were fabricated, which results in a good overlap of the guided mode with the photonic crystal patterns and low losses. The optical quality of the structures is assessed by transmission spectroscopy of photonic crystal blocks and photonic crystal-based waveguides.
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| 23. |
- Prattichizzo, F, et al.
(författare)
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Glucose-lowering therapies in patients with type 2 diabetes and cardiovascular diseases
- 2019
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Ingår i: European journal of preventive cardiology. - : Oxford University Press (OUP). - 2047-4881 .- 2047-4873. ; 26:2_SUPPL2_suppl, s. 73-80
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Tidskriftsartikel (refereegranskat)abstract
- Type 2 diabetes mellitus is a major risk factor for developing cardiovascular disease, and many patients with diabetes have prevalent cardiovascular complications. Recent cardiovascular outcome clinical trials suggest that certain new glucose-lowering drugs are accompanied by additional cardioprotective properties. Indeed, selected glucagon-like peptide-1 receptor agonists have a proved cardiovascular benefit in terms of a reduced incidence of ischaemic events, while sodium/glucose co-transporter-2 inhibitors have also shown significant protection, with a striking effect on heart failure and renal endpoints. These findings have been integrated in recent guidelines which now recommend prescribing (when initial metformin monotherapy fails) a glucagon-like peptide-1 receptor agonist or a sodium/glucose co-transporter-2 inhibitor with clinical trial-confirmed benefit in patients with diabetes and atherosclerotic cardiovascular disease, and a sodium/glucose co-transporter-2 inhibitor in such patients with heart failure or chronic kidney disease at initial stages. Furthermore, the new 2019 European Society of Cardiology guidelines in collaboration with the European Association for the Study of Diabetes recommend a glucagon-like peptide-1 receptor agonist or a sodium/glucose co-transporter-2 inhibitor in treatment-naive patients with type 2 diabetes mellitus with pre-existing cardiovascular disease or at high cardiovascular risk. Future research will disentangle the mechanisms underpinning these beneficial effects and will also establish to what extent these results are generalisable to the whole diabetes population. In the meantime, available evidence should prompt a wide diffusion of these two classes of drugs among patients with diabetes and cardiovascular disease. Here, we briefly summarise recent findings emerging from cardiovascular outcome clinical trials, discuss their impact on treatment algorithms and propose new possible approaches to improve our knowledge further regarding the cardiovascular effect of glucose-lowering medications.
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| 24. |
- Weatherall, Pauline, et al.
(författare)
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A new digital bathymetric model of the world's oceans
- 2015
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Ingår i: Earth and Space Science. - 2333-5084. ; 2:8, s. 331-345
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Tidskriftsartikel (refereegranskat)abstract
- General Bathymetric Chart of the Oceans (GEBCO) has released the GEBCO_2014 grid, a new digital bathymetric model of the world ocean floor merged with land topography from publicly available digital elevation models. GEBCO_2014 has a grid spacing of 30 arc sec and updates the 2010 release (GEBCO_08) by incorporating new versions of regional bathymetric compilations from the International Bathymetric Chart of the Arctic Ocean, the International Bathymetric Chart of the Southern Ocean, the Baltic Sea Bathymetry Database, and data from the European Marine Observation and Data network bathymetry portal, among other data sources. Approximately 33% of ocean grid cells (not area) have been updated in GEBCO_2014 from the previous version, including both new interpolated depth values and added soundings. These updates include large amounts of multibeam data collected using modern equipment and navigation techniques, improving portrayed details of the world ocean floor. Of all nonland grid cells in GEBCO_2014, approximately 18% are based on bathymetric control data, i.e., primarily multibeam and single-beam soundings or preprepared grids which may contain some interpolated values. The GEBCO_2014 grid has a mean and median depth of 3897 m and 3441 m, respectively. Hypsometric analysis reveals that 50% of the Earth's surface is composed of seafloor located 3200 m below mean sea level and that ~900 ship years of surveying would be needed to obtain complete multibeam coverage of the world's oceans.
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| 25. |
- Wild, B., et al.
(författare)
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Temperature tuning of the optical properties of planar photonic crystal microcavities
- 2004
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Ingår i: Proc SPIE Int Soc Opt Eng. - : SPIE. ; , s. 311-317
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Konferensbidrag (refereegranskat)abstract
- We report on the temperature tuning of the optical properties of planar Photonic Crystal (PhC) microcavities. Studies were made on one and two dimensional PhCs that were etched in InP and GaAs vertical waveguides. Two dimensional (hexagonal) and one-dimensional (Fabry-Pérot) cavities were optically investigated by an internal light source technique. The samples were mounted on a Peltier-stage which allowed temperature variation from T = 20 °C up to T = 76 °C. A linear dependence of the resonance wavelengths with respect to temperature is observed. A gradient of dλ/dT = 0.09 nm/°C and 0.1 nm/°C for the GaAs and InP based cavities was observed, respectively. These results are in agreement with the theoretical calculations based on the thermal dependence of the refractive index of the PhC semiconductor component.
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