567 research outputs found

    Comparison of DVB-T Passive Radar Simulated and Measured Bistatic RCS Values for a Pilatus PC-12 Aircraft

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    Passive radar is a technology that has huge potential for airspace monitoring, taking advantage of existing transmissions. However, to predict whether particular targets can be measured in a particular scenario, it is necessary to be able to model the received signal. In this paper, we present the results of a campaign in which a Pilatus PC-12 single-engine aircraft was measured with a passive radar system relying on DVB-T transmission from a single transmitter. We then present our work to simulate the bistatic RCS of the aircraft along its flight track, using both the method of moments and the shooting and bouncing ray solvers, assess the uncertainty in the simulations, and compare against the measurements. We find that our simulated RCS values are useful in predicting whether or not detection occurs. However, we see poor agreement between simulated and measured RCS values where measurements are available, which we attribute primarily to the difficulties in extracting RCS measurements from the data and to unmodeled transmission and received path effects

    Frustrated H-Induced Instability of Mo(110)

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    Using helium atom scattering Hulpke and L"udecke recently observed a giant phonon anomaly for the hydrogen covered W(110) and Mo(110) surfaces. An explanation which is able to account for this and other experiments is still lacking. Below we present density-functional theory calculations of the atomic and electronic structure of the clean and hydrogen-covered Mo(110) surfaces. For the full adsorbate monolayer the calculations provide evidence for a strong Fermi surface nesting instability. This explains the observed anomalies and resolves the apparent inconsistencies of different experiments.Comment: 4 pages, 2 figures, submitted to PR

    Comparison of the New-Generation Self-Expanding NAVITOR Transcatheter Heart Valve with Its Predecessor, the PORTICO, in Severe Native Aortic Valve Stenosis

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    Background Third-generation transcatheter heart valves (THVs) are designed to improve outcomes. Data on the new intra-annular self-expanding NAVITOR are scarce. Aims The aim of this analysis was to compare outcomes between the PORTICO and the NAVITOR systems. Methods Data from 782 patients with severe native aortic stenosis treated with PORTICO (n = 645) or NAVITOR (n = 137) from 05/2012 to 09/2022 were evaluated. The clinical and hemodynamic outcomes of 276 patients (PORTICO, n = 139; NAVITOR, n = 137) were evaluated according to VARC-3 recommendations. Results Rates of postprocedural more-than-mild paravalvular leakage (PVL) were significantly lower for NAVITOR than for PORTICO (7.2% vs. 1.5%, p = 0.041). In addition, severe bleeding rates (27.3% vs. 13.1%, p = 0.005) and major vascular complications (5.8% vs. 0.7%, p = 0.036) were lower in the NAVITOR group. The mean gradients (7 vs. 8 mmHg, p = 0.121) and calculated aortic valve areas (1.90 cm2 vs. 1.99 cm2, p = 0.235) were comparable. Rates of PPI were similarly high in both groups (15.3 vs. 21.6, p = 0.299). Conclusions The NAVITOR demonstrated favorable in-hospital procedural outcome data, with lower rates of relevant PVL, major vascular complications, and severe bleeding than its predecessor the PORTICO and preserved favorable hemodynamic outcomes

    The STEAMR Instrument: Optical Design, Development & Testing

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    The STEAMR instrument is a Swedish national contribution to the ESA PREMIER mission, which is a candidate for the upcoming Earth Core Explorer mission. The STEAMR instrument is envisaged as a multi-beam limb sounding satellite, which will utilise 14 simultaneously observing beams in two 12 GHz wide bands from 323 to 357 GHz. To maximize spatial sampling in the elevation direction the observing beams have an elliptical geometry, which defines the incoming beams as being astigmatic. In this paper we present an antenna optics scheme which corrects for this inherent astigmatism, thereby ensuring optimum imaging of the incoming to the circularly symmetric receiver feed horns. Furthermore, the design, synthesis and electromagnetic verification of a prototype focal plane array for the STEAMR instrument is also reported

    Procedural Outcomes of a Self-Expanding Transcatheter Heart Valve in Patients with Porcelain Aorta

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    Background: Severe calcification of the ascending aorta increases the peri-operative risk for neurological complications in patients with severe aortic stenosis. Transcatheter aortic valve implantation (TAVI) seems to be an optimal treatment option in these patients. However, the impact of the extent of aortic calcification on procedural and neurological outcomes during TAVI is unclear. Methods: Data from 3010 patients with severe native aortic valve stenosis treated with ACURATE neo/neo2 from May 2012 to July 2022 were evaluated and matched by 2-to-1 nearest-neighbor matching to identify one patient with porcelain aorta (PA) (n = 492) compared with two patients without PA (n = 984). PA was additionally subdivided into circumferential (classic PA) (n = 89; 3.0%) and non-circumferential (partial PA) (n = 403; 13.4%) calcification. We compared outcomes according to VARC-3 criteria among patients with and without PA and identified predictors for occurrence of stroke in the overall population. Results: Technical success (88.5% vs. 87.4%, p = 0.589) and device success at 30 days (82.3% vs. 81.5%, p = 0.755) after transcatheter ACURATE neo/neo2 implantation according to VARC-3 definition was high and did not differ between non-calcified aortas or PA. The rate of in-hospital complications according to VARC-3-definitions was low in both groups. Rates of all stroke (3.2% (n = 31) vs. 2.6% (n = 13), p = 0.705) or transitory ischemic attacks (1.1% vs. 1.2%, p = 1.000) did not differ significantly. Thirty-day all-cause mortality did not differ (3.0% vs. 3.2%, RR 1.1; p = 0.775). Overall device migration/embolization (OR 5.0 [2.10;11.87]), severe bleeding (OR 1.79 [1.11;2.89]), and major structural cardiac complications (OR 3.37 [1.32;8.57]) were identified as independent predictors for in-hospital stroke in a multivariate analysis after implantation of ACURATE neo/neo2. Conclusion: A porcelain aorta does not increase the risk of neurological complications after transfemoral ACURATE neo/neo2 implantation. Based on these findings, transfemoral ACURATE neo/neo2 implantation is safe in these particularly vulnerable patients

    Search for stop and higgsino production using diphoton Higgs boson decays

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    Results are presented of a search for a "natural" supersymmetry scenario with gauge mediated symmetry breaking. It is assumed that only the supersymmetric partners of the top-quark (stop) and the Higgs boson (higgsino) are accessible. Events are examined in which there are two photons forming a Higgs boson candidate, and at least two b-quark jets. In 19.7 inverse femtobarns of proton-proton collision data at sqrt(s) = 8 TeV, recorded in the CMS experiment, no evidence of a signal is found and lower limits at the 95% confidence level are set, excluding the stop mass below 360 to 410 GeV, depending on the higgsino mass

    Differential cross section measurements for the production of a W boson in association with jets in proton–proton collisions at √s = 7 TeV

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    Measurements are reported of differential cross sections for the production of a W boson, which decays into a muon and a neutrino, in association with jets, as a function of several variables, including the transverse momenta (pT) and pseudorapidities of the four leading jets, the scalar sum of jet transverse momenta (HT), and the difference in azimuthal angle between the directions of each jet and the muon. The data sample of pp collisions at a centre-of-mass energy of 7 TeV was collected with the CMS detector at the LHC and corresponds to an integrated luminosity of 5.0 fb[superscript −1]. The measured cross sections are compared to predictions from Monte Carlo generators, MadGraph + pythia and sherpa, and to next-to-leading-order calculations from BlackHat + sherpa. The differential cross sections are found to be in agreement with the predictions, apart from the pT distributions of the leading jets at high pT values, the distributions of the HT at high-HT and low jet multiplicity, and the distribution of the difference in azimuthal angle between the leading jet and the muon at low values.United States. Dept. of EnergyNational Science Foundation (U.S.)Alfred P. Sloan Foundatio

    Penilaian Kinerja Keuangan Koperasi di Kabupaten Pelalawan

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    This paper describe development and financial performance of cooperative in District Pelalawan among 2007 - 2008. Studies on primary and secondary cooperative in 12 sub-districts. Method in this stady use performance measuring of productivity, efficiency, growth, liquidity, and solvability of cooperative. Productivity of cooperative in Pelalawan was highly but efficiency still low. Profit and income were highly, even liquidity of cooperative very high, and solvability was good

    Juxtaposing BTE and ATE – on the role of the European insurance industry in funding civil litigation

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    One of the ways in which legal services are financed, and indeed shaped, is through private insurance arrangement. Two contrasting types of legal expenses insurance contracts (LEI) seem to dominate in Europe: before the event (BTE) and after the event (ATE) legal expenses insurance. Notwithstanding institutional differences between different legal systems, BTE and ATE insurance arrangements may be instrumental if government policy is geared towards strengthening a market-oriented system of financing access to justice for individuals and business. At the same time, emphasizing the role of a private industry as a keeper of the gates to justice raises issues of accountability and transparency, not readily reconcilable with demands of competition. Moreover, multiple actors (clients, lawyers, courts, insurers) are involved, causing behavioural dynamics which are not easily predicted or influenced. Against this background, this paper looks into BTE and ATE arrangements by analysing the particularities of BTE and ATE arrangements currently available in some European jurisdictions and by painting a picture of their respective markets and legal contexts. This allows for some reflection on the performance of BTE and ATE providers as both financiers and keepers. Two issues emerge from the analysis that are worthy of some further reflection. Firstly, there is the problematic long-term sustainability of some ATE products. Secondly, the challenges faced by policymakers that would like to nudge consumers into voluntarily taking out BTE LEI
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