179 research outputs found
Momentum dependent light scattering in insulating cuprates
We investigate the problem of inelastic x-ray scattering in the spin
Heisenberg model on the square lattice. We first derive a momentum dependent
scattering operator for the and polarization geometries. On
the basis of a spin-wave analysis, including magnon-magnon interactions and
exact-diagonalizations, we determine the qualitative shape of the spectra. We
argue that our results may be relevant to help interpret inelastic x-ray
scattering experiments in the antiferromagnetic phase of the cuprates.Comment: 5 pages, 3 figures, to appear in PR
The Impact of an Oxygen Dopant in an ideal Bi-2212 Crystal
Recent scanning tunneling microscopy studies have shown that local nanoscale
pairing inhomogenities are correlated with interstitial oxygen dopants in
Bi-2212. Combining electrostatic and cluster calculations, in this paper the
impact of a dopant on the local Madelung and charge transfer energies, magnetic
exchange J, Zhang-Rice mobility, and interactions with the lattice is
investigated. It is found that electrostatic modifications locally increases
the charge transfer energy and slightly suppresses J. It is further shown that
coupling to c-axis phonons is strongly modified near the dopant. The combined
effects of electrostatic modifications and coupling to the lattice yield
broadened spectral features, reduced charge gap energies, and a sizable local
increase of J. This implies a strong local interplay between
antiferromagnetism, polarons, and superconducting pairing.Comment: 4 figure
Cu -edge Resonant Inelastic X-Ray Scattering in Edge-Sharing Cuprates
We present calculations for resonant inelastic x-ray scattering (RIXS) in
edge-shared copper oxide systems, such as CuGeO and LiCuO,
appropriate for hard x-ray scattering where the photoexcited electron lies
above oxygen 2p and copper 3d orbital energies. We perform exact
diagonalizations of the multi-band Hubbard and determine the energies, orbital
character and resonance profiles of excitations which can be probed via RIXS.
We find excellent agreement with recent results on LiCuO and
CuGeO in the 2-7 eV photon energy loss range.Comment: Updated with new data, expanded 9 pages, 9 figure
Cerebrolysin for acute ischaemic stroke
© 2017 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.Background: Cerebrolysin is a mixture of low-molecular-weight peptides and amino acids derived from pigs' brain tissue, which has potential neuroprotective and neurotrophic properties. It is widely used in the treatment of acute ischaemic stroke in Russia, Eastern Europe, China, and other Asian and post-Soviet countries. Objectives: To assess the benefits and risks of cerebrolysin for treating acute ischaemic stroke. Search methods: In May 2016 we searched the Cochrane Stroke Group Trials Register, CENTRAL, MEDLINE, Embase, Web of Science Core Collection, with Science Citation Index, LILACS, OpenGrey, and a number of Russian Databases. We also searched reference lists, ongoing trials registers and conference proceedings, and contacted the manufacturer of cerebrolysin, EVER Neuro Pharma GmbH (formerly Ebewe Pharma). Selection criteria: Randomised controlled trials (RCTs) comparing cerebrolysin, started within 48 hours of stroke onset and continued for any time, with placebo or no treatment in people with acute ischaemic stroke. Data collection and analysis: Two review authors independently applied inclusion criteria, assessed trial quality and risk of bias, and extracted data. Main results: We identified six RCTs (1501 participants) that met the inclusion criteria. We evaluated risk of bias and judged it to be unclear for generation of allocation sequence in four studies and low in two studies; unclear for allocation concealment in five studies and low in one study; high for incomplete outcome data (attrition bias) in five studies and unclear in one study; unclear for blinding; high for selective reporting in four studies and unclear in two; and high for other sources of bias in three studies and unclear in the rest. The manufacturer of cerebrolysin, pharmaceutical company EVER Neuro Pharma, supported three multi-centre studies, either totally, or providing cerebrolysin and placebo, randomisation codes, research grants, or statisticians. None of the included trials reported on poor functional outcome defined as death or dependence at the end of the follow-up period or early death (within two weeks of stroke onset). All-cause death: we extracted data from five trials (1417 participants). There was no difference in the number of deaths: 46/714 in cerebrolysin group versus 47/703 in placebo group; risk ratio (RR) 0.91 95% confidence interval (CI) 0.61 to 1.35 (5 trials, 1417 participants, moderate-quality evidence). Serious adverse events (SAEs): there was no significant difference in the total number of SAEs with cerebrolysin (RR 1.16, 95% CI 0.81 to 1.67). This comprised no difference in fatal SAEs (RR 0.90, 95% CI 0.59 to 1.38) and an increase in the number of people with non-fatal SAEs (20/667 with cerebrolysin and 8/668 with placebo: RR 2.47, 95% CI 1.09 to 5.58, P = 0.03) (3 trials, 1335 participants, moderate-quality evidence). Total number of people with adverse events: three trials reported on this. There was no difference in the total number of people with adverse events: 308/667 in cerebrolysin group versus 307/668 in placebo group; RR 0.97 95% CI 0.86 to 1.09, random-effects model (3 trials, 1335 participants, moderate-quality evidence). Authors' conclusions: The findings of this Cochrane Review do not demonstrate clinical benefits of cerebrolysin for treating acute ischaemic stroke. We found moderate-quality evidence of an increase in non-fatal SAEs with cerebrolysin use but not in total SAEs
APLIKASI INTERNET OF THINGS MONITORING SUHU ENGINE UNTUK MENCEGAH TERJADINYA OVER HEAT
Tujuan dari penelitian ini untuk mendesain dan membuat sistem online monitoring temperature engine berbasis Internet of Things (IoT). Sistem ini didesain dan dikembangkan untuk memantau temperature engine baik melalui website thingspeak dan aplikasi android virtuino. Sistem terdiri dari beberapa komponen, komponen utama yaitu arduino uno yang akan memperoleh sinyal input dari sensor temperature DS18B20, setelah itu data disimpan di database menggunakan jaringan internet melalui wifi. Peningkatan temperatur ketika engine beroperasi direkam oleh sensor dan akan dikirim ke mikrokontroller yang dapat diakses melalui website ataupun perangkat mobile. Hasil percobaan menunjukkan bahwa selisih nilai pembacaan sensor dengan alat ukur yang terkalibrasi cukup kecil yaitu hanya sebesar 0,14ºc, sedangkan margin error diperoleh 0,14 %. Pengujian alat dilakukan dengan menjalankan engine dengan rentang waktu 1 jam, dan diperoleh temperatur tertinggi engine sebesar 69 ºc dan dapat diakses dengan website dan aplikasi pada perangkat mobile
Unraveling the Nature of Charge Excitations in LaCuO with Momentum-Resolved Cu -edge Resonant Inelastic X-ray Scattering
Results of model calculations using exact diagonalization reveal the orbital
character of states associated with different Raman loss peaks in Cu -edge
resonant inelastic X-ray scattering (RIXS) from LaCuO. The model
includes electronic orbitals necessary to highlight non-local Zhang-Rice
singlet, charge transfer and - excitations, as well as states with apical
oxygen 2 character. The dispersion of these excitations is discussed with
prospects for resonant final state wave-function mapping. A good agreement with
experiments emphasizes the substantial multi-orbital character of RIXS profiles
in the energy transfer range 1-6 eV.Comment: Original: 4.5 pages. Replaced: 4 pages and 4 figures with updated
content and reference
Global simulations of tokamak microturbulence: finite-β effects and collisions
In this paper, we present global nonlinear gyrokinetic simulations including finite beta effects and collisions in tokamak geometry. Global electromagnetic simulations using conventional delta-f particle in cell methods are very demanding, with respect to numerical resources, in order to correctly describe the evolution of the non-adiabatic part of the electron distribution function. This difficulty has been overcome using an appropriate adjustable control variate method in the conventional delta-f scheme. Linearized inter-species and like-species collision operators have also been introduced in the model. The inclusion of the collisional dynamics makes it possible to carry out simulations of microturbulence starting from a global neoclassical equilibrium and to study the effect of collisions on the transport induced by electrostatic microinstabilities
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