863 research outputs found
An approximate diagonalization method for large scale Hamiltonians
Full text linkAn approximate diagonalization method is proposed that combines exact
diagonalization and perturbation expansion to calculate low energy eigenvalues
and eigenfunctions of a Hamiltonian. The method involves deriving an effective
Hamiltonian for each eigenvalue to be calculated, using perturbation expansion,
and extracting the eigenvalue from the diagonalization of the effective
Hamiltonian. The size of the effective Hamiltonian can be significantly smaller
than that of the original Hamiltonian, hence the diagonalization can be done
much faster. We compare the results of our method with those obtained using
exact diagonalization and quantum Monte Carlo calculation for random problem
instances with up to 128 qubits.Comment: 5 pages, 3 figure
Application of 3D GIS to improve the effect of kriging method in ore reserves estimation and mining : abstract
Get PDFTuning phase-stability and short-range order through Al-doping in (CoCrFeMn)100-xAlx high entropy alloys
Get PDFFor (CoCrFeMn)Al high-entropy alloys, we investigate the
phase evolution with increasing Al-content (0 x 20 at.%). From
first-principles theory, the Al-doping drives the alloy structurally from FCC
to BCC separated by a narrow two-phase region (FCC+BCC), which is well
supported by our experiments. We highlight the effect of Al-doping on the
formation enthalpy and electronic structure of (CoCrFeMn)Al
alloys. As chemical short-range order (SRO) in multicomponent alloys indicates
the nascent local order (and entropy changes), as well as expected
low-temperature ordering behavior, we use thermodynamic linear-response within
density-functional theory to predict SRO and ordering transformation and
temperatures inherent in (CoCrFeMn)Al. The predictions agree
with our present experimental findings, and other reported ones.Comment: 27 pages, 9 figures, 1 tabl
Six-month outcomes from Living Well with Diabetes: a randomized trial of a telephone-delivered weight loss and physical activity intervention to improve glycemic control
Get PDFIntensive lifestyle intervention trials in type 2 diabetes contribute evidence on what can be achieved under optimal conditions, but are less informative for translation in applied settings
Tuning phase-stability and short-range order through AI-doping in (CoCrFeMn)100-xAIx high entropy alloys
Get PDFFor (CoCrFeMn)100−xAlx high-entropy alloys, we investigate the phase evolution with increasing Al content (0≤x≤20 at.%). From first-principles theory, aluminum doping drives the alloy structurally from fcc to bcc separated by a narrow two-phase region (fcc+bcc), which is well supported by our experiments. Using KKR-CPA electronic-structure calculations, we highlight the effect of Al doping on the formation enthalpy (alloy stability) and electronic dispersion of (CoCrFeMn)100−xAlx alloys. As chemical short-range order indicates the nascent local order, and entropy changes, as well as expected low-temperature ordering behavior, we use KKR-CPA-based thermodynamic linear response to predict the chemical ordering behavior of arbitrary complex solid-solution alloys—an ideal approach for predictive design of high-entropy alloys. The predictions agree with our present experimental findings and other reported ones
Review of recent experimental progresses in Foundations of Quantum Mechanics and Quantum Information obtained in Parametric Down Conversion Experiments at IENGF
Full text linkWe review some recent experimental progresses concerning Foundations of
Quantum Mechanics and Quantum Information obtained in Quantum Optics Laboratory
"Carlo Novero" at IENGF.
More in details, after a short presentation of our polarization entangled
photons source (based on precise superposition of two Type I PDC emission) and
of the results obtained with it, we describe an innovative double slit
experiment where two degenerate photons produced by PDC are sent each to a
specific slit. Beyond representing an interesting example of relation between
visibility of interference and "welcher weg" knowledge, this configuration has
been suggested for testing de Broglie-Bohm theory against Standard Quantum
Mechanics. Our results perfectly fit SQM results, but disagree with dBB
predictions.
Then, we discuss a recent experiment addressed to clarify the issue of which
wave-particle observables are really to be considered when discussing wave
particle duality. This experiments realises the Agarwal et al. theoretical
proposal, overcoming limitations of a former experiment.
Finally, we hint to the realization of a high-intensity
high-spectral-selected PDC source to be used for quantum information studies
The Nearby Evolved Stars Survey I. JCMT/SCUBA-2 Submillimeter Detection of the Detached Shell of U Antliae
Get PDFWe present the highest resolution single-dish submillimetre observations of the detached shell source U Antliae to date. The observations were obtained at 450 and 850m with SCUBA-2 instrument on the James Clerk Maxwell Telescope as part of the Nearby Evolved Stars Survey. The emission at 850m peaks at 40 arcsec with hints of a second peak seen at 20 arcsec. The emission can be traced out to a radius of 56 arcsec at a 3 level. The outer peak observed at 850m aligns well with the peak observed at Herschel/PACS wavelengths. With the help of spectral energy distribution fitting and radiative transfer calculations of multiple-shell models for the circumstellar envelope, we explore the various shell structures and the variation of grain sizes along the in the circumstellar envelope. We determine a total shell dust mass of (2.0 0.3) 105 M and established that the thermal pulse that gave rise to the detached shell occurred 3500 500 yr ago
Coping Skills and Parent Support Mediate the Association Between Childhood Attention-Deficit/Hyperactivity Disorder and Adolescent Cigarette Use
Get PDFTo examine mediators of the association between childhood attention-deficit/hyperactivity disorder (ADHD) and adolescent cigarette use
Compatibility of MAX phase-based ceramics with oxygen-poor, static liquid lead-bismuth eutectic
Get PDFThis work investigates the compatibility of MAX phase-based
ceramics with liquid LBE, and proposes a mechanism to explain the observed
local /LBE interaction. The ceramics were exposed to oxygen-poor
( mass%), static liquid LBE at 500{\deg}C for 1000
h. A new MAX phase solid solution formed in-situ in the
LBE-affected grains. Out-of-plane ordering was favorable in the new
solid solution, whereby -layers with high and low-Bi/Pb contents
alternated in the crystal structure, in agreement with first-principles
calculations. Bulk was synthesized by reactive hot pressing
to study the crystal structure of the solid solution by neutron diffraction
Barriers to the provision of smoking cessation assistance:A qualitative study among Romanian family physicians
Get PDFBACKGROUND: Smoking cessation is the most effective intervention to prevent and slow down the progression of several respiratory and other diseases and improve patient outcomes. Romania has legislation and a national tobacco control programme in line with the World Health Organization Framework for Tobacco Control. However, few smokers are advised to quit by their family physicians (FPs). AIM: To identify and explore the perceived barriers that prevent Romanian FPs from engaging in smoking cessation with patients. METHODS: A qualitative study was undertaken. A total of 41 FPs were recruited purposively from Bucharest and rural areas within 600 km of the city. Ten FPs took part in a focus group and 31 participated in semistructured interviews. Analysis was descriptive, inductive and themed, according to the barriers experienced. RESULTS: Five main barriers were identified: limited perceived role for FPs; lack of time during consultations; past experience and presence of disincentives; patients' inability to afford medication; and lack of training in smoking cessation skills. Overarching these specific barriers were key themes of a medical and societal hierarchy, which undermined the FP role, stretched resources and constrained care. CONCLUSIONS: Many of the barriers described by the Romanian FPs reflected universally recognised challenges to the provision of smoking cessation advice. The context of a relatively hierarchical health-care system and limitations of time and resources exacerbated many of the problems and created new barriers that will need to be addressed if Romania is to achieve the aims of its National Programme Against Tobacco Consumption
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