522 research outputs found
Bench-to-bedside review : targeting antioxidants to mitochondria in sepsis
Peer reviewedPublisher PD
Integrated photonic quantum gates for polarization qubits
Integrated photonic circuits have a strong potential to perform quantum
information processing. Indeed, the ability to manipulate quantum states of
light by integrated devices may open new perspectives both for fundamental
tests of quantum mechanics and for novel technological applications. However,
the technology for handling polarization encoded qubits, the most commonly
adopted approach, is still missing in quantum optical circuits. Here we
demonstrate the first integrated photonic Controlled-NOT (CNOT) gate for
polarization encoded qubits. This result has been enabled by the integration,
based on femtosecond laser waveguide writing, of partially polarizing beam
splitters on a glass chip. We characterize the logical truth table of the
quantum gate demonstrating its high fidelity to the expected one. In addition,
we show the ability of this gate to transform separable states into entangled
ones and vice versa. Finally, the full accessibility of our device is exploited
to carry out a complete characterization of the CNOT gate through a quantum
process tomography.Comment: 6 pages, 4 figure
Preferential Paths of Air-water Two-phase Flow in Porous Structures with Special Consideration of Channel Thickness Effects.
Accurate understanding and predicting the flow paths of immiscible two-phase flow in rocky porous structures are of critical importance for the evaluation of oil or gas recovery and prediction of rock slides caused by gas-liquid flow. A 2D phase field model was established for compressible air-water two-phase flow in heterogenous porous structures. The dynamic characteristics of air-water two-phase interface and preferential paths in porous structures were simulated. The factors affecting the path selection of two-phase flow in porous structures were analyzed. Transparent physical models of complex porous structures were prepared using 3D printing technology. Tracer dye was used to visually observe the flow characteristics and path selection in air-water two-phase displacement experiments. The experimental observations agree with the numerical results used to validate the accuracy of phase field model. The effects of channel thickness on the air-water two-phase flow behavior and paths in porous structures were also analyzed. The results indicate that thick channels can induce secondary air flow paths due to the increase in flow resistance; consequently, the flow distribution is different from that in narrow channels. This study provides a new reference for quantitatively analyzing multi-phase flow and predicting the preferential paths of immiscible fluids in porous structures
Magnetism and its microscopic origin in iron-based high-temperature superconductors
High-temperature superconductivity in the iron-based materials emerges from,
or sometimes coexists with, their metallic or insulating parent compound
states. This is surprising since these undoped states display dramatically
different antiferromagnetic (AF) spin arrangements and Nel
temperatures. Although there is general consensus that magnetic interactions
are important for superconductivity, much is still unknown concerning the
microscopic origin of the magnetic states. In this review, progress in this
area is summarized, focusing on recent experimental and theoretical results and
discussing their microscopic implications. It is concluded that the parent
compounds are in a state that is more complex than implied by a simple Fermi
surface nesting scenario, and a dual description including both itinerant and
localized degrees of freedom is needed to properly describe these fascinating
materials.Comment: 14 pages, 4 figures, Review article, accepted for publication in
Nature Physic
At what institutions did Nobel laureates do their prize-winning work? An analysis of biographical information on Nobel laureates from 1994 to 2014
Metabolic syndrome in a Taiwanese metropolitan adult population
<p>Abstract</p> <p>Background</p> <p>Metabolic syndrome (MS) is a combination of medical disorders that increase one's risk for cardiovascular disease and diabetes. Little information exists on the prevalence of MS in a general adult population in Taiwan.</p> <p>Methods</p> <p>We did a cross-sectional survey in a representative sample of 2,359 Chinese adults aged 40 years and over who lived in a metropolitan city, Taiwan in 2004–05. MS was defined by Adult Treatment Panel III criteria modified for Asians.</p> <p>Results</p> <p>The prevalence of MetS was 35.32% and 43.23% in men aged 40–64 years and 65 years and over, respectively, and 24.19% and 51.82% in women aged 40–64 years and 65 years and over. Older age, postmenopausal status, higher body mass index, current smoking, low education attainment, low household income, no alcohol consumption, lower level of occupation physical activity, and a family history of diabetes were associated with increased odds of MetS.</p> <p>Conclusion</p> <p>MetS was present in more than 30% of the Taiwan adult population aged 40 years and over in a metropolitan area; there were substantial variations by age and body mass index groups.</p
Flow-volume loops derived from three-dimensional echocardiography: a novel approach to the assessment of left ventricular hemodynamics
BACKGROUND: This study explores the feasibility of non-invasive evaluation of left ventricular (LV) flow-volume dynamics using 3-dimensional (3D) echocardiography, and the capacity of such an approach to identify altered LV hemodynamic states caused by valvular abnormalities. METHODS: Thirty-one patients with moderate-severe aortic (AS) and mitral (MS) stenoses (21 and 10 patients, respectively) and 10 healthy volunteers underwent 3D echocardiography with full volume acquisition using Philips Sonos 7500 equipment. The digital 3D data were post- processed using TomTec software. LV flow-volume loops were subsequently constructed for each subject by plotting instantaneous LV volume data sampled throughout the cardiac cycle vs. their first derivative representing LV flow. After correction for body surface area, an average flow-volume loop was calculated for each subject group. RESULTS: Flow-volume loops were obtainable in all subjects, except 3 patients with AS. The flow-volume diagrams displayed clear differences in the form and position of the loops between normal individuals and the respective patient groups. In patients with AS, an "obstructive" pattern was observed, with lower flow values during early systole and larger end-systolic volume. On the other hand, patients with MS displayed a "restrictive" flow-volume pattern, with reduced diastolic filling and smaller end-diastolic volume. CONCLUSION: Non-invasive evaluation of LV flow-volume dynamics using 3D-echocardiographic data is technically possible and the approach has a capacity to identify certain specific types of alteration of LV flow-volume pattern caused by valvular abnormalities, thus reflecting underlying hemodynamic states specific for these abnormalities
Experimental investigation of the entanglement-assisted entropic uncertainty principle
The uncertainty principle, which bounds the uncertainties involved in
obtaining precise outcomes for two complementary variables defining a quantum
particle, is a crucial aspect in quantum mechanics. Recently, the uncertainty
principle in terms of entropy has been extended to the case involving quantum
entanglement. With previously obtained quantum information for the particle of
interest, the outcomes of both non-commuting observables can be predicted
precisely, which greatly generalises the uncertainty relation. Here, we
experimentally investigated the entanglement-assisted entropic uncertainty
principle for an entirely optical setup. The uncertainty is shown to be near
zero in the presence of quasi-maximal entanglement. The new uncertainty
relation is further used to witness entanglement. The verified entropic
uncertainty relation provides an intriguing perspective in that it implies the
uncertainty principle is not only observable-dependent but is also
observer-dependent.Comment: 14 pages, 5 figure
Magnetotransport in an aluminum thin film on a GaAs substrate grown by molecular beam epitaxy
Magnetotransport measurements are performed on an aluminum thin film grown on a GaAs substrate. A crossover from electron- to hole-dominant transport can be inferred from both longitudinal resistivity and Hall resistivity with increasing the perpendicular magnetic field B. Also, phenomena of localization effects can be seen at low B. By analyzing the zero-field resistivity as a function of temperature T, we show the importance of surface scattering in such a nanoscale film
Precise measurement of the W-boson mass with the CDF II detector
We have measured the W-boson mass MW using data corresponding to 2.2/fb of
integrated luminosity collected in proton-antiproton collisions at 1.96 TeV
with the CDF II detector at the Fermilab Tevatron collider. Samples consisting
of 470126 W->enu candidates and 624708 W->munu candidates yield the measurement
MW = 80387 +- 12 (stat) +- 15 (syst) = 80387 +- 19 MeV. This is the most
precise measurement of the W-boson mass to date and significantly exceeds the
precision of all previous measurements combined
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