19,080 research outputs found
The X-ray Outburst of H1743-322: High-Frequency QPOs with a 3:2 Frequency Ratio
We observed the 2003 X-ray outburst of H1743-322 in a series of 130 pointed
observation with RXTE. We searched individual observations for high-frequency
QPOs (HFQPOs) and found only weak or marginal detections near 240 and 160 Hz.
We next grouped the observations in several different ways and computed the
average power-density spectra (PDS) in a search for further evidence of HFQPOs.
This effort yielded two significant results for those observations defined by
the presence of low-frequency QPOs (0.1-20 Hz) and an absence of
``band-limited'' power continua: (1) The 9 time intervals with the highest 7-35
keV count rates yielded an average PDS with a QPO at Hz. (; 3--35 keV); and (2) a second group with lower 7-35 keV count rates (26
intervals) produced an average PDS with a QPO at Hz (;
7--35 keV). The ratio of these two frequencies is . This finding
is consistent with results obtained for three other black hole systems that
exhibit commensurate HFQPOs in a 3:2 ratio. Furthermore, the occurrence of
H1743-322's slower HFQPO at times of higher X-ray luminosity closely resembles
the behavior of XTE J1550-564 and GRO J1655-40. We discuss our results in terms
of a resonance model that invokes frequencies set by general relativity for
orbital motions near a black-hole event horizon.Comment: 12 pages, 3 figures, submitted to Ap
Probing Phases and Quantum Criticality using Deviations from the Local Fluctuation-Dissipation Theorem
Introduction Cold atomic gases in optical lattices are emerging as excellent
laboratories for testing models of strongly interacting particles in condensed
matter physics. Currently, one of the major open questions is how to obtain the
finite temperature phase diagram of a given quantum Hamiltonian directly from
experiments. Previous work in this direction required quantum Monte Carlo
simulations to directly model the experimental situation in order to extract
quantitative information, clearly defeating the purpose of an optical lattice
emulator. Here we propose a new method that utilizes deviations from a local
fluctuation dissipation theorem to construct a finite temperature phase
diagram, for the first time, from local observables accessible by in situ
experimental observations. Our approach extends the utility of the
fluctuation-dissipation theorem from thermometry to the identification of
quantum phases, associated energy scales and the quantum critical region. We
test our ideas using state-of-the-art large-scale quantum Monte Carlo
simulations of the two-dimensional Bose Hubbard model.Comment: 7 pages; 4 figures; also see supplementary material of 7 pages with 3
figure
Landau level mixing by full spin-orbit interactions
We study a two-dimensional electron gas in a perpendicular magnetic field in
the presence of both Rashba and Dresselhaus spin-orbit interactions. Using a
Bogoliubov transformation we are able to write an approximate formula for the
Landau levels, thanks to the simpler form of the resulting Hamiltonian. The
exact numerical calculation of the energy levels, is also made simpler by our
formulation. The approximate formula and the exact numerical results show
excellent agreement for typical semiconductors, especially at high magnetic
fields. We also show how effective Zeeman coupling is modified by spin-orbit
interactions.Comment: 5 pages, 5 figure
Clinical Improvement of Weight, HbA1c and Liver Function by Rybelsus (Oral Semaglutide) In Patient with Type 2 Diabetes (T2D), Obesity and Fatty Liver
Background: As glucagon-like-peptide 1 receptor agonist (GLP1-RA), oral semaglutide (Rybelsus) has been latest topic.
Case presentation: Patient is 72-year-old male with T2D, obesity, fatty liver and hypertension. He showed BMI 32.4 kg/m2 and HbA1c 8.1% in Nov 2021.
Results: He started Rybelsus 3-7mg/day, and HbA1c and weight decreased for 8.1% to 7.0% and 92kg to 86.5kg with ALT/GGT improvement without gastrointestinal adverse events (GIAEs).
Discussion: This case has arteriosclerotic cardiovascular disease (ASCVD). From cardiovascular outcome trials (CVOTs), semaglutide group revealed lower odd ratio (OR) for less CV death, as 0.47 of exenatide, 0.46 of dulaglutide and 0.43 of lixisenatide
Ensemble averageability in network spectra
The extreme eigenvalues of connectivity matrices govern the influence of the
network structure on a number of network dynamical processes. A fundamental
open question is whether the eigenvalues of large networks are well represented
by ensemble averages. Here we investigate this question explicitly and validate
the concept of ensemble averageability in random scale-free networks by showing
that the ensemble distributions of extreme eigenvalues converge to peaked
distributions as the system size increases. We discuss the significance of this
result using synchronization and epidemic spreading as example processes.Comment: 4 pages, 4 figure
Efeito da inoculação de fungos micorrÃzicos vesicular-arbusculares em urucuzeiro (Bixa orellana L.).
bitstream/item/32553/1/CPATU-BP128.pd
A novel fast gas chromatography method for higher time resolution measurements of speciated monoterpenes in air
Biogenic emissions supply the largest fraction of non-methane volatile
organic compounds (VOC) from the biosphere to the atmospheric boundary
layer, and typically comprise a complex mixture of reactive terpenes. Due to
this chemical complexity, achieving comprehensive measurements of biogenic
VOC (BVOC) in air within a satisfactory time resolution is analytically
challenging. To address this, we have developed a novel, fully automated
Fast Gas Chromatography (Fast-GC) based technique to provide higher time
resolution monitoring of monoterpenes (and selected other C<sub>9</sub>-C<sub>15</sub>
terpenes) during plant emission studies and in ambient air. To our
knowledge, this is the first study to apply a Fast-GC based separation
technique to achieve quantification of terpenes in ambient air. Three
chromatography methods have been developed for atmospheric terpene analysis
under different sampling scenarios. Each method facilitates chromatographic
separation of selected BVOC within a significantly reduced analysis time
compared to conventional GC methods, whilst maintaining the ability to
quantify individual monoterpene structural isomers. Using this approach, the
C<sub>9</sub>-C<sub>15</sub> BVOC composition of single plant emissions may be
characterised within a 14.5 min analysis time. Moreover, in-situ
quantification of 12 monoterpenes in unpolluted ambient air may be achieved
within an 11.7 min chromatographic separation time (increasing to 19.7 min
when simultaneous quantification of multiple oxygenated C<sub>9</sub>-C<sub>10</sub>
terpenoids is required, and/or when concentrations of anthropogenic VOC are
significant). These analysis times potentially allow for a twofold to fivefold
increase in measurement frequency compared to conventional GC methods. Here we outline the technical
details and analytical capability of this chromatographic approach, and
present the first in-situ Fast-GC observations of 6 monoterpenes and the
oxygenated BVOC (OBVOC) linalool in ambient air. During this field
deployment within a suburban forest ~30 km west of central
Tokyo, Japan, the Fast-GC limit of detection with respect to monoterpenes
was 4–5 ppt, and the agreement between Fast-GC and PTR-MS derived total
monoterpene mixing ratios was consistent with previous GC/PTR-MS
comparisons. The measurement uncertainties associated with the Fast-GC
quantification of monoterpenes are ≤ 12%, while larger uncertainties
(up to ~25%) are associated with the OBVOC and
sesquiterpene measurements
Impurity Effect on Kramer-Pesch Core Shrinkage in s-Wave Vortex and Chiral p-Wave Vortex
The low-temperature shrinking of the vortex core (Kramer-Pesch effect) is
studied for an isolated single vortex for chiral p-wave and s-wave
superconducting phases. The effect of nonmagnetic impurities on the vortex core
radius is numerically investigated in the Born limit by means of a
quasiclassical approach. It is shown that in the chiral p-wave phase the
Kramer-Pesch effect displays a certain robustness against impurities owing to a
specific quantum effect, while the s-wave phase reacts more sensitively to
impurity scattering. This suggests chiral p-wave superconductors as promising
candidates for the experimental observation of the Kramer-Pesch effect.Comment: 18 pages, 4 figures; to be published in J. Low Temp. Phys.; Proc. of
NATO ARW: VORTEX 2004, Yalta (Uknaine
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