72,173 research outputs found
Air Temperature Comparison between the MMTS and the USCRN Temperature Systems
A new U.S. Climate Reference Network (USCRN) was officially and nationally commissioned by the Department of Commerce and the National Oceanic and Atmospheric Administration in 2004. During a 1-yr side-by-side field comparison of USCRN temperatures and temperatures measured by a maximum-minimum temperature system (MMTS), analyses of hourly data show that the MMTS temperature performed with biases: 1) a systematic bias–ambient-temperature-dependent bias and 2) an ambient-solar-radiation- and ambient-wind- speed-dependent bias. Magnitudes of these two biases ranged from a few tenths of a degree to over 1C compared to the USCRN temperatures. The hourly average temperatures for the USCRN were the dependent variables in the development of two statistical models that remove the biases due to ambient temperature, ambient solar radiation, and ambient wind speed in the MMTS. The model performance was examined, and the results show that the adjusted MMTS data were substantially improved with respect to both systematic bias and the bias associated with ambient solar radiation and ambient wind speed. In addition, the results indicate that the historical temperature datasets prior to the MMTS era need to be further investigated to produce long-term homogenous times series of area-average temperature
A large-scale one-way quantum computer in an array of coupled cavities
We propose an efficient method to realize a large-scale one-way quantum
computer in a two-dimensional (2D) array of coupled cavities, based on coherent
displacements of an arbitrary state of cavity fields in a closed phase space.
Due to the nontrivial geometric phase shifts accumulating only between the
qubits in nearest-neighbor cavities, a large-scale 2D cluster state can be
created within a short time. We discuss the feasibility of our method for scale
solid-state quantum computationComment: 5 pages, 3 figure
Tracking intracavernously injected adipose-derived stem cells to bone marrow.
The intracavernous (i.c.) injection of stem cells (SCs) has been shown to improve erectile function in various erectile dysfunction (ED) animal models. However, the tissue distribution of the injected cells remains unknown. In this study we tracked i.c.-injected adipose-derived stem cells (ADSCs) in various tissues. Rat paratesticular fat was processed for ADSC isolation and culture. The animals were then subject to cavernous nerve (CN) crush injury or sham operation, followed by i.c. injection of 1 million autologous or allogeneic ADSCs that were labeled with 5-ethynyl-2-deoxyuridine (EdU). Another group of rats received i.c. injection of EdU-labeled allogeneic penile smooth muscle cells (PSMCs). At 2 and 7 days post injection, penises and femoral bone marrow were processed for histological analyses. Whole femoral bone marrows were also analyzed for EdU-positive cells by flow cytometry. The results show that ADSCs exited the penis within days of i.c. injection and migrated preferentially to bone marrow. Allogenicity did not affect the bone marrow appearance of ADSCs at either 2 or 7 days, whereas CN injury reduced the number of ADSCs in bone marrow significantly at 7 but not 2 days. The significance of these results in relation to SC therapy for ED is discussed
Magnification relations of quad lenses and applications on Einstein crosses
In this work, we mainly study the magnification relations of quad lens models
for cusp, fold and cross configurations. By dividing and ray-tracing in
different image regions, we numerically derive the positions and magnifications
of the four images for a point source lying inside of the astroid caustic.
Then, based on the magnifications, we calculate the signed cusp and fold
relations for the singular isothermal elliptical lenses. The signed fold
relation map has positive and negative regions, and the positive region is
usually larger than the negative region as has been confirmed before. It can
also explain that for many observed fold image pairs, the fluxes of the Fermat
minimum images are apt to be larger than those of the saddle images. We define
a new quantity cross relation which describes the magnification discrepancy
between two minimum images and two saddle images. Distance ratio is also
defined as the ratio of the distance of two saddle images to that of two
minimum images. We calculate the cross relations and distance ratios for nine
observed Einstein crosses. In theory, for most of the quad lens models, the
cross relations decrease as the distance ratios increase. In observation, the
cross relations of the nine samples do not agree with the quad lens models very
well, nevertheless, the cross relations of the nine samples do not give obvious
evidence for anomalous flux ratio as the cusp and fold types do. Then, we
discuss several reasons for the disagreement, and expect good consistencies for
more precise observations and better lens models in the future.Comment: 12 pages, 11 figures, accepted for publication in MNRA
Wilson ratio of Fermi gases in one dimension
We calculate the Wilson ratio of the one-dimensional Fermi gas with spin
imbalance. The Wilson ratio of attractively interacting fermions is solely
determined by the density stiffness and sound velocity of pairs and of excess
fermions for the two-component Tomonaga-Luttinger liquid (TLL) phase. The ratio
exhibits anomalous enhancement at the two critical points due to the sudden
change in the density of states. Despite a breakdown of the quasiparticle
description in one dimension, two important features of the Fermi liquid are
retained, namely the specific heat is linearly proportional to temperature
whereas the susceptibility is independent of temperature. In contrast to the
phenomenological TLL parameter, the Wilson ratio provides a powerful parameter
for testing universal quantum liquids of interacting fermions in one, two and
three dimensions.Comment: 5+2 pages, 4+1 figures, Eq. (4) is proved, figures were refine
Multipole Gravitational Lensing and High-order Perturbations on the Quadrupole Lens
An arbitrary surface mass density of gravitational lens can be decomposed
into multipole components. We simulate the ray-tracing for the multipolar mass
distribution of generalized SIS (Singular Isothermal Sphere) model, based on
the deflection angles which are analytically calculated. The magnification
patterns in the source plane are then derived from inverse shooting technique.
As have been found, the caustics of odd mode lenses are composed of two
overlapping layers for some lens models. When a point source traverses such
kind of overlapping caustics, the image numbers change by \pm 4, rather than
\pm 2. There are two kinds of images for the caustics. One is the critical
curve and the other is the transition locus. It is found that the image number
of the fold is exactly the average value of image numbers on two sides of the
fold, while the image number of the cusp is equal to the smaller one. We also
focus on the magnification patterns of the quadrupole (m = 2) lenses under the
perturbations of m = 3, 4 and 5 mode components, and found that one, two, and
three butterfly or swallowtail singularities can be produced respectively. With
the increasing intensity of the high-order perturbations, the singularities
grow up to bring sixfold image regions. If these perturbations are large enough
to let two or three of the butterflies or swallowtails contact, eightfold or
tenfold image regions can be produced as well. The possible astronomical
applications are discussed.Comment: 24 pages, 6 figure
Performance of Photosensors in the PandaX-I Experiment
We report the long term performance of the photosensors, 143 one-inch
R8520-406 and 37 three-inch R11410-MOD photomultipliers from Hamamatsu, in the
first phase of the PandaX dual-phase xenon dark matter experiment. This is the
first time that a significant number of R11410 photomultiplier tubes were
operated in liquid xenon for an extended period, providing important guidance
to the future large xenon-based dark matter experiments.Comment: v3 as accepted by JINST with modifications based on reviewers'
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