2,205 research outputs found
Large-Scale Spectroscopic Mapping of the Ophiuchi Molecular Cloud Complex I. The CH to NH Ratio as a Signpost of Cloud Characteristics
We present 2.5-square-degree CH N=1-0 and NH J=1-0 maps of the
Ophiuchi molecular cloud complex. These are the first large-scale maps
of the Ophiuchi molecular cloud complex with these two tracers. The
CH emission is spatially more extended than the NH emission. One
faint NH clump Oph-M and one CH ring Oph-RingSW are identified
for the first time. The observed CH to NH abundance ratio
([CH]/[NH]) varies between 5 and 110. We modeled the CH
and NH abundances with 1-D chemical models which show a clear decline
of [CH]/[NH] with chemical age. Such an evolutionary trend is
little affected by temperatures when they are below 40 K. At high density
(n 10 cm), however, the time it takes for the abundance
ratio to drop at least one order of magnitude becomes less than the dynamical
time (e.g., turbulence crossing time 10 years). The observed
[CH]/[NH] difference between L1688 and L1689 can be explained by
L1688 having chemically younger gas in relatively less dense regions. The
observed [CH]/[NH] values are the results of time evolution,
accelerated at higher densities. For the relative low density regions in L1688
where only CH emission was detected, the gas should be chemically younger.Comment: Accepted by ApJ, 45 pages, 10 figure
Learning Compact Features via In-Training Representation Alignment
Deep neural networks (DNNs) for supervised learning can be viewed as a
pipeline of the feature extractor (i.e., last hidden layer) and a linear
classifier (i.e., output layer) that are trained jointly with stochastic
gradient descent (SGD) on the loss function (e.g., cross-entropy). In each
epoch, the true gradient of the loss function is estimated using a mini-batch
sampled from the training set and model parameters are then updated with the
mini-batch gradients. Although the latter provides an unbiased estimation of
the former, they are subject to substantial variances derived from the size and
number of sampled mini-batches, leading to noisy and jumpy updates. To
stabilize such undesirable variance in estimating the true gradients, we
propose In-Training Representation Alignment (ITRA) that explicitly aligns
feature distributions of two different mini-batches with a matching loss in the
SGD training process. We also provide a rigorous analysis of the desirable
effects of the matching loss on feature representation learning: (1) extracting
compact feature representation; (2) reducing over-adaption on mini-batches via
an adaptive weighting mechanism; and (3) accommodating to multi-modalities.
Finally, we conduct large-scale experiments on both image and text
classifications to demonstrate its superior performance to the strong
baselines.Comment: 11 pages, 4 figures, 6 tables. Accepted for publication by AAAI-23.
arXiv admin note: text overlap with arXiv:2002.0991
Role of salivary anti-SSA/B antibodies for diagnosing primary Sjögren’s syndrome
The diagnosis of primary Sjögren’s syndrome (pSS) is complex, and the saliva test is a potential method to improve the existing diagnostic criteria.
Objective: To estimate the diagnostic accuracy of salivary anti-SSA/B antibodies in primary Sjögren’s syndrome
(pSS), and to analyze their correlations with clinical and laboratory profiles.
Study Design: This study enrolled 100 pSS patients and 140 non-pSS controls, including 40 rheumatoid arthritis
(RA) patients, 40 systemic lupus erythematosus (SLE) patients, and 60 healthy controls. Unstimulated whole saliva and stimulated parotid saliva samples were collected from the subjects. Salivary anti-SSA/B antibodies were
measured using an enzyme-linked immunosorbent assay (ELISA). Clinical and laboratory data were retrieved
from the medical records.
Results: In the pSS group, the sensitivity of anti-SSA and anti-SSB antibodies in whole saliva was 49% and 29%,
respectively, and the specificity was 87.5% and 95%. The sensitivity of anti-SSA and anti-SSB antibodies in parotid saliva was 32% and 8%, respectively, and the specificity was 95.52% and 97.86%, respectively. In the pSS
group, the diagnostic accuracy of anti-SSA/B antibodies in whole saliva was significantly higher than in parotid
saliva (
p
<0.05), but was significantly lower than in serum (
p
<0.05). The salivary flow rate in the pSS group posi
-
tive for whole salivary anti-SSA was significantly lower than in the negative group (
p
<0.05). The prevalence of
rheumatoid factor and antinuclear factor were significantly higher in salivary SSB-positive pSS patients than in
SSB-negative patients (
p
<0.05).
Conclusions: Compared to parotid saliva, whole saliva is a more suitable diagnostic fluid. Using salivary anti-
SSA/B antibodies as a single test item is insufficient given the relatively low sensitivity. Further studies should investigate the possibility of combining tests for different salivary autoantibodies as a method for diagnosing pSS
A hybrid single-mode laser based on slotted silicon waveguides
An InGaAsP-Si hybrid single-mode laser based on etched slots in silicon waveguides was demonstrated operating at 1543 nm. The InGaAsP gain structure was bonded onto a patterned silicon-on-insulator wafer by selective area metal bonding method. The mode-selection mechanism based on a slotted silicon waveguide was applied, in which the parameters were designed using the simulation tool cavity modeling framework. The III-V lasers employed buried ridge stripe structure. The whole fabrication process only needs standard photolithography and inductively coupled plasma etching technology, which reduces cost for ease in technology transfer. At room temperature, a single mode of 1543-nm wavelength at a threshold current of 21 mA with a maximum output power of 1.9 mW in continuous-wave regime was obtained. The side mode suppression ratio was larger than 35 dB. The simplicity and flexibility of the fabrication process and a low cost make the slotted hybrid laser a promising light source
Experimental preparation and verification of quantum money
A quantum money scheme enables a trusted bank to provide untrusted users with
verifiable quantum banknotes that cannot be forged. In this work, we report an
experimental demonstration of the preparation and verification of unforgeable
quantum banknotes. We employ a security analysis that takes experimental
imperfections fully into account. We measure a total of states
in one verification round, limiting the forging probability to based
on the security analysis. Our results demonstrate the feasibility of preparing
and verifying quantum banknotes using currently available experimental
techniques.Comment: 12 pages, 4 figure
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