29,611 research outputs found
A high sensitive fiber Bragg grating strain sensor with automatic temperature compensation
A high sensitive fiber Bragg grating (FBG) strain sensor with automatic temperature compensation is demonstrated. FBG is axially linked with a stick and their free ends are fixed to the measured object. When the measured strain changes, the stick does not change in length, but the FBG does. When the temperature changes, the stick changes in length to pull the FBG to realize temperature compensation. In experiments, 1.45 times strain sensitivity of bare FBG with temperature compensation of less than 0.1 nm Bragg wavelength drift over 100 ◦C shift is achieved
Can the 750-GeV diphoton resonance be the singlet Higgs boson of custodial Higgs triplet model?
The observation of diphoton excess around the mass of 750 GeV in LHC Run-II
motivates us to consider whether the singlet Higgs boson in the custodial Higgs
triplet model can serve as a good candidate because an earlier study of
comprehensive parameter scan shows that it can have the right mass in the
viable mass spectra. By assuming the singlet Higgs mass at 750 GeV, its total
width less than 50 GeV and imposing constraints from the LHC 8-TeV data, we
identify an approximately linear region on the plane along
which the exotic Higgs boson masses satisfy a specific hierarchy and have lower
possible spectra, where denotes the triplet vacuum expectation value
and is the mixing angle between the singlet Higgs boson and the
standard model-like Higgs boson. Although the diphoton decay rate can be
enhanced by charged Higgs bosons running in the loop in this region, it is
mostly orders of magnitude smaller than that required for the observed
production rate, except for the small region when the diphoton
fusion production mechanism becomes dominant. Nonetheless, this part of
parameter space suffers from the problems of breakdown of perturbativity and
large uncertainties in the photon parton distribution function of proton.Comment: 14 pages, 2 figures, and 2 tables; bugs in numerical calculations
fixed, and discussions and conclusions changed; typo corrected; 16 pages,
expanded with more detailed discussions, updated figures and tables, version
to appear in the journa
Genes Translocated into the Plastid Inverted Repeat Show Decelerated Substitution Rates and Elevated GC Content.
Plant chloroplast genomes (plastomes) are characterized by an inverted repeat (IR) region and two larger single copy (SC) regions. Patterns of molecular evolution in the IR and SC regions differ, most notably by a reduced rate of nucleotide substitution in the IR compared to the SC region. In addition, the organization and structure of plastomes is fluid, and rearrangements through time have repeatedly shuffled genes into and out of the IR, providing recurrent natural experiments on how chloroplast genome structure can impact rates and patterns of molecular evolution. Here we examine four loci (psbA, ycf2, rps7, and rps12 exon 2-3) that were translocated from the SC into the IR during fern evolution. We use a model-based method, within a phylogenetic context, to test for substitution rate shifts. All four loci show a significant, 2- to 3-fold deceleration in their substitution rate following translocation into the IR, a phenomenon not observed in any other, nontranslocated plastid genes. Also, we show that after translocation, the GC content of the third codon position and of the noncoding regions is significantly increased, implying that gene conversion within the IR is GC-biased. Taken together, our results suggest that the IR region not only reduces substitution rates, but also impacts nucleotide composition. This finding highlights a potential vulnerability of correlating substitution rate heterogeneity with organismal life history traits without knowledge of the underlying genome structure
Detecting Outliers in Data with Correlated Measures
Advances in sensor technology have enabled the collection of large-scale
datasets. Such datasets can be extremely noisy and often contain a significant
amount of outliers that result from sensor malfunction or human operation
faults. In order to utilize such data for real-world applications, it is
critical to detect outliers so that models built from these datasets will not
be skewed by outliers.
In this paper, we propose a new outlier detection method that utilizes the
correlations in the data (e.g., taxi trip distance vs. trip time). Different
from existing outlier detection methods, we build a robust regression model
that explicitly models the outliers and detects outliers simultaneously with
the model fitting.
We validate our approach on real-world datasets against methods specifically
designed for each dataset as well as the state of the art outlier detectors.
Our outlier detection method achieves better performances, demonstrating the
robustness and generality of our method. Last, we report interesting case
studies on some outliers that result from atypical events.Comment: 10 page
Extracting entangled qubits from Majorana fermions in quantum dot chains through the measurement of parity
We propose a scheme for extracting entangled charge qubits from quantum-dot
chains that support zero-energy edge modes. The edge mode is composed of
Majorana fermions localized at the ends of each chain. The qubit, logically
encoded in double quantum dots, can be manipulated through tunneling and
pairing interactions between them. The detailed form of the entangled state
depends on both the parity measurement (an even or odd number) of the
boundary-site electrons in each chain and the teleportation between the chains.
The parity measurement is realized through the dispersive coupling of
coherent-state microwave photons to the boundary sites, while the teleportation
is performed via Bell measurements. Our scheme illustrates \emph{localizable
entanglement} in a fermionic system, which serves feasibly as a quantum
repeater under realistic experimental conditions, as it allows for finite
temperature effect and is robust against disorders, decoherence and
quasi-particle poisoning.Comment: Accepted by Scientific Report
Interdot Coulomb repulsion effect on the charge transport of parallel double single electron transistors
The charge transport behaviors of parallel double single electron transistors
(SETs) are investigated by the Anderson model with two impurity levels. The
nonequilibrium Keldysh Green's technique is used to calculate the
current-voltage characteristics of system. For SETs implemented by quantum dots
(QDs) embedded into a thin layer, the interdot Coulomb repulsion is
more important than the interdot electron hopping as a result of high potential
barrier height between QDs and . We found that the interdot Coulomb
repulsion not onlyleads to new resonant levels, but also creates negative
differential conductances.Comment: 12 pages, 7 figure
Thermal rectification effects of multiple semiconductor quantum dot junctions
Based on the multiple energy level Anderson model, this study theoretically
examines the thermoelectric effects of semiconductor quantum dots (QDs) in the
nonlinear response regime. The charge and heat currents in the sequential
tunneling process are calculated by using the Keldysh Green's function
technique. Results show that the thermal rectification effect can be observed
in a multiple QD junction system, whereas the tunneling rate, size fluctuation,
and location distribution of QD significantly influence the rectification
efficiency.Comment: 5 pages, 8figure
Radiative corrections to Higgs couplings with weak gauge bosons in custodial multi-Higgs models
We calculate 1-loop radiative corrections to the and couplings in
models with next--to--simplest Higgs sectors satisfying the electroweak
parameter equal to 1 at tree level: the Higgs singlet model, the two-Higgs
doublet models, and the Georgi-Machacek model. Under theoretical and current
experimental constraints, the three models have different correlations between
the deviations in the and couplings from the standard model
predictions. In particular, we find for each model predictions with no overlap
with the other two models.Comment: 5 pages, 1 figur
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