11,562 research outputs found
Software digitizer for high granular gaseous detector
A sampling calorimeter equipped with gaseous sensor layers with digital
readout is near perfect for "Particle Flow Algorithm" approach, since it is
homogeneous over large surfaces, robust, cost efficient, easily segmentable to
any readout pad dimension and size and almost insensitive to neutrons. The
response of a finely segmented digital calorimeter is characterized by track
efficiency and multiplicity. Monte Carlo (MC) programs such as GEANT4 simulate
with high precision the energy deposited by particles. The sensor and
electronic response associated to a pad are calculated in a separate
"digitization" process. We developed a general method for simulating the pad
response, a digitization, reproducing efficiency and multiplicity, using the
spatial information from a simulation done at higher granularity. The
digitization method proposed here has been applied to gaseous detectors
including Glass Resistive Plate Chambers (GRPC) and MicroMegas. Validating the
method on test beam data, experimental observables such as efficiency,
multiplicity and mean number of hits at different thresholds have been
reproduced with high precision.Comment: Proceeding for MPGD 201
Electron-Phonon Interactions for Optical Phonon Modes in Few-Layer Graphene
We present a first-principles study of the electron-phonon (e-ph)
interactions and their contributions to the linewidths for the optical phonon
modes at and K in one to three-layer graphene. It is found that due to
the interlayer coupling and the stacking geometry, the high-frequency optical
phonon modes in few-layer graphene couple with different valence and conduction
bands, giving rise to different e-ph interaction strengths for these modes.
Some of the multilayer optical modes derived from the - mode of
monolayer graphene exhibit slightly higher frequencies and much reduced
linewidths. In addition, the linewidths of K- related modes in
multilayers depend on the stacking pattern and decrease with increasing layer
numbers.Comment: 6 pages,5 figures, submitted to PR
Identifying network communities with a high resolution
Community structure is an important property of complex networks. An
automatic discovery of such structure is a fundamental task in many
disciplines, including sociology, biology, engineering, and computer science.
Recently, several community discovery algorithms have been proposed based on
the optimization of a quantity called modularity (Q). However, the problem of
modularity optimization is NP-hard, and the existing approaches often suffer
from prohibitively long running time or poor quality. Furthermore, it has been
recently pointed out that algorithms based on optimizing Q will have a
resolution limit, i.e., communities below a certain scale may not be detected.
In this research, we first propose an efficient heuristic algorithm, Qcut,
which combines spectral graph partitioning and local search to optimize Q.
Using both synthetic and real networks, we show that Qcut can find higher
modularities and is more scalable than the existing algorithms. Furthermore,
using Qcut as an essential component, we propose a recursive algorithm, HQcut,
to solve the resolution limit problem. We show that HQcut can successfully
detect communities at a much finer scale and with a higher accuracy than the
existing algorithms. Finally, we apply Qcut and HQcut to study a
protein-protein interaction network, and show that the combination of the two
algorithms can reveal interesting biological results that may be otherwise
undetectable.Comment: 14 pages, 5 figures. 1 supplemental file at
http://cic.cs.wustl.edu/qcut/supplemental.pd
Prevention and control of Zika fever as a mosquito-borne and sexually transmitted disease
The ongoing Zika virus (ZIKV) epidemic poses a major global public health
emergency. It is known that ZIKV is spread by \textit{Aedes} mosquitoes, recent
studies show that ZIKV can also be transmitted via sexual contact and cases of
sexually transmitted ZIKV have been confirmed in the U.S., France, and Italy.
How sexual transmission affects the spread and control of ZIKV infection is not
well-understood. We presented a mathematical model to investigate the impact of
mosquito-borne and sexual transmission on spread and control of ZIKV and used
the model to fit the ZIKV data in Brazil, Colombia, and El Salvador. Based on
the estimated parameter values, we calculated the median and confidence
interval of the basic reproduction number R0=2.055 (95% CI: 0.523-6.300), in
which the distribution of the percentage of contribution by sexual transmission
is 3.044 (95% CI: 0.123-45.73). Our study indicates that R0 is most sensitive
to the biting rate and mortality rate of mosquitoes while sexual transmission
increases the risk of infection and epidemic size and prolongs the outbreak. In
order to prevent and control the transmission of ZIKV, it must be treated as
not only a mosquito-borne disease but also a sexually transmitted disease
Less precise auditory processing limits instructed L2 speech learning: Communicative focus on phonetic form revisited
Drawing learners' attention to phonetic form during meaning-oriented activities (i.e., communicative focus on form) has been found to be an optimal method of L2 speech training. In the context of 55 Chinese speakers’ English [ɪ] and [i] acquisition (e.g., “sit” vs. “seat”), the current study set out to examine the extent to which the outcomes of such instructed L2 speech learning are tied to individual differences in domain-general auditory processing (precisely representing the acoustic properties of sounds). All the participants engaged in 1.5 h of meaning-oriented instruction. The treatment was carefully manipulated to induce those in the experimental group to attend to the accurate distinction of English [ɪ] and [i]. According to the pre- and post-tests, the experimental group significantly enhanced their English [ɪ] and [i] identification accuracy. However, the follow-up analyses demonstrated that instructional effectiveness was observed especially among those with high levels of auditory processing, but unclear among those with low levels of auditory processing. The findings suggest that the source of individual variation in instructed L2 speech learning stems at least partially from domain-general auditory processing, and that auditory training could help facilitate language learning in some individuals with specific auditory difficulties
Correlation between electrons and vortices in quantum dots
Exact many-body wave functions for quantum dots containing up to four
interacting electrons are computed and we investigated the distribution of the
wave function nodes, also called vortices. For this purpose, we evaluate the
reduced wave function by fixing the positions of all but one electron and
determine the locations of its zeros. We find that the zeros are strongly
correlated with respect to each other and with respect to the position of the
electrons and formulate rules describing their distribution. No multiple zeros
are found, i.e. vortices with vorticity larger than one. Our exact calculations
are compared to results extracted from the recently proposed rotating electron
molecule (REM) wave functions
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