1,390 research outputs found
Bayesian Inference of Supernova Neutrino Spectra with Multiple Detectors
We implement the Bayesian inference to retrieve energy spectra of all
neutrinos from a galactic core-collapse supernova (CCSN). To achieve high
statistics and full sensitivity to all flavours of neutrinos, we adopt a
combination of several reaction channels from different large-scale neutrino
observatories, namely inverse beta decay on proton and elastic scattering on
electron from Hyper-Kamiokande (Hyper-K), charged current absorption on Argon
from Deep Underground Neutrino Experiment (DUNE) and coherent elastic
scattering on Lead from RES-NOVA. Assuming no neutrino oscillation or specific
oscillation models, we obtain mock data for each channel through Poisson
processes with the predictions, for a typical source distance of 10 kpc in our
Galaxy, and then evaluate the probability distributions for all spectral
parameters of theoretical neutrino spectrum model with Bayes' theorem. Although
the results for either the electron-neutrinos or electron-antineutrinos reserve
relatively large uncertainties (according to the neutrino mass hierarchy), a
precision of a few percent (i.e., at a credible
interval of ) is achieved for primary spectral parameters (e.g., mean
energy and total emitted energy) of other neutrino species. Moreover, the
correlation coefficients between different parameters are computed as well and
interesting patterns are found. Especially, the mixing-induced correlations are
sensitive to the neutrino mass hierarchy, which potentially makes it a brand
new probe to determine the neutrino mass hierarchy in the detection of galactic
supernova neutrinos. Finally, we discuss the origin of such correlation
patterns and perspectives for further improvement on our results.Comment: 24 pages, 7 figures, 4 table
Discovering Fuzzy Association Rules from Patient's Daily Text Messages to Diagnose Melancholia
With the constant stress from work load and daily life
people may show symptoms of melancholia. However, most
people are reluctant to describe it or may not know that they
already have it. In this paper a novel system is proposed to
discover clues from patientās interaction with psychologist or
from self-recorded voice or text messages. A user friendly
interface is provided for patients to input text messages or record
a voice file by mobile phones or other input devices. A speech-totext
conversion software is used to convert voice mails to simple
text files in advance. Based on the text files, a data mining model
is used to discover frequent keywords mentioned in the text or
speech files. The association rules can be used to help
psychologists diagnose patientsā degree of melancholia.
Experimental results show that the proposed system can
effectively discover melancholia keywords
Magnon-induced non-Markovian friction of a domain wall in a ferromagnet
Motivated by the recent study on the quasiparticle-induced friction of
solitons in superfluids, we theoretically study magnon-induced intrinsic
friction of a domain wall in a one-dimensional ferromagnet. To this end, we
start by obtaining the hitherto overlooked dissipative interaction of a domain
wall and its quantum magnon bath to linear order in the domain-wall velocity
and to quadratic order in magnon fields. An exact expression for the pertinent
scattering matrix is obtained with the aid of supersymmetric quantum mechanics.
We then derive the magnon-induced frictional force on a domain wall in two
different frameworks: time-dependent perturbation theory in quantum mechanics
and the Keldysh formalism, which yield identical results. The latter, in
particular, allows us to verify the fluctuation-dissipation theorem explicitly
by providing both the frictional force and the correlator of the associated
stochastic Langevin force. The potential for magnons induced by a domain wall
is reflectionless, and thus the resultant frictional force is non-Markovian
similarly to the case of solitons in superfluids. They share an intriguing
connection to the Abraham-Lorentz force that is well-known for its causality
paradox. The dynamical responses of a domain wall are studied under a few
simple circumstances, where the non-Markovian nature of the frictional force
can be probed experimentally. Our work, in conjunction with the previous study
on solitons in superfluids, shows that the macroscopic frictional force on
solitons can serve as an effective probe of the microscopic degrees of freedom
of the system.Comment: 13 pages, 2 figure
Genetic testing of sperm donors in China: a survey of current practices
BackgroundThe National Health and Family Planning Commission of China (NHFPCC) issued the āMeasures for the Management of Human Sperm Banks,ā which was revised in 2003 and is still in effect today. One of the standard guidelines is that potential donors undergo laboratory testing to exclude infectious and genetic diseases and karyotype analysis. However, patient demands for donor genetic testing have also increased, and only karyotype analysis to exclude genetic diseases is not sufficient to meet these demands.ObjectiveTo examine donor genetic screening practices at sperm banks in China and to evaluate the qualifications and skills of genetic counselors at the banks.Materials and methodsAn electronic survey was distributed to twenty-seven sperm banks to examine donor genetic screening practices at sperm banks in China and to evaluate the qualifications and skills of genetic counselors at the banks. Twenty-six human sperm banks responded to a 32-question survey about their current practices related to genetic testing of sperm donors.ResultsThe 26 sperm banks reported that all qualified sperm donors undergo karyotype analysis; 22 banks (84.6%) collected three generations of family history from each qualified sperm donor; 10 (38.5%) reported that they attempted to accommodate special requests from donor semen recipients for particular genetic tests. Only 2 of the 26 (7.7%) sperm banks reported that they performed whole-exome sequencing. At all the sperm banks, consent for genetic testing was obtained as part of the overall contract for sperm donors. Nineteen (73.1%) sperm banks had genetic counselors on their staff, while six (23.1%) had no genetic counselors on their staff but had access to genetic counselors at the hospital. Only one (3.8%) sperm bank had no genetic counselors on their staff or at the hospital.ConclusionsThe need for larger scale genetic testing of donors and recipients and an extensive panel of genetic tests specific to the Chinese population. Additionally, professionally trained geneticists must be employed as genetic counsellors so that the results of genetic tests and their implications can be explained to donors
Additive Manufacturing of Complexly Shaped SiC with High Density Via Extrusion-Based Technique ā Effects of Slurry Thixotropic Behavior and 3D Printing Parameters
Additive manufacturing of dense SiC parts was achieved via an extrusion-based process followed by electrical-field assisted pressure-less sintering. The aim of this research was to study the effect of the rheological behavior of SiC slurry on the printing process and quality, as well as the influence of 3D printing parameters on the dimensions of the extruded filament, which are directly related to the printing precision and quality. Different solid contents and dispersant- Darvan 821A concentrations were studied to optimize the viscosity, thixotropy and sedimentation rate of the slurry. The optimal slurry was composed of 77.5 wt% SiC, Y2O3 and Al2O3 powders, 0.25 wt% dispersant and 0.01 wt% defoamer. The printing parameters studied included extrusion pressure, nozzle size, layer height and printing speed; the one that had the most prominent effect on filament width and height was indicated as layer height. The nozzle inner diameter of 1.04 mm, speed of 350 mm/min, layer height of 0.7 mm and extrusion air pressure of 0.31 MPa were the optimal printing parameters. Furthermore, the relationship between the printing parameters and the filament dimensions was successfully predicted by using machine learning and grey system theory. Finally, the relative density of the printed SiC parts sintered at 1900 oC reached 94.7Ā±1.5%
- ā¦