6,341 research outputs found
Blog Analysis with Fuzzy TFIDF
These days blogs are becoming increasingly popular because it allows anyone to share their personal diary, opinions, and comments on the World Wide Wed. Many blogs contain valuable information, but it is a difficult task to extract this information from a high number of blog comments. The goal is to analyze a high number of blog comments by clustering all blog comments by their similarity based on keyword relevance into smaller groups. TF-IDF weight has been used in classifying documents by measuring appearance frequency of each keyword in a document, but it is not effective in differentiating semantic similarities between words. By applying fuzzy semantic to TF-IDF, TF-IDF becomes fuzzy TF-IDF and has the ability to rank semantic relevancy. Fuzzy VSM can be effective in exploring hidden relationship between blog comments by adapting fuzzy TF-IDF and fuzzy semantic for extending Vector Space Model to fuzzy VSM. Therefore, fuzzy VSM can cluster a high number of blog comments into small number of groups based on document similarity and semantic relevancy
Out-of-Equilibrium Chiral Magnetic Effect at Strong Coupling
We study the charge transports originating from triangle anomaly in
out-of-equilibrium conditions in the framework of AdS/CFT correspondence at
strong coupling, to gain useful insights on possible charge separation effects
that may happen in the very early stages of heavy-ion collisions. We first
construct a gravity background of a homogeneous mass shell with a finite
(axial) charge density gravitationally collapsing to a charged blackhole, which
serves as a dual model for out-of-equilibrium charged plasma undergoing
thermalization. We find that a finite charge density in the plasma slows down
the thermalization. We then study the out-of-equilibrium properties of Chiral
Magnetic Effect and Chiral Magnetic Wave in this background. As the medium
thermalizes, the magnitude of chiral magnetic conductivity and the response
time delay grow. We find a dynamical peak in the spectral function of retarded
current correlator, which we identify as an out-of-equilibrium chiral magnetic
wave. The group velocity of the out-of-equilibrium chiral magnetic wave is
shown to receive a dominant contribution from a non-equilibrium effect, making
the wave moving much faster than in the equilibrium, which may enhance the
charge transports via triangle anomaly in the early stage of heavy-ion
collisions.Comment: 1+35 pages, 8 figures. References added. Published versio
A Radiative Neutrino Mass Model with SIMP Dark Matter
We propose the first viable radiative seesaw model, in which the neutrino
masses are induced radiatively via the two-loop Feynman diagram involving
Strongly Interacting Massive Particles (SIMP). The stability of SIMP dark
matter (DM) is ensured by a discrete symmetry, through which the
DM annihilation rate is dominated by the self-annihilating processes.
The right amount of thermal relic abundance can be obtained with perturbative
couplings in the resonant SIMP scenario, while the astrophysical bounds
inferred from the Bullet cluster and spherical halo shapes can be satisfied. We
show that SIMP DM is able to maintain kinetic equilibrium with thermal plasma
until the freeze-out temperature via the Yukawa interactions associated with
neutrino mass generation.Comment: 19 pages, 8 figures, 2 tables, expanded, new appendix added, new
references added, updated plots, fixed minor typos, matches journal versio
Scalar Dark Matter and Standard Model with Four Generations
We consider a scalar dark matter model, the SM4+D, consisting of the standard
model with four generations (SM4) and a real gauge-singlet scalar called
darkon, D, as the weakly interacting massive particle (WIMP) dark-matter (DM)
candidate. We explore constraints on the darkon sector of the SM4+D from WIMP
DM direct-search experiments, including CDMS II and CoGeNT, and from the decay
of a B meson into a kaon plus missing energy. We find that a sizable portion of
the darkon parameter space is still compatible with the experimental data.
Since the darkon-Higgs interaction may give rise to considerable enhancement of
the Higgs invisible decay mode, the existence of the darkon could lead to the
weakening or evasion of some of the restrictions on the Higgs mass in the
presence of fourth-generation quarks. In addition, it can affect the
flavor-changing decays of these new heavy quarks into a lighter quark and the
Higgs boson, as the Higgs may subsequently decay invisibly. Therefore we also
study these flavor-changing neutral transitions involving the darkon, as well
as the corresponding top-quark decay t -> cDD, some of which may be observable
at the Tevatron or LHC and thus provide additional tests for the SM4+D.Comment: 18 pages, 5 figure
Systematic U(1)_{B-L} Extensions of Loop-Induced Neutrino Mass Models with Dark Matter
We study the gauged U(1)_{B-L} extensions of the models for neutrino masses
and dark matter. In this class of models, tiny neutrino masses are radiatively
induced through the loop diagrams, while the origin of the dark matter
stability is guaranteed by the remnant of the gauge symmetry. Depending on how
the lepton number is violated in the neutrino mass diagrams, these models are
systematically classified. We present a complete list for the one-loop Z_2 and
the two-loop Z_3 neutrino mass models as examples of the classification. These
underlying gauge symmetries and its breaking patterns can be probed at future
high energy colliders by looking at the width of the new gauge boson.Comment: 15 pages, 4 figures, revised to match version published in PR
Exploring X-Ray Lines as Scotogenic Signals
We consider some implications of X-ray lines from certain astronomical
objects as potential effects of dark matter decay in the context of the
scotogenic model, where neutrinos acquire mass radiatively via one-loop
interactions with dark matter. As an example, we focus on the 3.5 keV line
recently detected in the X-ray spectra of galaxy clusters, assuming that it
stands future scrutiny. We explore the scenario in which the line originates
from the slow decay of fermionic dark matter in the model. After obtaining a
number of benchmark points representing the parameter space consistent with the
new data and various other constraints, we make predictions on several
observables in leptonic processes. They include the effective Majorana mass in
neutrinoless double-beta decay, the sum of neutrino masses, and the rate of
flavor-changing decay mu -> e gamma, as well as the cross sections of e+e-
collisions into final states containing nonstandard particles in the model.
These are testable in ongoing or future experiments and thus offer means to
probe the scotogenic scenario studied.Comment: 12 pages, no figures, slightly revised, references added, main
conclusions unchanged, journal versio
A comparative assessment of mortality among the widowers and widows in Taiwan
This paper explores the impact of spousal death on estimated mortality between the widowers and widows among the middle aged and elderly in Taiwan. Subject data is obtained from the Survey of Health and Living Status of the Middle Aged and Elderly in Taiwan, a study conducted in 1996 that encompassed observations 50 years of age and older. Survey data was linked to 1996-2003 national death registry data. Cox proportional hazard model is used to determine the survival rates between the widowers and widows. Main empirical results confirm that the relatively higher mortality hazard associated with being widowhood groups regardless of widowers and widows. Nevertheless, widows face a higher mortality risk than widowers for who compared to their counterparts. In addition, the influences of family and social networks on mortality risk tend to be more important than health status.
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