68,913 research outputs found
On the Triality Theory for a Quartic Polynomial Optimization Problem
This paper presents a detailed proof of the triality theorem for a class of
fourth-order polynomial optimization problems. The method is based on linear
algebra but it solves an open problem on the double-min duality left in 2003.
Results show that the triality theory holds strongly in a tri-duality form if
the primal problem and its canonical dual have the same dimension; otherwise,
both the canonical min-max duality and the double-max duality still hold
strongly, but the double-min duality holds weakly in a symmetrical form. Four
numerical examples are presented to illustrate that this theory can be used to
identify not only the global minimum, but also the largest local minimum and
local maximum.Comment: 16 pages, 1 figure; J. Industrial and Management Optimization, 2011.
arXiv admin note: substantial text overlap with arXiv:1104.297
Meter-baseline tests of sterile neutrinos at Daya Bay
We explore the sensitivity of an experiment at the Daya Bay site, with a
point radioactive source and a few meter baseline, to neutrino oscillations
involving one or more eV mass sterile neutrinos. We find that within a year,
the entire 3+2 and 1+3+1 parameter space preferred by global fits can be
excluded at the 3\sigma level, and if an oscillation signal is found, the 3+1
and 3+2 scenarios can be distinguished from each other at more than the 3\sigma
level provided one of the sterile neutrinos is lighter than 0.5 eV.Comment: 4 pages, 5 figures, 1 table. Version to appear in PL
Astronomy: Starbursts near and far
Observations of intensely bright star-forming galaxies both close by and in
the distant Universe at first glance seem to emphasize their similarity. But
look a little closer, and differences emerge.Comment: 6 pages including 1 figur
Generic dark matter signature for gamma-ray telescopes
We describe a characteristic signature of dark matter (DM) annihilation or
decay into gamma-rays. We show that if the total angular momentum of the
initial DM particle(s) vanishes, and helicity suppression operates to prevent
annihilation/decay into light fermion pairs, then the amplitude for the
dominant 3-body final state f^+f^-\gamma has a unique form dictated by gauge
invariance. This amplitude and the corresponding energy spectra hold for
annihilation of DM Majorana fermions or self-conjugate scalars, and for decay
of DM scalars, thus encompassing a variety of possibilities. Within this
scenario, we analyze Fermi LAT, PAMELA and HESS data, and predict a hint in
future Fermi gamma-ray data that portends a striking signal at atmospheric
Cherenkov telescopes (ACTs).Comment: 9 pages, 4 figures. Version to appear in PR
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
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