16,637 research outputs found
Study of and decays
We study the charmless two-body
and three-body decays. We obtain to agree with the
recent LHCb measurement. However, we find that is unable to explain the
LHCb observation of , which implies the possibility for other
contributions, such as that from the resonant decay with as a higher-wave baryon state. For
, we show that ,
which are consistent with the current data of , respectively. Our results also support the relation of ,
given by the previous study.Comment: 8 pages, 1 figure, revised version accepted by EPJ
Exploring Deep Space: Learning Personalized Ranking in a Semantic Space
Recommender systems leverage both content and user interactions to generate
recommendations that fit users' preferences. The recent surge of interest in
deep learning presents new opportunities for exploiting these two sources of
information. To recommend items we propose to first learn a user-independent
high-dimensional semantic space in which items are positioned according to
their substitutability, and then learn a user-specific transformation function
to transform this space into a ranking according to the user's past
preferences. An advantage of the proposed architecture is that it can be used
to effectively recommend items using either content that describes the items or
user-item ratings. We show that this approach significantly outperforms
state-of-the-art recommender systems on the MovieLens 1M dataset.Comment: 6 pages, RecSys 2016 RSDL worksho
Differential expression of early viral gene BmORF51 in Bombyx mori nucleopolyhedrovirus infection of resistant and susceptible silkworms
Open reading frame 51 of Bombyx mori nucleopolyhedrovirus (Bm51) is a homologue of autographa californica multiple NPV ORF63. In this study, the expression profiles of Bm51 in the resistant strain NB and the susceptible strain 306 were characterized, and Bm51 gene was amplified from BmNPV genomic DNA by polymerase chain reaction (PCR) and cloned into Escherichia coli expression vector pET-30a (+). The recombinant His-tagged Bm51 protein was expressed in E. coli BL21 (DE3) and purified by metal chelating affinity chromatography to produce antibodies against Bm51 protein. The amino acid sequence of recombinant protein was confirmed by mass spectroscopic analysis. The transcription and protein product of early viral gene, Bm51, was detected at 6 h post-infection (p.i.) in resistant strain NB by quantitative real-time (qRT)-PCR and western blotting, and the expression of Bm51 in NB reached the maximal level at 36 h p.i. in NB, and then gradually decreased to undetectable level at 72 h p.i. In contrast, the Bm51 protein was undetectable until 12 h p.i. in susceptible strain 306 and the expression of Bm51 progressively increased during the 72 h post-infection
Topologically protected one-dimensional electronic states in group IV two-dimensional Dirac materials
In this report we give a brief introduction on the occurrence of
topologically protected one-dimensional electronic states in group IV
two-dimensional graphene-like materials. We discuss the effect of spin-orbit
coupling on the electronic band structure and show that these materials are
potential candidates to exhibit the quantum spin Hall effect. The quantum spin
Hall effect is characterized by a gapped interior and metallic
counter-propagating spin-polarized topologically protected edges states. We
also elaborate on the electric-field induced formation of a hexagonal network
of one-dimensional topologically protected electronic states in small-angle
twisted bilayer graphene.Comment: These are lecture notes meant for undergraduate and graduate physics
students. This manuscript will not be submitted for publication. Pages: 21.
Figures: 1
Parametric Experimental Study of Ultra-Short Stud Connections for Lightweight Steel–UHPC Composite Bridges
This paper reports on double shear push-out tests conducted on steel-to-ultra-high-performance concrete (UHPC) connections based on studs of 30- or 22-mm diameter in slabs of 35, 55, or 150 mm thickness. The results show that with an increase in stud diameter, the longitudinal shear strength has improved by 25% and 94% for ultra-short and long studs (of aspect ratios below and equal to 4.0), respectively. For short studs, both the aspect ratio and concrete cover greatly influenced failure by partial stud fracture or UHPC pryout, while the diameter governed failure behavior for long studs. Decreases in aspect ratio and cover thickness caused shear resistance to drop by 40% and 7%, respectively, for 30- and 22-mm diameter studs. Regression analyses show that the shear strength, slip stiffness, and ductility of the connections are exponential, sinusoidal, and polynomial functions, respectively, of the stud aspect ratio. The ultra-short stud–UHPC connections are 62% stiffer in slip than their normal concrete counterparts. Future work should entail fatigue testing of the connections
XMM-Newton Spectra of Intermediate-Mass Black Hole Candidates: Application of a Monte-Carlo Simulated Model
We present a systematic spectral analysis of six ultraluminous X-ray sources
(NGC1313 X-1/X-2, IC342 X-1, HoIX X-1, NGC5408 X-1 and NGC3628 X-1) observed
with XMM-Newton Observatory. These extra-nuclear X-ray sources in nearby
late-type galaxies have been considered as intermediate-mass black hole
candidates. We have performed Monte-Carlo simulations of Comptonized
multi-color black-body accretion disks. This unified and self-consistent
spectral model assumes a spherically symmetric, thermal corona around each disk
and accounts for the radiation transfer in the Comptonization. We find that the
model provides satisfactory fits to the XMM-Newton spectra of thesources. The
characteristic temperatures of the accretion disks (T_in), for example, are in
the range of ~ 0.05-0.3 keV, consistent with the intermediate-mass black hole
interpretation. We find that the black hole mass is typically about a few times
10^3 M_\odot and has an accretion rate ~ 10^{-6} - 10^{-5} M_\odot yr^{-1}. For
the spectra considered here, we find that the commonly used multi-color
black-body accretion disk model with an additive power law component, though
not physical, provides a good mathematical approximation to the Monte-Carlo
simulated model. However, the latter model provides additional constraints on
the properties of the accretion systems, such as the disk inclination angles
and corona optical depths.Comment: 23 pages, 4 figures, 5 tables. ApJ accepted, July 2004 issu
X-ray and UV spectroscopy of Galactic diffuse hot gas along the LMC X--3 sight line
We present Suzaku spectra of X-ray emission in the fields just off the LMC
X-3 sight line. OVII, OVIII, and NeIX emission lines are clearly detected,
suggesting the presence of an optically thin thermal plasma with an average
temperature of 2.4E6. This temperature is significantly higher than that
inferred from existing X-ray absorption line data obtained with Chandra grating
observations of LMC X-3, strongly suggesting that the gas is not isothermal. We
then jointly analyze these data to characterize the spatial and temperature
distributions of the gas. Assuming a vertical exponential Galactic disk model,
we estimate the gas temperature and density at the Galactic plane and their
scale heights as 3.6(2.9, 4.7)E6 K and 1.4(0.3, 3.4)E-3 cm^{-3} and 1.4(0.2,
5.2) kpc and kpc, respectively. This characterization can
account for all the \ovi line absorption, as observed in a FUSE spectrum of LMC
X-3, but only predicts less than one tenth of the OVI line emission intensity
typically detected at high Galactic latitudes. The bulk of the OVI emission
most likely arises at interfaces between cool and hot gases.Comment: 10 pages, 7 figures, 3 tables, accepted for publication in ApJ, 200
Direct CP and T Violation in Baryonic B Decays
We review the direct CP and T violation in the three-body baryonic B decays
in the standard model. In particular, we emphasize that the direct CP violating
asymmetry in is around 22% and the direct
violating asymmetry in \bar B^0 \ra \Lambda \bar p \pi^+ can be as large as
12%, which are accessible to the current B factories at KEK and SLAC as well as
SuperB and LHCb.Comment: 6 pages, Talk given at 4th International Conference on Flavor Physics
(ICFP 2007), Beijing, China, 24-28 Sep 200
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