9,968 research outputs found
Exotic , and states
After constructing the possible and
tetraquark interpolating currents in a systematic way, we
investigate the two-point correlation functions and extract the corresponding
masses with the QCD sum rule approach. We study the ,
and systems with various isospins . Our numerical analysis indicates that the masses of doubly-bottomed
tetraquark states are below the threshold of the two bottom mesons, two bottom
baryons and one doubly bottomed baryon plus one anti-nucleon. Very probably
these doubly-bottomed tetraquark states are stable.Comment: 37 pages, 2 figure
A NEURO-FUZZY MODEL WITH SEER-SEM FOR SOFTWARE EFFORT ESTIMATION
Software effort estimation is a critical part of software engineering. Although many techniques and algorithmic models have been developed and implemented by practitioners, accurate software effort prediction is still a challenging endeavor. In order to address this issue, a novel soft computing framework was developed by previous researchers. Our study utilizes this novel framework to describe an approach combining the neuro-fuzzy technique and the System Evaluation and Estimation of Resource Software Estimation Model (SEER-SEM) effort estimation algorithm. By introducing the neuro-fuzzy technique, this proposed model utilizes positive characteristics such as learning ability, decreased sensitivity, effective generalization, and knowledge integration. Moreover, our study assesses the performance of the proposed model by designing and conducting evaluation with published project and industrial data. After analyzing the performance of our model in comparison to the SEER-SEM effort estimation algorithm alone, the proposed model demonstrates the ability of improving the estimation accuracy, especially in its ability to reduce the large Magnitude of Relative Error (MRE). Furthermore, the results of this research also indicate that the general neuro-fuzzy framework can function with various algorithmic models for improving the performance of software effort estimation
molecule interpretation of
We have used QCD sum rules to study the newly observed charged state
as a hidden-charm molecular state with the quantum
numbers . Using a molecular interpolating
current, we have calculated the two-point correlation function and the spectral
density up to dimension eight at leading order in . The extracted
mass is GeV. This result is compatible with the observed
mass of within the errors, which implies a possible molecule
interpretation of this new resonance. We also predict the mass of the
corresponding hidden-bottom molecular state:
GeV.Comment: 6 pages, 5 figures. Version appears in Eur. Phys. J.
Possible Exotic State
We study the possible exotic states with using the
tetraquark interpolating currents with the QCD sum rule approach. The extracted
masses are around 4.85 GeV for the charmonium-like states and 11.25 GeV for the
bottomomium-like states. There is no working region for the light tetraquark
currents, which implies the light state may not exist below 2 GeV.Comment: 13 pages, 11 figures, 2 table
Star-forming Main Sequence of Giant Low Surface Brightness Galaxies
Giant Low Surface Brightness Galaxies (GLSBGs) are fundamentally distinct
from normal galaxies (LSBGs) in star formation and evolution. In this work, we
collected 27 local GLSBGs. They have high stellar masses (M*>10^10 Msolar) and
low SFRs. With the specific SFRs lower than the characteristic value of the
local star-forming (SF) galaxies of M*=10^10 Msolar(sSFR < 0.1 Gyr^-1), GLSBGs
deviate from the SF main sequence (MS) defined for local SFGs respectively by
E07 and S16 at the high M* regime. They are HI-rich systems with HI gas mass
fractions (fHI) higher than the S16 MS galaxies, but have little molecular gas
(H2), implying a low efficiency of HI-to-H2 transition due to the low HI
surface densities that are far lower than the minimum of 6 - 8 Msolar pc^-2
required for shielding the formed H2 from photodissociation. For GLSBGs, the
inner, bulge-dominated part with lower SFRs and higher M* is the main force
pulling the entire GLSBG off from the MS, while the outer, disk-dominated part
with relatively higher SFRs and lower M* reduces the deviations from the MS.
For some cases, the outer, disk-dominated parts even tend to follow the MS. In
the aspect of NUV - r versus g - r colors, the outer, disk-dominated parts are
blue and behave similarly to the normal star-forming galaxies while the inner,
bulge-dominated parts are in statistics red, indicating an inside-out star
formation mechanism for the GLSBGs. They show few signs of external
interactions in morphology, excluding the recent major merger scenario.Comment: 17 pages, 9 figures, accepted for publication in Ap
Decreasing the uncertainty of atomic clocks via real-time noise distinguish
The environmental perturbation on atoms is the key factor restricting the
performance of atomic frequency standards, especially in long term scale. In
this letter, we demonstrate a real-time noise distinguish operation of atomic
clocks. The operation improves the statistical uncertainty by about an order of
magnitude of our fountain clock which is deteriorated previously by extra
noises. The frequency offset bring by the extra noise is also corrected. The
experiment proves the real-time noise distinguish operation can reduce the
contribution of ambient noises and improve the uncertainty limit of atomic
clocks.Comment: 5 pages, 4 figures, 1 tabl
Müller Glial Cells Participate in Retinal Waves via Glutamate Transporters and AMPA Receptors
Retinal waves, the spontaneous patterned neural activities propagating among developing retinal ganglion cells (RGCs), instruct the activity-dependent refinement of visuotopic maps. Although it is known that the wave is initiated successively by amacrine cells and bipolar cells, the behavior and function of glia in retinal waves remain unclear. Using multiple in vivo methods in larval zebrafish, we found that Müller glial cells (MGCs) display wave-like spontaneous activities, which start at MGC processes within the inner plexiform layer, vertically spread to their somata and endfeet, and horizontally propagate into neighboring MGCs. MGC waves depend on glutamatergic signaling derived from bipolar cells. Moreover, MGCs express both glia-specific glutamate transporters and the AMPA subtype of glutamate receptors. The AMPA receptors mediate MGC calcium activities during retinal waves, whereas the glutamate transporters modulate the occurrence of retinal waves. Thus, MGCs can sense and regulate retinal waves via AMPA receptors and glutamate transporters, respectively
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