Intermittent behavior of cosmic mass field revealed by QSO's Ly_alpha forests

The intermittent behavior of the space-scale distribution of Ly$\alpha$ transmitted flux of QSO HS1700+64 has been analyzed via a discrete wavelet transform. We found that there are strong indications of intermittency on scales down to about 10 $h^{-1}$ kpc. These are: 1.) the probability distribution function of the local fluctuations of the flux is significantly long-tailed on small scales, and 2.) the local power spectrum of the flux shows prominent spiky structures on small scales. Moreover, the local power spectrum averaged on regions with different sizes shows similar spiky structures. Therefore, the random mass density field traced by the Ly$\alpha$ forests is rougher on smaller scales, consistent with singular clustering.Comment: Accepted for publication in ApJ Letters, 12 pages, 3 figure

Analysis of the Application of Artificial Intelligence in Medical Imaging

Medical imaging technology is considered one of the most critical diagnostic tools in the clinical analysis, and its imaging results provide medical interventions with the changes of patients' tissues and organs to support the diagnosis. With the development of computer technology, the application of artificial intelligence (AI) technology in clinical diagnosis has become increasingly more widespread. In order to enhance the quality of medical imaging work, this paper mainly analyzes the application effect of AI in medical imaging, further discovering the significance of the application of artificial intelligence in medical imaging

The masses and axial currents of the doubly charmed baryons

The chiral dynamics of the doubly heavy baryons is solely governed by the light quark. In this work, We have derived the chiral corrections to the mass of the doubly heavy baryons up to N$^3$LO. The mass splitting of $\Xi_{cc}$ and $\Omega_{cc}$ at the N$^2$LO depends on one unknown low energy constant $c_7$. With the experimental mass of $\Xi_{cc}(3520)$ as the input, we estimate the mass of $\Omega_{cc}$ to be around 3.678 GeV. Moreover, we have also performed a systematical analysis of the chiral corrections to the axial currents and axial charges of the doubly heavy baryons. The chiral structure and analytical expressions will be very useful to the chiral extrapolations of the future lattice QCD simulations of the doubly heavy baryons.Comment: 10 pages, 2 tables, 3 figure. Accepted by Phys. Rev.

The large-scale rms bulk velocity estimated from QSOs' Lyα\alpha forests

We propose a method for estimating the large-scale rms bulk velocity of the cosmic mass field from the transmitted fluxes of Ly$\alpha$ forests. It is based on two linear relationships on large scales: 1) the relation between the fluctuations of the transmission and the underlying density field, and 2) the relation between the density fluctuations and the peculiar velocity field. We show that, with a multiscale decomposition, the two relations can be effectively employed for predicting the rms bulk velocity. Since QSO's Ly$\alpha$ forest is due to the absorptions of diffusely distributed and photoionized IGM, this method provides an independent estimate of the rms bulk velocity at high redshifts, on large scales, and free from the bias of galaxies. Using the transmitted flux of 60 moderate-resolution QSO spectra, the rms bulk velocity is found to be 230$\pm$50 km s$^{-1}$ around redshift $z=2.25$ on scale 23 h$^{-1}$Mpc, and down to 110$\pm$45 km s$^{-1}$ around $z=3.25$ on scale 92 h$^{-1}$Mpc for an LCDM universe ($\Omega=0.3$ and $\Lambda=0.7$). The results are basically consistent with the linear evolution theory.Comment: 14 pages, 1 figure, ApJ accepte