Proton strangeness form factors in (4,1) clustering configurations

We reexamine a recent result within a nonrelativistic constituent quark model (NRCQM) which maintains that the uuds\bar s component in the proton has its uuds subsystem in P state, with its \bar s in S state (configuration I). When the result are corrected, contrary to the previous result, we find that all the empirical signs of the form factors data can be described by the lowest-lying uuds\bar s configuration with \bar s in P state that has its uuds subsystem in $S$ state (configuration II). Further, it is also found that the removal of the center-of-mass (CM) motion of the clusters will enhance the contributions of the transition current considerably. We also show that a reasonable description of the existing form factors data can be obtained with a very small probability P_{s\bar s}=0.025% for the uuds\bar s component. We further see that the agreement of our prediction with the data for G_A^s at low-q^2 region can be markedly improved by a small admixture of configuration I. It is also found that by not removing CM motion, P_{s\bar s} would be overestimated by about a factor of four in the case when transition dominates over direct currents. Then, we also study the consequence of a recent estimate reached from analyzing the existing data on quark distributions that P_{s\bar s} lies between 2.4-2.9% which would lead to a large size for the five-quark (5q) system, as well as a small bump in both G^s_E+\eta G^s_M and G^s_E in the region of q^2 =< 0.1 GeV^2.Comment: Prepared for The Fifth Asia-Pacific Conference on Few-Body Problems in Physics 2011 in Seoul, South Korea, 22-26 August 201

KAgF3: quasi-one-dimensional magnetism in three-dimensional magnetic ions sublattice

The electronic structure and magnetic properties of the Jahn-Teller-distorted perovskite KAgF3 have been investigated using the full-potential linerized aug- mented plane-wave method. It is found that KAgF3 exhibits significant quasi-one- dimensional antiferromagnetism with the ratio of exchange constant jJ?j (perpen- dicular to the z axis) and J (along the z axis) about 0.04, although the sublattice of magnetic ion is three-dimensional. The strong quasi-one-dimensional antiferromag- netism originates from the C-antiferro-distortive orbital ordering of the Ag2+ 4d9 ions. The orbital ordered antiferromagnetic insulating state in KAgF3 is determined by on-site Coulomb repulsion to a large extent.Comment: 15 pages, 6 figure

A Statistical Study on Photospheric Magnetic Nonpotentiality of Active Regions and Its Relationship with Flares during Solar Cycles 22-23

A statistical study is carried out on the photospheric magnetic nonpotentiality in solar active regions and its relationship with associated flares. We select 2173 photospheric vector magnetograms from 1106 active regions observed by the Solar Magnetic Field Telescope at Huairou Solar Observing Station, National Astronomical Observatories of China, in the period of 1988-2008, which covers most of the 22nd and 23rd solar cycles. We have computed the mean planar magnetic shear angle (\bar{\Delta\phi}), mean shear angle of the vector magnetic field (\bar{\Delta\psi}), mean absolute vertical current density (\bar{|J_{z}|}), mean absolute current helicity density (\bar{|h_{c}|}), absolute twist parameter (|\alpha_{av}|), mean free magnetic energy density (\bar{\rho_{free}}), effective distance of the longitudinal magnetic field (d_{E}), and modified effective distance (d_{Em}) of each photospheric vector magnetogram. Parameters \bar{|h_{c}|}, \bar{\rho_{free}}, and d_{Em} show higher correlation with the evolution of the solar cycle. The Pearson linear correlation coefficients between these three parameters and the yearly mean sunspot number are all larger than 0.59. Parameters \bar{\Delta\phi}, \bar{\Delta\psi}, \bar{|J_{z}|}, |\alpha_{av}|, and d_{E} show only weak correlations with the solar cycle, though the nonpotentiality and the complexity of active regions are greater in the activity maximum periods than in the minimum periods. All of the eight parameters show positive correlations with the flare productivity of active regions, and the combination of different nonpotentiality parameters may be effective in predicting the flaring probability of active regions.Comment: 20 pages, 5 figures, 4 tables, accepted for publication in Solar Physic

Born-Infeld Type Phantom Model in the ω−ω′\omega-\omega' Plane

In this paper, we investigate the dynamics of Born-Infeld(B-I) phantom model in the $\omega-\omega'$ plane, which is defined by the equation of state parameter for the dark energy and its derivative with respect to $N$(the logarithm of the scale factor $a$). We find the scalar field equation of motion in $\omega-\omega'$ plane, and show mathematically the property of attractor solutions which correspond to $\omega_\phi\sim-1$, $\Omega_\phi=1$, which avoid the "Big rip" problem and meets the current observations well.Comment: 6 pages, 3 figures, some references adde

Statefinder Diagnostic for Dilaton Dark Energy

Statefinder diagnostic is a useful method which can differ one dark energy model from the others. The Statefinder pair $\{r, s\}$ is algebraically related to the equation of state of dark energy and its first time derivative. We apply in this paper this method to the dilaton dark energy model based on Weyl-Scaled induced gravitational theory. We investigate the effect of the coupling between matter and dilaton when the potential of dilaton field is taken as the Mexican hat form. We find that the evolving trajectory of our model in the $r-s$ diagram is quite different from those of other dark energy models.Comment: 6 pages, 4 figures, type errors corrected, reference no. changed, accepted by Astrophysics and Space Scienc

Fuyuanperleidus dengi Geng et. al. 2012 (Osteichthyes, Actinopterygii) from the Middle Triassic of Yunnan Province, South China

Two well preserved specimens of Fuyuanperleidus dengi Geng et al., 2012 are described from the Upper Member of the Guanling Formation (Pelsonian, Anisian, Middle Triassic) in Luoping County, Yunnan Province, South China. The attribution to Perleidiformes is confirmed according to a combination of features such as the general skull pattern, with the large preoperculum showing a prominent infraorbital process, the maxilla with deep posterior region and a dentition made of long and stout peg-like teeth with an acuminate apex, the deep mid-lateral flank scales and the caudal fin with epaxial fin rays. However, this taxon shows an unique arrangement of the squamation (here considered as autapomorphy) given by the insertion of several scales in each vertical row posterior to the pelvic fin, just below the scales carrying the lateral line, when their depth decreases abruptly. Owing to this unique character, and in spite of the very recent description of this genus, the authors considered necessary the erection of a new family, Fuyuanperleididae offering also new insights on the evolutionary trends and morphological specializations of the "subholosteans. A cladistic analysis of the well known perleidiformes, with this taxon included, supports a possible monophyly of the order, and matches well the paleobiogeographic relationships of the Gondwana fresh-water taxa. The specialized deep-bodied Gondwana and Tethyan perleidiformes are independently evolved, ascertained by the parsimony analysis

A quantitative and qualitative study on the neuropsychiatric sequelae of acutely ill COVID-19 inpatients in isolation facilities

10.1038/s41398-020-01039-2Translational Psychiatry10135