Quasi-two-body decays Bc→D∗h→DπhB_c\to D^*h\to D\pi h in the perturbative QCD

In this work, we investigate the quasi-two-body decays $B_c\to D^*h\to D\pi h$ with $h = (K^0,\pi^0,\eta,\eta^{\prime})$ using the perturbative QCD(PQCD) approach. The description of final state interactions between the $D\pi$ pair is achieved through the two-meson distribution amplitudes(DAs), which are normalized to the time-like form factor. The PQCD predictions on the branching ratios of the quasi-two-body decays $B_c\to D^*h\to D\pi h$ show an obvious hierarchy: $Br(B_{c}^+ \to D^{*+} K^{0}\to D^0\pi^+K^{0})=({5.22}_{-0.74}^{+0.86})\times{10}^{-6}, Br(B_{c}^+ \to D^{*+} \pi^{0}\to D^0\pi^+\pi^{0})=(0.93\pm0.26)\times{10}^{-7}, Br(B_{c}^+ \to D^{*+} \eta\to D^0\pi^+\eta) =({2.83}_{-0.52}^{+0.59})\times{10}^{-8}$ and $Br(B_{c}^+ \to D^{*+} \eta^\prime\to D^0\pi^+\eta^\prime)=({1.89}_{-0.36}^{+0.40})\times{10}^{-8}$. From the invariant mass $m_{D\pi}$-dependence of the decay spectrum for each channel, one can find that the branching fraction is concentrated in a narrow region around the $D^{*}$ pole mass. So one can obtain the branching ratios for the corresponding two-body decays $B_c\to D^{*+}h$ under the narrow width approximation. We find that the branching ratios of the decays $B_c\to D^{*+}h$ are consistent well with the previous PQCD calculations within errors. These predictions will be tested by the future experiments.Comment: 12 pages, 3 figures, accepted for publication in Chin. Phys.

A study on the impact of extreme weather on the poverty vulnerability of farming households—evidence from six counties in the hubei and yunnan provinces of china

By using micro-farm household survey data from six counties in the Hubei and Yunnan provinces, warm days, heavy precipitation, and consecutive dry days were selected as extreme weather measures, and the RClimDex software was used to empirically examine the impacts of extreme weather on farm household poverty vulnerability by setting percentile thresholds to measure extreme weather indicators in each district and county in 2017. Based on the improved Department for International Development sustainable livelihoods analysis framework, the entropy value method was used to synthesize the variables in the farm household sustainable livelihood capacity to examine their mediating effects. The results were as follows: 1) Extreme weather significantly affected farm household poverty vulnerability. Warm days were significantly and negatively related to farmers’ poverty vulnerability, while total heavy precipitation and consecutive dry days were significantly and positively related to farmers’ poverty vulnerability. 2) The impacts of extreme weather on farmers with different vulnerability characteristics varied. 3) The sustainable livelihood capacity of farm households played a partially mediating role in the process of extreme weather indicators of persistent drought index affecting the poverty vulnerability of farm households. 4) As compared to rural households engaged in non-agricultural industries, agricultural production and operation-based farming households were more vulnerable to shocks from extreme weather. Accordingly, we recommended that to improve farmers’ climate resilience, differentiated policies should be adopted according to local conditions; climate-sensitive vulnerable groups should be identified; agricultural insurance coverage should be expanded; farmers should be guided into entrepreneurship; and equalization of public services should be equalized so as to avoid farmers becoming impoverished due to extreme weather

Predictions of Light Hadronic Decays of Heavy Quarkonium 1D_2 States in NRQCD

The inclusive light hadronic decays of 1D_2 heavy quarkonia are studied within the framework of NRQCD at the leading order in $v$ and up to the order of $\alpha_s^3$. With one-loop QCD corrections, the infrared divergences and Coulomb singularities in the decay amplitudes are proved to be absorbed by the renormalization of the matrix elements of corresponding NRQCD operators, and the infrared finite short-distance coefficients are obtained through the matching calculations. By taking the factorization scale to be 2m_Q, the light hadronic decay widths are estimated to be about 274, 4.7, and 8.8 KeV for the $\eta_{c2}, \eta_{b2}$, and $\eta_{b2}'$ respectively. Based on the above estimates, and using the E1 transition width and dipion transition width for the $\eta_{c2}$ estimated elsewhere, we get the total width of $\eta_{c2}$ to be about 660-810 KeV, and the branching ratio of the E1 transition $\eta_{c2}\to\gamma h_c$ to be about (44-54)%, which will be useful in searching for this missing charmonium state through, e.g., the process $\eta_{c2}\to\gamma h_c$ followed by $h_c\to\gamma\eta_c$.Comment: 27 pages, 10 figure

Characteristics of functionalized nano-hydroxyapatite and internalization by human epithelial cell

Hydroxyapatite is the main inorganic component of biological bone and tooth enamel, and synthetic hydroxyapatite has been widely used as biomaterials. In this study, a facile method has been developed for the fabrication of arginine-functionalized and europium-doped hydroxyapatite nanoparticles (Arg-Eu-HAP). The synthesized nanoparticles characterized by transmission electron microscopy, X-ray diffractometry, Fourier transform infrared, and Zeta potential analyzer. Its biological properties with DNA binding, cell toxicity, cell binding and intracellular distribution were tested by agarose gel electrophoresis assay, flow cytometry, and fluorescence microscope and laser scanning confocal microscope. The synthesized Arg-Eu-HAP could effectively bind DNA without any cytotoxicity and be internalized into the cytoplasm and perinuclear of human lung epithelial cells

The conserved aromatic residue W-122 is a determinant of potyviral coat protein stability, replication, and cell-to-cell movement in plants

Coat proteins (CPs) play critical roles in potyvirus cell-to-cell movement. However, the underlying mechanism controlling them remains unclear. Here, we show that substitutions of alanine, glutamic acid, or lysine for the conserved residue tryptophan at position 122 (W-122) in tobacco vein banding mosaic virus (TVBMV) CP abolished virus cell-to-cell movement in Nicotiana benthamiana plants. In agroinfiltrated N. benthamiana leaf patches, both the CP and RNA accumulation levels of three W-122 mutant viruses were significantly reduced compared with those of wild-type TVBMV, and CP accumulated to a low level similar to that of a replication-deficient mutant. The results of polyprotein transient expression experiments indicated that CP instability was responsible for the significantly low CP accumulation levels of the three W-122 mutant viruses. The substitution of W-122 did not affect CP plasmodesmata localization or virus particle formation; however, the substitution significantly reduced the number of virus particles. The wild-type TVBMV CP could complement the reduced replication and abolished cell-to-cell movement of the mutant viruses. When the codon for W-122 was mutated to that for a different aromatic residue, phenylalanine or tyrosine, the resultant mutant viruses moved systemically and accumulated up to 80% of the wild-type TVBMV level. Similar results were obtained for the corresponding amino acids of W-122 in the watermelon mosaic virus and potato virus Y CPs. Therefore, we conclude that the aromatic ring in W-122 in the core domain of the potyviral CP is critical for cell-to-cell movement through the effects on CP stability and viral replication.Peer reviewe