Hall Effect in the coma of 67P/Churyumov-Gerasimenko

Magnetohydrodynamics simulations have been carried out in studying the solar wind and cometary plasma interactions for decades. Various plasma boundaries have been simulated and compared well with observations for comet 1P/Halley. The Rosetta mission, which studies comet 67P/Churyumov-Gerasimenko, challenges our understanding of the solar wind and comet interactions. The Rosetta Plasma Consortium observed regions of very weak magnetic field outside the predicted diamagnetic cavity. In this paper, we simulate the inner coma with the Hall magnetohydrodynamics equations and show that the Hall effect is important in the inner coma environment. The magnetic field topology becomes complex and magnetic reconnection occurs on the dayside when the Hall effect is taken into account. The magnetic reconnection on the dayside can generate weak magnetic filed regions outside the global diamagnetic cavity, which may explain the Rosetta Plasma Consortium observations. We conclude that the substantial change in the inner coma environment is due to the fact that the ion inertial length (or gyro radius) is not much smaller than the size of the diamagnetic cavity.Comment: 23 pages, 6 figur

Spin filtering and magnetoresistance in ballistic tunnel junctions

We theoretically investigate magnetoresistance (MR) effects in connection with spin filtering in quantum-coherent transport through tunnel junctions based on non-magnetic/semimagnetic heterostructures. We find that spin filtering in conjunction with the suppression/enhancement of the spin-dependent Fermi seas in semimagnetic contacts gives rise to (i) spin-split kinks in the MR of single barriers and (ii) a robust beating pattern in the MR of double barriers with a semimagnetic well. We believe these are unique signatures for quantum filtering.Comment: Added references + corrected typo

Towards the demonstration of photon-photon collision with compact lasers

We report a proposal to observe the two-photon Breit-Wheeler process in plasma driven by compact lasers. A high charge electron bunch can be generated from laser plasma wakefield acceleration when a tightly focused laser pulse transports in a sub-critical density plasma. The electron bunch scatters with the laser pulse coming from the opposite direction and results the emitting of high brilliance X-ray pulses. In a three-dimensional particle-in-cell simulation with a laser pulse of $\sim$10 J, one could produce a X-ray pulse with photon number higher than $3\times10^{11}$ and brilliance above $1.6\times 10^{23}$ photons/s/mm$^2$/mrad$^2$/0.1$\%$BW at 1 MeV. The X-ray pulses collide in the plasma and create more than $1.1\times 10^5$ electron-positron pairs per shot. It is also found that the positrons can be accelerated transversely by a transverse electric field generated in the plasma, which enables the safe detection in the direction away from the laser pulses. This proposal which has solved key challenges in laser driven photon-photon collision could demonstrate the two-photon Breit-Wheeler process on a much more compact device in a single shot

Sommerfeld's quantum condition of action and the spectra of Schwarzschild black hole

If the situation of quantum gravity nowadays is nearly the same as that of the quantum mechanics in it's early time of Bohr and Sommerfeld, then a first step study of the quantum gravity from Sommerfeld's quantum condition of action might be helpful. In this short paper the spectra of Schwarzschild black hole(SBH) in quasi-classical approach of quantum mechanics is given. We find the quantum of area, the quantum of entropy and the Hawking evaporation will cease as the black hole reaches its ground state.Comment: 7 pages, no figures, submitted to Classical and Quantum Gravit

CDK-dependent nuclear localization of B-Cyclin Clb1 promotes FEAR activation during meiosis I in budding yeast

Cyclin-dependent kinases (CDK) are master regulators of the cell cycle in eukaryotes. CDK activity is regulated by the presence, post-translational modification and spatial localization of its regulatory subunit cyclin. In budding yeast, the B-cyclin Clb1 is phosphorylated and localizes to the nucleus during meiosis I. However the functional significance of Clb1's phosphorylation and nuclear localization and their mutual dependency is unknown. In this paper, we demonstrate that meiosis-specific phosphorylation of Clb1 requires its import to the nucleus but not vice versa. While Clb1 phosphorylation is dependent on activity of both CDK and polo-like kinase Cdc5, its nuclear localization requires CDK but not Cdc5 activity. Furthermore we show that increased nuclear localization of Clb1 during meiosis enhances activation of FEAR (Cdc Fourteen Early Anaphase Release) pathway. We discuss the significance of our results in relation to regulation of exit from meiosis I

miRNA-99b-5p Targets FZD8 to Inhibit Non-Small Cell Lung Cancer Proliferation, Migration and Invasion [Retraction]

Liu R, Chen Y, Shou T, Hu J, Qing C. Onco Targets Ther. 2019;12:2615–2621. We, the Editor and Publisher of the journal OncoTargets and Therapy, have retracted the following article. Following publication of the article, concerns were raised about the duplication of images from Figures 2 and 4 with images from unrelated articles. Specifically, Images for Figure 2C and 2D have been duplicated with images for Figure 2d and 2e from Jiang N, Jiang X, Chen Z, et al. MiR-203a-3p suppresses cell proliferation and metastasis through inhibiting LASP1 in nasopharyngeal carcinoma. J Exp Clin Cancer Res. 2017;36:138. https://doi.org/10.1186/s13046-017-0604-3 and Figure 3C from Liu B, Li G, Zhang Z, Wu H. RETRACTED: Influence of miR-376c-3p/SYF2 Axis on the Progression of Gastric Cancer. Technology in Cancer Research & Treatment. 2019;18. doi:10.1177/1533033819874808. Images from Figure 4D have been duplicated with images for Figures 2e and 3e from Jiang N, et al (2017). The authors responded to our queries but were unable to provide a satisfactory explanation for the duplicated images or provide satisfactory data for the study. As verifying the validity of published work is core to the integrity of the scholarly record, the Publisher and Editor requested to retract the article and the authors agree with this. We have been informed in our decision-making by our editorial policies and COPE guidelines. The retracted article will remain online to maintain the scholarly record, but it will be digitally watermarked on each page as “Retracted”