Probing dark matter particles at CEPC

We investigate the capability of the future electron collider CEPC in probing the parameter space of several dark matter models, including millicharged dark matter models, $Z'$ portal dark matter models, and effective field theory dark matter models. In our analysis, the monophoton final state is used as the primary channel to detect dark matter models at CEPC. To maximize the signal to background significance, we study the energy and angular distributions of the monophoton channel arising from dark matter models and from the standard model to design a set of detector cuts. For the $Z'$ portal dark matter, we also analyze the $Z'$ boson visible decay channel which is found to be complementary to the monophoton channel in certain parameter space. The CEPC reach in the parameter space of dark matter models is also put in comparison with Xenon1T. We find that CEPC has the unprecedented sensitivity to certain parameter space for the dark matter models considered; for example, CEPC can improve the limits on millicharge by one order of magnitude than previous collider experiments for ${\cal O}(1)-100$ GeV dark matter.Comment: 21 pages, 31 figure

(5-Bromo-2-methyl­phen­yl)(4-eth­oxy­phen­yl)methanone

In the title compound, C16H15BrO2, the dihedral angle between the benzene rings is 68.5 (2)°. In the crystal structure, mol­ecules are linked by weak C—H⋯O hydrogen bonds into chains parallel to the b axis

Research on the relation Between the Self-Leadership and Work Engagement of the Primary and Junior School Headmaster

Know about the work engagement of the primary and middle school headmaster and its influence factors to provide a basis to improve it. Use the self-leadership questionnaires and work engagement scales to conduct a questionnaire survey among 220 primary and middle school headmasters. The self-leadership ability and work engagement of the primary and middle school headmaster are both above the average level; except that there is no significant correlation between self-award or self-punishment dimension and contribution or between self-award and concentration, there exist significant correlations between all the dimensions of self-leadership and those of work engagement of the primary and middle school headmaster; It is discovered with the multiple stepwise regression analysis that the prediction of the two factors goal setting and job inner award entered in the regression equation for work engagement reaches 16.6%. A clear job objective, emphasis on the value of the job itself，neglect of the disappointing side in the job and to think about its positive meaning increase the self-leadership ability of the primary and middle school headmaster and finally improve his or her work engagement as well

Caffeic Acid Phenethyl Ester (CAPE) mediated decrease in metastasis of colon cancer cells: an in vitro and in vivo study

Background: Caffeic acid phenethyl ester (CAPE) is a phytochemically active component obtained from honeybee hive propolis. CAPE has been reported to show antimitogenic, anticancer, and other beneficial medicinal properties. Many of its activities have been reported to be mediated by inhibiting levels of matrix metalloproteinase, that is, MMP-2 and MMP-9. We hypothesize the effect of CAPE on the metastasis of colon cancer cells in both in vitro and in vivo.Methods: Cell migration, motility, invasion were evaluated also expression of protein and matrix metalloproteinases (MMPs) such as MMP-2 and MMP-9 were measured in SW-480 cancer cells in vitro. The cells were exposed to Phorbol 12-myristate 13-acetate (PMA) and were treated with various concentration of CAPE.Results: The treatment of CAPE caused significant decrease (P<0.05) in both cell motility and invasion. The treatment of CAPE inhibited activity of MMP-2 and MMP-9 and their protein with increasing dose in SW-480 cancerous cells. Antimetastatic activity was evaluated in vivo in BALB/c mice by injecting them with CT-26 mouse colon cancer cells via tail vein and were treated with CAPE (20 mg/kg) orally for 21 days. The CAPE treatment significantly (P<0.05) reduced count of pulmonary nodules. The mice showed decreased plasma MMP-2 and MMP-9 activity after 21 days treatment with CAPE.Conclusion: The study suggested beneficial role of CAPE in preventing invasion of colon cancer and metastasis via MMP- 2 and MMP-9 mediated pathway.Keywords: CAPE, colon cancer, SW-480, CT-26, anti-metastati

Spectroscopic Study of Globular Clusters in the Halo of M31 with Xinglong 2.16m Telescope II: Dynamics, Metallicity and Age

(Abridged) We performed the spectroscopic observations of 11 confirmed GCs in M31 with the Xinglong 2.16m telescope and we mainly focus on the fits method and the metallicity gradient for the M31 GC sample. We analyzed and discussed more about the dynamics, metallicity and age, and their distributions as well as the relationships between these parameters. Eight more confirmed GCs in the halo of M31 were observed, most of which lack the spectroscopic information before. These star clusters are located far from the galactic center at a projected radius of ~14 to ~117 kpc. The Lick absorption-line indices and the radial velocities have been measured and ages, metallicities [Fe/H] and alpha-element [alpha/Fe] have also been fitted by comparing the observed spectral feature indices and Thomas et al.SSP model. Our results show that most of the star clusters of our sample are older than 10 Gyr except B290 ~5.5 Gyr, and most of them are metal-poor with the metallicity [Fe/H]<-1, suggesting that these clusters were born at the early stage of the galaxy's formation. We find that the metallicity gradient for the outer halo clusters with r_p>25 kpc may not exist with a slope of -0.005+-0.005 dex kpc^-1. We also find that the metallicity is not a function of age for the GCs with age < 7 Gyr while for the old GCs with age >7 Gyr there seems to be a trend that the older ones have lower metallicity. Besides, We plot metallicity distributions with the largest sample of M31 GCs so far and it shows the bimodality is not significant and the number of the metal-poor and metal-rich groups becomes comparable. The spatial distributions shows that the metal-rich group is more centrally concentrated while the metal-poor group is occupy a more extended halo and the young population is centrally concentrated while the old population is more extended spatially to the outer halo.Comment: 17 pages, 10 figures and 6 tables. Accepted for publication in RA