CLAPA-II, formerly known as CLAPA-T, is being built by Peking University with the support of China’s Ministry of Science and Technology. The main purpose of this device is to explore and verify the ...application performance of a laser-driven particle acceleration beam. For proton therapy, it is desirable to have a highly uniform beam distribution during irradiation. Furthermore, according to experimental results and design experience, low particle current will be one of the main challenges in the application of laser beam acceleration. It is important to improve the efficiency of particle transport to increase the particle current available for applications. In order to improve dose uniformity and maximize transport efficiency, we have made an upgrade to our existing beam dynamics design. The modified design keeps the original characteristics of local achromatic transport, but adds a new section for beam homogenization using octupole fields. This beamline can provide continuously-adjustable beam spots at the target point with diameters from 5 mm to 80 mm and energy dispersion of less than 5%. The set of octupoles enables the beam transport system to provide two selectable distributions, which are similar to a Gaussian distribution and a nearly uniform distribution. The beam parameters required by irradiation are taken as the standard, and the results obtained by beam stacking after homogenization have clear advantages. These advantages can improve both the dose uniformity and the beam utilization rate, thereby mitigating the low average particle current from the laser accelerator.
The Born cross sections of the processes $e^+e^–$ → $ωπ^0$ and $e^+e^–$ → $ωη$ are measured at center-of-mass energies between 3.773 and 4.701 GeV using a total integrated luminosity of 22.7 fb–1 ...collected with the BESIII detector operating at the BEPCII collider. A simple $s^{-n}$ dependence for the continuum process can describe the measured Born cross sections. No significant contributions from the ψ(4160), Y(4230), Y(4360), ψ(4415), Y(4660) resonances are found, which indicates relative small branching fractions for these resonances into the $ωπ^0$ and $ωη$ final states.
We report new measurements of the branching fraction B(Dv), where lis either mu or tau (-> pi), based on 6.32 fbof electron-positron annihilation data collected by the BESIII experiment at six ...center-of-mass energy points between 4.178 and 4.226 GeV. Simultaneously floating the Ds -> mu mu components yields B(D -> tau) = (5.21 +/- 0.25 +/- 0.17) x 102, B(D -> mu mu) (5.35 +/- 0.13 +/- 0.16) x 103, and the ratio of decay widths R = Gamma(D -> tau tau)/Gamma -> mu&m)= 9.73-0.58 +/- 0.36, where the first uncertainties are statistical and the second systematic. No evidence of CP asymmetry is observed in the decay rates Ds +/- -> mu +/- v mu and D +/- -> tau +/-= (+2.9 +/- 4.8 +/- 1.0)%. Constraining our measurement to the Standard Model expectation of lepton universality (R = 9.75), we find the more precise results B(D -> tau = (5.22 +/- 0.10 +/- 0.14) x 10-2and A(+/-) = (-0.1 +/- 1.9 +/- 1.0)%. Combining our results with inputs external to our analysis, we determine the C -> (S) over bar quark mixing matrix element, D+ decay constant, and ratio of the decay constants to be vertical bar V vertical bar = 0.973 +/- 0.009 +/- 0.014, f D+ = 249.9 +/- 2.4 +/- 3.5 MeV, and f D+ / f D = 1.232 +/- 0.035, respectively.
The optimal choice of treatment, with hemodialysis (HD) or peritoneal dialysis (PD), for end-stage renal disease (ESRD) patients, is still controversial. Only a few studies comparing HD and PD have ...been conducted in China, which has the largest number of dialysis patients in the world.
A retrospective cohort study was conducted on ESRD patients who began renal replacement treatment from January 1, 2012 to December 31, 2017 in Guangdong Provincial Hospital of Chinese Medicine. Propensity scoring match was applied to balance the baseline conditions and multivariate Cox regression analysis to compare the mortality between HD and PD patients, and evaluated the correlation between mortality and various baseline characteristics.
A total of 436 HD patients and 501 PD patients were included in this study, and PD patients had better survival than HD patients, but the difference was not statistically significant. For younger ESRD patients (≤60-year-old), the overall survival of PD was better than that of HD, but HD was associated with a lower risk of death in older patients (> 70-year-old). This difference was still significant after adjustment for a variety of confounding factors. Female gender, age at dialysis initiation, cardiovascular disease, cholesterol, and HD were risk factors of all-cause mortality in the younger subgroup, while PD was risk factor in the older subgroup.
PD may be a better choice for younger ESRD patients, and HD for the older patients.
Using the data samples collected in the energy range from 3.773 to 4.600 GeV with the BESIII detector at the BEPCII collider, we measure the dressed cross sections as a function of center-of-mass ...energy for e(+)e(-) -> K+K- pi(+)pi(-) (pi(0)), K+K-K+K- (pi(0)), pi(+)pi(-) pi(+)pi(-) (pi(0)), and p (p) over bar pi(+)pi(-)(pi(0)). The cross sections for e(+)e(-) -> K+K-K+K- pi(0), p (p) over bar pi(+)pi(-)(pi(0)) are the first measurements. Cross sections for the other five channels are much more precise than previous results in this energy region. We also search for charmonium and charmonium-like resonances, such as the Y(4230), decaying into the same final states. We find evidence of the psi(4040) decaying to pi(+)pi(-) pi(+)pi(-) pi(0) with a statistical significance of 3.6 sigma. Upper limits are provided for other decays since no clear signals are observed.
We measure the branching fractions for seven D-s(+) two-body decays to pseudoscalar mesons, by analyzing data collected at root s = 4:178 similar to 4:226 GeV with the BESIII detector at the BEPCII ...collider. The branching fractions are determined to be B(D-s(+) -> K+eta ') = (2:68 +/- 0:17 +/- 0:17 +/- 0:08) x 10(-3), B(D-s(+) -> eta 'pi(+)) = (37:8 +/- 0:4 +/- 2:1 +/- 1:2) x 10(-3), B(D-s(+) -> K+eta) = (1:62 +/- 0:10 +/- 0:03 +/- 0:05) x 10(-3), B(D-s(+) -> eta pi(+)) = (17:41 +/- 0:18 +/- 0:27 +/- 0:54) x 10(-3), B(D-s(+) -> (K+Ks0)) = (15:02 +/- 0:10 +/- 0:27 +/- 0:47) x 10(-3), B(D-s(+) -> K-s(0)pi(+)) = (1:109 +/- 0:034 +/- 0:023 +/- 0:035) x 10(-3), B(D-s(+) -> K+pi(0)) = (0:748 +/- 0:049 +/- 0:018 +/- 0:023) x 10(-3), where the first uncertainties are statistical, the second are systematic, and the third are from external input branching fraction of the normalization mode D-s(+) -> K+K-pi(+). Precision of our measurements is significantly improved compared with that of the current world average values.
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