Aim: Thalassaemia is a good candidate disease for control by preventive genetic programmes in developing countries. Accurate population frequency data are needed for planning the control of ...thalassaemia in the high risk Guangdong Province of southern China. Methods: In total, 13 397 consecutive samples from five geographical areas of Guangdong Province were analysed for both haematological and molecular parameters. Results: There was a high prevalence of carriers of α thalassaemia (8.53%), β thalassaemia (2.54%), and both α and β thalassaemia (0.26%). Overall, 11.07% of the population in this area were heterozygous carriers of α and β thalassaemia. The mutation spectrum of α and β thalassaemia and its constitution were fully described in this area. This study reports the true prevalence of silent α thalassaemia in the southern China population for the first time. In addition, two novel mutations that give rise to α thalassaemia, one deletion resulting in β thalassaemia, and a rare deletion (−−THAI allele) previously unreported in mainland China were detected. The frequency of the most common mutation, the Southeast Asian type of deletion (−−SEA, accounting for 48.54% of all α thalassaemias) was similar to the total of two α+ thalassaemia deletions (−α3.7 and −α4.2, accounting for 47.49% of α thalassaemia). Conclusion: Both α and β thalassaemia are widely distributed in Guangdong Province of China. The knowledge gained in this study will enable the projected number of pregnancies at risk to be estimated and a screening strategy for control of thalassaemia to be designed in this area.
Using data samples with a total integrated luminosity of 20.1 fb−1 collected by the BESIII detector operating at the BEPCII collider, the cross section of the process e+ e− → π+ π− ψ ( 3686 ) is ...measured at center-of-mass energies between 4.0076 and 4.6984 GeV. The measured cross section is consistent with previous results, and with much improved precision. A fit to the measured energy-dependent cross section, which includes three Breit-Wigner functions and a nonresonant contribution, confirms the existence of the charmonium-like states Y (4220), Y (4390), and Y (4660). This is the first observation of the Y (4660) at the BESIII experiment.
Based on 4.4 fb -1 of e + e - annihilation data collected at the center-of-mass energies between 4.60 and 4.70 GeV with the BESIII detector at the BEPCII collider, the pure W-boson-exchange decay Λ c ...+ → Ξ 0 K + is studied with a full angular analysis. The corresponding decay asymmetry is measured for the first time to be α Ξ 0 K + = 0.01 ± 0.16(stat) ± 0.03(syst). This result reflects the noninterference effect between the S- and P-wave amplitudes. The phase shift between S- and P-wave amplitudes has two solutions, which are δ p - δ s = -1.55 ± 0.25(stat) ± 0.05(syst) rad or 1.59 ± 0.25(stat) ± 0.05(syst) rad.
The singly Cabibbo-suppressed decay Lambda(+)(c) -> n pi(+) e is observed for the first time with a statistical significance of 7.3 sigma by using 3.9 fb(-1) of e(+)e(-) collision data collected ...at center-of-mass energies between 4.612 and 4.699 GeV with the BESIII detector at BEPCII. The branching fraction of Lambda(+)(c) -> n pi(+) is measured to be (6.6 +/- 1.2(stat) 0.4(syst)) x 10(-4). By taking the upper limit of branching fractions of Lambda(+)(c) -> n pi(+) from the Belle experiment, the ratio of branching fractions between Lambda(+)(c) -> n pi(+) and Lambda(+)(c) -> p pi(0) is calculated to be larger than 7.2 at the 90% confidence level, which disagrees with most predictions of the available phenomenological models. In addition, the branching fractions of the Cabibbo-favored decays Lambda(+)(c) -> Lambda pi(+) and Lambda(+)(c)-> Sigma(0)(pi+) are measured to be (1.31 +/- 0.08(stat) +/- 0.05(syst)) x 10(-2) and (1.22 +/- 0.08(stat) +/- 0.07(syst)) x 10(-2), respectively, which are consistent with previous results.
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