1,444 research outputs found

    Disparities and risks of sexually transmissible infections among men who have sex with men in China: a meta-analysis and data synthesis.

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    BACKGROUND: Sexually transmitted infections (STIs), including Hepatitis B and C virus, are emerging public health risks in China, especially among men who have sex with men (MSM). This study aims to assess the magnitude and risks of STIs among Chinese MSM. METHODS: Chinese and English peer-reviewed articles were searched in five electronic databases from January 2000 to February 2013. Pooled prevalence estimates for each STI infection were calculated using meta-analysis. Infection risks of STIs in MSM, HIV-positive MSM and male sex workers (MSW) were obtained. This review followed the PRISMA guidelines and was registered in PROSPERO. RESULTS: Eighty-eight articles (11 in English and 77 in Chinese) investigating 35,203 MSM in 28 provinces were included in this review. The prevalence levels of STIs among MSM were 6.3% (95% CI: 3.5-11.0%) for chlamydia, 1.5% (0.7-2.9%) for genital wart, 1.9% (1.3-2.7%) for gonorrhoea, 8.9% (7.8-10.2%) for hepatitis B (HBV), 1.2% (1.0-1.6%) for hepatitis C (HCV), 66.3% (57.4-74.1%) for human papillomavirus (HPV), 10.6% (6.2-17.6%) for herpes simplex virus (HSV-2) and 4.3% (3.2-5.8%) for Ureaplasma urealyticum. HIV-positive MSM have consistently higher odds of all these infections than the broader MSM population. As a subgroup of MSM, MSW were 2.5 (1.4-4.7), 5.7 (2.7-12.3), and 2.2 (1.4-3.7) times more likely to be infected with chlamydia, gonorrhoea and HCV than the broader MSM population, respectively. CONCLUSION: Prevalence levels of STIs among MSW were significantly higher than the broader MSM population. Co-infection of HIV and STIs were prevalent among Chinese MSM. Integration of HIV and STIs healthcare and surveillance systems is essential in providing effective HIV/STIs preventive measures and treatments. TRIAL REGISTRATION: PROSPERO NO: CRD42013003721

    Search for an axion-like particle in J/ψJ/\psi radiative decays

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    We search for an axion-like particle (ALP) aa through the process ψ(3686)→π+π−J/ψ\psi(3686)\rightarrow\pi^+\pi^-J/\psi, J/ψ→γaJ/\psi\rightarrow\gamma a, a→γγa\rightarrow\gamma\gamma in a data sample with (2708.1±14.5)×106(2708.1\pm14.5)\times10^6 ψ(3686)\psi(3686) events collected by the BESIII detector. No significant ALP signal is observed over the expected background, and the upper limits on the branching fraction of the decay J/ψ→γaJ/\psi\rightarrow\gamma a and the ALP-photon coupling constant gaγγg_{a\gamma\gamma} are set at the 95\% confidence level in the mass range of 0.165\leq m_a\leq2.84\,\mbox{GeV}/c^2. The limits on B(J/ψ→γa)\mathcal{B}(J/\psi\rightarrow\gamma a) range from 8.3×10−88.3\times10^{-8} to 1.8×10−61.8\times10^{-6} over the search region, and the constraints on the ALP-photon coupling are the most stringent to date for 0.165\leq m_a\leq1.468\,\mbox{GeV}/c^2.Comment: 10 pages, 5 figure

    Measurements of the electric and magnetic form factors of the neutron for time-like momentum transfer

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    We present the first measurements of the electric and magnetic form factors of the neutron in the time-like (positive q2q^2) region as function of four-momentum transfer. We explored the differential cross sections of the reaction e+e−→nˉne^+e^- \rightarrow \bar{n}n with data collected with the BESIII detector at the BEPCII accelerator, corresponding to an integrated luminosity of 354.6 pb−1^{-1} in total at twelve center-of-mass energies between s=2.0−2.95\sqrt{s} = 2.0 - 2.95 GeV. A relative uncertainty of 18% and 12% for the electric and magnetic form factors, respectively, is achieved at s=2.3935\sqrt{s} = 2.3935 GeV. Our results are comparable in accuracy to those from electron scattering in the comparable space-like (negative q2q^2) region of four-momentum transfer. The electromagnetic form factor ratio Rem≡∣GE∣/∣GM∣R_{\rm em}\equiv |G_E|/|G_M| is within the uncertainties close to unity. We compare our result on ∣GE∣|G_E| and ∣GM∣|G_M| to recent model predictions, and the measurements in the space-like region to test the analyticity of electromagnetic form factors.Comment: main paper: 9 pages, 6 figures, 3 tables; supplement: 9 pages, 28 table

    Search for an invisible muon philic scalar X0X_{0} or vector X1X_{1} via J/ψ→μ+μ−+invisibleJ/\psi\to\mu^+\mu^-+\rm{invisible} decay at BESIII

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    A light scalar X0X_{0} or vector X1X_{1} particles have been introduced as a possible explanation for the (g−2)μ(g-2)_{\mu} anomaly and dark matter phenomena. Using (8.998±0.039)×109(8.998\pm 0.039)\times10^9 \jpsi events collected by the BESIII detector, we search for a light muon philic scalar X0X_{0} or vector X1X_{1} in the processes J/ψ→μ+μ−X0,1J/\psi\to\mu^+\mu^- X_{0,1} with X0,1X_{0,1} invisible decays. No obvious signal is found, and the upper limits on the coupling g0,1′g_{0,1}' between the muon and the X0,1X_{0,1} particles are set to be between 1.1×10−31.1\times10^{-3} and 1.0×10−21.0\times10^{-2} for the X0,1X_{0,1} mass in the range of 1<M(X0,1)<10001<M(X_{0,1})<1000~MeV/c2/c^2 at 90%\% confidence level.Comment: 9 pages 7 figure

    Measurements of the branching fractions of the inclusive decays D0(D+)→π+π+π−X

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    Using eþe− annihilation data corresponding to an integrated luminosity of 2.93 fb−1 taken at a center-of mass energy of 3.773 GeV with the BESIII detector, we report the first measurements of the branching fractions of the inclusive decays D0 → πþπþπ−X and Dþ → πþπþπ−X, where pions from K0 S decays have been excluded from the πþπþπ− system and X denotes any possible particle combination. The branching fractions of D0ðDþÞ → πþπþπ−X are determined to be BðD0 → πþπþπ−XÞ¼ð17.60 0.11 0.22Þ% and BðDþ → πþπþπ−XÞ¼ð15.25 0.09 0.18Þ%, where the first uncertainties are statistical and the second systematic

    Female Sex Worker Social Networks and STI/HIV Prevention in South China

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    Reducing harm associated with selling and purchasing sex is an important public health priority in China, yet there are few examples of sustainable, successful programs to promote sexual health among female sex workers. The limited civil society and scope of nongovernmental organizations circumscribe the local capacity of female sex workers to collectively organize, advocate for their rights, and implement STI/HIV prevention programs. The purpose of this study was to examine social networks among low-income female sex workers in South China to determine their potential for sexual health promotion.Semi-structured interviews with 34 low-income female sex workers and 28 health outreach members were used to examine how social relationships affected condom use and negotiation, STI/HIV testing and health-seeking behaviors, and dealing with violent clients. These data suggested that sex worker's laoxiang (hometown social connections) were more powerful than relationships between women selling sex at the same venue in establishing the terms and risk of commercial sex. Female sex workers from the same hometown often migrated to the city with their laoxiang and these social connections fulfilled many of the functions of nongovernmental organizations, including collective mobilization, condom promotion, violence mitigation, and promotion of health-seeking behaviors. Outreach members observed that sex workers accompanied by their laoxiang were often more willing to accept STI/HIV testing and trust local sexual health services.Organizing STI/HIV prevention services around an explicitly defined laoxiang social network may provide a strong foundation for sex worker health programs. Further research on dyadic interpersonal relationships between female sex workers, group dynamics and norm establishment, and the social network characteristics are needed

    Updated measurements of the M1 transition ψ(3686)→γηc(2S)\psi(3686) \to \gamma \eta_{c}(2S) with ηc(2S)→KKˉπ\eta_{c}(2S) \to K \bar{K} \pi

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    Based on a data sample of (27.08±0.14)×108 ψ(3686)(27.08 \pm 0.14 ) \times 10^8~\psi(3686) events collected with the BESIII detector at the BEPCII collider, the M1 transition ψ(3686)→γηc(2S)\psi(3686) \to \gamma \eta_{c}(2S) with ηc(2S)→KKˉπ\eta_{c}(2S) \to K\bar{K}\pi is studied, where KKˉπK\bar{K}\pi is K+K−π0K^{+} K^{-} \pi^{0} or KS0K±π∓K_{S}^{0}K^{\pm}\pi^{\mp}. The mass and width of the ηc(2S)\eta_{c}(2S) are measured to be (3637.8±0.8(stat)±0.2(syst))(3637.8 \pm 0.8 (\rm {stat}) \pm 0.2 (\rm {syst})) MeV/c2c^{2} and (10.5±1.7(stat)±3.5(syst))(10.5 \pm 1.7 (\rm {stat}) \pm 3.5 (\rm {syst})) MeV, respectively. The product branching fraction B(ψ(3686)→γηc(2S))×B(ηc(2S)→KKˉπ)\mathcal{B}\left(\psi(3686) \rightarrow \gamma \eta_{c}(2 S)\right) \times \mathcal{B}(\eta_{c}(2 S) \rightarrow K \bar{K} \pi) is determined to be (0.97±0.06(stat)±0.09(syst))×10−5(0.97 \pm 0.06 (\rm {stat}) \pm 0.09 (\rm {syst})) \times 10^{-5}. Using BR(ηc(2S)→KKˉπ)=(1.86−0.49+0.68)%\mathcal{BR}(\eta_{c}(2S)\to K\bar{K}\pi)=(1.86^{+0.68}_{-0.49})\%, we obtain the branching fraction of the radiative transition to be BR(ψ(3686)→γηc(2S))=(5.2±0.3(stat)±0.5(syst)−1.4+1.9(extr))×10−4\mathcal{BR}(\psi(3686) \to \gamma \eta_{c}(2S)) = (5.2 \pm 0.3 (\rm {stat}) \pm 0.5 (\rm {syst}) ^{+1.9}_{-1.4} (extr)) \times 10^{-4}, where the third uncertainty is due to the quoted BR(ηc(2S)→KKˉπ)\mathcal{BR}(\eta_{c}(2S) \to K\bar{K}\pi)

    First Observation of a Three-Resonance Structure in e+e−→e^+e^-\rightarrow{non-open} Charm Hadrons

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    We report the measurement of the cross sections for e+e−e^+e^-→\rightarrow{nOCH} (nOCH stands for non-open charm hadrons) with improved precision at center-of-mass energies from 3.645 to 3.871 GeV. We observe for the first time a three-resonance structure in the energy-dependent lineshape of the cross sections, which are R(3760)\mathcal R(3760), R(3780)\mathcal R(3780) and R(3810)\mathcal R(3810) with significances of 9.4σ9.4\sigma, 15.7σ15.7\sigma, and 9.8σ9.8\sigma, respectively. The R(3810)\mathcal R(3810) is observed for the first time. We found two solutions in analysis of the cross sections. For solution I [solution II], we measure the mass, the total width and the product of electronic width and nOCH decay branching fraction to be (3805.8±1.1±2.7)(3805.8 \pm 1.1 \pm 2.7) [(3805.8±1.1±2.7)(3805.8 \pm 1.1 \pm 2.7)] MeV/c2c^2, (11.6±2.6±1.9)(11.6 \pm 2.6 \pm 1.9) [(11.5±2.5±1.8)(11.5 \pm 2.5 \pm 1.8)] MeV, and (10.8±3.2±2.3)(10.8\pm 3.2\pm 2.3) [(11.0±2.9±2.4)(11.0\pm 2.9\pm 2.4)] eV for the R(3810)\mathcal R(3810), respectively. In addition, we measure the branching fractions B(R(3760){\mathcal B}({\mathcal R}(3760)→\rightarrow{nOCH})=(24.5±13.4±27.4)%[(6.8±5.4±7.6)%])=(24.5 \pm 13.4 \pm 27.4)\% [(6.8 \pm 5.4 \pm 7.6)\%] for the first time, and B(R(3780){\mathcal B}(\mathcal R(3780)→\rightarrow{nOCH})=(11.6±5.8±7.8)%[(10.3±4.5±6.9)%])=(11.6 \pm 5.8 \pm 7.8)\% [(10.3 \pm 4.5 \pm 6.9)\%]. Moreover, we determine the open-charm (OC) branching fraction B(R{\mathcal B}({\mathcal R}(3760)→(3760)\rightarrow{OC})=(75.5±13.4±27.4)%[(93.2±5.4±7.6)%])=(75.5 \pm 13.4 \pm 27.4)\% [(93.2 \pm 5.4 \pm 7.6)\%], which supports the interpretation of R(3760)\mathcal R(3760) as an OC pair molecular state, but contained a simple four-quark state component. The first uncertainties are from fits to the cross sections, and the second are systematic

    Measurement of the e+e−→KS0KL0π0e^{+}e^{-} \to K_{S}^{0} K_{L}^{0} \pi^{0} cross sections from s=\sqrt{s}= 2.000 to 3.080 GeV

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    Based on e+e−e^{+}e^{-} collision data collected at center-of-mass energies from 2.000 to 3.080 GeV by the BESIII detector at the BEPCII collider, a partial wave analysis is performed for the process e+e−→KS0KL0π0e^{+}e^{-}\to K_{S}^{0} K_{L}^{0} \pi^{0}. The results allow the Born cross sections of the process e+e−→KS0KL0π0e^{+}e^{-}\to K_{S}^{0} K_{L}^{0} \pi^{0}, as well as its subprocesses e+e−→K∗(892)0Kˉe^{+}e^{-}\to K^{*}(892)^{0}\bar{K} and K2∗(1430)0KˉK^{*}_{2}(1430)^{0}\bar{K} to be measured. The Born cross sections for e+e−→KS0KL0π0e^{+}e^{-}\to K_{S}^{0} K_{L}^{0}\pi^{0} are consistent with previous measurements by BaBar and SND, but with substantially improved precision. The Born cross section lineshape of the process e+e−→K∗(892)0Kˉe^{+}e^{-}\to K^{*}(892)^{0}\bar{K} is consistent with a vector meson state around 2.2 GeV with a statistical significance of 3.2σ\sigma. A Breit-Wigner fit determines its mass as MY=(2164.1±9.6±3.1) MeV/c2M_Y=(2164.1\pm9.6\pm3.1)~{\rm{MeV}}/c^{2} and its width as ΓY=(32.4±21.1±1.5) MeV\Gamma_{Y}=(32.4\pm21.1\pm1.5)~\rm{MeV}, where the first uncertainties are statistical and the second ones are systematic, respectively
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