162 research outputs found

    Combination antiretroviral therapy and the risk of myocardial infarction

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    Illegal births and legal abortions – the case of China

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    BACKGROUND: China has a national policy regulating the number of children that a woman is allowed to have. The central concept at the individual level application is "illegal pregnancy". The purpose of this article is to describe and problematicize the concept of illegal pregnancy and its use in practice. METHODS: Original texts and previous published and unpublished reports and statistics were used. RESULTS: By 1979 the Chinese population policy was clearly a policy of controlling population growth. For a pregnancy to be legal, it has to be defined as such according to the family-level eligibility rules, and in some places it has to be within the local quota. Enforcement of the policy has been pursued via the State Family Planning (FP) Commission and the Communist Party (CP), both of which have a functioning vertical structure down to the lowest administrative units. There are various incentives and disincentives for families to follow the policy. An extensive system has been created to keep the contraceptive use and pregnancy status of all married women at reproductive age under constant surveillance. In the early 1990s FP and CP officials were made personally responsible for meeting population targets. Since 1979, abortion has been available on request, and the ratio of legal abortions to birth increased in the 1980s and declined in the 1990s. Similar to what happens in other Asian countries with low fertility rates and higher esteem for boys, both national- and local-level data show that an unnaturally greater number of boys than girls are registered as having been born. CONCLUSION: Defining a pregnancy as "illegal" and carrying out the surveillance of individual women are phenomena unique in China, but this does not apply to other features of the policy. The moral judgment concerning the policy depends on the basic question of whether reproduction should be considered as an individual or social decision

    Observation of Two New Excited Ξb0 States Decaying to Λb0 K-π+

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    Two narrow resonant states are observed in the Λb0K-π+ mass spectrum using a data sample of proton-proton collisions at a center-of-mass energy of 13 TeV, collected by the LHCb experiment and corresponding to an integrated luminosity of 6 fb-1. The minimal quark content of the Λb0K-π+ system indicates that these are excited Ξb0 baryons. The masses of the Ξb(6327)0 and Ξb(6333)0 states are m[Ξb(6327)0]=6327.28-0.21+0.23±0.12±0.24 and m[Ξb(6333)0]=6332.69-0.18+0.17±0.03±0.22 MeV, respectively, with a mass splitting of Δm=5.41-0.27+0.26±0.12 MeV, where the uncertainties are statistical, systematic, and due to the Λb0 mass measurement. The measured natural widths of these states are consistent with zero, with upper limits of Γ[Ξb(6327)0]<2.20(2.56) and Γ[Ξb(6333)0]<1.60(1.92) MeV at a 90% (95%) credibility level. The significance of the two-peak hypothesis is larger than nine (five) Gaussian standard deviations compared to the no-peak (one-peak) hypothesis. The masses, widths, and resonant structure of the new states are in good agreement with the expectations for a doublet of 1D Ξb0 resonances

    Measurement of the CKM angle γ\gamma using B0DK0B^0 \rightarrow D K^{*0} with DKS0π+πD \rightarrow K^0_S \pi^+ \pi^- decays

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    A model-dependent amplitude analysis of the decay B0D(KS0π+π)K0B^0\rightarrow D(K^0_S\pi^+\pi^-) K^{*0} is performed using proton-proton collision data corresponding to an integrated luminosity of 3.0fb1^{-1}, recorded at s=7\sqrt{s}=7 and 8TeV8 TeV by the LHCb experiment. The CP violation observables x±x_{\pm} and y±y_{\pm}, sensitive to the CKM angle γ\gamma, are measured to be \begin{eqnarray*} x_- &=& -0.15 \pm 0.14 \pm 0.03 \pm 0.01, y_- &=& 0.25 \pm 0.15 \pm 0.06 \pm 0.01, x_+ &=& 0.05 \pm 0.24 \pm 0.04 \pm 0.01, y_+ &=& -0.65^{+0.24}_{-0.23} \pm 0.08 \pm 0.01, \end{eqnarray*} where the first uncertainties are statistical, the second systematic and the third arise from the uncertainty on the DKS0π+πD\rightarrow K^0_S \pi^+\pi^- amplitude model. These are the most precise measurements of these observables. They correspond to γ=(8022+21)\gamma=(80^{+21}_{-22})^{\circ} and rB0=0.39±0.13r_{B^0}=0.39\pm0.13, where rB0r_{B^0} is the magnitude of the ratio of the suppressed and favoured B0DK+πB^0\rightarrow D K^+ \pi^- decay amplitudes, in a KπK\pi mass region of ±50MeV\pm50 MeV around the K(892)0K^*(892)^0 mass and for an absolute value of the cosine of the K0K^{*0} decay angle larger than 0.40.4.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2016-007.htm

    Search for dark photons produced in 13 TeV pppp collisions

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    Searches are performed for both promptlike and long-lived dark photons, A 0 , produced in proton-proton collisions at a center-of-mass energy of 13 TeV, using A 0 → μ þ μ − decays and a data sample corresponding to an integrated luminosity of 1 . 6 fb − 1 collected with the LHCb detector. The promptlike A 0 search covers the mass range from near the dimuon threshold up to 70 GeV, while the long-lived A 0 search is restricted to the low-mass region 214 <m ð A 0 Þ < 350 MeV. No evidence for a signal is found, and 90% confidence level exclusion limits are placed on the γ – A 0 kinetic-mixing strength. The constraints placed on promptlike dark photons are the most stringent to date for the mass range 10 . 6 <m ð A 0 Þ < 70 GeV, and are comparable to the best existing limits for m ð A 0 Þ < 0 . 5 GeV. The search for long-lived dark photons is the first to achieve sensitivity using a displaced-vertex signature

    Measurement of antiproton production from antihyperon decays in p He collisions at √sNN = 110 GeV

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    The interpretation of cosmic antiproton flux measurements from space-borne experiments is currently limited by the knowledge of the antiproton production cross-section in collisions between primary cosmic rays and the interstellar medium. Using collisions of protons with an energy of 6.5TeV incident on helium nuclei at rest in the proximity of the interaction region of the LHCb experiment, the ratio of antiprotons originating from antihyperon decays to prompt production is measured for antiproton momenta between 12 and 110GeV. The dominant antihyperon contribution, namely Λ¯→p¯π+ decays from promptly produced Λ¯ particles, is also exclusively measured. The results complement the measurement of prompt antiproton production obtained from the same data sample. At the energy scale of this measurement, the antihyperon contributions to antiproton production are observed to be significantly larger than predictions of commonly used hadronic production models

    Direct CP violation in charmless three-body decays of B± mesons

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    Measurements of C P asymmetries in charmless three-body decays of B ± mesons are reported using proton-proton collision data collected by the LHCb detector, corresponding to an integrated luminosity of 5.9     fb − 1 . The previously observed C P asymmetry in B ± → π ± K + K − decays is confirmed, and C P asymmetries are observed with a significance of more than five standard deviations in the B ± → π ± π + π − and B ± → K ± K + K − decays, while the C P asymmetry of B ± → K ± π + π − decays is confirmed to be compatible with zero. The distributions of these asymmetries are also studied as a function of the three-body phase space and suggest contributions from rescattering and resonance interference processes. An indication of the presence of the decays B ± → π ± χ c 0 ( 1 P ) in both B ± → π ± π + π − and B ± → π ± K + K − decays is observed, as is C P violation involving these amplitudes
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