3,141 research outputs found

    Knowledge and beliefs on vaccines among a sample of Italian pregnant women: results from the NAVIDAD study

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    BACKGROUND: Vaccine hesitancy is an emerging phenomenon in European countries and leads to decreasing trends in infant vaccine coverage. The aim of this study was to analyze the level of confidence and correct awareness about immunizations, which are crucial for the success of vaccination programmes. METHODS: As part of the NAVIDAD multicentre study, we examined vaccination confidence and complacency among a sample of 1820 pregnant women from 14 Italian cities. The questionnaire assessed the interviewee's knowledge, beliefs and misconceptions, as well as their socioeconomic status, information sources about vaccines and confidence in the Italian National Healthcare Service. RESULTS: Only 9% of women completely believed to the efficacy, necessity and safety of vaccinations. Almost 20% of them had misconceptions on most of the themes. There was a significant difference in the level of knowledge considering educational level: women with a high educational level have less probability of obtaining a low knowledge score (odds ratio (OR) 0.43 [95% confidence interval (CI) 0.34-0.54]). The level of knowledge was also influenced by the sources of information: women who received information from their general practitioner (GP) and from institutional websites had a significantly lower chance of having misconceptions (OR 0.74 [95% CI 0.58-0.96]; OR 0.59 [95% CI 0.46-0.74]). Finally, the results underlined the influence of trust in healthcare professional information on the likelihood of having misconceptions (OR 0.49 [95% CI 0.27-0.89]). CONCLUSIONS: The data suggest the efficacy of GPs and institutional websites as a source of information to contrast misconceptions and underline the importance of confidence in the healthcare system to increase complacency and confidence in vaccines

    Quantum state preparation and macroscopic entanglement in gravitational-wave detectors

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    Long-baseline laser-interferometer gravitational-wave detectors are operating at a factor of 10 (in amplitude) above the standard quantum limit (SQL) within a broad frequency band. Such a low classical noise budget has already allowed the creation of a controlled 2.7 kg macroscopic oscillator with an effective eigenfrequency of 150 Hz and an occupation number of 200. This result, along with the prospect for further improvements, heralds the new possibility of experimentally probing macroscopic quantum mechanics (MQM) - quantum mechanical behavior of objects in the realm of everyday experience - using gravitational-wave detectors. In this paper, we provide the mathematical foundation for the first step of a MQM experiment: the preparation of a macroscopic test mass into a nearly minimum-Heisenberg-limited Gaussian quantum state, which is possible if the interferometer's classical noise beats the SQL in a broad frequency band. Our formalism, based on Wiener filtering, allows a straightforward conversion from the classical noise budget of a laser interferometer, in terms of noise spectra, into the strategy for quantum state preparation, and the quality of the prepared state. Using this formalism, we consider how Gaussian entanglement can be built among two macroscopic test masses, and the performance of the planned Advanced LIGO interferometers in quantum-state preparation

    Searching for a Stochastic Background of Gravitational Waves with LIGO

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    The Laser Interferometer Gravitational-wave Observatory (LIGO) has performed the fourth science run, S4, with significantly improved interferometer sensitivities with respect to previous runs. Using data acquired during this science run, we place a limit on the amplitude of a stochastic background of gravitational waves. For a frequency independent spectrum, the new limit is ΩGW<6.5×105\Omega_{\rm GW} < 6.5 \times 10^{-5}. This is currently the most sensitive result in the frequency range 51-150 Hz, with a factor of 13 improvement over the previous LIGO result. We discuss complementarity of the new result with other constraints on a stochastic background of gravitational waves, and we investigate implications of the new result for different models of this background.Comment: 37 pages, 16 figure

    Constraints on the χ_(c1) versus χ_(c2) polarizations in proton-proton collisions at √s = 8 TeV

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    The polarizations of promptly produced χ_(c1) and χ_(c2) mesons are studied using data collected by the CMS experiment at the LHC, in proton-proton collisions at √s=8  TeV. The χ_c states are reconstructed via their radiative decays χ_c → J/ψγ, with the photons being measured through conversions to e⁺e⁻, which allows the two states to be well resolved. The polarizations are measured in the helicity frame, through the analysis of the χ_(c2) to χ_(c1) yield ratio as a function of the polar or azimuthal angle of the positive muon emitted in the J/ψ → μ⁺μ⁻ decay, in three bins of J/ψ transverse momentum. While no differences are seen between the two states in terms of azimuthal decay angle distributions, they are observed to have significantly different polar anisotropies. The measurement favors a scenario where at least one of the two states is strongly polarized along the helicity quantization axis, in agreement with nonrelativistic quantum chromodynamics predictions. This is the first measurement of significantly polarized quarkonia produced at high transverse momentum
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