251 research outputs found

    Polarization entangled photon-pair source based on a type-II PPLN waveguide emitting at a telecom wavelength

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    We report the realization of a fiber coupled polarization entangled photon-pair source at 1310 nm based on a birefringent titanium in-diffused waveguide integrated on periodically poled lithium niobate. By taking advantage of a dedicated and high-performance setup, we characterized the quantum properties of the pairs by measuring two-photon interference in both Hong-Ou-Mandel and standard Bell inequality configurations. We obtained, for the two sets of measurements, interference net visibilities reaching nearly 100%, which represent important and competitive results compared to similar waveguide-based configurations already reported. These results prove the relevance of our approach as an enabling technology for long-distance quantum communication.Comment: 13 pages, 4 figures, to appear in New Journal of Physic

    First identification of excited states in the Tz_z = 1/2 nucleus 93^{93}Pd

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    The first experimental information about excited states in the N = Z + 1 nucleus 93Pd is presented. The experiment was performed using a 205 MeV 58Ni beam from the Vivitron accelerator at IReS, Strasbourg, impinging on a bismuth-backed 40Ca target. Gamma-rays, neutrons and charged particles emitted in the reactions were detected using the Ge detector array Euroball, the Neutron Wall liquid-scintillator array and the Euclides Si charged-particle detector system. The experimental level scheme is compared with the results of new shell model calculations which predict a coupling scheme with aligned neutron-proton pairs to greatly influence the level structure of NZN\approx Z nuclei at low excitation energies

    Economic analysis of antenatal screening for human T-cell lymphotropic virus type 1 in Brazil: an open access cost-utility model

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    BACKGROUND: Human T-cell lymphotropic virus type 1 (HTLV-1) is a retrovirus that causes severe diseases, such as aggressive cancer or progressive neurological disease. HTLV-1 affects mainly people in areas with low human development index and can be transmitted from mother to child, primarily through breastfeeding. Refraining from breastfeeding is an effective intervention to reduce the risk of infection in infants. However, HTLV-1 antenatal screening is not offered globally. According to WHO, the scarcity of cost-effectiveness studies is considered one of the major barriers to the implementation of policies to prevent HTLV-1 infection. Therefore, this study aimed to assess the cost-effectiveness of antenatal screening and postnatal interventions to prevent HTLV-1 mother-to-child transmission in Brazil and to develop an open-access, editable, mathematical model that can be used by other countries and regions to assess different scenarios. METHODS: In this cost-utility analysis, we constructed a decision tree and a Markov model to assess the cost-effectiveness of HTLV-1 antenatal screening and postnatal interventions (ie, avoidance of breastfeeding, by suppression of lactation with cabergoline, and provision of formula feed) to reduce transmission. For our model, we used data from Brazil and we took the perspective of the public health-care system to estimate costs. FINDINGS: The implementation of both screening and interventions would result in the prevention of 1039 infections in infants every year in Brazil with an incremental cost-effectiveness ratio (ICER) of US11415perqualityadjustedlifeyear(QALY).8811 415 per quality-adjusted life-year (QALY). 88% of all probabilistic sensitivity analysis simulations had ICER values lower than the Brazilian cost-effectiveness threshold (18 107·74 per QALY). HTLV-1 prevalence in pregnant women, the risk of HTLV-1 transmission when breastfeeding lasts for 6 months or more, and the cost of screening tests were the variables with the largest effect on ICER. INTERPRETATION: HTLV-1 antenatal screening is cost-effective in Brazil. An open-access model was developed, and this tool could be used to assess the cost-effectiveness of such policy globally, favouring the implementation of interventions to prevent HTLV-1 mother-to-child transmission worldwide. FUNDING: None. TRANSLATIONS: For the Portuguese and Spanish translations of the abstract see Supplementary Materials section

    Spectroscopy of 28^{28}Na: shell evolution toward the drip line

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    Excited states in 28^{28}Na have been studied using the β\beta-decay of implanted 28^{28}Ne ions at GANIL/LISE as well as the in-beam γ\gamma-ray spectroscopy at the NSCL/S800 facility. New states of positive (Jπ^{\pi}=3,4+^+) and negative (Jπ^{\pi}=1-5^-) parity are proposed. The former arise from the coupling between 0d_5/2\_{5/2} protons and a 0d_3/2\_{3/2} neutron, while the latter are due to couplings with 1p_3/2\_{3/2} or 0f_7/2\_{7/2} neutrons. While the relative energies between the Jπ^{\pi}=1-4+^+ states are well reproduced with the USDA interaction in the N=17 isotones, a progressive shift in the ground state binding energy (by about 500 keV) is observed between 26^{26}F and 30^{30}Al. This points to a possible change in the proton-neutron 0d_5/2\_{5/2}-0d_3/2\_{3/2} effective interaction when moving from stability to the drip line. The presence of Jπ^{\pi}=1-4^- negative parity states around 1.5 MeV as well as of a candidate for a Jπ^{\pi}=5^- state around 2.5 MeV give further support to the collapse of the N=20 gap and to the inversion between the 0f_7/2\_{7/2} and 1p_3/2\_{3/2} levels below Z=12. These features are discussed in the framework of Shell Model and EDF calculations, leading to predicted negative parity states in the low energy spectra of the 26^{26}F and 25^{25}O nuclei.Comment: Exp\'erience GANIL/LISE et NSCL/S80

    Core-coupled states and split proton-neutron quasi-particle multiplets in 122-126Ag

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    Neutron-rich silver isotopes were populated in the fragmentation of a 136Xe beam and the relativistic fission of 238U. The fragments were mass analyzed with the GSI Fragment separator and subsequently implanted into a passive stopper. Isomeric transitions were detected by 105 HPGe detectors. Eight isomeric states were observed in 122-126Ag nuclei. The level schemes of 122,123,125Ag were revised and extended with isomeric transitions being observed for the first time. The excited states in the odd-mass silver isotopes are interpreted as core-coupled states. The isomeric states in the even-mass silver isotopes are discussed in the framework of the proton-neutron split multiplets. The results of shell-model calculations, performed for the most neutron-rich silver nuclei are compared to the experimental data

    Basic Subsistence Needs and Overall Health Among Human Immunodeficiency Virus-infected Homeless and Unstably Housed Women

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    Some gender differences in the progression of human immunodeficiency virus (HIV) infection have been attributed to delayed treatment among women and the social context of poverty. Recent economic difficulties have led to multiple service cuts, highlighting the need to identify factors with the most influence on health in order to prioritize scarce resources. The aim of this study was to empirically rank factors that longitudinally impact the health status of HIV-infected homeless and unstably housed women. Study participants were recruited between 2002 and 2008 from community-based venues in San Francisco, California, and followed over time; marginal structural models and targeted variable importance were used to rank factors by their influence. In adjusted analysis, the factor with the strongest effect on overall mental health was unmet subsistence needs (i.e., food, hygiene, and shelter needs), followed by poor adherence to antiretroviral therapy, not having a close friend, and the use of crack cocaine. Factors with the strongest effects on physical health and gynecologic symptoms followed similar patterns. Within this population, an inability to meet basic subsistence needs has at least as much of an effect on overall health as adherence to antiretroviral therapy, suggesting that advances in HIV medicine will not fully benefit indigent women until their subsistence needs are met

    Identification of high- K rotation in Ba130 : Testing the consistency of electromagnetic observables

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    The band built on the Kπ = 8−, T1/2 = 9.4 ms isomer of 130Ba has been identified, filling the gap in the systematics of the dipole bands built on the 8− isomers in the N = 74 isotones from 128Xe to 138Gd. The use of the GALILEO array in conjunction with its ancillaries EUCLIDES and Neutron Wall, helped to firmly place the newly identified transitions on top of the long-lived isomer. The extracted gK and gR gyromagnetic factors are in agreement with the 7/2+[404] ⊗ 9/2−[514] two-neutron Nilsson configuration. Particle-rotor model calculations give an understanding of the limited degree of K mixing. The experimental information on the Kπ = 8− isomer of 130Ba is now the most complete among the K isomers of the N = 74 isotones
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