510 research outputs found

    Electronic structure of crystalline binary and ternary Cd-Te-O compounds

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    The electronic structure of crystalline CdTe, CdO, α\alpha-TeO2_2, CdTeO3_3 and Cd3_3TeO6_6 is studied by means of first principles calculations. The band structure, total and partial density of states, and charge densities are presented. For α\alpha-TeO2_2 and CdTeO3_3, Density Functional Theory within the Local Density Approximation (LDA) correctly describes the insulating character of these compounds. In the first four compounds, LDA underestimates the optical bandgap by roughly 1 eV. Based on this trend, we predict an optical bandgap of 1.7 eV for Cd3_3TeO6_6. This material shows an isolated conduction band with a low effective mass, thus explaining its semiconducting character observed recently. In all these oxides, the top valence bands are formed mainly from the O 2p electrons. On the other hand, the binding energy of the Cd 4d band, relative to the valence band maximum, in the ternary compounds is smaller than in CdTe and CdO.Comment: 13 pages, 15 figures, 2 tables. Accepted in Phys Rev

    Costs associated with delivering HPV vaccination in the context of the first year demonstration programme in southern Mozambique.

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    BACKGROUND: In Mozambique cervical cancer is a public health threat, due to its high incidence and limited access to early diagnosis of precancerous lesions. International organisations are supporting the introduction of human papillomavirus (HPV) vaccines in low- and middle-income countries. Some of these countries recently conducted demonstration programmes, which included evaluation of acceptability, coverage, and practicality of implementation and of integration in existing programmes. Information on costs of delivering the vaccine is needed to overcome the challenges of reaching vaccine potential recipients in rural and remote areas. METHODS: We estimated the financial and economic costs of delivering HPV vaccination to ten-year-old girls at schools for the first vaccination cycle of the demonstration programme in the Manhiça district (southern Mozambique), delivered throughout 2014. We also estimated costs of an alternative scenario with a reduced number of doses and personnel, which was analogous to the second vaccination cycle delivered throughout 2015. Cost estimates followed a micro-costing approach and included interviews with key informants at different administrative levels through the administration of standard questionnaires developed by the World Health Organisation. RESULTS: Considering only data from the first vaccination cycle (2014), which consisted in the administration of three doses, the average economic cost was US17.59 perdoseandUS17.59 per dose and US52.29 per fully-immunised girl (FIG). Financial cost per dose (US6.07)and perFIG(US6.07) and per FIG (US17.95) were substantially lower. The economic cost was US15.53 perdoseandUS15.53 per dose and US31.14 per FIG when estimating an alternative cost scenario with reduced number of doses and personnel. CONCLUSIONS: The average economic cost per dose was lower than the ones recently reported for low- and middle-income countries. However, our estimation of the financial cost per FIG was higher than the ones observed elsewhere (ranging from US2.49inIndiatoUS2.49 in India to US20.36 in Vietnam) due to the high percentage of out-of-school girls which, reduced vaccine coverage and, therefore, reduced the denominator. Due to budget constraints, if Mozambique is to implement nation-wide HPV vaccination targeted to ten-year-old girls at schools, a reduction in personnel costs should be operated either by restricting the outreach vaccinator team or the number of supervision visits

    Navigating challenges:STI policies for sustainable and inclusive development in Latin America

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    This paper explores the challenges and opportunities for Latin America in adopting sustainable development strategies, with a particular focus on Science, Technology and Innovattion (STI) policies. It gathers the insights of a group of distinguished scholars on STI policies, social inclusion and sustainability from the region who participated in the panel organized by the UNESCO Chair during the LALICS* conference held in Asuncion, Paraguay, on 19-21 June 2023.It addresses the challenges that hinder Latin America’s inclusive, sustainable and innovative development process from different perspectives. Highlighted challenges include strong inequality, high informality levels, and low R&D expenditure, heterogeneous productive structure posing obstacles to innovation and their governance. Scholars highlight the role of STI policies and the engagement of academia, government, and business in reducing inequality and promoting social protection, and discuss the technological capabilities needed to address climate change and digitalisation in the region

    Navigating challenges:STI policies for sustainable and inclusive development in Latin America

    Get PDF
    This paper explores the challenges and opportunities for Latin America in adopting sustainable development strategies, with a particular focus on Science, Technology and Innovattion (STI) policies. It gathers the insights of a group of distinguished scholars on STI policies, social inclusion and sustainability from the region who participated in the panel organized by the UNESCO Chair during the LALICS* conference held in Asuncion, Paraguay, on 19-21 June 2023.It addresses the challenges that hinder Latin America’s inclusive, sustainable and innovative development process from different perspectives. Highlighted challenges include strong inequality, high informality levels, and low R&D expenditure, heterogeneous productive structure posing obstacles to innovation and their governance. Scholars highlight the role of STI policies and the engagement of academia, government, and business in reducing inequality and promoting social protection, and discuss the technological capabilities needed to address climate change and digitalisation in the region

    Chiral three-nucleon forces and bound excited states in neutron-rich oxygen isotopes

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    We study the spectra of neutron-rich oxygen isotopes based on chiral two- and three-nucleon interactions. First, we benchmark our many-body approach by comparing ground-state energies to coupled-cluster results for the same two-nucleon interaction, with overall good agreement. We then calculate bound excited states in 21,22,23O, focusing on the role of three-nucleon forces, in the standard sd shell and an extended sdf7/2p3/2 valence space. Chiral three-nucleon forces provide important one- and two-body contributions between valence neutrons. We find that both these contributions and an extended valence space are necessary to reproduce key signatures of novel shell evolution, such as the N = 14 magic number and the low-lying states in 21O and 23O, which are too compressed with two-nucleon interactions only. For the extended space calculations, this presents first work based on nuclear forces without adjustments. Future work is needed and open questions are discussed.Comment: 6 pages, 4 figures, published versio

    Neutrinoless double beta decay in seesaw models

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    We study the general phenomenology of neutrinoless double beta decay in seesaw models. In particular, we focus on the dependence of the neutrinoless double beta decay rate on the mass of the extra states introduced to account for the Majorana masses of light neutrinos. For this purpose, we compute the nuclear matrix elements as functions of the mass of the mediating fermions and estimate the associated uncertainties. We then discuss what can be inferred on the seesaw model parameters in the different mass regimes and clarify how the contribution of the light neutrinos should always be taken into account when deriving bounds on the extra parameters. Conversely, the extra states can also have a significant impact, cancelling the Standard Model neutrino contribution for masses lighter than the nuclear scale and leading to vanishing neutrinoless double beta decay amplitudes even if neutrinos are Majorana particles. We also discuss how seesaw models could reconcile large rates of neutrinoless double beta decay with more stringent cosmological bounds on neutrino masses.Comment: 34 pages, 5 eps figures and 1 axodraw figure. Final version published in JHEP. NME results available in Appendi

    Critical Role of Electrical Resistivity in Magnetoionics

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    The utility of electrical resistivity as an indicator of magnetoionic performance in stoichiometrically and structurally similar thin-film systems is demonstrated. A series of highly nanocrystalline cobalt nitride (Co-N) thin films (85 nm thick) with a broad range of electrical properties exhibit markedly different magnetoionic behaviors. Semiconducting, near stoichiometric CoN films show the best performance, better than their metallic and insulating counterparts. Resistivity reflects the interplay between atomic bonding, carrier localization, and structural defects, and in turn determines the strength and distribution of applied electric fields inside the actuated films. This fact, generally overlooked, reveals that resistivity can be used to quickly evaluate the potential of a system to exhibit optimal magnetoionic effects, while also opening interesting challenges.Financial support by the European Research Council (SPIN-PORICS 2014-Consolidator Grant, Agreement No. 648454, and the MAGIC-SWITCH 2019-Proof of Concept Grant, Agreement No. 875018), the Spanish Government (MAT2017-86357-C3-1-R and PID2020- 116844RB-C21), the Generalitat de Catalunya (2017- SGR-292 and 2018-LLAV-00032) and the European Regional Development Fund (MAT2017-86357-C3-1-R and 2018-LLAV-00032) is acknowledged. This work was partially supported by the Impulse-und Net-working fund of the Helmholtz Association (FKZ VH-VI-442 Memriox), and the Helmholtz Energy Materials Characterization Platform (03ET7015). The PALS measurements were carried out at ELBE at the Helmholtz-Zentrum DresdenRossendorf e. V., a member of the Helmholtz Association. L.A. thanks MINECO for a Ramón y Cajal Contract (RYC-2013-12640). J.S. thanks the Spanish Fábrica Nacional de Moneda y Timbre for fruitful discussions. E.M. acknowledges support as a Serra Húnter Fellow. We acknowledge service from MiNa Laboratory at IMNCSIC

    The Spatial Extent of (U)LIRGs in the mid-Infrared I: The Continuum Emission

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    We present an analysis of the extended mid-infrared (MIR) emission of the Great Observatories All-Sky LIRG Survey (GOALS) sample based on 5-15um low resolution spectra obtained with the IRS on Spitzer. We calculate the fraction of extended emission as a function of wavelength for the galaxies in the sample, FEE_lambda. We can identify 3 general types of FEE_lambda: one where it is constant, one where features due to emission lines and PAHs appear more extended than the continuum, and a third which is characteristic of sources with deep silicate absorption at 9.7um. More than 30% of the galaxies have a median FEE_lambda larger than 0.5 implying that at least half of their MIR emission is extended. Luminous Infrared Galaxies (LIRGs) display a wide range of FEE in their warm dust continuum (0<=FEE_13.2um<=0.85). The large values of FEE_13.2um that we find in many LIRGs suggest that their extended MIR continuum emission originates in scales up to 10kpc. The mean size of the LIRG cores at 13.2um is 2.6kpc. However, once the LIR of the systems reaches the threshold of ~10^11.8Lsun, all sources become clearly more compact, with FEE_13.2um<=0.2, and their cores are unresolved. Our estimated upper limit for the core size of ULIRGs is less than 1.5kpc. The analysis indicates that the compactness of systems with LIR>~10^11.25Lsun strongly increases in those classified as mergers in their final stage of interaction. The FEE_13.2um is also related to the contribution of an active galactic nucleus (AGN) to the MIR. Galaxies which are more AGN-dominated are less extended, independently of their LIR. We finally find that the extent of the MIR continuum emission is correlated with the far-IR IRAS log(f_60um/f_100um) color. This enables us to place a lower limit to the area in a galaxy from where the cold dust emission may originate, a prediction which can be tested soon with the Herschel Space Telescope.Comment: 18 pages, 8 figures, accepted for publication in Ap
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