0000000000271987
AUTHOR
J. Pereira
showing 17 related works from this author
Global age-sex-specific fertility, mortality, healthy life expectancy (HALE), and population estimates in 204 countries and territories, 1950–2019: a…
2020
Background Accurate and up-to-date assessment of demographic metrics is crucial for understanding a wide range of social, economic, and public health issues that affect populations worldwide. The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 produced updated and comprehensive demographic assessments of the key indicators of fertility, mortality, migration, and population for 204 countries and territories and selected subnational locations from 1950 to 2019. Methods 8078 country-years of vital registration and sample registration data, 938 surveys, 349 censuses, and 238 other sources were identified and used to estimate age-specific fertility. Spatiotemporal Gaussian…
Measurement of key resonance states for the P30(p,γ)S31 reaction rate, and the production of intermediate-mass elements in nova explosions
2017
We report the first experimental constraints on spectroscopic factors and strengths of key resonances in the P30(p,γ)S31 reaction critical for determining the production of intermediate-mass elements up to Ca in nova ejecta. The P30(d,n)S31 reaction was studied in inverse kinematics using the GRETINA γ -ray array to measure the angle-integrated cross-sections of states above the proton threshold. In general, negative-parity states are found to be most strongly produced but the absolute values of spectroscopic factors are typically an order of magnitude lower than predicted by the shell-model calculations employing WBP Hamiltonian for the negative-parity states. The results clearly indicat…
New experimental efforts along the rp-process path
2007
The level structure just above the proton threshold of the nucleus 30S has been studied using the neutron removal process on fast radioactive beams at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University. In this work we provide a description of the experimental setup. The present status of the analysis is also discussed.
β-decay measurements ofA≃ 70 − 110 r-process nuclei at the National Superconducting Cyclotron Laboratory
2011
The present paper reports on several r-process motivated β-decay experiments undertaken at the National Superconducting Cyclotron Laboratory. β-decay half-lives and β-delayed neutron-emission probabilities were measured for nuclei around the r-process A = 70–80 and A = 90 – 110 mass regions. The data are discussed on the basis of quasi-random phase approximation calculations. The emphasis is made on the impact of these data upon calculations of r-process abundances.
β-decay studies of r-process nuclei at NSCL
2008
Abstract Observed neutron-capture elemental abundances in metal-poor stars, along with ongoing analysis of the extremely metal-poor Eu-enriched sub-class provide new guidance for astrophysical models aimed at finding the r-process sites. The present paper emphasizes the importance of nuclear physics parameters entering in these models, particularly β -decay properties of neutron-rich nuclei. In this context, several r-process motivated β -decay experiments performed at the National Superconducting Cyclotron Laboratory (NSCL) are presented, including a summary of results and impact on model calculations.
β-decay half-lives andβ-delayed neutron emission probabilities of nuclei in the regionA≲110, relevant for the r process
2009
Measurements of $\ensuremath{\beta}$-decay properties of $A\ensuremath{\lesssim}110$ r-process nuclei have been completed at the National Superconducting Cyclotron Laboratory at Michigan State University. $\ensuremath{\beta}$-decay half-lives for $^{105}\mathrm{Y}$, $^{106,107}\mathrm{Zr}$, and $^{111}\mathrm{Mo}$, along with $\ensuremath{\beta}$-delayed neutron emission probabilities of $^{104}\mathrm{Y}$, $^{109,110}\mathrm{Mo}$ and upper limits for $^{105}\mathrm{Y}$, $^{103\ensuremath{-}107}\mathrm{Zr}$, and $^{108,111}\mathrm{Mo}$ have been measured for the first time. Studies on the basis of the quasi-random-phase approximation are used to analyze the ground-state deformation of these…
Improving the nuclear physics input along the rp-process path
2007
The level structure of 30 S was studied at the NSCL by using neutron removal reactions with a radioactive 31 S beam. The γ -decay from excited states in 30 S was measured in a Ge-detector array. The results discussed for this work will reduce the uncertainties in the determination of the astrophysical 29 P(p, γ ) 30 S reaction rate under rp -process conditions.
Nucleosynthesis of proton-rich nuclei. Experimental results on the rp-process
2009
Experience NSCL; International audience; We report in this study the nuclear properties of proton-rich isotopes located along the rp-process path. The experiments have recently been performed at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University. The level properties above the proton separation energy of the nuclei 30S, 36K and 37Ca were measured with precision of < 10 keV. This will allow a reduction in the determination of the astrophysical (p, ) reaction rate under rp-process conditions.
The neutron long counter NERO for studies of neutron emission in the r-process
2010
Abstract The neutron long counter NERO was built at the National Superconducting Cyclotron Laboratory (NSCL), Michigan State University, for measuring β -delayed neutron-emission probabilities. The detector was designed to work in conjunction with a β -delay implantation station, so that β decays and β -delayed neutrons emitted from implanted nuclei can be measured simultaneously. The high efficiency of about 40%, for the range of energies of interest, along with the small background, are crucial for measuring β -delayed neutron emission branchings for neutron-rich r-process nuclei produced as low intensity fragmentation beams in in-flight separator facilities.
Measurements of Spallation Residues Using Inverse Kinematics at GSI
2002
The production cross sections and the kinematical properties of primary residual nuclei have been studied in reactions 197Au + p, 208Pb + p, d, 238U + p, d, and 238U + 208Pb at energies around 1 A GeV. The measured kinematical properties of the residues were also used to disentangle the relevant reaction mechanisms, spallation-evaporation and spallation-fission. The fragment separator FRS at GSI, Darmstadt, was used to separate and identify the reaction products. The measured quantities are important for the design and planning of future radioactive-beam facilities and accelerator-driven systems.
Single-particle shell strengths near the doubly magic nucleus 56Ni and the 56Ni(p,γ)57Cu reaction rate in explosive astrophysical burning
2019
Angle-integrated cross-section measurements of the $^{56}$Ni(d,n) and (d,p) stripping reactions have been performed to determine the single-particle strengths of low-lying excited states in the mirror nuclei pair $^{57}$Cu-$^{57}$Ni situated adjacent to the doubly magic nucleus $^{56}$Ni. The reactions were studied in inverse kinematics utilizing a beam of radioactive $^{56}$Ni ions in conjunction with the GRETINA $\gamma$-array. Spectroscopic factors are compared with new shell-model calculations using a full $pf$ model space with the GPFX1A Hamiltonian for the isospin-conserving strong interaction plus Coulomb and charge-dependent Hamiltonians. These results were used to set new constrain…
Determining therp-Process Flow throughNi56: Resonances inCu57(p,γ)Zn58Identified with GRETINA
2014
An approach is presented to experimentally constrain previously unreachable (p, γ) reaction rates on nuclei far from stability in the astrophysical rp process. Energies of all critical resonances in the (57)Cu(p,γ)(58)Zn reaction are deduced by populating states in (58)Zn with a (d, n) reaction in inverse kinematics at 75 MeV/u, and detecting γ-ray-recoil coincidences with the state-of-the-art γ-ray tracking array GRETINA and the S800 spectrograph at the National Superconducting Cyclotron Laboratory. The results reduce the uncertainty in the (57)Cu(p,γ) reaction rate by several orders of magnitude. The effective lifetime of (56)Ni, an important waiting point in the rp process in x-ray burst…
Low-lying level structure of Cu56 and its implications for the rp process
2017
The low-lying energy levels of proton-rich Cu56 have been extracted using in-beam γ-ray spectroscopy with the state-of-the-art γ-ray tracking array GRETINA in conjunction with the S800 spectrograph at the National Superconducting Cyclotron Laboratory at Michigan State University. Excited states in Cu56 serve as resonances in the Ni55(p,γ)Cu56 reaction, which is a part of the rp process in type-I x-ray bursts. To resolve existing ambiguities in the reaction Q value, a more localized isobaric multiplet mass equation (IMME) fit is used, resulting in Q=639±82 keV. We derive the first experimentally constrained thermonuclear reaction rate for Ni55(p,γ)Cu56. We find that, with this new rate, the …
Single-particle shell strengths near the doubly magic nucleus Ni and the Ni( , ) Cu reaction rate in explosive astrophysical burning
2019
Angle-integrated cross-section measurements of the $^{56}$Ni(d,n) and (d,p) stripping reactions have been performed to determine the single-particle strengths of low-lying excited states in the mirror nuclei pair $^{57}$Cu−$^{57}$Ni situated adjacent to the doubly magic nucleus $^{56}$Ni. The reactions were studied in inverse kinematics utilizing a beam of radioactive $^{56}$Ni ions in conjunction with the GRETINA γ-array. Spectroscopic factors are compared with new shell-model calculations using a full pf model space with the GPFX1A Hamiltonian for the isospin-conserving strong interaction plus Coulomb and charge-dependent Hamiltonians. These results were used to set new constraints on the…
Global, regional, and national progress towards Sustainable Development Goal 3.2 for neonatal and child health: all-cause and cause-specific mortalit…
2021
Background: Sustainable Development Goal 3.2 has targeted elimination of preventable child mortality, reduction of neonatal death to less than 12 per 1000 livebirths, and reduction of death of children younger than 5 years to less than 25 per 1000 livebirths, for each country by 2030. To understand current rates, recent trends, and potential trajectories of child mortality for the next decade, we present the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 findings for all-cause mortality and cause-specific mortality in children younger than 5 years of age, with multiple scenarios for child mortality in 2030 that include the consideration of potential effects of COVID-…
Five insights from the Global Burden of Disease Study 2019
2020
The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 provides a rules-based synthesis of the available evidence on levels and trends in health outcomes, a diverse set of risk factors, and health system responses. GBD 2019 covered 204 countries and territories, as well as first administrative level disaggregations for 22 countries, from 1990 to 2019. Because GBD is highly standardised and comprehensive, spanning both fatal and non-fatal outcomes, and uses a mutually exclusive and collectively exhaustive list of hierarchical disease and injury causes, the study provides a powerful basis for detailed and broad insights on global health trends and emerging challenges. GBD …
R-process experimental campaign at the National Superconducting Cyclotron Laboratory
2006
A JINA/VISTARS r-process campaign was completed at the A1900 Fragment Separator of the National Superconducting Cyclotron Laboratory in the fall of 2005. The purpose of the campaign was the measurement of the beta-decay half-lives and beta-delayed neutron-emission probabilities of different unknown neutron-rich nuclei participating in the r-process. Details of this campaign will be presented.