Modeling the Mg I from the NUV to MIR. I. The solar case

Context. Semi-empirical models of the solar atmosphere are used to study the radiative environment of any planet in our Solar System. There is a need for reliable atomic data for neutral atoms and ions in the atmosphere to obtain improved calculated spectra. Atomic parameters are crucial to computing the correct population of elements through the whole stellar atmosphere. Although there is very good agreement between the observed and calculated spectra for the Sun, there is still a mismatch in several spectral ranges due to the lack of atomic data and the inaccuracies thereof, particularly for neutrals such as Mga» I. Aims. To represent many spectral lines of Mga» I from the near-ultraviolet to the mid-infrared correctly, it is necessary to add and update the atomic data involved in the atomic processes that drive their formation. Methods. The improvements made to the Mga» I atomic model are as follows: i) 127 strong lines, including their broadening data, were added. ii) To obtain these new lines, we increased the number of energy levels from 26 to 85. iii) Photoionization cross-section parameters were added and updated. iv) Effective collision strength (I' ij ) parameters were updated for the first 25 levels using the existing data from the convergent close-coupling calculations. One of the most significant changes in our model is given by the new I' ij parameters for transitions involving levels between 26 and 54, which were computed with a multiconfiguration Breit-Pauli distorted-wave (DW) method. For transitions involving superlevels, we calculated the I' ij parameters with the usual semi-empirical formulas. Results. More than 100 transitions were added to our calculations, increasing our capability of reproducing important features observed in the solar spectra. We found a remarkable improvement in matching the solar spectra for wavelengths higher than 30 000 Å when our new DW I' ij data were used in the model.Fil: Peralta, Juan Ignacio. Universidad Nacional de Tres de Febrero; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Vieytes, Mariela Cristina. Universidad Nacional de Tres de Febrero; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Mendez, Marta Patricia Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Mitnik, Dario Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentin

Experimental and theoretical L-shell ionization cross sections of heavy atoms by impact of Si ions

We present a theoretical and experimental study of the subshell resolved L-shell ionization of relativistic targets such as 73Ta, 78Pt,90Th, and 92U. The measurements of x-ray production cross sections by (84?140 MeV) Si+q ions (q = 8; 12), were held at the Inter-University Accelerator Centre of New Delhi. Multiple-hole fluorescence and Coster-Kronig yields were used to obtain the Li(i = 1?3)ionization cross sections from the measured x-ray production cross sections of Lℓ, Lα, and Lβ, Lη, and Lγ lines. The experimental results are compared with ab initio theoretical calculations by means of the shell-wise local plasma approximation (SLPA). This model uses the quantum dielectric formalism to obtain the total ionization cross sections from an initial ground state. The wave functions and binding energies of the different targets were obtained by solving the fully-relativistic Dirac equation using the HULLAC code package. These calculations are based on first-order perturbation theory with a central field, including Breit interaction and quantum electrodynamics corrections. The present SLPA ionization cross sections of the L-shell are found to be independent of the charge state of the Si ions. The experimental observations display also quite similar character if the correct mean projectile charge state inside the target is used for including the multiple ionization effect during ion-solid collisions. A general good agreement between the experimental measurements and full theoretical calculations supports the reliability of present results. The comparison also includes the well-known ECPSSR and ECUSAR semi empirical approximations. We noted that the ECUSAR results agree well with the SLPA, while the ECPSSR cross sections are rather low.Fil: Oswal, M.. Dev Samaj College; India. Panjab University; IndiaFil: Kumar, Sunil. Panjab University; India. Degree college; IndiaFil: Singh, Udai. Jagiellonian University; PoloniaFil: Singh, G.. Panjab University; IndiaFil: Singh, K.P.. Panjab University; IndiaFil: Mehta, D.. Panjab University; IndiaFil: Mendez, Marta Patricia Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Mitnik, Dario Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Montanari, Claudia Carmen. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Mitra, D.. Kalyani University; IndiaFil: Nandi, T.. Inter-University Accelerator Centre; Indi

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

Correction to: Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

The original version of this article unfortunately contained a mistake

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

Optimization of atomic and molecular targets in collisional processes

El objetivo de esta Tesis consiste en desarrollar novedosas metodologías que permitan obtener datos precisos de estructura de blancos atómicos y moleculares para su posterior empleo en el cálculo de procesos inelásticos. A lo largo de este trabajo,se estu dian átomos livianos y pesados, así como moléculas simples y complejas, incluyendo las nucleobases. Entre las metodologías formuladas se incluye un método de inversión para la obtención de potenciales efectivos, que se utilizan para calcular la ionización de átomos y moléculas simples por el impacto de protones y fotones. Se presenta un modelo estequiométrico para describir sistemas moleculares complejos, que permite calcular la ionización de moléculas con interés biológico debido al impacto de iones de carga múltiple. Basados en la inferencia Bayesiana, ampliamente usada en el aprendizaje automatizado, se diseña una meto dología para ajustar observables en colisiones atómicas. Para el cálculo de frenado de iones en átomos pesados, se prescribe un método relativista perturbativo junto a la optimización de las conguraciones electrónicas. En todos los casos, las técnicas pro- puestas permiten describir en forma precisa la estructura electrónica de los blancos, mejorando signicativamente la calidad y eficiencia de los cálculos colisionales.This thesis aims to develop novel methodologies that allow obtaining precise atomic and molecular structure data of targets for their subsequent use in calculating inelastic processes. Light and heavy atoms, as well as simple and complex molecules, are studied throughout this work. The methodologies formulated include an inversion method to obtain eective potentials, which are used to calculate the ionization of atoms and simple molecules by the impact of protons and photons. A stoichiometric model is presented to describe complex molecular systems, which allows calculating the ionization of molecules with biological interest due to the impact of multi-charged ions. Based on the Bayesian inference, a technique widely used in machine learning, a procedure is designed to optimize observables in atomic collisions. For calculating energy loss in heavy atoms, a perturbative relativistic method is prescribed, along with the optimization of the electron congurations. In all cases, the proposed techniques allow a precise description of the electronic structure of the targets, improving the quality and eciency of collisional calculations signicantly.Fil: Mendez, Marta Patricia Alejandra. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

Ionization of biological molecules by multicharged ions using the stoichiometric model

In the present work, we investigate the ionization of molecules of biological interest by the impact of multicharged ions in the intermediate to high energy range. We performed full non-perturbative distorted-wave calculations (CDW) for thirty-six collisional systems composed by six atomic targets: H, C, N, O, F, and S-which are the constituents of most of the DNA and biological molecules- A nd six charged projectiles (antiprotons, H, He, B, C, and O). On account of the radiation damage caused by secondary electrons, we inspect the energy and angular distributions of the emitted electrons from the atomic targets. We examine seventeen molecules: DNA and RNA bases, DNA backbone, pyrimidines, tetrahydrofuran (THF), and CnHn compounds. We show that the simple stoichiometric model (SSM), which approximates the molecular ionization cross sections as a linear combination of the atomic ones, gives reasonably good results for complex molecules. We also inspect the extensively used Toburen scaling of the total ionization cross sections of molecules with the number of weakly bound electrons. Based on the atomic CDW results, we propose new active electron numbers, which leads to a better universal scaling for all the targets and ions studied here in the intermediate to the high energy region. The new scaling describes well the available experimental data for proton impact, including small molecules. We perform full molecular calculations for five nucleobases and test a modified stoichiometric formula based on the Mulliken charge of the composite atoms. The difference introduced by the new stoichiometric formula is less than 3%, which indicates the reliability of the SSM to deal with this type of molecules. The results of the extensive ion-target examination included in the present study allow us to assert that the SSM and the CDW-based scaling will be useful tools in this area.Fil: Mendez, Marta Patricia Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Montanari, Claudia Carmen. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Miraglia, Jorge Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentin

Local Effective Hartree–Fock Potentials Obtained by the Depurated Inversion Method

In this work we show the results of a numerical experiment performed on the Hartree–Fock (HF) wave functions in order to understand the relationship between the positions of the orbital nodes and the inflection points (zeros of their second derivative). This analysis is equivalent to investigating the existence of a physical one-electron local potential representing the interactions between the electrons. We found that with successive improvements in the quality of the numerical methods, the nodes and the inflection points systematically become closer. When the nodes coincide exactly with the inflection points, the existence of an effective local potential would be proven. However, this requirement cannot be fulfilled unless an explicit constraint (missing in the standard method) is incorporated into the HF procedure. The depurated inversion method (DIM) was devised to obtain detailed nl-orbital potentials for atoms and molecules. The method is based on the inversion of Kohn–Sham-type equations, followed by a further careful optimization which eliminates singularities and also ensures the fulfillment of the appropriate boundary conditions. The orbitals resulting from these potentials have their internal inflection points located exactly at the nodes. In this way, the DIM can be employed to obtain effective potentials that accurately reproduce the HF orbitals.Fil: Mendez, Marta Patricia Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Mitnik, Dario Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Miraglia, Jorge Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentin

Depurated inversion method for orbital-specific exchange potentials

This work presents exchange potentials for specific orbitals calculated by inverting Hartree–Fock wavefunctions. This was achieved by using a Depurated Inversion Method. The basic idea of the method relies on the substitution of Hartree–Fock orbitals and eigenvalues into the Kohn–Sham equation. Through inversion, the corresponding effective potentials were obtained. Further treatment of the inverted potential should be carried on. The depuration is a careful optimization which eliminates the poles and also ensures the fullfilment of the appropriate boundary conditions. The procedure developed here is not restricted to the ground state or to a nodeless orbital and is applicable to all kinds of atoms. As an example, exchange potentials for noble gases and term-dependent orbitals of the lower configuration of Nitrogen are calculated. The method allows to reproduce the input energies and wavefunctions with a remarkable degree of accuracy.Fil: Mendez, Marta Patricia Alejandra. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Mitnik, Dario Marcelo. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Miraglia, Jorge Esteban. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentin

Scaling rules for the ionization of biological molecules by highly charged ions

We investigate scaling rules for the ionization cross sections of multicharged ions on molecules of biological interest. The cross sections are obtained using a methodology presented by Mendez et al (2020 J. Phys. B: At. Mol. Opt. Phys. 53 055201), which considers distorted-wave calculations for atomic targets combined with a molecular stoichiometric model. We examine ions with nuclear charges Z from +1 to +8 impacting on five nucleobases -adenine, cytosine, guanine, thymine, uracil-, tetrahydrofuran, pyrimidine, and water. We investigate scaling rules of the ionization cross section with the ion charge and the number of active electrons per molecule. Combining these two features, we define a scaling law for any ion and molecular target, which is valid in the intermediate to high energy range, i.e. 0.2-5 MeV amu-1 for oxygen impact. Thus, the forty ion-molecule systems analyzed here can be merged into a single band. We confirm the generality of our independent scaling law with several collisional systems.Fil: Mendez, Marta Patricia Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Montanari, Claudia Carmen. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Miraglia, Jorge Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentin