435 research outputs found

    An Introduction to Relativistic Theory as Implemented in GRASP

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    Computational atomic physics continues to play a crucial role in both increasing the understanding of fundamental physics (e.g., quantum electrodynamics and correlation) and producing atomic data for interpreting observations from large-scale research facilities ranging from fusion reactors to high-power laser systems, space-based telescopes and isotope separators. A number of different computational methods, each with their own strengths and weaknesses, is available to meet these tasks. Here, we review the relativistic multiconfiguration method as it applies to the General Relativistic Atomic Structure Package [grasp2018, C. Froese Fischer, G. Gaigalas, P. Jonsson, J. Bieron, Comput. Phys. Commun. (2018). DOI: 10.1016/j.cpc.2018.10.032]. To illustrate the capacity of the package, examples of calculations of relevance for nuclear physics and astrophysics are presented

    Epidemiology, Outcomes, and Complement Gene Variants in Secondary Thrombotic Microangiopathies.

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    The identification of complement defects as major drivers of primary atypical hemolytic uremic syndrome (HUS) has transformed the landscape of thrombotic microangiopathies (TMAs), leading to the development of targeted therapies and better patient outcomes. By contrast, little is known about the presentation, genetics, and outcomes of TMA associated with specific diseases or conditions, also referred to as secondary TMA. In this study, we assessed the relative incidence, clinical and genetic spectra, and long-term outcomes of secondary TMA versus other TMAs in consecutive patients hospitalized with a first episode of TMA from 2009 to 2019 at two European reference centers. During the study period, 336 patients were hospitalized with a first episode of TMA. Etiologies included atypical HUS in 49 patients (15%), thrombotic thrombocytopenic purpura (TTP) in 29 (9%), shigatoxin-associated HUS in 70 (21%), and secondary TMA in 188 (56%). The main causes of secondary TMA were hematopoietic stem-cell transplantation ( n =56, 30%), solid-organ transplantation ( n =44, 23%), and malignant hypertension ( n =25, 13%). Rare variants in complement genes were identified in 32 of 49 patients (65%) with atypical HUS and eight of 64 patients (13%) with secondary TMA; pathogenic or likely pathogenic variants were found in 24 of 49 (49%) and two of 64 (3%) of them, respectively ( P < 0.001). After a median follow-up of 1157 days, death or kidney failure occurred in 14 (29%), eight (28%), five (7%), and 121 (64%) patients with atypical HUS, TTP, shigatoxin-associated HUS, and secondary TMA, respectively. Unadjusted and adjusted Cox regressions showed that patients with secondary TMA had the highest risk of death or kidney failure (unadjusted hazard ratio [HR], 3.35; 95% confidence interval [CI], 1.85 to 6.07; P < 0.001; adjusted HR, 4.11; 95% CI, 2.00 to 8.46; P < 0.001; considering atypical HUS as reference). Secondary TMAs represent the main cause of TMA and are independently associated with a high risk of death and progression to kidney failure

    GRASP Manual for Users

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    grasp is a software package in Fortran 95, adapted to run in parallel under MPI, for research in atomic physics. The basic premise is that, given a wave function, any observed atomic property can be computed. Thus, the first step is always to determine a wave function. Different properties challenge the accuracy of the wave function in different ways. This software is distributed under the MIT Licence

    Performance Tests and Improvements on the <tt>rmcdhf</tt> and <tt>rci</tt> Programs of <sans-serif>GRASP</sans-serif>

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    The latest published version of GRASP (General-purpose Relativistic Atomic Structure Package), i.e., GRASP2018, retains a few suboptimal subroutines/algorithms, which reflect the limited memory and file storage of computers available in the 1980s. Here we show how the efficiency of the relativistic self-consistent-field (SCF) procedure of the multiconfiguration-Dirac–Hartree–Fock (MCDHF) method and the relativistic configuration-interaction (RCI) calculations can be improved significantly. Compared with the original GRASP codes, the present modified version reduces the CPU times by factors of a few tens or more. The MPI performances for all the original and modified codes are carefully analyzed. Except for diagonalization, all computational processes show good MPI scaling

    Evaluation Des Connaissances, Attitudes Et Pratiques Des Mères Sur Les Soins A Domicile Chez Les Enfants De 0 A 5 Ans Avec Diarrhée Dans Le Quartier Du Congo. Ville De Gemena /Sud-Ubangi

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    La présente étude vise à évaluer les connaissances, attitudes et pratiques des mères face aux soins à donner à domicile chez les enfants de 0 à 5 ans avec diarrhée. Une enquête analytique et transversale a été menée auprès de 200 mères du quartier du Congo dans la ville de Gemena. Un questionnaire a servi à recueillir les données. La prévalence de la diarrhée chez les enfants de 0 à 5 ans était de 28,6%. Le SRO a été reconnu par 65,5% des mères, néanmoins 96,7% savent le préparer et se lavent les mains avant la préparation

    Evaluation Des Connaissances, Des Femmes Enceintes Sur La CPN Recentrées Dans l’Aire De Sante Bokuda Ville De Gemena /Sud-Ubangi

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    de temps à temps, le problème lié à la grossesse constitue une préoccupation  pour l’humanité en vue  de réaliser sa destinée sociale. Pour évaluer le niveau de connaissance des femmes enceintes, nous avons utilisé la méthode d’enquête avec la technique d’interview soutenu par un questionnaire préétablit. Il ressort de cette étude que les mères ont une connaissance sur la CPN recentrée mais n’y fréquentent pas. La Négligence des femmes suite à leurs diverses activités est à la base. Nous encourageons les femmes enceintes à consulter le service prénatal tôt pour garantir la santé du couple « mère-nouveau-né 

    Performance Tests and Improvements on the rmcdhf and rci Programs of GRASP

    No full text
    The latest published version of GRASP (General-purpose Relativistic Atomic Structure Package), i.e., GRASP2018, retains a few suboptimal subroutines/algorithms, which reflect the limited memory and file storage of computers available in the 1980s. Here we show how the efficiency of the relativistic self-consistent-field (SCF) procedure of the multiconfiguration-Dirac-Hartree-Fock (MCDHF) method and the relativistic configuration-interaction (RCI) calculations can be improved significantly. Compared with the original GRASP codes, the present modified version reduces the CPU times by factors of a few tens or more. The MPI performances for all the original and modified codes are carefully analyzed. Except for diagonalization, all computational processes show good MPI scaling

    Benchmarking calculations of wavelengths and transition rates with spectroscopic accuracy for W XLVIII through W LVI tungsten ions

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    Atomic properties of n=3 levels for W47+-W55+ ions (Z=74) are systematically calculated using two different and independent methods, namely, the second-order many-body perturbation theory and the multiconfiguration Dirac-Hartree-Fock method combined with the relativistic configuration interaction approach. Wavelengths and transition rates for electric-and magnetic-dipole transitions involving the n=3 levels of W47+-W55+ are calculated. In addition, we discuss in detail the importance of the valence and core-valence electron correlations, the Breit interaction, the higher-order frequency-dependent retardation correction, and the leading quantum electrodynamical corrections for transition wavelengths. Spectroscopic accuracy is achieved for the present calculated wavelengths, and most of them agree with experimental values within 0.05%. Our calculated wavelengths, combined with collisional radiative model simulations, are used to identify the yet unidentified 25 observed lines in the extremely complex spectrum between 27Ă… and 34Ă… measured by Lennartsson etal. [Phys. Rev. A 87, 062505 (2013)10.1103/PhysRevA.87.062505]. We provide additional data for 472 strong electric-dipole transitions in the wavelength range of 17-50 Ă…, and 185 strong magnetic-dipole transitions between 36Ă… and 4384Ă…, with a line intensity greater than 1photon/s. These can provide benchmark data for future experiments and theoretical calculations

    An Introduction to Relativistic Theory as Implemented in GRASP

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    Computational atomic physics continues to play a crucial role in both increasing the understanding of fundamental physics (e.g., quantum electrodynamics and correlation) and producing atomic data for interpreting observations from large-scale research facilities ranging from fusion reactors to high-power laser systems, space-based telescopes and isotope separators. A number of different computational methods, each with their own strengths and weaknesses, is available to meet these tasks. Here, we review the relativistic multiconfiguration method as it applies to the General Relativistic Atomic Structure Package [grasp2018, C. Froese Fischer, G. Gaigalas, P. Jönsson, J. Bieroń, Comput. Phys. Commun. (2018). DOI: 10.1016/j.cpc.2018.10.032]. To illustrate the capacity of the package, examples of calculations of relevance for nuclear physics and astrophysics are presented
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