441 research outputs found

    Performance of Shannon-entropy compacted N-electron wave functions for configuration interaction methods

    Get PDF
    The coefficients of full configuration interaction wave functions (FCI) for N-electron systems expanded in N-electron Slater determinants depend on the orthonormal one-particle basis chosen although the total energy remains invariant. Some bases result in more compact wave functions, i.e. result in fewer determinants with significant expansion coefficients. In this work, the Shannon entropy, as a measure of information content, is evaluated for such wave functions to examine whether there is a relationship between the FCI Shannon entropy of a given basis and the performance of that basis in truncated CI approaches. The results obtained for a set of randomly picked bases are compared to those obtained using the traditional canonical molecular orbitals, natural orbitals, seniority minimising orbitals and a basis that derives from direct minimisation of the Shannon entropy. FCI calculations for selected atomic and molecular systems clearly reflect the influence of the chosen basis. However, it is found that there is no direct relationship between the entropy computed for each basis and truncated CI energies.Fil: Alcoba, Diego Ricardo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Torre, Alicia. Universidad de Buenos Aires; Argentina. Universidad de Buenos Aires; ArgentinaFil: Lain, Luis. Universidad del País Vasco; España. Universidad del País Vasco; EspañaFil: Massaccesi, Gustavo Ernesto. Universidad del País Vasco; España. Universidad del País Vasco; EspañaFil: Oña, Ofelia Beatriz. Universidad de Buenos Aires; Argentina. Universidad de Buenos Aires; ArgentinaFil: Ayers, P. W.. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Van Raemdonck, M.. Mcmaster University; Canadá. Mcmaster University; CanadáFil: Bultinck, P.. University of Ghent; Bélgica. University of Ghent; BélgicaFil: Van Neck, D.. University of Ghent; Bélgica. University of Ghent; Bélgic

    Lung transplantation from donation after brain death (DBD) donors on extra-corporeal support : A case series from the ESTS Lung Transplantation Working Group

    Get PDF
    In recent years, the use of extracorporeal membrane oxygenation (ECMO) support is increasing in critically ill patients. Lung recovery from donors on ECMO may counteract the donor pool shortage. However, this kind of donor remains a major challenge when assessing organ donor quality, namely the lung; also, in this setting pulmonary grafts could suffer from flow diversion. There is very little evidence in literature about outcomes in case of donors supported by ECMO. Aim of this study was to analyse data on procurement, transplantation and outcomes in lung recipients from donors after neurological determination of death (DBD) on ECMO

    A hybrid configuration interaction treatment based on seniority number and excitation schemes

    Get PDF
    We present a configuration interaction method in which the Hamiltonian of an N-electron system is projected on Slater determinants selected according to the seniority-number criterion along with the traditional excitation-based procedure. This proposed method is especially useful to describe systems which exhibit dynamic (weak) correlation at determined geometric arrangements (where the excitation-based procedure is more suitable) but show static (strong) correlation at other arrangements (where the seniority-number technique is preferred). The hybrid method amends the shortcomings of both individual determinant selection procedures, yielding correct shapes of potential energy curves with results closer to those provided by the full configuration interaction method.Fil: Alcoba, Diego Ricardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires; ArgentinaFil: Torre, Alicia. Universidad del Pais Vasco; EspañaFil: Lain, Luis. Universidad del Pais Vasco; EspañaFil: Oña, Ofelia Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; ArgentinaFil: Capuzzi, Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires; ArgentinaFil: Van Raemdonck, Mario. University of Ghent; BélgicaFil: Bultinck, Patrick. University of Ghent; BélgicaFil: Van Neck, Dimitri. University Of Ghent; Bélgic

    Quantitative analysis of airway obstruction in lymphangio-leio-myomatosis

    Get PDF
    Lymphangioleiomyomatosis (LAM) is a rare, cystic lung disease with progressive pulmonary function loss caused by progressively proliferating LAM cells. The degree of airway obstruction has not been well investigated within the pathogenesis of LAM. Using a combination of ex vivo computed tomography (CT), microCT and histology, the site and nature of airway obstruction in LAM explant lungs was compared with matched control lungs (n=5 each). The total number of airways per generation, total airway counts, terminal bronchioles number and surface density were compared in LAM versus control. Ex vivo CT analysis demonstrated a reduced number of airways from generation 7 on (p<0.0001) in LAM compared with control, whereas whole-lung microCT analysis confirmed the three- to four-fold reduction in the number of airways. Specimen microCT analysis further demonstrated a four-fold decrease in the number of terminal bronchioles (p=0.0079) and a decreased surface density (p=0.0079). Serial microCT and histology images directly showed the loss of functional airways by collapse of airways on the cysts and filling of the airway by exudate. LAM lungs show a three- to four-fold decrease in the number of (small) airways, caused by cystic destruction which is the likely culprit for the progressive loss of pulmonary function

    «La relation de limitation et d’exception dans le français d’aujourd’hui : excepté, sauf et hormis comme pivots d’une relation algébrique »

    Get PDF
    L’analyse des emplois prépositionnels et des emplois conjonctifs d’ “excepté”, de “sauf” et d’ “hormis” permet d’envisager les trois prépositions/conjonctions comme le pivot d’un binôme, comme la plaque tournante d’une structure bipolaire. Placées au milieu du binôme, ces prépositions sont forcées par leur sémantisme originaire dûment métaphorisé de jouer le rôle de marqueurs d’inconséquence systématique entre l’élément se trouvant à leur gauche et celui qui se trouve à leur droite. L’opposition qui surgit entre les deux éléments n’est donc pas une incompatibilité naturelle, intrinsèque, mais extrinsèque, induite. Dans la plupart des cas (emplois limitatifs), cette opposition prend la forme d’un rapport entre une « classe » et le « membre (soustrait) de la classe », ou bien entre un « tout » et une « partie » ; dans d’autres (emplois exceptifs), cette opposition se manifeste au contraire comme une attaque de front portée par un « tout » à un autre « tout ». De plus, l’inconséquence induite mise en place par la préposition/conjonction paraît, en principe, tout à fait insurmontable. Dans l’assertion « les écureuils vivent partout, sauf en Australie » (que l’on peut expliciter par « Les écureuils vivent partout, sauf [qu’ils ne vivent pas] en Australie »), la préposition semble en effet capable d’impliquer le prédicat principal avec signe inverti, et de bâtir sur une telle implication une sorte de sous énoncé qui, à la rigueur, est totalement inconséquent avec celui qui le précède (si « les écureuils ne vivent pas en Australie », le fait qu’ils « vivent partout » est faux). Néanmoins, l’analyse montre qu’alors que certaines de ces oppositions peuvent enfin être dépassées, d’autres ne le peuvent pas. C’est, respectivement, le cas des relations limitatives et des relations exceptives. La relation limitative, impliquant le rapport « tout » - « partie », permet de résoudre le conflit dans les termes d’une somme algébrique entre deux sous énoncés pourvus de différent poids informatif et de signe contraire. Les valeurs numériques des termes de la somme étant déséquilibrées, le résultat est toujours autre que zéro. La relation exceptive, au contraire, qui n’implique pas le rapport « tout » - « partie », n’est pas capable de résoudre le conflit entre deux sous énoncés pourvus du même poids informatif et en même temps de signe contraire : les valeurs numériques des termes de la somme étant symétriques et égales, le résultat sera toujours équivalent à zéro

    Survival After Lung Transplantation for Chronic Hypersensitivity Pneumonitis: Results From a Large International Cohort Study

    Get PDF
    Repeated exposure to antigens via inhalation is the primary cause of hypersensitivity pneumonitis, a form of interstitial pneumonia. The chronic form of hypersensitivity pneumonitis leads to progressive loss of respiratory function; lung transplantation is the only therapeutic option for chronically ill patients. The ESTS Lung Transplantation Working Group conducted a retrospective multicentred cohort study to increase the body of knowledge available on this rare indication for lung transplantation. Data were collected for every patient who underwent lung transplant for hypersensitivity pneumonitis in participating centres between December 1996 and October 2019. Primary outcome was overall survival; secondary outcome was freedom from chronic lung allograft dysfunction. A total of 114 patients were enrolled from 9 centres. Almost 90% of patients were diagnosed with hypersensitivity pneumonitis before transplantation, yet the antigen responsible for the infection was identified in only 25% of cases. Eighty per cent of the recipients received induction therapy. Survival at 1, 3, and 5 years was 85%, 75%, and 70%, respectively. 85% of the patients who survived 90 days after transplantation were free from chronic lung allograft dysfunction after 3 years. The given study presents a large cohort of HP patients who underwent lung transplants. Overall survival rate is higher in transplanted hypersensitivity pneumonitis patients than in those suffering from any other interstitial lung diseases. Hypersensitivity pneumonitis patients are good candidates for lung transplantation
    corecore