15 research outputs found

    A mathematical and computational review of Hartree-Fock SCF methods in Quantum Chemistry

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    We present here a review of the fundamental topics of Hartree-Fock theory in Quantum Chemistry. From the molecular Hamiltonian, using and discussing the Born-Oppenheimer approximation, we arrive to the Hartree and Hartree-Fock equations for the electronic problem. Special emphasis is placed in the most relevant mathematical aspects of the theoretical derivation of the final equations, as well as in the results regarding the existence and uniqueness of their solutions. All Hartree-Fock versions with different spin restrictions are systematically extracted from the general case, thus providing a unifying framework. Then, the discretization of the one-electron orbitals space is reviewed and the Roothaan-Hall formalism introduced. This leads to a exposition of the basic underlying concepts related to the construction and selection of Gaussian basis sets, focusing in algorithmic efficiency issues. Finally, we close the review with a section in which the most relevant modern developments (specially those related to the design of linear-scaling methods) are commented and linked to the issues discussed. The whole work is intentionally introductory and rather self-contained, so that it may be useful for non experts that aim to use quantum chemical methods in interdisciplinary applications. Moreover, much material that is found scattered in the literature has been put together here to facilitate comprehension and to serve as a handy reference.Comment: 64 pages, 3 figures, tMPH2e.cls style file, doublesp, mathbbol and subeqn package

    Sistemas de protección y detección de contagios en los pediatras de atención primaria en la epidemia por COVID-19

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    Introducción: durante la pandemia de COVID-19, el uso de equipos y dispositivos de protección por parte de los profesionales es fundamental para evitar la transmisión de la infección en el colectivo de sanitarios. Material y métodos: el Grupo Laboral-Profesional de la Asociación Española de Pediatría de Atención Primaria (AEPap) ha realizado una encuesta a los vocales autonómicos de la AEPap para conocer la disponibilidad que han tenido los pediatras de Atención Primaria (PAP) de sistemas de protección frente a la enfermedad, y las pruebas diagnósticas realizadas para el diagnóstico de los contagios de los PAP. Resultados: en marzo de 2020, solo en el 32% de las comunidades autónomas (CC. AA.), los pediatras tenían sistemas de protección adecuados. En abril ascendió al 70%. En todas las CC. AA. se han registrado casos de PAP enfermos, aunque es difícil cuantificar el número de afectados. De las que tenemos datos, sumando el número de pediatras enfermos conocido, más test de reacción en cadena de la polimerasa (PCR) positivo, los que han estado en aislamiento y los ingresados, la cifra asciende al 7,65% de la cifra total de PAP. Los test rápidos serológicos o PCR o ambos se han realizado en seis comunidades los últimos días de abril y en otras seis los primeros días de mayo. Entre las CC. AA. de las que hay información, Aragón es la única comunidad en la que no se ha realizado test. Se ha correlacionado la disponibilidad de los sistemas de protección y el gasto sanitario. Conclusiones: los sistemas de protección han sido insuficientes. Las CC. AA. con mayor gasto sanitario han contado más precozmente con sistemas de protección adecuados. Han resultado infectados PAP en todas las comunidades autónomas, especialmente en Madrid, Castilla y León y Comunidad Valenciana. La detección de profesionales afectos por la infección ha sido tardía

    International nosocomial infection control consortium (INICC) report, data summary of 36 countries, for 2004-2009

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    The results of a surveillance study conducted by the International Nosocomial Infection Control Consortium (INICC) from January 2004 through December 2009 in 422 intensive care units (ICUs) of 36 countries in Latin America, Asia, Africa, and Europe are reported. During the 6-year study period, using Centers for Disease Control and Prevention (CDC) National Healthcare Safety Network (NHSN; formerly the National Nosocomial Infection Surveillance system [NNIS]) definitions for device-associated health care-associated infections, we gathered prospective data from 313,008 patients hospitalized in the consortium's ICUs for an aggregate of 2,194,897 ICU bed-days. Despite the fact that the use of devices in the developing countries' ICUs was remarkably similar to that reported in US ICUs in the CDC's NHSN, rates of device-associated nosocomial infection were significantly higher in the ICUs of the INICC hospitals; the pooled rate of central line-associated bloodstream infection in the INICC ICUs of 6.8 per 1,000 central line-days was more than 3-fold higher than the 2.0 per 1,000 central line-days reported in comparable US ICUs. The overall rate of ventilator-associated pneumonia also was far higher (15.8 vs 3.3 per 1,000 ventilator-days), as was the rate of catheter-associated urinary tract infection (6.3 vs. 3.3 per 1,000 catheter-days). Notably, the frequencies of resistance of Pseudomonas aeruginosa isolates to imipenem (47.2% vs 23.0%), Klebsiella pneumoniae isolates to ceftazidime (76.3% vs 27.1%), Escherichia coli isolates to ceftazidime (66.7% vs 8.1%), Staphylococcus aureus isolates to methicillin (84.4% vs 56.8%), were also higher in the consortium's ICUs, and the crude unadjusted excess mortalities of device-related infections ranged from 7.3% (for catheter-associated urinary tract infection) to 15.2% (for ventilator-associated pneumonia). Copyright © 2012 by the Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved

    Caracterización de hematomas de edad conocida en bovinos de carne a través de innovadoras técnicas forenses. [abstract].

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    El objetivo del presente trabajo fue caracterizar hematomas de edades conocidas, a través de diferentes técnicas. Se utilizaron 60 novillos Hereford, provocando un hematoma por animal, a través de un dispositivo mecánico especialmente diseñado, en la región de la grupa y afectando músculo, previa aplicación de anestesia local

    Quantitative proteomic analysis of host—pathogen interactions: a study of Acinetobacter baumannii responses to host airways

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    BACKGROUND: Acinetobacter baumannii is a major health problem. The most common infection caused by A. baumannii is hospital acquired pneumonia, and the associated mortality rate is approximately 50 %. Neither in vivo nor ex vivo expression profiling has been performed at the proteomic or transcriptomic level for pneumonia caused by A. baumannii. In this study, we characterized the proteome of A. baumannii under conditions that simulate those found in the airways, to gain some insight into how A. baumannii adapts to the host and to improve knowledge about the pathogenesis and virulence of this bacterium. A clinical strain of A. baumannii was grown under different conditions: in the presence of bronchoalveolar lavage fluid from infected rats, of RAW 264.7 cells to simulate conditions in the respiratory tract and in control conditions. We used iTRAQ labelling and LC-MALDI-TOF/TOF to investigate how A. baumannii responds on exposure to macrophages/BALF. RESULTS: 179 proteins showed differential expression. In both models, proteins involved in the following processes were over-expressed: (i) pathogenesis and virulence (OmpA, YjjK); (ii) cell wall/membrane/envelope biogenesis (MurC); (iii) energy production and conversion (acetyl-CoA hydrolase); and (iv) translation (50S ribosomal protein L9). Proteins involved in the following were under-expressed: (i) lipid metabolism (short-chain dehydrogenase); (ii) amino acid metabolism and transport (aspartate aminotransferase); (iii) unknown function (DNA-binding protein); and (iv) inorganic ion transport and metabolism (hydroperoxidase). CONCLUSIONS: We observed alterations in cell wall synthesis and identified 2 upregulated virulence-associated proteins with >15 peptides/protein in both ex vivo models (OmpA and YjjK), suggesting that these proteins are fundamental for pathogenesis and virulence in the airways. This study is the first comprehensive overview of the ex vivo proteome of A. baumannii and is an important step towards identification of diagnostic biomarkers, novel drug targets and potential vaccine candidates in the fight against pneumonia caused by A. baumannii. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12864-015-1608-z) contains supplementary material, which is available to authorized users

    Needles in a haystack: Extremely rare invasive fungal infections reported in FungiScopeⓇ—Global Registry for Emerging Fungal Infections

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    Asymmetric architecture is non-random and repeatable in a bird’s nests

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