29 research outputs found

    Cosmic Covariance and the Low Quadrupole Anisotropy of the Wilkinson Microwave Anisotropy Probe (WMAP) Data

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    The quadrupole power of cosmic microwave background (CMB) temperature anisotropies seen in the WMAP data is puzzlingly low. In this paper we demonstrate that Minimum Variance Optimization (MVO), a technique used by many authors (including the WMAP science team) to separate the CMB from contaminating foregrounds, has the effect of forcing the extracted CMB map to have zero statistical correlation with the foreground emission. Over an ensemble of universes the true CMB and foreground are indeed expected to be uncorrelated, but any particular sky pattern (such as the one we happen to observe) will generate non-zero measured correlations simply by chance. We call this effect "cosmic covariance" and it is a possible source of bias in the CMB maps cleaned using the MVO technique. We show that the presence of cosmic covariance is expected to artificially suppress the variance of the Internal Linear Combination (ILC) map obtained via MVO. It also propagates into the multipole expansion of the ILC map, generating a quadrupole deficit with more than 90% confidence. Since we do not know the CMB and the foregrounds a priori, there is therefore an unknown contribution to the uncertainty in the measured quadrupole power, over and above the usual cosmic variance contribution. Using the MVO on a series of Monte Carlo simulations that assume Gaussian CMB fluctuations, we estimate that the real quadrupole power of the CMB lies in the range [305.16,400.40] microKelvin^2 (at the 1-sigma level).Comment: 3 figures, submitted to Ap

    Frailty in primary care: a review of its conceptualization and implications for practice

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    Frail, older patients pose a challenge to the primary care physician who may often feel overwhelmed by their complex presentation and tenuous health status. At the same time, family physicians are ideally suited to incorporate the concept of frailty into their practice. They have the propensity and skill set that lends itself to patient-centred care, taking into account the individual subtleties of the patient's health within their social context. Tools to identify frailty in the primary care setting are still in the preliminary stages of development. Even so, some practical measures can be taken to recognize frailty in clinical practice and begin to address how its recognition may impact clinical care. This review seeks to address how frailty is recognised and managed, especially in the realm of primary care

    Recurrent Disseminated Skin Lesions Due to Metarrhizium anisopliae in an Adult Patient with Acute Myelogenous Leukemia

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    Metarrhizium anisopliae is a common insect pathogen that rarely causes infection in animals and humans. We report the first case of a disseminated skin infection in an immunocompromised adult patient. To date, only five cases of the disease in humans have been reported. There is no standard treatment for this infection

    Combined approach to the identification of clinically infrequent non-tuberculous mycobacteria in Argentina

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    SETTING: Over 150 potentially pathogenic non-tuberculous mycobacteria (NTM) species have been described, posing an onerous challenge for clinical laboratory diagnosis. OBJECTIVE: To evaluate different approaches for the identification of 40 clinically relevant NTM isolates whose species were not reliably identified using our routine diagnostic workflow comprising phenotypic tests and hsp65 polymerase chain reaction restriction analysis. DESIGN: We used 1) sequencing analysis of four conserved gene targets: 16S rRNA, rpoB, hsp65 and sodA; 2) two commercial reverse hybridisation assays; and 3) protein analysis using matrix-assisted laser desorption/ionisation time of flight mass spectrometry (MALDI-TOF MS). RESULTS: Combined, but not individual, sequence analysis allowed reliable species identification for 30/ 40 (75%) isolates, including species previously unknown to be circulating in Argentina. Commercial kits outperformed our routine identification in only 5/35 isolates, and misclassified many more. MALDI-TOF MS accurately identified species in 22/36 (61%) isolates and did not misidentify any. CONCLUSIONS: Commercial kits did not resolve the problem of species of NTM isolates that elude identification. Combined DNA sequence analysis was the approach of choice. MALDI-TOF MS shows promise as a powerful, rapid and accessible tool for the rapid identification of clinically relevant NTM in the diagnostic laboratory, and its accuracy can be maximised by building up a customised NTM spectrum database

    Recurrences of multidrug‐resistant tuberculosis: Strains involved, within‐host diversity, and fine‐tuned allocation of reinfections

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    Recurrent tuberculosis occurs due to exogenous reinfection or reactivation/persistence. We analysed 90 sequential MDR Mtb isolates obtained in Argentina from 27 patients with previously diagnosed MDR-TB that recurred in 2018 (1–10 years, 2–10 isolates per patient). Three long-term predominant strains were responsible for 63% of all MDR-TB recurrences. Most of the remaining patients were infected by strains different from each other. Reactivation/persistence of the same strain caused all but one recurrence, which was due to a reinfection with a predominant strain. One of the prevalent strains showed marked stability in the recurrences, while in another strain higher SNP-based diversity was observed. Comparisons of intra- versus inter-patient SNP distances identified two possible reinfections with closely related variants circulating in the community. Our results show a complex scenario of MDR-TB infections in settings with predominant MDR Mtb strains.Fil: Pérez Lago, Laura. Hospital General Universitario Gregorio Marañón (hosp Gral Univ G. Marañón); EspañaFil: Monteserin, Johana. Administración Nacional de Laboratorio e Institutos de Salud "Dr. Carlos G. Malbrán". Instituto Nacional de Epidemiologia. Departamento de Investigación; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Paul, Roxana Elizabeth. Administración Nacional de Laboratorio e Institutos de Salud "Dr. Carlos G. Malbrán". Instituto Nacional de Epidemiologia. Departamento de Investigación; ArgentinaFil: Maus, Sandra R.. Hospital General Universitario Gregorio Marañón (hosp Gral Univ G. Marañón); EspañaFil: Yokobori, Noemí. Administración Nacional de Laboratorio e Institutos de Salud "Dr. Carlos G. Malbrán". Instituto Nacional de Epidemiologia. Departamento de Investigación; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Herranz, Marta. Hospital General Universitario Gregorio Marañón (hosp Gral Univ G. Marañón); EspañaFil: Sicilia, Jon. Hospital General Universitario Gregorio Marañón (hosp Gral Univ G. Marañón); EspañaFil: Acosta, Fermín Eloy. Hospital General Universitario Gregorio Marañón (hosp Gral Univ G. Marañón); EspañaFil: Fajardo, Sandra. Centro Regional de estudios Bioquímicos de la Tuberculosis; ArgentinaFil: Chiner Oms, Álvaro. Consejo Superior de Investigaciones Científicas; EspañaFil: Matteo, Mario José. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Tisioneumonología "raúl F. Vaccarezza".; ArgentinaFil: Símboli, Norberto Fabián. Administración Nacional de Laboratorio e Institutos de Salud "Dr. Carlos G. Malbrán". Instituto Nacional de Epidemiologia. Departamento de Investigación; ArgentinaFil: Comas, Iñaki. Consejo Superior de Investigaciones Científicas; EspañaFil: Muñoz, Patricia. Hospital General Universitario Gregorio Marañón (hosp Gral Univ G. Marañón); España. Universidad Complutense de Madrid; EspañaFil: López, Beatriz. Administración Nacional de Laboratorio e Institutos de Salud "Dr. Carlos G. Malbrán". Instituto Nacional de Epidemiologia. Departamento de Investigación; ArgentinaFil: Ritacco, Gloria Viviana. Administración Nacional de Laboratorio e Institutos de Salud "Dr. Carlos G. Malbrán". Instituto Nacional de Epidemiologia. Departamento de Investigación; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: García de Viedma, Darío. Hospital General Universitario Gregorio Marañón (hosp Gral Univ G. Marañón); Españ
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