Los primeros años de la década de 1980 en Latinoamérica: ¿otra vez los años treinta?

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Relações norte - sul: o componente econômico

Este trabalho apresentará um quadro geral contendo uma visão das relações económicas Norte-Sul, que se espera venha a facilitar a análise científica positiva, e que contribua em direção a prescrições normativas com vistas à tendência desejável nas relações Norte-Sul no futuro

Carbapenem resistance in Enterobacterales bloodstream infections among children with cancer or post-haematopoietic stem cell transplant: a retrospective cohort study

Background Risk factors for carbapenem resistance in Enterobacterales bloodstream infections among children with cancer or post-HSCT have not been thoroughly explored. Methods All children with cancer or post-HSCT who developed Enterobacterales bloodstream infections in two cancer referral centres in major Colombian cities between 2012 and 2021 were retrospectively examined. When the infection episode occurred, carbapenem resistance mechanisms were evaluated according to the available methods. Data were divided in a training set (80%) and a test set (20%). Three internally validated carbapenem-resistant Enterobacterales (CRE) prediction models were created: a multivariate logistic regression model, and two data mining techniques. Model performances were evaluated by calculating the average of the AUC, sensitivity, specificity and predictive values. Results A total of 285 Enterobacterales bloodstream infection episodes (229 carbapenem susceptible and 56 carbapenem resistant) occurred [median (IQR) age, 9 (3.5–14) years; 57% male]. The risk of CRE was 2.1 times higher when the infection was caused by Klebsiella spp. and 5.8 times higher when a carbapenem had been used for ≥3 days in the previous month. A model including these two predictive variables had a discriminatory performance of 77% in predicting carbapenem resistance. The model had a specificity of 97% and a negative predictive value of 81%, with low sensitivity and positive predictive value. Conclusions Even in settings with high CRE prevalence, these two variables can help early identification of patients in whom CRE-active agents are unnecessary and highlight the importance of strengthening antibiotic stewardship strategies directed at preventing carbapenem overuse.Q1Q1Los factores de riesgo de resistencia a los carbapenémicos en las infecciones del torrente sanguíneo por Enterobacterales entre niños con cáncer o después de un TCMH no se han explorado a fondo. Métodos Se examinaron retrospectivamente todos los niños con cáncer o post-TCMH que desarrollaron infecciones del torrente sanguíneo por Enterobacterales en dos centros de referencia de cáncer en las principales ciudades de Colombia entre 2012 y 2021. Cuando ocurrió el episodio de infección, se evaluaron los mecanismos de resistencia a los carbapenémicos según los métodos disponibles. Los datos se dividieron en un conjunto de entrenamiento (80%) y un conjunto de prueba (20%). Se crearon tres modelos de predicción de Enterobacterales resistentes a carbapenémicos (CRE) validados internamente: un modelo de regresión logística multivariante y dos técnicas de minería de datos. El rendimiento del modelo se evaluó calculando el promedio del AUC, la sensibilidad, la especificidad y los valores predictivos. Resultados Se produjeron un total de 285 episodios de infección del torrente sanguíneo por Enterobacterales (229 susceptibles a carbapenémicos y 56 resistentes a carbapenémicos) [mediana de edad (RIQ), 9 (3,5 a 14) años; 57% hombres]. El riesgo de CRE fue 2,1 veces mayor cuando la infección fue causada por Klebsiella spp. y 5,8 veces mayor cuando se había utilizado un carbapenem durante ≥3 días en el mes anterior. Un modelo que incluía estas dos variables predictivas tuvo un rendimiento discriminatorio del 77% en la predicción de la resistencia a los carbapenémicos. El modelo tuvo una especificidad del 97% y un valor predictivo negativo del 81%, con baja sensibilidad y valor predictivo positivo. Conclusiones Incluso en entornos con una alta prevalencia de CRE, estas dos variables pueden ayudar a la identificación temprana de pacientes en quienes los agentes activos de CRE son innecesarios y resaltar la importancia de fortalecer las estrategias de administración de antibióticos dirigidas a prevenir el uso excesivo de carbapenémicos.N/AS

In-beam tests of the AMS RICH prototype with 20 A GeV/c secondary ions

Abstract A prototype of the AMS Cherenkov imager (RICH) has been tested by means of a low intensity 20 GeV /c per nucleon ion beam coming from the fragmentation of a primary beam of Pb ions. Data have been collected for charges

Measurement of the cosmic ray spectrum above 4×10184{\times}10^{18} eV using inclined events detected with the Pierre Auger Observatory

A measurement of the cosmic-ray spectrum for energies exceeding $4{\times}10^{18}$ eV is presented, which is based on the analysis of showers with zenith angles greater than $60^{\circ}$ detected with the Pierre Auger Observatory between 1 January 2004 and 31 December 2013. The measured spectrum confirms a flux suppression at the highest energies. Above $5.3{\times}10^{18}$ eV, the "ankle", the flux can be described by a power law $E^{-\gamma}$ with index $\gamma=2.70 \pm 0.02 \,\text{(stat)} \pm 0.1\,\text{(sys)}$ followed by a smooth suppression region. For the energy ($E_\text{s}$) at which the spectral flux has fallen to one-half of its extrapolated value in the absence of suppression, we find $E_\text{s}=(5.12\pm0.25\,\text{(stat)}^{+1.0}_{-1.2}\,\text{(sys)}){\times}10^{19}$ eV.Comment: Replaced with published version. Added journal reference and DO

Energy Estimation of Cosmic Rays with the Engineering Radio Array of the Pierre Auger Observatory

The Auger Engineering Radio Array (AERA) is part of the Pierre Auger Observatory and is used to detect the radio emission of cosmic-ray air showers. These observations are compared to the data of the surface detector stations of the Observatory, which provide well-calibrated information on the cosmic-ray energies and arrival directions. The response of the radio stations in the 30 to 80 MHz regime has been thoroughly calibrated to enable the reconstruction of the incoming electric field. For the latter, the energy deposit per area is determined from the radio pulses at each observer position and is interpolated using a two-dimensional function that takes into account signal asymmetries due to interference between the geomagnetic and charge-excess emission components. The spatial integral over the signal distribution gives a direct measurement of the energy transferred from the primary cosmic ray into radio emission in the AERA frequency range. We measure 15.8 MeV of radiation energy for a 1 EeV air shower arriving perpendicularly to the geomagnetic field. This radiation energy -- corrected for geometrical effects -- is used as a cosmic-ray energy estimator. Performing an absolute energy calibration against the surface-detector information, we observe that this radio-energy estimator scales quadratically with the cosmic-ray energy as expected for coherent emission. We find an energy resolution of the radio reconstruction of 22% for the data set and 17% for a high-quality subset containing only events with at least five radio stations with signal.Comment: Replaced with published version. Added journal reference and DO

Measurement of the Radiation Energy in the Radio Signal of Extensive Air Showers as a Universal Estimator of Cosmic-Ray Energy

We measure the energy emitted by extensive air showers in the form of radio emission in the frequency range from 30 to 80 MHz. Exploiting the accurate energy scale of the Pierre Auger Observatory, we obtain a radiation energy of 15.8 \pm 0.7 (stat) \pm 6.7 (sys) MeV for cosmic rays with an energy of 1 EeV arriving perpendicularly to a geomagnetic field of 0.24 G, scaling quadratically with the cosmic-ray energy. A comparison with predictions from state-of-the-art first-principle calculations shows agreement with our measurement. The radiation energy provides direct access to the calorimetric energy in the electromagnetic cascade of extensive air showers. Comparison with our result thus allows the direct calibration of any cosmic-ray radio detector against the well-established energy scale of the Pierre Auger Observatory.Comment: Replaced with published version. Added journal reference and DOI. Supplemental material in the ancillary file