Feasibility study to characterize the production of antineutrons in high energy pppp collisions through charge exchange interactions

Simulations to evaluate the feasibility of $\bar{n}$ identification and kinematic characterization via the hadronic charge exchange (CEX) interaction $n+\bar{n}\rightarrow p+\bar{p}$ are reported. The target neutrons are those composing the silicon nuclei of which inner tracking devices present in LHC experiments are made. Simulations of $pp$ collisions in PYTHIA were carried out at different energies to investigate $\bar{n}$ production and the expected $\bar{n}$ energy spectra. Then, two types of GEANT4 simulations were performed, placing an $\bar{n}$ point source at the ALICE primary vertex as a working example. In the first simulation, the $E_k$ was kept at an arbitrary (1 GeV) fix value to develop an $\bar{n}$ identification and kinematics reconstruction protocol. The second GEANT4 simulation used the resulting PYTHIA at $\sqrt{s_{pp}}=13$ TeV $\bar{n}$ energy spectra. In both simulations, the occurrence of CEX interactions was identified by the unique outgoing $\bar{p}$. The simplified simulation allowed to estimate a 0.11% CEX-interaction identification efficiency at $E_k = 1$ GeV. The $p$ CEX-partner identification is challenging because of the presence of silicon nucleus-fragmentation protons. Momentum correlations between the $\bar{n}$ and all possible $\bar{p}p$ pairs showed that $p$ CEX-partner identification and $\bar{n}$ kinematics reconstruction corresponds to minimal momentum-loss events. The use of ITS $dE/dx$ information is found to improve $\bar{n}$ identification and kinematic characterization in both simulations. The final protocol applied to the realistic simulation resulted in a $\bar{n}$ identification and kinematic reconstruction efficiency of 0.006%, based solely on $\bar{p}p$ pair observable. Thus, the expected rate of identified and kinematically reconstructed $\bar{n}$ should lie in the order of 100,000 per second, illustrating the feasibility of the method.Comment: 6 pages, 11 figure

Muticenter spanish study for perioperative stroke risk prediction after isolated coronary artery bypass surgery: The PACK2 score

[ES] Objetivos: Desarrollar un modelo predictivo multivariante del accidente cerebrovascular (ACV) intrahospitalario tras cirugía de bypass coronario. Métodos: Veintiséis mil trescientos cuarenta y siete pacientes incluidos en el estudio procedentes de 21 bases de datos de hospitales españoles. El análisis de regresión logística fue utilizado para predecir el riesgo de ACV perioperatorio (ictus o accidente isquémico transitorio). El modelo predictivo fue desarrollado a partir de un subgrupo de datos «de prueba» y validado en otro subgrupo independiente, ambos seleccionados aleatoriamente del total de la muestra. La capacidad predictiva del modelo se relacionó con el área bajo la curva ROC (ABC). Las variables consideradas fueron: preoperatorias (edad, sexo, diabetes mellitus, hipertensión arterial, ACV previo, insuficiencia cardiaca y/o fracción de eyección del ventrículo izquierdo < 40%, prioridad de la intervención no electiva, arteriopatía extracardiaca, insuficiencia renal crónica y/o creatininemia &#8805; 2 mg/dl y fibrilación auricular) e intraoperatorias (cirugía coronaria con/sin circulación extracorpórea). Resultados: Incidencia global de ACV perioperatorio 1,38%. La prioridad no electiva de la cirugía (priority; OR = 2,32), arteriopatía extracardiaca (arteriopathy; OR = 1,37), insuficiencia cardiaca (cardiac; OR = 3.64) e insuficiencia renal crónica (kidney; OR = 6,78) fueron identificados como factores de riesgo independientes de ACV perioperatorio en los modelos uni y multivariante en el subgrupo de prueba; p < 0,0001; ABC = 0,77, IC del 95%, 0,73-0,82. El modelo PACK2 de ACV perioperatorio tras cirugía de bypass coronario se estableció con 1 punto para cada ítem, excepto para la insuficiencia renal crónica que se le otorgaron 2 puntos (rango 0-5 puntos); ABC = 0,76, IC del 95%, 0,72-0,80. En pacientes con puntuación PACK2 &#8805; 2 puntos, la cirugía coronaria sin circulación extracorpórea redujo la incidencia de ACV en un 2,3% cuando se comparó con el grupo con cirugía realizada con circulación extracorpórea. Conclusiones: La escala de riesgo PACK2 muestra una buena capacidad predictiva en los datos analizados y podría ser útil en la toma de decisiones y selección de pacientes de la práctica clínica.[EN] Objectives: To develop a multivariate predictive risk score of perioperative in-hospital stroke after coronary artery bypass grafting (CABG) surgery. Methods: A total of 26,347 patients were enrolled from 21 Spanish hospital databases. Logistic regression analysis was used to predict the risk of perioperative stroke (stroke or transient ischaemic attack). The predictive scale was developed from a training set of data and validated by an independent test set, both selected randomly from the global sample. The assessment of the accuracy of prediction was related to the area under the ROC curve (AUC). The variables considered were: preoperative (age, gender, diabetes mellitus, arterial hypertension, previous stroke, cardiac failure and/or left ventricular ejection fraction < 40%, non-elective priority of surgery, extracardiac arteriopathy, chronic kidney failure and/or serum creatinine ≥2 mg/dl, and atrial fibrillation) and intra-operative (on/off-pump). Results: The overall perioperative stroke incidence was 1.38%. Non-elective priority of surgery (priority; OR = 2.32), vascular disease (arteriopathy; OR = 1.37), heart failure (cardiac; OR = 3.64), and chronic kidney failure (kidney; OR = 6.78) were found to be independent risk factors for perioperative stroke in uni- and multivariate models in the training set of data; P < .0001; AUC = 0.77, 95% CI 0.73–0.82. The PACK2 stroke CABG score was established with 1 point for each item, except for chronic kidney failure with 2 points (range 0–5 points); AUC = 0.76, 95% CI 0.72–0.80. In patients with PACK2 score ≥2 points, off-pump reduced perioperative stoke incidence by 2.3% when compared with on-pump CABG. Conclusions: PACK2 risk scale shows good predictive accuracy in the data analysed and could be useful in clinical practice for decision making and patient selection.Martín, E.; Hornero, F.; Rodríguez, R.; Castellà, M.; Porras, C.; Romero, B.; Maroto, L.... (2014). Estudio multicéntrico español para la predicción del riesgo perioperatorio de accidente cerebrovascular tras cirugía de bypass coronario aislada: el modelo PACK2. Cirugia Cardiovascular. 21(3):175-180. doi:10.1016/j.circv.2014.02.009S17518021

Chia seeds products: an overview

Chia, Salvia hispanica L., is a medicinal and dietary plant species used since ancient times by Mayan and Aztec. Its product is a dry indehiscent fruit which is commonly called seed. In recent times, there was an increasing attention and diffusion of the seeds of the plant for their health benefits and uses in cooking. In fact, seeds are a rich source of nutrients first of all the polyunsaturated omega-3 fatty acids that protect from inflammation, enhance cognitive performance and reduce the level of cholesterol. Seeds are also rich in polyphenols derived from caffeic acid that are antioxidant compounds protecting the body from free radicals, aging and cancer. In addition, carbohydrate based fibers, present at high concentration levels, are associated with reducing inflammation, lowering cholesterol and regulating bowel function. This review summarizes the current knowledge on the phytochemistry and pharmacological properties of the seeds of this plant, with special emphasis on the nutritional, and phytochemical analysis of the plant, including the recently developed metabolomic studie

Tiempos para pensar : investigación social y humanística hoy en Venezuela. Tomo II

En nuestros tiempos, hacer investigación en Ciencias Sociales y Humanidades e intentar aportar pensamiento crítico es un hacer personal y también una tarea colectiva que se gesta en el intercambio y en el encuentro, en el debate y en la puesta en común de visiones, análisis, puntos de partida y espacios que se recorren. Hay desafíos del nuevo tiempo que son desafíos de las sociedades, e interpelan a la producción de conocimiento social y humano, le proponen preguntas y encomiendas, exigen que responda a sus demandas éticas y epistémicas desde el Sur, piden que se construyan saberes alternativos, decoloniales, que expliquen, acompañen y prefiguren la emancipación. Este libro, que cuenta con dos tomos, encara este desafío con rigurosidad y espíritu crítico

Weaning from mechanical ventilation in intensive care units across 50 countries (WEAN SAFE): a multicentre, prospective, observational cohort study

International audienceBackground: Current management practices and outcomes in weaning from invasive mechanical ventilation are poorly understood. We aimed to describe the epidemiology, management, timings, risk for failure, and outcomes of weaning in patients requiring at least 2 days of invasive mechanical ventilation. Methods: WEAN SAFE was an international, multicentre, prospective, observational cohort study done in 481 intensive care units in 50 countries. Eligible participants were older than 16 years, admitted to a participating intensive care unit, and receiving mechanical ventilation for 2 calendar days or longer. We defined weaning initiation as the first attempt to separate a patient from the ventilator, successful weaning as no reintubation or death within 7 days of extubation, and weaning eligibility criteria based on positive end-expiratory pressure, fractional concentration of oxygen in inspired air, and vasopressors. The primary outcome was the proportion of patients successfully weaned at 90 days. Key secondary outcomes included weaning duration, timing of weaning events, factors associated with weaning delay and weaning failure, and hospital outcomes. This study is registered with ClinicalTrials.gov, NCT03255109. Findings: Between Oct 4, 2017, and June 25, 2018, 10 232 patients were screened for eligibility, of whom 5869 were enrolled. 4523 (77·1%) patients underwent at least one separation attempt and 3817 (65·0%) patients were successfully weaned from ventilation at day 90. 237 (4·0%) patients were transferred before any separation attempt, 153 (2·6%) were transferred after at least one separation attempt and not successfully weaned, and 1662 (28·3%) died while invasively ventilated. The median time from fulfilling weaning eligibility criteria to first separation attempt was 1 day (IQR 0–4), and 1013 (22·4%) patients had a delay in initiating first separation of 5 or more days. Of the 4523 (77·1%) patients with separation attempts, 2927 (64·7%) had a short wean (≤1 day), 457 (10·1%) had intermediate weaning (2–6 days), 433 (9·6%) required prolonged weaning (≥7 days), and 706 (15·6%) had weaning failure. Higher sedation scores were independently associated with delayed initiation of weaning. Delayed initiation of weaning and higher sedation scores were independently associated with weaning failure. 1742 (31·8%) of 5479 patients died in the intensive care unit and 2095 (38·3%) of 5465 patients died in hospital. Interpretation: In critically ill patients receiving at least 2 days of invasive mechanical ventilation, only 65% were weaned at 90 days. A better understanding of factors that delay the weaning process, such as delays in weaning initiation or excessive sedation levels, might improve weaning success rates. Funding: European Society of Intensive Care Medicine, European Respiratory Society