A pilot study to test the reliability of OII model atoms with stellar spectroscopy

La espectroscop´ıa cuantitativa puede ser definida como la disciplina que permite inferir par´ametros f´ısicos a partir de la aplicaci´on de herramientas de an´alisis espectrosc´opico a un espectro observado. Actualmente existe una gran cantidad de espectros de alta calidad que permiten el estudio detallado de las propiedades f´ısicas de las estrellas en distintas ventanas espectrales. Para el estudio de las estrellas el espectro observado no es la ´unica herramienta necesaria, el an´alisis cuantitativo requiere de un marco te´orico sobre el cual comparar las observaciones e inferir par´ametros f´ısicos. En la astrof´ısica moderna este marco te´orico es conocido como transporte radiativo y se materializa de manera pr´actica mediante los denominados modelos de atm´osfera. Los modelos de atm´osfera permiten resolver el problema del transporte radiativo en la estrella con el objetivo de crear un espectro estelar sint´etico. Es decir, permiten deducir la forma del espectro que emana del estrella y es medido por nuestros telescopios. Adem´as de consideraciones con respecto a ciertos aspectos macrosc´opicos de la estrella (referentes tanto a la geometr´ıa considerada en el modelado como a los par´ametros f´ısicos fundamentales que caracterizan a la misma). Los mod´elos de atm´osfera necesitan m´odelos at´omicos fiables para representar la interacci´on radiaci´onmateria que sucede en la estrella. El objetivo de este trabajo es el de testear dos m´odelos at´omicos de O ii construidos con el paquete computacional maKe Atoms Simple (KAS) desarrollado por Yeisson Osorio. Las comparaci´on se realizar´a a trav´es del c´alculo de la abundancia de ox´ıgeno en la estrella BD+463474 usando el m´etodo de la curva de crecimiento. Las observaciones (cuyo an´alisis espectrosc´opico fue ya presentado en Garc´ıa-Rojas et al., 2014) fueron realizadas con el espectr´ografo de alta resoluci´on FIES montado en el telescopio NOT en el observatorio del Roque de los Muchachos el 10 de septiembre de 2012. Esta estrella, ubicada en la nebulosa del Capullo, es una buena candidata para el testeo de modelos at´omicos debido a su baja rotaci´on y par´ametros estelares favorables. Con el objetivo de comparar los modelos at´omicos, dos redes de espectros sint´eticos (en los que, fijadas la temperatura efectiva y la gravedad superficial de la estrella, se dejaron variar la abundancia de ox´ıgeno y la microturbulencia) fueron calculados. Para el c´aculo de los espectros se utiliz´o el programa de c´alculo de atm´osferas estelares llamado TLUSTY, el cual fue alimentado con cada modelo at´omico para el c´alculo de cada respectiva red. En este sentido en la secci´on 4 se da un peque˜no acercamiento a la construcci´on de modelos at´omicos. As´ı mismo, en esta secci´on se realizar´a una revisi´on detallada de las principales diferencias entre los dos modelos at´omicos utilizados en nuestro estudio. Cabe destacar, tambi´en, que uno de los objetivos de este trabajo fue desarrollar un paquete computacional en IDL con la finalidad de compatibilizar la salida del programa de c´alculo de espectros sint´eticos con un programa de c´alculo de abundancias desarrollado por Sergio Sim´on-D´ıaz. Este trabajo se inici´o con la selecci´on de una lista preliminar de 46 l´ıneas de absorci´on de O ii. Para la selecci´on se parti´o de una lista de l´ıneas proporcionada por el sistema KAS. De donde se fueron descartando l´ıneas por motivos de contaminaci´on, blending, dificultad para medir su anchura equivalente o problemas en el espectro sint´etico hasta llegar a la lista preliminar de 46 l´ıneas de O ii. La metodolog´ıa utilizada para la selecci´on y c´alculo de contaminaci´on de las l´ıneas se detalla en la secci´on 5. En esta secci´on se desarrolla tambi´en el m´etodo de la curva de crecimiento y el efecto que tienen los distintos par´ametros estelares en el resultado del c´alculo de abundancias. Nuestros an´alisis arrojaron que los modelos utilizados dan resultados en concordancia con los derivados por Garc´ıa-Rojas et al. (2014). Luego de comprobar que los modelos pueden, de manera global, llevar un an´alisis completo de abundancias procedimos a analizar el set de l´ıneas dividido por multipletes. Este acercamiento nos permiti´o analizar la sensibilidad de cada multiplete con respecto a cambios en el m´odelo at´omico, as´ı como tambi´en descubrir problemas en la informaci´on at´omica usada para calcular los espectros sint´eticos. El estudio por multipletes logr´o demostrar principalmente que: el grado de sensibilidad con respecto a cambios en el modelo at´omico depende del multiplete, las l´ıneas m´as fuertes parecen demostrar mayor sensibilidad que las m´as debiles, existen deficiencias en algunos valores de la informaci´on at´omica considerada y que la sensibilidad a cambios en los modelos parece ser menor a microturbulencias mayores. Por ´ultimo nuestros an´alisis permitieron desarrollar una metodolog´ıa que puede ser aplicable para otras estrellas de par´ametros estelares similares con otras especies qu´ımicas y con un n´umero mayor de modelos at´omicos. En la secci´on 6 damos una revisi´on profunda de los resultados m´as importantes de nuestro an´alisis. Mientras que, en la secci´on 7, se desarrollan las conclusiones finales y los futuros curso de acci´on a tomar partiendo de la metodolog´ıa desarrollada

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Memorias del primer Simposio Nacional de Ciencias Agronómicas

Primer simposio nacional de Ciencias Agronómicas: El renacer del espacio de discusión científica para el Agro colombiano

Memorias del primer Simposio Nacional de Ciencias Agronómicas

Primer simposio nacional de Ciencias Agronómicas: El renacer del espacio de discusión científica para el Agro colombiano

Naturaleza urbana. Plataforma de experiencias

Naturaleza Urbana presenta experiencias autogestionadas que, con el tiempo, se han posicionado como ejercicios alternativos de identificación, monitoreo y recuperación de la biodiversidad urbana. En otros casos, el modelo comunidad-gobierno ha permitido desarrollar diagnósticos y propuestas de gestión corresponsables y sistémicas, entendiendo por esto último iniciativas que nacen desde los valores mismos que cada comunidad le atribuye a su biodiversidad. Del mismo modo, se presentan esfuerzos gubernamentales que han enriquecido la visión ambiental de los principales instrumentos de planificación urbana, por ejemplo, integrando la condición propiamente urbana como oportunidad para aumentar la oferta ambiental de la ciudad, fortaleciendo las funciones y procesos de la biodiversidad y revitalizando, con ello, la calidad de vida del entorno urbano. Por su parte, las universidades y los centros de investigación se han sumado a la ola emergente de generación de conocimiento en biodiversidad urbana (fenómeno nacional e internacional), han brindado evidencia científica de su valor para el bienestar humano y han propuesto reflexiones y lineamientos cualitativos de biodiversidad, con miras a hacer del ordenamiento un ejercicio más coherente con cada contexto territorial en particular.Bogotá, D. C., ColombiaInstituto de Investigación de Recursos Biológicos Alexander von Humbold

Urban Nature

Preservation, restoration, monitoring of biodiversity and promotion of native species, in their strict and classical sense, could be unviable strategies in the cities. Management systems such as the protected areas acquire profoundly different connotations and objectives from the traditional ones when thought of in the context of a city. Similarly, although ecological restoration seeks to return to a baseline ecosystem, there is little that we know about the vegetation present on the urban borders of the main Colombian cities prior to the 20th century. Finally, the models for potential distribution of species could produce unreliable results, because their methodological bases were not conceived based on urban dynamics. In this context, to de ne urban biodiversity and what strategy must be applied for its conservation implies a challenge that, beyond being scienti c, is necessarily social and cultural and involves planning and design. Innovation is inevitable.Bogotá, D. C

Stoma-free survival after anastomotic leak following rectal cancer resection: worldwide cohort of 2470 patients

Background: The optimal treatment of anastomotic leak after rectal cancer resection is unclear. This worldwide cohort study aimed to provide an overview of four treatment strategies applied. Methods: Patients from 216 centres and 45 countries with anastomotic leak after rectal cancer resection between 2014 and 2018 were included. Treatment was categorized as salvage surgery, faecal diversion with passive or active (vacuum) drainage, and no primary/secondary faecal diversion. The primary outcome was 1-year stoma-free survival. In addition, passive and active drainage were compared using propensity score matching (2: 1). Results: Of 2470 evaluable patients, 388 (16.0 per cent) underwent salvage surgery, 1524 (62.0 per cent) passive drainage, 278 (11.0 per cent) active drainage, and 280 (11.0 per cent) had no faecal diversion. One-year stoma-free survival rates were 13.7, 48.3, 48.2, and 65.4 per cent respectively. Propensity score matching resulted in 556 patients with passive and 278 with active drainage. There was no statistically significant difference between these groups in 1-year stoma-free survival (OR 0.95, 95 per cent c.i. 0.66 to 1.33), with a risk difference of -1.1 (95 per cent c.i. -9.0 to 7.0) per cent. After active drainage, more patients required secondary salvage surgery (OR 2.32, 1.49 to 3.59), prolonged hospital admission (an additional 6 (95 per cent c.i. 2 to 10) days), and ICU admission (OR 1.41, 1.02 to 1.94). Mean duration of leak healing did not differ significantly (an additional 12 (-28 to 52) days). Conclusion: Primary salvage surgery or omission of faecal diversion likely correspond to the most severe and least severe leaks respectively. In patients with diverted leaks, stoma-free survival did not differ statistically between passive and active drainage, although the increased risk of secondary salvage surgery and ICU admission suggests residual confounding

Stoma-free Survival After Rectal Cancer Resection With Anastomotic Leakage: Development and Validation of a Prediction Model in a Large International Cohort.

Objective:To develop and validate a prediction model (STOMA score) for 1-year stoma-free survival in patients with rectal cancer (RC) with anastomotic leakage (AL).Background:AL after RC resection often results in a permanent stoma.Methods:This international retrospective cohort study (TENTACLE-Rectum) encompassed 216 participating centres and included patients who developed AL after RC surgery between 2014 and 2018. Clinically relevant predictors for 1-year stoma-free survival were included in uni and multivariable logistic regression models. The STOMA score was developed and internally validated in a cohort of patients operated between 2014 and 2017, with subsequent temporal validation in a 2018 cohort. The discriminative power and calibration of the models' performance were evaluated.Results:This study included 2499 patients with AL, 1954 in the development cohort and 545 in the validation cohort. Baseline characteristics were comparable. One-year stoma-free survival was 45.0% in the development cohort and 43.7% in the validation cohort. The following predictors were included in the STOMA score: sex, age, American Society of Anestesiologist classification, body mass index, clinical M-disease, neoadjuvant therapy, abdominal and transanal approach, primary defunctioning stoma, multivisceral resection, clinical setting in which AL was diagnosed, postoperative day of AL diagnosis, abdominal contamination, anastomotic defect circumference, bowel wall ischemia, anastomotic fistula, retraction, and reactivation leakage. The STOMA score showed good discrimination and calibration (c-index: 0.71, 95% CI: 0.66-0.76).Conclusions:The STOMA score consists of 18 clinically relevant factors and estimates the individual risk for 1-year stoma-free survival in patients with AL after RC surgery, which may improve patient counseling and give guidance when analyzing the efficacy of different treatment strategies in future studies

Evaluation of a quality improvement intervention to reduce anastomotic leak following right colectomy (EAGLE): pragmatic, batched stepped-wedge, cluster-randomized trial in 64 countries

Background Anastomotic leak affects 8 per cent of patients after right colectomy with a 10-fold increased risk of postoperative death. The EAGLE study aimed to develop and test whether an international, standardized quality improvement intervention could reduce anastomotic leaks. Methods The internationally intended protocol, iteratively co-developed by a multistage Delphi process, comprised an online educational module introducing risk stratification, an intraoperative checklist, and harmonized surgical techniques. Clusters (hospital teams) were randomized to one of three arms with varied sequences of intervention/data collection by a derived stepped-wedge batch design (at least 18 hospital teams per batch). Patients were blinded to the study allocation. Low- and middle-income country enrolment was encouraged. The primary outcome (assessed by intention to treat) was anastomotic leak rate, and subgroup analyses by module completion (at least 80 per cent of surgeons, high engagement; less than 50 per cent, low engagement) were preplanned. Results A total 355 hospital teams registered, with 332 from 64 countries (39.2 per cent low and middle income) included in the final analysis. The online modules were completed by half of the surgeons (2143 of 4411). The primary analysis included 3039 of the 3268 patients recruited (206 patients had no anastomosis and 23 were lost to follow-up), with anastomotic leaks arising before and after the intervention in 10.1 and 9.6 per cent respectively (adjusted OR 0.87, 95 per cent c.i. 0.59 to 1.30; P = 0.498). The proportion of surgeons completing the educational modules was an influence: the leak rate decreased from 12.2 per cent (61 of 500) before intervention to 5.1 per cent (24 of 473) after intervention in high-engagement centres (adjusted OR 0.36, 0.20 to 0.64; P < 0.001), but this was not observed in low-engagement hospitals (8.3 per cent (59 of 714) and 13.8 per cent (61 of 443) respectively; adjusted OR 2.09, 1.31 to 3.31). Conclusion Completion of globally available digital training by engaged teams can alter anastomotic leak rates. Registration number: NCT04270721 (http://www.clinicaltrials.gov)