Structure and bonding in WCn (n = 2–5) clusters

Stochastic explorations of the configurational spaces for WC n (n = 2–5) clusters lead to densely populated spin states at each molecularity. We found 8, 16, 42, and 68 well-defined minima for n = 2, 3, 4, 5, respectively, in spin states ranging from singlets to quintuplets. The lowest energy isomers are triplets in all cases, except for n = 2 where there is competition between a quintuplet and a triplet state for the global minimum. The transition from planar to 3D structural preferences occurs between n = 4 and n = 5. For the global minima, the structures may be considered as the result of the interaction between two fragments: a tungsten cation and a covalently bonded anionic carbon chain. We found that spin–orbit (SO) effects reduce energy differences among isomers. Likewise, SO effects diminish as a function of the carbon content in the clusters to the point that for n = 5 they become negligible

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

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

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

Efectos del empacado en atmósferas modificadas para la conservación de arepa de maíz

Introduction. In Colombia corn arepas are an ethnic type of food and a basic product of the food basket. One of the main inconvenients associated to their conservation is their deterioration by molds and yeast, which limits the product´s life to five days. There is a lack of knowledge concerning the importance of managing the cold chain, and therefore it is not being properly applied in the arepa´s commercialization. Objective. Evaluating the following aspects: combined conservation systems by the use of gas mixtures (100% CO2 , 40% CO2 /60% N2 and vacuum), Packaging structures of intermediate and high barrier, to gases, Temperature control in storage, aiming to increase the arepa´s life for its national and international commercialization. Methodology. Microbiological, sensorial and physical-chemical analysis were performed in order to determine the life of the product, according to NTC 5372 regulation, during 65 days, evaluating the arepa´s stability at room temperature, refrigerated and under fluctuating conditions, mixing room temperature and refrigeration. The experimental design consisted of the evaluation of the effect of the three storage conditions combined with two packaging structures: high barrier (PET/LDPE/EVOH/LDPE top and BOPA/EVOH/BOPA/LDPE bottom in 150 microns) and intermediate (PET/LDPE/EVOH/LDPE top and BOPA/EVOH/BOPA/LDPE bottom in 130 microns) packaging gases (100% CO2, 40% CO2 /60% N2 and Vacuum). Results. The 100% CO2 combination intermediate barrier- kept the microbiological and sensorial characteristics during 9 days at room temperature (25°C ± 2°C), 28 days under fluctuating conditions and 5 days refrigerated (5°C ± 2°C), thus increasing the arepa´s stability an 80% when stored at room temperature, and 100% in refrigeration. Conclusion. The evaluation of the different treatments used to conserve corn arepas permitted to establish that treatment number three, in which a 100% CO2 atmosphere and an intermediate barrier package were used, conserved the quality characteristics of the product for a longer time.Introdução. Na Colômbia a arepa de milho é um alimento étnico e um produto básico da canastra familiar. Um dos principais inconvenientes associados a sua conservação é a deterioração por mofos e fermentos que limitam a vida útil do produto a cinco dias. Atualmente existe desconhecimento da importância do manejo da corrente de frio, razão pela qual geralmente não é aplicado na comercialização. Objetivo. Avaliar os seguintes aspectos: Sistemas combinados de conservação utilizando misturas de gases (100% CO2 , 40% CO2 /60% N2 e Esvaziamento), Estruturas de empacotamento de barreira intermédia e alta a gases, Controle da temperatura de armazenamento; com o fim de aumentar a vida útil do produto para sua comercialização a nível nacional e de exportação. Metodologia. Para determinar a vida útil se realizaram análise microbiológicos, sensoriais e físico-químicos à arepa, segundo o estabelecido nas normas NTC 5372, durante 65 dias avaliando a estabilidade do produto a temperatura ambiente, refrigeração e a combinação destas (flutuante). O desenho experimental consistiu em avaliar o efeito das três condições de armazenamento em combinação com duas estruturas de empacotamentos: barreira alta (tampa PET/LDPE/EVOH/ LDPE e fundo BOPA/EVOH/BOPA/LDPE em 150 micras) e intermédia (tampa PET/PA/LDPE fundo PA/LDPE 130 micras), gases de embalados (100% CO2 , 40% CO2 /60% N2 e Esvaziamento). Resultados. Determinou-se que a combinação de 100% CO2 - barreira intermédia, mantinha as características microbiológicas e sensoriais durante 9 dias a temperatura ambiente (25°C ± 2°C), 28 dias a temperatura flutuante e 55 dias em refrigeração (5°C ± 2°C); aumentando num 80% a estabilidade da arepa armazenada ao ambiente e num 100% sua conservação em refrigeração. Conclusão. A avaliação dos diferentes tratamentos utilizados para a conservação da arepa de milho, permitiu estabelecer que o tratamento três, no que se emprego uma atmosfera de 100% CO2 e empacotamento de barreira intermédia, prolongo por maior tempo as características de qualidade do produto.Introducción. En Colombia la arepa de maíz es un alimento étnico y un producto básico de la canasta familiar. Uno de los principales inconvenientes asociados a su conservación es el deterioro por mohos y levaduras que limitan la vida útil del producto a cinco días. Actualmente existe desconocimiento de la importancia del manejo de la cadena de frío, razón por la cual generalmente no es aplicado en la comercialización. Objetivo. Evaluar aspectos como: sistemas combinados de conservación utilizando mezclas de gases (100% CO2, 40% CO2 /60% N2 y Vacío), estructuras de empaque de barrera intermedia y alta a gases, control de la temperatura de almacenamiento; con el fin de aumentar la vida útil del producto para su comercialización a nivel nacional y de exportación. Metodología. Para determinar la vida útil se realizaron análisis microbiológicos, sensoriales y fisicoquímicos a la arepa, según lo establecido en la normativa NTC 5372, durante 65 días evaluando la estabilidad del producto a temperatura ambiente, refrigeración y la combinación de estas (fluctuante). El diseño experimental consistió en evaluar el efecto de las tres condiciones de almacenamiento en combinación con dos estructuras de empaques: barrera alta (tapa PET/LDPE/EVOH/LDPE y fondo BOPA/ EVOH/BOPA/LDPE en 150 micras) e intermedia (tapa PET/PA/LDPE fondo PA/LDPE 130 micras), gases de envasados (100% CO2, 40% CO2 /60% N2 y Vacío). Resultados. Se determinó que la combinación de 100% CO2 - barrera intermedia, mantenía las características microbiológicas y sensoriales durante 9 días a temperatura ambiente (25°C ± 2°C), 28 días a temperatura fluctuante y 55 días en refrigeración (5°C ± 2°C); aumentando en un 80% la estabilidad de la arepa almacenada al ambiente y en un 100% su conservación en refrigeración. Conclusión. La evaluación de los diferentes tratamientos utilizados para la conservación de la arepa de maíz, permitió establecer que el tratamiento tres, en el que se empleo una atmósfera de 100% CO2 y empaque de barrera intermedia, prolongó por mayor tiempo las características de calidad del producto

Estudio socioeconómico del Sector Nueva Colombia del municipio de Chiquinquirá, Boyacá, a partir de variables de la contabilidad social

Spa: El presente documento contiene la aplicación conceptual de la contabilidad social, metodología desarrollada por Jack Araújo en el libro Contabilidad Social (1995), este autor fue el referente con el propósito de estudiar las características demográficas y económicas del sector Nueva Colombia, ubicado en el barrio El Bosque, del municipio de Chiquinquirá, departamento de Boyacá.PregradoContador Públic