Magnetic properties of nanoscale crystalline maghemite obtained by a new synthetic route

AbstractIn this work we describe the synthesis and characterization of maghemite nanoparticles obtained by a new synthetic route. The material was synthesized using triethylamine as a coprecipitation agent in the presence of the organic ligand N,N′-bis(3,5-di-tert-butyl-catechol)-2,4-diaminotoluene (LCH3). Mössbauer spectrum at 4K shows typical hyperfine parameters of maghemite and Transmission Electron Microscopy images reveal that the nanoparticles have a mean diameter of 3.9nm and a narrow size distribution. AC magnetic susceptibility in zero field presents an Arrhenius behavior with unreasonable relaxation parameters due to the strong influence of dipolar interaction. In contrast when the measurements are performed in a 1kOe field, the effect of dipolar interactions becomes negligible and the obtained parameters are in good agreement with the static magnetic properties. The dynamic energy barrier obtained from the AC susceptibility results is larger than the expected from the average size observed by HRTEM results, evidencing the strong influence of the surface contribution to the anisotropy

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

Produtividade de vinagreira, pimenta rosa e carobinha cultivadas em sucessão a mucuna preta e feijão de porco

RESUMO O uso de adubos verdes e/ou de plantas de cobertura é uma técnica que vem sendo difundida para o cultivo de espécies medicinais, por garantir a sustentabilidade do solo agrícola, ser flexível em seu uso e por melhorar a atividade biológica do solo. O objetivo do trabalho foi avaliar o uso de culturas de cobertura para incrementar a produção de massa de plantas de vinagreira, pimenta rosa e carobinha. Foram avaliadas duas espécies de leguminosas tropicais (mucuna preta e feijão de porco) como cobertura do solo e uma testemunha (sem cultura de cobertura) e três espécies medicinais (vinagreira, pimenta rosa e carobinha). O experimento foi arranjado em esquema de parcelas subdivididas, tendo nas parcelas as coberturas vegetais e nas subparcelas, as plantas medicinais. As plantas para a cobertura vegetal foram propagadas por semeadura direta no local de cultivo, enquanto as medicinais foram transplantadas diretamente entre a palhada da cobertura vegetal. A produção da mucuna preta foi de 8,37 t ha-1 de massa seca e do feijão de porco, de 14,37 t ha-1 de massa seca. O uso das culturas de cobertura contribuiu para uma maior biomassa microbiana do solo. As produções de massas frescas de folhas, caules e frutos de vinagreira e de frutos da pimenta rosa foram maiores quando cultivadas em sucessão às coberturas vegetais do solo, independente da espécie. As produções da carobinha foram semelhantes quando cultivadas em áreas com ou sem a cobertura. Visando à maior produtividade da vinagreira e pimenta rosa, são indicadas as culturas antecessoras feijão de porco e mucuna preta

PRAPRAG: software para planejamento racional de máquinas agrícolas PRAPRAG: software for rational planning of agricultural machines

O software PRAPRAG é uma ferramenta de escolha de máquinas e implementos agrícolas que apresentam o menor custo por área ou por quantidade produzida, bem como, faz o planejamento de aquisição das máquinas para a propriedade agrícola, do ponto de vista técnico e econômico. Foi utilizada a linguagem de programação Borland Delphi 3.0 e, a partir de prospectos das máquinas e implementos, criou-se um banco de dados onde o usuário pode cadastrar e modificar suas características de uso. O software mostrou-se uma ferramenta útil e uso amigável. O software proporciona maior rapidez, segurança e confiabilidade ao processo produtivo e econômico das propriedades, na seleção e aquisição de conjuntos mecanizados agrícolas, e na determinação de custos com a mão de obra utilizada.<br>The software PRAPRAG is a tool used for choosing agricultural machines and implements that present the lowest cost per area or produced amount, as well as, to it makes the machines acquisition planning for the agricultural property, from both technical and economical points of view. It was used the programming language Borland Delphi 3.0. From the machine and implement handouts, it was created a database where the user can register and modify their characteristics of use. The software showed to be a useful and friendly tool. The software provides high speed, safety and reliability for the productive and economical process of the properties, at the selection and acquisition of agricultural systems, as well as for the determination of costs with the used labor