Abstract The technique of bending wood by vaporization presents itself as a viable option for curvilinear structural projects, such as gridshells. Coniferous woods are often used in roof structures because, in addition to the desired relationship between mechanical strength and density, they allow the complete treatment of the cross-section of the piece. However, characteristics such as the predominance of sapwood or heartwood and the presence of defects are variables that affect structural performance. The aim of this study was to evaluate the bending limit of Acrocarpus laxinifloius (Indian cedar) veneers with a bending radius of 21 cm at different thicknesses. The impact of the predominance of sapwood or heartwood and the presence of defects on the bending strength was also investigated. The literature indicates that plastic flexibilization by steam occurs at 100°C, with 2.4 minutes for each millimeter of lamella thickness, which were the parameters considered in this study. The statistical analysis indicated a thickness limit of 8 mm for the lamellae to bend and the greater presence of sapwood or heartwood, as well as wood defects, did not significantly affect the bending force. projects gridshells because density crosssection cross section piece However performance Indian cedar 2 thicknesses investigated 100C C 100 100°C 24 4 2. force 10 1

Resumo Atécnica de vergamento da madeira por vaporização se apresenta como opção viável para projetos de estruturas curvilíneas, como as gridshells. Madeiras coníferas são comumente adotadas em estruturas de cobertura, pois além da desejada relação entre resistência mecânica e densidade, permitem o completo tratamento da seção transversal da peça. Entretanto, características como a predominância de alburno ou de cerne e a presença de defeitos são variáveis que afetam o desempenho estrutural. O objetivo deste estudo foi avaliar o limite de vergamento de lamelas de Acrocarpus flaxinifloius (cedro indiano) com raio de curvatura de 21 cm em diferentes espessuras. Também se investigou o impacto da predominância de alburno ou cerne e da presença de defeitos na força de vergamento. A literatura indica que a flexibilização plástica por vapor ocorre a 100°C, com 2,4 minutos para cada milímetro de espessura da lamela, parâmetros estes considerados neste estudo. A análise estatística indicou o limite de 8 mm de espessura para o vergamento das lamelas e a maior presença de alburno ou de cerne, bem como os defeitos da madeira, não afetou significativamente a força de vergamento. curvilíneas gridshells cobertura densidade peça Entretanto estrutural cedro indiano 2 espessuras 100C C 100 100°C 24 4 2, lamela 10 1

ABSTRACT The production process of non-centrifuged cane sugar (NCS) involves a significant release of steam and heat due to the evaporation of cane juices in saucepans over a solid fuel oven. This results in a warm and moisture-saturated environment, which can be suffocating for workers. This study aimed to evaluate the bioclimatic behavior of an NCS processing facility, based on the wet bulb globe temperature (WBGT) index. In addition, solutions are suggested to mitigate possible adverse effects of heat stress. This evaluation utilized computational simulations to determine the thermal comfort perceived by the workers. The accuracy of simulations was verified against temperature and relative air humidity data collected from the facility. Bioclimatic simulations encompassed twelve treatments, involving modifications to the enclosure on the walls and lantern window, incorporating three types of roof material. The WBGT index was determined by considering the effects of the radiant heat generated by the oven and the natural ventilation area on the facility’s temperature and relative air humidity. This helps to assess the comfort experienced by the workers. The thermal zone of the oven presented heat stress conditions; therefore, rest periods and mechanical ventilation were suggested when dissipating heat and steam through natural ventilation is not possible. For workers exposed to high temperatures and thermal radiation, the use of an aluminized apron and infrared goggles for eye protection was recommended. noncentrifuged non centrifuged (NCS moisturesaturated moisture saturated environment facility (WBGT addition treatments window material facilitys s conditions therefore radiation recommended

RESUMO O processo de produção de rapadura gera alta concentração de vapor e calor devido à evaporação do caldo da cana em panelas sobre forno a combustível sólido. Isso gera um ambiente quente e saturado de umidade que pode ser sufocante para os trabalhadores. Este estudo teve como objetivo avaliar as condições ambientais de uma instalação de processamento de rapadura, com base no Índice de Bulbo Úmido e Temperatura de Globo (IBUTG) e sugerir soluções para mitigar possíveis efeitos adversos do estresse térmico. Esta avaliação utilizou simulação computacional para determinar o conforto térmico dos trabalhadores. A simulação foi validada com dados de temperatura e umidade relativa do ar da instalação. As simulações bioclimáticas foram realizadas em doze tratamentos, modificando o fechamento nas paredes e lanternim, com três tipos de materiais de cobertura. Foi determinado o Índice IBUTG, considerando os efeitos do calor radiante gerado pelo forno, e pela área de ventilação natural sobre a temperatura e umidade relativa do ar no interior da instalação, e seu efeito no conforto dos trabalhadores. A zona térmica do forno apresentou condições de estresse térmico, portanto, foram sugeridos períodos de descanso e ventilação mecânica quando não for possível a evacuação do calor e vapor através da ventilação natural. O uso de avental aluminizado e óculos infravermelhos para proteção ocular foi recomendado para os trabalhadores expostos a altas temperaturas e radiação térmica. sólido IBUTG (IBUTG tratamentos lanternim cobertura portanto

RESUMEN El artículo reflexiona en torno a la adaptación de un modelo comunicacional aplicado en el análisis de experiencias de enseñanza-aprendizaje que vincularon la construcción del conocimiento con el uso de las tecnologías digitales. En este sentido, se analiza un caso de estudio referido a una actividad realizada en el marco de una carrera del área de las Ciencias, Tecnologías, Ingeniería y Matemáticas que, a su vez, incluyó criterios vinculados a las Artes (STEAM, su acrónimo en inglés). Los estudiantes debieron diseñar y construir en grupo un juguete, integrando de manera explícita conceptos vinculados a las áreas citadas. Para su observación se tomaron como punto de partida las cuatro dimensiones conceptuales del modelo: Institucional, Social, Tecnológico e Intermedial. Las primeras conclusiones dan cuenta de la riqueza analítica del modelo y los aportes propositivos para repensar experiencias de características similares. Se determina que el desarrollo de prácticas educativas mediatizadas, con una propuesta pedagógica que incluya la participación-acción de docentes y estudiantes, fortalece la perspectiva transdisciplinar en las carreras STEAM, posibilitando que no sólo se contribuya al aprendizaje de tecnologías digitales, sino que también se impulse la innovación tecnológica bajo la modalidad de talleres Fab Lab físico-virtuales.

ABSTRACT The paper works on the adaptation of a communication model applied to the analysis of teaching-learning experiences that linked the construction of knowledge with the use of digital technologies. In this sense, a case study has been analyzed referred to an activity carried out within the framework of a career in the area of Sciences, Technologies, Engineering, Arts and Mathematics which in turn included criteria linked to the Arts (STEAM, its acronym in English). The students had to design and build a plaything as a group, explicitly integrating concepts linked to the aforementioned areas. The four conceptual dimensions of the model: Institutional, Social, Technological and Intermediate, were taken as a starting point for its observation. The first conclusions show the analytical richness of the model and the propositional contributions to rethink experiences with similar characteristics. It is determined that the development of mediated educational practices, with a pedagogical proposal that includes the participation-action of teachers and students, strengthens the transdisciplinary perspective in STEAM careers, making it possible not only to contribute to the learning of digital technologies, but also to promote technological innovation under the modality of physical-virtual Fab Lab workshops.

RESUMO O artigo reflete sobre a adaptação de um modelo de comunicação aplicado à análise de experiências de ensino-aprendizagem que vinculou a construção do conhecimento o uso de tecnologias digitais. Nesse sentido, foi analisado um estudo de caso referente a uma atividade realizada no âmbito de um curso de graduação na área de Ciências, Tecnologias, Engenharia e Matemática que por sua vez incluiu critérios ligados às Artes (STEAM, na sigla em inglês). Os alunos tiveram que conceber e construir um brinquedo em grupo, integrando explicitamente conceitos ligados às áreas acima mencionadas. Para sua observação, tomaram-se como ponto de partida as quatro dimensões conceituais do modelo: Institucional, Social, Tecnológica e Intermediária. As primeiras conclusões mostram a riqueza analítica do modelo e as contribuições propositivas para repensar experiências com características semelhantes. Conclui-se que o desenvolvimento de práticas educativas mediadas, com uma proposta pedagógica que inclua a participação-ação de professores e alunos, fortalece a perspectiva transdisciplinar nas carreiras STEAM, possibilitando não só contribuir para a aprendizagem das tecnologias digitais, mas também promover a inovação tecnológica na forma de oficinas físico-virtuais Fab Lab.

Abstract: This investigation studied the energy efficiency of a steam system in a hospital, considering the procedure in ASME EA-3-2009 standard. This is the standard for the energy assessment of industrial steam systems and aims to enhance the energy efficiency and sustainability of industrial steam systems by identifying opportunities and providing recommendations to optimize system performance. The obtained boiler energy efficiency was 80.29 %, by applying an energy balance, reaching 15.33 kW for heat losses in the distribution pipes. Two consistent improvement alternatives were proposed, starting by unifying the pipe diameter of the kitchen area of 5 m, generating a reduction of heat loss from 828 to 600 W, which represented a total annual energy saving of around 2.4 GJ/year. The investment cost is USD 47.40, considering the achievement of the break-even point after 9 months, where the insulation of the pipes with glass wool was considered second and it generated a reduction in losses of 5.98 kW, representing a total annual energy saving of about 62.91 GJ/year, which corresponds to approximately USD 1 672. The expenditure for insulating a 49 m pipe amounted to USD 462, factoring in both the NPV calculation and potential savings. The breakeven point was achieved within roughly 4 months, underscoring the economic advantage of implementing the two suggested improvement measures.

Resumen: En esta investigación se analizó la eficiencia energética de un sistema de vapor en un hospital, considerando la norma ASME EA-3-2009. Esta norma se utiliza para la evaluación energética de los sistemas de vapor industriales y busca mejorar la eficiencia energética y la sostenibilidad de estos sistemas identificando oportunidades y proponiendo medidas para optimizar el rendimiento. Se obtuvo una eficiencia energética de la caldera de 80.29 % mediante un balance de energías y las pérdidas de calor en las tuberías de distribución alcanzaron 15.33 kW. Se plantearon dos alternativas de mejora consistentes, iniciando con unificar el diámetro de tubería del área de cocina de 5 m, generando una reducción de pérdida de calor de 828 hasta 600 W, que representó un ahorro de energía anual total de 2.4 GJ/año, aproximadamente. El costo de inversión es de USD 47.40, considerando como alcanzable el punto de equilibrio a los 9 meses, donde se planteó en segundo lugar el aislamiento de las tuberías mediante lana de vidrio y generó la disminución de pérdidas en 5.98 kW, representando un ahorro de energía anual total de alrededor de 62.91 GJ/año, lo que corresponde a USD 1 672, aproximadamente. La inversión para el aislamiento de tuberías con una longitud de 49 m fue de USD 462, considerando el cálculo del VAN y los posibles ahorros, además el punto de equilibrio se alcanza a los 4 meses, aproximadamente, e indica el beneficio económico de aplicar las dos opciones de mejora planteadas.

ABSTRACT Introduction: Cuban crude oil has a high content of ash, sulfur, asphaltenes and a high viscosity, among others, which, when subjected to the combustion process, results in corrosive effects in the heat transfer zones, reducing the useful life of the equipment. Objective: To design a procedure for the introduction of additives, which will increase the useful life of the equipment by improving the energy efficiency of the combustion process. Materials and Methods: It starts from the analysis of the composition and physical-chemical properties of Cuban crude oil and the characterization of the additive. The effectiveness of the additive is evaluated on a laboratory, pilot and industrial scale. The combustion parameters are adjusted and the efficiency of the steam generator is analyzed, with the aim of establishing the required dosage. The corresponding profit/economic cost analysis is carried out. Finally, the procedure is designed to compare with another additive if it exists. Results and Discussion: The procedure includes the determination of the chemical composition and physical-chemical properties of the crude oil used, the effect of the additive and the combustion efficiency. It contemplates not only the analysis of the use of an additive in use, but also the introduction of a new one and the comparison with it. It can be implemented in any industry that uses crude oil as fuel in the combustion process. Conclusions: The procedure provides the methodological indications for the introduction of additives that allow the improvement of the steam generator combustion process.

RESUMEN Introducción: El petróleo crudo cubano tiene un alto contenido de cenizas, azufre, asfaltenos y una alta viscosidad, entre otros, que, al someterse al proceso de combustión, trae como consecuencia efectos corrosivos en las zonas de transferencia de calor, disminuyendo la vida útil de los equipos. Objetivo: Diseñar un procedimiento para la introducción de aditivos, que permitan aumentar la vida útil de los equipos a partir de la mejora de la eficiencia energética del proceso de combustión. Materiales y Métodos: Se parte del análisis de la composición y las propiedades físico-químicas del petróleo crudo cubano y la caracterización del aditivo. Se evalúa la efectividad del aditivo a escala de laboratorio, piloto e industrial. Se ajustan los parámetros de la combustión y se analiza la eficiencia del generador de vapor, con el objetivo de establecer la dosificación requerida. Se realiza el análisis beneficio/costo correspondiente. Por último, el procedimiento tiene concebido la comparación con otro aditivo en caso de que exista. Resultados y Discusión: El procedimiento incluye la determinación de la composición química y las propiedades físico-químicas del petróleo crudo utilizado, el efecto del aditivo y la eficiencia de la combustión. Contempla, no solo el análisis de la utilización de un aditivo en uso, si no también, la introducción de uno nuevo y la comparación con éste. Puede ser implementado en cualquier industria que emplee el petróleo crudo como combustible en el proceso de combustión. Conclusiones: El procedimiento brinda las indicaciones metodológicas para la introducción de aditivos que permitan la mejora del proceso de combustión del generador de vapor.

RESUMEN La investigación propone un laboratorio virtual y las tareas docentes que relaciona la biomecánica con la actividad física y deportiva en la Universidad de Cienfuegos. El “Proyecto Hypathia” se propone transformar los procesos sustantivos de la Universidad de Cienfuegos en los campos en los que se integran las Ciencias-Tecnología-Ingeniería-Matemáticas, pero sesgados por una participación escasa, asistemática de las relaciones interdisciplinarias que abarcan las nuevas tecnologías e incursionan en los simuladores, la robótica manifestaciones del arte que se suman como propuesta creativa en los procesos de investigación, formación de profesionales y de extensión universitaria. Se propone un laboratorio virtual y las tareas docentes que relaciona la biomecánica con la actividad física y deportiva en la Universidad de Cienfuegos. Los resultados logrados en la investigación en gran medida fueron posibles por la implementación de diversos métodos y técnicas de investigación los cuales posibilitaron la fundamentación del tema y la valoración del diseño empleado. La implementación de tareas docentes con enfoque STEAM permitió evaluar el proceso y sus resultados desde la práctica educativa en los estudiantes de segundo año de la facultad de Ciencias de la Cultura Física y el deporte de Cienfuegos.

ABSTRACT The research proposes a virtual laboratory and teaching tasks that relate biomechanics with physical and sports activity at the University of Cienfuegos. The “Hypathia Project” aims to transform the substantive processes of the University of Cienfuegos in the fields in which Sciences-Technology-Engineering-Mathematics are integrated, but biased by a scarce, unsystematic participation in the interdisciplinary relationships that encompass new technologies. and they venture into simulators, robotics, art manifestations that add as a creative proposal to the research processes, training of professionals and university extension. A virtual laboratory and teaching tasks that relate biomechanics with physical and sports activity at the University of Cienfuegos are proposed. The results achieved in the research were largely possible due to the implementation of various research methods and techniques which made it possible to substantiate the topic and evaluate the design used. The implementation of teaching tasks with a STEAM approach allowed the evaluation of the process and its results from educational practice in the second-year students of the Faculty of Physical Culture and Sports Sciences of Cienfuegos.

In the context of a need for finding and enabling alternatives to unequal and extractivist perspectives on development, growth, and human well-being, this positioning paper explores possibilities for STEAM (science, technology, engineering, arts, and mathematics) education with an education for sustainable development focus that counters disciplinary alienations particularly between the arts and the STEM (science, technology, engineering and mathematics) disciplines. The paper argues that unnecessary alienations between cultural-emblematic and mathematical-logical epistemes, especially those linked to narrow interpretations and restricted developments in dialogism and dialectics, respectively, are influenced by restricted understandings of epistemological, ontological, and praxiological philosophical drivers in meaning making and responsive action. In response, the paper develops a series of philosophical principles that, it argues, could usefully underpin STEAM education practices. These are a) iterations of epistemological expansion and contraction (in response to monologic meaning making), b) an expansive and deepening ontology (in response to ontological collapse in describing the world), c) critical and judgmental rationality (finding a middle ground between radical relativism and dogma), and d) concrete utopianism (in response to idealism and additive holisticism). The emergence of the four philosophical principles is developed through illustrative examples of a broad range of arts (fine art, performance art, photography, film, poetry, prose, and music).

The low levels of interest by students in science, technology, engineering, and mathematics (STEM)-related subjects and work is a challenge that needs to be resolved. And research has shown that arts-based, participatory, and humanistic methodologies-when integrated with the teaching of STEM subjects-have the potential to stimulate student interest, facilitate epistemological access, and hence, improve performance. Thus, in this self-study research paper, two science teacher educators share and reflect on their observations and experiences of using an arts-based teaching methodology (drama) in teaching science concepts and socio-scientific issues to pre-service teachers training to be high school teachers. Drama activities were used to teach the concepts of diffusion, DNA structure, meiosis, and a socio-scientific issue associated with albinism in African communities. Data were collected through the development of drama scripts, journaling observations, reflections, and discussions with a critical friend. Insights from the study show that the integration of drama into the science classroom creates opportunities for social interaction, for recognising students' active participation in their own learning, for power sharing, and for promoting engagement (cognitive, affective, and physical) that leads to the construction of new knowledge. In addition, drama pedagogy humanises science subject matter by showing its relevance and catering for varied learning styles. And drama ignites enthusiasm in students by invoking their innate sense of wonder. Consequently, adopting a STEAM (science, technology, engineering, arts, and mathematics) approach to teaching STEM subjects enriches epistemological access to scientific disciplines because such unconventional pedagogical strategies humanise abstract concepts, thereby increasing the likelihood of student success in these fields. There is, however, a need for heightened alertness in the teacher in order to pick up any misunderstandings and misconceptions about the science concepts that may manifest in the drama presentations.

Even with well-prepared lectures, some of my students still struggled to understand some of the concepts of cell biology. I therefore wondered if an exploration of teaching methods involving the arts would help them to engage with the subject content in ways that made it more accessible, and help them to understand the concepts better. Building on earlier approaches of using collaborative learning, I requested students to discuss, plan, and present to each other on cell biology concepts using arts-based teaching methods. In groups of 4-6 members, they could use any strategy such as dance, drama, music, poetry, and drawing to teach the concepts. The students collaboratively prepared content for a concept of their choice and presented it using their chosen and developed teaching strategy. Some of the strategies that students seemed to enjoy using included rapping the concepts, songs, dance, role play, and poetry. A few students resorted to individual PowerPoint presentations. The hope was that the enjoyment would translate into students' familiarisation with and understanding of the concepts better than through traditional teaching. Although the approach demonstrated that students could teach these concepts in versatile and fun ways, it did not assess their understanding of the concepts presented.

This work on STEAM and education for sustainable development was undertaken across a series of collaborative case studies as formative research on the inclusion of Indigenous technologies and knowledge practices in teacher education. We noted that, despite the current academic imperative to decolonise southern African education, one seldom finds the inclusion of Indigenous technologies and Indigenous heritage practices in the contemporary classroom. Teachers we worked with were highly interested in their Indigenous knowledge heritage. Yet, they reported that they, and the young teachers they work with, simply do not have the heritage knowledge capital to include Indigenous knowledge systems in their teaching. Other challenges they face are the time it takes to engage community knowledge holders, and to find knowledge relating to school subject disciplines. The teachers observed that students prioritise modernity over Indigenous heritage and technologies, often undervaluing the latter as a forgotten past. Three exploratory cases delved into teacher education's response to challenges through co-engaged work, and this paper synthesises the emerging evidence-aiming to refine pedagogical tools for integrating Indigenous knowledge into STEAM education. A cultural-historical approach was used to frame the study and to derive insights and inferences in co-engaged lesson design research with teachers.

This study explored the design principles of science, technology, engineering, arts, and mathematics (STEAM) learning activities developed by science and technology teachers for classroom practice. Through a qualitative approach, interpretive paradigm, and design-based research, 12 Bachelor of Education honours degree students were conveniently sampled. Data were collected by means of reflections and development of learning materials through the analysis, design, development, implementation, and evaluation (ADDIE) model. The study followed the design-based research stages of needs analysis, development, testing, and reflection to produce design principles, and it was underpinned by the learning theory of constructionism. The findings showcase the design principles to include design thinking, finding solutions for learning problems, creativity, and innovation applied to instructional design. The study recommends the use of design thinking pedagogies in developing teacher knowledge on STEAM classroom practice.

RESUMEN Los concentradores solares lineales son una tecnología prometedora para la generación de energía térmica en el sector industrial. Estos sistemas pueden generar agua caliente o vapor, con temperaturas dentro de un amplio rango en función del proceso o demanda. En este trabajo se presenta el diseño, construcción, montaje y ensayo experimental de un concentrador Fresnel lineal de 1.44 m2 de superficie de espejos. El equipo fue capaz de elevar la temperatura del agua a valores superiores a los 70 ºC, para caudales inferiores a 1 l/min, desarrollando una potencia térmica de 2000 W. A su vez, el equipo ensayado desarrolló potencias superiores a los 5000 W para caudales elevados. Los resultados indican que los concentradores solares lineales son una tecnología viable para la generación de energía térmica en el sector industrial, y que la normalización o modularización en función de la capacidad de producción (l/m2dia) permite proponer a esta tecnología como alternativa a los sistemas de calentamiento pasivo (calefones) disponibles en el mercado.

ABSTRACT Linear solar concentrators are a promising technology for thermal energy generation in the industrial field. These systems can generate hot water or steam, with temperatures within a wide range depending on the process or demand. This work shows the design, construction, assembly, and experimental testing of a linear Fresnel concentrator with a collecting area of 1.44 m2. The device was able to raise the temperature of water to values above 70 °C for flow rates below 1 l/min, developing a thermal power of 2000 W. Additionally, the concentrator developed thermal power output above 5000 W for higher flow rates. The results indicate that linear solar concentrators are a viable technology for the generation of thermal energy in the industrial field, and that standardization based on production capacity (l/m2day) allows this technology to be proposed as an alternative to passive heating systems (water heaters) available on the market.

Resumen: El nitrógeno en el suelo es crucial para la agricultura, pero a menudo es limitante, afectando el rendimiento de los cultivos. La deficiencia requiere fertilizantes sintéticos, pero su uso inadecuado causa daños ambientales y costos elevados. Las bacterias del género Rhizobium, simbiontes de leguminosas, ofrecen una solución al fijar nitrógeno de manera sostenible, reduciendo la dependencia de fertilizantes. Esta investigación determinó el número más probable (NMP) de células de Rhizobium spp. procedente de dos biofertilizantes comerciales de origen ecuatoriano y mexicano en condiciones de invernadero. Para esto, se realizó la inoculación directa con disoluciones seriadas (10-1 a 10-10) en macetas con pomina esterilizada al vapor, donde se germinaron plantas de frijol ejotero (Phaseolus vulgaris L.) de la variedad Blue Lake. A los 45 días después de siembra (DDS) se evaluaron los siguientes indicadores morfológicos: área foliar, peso de la planta en húmedo, altura de planta y número de flores, determinándose diferencias estadísticas entre el tipo de biofertilizante y la concentración de cada dilución. El experimento se adecuó a un diseño de bloques completos al azar con arreglo de parcela dividida con tres repeticiones por dilución, en consideración de las fluctuaciones de temperatura presentes en la zona de estudio. El NMP, al 95% de confianza, fue de 4,45x107 rizobios g-1 de pomina en una dilución 10-5 para el biofertilizante mexicano, y 1,48x105 rizobios g-1 de pomina en una dilución 10-4 para el biofertilizante ecuatoriano. La dilución óptima estimada para ambos productos fue de 10-8.

Abstract: Soil nitrogen is crucial for agriculture, but it is often limited, affecting crop yields. Deficiency requires synthetic fertilizers, but their improper use results in environmental damage and high costs. Bacteria of the genus Rhizobium, symbionts of legumes, offer a sustainable solution by fixing nitrogen, thus reducing dependence on fertilizers. This research determined the most probable number (MPN) of cells of Rhizobium spp. from two commercial biofertilizers of Ecuadorian and Mexican origin under greenhouse conditions. For this, direct inoculation with serial dilutions (10-1 to 10-10) was performed in pots with steam-sterilized pumice where Blue Lake variety snap bean (Phaseolus vulgaris L.) plants were germinated. The following morphological indicators were evaluated at 45 days after sowing (DAS): leaf area, plant wet weight, plant height, and number of flowers, determining statistical differences between the type of biofertilizer and the concentration of each dilution. The experiment followed a randomized complete block design with a split-plot arrangement, with three replicates per dilution, considering temperature fluctuations in the study area. The MPN at 95% confidence was 4.45x107 rhizobia g-1 of pumice at a 10-5 dilution for the Mexican biofertilizer, and 1.48x105 rhizobia g-1 of pumice at a 10-4 dilution for the Ecuadorian biofertilizer. The estimated optimal dilution for both products was 10-8.

Abstract Nowadays, there is growing pressure from society, governmental organisations and farmers to find sustainable weed management solutions that reduce or even eliminate the use of herbicides. We evaluated the efficacy and viability of alternative methods for weed management in a pear orchard (Pyrus communis). We compared the use of light-reflecting and non-reflecting tarps, thermal weeding using steam with and without prior weed mowing to the chemical control with flazasulfuron and a mixture of glyphosate + diflufenican + MCPA in autumn followed by glyphosate in the end of spring, and control (untreated). The assay was setup in the end of November 2019. An analysis of the economic viability of the treatments on the quantity and quality of the fruit was made. The tarps had an average efficacy of over 90 %, but they entail a high initial investment. The highest yields were obtained with tarps, followed by flazasulfuron and the thermal method with mowing. Flazasulfuron had an average efficiency of 75%, and 100% for the weedy species of the genus Equisetum. The costs of this method were quite high compared to the mixture of other herbicides, which had an average efficacy of only 56%. The efficacy of thermal weeding with and without prior mowing was 45% and 57% respectively. At the time of the trial, the high water consumption and low working speed were the negative aspects of this method.The integration of thermal weeding with other control methods should be the object of future research.

Resumo Atualmente, assiste-se a uma pressão crescente da sociedade, organismos estatais e agricultores na procura de soluções sustentáveis de gestão de infestantes que permitam a redução, ou mesmo a eliminação, do uso de herbicidas. Neste trabalho avaliou-se a eficácia e viabilidade de estratégias alternativas de gestão de infestantes num pomar de pereiras (Pyrus communis), designadamente telas refletoras e não refletoras de luz, monda térmica com vapor de água com e sem corte prévio de infestantes, em comparação com o uso de flazassulfurão e mistura de glifosato+diflufenicão+MCPA no outono seguida de glifosato no final da primavera, e controlo (testemunha não tratada). O ensaio foi instalado no final de novembro de 2019. Realizou-se uma análise da viabilidade económica dos tratamentos e dos efeitos na produtividade, nomeadamente na quantidade e qualidade da fruta. As telas tiveram eficácias médias globais acima de 90%, no entanto o custo da sua instalação e aquisição é bastante elevado. Nas modalidades com telas obtiveram-se maiores produções, seguidas do flazassulfurão e monda térmica com corte. O flazassulfurão teve uma eficácia média global de 75% e 100% para infestantes do género Equisetum. Os custos desta modalidade são bastante elevados comparativamente à modalidade com mistura de herbicidas, que teve eficácia média de apenas 56%. A eficácia da monda térmica com e sem corte das infestantes foi de 45% e 57%, respetivamente. À data do ensaio, o elevado gasto de água e a baixa velocidade de trabalho foram os aspetos negativos deste método. A integração da monda térmica com outros métodos deve ser objeto de futura investigação.

Abstract The genus Psidium, belonging to the family Myrtaceae, encompasses several plant species rich in essential oils. Several studies involving different research areas have shown promising results for essential oils, which has attracted interest from diverse sectors, including pharmaceutical, food, and cosmetic industries. Thus, the objective of this study was to evaluate the biological activity of the essential oil extracted from Psidium bahianum leaves (EOPb) collected in an Atlantic Forest remnant in the northern coast of the state of Bahia, Brazil. EOPb was extracted by steam distillation and analyzed through proton nuclear magnetic resonance (1H-NMR). The free radical scavenging activity was assessed using the DPPH methodology (analyzing the scavenging of the stable free radical 1,1-diphenyl-2-picrylhydrazyl). Antimicrobial disk diffusion assays were conducted; toxicity was determined through assays on sheep erythrocytes and Artemia salina. 1H-NMR evaluation showed the presence mainly of monoterpenes and sesquisterpenes. The percentage of antioxidant activity was 18.03±2.53 53 for 125 125 µg mL-1. Antimicrobial assays showed that the essential oil at a concentration of 10 mg mL-1 inhibited the growth of the microorganisms Staphylococcus aureus, Bacillus subtilis, B. cereus, Micrococcus luteus, Escherichia coli, Aspergillus niger, Candida albicans, and C. glabrata. The toxicity results indicated that concentrations of EOPb at 10, 100, 250, and 500 µg mL-1 were not toxic to sheep erythrocytes. The toxicity assay on A. salina showed that the lethal concentration for 50% of individuals (LC50) within 24 and 48 hours were 371.48 and 302 µg mL-1 of EOPb, respectively, which were considered moderately toxic, whereas the LC50 within 72 horas was 33.11 µg mL-1, considered highly toxic. These findings are promising, as the essential oil from P. bahianum leaves showed antimicrobial activity against both Gram-positive and Gram-negative bacteria and fungi. The data obtained for the essential oil toxicity in A. salina could be tested on different tumor cell lines. Myrtaceae oils sectors pharmaceutical food industries Thus (EOPb Bahia Brazil 1HNMR. 1HNMR HNMR 1H NMR . H (1H-NMR) analyzing 1,1diphenyl2picrylhydrazyl. 11diphenyl2picrylhydrazyl diphenylpicrylhydrazyl 1,1 diphenyl 2 picrylhydrazyl 1 1,1-diphenyl-2-picrylhydrazyl) conducted sesquisterpenes 1803253 18 03 18.03±2.5 5 12 mL1. mL1 mL 1. mL- aureus subtilis B cereus luteus coli niger albicans C glabrata 100 250 50 A LC (LC50 4 37148 371 371.4 30 respectively LC5 7 3311 33 11 33.1 mL1, 1, P Grampositive Gram positive Gramnegative negative fungi lines (1H-NMR 1diphenyl2picrylhydrazyl 1,1diphenyl2picrylhydrazyl 1,1-diphenyl-2-picrylhydrazyl 180325 0 18.03±2. 25 (LC5 3714 37 371. 3 331 33. 18032 18.03±2 (LC 1803 18.03± 180 18.03 18.0 18.

Resumo O gênero Psidium, pertencente à família Myrtaceae é rico em óleos essenciais que vêm sendo utilizados na indústria farmacêutica, alimentícia e na estética. Desse modo, o objetivo geral deste estudo foi avaliar a atividade biológica do óleo essencial de Psidium bahianum coletadas em remanescente de Mata Atlântica no Litoral Norte da Bahia, Brasil. O óleo essencial (OEPb) foi obtido das folhas do P. bahianum por arraste a vapor d'água. O OEPb foi analisado pela Ressonância magnética nuclear de H1. A atividade sequestradora de radicais livres foi avaliada pela metodologia de DPPH (analisando a eliminação do radical livre estável 1,1-difenil-2-picrilhidrazil). Foram realizados testes antimicrobianos em difusão em disco, e para a determinação da atividade tóxica realizou-se através dos ensaios em hemácias de carneiro e Artemia salina. O estudo de ressonância demonstrou principalmente a presença de monoterpenos, dentre eles o linalol, e sequisterpenos. A porcentagem da atividade antioxidante foi de 18,03 ± 2,53 53 para 125 µg /mL. No ensaio antimicrobiano o óleo essencial inibiu o crescimento dos microrganismos Staphylococcus aureus, Bacillus subtilis, Bacillus cereus, Micrococcus luteus, Escherichia coli, Aspergillus niger, Candida albicans e Candida glabrata testados na concentração de 10mg/mL. Os resultados da toxicidade demonstraram que nas concentrações de 10 e 100, 250 e 500µg/mL, o óleo essencial não é tóxico para hemácias de carneiro. No teste de toxicidade em Artemia salina, os resultados mostram que em 24 e 48 horas da DL50 é de 371,48 e 302µg/mL de óleo essencial sendo considerados moderadamente tóxicos e em 72 horas a DL 50 é de 33,11µg/mL considerado altamente tóxico. Os dados alcançados são promissores, uma vez que o óleo essencial de P. bahianum demostrou atividade antimicrobiana para bactérias Gram positiva e negativa e para fungos. Os dados obtidos de toxicidade em A. salina para o óleo essencial poderá ser testado em diferentes linhagens tumorais. farmacêutica estética modo Bahia Brasil (OEPb P dágua. dágua d água. água d'água H1 H analisando 1,1difenil2picrilhidrazil. 11difenil2picrilhidrazil difenilpicrilhidrazil 1,1 difenil 2 picrilhidrazil . 1 1,1-difenil-2-picrilhidrazil) disco realizouse realizou se monoterpenos linalol sequisterpenos 1803 18 03 18,0 253 2,5 5 12 mL /mL aureus subtilis cereus luteus coli niger 10mgmL mgmL 10mg mg 10mg/mL 100 25 500µgmL µgmL 500µg 500µg/mL 4 DL5 37148 371 371,4 302µgmL 302µg 7 3311µgmL 33 11µg promissores fungos tumorais 1difenil2picrilhidrazil 1,1difenil2picrilhidrazil 11 1, 1,1-difenil-2-picrilhidrazil 180 0 18, 2, 3714 37 371, 3