Abstract Objective: to describe the characteristics of work-related COVID-19 cases reported in Brazil between 2020 and 2021. Methods: descriptive study using secondary data collected from the Brazilian Notifiable Diseases Information System (SINAN). Frequency was calculated according to sociodemographic, occupational and epidemiological variables. Results: in the years 2020 and 2021, a total of 36,110 and 34,508 work-related COVID-19 cases were reported, respectively. Considering both years, there was a higher frequency of notifications for female individuals (65.1%), black and mixed-race (42.1%), from the age group 30 to 39 years (32.8%). The Northeast region accounted for 28.4% of the reported cases. Work Accident Report (CAT) was issued in 13.5% of the reported cases, with a high percentage of missing information for this variable (42.6%). Middle-level technicians (31.0%) and professionals in sciences and the arts (23.7%) accounted for most notifications. Cure was the most prevalent outcome in both years (2020: 72.0%; 2021: 68.0%). Conclusion: the results point to a predominant profile of cases among women, black and mixed-race individuals, and those aged between 30 and 39 years. The low completeness of notifications is noteworthy.

Resumo Objetivo: descrever as características dos casos de COVID-19 relacionados ao trabalho notificados no Brasil, em 2020 e 2021. Métodos: estudo descritivo com dados do Sistema de Informação de Agravos de Notificação (Sinan). Foram calculadas as frequências de casos segundo variáveis sociodemográficas, ocupacionais e epidemiológicas. Resultados: nos anos de 2020 e 2021, foram notificados 36.110 e 34.508 casos de COVID-19 relacionados ao trabalho, respectivamente. Considerando os dois anos, houve maior frequência de notificações de casos de indivíduos do sexo feminino (65,1%), de raça/cor da pele preta e parda (42,1%) e na faixa etária de 30 a 39 anos (32,8%). A região Nordeste concentrou 28,4% dos casos notificados. Houve emissão de comunicação de acidente de trabalho (CAT) em 13,5% dos casos notificados, com elevada proporção de informação ausente para essa variável (42,6%). As categorias ocupacionais com mais notificações foram técnicos de nível médio (31,0%) e profissionais de ciências e artes (23,7%). A evolução cura foi a mais frequente nos dois anos analisados (2020: 72,0%; 2021: 68,0%). Conclusão: os resultados apontam para um perfil de casos com predominância de mulheres, trabalhadores(as) de raça/cor da pele preta e parda e com idades entre 30 e 39 anos. Destaca-se, ainda, a baixa completude das notificações.

The United Nations Educational, Scientific, and Cultural Organization (UNESCO) highlights the relevance of using information and communications technology (ICT) in education for improving the quality of education. To achieve this goal, it is necessary to extend research on digital competences in education. To advance the development of digital competencies it is necessary to take account of how teachers perceive these. In addition, systematic reviews of the literature on ICT and education show an imbalance regarding the amount of research from Africa compared to other regions of the world. In this sense, the objective of this study carried out between March 2019 and April 2020 was to analyse the perceptions of primary school teachers from 8 African countries about their digital competences. The teachers were master's students in teacher training on virtual platforms. A mixed methodological perspective (quantitative-qualitative) was adopted and a questionnaire with closed and open-ended questions was applied. The quantitative and qualitative analyses show that the teachers recognised their digital competence at all 3 levels. The needs highlighted by teachers were in developing their knowledge of how to create content with the support of technology. However, the available resources, which differed in the participants' work contexts and did not enable the equal use of ICT in all African countries, was an important issue highlighted by the participants. It is recommended that teacher training in digital competence is prepared using instructional design that promotes innovation and contact with real teaching-learning situations.

La vinaza generada en el proceso de producción de bioetanol en Tucumán se dispone principalmente en campos, por lo que el costo de transporte y almacenamiento se ve sensiblemente impactado por la disminución del volumen de ese subproducto mediante la concentración. Utilizando una planta piloto con evaporador de películas descendente, se trabajó simulando individualmente cada etapa de un sistema de quíntuple efecto. Los experimentos fueron diseñados de manera que los resultados permitieran evaluar la factibilidad del proceso de concentración de vinaza y las principales variables a controlar, a los fines de simular un sistema de evaporación de múltiple efecto y determinar los coeficientes globales de transferencia de calor. Los ensayos se completaron satisfactoriamente, aumentando la concentración total de la vinaza de 10º Bx hasta 35º Bx. La viscosidad no presentó problemas en los intervalos de concentración estudiados, siguiendo su valor un comportamiento polinómico según el efecto,de la forma ¼  = 0,145 (ef)³ - 0,8823 (ef)² + 1,3855 (ef) + 1,9219 [cP]. Se estableció un conjunto de condiciones térmicas para un sistema de cinco efectos, con un intervalo global de temperatura de evaporación que va desde los 105ºC para el primer efecto y de 60ºC para el último efecto, que posibilitan concentrar vinaza hasta 35º Bx. Para un importante conjunto de componentes químicos de la vinaza, se muestra la evolución en sus concentraciones de acuerdo al Bx y a la etapa del sistema de evaporación Así, para el caso del potasio, este toma la forma: 1,9118 (ef) + 129,98 [gr/L/ºbx]; mientras para el calcio: -1,22 (ef) + 21,8 [gr/L/ºbx]. El coeficiente global de transferencia de calor varía en función del efecto, dando un comportamiento cuadrático: - 27,497(ef)² - 147,91(ef) + 2499 [W/ºC/m² ].

In Tucumán, the vinasse generated in the production of bioethanol is used mainly in the fields, so the cost of transportation and storage is significantly affected by the decrease in its volume through its concentration. Using a pilot plant falling film evaporator, each stage of a quintuple system was simulated individually. The tests were designed in such a way that the results made it possible to evaluate the viability of the stillage concentration process and the main variables to control. The tests were successfully completed as stipulated, increasing the total stillage concentration from approximately 10 ° Bx to approximately 35 ° Bx. Viscosity does not present any problem in the concentration ranges studied, its value follows a polynomial behavior according to the effect; ¼  = 0.145 (ef)³ - 0.8823 (ef)² + 1.3855 (ef) + 1.9219 [cP], where ef is the effect number. A set of thermal conditions was established for a multiple effects system, with an evaporation temperature of 105 ° C for the first effect and 60 ° C for the laser effect. The changes in the concentrations of a significant number of chemical components of the vinasse were determined by analyzing the brix in each evaporation stage and chemical group. In the case of potassium, the concentration is as follows: 1.9118 (ef) + 129.98 [g / L / ºBx]; while for calcium: -1.22 (ef) + 21.8 [g / L / ºBx]. the global heat transfer coefficient changes with the effect number, showing a quadratic form: - 27.497 (ef) 2 - 147.91 (ef) + 2499 [W / ºC / m² ] .

Abstract The primary objective of this research is to study the relationship between reaction time (RT) and movement time (MT) in a sample of 121 football referees. Assessment has been performed using an objective computerised test (RT, Vienna Test System©), with regard to the average score obtained for refereeing performance over the season (RAR in Spanish). To perform the analysis, the following variables have been considered: a) Level refereed (2 levels); b) Age (3 levels); and c) Experience (4 levels). The hypothesis states that: (i) The higher the level refereeing at, better results are expected in RT and MT; (ii) The older the referee, the greater the expected value in RT and MT; (iii) The more experienced the referee, the lower the score expected in RT and MT; and (iv) It is expected that there will be a negative correlation between the RAR and the RT and MT scores. The results show that: (i) RT and MT do not differentiate between semi-professionals and amateur referees; (ii) Only the older group has differences in line with the proposed hypothesis; (iii) There are no differences in RT and MT regarding refereeing experience; (iv) The RT scores, taking the optimal transformation parameters, show significant correlations with the RAR (r = -.271, p = .020); but not regarding the MT and RAR. Future research should take a deeper look into the results obtained, including professional referees in the comparisons, as well as investigating the effects of other psychological variables in refereeing performance.

Resumen El objetivo prioritario de esta investigación se centra en estudiar, en una muestra de 121 árbitros de fútbol, la relación que existe entre su tiempo de reacción (TR) y de movimiento (TM) -evaluado mediante la realización de una prueba objetiva computerizada (RT, Vienna Test System©)-, respecto a la puntuación promedio obtenida durante la temporada sobre su rendimiento arbitral real (RAR). Para realizar los análisis se han considerado las siguientes variables: (a) Categoría arbitral (2 niveles); (b) Edad (3 niveles); y (c) Experiencia (4 niveles). Las hipótesis establecen que: (i) A mayor categoría arbitral, se esperan mejores resultados en TR y TM; (ii) A mayor edad, se esperan obtener mayores valores en TR y TM; (iii) A mayor experiencia, se esperan menores puntuaciones en TR y TM; y (iv) Se espera que exista correlación negativa entre RAR, con sus puntuaciones en RT y en TM. Los resultados muestran que: (i) TR y el TM no permiten discriminar entre los árbitros semi-profesionales y los amateurs; (ii) Sólo el grupo de más edad tiene diferencias en la línea de la hipótesis planteada; (iii) No se producen diferencias en RT y TM en función de las experiencias arbitrales; y (iv) Las puntuaciones en RT, tomando el parámetro óptimo de transformación, muestran correlaciones significativas con RAR (r = -.271, p = .020); no así respecto a TM y RAR. Futuras investigaciones deben profundizar en los resultados obtenidos, añadiendo en las comparaciones a los árbitros profesionales, además de explorar el efecto de otras variables psicológicas en el rendimiento arbitral.

We report the first record of the Stygian Owl (Asio stygius) for the state of Queretaro. The observation corresponds to an individual that was shot and seized in the Landa de Matamoros municipality, in the Sierra Gorda Biosphere Reserve. This record reinforces the hypothesis of an extended distribution of A. stygius throughout the northern part of the Sierra Madre Oriental.

Reportamos el primer registro del búho cara oscura (Asio stygius) para el estado de Querétaro. El registro corresponde a un individuo que fue herido y decomisado en el municipio de Landa de Matamoros, en el interior de la Reserva de la Biosfera Sierra Gorda. Esta observación refuerza la hipótesis de una distribución extendida de A. stygius a través de la parte septentrional de la Sierra Madre Oriental.

Magnolia rzedowskiana A. Vázquez, R. Domínguez & R. Pedraza is described as a new species of the sect. Macrophylla. It is found in Sierra Gorda, Querétaro, Sierra de Xilitla, San Luis Potosí, and vicinity of Chapulhuacán, Hidalgo, México, in cloud forests. It shares with other members of sect. Macrophylla its deciduous and abaxially glaucous leaves. It is similar to Magnolia dealbata in having similar size of trees and leaves, but differs from the latter in having narrower petals, less numerous stamens, styles flattened, acute at the apex and white yellowish to dark maroon (vs. cylindrical and truncate to rounded at the apex and creamy white), smaller fruits, less numerous carpels, and carpels with shorter beak.

Se describe Magnolia rzedowskiana A. Vázquez, R. Domínguez & R. Pedraza, un taxon nuevo perteneciente a la sección Macrophylla. Se distribuye en la Sierra Gorda, Querétaro, Sierra de Xilitla, San Luis Potosí, y los alrededores de Chapulhuacán, Hidalgo, México, en bosque mesófilo de montaña. Se asemeja a otras especies de la sección Macrophylla en sus hojas deciduas con envés glauco; comparte con Magnolia dealbata el tamaño de árbol y de hojas, pero difiere de esta última por sus pétalos mucho más angostos, menor número de estambres, estilos aplanados, de ápice agudo y color blanco-amarillento a marrón oscuro (vs. cilíndricos, de ápice truncado-redondeado y color blanco crema), menor tamaño de frutos, menor número de carpelos y éstos con el pico más corto.

Establecer el origen de los principios que sirven de contenido a la norma básica, resulta de especial relevancia a fin de poder determinar el papel que estos cumplen en el sistema social. De allí que resulte de interés y necesidad epistemológica abordar tal como se hace en este artículo de reflexión producto de los resultados de la investigación denominada: "El contenido de la norma fundamental desde el paradigma interpretativo", que se desarrolló en el marco de la línea de investigación de asuntos Constitucionales y administrativos del Grupo de Investigaciones en Derecho, Política y Sociedad, financiado por la Facultad de Derecho de la Universidad de la Costa. El problema del origen de los principios que constituyen el contenido de la Norma Básica Fundamental. Es que el contenido del Derecho se puede constituir de la norma que sirve de fundamento al sistema jurídico que debe basarse en principios que no tengan un origen único y exclusivo, sino que se apoyen o consideren todas las disciplinas o sistemas que conforman la sociedad. El estudio se enfocó desde dos paradigmas fundamentales que pueden servir de modelo desde la postmodernidad social actual, como son: 1) El discursivo racional comunicacional y, 2) El que podríamos denominar de la teoría del caos fundamentado en el desequilibrio, tensión y crisis de los sistemas sociales. Para tal fin, se empleó una metodología jurídica con un enfoque cualitativo, en aplicación de la llamada Teoría Fundamentada de Strauss y Corbin, que nos permite la construcción de una teoría a partir de la recopilación, análisis e investigación de datos cualitativos, relacionados con el núcleo.

In order to determine the role of the principles in the social system, it is necessary to set the origin of these principles. Moreover, it is important to address the epistemological needs addressing in this article. This is the results of a research entitled: "The content of the fundamental rule from the interpretive paradigm" that was developed in the framework of the research on Constitutional and administrative law by the research group of the Law faculty. The problem of the origin of the principles that form the content of the Basic Fundamental is that its content of the law relies on the legal system. However, this system must be based on principles that do not have a unique and exclusive origin, considering all disciplines and systems that make up society. The study focuses on two fundamental paradigms that can serve as a model from the current social postmodernism, such as: 1) rational discourse and communication; 2) this could be called the chaos theory based on the imbalance, stress and crisis social systems. To this end, a legal methodology was used with a qualitative approach, applying the so-called Grounded Theory by Strauss and Corbin, which allows us to build a theory from the collection, analysis and investigation of qualitative data related core.

En este estudio se evaluó el método SODIS y SODIS combinado con Artemisia annua como una alternativa para la desinfección del agua en comunidades sin acceso a agua segura. Se determinó la eficiencia del método en la remoción de Escherichia coli, Bacillus subtilis, Enterococcus faecalis y Salmonella typhimurium usando botellas tipo PET con agua destilada estéril y una concentración inicial de 1x10(6) UFC/ml de cada microorganismo. Para la combinación SODIS-A. annua se adicionó a las botellas una infusión de A. annua al 10% (v/v); las botellas fueron expuestas al sol durante mínimo 6 horas y se determinaron las variables temperatura del agua, radiación solar y turbidez. Se encontró que el tratamiento SODIS fue más eficiente en la remoción de los cuatro microorganismos que el tratamiento SODIS + A. annua. Las remociones más altas se encontraron a partir de las cuatro horas de exposición para las especies bacterianas en estado vegetativo.

This study evaluates the SODIS and SODIS method combined with Artemisia annua (SODIS+A. annua) as an alternative for water disinfection in communities without access to potable water. The efficiency of the method in removing E. coli, B. subtilis, E. faecalis and S. typhimurium was determined using PET bottles with sterile distilled water and an initial concentration of 1x10(6) UFC/ml of each microorganism. For SODIS+A. annua a 10% (v/v) infusion of A. annua was added; the bottles were exposed to sunlight for at least 6 hours and three variables (water temperature, solar radiation and turbidity) were measured. It was found that SODIS treatment was more efficient in the removal of the four microorganisms than SODIS + A. annua. The removals were higher after four hours of exposure to the bacterial species in their vegetative state.

Objetivo analisar a histologia cardíaca, a pressão arterial (PA), a frequência cardíaca (FC) e a variabilidade da frequência cardíaca (VFC) de ratos submetidos a treinamento físico e suplementação de cafeína. Métodos sessenta ratos foram divididos em grupos controle (CO), controle suplementado com cafeína (CAF), treinados controle (TRE) e treinados suplementados com cafeína (TCAF). Os grupos de treinamento realizaram natação por quatro semanas, e os grupos de cafeína foram suplementados por ingestão voluntária de cafeína diluída em água. Resultados não houve modificações para PA e FC entre os grupos. Em relação à VFC, houve diminuição nos componentes LFnorm (baixa frequência) e LF/HF (razão baixa e alta frequência) em TCAF em relação a CAF (p<0,02 e p<0,03, respectivamente). Houve também aumento em CAF em relação a CO no componente LFnorm (p<0,05). Os resultados também mostraram aumento no peso relativo do coração em TRE (p<0,04) e TCAF (p<0,03) em relação a CO. Conclusão a cafeína não modificou as respostas hemodinâmicas. Entretanto, a natação diminuiu a resposta simpática e aumentou o peso relativo do coração.

Objective to analyze the morphological structure of cardiac, blood pressure (BP), heart rate (HR) and heart rate variability (HRV) of rats subjected to physical training with supplementation of caffeine. Methods 60 rats were divided into 4 groups: control (CO), control with caffeine (CAF), trained control (TRE) and trained with caffeine (TCAF). All trained groups underwent 4 weeks of swimming, and all caffeine groups were supplemented by voluntary ingestion of caffeine diluted in drinking water. Results there were no changes to BP and HR between groups. Regarding HRV, there was a decrease in LFnorm (low frequency) and LF/HF ratio (low and high frequency) in TCAF and CAF compared to group (p<0.02 and p<0.03, respectively). An increase occurred in CAF compared to the CO in the component LFnorm (p<0.05). The results also showed an increase in the relative weight of heart in the TRE (p<0.04) and TCAF (p<0.03) compared to CO. Conclusion caffeine did not modify the hemodynamic responses. However, physical training resulted in a decrease in sympathetic response and an increase in relative heart weight.

Se presenta el diseño conceptual de una planta experimental de tratamiento de aguas residuales para poblaciones menores de 30.000 habitantes. El diseño integra seis esquemas de tratamiento interconectados, incluyendo sistemas convencionales y no convencionales, con disposición final del efluente a un cuerpo de agua o infiltración lenta en el terreno, cumpliendo con la norma vigente en Colombia. El proceso incluyó una revisión del estado del arte, el diseño de plantas de este tipo como la planta de Carrión de los Céspedes (Andalucía-España), la planta UFMG/COPASA (Minas Gerais-Brasil), los trabajos realizados en Colombia del IDEAM-CINARA-UTP y los ensayos realizados por Madera, Silva y Peña del CINARA en planta piloto. El área estimada para la construcción de los esquemas propuestos es de 18.000 m² y los costos fijos de construcción de la planta se estiman en 850 millones de pesos para tratar un caudal de 1,5 l/s de agua residual doméstica.

Conceptual design of an experimental waste water treatment plant for populations lower than 30,000 inhabitants is presented. The design integrates six interconnected treatment systems, including conventional and non-conventional systems with final disposal of the effluent to a water body or slow infiltration in the soil, complying with Colombian norms in force. The process included a state-of-the-art revision, design of this kind of plants (such as Carrión de los Céspedes in Andalucía, Spain; UFMG/COPASA plant in Minas Gerais-Brazil), works conducted in Colombia (IDEAM-CINARA-UTP), and tests performed by Madera, Silva, and Peña from CINARA in a pilot plant. Area estimated for construction of systems proposed reaches 18,000 m² and fixed costs for construction of the plant is estimated in 850 million Colombian pesos for treating a 1.5 l/s flow of household waste water.

Foram avaliados os efeitos da ingestão crônica de cafeína e exercício de natação sobre o tecido ósseo. Ratos Wistar jovens (n = 32) alocados em quatro grupos: sedentário controle (SCO), sedentário + cafeína (SCAF), treinados (TCO) e treinados + cafeína (TCAF), receberam 1 mg/ml de cafeína em água durante 30 dias (SCAF e TCAF) e foram submetidos a 21 dias de natação em intensidade moderada (TCO e TCAF). A tíbia esquerda foi submetida a ensaio biomecânico para determinação do coeficiente de rigidez, limite de elasticidade e carga máxima. A área de tecido ósseo primário e espessura do disco epifisário foram avaliadas no fêmur. Não foram observadas alterações nas propriedades biomecânicas e na deposição de tecido ósseo primário. O grupo SCAF apresentou maior espessura no disco epifisário distal. Os resultados sugerem que o treinamento moderado de natação e a ingestão de cafeína não provocaram alterações morfológicas e biomecânicas do tecido ósseo.

Effects of swimming training and chronic caffeine intake on bone tissue of young rats were investigated. Young Wistar rats were allocated into 4 groups: sedentary control (SCO), sedentary + caffeine (SCAF), trained (TCO) and trained + caffeine (TCAF); they received 1 mg/ml of caffeine diluted in water for 30 days (SCAF and TCAF) and were submitted to swimming training of moderate intensity for 21 days (TCO and TCAF). The left tibia was subjected to the biomechanical test for determination of the coefficient of stiffness, yield and maximum load. The immature bone tissue area and thickness of growth plates were evaluated in the femur. No changes were observed in biomechanical properties and the area occupied by immature bone tissue. However, SCAF group presented greater thickness in distal growth plate. The results suggest that the moderate intensity swimming training and caffeine consumption were not able to promote changes in morphology and biomechanical properties of bone tissue.

Se evaluaram los efectos del consumo crónico de cafeína y la natación em el hueso. Ratas Wistar jóvenes (n=32) divididas en cuatro grupos: sedentarios control (SCO), sedentarios + cafeína (SCAF), entrenados (TCO) y entrenados + cafeína (TCAF), recibieron 1 mg/ml de cafeína en agua durante 30 días (SCAF e TCAF) e fueron sometidos 21 días de la natación moderada. La tibia izquierda se sometió a una prueba biomecánica para determinar la coeficiente de la rigidez, el limite de elasticidad y el punto de carga máxima. El area de hueso imaturo e de la zona de la placa de crescimiento proximal e distal se analizó em el fêmur. No se observaron cambios en las propiedades biomecánicas y el déposition de hueso inmaturo. Animales SCAF tenía más grueso de la placa de crescimiento distal. Los resultados sugieren que entrenamento moderalado de la natación y el cosumo crônico de cafeína no cambió la morfología y las propiedades biomecánicas del hueso.

The present study poses the hypothesis that the perception of direct competition by a strategic business unit leader (SBU) depends on three variables: similarity of product offered, similarity of targeted market and similarity of strategic capabilities in the competing companies. It is proposed that the decision of who is the competition depends more on the managers' perception than on an objective rule. These three variables are initially detected through a qualitative study where SBU leaders were interviewed, which was later substantiated with a related literature search. The relation among these three variables and the perception of direct competition is corroborated through an empirical test where questionnaires were applied to SBU leaders as well, and served to measure the relation between such variables. The present study frameworks the notion of cognitive strategic groups starting from the idea that its members would tend to perceive each other as direct competitors, and that this perception of direct competition could be used as a factor to construe such groups. The results suggest that the perception of direct competition does depend on each of the three similarity variables. A statistical analysis of two kinds was undertaken, the first one based on correlations taking the direct competition perception as an ordinal variable. A second analysis used Chi-squared and contingency tables with a dichotomic dependent variable: the most direct competition versus the least direct competition.

En el presente trabajo se ofrece la hipótesis de que la percepción de competencia directa por parte de un líder de unidad estratégica de negocio (UEN) depende de tres variables: similitud del producto ofrecido, similitud del mercado atacado y similitud de capacidades estratégicas de las empresas competidoras. Se propone que la competencia directa depende más de la percepción de los gerentes que de una decisión basada en una regla objetiva. Estas tres variables son detectadas inicialmente en una revisión de literatura y son corroboradas mediante un estudio cualitativo donde se entrevistó a líderes de UEN. La relación entre estas tres variables y la percepción de competencia directa se corrobora mediante una prueba empírica donde se aplican cuestionarios -también a líderes de UEN- que sirvieron para medir la relación entre tales variables. El presente trabajo se enmarca en la noción de grupos estratégicos; se parte de que los integrantes de uno tenderían a percibirse como competidores directos y que esta percepción de competencia directa podría ser un factor para conformar tales grupos. Los resultados arrojan que la percepción de competencia directa sí es dependiente de cada una de las tres variables de similitud. Se hace un análisis estadístico de dos tipos: uno basado en correlaciones tomando la percepción de competencia directa como una variable ordinal y otro en chi-cuadrada y tablas de contingencia tomando la dependiente como una variable dicotómica: la de competencia más directa versus la de competencia menos directa.

The essential oils of citric fruits constitute complex mixtures of organic compounds which interfere with pesticide residues quantitation. As there exists scarce bibliography on ortho-phenylphenol (OPP) determination in this commodity, the present work aims to adapt, develop and validate a simple and cheaper method for determining phenylphenol residues in citrus essential oil, while certifying it under IRAM 301 standard (ISO/IEC 17025:2005). Citrus fruit analysis methods were used, taking advantage of OPP acidity for its extraction from the commodity by simple acid-base extraction. Later, gas chromatography with flame ionization detector (GC-FID) was used for detection and quantitation. Average recoveries were the following: 89% to 104% within the range of 0.1 mg/kg to 100 mg/kg for lemon essential oil; 93% to 103% and 90% to 114%, for white and red grapefruit, respectively, within the range of 0.2 -10 mg/kg. Detection limits were 0.05 mg/kg for lemon essential oil and 0.1 mg/kg for both white and red grapefruit essential oils. Quantitation limits were 0.1 and 0.2 mg/kg for lemon and grapefruit essential oils, respectively. Also, an acceptable linearity was observed in the evaluated ranges and relative uncertainties of 24%, 14% and 23% for lemon, white and red grapefruit essential oils, respectively, were obtained.

Los aceites esenciales de frutas cítricas constituyen mezclas complejas de compuestos orgánicos que interfieren en la cuantificación de residuos de plaguicidas. Siendo escasa la bibliografía encontrada para la determinación de orto-fenilfenol (OPP) en estas matrices, este trabajo apunta a adaptar, desarrollar, validar y acreditar bajo Norma IRAM 301 (ISO/IEC 17025:2005), un método sencillo y de menor costo. Para dicha cuantificación, se tomaron como punto de partida metodologías aplicadas al análisis de frutas cítricas y se aprovechó el carácter ácido del OPP para separarlo mediante una extracción ácido-base. Posteriormente, fue detectado y cuantificado por cromatografía gaseosa (CG) con detector de ionización de llama (FID). Se obtuvieron recuperaciones promedio de 89% a 104%, en el rango de 0,1 a 100 mg/kg, para aceite esencial de limón (AEL); de 93% a 103 % y de 90% a 114% entre 0,2 mg/kg y 10 mg/kg de OPP para aceite esencial de pomelo (AEP) blanco y rosado, respectivamente. Los límites de detección fueron 0,05 mg/kg para AEL y 0,1 mg/kg para AEP blanco y rosado. Los límites de cuantificación fueron 0,1 mg/kg para AEL y 0,2 mg/kg para AEP. Además, se observaron una linealidad aceptable en los rangos evaluados e incertidumbres relativas de 24% para AEL, 14% para AEP blanco y 23% para AEP rosado.

A volumetric material verification plan which can be easily followed and an example of its practical application to the assessment of volumetric flasks are reported. The procedure would guarantee the reliability of analysis results, while ensuring that laboratories meet the requirements established by IRAM 301:2005 (ISO/IEC 17025:2005) standard.

Se describe un plan de verificación de material volumétrico, y como ejemplo, un procedimiento para matraces aforados, de fácil realización, para garantizar la confiabilidad de los resultados de ensayos, asegurando además el cumplimiento con los requerimientos establecidos por el Instituto Argentino de Normalización y Certificación (IRAM) en su norma IRAM 301:2005 (ISO/IEC 17025:2005), aplicada a la acreditación de laboratorios de ensayos.

Near Infrared Spectroscopy (NIRS) is an instrumental method which has been increasingly developing during the last few years in sugar industry worldwide. It is employed at research centres and in various industries as well, due to its advantages: it is a non-destructive technique, it is fast and does not require chemical reagents or as much workforce as required by traditional methods used in the laboratory. This work aims to determine the most suitable calibration models to predict Brix and pol in sugarcane juice by means of NIRS equipment, so as to replace traditional methods based on those two parameters. Results obtained from statistical indicators like standard error of calibration (SEC), standard error of prediction (SEP) and calibration correlation coefficient (R²) were highly satisfactory for the evaluated parameters and showed agreement with values reported in existing bibliography.

La espectroscopia por infrarrojo cercano (NIRS) es una metodología instrumental que ha presentado un desarrollo creciente en los últimos años en la industria azucarera mundial. Se la utiliza tanto en centros de investigación como en diversas industrias, por ser una técnica no destructiva, rápida, que no emplea reactivos químicos y que requiere menos mano de obra que los métodos tradicionales empleados en el laboratorio. Por tal motivo, se decidió determinar para las condiciones de la industria azucarera de Tucumán (Argentina), los modelos de calibración más adecuados que permitan predecir los parámetros Brix y pol en jugo de caña de azúcar, mediante el empleo de un equipo NIRS, haciendo posible el reemplazo de los ensayos tradicionales de estos dos parámetros. Los resultados obtenidos de indicadores estadísticos, tales como error estándar de calibración (SEC), error estándar de predicción (SEP) y coeficiente de correlación de la calibración (R²) fueron altamente satisfactorios en los parámetros evaluados y presentaron concordancia con los valores encontrados en la bibliografía mundial.