ABSTRACT
The utilisation of Mg(OH)2 to capture exhaust CO2 has been hindered by the limited availability of brucite, the Mg(OH)2 mineral in natural deposits. Our previous study demonstrated that Mg(OH)2 can be obtained from dunite, an ultramafic rock composed of Mg silicate minerals, in highly concentrated NaOH aqueous systems. However, the large quantity of NaOH consumed was considered an obstacle for the implementation of the technology. In the present study, Mg(OH)2 was extracted from dunite reacted in solid systems with NaOH assisted with H2O. The consumption of NaOH was reduced by 97% with respect to the NaOH aqueous systems, maintaining a comparable yield of Mg(OH)2 extraction, i.e. 64.8-66%. The capture of CO2 from a CO2-N2 gas mixture was tested at ambient conditions using a Mg(OH)2 aqueous slurry. Mg(OH)2 almost fully dissolved and reacted with dissolved CO2 by forming Mg(HCO3)2 which remained in equilibrium storing the CO2 in the aqueous solution. The CO2 balance of the process was assessed from the emissions derived from the power consumption for NaOH production and Mg(OH)2 extraction together with the CO2 captured by Mg(OH)2 derived from dunite. The process resulted as carbon neutral when dunite is reacted at 250 °C for durations of 1 and 3 hours and CO2 is captured as Mg(HCO3)2.
ABSTRACT
Referees and assistant referees are submitted to high physical stress during matches. Pressure to make decisions in front of large crowds is another potential stressor. These two stressors can impair attention executive control, depending on physical fitness and individual vulnerability or resilience to situational pressure. Error percentage for referees and assistants may reach around 14% during a soccer match. Although previous studies have suggested that soccer referees and assistants should take cognitive assessments, they are only required by Fédération Internationale de Football Association (FIFA) to demonstrate knowledge of the rules and pass annually in a fitness test (FIFA-Test). This study aimed to assess attention performance in referees and assistants before and after the mandatory FIFA-Test. It is hypothesized that the high physical demands associated with the pressure to pass the FIFA-Test would interfere with attention performance. The sample included 33 referees and 20 assistants. The Continuous Visual Attention Test (CVAT) consisted of a 15-min Go/No-go task. Performance in the CVAT is based on four variables: omission and commission errors, reaction time, and variability of reaction time (VRT). Failure in the CVAT was defined by a performance below the 5th percentile of the age- and sex-matched normative data in at least one variable of the CVAT. Before the FIFA-Test all participants performed the CVAT. The second CVAT began 3-7 min directly following completion of the FIFA-test. Considering only the officials who passed both the FIFA-Test and the first CVAT (19 referees and 15 assistants), 44% (9 referees and 6 assistants) exhibited a performance decline in the second CVAT. A significant increase in VRT was found after the high intensity exercise. As increase in VRT is thought to reflect executive dysfunctions and lapses of attention, we concluded that physical fitness alone may not be enough to help officials cope with the physical and contextual stresses associated with the FIFA-Test. These data suggest that over 35% of soccer referees and their assistants who were considered physically able to referee matches may not be mentally prepared for the attentional demands of refereeing soccer matches.
ABSTRACT
Introduction: Soccer referees need excellent conditioning to withstand the physical and psychological demands of games.Objective: To compare the hemodynamic variables, speed, cadence, and distance coursed of referees during soccer gamesof series A and B in Rio de Janeiro, Brazil. Material and method: The total number of decisions made during the 10 soccer matches evaluated was 1,224 observabledecisions of 10 professional Soccer referees (one per soccer match: 5 in series A and 5 in series B). We used a frequency meter(Polar, model V800, PolarFlow software) and video footage of the games (Sony, model PXW-Z150, 4K). The moments considered were: the decision, 15 seconds that preceded it, and the period from the beginning of each stage to each decision. Were studied the hemodynamic [average heat rate (mean HR), maximum heart rate (HRmax), and minimum heart rate (HRmin)]and motion variables [average speed (Vmed), maximum speed (Vmax), average cadence (cadencemed), maximum cadence(cadencemax), minimum cadence (cadencemin), and distance covered]. Descriptive measures were used to present the resultsof the variables studied and the Students T-Test for independent samples to test the study hypotheses. The significance levelwas set at 95% (P <0.05). Results: The matches of series A had a greater number of interventions and greater hemodynamic load at the exact momentof the decision than those of series B. significantly (P <0.05): mean HR, HRmax, HRmin, Vmax, Cadencemed, and Cadencemax in seriesA were higher compared to series B. In the 15 seconds before the decisions: mean HR, HRmax, and HRmin in series A were higherthan in series B, and Vmed in series B was higher in relation to series A. At the exact moment of the decisions: mean HR in seriesA was higher in relation to series B...(AU)
Introducción: Los árbitros de fútbol necesitan un excelente acondicionamiento para soportar las exigencias físicas y psicológicas de los partidos. Objetivo: Comparar las variables hemodinámicas [frecuencia cardíaca media (mean HR), frecuencia cardíaca máxima (HRmax)y frecuencia cardíaca mínima (HRmin)] y desplazamiento [velocidad media (Vmed), velocidad máxima (Vmax), cadencia media(cadencemed), cadencia máxima (cadencemax), cadencia mínima (cadencemin) y distancia recorrida] durante intervencionesarbitrales en partidos entre las series A y B en Río de Janeiro, Brasil. Material y método: Se analizaron 1.224 decisiones observables de 10 árbitros profesionales de fútbol cada uno en 1 partido(10 partidos del Campeonato Carioca: 5 en la serie A y 5 en la B). Se utilizaron frecuencímetros (Polar, modelo V800, softwarePolarFlow) y secuencias de video de los juegos (Sony, modelo PXW-Z150, 4K). Los momentos considerados fueron: la decisión,los 15 segundos que la precedieron y el tiempo desde el inicio de cada etapa hasta cada decisión. Resultados: Los partidos de la serie A tuvieron mayor número de intervenciones y mayor carga hemodinámica en el momentoexacto de la decisión que los de la serie B. significativamente (p <0,05): mean HR, HRmax, HRmin, Vmax, cadencemed y cadencemaxin la serie A fueron mayores que en la serie B. En los 15 segundos previos a las decisiones: mean HR, HRmax y HRmin en la serieA fueron mayores con relación a la serie B, la Vmed en la serie B fue mayor en relación a la serie A. Conclusión: Las intervenciones de los árbitros generalmente se realizan bajo presión hemodinámica elevada. Los partidosdisputados en la serie A requieren un número de intervenciones e intensidad hemodinámica superior a los partidos de laserie B...(AU)
Subject(s)
Humans , Female , Soccer , Hemodynamics , Physical Fitness , Physical Functional Performance , Heart Rate , Negotiating , Sports , Sports MedicineABSTRACT
Introducción: El árbitro de fútbol tiene un relevante papel en la práctica de la modalidad y necesita de excelente condición física. El objetivo del presente estudio fue analizar la relación entre la frecuencia cardíaca y la distancia recorrida por los árbitros de fútbol de campo durante sus actuaciones en los juegos. Material y método: Se realizó una amplia búsqueda de artículos, sin restricción de fechas, en las siguientes bases de datos electrónicas: Pubmed, Scielo y Google académico, siendo la última búsqueda efectuada el día 10/09/2017. Se utilizaron los siguientes términos de búsqueda: ("frecuencia cardíaca" o "heartrate" o "heart rate determination") AND ("distancia" o "distance" o "distance perception" o "vertical dimensión") AND (árbitro de fútbol o "soccer referee" or "football referee"). Resultados: Se encontraron 78 artículos con potencial relevancia, 27 artículos contemplaron todos los criterios inclusión, sumando 428 árbitros de fútbol, analizados en 2.936 partidos de la modalidad. Conclusión: Los árbitros necesitan una preparación muy específica. Recorren grandes distancias en los partidos, 10,36 ± 1,11 km por juego, pero de forma muy específica. Cambian mucho de dirección, de intensidad, de velocidad y rango de frecuencia cardíaca, esto sucede varias veces de forma no progresiva. En la mayoría de los juegos, se desplazan en baja intensidad, pero los estímulos de alta intensidad son muy intensos y duran muy poco de 2 a 4 segundos en su mayoría, estando directamente en los que en esas ocasiones llegan a alcanzar el 97% de su FCmáx. Se sugiere como una aplicación práctica una atención especial en la preparación y el análisis de los procesos decisivos. Los árbitros deben ser entrenados, evaluados y cuantificados en circunstancias que se asemejen a las condiciones de juego, tanto física, como psicológicamente. Es necesario enlazar las demandas físicas con las cognitivas en los entrenamientos y pruebas que asemejen a los ambientes de los partidos
Introduction: The football referee has an important role in the practice of the sport, requiring excellent physical conditioning. The objective of the present study was to analyze the relationship between heart rate and distance covered by field soccer referees during their performances in games. Material and method: A broad search of articles was carried out, without restriction of dates, in the following electronic databases: Pubmed, Scielo and Google academic, being the last search carried out on 10/09/2017. The following search terms were used: ("heart rate" or "heart rate determination") AND ("distance" or "distance perception" or "vertical dimension") AND Results: There were 78 articles with potential relevance, 27 articles included all the inclusion and exclusion criteria, totaling 428 soccer referees, analyzed in 2,936 games of the modality. Conclusion: The referees need a very specific preparation. They travel long distances in games, 10.36 ± 1.11 km per game, but in a very specific way. They vary greatly in direction, intensity, speed and range of heart rate, this happens several times in a non-progressive way. They work in matches with a FCmed ranging around 158,88 ± 3,99 bpm and, in most games, they move in low intensity, but high intensity stimuli are very intense and last very little from 2 to 4 seconds, being directly connected to the crucial bids, on these occasions they reach 97%of their FCmáx. Finally, it is suggested as a practical application a special attention is needed in the preparation and analysis of decision-making processes. Referees need to be trained, evaluated and quantified in circumstances that resemble game conditions, both physically and psychologically. It is necessary to ally physical demands with cognitive, that resemble the environments of the matches, in the trainings and tests
Subject(s)
Humans , Heart Rate/physiology , Soccer , Athletic Performance , Exercise Tolerance , Running/physiology , Anaerobic Threshold/physiologyABSTRACT
O objetivo do presente estudo foi investigar se, para crianças, errar e roubar constituem ações conceitualmente equivalentes entre si na conduta do árbitro de futebol, e se existe divergência de opinião entre meninos e meninas. Para tanto, utilizou-se um questionário fechado contendo três perguntas sobre a conduta dos árbitros de futebol durante as partidas da modalidade, aplicado a 46 crianças (25 meninos e 21 meninas) de oito a onze anos de idade (idade: 9,6 ± 0,83 anos), numa escola municipal do Rio de Janeiro. Para verificar a associação entre as respostas, o que sugere coerência na opinião da criança, e para verificar se há diferença de opinião entre os gêneros, empregou-se o teste de Qui-quadrado de Pearson. Observou-se que mais da metade da amostra relatou conhecer o papel do árbitro e mostrou coerência ao responder as questões. Isso pode refletir um nível de maturidade para compreender perguntas e julgar o árbitro. Não houve diferença estatística significativa entre meninos e meninas quanto à concordância das respostas. Assim, a maioria respondeu que, quando os árbitros erram, não o fazem de propósito. Sugere-se o trabalho com amostras maiores e a inclusão dos responsáveis pelas crian- ças em estudos futuros.
The objective of the present study was to investigate whether, for children, to err and to steal are actions conceptually equivalent to each other in the conduct of the soccer referee, and if there is divergence of opinion between boys and girls. For that, it was used a closed questionnaire containing three questions about the conduct of soccer referees during the games of the modality, applied to 46 children (25 boys and 21 girls) from eight to eleven years old (age: 9.6 ± 0.83 years), in a municipal school in Rio de Janeiro. To verify the association between the answers, which suggests coherence in the child's opinion, and to verify if there is a difference of opinion between the genres, the Pearson Chi-square was used. It was observed that more than half of the sample reported knowing the role of the referee and showed coherence in answering the questions. This may reflect a level of maturity to understand questions and judge the referee. There was no significant statistical difference between boys and girls as to the agreement of the answers. Thus, most answered that, when the referees err, they do not do it on purpose. It is suggested to work with larger samples and to include those responsible for the children in future studies.
El objetivo del presente estudio fue analizar si, para niños, errar y robar constituye acciones conceptualmente equivalentes entre sí en la conducta del árbitro de fútbol, y si existe divergencia de opinión entre niños y niñas. Para ello, se utilizó un cuestionario cerrado que conten- ía tres preguntas sobre la conducta de los árbitros de fútbol durante los partidos de la modalidad, aplicado a 46 niños (25 niños y 21 niñas) de ocho a once años de edad (edad: 9,6 ± 0,83 años), en una escuela municipal de Río de Janeiro. Para verificar la asociación entre las respuestas, lo que sugiere coherencia en la opinión del niño, y para verificar si hay diferencia de opinión de los géneros en este estudio se utilizó el Chi-cuadrado de Pearson. Se observó que más de la mitad de la muestra relató conocer el papel del árbitro y mostró coherencia al responder a las preguntas. Esto puede reflejar un nivel de madurez para entender preguntas y juzgar al árbitro. No hubo diferencia estadística significativa entre niños y niñas en cuanto a la concordancia de las respuestas, así, la mayoría respondió que, cuando los árbitros se equivocan, no lo hacen de propósito. Se sugiere el trabajo con muestras mayores y la inclusión de los responsables de los niños en estudios futuros.
Subject(s)
Humans , Male , Female , Child , Soccer , Decision Making , Sense of Coherence , Sports , Child , IntentionABSTRACT
Introduction: The aim of this study was to analyze the injuries affected in young soccer athletes of high performance categories, under (U) -11, U-13, U-15, U-17 and U-20 years and the associations between the variables related the injuries. Material and method: Data were collected from medical records of the medical department of 143 injured athletes belonging to a club in the first division of the Brazilian Championship. The young athletes were evaluated in the following categories: under (U) -11, n = 30 (10.45 ± 0.5 years), U-13, n = 34 (12.15 ± 0.3 years) U-15, n = 23 (14.56 ± 0.4 years), U-17, n = 24 (16.52 ± 0.5 years), U-20, n = 32 (18.24 ± 0.6 years). Data collection was conducted from January 2014 to November 2014 (11 months). The data were analyzed and classified according to the categories and the lesions identified as per the recommendations of the study group in injury FIFA Medical Assessment and Research Centre. Results: The results showed that there was a total of 200 lesions in all categories, the teams U-15, U-17, U-20 stood out with the greatest occurrences of injuries (p<0.05) and index of injuries (p<0.05). The Pearson correlation test showed a positive and significant coefficient of correlation (r = 0.879; p < 0.05) between index of injuries and hours of game. Conclusions:It was observed that the occurrence and characteristics of lesions of young soccer players in different categories are higher according to the increasing number of games and that the older groups demonstrate a greater number of lesions more similar to those in adults
Introducción: El objetivo del estudio fue analizar las lesiones en los jóvenes futbolistas en categorías de alto rendimiento barro (SUB) -11, SUB -13, SUB-15, SUB-17 and SUB-20 años y las asociaciones entre las variables relacionadas con las lesiones. Material y métodos: Se recogieron datos de los registros médicos del departamento médico de 143 jóvenes futbolistas pertenecientes a un club de la primera división del Campeonato Brasileño. Los jóvenes futbolistas fueron evaluados en las siguientes categorías: SUB -11, n = 30 (10,45 ± 0,5 años), SUB-13, n = 34 (12,15 ± 0,3 años), SUB-15, n = 23 (14,56 ± 0,4 años), SUB-17, n = 24 (16,52 ± 0,5 años) y SUB-20, n = 32 (18,24 ± 0,6 años). La recolección de datos se llevó a cabo a partir de enero 2014 a noviembre 2014 (11 meses). Los datos fueron analizados y clasificados por las categorías y las lesiones identificadas de acuerdo con las recomendaciones del grupo de estudio en la lesión de Evaluación Médica de la FIFA y el Centro de Investigación. Resultados: Los resultados mostraron que hubo un total de 200 lesiones en todas las categorías. Los equipos B-15, B-17 y B-20 se destacaron con las mayores ocurrencias de lesiones (p<0,05) y el índice de lesiones (p<0,05). La prueba de correlación de Pearson mostró un coeficiente de correlación positivo y significativo (r = 0,879; p <0,05) entre el índice de lesiones y horas de juego. Conclusiones: Se observó que la incidencia y características de las lesiones de los jóvenes futbolistas en diferentes categorías son más altos de acuerdo con el aumento del número de juegos y que los grupos de mayor edad demuestran un mayor número de lesiones más similares a las de los adultos
Subject(s)
Humans , Child , Adolescent , Young Adult , Athletic Injuries/epidemiology , Soccer/injuries , Brazil/epidemiology , Trauma Severity Indices , Age DistributionABSTRACT
O estudo identificou, sob o prisma da adequabilidade, qual o melhor modelo de periodização do treinamento esportivo (PTE). Foram considerados dois indicadores: a estrutura da periodização e a forma de modulação da carga. Foi utilizada a metanálise como ferramenta metodológica. 103 citações foram levantadas numa pesquisa sistemática, em bases de dados. A avaliação pelos critérios estabelecidos indicou cinco modelos de PTE passíveis de estudo. A análise estatística, empregando o tamanho efeito (TE), gerou um Índice de Adequabilidade (IADEQ) e a classificação dos modelos em: Muito Bom - Matveev (IADEQ = 3,44; TE = 1,13); Bom - Verkhoshansky (IADEQ = 2,88; TE = 0,57), Bompa (IADEQ = 2,66; TE = 0,34) e Regular - ATR (IADEQ = 1,96; TE = -0,37), Forteza (IADEQ = 2,25; TE = -0,07).
The aim of this study was to identify using the adequability pattern method, which model of periodization suite better to sport training observed at bibliographic research. It utilized as indicators the structure of periodization and the modulation pattern of workload. The methodological tool of this study was meta-analysis. Were appraised 103 citations. Analysis of the collected material, assessed through the statistic tool size-effect (TE made it possible to established an Adequability Index (IADEQ) and then, categorize the models as : Very Good - Matveev (IADEQ = 3,44; TE = 1,13); Good - Verkhoshansky (IADEQ = 2,88; TE = 0,57), Bompa (IADEQ = 2,66; TE = 0,34) e Regular - ATR (IADEQ = 1,96; TE = -0,37), Forteza (IADEQ = 2,25; TE = -0,07).
El estudio identificó, bajo prisma de la adaptabilidad, cual es lo mejor modelo de periodización del entrenamiento deportivo (PTE). Fueron considerados dos indicadores: la estructura de la periodización y la forma de modulación de la carga. Fue utilizada la metanálisis como herramienta metodológica. 103 citaciones habían sido levantadas. La evaluación por los criterios establecidos indicó cinco modelos de PTE pasibles de estudio. El análisis estadístico, empleando el tamaño efecto (TE), generó un Índice de Adaptabilidad (IADEQ, y la clasificación de los modelos en: Muy Bueno - Matveev (IADEQ = 3,44; TE = 1,13); Bueno - Verkhoshansky (IADEQ = 2,88; TE = 0,57), Bompa (IADEQ = 2,66; TE = 0,34) y Regular - ATR (IADEQ = 1,96; TE = -0,37), Forteza (IADEQ = 2,25; TE = -0,07).