ABSTRACT The development of aquaculture through the cultivation of what are considered unconventional species is an option with the potential to solve the problem of food scarcity. The aim of the present study was to evaluate the zootechnical performance of juvenile Pomacea haustrum fed different commercial diets, and subjected to different levels of salinity. After seven P. haustrum spawn had hatched in the laboratory, the juveniles were randomly selected and transferred to the rearing containers. Two different commercial diets were offered: rabbit feed with a high proportion of ingredients rich in crude vegetable protein (VP), and dog food containing balanced levels of ingredients rich in crude vegetable and animal protein (MP). The selected juveniles were randomly stocked at different salinities (0, 2 and 4 parts per thousand - ppt). The experiment lasted 65 days. Twenty-one hours after the start of the experiment, 100% of the individuals reared at a salinity of 4 ppt had died. There was a significant difference (p ≤ 0.05) between the results for zootechnical performance (average final weight, weight gain, average final growth, specific growth rate, protein efficiency and apparent feed conversion) for animals reared in fresh water or at a salinity of 2 ppt, regardless of the type of diet. The origin of the protein in the diet had no significant effect on the zootechnical performance of the individuals; however, the salinity of the water impaired development of the animals in direct proportion to its concentration. scarcity P laboratory containers offered VP, VP , (VP) MP. MP . (MP) 0, 0 (0 ppt. ppt) 6 days Twentyone Twenty one 100 died p 0.05 005 05 gain rate conversion however concentration (VP (MP ( 10 0.0 00 1 0.

RESUMO: O objetivo foi avaliar parâmetros hematológicos e bioquímicos após teste em novo ambiente, e o desempenho zootécnico de Oreochromis niloticus classificado como proativo ou reativo. No experimento 1, machos de tilápia do Nilo com peso médio de 128,33 ± 34,17 g foram mantidos em sistema de recirculação de água (RAS). Imediatamente após a classificação, foram coletadas amostras de sangue de 20 animais reativos e 20 proativos. No experimento 2 foram classificados 60 machos proativos e 60 reativos, com peso médio de 88,23 ± 21,59 g, os quais foram divididos nos seguintes tratamentos: PT (40 animais proativos), RT (40 reativos) MT (20 proativos + 20 reativos). Os animais foram alimentados duas vezes ao dia durante 90 dias. No experimento 1, os animais reativos apresentaram maior hemoglobina e cortisol e menor quantidade de leucócitos. No experimento 2, o ganho em peso foi maior nos animais proativos (PT) e nos animais reativos (RT); porém, a melhor conversão alimentar foi obtida nos animais reativos. A taxa de sobrevivência foi menor no grupo de animais do tratamento MT. Já a hemoglobina e a glicose tiveram valores inferiores para os animais proativos e para aqueles que estavam misturados, no grupo MT. O colesterol foi superior nos animais PT. Conclui-se que variáveis como hemoglobina, cortisol, leucócitos e colesterol têm maior probabilidade de sofrer alterações entre traços de personalidade. Ainda, pode-se concluir que O. niloticus reativos e proativos, cultivados em ambientes separados, apresentam o mesmo potencial de ganho em peso, porém, a conversão alimentar dos reativos é melhor. RESUMO ambiente reativo 1 12833 128 33 128,3 3417 34 17 34,1 RAS. RAS . (RAS) classificação 6 8823 88 23 88,2 2159 21 59 21,5 tratamentos 40 (4 , proativos) (2 9 dias (PT (RT) porém misturados Concluise Conclui se personalidade Ainda podese pode separados 1283 12 3 128, 341 34, (RAS 882 8 88, 215 5 21, 4 ( (RT

ABSTRACT: To evaluate hematological and biochemical parameters after testing in a new environment, and the zootechnical performance of Oreochromis niloticus classified as proactive or reactive. In experiment 1, male Nile tilapia with an average weight of 128.33 ± 34.17 g were kept in a recirculating aquaculture system (RAS). Immediately after classification, blood samples were collected from 20 reactive and 20 proactive animals. In experiment 2, 60 proactive and 60 reactive males were classified, with an average weight of 88.23 ± 21.59 g, which were divided into the following treatments: PT (40 proactive animals), RT (40 reactive) MT (20 proactive + 20 reactive ). Animals were fed twice daily for 90 days. In experiment 1, reactive animals had higher amounts of hemoglobin and cortisol and lower amounts of leukocytes detected. In experiment 2, weight gain was greater in proactive animals (PT) and reactive animals (RT); however, the best feed conversion was obtained in reactive animals. The survival rate was lower in the MT treatment group of animals. Hemoglobin and glucose had lower values for proactive animals and for those that were mixed, in the MT group. Cholesterol was higher in animals PT. It is concluded that variables such as hemoglobin, cortisol, leukocytes and cholesterol are more likely to undergo changes between personality traits. Furthermore, it can be concluded that reactive and proactive O. niloticus, grown in separate environments, have the same potential for weight gain; however, the food conversion of reactive ones is better. ABSTRACT environment 1 12833 128 33 128.3 3417 34 17 34.1 RAS. RAS . (RAS) classification 2 6 8823 88 23 88.2 2159 21 59 21.5 treatments 40 (4 animals, , animals) (2 ) 9 days detected (PT (RT) however mixed traits Furthermore O environments better 1283 12 3 128. 341 34. (RAS 882 8 88. 215 5 21. 4 ( (RT

Resumen El artículo aborda el tema de las estructuras fundamentales de la imaginación en los colectivos políticos en la ciudad de Bogotá, entendido como un proceso de racionalización del poder y de enseñanza institucional. Objetivo: analizar los cambios en la imaginación política de los colectivos juveniles para entender su significado de valor frente a la realidad social del país. Justificación: se resalta la importancia de la imaginación, ya que incide en los productos, las relaciones, los simbolismos y las estéticas que se construyen dentro de la cultura y que hacen parte del sentido dado al tejido social. Metodología: es una investigación de tipo hermenéutico-fenomenológico a partir del análisis de contenido, en la que se realiza un rastreo geo referencial de los colectivos en la ciudad de Bogotá para luego ser abordados con una entrevista semiestructurada a profundad. Resultados: la tendencia identificada en la imaginación de los colectivos políticos se mueve en medio de la dinámica dialéctica de la imaginación instituida y la imaginación instituyente, a partir de dos núcleos de pensamiento: la dominación y la resistencia. Conclusiones: la imaginación de los colectivos políticos está condicionada por los imperativos pulsionales del sujeto, en el cual las representaciones subjetivas se explican como respuesta al medio objetivo, en este caso, las medidas coercitivas y represivas del orden estatal generan imaginarios de resistencia.

Abstract This article addresses the fundamental structures of imagination in political collectives in the city of Bogotá, understood as a process of rationalizing power and institutional teaching. Objective: to analyze the changes in the political imagination of youth collectives to understand their value attribution in relation to their country’s social reality. Justification: the importance of imagination is highlighted, as it influences the products, relationships, symbols, and aesthetics constructed within the culture, which are part of the meaning given to the social fabric. Methodology: it is a hermeneutic-phenomenological research based on content analysis, carrying out a georeferential tracing of the collectives in the city of Bogotá, followed by in-depth semi-structured interviews. Results: the identified trend in the imagination of political collectives moves within the dialectical dynamic of instituted imagination and instituting imagination, based on two core thoughts: domination and resistance. Conclusions: the imagination of political collectives is conditioned by the subject's instinctual imperatives, in which subjective representations are explained as a response to the objective environment. In this case, the coercive and repressive measures deployed by the State order generate imaginaries of resistance.

Resumo Este artigo aborda as estruturas fundamentais da imaginação em coletivos políticos na cidade de Bogotá, entendidas como um processo de racionalização do poder e do ensino institucional. Objetivo: analisar as mudanças na imaginação política dos coletivos juvenis para entender sua atribuição de valor em relação à realidade social de seu país. Justificativa: destaca-se a importância da imaginação, pois ela influencia os produtos, as relações, os símbolos e a estética construídos na cultura, que fazem parte do significado dado ao tecido social. Metodologia: trata-se de uma pesquisa hermenêutico-fenomenológica baseada na análise de conteúdo, realizando um rastreamento georreferencial dos coletivos na cidade de Bogotá, acompanhado de entrevistas semiestruturadas em profundidade. Resultados: a tendência identificada na imaginação dos coletivos políticos se move dentro da dinâmica dialética da imaginação instituída e da imaginação instituinte, com base em dois pensamentos centrais: dominação e resistência. Conclusões: a imaginação dos coletivos políticos é condicionada pelos imperativos instintivos do sujeito, nos quais as representações subjetivas são explicadas como uma resposta ao ambiente objetivo. Nesse caso, as medidas coercitivas e repressivas da ordem estatal geram imaginários de resistência.

Resumen Gmelina arborea es una especie que ostenta valor económico en los mercados forestales, esencialmente por la versatilidad de su biomasa, su rápido crecimiento y la calidad de su madera. Los objetivos principales de esta investigación fueron evaluar la dendrometría, la biomasa, el suelo y las propiedades físicas y mecánicas de la madera en dos rodales de 18 años. En parcelas rectangulares de 1000 m2 se recabó información dasométrica de 20 árboles, además de fracciones de madera para ensayos físicos-mecánicos en laboratorio. En términos estadísticos, la G. arborea del rodal mezclado presentó mayor diámetro (7.3 %) y biomasa del fuste (5.1 %), además de un impacto en las propiedades mecánicas (8.1 %) y la dureza en sus diferentes ejes (long. 6.2 %, rad. 1.5 % y tang. 6.3 %). Se deduce que los rodales mezclados contribuyen a una mayor biomasa y a madera de mejor resistencia y calidad en G. arborea.

Abstract Gmelina arborea is a species that holds economic value in forest markets, primarily due to the versatility of its biomass, rapid growth, and timber quality. The main objective of this research was to evaluate the dendrometry, biomass, soil, and the physical and mechanical properties of the wood in two 18-year-old stands. In rectangular plots of 1000 m², dasometric information from 20 trees was collected, in addition to wood fractions for physical-mechanical tests in the laboratory. Statistically, mixed-stand G. arborea exhibited a larger diameter (7.3%) and stem biomass (5.1%), as well as an impact on mechanical properties (8.1%) and hardness on its various axes (long. 6.2%, rad. 1.5%, and tang. 6.3%). It is inferred that mixed stands contribute to greater biomass and better resistance and quality of wood in G. arborea.

Resumen Introducción: Semaprochilodus laticeps es una especie de pez de agua dulce originaria de la cuenca del Orinoco, explotada en Colombia en dos etapas distintas de su ciclo de vida: alevín (para el comercio ornamental) y adulto (para el mercado de consumo). Esta doble explotación de alevines y adultos genera preocupación sobre la estabilidad poblacional de la especie. Objetivo: Evaluar la sostenibilidad de la explotación de la especie en estas dos etapas de vida. Método: Entre junio y diciembre de 2017 se muestrearon 1 277 ejemplares de S. laticeps. Los parámetros poblacionales se estimaron utilizando datos de frecuencia de tallas con la rutina ELEFAN 1 del paquete FISAT II. La longitud de primera madurez (Lm) y la de máximo rendimiento (Lopt) se determinaron mediante ecuaciones de Froese y Binohlan. El análisis de la población virtual se realizó basándose en el análisis de cohorte de longitud de Jones. Resultados: Los parámetros poblacionales fueron los siguientes: K = 0.75, L∞ = 53.1 cm LE, Z = 2.92 año-1, M = 1.24 año-1 y F = 1.68. Lm se estimó en 29.6 cm SL y Lopt en 33.4 cm SL. En particular, el 96.3 % del pescado capturado en la pesquería de consumo superó Lm y el 80 % superó Lopt. El análisis de la población virtual sugirió que una fracción muy baja (0.85 %) de la población fue capturada como alevines, posiblemente atribuible a la mortalidad natural. Conclusiones: Con base en los hallazgos, al no identificarse indicadores de sobreexplotación, se recomienda continuar con el doble uso de S. laticeps. Se recomienda mantener las medidas de protección existentes, así como una veda durante el período reproductivo, para garantizar una explotación pesquera sostenible. Los resultados obtenidos pueden servir como referencia para analizar la situación de otras especies actualmente capturadas para el mercado tanto ornamental como de consumo.

Abstract Introduction: Semaprochilodus laticeps is a freshwater fish species native to the Orinoco Basin that is exploited in Colombia at two different stages of its life cycle: fry (for the ornamental trade) and adults (for the consumer market). This double exploitation of juveniles and adults raises concerns about the population stability of the species. Objective: To evaluate the sustainability of the exploitation of the species in these two life stages. Methods: 1 277 specimens of S. laticeps were sampled between June and December 2017. Population parameters were estimated from length-frequency data using ELEFAN 1 routine of the FISAT II package. Length at first maturity (Lm) and length at maximum yield (Lopt) were determined using the Froese and Binohlan equations. Virtual population analysis was performed based on Jones length cohort analysis. Results: Population parameters were as follows: K = 0.75, L∞ = 53.1 cm LE, Z = 2.92 yr-1, M = 1.24 yr-1 and F = 1.68. Lm was estimated to be 29.6 cm SL and Lopt at 33.4 cm SL. Of note, 96.3 % of the fish caught in the consumer fishery exceeded Lm and 80 % exceeded Lopt. The results of the virtual population analysis suggested that a very low proportion (0.85 %) of the population was caught as fry, possibly due to natural mortality. Conclusions: Based on the results, as no indicators of overexploitation were identified, it is recommended to continue with the dual use of S. laticeps. It is recommended to maintain the existing conservation measures, such as the closed season during the reproductive period, to ensure sustainable fishery exploitation. The results obtained can serve as a reference to analyze the situation of other species currently fished for both the ornamental (fry) and food (adult) markets.

Resumen Introducción: Las corrientes de arroyos y ríos son señales naturales que influencian las migraciones en el ciclo de vida de langostinos anfídromos. Objetivo: Evaluar el comportamiento de reotaxis en juveniles y adultos de Macrobrachium tenellum, con relación a su capacidad de respuesta a diferentes velocidades de flujos de corriente de agua en un sistema experimental de circuito cerrado. Métodos: Se utilizó un sistema de tubos PVC, con una tina para la recirculación del agua y un remanso colocado a la mitad del sistema. Se probaron flujos de agua de 10-30 cm/s para establecer las condiciones experimentales. Se evaluó el comportamiento de reotaxis sin remanso (SR) y con el remanso (CR); se probaron tres flujos de agua: FI, 14 cm/s; FII, 18.7 cm/s; y FIII, 22.1 cm/s, y un flujo control FC, 0 cm/s, con 40 juveniles, 40 hembras y 40 machos por flujo. Se identificaron tres comportamientos principales: reotaxis positiva, reotaxis negativa y sin reacción. Resultados: Tanto para SR como CR los flujos de agua estimulan mayormente la reotaxis positiva y la respuesta de comportamiento es diferente según la velocidad del flujo de agua y si son juveniles, hembras o machos. En CR hubo una mayor respuesta de los langostinos a seguir nadando en contra de la corriente cuando estos ingresaban al remanso. En un ángulo recto, el flujo de agua constante superior a 23.2 cm/s dificulta el nado contra corriente de esta especie. Conclusiones: La respuesta de reotaxis positiva fue la que mayor predominó en juveniles, hembras y machos de M. tenellum.

Abstract Introduction: The currents of streams and rivers are natural signals that influence the migrations in the life cycle of amphidromous shrimp. Objective: To evaluate the rheotaxis behavior in juveniles and adults of Macrobrachium tenellum, in relation to their response capacity to different water currentspeeds in a closed-loop experimental system. Methods: A PVC pipe system was used, with a tub for water recirculation and a backwater placed in the middle of the system. Water flows of 10-30 cm/s were tested to establish the experimental conditions. Rheotaxis behavior without backwater (SR) and with backwater (CR) was evaluated; three water flows were tested: FI, 14 cm/s; FII, 18.7 cm/s; and FIII, 22.1 cm/s, and a control FC flow, 0 cm/s, with 40 juveniles, 40 females and 40 males per flow. Three main behaviors were identified: positive rheotaxis, negative rheotaxis, and no reaction. Results: For both SR and CR, water flows stimulate positive rheotaxis and the behavioral response is different depending on the speed of the water flow and whether they are juveniles, females, or males. In CR there was a greater response of the prawns to continue swimming against the current when they entered the pool. At a straight angle, the constant flow of water greater than 23.2 cm/s makes it difficult for this species to swim against the current. Conclusions: The positive rheotaxis response was the most prevalent in juveniles, females, and males of M. tenellum.

RESUMEN Los agroecosistemas del nordeste argentino forman comunidades vegetales importantes. Las arvenses de hábito trepador pueden tornarse malezas. El monitoreo y detección temprana de especies perjudiciales contribuye a prevenir infestaciones y son herramientas útiles para alcanzar una agricultura sustentable. El objetivo del presente trabajo fue reconocer, describir y diferenciar 12 especies de malezas en estadios juveniles, con el fin de facilitar el monitoreo y prevenir el enmalezamiento en cultivos de yerba mate, té, mandioca, batata, maní, arroz y girasol, en 8 diferentes localidades de las provincias de Misiones, Corrientes y Chaco. Se realizaron censos de vegetación en diversos cultivos de 8 localidades. De las malezas más importantes se cosecharon propágulos que fueron conservados en heladera a 6°C. Luego, las semillas y esquejes se colocaron en sustrato inerte, con humedad controlada y a temperatura ambiente en contenedores de plástico. Se utilizó un calibre digital y flexómetro estándar; las fotografías fueron tomadas con smartphone y cámara digital. Se obtuvieron plántulas de 12 especies, las cuales fueron observadas, descritas morfológicamente, ilustradas, mensuradas sus partes, registrando sus estados fenológicos iniciales e identificadas taxonómicamente. Se presenta un cuadro comparativo de las especies estudiadas, una clave dicotómica para poder reconocerlas en campo y las ilustraciones de los diferentes taxones. Las diferencias morfológicas en estado de plántulas y plantas jóvenes son importantes y suficientes para reconocer estas 12 especies en campo y poder así elegir estrategias MIM orientadas a la sustentabilidad de los agroecosistemas de la región del nordeste argentino.

ABSTRACT Agroecosystems in northeastern Argentina form important plant communities. Climbing weeds can become invasive. Monitoring and early detection of detrimental species can contribute to preventing infestations and are useful tools to achieve sustainable agriculture. The aim of the present study was to recognize, describe, and differentiate 12 weed species in juvenile stages. This was performed to facilitate monitoring and prevent weed invasion in yerba mate, tea, cassava, sweet potato, peanut, rice, and sunflower crops in 8 different locations in the provinces of Misiones, Corrientes, and Chaco. Vegetation surveys were carried out in different crops in 8 localities. Propagules were harvested from the most important weeds and stored in the refrigerator at 6°C. Subsequently, seeds and cuttings were placed in inert substrate with controlled humidity and at room temperature in plastic containers. A digital caliper and a standard flexometer were used. Likewise, photographs were taken with a smartphone and digital camera. Seedlings of 12 species were obtained, observed, morphologically described, illustrated, their parts were measured, their initial phenological stages were recorded, and they were taxonomically identified. A comparative table of the species studied, a dichotomous key for field recognition, and illustrations of the different taxa are presented. The morphological differences in seedling and young plant stages are important and sufficient to recognize these 12 species in the field and thus be able to choose IWM strategies aimed at the sustainability of agroecosystems in the northeastern region of Argentina.

Abstract: The article studies the youth magazine Onda, published by Quimantú during the Unidad Popular period. It uses the notion of ‘cultural product’ within the framework of Raymond Williams’ proposal. It establishes that Onda functioned as a means of dispute to promote an ideal of youth committed to the country “on the road to socialism”, in a context of sociocultural transformation. Onda discussed with currents such as hippism through its graphics and the inclusion of musical groups. In addition to educating about sexuality or the political issues of the moment, it served as a platform to express youth visions and discourses through accessible, fun, ironic and educational language.

Resumen: El artículo estudia la revista juvenil Onda editada por Quimantú durante el periodo de la Unidad Popular, desde la noción de producto cultural en el marco de la propuesta de Raymond Williams. Se establece que Onda funcionó como un medio de disputa para promover un ideal de juventud comprometida con la patria “en vías al socialismo”, en un contexto de transformación sociocultural, dialogando con corrientes como el hippismo mediante su gráfica y la inclusión de grupos musicales. Además de educar en torno a la sexualidad o temas políticos del momento, sirvió de plataforma para plasmar visiones y discursos juveniles mediante un lenguaje accesible, divertido, irónico y educativo.

Resumo Introdução: A especialização precoce no esporte é um tema altamente controverso e debatido ao longo da história. A especialização precoce envolve designar um indivíduo a uma disciplina esportiva específica de forma prematura ou antecipada, geralmente ocorrendo em idades muito jovens. Objetivo: Questionar a prática da especialização precoce em crianças, tanto meninos quanto meninas, por meio do desenvolvimento de argumentos e reflexões. Desenvolvimento: Em vez de beneficiar os atletas, essa prática favorece agentes externos com interesses monetários privados. Embora à primeira vista pareça inofensiva ou até benéfica, não é realmente o que aparenta ser. Vários aspectos negativos foram evidenciados, que podem comprometer a integridade das crianças, causando problemas físicos e psicológicos, violando seus direitos e levando ao abandono precoce e ao distanciamento do exercício e do esporte. Conclusões: Treinadores e educadores físicos devem enfatizar aspectos da mente, compreender as percepções e sensações dos atletas, respeitar suas preferências e gostos, e evitar manipulação e persuasão. Portanto, os jovens devem ser incentivados a explorar várias disciplinas esportivas, promovendo o esporte como um espaço de aprendizado e desenvolvimento social, e não apenas de competição.

Resumen Introducción: La especialización temprana en el deporte es un tema altamente controvertido y debatido a lo largo de la historia, consiste en designar a una persona en una modalidad deportiva en particular antes de tiempo o en forma anticipada; normalmente, se evidencia que ocurre en edades muy prematuras. Objetivo: Cuestionar la práctica de la especialización temprana en niños y niñas, a través del desarrollo de argumentos y reflexiones. Desarrollo: Esta práctica, más que beneficiar a los deportistas, favorece agentes externos que tienen intereses monetarios privados. Aunque a simple vista pareciera inofensiva e inclusive benéfica, no lo es en realidad, ya que se han evidenciado múltiples aspectos negativos, que pueden atentar contra la integridad de los niños y niñas, hecho que ocasiona problemas físicos y psicológicos, así como vulnera sus derechos y genera el abandono o distanciamiento temprano del ejercicio y del deporte. Conclusiones: Los entrenadores y educadores físicos deben dar relevancia a aspectos de la mente; entender las percepciones y sensaciones de los atletas; respetar las preferencias y gustos; evitar la manipulación y persuasión de aquellos. Por tal razón, debe permitirse a los jóvenes explorar múltiples modalidades deportivas y, a partir de allí, fomentar el deporte como un espacio de aprendizaje y desarrollo social, no meramente como competencia.

Abstract Introduction: Early specialization in sports is a highly controversial and debated topic throughout history, it involves designating an individual to a particular sport discipline prematurely or in an anticipatory manner, typically occurring at very young ages. Objective: To question the practice of early specialization in children, both boys and girls, through the development of arguments and reflections. Development: Rather than benefiting athletes, this practice favors external agents with private monetary interests. Although at first glance, it may seem harmless or even beneficial, it is not truly what it appears to be. Multiple negative aspects have been evidenced, which can jeopardize the integrity of children, causing physical and psychological issues, violating their rights, and leading to early abandonment and distancing from exercise and sports. Conclusions: Coaches and physical educators should emphasize aspects of the mind, understand athletes’ perceptions and sensations, respect their preferences and tastes, and avoid manipulation and persuasion. Therefore, young people should be allowed to explore multiple sports disciplines, thereby fostering sports as a space for learning and social development rather than mere competition.

Resumen Los colectivos estudiantiles que afrontan transiciones educativas, desde la escuela secundaria hacia el nivel superior, como así también aquellas que tienen lugar al interior de esta última fase escolar, se adentran en procesos de aprendizaje personales, institucionales y académicos para lograr afiliarse y habitar nuevos espacios académicos. El presente artículo propone, a la luz de los actuales aportes teórico-normativos, una caracterización de las transiciones educativas experimentadas por jóvenes, las que se dividen en dos grupos, a saber: las que se dan interniveles (escuela secundaria-universidad) y las que tienen lugar intra nivel superior (universidad-institutos superiores). A partir de la recuperación de hallazgos situados en dos investigaciones recientes, realizadas en la ciudad de Bahía Blanca, provincia de Buenos Aires, se propone caracterizar estos pasajes transicionales educativos juveniles. Para eso, se retoman las voces estudiantiles de quienes nos ofrecen sus miradas en torno a la diversidad de factores contextuales, socioinstitucionales y subjetivos que incidieron en estas transiciones, en tanto apuestas para continuar estudiando en este último nivel.

Abstract The student groups that face educational transitions, from secondary school to the higher level as well as those that take place within this last school phase, enter into personal, institutional and academic learning processes to achieve affiliation and inhabit new academic spaces. This article proposes, in light of current theoretical-normative contributions, a characterization of the educational transitions experienced by young people, which are divided into two groups, namely: those that occur inter-levels (secondary school - university) and those that take place intra-higher level (university - higher institutes). Based on the recovery of findings located in two recent investigations carried out in the city of Bahía Blanca, province of Buenos Aires, it is proposed to characterize these transitional youth educational passages. For this, the student voices of those who offer us their views on the diversity of contextual, socio-institutional and subjective factors that configured these transitions as bets to continue studying at this last level.

Resumo Os grupos de estudantes que enfrentam transições educativas, do ensino secundário para o nível superior, bem como aqueles que ocorrem nesta última fase escolar, entram em processos de aprendizagem pessoal, institucional e académica para conseguirem afiliação e habitarem novos espaços académicos. Este artigo propõe, à luz dos contributos teórico-normativos actuais, uma caracterização das transições educativas vividas pelos jovens, as quais se dividem em dois grupos, a saber: as que ocorrem interníveis (ensino secundário - universidade) e as que ocorrem intra-níveis. -nível superior (universidade - institutos superiores). Com base na recuperação de resultados localizados em duas investigações recentes realizadas na cidade de Bahía Blanca, província de Buenos Aires, propõe-se caracterizar essas passagens de transição educacional juvenil. Para o efeito, as vozes estudantis daqueles que nos oferecem os seus pontos de vista sobre a diversidade de factores contextuais, sócio-institucionais e subjectivos que configuraram estas transições são assumidas como apostas para continuar a estudar neste último nível.

Resumen El playero blanco (Calidris alba) es el ave playera de más amplia distribución que inverna en ambas costas de América, con registros de individuos vagabundos en el interior del continente. El 14 de septiembre de 2022, observamos y fotografiamos dos juveniles del playero blanco en una charca pequeña adyacente al Río Mezquites en el Área de Protección de Flora y Fauna de Cuatro Ciénegas, Coahuila, México. Este avistamiento representa el primer registro de esta especie en este sitio RAMSAR e incrementa su distribución continental conocida en el noreste de México, siendo además el primero documentado para el estado de Coahuila.

Abstract The Sanderling (Calidris alba) is the most widely distributed shorebird that winters on both coasts of America, with records of vagrant individuals in the interior of the continent. On 14 September 2022, we observed and photographed two juvenile Sanderlings at a small pool adjacent to the Río Mezquites in the Cuatro Ciénegas protected area, Coahuila, Mexico. This sighting represents the first record of this species in this RAMSAR site, and increases the known inland distribution in northeastern Mexico, as well as the first documented for the state of Coahuila.

Resumen Se analizaron muestras de suelo y raíces del cultivo del pepino. Se extrajeron e identificaron los nematodos fitopatógenos presentes. Juveniles de Meloidogyne incognita fueron los más abundantes en suelo, otros como Aphelenchoides sp., Pratylenchus sp., Tylenchorynchus sp., y Aphelenchus sp. se encontraron con menor presencia. De las raíces se obtuvieron hembras y huevos de M. incognita. Con el fin de encontrar alternativas a los productos químicos fumigantes utilizados en exceso, se evaluaron las rizobacterias Bacillus vallismortis, Bacillus velezensis y Pseudomonas fluorescens, que fueron fermentadas y filtradas para ponerse en contacto con estos nematodos bajo condiciones in vitro, observando su efecto cada 24 h. Los tratamientos se analizaron en concentraciones de 100 % y 50 %. El filtrado de P. fluorescens presentó la mejor actividad nematicida, ocasionando una mortalidad de 95 % en la concentración más alta y de 93 % en la concentración de 50 % a las 24 h, seguido por los tratamientos de B. vallismortis y B. velezensis con 83 y 77 % de respectivamente, en las concentraciones más altas. Los tres tratamientos ocasionaron un 100 % de mortalidad de los nematodos a 48 h de exposición, indicando, que contienen acción nematicida y pueden ser una alternativa viable para el control de estos fitopatógenos.

Abstract Soil and root samples of the cucumber crop were analyzed. Plant pathogenic nematodes present were extracted and identified. The juveniles of the root-knot nematode Meloidogyne incognita were the most abundant in soil, other such as Aphelenchoides sp., Pratylenchus sp., Tylenchorynchus sp., and Aphelenchus sp. were found in less presence. Females and eggs of M. incognita were obtained from the roots. Finding alternatives to chemicals fumigants, the rhizobacterias Bacillus vallismortis, Bacillus velezensis and Pseudomonas fluorescens were fermented and filtered to be evaluated on these filiform nematodes under laboratory conditions, observing their effect every 24 h. The treatments were evaluated at concentrations of 100 % and 50 %. The P. fluorescens filtrate was the treatment with the best nematicidal activity, causing a mortality of 95 % at the highest concentration and 93 % at the 50 % at 24 h, followed by the treatments of B. vallismortis and B. velezensis with 83 and 77 % respectively at concentrations of 100 % product. The three treatments showed 100 % mortality of the nematodes after 48 hours of exposure, indicating that these rhizobacteria contain metabolites with nematicidal action that could be a healthy alternative for the control of these phytopathogens.

RESUMEN El objetivo fue describir la tasa de tuberculosis (TB) hallada por la estrategia de búsqueda activa en adolescentes y jóvenes en tres centros penitenciarios juveniles. Realizamos detección de TB a través de un algoritmo de búsqueda activa con toma de radiografía de tórax, lectura automatizada por software de inteligencia artificial, prueba molecular de GeneXpert Ultra MTB/RIF, y evaluación clínica. Se tamizaron 640 personas, 94 (14,6%) tuvieron una radiografía de tórax anormal. De los tamizados, se obtuvo 105 pruebas de GeneXpert de los cuales 94 tuvieron radiografía anormal, 9 fueron sintomáticos respiratorios y 2 estuvieron en tratamiento antirretroviral con cuadro clínico de TB. Obtuvimos 8 (8,5%) casos de TB detectados con GeneXpert, 7 con radiografía anormal y 1 con radiografía normal. Por último, de estos 8 casos, 3 fueron tuberculosis resistente a rifampicina (TB-RR) (42,8%). La tasa de tamizados por búsqueda activa fue de 1250 por 100 000 tamizados, siendo 10 veces más que la tasa en población general. Recomendamos la inclusión de centros penitenciarios juveniles como grupos de interés para búsqueda sistemática y desarrollar intervenciones para disminuir riesgo de contagio de TB.

ABSTRACT This study aimed to describe the rate of tuberculosis (TB) found by using the active search strategy in teenagers and youths in three youth detention centers. TB was screened through the active search algorithm with chest X-ray, the automated reading was carried out by artificial intelligence software, the GeneXpert Ultra MTB/RIF molecular test, and clinical evaluation. A total of 640 individuals were screened, 94 (14.6%) had an abnormal chest X-ray. Of those screened, we obtained 105 GeneXpert tests of which 94 had abnormal X-rays, 9 were respiratory symptomatic and 2 were on antiretroviral treatment with TB clinical picture. We obtained 8 (8.5%) cases of TB detected with GeneXpert, 7 with abnormal radiography and 1 with normal radiography. Finally, of these 8 cases, 3 were cases of rifampicin-resistant tuberculosis (RR-TB) (42.8%). The rate of screening by active search was 1250 per 100,000 screened, 10 times higher than the rate in the general population. We recommend the inclusion of youth detention centers as target groups for systematic screening and the development of interventions to reduce the risk of TB infection.

ABSTRACT. Including probiotic yeasts, such as Debaryomyces hansenii, in fish diets improves aquaculture production and fish health. Some fish-isolated yeasts, like Candida tropicalis, produce antimicrobial metabolites. However, there have been no reports on their in vivo effects. We evaluated the effects of dietary administration of both yeasts on growth, survival, digestive enzyme activity, expression of intestinal barrier genes, and intestinal microbiota composition in Atractosteus tropicus juveniles. We administered diets with three concentrations of C. tropicalis (104, 106, and 108 CFU g-1), three with D. hansenii (103, 105, and 107 CFU g-1), and a control diet without yeast for 45 days. We also evaluated the antagonistic capacity of both yeasts against fish pathogens in vitro. Results showed that lower doses of C. tropicalis (104 CFU g-1) and D. hansenii (103 CFU g-1) improved growth, survival, and lipase activity. However, C. tropicalis compromised intestinal barrier integrity by reducing zo-1 expression and increasing il-8 expression while altering the microbiota to favor Desulfovibrionaceae. Conversely, D. hansenii enhanced intestinal barrier integrity by increasing the expression of muc-2, zo-1, and il-10 genes and decreasing il-8 expression without altering the microbiota, where Mycoplasma predominated. Both yeasts showed antagonistic activity against pathogens. In conclusion, the dietary inclusion of C. tropicalis did not favor the intestinal health of the fish. Conversely, D. hansenii at a concentration of 103 CFU g-1 is recommended to improve the growth, digestive function, and health of A. tropicus juveniles.