Dynein Regulators Are Important for Ecotropic Murine Leukemia Virus Infection

Indexación: Web of Science.During the early steps of infection, retroviruses must direct the movement of the viral genome into the nucleus to complete their replication cycle. This process is mediated by cellular proteins that interact first with the reverse transcription complex and later with the preintegration complex (PIC), allowing it to reach and enter the nucleus. For simple retroviruses, such as murine leukemia virus (MLV), the identities of the cellular proteins involved in trafficking of the PIC in infection are unknown. To identify cellular proteins that interact with the MLV PIC, we developed a replication-competent MLV in which the integrase protein was tagged with a FLAG epitope. Using a combination of immunoprecipitation and mass spectrometry, we established that the microtubule motor dynein regulator DCTN2/p50/dynamitin interacts with the MLV preintegration complex early in infection, suggesting a direct interaction between the incoming viral particles and the dynein complex regulators. Further experiments showed that RNA interference (RNAi)-mediated silencing of either DCTN2/p50/dynamitin or another dynein regulator, NudEL, profoundly reduced the efficiency of infection by ecotropic, but not amphotropic, MLV reporters. We propose that the cytoplasmic dynein regulators are a critical component of the host machinery needed for infection by the retroviruses entering the cell via the ecotropic envelope pathway. IMPORTANCE Retroviruses must access the chromatin of host cells to integrate the viral DNA, but before this crucial event, they must reach the nucleus. The movement through the cytoplasm-a crowded environment where diffusion is slow-is thought to utilize retrograde transport along the microtubule network by the dynein complex. Different viruses use different components of this multi-subunit complex. We found that the preintegration complex of murine leukemia virus (MLV) interacts with the dynein complex and that regulators of this complex are essential for infection. Our study provides the first insight into the requirements for retrograde transport of the MLV preintegration complex.http://jvi.asm.org/content/90/15/689

Recomendaciones de manejo usando análisis de viabilidad poblacional del berrendo peninsular endémico

A case study on the viability of small populations with a restricted distribution and reduction in habitat quality is addressed using the peninsular pronghorn (Antilocapra americana peninsularis) of Baja California Peninsula, Mexico. The present size of its wild population is less than 250 individuals, being in an IUCN Critically Endangered status. Captive management of peninsular pronghorn began in 1998 in El Vizcaino Desert with 22 founders. We predicted future trends in the pronghorn population, and assessed the risk of extinction through population viability analysis (PVA) using VORTEX. Deterministic and stochastic factors designed to simulate human activity on the landscape were evaluated for their impact on this endemic taxon. The concept of supportive breeding was assessed. The results of PVA simulations indicate that removal of founder animals to initiate the captive breeding did not significantly reduce the viability of the wild population. However, a population size <100 individuals greatly increase the risk of extinction. Also, one of the most important factors for the viability of the peninsular pronghorn population is the survival of fawns. The risk of extinction can be significantly reduced using supportive breeding. We propose that the likelihood of successful population management of peninsular pronghorn could be increased establishing a number of subpopulations across the species’ historic range and, even more importantly, the establishment of ecologically functional connections between these subpopulations to create a proper metapopulation. Captive breeding can be an important factor to decrease the probability of extinction of this subspecies. Key Words: Antilocapra americana, endangered, management, PVA, recovery.Se evaluó el riesgo de extinción de la población del berrendo peninsular (Antilocapra americana peninsularis) en la península de Baja California, México que presenta distribución restringida y deterioro en la calidad de su hábitat. En el año 2000, el tamaño de la población silvestre del berrendo peninsular era menor a 250 individuos. Se desarrolló un análisis de viabilidad de poblaciones (PVA) usando Vortex, que incluyó variables determinísticas y estocásticas, e información de 25 años para proyectar cambios en la población, y evaluar su riesgo de extinción. Con el PVA se evaluó el concepto de Reproducción de Apoyo. En 1998 se inició el manejo en cautiverio del berrendo peninsular con 22 animales fundadores. Los modelos sugirieron que una población de menos de 100 individuos incrementa considerablemente el riesgo de extinción, siendo uno de los factores más importantes para la viabilidad de la población la sobrevivencia de las crías. Se propone que el éxito del manejo de la población del berrendo peninsular puede incrementarse estableciendo subpoblaciones dentro de su rango histórico de distribución con una perspectiva metapoblacional donde se conecten las subpoblaciones. Y se concluye que la reproducción en cautiverio puede ser un factor importante para disminuir la probabilidad de extinción de esta subespecie.

Efecte de l’entrenament de resistència continu i intermitent sobre el balanç autònom, la valoració de l’esforç percebut i els nivells de lactat a la sang en subjectes sans

Objectiu La finalitat d’aquest estudi fou determinar els canvis del balanç autònom, la valoració de l’esforç percebut (VEP) i el lactat sanguini, després d’un protocol d’exercici aeròbic continu i un d’intermitent. Mètodes Participaren a l’estudi 7 homes actius i sans (33 ± 5,1 anys). Cada subjecte féu 2 protocols d’exercicis: a) un entrenament continu al 110% del llindar del lactat (CONT); el protocol CONT consistí en una cursa contínua, essent la distància recorreguda en metres igual a la distància de la sessió intermitent, i b) un entrenament intermitent al 100% de la velocitat pic en cinta (INTT). El protocol consistí en 30 min de cursa de 15 s, intercalats amb 15 s de descans passiu. El balanç autònom s’avaluà mitjançant la ràtio LF/HF abans de començar els exercicis, immediatament després de finalitzar-los, i 24 h després d’haver-los finalitzat; l’VEP s’avaluà cada 5 min en cada protocol d’exercicis, i el lactat a la sang es mesurà immediatament després d’ambdós protocols. El nivell alfa s’establí en p ≤ 0,05. Resultats El balanç autònom no mostrà diferències significatives entre ambdós protocols (p = 0,60). L’VEP durant l’exercici INTT fou considerablement superior a l’exercici CONT (p = 0,01). Els nivells de lactat a la sang no reflectiren diferències significatives (p = 0,68). Els paràmetres de variabilitat de la freqüència cardíaca en el domini del temps (mitjana RR i pNN50) no reflectiren diferències estadístiques entre ambdós protocols, amb mesuraments previs i a les 24 h de l’exercici (p = 0,24 i p = 0,61, respectivament). Conclusions Les dades suggereixen que l’entrenament intermitent es percep més intens que el continu, tot i que ambdós protocols reflectiren càrregues internes similars quant a balanç autònom i nivells de lactat a la sang

Effects of continuous and intermittent endurance exercise in autonomic balance, rating perceived exertion and blood lactate levels in healthy subjects

Purpose The aim of this study was to determinate the changes in the Autonomic Balance, Rating Perceived Exertion (RPE) and blood lactate after continuous versus intermittent exercise protocols. Methods En el estudio participaron 7 varones activos y sanos (33 ± 5,1 años). Cada sujeto realizó 2 protocolos de ejercicios: a) un ejercicio continuo al 110% del umbral del lactato (CONT); el protocolo CONT consistió en una carrera continua, siendo la distancia cubierta en metros igual a la distancia de la sesión intermitente, y b) un ejercicio intermitente al 100% de la velocidad pico en cinta (INTT). El protocolo consistió en 30 min de carrera de 15 segundos, intercalados con 15 segundos de descanso pasivo. El balance autónomo se evaluó mediante el ratio LF/HF antes de comenzar los ejercicios, inmediatamente después de finalizar los mismos, y a las 24 h de su finalización; la RPE se evaluó cada 5 min en cada protocolo de ejercicios, y el lactato en sangre se midió inmediatamente tras ambos protocolos. El nivel alfa se estableció en p ≤ 0,05. Seven active and healthy male (33 ± 5.1 years) participated in the study. Each subject performed two exercise protocols: (i) a continuous exercise at 110% of the lactate threshold (CONT). The CONT protocol consisted in continuous running, and the distance covered was the same in meters as it was in the intermittent session, and (ii) an intermittent exercise at 100% of the Peak Treadmill Velocity (INTT). The protocol consisted of 30 min of 15 s running, interspersed with 15 s of passive rest. Autonomic balance was assessed through the LF/HF ratio, before beginning the exercises, immediately finishing the exercises and 24 h post-exercise; RPE was evaluated every 5 min in each exercise protocol; and blood lactate was measured immediately after both protocols. Alpha level was set at P ≤ .05. Results Autonomic balance did not show significant differences between protocols (P = .60). RPE during INTT exercise was significantly higher than CONT exercise (P = .01). Blood lactate levels after exercise did not show significant differences (P = .68). Heart rate variability parameters in the time domain (mean RR and pNN50) show no statistical differences between both protocols pre and 24 h post exercise (P = .24 and P = .61, respectively)

Evaluation of growth, yield and calorific value of Miscanthus x giganteus (Poaceae) biomass established in south central of Chile

Se establecieron cultivos experimentales de Miscanthus x giganteus en tres sitios contrastantes del centro-sur de Chile para evaluar su crecimiento y potencial energético. Al segundo año de crecimiento el cultivo presentó grandes diferencias entre sitios, altura (52,1 a 158,2 cm), rendimiento en biomasa (1,1 a 9,0 Mg ha-1), contenido de cenizas (3,8 a 9,6%) y poder calorífico (16,64 a 18,14 MJ kg-1). La composición química de la biomasa indicó celulosa en un 36%, hemicelulosa con 22,3% y lignina con 26,9%. El análisis elemental indicó 41,9% de C y 6,6% de H. Miscanthus x giganteus presenta condiciones para su utilización en la generación de energía en Chile.Experimental crops of Miscanthus x giganteus were planted in three contrasting sites in Chile south central to evaluate its growth and energy potential. In the second year of growth, the crop exhibited large differences among sites regarding height (52.1 to 158.2 cm), biomass yield (1.1 to 9.0 Mg ha-1), ash content (3.8 to 9.6%) and calorific value (16.64 to 18.14 MJ kg-1). The chemical composition of the biomass indicated cellulose 36%, hemicellulose 22.3% and lignin 26.9%. Elemental analysis indicated C and H content of 41.9% and 6.6% respectively. Therefore, Miscanthus x giganteus offers suitable attributes to be used for energy generation in Chile.Fil: Muñoz, Fernando. Universidad de Concepción (Chile)Fil: Cancino, Jorge. Universidad de Concepción (Chile)Fil: Rodríguez, Roque. Universidad de Santiago de Compostela. Escuela Politécnica SuperiorFil: Olave, Rodrigo

Modeling natural mortality for different plant densities in dendroenergetic trials

Mortality was modelled for three species (Acacia melanoxylon, Eucalyptus camaldulensis, Eucalyptus nitens) at three plantation densities (5000, 7500, and 10000 trees ha-1) in an trial of biomass production for purposes of dendroenergetic. One modelling based on individual tree level and two mortality modelling alternatives were evaluated: four survival probability equations and eight difference equations. The individual tree survival modelling considered a logistic model, is a linear combination of variables to individual tree at current time  and the previous time as estimator, being the main variables the variation of the competition index and the variation of basal area growth between the current growth period and the previous growth period. The survival probability alternative used state variables of the stand (age, dominant height, average square diameter) as predictors, whereas the difference equations were adjusted according to age-based changes only. The models to stand levels showed better result than individual tree models, and in general, the mortality models based on difference equations presented better indicators of precision and parsimony. The rate of relative mortality was constant, i.e., (dN/dE)/N, and varied between species, revealing greater mortality, consecutively, in E. nitens, A. melanoxylon, and E. camaldulensis. Although mortality tended to be higher at greater plantation densities, stand density did not significantly affect the parameters of the adjusted models. Highlights The mortality stand level models showed better results than the individual tree models for dendroenergetic crops, and in general, the mortality models based on difference equations presented better precision indicators and parsimony. The survival probability alternative involved state variables of the stand like age, dominant height, and average square diameter as predictors, while the difference equations were fitted according to age-based changes only. Mortality tended to be higher at greater plantation densities, however stand density did not significantly affect the parameters of the mortality equations.Mortality was modelled for three species (Acacia melanoxylon, Eucalyptus camaldulensis, Eucalyptus nitens) at three plantation densities (5000, 7500, and 10000 trees ha-1) in an trial of biomass production for purposes of dendroenergetic. One modelling based on individual tree level and two mortality modelling alternatives were evaluated: four survival probability equations and eight difference equations. The individual tree survival modelling considered a logistic model, is a linear combination of variables to individual tree at current time  and the previous time as estimator, being the main variables the variation of the competition index and the variation of basal area growth between the current growth period and the previous growth period. The survival probability alternative used state variables of the stand (age, dominant height, average square diameter) as predictors, whereas the difference equations were adjusted according to age-based changes only. The models to stand levels showed better result than individual tree models, and in general, the mortality models based on difference equations presented better indicators of precision and parsimony. The rate of relative mortality was constant, i.e., (dN/dE)/N, and varied between species, revealing greater mortality, consecutively, in E. nitens, A. melanoxylon, and E. camaldulensis. Although mortality tended to be higher at greater plantation densities, stand density did not significantly affect the parameters of the adjusted models. Highlights The mortality stand level models showed better results than the individual tree models for dendroenergetic crops, and in general, the mortality models based on difference equations presented better precision indicators and parsimony. The survival probability alternative involved state variables of the stand like age, dominant height, and average square diameter as predictors, while the difference equations were fitted according to age-based changes only. Mortality tended to be higher at greater plantation densities, however stand density did not significantly affect the parameters of the mortality equations

Valor justo de madeira em pé no contexto da IAS 41: um estudo de caso com Pinus radiata

Upon seeing the forest valuation in a knowledge-based framework and, although there are studies that indicate how the Chilean forestry companies evaluate their forestry assets, existing information can be inferred only on large and medium-sized enterprises; in the case of small enterprises there are no tangible data to know what the method of valuation of its assets. To provide a critical assessment of the valuation methods commonly used for the valuation of forests, this paper has two objectives. First, to evaluate compatibility of valuation criteria based on the fair value method of the biological assets of forest companies after adopting the International Financial Reporting System (IFRS), and second, to establish a method for the proper use of IAS 41 (International Accounting Standard) in the forestry sector through case studies in Chile. Fair value was determined according to IAS 41, in an immature plantation (eight years) established with Pinus radiata, using the “cost approach” and the “income approach”. The main findings suggest that the estimation of fair value using the “income approach” valuation method becomes more precise the younger the stand, i.e. calculating fair value based on the net present value of the stand, promises more accuracy. Nonetheless, the use of growth and yield simulation software for stands of exotic species, impede widespread use of this method. Results indicate the need to harmonize methodological criteria to measure fair value in crops of forest species.Ao ver a valorização da floresta em um quadro baseado no conhecimento e embora existam estudos que indicam como as empresas florestais chilenas avaliam seus ativos florestais, a informação existente pode ser inferida apenas em grandes e médias empresas; no caso das pequenas empresas não existem dados concretos para saber o que o método de valorização de seus activos. Para fornecer uma avaliação crítica dos métodos de avaliação comumente usados para a avaliação de florestas, este artigo tem dois objetivos. Primeiro, avaliar a compatibilidade dos critérios de avaliação baseados no método de valor justo dos ativos biológicos de empresas florestais depois de adotar o Sistema de Informação Financeira Internacionais (IFRS) e, segundo, estabelecer um método para o uso adequado da NIC 41 (Norma Internacional de Contabilidade) no setor florestal por meio de estudos de caso no Chile. O valor justo foi determinado de acordo com a IAS 41, em uma plantação de imatura (oito anos) estabelecida com Pinus radiata, usando a “abordagem de custo” e a “abordagem de renda”. Os principais resultados sugerem que a estimativa do valor justo usando o método de avaliação “abordagem de renda” se torna mais precisa quanto mais jovem o estande, ou seja, calcular o valor justo com base no valor presente líquido do estande, promete mais precisão. No entanto, o uso de softwares de simulação de crescimento e produtividade para áreas de espécies exóticas impedem o uso disseminado desse método. Os resultados indicam a necessidade de harmonizar critérios metodológicos para mensurar o valor justo em culturas de espécies florestais

Uso del classroom y evaluación formativa de estudiantes de tres CETPROS públicos, UGEL 03, Lima, 2022

El presente estudio de investigación desarrollado respecto al uso del Classroom y evaluación formativa de estudiantes de tres Cetpros públicos UGEL 03 Lima 2022. Se realizó a través de la Investigación aplicada, de nivel explicativo, cuantitativo, hipotético, deductivo, con un diseño no experimental, correlacional, causal, la población de estudio estuvo conformada por estudiantes de tres Cetpros Ugel 03-Lima, con una población de 80 alumnos, se consideró una muestra de 60 estudiantes de acuerdo con el resultado de la fórmula del cálculo del tamaño de la muestra de toda la población. El instrumento utilizado para la adquisición y recopilación de los datos de las variables propuestas fue el cuestionario, corroborado por expertos, estableciendo su confiabilidad por el coeficiente de Cronbach, los resultados mostrado a través de la prueba de regresión logística ordinal, entregaron un valor de p-valor=0.000<0.05 demostrando que la variable Classroom es explicada por el modelo Pseudo R2 de Cox y Snell en un 52% y en el de Nagelkerke en un 61%, concluyendo, que la plataforma educativa Classroom influye significativamente en la evaluación formativa dé estudiantes de educación técnica productiva de Lima

Growth characteristics in diameter, height, and volume of a Eucalyptus nitens plantation with different silvicultural treatment for pruning and thinning

Chile has an important tree cover of Eucalyptus nitens (Deane and Maiden) plantations destined primarily for pulpwood production. Nevertheless, other products such as sawlogs and veneers are required because of the continually changing market for wood, as well as the need to obtain greater economic returns from the forest plantations. The present work describes the results obtained in a trial of pruning and thinning of Eucalyptus nitens plantations during eight years of control. The trial was established in 1989 and was located close to Los Alamos, Eighth Region, Chile, and involved observing an arrangement of two factors: intensity of thinning (without thinning, and thinning to 800 and 400 trees ha–1) and severity of pruning (without pruning, and pruning at 3.5 and 7.0 m), and three replications. Three measurements were taken: at the establishment of the trial, in October 1995 (6 years old), in October 1999 (10 years old), and in 2003 (14 years old). The diameter at breast height (dbh) was measured for all the trees of the plots, and the total height in a subsample of 15 trees per plot. After eight years of growth, the plots most intensely thinned reached the greatest tree growth in diameter and volume. Thinning has a significant effect in growth, but not pruning. Growth in diameter, height, and volume by tree of the 400 trees per hectare of greater dbh did not vary significantly with the treatment. The greatest volume per hectare was gained with 1100 trees ha–1 and 3.5 m pruning, with 680.0 m3 ha–1 and a mean annual increment (MAI) of 48.6 m3 ha–1 year–1.Chile posee una importante superficie de plantaciones de Eucalyptus nitens (Deane & Maiden) Maiden destinada fundamentalmente a la obtención de madera para pulpa. Sin embargo, debido a los permanentes cambios que presenta el mercado de la madera y la necesidad de obtener mayores retornos económicos de los cultivos forestales, se requiere obtener otros productos provenientes de estas plantaciones, como trozas para madera aserrada y chapas. El presente documento entrega los resultados obtenidos en un ensayo de poda y raleo en Eucalyptus nitens después de ocho años de control. El ensayo se estableció en una plantación del año 1989, ubicada cercana a la localidad de Los Alamos, VIII Región, según un arreglo factorial de dos factores: intensidad de raleo (sin raleo, 800 y 400 arb ha-1) y severidad de poda (sin poda, 3,5 y 7,0 m) y tres repeticiones. Se efectuaron tres mediciones: al establecimiento del ensayo, en octubre de 1995 (6 años de edad), y posteriormente en octubre de los años 1999 (10 años de edad) y 2003 (14 años de edad). Se midió el diámetro a la altura del pecho (dap) de todos los árboles y alturas totales en una submuestra de 15 árboles por parcela. Ocho años después de aplicado los tratamientos, las parcelas más intensamente raleadas presentan los mayores crecimientos en diámetro y volumen por árbol. El raleo tuvo un efecto significativo en el crecimiento de los árboles, no así la poda. El crecimiento en diámetro, altura y volumen por árbol de los 400 árboles de mayor dap por hectárea no varía significativamente entre tratamientos. El mayor volumen por hectárea se alcanza en el tratamiento 1.100 árb ha-1 y 3,5 m de poda con 680,0 m3 ha-1 y un incremento medio anual (IMA) de 48,6 m3 ha-1 año-1

Taper model for Eucalyptus nitens, in volcanic ash soils of the region of The Araucanía (Chile)

Se presenta un modelo de ahusamiento para Eucalyptus nitens (Deane &amp; Maiden) Maiden. Este es un modelo no lineal que fue ajustado con datos de 60 árboles con edades entre los 16 y 21 años, diámetros normales entre 11,5 y 52,0 cm, y con alturas totales entre 12,27 y 47,49 m. Cosechados en 6 rodales localizados en 3 comunas de la región de La Araucanía (Chile); en suelos de cenizas volcánicas. El modelo se contrastó con los existentes en la literatura, obteniendo la mejor precisión, el menor sesgo en cada fracción de altura, y la mayor eficiencia predictiva con un comportamiento gráfico flexible y estable en toda la longitud del fuste. La función de volumen obtenida de la integración numérica del modelo de ahusamiento, predice más de 99% del volumen del fuste sin corteza estimado mediante la fórmula de Smalian.Generalized taper model is presented for Eucalyptus nitens (Deane &amp; Maiden) Maiden. A non-linear model was fitted to data from 60 trees aged between 16 and 21 years, normal diameters between 11.5 and 52.0 cm, and with total heights between 47.49 and 12.27 m. Harvested in 6 stands located in 3 communes of The Araucania region (Chile), in volcanic ash soils. The model contract with existing models in the literature, obtaining better accuracy, the least bias in each fraction high, and the higher predictive efficiency with a flexible graphical behavior and stable over the entire length of the stem. The volume function obtained from the numerical integration of the taper model predicts over 99% of the variation in stem volume without bark estimated by formula Smalian.Fil: Rodriguez Toro, Andrés. Universidad de Concepción (Chile)Fil: Rubilar pons, Rafael. Universidad de Concepción (Chile)Fil: Muñoz Sáez, Fernando. Universidad de Concepción (Chile)Fil: Cártes Rodríguez, Eduardo. Universidad de Concepción (Chile)Fil: Acuña Carmona, Eduardo. Universidad de Concepción (Chile)Fil: Cancino Cancino, Jorge. Universidad de Concepción (Chile