HERBICIDES AND PLASTIC MULCH IN YAM (DIOSCOREA ALATA)

HERBICIDES AND PLASTIC MULCH IN YAM (DIOSCOREA ALATA

Caracterización del comportamiento mecánico del concreto simple con adición de fibras poliméricas recicladas PET

Trabajo de investigaciónReducir el impacto ambiental de la construcción, con la ayuda de materiales amigables con el medio ambiente. Las fibras de polímeros reciclables PET atienden a este llamado con la ayuda de estas se busca generar un concreto con propiedades mecánicas iguales o mejores a las del concreto convencional, promoviendo el desarrollo de las construcciones sostenibles y sustentables.RESUMEN INTRODUCCIÓN 1 GENERALIDADES 2 CARACTERIZACIÓN DE LOS MATERIALES 3 Diseño de mezcla 4 ELABORACIÓN DE MUESTRAS 5 ENSAYOS REALIZADOS 6 RESULTADOS OBTENIDOS 7 ANÁLISIS DE RESULTADOS 8 CONCLUSIONES Y RECOMENDACIONES 9 BIBLIOGRAFÍA 10 ANEXOSPregradoIngeniero Civi

Application of self-healing materials in architecture and construction industry: an exploratory review

ARTÍCULO ESPECIALIZADO EN REVISTA INTERNACIONAL INDEXADAThis work’s aim was to perform a review of the scientific literature from the standpoint of both the architect and builder. In the first place, on which self-healing materials are currently available for construction industry; secondly, to acknowledge the main applications and the self-healing methods of each material. The review was largely carried out using the scientific database tool sciencedirect® and other similar tools on the main applications of self-healing materials in construction industry. The results reveal that the main applications refer to the production of self-healing concretes and mortars by means of self-healing techniques, for example: insertion of microcapsules with various self-healing agents, followed by self-healing bacteria. It is concluded that with the use of these materials not only does the service life of structures of buildings improves, but also that of the entire building, increasing durability and noticeably decreasing maintenance and reparation costs

Manipulating Twitter Through Deletions

Research into influence campaigns on Twitter has mostly relied on identifying malicious activities from tweets obtained via public APIs. These APIs provide access to public tweets that have not been deleted. However, bad actors can delete content strategically to manipulate the system. Unfortunately, estimates based on publicly available Twitter data underestimate the true deletion volume. Here, we provide the first exhaustive, large-scale analysis of anomalous deletion patterns involving more than a billion deletions by over 11 million accounts. We find that a small fraction of accounts delete a large number of tweets daily. We also uncover two abusive behaviors that exploit deletions. First, limits on tweet volume are circumvented, allowing certain accounts to flood the network with over 26 thousand daily tweets. Second, coordinated networks of accounts engage in repetitive likes and unlikes of content that is eventually deleted, which can manipulate ranking algorithms. These kinds of abuse can be exploited to amplify content and inflate popularity, while evading detection. Our study provides platforms and researchers with new methods for identifying social media abuse

Contribution of research and development to the efficiency of social progress in latin america

Research and development, measured mainly by the production of patents, and by the investment of public expenditure in this sector, are recognized indicators that reflect the economic development of countries. This paper proposes to make a comparative analysis of the technical efficiency of some research and development factors in Latin American countries and their contribution to social progress. The data envelopment analysis method is applied to determine the comparative efficiency between countries and the contributions of inputs. As a result, the number of active researchers in the country and investment in research and development is the main inputs that contribute to maximizing social progress in Latin America

VaccinEU: COVID-19 Vaccine Conversations on Twitter in French, German and Italian.

Despite the increasing limitations for unvaccinated people, in many European countries there is still a non-negligible fraction of individuals who refuse to get vaccinated against SARS-CoV-2, undermining governmental efforts to eradicate the virus. We study the role of online social media in influencing individuals' opinion towards getting vaccinated by designing a large-scale collection of Twitter messages in three different languages -- French, German and Italian -- and providing public access to the data collected. Focusing on the European context, our VaccinEU dataset aims to help researchers to better understand the impact of online (mis)information about vaccines and design more accurate communication strategies to maximize vaccination coverage.Comment: 9 pages, 6 figures, 3 tables. Data can be fully accessed in a Dataverse (https://doi.org/10.7910/DVN/NZUMZG) and a GitHub repository (https://github.com/DataSciencePolimi/VaccinEU

Manejo de malezas durante y después del establecimiento de maní perenne.

A field study was conducted to evaluate the effect of dimethenamid and imazethapyr followed by clethodim and bromoxynil, on rhizoma perennial peanut (Arachis glabrata) during and after establishment.There were no significant differences in any of the parameters measured among rhizoma perennial peanut accessions as a result of the effects of herbicides. Excellent grass control was obtained when dimethenamid (preemergence) at 1.68 and 3.36 kg ai/ha was applied during the first month as compared with the use of imazethapyr. At 26 weeks after herbicide application (WAH) excellent grass control was obtained in all herbicide treatments. At 52 WAH no differences were observed for broadleaf and grass density. No differences were detected for dry weight of rhizoma perennial peanut and weeds among herbicide treatments at the 26- and 52-WAH harvests. Plots receiving imazethapyr as an early postemergence (POE) had 44 g/m2 more dry weight of weeds than plots with dimethenamid at the lowest rate, but no differences were found among the other treatments. The lowest weight of rhizoma perennial peanut was with imazethapyr early POE, as compared with the three other herbicide treatments. No difference was observed with dimethenamid at either rate. After two years, density of broadleaves was the highest (55.6 plants per square meter) with imazethapyr applied early POE. Density of grasses was lower with imazethapyr preemergence and dimethenamid at a lower rate than with the other two herbicide treatments. Overall, taking into account all rates and dates of herbicide applications, the best weed control was obtained with the early application dates. Se estableció un experimento de campo para evaluar el efecto de dimethenamid e imazethapyr seguido de clethodim y bromoxynil en maní perenne (Arachis glabrata), en y durante el establecimiento del mismo. No hubo diferencias significativas entre las variedades de maní perenne para el efecto de herbicida en ninguno de los parámetros medidos. Se obtuvo un excelente control de gramíneas con dimethenamid a 1.68 y 3.36 kg ¡a/ha el primer mes después de la aplicación en comparación con la aplicación de imazethapyr. A las 26 semanas después de la aplicación de los herbicidas se obtuvo excelente control de gramíneas con todos los tratamientos de herbicidas. A las 52 semanas después de la aplicación no hubo diferencias en la densidad de malezas de hoja ancha ni de gramíneas en ninguno de los tratamientos de herbicidas. No hubo diferencias en el peso seco del maní ni en el de malezas entre los tratamientos de herbicidas a las 26 y 52 semanas después de la aplicación. El peso seco de las malezas que recibieron imazethapyr postemergente temprano fue 44 g/m2 mayor que el de las malezas que recibieron dimethenamid a la dosis menor, pero no se observó diferencias entre los otros tratamientos. El menor rendimiento del maní perenne se obtuvo con la aplicación de imazethapyr postemergente temprano. Después de dos años de establecido, imazethapyr aplicado postemergente temprano produjo la mayor densidad de malezas de hoja ancha, con 55.6 plantas por metro cuadrado. La densidad de gramíneas fue menor con imazethapyr preemergente y con dimethenamid a la dosis de 1.68 kg ¡a/ha que con los otros dos tratamientos. En general, las aplicaciones de los herbicidas de forma preemergente resultaron en mayor rendimiento del maní perenne.

Influence of Aguamiel (Agave atrovirens) as a Natural Feed Additive on Cecal Fermentation Kinetics of Some Forage Species in Horse Feeding

The ability of the horse to efficiently utilize fiber and roughages due to the presence of fermentative microorganisms in their hindgut and the use of fibrous feeds as the main component of the mature horse diet have been documented [1,2]. Forages are important primary natural component of horse diet needed for normal function of their digestive system and to suppress certain metabolic disorders like hindgut acidosis, laminitis, and colic occasioned by feeding high-starch diets [3]This study aimed to evaluate the effect of different dose levels of aguamiel (Agave atrovirens) on in vitro cecal gas, methane (CH4), and carbon dioxide (CO2) productions of five forage species (Avena sativa [hay]), Moringa oleifera, Caesalpinia coriacea, Salix babylonica, and Eichhornia crassipes using inocula from the horse. The forage samples were incubated with three doses of aguamiel: 0, 34, and 68 mg of aguamiel/g dry matter (DM) of substrate. Cecal inocula were collected from four adult female Criolla horses (3–4 years of age and weighing 300 15.0 kg) grazed on native grasses for about 8 hours without supplementation. Forage type affected (P <.001) cecal asymptotic, rate and lag time of gas, CH4 and CO2 productions (mL/g DM), pH and DM degradability. Aguamiel dose had linear and quadratic effects (P < .05) on the asymptotic and rate of CH4 productions and rate and lag time of CO2 productions (mL/g DM). Forage type aguamiel dose interactions were significant (P < .05) for asymptotic, rate and lag time of gas, and CH4 and CO2 productions (mL/g DM). Forage species effects were pronounced (P < .05) on CH4 and CO2 productions (mL/g incubated and degraded DM) and proportional CH4 production at all hours of incubation, except for CO2 production (mL/g incubated DM). Aguamiel dose affected (P <.05) CO2 production (mL/g incubated DM) and proportional CO2 production at the incubated hours. Forage type aguamiel dose interactions were observed (P < .05) for CO2 production (mL/g incubated DM) and proportional CO2 production at the incubated hours but had no impact on CH4 production. It is concluded that addition of aguamiel to five forage species affected fermentation kinetics of gas production resulting in different in vitro cecal gas, CH4 and CO2 productions from these substrate

Niveles de razonamiento proporcional y micromundos. Un estudio en telesecundaria unitaria

[Objetivo] El razonamiento proporcional es un tipo de corriente compleja que implica reconocer comparaciones como la covariación entre magnitudes y comparaciones múltiples. El objetivo de este estudio fue analizar el razonamiento proporcional de alumnos de telesecundaria unitaria utilizando los niveles propuestos por Karplus (1983) a partir de un micromundo como GeoGebra. En el micromundo, el estudiantado puede explorar y construir significados sobre los objetos matemáticos. [Metodología] Se diseñaron cuatro actividades en GeoGebra, las cuales fueron aplicadas a 18 estudiantes de una telesecundaria unitaria (modalidad educativa en México). [Resultados] Se identificó que los participantes están en niveles iniciales, que responden a estructuras aditivas, cualitativas o erróneas para justificar sus procedimientos. Los niveles más complejos de razonamiento proporcional relacionados con el uso de razones y constantes de proporcionalidad se obtuvieron cuando el estudiantado interactuaba con sus pares y con el micromundo. Los niveles de razonamiento no son mutuamente excluyentes, debido a que el alumnado puede razonar de diferente manera según la situación y las posibilidades del software. [Conclusiones] El uso de micromundos en la exploración del razonamiento proporcional posibilita acciones que no pueden llevarse a cabo en “lápiz y papel”, lo cual brinda la oportunidad de interactuar con construcciones en movimiento, además genera interacciones de reforzamiento o construcción de saberes desarrollados en conjunto