El presente trabajo se inscribe dentro del campo de estudios sobre la historia del movimiento estudiantil reformista durante los años 60 y 70 en la Argentina y tiene como propósito más específico la elaboración de un mapa de la conflictividad del movimiento estudiantil desarrollada entre los años 1969-1972, en una región en particular: la ciudad de La Plata. Dicho mapa de la conflictividad se realizará por medio de un estudio cuantitativo, confeccionado a partir fuentes hemerográficas. Las variables que se analizaran serán las siguientes: la intensidad y masividad que evidenciaron los conflictos; los distintos sectores y actores que al interior del movimiento estudiantil presentaron un mayor protagonismo; los reclamos y demandas que motorizaron las luchas; las formas y características que adquirieron las acciones motorizadas por los estudiantes, como así también los vínculos y alianzas que establecieron con el movimiento obrero y con otros sectores sociales. Las tendencias divisadas en la conflictividad estudiantil serán puestas en tensión con las encontradas para el caso en particular del movimiento obrero del Gran La Plata, que hemos analizado en otros trabajos, lo que nos permitirá no solo contrastar sino también apreciar con mayor precisión las particularidades que presentó la conflictividad del movimiento estudiantil reformista platense. La finalidad de dicho análisis es poder tanto complejizar y matizar algunas lecturas e interpretaciones generales sobre el periodo en particular, como profundizar sobre varias temáticas y dimensiones que hacen a las características y dinámica que presentó el movimiento estudiantil durante las décadas del sesenta y setenta.

Introduction:The leaves have been extensively investigated in the biology activity in human and animal health, where important metabolites such as phenols have been associated, of which the following stand out: flavonoids, tannins among other compounds, however this document aims to locate the anatomical location and analyze the content of major flavonoids in the mature and immature guava leaf.The study was complemented with the analysis of the ethyl ether and butanol extracts; The two types of leaves with their respective extracts were analyzed by thin layer chromatography, which allowed them to be detected and their concentration estimated by liquid chromatography.The study indicated that the mature leaf shows a large amount of flavonoids located in the adaxial and abaxial epidermis, as well as in glands, while in the immature leaf in the adaxial epidermis and in the abaxial epidermis it only presented a minimal proportion of them. Conclusion: Total flavonoid concentrations range from 2610 mg *kg-1 in the mature leaf to 2016 mg* kg-1 for the immature leaf, quercetin being the one that was found and observed in the highest proportion in both leaves.

In two contrasting agricultural ecohabitats (agrohabitats) in the avocado production area in the municipality of Cuernavaca, Morelos, an analysis of nutrimental status, soil fertility and water quality was conducted to measure soil fertility levels and to determine the nutrimental state of the trees. The "Hass" variety avocado groves studied had an average age of 8 years; the first grove was planted in an acrisol soil (1700 to 1900 meters above mean sea level [mamsl]); the second, in an andosol soil (1200 to 1700 mamsl). In each agrohabitat, tests were performed to determine the soil's physical and chemical characteristics. The physical and chemical characteristics of the soils of this zone differ as do the nutrimental states of the avocado trees in the two agrohabitats. The trees showed excessive concentration of Ca, Fe, S, Z and Mg. The indices of Deviation from Optimal Percentage (DOP) in the two agrohabitats showed different nutrimental requirements; nevertheless, they were low and very near to zero, 14.218 and 13.350 respectively. The water used for the agricultural irrigation was low in salinity and sodium content and thus may be used for the agricultural irrigation without restrictions.

¿Es posible protestar bajo una pandemia cuando existen reglas y razones para el aislamiento? Pero también, ¿es posible no protestar durante la pandemia cuando esta profundizó una crisis de dimensiones inéditas? Este trabajo presenta una descripción y un análisis de las tendencias efectivasen Argentina entre 2019 y Julio de 2020.

In the Mexican tropics the guava trees can grow and produce in any season, so they can be harvested out of the period of high competition marketing (Summer). It studied the growth kinetics of leaves and fruits of guava trees at the dry tropical conditions of the State of Guerrero, in guava trees of four years old and was evaluated a non-destructive method for measuring leaf area from November to May. 100 sheets of 10 randomly selected trees were cut. It was found that leaf length X the width X 0.72581647 (conversion factor) gave an estimated leaf area which was significantly correlated with that obtained by the integrator of leaf area. Both in length and width the leaf growth kinetics were sigmoid with three growth stages: In Stage I (15 days) leaves grew 21.2% and 21.5%; in Stage II (26 days) grew 73.6% and 68%; and in Stage III (30 days). They Increased 5.2% and 10.5% in the primary and secondary sprouts. The fruit growth in its equatorial and polar diameters corresponded to a double sigmoid kinetics. In Stage I (61 days) it reached 1.9 and 2.3 cm; in Stage II (62-102 days) it reached 3.09 and 3.62 cm; and in Stage III (103 to 126 days) it reached 4.63 and 5.13 cm, as well as the physiological maturity of fruit.