Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

Background. The study area exhibits a first class catena having homogenous parent material and forming a spatial continuum. Functionally and taxonomically distinct soils result from differences in drainage and lateral movement of materials in the soil. Objective. To classify the soils using a geopedological approach which involves a strong relationship between pedology and geomorphology. Methodology. The area was delineated into Soil Mapping Units (SMUs) through augering into soils defined by different macro-relief. Mapping units were demarcated according to slope categories namely 0 to 5%, 5 to 8%, 8 to 16%, 16 to 30% and >30% connoted as flat to gently undulating (AB), undulating (C), rolling (D), moderately steep (E) and steep (F) respectively. Profile pits were dug in the five identified mapping units using Stratified Random Sampling technique. Identified SMUs include UmIr/F, UmIr/E, UxIr/D, UxIr/C and UxIr/AB in the order of decreasing slope gradient. The first entry represents the physiographic unit (Uplands, U), followed by physiographic position (lower middle uplands, m or uplands, undifferentiated levels, x), geology (I), color (r) and slope class respectively. A soil map with a legend describing the mapping units was produced using a scale of 1:10000. Topographic influence on soil properties was presented by Pearson’s correlation coefficient (r) with p-value included where the influence was significant. Statistical analysis was done using IBM SPSS 25th edition and MS Excel. Results. All the mapping units are well drained and deep to very deep (>80 cm). The color of the upper B horizon is predominantly dark reddish brown. The texture of top horizon is clay in UmIr/F and UmIr/E and is clay loam to clay, sandy clay loam to clay and loam to clay loam in UxIr/D, UxIr/C and UxIr/AB respectively, lucidly exposing the influence of topography on the depth of clay illuviation (clay: r = 0.724; p ≤ 0.01). The structure is predominantly subangular blocky throughout the profiles with the top horizon of cultivated areas having predominantly granular structure. Saturated hydraulic conductivity (Ksat) generally decreases with increasing clay content down the profiles and the bulk density ranges from 0.9 to 1.2gcm-3. Means of soil reaction of top horizons generally slightly decrease with decreasing gradient (r = 0.231) having lower values in cultivated areas. Percent organic carbon regularly decreases down the profiles with higher values in uncultivated, steeper areas (r = 0.521; p ≤ 0.05). In the top horizon: Total nitrogen is predominantly medium across the study area ranging from 0.2 to 0.56% (r = 0.185) and follows the organic carbon trend; Available phosphorus is deficient (<20 ppm) in the study area. Bases are sufficiently to richly supplied while micronutrients are richly supplied. All soils are non-saline and non-sodic; the cation exchange capacity (CEC) soil is predominantly medium across the profiles ranging from 15 to 27.6 cmol(+)/kg with values increasing slightly with increasing slope (r = 0.320). Based on data collected from description of the profiles and physicochemical data of the soils and according to IUSS Working Group WRB (2014) soil classification legend, the soils were classified as Mollic Nitisols. Implications. The soils are generally fertile for crop production but organic manure is recommended to buffer the acidic soil reaction, improve nitrogen and phosphorus sources. Conclusion. Soil characterization, land evaluation and precise input application are encouraged.

Background. From the early days, human beings have used plants to satisfy their biological or cultural needs; this man-plant relationship is studied by ethnobotany. Pumpkins were one of the first plants domesticated by Homo sapiens and currently they are important species in human diet. Objective. To explore the knowledge about the relationship that exists between farmers and pumpkin species cultivated in Nayarit, Mexico. Methodology. Consisted of fieldwork in the years 2013 and 2014, where 15 municipalities were visited, and 35 farmers were interviewed; techniques used for the compilation of information were through semi-structured interviews and the participant observation method. Species studied were Cucurbita argyrosperma Huber, Cucurbita ficifolia Bouché, Cucurbita pepo L. and Cucurbita moschata Duch. Ex Lam. Information collected included the traditional classification, uses, selection criteria for seed, a source of knowledge acquisition of the crop and beliefs and rites related to the species. Results. Main use of pumpkin among farmers were as food, forage and medicine. Seeds and fruits were the main elements of interest; producers’ criteria for selection of plants are based on the characteristics of fruits using established patterns, with which they create their selections for fruit or seed production. Conclusion. It was found that Cucurbita spp. have a ritualistic relationship with the Huichol ethnic group, as it is part of their ceremonies related to their beliefs.

Antecedentes. La tilapia del Nilo (Oreochromis niloticus) es una de las especies más importantes en la acuicultura a nivel mundial; sin embargo, el uso de esteroides para masculinizar grandes volúmenes de alevines es visto negativamente por el mercado y por grupos medioambientales. El uso de la progenie de machos YY es una alternativa reciente que, en teoría, permite mantener los mismos rendimientos, con la ventaja de comercializar un producto libre de hormonas. Objetivo. Evaluar bajo condiciones comerciales de cultivo el desempeño productivo, el índice gonadosomático, la composición bioquímica, así como el porcentaje de machos obtenido en la progenie de machos YY y compararlos contra los de una progenie masculinizada comercialmente con flouximesterona. Metodología. Se sembraron, juveniles producidos a partir de un macho YY y juveniles masculinizados en estanques exteriores de 3 m2 (por triplicado), se cultivaron durante 105 días y se alimentaron siguiendo un protocolo de alimentación tipo comercial. Resultados. No se detectaron diferencias significativas entre ambas progenies con respecto al desempeño productivo durante el crecimiento, incluyendo el rendimiento del filete. Sin embargo, la progenie de machos YY mostró valores significativamente más altos (P < 0.05) de humedad, ceniza y lípidos en músculo, así como de índice gonadosomático, esto último, probablemente debido a la presencia de un pequeño porcentaje de hembras (8%). Implicaciones. El estudio contribuye a la inserción de la tecnología YY al cultivo comercial de tilapia del Nilo. Conclusión. El desempeño mostrado por la progenie de machos YY en comparación contra el de una línea masculinizada es similar en términos de crecimiento, rendimiento y supervivencia; por lo que su implementación en la región podría disminuir el costo de producción y reducir la contaminación del medio ambiente, gracias a la reducción en el uso de hormonas. 

Background. Ticks are one of the main threats that affect cattle production in Mexico. In the ecosystems, these parasites are naturally regulated by microorganisms such as entomopathogenic fungi (EPF) and bacteria, wich are capable of causing them disease and death. However, some studies mention that the effects of climate change and wrong practices in the management of grasslands, trees and animals affect the distribution of these beneficial organisms in the livestock areas of Mexican tropic. Objectives. 1) To determine the distribution of EPF in cattle farm soils from the Mexican Tropics, 2) to identify the sites within the cattle farms with greatest presence and richness of EPF and 3) to identify factors associated with their presence. Methodology. Soil samples of seventy-two cattle farms from twelve municipalities of Veracruz, México, with high prevalence of ectoparasites, were collected. Galleria mellonella larvae were used as bait in order to isolate EPF from soils; then, fungi were identified by molecular methods. Results. Four genera of EPF were isolated and M. anisopliae was the most prevalent. Live fences soils showed the greatest EPF richness. The mountainous region (OR=2.25), cattle farm altitude (401-600 meters above sea level) (OR=3.81) and cattle farms where they do not use herbicides (OR=3.66) are factors associated to the presence of EPF in cattle farms soils (P < 0.05). Implications. Information about distribution and diversity of EPF, as well as the knowledge of factors that may affect them, will help to understand their importance as natural regulators of pests in cattle farms, to regulate agronomic activities to optimize their survival and help to design strategies for isolation of native EPF with potential bio-regulatory effects of ectoparasites. Conclusions. The isolation and richness of EPF in soils destined for the production of grazing cattle where Metarhizium anisopliae was the most isolated is reported for the first time in Mexico. The live fences soils presented the greatest wealth of EPF and some management and geographic characteristics were identified as factors associated with the fungal presence.

Antecedentes. La selección de las mejores zonas agroclimáticas es de importancia significativa para el desarrollo agropecuario, rural y forestal de la entidad, debido principalmente a que los habitantes y actores locales del estado Carabobo ya pueden contar con un estudio que les indica los lugares para producir sus alimentos, utilizarlos al máximo y de la mejor manera. Objetivo. Analizar e interpretar la aptitud de las tierras agrícolas en Carabobo a través de técnicas multivariantes. Metodología. Se utilizaron los datos de superficie (Km2) para las fechas de siembre de mayo- agosto de cuatro cultivos estratégicos: maíz, cebolla, tomate y papa. Se aplicó el Análisis de Componentes Principales (ACP), Análisis Discriminante mediante la Regresión de Mínimos Cuadrados Parciales (PLSDA) y el Análisis de Conglomerados Jerárquico. Resultados. Mediante el ACP se seleccionaron los primeros dos componentes que explicaban el 67.6 % de la variación total. Esto permitió una clasificación de los municipios con mayor superficie apta de cultivos en función de la fecha de siembra, discriminando con mayor incidencia la superficie apta para maíz de los municipios Libertador, Carlos Arvelo, Valencia y Naguanagua, cuya fecha idónea de siembra se establecería del 11-20 de mayo. Conclusión. El método multivariado del ACP empleado representó una herramienta para describir y caracterizar la diversidad de los rubros estudiados en la agricultura de Carabobo cuyos resultados pudieran ser la base para estrategias de desarrollo agrícola.

Background. With ever-increasing populace pressure and rapid depletion of natural resources, it has become exceptionally important to diversify the present time agriculture with the cultivation of some wild varieties of tubers, rhizomes and corms in order to meet various human nutrient needs. However, information regarding the nutritional and antinutritional composition is meager. Objective. To study the chemical composition and antinutritional factors of the wild edible corms, rhizomes and tubers consumed by the Palliyars and Kanikkar tribes living in South Eastern Slopes of Western Ghats, Tamil Nadu Methodology. The wild edible corms of Alocasia macrorrhiza, Amorphophallus paeoniifolius var campanulatus, Amorphophallus sylvaticus, Colocasia esculenta, Xanthosoma sagittifolium, Xanthosoma violaceum, rhizomes of Canna indica, Maranta arundinacea and tubers of Asparagus racemosus, Nymphaea pubescens and Nymphaea rubra were analysed for proximate and mineral composition, starch, vitamins like niacin, ascorbic acid and antinutritional factors like total free phenolics, tannins, hydrogen cyanide, total oxalate, amylase and trypsin inhibitor activities were quantified. Also, in vitro protein and starch digestibility were assessed. Results. The rhizome of Maranta arundinacea and tubers of Nymphaea pubescens contain high quantity of crude proteins. The tubers of Asparagus racemosus contained higher amount of crude lipids. The corms of Alocasia macrorrhiza, Colocasia esculenta, Xanthosoma sagittifolium and Xanthosoma violaceum appeared to have a higher level of potassium content compared to recommended Dietary allowances (RDA) for infants, children and adults. The corms of Alocasia macrorrhiza, Amorphophallus sylvaticus, Xanthosoma violaceum and rhizomes of Maranta arundinacea were found to contain more starch. All the investigated samples had low in vitro protein digestibility. Implications. The present result highlights the potentiality of these underground plant parts as source of unconventional foods. Being wild, they also are easily accessible and cheaper. Studies on nutritional value of wild plant food are of extensive importance since it may help to recognize long forgotten food resources. Conclusion. Most of the wild edible corms, rhizomes and tubers were found to be a good source of protein, lipid, total dietary fiber, starch, vitamins and minerals. All the investigated samples exhibited variations in the levels of the total free phenolics, tannins, hydrogen cyanide, total oxalate, amylase and trypsin inhibitors

Background. Taro (Colocasia esculenta L. Schott) is an economical import crop in Actopan, Veracruz, since it is exported to the United States of America (USA) and Canada. In Mexico, there is no regulation to implement traceability systems in agricultural products. Objective. To propose a traceability system in the supply chain of taro produced in Veracruz. Methodology. A questionnaire was designed to obtain information related to the production process; a second questionnaire asked about the packaging information; twenty-four producers and eight packinghouse managers were interviewed. Results and discussion. Producers have been growing taro for 10 years, they do not have any specific planting season and grow the variety Coco. No soil analysis is performed, irrigation is by flooding and the main pest is the mouse (Apodemus sylvaticus). Each producer makes an agreement with a packing house; the company performs the harvesting and then the packaging process. Wooden pallets are used for packaging; each pallet piles up 60 sacks of 18 kg of taro. Implications. The traceability model for the Mexican taro could be adapted to the traditional way of production in Mexico to increase competitiveness. Conclusions. The shipping label contains scarce information about the origin of the product. Links of the supply chain were identified and a traceability model for taro is proposed for first time.

This paper presents a comparative analysis of the studies of Juan Larrea and Eugenio F. Granell on Picasso's Guernica. Despite the personal psychological projections and divergent aesthetic transits of the two authors, the analyzed works present analogous hermeneutical keys: the common experience of the American exile —tinged with nostalgia, frustration and hope—; the militant use of the painting, perceptible in the historical-symbolic and mythical interpretation of the painting, and the apocalyptic and, however, hopeful and utopian vision. The essays carried out by those authors on the Picassian painting not only constitute critical-literary ekphrasis in the aforementioned paths, but also literary ekphrasis, verbal tables, in which the imaginative cognition of both authors is manifested with their own profiles, facing the enigmas and silences of Guernica.

The idea that singer-songwriters can be considered poets has been defended by many people and found its culmination when the Swedish Academy awarded the Nobel Prize in Literature to Bob Dylan in 2016. This paper reviews this idea considering the different stages of evolution of lyric poetry and contrasting them with the creative activity carried out by singer-songwriters. The objective pursued is to show what convergences and divergences really exist between the figure of a singer-songwriter and that of a poet.

I am dealing in these pages with a curious sample of the multifaceted relationships between the fields of theater and cinema. Filmmaker Orson Welles stars in a stage biography written by American playwright Richard France. This theatrical piece is the subject of a staging directed by Esteve Riambau, who, in turn, directs a documentary film that narrates the various phases of the process to transfer the text to the stage and where a corpus of theoretical reflections on this process by the leading actor (José M.ª Pou) and of other people involved in it, including the author himself. The theatrical text, its staging (with the variants introduced by its manager) and the cinematographic documentary around it are successively analyzed.