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

Background: Globally, more than 40% of annual food production comes from irrigated lands, and agriculture is the largest consumer of water, at 70% of all freshwater withdrawals. As water scarcity becomes more acute worldwide, increasing the effectiveness of agricultural water resources becomes a priority for enhanced food production. Methodology: A study was carried out for two seasons in Kiboko, Makindu Sub-County during 2018 and 2019 short and long rains, respectively to evaluate the response of maize growth, yield, and water use efficiency to deficit irrigation in the semi-arid area. The experiment was arranged in Randomized Complete Block Design with three replicates. The irrigation regimes were T1 (100 % field capacity), T2 (75 % field capacity, T3 (50% field capacity), T4 (25 % field capacity), and T5 (rain-fed) were evaluated. Results: In season I, there was a difference (P≤0.05) on Plant height, leaf area, and leaf area index, in T1 compared to T5. Plants in T1 were higher (308.1cm) than those in T5 (263cm) (control). Irrigation deficit showed an effect (P≤0.05) on maize growth in season II, with plant height of 270.3cm in T1 compared to 95.6cm in T5. The yield components showed a difference (P≤0.05) on cob-size, 100grains weight, aboveground biomass and harvest index in both seasons. The highest yield of 10.9 and 10.2 t ha-1 was obtained in T1in Season I and II, respectively and lowest in T5 (8.8 t ha-1 and 3.0 t ha-1) in the season I and season II, respectively. Higher aboveground biomass and yield were obtained under full irrigation, and declined under varied deficit irrigation regimes. Water use efficiency had no significant difference at the different treatments in the season I, since rains were moderately reliable, thus allowing pausing of irrigation with little water stress. However, in season II, a difference (P≤0.05) in water use efficiency (WUE) was observed. Generally, water use efficiency ranged from 19.6 to 22.kg ha-1 mm-1 in season I and 16.6 to 24.8 kg ha-1mm-1 in season II. Implication: Irrigating maize at 50% water deficit increases the WUE with minimal yield decline, hence a better deficit irrigation strategy in water conservation under scarcity situation. Conclusion: Growth and yield of maize increased with increased amount of irrigation water and decreased under reduced irrigation while WUE increased with reduced irrigation and decreased under sever water stress. 

Antecedentes. El cultivo de pastos forrajeros es un componente importante en el sistema de producción bovina de doble propósito; sin embargo, existen insectos plaga que pueden disminuir los rendimientos de la biomasa. Objetivo. Identificar taxonómicamente al agente causal que causo daño a los cultivares Panicum maximum (Jacq.) cv. Mombasa y Panicum maximum cv. Zuri. Metodología. En dos localidades de la región centro de Veracruz, se realizaron recolectas de un insecto en los estadios de larva y pupa, con el método del cuadrante en una superficie de 50 ha. Posteriormente en el laboratorio las larvas se hirvieron durante dos minutos y se preservaron en alcohol al 70%, las pupas se colocaron en una cámara de cría con follaje para obtener adultos y poder extraer sus genitalias, que es la estructura morfológica más importante para la identificación a especie. Resultados. Se recolectaron 650 larvas y 65 pupas, de estas últimas todas llegaron al estado adulto, con base en la morfología taxonómica se determinó la especie Mocis latipes o falso medidor. También de manera cualitativa se observó aproximadamente un daño del 40% en el follaje del total de plantas por ha. Implicaciones. Una correcta identificación del insecto plaga permite la implementación de una estrategia para su manejo adecuado. Conclusión. Se identificó la especie M. latipes, en pastos forrajeros P. maximum cv. Mombasa y P. maximum cv. Zuri en Veracruz.

The analysis of this poem by Justo Alejo lead us to reflect on experimental poetry and art in general throughout the second half of the 20th century. Aesthetics and philosophical contributions show a drastric change in the way art and life itself are conceived but, above all, they provide a peculiar way to understand reality. The smallest detail of daily life is an excuse for the poet to exercise a harsh social criticism as well as a warning. The poet makes use of typical resources from both advertising and avant-garde literature in order to build a speech where the word and the image come together, feed each other and build together new horizons. In the aesthetic regime of art, montage is essential because it installs a new concept of temporality, whose basic element is simultaneity; it introduces an operation that breaks the logic based on the supremacy of text over image and establishes another type of relationship that defines as interface, where there is a constant link in a double community between the signs and us. Now that forty-two years have passed since the author died, this article would like to pay him a small tribute by highlighting the profound validity of his thinking and the modernity of his poetry.

In late-francoist Spain, two were the disputes over the significance of the term «avant-garde»: the one sprung by the publication of Castellet’s Nueve novísimos poetas españoles (1970) and that (1973) which confront Antoni Tàpies with the Grup de Treball. Even though Tàpies and Castellet were talking, one in the name of painting, and the other, in the name of poetry, both were defending a formalist conception of the avant-garde, whose transgressive character consist in the bare exposition of the limitations of its medium. Both the poets that criticize Castellet’s anthology and the Grup de Treball were defending a concept of the avant-garde which rejects the principle of art’s autonomy. They propose new ways of integrating aesthetic experience in social life. From a comparative standpoint, I will describe the aesthetic and political similarities between Castellet’s and Tàpies’ stances, as much as the success of their conception of the avant-garde.

This work analyzes the way in which the cinematographic references are manifested in Leopoldo María Panero's poetry book Así se fundó Carnaby Street. This book is often linked to the literary production of the poetic groups known as the "Novísimso" or the "generación del 68", in the middle of the mass media boom and the beginning of the Spanish transition. For such reason, in this article, we try to classify the way in which those film references appear in the poetry book, base on typology and with the help of Rajewsky's theories about intermediality. In addition, as we justify the groups that we consider relevant for our classification, we will analyze some poems through this intermediality.

Background. Increasing atmospheric concentrations of methane (CH4) have led scientists to examine its sources of origin. Mitigation of enteric CH4 production by ruminants has been recognized as an important goal because it reduces greenhouse gas emission and improves feed efficiency. Objective. The study evaluated the chemical composition and its relationship with in vitro total gas (GP24) and in vitro methane (CH4) production parameters of five tropical wild legume seeds [(Luffa cylindrica (LC), Piliostigma thonningii (PT), Detarium microcarpum (DM), Daniellia oliveri (DO) and Afzelia africana (AA)]. Methodology. Chemical compositions were analysed, while total GP volume was measured and CH4 estimated after 24 h incubation. Results. Total GP24 produced by the seeds steadily increased and was most pronounced (P<0.05) in AA seed meal (64.71 mL/200 mg DM), and the least in LC (37.83 mL/200 mg DM). CH4 concentration (MC) varied (P<0.05) from 9.90 in AA to 23.93 in LC. Methane reduction potential (MRP) was higher (P<0.05) for AA seed meal and lowest for LC. There were positive correlations (r = 0.685**, r = 0.763* respectively) between crude protein and non-fibre carbohydrates (NFC) contents of the seeds and total gas production at 24 h incubation. Fibre fractions (NDF and ADF) were positively, (r = 0.978 and r = 0.874 respectively) correlated with MC, and negatively (r = - 0.927 and r = - 0.870, respectively) associated with total GP24 and MRP. CP, EE and NFC had a more pronounced positive correlation (r = 0.948**, r = 0.851** and r = 0.852** respectively) with MRP. Implication. Results suggest that all the selected seeds have the potential to reduce methane production and positively impact rumen fermentation. Conclusion. Seed containing more nutrients (CP, EE, and NFC) reduced enteric methane production more than any other of the chemical components in the study.

Antecedentes: Actualmente existe una creciente demanda de híbridos de Phalaenopsis sp., por lo cual es necesario desarrollar protocolos de propagación masiva que aseguren altos porcentajes de regeneración clonal tal como la técnica de embriogénesis somática. Así mismo, estudiar la variación genética dentro de las plantas regeneradas ofrece un mayor conocimiento de los alcances del protocolo de micropropagación en relación a la estabilidad genética de los materiales empleados. Objetivo: En el presente trabajo de investigación se evaluó la combinación de tres concentraciones y dos tipos de reguladores de crecimiento vegetal (RCV), la citocinina bencilaminopurina (BA) (1.0, 2.0 y 3.0 mgL-1) en combinación con tres concentraciones de ácido 2,4-diclorofenoxiacético (2,4-D) (3.0, 4.0 y 5.0 mgL-1), para la inducción de embriones somáticos, además, se analizó la estabilidad genética de las plántulas regeneradas mediante marcadores moleculares tipo RAPD (Random Amplified Polymorphic DNA, por sus siglas en inglés). Metodología: La embriogénesis somática se indujo a partir de explantes de hoja con distintos grados de desarrollo: primera hoja se consideró como explante maduro (PH) y la tercera hoja como explante joven (TH), obtenidas de una plántula de Phalaenopsis sp. var. Dudú cultivadas in vitro, de 15-20 cm de altura. Resultados: El mayor número de plantas regeneradas fue de 29.8 a los 135 días después de iniciado el cultivo (ddic) con 2.0 y 5.0 mgL-1 de BA y 2,4-D, respectivamente, utilizando como explante la TH en la respuesta morfogenética de los explantes regenerados, se observó una correlación entre la edad del explante y la concentración de RCV. El análisis de la variación genética mostró cambios en los patrones de bandeo, observando bandas polimórficas con los cuatro iniciadores utilizados, aludiendo variación somaclonal en las plantas regeneradas. Implicaciones: Los resultados obtenidos aportan una alternativa de regeneración, además de ofrecer una metodología para iniciar programas de mejoramiento genético en Phalaenopsis sp. var. Dudú. Conclusiones: Se logró la regeneración in vitro de Phalaenopsis sp. var. Dudú mediante embriogénesis somática, así como la detección de cambios genéticos en el material regenerado.

Background: Phosphorous is a limiting crop nutrient in highly weathered tropical soils due to fixation, and its availability for plants’ uptake is influenced by soil physico-chemical characterics, land use type and management practices.    Objective: To evaluate the relationship between selected physico-chemical properties and phosphorous sorption characteristics of a humic nitisol (Alfisol) from Tigoni, Kiambu County, central Kenya. Methodology: The soil was sampled from the same area with different land uses that include tea plantation, maize field and natural forest at 0-25, 25-50 and 50-75 cm depths.  P solution at the rates of 50, 100, 150, 200 mg P L−1 in a 24 h contact time were used in the study for maximum sorption. The data was analysed by simple regression and Pearson correlation analysis.  Results: The adsorption data was fitted more to Langmuir model (R2 = 0.9100-0.9994) compared to Freundlich (R2 = 0.6815-0.9971). The values of P sorption maxima ( ) determined by Langmuir model ranged from 3,333-5,000 mg kg-1 and bonding energies ( ) ranged from 0.2308-1.5385 L mg-1. The buffering capacity of soil ranged from 769-5000 L kg-1 and the external P requirement at 0.2 mg kg-1 (  ranged from 147-1176 mg P kg-1 both increasing with soil depth. P sorption maxima were negatively and significantly correlated with organic carbon (r2 = -0.700*) and Ca2+ (r2 = -0.703*) contents. The pH of soil and clay content were negatively correlated with adsorption parameters ( ) while Al content was positively correlated though none of them was statistically significant. Implication: The data revealed a highly P-sorbing soil particularly tea plantation, a situation that can be alleviated by management practices such as liming and enhancing soil organic matter content. Field experiments are however, recommended to validate the findings of this study. Conclusion: Land use type influences P-sorption capacity of soil hence, fertilizer recommendations should be based on soil physico-chemical characteristics besides crop nutrient requirements.

Antecedentes. Los ambientes ribereños ofrecen microhábitats que pueden servir como lugar de desarrollo y vías de desplazamiento para diversas especies de reptiles, sin embargo, estas especies se encuentran amenazadas por la pérdida del hábitat, tráfico ilegal, uso y persecución por el hombre, entre otras. Objetivo. Analizar la diversidad y estado de conservación de la comunidad de reptiles asociados a dos ecosistemas ribereños del estado de Tabasco. Metodología. El estudio se realizó en los márgenes del arroyo del ejido Villa de Guadalupe ubicado dentro del complejo Ecoturístico Agua Selva del municipio de Huimanguillo, Tabasco, México. Para el registro de los individuos se establecieron diez transectos de banda en los márgenes del arroyo de 100 m de largo por 10 m de ancho, separados por 25 m entre ellos, cinco transectos ubicados en vegetación primaria (VP) y cinco en vegetación secundaria (VS), los cuales fueron muestreados mensualmente durante un año con el método de encuentros visuales (VES), con recorridos diurnos y nocturnos. Resultados. Se registró un total de 391 individuos de 25 especies, de las cuales 13 fueron lagartijas y 12 serpientes. Las especies Tantilla rubra, Geophis carinosus y Lepidophyma tuxtlae son nuevos registros para el estado de Tabasco. El índice de diversidad (1D) mostró que las lagartijas fueron más diversas en VP que en VS (5.16 y 3.59) y que las serpientes fueron más diversas en VS que en VP (6.15 y 4.41). Así mismo, se determinó que el 36 % de los reptiles se encuentran dentro de alguna categoría de protección de acuerdo a la NOM-059-SEMARNAT-2010 y 92 % en categorías de la IUCN y del EVS. Implicaciones. Los resultados de la presente investigación resaltan la importancia de los ecosistemas ribereños en el resguardo y mantenimiento de los reptiles, de igual manera se sugiere utilizar el EVS como un método complementario para evaluar el estado de conservación de las especies y enriquecer la información proporcionada por NOM-059-SEMARNAT-2010 y la IUCN.