Efecto del uso del suelo en las formas y disponibilidad de fósforo de un Andisol de la Meseta P’urhépecha, Michoacán

Los Andisoles se distinguen por su habilidad para retener fósforo (P), lo cual restringe la productividad agrícola. Se planteó la hipótesis que la disponibilidad de P en las diferentes formas extraídas secuencialmente, variaría de acuerdo al uso del suelo y su intercambio dependería de las características químicas del mismo. En este estudio, se usaron los métodos de extracción secuencial y dilución isotópica para evaluar el efecto del uso del suelo y la adición de fertilizante en las fracciones inorgánicas y orgánicas de P y su disponibilidad. Se incluyeron muestras de suelo de un sitio con una larga historia de fertilización y otro de una área adyacente de bosque nativo, al cual se les aplicó KH232PO4. El suelo se fraccionó secuencialmente después de un periodo de 49 días de incubación y se determinó la proporción (%) de 32P recuperado en cada fracción. En todas las fracciones se recuperó 32P, lo que demuestra la existencia de intercambio entre el 32P y P natural del suelo. Las reacciones de intercambio ocurrieron mayormente en las fracciones inorgánicas. Las fracciones de resina-Pi, NaHCO3-Pi e NaOH0.1-Pi aumentaron con la fertilización de P, siendo la fracción de NaOH0.1-Pi, la mayor fuente del nutriente. El mayor incremento de 32P recuperado en la fracción de NaOH0.1-Pi, indica que el P añadido y transformado en esta fracción es altamente intercambiable y contribuye con la fertilidad de este suelo. Las fracciones recalcitrantes presentaron poco P intercambiable. En contraste, en el suelo de bosque sin fertilizar, más del 20% del 32P se recuperó en las fracciones de Bic-Po y NaOH-Po, 49 días después de que se añadió el radiotrazador. La transformación de las fracciones de P fue dependiente del tipo de suelo y la adición de P. El P aplicado permaneció, preferiblemente, en la forma que puede ser intercambiable con la solución del suelo y, por consiguiente, puede estar disponible para la planta

Chía (Salvia hispanica L.) situación actual y tendencias futuras

La chía es un grano apreciado por su gran contenido de ácidos grasos, entre ellos el omega 3 útil para contrarrestar los triglicéridos, de igual manera se relaciona con la pérdida de peso en el ser humano, en tiempos prehispánicos se requería como pago de tributo a los pueblos conquistadores, las semillas se usaban como revitalizante para los combatientes que partían a la guerra y para las mujeres que se preparaban para el parto, actualmente su uso es común en la preparación de agua fresca, en preparación de pintura (aceite) y como enriquecedor de productos panificados. La producción se perdió a raíz de la conquista ya que los españoles trajeron nuevos cultivos, los cuales fueron desplazando a la chía a sembrase en zonas muy apartadas. Hoy la chía ha tenido un repunte gracias a sus propiedades, las cuales han permitido ampliar su consumo. Siendo México lugar de origen, se cuenta las condiciones propicias para el desarrollo solo hay que buscar los mejores lugares y las practicas apropiadas para tener éxito en el l cultivo. Teniendo en cuenta lo antes expuesto se realizó una revisión bibliográfica, siendo el objetivo del presente trabajo dar a conocer las tendencias futuras y actuales de la chía

Dosimetry and radio-stimulation in mesquite (Neltuma laevigata W.) seeds

Objective: The research focused on a germination response in Mezquite (Neltuma laevigata) using gamma radiation (Cobalt 60) at different doses aiming to obtain a greater germination response than a non-irradiated seed. Design/methodology/approach: The seeds had different collection times and identities, a lot from Durango (10 years) and other from Hidalgo (2 months). Both lots were exposed to sixteen different doses of gamma radiation, having a control (non irradiated). Seeds were subsequently subjected to in vitro conditions using Murashige and Skoog medium. They were monitored daily for a period of two weeks to record the exact day of gemination. Results: The best treatment observed for germination stimulation radio in the provenance of the Durango batch was with 30-gray radiation increasing by 12% compared to the control, while for the batch from Hidalgo it was the one that received a radiation of 6 gray increasing 56% compared to the control. Limitations on study/implications: for this study only two different populations were evaluated and because there were differences between them, the ideal would be to work with material of the other origins. Findings/conclusions: Gamma radiation at low doses causes an increase in seed germination rate.Objective: To carry out research focused on the germination response of mesquite (Neltuma laevigata) to different doses of gamma radiation (Cobalt 60), in order to obtain a higher germination response than with a non-irradiated seed. Design/Methodology/Approach: Seeds had different collection times and identities. One set was collected in Durango (10 years) and another in Hidalgo (2 months). Both sets were exposed to sixteen different doses of gamma radiation and a control (non-irradiated); they were subsequently subjected to in vitro conditions using a Murashige and Skoog basal medium. They were monitored daily for two weeks in order to develop an accurate record of their germination. Results: The best treatment for the radio-stimulation of germination in the Durango set was observed at 30 gray (12% higher than the control). Meanwhile, the Hidalgo set received 6 gray radiation (56% higher than the control). Study Limitations/Implications: Only two different populations were evaluated for this study. Given the differences found between them, working with material from other origins would be ideal. Findings/Conclusions: Low doses of gamma radiation cause an increase in the germination rate of seeds

Genotoxicity by Electromagnetic Fields

Modern life implies a constant exposure of living organisms to many sources of radiation, especially electromagnetic fields (EMFs) generated by our technological devices. The question of whether or not EMFs in the non-ionizing extremely low frequency (ELF) range can induce genotoxic effects is currently a subject of interest. People of industrialized societies are commonly exposed to EMFs and waves in a very broad range of frequencies, including power lines, telecommunications, and domestic and industrial equipment. In this review, we present controversial evidence from our research group and others of genotoxicity induced by ELF-EMFs, since scientific community consider EMF devices produce marginal amounts of energy, which does not justify any DNA alterations, together with conflicting laboratory results and few epidemiological studies. However, in 2002 the International Agency for Research on Cancer (IARC) categorized ELF-EMFs as being potential carcinogenic and genotoxic agents to humans. The aim of the present chapter is to discuss the role of ELM-EMFs on human genotoxicity

Evaluation of the application of fertilizers and biostimulants in Zephyranthes lindleyana Herb (Amarylidaceae) under greenhouse conditions

Objective: To evaluate the effect of different doses of N, P, K fertilizers and two biostimulants, on growth parameters and vegetative development in plants of the species Z. lindleyana Herb. Design/methodology/approach: An experiment was established under greenhouse conditions under a CRD; ten treatments with five repetitions were tested, with different doses of N, P and K and two biostimulants. The experimental unit was one plant per pot. Data were analyzed with descriptive statistics, non-parametric Kruskal-Wallis tests (α=0.05). Budding, flowering, leaf height, number of leaves and seed production were measured. Results: Vegetative development was distinguished in all plants. Only six treatments showed flowering. The percentage of floral and vegetative sprouting did not show delay or advance in the physiology of the plant. In leaf height and number of leaves, different behaviors were detected in the treatments, not detected in the Kruskal-Wallis tests. The plants treated with high doses of NPK fertilization and combined with biostimulants showed inflorescences and seed production. Limitations on study/implications: Being a native plant with ornamental potential, the collection of this species is a challenge due to the lack of studies on the potential distribution of the species. Findings/conclusions: This species can be cultivated under a greenhouse and pot planting system. Floral budding, height and number of leaves is stimulated by high doses of nitrogen. The combination of NPK and biostimulants favors development/growth and seed production

Dosis altas de radiación gamma (Cobalto60) disminuyen la expresión fenotípica de caracteres en caña de azúcar (Saccharum officinarum L.): High doses of gamma radiation (Cobalt60) decrease the phenotypic expression of characters in sugarcane (Saccharum officinarum L.)

La mutagénesis inducida es una técnica para crear variabilidad genética de manera rápida, directa y fácil en plantas de propagación vegetativa. A través de un agente mutagénico se provocan cambios en una o varias características morfológicas y fisiológicas que se transmiten a su progenie. En México no existe información sobre mutagénesis inducida en el cultivo de caña de azúcar. Por tal motivo, el objetivo del trabajo fue determinar el efecto de la radiación gamma a base de Cobalto60 en la expresión de caracteres fenotípicos en dos variedades comerciales de caña de azúcar. Fueron irradiadas 100 yemas de cada variedad, CP 72-2086 y MEX 69-290, con seis diferentes dosis de radiación gamma: 0, 50, 70, 80, 90 y 100 Grey con Cobalto60. Se sembraron en maceta bajo malla sombra y después se trasplantaron a campo. Los caracteres evaluados fueron emergencia de yemas, caracteres morfológicos y componentes de rendimiento. En general, a mayor dosis de radiación gamma, mayor afectación en la expresión fenotípica de las variables evaluadas, resultando diferentes interacciones entre los factores involucrados. Las dosis de 90 y 100 Grey causaron mayor efecto en la disminución de la expresión fenotípica de los caracteres y demoraron el crecimiento de las plantas. En las interacciones, la variedad CP 72-2086 fue más sensible en la emergencia de yemas, altura de planta, número de macollos y longitud del entrenudo, y la MEX 69-290 en área foliar, los que nos indica que, existe diferente grado de sensibilidad en los caracteres y las variedades evaluadas. Por lo tanto, las dosis altas de radiación gamma causan disminución en diferente proporción en la expresión fenotípica de caracteres y demora el crecimiento de las plantas en caña de azúcar. De igual manera, existe diferente grado de sensibilidad a la radiación gamma en los caracteres y genotipos

Statistical modeling approach for PM10 prediction before and during confinement by COVID-19 in South Lima, Perú

A total of 188,859 meteorological-PM10 data validated before (2019) and during the COVID-19 pandemic (2020) were used. In order to predict PM10 in two districts of South Lima in Peru, hourly, daily, monthly and seasonal variations of the data were analyzed. Principal Component Analysis (PCA) and linear/nonlinear modeling were applied. The results showed the highest annual average PM10 for San Juan de Mirafores (SJM) (PM10-SJM: 78.7 µg/m3) and the lowest in Santiago de Surco (SS) (PM10 -SS: 40.2 µg/m3). The PCA showed the infuence of relative humidity (RH)-atmospheric pressure (AP)temperature (T)/dew point (DP)-wind speed (WS)-wind direction (WD) combinations. Cool months with higher humidity and atmospheric instability decreased PM10 values in SJM and warm months increased it, favored by thermal inversion (TI). Dust resuspension, vehicular transport and stationary sources contributed more PM10 at peak times in the morning and evening. The Multiple linear regression (MLR) showed the best correlation (r = 0.6166), followed by the three-dimensional model LogAP-LogWD-LogPM10 (r = 0.5753); the RMSE-MLR (12.92) exceeded that found in the 3D models (RMSE < 0.3) and the NSE-MLR criterion (0.3804) was acceptable. PM10 prediction was modeled using the algorithmic approach in any scenario to optimize urban management decisions in times of pandemic.Campus San Juan de Luriganch

Azimuthal anisotropy of charged jet production in root s(NN)=2.76 TeV Pb-Pb collisions

We present measurements of the azimuthal dependence of charged jet production in central and semi-central root s(NN) = 2.76 TeV Pb-Pb collisions with respect to the second harmonic event plane, quantified as nu(ch)(2) (jet). Jet finding is performed employing the anti-k(T) algorithm with a resolution parameter R = 0.2 using charged tracks from the ALICE tracking system. The contribution of the azimuthal anisotropy of the underlying event is taken into account event-by-event. The remaining (statistical) region-to-region fluctuations are removed on an ensemble basis by unfolding the jet spectra for different event plane orientations independently. Significant non-zero nu(ch)(2) (jet) is observed in semi-central collisions (30-50% centrality) for 20 <p(T)(ch) (jet) <90 GeV/c. The azimuthal dependence of the charged jet production is similar to the dependence observed for jets comprising both charged and neutral fragments, and compatible with measurements of the nu(2) of single charged particles at high p(T). Good agreement between the data and predictions from JEWEL, an event generator simulating parton shower evolution in the presence of a dense QCD medium, is found in semi-central collisions. (C) 2015 CERN for the benefit of the ALICE Collaboration. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).Peer reviewe

Forward-central two-particle correlations in p-Pb collisions at root s(NN)=5.02 TeV

Two-particle angular correlations between trigger particles in the forward pseudorapidity range (2.5 2GeV/c. (C) 2015 CERN for the benefit of the ALICE Collaboration. Published by Elsevier B. V.Peer reviewe