1,229 research outputs found

    Behavior of chile Pepper Húngaro (Capsicum annuum) in mixtures of vermicompost-sand under protected conditions

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    El trabajo se realizó para determinar la concentración óptima de la mezcla vermicompost:arena (VC:A; v:v) que satisfaga las necesidades nutricionales del cultivo de chile tipo Húngaro (Capsicum annum) bajo condiciones protegidas. Las mezclas evaluadas fueron cuatro combinaciones de VC:A con las relaciones 1:1, 2:1, 3:1, 4:1 y un testigo 0:1 (arena más solución nutritiva). Las variables evaluadas fueron altura de planta y diámetro basal del tallo, en el fruto longitud, diámetro ecuatorial, espesor del pericarpio, número de lóculos, peso y rendimiento. Se utilizó un diseño en bloques al azar con cinco repeticiones. Para determinar el efecto de los tratamientos sobre las variables evaluadas se aplicó el ANDEVA y para la comparación de medias se utilizó la prueba de Tukey0,05. Se determinó que para las variables evaluadas en el cultivo del chile como: altura de planta, diámetro basal del tallo, longitud del fruto, espesor del pericarpio, número de frutos por planta, peso de fruto y rendimiento, presentaron diferencias altamente significativas (P≤0,01) mientras que las variables diámetro ecuatorial y número de lóculos del fruto resultaron estadísticamente iguales. La relación 1:1 en volumen de VC:A resultó la mezcla más adecuada para el desarrollo del cultivo de chile tipo Húngaro bajo condiciones protegidas.Work was carried out to determine optimal concentration of the mixture vermicompost: sand (VC:S, by volume) which meets nutritional requirements of the cultivation of chile pepper type Hungaro (Capsicum annum) under protected conditions. The mixtures evaluated were four combinations of VC:S with ratios 1:1, 2:1, 3:1, 4:1 and a control 0:1 (sand with nutrient solution). The variables evaluated were plant height and basal stem diameter, in the fruit: length, equatorial diameter, pericarp thickness, number of locules, weight, and yield. The experimental design was of randomized blocks with five replications. Order to determine the treatment effects on the evaluated variables ANOVA was applied and averages were compared by the Tukey test(5%). It was established that of the variables evaluated en chile pepper as plant height, basal stem diameter, fruit length, pericarp thickness, fruit weight and yield had significant differences (P≤0.01), while equatorial diameter and number of locules did not show any statistical differences between treatments evaluated. The ratio of 1:1 by volume of VC:S was most appropriate mixture for development of chile pepper type Hungaro in protected conditions.Fil: Moreno Reséndez, Alejandro.Fil: Rodríguez Dimas, Norma.Fil: Reyes Carrillo, José Luis.Fil: Márquez Quiroz, César.Fil: Reyes González, Jovan

    Pollen collection and honey bee forager distribution in cantaloupe

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    Honey bee (Apis mellifera, L.) pollen collection and forager distribution were examined during the 2002 summer in a cantaloupe (Cucumis melo, L., Cruiser cv ) field with plastic mulch and drip irrigated. The experimental site was located near the INIFAP Campo Experimental La Laguna, Matamoros, Coahuila within La Laguna region, Mexico. Two trials were conducted in the same location, but were separated by a 800 m wide pecan orchard. Both cantaloupe trials were planted the same date. Trial 1. Nine honey-bee hives were placed in a three hectare field at the start of bloom. Each hive was fitted with a modified-Ontario pollen trap. The pollen was collected one day a week from each colony every hour beginning from 8:30 hr to 14:30 hr during the first four blooming weeks of the crop. Trial 2. Three weeks after the start of bloom, in a ten-ha field 30 honey bee colonies were located. In four randomlyselected rows of 105 m long, 10 m transects at 25, 50, 75 and 100 m distances from the apiary were marked. The foraging bees were counted simultaneously at the transects every half hour from 7:30 hr until 20:30 hr at the same pollen collection-day during the third week of cantaloupe bloom. Pollen collection was higher early in the morning (22.6 g per colony), dropping to medium amount from 9:30 hr (13.7 g), 10:30 hr (12.5 g) to 11:30 hr (9.5 g) and remaining low from 12:30 through the afternoon (less than 2.6 g per colony; p< 0.05). The distribution pattern showed that bees were in the cantaloupe after 8:00 hr, reaching a maximum between 10:30 hr and 14:30 hr when the bees began to decrease, until foraging flights ceased completely at about 20:30 hr. No statistical differences were found in the number of foraging bees among the evaluated distances from the apiary.Durante el verano del 2002 la colecta de polen y la distribución de las abejas (Apis mellifera L.) pecoreadoras fueron estudiadas en el cultivo de melón (Cucumis melo L., cv Cruiser ) bajo condiciones de riego por goteo y acolchado plástico. El lote experimental estuvo localizado cerca del Campo Experimental La Laguna del INIFAP, en el municipio de Matamoros, Coahuila, México. Dos experimentos se realizaron en el mismo predio, en lotes separados 800 m por una huerta de nogal. Ambas superficies de melón fueron sembradas en la misma fecha. Experimento N° 1. Al inicio de la floración se colocaron nueve colmenas en tres hectáreas de cultivo. Cada colmena contó con una trampa de polen tipo Ontario modificada. El polen se colectó cada hora de cada colmena un día por semana de las 8:30 hr a las 14:30 hr durante las cuatro primeras semanas de floración del cultivo. Experimento N° 2. Tres semanas después del inicio de la floración se colocaron 30 colmenas en un campo de melón de diez hectáreas. En cuatro surcos de 105 m de longitud se marcaron transectos de diez metros a 25, 50, 75 y 100 metros de distancia del apiario. Las abejas pecoreadoras fueron contadas simultáneamente en cada transecto cada media hora de las 7:30 hr hasta las 20:30 horas, el mismo día en que fue colectado el polen de la tercera semana de floración. La colecta de polen fue mayor temprano por la mañana (22.6 g por colmena), disminuyendo a una cantidad media de las 9:30 hr (13.7 g), 10:30 hr (12.5 g) a las 11:30 hr (9.5 g) y permaneciendo baja desde las 12:30 hasta el mediodía (menos de 2.6 g por colmena; p<0.05). El patrón de distribución mostró que las abejas se presentaron en el cultivo de melón después de las 8:00 hr y alcanzaron su máximo entre las 10:30 hr y las 14:30 hr cuando las abejas iniciaron su disminución hasta el cese de los vuelos a las 20:30 hr. No se encontraron diferencias significativas en el número de abejas pecoreadoras a las diferentes distancias del apiario que fueron evaluadas

    Especies de plantas visitadas por abejas pecoreadoras durante la inducción de polinización en melón.

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    The purpose of the research was to determine, by identifying pollen in corbicular pellets, the different plant species visited by honeybees (Apis mellifera L.) during cantaloupe (Cucumis melo L.) induced pollination. This work was carried out in La Laguna region, located in the states of Coahuila and Durango, Mexico in the spring of 2003. During the first 31 days of cantaloupe bloom, 18 honey bee colonies were placed in a six ha field, nine of which had a bottom pollen trap. Trapped pollen was collected twice per a week weighed and frozen. Through the year, anthers of wild and cultivated flowering plant species around the cantaloupe field and in La Laguna were collected, acetolyzed and preserved for pollen identified. Corbicular pollen from the 5th, 9th, 12th, 20th, 24th and 31st sample dates after start of staminate bloom was processed, identified and counted by microscopy. Pollen size was calculated with the formula: volume V=?a2b where a is the major axe and b the minor axis and multiplied by the number of pollen grains to get the total volume. Cantaloupe pollen made up 8.7 %, 9.8%, 17.6 %, 9.3 %, 28.1% and 83.5% of that collected (number of pollen grains) on respectively for the sample dates. The percentage of volume basis pollen for cantaloupe was: 51.6%, 85.0%, 66.6 %, 84.4 %, 68.9% and 95.0% respectively. It is concluded that the cantaloupe was the main species visited as a plant pollen source for pollinating honeybees and that the plants present in the sample like mesquite (Prosopis juliflora (Swartz) DC.), alfalfa (Medicago sativa L.), creosote bush (Larrea tridentata (DC) Cov.), cucumber (Cucumis sativus L.), London rocket (Sysimbrium irio L.) and sorghum (Sorghum vulgare L.) were species visited as supplementary pollen sources.El objetivo de la investigación fue determinar, a través de la identificación del polen corbicular, las diferentes especies de plantas que son visitadas por las abejas (Apis mellifera L.) durante la polinización inducida del melón (Cucumis melo L.). El trabajo se llevó a cabo en La Laguna ocalizada en los estados de Coahuila y Durango, México en la primavera del 2003. Durante los primeros 31 días de la floración del melón, un campo de seis hectáreas fue polinizada por 18 colmenas, nueve de las cuales tenía una trampa para captura de polen. El polen fue colectado dos veces por semana, pesado y congelado. Durante el año se colectaron anteras de plantas silvestres y cultivadas en floración alrededor del cultivo y en la región para preservarlas e identificar su polen usando la técnica de acetolisis. El polen corbicular, muestreado los días 5°, 9°, 12°, 20°, 24° y 31° contados a partir del inicio de la aparición de las flores estaminadas, fue procesado y contado en el microscopio óptico. El tamaño del polen fue calculado mediante la fórmula: volumen V=?a2b donde a es el eje mayor y b el eje menor y multiplicado por el número de granos de polen se obtuvo el volumen total. El polen de melón fue el 8.7 %, 9.8%, 17.6 %, 9.3 %, 28.1% y 83.5% del colectado (en base al número de granos) respectivamente en las fechas de muestreo. El porcentaje del polen de melón en base al volumen fue: 51.6%, 85.0%, 66.6 %, 84.4 %, 68.9% y 95.0% respectivamente. Se concluye que el melón fue la principal planta visitada por las abejas como fuente de polen y que las especies de plantas con mayor número de granos de polen presentes en las muestras como mezquite (Prosopis juliflora (Swartz) DC.), alfalfa (Medicago sativa L.), gobernadora (Larrea tridentata (DC) Cov.), pepino (Cucumis sativus L.), mostacilla (Sysimbrium irio L.) y sorgo (Sorghum vulgare L.) fueron especies visitadas como fuentes suplementarias de polen

    Recent Advances in the Prins Reaction

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    The Prins reaction is a very convenient synthetic platform for the preparation of oxygen-containing heterocyclic compounds, especially tetrahydropyrans and tetrahydrofurans. While this reaction has been extensively used by synthetic chemists since its discovery, the last years have witnessed impressive improvements in its performance and scope and especially in the development of new catalytic and enantioselective versions. This mini-review presents these recent advances through selected representative examples.The authors thank the Spanish Agencia Estatal de Investigacion (FEDER-PID2020-118422-GB-I00) and the Basque Government (Grupos IT1558-22) for financial support

    Recent Developments in Transannular Reactions

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    Transannular reactions have shown a remarkable performance for the construction of polycyclic scaffolds from medium- or large-sized cyclic molecules in an unconventional manner. Recent examples of transannular reactions reported from 2011 have been reviewed, emphasizing the excellent performance of this approach when accessing the target compounds. This review also highlights how this methodology provides an alternative approach to other commonly used strategies for the construction of cyclic entities such as cyclization or cycloaddition reactions.MCIU (FEDER-PID2020-118422-gb-100), Basque Government (IT908-16

    Desymmetrization of Oxabenzonorbornadienes through Brønsted Acid-Catalyzed Enantioselective (3+2) Cycloaddition with Hydrazones

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    This work presents the desymmetrization of oxabenzonorbornadienes through the (3+2) cycloaddition reaction with hydrazones using a chiral Brønsted acid such as a BINOL-derived phosphoramide. This chiral acid catalyst appears as the most effective mediator for the activation of the hydrazone via hydrazonium cation that reacts in a (3+2) fashion with the oxabenzonorbornadiene as the olefinic counterpart. Under the optimized conditions, the reaction provided selectively exo cycloaddition products in satisfactory yields and moderate stereoselectivities. The scope of the reaction was explored displaying 21 examples of these highly functionalized tetrahydroepoxybenzoindazole compounds. A reaction mechanism is proposed to explain the outcome of the reaction.Grant PID2020-118422GB-I00 funded by MCIN/AEI/10.13039/501100011033 and by “ESF Investing in your future” is gratefully acknowledged. Financial support by the the Basque Government (Grupos IT1558-22) is also gratefully acknowledged

    Asymmetric Dual Enamine Catalysis/Hydrogen Bonding Activation

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    Asymmetric enamine base activation of carbonyl compounds is a well-known and widely used strategy for providing functionalization of organic compounds in an efficient way. The use of solely organic substances, which in most cases are commercially available primary or secondary amines that are easy to obtain, avoids the use of hazardous substances or metal traces, making this type of catalysis a highly convenient methodology from a sustainable point of view. In many cases, the reactivity or the stereoselectivity obtained is far from being a practical and advantageous strategy; this can be improved by using a hydrogen bonding co-catalyst that can help during the activation of one species or by using a bifunctional catalyst that can direct the approximation of reagents during the reaction outcome. In this review, we describe the most efficient methodologies that make use of a dual activation of reagents for performing α-functionalization (enamine activation) or remote functionalization (such as dienamine or trienamine activation) of carbonyl compounds.PID2020-118422GB-I00 funded by MCIN/AEI/10.13039/501100011033 and by “ESF Investing in your future” are gratefully acknowledged together with the Basque Government (Grupos IT1558-22) and the University of the Basque Country (UPV/EHU)

    Ion-pairing catalysis in the enantioselective addition of hydrazones to N-acyldihydropyrrole derivatives

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    We have demonstrated that dihydropyrrole-based enamide derivatives can act as efficient precursors of chiral quaternary N-acyliminium salts under Brønsted acid catalysis that undergo reactions with hydrazones, the latter participating as masked nucleophilic carbonyl group equivalents. The optimized methodology provides a variety of enantiopure α-substituted proline derivatives in excellent yields, being even compatible with disubstituted β-enamides that generate two contiguous stereocentres.Spanish MINECO(FEDER-CTQ201783633-P), the Basque Government (IT908-16) and UPV/EHU (EHUA15/24 and a fellowship to N.Z.

    Comportamiento del Chile Húngaro (Capsicum annuum) en mezclas de vermicompost- arena bajo condiciones protegidas

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    Work was carried out to determine optimal concentration of the mixture vermicompost: sand (VC:S, by volume) which meets nutritional requirements of the cultivation of chile pepper type Hungaro (Capsicum annum) under protected conditions. The mixtures evaluated were four combinations of VC:S with ratios 1:1, 2:1, 3:1, 4:1 and a control 0:1 (sand with nutrient solution). The variables evaluated were plant height and basal stem diameter, in the fruit: length, equatorial diameter, pericarp thickness, number of locules, weight, and yield. The experimental design was of randomized blocks with five replications. Order to determine the treatment effects on the evaluated variables ANOVA was applied and averages were compared by the Tukey test(5%). It was established that of the variables evaluated en chile pepper as plant height, basal stem diameter, fruit length, pericarp thickness, fruit weight and yield had significant differences (P≤0.01), while equatorial diameter and number of locules did not show any statistical differences between treatments evaluated. The ratio of 1:1 by volume of VC:S was most appropriate mixture for development of chile pepper type Hungaro in protected conditions.El trabajo se realizó para determinar la concentración óptima de la mezcla vermicompost:arena (VC:A; v:v) que satisfaga las necesidades nutricionales del cultivo de chile tipo Húngaro (Capsicum annum) bajo condiciones protegidas. Las mezclas evaluadas fueron cuatro combinaciones de VC:A con las relaciones 1:1, 2:1, 3:1, 4:1 y un testigo 0:1 (arena más solución nutritiva). Las variables evaluadas fueron altura de planta y diámetro basal del tallo, en el fruto longitud, diámetro ecuatorial, espesor del pericarpio, número de lóculos, peso y rendimiento. Se utilizó un diseño en bloques al azar con cinco repeticiones. Para determinar el efecto de los tratamientos sobre las variables evaluadas se aplicó el ANDEVA y para la comparación de medias se utilizó la prueba de Tukey0,05. Se determinó que para las variables evaluadas en el cultivo del chile como: altura de planta, diámetro basal del tallo, longitud del fruto, espesor del pericarpio, número de frutos por planta, peso de fruto y rendimiento, presentaron diferencias altamente significativas (P≤0,01) mientras que las variables diámetro ecuatorial y número de lóculos del fruto resultaron estadísticamente iguales. La relación 1:1 en volumen de VC:A resultó la mezcla más adecuada para el desarrollo del cultivo de chile tipo Húngaro bajo condiciones protegidas
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