Results 41 to 50 of about 76,812 (158)
Estudios sobre el Mensaje Periodístico, 2012 La interactividad y el multimedia son dos de los pilares fundamentales del periodismo digital, junto a la hipertextualidad. Dado su carácter relativamente incipiente, analizamos empíricamente el uso en cabeceras internacionales.
Joan Francesc Fondevila Gascón
doaj +1 more source
Understanding Chiral Proton Catalysis Using Cinchonium Derivatives in aza‐Michael Additions
Advanced Synthesis &Catalysis, Volume 367, Issue 11, June 3, 2025.Abstract This work presents a detailed mechanistic study of a quininium‐catalyzed aza‐Michael reaction, providing essential information for advancing chiral proton catalysis (CPC). The use of cinchona derivatives as chiral proton catalysts demonstrates their potential beyond their conventional roles as base‐promoted and phase‐transfer catalysts ...
Fernando Auria‐Luna +4 more
wiley +1 more source
Sensors, 2016 In this work we demonstrate the ability of a multifaceted N,N′-disubstituted urea to selectively recognize fluoride anion (F−) among other halides. This additional function is now added to its already reported organocatalytic and organogelator properties.
Jana Schiller +5 more
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Multicomponent Cyanation of 2‐Amino‐3‐cyano‐4H‐chromenes in Aqueous Media
Asian Journal of Organic Chemistry, Volume 13, Issue 12, December 2024.Chromenes, especially 2‐amino‐3‐cyano‐4H‐chromene derivatives, are present in biologically active compounds with potential properties, although the number of synthetic methods to date is limited. Here, we report a new protocol using a mild source of cyanide (acetone cyanohydrin), green solvents, and catalytic conditions via a multicomponent approach ...
Sandra Ardevines +5 more
wiley +1 more source
PKI* y firmas digitales: aplicaciones reales
Inventum Ingeniería, Tecnología e Investigación, 2007 El uso de las claves públicas es la base para que se dé el comercio electrónico. Este documento busca sustentar que la administración de la infraestructura de llaves públicas o PKI es la solución para conseguir seguridad de la información en los negocios
Armando Carvajal
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The Journal of Latin American and Caribbean Anthropology, Volume 29, Issue 4, Page 352-363, December 2024.Abstract This paper explores selective aspects of the historical processes of organization of the kichwa peasantry in the Andes of Ecuador. Based on the analysis of two representative cases of confrontation between peasants and landowners over access to land in the province of Chimborazo, it discusses the relevance of the concept of “gamonalismo” as ...
Víctor Bretón
wiley +1 more source
Diatomeas (Bacillariophyceae) en humedales de altura de la Provincia de Catamarca (Argentina). III [PDF]
, 2015 En el marco de la investigación de humedales de alta montaña que realizamos desde 1998, hemos estudiado ya 24 cuerpos de agua de esta provincia. Con el objetivo de ampliar los conocimientos de la flora diatomológica en ambientes de alta montaña, en esta ...
Maidana, Nora Irene +1 more
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New Twists in the Chemistry of Thioureas: 1,3‐Thiazolidines as a Vector of Sustainability
Chemistry – A European Journal, Volume 30, Issue 57, October 11, 2024.A new sustainable method for synthesizing 1,3‐N,S‐heterocycles, including 1,3‐thiazolidine‐2‐imines and 4,5‐dihydrothiazol‐2‐amines is reported. This innovative approach offers considerable shorter reaction times with higher yields, reduced energy consumption, and the elimination of hazardous chemicals.
Guillermo Canudo‐Barreras +2 more
wiley +1 more source
Poder de mercado y transmisión asimétrica de precios en el mercado de hidrocarburo en Nicaragua [PDF]
, 2009 LA INVESTIGACIÓN DESCRIBE UNA CADENA DE COMERCIALIZACIÓN DE PRODUCTOS derivados del petróleo -específicamente de diesel y gasolinas- altamente concentrada en Nicaragua, donde una empresa concentra un gran porcentaje del mercado en la fase de distribución
Eddy Gamboa +7 more
core +3 more sources
Policy &Internet, Volume 16, Issue 3, Page 628-642, September 2024.Abstract Infrastructure siting has been shown to lead to high contestation across political systems. To counteract this, policymaking has introduced participatory instruments that were recently supplemented by web‐based tools. Drawing on theoretical perspectives on policy conflict, this paper investigates how different conflict intensities reflected in
Ilana Schröder, Nils C. Bandelow
wiley +1 more source