Beyond the mincer equation: the internal rate of return to higher education in Colombia

In order to present an estimation of the Internal Rate of Return (IRR) to higher education in Colombia we take advantage of the methodological approach provided by Heckman, Lochner and Todd (2005). Trying to overcome the criticism that surrounds interpretations of the education coefficient of Mincer equations as being the rate ofreturn to investments in education we develop a more structured approach of estimation, which controls for selection bias, includes more accurate measures of labor income and the role of education costs and income taxes. Our results implied a lower rate of return than the ones found in the Colombian literature and show that the Internal Rate ofReturn for higher education in Colombia lies somewhere between 0.074 and 0.128. The results vary according to the year analyzed and individual´s gender. This last result reinforces considerations regarding gender discrimination in the Colombian labor market.Education returns, Mincer Equation, Internal Rate of Return, Colombia

Marketing de influencers y su relación con el comportamiento de compra de los jóvenes trujillanos, 2022

El presente trabajo de investigación tuvo como objetivo determinar la relación del marketing de influencers en el comportamiento de compra de los jóvenes trujillanos, 2022. La metodología de investigación que se utilizó fue de enfoque cuantitativo de tipo básica, correlacional y con un diseño no experimental. En el estudio se tomó en consideración a una población de 63026 jóvenes ubicados en el distrito de Trujillo, obteniendo una muestra representativa de 382 jóvenes trujillanos. La técnica que se utilizó fue la encuesta, su instrumento el cuestionario, desarrollándolo con una escala ordinal de Likert. Finalmente, se concluye en los resultados, el coeficiente Rho de Spearman es de 0,899, en este sentido concluimos que si existe una fuerte correlación positiva entre las variables del marketing de influencers y el comportamiento de compra, por lo que se recomienda a aquellas empresas que no han implementado el marketing de influencers, lo lleven a cabo con el fin de obtener buenos resultados, a través del conocimiento de las características del consumidor, las creencias, actitudes, motivaciones y percepciones de los usuarios permiten que los influencers se conecten con los consumidores y lograr su influencia en la compra.The objective of this research work was to determine the relationship of influencer marketing in the purchasing behavior of young people from Trujillo, 2022. The research methodology used was a quantitative approach of a basic, correlational type and with a non-experimental design. In the study, a population of 63,026 young people located in the district of Trujillo was taken into consideration, obtaining a representative sample of 382 young people from Trujillo. The technique used was the survey, its instrument the questionnaire, developing it with an ordinal Likert scale. Finally, in the results, Spearman's Rho coefficient is 0.899, which can confirm that there is a strong positive correlation between influencer marketing variables and purchasing behavior, so it is recommended for those companies that have not implemented influencer marketing, carry it out in order to obtain good results, through knowledge of consumer characteristics, beliefs, attitudes, motivations and perceptions of users allow influencers to connect with consumers and achieve their purchase influence.Tesi

Clusters en cultivos ilícitos: determinantes y dinámicas

Los datos recientes de áreas de cultivos ilícitos indican que a pesar de las fumigaciones, la producción total se ha reducido levemente y los cultivos se han dispersado. Se plantea un modelo teórico que analiza las decisiones tomadas por los cultivadores sobre la localización de sus parcelas, basando esta escogencia en la minimización local de los costos esperados. Se utiliza un modelo de agentes para la simulación de la naturaleza compleja de las dinámicas estudiadas. Se encuentra que el incentivo para agruparse aumenta con las economías a escala y se reduce con la expectativa del castigo, sobretodo en zonas con alta densidad de cultivadores.

Caracterización Macroscópica De Morteros Romanos De Tipo Industrial En Villamanta (Madrid). Primeros Datos

The objective of this article is to show the results obtained from the physical and macroscopic characterization of the mortars sampled by Isabel Marqués and Alejandro Bermúdez, archaeological directors of the intervention carried out in El Tejar settlement, in the municipality of Villamanta (Madrid, Spain). The results of this work have determined a relevant typological classification among the samples, highlighting the presence of siliceous aggregates, ceramics in some mortars, a very varied grading and a distribution of the components that have conditioned the conservation. Of the four samples taken -VMT1 to VMT4- one of them has an aqueous pigmentation, belonging to an inside plaster, while the others correspond to lime mortars with aggregates from hydraulic surfaces. The archaeological investigation of the deposit of Villamanta is complemented by an implementation check of lime mortars, being one of the most important Roman context of Madrid. This research add a sequence of new results around the Roman mortars and implements a methodology in the study of the historical mortars

Non-Linear Inner Structure of Topological Vector Spaces

Inner structure appeared in the literature of topological vector spaces as a tool to characterize the extremal structure of convex sets. For instance, in recent years, inner structure has been used to provide a solution to The Faceless Problem and to characterize the finest locally convex vector topology on a real vector space. This manuscript goes one step further by settling the bases for studying the inner structure of non-convex sets. In first place, we observe that the well behaviour of the extremal structure of convex sets with respect to the inner structure does not transport to non-convex sets in the following sense: it has been already proved that if a face of a convex set intersects the inner points, then the face is the whole convex set; however, in the non-convex setting, we find an example of a non-convex set with a proper extremal subset that intersects the inner points. On the opposite, we prove that if a extremal subset of a non-necessarily convex set intersects the affine internal points, then the extremal subset coincides with the whole set. On the other hand, it was proved in the inner structure literature that isomorphisms of vector spaces and translations preserve the sets of inner points and outer points. In this manuscript, we show that in general, affine maps and convex maps do not preserve inner points. Finally, by making use of the inner structure, we find a simple proof of the fact that a convex and absorbing set is a neighborhood of 0 in the finest locally convex vector topology. In fact, we show that in a convex set with internal points, the subset of its inner points coincides with the subset of its internal points, which also coincides with its interior with respect to the finest locally convex vector topology

Data for the modelling of the future power system with a high share of variable renewable energy

Energy and power system models have become necessary tools that provide challenges and technical and economic solutions for integrating high shares of Variable Renewable Energy. Models are focused on analysing strategies of power systems to achieve their decarbonisation targets. The data presented in this paper includes the model algorithm, inputs, equations, modelling assumptions, supplementary materials, and results of the simulations supporting the research article titled “Facing the high share of variable renewable energy in the power system: flexibility and stability requirements”. The analysis is based on data from the system operator of one of the European Union member states (Spain). The developed model allows making projections and calculations to obtain the power generation of each technology, the international interconnections, inertia, emissions, system costs and flexibility requirements of new technologies. These data can be used for energy policy development or decision making on power capacity and the balancing needs of the future power system.Ministerio de Ciencia e Innovación PID2020-114725RA-I00Universidad de Sevilla VI PPIT-USPlan nacional I+D+I CTM2016-78089-RJunta de Andalucía P18-RT-451

Diversidad regional de Amphipoda en el mar Caribe

The order Amphipoda is one of the most diverse within Peracarids, and comprises 6 950 described marine species. Amphipod research in the Caribbean Sea began in the late 1 800s, but has increased significantly since 1 980. In this study, we analized the amphipod biodiversity (Caprellidea, Gammaridea, Hyperiidea, and Ingolfiellidea) of the Caribbean Sea. For this, we compiled available data on species diversity of marine amphipods (data bases: WoRMS and OBIS and published species lists) into a comprehensive taxonomic list by country for the ecoregions of the Caribbean. Additionally, we analized the relative contribution of each country to regional diversity and the rate of discovery of new species. The Caribbean amphipod fauna is composed of 535 species within 236 genera and 73 families for the higher taxon. The Western Caribbean ecoregion holds the largest diversity (282 species), while the Eastern Caribbean recorded the lowest one (73). Mexico and Venezuela recorded the largest number of species with 266 and 206, respectively. Twelve countries had less than 50 species. The richest suborder is the Gammaridea with 381 species followed by the suborder Hyperiidea with 116. From the total of 535 amphipod species reported for the Caribbean region, 218 have the Caribbean as the holotype locality, and 132 are endemic (about 25% of the total). Areas of higher diversity seem to be concentrated along the Mexican Caribbean, Cuba and the Northern coast of South America (VenezuelaColombia); however, such pattern is most likely reflecting local collection efforts and taxonomic expertise rather than actual distribution. Knowledge of amphipod species is mostly limited to shallow, near-shore waters, with little information available on the deep sea fauna. Regional research priorities for this group should be focused on completing shallow water coastal inventories of species in Central America and the Greater and Lesser Antilles. In addition, sampling the deep sea ecosystems should follow along with other particular habitats such as anchialine cave systems. It is also neccessary to increase ecological research efforts, mainly in some speciose suborders, including the Caprellidea and Hyperiidea, known to exhibit high diversity in other tropical localities

Modification of microbial polymers by thiol-ene click reaction: Nanoparticle formation and drug encapsulation

Comb-like amphiphilic polymers were obtained by grafting long paraffinic chains on microbial poly(¿,dl-glutamic acid) and poly(ß,l-malic acid) through two steps, i.e. allylation of the carboxylic side groups followed by UV-initiated thiol-ene click reaction with 1-alkanethiols bearing 8, 12 and 16 carbon atoms, and their characterization was accomplished by 1H NMR, GPC and DSC. The grafted polymers were capable of self-assembling in nanoparticles with diameters in the 80–240 nm range. Incubation in water under physiological conditions led to hydrolysis of the lateral ester bonds followed by scission of the polyamide or polyester main chain. The model drugs, Theophylline and Carbamazepine, were efficiently encapsulated in these systems with much better results attained for the later. Drug release from nanoparticles incubated under physiological conditions occurred with a burst effect and were completely discharged in 24 h. Release profiles recorded from drug-loaded films suggested that the drug was delivered in both cases through a diffusion process.Peer ReviewedPostprint (author's final draft

Addition of amines to molasses and lees as corrosion inhibitors in sustainable de-icing materials

Producción CientíficaThe waste formed during sugar- and wine-making activities has attracted our attention given its ability to inhibit corrosion in the presence of brine in a de-icing formulation. Herein the addition of amines to de-sugared beet molasses and winery lees is found to improve their anti-corrosive properties. Thus, weight-loss experiments clearly show that the addition of a small amount of amines to molasses or lees results in marked corrosion inhibition on carbon and galvanized steel. Subsequent electrochemical experiments and microscopy studies supported this finding. In addition, microscopy images indicated that triethanolamine was the best candidate amongst the amines tested for use in the final de-icing formulation. Ice-melting experiments demonstrated that the presence of molasses/lees together with triethanolamine does not alter the properties of the de-icing agent. When corrosion on galvanized and carbon steel probes was measured under environmental conditions, a decrease of 88% for galvanized steel and 65% for carbon steel was achieved due to the inhibiting action of the molasses/triethanolamine mixture. These results suggest that the addition of molasses/lees and triethanolamine to brine-based de-icing agents is recommended.Junta de Castilla y Leon - Fondo Europeo de Desarrollo Regional (project 04/8/VA0013

Caprellids (Crustacea: Amphipoda: Caprellidae) from shallow waters of the Caribbean coast of Venezuela

AbstractThe caprellidean fauna of Venezuela is investigated. Twenty-seven stations in shallow waters of the states Falcón, Carabobo, Aragua, Anzoátegui, Sucre and Nueva Esparta were sampled, and the caprellids were sorted and identified. A total of 3984 specimens were identified; 12 species in eight genera are reported. Two species, Caprella penantis Leach, 1814 and Paracaprella digitimanus Quitete, 1971, are new records for Venezuelan waters. The electronic supplement to this paper includes illustrations and a key to all caprellid species known from Venezuela, as well as comments on their distribution and ecology