514 research outputs found

    Mathematical analysis of some diffusion problems associated to the modeling of surfactant compounds at the air-water interface

    Get PDF
    Surfactants are chemical compounds with a particular structure, that is the responsible of their behavior in a water solution. When a new surface is formed in a surfactant solution, surfactant molecules tend to migrate from the bulk of the solution to the surface, consequently varying its surface tension. The dynamic surface tension is a very important property since it plays a major role in several biochemical, biological and industrial processes. All the huge applications of the dynamic surface tension make it a subject of study for a long period of time. There are several publications in the chemical literature dealing with the numerical solutions of the models that describe the surfactant behavior. However, none of them deal with their mathematical analysis. In this thesis, we introduce the mathematical treatment of those models, that consist of the diffusion equation coupled with an adsorption model

    Propuesta de campamentación turística para estudiantes: hacienda y estancia San Isidro, Parroquia Tarqui, Cantón Cuenca

    Get PDF
    El desarrollo de la presente monografía, tiene como objetivo principal crear una propuesta de campamentación turística para la Hacienda y Estancia San Isidro, debido a que en la actualidad en la ciudad de Cuenca no existe un establecimiento dirigido al desarrollo de esta actividad. Para el logro del objetivo planteado, es fundamentalconocer la infraestructura y los atractivos turísticos que posee la hacienda, se detalla el talento humano, los recursos materiales e inmateriales necesario para el camping turístico.También se segmenta el mercado con la finalidad de personalizar el servicio; así pues los niños de 9 a 11 años de edad, poseen las características físicas y psicológicas ideales para el desarrollo de actividades de campismo, debido a ello, se elabora un programa de actividades turísticas para el segmento de mercado escogido. Finalmente, para validar la propuesta de camping turístico, se realiza un campamento piloto con niños de 9 a 11 años de edaden la Hacienda y Estancia San Isidro. En las instalaciones del proyecto se ejecutan actividades de campismo, las cuales fueron previamente planificadas. Posteriormente se evalúa la propuesta por medio de encuestas de satisfacción de servicios prestados, siendo estos resultados, claves para la continuidad del proyecto.The development of this paper, whose main objective is to create a tourist camping proposal for Hacienda y Estancia San Isidro, because there is no establishment led to the development of this activity today in the city of Cuenca. To achieve the stated objective, it is essential to know the infrastructure and attractions that owns the hacienda, human talent is detailed, tangible and intangible resources necessary for the tourist camping. The market is also segmented in order to personalize the service, children of 9-11 years of age, possess the physical and psychological conditions for the development of camping activities, as a result, a program of tourist activities is developed to the chosen market segment. Finally, to validate the proposed tourist campsite, a pilot camp with children 9-11 years of age is performed and stay at Hacienda San Isidro. In the project facilities camping activities, which were previously scheduled run. Subsequently the proposal through satisfaction surveys assessing services provided, and these results are key to the continuity of the project.Ingeniero en TurismoCuenc

    A multimetric diatom index to assess the ecological status of coastal Galician rivers (NW Spain)

    Get PDF
    There are many rivers in northwest Spain as a consequence of the mountainous landscape and the granitic geology subjected to Atlantic influences. Water and epilithic diatoms samples were collected at 72 sites in Galicia flowing into the Atlantic Ocean and Cantabrian Sea in summer 2002–2003 and spring 2004. These sites included minimally disturbed sites, defined as reference sites, and impacted sites which were influenced by different human pressures. We used the diatom assemblages to calculate diatom indices using the Omnidia software, but we also developed new metrics based on the similarity of species composition in reference sites. The response of the metrics was tested in relation to physicochemical variables. We developed a diatom multimetric index (MDIAT) as a combination of metric values. The sensitivity of the MDIAT to organic and nutrient stressors supports the use of this index to classify the ecological status of Galician rivers. The MDIAT showed higher correlations with some variables and nutrients than the individual metrics. According to the MDIAT, 69% of the sites sampled in Galician coastal rivers achieve good ecological status. The MDIAT has been developed specifically for Galician granitic rivers (NW Spain), and has been intercalibrated at the European level in the Central Baltic Rivers GIG. Our study validates the application of this multimetric index to evaluate the water quality in coastal Galician river

    γ-Al2O3 as acid catalyst for dehydration of glucose to 5-hydroxymethylfurfural

    Get PDF
    Currently, the search and development of sustainable feedstocks for chemicals derived from petrol have gained worldwide attraction because of the instability of the price of crude oil, the reduction of fossil oil reserves, and the environmental concerns associated to the greenhouse effect caused by CO2 emissions, being biomass one of the world’s most important renewable carbon sources. The major component of plant-derived biomass are carbohydrates, being of great importance to develop efficient and green approaches to their valorization by conversion into high value-added products. Thus, glucose can be transformed by dehydration into 5-hydroxymethylfurfural (HMF), which is a versatile and key intermediate for the production of a wide variety of biobased chemicals and it is attracting much attention in biofuels and chemical industry. Different catalytic systems have been evaluated for HMF production from C6 carbohydrates as glucose, mostly based on heterogeneous catalysis as alternative to the use of liquid mineral acids. On the other hand, the high surface area, large pore size and thermal and hydrothermal stabilities of some mesoporous solids make them suitable for many catalytic processes. In the present work, the dehydration of glucose to HMF has been evaluated by using different mesoporous γ-Al2O3 with acid, neutral or basic character, in a biphasic water–MIBK solvent system to avoid the HMF degradation and its possible reaction with the intermediates from glucose to give soluble polymers and humins or acetalization with glucose. Different experimental parameters, such as reaction temperature and time, as well as the addition of inorganic salts have been studied in order to reach the maximum HMF yield.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. Ministry of Economy and Competitiveness (CTQ2012-38204-C04-02 project), Junta de Andalucía (RNM-1565) and FEDER fund

    Habilidades informacionales integradas en los grados de edificación y geomática (EPSEB-UPC): caso práctico de cooperación entre docentes y bibliotecarios

    Get PDF
    Se expone el caso práctico de la colaboración entre PDI y PAS de biblioteca para la impartición del itinerario competencial en Habilidades Informacionales en los grados de la Escola Politècnica Superior d'Edificació de Barcelona (EPSEB). Docentes y bibliotecarios diseñan conjuntamente actividades que contemplan sesiones taller especializadas, cursos “ad-hoc” y cursos de contenidos transversales de complejidad progresiva integrados en asignaturas obligatorias. Los contenidos se adaptan a cada asignatura implicada en el itinerario y se da una orientación práctica para captar el interés de los alumnos. Coordinados por el Servei General de Biblioteques de la UPC, los bibliotecarios desarrollan material didáctico de apoyo y valoran los resultados conjuntamente de forma periódica para proponer mejoras. Las actividades se imparten en modalidad presencial y semipresencial. Así mismo, la biblioteca imparte formación al profesorado conducente tanto a desarrollar su faceta investigadora como a dinamizar la docencia en el aula. La experiencia en sesiones formativas desde el año 2000 y la buena acogida por parte de del profesorado y el estudiantado, avalan la puesta en marcha del itinerario a partir de septiembre 2009.Postprint (author's final draft

    Women leaders and female same-sex groups: the same 2030 Agenda objectives along different roads

    Get PDF
    Based on a sample of 4,089 multinational companies over the period 2015–2018, this study analyses the role that women leaders play in relation to the implementation of sustainability strategies to achieve the Sustainable Development Goals (SDGs), and whether this role depends on the proportion of female presence in management teams. The results show that the commitment to the 2030 Agenda is higher in companies with a woman as the Chief Executive Officer (CEO) and/or chairperson of the board of directors, as well as greater gender diversity in both, management teams and the monitoring body. However, the incongruity in the phenomenon of female leadership stereotypes hinders the existence of a complementary relationship that reinforces it. We showed that, consistent with the social role theory, prejudices act as barriers to achieve synergic effects among women in different management positionsS

    A Review of Artificial Intelligence in the Internet of Things

    Get PDF
    Humankind has the ability of learning new things automatically due to the capacities with which we were born. We simply need to have experiences, read, study… live. For these processes, we are capable of acquiring new abilities or modifying those we already have. Another ability we possess is the faculty of thinking, imagine, create our own ideas, and dream. Nevertheless, what occurs when we extrapolate this to machines? Machines can learn. We can teach them. In the last years, considerable advances have been done and we have seen cars that can recognise pedestrians or other cars, systems that distinguish animals, and even, how some artificial intelligences have been able to dream, paint, and compose music by themselves. Despite this, the doubt is the following: Can machines think? Or, in other words, could a machine which is talking to a person and is situated in another room make them believe they are talking with another human? This is a doubt that has been present since Alan Mathison Turing contemplated it and it has not been resolved yet. In this article, we will show the beginnings of what is known as Artificial Intelligence and some branches of it such as Machine Learning, Computer Vision, Fuzzy Logic, and Natural Language Processing. We will talk about each of them, their concepts, how they work, and the related work on the Internet of Things fields

    Gestionando la diversidad cultural en las prisiones. El caso de las mujeres

    Get PDF
    Las mujeres extranjeras que se encuentran cumpliendo condena en centros penitenciarios españoles constituyen un colectivo con identidad propia, con un perfil que difiere del de las autóctonas. En este grupo, identificamos dos situaciones diferenciadas respecto de su proyecto migratorio: las que ya vivían en España antes de entrar en prisión y aquellas que son detenidas en la frontera. Por ello, nos planteamos reconocer las bases de la gestión de la diversidad cultural en las instituciones penitenciarias, con especial atención a las cuestiones de género, centrándonos en la necesidad de la gestión socioeducativa de la diversidad en estos centros

    Kretschmer revisitado: Fatiga mental e ideas de referencia. Contribuciones desde la teoría de la sensibilidad al refuerzo

    Get PDF
    Our aim was to find out the relationship of cognitive/somatic fatigue, sensitivity to punishment (SP)/sensitivity to reward (SR) (Gray) with ideas of reference (IR), and to analyze the mediator role of SP/SR between cognitive/somatic fatigue and IR. The sample was comprised of 79 patients and 329 controls, evaluated with the Referential Thinking Scale (REF), the Fatigue Scale (CFQ) and the SP/SR Questionnaire (SPSRQ). The Baron and Kenny (1986) model and the Preacher and Hayes (2008) procedure were used to test mediation. The model explains 42% of the variance. The direct effect decreased significantly, mainly for SP, and the analysis of the indirect effect is valid for SP but not for SR. Cognitive and somatic fatigue predispose IR (Kretschmer) with participation of the SP system which may act as a mediator, more than a moderator. Cognitive/somatic fatigue may activate a system alerting of aversive (social) stimuli and thus increase the IR.Se analiza la relación entre la fatiga cognitiva/somática y las sensibilidades al castigo (SC)/recompensa (SR) (Gray) con las ideas de referencia (IR). Se estudia el papel mediador/moderador de los procesos SC/SR entre la fatiga cognitiva/somática y las IR. La muestra fueron 79 pacientes y 329 controles, evaluados con la Escala de IR (REF), Escala de Fatiga (CFQ) y Cuestionario de SC/SR (SPRSQ). Se utilizó el modelo de Baron y Kenny (1986) y el procedimiento de Preacher y Hayes (2008). El modelo explica un 42% de la varianza. El efecto directo disminuyó y el análisis del efecto indirecto es válido para la SC pero no para la SR. La fatiga cognitiva y somática predisponen a las IR (Kretschmer), con la participación de la SC, pudiendo ser más moderadora que mediadora. Quizá la fatiga cognitiva y somática activen un sistema sobre los estímulos (sociales) aversivos y se incrementen las IR

    A Novel Nanoproteomic Approach for the Identification of Molecular Targets Associated with Thyroid Tumors

    Get PDF
    A thyroid nodule is the most common presentation of thyroid cancer; thus, it is extremely important to differentiate benign from malignant nodules. Within malignant lesions, classification of a thyroid tumor is the primary step in the assessment of the prognosis and selection of treatment. Currently, fine-needle aspiration biopsy (FNAB) is the preoperative test most commonly used for the initial thyroid nodule diagnosis. However, due to some limitations of FNAB, different high-throughput “omics” approaches have emerged that could further support diagnosis based on histopathological patterns. In the present work, formalin-fixed paraffin-embedded (FFPE) tissue specimens from normal (non-neoplastic) thyroid (normal controls (NCs)), benign tumors (follicular thyroid adenomas (FTAs)), and some common types of well-differentiated thyroid carcinoma (follicular thyroid carcinomas (FTCs), conventional or classical papillary thyroid carcinomas (CV-PTCs), and the follicular variant of papillary thyroid carcinomas (FV-PTCs)) were analyzed. For the first time, FFPE thyroid samples were deparaffinized using an easy, fast, and non-toxic method. Protein extracts from thyroid tissue samples were analyzed using a nanoparticle-assisted proteomics approach combined with shotgun LC-MS/MS. The differentially regulated proteins found to be specific for the FTA, FTC, CV-PTC, and FV-PTC subtypes were analyzed with the bioinformatic tools STRING and PANTHER showing a profile of proteins implicated in the thyroid cancer metabolic reprogramming, cancer progression, and metastasis. These proteins represent a new source of potential molecular targets related to thyroid tumorsThis work was supported by grants from the Instituto de Salud Carlos III (ISCIII), State Research Agency (AEI), and Ministry of Science and Innovation (Spain), with the participation of European FEDER funds, to C.N. (CP16/00139) and J.M.C.-T. (PI19/01316)S
    corecore