399 research outputs found

    Preparación para el trabajo de los jóvenes contemporáneos en una sociedad postindustrial: trabajo, educación y globalización

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    En la sociedad contemporánea, el dilema planteado a los jóvenes entre la educación y su función academicista, por un lado, y la capacitación profesional para una futura inserción ocupacional, por otro, constituye un problema acuciante. En el presente artículo se analiza esta cuestión desde una aproximación psicosocial. El objetivo es mostrar que la escuela continúa siendo una institución moderna en sus métodos disciplinares, valores, discursos, búsquedas, fines e intereses, heredera de un patrimonio ilustrado, en unas condiciones que definen una sociedad calificada de postmoderna, postindustrial, tecnológica y global. Se analizan los panoramas y retos educativos ante tales demandas en las circunstancias cambiantes que se describen. Se reflexiona sobre la vinculación que hay entre escuela y trabajo y acerca de la falta de equiparación entre su cualificación profesional y el desempeño de puestos de trabajo

    Can Latin America Move Forward after a Lost Decade in Technical Change? …Looking at Opportunities for Knowledge-based Change in Times of Increasing Uncertainty

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    In view of the current global context, which challenges are facing science- and technology-based developments and cooperation in a way to contribute for policies that stimulate localized learning, innovation and endogenous development in Latin America? This broad question has motivated the work behind the Special Issue introduced by this paper, which considers the development of case studies in selected Latin America regions. The analysis lead us to argue that value-based networks have the potential to make both public policies and markets more effective, promoting learning trajectories for the inclusive development of regions. But they require effective public investments to keep attracting and qualifying human resources, together with long-term developments towards technical industries and export capacity for emerging markets worldwide. Our analysis argues about the unique potential for further developing Latin America through strategic international, knowledge-based ventures, exploring the emerging role the internationalization of universities and scientific institutions may play at a global level. Above all, they require the systematic observation of science and technical change in international comparison, as well as a relational infrastructure for collective action, at an international level, in a context much influenced by a dynamic of change and a necessary balance between the creation and diffusion of knowledge towards the endogenous development of all parts involved. The role of Latin America Universities and science policies based on international cooperation are considered to be particularly important in this process.published_or_final_versio

    Zwitterionic Rhodium and Iridium Complexes Based on a Carboxylate Bridge-Functionalized Bis-N-heterocyclic Carbene Ligand: Synthesis, Structure, Dynamic Behavior, and Reactivity

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    A series of water-soluble zwitterionic complexes featuring a carboxylate bridge-functionalized bis-N-heterocyclic carbene ligand of formula [Cp MIIICl{(MeIm)2CHCOO}] and [MI(diene){(MeIm)2CHCOO}] (Cp* = 1, 2, 3, 4, 5-pentamethylcyclopentadienyl; M = Rh, Ir; MeIm = 3-methylimidazol-2-yliden-1-yl; diene = 1, 5-cyclooctadiene (cod), norbornadiene (nbd)) were prepared from the salt [(MeImH)2CHCOO]Br and suitable metal precursor. The solid-state structure of both types of complexes shows a boat-shaped six-membered metallacycle derived of the ¿2C, C' coordination mode of the bis-NHC ligand. The uncoordinated carboxylate fragment is found at the bowsprit position in the Cp MIII complexes, whereas in the MI(diene) complexes it is at the flagpole position of the metallacycle. The complexes [RhI(diene){(MeIm)2CHCOO}] (diene = cod, nbd) exist as two conformational isomers in dichloromethane, bowsprit and flagpole, that interconvert through the boat-to-boat inversion of the metallacycle. An inversion barrier of ~17 kcal·mol-1 was determined by two-dimensional exchange spectroscopy NMR measurements for [RhI(cod){(MeIm)2CHCOO}]. Reaction of zwitterionic Cp MIII complexes with methyl triflate or tetrafluoroboric acid affords the cationic complexes [Cp MIIICl{(MeIm)2CHCOOMe}]+ or [Cp MIIICl{(MeIm)2CHCOOH}]+ (M = Rh, Ir) featuring carboxy and methoxycarbonyl functionalized methylene-bridged bis-NHC ligands, respectively. Similarly, complexes [MI(diene){(MeIm)2CHCOOMe}]+ (M = Rh, Ir) were prepared by alkylation of the corresponding zwitterionic MI(diene) complexes with methyl triflate. In contrast, reaction of [IrI(cod){(MeIm)2CHCOO}] with HBF4·Et2O (Et = ethyl), CH3OTf, CH3I, or I2 gives cationic iridium(III) octahedral complexes [IrIIIX(cod){(MeIm)2CHCOO}]+ (X = H, Me, or I) featuring a tripodal coordination mode of the carboxylate bridge-functionalized bis-NHC ligand. The switch from ¿2C, C' to ¿3C, C', O coordination of the bis-NHC ligand accompanying the oxidative addition prevents the coordination of the anions eventually formed in the process that remain as counterions

    Mechanistic studies on the: N -alkylation of amines with alcohols catalysed by iridium(i) complexes with functionalised N-heterocyclic carbene ligands

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    Iridium(i) cyclooctadiene complexes featuring O- and N-donor functionalised NHC ligands efficiently catalyse the C-N coupling of amines with alcohols through a borrowing hydrogen mechanism. These catalysts have been applied for the N-alkylation of several aromatic and aliphatic primary amines with a range of alcohols including benzyl alcohol derivatives, straight-chain primary alcohols and secondary alcohols. The cationic complex [Ir(NCCH3)(cod){MeIm(2-methoxybenzyl)}]+ (cod = 1, 5-cyclooctadiene, MeIm = 3-methylimidazol-2-ylidene) having a rigid O-donor wingtip exhibits the best catalytic performance for the N-alkylation of aniline with benzyl alcohol giving a quantitative conversion to N-benzylaniline in 3 h. Experimental and theoretical studies at the DFT level on the N-alkylation of aniline with benzyl alcohol catalysed by the model compound [IrCl(cod)(IMe)] (IMe = 1, 3-dimethyl-imidazol-2-ylidene) support the participation of the iridium catalyst not only in the alcohol dehydrogenation and imine hydrogenation steps but also in the key step leading to the formation of the new C-N bond. Nucleophilic attack of an iridium-amido species generated in basic medium on the electrophilic aldehyde results in a hemiaminolate intermediate species from which the hemiaminal is released by alcoholysis. The free hemiaminal dehydrates to give the corresponding intermediate imine product that is hydrogenated by the iridium catalyst to the N-alkylated amine product. The iridium(i) complexes featuring functionalised NHC ligands are more active than [IrCl(cod)(IMe)] which highlights the positive influence of the functional group on the N-alkylation catalytic activity

    On the Lebesgue measure of Li-Yorke pairs for interval maps

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    We investigate the prevalence of Li-Yorke pairs for C2C^2 and C3C^3 multimodal maps ff with non-flat critical points. We show that every measurable scrambled set has zero Lebesgue measure and that all strongly wandering sets have zero Lebesgue measure, as does the set of pairs of asymptotic (but not asymptotically periodic) points. If ff is topologically mixing and has no Cantor attractor, then typical (w.r.t. two-dimensional Lebesgue measure) pairs are Li-Yorke; if additionally ff admits an absolutely continuous invariant probability measure (acip), then typical pairs have a dense orbit for f×ff \times f. These results make use of so-called nice neighborhoods of the critical set of general multimodal maps, and hence uniformly expanding Markov induced maps, the existence of either is proved in this paper as well. For the setting where ff has a Cantor attractor, we present a trichotomy explaining when the set of Li-Yorke pairs and distal pairs have positive two-dimensional Lebesgue measure.Comment: 41 pages, 3 figure

    Roxborough park community wildfire evacuation drill: data collection and model benchmarking

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    Wildfires are increasing in scale, frequency and longevity, and are affecting new locations as environmental conditions change. This paper presents a dataset collected during a community evacuation drill performed in Roxborough Park, Colorado (USA) in 2019. This is a wildland-urban interface community including approximately 900 homes. Data concerning several aspects of community response were collected through observations and surveys: initial population location, pre-evacuation times, route use, and arrival times at the evacuation assembly point. Data were used as inputs to benchmark two evacuation models that adopt different modelling approaches. The WUI-NITY platform and the Evacuation Management System model were applied across a range of scenarios where assumptions regarding pre-evacuation delays and the routes used were varied according to original data collection methods (and interpretation of the data generated). Results are mostly driven by the assumptions adopted for pre-evacuation time inputs. This is expected in communities with a low number of vehicles present on the road and relatively limited traffic congestion. The analysis enabled the sensitivity of the modelling approaches to different datasets to be explored, given the different modelling approaches adopted. The performance of the models were sensitive to the data employed (derived from either observations or self-reporting) and the evacuation phases addressed in them. This indicates the importance of monitoring the impact of including data in a model rather than simply on the data itself, as data affects models in different ways given the modelling methods employed. The dataset is released in open access and is deemed to be useful for future wildfire evacuation modelling calibration and validation efforts.This study was supported by National Institute of Standards and Technology, U.S. Department of Commerce under award 60NANB18D255. The EMS was developed by the University of Cantabria within the ASSISTANCE project funded by the European Union’s H2020 research and innovation programme under grant agreement No. 832576

    Factores socioculturales y personales relacionados con el mensaje mediático del culto al cuerpo influyentes en el bienestar de los jóvenes

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    Este trabajo estudia los factores personales y socioculturales relacionados con el culto al cuerpo que pueden influir en el bienestar de los jóvenes. Se pretende agruparlos en dimensiones de influencia y profundizar en el papel de los medios de comunicación y sus mensajes, como elementos también relacionados con el culto al cuerpo. Se ha realizado un análisis multivariable con una muestra de 452 jóvenes y se han obtenido tres dimensiones socioculturales de influencia: “la dimensión social y personal”, “la sociocultural mediática” y “la de imágenes de culto al cuerpo”. Las diferencias en cuanto a su valoración difieren de forma significativa para hombres y mujeres

    Alkali activated materials based on fluid catalytic cracking catalyst residue (FCC): Influence ofSiO2/Na2O and H2O/FCC ratio on mechanical strength and microstructure

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    Reuse of industrial and agricultural wastes as supplementary cementitious materials (SCMs) in concrete and mortar productions contribute to sustainable development. In this context, fluid catalytic cracking catalyst residue (spent FCC), a byproduct from the petroleum industry and petrol refineries, have been studied as SCM in blended Portland cement in the last years. Nevertheless, another environmental friendly alternative has been conducted in order to produce alternative binders with low CO2 emissions. The use of aluminosilicate materials in the production of alkali-activated materials (AAMs) is an on going research topic which can present low CO2 emissions associated. Hence, this paper studies some variables that can influence the production of AAM based on spent FCC. Specifically, the influence of SiO2/Na2O molar ratio and the H2O/spent FCC mass ratio on the mechanical strength and microstructure are assessed. Some instrumental techniques, such as SEM, XRD, pH and electrical conductivity measurements, and MIP are performed in order to assess the microstructure of formed alkali-activated binder. Alkali activated mortars with compressive strength up to 80 MPa can be formed after curing for 3 days at 65 C. The research demonstrates the potential of spent FCC to produce alkali-activated cements and the importance of SiO2/Na2O molar ratio and the H2O/spent FCC mass ratio in optimising properties and microstructure.Authors would like to thank to the Ministerio de Ciencia e Innovacion (MICINN) of the Spanish Government (BIA2011-26947) and to FEDER for funding, and also to the PROPG - UNESP "Universidade Estadual Paulista Julio de Mesquita Filho'', Brazil.Mitsuuchi Tashima, M.; Akasaki, JL.; Melges, J.; Soriano Martínez, L.; Monzó Balbuena, JM.; Paya Bernabeu, JJ.; Borrachero Rosado, MV. (2013). Alkali activated materials based on fluid catalytic cracking catalyst residue (FCC): Influence ofSiO2/Na2O and H2O/FCC ratio on mechanical strength and microstructure. Fuel. 108:833-839. https://doi.org/10.1016/j.fuel.2013.02.052S83383910

    Efficacy and efficiency of a new therapeutic approach based on activity-oriented proprioceptive antiedema therapy (TAPA) for edema reduction and improved occupational performance in the rehabilitation of breast cancer-related arm lymphedema in women: a controlled, randomized clinical trial

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    Background: Breast cancer (BC) is a major public health issue. More than one out of five women treated for breast cancer will develop lymphedema in an upper extremity. Current evidence advocates transdisciplinary oncological rehabilitation. Therefore, research in this area is necessary since limited consensus having been reached with regard to the basic essential components of this rehabilitation. Consensus has, however, been reached on the use of decongestive lymphedema therapy (DLT), but due to a lack of tests, the necessary dosages are unknown and its level is moderately strong. This study attempts to verify both the efficacy of activity-oriented proprioceptive antiedema therapy (TAPA), as compared to conventional treatments such as DLT or Complex Physical Therapy (CPT), as well as its efficiency in terms of cost-effectiveness, for patients affected by breast cancer-related arm lymphedema. Methods: Controlled, randomized clinical trial with dual stratification, two parallel arms, longitudinal and single blind. 64 women with breast cancer-related arm lymphedema will take part in the study. The experimental group intervention will be the same for stage I and II, and will consist of neuro-dynamic exercises oriented to the activity, proprioceptive neuromuscular facilitation activities and proprioceptive anti-edema bandaging. The control group intervention, depending on the stage, will consist of preventive measures, skin care and exercise-prescribed training in the lymphedema workshop as well as compression garments (Stage I) or conservative Complex Decongestive Therapy treatment (skin care, multi-layer bandaging, manual lymphatic drainage and massage therapy) (Stage II). Results: Sociodemographic and clinical variables will be collected for the measurement of edema volume and ADL performance. Statistical analysis will be performed on intent to treat. Discussion: It has been recommended that patient training be added to DLT, as well as a re-designing of patient lifestyles and the promotion of health-related aspects. In addition, clinical trials should be undertaken to assess neural mobilization techniques and proprioceptive neuromuscular facilitation should be included in the therapy. Cohesive bandaging will also be performed as an early form of pressotherapy. The proposed study combines all of these aspects in order to increased comfort and promote the participation of individuals with lymphedema in everyday situations. Limitations: The authors have proposed the assessment of the experimental treatment for stages I and II. One possible limitation is the lack of awareness of whether or not this treatment would be effective for other stages as well as the concern for proper hand cleansing during use of bandages, given the current COVID-19 pandemic situation. Trial registration: This trial was registered in ClinicalTrials.gov (NCT03762044). Date of registration: 23 November 2018. Prospectively Registered

    Sustainable production of graphene-anchored NHC-iridium catalyst for water splitting by using coke-like wastes: Investigation of different chemical synthetic routes

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    The authors thank the Spanish Ministry of Science and innovation (MICINN) (PID2019-104028RB-I00) and Spanish council for research (icoop program, COOPB22006) for their financial support. Dr. M-González-Ingelmo acknowledges his fellowship from the Asturias regional Government (FICYT, Severo Ochoa Program BP20-168)
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