2 + 1 Highways: Overview and Future Directions

Most of the rural transportation system is composed of two-lane highways, and many of them serve as the primary means for rural access to urban areas and freeways. In some highways, traffic volumes can be not high enough to justify a four-lane highway but higher than can be served by isolated passing lanes, or can present high number of head-on collisions. In those conditions, 2 + 1 highways are potentially applicable. This type of highway is used to provide high-performance highways as intermediate solution between the common two-lane highway and the freeway. Successful experiences reported in Germany, Sweden, Finland, Poland, or Texas (US) may suggest that they are potentially applicable in other countries. The objective of this white paper is to provide an overview of the past practice in 2 + 1 highways and discuss the research directions and challenges in this field, specially focusing on, but not limited to, operational research in association with the activities of the Subcommittee on Two-Lane Highways (AHB40 2.2) of the Transportation Research Board. The significance of this paper is twofold: (1) it provides wider coverage of past 2 + 1 highways design and evaluation, and (2) it discusses future directions of this field.The authors wish to thank the Fundación Agustín de Betancourt from the Universidad Politécnica de Cartagena for funding the research

Cancioneros y codicología. Propuesta de un modelo de descripción codicológica

[Resumo] O estudo codicolóxico e paleográfico é o paso primeiro e fundamental para coñecer calquera manuscrito ou impreso. Neste artigo, sen pretensións de ser unha lección nova para expertos e avezados codicólogos e paleógrafos, elabórase o esquema dunha das posibles formas de se achegar ao estudo codicolóxico. Trátase dun esquema integrador doutros modelos e que aquí se ten aplicado exclusivamente a cancioneiros manuscritos do século XV, que teñen servido para exemplificar algún dos problemas concretos que presentan tanto a descrición interna como externa dos mesmos.[Resumen] El estudio codicológico y paleográfico es el paso primero y fundamental para conocer cualquier manuscrito o impreso. En este artículo, sin pretensiones de ser una lección nueva para expertos y avezados codicólogos y paleógrafos, se elabora el esquema de una de las posibles formas de acercarse al estudio codicológico. Se trata de un esquema integrador de otros modelos y que aquí se ha aplicado exclusivamente a cancioneros manuscritos del siglo XV, los cuales han servido para ejemplificar algunos problemas concretos que plantean tanto la descripción interna como externa de los mismos.[Abstract] The first step to approach to the study of any manuscript or print is the codicological and palaeographic study. The aim of this article is to offer a codicological scheme, which is not a new one, but one of the possible ways of approaching to the manuscript. The model has been applied in here exclusively to manuscript songbooks of the 15th century, which have served to exemplify some concrete problems that rise from the internal and external descriptions. KEYWORDS: songbooks, codicology, manuscripts, cancionero poetry

Competitive Advantages as a Complete Mediator Variable in Strategic Resources, Dynamic Capabilities and Performance Relations in the Car Sales Sector

Taking the resource-based view –RBV- and the dynamic capability view –DCV- as an orientation, the main aim of this study is to develop the mediator role that competitive advantages play in the relations between strategic resources, dynamic capabilities and performance. The study takes place in a dynamic and changing sector: the sale of new cars in Portugal. The results show that (a) achieving competitive advantages, which are decisive for business results, depends on the available strategic resources and the generating of dynamic capabilities, (b) in dynamic and changing sectors strategic resources are essential to generate dynamic capabilities, (c) firms must center their attention on, more than results, the generating of sustainable competitive advantages as these act as a mediator variable of the effect of strategic resources and dynamic capabilities on performance. The data scrutiny uses structural equation modeling (SEM) through PLS as the statistical instrument. The sample comprises 89 firms which sell new cars in Portugal

Pseudothionin-St1. A potato peptide active against potato pathogens.

A 5-kDa polypeptide, pseudothionin Solanum tuberosum 1(Pth-St1), which was active against Clavibacter michiganensis subspecies sepedonicus, a bacterial pathogen of potatoes, has been purified from the buffer-insoluble fraction of potato tubers by salt extraction and HPCL. Pth-St1 was also active against other potato pathogens tested (Pseudomonas solanacearum and Fusarium solani). The N-terminal amino acid sequence of this peptide was identical (except for a N/H substitution at position 2) to that deduced from a previously reported cDNA sequence (EMBL accession number X-13180), which had been misclassified as a Bowman-Birk protease inhibitor. Pth-St1 did not inhibit either trypsin or insect α-amylase activities, and, in contrast with true thionins, did not affect cell-free protein synthesis or β-glucuronidase activity. Northern-blot and tissue-print analyses showed that steady-state mRNA levels were highest in flowers (especially in petals), followed by tubers (especially in the epidermal cell layers and in leaf primordia), stems and leaves. Infection of leaves with a bacterial pathogen suspended in 10 mM MgCl2 switched off the gene, whereas mock inoculation with 10 mM MgCl2 alone induced higher mRNA levels

Precisiones sobre el vocabulario de la ciencia en Roma: criterios de identificación y análisis de los términos geométricos en latín

As is well known, an outstanding improvement has recently become in the study of the scientific and technical fields of Latin lexicon. However, it is necessary to set up clearly the criteria in order to identify and analyse the terms in Latin according to the progress reached by terminology as an autonomous science, specially in the last decades. The object of this article is to put forward an approach to these criteria in a specialized field like Geometry in Latin language. We suggest some criteria to determine when a word can be considered a term in this field, in what conditions it is used and in which discursive contexts. These criteria could be extended as well to other different Latin terminological fields

Microfluidic-based 3d fibroblast migration studies in biomimetic microenvironments

Cell migration in 3D is a fundamental process in many physiological and pathological phenomena. Indeed, migration through interstitial tissue is a multi-step process that turns out from the cell-ECM interaction. It is a dynamic and complex mechanism that depends on the physic-chemical balance between the cell and its surrounding. Early stage of deep dermal wound healing process is a relevant migratory example, in which the fibroblast is the epicenter: the recruitment of the fibroblasts -by chemotaxis of PDGF-BB- to the clotted wound occurs. Likewise, this work focuses on studying the major underlying mechanisms of 3D fibroblast migration and the main microenvironmental cues involved within. To do so, we have confined two physiologically relevant hydrogels, made of collagen and fibrin, within microfluidic platforms. Firstly, an integral comparative study of biophysical and biomechanical properties of both gels is presented. In these results, we have overcome the wide diversity of the existing data and special stress has been done in order to compare the microstructural arrangement, resistance to flow and elasticity. On the other hand, controlled chemical gradients have been generated and characterized within the microfluidic devices. Since biomolecules interact as purely diffusive factors or bound to the matrix proteins, in this work, distribution of PDGF-BB and TGF-ß1 across collagen and fibrin gels has been quantified. Finally, by taking advantage of the biophysico-chemical definition, we have characterized the migratory responses of human fibroblasts within the microsystems in the presence of a chemoattractant (PDGF-BB). Our results demonstrate that the local microarchitecture of the hydrogels determines the migratory properties of human fibroblasts in response to controlled chemotactic and haptotactic gradients, in a myosin II-dependent manner.La migración celular en 3D es fundamental en muchos fenómenos fisiológicos y patológicos. La migración, la cual resulta de la interacción célula-matriz, es un mecanismo dinámico y complejo que depende del equilibrio entre la célula y su entorno físico-químico. Concretamente, la etapa temprana del proceso de cicatrización de heridas profundas es un proceso migratorio ejemplar, en el cual el fibroblasto es el epicentro: se produce el reclutamiento de los fibroblastos -por quimiotaxis de PDGF-BB- del tejido circundante al coágulo. Este trabajo se centra en el estudio de los principales mecanismos subyacentes de la migración de fibroblastos en 3D y las principales señales microambientales involucradas en ella. Para ello, se han empleado modelos in vitro haciendo uso de plataformas microfluídicas para confinar dos hidrogeles fisiológicamente relevantes, compuestos por colágeno y fibrina. En primer lugar, se presenta un estudio comparativo integral de las propiedades biofísicas y biomecánicas de los hidrogeles. En estos resultados, se ha hecho especial hincapié en comparar la conformación microestructural, la resistencia al flujo de fluido y la elasticidad. Por otro lado, se han generado y caracterizado gradientes químicos dentro de los dispositivos. Puesto que las biomoléculas interactúan como factores puramente difusivos o adheridos a las proteínas de la matriz, en este trabajo se ha cuantificado la distribución de PDGF-BB y TGF-β1, en colágeno y fibrina. Finalmente, mediante esta definición físico-química, se ha caracterizado la respuesta migratoria de fibroblastos humanos dentro de los microdispositivos en presencia de un factor químico (PDGF-BB). Los resultados aquí mostrados demuestran que la microarquitectura local de los hidrogeles determina las propiedades migratorias de fibroblastos humanos en respuesta a gradientes quimiotácticos y haptotácticos, de manera dependiente de la miosina II

LA OTRO CARA. EXPERIMENTANDO CON CONTRAPUBLICIDAD EN EL GRAFITI

[ES] Ya desde bien pequeño desarrollé una especial sensibilidad hacia las injus - ticias y los abusos que se cometen contra lo más vulnerables, tal vez por haberlos sufrido en primera persona. Este proyecto nace de la necesidad de transmitir un conjunto de sensaciones. Sentimientos de rabia, pena o rebeldía que experimento cada vez que las personas que ocupan situaciones privilegiadas dentro de nuestra sociedad utilizan su poder para mejorar aun más su estatus a costa del sufrimiento de los demás. A través de la disciplina artística que llevo practicando desde hace más de 20 años, el grafiti, en combinación con los valores de la contrapublicidad, pretendo realizar una serie de pinturas murales ubicadas en la calle. De este modo busco combatir gráficamente a grandes marcas en el espacio público. Quiero que el espectador/consumidor reflexione sobre el papel que ocupan las corporaciones en nuestra sociedad y como nos afecta. Por otro lado, quie - ro remarcar con mi trabajo la importancia de la empatía y el respeto como pilares fundamentales para construir una sociedad más justa.Moreno García, M. (2016). LA OTRO CARA. EXPERIMENTANDO CON CONTRAPUBLICIDAD EN EL GRAFITI. http://hdl.handle.net/10251/76184.TFG

Prácticas agrarias sostenibles en la agricultura mediterránea para la reducción de la erosión, el cambio climático y la pérdida de biodiversidad

Como consecuencia de los grandes retos climáticos y medioambientales a los que se enfrenta actualmente la región mediterránea, las diferentes administraciones están generando políticas que buscan minimizar los impactos derivados de los mismos. El marco general de este ámbito en Europa lo marca el Pacto Verde Europeo (Green Deal), cuyas propuestas están íntimamente relacionadas con la agricultura. Debido a que la agricultura de la cuenca mediterránea, con un pasado de milenios, está profundamente relacionada con el clima en el que ha evolucionado desde tiempos históricos. En la actualidad, los cultivos mediterráneos están siendo afectados por grandes impactos ambientales generados por el ser humano, de carácter global, pero que son más evidentes a escala mediterránea. Esto es debido a que las condiciones climáticas propias de este clima, ya de por sí fisiológicamente exigentes para los seres vivos, se han visto recrudecidas por la acción humana. Acción que ha favorecido los procesos erosivos sobre el suelo, el aumento de temperaturas y la reducción de precipitaciones a través del cambio climático, así como la pérdida de biodiversidad y los servicios ecosistémicos asociados a ella. Está previsto que la nueva Política Agraria Común (PAC) sea reforzada en sus aspectos medioambientales y climáticos, en un nuevo marco regulativo, denominado arquitectura verde. En esta nueva arquitectura, los denominados eco-regímenes, van a constituirse en las herramientas de transformación hacia un sistema agrario más sostenible y competitivo. En la actualidad, a nivel nacional, se está trabajando en la concreción y definición de estos ecoregímenes, con el objetivo de incluir su versión final en la regulación de la futura PAC. Los siete eco-regímenes previstos están destinadas a dos grandes campos ambientales. Uno cuya motivación es la agricultura de carbono y otro más dirigido a la conservación medioambiental. Estos siete eco-regímenes, van a tener como base diferentes prácticas agrícolas sostenibles. Y, en concreto, tres de ellos se basan en prácticas que han sido estudiadas en la presente tesis doctoral: cubiertas inertes procedentes de los restos de poda del olivar, siembra directa en cultivos herbáceos y creación de márgenes multifuncionales mediante barbechos semillados establecidos junto a cultivos herbáceos. La erosión es uno de los principales problemas ambientales que afectan al suelo en los olivares. El primer artículo de la tesis doctoral (capítulo 2) ha tenido como objetivo estudiar el efecto sobre la protección frente a la erosión del suelo del olivar de tres manejos diferentes de los residuos de poda. La investigación se llevó a cabo en un olivar con una producción total de 0,39 kg m-2 de peso seco de residuos de poda cada 2 años. Estos restos de poda fueron picados y esparcidos en franjas de 2 m de ancho en tres manejos diferentes. Manejo A, con densidades de 1,56 kg m-2 distribuidas en todas las calles del olivar. El manejo B, con densidades de 3,12 kg m-2 distribuidas en la mitad de las calles del olivar. Y el manejo C, con densidades de 3,12 kg m- 2 distribuidas en la mitad de las calles del olivar, alternando esta aplicación cada 2 años con la otra mitad de las calles. La influencia de los residuos en la protección del suelo se ha medido a través de la evolución de tres parámetros de los residuos a lo largo de 4 años: degradación de la masa de residuos, porcentaje de cobertura del suelo y distribución espacial. Los resultados del estudio, han demostrado que el manejo C es el que mejor protege el suelo de la erosión en el olivar, al mantener una cobertura protectora sobre sus calles del superior al 40%, mientras que la homogeneidad que mantienen los restos sobre su superficie es el doble que si se distribuyen los restos de poda con la mitad de densidad en todas las calles. La Iniciativa 4x1000 pretende mitigar las emisiones antropogénicas de CO2 mediante el secuestro de carbono orgánico en el suelo (COS). Su principal objetivo es aumentar la cantidad de C en los suelos del mundo anualmente en un 0,4%. En el segundo artículo de la tesis doctoral (capítulo 3) se ha presentado una nueva metodología de estudio centrada en la consecución de los objetivos regionales de la Iniciativa 4x1000 mediante la aplicación potencial de la Siembra Directa (SD) en los cultivos anuales. Se ha basado en la modelización del secuestro de carbono (SC) mediante Carbon Benefit Project (CBP), una herramienta online gratuita que permite realizar una modelización de la evolución de los stocks de C y de las emisiones de Gases de Efecto Invernadero (GEI), derivadas del uso de diferentes sistemas de gestión del suelo. Para todo el ámbito de estudio (15 regiones de España), la media anual de SC para la SD respecto al laboreo convencional (CT) obtenida a través de CBP es de 0,38 Mg de C ha-1 año-1. Mientras que la cantidad potencial de SC correspondiente puede llegar a estar próxima a los 3 Tg de C al año. La comparación entre el C anual derivado de la aplicación de la SD y los contenidos en COS en los cultivos anuales, ha permitido calcular la importancia potencial de la SD, en el marco regional, de la Iniciativa 4x1000. Como resultado se ha observado que existen amplias zonas donde el C que se podría secuestrar anualmente podría ser 2 y hasta 3 veces superior al valor de referencia marcado por dicha iniciativa (0,04%). Lo que supone que la aplicación potencial de SD representaría un porcentaje importante de los objetivos totales de secuestro de C establecidos en la Iniciativa 4x1000 en Navarra (52%), Castilla-La Mancha (51%), Castilla y León (43%), Aragón (35%), La Rioja (35%), Andalucía (35%) y Cataluña (29%). Esta metodología de cálculo del potencial de la SD sobre la Iniciativa 4x1000 es fácilmente replicable en regiones y países de todo el mundo. Las tierras más aptas para el uso agrícola han sido ocupadas gradualmente por los cultivos en todo el mundo. Se han creado grandes e ininterrumpidas tierras de cultivo, al tiempo que se aplican en ellas cantidades desproporcionadas de fertilizantes, insecticidas, fungicidas y herbicidas. Como consecuencia, la actividad agrícola tiene un impacto negativo en la biodiversidad, por lo que se ha hecho necesaria la intensificación ecológica de las tierras cultivadas. Mediante la implantación de márgenes multifuncionales (MMF), se logra el establecimiento de márgenes de flora autóctona adyacentes a las tierras de cultivo, que proporcionan un hábitat seminatural que provee de alimentación y refugio de la fauna. En el tercer trabajo (capítulo 4) se estudiaron tres mezclas de especies diferentes sembradas en MMF. Se determinó la gran capacidad de las semillas de seis especies (Borago officinalis, Glebionis coronaria, Coriandrum sativum, Sinapis alba, Trifolium resupinatum y Vicia sativa) para proliferar con éxito en este tipo de infraestructuras verdes. Además, se observaron reducciones de hasta el 65% en la aparición de malas hierbas y aumentos del 36% en la biodiversidad de polinizadores en los MMF sembrados con respecto al MMF constituido por flora espontánea. La biodiversidad de la fauna epígea con respecto a la presente en los cultivos anuales, aumentó en un 15% en los márgenes de flora espontánea y en un 32% en los márgenes constituidos por plantas sembradas.As a result of the major climate and environmental challenges currently facing the Mediterranean region, the different administrations are generating policies that seek to minimise the impacts derived from these challenges. The general framework in this area in Europe is set by the European Green Deal, whose proposals are closely related to agriculture. Because agriculture in the Mediterranean basin, with a history stretching back millennia, is deeply linked to the climate in which it has evolved since historical times. Today, Mediterranean crops are being affected by major human-generated environmental impacts, which are global in nature, but which are most evident on a Mediterranean scale. This is due to the fact that the climatic conditions of this climate, already physiologically demanding for living beings, have been intensified by human action. This has favoured soil erosion, increased temperatures and reduced rainfall through climate change, as well as the loss of biodiversity and associated ecosystem services. The new Common Agricultural Policy (CAP) is expected to be strengthened in its environmental and climate aspects, in a new regulatory framework, the so-called green architecture. In this new architecture, the so-called eco-regimes will become the tools for transformation towards a more sustainable and competitive agricultural system. At national level, work is currently underway to specify and define these eco-regimes, with the aim of including their final version in the regulation of the future CAP. The seven eco-regimes envisaged are aimed at two main environmental fields. One is motivated by carbon farming and the other is aimed at environmental conservation. These seven eco-regimes will be based on different sustainable agricultural practices. Specifically, three of them are based on practices that have been studied in this doctoral thesis: inert covers from olive pruning waste, direct sowing in herbaceous crops and the creation of multifunctional margins through seeded fallows established next to herbaceous crops. Erosion is one of the main environmental problems affecting the soil in olive groves. The first article of the doctoral thesis (chapter 2) aimed to study the effect of three different pruning residue management practices on soil erosion protection in olive orchards. The investigation was carried out in an olive orchard with a total production of 0.39 kg m-2 dry weight of pruning residues every 2 years. These pruning residues were chopped and spread in 2 m wide strips in three different managements. Management A, with densities of 1.56 kg m-2 distributed in all the alleys of the olive grove. Management B, with densities of 3.12 kg m-2 distributed in half of the olive grove lanes. And management C, with densities of 3.12 kg m-2 distributed in half of the olive grove lanes, alternating this application every 2 years with the other half of the lanes. The influence of residues on soil protection has been measured through the evolution of three residue parameters over 4 years: degradation of the residue mass, percentage of soil cover and spatial distribution. The results of the study have shown that management C is the one that best protects the soil from erosion in the olive grove, by maintaining a protective cover over its lanes of more than 40%, while the homogeneity maintained by the residues over its surface is twice as high as if the pruning residues were distributed with half the density over all inter-rows. The 4x1000 Initiative aims to mitigate anthropogenic CO2 emissions through soil organic carbon sequestration (COS). Its main objective is to increase the amount of C in the world's soils annually by 0.4%. In the second article of the PhD thesis (chapter 3) a new study methodology has been presented focusing on the achievement of the regional targets of the 4x1000 Initiative through the potential application of no-tillage (NT) in annual crops. It is based on the modelling of carbon sequestration (CS) using the Carbon Benefit Project (CBP), a free online tool that allows modelling the evolution of C stocks and Greenhouse Gas (GHG) emissions, derived from the use of different soil management systems. For the whole study area (15 regions of Spain), the annual average of CS for DS compared to conventional tillage (CT) obtained through PBC is 0.38 Mg C ha-1 yr-1. Whereas the corresponding potential amount of CS can be close to 3 Tg C per year. The comparison between the annual C derived from the application of DS and the COS contents in annual crops has allowed to calculate the potential importance of DS in the regional framework of the 4x1000 Initiative. As a result, it has been observed that there are large areas where the C that could be sequestered annually could be 2 or even 3 times higher than the reference value set by this initiative (0.04%). This means that the potential application of DS would represent a significant percentage of the total C sequestration targets set by the 4x1000 Initiative in Navarra (52%), Castilla-La Mancha (51%), Castilla and Leon (43%), Aragon (35%), La Rioja (35%), Andalusia (35%) and Catalonia (29%). This methodology for calculating the potential of SD on the 4x1000 Initiative is easily replicable in regions and countries around the world. Land that is more suitable for agricultural use has gradually been taken over by crops all over the world. Large, uninterrupted croplands have been created, while disproportionate amounts of fertilisers, insecticides, fungicides and herbicides are applied. As a consequence, agricultural activity has a negative impact on biodiversity, and ecological intensification of cultivated land has become necessary. Through the establishment of multifunctional margins (MFM), the establishment of native flora margins adjacent to croplands is achieved, providing a semi-natural habitat that provides food and shelter for wildlife. In the third paper (chapter 4), three different species mixtures planted in MFM were studied. The seeds of six species (Borago officinalis, Glebionis coronaria, Coriandrum sativum, Sinapis alba, Trifolium resupinatum and Vicia sativa) were found to be highly capable of successfully proliferating in this type of green infrastructure. Furthermore, reductions of up to 65% in weed emergence and 36% increases in pollinator biodiversity were observed in the sown MFM compared to the MFM consisting of spontaneous flora. Biodiversity of epigean fauna compared to that present in annual crops increased by 15% in the spontaneous flora margins and by 32% in the sown plant margins

Mecanismos de iniciación de la traducción de los mRNAS del virus Sindbis

Tesis doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Biología Molecular. Fecha de lectura: 20-04-2015Alphaviruses are responsible for a variety of diseases, including some fatal encephalitis, in humans and other vertebrates. Sindbis virus (SINV) is a representative member of alphaviruses, which contain a positive single-stranded RNA as genome. In the early phase after infection, this genomic RNA is translated following a canonical mechanism, while a subgenomic mRNA (sgmRNA) directs the synthesis of viral structural proteins during the late phase of infection, when the translation of host cellular mRNAs has been shut-off. The mechanism by which this sgmRNA is translated under these conditions has been the object of intensive research during the past few years. In the present work we demonstrate that the eukaryotic initiation factor (eIF) 4A is not required to translate SINV sgmRNA in mammalian infected cells. However, eIF4A is required for efficient translation in cells transfected with in vitro synthesized sgmRNA. Therefore, this viral mRNA exhibits a dual mechanism for its translation. In addition, other eIFs including eIF4E or PABP may not participate in this process in infected cells. Furthermore, in this viral mRNA exists a hairpin structure (DLP) that confers eIF2, but not eIF4A independence. In sharp contrast to what is observed in mammalian cells, active eIF2 is necessary to translate SINV sgmRNA in insect cells, and the DLP does not confer any translational advantage. Nevertheless, eIF4A is dispensable for SINV sgmRNA translation in mosquito cells. These findings indicate that SINV sgmRNA translation requires different initiation factors in vertebrate and insect cells. Besides, we show that the translation mechanism of this mRNA involves the scanning of the 5’ untranslated region (5’- UTR) by the preinitiation complex in both cell lines. Moreover, we have constructed some viral mRNAs bearing two AUG initiation codons that respond differentially to eIF2 inactivation, indicating that AUG selection is dependent on the cellular context, the phosphorylation state of eIF2α and the presence of regulatory elements such as DLP. Collectively, these results suggest that translation of alphavirus sgmRNA follows a novel scanning mechanism to initiate translation and to select the correct AUG initiation codon, without the participation of crucial eIFs. Finally, we found a new motif, constituted by three repeated sequences, at the 3’-UTR that are necessary for the translation of both SINV genomic and subgenomic mRNAs in insect, but not in mammalian systems. Complementary sequences at the 5’-UTR also regulate SINV mRNA translation and transcription. Thus, these SINV repeated regions constitute the first example of a motif present at the 3’- UTR that provides translatability to mRNAs from an animal virus in a cell specific manner. In addition, these findings constitute a clue to better understand, at the molecular level, the evolution of alphaviruses and other arboviruses.El trabajo presentado en esta tesis doctoral ha sido realizado mediante la concesión de la beca FPI BES-2010- 039571 del Ministerio de Economía y Competitividad. Ha sido financiado por el proyecto BFU2009-07352 otorgado por la Dirección General de Investigación Científica y Técnica, Ministerio de Economía y Competitivida

Retrospective and Prospective Analysis on Educational Leadership: Indicators of Productivity, Dispersion, and Content

This article analyzes the production, performance, impact, and content of scientific documents contained in an internationally recognized database, the Web of Science, that consider educational leadership (EL) thesaurus (title, abstract and/or keywords). To this end, a scientometric study was performed on a sample of 2,181 research documents that met the established inclusion criteria. A co-word analysis was also performed using Hirsch’s index (2005), as well as several bibliometric indicators, impact factors, and citation indices (h, g, hg, and q2). The main findings indicate that production on the topic of EL dates back to 1924, although it did not reach a significant level until 2004. Several important points related to the production profile on EL are highlighted: language, area of knowledge and institutions, and authors specializing in the subject. There are several lines of study open in the established periods, and the subjects that should be taken into account in the future are “critical-race-theory,” “identity,” and “distributedleadership.” The implications and limitations of the study are discussed and ways for education leaders to address new education policies and their practical implications are provided.Ministry of Universities of the Government of SpainEuropean Commissio