Wind and boundary driven planetary geostrophic circulation in a polar basin

PhD ThesisThe Arctic Ocean circulation is controlled by the interaction of many factors such as bathymetry, wind stress and volume transport across the straits connecting the basin to its marginal seas. In addition, stratification plays an important role in the 3–dimensional circulation, shielding the deep warm, salty water of Atlantic origin from the surface cold, relatively fresh layer. However, it is not clear how these factors interact together and how their relative contribution to the circulation will change as the Arctic warms. This thesis focuses on a subset of the factors determining the circulation of the Arctic. We confine our attention to homogeneous wind and boundary forced flows in a polar basin with a range of idealised topographies. New analytical solutions using a beta–sphere approximation first proposed by Imawaki and Takano (1974) are obtained for boundary and wind forced planetary geostrophic circulation. These solutions are compared with equivalent numerical solutions using the NEMO modelling system to evaluate the fidelity of the beta–sphere approximation. Then, numerical solutions are determined for planetary geostrophic flow in basins more representative of the Arctic, containing a transpolar ridge and variable width continental shelves. We found the role of shelf break currents connecting the straits is ubiquitous. A new dispersion relation for planetary waves is derived on the beta–sphere and compared with the equivalent dispersion relation on the polar plane (LeBlond, 1964). The thesis also examines numerical time dependent solutions of the unsteady circulation driven by harmonically perturbation transport varying in time across one (typically the Bering) of three straits. Vorticity waves then determine the evolution of the resulting sea surface height anomaly field. It is demonstrated that a non–uniform width shelf fundamentally controls the partition of the circulation between the Davis and Nordic Strait when the Bering Strait transport is perturbed. The final chapter of the thesis briefly sums up the most important results obtained in this study

Mantle formation, coagulation and the origin of cloud/core-shine: II. Comparison with observations

Many dense interstellar clouds are observable in emission in the near-IR, commonly referred to as "Cloudshine", and in the mid-IR, the so-called "Coreshine". These C-shine observations have usually been explained with grain growth but no model has yet been able to self-consistently explain the dust spectral energy distribution from the near-IR to the submm. We want to demonstrate the ability of our new core/mantle evolutionary dust model THEMIS (The Heterogeneous dust Evolution Model at the IaS), which has been shown to be valid in the far-IR and submm, to reproduce the C-shine observations. Our starting point is a physically motivated core/mantle dust model. It consists of 3 dust populations: small aromatic-rich carbon grains; bigger core/mantle grains with mantles of aromatic-rich carbon and cores either made of amorphous aliphatic-rich carbon or amorphous silicate. We assume an evolutionary path where these grains, when entering denser regions, may first form a second aliphatic-rich carbon mantle (coagulation of small grains, accretion of carbon from the gas phase), second coagulate together to form large aggregates, and third accrete gas phase molecules coating them with an ice mantle. To compute the corresponding dust emission and scattering, we use a 3D Monte-Carlo radiative transfer code. We show that our global evolutionary dust modelling approach THEMIS allows us to reproduce C-shine observations towards dense starless clouds. Dust scattering and emission is most sensitive to the cloud central density and to the steepness of the cloud density profile. Varying these two parameters leads to changes, which are stronger in the near-IR, in both the C-shine intensity and profile. With a combination of aliphatic-rich mantle formation and low-level coagulation into aggregates, we can self-consistently explain the observed C-shine and far-IR/submm emission towards dense starless clouds.Comment: Paper accepted for publication in A&A with companion paper "Mantle formation, coagulation and the origin of cloud/core-shine: I. Dust scattering and absorption in the IR", A.P Jones, M. Koehler, N. Ysard, E. Dartois, M. Godard, L. Gavila

Employer brand attraction: key factors to attract talent

Una marca empleadora sólida comienza por atraer talento. Ser capaces de atraer a los mejores, a los más brillantes, y a quienes tengan mayor capacidad para integrarse en la organización es el primer paso para lograr uno de los objetivo de la marca empleadora. Por este motivo interesa conocer desde la perspectiva de los candidatos ¿cuáles son los atributos que dotan de atractivo a una marca empleadora? En esta investigación se exploran cuáles son los factores que mejor explican el atractivo de las marcas empleadoras entre los recién licenciados españoles, un segmento especialmente interesante para las organizaciones. Partiendo de un enfoque tridimensional del concepto de atractivo –conocimiento de la marca, atributos de su imagen y la expectativa de vivir determinadas experiencias laborales con la futura marca empleadora– diseñamos un cuestionario que recogía un conjunto de ítems basados en la literatura. Un análisis factorial exploratorio reveló los factores subyacentes a cada dimensión. Se concluye que para el perfil de candidatos estudiado, una marca empleadora es atractiva si también lo es comercialmente, si proyecta una imagen humanizada y promete una experiencia laboral estimulante.A solid employer brand starts by attracting talent. Being able to attract the best minds, the brightest candidates, and those with the highest ability to fully integrate in the organization is the first step to achieve the objective of employer branding. For this reason it is interesting to know which attributes contribute to perceive an employer brand as attractive, from the candidate´s perspective. This paper explores the factors that better explain the employer brand attractiveness among the Spanish recent graduates, a segment of special interest for organizations. Based on a three-dimensional approach of the concept attraction - brand knowledge, attributes of image and the expectation of living certain experiences when joining the employer brand- we designed a questionnaire containing a set of items based in existing literature. An exploratory factor analysis revealed the underlying factors of each dimension. We conclude that for the studied profile of candidates an employer brand is attractive if it is as well attractive from a commercial point of view, if it projects a humanized face and promises a stimulant labor experience.Unidad Dptal. de Organización de Empresas y MarketingFac. de Ciencias de la InformaciónFALSEpu

Utilización y valoración de textos académicos en la docencia de Teoría e Historia de la Educación

Diversos estudios han evidenciado que los alumnos, en la educación universitaria, utilizan cada vez con menor frecuencia, materiales bibliográficos en su aprendizaje. Por ello, pensamos que es necesario identificar los factores que motivan este hecho para plantear acciones que permitan superar dichas dificultades. Muchas veces los profesores no somos conscientes de que analizar un texto consiste en implementar un conjunto de operaciones cognitivas que los alumnos no saben cómo realizar. Los objetivos de estudio son: identificar las dificultades de la lectura de textos académicos y científicos de los estudiantes de la Facultad de Educación, conocer las actividades que el docente realiza para fomentar competencias lectoras y promover estrategias de lectura en el aula. En la investigación, se han planteado dos cuestionarios de preguntas cerradas y abiertas a una muestra de 89 alumnos que cursan la asignatura de Teoría e Historia de la Educación. Concretamente se les preguntó en torno a las dificultades respecto a la comprensión de los textos, y a las acciones complementarias que realiza el profesorado para entender el material bibliográfico sugerido. Los resultados señalan que los estudiantes tienen dificultades para su comprensión y que muchas veces no disponen de información adicional que les permita entender lo que leen

An approach to the strategic diagnosis of the equality of opportunities of gender in Higher Education in Spanish America

Esta investigación tiene como objetivo realizar el diagnóstico estratégico de la igualdad de oportunidades en la educación superior en Hispanoamérica. A partir de la base de que la universidad es el contexto desde el cual se puede transformar la sociedad, en la búsqueda de la igualdad de género y desde donde se pueden gestionar sociedades democráticas. Los datos han sido recopilados en seis universidades hispanoamericanas: Universidad Iberoamericana, Paraguay; Universidad Nacional de San Agustín, Perú; Universidad del Valle, Colombia; Universidad de Santo Tomás, Colombia; Universidad Mayor de San Simón, Bolivia y Universidad Mayor de San Andrés, Bolivia. Según las categorías que surgieron en cada universidad, y a partir de una encuesta aplicada a profesoras y profesores que ocupan cargos académicos y administrativos, hemos realizado el análisis DAFO para determinar las debilidades, fortalezas, oportunidades y amenazas. Realizamos la matriz de evaluación de los factores externos e internos, hicimos un análisis de las estrategias de desarrollo y elaboramos la matriz del balance de fuerzas con las estrategias elegidas. El análisis y discusión de los resultados nos ha permitido concluir que es necesario diseñar e implementar unidades de igualdad en las universidades participantes en nuestro estudio. Estas deben constituir redes colaborativas, de trabajo y de investigación en la perspectiva de la igualdad de oportunidades.The objective of this research is to make a strategic diagnosis of the equality of opportunities in the Higher Education of Spanish America, taking into account that the university is the basis for transformation of society when searching for equality of gender and from where democratic societies can be created. The data were obtained from six Spanish American universities: Universidad Iberoamericana (Paraguay), Universidad Nacional de San Agustín (Peru), Universidad del Valle (Colombia), Universidad Santo Tomás (Colombia), Universidad Mayor de San Andrés (Bolivia) and Universidad San Simón (Bolivia). According to the categories suggested by each university and based on a survey made to male and female professors with academic and administrative positions, we performed the DAFO analysis to determine the weaknesses, strengths, opportunities and threats. We made the matrix of evaluation of external and internal factors, an analysis of the development strategies and the matrix of balance of forces with the chosen strategies. The analysis and discussion of the results has allowed us to conclude that it is necessary to design and implement Equality Units in the participating universities; these universities must create collaborative work and research networks under the perspective of equality of opportunities.Artículo que presenta los resultados finales del diagnóstico estratégico sobre igualdad de oportunidades de género y que fue auspiciado por la Universidad de Alicante, España

Calidad y desarrollo profesional del profesorado universitario, desde la perspectiva de las comunidades de aprendizaje

En esta investigación, reflexionamos en torno a las competencias docentes que debe tener el profesor universitario desde la perspectiva de las comunidades de aprendizaje, en cada una de las etapas de la gestión del proceso de enseñanza-aprendizaje: 1) planificación y diseño de la docencia, donde se plantean competencias y objetivos, se organizan los contenidos, se eligen los materiales y recursos, y se formula la evaluación; 2) la puesta en acción de lo planificado, previamente (metodología y el uso de estrategias pedagógicas como la motivación y la tutorización); el uso adecuado de medios y materiales; la evaluación, que promueva la reflexión y desarrolle la capacidad crítica; y 3) desarrollo profesional (formación continua), que le proporcione al docente un dominio de la disciplina científica que imparte, y que le posibilite integrar las tecnologías de la información y de la comunicación en la docencia.In this research, we reflect about the teaching skills that a university professor should have from the perspective of learning communities at each stage of the management process of teaching and learning: 1) planning and design of teaching where competencies and objectives are set, contents are organized, materials and resources are chosen, and the assessment is made, 2) the implementation of the planned action (methodology and use of teaching strategies such as motivation and tutoring), the appropriate use of media and materials, evaluation, to promote and develop the critical thinking ability, and 3) professional development (continuing education) , to provide teachers a domain of scientific discipline to integrate information technology and communication in teaching

Modeling long term Enhanced in situ Biodenitrification and induced heterogeneity in column experiments under different feeding strategies

Enhanced In situ Biodenitrification (EIB) is a capable technology for nitrate removal in subsurface water resources. Optimizing the performance of EIB implies devising an appropriate feeding strategy involving two design parameters: carbon injection frequency and C:N ratio of the organic substrate nitrate mixture. Here we model data on the spatial and temporal evolution of nitrate (up to 1.2 mM), organic carbon (ethanol), and biomass measured during a 342 day-long laboratory column experiment (published in Vidal-Gavilan et al., 2014). Effective porosity was 3% lower and dispersivity had a sevenfold increase at the end of the experiment as compared to those at the beginning. These changes in transport parameters were attributed to the development of a biofilm. A reactive transport model explored the EIB performance in response to daily and weekly feeding strategies. The latter resulted in significant temporal variation in nitrate and ethanol concentrations at the outlet of the column. On the contrary, a daily feeding strategy resulted in quite stable and low concentrations at the outlet and complete denitrification. At intermediate times (six months of experiment), it was possible to reduce the carbon load and consequently the C:N ratio (from 2.5 to 1), partly because biomass decay acted as endogenous carbon to respiration, keeping the denitrification rates, and partly due to the induced dispersivity caused by the well developed biofilm, resulting in enhancement of mixing between the ethanol and nitrate and the corresponding improvement of denitrification rates. The inclusion of a dual-domain model improved the fit at the last days of the experiment as well as in the tracer test performed at day 342, demonstrating a potential transition to anomalous transport that may be caused by the development of biofilm. This modeling work is a step forward to devising optimal injection conditions and substrate rates to enhance EIB performance by minimizing the overall supply of electron donor, and thus the cost of the remediation strategy.Peer ReviewedPostprint (author's final draft

Uncertainties in gas kinematics arising from stellar continuum modelling in integral field spectroscopy data: the case of NGC2906 observed with MUSE/VLT

We study how the use of several stellar subtraction methods and line fitting approaches can affect the derivation of the main kinematic parameters (velocity and velocity dispersion fields) of the ionized gas component. The target of this work is the nearby galaxy NGC 2906, observed with the MUSE instrument at Very Large Telescope. A sample of twelve spectra is selected from the inner (nucleus) and outer (spiral arms) regions, characterized by different ionization mechanisms. We compare three different methods to subtract the stellar continuum (FIT3D, STARLIGHT and pPXF), combined with one of the following stellar libraries: MILES, STELIB and GRANADA+MILES. The choice of the stellar subtraction method is the most important ingredient affecting the derivation of the gas kinematics, followed by the choice of the stellar library and by the line fitting approach. In our data, typical uncertainties in the observed wavelength and width of the H\alpha and [NII] lines are of the order of _rms \sim 0.1\AA\ and _rms \sim 0.2\AA\ (\sim 5 and 10km/s, respectively). The results obtained from the [NII] line seem to be slightly more robust, as it is less affected by stellar absorption than H\alpha. All methods considered yield statistically consistent measurements once a mean systemic contribution \Delta\bar\lambda=\Delta\bar\sigma=0.2xDelta_{MUSE} is added in quadrature to the line fitting errors, where \Delta_{MUSE} = 1.1\AA\ \sim 50 km/s denotes the instrumental resolution of the MUSE spectra. Although the subtraction of the stellar continuum is critical in order to recover line fluxes, any method (including none) can be used in order to measure the gas kinematics, as long as an additional component of 0.2 x Delta_MUSE is added to the error budget.Comment: 20 pages, 14 figure