Photometric and fundamental plane studies of galaxies

Determining the morphological parameters that describe galaxies has always been a challenging task. The studies on the correlations between different photometric as well as spectroscopic parameters of the galaxies help in understanding their structure, properties of the stars and gas which constitute the galaxy, the various physical and chemical processes which determine the properties, and galaxy formation and evolution. In the last few decades, the advent of Charge Coupled Devices (CCDs) and near infrared arrays ha\·e provided quick and reliable digitized data acquisition, in the optical and near infrared bands. This has provided an avalanche of data, which can be processed using sophisticated image analysis techniques to obtain information about the morphology of galaxies. The photometric analysis performed in this thesis involve the extraction of structural parameters of early type gala.xies imaged in the near infrared K (2.2ttm) band, obtaining correlations between these, parameters and using them to constrain the large scale properties of galaxi,~s.

Reduced L_1 level width and Coster-Kronig yields by relaxation and continuum interactions in atomic zinc

Calculations of the level width \gamma( L_1) and the f_12 and f_13 Coster-Kronig yields for atomic zinc have been performed with Dirac-Fock wave functions. For \gamma(L_1), a large deviation between theory and evaluated data exists. We include the incomplete orthogonality of the electron orbitals as well as the interchannel interaction of the decaying states. Orbital relaxation reduces the total rates in all groups of the electron-emission spectrum by about 10-20 %. Different, however, is the effect of the continuum interaction. The L_1-L_23X Coster-Kronig part of the spectrum is definitely reduced in its intensity, whereas the MM and MN spectra are slightly enhanced. This results in a reduction of Coster-Kronig yields, where for medium and heavy elements considerable discrepancies have been found in comparison to relativistic theory. Briefly, we discuss the consequences of our calculations for heavier elements.

Atomistic-continuum modeling of ultrafast laser-induced melting of silicon targets

In this work, we present an atomistic-continuum model for simulations of ultrafast laser-induced melting processes in semiconductors on the example of silicon. The kinetics of transient non-equilibrium phase transition mechanisms is addressed with MD method on the atomic level, whereas the laser light absorption, strong generated electron-phonon nonequilibrium, fast heat conduction, and photo-excited free carrier diffusion are accounted for with a continuum TTM-like model (called nTTM). First, we independently consider the applications of nTTM and MD for the description of silicon, and then construct the combined MD-nTTM model. Its development and thorough testing is followed by a comprehensive computational study of fast nonequilibrium processes induced in silicon by an ultrashort laser irradiation. The new model allowed to investigate the effect of laser-induced pressure and temperature of the lattice on the melting kinetics. Two competing melting mechanisms, heterogeneous and homogeneous, were identified in our big-scale simulations. Apart from the classical heterogeneous melting mechanism, the nucleation of the liquid phase homogeneously inside the material significantly contributes to the melting process. The simulations showed, that due to the open diamond structure of the crystal, the laser-generated internal compressive stresses reduce the crystal stability against the homogeneous melting. Consequently, the latter can take a massive character within several picoseconds upon the laser heating. Due to the large negative volume of melting of silicon, the material contracts upon the phase transition, relaxes the compressive stresses, and the subsequent melting proceeds heterogeneously until the excess of thermal energy is consumed. A series of simulations for a range of absorbed fluences allowed us to find the threshold fluence value at which homogeneous liquid nucleation starts contributing to the classical heterogeneous propagation of the solid-liquid interface. A series of simulations for a range of the material thicknesses showed that the sample width we chosen in our simulations (800 nm) corresponds to a thick sample. Additionally, in order to support the main conclusions, the results were verified for a different interatomic potential. Possible improvements of the model to account for nonthermal effects are discussed and certain restrictions on the suitable interatomic potentials are found. As a first step towards the inclusion of these effects into MD-nTTM, we performed nanometer-scale MD simulations with a new interatomic potential, designed to reproduce ab initio calculations at the laser-induced electronic temperature of 18946 K. The simulations demonstrated that, similarly to thermal melting, nonthermal phase transition occurs through nucleation. A series of simulations showed that higher (lower) initial pressure reinforces (hinders) the creation and the growth of nonthermal liquid nuclei. For the example of Si, the laser melting kinetics of semiconductors was found to be noticeably different from that of metals with a face-centered cubic crystal structure. The results of this study, therefore, have important implications for interpretation of experimental data on the kinetics of melting process of semiconductors.

El continuum mente-cerebro : procesos sensoriales

Este libro es el resultado, no sólo de años de intensa actividad investigativa, sino también de la necesaria reflexión asociada, por parte de científicos de la neurociencia y de filósofos de distintas nacionalidades quienes, en un fructífero encuentro efectuado en Madrid, España, dieron un paso crucial en la construcción del arco conceptual que vincula, por no decir identifica, la actividad cerebral con la mente propiamente dicha. En consideración a la relevancia de la obra para nuestra comunidad científica, la Universidad del Rosario, fiel a su convicción de brindar apoyo e incentivar la divulgación del conocimiento, decidió participar por intermedio de su Centro Editorial en la publicación de esta primera edición en idioma español, con la certeza de estar contribuyendo al desarrollo de la investigación, mediante la difusión de los hallazgos en este importante y aun no conocido a cabalidad campo de la ciencia.

Age Continuum essay podcast

Participators Trevor Kettle and Yvonne Middlewick

Age continuum presentation podcast

Participators Trevor Kettle and Yvonne Middlewick

Adolescentes em situação de vulnerabilidade social e o continuum risco-proteçãoriesgo-protección

Este es un estudio de casos múltiples realizado después de la inserción ecológica de los investigadores en los contextos de desarrollo de cuatro adolescentes en situación de vulnerabilidad social. Estos fueron seleccionados de un estudio más amplio llevado a cabo con 98 adolescentes de Brasil de dos grupos diferentes (G1 en situación de calle, y G2 en condición de extrema pobreza). Los adolescentes seleccionados tenía las calificaciones más altas y las más bajas de ajuste en sus respectivos grupos. Los cuatro jóvenes fueron descritos en cuanto a indicadores de ajuste, factores de riesgo y factores de protección, utilizando datos cuantitativos y datos del diario de campo. Los resultados mostraron puntos comunes y divergentes entre los casos y la existencia de un continuo de vulnerabilidad social. Este se relaciona más con la forma en que factores de riesgo y protección interactúan en la vida de cada adolescente, que con el contexto en el que viven (calle o familia).

El continuum autoimatge, imatge del centre, imatge de l'educació. 'El continuum autoimagen, imagen del centro, imagen de la educación'.

Es importante mantener un buen clima entre los profesores, pero también crear complicidades con los padres y los alumnos. Hace falta, pues, tener valores y comunicarlos adecuadamente, por lo cual es necesario cuidar las diversas imágenes de la escuela, especialmente la autoimagen profesional. Pero eso no surge espontáneamente: se debe crear, tractar, defender y comunicar nuestra realidad como profesionales y como institución de forma que el entorno nos muestre una imagen positiva y motivadora.

How to assess children's literacy, literacy developmental continuum. 'Cómo evaluar la alfabetización de los niños, alfabetización del desarrollo continuo'.

Es un instrumento de diagnóstico que permite a los profesores vincular la evaluación con la enseñanza, al proporcionar el mapa del recorrido de un niño en su etapa de aprendizaje del lenguaje oral y escrito. Es decir, es utilizado para evaluar y supervisar los progresos de los alumnos de párvulos a lo largo de los siguientes años de escolarización y, da una visión general del nivel alcanzado por éstos, así como, información sobre sus aptitudes hacia la lectura, la escritura y la comprensión.

The Continuum guide to geography education.

Esta guía, ordenada de forma alfabética, comprende los conceptos clave, los recursos, resultados de investigaciones, movimientos, cuestiones, debates, educadores y organizaciones que caracterizan la enseñanza de la geografía. Por lo cual, constituye un recurso tanto para los profesores de geografía como para los alumnos.

Por el reconocimiento universal de la libertad de identificación colectiva como un continuum entre ciudadanía y cosmopolitismo.

Dentro de la educación multicultural se hace necesario exponer el enfoque anti-racista, multicultural e intercultural en el marco de una acción colectiva que afirme unos valores y reglas de comportamiento donde se asiente una sociedad democrática y respetuosa con los derechos del hombre y de los pueblos. Para ello, se analizan las identidades colectivas diversas y sus dinámicas. Se realiza un análisis de la proliferación y de las variaciones de las identidades colectivas identificables en las sociedades europeas, con el fin de proponer una perspectiva de educación multicultural, centrada en el reconocimiento universal de la libertad de identificación colectiva como un continuum entre ciudadanía y cosmopolitismo.

First CRDS-measurements of water vapour continuum in the 940nm absorption band

Measurements of near-infrared water vapour continuum using continuous wave cavity ring down spectroscopy (cw- CRDS) have been performed at around 10611.6 and 10685:2 cm1. The continuum absorption coefficients for N2- broadening have been determined for two temperatures and wavenumbers. These results represent the first near-IR continuum laboratory data determined within the complex spectral environment in the 940nm water vapour band and are in reasonable agreement with simulations using the semiempirical CKD formulation.

Evaluation of suitable spectral intervals for near-IR laboratory detection of water vapour continuum absorption

The water vapour continuum absorption is an important component of molecular absorption of radiation in atmosphere. However, uncertainty in knowledge of the value of the continuum absorption at present can achieve 100% in different spectral regions leading to an error in flux calculation up to 3-5 W/m2 global mean. This work uses line-by-line calculations to reveal the best spectral intervals for experimental verification of the CKD water vapour continuum models in the currently least studied near-infrared spectral region. Possible sources of errors in continuum retrieval taken into account in the simulation include the sensitivity of laboratory spectrometers and uncertainties in the spectral line parameters in HITRAN-2004 and Schwenke-Partridge database. It is shown that a number of micro-windows in near-IR can be used at present for laboratory detection of the water vapour continuum with estimated accuracy from 30 to 5%.

Pure water vapor continuum measurements between 3100 and 4400 cm1: Evidence for water dimer absorption in near atmospheric conditions

Despite the potentially important role that water dimers may play in the Earth’s energy balance, there is still a lack of firm evidence for absorption of radiation by dimers in near-atmospheric conditions. We present results of the first high-resolution laboratory measurements of the water vapor continuum absorption within the 3100–4400 cm1 spectral region at a range of near-room temperatures. The analysis indicates a large contribution of dimer absorption to the water vapor continuum, significantly in excess of that predicted by other modern representations of the continuum. The temperature dependence agrees well with that expected for dimers.