Bose-Einstein Condensation in a Double-Well System

The two-site version of the Bose-Hubbard model can be used as a simplified model of N bosons confined to two quantum wells. We study the behavior of low-temperature Bose-Einstein condensates as a function of the strength of the repulsive interactions between the bosons and of the size of the quantum-mechanical tunneling between the quantum wells. The ground-state of weakly interacting bosons tends to be one in which almost all particles are in the same quantum-mechanical state (‘Bose-Einstein Condensate’, or ‘BEC’). It is found that even very small amounts of interwell tunneling lead to a BEC, but that zero tunneling leads to two separate BECs, one in each well (‘fragmentation’). We study systematically the transition between a single BEC comprised of bosons in both wells, and a fragmented condensate consisting of two BECs, one for each well. Our analysis will use matrix computational methods to solve the Schrödinger equation of the two-well boson system, and obtain the energies and wavefunctions as eigenvalues and eigenvectors of the Hamiltonian matrix. We will compare the results obtained with previous analyses, and against analytical approximations developed for the limiting case of a large number of bosons (large N)

Coastal vulnerability assessment of Co. Dublin and Co. Wicklow to impacts of sea-level rise

This research identified the coastal areas of Counties Dublin and Wicklow most vulnerable to impacts of sea-level rise through the analysis of various indicators to provide an index-based assessment. Future vulnerability to potential impacts was also investigated. A primary challenge in understanding coastal exposure to water-level change was quantifying the important characteristics that make it susceptible to change over the next century. The bulk of the work comes from identification, compilation and quality control of indicators of coastal change, which in this area were found to be regional coastal slope, aspect, geomorphology, cliff type, mean tidal range, shoreline changes, mean significant wave height and relative sea-level rise. A case study to complement shoreline change evaluation was also carried out in south Co. Dublin using multi-temporal digital elevation models to assess volumetric changes on highly responsive, soft unconsolidated cliffs. High resolution 2D mapping was conducted from two CVI indexed-based maps using six and eight variables. The map showed levels of vulnerability from low to high assigned to different segments depending on their potential susceptibility to physical changes as water levels rise (exposure, sensitivity and adaptive capacity). The CVI showed that high vulnerability areas predominate in the southern areas from Arklow to Greystones. PCA analysis identified the main contributions as coming from cliff type and geomorphology, followed by wave and tidal range and lastly slope, and aspect, with minor contributions from shoreline change. Future sea level scenarios were derived from local, regional and global trends. A likely scenario showed estimates between 78 and 127cm. An upper limits projection of sea-level rise of 198cm for 2100 was derived for the worst case scenario. These estimates were used to asses the exposure of area to potential flooding when combining tide-surge water levels with local projected sea-level for 2040, 2060, 2080 and 2100. Maximum extreme water levels of 5.76m (0.5% AEP) and 5.67m and 5.58m OD Malin (1% and 2% AEP), were found by 2100. Two hotspots to the effects of future sea-level rise and storminess were identified in North Dublin (Bull Island and Sutton) and Wicklow from both current and future vulnerability assessments. A consistent methodology, within a well-defined conceptual framework and the development of a robust specific metric and accuracy of data, was crucial. Adapted methodologies used in this research provide a reference for future development of Irish coastal vulnerability maps nationwide. The work will enable policy makers and stakeholders to easily identify vulnerable areas and target investment for adaptation within realistic timeframes

Income Inequality and Economic Growth

[Abstract]: The effects of income inequality on economic growth and its relationship have been widely studied in recent decades. Most of the studies using cross-sectional data demonstrate a negative relationship between income inequality and economic growth. In this paper, we will study this relationship in the context of an extended neoclassical growth model of Mankiw, Romer and Weil (1992), following the baseline empirical model as described by De Dominicis et al. (2008). Using cross-sectional data we make estimations on a world sample of 94 countries for the period 1985 – 2017, which is divided into subsamples according to their level of income (high, middle and low). In order to do this, using the programming software R we built a data bank from the World Bank Database, Penn World Tables 9.1 and the Standardized World Income Inequality Database 8.2, and performed the whole econometric analysis of this paper. Some of our explanatory variables, such as the level of investment and initial income per capita resulted to be highly significant. This result is robust in all our subsamples and consistent with the empirical literature. However, regarding the relationship of income inequality and economic growth, we obtain a positive and statistically significant relationship between income inequality and economic growth in low-income countries, and a negative but statistically insignificant relationship for high and middle-income countries.[Resumen]: Los efectos de la desigualdad de ingresos en el crecimiento económico y su relación han sido ampliamente estudiados en las últimas décadas. La mayoría de los estudios que utilizan datos transversales demuestran una relación negativa entre la desigualdad de ingresos y el crecimiento económico. En este artículo, se estudia esta relación en el contexto de un modelo de crecimiento neoclásico extendido de Mankiw, Romer y Weil (1992), siguiendo el modelo empírico de referencia descrito por De Dominicis et al. (2008) Utilizando datos transversales, se realizan estimaciones en una muestra mundial de 94 países para el período 1985 - 2017, que se divide en submuestras según su nivel de ingresos (alto, medio y bajo). Para hacer esto, utilizando el software de programación R, se ha creado un banco de datos a partir de la Base de datos del Banco Mundial, las Penn World Tables 9.1 y the Standardized World Income Inequality Database 8.2, asi como el análisis econométrico completo de este estudio. Algunas de nuestras variables explicativas, como el nivel de inversión y el ingreso inicial per cápita resultaron ser altamente significativas. Este resultado es robusto en todas nuestras submuestras y consistente con la literatura empírica. Sin embargo, con respecto a la relación entre la desigualdad de ingresos y el crecimiento económico, obtenemos una relación positiva y estadísticamente significativa entre la desigualdad de ingresos y el crecimiento económico en los países de bajos ingresos, y una relación negativa pero estadísticamente insignificante para los países de ingresos altos y medianos.Traballo fin de grao (UDC.ECO). Economía. Curso 2019/2

Identification and partial purification of K88ab Escherichia coli receptor proteins in porcine brush border membranes

Six receptor proteins, with molecular masses ranging from 94 to 27 kDa, that bind to Escherichia coli K88ab fimbriae were recovered from brush border membranes and were detected after solubilization with Triton X-114. The recovery of these receptor proteins in the aqueous phase suggests their peripheral localization. The 63-, 60- and 33-kDa K88ab binding proteins were recovered using gel-filtration chromatography of the aqueous phase

Crítica de la teoría de la elección racional : esquema administrativo de competencia y cooperación

1 archivo PDF (14 páginas). magyecccRESUMEN: La presente investigación versa sobre como la noción de racionalidad, del individuo representativo de la teoría de la elección racional, que elige en un entorno administrativo, es incapaz de establecer generalizaciones de interacción social-solidaria: reflejados en la teoría de juegos y el teorema de imposibilidad de Arrow. Lo cual tiene explicación en el tipo de axiomas que debe cumplir un individuo racional, condición que trae consigo incompatibilidades entre estrategias competitivas y cooperativas. Que por el contrario, en un contexto culturalista si encuentra cabida la combinación de estrategias competitivas y cooperativas, llevando a acciones colectivas o de interacción social. ABSTRACT: This research concerns how the notion of rationality, the representative individual of the rational choice theory, which elects administrative environment, is incapable of social-solidarity interaction generalizations: reflected in game theory and theorem Arrow’s impossibility. Which is explained by the type of axioms of a rational individual, a condition that brings inconsistencies between competitive and cooperative strategies? Instead, a place culturalist context if the combination is competitive and cooperative strategies, leading to collective action or social interaction? PALABRAS CLAVE: administración competitiva vs. administración solidaria, culturalismo, teoría de Juegos,teorema de imposibilidad de Arrow. KEYWORDS: competitive vs. solidarity administration, culturalism, game theory, arrow’s impossibility theorem

Individuo y estrategia: un modelo geométrico-matemático de negociación

Con la presente investigación se pretende mostrar la posible relación entre la matemática y las ciencias sociales. En este caso, se expone específicamente la conexión de algunos elementos que provienen de la teoría de juegos, junto con algunas ideas extraídas de la sociología de la acción enfocadas a presentar un modelo de negociación. Esto da como resultado el distanciamiento de la noción de individuo racional, expuesto por John Nash en sus planteamientos sobre teoría de juegos, al presentar nosotros una inclinación por la idea de razonabilidad que permite contar con individuos competitivos y cooperadores a la vez. Con base en ello mostramos una alternativa guiada por el principio de creencia cognitiva.With this research is to show the possible relationship between mathematics and the social sciences. In this case, specifically the connection of some elements from game theory, along with some ideas from the sociology of action aimed to present a negotiation model is exposed. This results in detachment of the notion of rational individual exposed by John Nash in their approach to game theory, presenting us with a penchant for the idea of reasonableness that allows for competitive and cooperative individuals at once. Based on this we show guided by the principle of cognitive belief alternative

La justicia como equidad : una disputa desde la filosofía normativa

1 archivo PDF (18 páginas). fhquadragintaquattuorEste trabajo expone el modelo de justicia como equidad de Rawls en tanto campo agonístico primario, desde donde se tradicionalmente tratados por separado por las diversas disciplinas de las ciencias sociales. Palabras clave: Teoría de la justicia. Racionalidad. Justici

Towards Molecular Modification of Carbon Nanotube Junctions in Thin Film Transistors

Carbon nanotube thin film transistors have recently been used on flexible and transparent substrates for applications in integrated circuits and display drivers. Such networks are of interest due to their relatively high carrier mobility and mechanical flexibility. However, the ION/IOFF ratio of these networks varies inversely with the carrier mobility, and advances in reducing the electrical and thermal resistance of nanotube junctions are needed to improve the device performance and reliability. The objective of this work is create a process to improve CNT TFT device performance by using 0-dimensional molecules to modify the physical properties of the nanotube junctions. Our preliminary data indicate C60 fullerenes deposited on CNT TFTs results in decreased carrier mobility and a reduced ION/ IOFF ratio. This is likely a result of an n-type doping effect by the C60 molecules on the otherwise p-type CNTs, leading to increased p-n junctions throughout the CNT network. While this effect is detrimental to p-type CNT TFT device performance it highlights the potential of 0-dimensional molecules in tuning the transport properties of CNT networks for applications such as transparent electrodes, chemical sensors, and transistors

Spatial Prediction of Coastal Bathymetry Based on Multispectral Satellite Imagery and Multibeam Data

The coastal shallow water zone can be a challenging and costly environment in which to acquire bathymetry and other oceanographic data using traditional survey methods. Much of the coastal shallow water zone worldwide remains unmapped using recent techniques and is, therefore, poorly understood. Optical satellite imagery is proving to be a useful tool in predicting water depth in coastal zones, particularly in conjunction with other standard datasets, though its quality and accuracy remains largely unconstrained. A common challenge in any prediction study is to choose a small but representative group of predictors, one of which can be determined as the best. In this respect, exploratory analyses are used to guide the make-up of this group, where we choose to compare a basic non-spatial model versus four spatial alternatives, each catering for a variety of spatial effects. Using one instance of RapidEye satellite imagery, we show that all four spatial models show better adjustments than the non-spatial model in the water depth predictions, with the best predictor yielding a correlation coefficient of actual versus predicted at 0.985. All five predictors also factor in the influence of bottom type in explaining water depth variation. However, the prediction ranges are too large to be used in high accuracy bathymetry products such as navigation charts; nevertheless, they are considered beneficial in a variety of other applications in sensitive disciplines such as environmental monitoring, seabed mapping, or coastal zone management