Path-integral Monte Carlo and the squeezed trapped Bose-Einstein gas

Bose-Einstein condensation has been experimentally found to take place in finite trapped systems when one of the confining frequencies is increased until the gas becomes effectively two-dimensional (2D). We confirm the plausibility of this result by performing path-integral Monte Carlo (PIMC) simulations of trapped Bose gases of increasing anisotropy and comparing them to the predictions of finite-temperature many-body theory. PIMC simulations provide an essentially exact description of these systems; they yield the density profile directly and provide two different estimates for the condensate fraction. For the ideal gas, we find that the PIMC column density of the squeezed gas corresponds quite accurately to that of the exact analytic solution and, moreover, is well mimicked by the density of a 2D gas at the same temperature; the two estimates for the condensate fraction bracket the exact result. For the interacting case, we find 2D Hartree-Fock solutions whose density profiles coincide quite well with the PIMC column densities and whose predictions for the condensate fraction are again bracketed by the PIMC estimates.Comment: 2 pages, 3 figure

Rethinking User Behaviour Comfort Patterns in the South of Spain—What Users Really Do

Although energy analysis techniques can contribute to substantial energy savings in housing stock retrofitting operations, the outcomes often deviate significantly from the predicted results, which tend to overestimate potential savings by overestimating the starting energy baselines, particularly in southern Europe. This deviation can be largely attributed to occupant practice relating to the use of air conditioning facilities and the temperatures at which occupants feel comfortable. The patterns observed differed widely from standard values. In this study environmental variables, primarily indoor air temperature both with and without HVAC, were monitored in occupied dwellings for a full year. The data gathered were supplemented with surveys on occupants’ temperature-related behaviour to define comfort patterns. The findings show that the standards in place are not consistent with actual comfort-accepted patterns in medium- to low-income housing in southern Spain, where energy consumption was observed to be lower than expected, mostly because occupants endure unsuitable, even unhealthy, conditions over long periods of time. A new user profile, better adjusted to practice in southern Europe, particularly in social housing, is proposed to reflect the current situation

Morfología de las colonias de Briozoos en relación con la hidrodinámica del medio sedimentario

La formación de arenas y calcarenitas bioclásricas de la base de la transgresión tortoniense en Alhama de Granada contiene varios tipos de formas coloniales y de acúmulos de briozoos de características peculiares, nuevas o poco conocidas. Una breve descripción de dichos tipos y el establecimiento de su relación con las distintas facies sedimentarias complementan la información sobre el medio sedimentario conseguida por los métodos sedimentológicos clásicos y permiten plantear el significado e interés de los briozoos en el análisis sedimentológico

Caracterización de sedimentos litorales en el Mioceno del distrito lignitífero del bajo Rhin, Alemania

Las Arenas de Neurath forman la cuña marina más importante entre las capas miocénicas de carbón de la Cuenca Baja del Rhin. Este estudio se basa en la definición e interpretación de facies, caracterizadas principalmente a partir de estructuras sedimentarias y sus secuencias. De él se deduce que esta unidad litoestratigráfica se depositó en ambientes que incluyen marinos, de transición y lagunares, relacionados lateralmente entre sí. A lo largo de la evolución sedimentaria la posición de la línea de costas cambió en varias ocasiones. [ABSTRACT] The so-called Neurath Sands in the main marine wedge in the miocenic coal layers of Browncoal District. According to the types and sequences of sedimentary structures several facies are defined and interpreted in this sandy body. So, we conclude they originated in coastal environments including nearshore, shore and lagoon which related each other. Shoreline moved to and from during hte sedimentary evolution

Construcción y derribo de un perfil profesional en España: el caso de Psicopedagogía y la Convergencia Europea

El EEES reestructurará el mapa de cualificaciones universitarias, abriendo el debate sobre la pertinencia de las actuales titulaciones. En este contexto, los autores consideran que la Licenciatura de Psicopedagogía es un ejemplo de la confluencia de intereses interferentes en estos debates. Con intención de aprender de esa experiencia, en este artículo, analizan cómo se ha ido reconstruyendo el perfil psicopedagógico en nuestro sistema educativo (académica, legislativa y prácticamente), mostrando, al tiempo, la disociación argumental respecto a dicha labor profesional cuando se discute sobre la pervivencia del título. Ellos defienden su congruencia y utilidad en razón de las metas y principios que orientan el proceso de Convergencia

Fluvial Architecture of the Buntsandstein-facies Redbeds in the Middle to Upper Triassic (Ladinian-Norian) of the Southeastern Edge of the Iberian Meseta (Southern Spain)

In the southeastern edge of the Iberian Meseta in southern Spain, fluvial continental Buntsandstein-facies red beds of Middle to Upper Triassic (Ladinian Norian) age unconformably overlie the folded and eroded Hercynian basement. The Setie Belts consist of an internal metamorphosed part and an external sedimentar y zone containing the Triassic deposits, with the latter seam being in turn divided into the Prebetic Zone with continental to shallow marine facies and the Subbetic Zone with pelagic facies. The Buntsandstein-facies red bed series is vertically split into three main facies associations: alluvial fans and pebbly braided rivers (conglomerates and sandstones), low-sinuosity proximal and distal sandy braided rivers (sandstones and mudstones) and coastal evaporitic sabkha (mudstones, marls and gypsum). Alluvial- fan and pebbly braided river sediments occur at the base of the sequence and cover the palaeorelief of the pre-Triassic morphology. The inner fan zone is characterized by debris-flows or mud-flows, the mid fan zone is dominated by sheet floods, and the auter fan zone is governed by stream flood and stream flow passing into pebbly braided rivers in front of the fans. With transition from restricted alluvial fans to an open braidplain, the pebbly rivers soon evolve both vertically and horizontally into sandy stream networks consisting of channels and floodplains. The channel facies comprises sheet-type and ribbon-type sandstone layers. The sheet s form complexes up to 15 m and more thiekness due to amalgamation by multilateral coalescence and multivertical stacking of individual genetical units. In the lower part of the series, the number of ehannels is rather high suggesting a non-hierarchical channel pattern where high- and low-sinuosity rivers coexisto The middle portion refleets a smaller number of very large channels thus indicating an amelioration of the hierarchical pattern. The upper part consists of variegated sabkha pIain mudstones and evaporites where channel deposits are almost absent. The floodplain facies is divided into proximal and distal parto The proximal floodplain facies comprises interbedded sandstones and mudstones containing sorne layers of nodular pedogenie carbonates and originates by overbank sheet-flood, levee overtopping and crevasse-splay sedimentation. The distal floodplain facies is built up of mud with minor layers of silt and fine sand with intercalations of micritic lacustrine limestones and originates in overbank lakes and ponds. Depositional sequen ces within the sandy braided river series comprise major sequences that are produced by migration of alluvial subenvironments during course of their aggradation, and minor sequences that are related to alternating high- and low-water stages with changing channel abandonment and stream neoformation. The fluvial architecture is highlighted by two types of depositional settings: proximal and distal facies. The proximal facies is characterized by predominantly straight channels without or with only poorly-developed levees and being infilled with sediments under rather high-energy conditions. The distal facies is characterized by low-sinuosity channels surrounded by better developed levees and being infilled under lower energy conditions than the proximal equivalents. With passage from the proximal to the distal facies, the floodplain sediments consist of increasingly more backswamp, levee and crevasse-splay deposits as well as of sediments of small meandering channels operating in the overhank plain between the large maín streams. The evaporitic complex at the top of the Triassic originates in en arid coastal intertidal belt and supratidal sahkha seam. Within the sandy braided river complexes, the different magnitudes and effectivities of currents in large channels, small watercourses and floodplain reaches are underlined by partially divergent, bimodal or even bipolar palaeocurrent directions. Copper mineralizations of mixed syngenetic and epigenetic type in the terrestrial red beds are associated with plant debris in sediments of inactive to abandoned secondary channels and comprise azurite, chrysocolla and malachite. The Triassic palaeogeographical setting represents a large bay between the European and African plates. Fluvio-lacustrine red beds of Buntsandstein facies surrounded the bay and graded laterally into coastal and shallow marine carbonates

Time relaxation of interacting single--molecule magnets

We study the relaxation of interacting single--molecule magnets (SMMs) in both spatially ordered and disordered systems. The tunneling window is assumed to be, as in Fe8, much narrower than the dipolar field spread. We show that relaxation in disordered systems differs qualitatively from relaxation in fully occupied cubic and Fe_8 lattices. We also study how line shapes that develop in ''hole--digging'' experiments evolve with time t in these fully occupied lattices. We show (1) that the dipolar field h scales as t^p in these hole line shapes and show (2) how p varies with lattice structure. Line shapes are not, in general, Lorentzian. More specifically, in the lower portion of the hole, they behave as (h/t^p)^{(1/p)-1} if h is outside the tunnel window. This is in agreement with experiment and with our own Monte Carlo results.Comment: 21 LaTeX pages, 6 eps figures. Submitted to PRB on 15 June 2005. Accepted on 13 August 200