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

Estudio de Rehabilitación del Canal Denominado 1D en el Sector de Santa Teresa Alta (Progresiva 0+000 al 5 557.08), Distrito de Ignacio Escudero, Provincia de Sullana, Departamento Piura

El presente trabajo de investigación denominado “Estudio de Rehabilitación del Canal Denominado 1D en el Sector de Santa Teresa Alta (Progresiva 0+000 al 5+557.08), Distrito de Ignacio Escudero, Provincia de Sullana, Departamento Piura”, busca en breve y conciso, ser un trabajo de carácter social en beneficio de la comunidad de Ignacio Escudero, con la finalidad de poder mejorar la eficiencia del sistema de riego, reduciendo las pérdidas por filtración, percolación y escurrimiento del agua, revistiendo el canal con concreto, eliminando las fugas y desfogues con la colocación de compuertas de alta resistencia, mejorando la eficiencia de conducción y la oportunidad de riego. Es por eso que en la presente investigación nos centramos en el diseño estructural del canal denominado 1D y sus respectivas obras de arte, en base a la información brindada por la Junta de Usuarios del Sector Hidráulico Menor Chira Clase A y la información obtenida mediante los estudios realizados como: estudio hidrológico, estudio de mecánica de suelos, levantamiento topográfico y el cálculo de caudal para el diseño estructural del canal denominado 1D. Lo que traerá consigo un incremento de producción de las áreas cultivadas; consecuentemente un incremento en el ingreso económico del usuario, debido a que podrá contar con mayor volumen de agua y con la oportunidad de riego que los cultivos necesitan.The present research work called ""Rehabilitation Study of the Canal Denominated 1D in the Sector of Santa Teresa Alta (Progressive 0+000 to 5+557.08), District of Ignacio Escudero, Province of Sullana, Department Piura"", seeks briefly and concisely, to be a work of a social nature for the benefit of the community of Ignacio Escudero, with the purpose of being able to improve the efficiency of the irrigation system, reducing losses due to filtration, percolation and water runoff, lining the canal with concrete, eliminating leaks and vents with the placement of high-pressure gates resistance, improving driving efficiency and irrigation opportunity. That is why in the present investigation we focus on the structural design of the channel called 1D and its respective works of art, based on the information provided by the Board of Users of the Chira Class A Minor Hydraulic Sector and the information obtained through the studies carried out as: hydrological study, soil mechanics study, topographic survey and flow calculation for the structural design of the channel called 1D. What will bring with it an increase in production of cultivated areas; consequently an increase in the economic income of the user, because they will be able to count on a greater volume of water and with the irrigation opportunity that the crops need.Tesi

Estudio de Rehabilitación del Canal Denominado 1D en el Sector de Santa Teresa Alta (Progresiva 0+000 al 5 557.08), Distrito de Ignacio Escudero, Provincia de Sullana, Departamento Piura.

El presente trabajo de investigación denominado “Estudio de Rehabilitación del Canal Denominado 1D en el Sector de Santa Teresa Alta (Progresiva 0+000 al 5+557.08), Distrito de Ignacio Escudero, Provincia de Sullana, Departamento Piura”, busca en breve y conciso, ser un trabajo de carácter social en beneficio de la comunidad de Ignacio Escudero, con la finalidad de poder mejorar la eficiencia del sistema de riego, reduciendo las pérdidas por filtración, percolación y escurrimiento del agua, revistiendo el canal con concreto, eliminando las fugas y desfogues con la colocación de compuertas de alta resistencia, mejorando la eficiencia de conducción y la oportunidad de riego. Es por eso que en la presente investigación nos centramos en el diseño estructural del canal denominado 1D y sus respectivas obras de arte, en base a la información brindada por la Junta de Usuarios del Sector Hidráulico Menor Chira Clase A y la información obtenida mediante los estudios realizados como: estudio hidrológico, estudio de mecánica de suelos, levantamiento topográfico y el cálculo de caudal para el diseño estructural del canal denominado 1D. Lo que traerá consigo un incremento de producción de las áreas cultivadas; consecuentemente un incremento en el ingreso económico del usuario, debido a que podrá contar con mayor volumen de agua y con la oportunidad de riego que los cultivos necesitan.The present research work called ""Rehabilitation Study of the Canal Denominated 1D in the Sector of Santa Teresa Alta (Progressive 0+000 to 5+557.08), District of Ignacio Escudero, Province of Sullana, Department Piura"", seeks briefly and concisely, to be a work of a social nature for the benefit of the community of Ignacio Escudero, with the purpose of being able to improve the efficiency of the irrigation system, reducing losses due to filtration, percolation and water runoff, lining the canal with concrete, eliminating leaks and vents with the placement of high-pressure gates resistance, improving driving efficiency and irrigation opportunity. That is why in the present investigation we focus on the structural design of the channel called 1D and its respective works of art, based on the information provided by the Board of Users of the Chira Class A Minor Hydraulic Sector and the information obtained through the studies carried out as: hydrological study, soil mechanics study, topographic survey and flow calculation for the structural design of the channel called 1D. What will bring with it an increase in production of cultivated areas; consequently an increase in the economic income of the user, because they will be able to count on a greater volume of water and with the irrigation opportunity that the crops need.Tesi

Designing and assessing virtual learning objects to foster english for specific purposes in higher education

Four Virtual Learning Objects (VLO) were designed to incorporate English for Specific Purposes (ESP) learning at a public university in Colombia. Each VLO comprised a series of Virtual Learning Scenarios (VLS), including a vocabulary bank, a set of activities related to the six linguistic competencies (listening comprehension, oral interaction, oral production, reading comprehension, writing production, writing interaction), and an assessment and feedback sections. The impact of the VLO on students' perceptions of their progress was measured through entry and exit surveys composed of a 5-point Likert scale, multiple choice and open-ended questions. 139 students from Software Engineering (18), Journalism (22), Bachelor of Arts in Natural Sciences (50) and Nursing (49) enrolled in the University English Courses (UEC) and five teachers participated. The results reveal that students' perceptions of the VLS are positive, as each VLO is innovative and motivates learning strategies. Additionally, each VLO improved students listening and speaking skills. Therefore, the researchers recommend that teachers who design and implement VLOs focus on providing their students with skills and knowledge necessary to their specific study fields.&nbsp

Quality and quantity: transitions in antimicrobial gland use for parasite defense

Parasites are a major force in evolution, and understanding how host life history affects parasite pressure and investment in disease resistance is a general problem in evolutionary biology. The threat of disease may be especially strong in social animals, and ants have evolved the unique metapleural gland (MG), which in many taxa produce antimicrobial compounds that have been argued to have been a key to their ecological success. However, the importance of the MG in the disease resistance of individual ants across ant taxa has not been examined directly. We investigate experimentally the importance of the MG for disease resistance in the fungus-growing ants, a group in which there is interspecific variation in MG size and which has distinct transitions in life history. We find that more derived taxa rely more on the MG for disease resistance than more basal taxa and that there are a series of evolutionary transitions in the quality, quantity, and usage of the MG secretions, which correlate with transitions in life history. These shifts show how even small clades can exhibit substantial transitions in disease resistance investment, demonstrating that host–parasite relationships can be very dynamic and that targeted experimental, as well as large-scale, comparative studies can be valuable for identifying evolutionary transitions

The ants of North and Central America: the genus Mycocepurus (Hymenoptera: Formicidae)

ABSTRACT: We provide a review of the North American ants (north of Colombia) of the ant genus Mycocepurus, including keys to the workers and females, illustrations and distribution maps. The distribution of M. tardus is extended to Nicaragua and Costa Rica. The female of M. curvispinosus is described. RESUMEN: Se revisan las especies del género Mycocepurus de Norte América (al norte de Colombia). Se incluyen claves para la identificación de las obreras y las hembras, ilustraciones y mapas de distribución. Se amplia hacia el norte la distribución de M. tardus, incluyendo ahora Nicaragua y Costa Rica y se describe la hembra de M. curvispinosus

The Late Paleozoic - Early Mesozoic Chocolate Formation of southern Peru: new data and interpretations

The Chocolate Formation is exposed in southern Peru between the cities of Nazca and Tacna, mostly in the Pacifie slopes of the Cordillera Occidental and along the coast. This lithostratigraphic unit was initially described near Arequipa by Jenk s (1948; "Volcànicos Chocolate"), who assigned a Jurassic age to it. It consists of a succession of volcanic rock s, sandstones, and con glomerates. Near the top of the unit, a Sinemurian ammonite was found in a fossiliferous limestone intercalation. In Tacna a similar unit was mapped as "Junera ta Formation" by Wilson & Gard a (1962) and later equated with the Chocolate Formation (Monge & Cerv antes, 2000). Recent studies have suggested that the base of this unit might be as old as Late Carboniferous (Pino et a l., 2004; Sempere et al., 2004). Because the Chocolate volcanism is likely to have been active in the middle Permian, it partly represents a coastal equivalent of the Mitu volcanism known in the Eas tern Cordillera

Commentary on the poem “Villanelle: the psychological hour” by Ezra Pound (1915)

The commentary presents a general portrayal of the modernist poem Villanelle: The Psychological Hour, an American literary masterpiece from the early twentieth century by Ezra Pound. This paper is an attempt to conceive a didactic frame on poetry analysis to facilitate the work of the students of English literature I under my supervision. In the first hand, I present an outline of the contextual aspects of the masterpiece to continue with the interpretive analysis of the main linguistic elements that characterizes the modernist approach in American literature. Consequently, I also comment aspects related to the semantics of the text by approaching Pound’s inner cultural and emotional dimensions connoted in the poem within the frame of modernist tenets. Finally, I present a psychological portrait of the poetic voice by demonstrating that Pound’s aim is to recreate the perfect situation: his readers are able to access the semantic universe of others in a commun’entente conversation when they reach the required level to understand pragmatic, discursive, reciprocal and cultural skills of modern American discourse.Keywords: Literary analysis, teaching of literature in English, poetry, American modernism, Ezra Pound