1,791 research outputs found
Estratigrafía de Sr y evolución sedimentaria de los depósitos marinos del Mioceno temprano en el antepaís del norte de la Cuenca Austral (o Magallanes), Argentina
Early Miocene shallow marine deposits in the region of Lago Posadas-Meseta Belgrano (Argentina) represent part of the “Patagoniense” transgression, an Atlantic marine incursion that flooded large part of Patagonia, including the Austral (foreland) Basin (southern Patagonia). These deposits, referred as El Chacay (Argentina) or Guadal (Chile) formations, and the transition to the overlying Santa Cruz Formation were divided into six facies: subtidal sandbars, shallow marine sandy deposits, muddy shelf deposits, estuarine complex deposits, fluvial channels and fluvial floodplains. These are arranged in a general transgressive-regressive cycle, subdivided into two stratigraphic sequences, separated by a major erosional surface. 87Sr/86Sr ages from shell carbonate in eight oysters yielded an age range of 20.3 to 18.1 Ma for these “Patagoniense” deposits. Correlation with other dated “Patagoniense” sections in southern Patagonia, like those at Lago Argentino or Comodoro Rivadavia, indicates that they belong to a single transgression that flooded several Patagonian basins approximately at the same time. Eustasy, flexural subsidence created by tectonic loading in the adjacent fold-and-thrust belt, and basin floor paleo-topography controlled the duration of the depositional event and the sedimentation style of these shallow marine deposits.Los depósitos marino-someros del Mioceno temprano de la región del Lago Posadas-Meseta Belgano representan parte de la transgresión “Patagoniense”, una incursión marina atlántica que invadió gran parte de la Patagonia, incluyendo la Cuenca de antepaís Austral (Patagonia austral). Estos depósitos, referidos como formaciones El Chacay (Argentina) y Guadal (Chile), y su transición a la suprayacente Formación Santa Cruz, fueron divididos en seis facies: barras submareales, depósitos arenosos marino-someros, depósitos fangosos de plataforma, complejo estuarino, canales fluviales y planicie de inundación. Estas facies muestran un arreglo general transgresivo-regresivo, el que puede ser subdividido en dos secuencias estratigráficas separadas por una superficie erosiva. Resultados de ocho edades 87Sr/86Sr de carbonato tomado de valvas de ostras dieron un rango entre 20,3 Ma y 18,1 Ma para estos depósitos Patagonienses. La correlación con sucesiones equivalentes de edad conocida en la Patagonia Austral, como las del Lago Argentino o Comodoro Rivadavia, indican que estas pertenecen a una misma transgresión que inundó gran parte de la Patagonia aproximadamente al mismo tiempo. La eustacia, la subsidencia flexural creada por carga tectónica en la faja corrida y plegada adyacente, y la paleotopografía del fondo de la cuenca, controlaron la duración del evento depositacional y el estilo de sedimentación estos depósitos marino-someros.Fil: Cuitiño, José Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; ArgentinaFil: Ventura Santos, Roberto. Universidade de Brasília; BrasilFil: Alonso Muruaga, Pablo Joaquin. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires; ArgentinaFil: Scasso, Roberto Adrian. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires; Argentin
Techniques to Understand Computer Simulations: Markov Chain Analysis
The aim of this paper is to assist researchers in understanding the dynamics of simulation models that have been implemented and can be run in a computer, i.e. computer models. To do that, we start by explaining (a) that computer models are just input-output functions, (b) that every computer model can be re-implemented in many different formalisms (in particular in most programming languages), leading to alternative representations of the same input-output relation, and (c) that many computer models in the social simulation literature can be usefully represented as time-homogeneous Markov chains. Then we argue that analysing a computer model as a Markov chain can make apparent many features of the model that were not so evident before conducting such analysis. To prove this point, we present the main concepts needed to conduct a formal analysis of any time-homogeneous Markov chain, and we illustrate the usefulness of these concepts by analysing 10 well-known models in the social simulation literature as Markov chains. These models are: • Schelling\'s (1971) model of spatial segregation • Epstein and Axtell\'s (1996) Sugarscape • Miller and Page\'s (2004) standing ovation model • Arthur\'s (1989) model of competing technologies • Axelrod\'s (1986) metanorms models • Takahashi\'s (2000) model of generalized exchange • Axelrod\'s (1997) model of dissemination of culture • Kinnaird\'s (1946) truels • Axelrod and Bennett\'s (1993) model of competing bimodal coalitions • Joyce et al.\'s (2006) model of conditional association In particular, we explain how to characterise the transient and the asymptotic dynamics of these computer models and, where appropriate, how to assess the stochastic stability of their absorbing states. In all cases, the analysis conducted using the theory of Markov chains has yielded useful insights about the dynamics of the computer model under study.Computer Modelling, Simulation, Markov, Stochastic Processes, Analysis, Re-Implementation
Knowledge Transfer in Commercial Feature Extraction for the Retail Store Location Problem
Location is the most important strategic decision in retailing. The location problem is markedly
complex and multicriteria. One of the key factors to consider is the so-called balanced tenancy —i.e.,
the degree to which neighboring businesses complement each other. There are several network-based
methodologies that formalize the notion of balanced tenancy by capturing the spatial interactions between
different commercial sectors in cities. Some of these methodologies provide indices that have been successfully used as input features in location recommendation systems. However, from a predictive perspective,
it is still unknown which of the indices provides best results. In this work, we analyze the performance of six
of these indices on a set of nine Spanish cities. Our results show that the combined use of all of them in an
ensemble model such as random forest significantly improves predictive accuracy. In addition, we explore
the effect of knowledge transfer between cities from two different perspectives: 1) quantify how much the
quality of solutions degrades when the balanced tenancy of a city is explored through the indices obtained
from another city; 2) investigate the interest of network consensus approaches for knowledge transfer in
retailing.Spanish Ministry of Science, Innovation and Universities through Excellence Network under Grant RED2018-102518-T, in part by the Spanish State Research Agency under Grant PID2020-118906GB-I00/AEI/10.13039/501100011033, and in part by the Junta de Castilla y León Consejería de Educación under Grant BDNS 425389
Análisis de viabilidad de una residencia de ancianos
[Resumen]: El siguiente trabajo de fin de grado trata la elaboración y desarrollo del análisis de
viabilidad de una residencia de ancianos. En él se detalla cómo es la creación de esta
residencia, las actuaciones que se realizan para su puesta en marcha y su crecimiento
durante el horizonte temporal utilizado.
Este trabajo comienza con un plan de negocio en el que se explican las
características del proyecto, la localización de la residencia, cómo es el mercado en el
que se va actuar, la competencia, los servicios prestados a los clientes y las
instalaciones de la empresa.
A continuación se elabora un plan financiero, en el que se especifican las
estrategias y políticas necesarias para que se puedan confeccionar los estados
financieros previsionales. Por último se lleva a cabo un análisis de efectuabilidad y del
riesgo del proyecto .[Abstract]: In the present degree thesis a feasibility analysis of a retirement home is
developed. A detailed description on the creation of this residence, and the operations
made for the start-up and growth during the time horizon used are provided.
This work begins with a business plan in which characteristics of the project are
explained, such as the location of the residence, a description of the market in which
we intend to operate, the competitors, the services provided and the company facilities.
Then a financial plan is developed. In it the strategies and policies needed for the
forecasted financial statements are specified. Finally, an analysis of the feasibility and
the risk of the project is carried out.Traballo fin de grao (UDC.ECO). ADE. Curso 2015/201
Explainable machine learning for project management control
Project control is a crucial phase within project management aimed at ensuring —in an integrated manner— that the project objectives are met according to plan. Earned Value Management —along with its various refinements— is the most popular and widespread method for top-down project control. For project control under uncertainty, Monte Carlo simulation and statistical/machine learning models extend the earned value framework by allowing the analysis of deviations, expected times and costs during project progress. Recent advances in explainable machine learning, in particular attribution methods based on Shapley values, can be used to link project control to activity properties, facilitating the interpretation of interrelations between activity characteristics and control objectives. This work proposes a new methodology that adds an explainability layer based on SHAP —Shapley Additive exPlanations— to different machine learning models fitted to Monte Carlo simulations of the project network during tracking control points. Specifically, our method allows for both prospective and retrospective analyses, which have different utilities: forward analysis helps to identify key relationships between the different tasks and the desired outcomes, thus being useful to make execution/replanning decisions; and backward analysis serves to identify the causes of project status during project progress. Furthermore, this method is general, model-agnostic and provides quantifiable and easily interpretable information, hence constituting a valuable tool for project control in uncertain environments
Comparative study of classification algorithms for quality assessment of resistance spot welding joints from preand post-welding inputs
Resistance spot welding (RSW) is a widespread manufacturing process in the automotive industry. There are different approaches for assessing the quality level of RSW joints. Multi-input-single-output methods, which take as inputs either the intrinsic parameters of the welding process or ultrasonic nondestructive testing variables, are commonly used. This work demonstrates that the combined use of both types of inputs can significantly improve the already competitive approach based exclusively on ultrasonic analyses. The use of stacking of tree ensemble models as classifiers dominates the classification results in terms of accuracy, F-measure and area under the receiver operating characteristic curve metrics. Through variable importance analyses, the results show that although the welding process parameters are less relevant than the ultrasonic testing variables, some of the former provide marginal information not fully captured by the latter
Potassium channels are involved in testosterone-induced vasorelaxation of human umbilical artery
Recent studies have shown that testosterone
induces relaxation of different arteries, although the mechanism
of this action is still under debate. We investigated
the involvement of potassium channels in this mechanism.
Using standard organ bath techniques, rings of human
umbilical arteries (HUA) without endothelium were contracted
by serotonin (5-HT, 1 μM), histamine (10 μM) and
potassium chloride (KCl, 30 and 60 mM), and the
vasorelaxant effect of testosterone was analysed. Testosterone
(100 μM) relaxed human umbilical arteries contracted
with 5-HT (30.1±3.2%), histamine (55.1±2.6%), KCl
30 mM (52.9±8.3%) and KCl 60 mM (54.8±6.3%).
Flutamide (10 μM), an inhibitor of classical intracellular
testosterone receptor, and glibenclamide, an ATP-sensitive
potassium-channels (KATP) inhibitor, did not influence the
testosterone relaxant effect. 4-aminopyridine, a voltagesensitive
potassium-channels (Kv) inhibitor, decreased the
effect of testosterone on histamine- and 5-HT-contracted
arteries. Tetraethylammonium (TEA), which inhibits Kv
channels and large-conductance Ca2+-activated potassium
channels (BKCa), decreased the effect of testosterone on
KCl (60 mM)-contracted and 5-HT-contracted HUA. In
conclusion, testosterone induces relaxation of HUA, and
this effect does not appear to be mediated via a classic intracellular testosterone receptor-dependent mechanism.
Our results suggest that this relaxation is partially mediated
by activation of BKCa and KV channels. The involvement
of these two channels in testosterone-relaxant mechanism is
dependent on the pathways activated by the contractile
agent used
Evolution of equity norms in small-world networks
The topology of interactions has been proved very influential in the results of models based on
learning and evolutionary game theory. This paper is aimed at investigating the effect of structures
ranging from regular ring lattices to random networks, including small-world networks, in a
model focused on property distribution norms. The model considers a fixed and finite population
of agents who play the Nash bargaining game repeatedly. Our results show that regular networks
promote the emergence of the equity norm, while less-structured networks make possible the
appearance of fractious regimes. Additionally, our analysis reveals that the speed of adoption can
also be affected by the network structureSpanish MICINN Projects CSD2010-00034
SimulPast CONSOLIDER-INGENIO 2010 , TIN2008-06464-C03-02 and DPI2010-16920, and by the Junta de Castilla y León, References BU034A08 and GREX251-200
Experimentación, simulación y análisis de artefactos improvisados-proyectiles formados por explosión
Dentro de los artefactos explosivos improvisados se encuentran aquellos que generan proyectiles formados por explosión, penetradores de blindajes y sistemas acorazados, como los utilizados por grupos insurgentes contra las fuerzas aliadas en zona de operaciones. El objeto de este estudio es reproducir y entender el comportamiento de dichos artefactos explosivos improvisados capaces de generar proyectiles de alta velocidad y gran capacidad de penetración. La comprensión de su comportamiento permitirá mejorar el conocimiento sobre ellos, y por ende, combatirlos de forma más eficaz. Para ello se han realizado los ensayos correspondientes, obteniéndose las primeras caracterizaciones de proyectiles formados por explosión construidos de manera artesanal, tal y como haría un terrorista. Además, se han creado los modelos numéricos correspondientes a cada ensayo, que simulan todo el evento desde su inicio hasta el impacto en el objetivo, recorriendo todos los pasos intermedios. Se han ensayado 3 configuraciones y posteriormente se han simulado, usando el software de análisis por elementos finitos, LS-DYNA, con una configuración 2D axisimétrica, con mallados lagrangianos. Los resultados obtenidos por el modelo han alcanzado un alto grado de precisión con relación a los datos experimentales. A partir de aquí se puede concluir que los artefactos explosivos improvisados-proyectiles formados por explosión son una seria amenaza, y que los modelos generados permitirán conocer y ahorrar costes en la lucha contra esta amenaza, y por ende contra el terrorismo, al disponer de un enfoque holístico de la amenaza, y finalmente reducir los costes de la experimentación
- …