2,734 research outputs found
The drumlin, flute and megaflute field of lago Viedma (Late Pleistocene, Santa Cruz province)
Un nuevo campo de drumlins, flutes y megaflutes ha sido identificado en el sector oriental del Lago Viedma (49º 48´ S, 77º 55´ O). En este trabajo se describen y reconocen sus elementos integrantes. Este campo de geoformas subglaciales integra las morenas de fondo de la Última Glaciación. Se ha reconocido un mÃnimo de 19 drumlins y 199 flutes y megaflutes. Se realizó un estudio morfométrico de detalle sobre una muestra escogida de 101 de estas geoformas. El estudio muestra que los megaflutes son mucho más frecuentes que los flutes y drumlins, lo cual está probablemente relacionado con la dinámica del glaciar que los ha originado y las caracterÃsticas de la carga sedimentaria basal. Se han relevado sus orientaciones acimutales por sectores y realizado perfiles longitudinales y transversales obtenidos en el terreno en dos geoformas seleccionadas. Además, se ha determinado que la orientación de los ejes mayores de estas geoformas es casi sub-paralela para cada uno de los sectores, pero varÃa sustancialmente entre el sector norte (entre N 85º E y N 37º E) y el sector sur (entre N 145º SE y N 133º SE). Esta circunstancia demuestra que las geoformas se han generado en la base del lóbulo finiglacial del Paleoglaciar Viedma, cuando éste abandonaba el valle en el cual estaba confinado y en el cual habÃa modelado la artesa que ocupa actualmente el Lago Viedma, para luego expandirse y extenderse hacia el este como un glaciar de piedemonte.A new drumlin, flute and megaflute field has been identified in the eastern shores of lago Viedma (49º 48’ S, 77º 55’ W). In this paper, their geomorphological components are identified and described. This subglacial landform field is part of the Last Glaciation ground moraines. A minimum of 19 drumlins and 199 flutes and megaflutes have been identified. A detailed morphometric study has been completed on a selected sample of 101 landforms. The study shows that megaflutes are much more frequent than flutes and drumlins, which is probably related to glacier dynamics and bed load conditions. Their azimuth orientations have been surveyed for each sector and longitudinal and transversal profiles have been measured in the field on selected landforms. In addition, it has been determined that the main axes orientation is almost sub-parallel in each of the identified sectors, but it is substantially different between the northern sector (ranging from N 85º E to N 37º E) and the southern sector (between N 145º SE and N 133º SE). This characteristic demonstrates that the landforms have been generated at the base of the Finiglacial lobe of the Viedma Paleoglacier, when this ice body abandoned the valley where it was confined and in which it had eroded the glacial valley that it is presently occupied by lago Viedma, and afterwards expanding and extending eastwards as a piedmont glacierFil: Ponce, Juan Federico. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro Austral de Investigaciones CientÃficas; ArgentinaFil: Rabassa, Jorge Oscar. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro Austral de Investigaciones CientÃficas; Argentina. Universidad Nacional de la Patagonia; ArgentinaFil: Serrat, David. Universitat de Barcelona. Deptartament de Geodinà mica i GeofÃsica; EspañaFil: MartÃnez, Oscar Alfredo. Universidad Nacional de la Patagonia; Argentin
El ejercicio de la medicina transfusional basada en evidencias
La Medicina Basada en Evidencias (MBE) es el empleo concienzudo, explÃcito y
juicioso de las mejores evidencias actuales en la toma de decisiones en relación
con el cuidado individual de los pacientes. El ejercicio de la medicina transfusional
basada en evidencias (MTBE) es imperativo para evitar el uso injustificado de la
transfusión, prevenir los riesgos que implica, impulsar la investigación clÃnica y
biocelular para identificar riesgos y beneficios para el paciente. Esta investigación
tuvo como objetivo principal determinar la importancia del ejercicio de la Medicina
Transfusional basada en Evidencias (MTBE). Además de explicar el propósito de
la MTBE, mencionar los niveles de evidencia y los procedimientos de la MBE
aplicables a la medicina transfusional. El diseño de la investigación se basó en un
estudio documental descriptivo fundamentado en la consulta de documentos con
el propósito de analizar de forma descriptiva y exploratoria el tema propuesto. El
procesamiento de la información fue acorde a los objetivos propuestos. Finalmente
se concluye que, La MBE hace que la actividad médica cotidiana se fundamente
en datos cientÃficos y no en suposiciones o creencias. La MTBE procura la
aplicación de evidencias para el diagnóstico, la condición clÃnica y su pronóstico,
que apoyen el empleo del recurso terapéutico en beneficio del paciente. La MTBE
trata de buscar las mejores evidencias posibles para evitar el uso injustificado de
la transfusión, el alto costo que esta incluye, los posibles riesgos de la transfusión
buscando alternativas idóneas, justificar el motivo de la transfusión con los
riesgos-beneficios y buscar nuevas tendencias de la transfusión como medida
terapéutica. Los niveles de evidencias son 5 respaldados por estudios: aleatorios
controlados de casos que incluye el meta-análisis, aleatorios controlados de un
número pequeño de casos, observacionales de cohortes con datos de control
concurrentes, observacionales de cohortes con datos de control históricos y Series
de Casos. Los procedimientos de la MBE aplicables a la MT: observaciones
clÃnicas, aplicación de ciencias básicas en medicina, investigación en los
pacientes, valoración de indicadores pronósticos y eficacia de los métodos
terapéuticos de rehabilitación y de prevenció
Rural community tourism and sustainable advantages in Nicaragua
Purpose – Rural community tourism (RCT) represents an experience of community-based tourism where
local population retains control over the process and the bulk of benefits. The purpose of this paper is to focus on the study of successful RCT experiences in Nicaragua to enlarge the literature of tourismsustainability.
Design/methodology/approach – Applying the resource-based theory of the firm to tourism, the paper
defines a theoretical framework where local resources and capabilities combined through organization and
strategic actions result in competitive advantages at the community level reinforcing its sustainable
dimension. The model is tested empirically through Structural Equation Modelling-Partial Least Squares
(SEM-PLS)modelling for Nicaraguan RCT experiences.
Findings – Main findings show a good performance of empirical results, with the community dimension
representing the cornerstone of the RCT project. Results remark how the presence of community tangible and intangible resources and capabilities are combined and exploited in tourism initiatives through strategies that put the preservation of the community as the central objective. This process leads to the emergence of competitive advantages that promote the sustainability of the community lifestyle, ensuring a durable approach of the rural tourism initiatives. Other interesting findings show how this type of RCT projects also promote the integration of weak rural collectives, like women and young people, or the pivotal cooperation emerging between public and private actors.
Originality/value – The paper provides a novel framework to better understand some of the key pieces
ensuring the sustainability of tourism initiatives. This theoretical setting has been applied to the case of rural areas at developing countries but could be enlarged to other contexts at developed countries having to deal with mass tourism and important related negative impacts of these activities. In sum, the main value of thepaper is to provide a framework helping to identify the context that is needed to implement successful sustainable tourism experience
Fjords in Staaten Island: morphometric description and genesis of the only fjords found in Argentine Patagonia
La isla de los Estados se encuentra ubicada en el extremo sur de Argentina, formando parte de la provincia de Tierra del Fuego,Antártida e Islas del Atlántico Sur. Se sitúa entre los paralelos 54º38´S y 54º55´S y los meridianos 63º48´O y 64º46´O. Isla de los Estadospresenta la particularidad de ser el único lugar de Argentina cuyas costas están en su mayorÃa ocupadas por fiordos, es decir, geoformascompuestas por artesas glaciarias inundadas por el mar en ascenso luego de la glaciación. En el presente trabajo se procedió a laconfección de un detallado inventario de dichos fiordos, incluyendo su posición geográfica, dimensiones, superficie, orientación, profundidadmáxima, sustrato litológico y estructuras geológicas asociadas. El número total de fiordos relevados es de 18.Fjords in Staten Island: morphometric description and genesis of the only fjords found in Argentine Patagonia. Staaten Island (Isla de los Estados) is located at the southernmost end of Argentina, forming part of the province of Tierra del Fuego, Antarctica and South Atlantic Islands. It is found between latitude 54º38' and 54º55' S and longitude 63º48' and 64º46' W. Staaten Island is the only place of Argentina whose coastal areas are mostly occupied by fjords, i.e., landforms composed of glacial valleys flooded by the ascending sea after the glaciation. In this work, a detailed inventory of the fjords has been prepared, including their geographical location, morphometric parameters, areal surface, orientation, maximum depth, bedrock lithology and associated geological structures. The total number of surveyed fjords is 18.Fil: Ponce, Juan Federico. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro Austral de Investigaciones CientÃficas; ArgentinaFil: Rabassa, Jorge Oscar. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro Austral de Investigaciones CientÃficas; Argentina. Universidad Nacional de la Patagonia "San Juan Bosco"; ArgentinaFil: MartÃnez, Oscar Alfredo. Universidad Nacional de la Patagonia "San Juan Bosco"; Argentin
An enigmatic new archosauriform from the Carnian-Norian, Upper Triassic, Ischigualasto Formation of northwestern Argentina
In this contribution we introduce a new Late Triassic archosaur, Incertovenator longicollum gen. et sp. nov., with an unusual combination of character states that are present in certain early avemetatarsalian and pseudosuchian archosaur clades. The holotype consists of a partial postcranial skeleton, preserving most of the axial skeleton and displaying a marked anteroposterior elongation in the cervical vertebrae. We include I. longicollum gen. et sp. nov. into one of the most comprehensive early archosaur phylogenetic data sets available, and recover it as either an early diverging avemetatarsalian, closely associated with the clade Aphanosauria and Ornithodira, or as an early diverging loricatan closely related to Mandasuchus tanyauchen in the most parsimonious trees. We further evaluate which alternative phylogenetic positions can I. longicollum gen. et sp. nov. take in the suboptimal trees, and determined which character states support those alternative positions in comparison with those of the unconstrained analysis. The analyses recover the new taxon in three main general phylogenetic placements within Archosauria, as well as one position outside this clade, highlighting widespread morphological evolutionary convergence towards neck elongation in several clades of Triassic archosauriforms.Fil: Yáñez, Imanol. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - San Juan. Centro de Investigaciones de la Geosfera y Biosfera. Universidad Nacional de San Juan. Facultad de Ciencias Exactas FÃsicas y Naturales. Centro de Investigaciones de la Geosfera y Biosfera; ArgentinaFil: Pol, Diego. Consejo Nacional de Investigaciones CientÃficas y Técnicas; Argentina. Museo Paleontológico Egidio Feruglio; ArgentinaFil: Leardi, Juan MartÃn. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Alcober, Oscar A.. Universidad Nacional de San Juan; ArgentinaFil: MartÃnez, Ricardo Néstor. Universidad Nacional de San Juan; Argentin
MHCP: Multimedia Hybrid Cloud Computing Protocol and Architecture for Mobile Devices
[EN] Multimedia cloud computing has appeared as a very attractive environment for the business world in terms of providing cost-effective services with a minimum of entry costs and infrastructure requirements. There are some architecture proposals in the related literature, but there is no multimedia cloud computing architecture with hybrid features specifically designed for mobile devices. In this article, we propose a new multimedia hybrid cloud computing architecture and protocol. It merges existing private and public clouds and combines IaaS, SaaS and SECaaS cloud computing models in order to find a common platform to deliver real time traffic from heterogeneous multimedia and social networks for mobile users. The developed protocol provides suitable levels of QoS, while providing a secure and trusted cloud environment.Jimenez, JM.; DÃaz Santos, JR.; Lloret, J.; Romero MartÃnez, JO. (2019). MHCP: Multimedia Hybrid Cloud Computing Protocol and Architecture for Mobile Devices. IEEE Network. 33(1):106-112. https://doi.org/10.1109/MNET.2018.1300246S10611233
Cutting frequency and height on the quality of Megathyrsus maximus (cv. Gattonpanic)
El estudio que se presenta a continuación tuvo como objetivo evaluar la frecuencia e intensidad de la calidad nutricional en la materia seca (MS) del pasto Megathyrsus maximus (cv. Gatton panic), y fue desarrollado en la Cabaña Doña Anita, provincia del Chaco, Argentina. Se empleó un diseño completamente al azar con un arreglo factorial de 2 alturas de corte (A = 0,15 y 0,30 m), 3 frecuencias (F = 30, 45 y 90 dÃas) y 2 tiempos (T = 90 y 180 dÃas) con cinco repeticiones para cada uno (60 unidades experimentales). Se determinó el porcentaje de MS, proteÃna bruta (PB), fibra detergente ácido (FDA), fibra detergente neutra (FDN) y digestibilidad (DI). En el caso de la PB, se encontró una interacción entre las variables A x T y F x T. Para la interacción T x A, los cortes realizados en menor tiempo presentaron diferencia significativa (p :<: :0,05) en las dos alturas. Para la interacción T x F en la combinación 90 x 30, hay diferencia significativa (p <: 0,05) respecto a las restantes combinaciones. Respecto a la FDN, para la variable altura, el contenido de esta se incrementa al aumentar aquella (p <: 0,05) debido a un mayor alargamiento de tallos y hojas. En cuanto a la FDA se observaron diferencias (p <: 0,05) entre los valores para la interacción T x A para 180 dÃas con 0,15 y 0,30 m. Para la digestibilidad, se encontraron las diferencias significativas (p <: 0,05) en la interacción de T x A. Se concluye que el mayor contenido de proteÃna bruta se obtuvo con la frecuencia de 30 dÃas. La FDN y la FDA aumentaron con el mayor tiempo y la altura de la pastura
Energy Savings Consumption on Public Wireless Networks by SDN Management
[EN] In order to use the energy more efficiently, network algorithms and protocols must incorporate in their decision mechanisms some functions focused on saving energy. In this paper we have studied different features and parameters of wireless networks to establish their relationship with the power consumption. First, we have analyzed the variation of power consumption of access points (APs) in function of the antenna transmission power. Second, we have collected user information from real public wireless network to determine the real requirements of network resources in real time basis. Based on this information, a new extension for Openflow protocol over Software-Defined Networking (SDN) networks will be proposed to manage the wireless network, with the aim to keep the optimal network performance with minimal power consumption. This extension introduces new Openflow messages and a new function to be incorporated in SDN controllers and Openflow enabled devices. The proposal will be validated by appropriated simulations based on real scenarios: a shopping center and a municipal wireless network.This work has been supported by the Ministerio de EconomÃa y Competitividad , through the Convocatoria 2014. Proyectos I + D - Programa Estatal de Investigación CientÃfica y Técnica de Excelencia in the Subprograma Estatal de Generación de Conocimiento , Project TIN2014-57991-C3-1-P and the Programa para la Formación de Personal Investigador (FPI-2015-S2-884) by the Universitat Politècnica de València .Jimenez, JM.; Romero MartÃnez, JO.; Lloret, J.; DÃaz Santos, JR. (2019). Energy Savings Consumption on Public Wireless Networks by SDN Management. Mobile Networks and Applications. 24(2):667-677. https://doi.org/10.1007/s11036-016-0784-7S667677242Khoa Nguyen K, Jaumard B (2009) Routing engine architecture for next generation routers: evolutional trends. 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In international conference on advanced technologies for communications, ATC 2012, IEEE, Hanoi, Vietnam, 10–12 Oct 2012, pp 309–313. doi: 10.1109/ATC.2012.6404282Kaup F, Melnikowitsch S, Hausheer D (2014) Measuring and modeling the power consumption of OpenFlow switches. In IEEE international conference on network and service management (CNSM), Rio de Janeiro, Brazil, 17–21 Nov 2014, pp 181–186DATA SHEET. ARUBA 103 SERIES ACCESS POINTS (2016). Available at: http://www.arubanetworks.com/assets/ds/DS_AP103Series.pdf . Accessed 3 Nov 2016DATA SHEET. ARUBA RAP-100 SERIES REMOTE ACCESS POINTS (2016). Available at: http://www.arubanetworks.com/assets/ds/DS_RAP-100.pdf . Accessed 3 Nov 2016Cisco Aironet 1240AG Series 802.11A/B/G Access Point Data Sheet (2016). Available at: http://www.cisco.com/c/en/us/products/collateral/collaboration-endpoints/unified-ip-phone-7900-series/product_data_sheet0900aecd8031c844.html . 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Especies atlánticas en un contexto mediterráneo: el caso de la provincia de Cuenca
Se analiza la ecologÃa, corologÃa y grado de protección de la flora considerada atlántica de la provincia de Cuenca (España)
Controlador robusto LMI para un helicóptero de dos grados de libertad
This article presents the design of a robust H∞ controller using techniques of linear matrix inequalities (LMIs) for controlling the position of Pitch and Yaw in a helicopter. Designing a FF + LMI controller is presented for stabilizing the system, and further the design of LMI + FF + integrator controller is performed to make the tracking error equal to zero. Thereafter the results of simulations are showed on the nonlinear system model and a comparison with FF+LQR and FF+LQR+I which were developed by device manufacturers.Este artÃculo presenta el diseño de un controlador robusto H∞ usando técnicas de desigualdades matriciales lineales (LMI), para controlar la posición de Pitch y de Yaw en un helicóptero. Se presenta el diseño de un controlador FF+LMI con el propósito de conseguir la estabilización del sistema, y adicionalmente se realiza el diseño de un controlador FF+LMI+Integrador, para hacer que el error de seguimiento sea igual a cero. Posteriormente se presentan los resultados de las simulaciones sobre el modelo no lineal del sistema, asà como una comparación con los controladores FF+LQR y FF+LQR+I desarrollados por los fabricantes del dispositivo
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