4,427 research outputs found

    The Ochodaeidae of Argentina (Coleoptera, Scarabaeoidea)

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    The Ochodaeidae (Coleoptera: Scarabaeoidea) of Argentina are revised. Previously, two species of Ochodaeinae were known from the country, both in the genus Parochodaeus Nikolajev: P. campsognathus (Arrow) and P. cornutus (Ohaus). An additional 7 species of Parochodaeus from Argentina are described here as new. In addition, Gauchodaeus patagonicus, new genus and new species in the subfamily Chaetocanthinae, is described. "is is the #rst record of the subfamily Chaetocanthinae in South America. Redescriptions, diagnoses, and maps are provided for each species. We also provide a key to genera and a key to species of Parochodaeus of Argentina. With this work, the number of ochodaeid species known from Argentina is increased from 2 to 10.Fil: Paulsen, M. J.. University of Nebraska; Estados UnidosFil: Ocampo, Federico Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Provincia de Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Universidad Nacional de Cuyo. Instituto Argentino de Investigaciones de las Zonas Áridas; Argentin

    Velocity fluctuations and population distribution in clusters of settling particles at low Reynolds number

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    A study on the spatial organization and velocity fluctuations of non Brownian spherical particles settling at low Reynolds number in a vertical Hele-Shaw cell is reported. The particle volume fraction ranged from 0.005 to 0.05, while the distance between cell plates ranged from 5 to 15 times the particle radius. Particle tracking revealed that particles were not uniformly distributed in space but assembled in transient settling clusters. The population distribution of these clusters followed an exponential law. The measured velocity fluctuations are in agreement with that predicted theoretically for spherical clusters, from the balance between the apparent weight and the drag force. This result suggests that particle clustering, more than a spatial distribution of particles derived from random and independent events, is at the origin of the velocity fluctuations.Comment: 13 pages, 8 figure

    Sobre la transitividad en rioplatense

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    La construcción transitiva es un fenómeno que presenta un complejo juego de significados y puede ser utilizada por el hablante según diferentes necesidades comunicativas. Es cierto que este tipo de construcción ha sido analizada desde distintas teorías y modelos lingüísticos, pero sólo un enfoque cognitivo puede ayudar a desentrañar significados producidos a distintos niveles de comunicación. El presente trabajo analiza características sintácticas, semánticas, pragmáticas y discursivas de dos construcciones transitivas ilustradas en (1), una sin duplicación del OD, la otra con duplicación: (1)14b21 T: = Y entonces cuando - m:e junté con una barrita de: - de cuarto grado - en el fondo decían, che no des la lección, no des la lección (...)Tonces me junté con ellos (...)y me decía la maestra, ¿a ver las cuentas? (...)No, no la(s) hice, decía. (risas)Tonces mandaban a llamar al padre. M: cla:ro T: este chico anda mal. (0.8) Y lo mandaron a llamar a mi viejo, una vez. Y después otra vez. La noción de transitividad ha sido considerada prototípica dentro de la lingüística cognitiva (Hopper y Thompson 1980; Taylor 1989); o sea que, según la presencia o ausencia de las propiedades que las caracterizan, existen construcciones más transitivas que otras. Mi hipótesis propone que, entre ambas construcciones, la transitividad es mayor en las que presentan duplicación del OD, y por esto aparecen destacadas o salientes dentro del contexto. El uso de estas construcciones en la variedad del Río de la Plata está motivado por dos factores: la topicalización del OD/Paciente, y/o la intencionalidad destacada del Sujeto/Agente. El análisis se basa en un corpus de veinte horas de conversaciones informales grabadas en La Plata. Se han incluido emisiones de 26 hablantes de clase media (15 mujeres y 11 varones) entre las edades de 31 y 76 años. En total fueron analizadas 424 construcciones transitivas, de las que 50 presentan duplicación del OD. En relación a otras variedades del español, los datos de La Plata muestran un uso extremadamente extendido de las construcciones con duplicación. De 50 ejemplos observados, los que incluyen OD Inanimado (26/50 ejemplos = 52 por ciento) sobrepasan a los de categoría Humano (21/50 ejemplos = 42 por ciento). (La categoría Animal no resultó significativa en la muestra.) En cuanto a la especificidad del OD, como se esperaba, cuando hay duplicación no existen ODs Inespecíficos. La mayoría de los ejemplos presenta ODs Específicos (40/50 ejemplos = 80 por ciento), y con ODs Genéricos sólo se encontraron 10/50 = 20 por cient

    Self-management of context-aware overlay ambient networks

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    Ambient Networks (ANs) are dynamically changing and heterogeneous as they consist of potentially large numbers of independent, heterogeneous mobile nodes, with spontaneous topologies that can logically interact with each other to share a common control space, known as the Ambient Control Space. ANs are also flexible i.e. they can compose and decompose dynamically and automatically, for supporting the deployment of cross-domain (new) services. Thus, the AN architecture must be sophisticatedly designed to support such high level of dynamicity, heterogeneity and flexibility. We advocate the use of service specific overlay networks in ANs, that are created on-demand according to specific service requirements, to deliver, and to automatically adapt services to the dynamically changing user and network context. This paper presents a self-management approach to create, configure, adapt, contextualise, and finally teardown service specific overlay networks

    Fast model predictive control for hydrogen outflow regulation in ethanol steam reformers

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    © 20xx IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.In the recent years, the presence of alternative power sources, such as solar panels, wind farms, hydropumps and hydrogen-based devices, has significantly increased. The reasons of this trend are clear: contributing to a reduction of gas emissions and dependency on fossil fuels. Hydrogen-based devices are of particular interest due to their significant efficiency and reliability. Reforming technologies are among the most economic and efficient ways of producing hydrogen. In this paper we consider the regulation of hydrogen outflow in an ethanol steam reformer (ESR). In particular, a fast model predictive control approach based on a finite step response model of the process is proposed. Simulations performed using a more realistic non-linear model show the effectiveness of the proposed approach in driving the ESR to different operating conditions while fulfilling input and output constraints.Peer ReviewedPostprint (author's final draft

    Predictors of improved clinical outcome following mechanical thrombectomy on South Texas patients with posterior circulation stroke

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    The South Texas population is well-acquainted with hypertension, Diabetes Mellitus Type 2 (DM2), and hyperlipidemia, all well-known risk factors for stroke1. Both anterior and posterior circulation strokes can lead to detrimental life changes, and although posterior circulation, or vertebrobasilar, strokes make up about 20% of all ischemic strokes2, their elusive characteristics often overlap with anterior circulation symptoms. In this study, we study factors that may influence the outcome of patients with posterior circulation stroke (PCS) following successful recanalization using mechanical thrombectomy. In this paper, the clinical outcome is evaluated by the primary endpoint, Modified Rankin Scale (mRS) at discharge. The outcomes (mild, moderate, severe) refer to the degree of severity of clinical impact. The current evidence that is available points towards a general poorer prognosis for recanalization of PCS than anterior circulation strokes (ACS)3. This paper seeks to investigate both patient related factors and treatment related factors that may influence the outcomes of cases PCS following mechanical thrombectomy and offers future direction that can improve our understanding of PCS
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