315 research outputs found
Minor Street Gaps and Capacity at Unsignalized Intersections in Argentina
Capacity analysis for two way stop controlled (TWSC) intersections is mainly based on headway acceptance theory. Critical headways and follow up times are fundamental parameters in capacity estimation. Both factors clearly show the influence of driver behaviour on traffic operations. The critical headway parameter is typically associated with safety and
operational performance of this intersection type.
This paper explores critical headways and follow up times by analyzing data from video recorded tapes collected in urban intersections located in the city of Cordoba, Argentina in order to derive local values that can be used in capacity estimates at unsignalized intersections. Maximum likelihood methodology and regression analysis are employed. An
exponential model is then used to assess the relationships between headways and capacity.
Estimates for both headways are significantly smaller than the values given in version 2010 of the Highway Capacity Manual. Increased capacity, due to critical headway and follow up time reductions, becomes proportionally greater as conflicting flows grow. Percent differences increase while curves tend to get closer. From this point of view the conclusion is
that intersections operate more efficiently, but also more dangerously.Fil: Depiante, Violeta S. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Maestría en Ciencias de la Ingeniería. Mención en Transporte; Argentina.Fil: Galarraga, Jorge J. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Maestría en Ciencias de la Ingeniería. Mención en Transporte; Argentina.Ingeniería del Transport
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Tracing the Evolution of Agglomeration Economies: Spain, 1860-1991
This article attempts to quantify how the effect of agglomeration economies on population growth has evolved over time. Using district population in Spain between 1860 and 1991, recorded approximately every decade, this article examines whether initial population affects subsequent population growth. Our results show that, while the relationship between these two variables hardly existed during the second half of the 19th century, this link increased significantly between 1910 and 1970, although this trend was abruptly interrupted by the Civil War and the autarkic period that followed. The intensity of this relationship debilitated in the 1970s, a process that continued during the 1980s as rural out-migration diminished and de-industrialisation hit traditional manufacturing sectors. Our findings also stress that agglomeration economies were stronger in medium-size districts, especially from 1960 onwards, thus suggesting that congestion costs began to mitigate the benefits arising from agglomeration economies in the largest locations
An Instrumental Variable Evaluation of Antidepressant Use on Employment Among HIV-Infected Women Using Highly-Active Antiretroviral Therapy in the United States: 1996-2004
This paper examines the effect of antidepressant use on the likelihood of being employed among HIV-positive women receiving highly active antiretroviral therapy (HAART) in the United States from 1994 to 2004. We use instrumental variables to predict antidepressant use independently of outcomes; thus, addressing potential sources of bias -- more depressed women are more likely to receive antidepressant treatment, but they are also more likely to be unemployed. The results show that antidepressant use has a positive effect on the employment probability of women living with HIV. The proposed instrumental variables can be used to identify antidepressant use in the WIHS population. Among women receiving HAART, and controlling for individual and local area labor market characteristics, the use of antidepressants is associated with a higher probability of being employed.
Implementación integrada de una plataforma telemática basada en estándares para monitorización de pacientes
Proceeding of: VI Jornadas de Ingeniería Telemática (JITEL 2007), Málaga, Spain, 17-19, SeptiembreThis paper presents a proof-of-concept design of an integrated solution of a telematic platform for home telemonitoring. It is end-to-end standards-based, using ISO/IEEE11073 in the client environment and EN13606 to send the information to an Electronic Healthcare Record (EHR) server. This solution has been implemented to comply with the standards available versions and tested in a laboratory environment to demonstrate the feasibility of an end-to-end standards-based platform.Este trabajo ha recibido el apoyo de proyectos de la Comisión Interministerial de Ciencia y Tecnología (CICYT) y de los Fondos
Europeos de Desarrollo Regional (FEDER) TSI2004-04940-C02-01, del VI Programa Marco (Pulsers II IP) IST-27142, y del Ministerio de Educación y Ciencia (beca FPU AP-2004-3568).No publicad
Different Corticostriatal Integration in Spiny Projection Neurons from Direct and Indirect Pathways
The striatum is the principal input structure of the basal ganglia. Major glutamatergic afferents to the striatum come from the cerebral cortex and make monosynaptic contacts with medium spiny projection neurons (MSNs) and interneurons. Also: glutamatergic afferents to the striatum come from the thalamus. Despite differences in axonal projections, dopamine (DA) receptors expression and differences in excitability between MSNs from “direct” and “indirect” basal ganglia pathways, these neuronal classes have been thought as electrophysiologically very similar. Based on work with bacterial artificial chromosome (BAC) transgenic mice, here it is shown that corticostriatal responses in D1- and D2-receptor expressing MSNs (D1- and D2-MSNs) are radically different so as to establish an electrophysiological footprint that readily differentiates between them. Experiments in BAC mice allowed us to predict, with high probability (P > 0.9), in rats or non-BAC mice, whether a recorded neuron, from rat or mouse, was going to be substance P or enkephalin (ENK) immunoreactive. Responses are more prolonged and evoke more action potentials in D1-MSNs, while they are briefer and exhibit intrinsic autoregenerative responses in D2-MSNs. A main cause for these differences was the interaction of intrinsic properties with the inhibitory contribution in each response. Inhibition always depressed corticostriatal depolarization in D2-MSNs, while it helped in sustaining prolonged depolarizations in D1-MSNs, in spite of depressing early discharge. Corticostriatal responses changed dramatically after striatal DA depletion in 6-hydroxy-dopamine (6-OHDA) lesioned animals: a response reduction was seen in substance P (SP)+ MSNs whereas an enhanced response was seen in ENK+ MSNs. The end result was that differences in the responses were greatly diminished after DA depletion
Dopaminergic Modulation of Corticostriatal Responses in Medium Spiny Projection Neurons from Direct and Indirect Pathways
Suprathreshold corticostriatal responses recorded from medium spiny neurons (MSNs) from the direct and indirect pathways of the basal ganglia are different. Their differences readily distinguish D1- and D2-type receptor expressing MSNs in both bacterial artificial chromosome-transgenic mice and their control littermates as well as in rats: indirect pathway neurons are more excitable than direct pathway neurons revealing autoregenerative spikes underlying their spike trains, whereas direct pathway neurons exhibit more prolonged plateau potentials and spike trains. SFK 81297, a selective agonist for D1-class receptors enhanced corticostriatal responses in direct pathway neurons, while quinelorane, a selective agonist for D2-class receptors reduced orthodromic and autoregenerative responses in indirect pathway neurons thus making both neuron classes similarly excitable. Because dopaminergic postsynaptic actions target CaV1 (L) class voltage-gated calcium channels in MSNs, we hypothesized that these channels are involved and can explain a part of the dopaminergic actions on corticostriatal integration. Both 2.5 μM nicardipine and 400 nM calciseptine, selective CaV1 channel blockers, reduced corticostriatal responses in both D1- and D2-receptor expressing neurons, respectively. A previous blockade of CaV1 channels occluded the actions of dopamine agonists in both neuronal classes. In contrast, a CaV1 (L) channel activator, 2.5 μM Bay K 8644, enhanced corticostriatal responses in neurons from both pathways. It is concluded that CaV1 intrinsic currents mediate a part of the dopaminergic modulation during orthodromic synaptic integration of cortical inputs in both classes of MSNs
Desarrollo y validación de una versión preliminar de la escala de competencia emocional en el deporte (ECE_D)
El importante papel que juegan las emociones en los contextos deportivos ha sido ampliamente defendido en la literatura
sobre psicología del deporte. El objetivo de este estudio es desarrollar y validar un instrumento para evaluar la
competencia emocional de los deportistas. La muestra la componen 367 deportistas de ambos géneros pertenecientes a
diferentes disciplinas deportivas. Se analizaron los antecedentes y las características psicométricas de la Escala de
Desarrollo Emocional (Schutte, Malouff, Hall, Haggerty, Cooper, Golden y Dornhein, 1998). Los resultados obtenidos
confirmaron en términos generales el modelo de cuatro factores propuesto por los autores originales y además, plantea la
posibilidad de incluir mejoras sustanciales del cuestionario para futuras versiones relacionadas con su aplicabilidad.The relevant role of emotions in competitive contexts has been widely supported in the sport psychology literature. The
aim of this study was to create a valid measure of emotional development in sports. The sample is composed by 367
sportsmen/women belonging to different sporting disciplines. Analyses were performed about the antecedents and the
psychometric properties of the Emotional Development Scale (Schutte, Malouff, Hall, Haggerty, Cooper, Golden &
Dornhein, 1998). Results showed that, in general terms, the initially proposed four factor model was supported.
Implications for considering the improvement of the applicability questionnaire are advance
Point of care medical device communication standars (ISO11073/IEEE1073) in patient telemonitoring
Proceeding of: European Medical and Biological Engineering and IFMBE Conference (EMBEC 2005). November 20-25, 2005. Prague, Czech Republic.This paper reviews the use of ISO11073/ IEEE1073 international standard in patient telemonitoring. The purpose of this family of standards is to allow interoperability between medical instrumentation devices and medical information systems. Its application in the field of telemonitoring can encourage telemedicine services and e-care, preventing failures and problems that are making difficult its spread (use problems, high costs of reconfigurations and actualizations). An application guide for the system engineer that want to apply them is proposed, showing the steps to follow, the benefits and handicaps in the standard implementation for different telemonitoring scenarios. The study also includes the conformity levels that have to be fulfilled, the main application points of the standard.This work was supported by projects G03/117 from Fondo de Investigaciones Sanitarias (Spanish Government) and 41/2003 from Departamento de Salud (Navarra Regional Government), and a personal grant to Miguel Galarraga from Departamento de Salud (Navarra Regional Government).No publicad
Caso en el microcentro de la Ciudad de Córdoba
Para avanzar en la movilidad sustentable en ambientes urbanos adquiere gran relevancia la creación de infraestructuras que favorezcan e incentiven el tránsito no motorizado.En muchos casos, el desarrollo de este tipo de obras puede perjudicar la circulación del tránsito motorizado. El presente documento analiza este tipo de impacto, para el caso de una intervención en el centro de la ciudad de Córdoba. Se reportan las tareas desarrolladas empleando el modelo de simulación microscópica NETSIM, con el objetivo de evaluar las condiciones de operación del tránsito vehicular en la situación sin y con proyecto, detallando las conclusiones y recomendaciones pertinentesFil: Rigazio, Rinaldo. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto Superior de Ingeniería del Transporte; Argentina.Fil: Galarraga, Jorge J. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto Superior de ingeniería del Transporte; Argentina.Fil: Herz, Marcelo. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto Superior de Ingeniería del Transporte; Argentina.Ingeniería del Transport
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