11,422 research outputs found

    De la Privatizacion a la Nacionalización: la Participacion en la Universidad de Tandil. Condiciones Politico- Educativas de la Coyuntura Histórica (1970 -1975)

    Get PDF
    El presente trabajo en continuidad con otros presentados por la autora en los anteriores encuentros de los Coloquios de Gestión Universitaria llevados a cabo, surge a partir de la Tesis de Maestría El proceso de Desarrollo y Diversificación de la Universidad Argentina. El caso de la UNCPBA (1964 1975) . Las anteriores presentaciones dieron cuenta de las especificidades acerca del proceso de expansión y diversificación del sistema de educación superior en Argentina, para conformar el marco en el cual se inscribe nuestro objeto de estudio la Universidad Nacional del Centro de la Provincia de Buenos Aires (UNCPBA). Por tanto en esta presentación y siempre con base en el material recabado a lo largo de la investigación, intentaremos ampliar y profundizar nuestro análisis, mostrando aquéllos factores personales, intelectuales y políticos que convergieron para que la Universidad Privada de Tandil iniciara su proceso hacia la nacionalización. Indagando cuáles fueron las condiciones político- educativas de la coyuntura histórica que a partir de 1973 marcaban el retorno del Gral. Juan Domingo Perón a la esfera gubernamental y la politización de las universidades nacionales

    Differential Calculus on Manifolds with a Boundary. Applications

    Full text link
    This paper contains a set of lecture notes on manifolds with boundary and corners, with particular attention to the space of quantum states. A geometrically inspired way of dealing with these kind of manifolds is presented,and explicit examples are given in order to clearly illustrate the main ideas.Comment: 42 pages, 6 figures, accepted for publication in International Journal of Geometric Methods in Modern Physic

    Magnetic core nanoparticles coated by titania and alumina for water and wastewater remediation from metal contaminants

    Get PDF
    Nanomaterials have been widely used for remediation of contaminated streams. However, using nanomaterials within water and wastewater might be dangerous since fate and health impact of nanoparticles is still unknown. Therefore, it is mandatory to avoid contamination by removing all the nanoparticles from the treated stream. This can be performed by immobilizing the nanoparticles on supports, although this approach leads to lower efficiency values. Another possibility is to use suspended nanoparticles: in this case, efficiency of the treatment process is enhanced. If nanomaterials have a magnetic core-shell, then suspended nanoparticles can be removed in a safe and easy was by using magnetic traps. In the present study, new nanomaterials based on magnetic core-shell structure were developed: the magnetic core guarantees a complete removal from the treated water and wastewater streams, whereas the shell (coating) is functionalized to eliminate specific classes of pollutants. A first experimental step allowed to produce the magnetic nanoparticles and perform a coating with SiO2 in order to electrically isolate the core from the ambient and to avoid degradation. This procedure is well established and the production of SiO2 coated magnetic nanoparticles are nowadays a validated procedure by using a spinning disk reactor.In a successive step, the silica shell magnetic cores were coated by titania and/or activated alumina particles with the aim of removing metals by adsorption. In the present study, the arsenic adsorption capacity of silica shell magnetic cores nanoparticles coated by titania and/or activated was investigated through kinetic experiments. All the tested adsorbents performed very well showing very rapid rates of the adsorption process. Among them, the best performing media were found to be those with titania coating. The best fitting kinetic model was found to be the pseudo-second order one for all of the adsorbents

    Location-Verification and Network Planning via Machine Learning Approaches

    Full text link
    In-region location verification (IRLV) in wireless networks is the problem of deciding if user equipment (UE) is transmitting from inside or outside a specific physical region (e.g., a safe room). The decision process exploits the features of the channel between the UE and a set of network access points (APs). We propose a solution based on machine learning (ML) implemented by a neural network (NN) trained with the channel features (in particular, noisy attenuation values) collected by the APs for various positions both inside and outside the specific region. The output is a decision on the UE position (inside or outside the region). By seeing IRLV as an hypothesis testing problem, we address the optimal positioning of the APs for minimizing either the area under the curve (AUC) of the receiver operating characteristic (ROC) or the cross entropy (CE) between the NN output and ground truth (available during the training). In order to solve the minimization problem we propose a twostage particle swarm optimization (PSO) algorithm. We show that for a long training and a NN with enough neurons the proposed solution achieves the performance of the Neyman-Pearson (N-P) lemma.Comment: Accepted for Workshop on Machine Learning for Communications, June 07 2019, Avignon, Franc

    Recurring patterns in stationary intervals of abdominal uterine electromyograms during gestation

    Get PDF
    Abdominal uterine electromyograms (uEMG) studies have focused on uterine contractions to describe the evolution of uterine activity and preterm birth (PTB) prediction. Stationary, non-contracting uEMG has not been studied. The aim of the study was to investigate the recurring patterns in stationary uEMG, their relationship with gestation age and PTB, and PTB predictivity. A public database of 300 (38 PTB) three-channel (S1-S3) uEMG recordings of 30 min, collected between 22 and 35 weeks' gestation, was used. Motion and labour contraction-free intervals in uEMG were identified as 5-min weak-sense stationarity intervals in 268 (34 PTB) recordings. Sample entropy (SampEn), percentage recurrence (PR), percentage determinism (PD), entropy (ER), and maximum length (L MAX) of recurrence were calculated and analysed according to the time to delivery and PTB. Random time series were generated by random shuffle (RS) of actual data. Recurrence was present in actual data (p<0.001) but not RS. In S3, PR (p<0.005), PD (p<0.01), ER (p<0.005), and L MAX (p<0.05) were higher, and SampEn lower (p<0.005) in PTB. Recurrence indices increased (all p<0.001) and SampEn decreased (p<0.01) with decreasing time to delivery, suggesting increasingly regular and recurring patterns with gestation progression. All indices predicted PTB with AUC≥0.62 (p<0.05). Recurring patterns in stationary non-contracting uEMG were associated with time to delivery but were relatively poor predictors of PTB

    Hepatitis C virus relies on lipoproteins for its life cycle

    Get PDF
    Hepatitis C virus (HCV) infects over 150 million people worldwide. In most cases, HCV infection becomes chronic causing liver disease ranging from fibrosis to cirrhosis and hepatocellular carcinoma. Viral persistence and pathogenesis are due to the ability of HCV to deregulate specific host processes, mainly lipid metabolism and innate immunity. In particular, HCV exploits the lipoprotein machineries for almost all steps of its life cycle. The aim of this review is to summarize current knowledge concerning the interplay between HCV and lipoprotein metabolism. We discuss the role played by members of lipoproteins in HCV entry, replication and virion production

    On the evolution of elastic properties during laboratory stick-slip experiments spanning the transition from slow slip to dynamic rupture

    Get PDF
    The physical mechanisms governing slow earthquakes remain unknown, as does the relationship between slow and regular earthquakes. To investigate the mechanism(s) of slow earthquakes and related quasi-dynamic modes of fault slip we performed laboratory experiments on simulated fault gouge in the double direct shear configuration. We reproduced the full spectrum of slip behavior, from slow to fast stick slip, by altering the elastic stiffness of the loading apparatus (k) to match the critical rheologic stiffness of fault gouge (kc). Our experiments show an evolution from stable sliding, when k>kc, to quasi-dynamic transients when k ~ kc, to dynamic instabilities when k<kc. To evaluate the microphysical processes of fault weakening we monitored variations of elastic properties. We find systematic changes in P wave velocity (Vp) for laboratory seismic cycles. During the coseismic stress drop, seismic velocity drops abruptly, consistent with observations on natural faults. In the preparatory phase preceding failure, we find that accelerated fault creep causes a Vp reduction for the complete spectrum of slip behaviors. Our results suggest that the mechanics of slow and fast ruptures share key features and that they can occur on same faults, depending on frictional properties. In agreement with seismic surveys on tectonic faults our data show that their state of stress can be monitored by Vp changes during the seismic cycle. The observed reduction in Vp during the earthquake preparatory phase suggests that if similar mechanisms are confirmed in nature high-resolution monitoring of fault zone properties may be a promising avenue for reliable detection of earthquake precursors

    ¿De la deslocalización al "backshoring"? Evidencia de los distritos industriales italianos

    Get PDF
    In recent decades, industrial districts (ID) have experienced intense delocalisation to low-cost countries, with implications for IDs’ internal structure. Recent studies, however, highlight the advantages of relocalising manufacturing in home countries. This paper investigates ID firms’ production-location strategies and backshoring decisions. The results from a survey of 259 firms in eight Italian IDs show that firms that delocalise production do not change their strategies over time and make limited recourse to backshoring. ID production is still important to guarantee product quality and access to specialised know-how.En las últimas décadas, los distritos industriales experimentaron una deslocalización intensa hacia países de bajo costo, con implicaciones en la estructura interna del distrito. Estudios recientes destacan las ventajas de volver a localizar la producción en el mercado nacional. Este artículo analiza las estrategias de localización de las empresas del distrito de producción y las decisiones de “backshoring”. El trabajo empírico consiste en un análisis descriptivo de 259 empresas ubicadas en 8 distritos industriales en Italia. Los resultados muestran que las empresas que deslocalizaron la producción no han cambiado sus estrategias con el tiempo, con un limitado recurso al “back-shoring”. No obstante, la producción del distrito es todavía importante para garantizar la calidad del producto y el acceso a un “know-how” especializado
    corecore