Focusing on Soil Foundation Heterogeneity through High-resolution Tomography

An historical building affected by differential settlements, which were triggered by an earthquake, is investigated by means of high-resolution tomography, both electrical and seismic. The objective is to image the geometric structure of the shallow soil below the building and to characterize its stiffness at low strain. A preliminary reconstruction of the geological units has been recovered through the combined use of electrical and seismic data, where the depth of the travertine bedrock varies significantly within the study site. The range of variation of the main geophysical parameters (resistivity, P- and S-wave velocities) inferred from these models has been set as reference point for tuning the results obtained from the geophysical survey performed near the building. The inverted tomographic models obtained from data acquired alongside the building exhibit heterogeneity of the shallow subsoil, which is partly founded on a weathered layer and partly on a more rigid lithotype, probably a fractured travertine or a gravel layer. Therefore the fill anthropic soils can play a relevant role for the structural stability in case of shallow foundations built on a heterogeneous subsoil

Time-lapse monitoring of an electrokinetic soil remediation process through frequency-domain electrical measurements

The electrokinetic (EK) method is an emerging technique for soil remediation, even though a monitoring system of the contaminant removal through geophysical methods has not been developed yet. In this paper, frequency-domain time-lapse measurements are used on heavy-metal contaminated sediments for monitoring an EK remediation process in a small-scale measuring cell. Our goal is to monitor the development of the electrokinetic process within the sediment and to evaluate the total time needed for the treatment. In fact, frequency-domain electrical monitoring provides complex resistivity spectra at different time steps that can be correlated to changes in the physical properties of the sediments. We perform laboratory spectral induced polarization (SIP) measurements on different samples before, during and after the EK treatment, using different electrolyte solutions (acids and tap water), commonly employed in EK remediation. Direct-current measurements (resistivity and chargeability) were also acquired on one sample for testing the reliability of the system by a comparison with a widespread commercial instrumentation for field measurements. Results indicate that resistivity is a diagnostic parameter as long as it is linked to changes in water saturation, pH and ionic concentration and not to the percentage of metal extraction. The resistivity exhibited well-defined signatures as a function of time that changes depending on the conditioning agent and the grain size distribution. These peculiarities were used to understand the physical processes occurring within the cell and consequently to assess the effectiveness of the electrokinetic treatment. Conversely, the polarization effect was negligible using acids as conditioning agents at the electrolyte chambers. Therefore, the SIP method is not effective under these conditions, being the polarization effect significant only when tap water was used at both ends of the measuring cell. In this case, we were able to correlate changes in water saturation with the time-shift observed on relaxation time distributions (RTDs) after inversion of SIP data and to observe, using normalized chargeability, that polarization is stronger at high pH values. On these basis, resistivity is suitable to monitor the development of the remediation, to optimise the energy levels required for treatment and to assess the end time of the EK process (time when metal mobilization ends). In fact, the end time of treatment can be associated with the time at which resistivity becomes stable. This time is highly dependent on the particular working conditions and sediment grain size as demonstrated by our experiments

Focusing on soil-foundation heterogeneity through high-resolution electrical and seismic tomography

The reconstruction of the current status of a historic building is essential for seismic safety assessment and for designing the retrofitting interventions since different safety and confidence factors have to be assumed, depending on the level of information about the subsoil structure. In this work, we present an investigation of the shallow subsurface below and around a historic building affected by differential settlements in order to define its geometry and to characterise its stiffness at low strain. To this end, we employed high-resolution electrical resistivity and seismic (both P-wave and S-wave) tomographies. A three-dimensional electrical resistivity tomography survey was performed to obtain more information about the type and the maximum depth of the building foundation. Electrical resistivity and seismic tomographies were carried out alongside the building, aimed at imaging the top soils and the near-surface geometry. The corresponding inverted models pointed out a remarkable heterogeneity of the shallow subsoil below the building, which is partly founded on a weathered layer and partly on a more rigid lithotype. This heterogeneity is probably a concurrent cause of the building's instability under both static and seismic loading. Our results demonstrate that the man-made fillings and the top soils have to be thoroughly investigated to fully understand the soil-structure behaviour. In this light, the integration of non-invasive high-resolution geophysical techniques, especially tomographic methods, has been proved to properly address the problem of imaging the shallow subsoil

Pavement testing by integrated geophysical methods: Feasibility, resolution and diagnostic potential

This work is focused on the assessment of the diagnostic potential of several geophysical methods when applied to the investigation of a rigid airport pavement. The potential and limit of each technique are evaluated as well as the added value deriving from their integration. Firstly, we reconstruct a high-resolution image of the pavement by a large electromagnetic and georadar screening. An advanced processing of georadar data, implemented through the picking of the arrival times of reflections for each profile, provides a quantitative estimation of the deviation between the design and the as-built thickness of layers. Additionally, electrical tomography has been applied to unequivocally identify the anomalous zones, where higher values of resistivity would be associated to porous zones that are prone to degradation and failure. The seismic tomographic survey had the additional purpose to recover the mechanical properties of the pavement in terms of both P- and S-waves and consequently of elastic constants (Poisson's ratio), whose values were consistent with those recovered in literature. The anomalies detected by each technique are consistent in their indications and they can be correlated to failure phenomena occurring at layer interfaces within the pavement structure or to unexpected variations of the layer thicknesses. The cost-effective geophysical campaign has validated the four-layered system deduced from the original design and has been used to reconstruct a high-resolution map of the pavement in order to discriminate fractures, crack-prone areas or areas where the as-built differs from the original design

Resistivity and full‐decay IP inversion for imaging a coastal aquifer prone to saline intrusion. The Pontina Plain case study (Central Italy)

Many coastal areas are affected by groundwater salinization due to the unsustainable use of groundwater resources. For a cost-effective quantitative assessment of groundwater resources, electrical resistivity (ER) tomography is often used as a standalone geophysical technique. In this paper, we present an application of the integration of direct-current ER and full-decay-induced polarization (IP) method at the Pontina Plain (Central Italy). The case study is a coastal area in Central Italy prone to salinization due to both geological and anthropogenic factors. To achieve these goals, we inverted full-decay time-domain electrical data for Cole–Cole parameters. The resulting multi-parameter model provides a first approximation prediction of the permeability, employing well-established empirical relationships with the electrical parameters. We demonstrated that our approach: (i) can locate highly conductive zones directly related to saline intrusion inland using the resistivity as a fast proxy; (ii) can remove the ambiguity in the detection of clay/silt layers in the near-surface; and (iii) permit a prediction of the permeability, employing full-decay inversion of time-domain electrical data. However, the extremely conductive environment prevents the use of IP data for the reconstruction of deep layers or detection of the salt wedge front. Therefore, this approach can be used for hydro-geophysical screening and monitoring of salinization-prone sites, where strong limitations to direct inspection exist due to external constraints (e.g., protected lands)

HEMOVIGILÂNCIA DAS REAÇÕES TRANSFUSIONAIS IMEDIATAS: OCORRÊNCIAS, DEMANDA E CAPACIDADE DE ATENDIMENTO

Objetivo: identificar e discutir a ocorrência de reações transfusionais (RT) imediatas, a sua relação com o tipo de hemocomponente transfundido e a demanda e capacidade de atendimento a partir de uma unidade de Hemoterapia (UH). Métodos: estudo de caso, retrospectivo, quantitativo, realizado a partir do levantamento de registros e documentos. Análise descritiva das frequências e percentuais das ocorrências e tipologias das RT, bem como, da demanda e capacidade de atendimento desta UH. Resultados: frequência de 6,43% de RTs imediatas/1.000 hemocomponentes transfundidos. A Reação Febril Não Hemolítica (RFNH) e a Reação Alérgica (RA) foram as que mais ocorreram. Maior número de RTs foram do grau I (97,5%), sendo que os concentrados de hemácias (44,1%) e de plaquetas (41,9%) foram os hemocomponentes envolvidos na maioria das RT. Conclusão: o ato transfusional não é isento de riscos e a notificação das RT tem se tornado um instrumento primordial para contínuo aperfeiçoamento da qualidade

La poesía de Alejandra Pizarnik como una búsqueda interminable

En el presente trabajo, abordaremos una selección de poemas escritos por Alejandra Pizarnik, a través de conceptos tales como deconstrucción, pliegue, significado-significante y differance, desarrollados por Jaques Derrida a lo largo de sus diversas obras. El análisis propuesto, parte de la hipótesis que postula al lenguaje poético como barrera, como una contención para no caer, en esa búsqueda reveladora de una realidad que resulta inabarcable, llevada a cabo por la poeta en sus obras. En consecuencia, entendemos como al percibir Pizarnik límites, insuficiencias en el lenguaje mismo -en todas sus manifestaciones- para expresar lo existente en su totalidad, encuentra que las palabras dejan sombras, lugares oscuros, indecibles. Finalmente, es este impedimento el que tradujo en silencio al no poder desplazar su angustia, estado que desencadenará en su emblemático suicidio. En conformidad con lo señalado, observaremos como la noción de angustia atraviesa todo los poemas aquí interpretados y resulta esencial para entender los mismos.Mesa E.Facultad de Bellas Arte

Cambios en la expresión de subunidades del RNMDA como marcadores de un aprendizaje

Fil: Cercato, Magalí Cecilia. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Buenos Aires, ArgentinaLos receptores de glutamato NMDA (RNMDA) están involucrados en aprendizaje y formación de una nueva memoria. Son fundamentales en la codificación y ?almacenamiento? de información y necesarios en la evocación. Juegan un rol crítico en el establecimiento y mantenimiento de plasticidad sináptica y en la formación y estabilización de las sinapsis durante el desarrollo. Los RNMDA son heterotetrámeros compuestos por dos subunidades GluN1, obligatorias para el ensamblado, y dos subunidades regulatorias: GluN2 (A, B. C o D) o GluN3 (A o B). GluN2A y GluN2B son las subunidades regulatorias más abundantes en telencéfalo, especialmente en regiones del SNC relacionadas con memoria y aprendizaje, como hipocampo, amígdala y corteza prefrontal (CPF).\nEn este trabajo de Tesis, nos propusimos evaluar si la adquisición de distintos tipos de aprendizaje y la inducción de plasticidad sináptica producían cambios en los niveles de las subunidades GluN1, GluN2A y GluN2B del RNMDA.\nEn la primera parte, se analizaron posibles cambios en las subunidades del RNMDA durante la consolidación y luego de la evocación de una memoria. Se entrenaron ratas Wistar en distintos paradigmas: habituación al campo abierto (CA), reconocimiento de objetos (RO) y localización espacial de objetos (LO). Luego del entrenamiento o del testeo, los animales fueron eutanasiados y se extrajeron hipocampo, CPF y amígdala para ser analizadas por western blot (WB).\nLos animales de 1, 2, 3 y 12 meses se habituaron al CA durante la sesión de 5 minutos. En los animales de 1, 2 y 3 meses pero no en los de 12 meses, los niveles de las subunidades GluN1 y GluN2A aumentaron en hipocampo, 70 minutos después de una sesión de CA capaz de generar habituación al ambiente. Este aumento es transitorio, ya que los niveles disminuyen significativamente, siendo indistintos del control a los 90 minutos. Por otro lado, 70 min luego de la evocación de una memoria reciente (1 día) o de una memoria remota (2 meses), hubo un aumento en los niveles de GluN1 y GluN2A en la CPF, involucrando a esta estructura en ?el almacenamiento? o ?persistencia de la traza? de esa memoria del ambiente. También hubo aumento de GluN1 y GluN2A en hipocampo, 70 min luego del entrenamiento en el CA con dos objetos novedosos (igual para RO y LO), lo que permite sugerir que podría tratarse de un mecanismo general relacionado con la formación de una memoria espacial. Por otra parte, 70 min después del test de LO, hubo un aumento de GluN1 y una disminución de GluN2B en hipocampo, mientras que no se detectaron cambios luego del testeo de RO, lo que podría ser explicado porque el RO es independiente del hipocampo (en esta etapa, en que se trata de la discriminación de objetos), mientras que LO sí depende de dicha estructura. Aunque los cambios detectados indican un posible aumento del RNMDA, aparece una disminución de GluN2B; podría tratarse de un mecanismo diferente relacionado con la formación de una memoria espacial sobre un ?engrama similar?.\nEn la segunda parte, evaluamos el efecto de la inducción de plasticidad sináptica en los RNMDA, utilizando un modelo in vitro. Cultivos primarios de neuronas hipocampales (14DIV) fueron estimulados mediante pulsos de KCl. Las neuronas fueron fijadas a distintos tiempos y se evaluaron las subunidades del RNMDA mediante inmunofluorescencia. Comprobamos que existen aumentos de GluN1 y Glun2A similares a los observados in vivo. Sin embargo, dada la compartimentalizacion en la expresión proteica, el análisis de este aumento debe ser considerado por separado, ya que también los mecanismos moleculares involucrados son distintos según la subunidad y el compartimiento analizado.\na. En somas, similar a lo observado in vivo, el aumento resulta significativo a los 70 min del estímulo,\nb. mientras que en dendritas, el aumento ocurre a partir de los 30? para GluN2A y de los 45 min para GluN1.\nc. En ambos compartimientos, a los 90 min los valores fueron similares a los controles, mostrando su carácter transitorio.\nd. El aumento de GluN1 en el soma, depende principalmente de: síntesis de novo de mensajeros y de traducción, mientras que a nivel de dendritas, depende de movilización desde pooles ya traducidos, retenidos en el RE a ese nivel.\ne. El aumento de GluN2A en el soma depende exclusivamente de traducción de mensajeros silenciados, mientras que en las dendritas, el aumento a los 75 min del estímulo tiene dos componentes: transporte de receptores GluN2A-RNMDA ya ensamblados y traducción de mensajeros locales silenciados.\nEstos aumentos, así como los aumentos in vivo, fueron transitorios, ya que disminuyeron a niveles no diferentes del control a los 90 min, tanto en dendritas como en los cuerpos neuronales.\nLos resultados in vivo e in vitro muestran que, luego de inducción de plasticidad o luego de un aprendizaje espacial novedoso, hay incremento de las subunidades GluN1 y GluN2A en hipocampo con curso temporal semejante, lo que permite hipotetizar que: ?habría un aumento en los RNMDA posiblemente conteniendo GluN2A, que podría actuar como una señal duradera, contribuyendo a marcar sinapsis involucradas (tagging?), dando lugar al establecimiento y mantenimiento de la plasticidad sináptica, que constituiría parte de la traza de una nueva memoria.?\nComo última parte, desarrollamos vectores derivados de virus adeno-asociados (AAV), capaces de codificar para un short-hairpin RNA (sh-RNA) anti- GluN2A (sh2A). Pudimos demostrar que la infección con el vector AAV-sh2A disminuyo la expresión de GluN2A, por lo que constituiría una herramienta útil para el estudio de los RNMDA conteniendo GluN2A, tanto in vitro como in vivo. Además, observamos que la disminución de GluN2A en las neuronas transducidas, produjo aumento del número total de espinas, principalmente de espinas inmaduras

Retablo ayacuchano: de medio de evangelización a expresión artística popular andina

El presente trabajo fue desarrollado en el marco del proyecto final de la asignatura Historia de las Artes Visuales V, siendo su principal propósito el análisis e investigación de los Retablos Ayacuchanos, desde sus orígenes coloniales hasta la actualidad. De este modo, la búsqueda se centra en los cambios estilísticos y sociales que han convertido a los retablos andinos en piezas únicas, expresión del sincretismo cultural y religioso que se produjo con la irrupción de los europeos en nuestros territorios. Hoy en día, estas obras continúan circulando y valorándose como parte del patrimonio nacional peruano, siendo un símbolo del arte popular, manteniendo vigente tradiciones, costumbres y memorias pasadas resignificadas en el tiempo, pero también, aceptando innovaciones que responden a nuevas demandas y necesidades vinculadas los mercados actuales. En tal sentido, lo interesante de estas producciones es su esencia híbrida, mutable, que logra recrear y renovar prácticas pasadas desde una experiencia presente, móvil en constante transformación.Facultad de Arte

Detecting gas upwelling hazards in coastal areas through integration of active and passive electrical and seismic methods (Fiumicino, Central Italy)

The accurate location of gas upwelling flows is still an open problem for non-invasive imaging techniques in populated areas. Gas blowouts of deep origin may represent a serious threat to human health in urban areas and should be correctly imaged with high-resolution for assessing the related hazards. In this work, we propose an integration of active (electrical resistivity tomography and high-resolution sub-bottom profiling complemented with the multibeam bathymetry) and passive (self-potential and ambient noise recordings) geophysical methods to image gas upwelling flows in the coastal area of Fiumicino (Central Italy), where the gas presence is well-documented by previous works. We demonstrate that merging seismic sub-bottom profiling and electrical resistivity tomography has enormous diagnostic potential for gas detection, since they combine the high resolution needed to correctly image the subsurface and the interfaces between different media with the high diagnostic capability of electrical methods to detect anomalies associated with the gas emissions. Passive seismic methods complement the analysis enabling an estimation of the shear-wave velocity through array measurements. Finally, the reconstruction of the natural electrical sources, inferred from the inversion of self-potential data, confirms the location of the near-surface gas upwelling flows assessed through the resistivity model. This work demonstrates that the integration of high-resolution active and passive seismic and electrical methods can be an effective choice for the accurate location of risk-prone areas by imaging the near surface gas pathways where borehole drilling is strongly limited if not forbidden