Effect of consolidation on the behaviour of excavations in fine-grained soils

This study deals with the detrimental effects of consolidation on the behaviour of excavations carried out in fine-grained soils. With the aim of reproducing the main aspects of the mechanical behaviour of medium-soft clays, an advanced constitutive model was adopted, which is based on bounding surface plasticity and can take into account the damage to the soil microstructure induced by plastic strains. In a first stage of the work, this constitutive model was implemented into a finite element program, and its response was studied through a series of single-element tests, evidencing the effect of the different soil parameters and initial conditions. In the present paper, the constitutive model was used to simulate the behaviour of an idealised excavation, studying the effect of the progressive dissipation of the excess pore water pressures generated during the excavation stages. It was found that, under certain conditions, the initial degree of structure can be progressively lost during consolidation. This detrimental effect produces significant deformation increments and in some cases can drive the system to collapse

Estimating effective connectivity in linear brain network models

Contemporary neuroscience has embraced network science to study the complex and self-organized structure of the human brain; one of the main outstanding issues is that of inferring from measure data, chiefly functional Magnetic Resonance Imaging (fMRI), the so-called effective connectivity in brain networks, that is the existing interactions among neuronal populations. This inverse problem is complicated by the fact that the BOLD (Blood Oxygenation Level Dependent) signal measured by fMRI represent a dynamic and nonlinear transformation (the hemodynamic response) of neuronal activity. In this paper, we consider resting state (rs) fMRI data; building upon a linear population model of the BOLD signal and a stochastic linear DCM model, the model parameters are estimated through an EM-type iterative procedure, which alternately estimates the neuronal activity by means of the Rauch-Tung-Striebel (RTS) smoother, updates the connections among neuronal states and refines the parameters of the hemodynamic model; sparsity in the interconnection structure is favoured using an iteratively reweighting scheme. Experimental results using rs-fMRI data are shown demonstrating the effectiveness of our approach and comparison with state of the art routines (SPM12 toolbox) is provided

White matter and task-switching in young adults: A Diffusion Tensor Imaging study

The capacity to flexibly switch between different task rules has been previously associated with distributed fronto-parietal networks, predominantly in the left hemisphere for phasic switching sub-processes, and in the right hemisphere for more tonic aspects of task-switching, such as rule maintenance and management. It is thus likely that the white matter (WM) connectivity between these regions is critical in sustaining the flexibility required by task-switching. This study examined the relationship between WM microstructure in young adults and task-switching performance in different paradigms: classical shape-color, spatial and grammatical tasks. The main results showed an association between WM integrity in anterior portions of the corpus callosum (genu and body) and a sustained measure of task-switching performance. In particular, a higher fractional anisotropy and a lower radial diffusivity in these WM regions were associated with smaller mixing costs both in the spatial task-switching paradigm and in the shape-color one, as confirmed by a conjunction analysis. No association was found with behavioral measures obtained in the grammatical task-switching paradigm. The switch costs, a measure of phasic switching processes, were not correlated with WM microstructure in any task. This study shows that a more efficient inter-hemispheric connectivity within the frontal lobes favors sustained task-switching processes, especially with task contexts embedding non-verbal components

X-band mini weather radar network and other wireless sensor networks for environmental monitoring

The main section of the present Ph. D. thesis is related to X-band radars. Since 2005 the Remote Sensing Group of Department of Electronics and Telecommunications of Politecnico di Torino developed an X-band mini weather radar as a standalone sensor to measure rain. Some early results have been presented until 2011 showing the proper functioning and it has been decided to realize an experimental and operative integrated network of X-band radar devoted to rain measurement. The network structure deployed during the Ph. D. period is presented, together with the analysis, the study and the realizations of some operative services, calibration procedures (including Quantitative Precipitation Estimation, QPE) and software and applications developed for the institutions which support the network realizations. The design of an innovative and low cost method to check the radar stability and proper functioning is presented: by simply acquiring a large number of ground clutter echoes during clear sky days and computing some analysis, it is shown it is possible to identify some statistical indicators that allow users and radar operators to know if the radar equipments suffered some degradations of failure. The second part of the thesis is dedicated to Wireless Sensor Networks (WSNs). After a study on WSN technologies for environmental monitoring, a first developed prototypal DGPS network is presented. Using the same multipurpose node designed for such network (or its updated releases with very small differences) and varying only their firmware, other two prototypal and fully operative WSNs are described. The designed choices are described for what concern both hardware and software

MENGA: a new comprehensive tool for the integration of neuroimaging data and the Allen human brain transcriptome atlas

Brain-wide mRNA mappings offer a great potential for neuroscience research as they can provide information about system proteomics. In a previous work we have correlated mRNA maps with the binding patterns of radioligands targeting specific molecular systems and imaged with positron emission tomography (PET) in unrelated control groups. This approach is potentially applicable to any imaging modality as long as an efficient procedure of imaging-genomic matching is provided. In the original work we considered mRNA brain maps of the whole human genome derived from the Allen human brain database (ABA) and we performed the analysis with a specific region-based segmentation with a resolution that was limited by the PET data parcellation. There we identified the need for a platform for imaging-genomic integration that should be usable with any imaging modalities and fully exploit the high resolution mapping of ABA dataset.In this work we present MENGA (Multimodal Environment for Neuroimaging and Genomic Analysis), a software platform that allows the investigation of the correlation patterns between neuroimaging data of any sort (both functional and structural) with mRNA gene expression profiles derived from the ABA database at high resolution.We applied MENGA to six different imaging datasets from three modalities (PET, single photon emission tomography and magnetic resonance imaging) targeting the dopamine and serotonin receptor systems and the myelin molecular structure. We further investigated imaging-genomic correlations in the case of mismatch between selected proteins and imaging targets

Reimagining Death in an All-Too-Human World: A Pedagogical Exploration of Pinar Yoldas' Ecosystem of Excess

This article offers a pedagogical response to Pinar Yoldas’ Ecosystem of Excess, a speculative marine ecosystem of creatures that have evolved to survive the human-induced proliferation of plastic. In questioning our relationship to death in an era of ecological devastation due to excessive consumption, it proposes a pedagogy of ambivalence to explore what Ecosystem of Excess can teach us about our complicated relations with death. The article then develops three articulations of death—death beyond finality, silent death, and relational death—that are generative for attending to the multi-faceted ways ambivalence manifests itself in the context of more-than-human death

Beyond perfection: Reclaiming death in and for education

In associating death with education, this paper explores how the death register, and in particular the denial of death, is reflected in the treatment of contemporary education, aiming to construct the future as an object of knowledge for providing certainty and authority. Through a reading of Gert Biesta’s theoretical considerations, I discuss how educational systems scientifically explained and measured are created to be fixed (or healed), in pursuit of a type of education as a social apparatus to enable or reach for a perfect future. I argue however, that such medical-like treatment runs the risk of negating the complex, relational, and fragile qualities of educational life. Into the second part, I offer new perspectives on death and loss to be imagined as occasions for emancipation within pedagogical encounters between subjects; giving space for unpredictability, riskiness, ambiguity, and messiness to occur. My overall contention is that when desires of immortality overpower an appreciation of the finitude and fragility of all things, a part of life is denied. When education is not confronted with important and challenging questions on its purposes, this should be considered dangerous or even lethal for a safe system to thrive; we miss out on what is educational in education, we miss an encounter with reality