169,887 research outputs found
Calibration of soil constitutive laws by inverse analysis
No full textWhen a model is calibrated by iteratively changing the estimates of the model input parameters until the value of an objective function, which quantifies the match between observed and computed results, is minimized we are dealing with inverse analysis. The major advantage of an inverse modelling is the automatic and objective calculation of the parameter values that produce the best fit between measured data (often called observations) and computed results. The main difficulties are related to the complexity of most numerical models, which sometimes cause problems of non-uniqueness and instability of the solution or insensitivity of the results to changes in the values of the parameters. This chapter presents the main aspects related to inverse analysis techniques used to calibrate the parameters of soil constitutive laws. It comprises three main sections respectively dealing with: a computer code designed to allow inverse modeling posed as a parameter estimation problem; the use of inverse analysis to calibrate soil models from results of laboratory experiments; an inverse analysis procedure to update the design predictions of a supported excavation system using monitoring data collected during construction
Role of the orexin system in the bidirectional relation between sleep and epilepsy: New chances for patients with epilepsy by the antagonism to orexin receptors?
No full textEpilepsy is a common neurological disorder, affecting patients of all ages, reducing the quality of life, and associated with several comorbidities. Sleep impairment is a frequent condition in patients with epilepsy (PWE), and the relation between sleep and epilepsy has been considered bidirectional, as one can significantly influence the other, and vice versa. The orexin system was described more than 20 years ago and is implicated in several neurobiological functions other than in controlling the sleep–wake cycle. Considering the relation between epilepsy and sleep, and the significant contribution of the orexin system in regulating the sleep–wake cycle, it is conceivable that the orexin system may be affected in PWE. Preclinical studies investigated the impact of the orexin system on epileptogenesis and the effect of orexin antagonism on seizures in animal models. Conversely, clinical studies are few and propose heterogeneous results also considering the different methodological approaches to orexin levels quantification (cerebrospinal-fluid or blood samples). Because orexin system activity can be modulated by sleep, and considering the sleep impairment documented in PWE, the recently approved dual orexin receptor antagonists (DORAs) have been suggested for treating sleep impairment and insomnia in PWE. Accordingly, sleep improvement can be a therapeutic strategy for reducing seizures and better managing epilepsy. The present review analyzes the preclinical and clinical evidence linking the orexin system to epilepsy, and hypothesizes a model in which the antagonism to the orexin system by DORAs can improve epilepsy by both a direct and a sleep-mediated (indirect) effect
Multi-level approach for zonation of seismic slope stability: Experiences and perspectives in Italy
No full textCoupled effect of pluviometric regime and soil hydraulic properties on pore pressure distribution and on slope stability
No full textAnalisi delle pressioni interstiziali nella frana del ‘Carmine’ a Tricarico
No full textSi riportano i risultati del calcolo della distribuzione di pressioni interstiziali in un versante in frana in località Carmine a Tricarico (MT). Il modello è stato tarato con le misure eseguite in 6 piezometri Casagrande installati in 3 fori di sondaggio. Allo scopo di valutare l’influenza di anisotropia, disomogeneità e condizioni al contorno sul p.c., si è partiti da un dominio di filtrazione delimitato da verticali strumentate, ipotizzando un andamento lineare delle quote piezometriche fra i punti di misura. Si è quindi passati all’analisi di un dominio di dimensioni maggiori. I risultati mostrano che le condizioni di pressione nulla sul piano campagna e di mezzo disomogeneo ed isotropo sono quelle che meglio consentono di interpretare i dati sperimentali. La condizione idraulica imposta sul piano di campagna sembra essere giustificata anche per i periodi non piovosi
A case study in southern Italy of inverse analysis of a monitored active landslide along the banks of a reservoir
No full textOptimal use of thematic maps for landslide susceptibility assessment by means of statistical analyses: Case study of shallow landslides in fine grained soils
No full textBiological role of Toll-like receptor-4 in the brain.
No full textThe Toll-like receptors (TLRs) are a family of microbe-sensing receptors that play a central role in the regulation of the host immune system. TLR4 has been described in the brain and seems to regulate some physiological processes, such as neurogenesis. TLR4 has also been reported to play a role during neurodegenerative disorders, including Alzheimer's disease, amyotrophic lateral sclerosis, multiple sclerosis and Parkinson's disease. This review is focused on reports concerning recent insights into the role and activation mechanisms of TLR4 in the brain, in pathological and physiological conditions, as well as the therapeutic benefit that could derive from TLR4 modulation
Influenza della costante dielettrica del fluido interstiziale sulle proprietà indice delle argille
No full textCompressibility and Strength of Active Clays: Influence of Pore Fluid Dielectric Constant
No full textThis paper reports experimental results relative to the influence of pore fluid composition on liquid limit, intrinsic compressibility, permeability and residual shear strength of some smectitic soils. The soils were reconstituted with distilled water, aqueous ionic solutions at various concentrations and organic fluids with different dielectric constants. The reconstitution procedure of the materials that underwent compression tests was such as to make comparable the results relative to so different fluids. All the results were analysed with reference to the static dielectric constant D of the pore fluid. As D increases from 2 (cyclohexane) to 80 (water), liquid limit and compression index increase, whereas permeability and residual shear strength decrease. Formamide (D=110) has effects similar to those of water in the case of fluid adsorption properties, volume change behaviour and permeability, whereas it causes a noticeable increase in residual shear strength. The maximum of liquid limit and compression index, and the minimum of permeability fall in the range 80<D<110 (mixture water-formamide)
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