Search results for " I+D"

L’identité symbolique. Prieto et le sujet de la sémiose

2008

L'articolo delinea la teoria della soggettivitò implicita nella semiotica di L. J. Prieto

Soggettualità: identità e disidentità

2008

Il neologismo disidentità, introdotto da G. Lai nel 1999, esprimeva la preoccupazione circa il diffondersi di “quel sentimento di disorientamento” che, di lì a poco, sarebbe divenuto il mutamento antropologico più drammatico degli ultimi anni. In questo studio si cerca di comprendere le ragioni di tale mutamento, scrutando l’avanzare dei sentimenti d’indefinitezza, vacuità, mancanza di progettualità, ecc. e rintracciandone l’origine nella carenza d’inscrizioni traspersonali, attraverso un sentiero eidetico che percorre la teoresi gruppoanalitico-soggettuale, provando anche a spingersi oltre. ---- The neologism disidentity, introduced by G. Lai in 1999, expressed the worry about the spreadin…

Elaborazione e validazione di modelli dell’impatto antropico e dei cambiamenti climatici sulle qualità dei suoli in Sicilia, con particolare attenzio…

Il declino della sostanza organica e l’erosione idrica sono due fattori di rischio di degrado del suolo fra i più diffusi in Sicilia. In che misura è possibile contrastarli modificando le attività antropiche ed in particolare quelle in ambito agricolo? Lo scopo della presente ricerca di dottorato è stato quello di mettere a punto dei modelli che permettessero di spiegare le relazioni esistenti fra le azioni dell’uomo in ambito agricolo con la sostanza organica e con l’erosione idrica nei suoli siciliani, tenendo conto anche del clima. Le due indagini sono state svolte separatamente, in parallelo, in aree agricole della Sicilia occidentale per la sostanza organica, sull’intero territorio sic…

Morphometric analysis of two calanchi areas in Sicily (Italy) by exploiting high resolution Digital Elevation Models

2013

In the Mediterranean areas, specifically in Sicily (Italy), irregular rainfalls, strong seasonal changes, scarce vegetation cover and, frequently, outcropping of clayey deposits favor water erosion phenomena. Badland landscapes are the result of severe erosion processes, characterized by steep slopes, sparse vegetation, high drainage density, rapid erosion rates and a shallow or non existing regolith profile. In this investigation we focused on the calanchi badland type, consisting of heavily dissected terrain with steep, unvegetated slopes and channels that rapidly incise and extend headwards. This research was carried out in two calanchi sites located in Sicily. The geometry of 25 badland…

Effective Practices in Mitigating Soil Erosion from Fields

2017

Soil erosion by water is a natural process that cannot be avoided. Soil erosion depends on many factors, and a distinction should be made between humanly unchangeable (e.g., rainfall) and modifiable (e.g., length of the field) soil erosion factors. Soil erosion has both on-site and off-site effects. Soil conservation tries to combine modifiable factors so as to maintain erosion in an area of interest to an acceptable level. Strategies to control soil erosion have to be adapted to the desired land use. Knowledge of soil loss tolerance, T, i.e., the maximum admissible erosion from a given field, allows technicians or farmers to establish whether soil conservation practices need to be applied …

Testing the SEDD model in Sicilian basins

2005

Abstract The Sediment Delivery Distributed (SEDD) model combines the universal soil loss equation (USLE) or the revised universal soil loss equation (RUSLE) with a sediment delivery ratio to predict basin sediment yield. The model was applied to seven Sicilian basins, ranging in size from 20 to 213 km2 . Each basin has a reservoir located at its outlet. The model was applied to each basin using a raster scheme, and a subroutine of ArcInfo software to identify the hydraulic path linking each hillslope cell to the nearest stream cell, and to calculate both the travel time and the sediment delivery ratio of each cell. A procedure for estimating the β coefficient, which appears in the expressio…

Testing a new sampler for measuring plot soil loss

2016

In order to measure soil loss in equipped plots the estimate of the weight of solid material intercepted at their lower end is required. At the experimental area of Sparacia, Sicily, the runoff produced by an erosive event is collected within storage tanks with a capacity of about 1m3. In this paper, the use of a new sampler is proposed to measure easily the weight of solid material eroded from an experimental plot and collected into a storage tank. The sampler is a cylinder having a closing valve at the bottom. Two different series of runs were carried out both to test the reliability of the sampler and to establish a sampling procedure, respectively. An analysis of various sampling config…

Supporting USLE-MM reliability by analyzing soil loss measurement errors

2017

Sampling the collected suspension in a storage tank is a common procedure to obtain soil loss data. A calibration curve of the tank has to be used to obtain actual concentration values from those measured by sampling. However, literature suggests that using a tank calibration curve was not a common procedure in the past. For the clay soil of the Sparacia (Italy) experimental station, this investigation aimed to establish a link between the relative performances of the USLE-M and USLE-MM models, usable to predict plot soil loss at the event temporal scale, and soil loss measurement errors. Using all available soil loss data, lower soil loss prediction errors were obtained with the USLE-MM (e…

USLE-based models: perspectives and limitations in soil erosion modelling

2020

Water soil erosion is a process of detachment and transport of soil particles due to rainfall and runoff and causes the landform modeling on earthʹs surface. The acceleration of soil erosion process through anthropogenic perturbation has severe impacts on soil which becomes qualitatively poor for crop establishment and growth. Planning soil conservation strategies requires prediction technologies of soil loss over a long‐time period. The Universal Soil Loss Equation (USLE), and its revised versions, are widely tested and applied in different environments throughout the world. At present, the USLE continues to be the most applied model for estimating soil loss and still represents the best c…

No-Till Soil Organic Carbon Sequestration Patterns as Affected by Climate and Soil Erosion in the Arable Land of Mediterranean Europe

2022

No-tillage (NT) has been considered an agronomic tool to sequester soil organic carbon (SOC) and match the 4p1000 initiative requirements of conservative soil management. Recently, some doubts have emerged about the NT effect on SOC sequestration, often because observations and experimental data vary widely depending on climate and geographic characteristics. Therefore, a suitable SOC accounting method is needed that considers climate and morphology interactions. In this study, the yearly ratio between SOC in NT and conventional tillage (CT) (RRNT/CT) collected in a previous study for flat (96 samples) and sloping (44 samples) paired sites was used to map the overestimation of SOC sequestra…