Search results for "equation"

Social Determinants of Success: Social Media, Corporate Governance and Revenue

2019

This study examined how social media (Twitter and LinkedIn) relates to the operating revenue by investigating the effect of the use of social media by the board of directors. To tackle this question, we analyzed the mediating and moderating relationship of social media on the effect of board size in operating revenue (turnover). We studied the implications of the use of social media by the board members by using structural equation modeling (SEM). The data consisted of a random sample of 100 companies listed on the NASDAQ. The study makes two main contributions. First, it shows interesting differences in the use of social media for the operating revenue. Our results suggest that while Twitt…

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…

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…

Sediment delivery processes and chemical transport in a small forested basin

2005

Recent reaserch has directed attention to the properties of the eroded material because of its influence in deposition phenomena and in carrying capacity of pollutant materials

Testing the Universal Soil Loss Equation-MB equation in plots in Central and South Italy

2019

Planning soil conservation strategies requires predictive techniques at event scale because a large percentage of soil loss over a long-time period is due to relatively few large storms. Considering runoff is expected to improve soil loss predictions and allows relation of the process-oriented approach with the empirical one, furthermore, the effects of detachment and transport on soil erosion processes can be distinguished by a runoff component. In this paper, the empirical model USLE-MB (USLE-M based), including a rainfall-runoff erosivity factor in which the event rainfall erosivity index EI30 of the Universal Soil Loss Equation (USLE) multiplies the runoff coefficient QR raised to an ex…

Applying the RUSLE and ISUM in the Tierra de Barros Vineyards (Extremadura, Spain) to Estimate Soil Mobilisation Rates

2020

Spain is one of the largest wine producers in the world, with Extremadura (south-west Spain) being its second-largest producing region after Castilla La Mancha. Within Extremadura, the most traditional and productive viticulture region is the Tierra de Barros, which boasts an annual production of 3&times

Numerical simulation of fluid-structure interaction between acoustic and elastic waves

2011

Convergence rate of the Euler scheme for diffusion processes

2006

Sensitivity Analysis in Nonrandomized Longitudinal Mediation Analysis

2021

Mediation analysis relies on an untestable assumption of the no omitted confounders, which posits that an omitted variable that confounds the relationships between the antecedent, mediator, and outcome variables cannot exist. One common model in alcohol addiction studies is a nonrandomized latent growth curve mediation model (LGCMM), where the antecedent variable is not randomized, the two covarying mediators are latent intercept and slope modeling longitudinal effect of the repeated measures mediator, and an outcome variable that measures alcohol use. An important gap in the literature is lack of sensitivity analysis techniques to assess the effect of the violation of the no omitted confou…