ASSESSING SHALLOW LANDSLIDE SUSCEPTIBILITY OF VEGETATED HILLSLOPES THROUGH A PHYSICALLY-BASED SPATIALLY-DISTRIBUTED MODEL

Slope instabilities are a serious threat to human activities, settlements, and safety worldwide. Among the different types of slope movement, shallow landslides are the most common phenomena and are often associated to other soil instabilities and to various channel processes (i.e. sediment transport, woody debris). Vegetation and in particular forests is an effective and well-known tool in preventing and mitigating hydrogeological hazards, mainly through the effects of the reinforcement exerted by the root systems. Root reinforcement, then, is a factor that should be included in hazard estimation and the resulting maps that represent a fundamental tool for planning and managing the hydrogeological hazards. Accordingly, in the last two decades, a wide number of different methods and approaches have been proposed to produce landslide hazard maps, with particular reference to Physically-Based Spatially-Distribute Models, PBSDM. However, including root reinforcement is still a challenge for the scientific community due to the huge spatial and temporal variability and the difficulties in incorporating into slope stability analysis. The main gaps to be filled can be summarized as follows: \uf0b7 the knowledge on the spatial distribution of the soil reinforcement due to the root systems have to be improved and linked to the stand forest characteristics; \uf0b7 a 3-D probabilistic PBSDM of hillslope failure able to include in a comprehensive but simple manner the presence of the forest vegetation have to be developed; \uf0b7 the use of information at coarse spatial resolution, which introduces an additional source of uncertainty has to be properly managed. This study gives a brief review of the role of forests against natural hazards and on the state of the art concerning the implementation of root reinforcement into stability models. Thereafter, it attempts to fill such gaps improving the knowledge about modelling and quantifying the effects of vegetation on slope stability. The main outcome is the development of a 3-D probabilistic PBSDM of hillslope failure, based on geotechnical sound hypothesis and stochastic approach through the Monte Carlo Simulation (MCS) analysis. Such a model is able to manage the uncertainty of model parameters and is a reliable way to deal with the problem of a lack, or a poor knowledge of terrain characteristics over large study areas. In addition, it allows evaluating the effects of silvicultural operations, to estimate the woody material, recruitable from the hillslopes in small mountainous catchments, and to quantify the additional soil reinforcement provided by some cultivations such as the grapevine. Moreover, a series of field experiments on the rooted-soil under compression is presented in order to investigate the hydro-mechanical process that occurs during the triggering mechanisms of shallow landslides. Finally, the proposed modelling framework will allow: \uf0b7 to assess the probability of hillslopes failure considering the characteristic of the vegetation and to provide more reliable shallow landslide hazard maps at catchment scale; \uf0b7 to improve the efficiency of prevention and protection due to vegetation, and particularly to the forests, against natural hazards evaluating different land management strategies; \uf0b7 to support the planning of eventual forest interventions or soil-bio engineering works identifying the areas affected by high landslide susceptibility

Quantification of in-channel large wood recruitment through a 3-D probabilistic approach

Large wood (LW) is a relevant factor in physical, chemical, environmental and biological aspects of low order mountain streams system. LW recruitment, in turn, is affected by many physical processes, such as debris flows, shallow landslides, bank erosion, snow- and wind throw, and increases the potential hazard for downstream human population and infrastructures during intense flood events. In spite of that, the LW recruitment quantification and the modelling of related processes are receiving attention only since few years ago, with particular reference to hillslope instabilities which are the dominant source of LW recruitment in mountainous terrains at regional scale. Actually, models based on the infinite slope approach, commonly adopted for slope stability analysis, can be used for estimating probable LW volume and for identifying the most hazardous areas of wood input, transport and deposition. Such models, however, generally request a robust calibration on landslide inventory and tend to overestimate unstable areas and then LW recruitment volumes. On this background, this work proposes a new LW estimation procedure which combines the forest stand characteristics of the entire catchment and a three-dimensional probabilistic slope stability model. The slope stability model overcomes the limits of the infinite slope approach and considers the spatial variability and uncertainty of the model input parameters through a Monte Carlo analysis. The forest stands characteristics allow including the root reinforcement into the stability model as stochastic input parameter, and provide the necessary information to evaluate the forest wood volume prone to be recruited as LW and its position on the hillslopes. The procedure was tested on a small mountainous headwater catchment in the Eastern Italian Alps, covered with pasture and coniferous forest and prone to shallow landslide and debris flow phenomena, especially during the late spring and the early autumn. The results showed how the proposed procedure is very promising. In fact, the estimated LW volume is comparable with the one measured by field surveys. As the procedure used data commonly available, it is of great interest as a tool for forest planning and management, and to predict the effects of forest alterations, both of natural and of anthropic origin (e.g. diseases, fire, clear-cutting or clearing), as well as helping in-channel wood retention structures positioning

A reliable rainfall–runoff model for flood forecasting: review and application to a semi-urbanized watershed at high flood risk in Italy

Many rainfall–runoff (RR) models are available in the scientific literature. Selecting the best structure and parameterization for a model is not straightforward and depends on a broad number of factors, including climatic conditions, catchment characteristics, temporal/spatial resolution and model objectives. In this study, the RR model 'Modello Idrologico Semi-Distribuito in continuo' (MISDc), mainly developed for flood simulation in Mediterranean basins, was tested on the Seveso basin, which is stressed several times a year by flooding events mainly caused by excessive urbanization. The work summarizes a compendium of the MISDc applications over a wide range of catchments in European countries and then it analyses the performances over the Seveso basin. The results show a good fit behaviour during both the calibration and the validation periods with a Nash–Sutcliffe coefficient index larger than 0.9. Moreover, the median volume and peak discharge errors calculated on several flood events were less than 25%. In conclusion, we can be assured that the reliability and computational speed could make the MISDc model suitable for flood estimation in many catchments of different geographical contexts and land use characteristics. Moreover, MISDc will also be useful for future support of real-time decision-making for flood risk management in the Seveso basin

How gender- and violence-related norms affect self-esteem among adolescent refugee girls living in Ethiopia.

BACKGROUND: Evidence suggests adolescent self-esteem is influenced by beliefs of how individuals in their reference group perceive them. However, few studies examine how gender- and violence-related social norms affect self-esteem among refugee populations. This paper explores relationships between gender inequitable and victim-blaming social norms, personal attitudes, and self-esteem among adolescent girls participating in a life skills program in three Ethiopian refugee camps. METHODS: Ordinary least squares multivariable regression analysis was used to assess the associations between attitudes and social norms, and self-esteem. Key independent variables of interest included a scale measuring personal attitudes toward gender inequitable norms, a measure of perceived injunctive norms capturing how a girl believed her family and community would react if she was raped, and a peer-group measure of collective descriptive norms surrounding gender inequity. The key outcome variable, self-esteem, was measured using the Rosenberg self-esteem scale. RESULTS: Girl's personal attitudes toward gender inequitable norms were not significantly predictive of self-esteem at endline, when adjusting for other covariates. Collective peer norms surrounding the same gender inequitable statements were significantly predictive of self-esteem at endline (ß = -0.130; p  =  0.024). Additionally, perceived injunctive norms surrounding family and community-based sanctions for victims of forced sex were associated with a decline in self-esteem at endline (ß = -0.103; p  =  0.014). Significant findings for collective descriptive norms and injunctive norms remained when controlling for all three constructs simultaneously. CONCLUSIONS: Findings suggest shifting collective norms around gender inequity, particularly at the community and peer levels, may sustainably support the safety and well-being of adolescent girls in refugee settings

The story of the “now-women”: changing gender norms in rural West Africa

This article offers a qualitative investigation of how human rights education sessions, embedded in a multi-faceted intervention, helped members of a rural community in West Africa challenge inequitable gender norms that hindered women’s political participation. Results show a change in women’s political participation and community members’ descriptions of women’s potential. Three features of the intervention contributed to this change: (1) its pedagogical approach; (2) its substantive content; and (3) the engagement of men and women together. The article calls for interventions that facilitate sustained dialogue between men and women to achieve greater gender equity

INFLUENZA DELLA NITROCARBURAZIONE IONICA SULLA MICROSTRUTTURA E LA RESISTENZA A FATICA DI ACCIAI SINTERIZZATI

La nitrocarburazione al plasma di acciai sinterizzati conferisce resistenza superficiale e limita le variazioni dimensionali. Mentre le caratteristiche microstrutturali degli strati nitrurati, in linea generale, dipendono poco dal processo di produzione dell’acciaio sinterizzato, le proprietà risultanti, che sono una sintesi delle caratteristiche del materiale base e delle modifiche introdotte dalla nitrurazione, possono esserne influenzate anche significativamente. In questo lavoro, acciai sinterizzati di interesse per il settore dei trasporti, sono stati prodotti con parametri diversi, e sottoposti allo stesso trattamento di nitrocarburazione. E’ stata condotta l’analisi microstrutturale e sono state determinate le proprietà meccaniche, con particolare riferimento alla resistenza a fatica