Riverbed sediments host important biogeochemical processes that play a key role in nutrient dynamics. Sedimentary nutrient transformations are mediated by bacteria in the form of attached biofilms. The influence of microbial metabolic activity on the hydrochemical conditions within the hyporheic zone is poorly understood. We present a hydrobiogeochemical model to assess how the growth of heterotrophic and autotrophic biomass affects the transport and transformation of dissolved nitrogen compounds in bed form‐induced hyporheic zones. Coupling between hyporheic exchange, nitrogen metabolism, and biomass growth leads to an equilibrium between permeability reduction and microbial metabolism that yields shallow hyporheic flows in a region with low permeability and high rates of microbial metabolism near the stream‐sediment interface. The results show that the bioclogging caused by microbial growth can constrain rates and patterns of hyporheic fluxes and microbial transformation rate in many streams.

No abstract

Several authors have highlighted the importance of creating a useful tool to evaluate academic Burnout through the construction and validation of specific scales to evaluate academic Burnout. Based on the literature, the aim of this study is to evaluate in Italian university the psychometric properties of the SBI-U 9 scale for Academic Burnout in university students in Italy developed by Boada-Grau and colleagues. Study 1 (N=609) examined the factor structure of the scale (Male=45.6%, Female=54.4%; Mage= 21.9; SD=2.92). Study 2 (N=412) advanced the previous SBI-U 9 validation by testing its measurement equivalence across gender (Male=48.8%, Female= 51.2%) and different type of course of study (Technical-Mathematical-Scientific=33.5%, Medical- Scientific=32.5%, Scientific-Humanistic=34%) through Multigroup Confirmatory Factor Analysis. Results confirmed a one higher-order factor structure with three first-order factors, the scale was found to be invariant across gender and different type of course of study. The findings advanced the general claim of SBI-U 9 showed an important tool for detecting the academic Burnout in university students in the Italian context, this is confirmed by the good psychometric properties of the scale.

All work sectors have been affected by the impact of the COVID-19 pandemic. The perception of risk combined with the lack of safety and fear for their own safety have caused severe psychological discomfort in workers. Of all the work sectors, the most affected was certainly the healthcare sector. In hospitals, medical staff were at the forefront of the battle against COVID-19, providing care in close physical proximity to patients and had a direct risk of being exposed to the virus. The main objective of the study was to investigate the perception of a psychosocial safety climate and the effect on engagement and psychological stress in a sample of 606 healthcare workers (physicians 39.6%, nurses 41.3%, healthcare assistant 19.1%), belonging to six organisations and organised into 11 working groups. Furthermore, we wanted to investigate the mediating effect of workaholism at both individual and group level. The results partially confirmed our hypotheses and the mediating effect at the individual level of working compulsively. A psychosocial safety climate in healthcare workers led to a decrease in engagement through the mediation of working compulsively. The mediating effect of working compulsively might be due to a climate that did not guarantee or preserve the psychological health and safety of healthcare workers. In this research, the most important limit concerns the number of organisations and the number of groups.

River bedforms arise as a result of morphological instabilities of the stream-sediment interface. Dunes and antidunes constitute the most typical patterns, and their occurrence and dynamics are relevant for a number of engineering and environmental applications. Although flow variability is a typical feature of all rivers, the bedform-triggering morphological instabilities have generally been studied under the assumption of a constant flow rate. In order to partially address this shortcoming, we here discuss the influence of (periodic) flow unsteadiness on bedform inception. To this end, our recent one-dimensional validated model coupling Dressler's equations with a refined mechanistic sediment transport formulation is adopted, and both the asymptotic and transient dynamics are investigated by modal and nonmodal analyses.

No abstract

The treatment of greywater (GW, wastewater share excluding toilet flush) through green walls can be beneficial for urban areas, favouring the diffusion of urban vegetation and reducing potable water consumption. Multiple challenges hinder the treatment performance of green walls, including the composition of the filtering material, the number of levels—i.e., rows—and the age of the system. This study investigated graphene as an additive (5%v) to a filtering medium made of coconut fibre, perlite and biochar in an open-air green wall with pots arranged into three levels. The performance of GW treatment was quantified by comparing the physicochemical features of inflow and outflow samples collected weekly over two months. Samples were also collected at each level of the green wall, and the performance of two analogous systems different by age for three months were compared. The results showed that graphene did not significantly improve treatment performance, except for the first level (e.g., 48% vs. 15% for COD, 72% vs. 51% for TSS, with and without graphene respectively). Moreover, GW treatment mostly happened along the first two levels of the green wall, with marginal depletion (e.g., 15% vs. 7% for NH4+-N) after three months of operational time.

Graywater (GW), i.e., the portion of household wastewater that excludes toilet flushes, is an interesting wastewater type because it requires only mild treatment. Green walls have been proposed as example of a nature-based solution for GW treatment due to low energy requirement and high ecological/societal benefits; however, indications about their treatment performances remain limited. This work presents experimental results of a laboratory modular green wall for GW treatment. Experiments have been performed outdoors during the winter season for three months. Each panel included four vertical columns of planted pots, and it was fed with 100 L of synthetic GW per day. Removal efficiencies were as follows (average values): 40% chemical oxygen demand, 97% biochemical oxygen demand, 61% total Kjeldhal nitrogen, 56% NO3 –-N, 57% total phosphorus, 99% Escherichia coli, and 63% anionic surfactants. This work proved the potential of an open-air green wall for treating GW, even under challenging conditions for biological treatment processes and with high hydraulic loading rates.