Italo Calvino, scrittore ecologista

Il saggio indaga l'interesse dell'opera di Calvino per la tematica ecologica, con particolare attenzione al racconto La nuvola di smog e alle Città invisibili

Gold nanowires-based sensor for quantification of H2O2 released by human airway epithelial cells

Hydrogen peroxide (H2O2) is a biomarker relevant for oxidative stress monitoring. Most chronic airway diseases are characterized by increased oxidative stress. To date, the main methods for the detection of this analyte are expensive and time-consuming laboratory techniques such as fluorometric and colorimetric assays. There is a growing interest in the development of electrochemical sensors for H2O2 detection due to their low cost, ease of use, sensitivity and rapid response. In this work, an electrochemical sensor based on gold nanowire arrays has been developed. Thanks to the catalytic activity of gold against hydrogen peroxide reduction and the high surface area of nanowires, this sensor allows the quantification of this analyte in a fast, efficient and selective way. The sensor was obtained by template electrodeposition and consists of gold nanowires about 5 high and with an average diameter of about 200 nm. The sensor has excellent properties in terms of reproducibility, repeatability and selectivity. The sensor was validated by quantifying the hydrogen peroxide released by human airways A549 cells exposed or not to the pro-oxidant compound rotenone. The obtained results were validated by comparing them with those obtained by flow cytometry after staining the cells with the fluorescent superoxide-sensitive Mitosox Red probe giving a very good concordance

Soil erosion in Sicily: testing hydro-morphological approaches

I processi di denudazione sulla Terra sono fenomeni naturali di modellazione della sua superficie sotto l'azione di una serie di agenti, tra i quali il deflusso delle acque superficiali svolge un ruolo centrale soprattutto nelle zone climatiche umide. Ogni processo di modellazione è caratterizzato da tre fasi: erosione, trasporto e deposito. Nel caso di fenomeni legati al deflusso dell'acqua, devono essere analizzati in un sistema molto complesso, l’acqua infatti scorre con modalità diverse dai versanti (overland flow) ai ruscelli (rete di drenaggio) ai fiumi (canali). Allo stesso tempo, la litosfera espone al lavoro meccanico dell'acqua diversi tipi di geo-materiali, che vanno da rocce cementate molto resistenti a terreni e detriti molto deboli. Nel caso delle rocce s.s. le differenze in termini di erodibilità sono legate ai processi litogenetici (composizione, tessitura, struttura) e ai successivi fenomeni atmosferici che ne possono modificare lo stato originale. Gran parte della Terra è in realtà "coperta" dai prodotti degli agenti atmosferici o dai depositi dei processi di modellazione (detriti s.s., in geomorfologia). Lo strato mediamente stabile è l'orizzonte di base dove la vegetazione cresce e fissa l'eluvium (suolo s.s., in geomorfologia). I depositi detritici sono il risultato dell'azione erosiva dell'agente modellante e possono avere caratteristiche molto diverse a seconda del processo genetico specifico.Secondo gli elementi molto generali menzionati sopra, l'approccio allo studio dell'erosione mette lo scienziato di fronte a una sfida molto complessa. Tuttavia, un approccio semplificato può fornire strumenti per comprendere e modellare i processi in misura sufficiente per affrontare le esigenze attuali. Infatti, se la logica naturale dei processi di erosione è indiscutibile, gli effetti legati all'incrocio di questi processi e l'attività umana sono di interesse in quanto sono correlati ad alcuni aspetti di rischio. La perdita del suolo è ovviamente una fonte diretta di danni per l'agricoltura e le coltivazioni. Il deterioramento del suolo e dei detriti può provocare fenomeni distruttivi come debris floods e debris flow o ridurre la sezione del canale disponibile sui ponti e riempire i serbatoi artificiali riducendone la loro capacità di stoccaggio.Questa tesi cerca di indagare le problematiche dell'erosione del suolo in Sicilia, focalizzandosi su tre principali approcci.Il primo approccio si basa sull'analisi dei processi di erosione da una prospettiva sperimentale, cercando le relazioni tra la portata liquida e la portata solida, misurati in sezioni fluviali, e le caratteristiche idro-morfodinamiche dei bacini idrologici. In particolare, i dati storici della rete regionale delle stazioni di misura idrometriche sono stati analizzati costruendo le Sediment Rating Curves (SRC), che predicono la concentrazione del sedimento in sospensione (Suspended Sediment Concentration) dalla portata liquida (Q), e analizzando i cicli annuali di isteresi media. Un approccio diverso è stato adottato nel secondo caso sperimentale, in cui SWAT (Soil and Water Assessment Tool), un modello continuo fisicamente basato a scala di bacino e sviluppato dall'USDA-ARS, è stato applicato al bacino del fiume San Leonardo. L'obiettivo di SWAT è determinare in che modo l'uso e la gestione del territorio possano influire sulle portate liquide e sulle portate solide nei bacini idrici. In SWAT, l'erosione e la resa dei sedimenti sono stimati dalla Modified Universal Soil Loss Equation (MUSLE). Mentre la più conosciuta ed applicata USLE (Universal Soil Loss Equation) utilizza la pioggia come indicatore dell'energia erosiva, la MUSLE utilizza la quantità di deflusso funzione delle condizioni di umidità antecedenti e dell'energia delle precipitazioni. Nella terza ed ultima applicazione, la valutazione dell'erosione idrica è stata effettuata nell'ambito di uno studio di vulnerabilità all’erosione costiera per stimare il contributo dell’apporto di sedimento nelle unità fisiografiche costiere siciliane. In particolare, il modello spazialmente distribuito WaTEM/SEDEM è stato utilizzato per valutare il carico sedimentario trasportato nelle zone costiere. Il modello WaTEM/SEDEM è costituito da tre componenti principali: valutazione dell'erosione del suolo, calcolo della capacità di trasporto dei sedimenti e applicazione in un algoritmo di trasporto dei sedimenti. In WaTEM/SEDEM l'erosione del suolo è calcolata con una versione modificata della RUSLE. Una volta che il tasso medio annuale di erosione è noto, l’algoritmo viene utilizzato per trasferire la quantità di suolo prodotta (erosione lorda) dalla sorgente alla rete fluviale in base alla equazione della capacità di trasporto (TC in Mg yr-1).Denudation processes on Earth are intricate and natural modeling phenomena of its surface under the action of a set of agents, among which water runoff surface plays a central role in humid climatic areas. Each modeling process is marked by erosion s.s., transport, and deposit stages, which in the case of runoff water-related phenomena, have to be analyzed in a very complex system. In fact, running water flows with different modes from hillslopes (overland flow) to streams (drainage network) to rivers (channel). At the same time, the lithosphere is exposed to the mechanic work of running water with very different types of geo-materials, ranging from very (too) resistant cemented rocks to very weak soils and debris. In the case of rocks s.s., differences in terms of erodibility are linked to the lithogenetic processes (composition, texture, structure) and to subsequent weathering phenomena, which can modify the original status in the outcropping horizon volumes. A large part of the Earth is actually “covered” by the products of weathering processes or the deposits of the modeling processes (debris s.s., in geomorphology). The moderately stable weathered layer is the base horizon where vegetation grows and fixes the eluvium (soil s.s., in geomorphology). Debris deposits are the result of the erosive action of the modeling agent and can have very different characteristics according to the specific genetic process.According to the general elements above, approaching the study of erosion poses the scientist in front of a very intricate challenge. However, a simplified approach can furnish tools for understanding and modeling the processes to an extent suitable enough to face the current requirements. In fact, if the natural rationale of erosion processes is out of doubt, the effects of mixing these processes and human activity are of interest as some risk aspects are related. Soil loss is obviously a direct source of damage for agriculture and farming. Deteriorating soil and debris can result in destructive phenomena such as debris floods and debris flow, reducing the available channel section at bridges, or filling artificial reservoirs, reducing their storage capacity.This thesis tries to investigate water erosion issues in Sicily, with a specific focus on three main adopted approaches.The first approach is based on the analysis of the erosion processes from an experimental perspective, searching relations between the measured flow of water and sediment through a stream or fluvial section and the subtending hydro-morphodynamic, which merge in two time changing measured parameters all the effects of the interplay between rainfall/temperature forcing and slope, stream, and channel response.In particular, the available historical data of the hydrometric gauge stations' regional network are analyzed by modeling Sediment Rating Curves (SRCs), which predict the Suspended Soil Concentration (SSC) from the water discharge (Q) and analyzing the mean hysteresis annual loops. A different approach was adopted in the second experimental case, where SWAT (Soil and Water Assessment Tool), a physically-based continuous model for catchment scale simulations developed by the USDA-ARS, was applied to the San Leonardo River basin. SWAT's objective is to determine how land use and management can affect water, sediment, and agricultural chemical yields in ungauged watersheds. In SWAT, erosion and sediment yield are estimated from the Modified Universal Soil Equation (MUSLE). While the USLE uses rainfall as an indicator of erosive energy, MUSLE uses the amount of runoff, which should improve the sediment yield prediction because runoff is a function of antecedent moisture conditions as well as rainfall energy. Therefore, differently from USLE, delivery ratios are not needed with MUSLE because the runoff factor represents energy in detaching and transporting sediment.In a third application, water erosion assessment is carried out in the framework of a coastal erosion study to estimate the contribution of soil delivery at the coastal physiographic units in the advancement/retreatment stages. In particular, the spatially distributed model WaTEM/SEDEM is used to evaluate the sediment load carried to the coastal areas. The WaTEM/SEDEM model consists of three main components: soil erosion assessment, sediment transport capacity calculation, and sediment routing. Soil erosion is predicted with a modified version of RUSLE for 2-dimensional landscapes. Once the mean annual erosion rate is known at each grid cell, a routing algorithm is used to transfer the displaced soil amount (gross erosion) from the source to the river network according to the transport capacity (TC in Mg yr-1)

Comparing Hydrus-2D/3D and Philip (1984)’s model to assess wetting bulb expansion from buried and surface point sources

In surface and subsurface drip irrigation systems, predicting the size expansion of the wetting bulb and the irrigation time are mandatory for water saving, and help drive their design and scheduling. At this aim, different hydrological models have been suggested to predict the wetting bulb expansion from buried and surface point sources. In this work, we compare the results obtained by the application of Hydrus-2D/3D and Philip (1984) model. The Philip (1984) model accounts for the Gardner conductivity function, which is not implemented in Hydrus 2D/3D. Moreover, in the Philip (1984) model, a certain approximation in the choice of the water contents to be used for calculating the average volumetric water content behind the wetting front, θav, is necessary, also considering that definitions do not seem univocal. For example, the water content at the wetting front was assumed as the θav, value when soil hydraulic conductivity, K, was equal to 1 mm/day by Cook et al. (2003) and 1 mm/h by Thorburn et al. (2003). For the purpose of the comparison, an extended analysis aiming at detecting the parameter ranges of the van Genuchten-Mualem model (van Genuchten 1980), which provide hydraulic conductivity functions matching those of Gardner, was preliminary conducted. Then, for van Genuchten-Mualem parameters falling in such parameters’ ranges, the average volumetric water content that is required in the Philip (1984) model was calculated in Hydrus-2D/3D. For sandy-loam soil, results showed a quite good agreement between the simplified Philip (1984) model and the more accurate but numerically demanding Hydrus 2D/3D, suggesting that Philip (1984)’s model can be successfully applied to predict the wetting bulb expansion from buried and surface point sources, provided the average volumetric water content in the soil behind the wetting front and the saturated hydraulic conductivity are appropriately considered

Association between sedentary behavior and dynapenic abdominal obesity among older adults from low- and middle-income countries

Background Sedentary behavior, or time spent sitting, may increase risk for dynapenic abdominal obesity (DAO), but there are currently no studies on this topic. Aims Therefore, we investigated the association between sedentary behaviour and DAO in a nationally representative sample of older adults from six low- and middle-income countries. Methods Cross-sectional data from the Study on Global AGEing and Adult Health were analysed. Dynapenia was defined as handgrip strength < 26 kg for men and < 16 kg for women. Abdominal obesity was defined as waist circumference of > 88 cm (> 80 cm for Asian countries) for women and > 102 cm (> 90 cm) for men. DAO was defined as having both dynapenia and abdominal obesity. Self-reported sedentary behavior was categorized as >= 8 h/day (high sedentary behaviour) or < 8 h/day. Multivariable multinomial logistic regression was conducted. Results Data on 20,198 adults aged >= 60 years were analyzed [mean (SD) age 69.3 (13.1) years; 54.1% females]. In the overall sample, >= 8 h of sedentary behavior per day (vs. <8 h) was significantly associated with 1.52 (95%CI = 1.11-2.07) times higher odds for DAO (vs. no dynapenia and no abdominal obesity), and this was particularly pronounced among males (OR = 2.27; 95%CI = 1.42-3.62). Highly sedentary behavior was not significantly associated with dynapenia alone or abdominal obesity alone. Discussion High sedentary behaviour may increase risk for DAO among older adults. Conclusions Interventions to reduce sedentary behaviour may also lead to reduction of DAO and its adverse health outcomes, especially among males, pending future longitudinal research

Lo sport equestre in Sicilia e il caso di Ambelia. Una prima indagine geografica

La diffusione dello sport equestre e delle attività legate alla presenza dei maneggi e delle scuderie sul territorio rappresentano un inedito campo di interesse per gli studi geografici. In tal senso, il contributo, articolato in quatto paragrafi, si pone diversi obiettivi: operare una prima ricognizione teorico-analitica sull’equitazione in Sicilia, approntare una mappatura delle strutture presenti, ragionare sulle dinamiche territoriali che tale pratica sportiva incarna. Dal punto di vista metodologico la proposta si struttura sull’intreccio di analisi statistica e documentale e ricerca qualitativa sul terreno presso l’Istituto Incremento Ippico per la Sicilia di Ambelia, ritenuto il cardine della strategia di potenziamento del settore nella Regione.The spread of equestrian sport and activities linked to the presence of riding schools and stables in the area represent an unprecedented field of interest for geographic studies. In this sense, the contribution, divided into four paragraphs, has several objectives: to carry out a first theoretical-analytical survey on horse riding in Sicily, to prepare a mapping of the structures present, to think about the territorial dynamics that this sport embodies. From a methodological point of view, the proposal is structured on the intertwining of statistical and documentary analysis and qualitative research on the ground at the Equestrian Institute for Sicily in Ambelia, considered the cornerstone of the strategy to strengthen the sector in the Region

Scrittura e memoria: nessi neurodidattici per l’apprendimento. Un espediente narrativo nella formazione dei futuri insegnanti di sostegno

Il presente contributo si inserisce nel filone che guarda alla scrittura come mezzo per imparare e si sostanzia di due parti: la prima analizza i nessi tra la memoria e l’apprendimento – con focus specifico sulla memoria autobiografica – e tra scrittura e potenziamento della memoria a lungo termine; la seconda propone un modello di scrittura delle “storie di vita” come tappa progettuale iniziale che va oltre la raccolta di dati tecnici e riduzionisti per volgersi alla descrizione del profilo della classe, ma soprattutto alla ricchezza e alla profondità delle storie di vita. Il modello è stato messo a punto nel contesto del corso di specializzazione per le attività di sostegno presso l’Università di Palermo, per aiutare l’insegnante di sostegno a utilizzare le storie di vita del gruppo classe nel più ampio contesto della progettazione didattica sensoriale. Si ritiene che la scrittura – mediante il dispiego della narrazione autobiografica – possa facilitare e consolidare le informazioni contenute nella memoria a lungo termine in vista di una maggiore accuratezza rispetto alla costruzione di programmi educativi inclusivi.This contribution is part of the strand that looks at writing as a means of learning and consists of two parts: the first analyses the links between memory and learning – with a specific focus on autobiographical memory – and between writing and long-term memory enhancement; the second proposes a model for writing ‘life stories’ as an initial planning stage that goes beyond the collection of technical and reductionist data to turn to the description of the class profile, but above all to the richness and depth of life stories. The model was developed in the context of the specialisation course for support activities at the University of Palermo, to help the support teacher use the life stories of the class group in the broader context of sensory didactic design. It is believed that writing – through the deployment of autobiographical narration – can facilitate and consolidate the information contained in long-term memory with a view to greater accuracy with respect to the construction of inclusive educational programmes

Applying the Hardy Cross method to assess the energy-saving associated with closed circuits in drip irrigation systems compared to open circuits

The analysis of a looped water distribution system, usually employed in subsurface drip irrigation (SDI), under pressure and steady-state conditions, can be successfully performed if the topology of the network, the structure pipes, and the discharges at the nodes are known (Wang et al., 2021). Solving these complex networks usually requires an iterative approach. The Hardy Cross method (HCM), which was originally developed in 1936 (Cross, 1936) for manual calculations in civil engineering, can also be applied in lopped drip irrigation systems. This approach relies on the successive addition of flow-rate adjustments in each pipe to achieve the energy balance in each network segment, although limited by the Darcy-Weisbach resistance equation where the discharge exponent is set to 2. In this work, a reformulated HCM was applied to looped drip irrigation systems, considering both local losses due to emitters’ insertion and the Hazen-Williams resistance equation (discharge exponent = 1.852), which is better suited to describe friction losses in the commonly used polyethylene pipes. The hydraulic performance of closed circuits calculated by HCM was analysed and compared with that of open circuits designed by IRRILAB software application (Baiamonte, 2018). In particular, the final objective is to assess the energy-saving provided by the closed circuits (cc) in drip irrigation systems with respect to open circuits (oc). The energy-saving amount is expressed as the ratio (hratio < 1), between the inlet pressure head, hin, of the closed circuit and that of the open circuit. A predictive relationship of hratio was calibrated for 3000 simulations carried out for rectangular irrigation units characterized by different geometry, pipe diameters, emitters’ spacing and flow rate, providing relative errors RE < 0.25%. The results show that hratio depends on the pressure head tolerance of the manifold, δM, associated with the open circuits, which IRRILAB requires as an input parameter. This is very reasonable since, for high δM, the discharge circulating in the manifold is also high and closing the circuits provides low hratio (hin cc << hin oc). The vice versa occurs for low δM. Contrarily, the number of drip laterals, Nrows, has only a marginal effect on hratio. Of course, the energy-saving benefit should also consider the higher investment costs of cc than oc. However, this issue is beyond the scope of this study

La trasparenza nel lavoro pubblico. Gli obblighi di pubblicazione in materia di rapporto di lavoro e le tipologie contrattuali.

Il saggio esamina gli obblighi di trasparenza nelle amministrazioni pubbliche, con riferimento alla materia lavoristic

Industrial revolutions and human capital for the new normal: a cross-country analysis of the university system

PurposeThis paper aims to discuss the concepts of Industry 4.0, Industry 5.0, the New Normal and sustainable development (SD). The simultaneous existence of two Industrial Revolutions raises questions, thus, necessitating discussions and clarifications. The issue of SD has become a compulsory prerequisite for the future survival of humanity.Design/methodology/approachAn exploratory and inductive methodology was used to examine the phenomenon under analysis. Qualitative and quantitative data were gathered through a multi-step methodological process. A brief analysis using VoS viewer software enabled the authors to comprehend recent theoretical developments and analytical perspectives.FindingsThe findings underscore the relationship between the new sustainability challenges, digital transactions and organisational competitiveness. These intricate competitive challenges can be surmounted by focusing on educational offerings, particularly in universities. By forging international educational connections, the challenges posed by SD can be relatively easily overcome.Originality/valueThe authors conducted a comparative study of university students from four different countries: Georgia, Hungary, Italy and Ukraine. The authors observed differences in the average values across various countries, as well as disparities among respondents from the same country. Moreover, the results reveal a tendency among female respondents to be more inclined towards issues of green management and sustainability. SD cannot be realised without international collaboration. The authors present a schematic representation of the systemic connections among the universities of the participating countries to achieve SD