La Gestione dei trasporti in emergenza: attività, prodotti e risultati dell'esercitazione nazionale di Protezione Civile in Valtellina

L'articolo riporta l’esperienza maturata dal Laboratorio Mobilità e Trasporti del Politecnico di Milano in qualità di Centro di Competenza per la Gestione e la Sicurezza dei Trasporti per il Dipartimento di Protezione Civile Nazionale durante l’esercitazione nazionale di Protezione Civile in Valtellina. Le attività svolte, i prodotti realizzati e utilizzati ma soprattutto i risultati e l’esperienza emersi da una esercitazione temporalmente estesa e di estremo rilievo in ambito di Protezione Civile, si ritiene siano ancora estremamente attuali e utili come esempio per la gestione dei trasporti in caso di emergenze rilevanti

Formation and seasonal occurrence of xylem embolism in Alnus cordata.

We investigated the vulnerability of xylem to embolism and the seasonal occurrence of xylem embolism in Italian alder (Alnus cordata Loisel.) by acoustic and hydraulic methods. Wood anatomy was also studied. More than eighty percent of the vessels were less than 50 mm long and no vessels were longer than 120 mm. Mean vessel diameter was 48 μm. Ultrasound acoustic emissions from root and branch segments dehydrating in air followed a similar pattern: in both tissues, emission peaks were recorded when the relative water content of the xylem was around 0.2. In branches dehydrating in air, xylem embolism increased linearly as water potential decreased. In trees in the field, more than 80 percent of hydraulic conductivity was lost in the tree crowns during winter. Recovery from winter embolism occurred mostly before bud burst. In summer, xylem embolism was low (< 30%) and acoustic emissions from roots, stem and branches of trees in the field were also low

The PAIS? Corpus of Italian Web Texts

PAISA\u27 is a Creative Commons licensed, large web corpus of contemporary Italian. We describe the design, harvesting, and processing steps involved in its creation

Ultrasound emission after cycles of water stress in Picea abies

The relationships among rate of ultrasound acoustic emission (AE), xylem water potential and transpiration rate were investigated in 5-year-old potted saplings of Picea abies Karst. after cycles of water stress. Water-stressed plants displayed minimum xylem water potentials of –3.9 MPa, near-zero transpiration rates and up to 45 AE counts per minute. After rewatering, water-stressed plants no longer produced AEs. Well-watered control plants produced only a small number of ultrasonic AEs. After three cycles of water stress (lasting 24 days in total), it was estimated that about two-thirds of the functional tracheids were embolized. The concomitant reduction in hydraulic conductance was about 70%

TRAM-R2: A Quantitative Model for Railway Tunnel Risk Analysis

The paper introduces TRAM-R2 (Tunnel Risk Analysis Model – Road&amp;Railway), a novel quantitative risk analysis model for rail and road tunnels, compliant with European and Italian safety regulations. TRAM-R2 generates F-N curves, relating the frequency of accidental scenarios to potential fatalities, aligning with safety directives. It considers four initial events: collision, derailment, fire, and dangerous goods release, resulting in 30 scenarios analyzed using Event Tree Analysis (ETA). The model estimates fatalities considering train and tunnel characteristics and assesses user evacuation feasibility via egress modeling. It employs results of 1D, zone, and 3D computational fluid dynamics (CFD) simulations to evaluate scenario dynamics and consequences. TRAM-R2 allows simulating scenarios for different tunnels, considering layout, infrastructure, equipment, and management impacts on egress and scenario propagation. It accounts for interdependent measures and their reliability during emergencies. The paper demonstrates TRAM-R2's application through case studies, highlighting its potential for quantitative risk assessment in railway tunnels, facilitating comparison with regulatory criteria. Overall, TRAM-R2 provides a comprehensive tool for assessing and mitigating risks in rail tunnel operations, aiding compliance with safety standards and regulations

Thinning affects water-use efficiency of hardwood saplings naturally recruited in a Pinus radiata D. Don plantation.

Plantations for timber production combine the productive to the nursery function for natural regeneration of native species. Thinning plays a crucial role in recruitment and establishment of native species, by modifying the irradiance regime beneath the canopy cover. It also promotes the secondary succession towards a more stable forest, which is a main goal in protected areas. The present study was carried in a timber plantation of Pinus radiata D. Don, located in the National Park of Cilento and Vallo di Diano (Southern Italy). The ecophysiological responses of saplings of two hardwood species, Quercus cerris L. and Fraxinus ornus L., according to two contrasting (low and high) relative irradiance (RI) regimes were analysed. Leaf and tree ring δ13C values were employed as indicators of water use efficiency (WUE) to explore plant responses to light regime. A preliminary methodological comparison between bulk wood and extracted holocellulose showed no significant differences in δ13C between the two materials. Results indicate lower δ13C values, thus suggesting a lower WUE, at higher RI regimes (corresponding to heavy thinning) for both the studied species. Furthermore, Q. cerris δ13C values are lower than those of F. ornus. These results suggest that, under the same light conditions, the mesophile Q. cerris exhibits a weaker stomatal control than the xerophile F. ornus, which keeps higher WUE. In the mesic environment studied, Q. cerris may overcome F. ornus in the long run, owing to a heavy thinning

Leakage and spillover effects of forest management on carbon storage: theoretical insights from a simple model.

Leakage (spillover) refers to the unintended negative (positive) consequences of forest carbon (C) management in one area on C storage elsewhere. For example, the local C storage benefit of less intensive harvesting in one area may be offset, partly or completely, by intensified harvesting elsewhere in order to meet global timber demand. We present the results of a theoretical study aimed at identifying the key factors determining leakage and spillover, as a prerequisite for more realistic numerical studies.We use a simple model of C storage in managed forest ecosystems and their wood products to derive approximate analytical expressions for the leakage induced by decreasing the harvesting frequency of existing forest, and the spillover induced by establishing new plantations, assuming a fixed total wood production from local and remote (non-local) forests combined.We find that leakage and spillover depend crucially on the growth rates, wood product lifetimes and woody litter decomposition rates of local and remote forests. In particular, our results reveal critical thresholds for leakage and spillover, beyond which effects of forest management on remote C storage exceed local effects. Order of magnitude estimates of leakage indicate its potential importance at global scales

Facing drought in a Mediterranean post-fire community: tissue water relations in species with different life traits.

Bulk shoot water potential, the osmotic component and the bulk modulus of elasticity were measured throughout one growing season in four species co-occurring in a post-fire Mediterranean community in southern Italy: Pinus halepensis, Phillyrea latifolia, Cistus salvifolius and Rosmarinus officinalis. A severe drought occurred throughout the measurement period. Large seasonal fluctuations have been observed for both predawn and afternoon water potential in all species. Although minimum values down to –4 MPa have been measured, plant water potential always recovered to less negative values after drought. Daily amplitude of water potential decreased with increasing plant water stress in all species. In Cistus and Rosmarinus less ability for short-term control of plant water status has been assessed. Osmotic potential at full turgor did not display clear seasonal patterns, with no consistent ranking of species by their osmotic values. In most cases, no osmotic adjustment (lowering of osmotic potentials) and no change in tissue elastic properties were observed in response to increasing summer drought and intensity of water stress

XLA Petiole Index: A Novel Hydraulic Function Metric for Interpreting Drought-Induced Dieback in Mediterranean Ring-Porous Oak Forests

Climate-induced forest mortality is an increasing global phenomenon occurring at both regional and local scales, with implications for ecosystem functioning and the provision of essential ecosystem services. In recent years, the Italian peninsula has experienced widespread oak forest decline, with forests showing increased susceptibility to severe heat waves and prolonged droughts. Our study examined a drought-induced tree mortality episode in the Mediterranea region (Pollino National Park, Southern Italy) focusing on deciduous oak forest stands (Quercus frainetto Ten.). We employed a comprehensive approach, combining ecophysiological and dendro-ecological analyses to compare non-decaying (ND) and decaying (D) coexisting trees. Recent advancements in understanding the relationship between petiole xylem anatomy and leaf form and function have revealed a positive correlation between petiole vessel diameter and leaf size, both within and across species. Leaf petioles, serving as the singular entry point for water into the leaf venation system, offer a standardized basis for comparing xylem investment with downstream transpirational demands. To quantify this relationship, we employed a novel index derived from quantitative wood anatomy of petioles. This integrative trait characterizes leaf water transport function by measuring the ratio of cross-sectional xylem area (XA) at the petiole to the downstream leaf area, termed the XLA petiole Index. Our assessment of XLA petiole variation can provide evidence supporting a safety-efficiency trade-off in oak leaves, a crucial aspect of plant hydraulic strategy

Preliminary observations on haemodynamics during physiological stress conditions following 'double-orifice' mitral valve repair

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