Damage-cluster distributions and size effect on strength in compressive failure

We investigate compressive failure of heterogeneous materials on the basis of a continuous progressive damage model. The model explicitely accounts for tensile and shear local damage and reproduces the main features of compressive failure of brittle materials like rocks or ice. We show that the size distribution of damage-clusters, as well as the evolution of an order parameter, the size of the largest damage-cluster, argue for a critical interpretation of fracture. The compressive failure strength follows a normal distribution with a very small size effect on the mean strength, in good agreement with experiments

Parallel Algorithm and Dynamic Exponent for Diffusion-limited Aggregation

A parallel algorithm for ``diffusion-limited aggregation'' (DLA) is described and analyzed from the perspective of computational complexity. The dynamic exponent z of the algorithm is defined with respect to the probabilistic parallel random-access machine (PRAM) model of parallel computation according to $T \sim L^{z}$, where L is the cluster size, T is the running time, and the algorithm uses a number of processors polynomial in L\@. It is argued that z=D-D_2/2, where D is the fractal dimension and D_2 is the second generalized dimension. Simulations of DLA are carried out to measure D_2 and to test scaling assumptions employed in the complexity analysis of the parallel algorithm. It is plausible that the parallel algorithm attains the minimum possible value of the dynamic exponent in which case z characterizes the intrinsic history dependence of DLA.Comment: 24 pages Revtex and 2 figures. A major improvement to the algorithm and smaller dynamic exponent in this versio

Facing metal stress by multiple strategies: morphophysiological responses of cardoon (Cynara cardunculus L.) grown in hydroponics

The contamination of environments by heavy metals has become an urgent issue causing undesirable accumulations and severe damages to agricultural crops, especially cadmium and lead which are among the most widespread and dangerous metal pollutants worldwide. The selection of proper species is a crucial step in many plant-based restoration approaches; therefore, the aim of the present work was to check for early morphophysiological responsive traits in three cultivars of Cynara cardunculus (Sardo, Siciliano, and Spagnolo), helping to select the best performing cultivar for phytoremediation. For all three tested cultivars, our results indicate that cardoon displays some morphophysiological traits to face Cd and Pb pollution, particularly at the root morphology level, element uptake ability, and photosynthetic pigment content. Other traits show instead a cultivar-specific behavior; in fact, stomata plasticity, photosynthetic pattern, and antioxidant power provide different responses, but only Spagnolo cv. achieves a successful strategy attaining a real resilience to metal stress. The capacity of Spagnolo plants to modify leaf structural and physiological traits under heavy metal contamination to maintain high photosynthetic efficiency should be considered an elective trait for its use in contaminated environments

Anthocyanins are Key Regulators of Drought Stress Tolerance in Tobacco

Abiotic stresses will be one of the major challenges for worldwide food supply in the near future. Therefore, it is important to understand the physiological mechanisms that mediate plant responses to abiotic stresses. When subjected to UV, salinity or drought stress, plants accumulate specialized metabolites that are often correlated with their ability to cope with the stress. Among them, anthocyanins are the most studied intermediates of the phenylpropanoid pathway. However, their role in plant response to abiotic stresses is still under discussion. To better understand the effects of anthocyanins on plant physiology and morphogenesis, and their implications on drought stress tolerance, we used transgenic tobacco plants (AN1), which over-accumulated anthocyanins in all tissues. AN1 plants showed an altered phenotype in terms of leaf gas exchanges, leaf morphology, anatomy and metabolic profile, which conferred them with a higher drought tolerance compared to the wild-type plants. These results provide important insights for understanding the functional reason for anthocyanin accumulation in plants under stress

Professione designer under 35 in Piemonte

La ricerca “Professione designer under 35 in Piemonte" nasce all'interno di MIRA Osservatorio regionale del design promosso dal Circolo del Design di Torino ed è stata curata da ricercatori del Dipartimento di Economia e Statistica “Cognetti de Martiis” dell’Università degli Studi di Torino e del Dipartimento di Architettura e Design del Politecnico di Torino, con la collaborazione di Fondazione Santagata per l’Economia della Cultura. Due sono gli obiettivi dell'analisi: dedicare uno studio in dettaglio sulle condizioni professionali relative a quel segmento di fascia d’età di lavoratori che in Italia fatica maggiormente ad inserirsi nel mondo del lavoro e a trovare gratificazioni e remunerazioni adeguate; tracciare direzioni politiche a sostegno dell'attività di design nel periodo post formazione

Economia del Design in Piemonte 2022

La ricerca “Economia del Design in Piemonte 2022” nasce all'interno di MIRA Osservatorio regionale del design promosso dal Circolo del Design di Torino ed è stata curata da ricercatori del Dipartimento di Economia e Statistica “Cognetti de Martiis” dell’Università degli Studi di Torino e del Dipartimento di Architettura e Design del Politecnico di Torino, con la collaborazione di Fondazione Santagata per l’Economia della Cultura. Costituisce una fotografia aggiornata dell’economia regionale relativa al design come risorsa strategica, che evolve nel tempo come attività trasversale e che può essere colta attraverso percorsi di analisi continuativi e dinamici per intercettare le nuove traiettorie di sviluppo e intersezione. Tre sono le originali traiettorie di analisi che hanno permesso di valutare l’ecosistema economico regionale del design: il Core Design che comprende le imprese che offrono progettazione di design come core busines; il Design Driven che comprende imprese che utilizzano il design come input caratterizzante la propria offerta e il Design Hidden, ovvero quelle imprese che utilizzano il design come input aggiuntivo nello svolgimento delle proprie attività

Fractal to Nonfractal Phase Transition in the Dielectric Breakdown Model

A fast method is presented for simulating the dielectric-breakdown model using iterated conformal mappings. Numerical results for the dimension and for corrections to scaling are in good agreement with the recent RG prediction of an upper critical $\eta_c=4$, at which a transition occurs between branching fractal clusters and one-dimensional nonfractal clusters.Comment: 5 pages, 7 figures; corrections to scaling include