Diagrammatic Gestures. Cognition, Mathematics, and Semiotics.

here are words having an extraordinary evocative power. This is precisely the case of “Diagram” and “Gesture”. The frst term covers an interconnected network of concepts like “graph”, “schema”, “form”, “model”, “arrow”, and so on... And the same can be said of the second one: just think, for example, of the ideas of “movement”, “bodily action”, “practical activity” or, more generally, of “doing”. Accounting for them has been, over the last 50 years, the aim of signifcant portions of the work conduction in philosophy (Deleuze, Foucault, Merleau-Ponty), mathematics (Grothendieck, Lawvere, Thom), semiotics (Peirce), and theoretical linguistics (Culioli, Langacker, Pottier). The present issue aims to present the state of the art with regard to the diagrammatic gesture, in particular by taking into account the relations between the disciplines mentioned and the arts and sciences

Sistemi di tariffe di cubatura per le fustaie di pino d’aleppo, pino laricio e pino domestico della Sicilia

The aim of this study is to set up one-way volume table series to predict stem volume of the main conifers in Sicily, namely Italian stone pine, Aleppo pine and Corsican pine. For each species the relationships between height and tree diameter at breast height (dbh) resulted well represented by the semilogarithmic function, which was established as «guide line» of the height-diameter relationship. Adapting each height - dbh series according to the inclination of the «guide line», a set of isomorphic height curves was obtained for each species. Corresponding volume series was obtained from each height series on the basis of National Forestry Inventory volume tables. Oneway volume table series are of considerable usefulness in the context of forest management since they represent estimation tools with flexible application at different levels of forest management

effect of environmental conditions on the durability of polycarbonate for the protection of cultural heritage sites

Polycarbonate is a good material for covering and protecting cultural heritage sites because of its durability, mechanical properties, and transparency. However, polycarbonate degrades under environmental weathering with a significant decrease of physical and mechanical properties and loss of transparency. In this work, the contemporary presence of ultraviolet irradiation and different temperature and moisture conditions have been taken into account to study the environmental degradation of this polymer with regard to its mechanical and optical properties. The photo-oxidation reactions cause a decrease in the molecular weight and the formation of many oxygenated species. The hydrolytic scission, instead, gives rise to a remarkable reduction in the molecular weight. These two different degradation mechanisms do not seem interconnected because at the lowest degradation temperature and high humidity levels, the reduction of the molecular weight is more pronounced than that observed at the highest temperature but at a lower humidity level. Transparency decreases with the degradative processes, but even after severe degradation the loss of transparency is only about 10%. The yellowness index increases during the first stages of degradation, which has been attributed to the fast formation of carbonyl groups due to photo-oxidation

effect of cold drawing on mechanical properties of biodegradable fibers

The use of biodegradable polymers is increasingly attracting interest over the last years, since they can reduce the environmental effects related to disposal of traditional plastics and, in general, the use of fossil, non-renewable resources. One of the most promising applications is represented by fibers production. However, the orientation and the crystallinity degrees can significantly affect the mechanical properties. Therefore, it is of interest to investigate on the optimum processing conditions, in order to improve the mechanical properties. In particular, while crystallinity can be slightly modified by the processing, orientation can be significantly improved. In this work, the effects of hot stretching on the mechanical and structural properties of fibers made from two different families of biodegradable blends were investigated. The orientation proved to significantly change the mechanical properties, and it was shown that factors such as the different relaxation times, the different crystallization temperatures and the cooling rate can give opposite effects in the three investigated polymer systems with significant consequences on the mechanical behaviour of the fibers. In particular, the behaviour during fiber production in hot stretching, and the orientation mechanisms were studied and explained on the basis of rheological and thermal properties of the polymers

The ecology of the cork-oark (Quercus suber L.) stands in NW Sicily

The uneven presence of the cork oak (Quercus suber L.) within its distribution range seems to be affected not only by its climatic requirements but also by rather specific edaphic needs. In fact, most of the known populations throughout the Mediterranean area thrive on acidic soils deriving from metamorphic or volcanic rock outcrops. However, some Italian populations of this species behave as if they were independent on the chemical and physical characteristics of the substrate, e.g. growing on calcareous soils, which are considered less suitable. This is the case of some populations in central Italy (Latium) and NW Sicily (Trapani Mts. and Palermo Mts.). A multidisciplinary investigation carried out on Palermo Mts. allowed: 1) to update the knowledge on the distribution of Q. suber in NW Sicily; 2) to verify that those populations are autochthonous; 3) to analyze and describe the soils and the plant communities linked with cork oaks; 4) to detect the ecological factors which could explain their local adaptation to calcareous soils; 5) to show the ecological, structural and dynamic role played by this species within the natural vegetation of Palermo Mts. The local presence of Q. suber stands may depend on three (perhaps synergic) factors: 1) the high fire frequency, which indirectly favours Q. suber by biasing the progressive succession towards the most common patterns of woodland, i.e. Q. ilex/Q. pubescens s.l. mixed forests; 2) the peculiar biogeochemistry of local soils; 3) the erosion that intermixed different parent materials

Effect of a compatibilizer on the morphology and properties of polypropylene/polyethylentherephthalate spun fibers

Fibers spun by melt spinning of binary and ternary polypropylene/ polyethylenetherephthalate blends have been produced and characterized in order to investigate the effect of a compatibilizer on their morphology and mechanical properties. The compatibilizer was a maleic anhydride-functionalized rubber copolymer. The effect of the compatibilizer was well evident in the isotropic state, as the morphology became very fine, the size of the dispersed particles was very small, and the adhesion was better. The effect of the compatibilizer on the mechanical properties is very relevant, especially in the elongation at break. On the contrary, no relevant effect was observed in the anisotropic oriented fibers. Although the average diameter of the microfibrils of the dispersed phase of the compatibilized blend generated during the hot drawing was much smaller than that of the microfibrils of the same particles of the uncompatibilized blend, the mechanical properties were almost the same. This behavior has been attributed to the length of the smaller microfibrils of the ternary blends, which was lower that of the microfibrils of the binary blend. This has been explained in terms of reduced initial droplet size, and therefore of lesser possibility of stretching the droplets to very long fibrils in these samples

Mechanical, thermomechanical and reprocessing behavior of green composites from biodegradable polymer and wood flour

The rising concerns in terms of environmental protection and the search for more versatile polymer-based materials have led to an increasing interest in the use of polymer composites filled with natural organic fillers (biodegradable and/or coming from renewable resources) as a replacement for traditional mineral inorganic fillers. At the same time, the recycling of polymers is still of fundamental importance in order to optimize the utilization of available resources, reducing the environmental impact related to the life cycle of polymer-based items. Green composites from biopolymer matrix and wood flour were prepared and the investigation focused on several issues, such as the effect of reprocessing on the matrix properties, wood flour loading effects on virgin and reprocessed biopolymer, and wood flour effects on material reprocessability. Tensile, Dynamic-mechanical thermal (DMTA), differential scanning calorimetry (DSC) and creep tests were performed, pointing out that wood flour leads to an improvement of rigidity and creep resistance in comparison to the pristine polymer, without compromising other properties such as the tensile strength. The biopolymer also showed a good resistance to multiple reprocessing; the latter even allowed for improving some properties of the obtained green composites

Compatibilization of Polypropylene/Polyamide 6 Blend Fibers Using Photo-Oxidized Polypropylene

The use of polyamide/polyolefin blends has gained importance and concern for years, but they also show some issues to be adequately addressed, such as the incompatibility between the two components. This is usually overcome by using suitable compatibilizers, typically based on functionalized polyolefins. However, there is only little information about the use of a degraded polyolefins to induce compatibilization. This is even truer, as far as polyamide 6/polypropylene (PA6/PP) blends are concerned. In this work, compatibilization of PA6/PP blends by using small amounts of photo-oxidized PP was investigated; furthermore, the effects due to the presence of the photo-oxidized PP were studied also in relationship to the spinning operation, where the existence of the non-isothermal elongational flow can lead to significant, further morphological changes. It was found that isotropic samples showed significant enhancements of the tensile properties upon adding the photo-oxidized PP. Under non-isothermal elongational flow conditions, the presence of the photo-oxidized PP was particularly effective in improving the mechanical properties in comparison to the uncompatibilized blend fibers. Furthermore, an important result was found: The elongational-flow processing allowed obtaining anisotropic samples where the improvements of the properties, in comparison to the isotropic samples, were similar to those achieved by using a compatibilizer

The Human MDM2 Oncoprotein Increases the Transcriptional Activity and the Protein Level of the p53 Homolog p63

Genetic alteration of the p53 tumor suppressor gene, which monitors DNA damage and operates cell cycle checkpoints, is a major factor in the development of human malignancies. The p53 protein belongs to a family that also includes two structurally related proteins, p63 and p73. Although all three proteins share similar transcriptional functions and antiproliferative effects, each of them appears to play a distinct role in development and tumor suppression. One of the principal regulators of p53 activity is the MDM2 protein. The interaction of MDM2 with p53 inhibits p53 transcriptional activity and targets p53 for ubiquitin-dependent degradation. The ability of MDM2 to inhibit p53 functions is antagonized by the ARF oncosuppressor protein. We show here that like p53, the p63alpha and p63gamma isoforms are able to associate with human MDM2 (HDM2). Overexpression of HDM2 increased the steady-state level of intracellular p63 and enhanced its transcriptional activity. Both effects appeared to be counteracted by ARF coexpression. These data indicate that p63 can be activated by HDM2 under conditions in which p53 is inhibited. Therefore, HDM2 expression could support p63-specific transcriptional functions on a common set of genes, keeping interference by p53 at a minimum