238 research outputs found

    Local identity and technological innovation. Urban and territorial policies for the re-interpretation of the historical center of Sadali (Sardinia)

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    The aim of this study is to propose a technological urban regeneration method by applying innovative techniques of energy conservation to a local stone material of high landscape value, from the historical centre of Sadali (central Sardinia). Basic assumptions for this work are concepts of energy saving in buildings and use of local materials. The two main themes of research are the renovation of existing buildings according to local building materials and construction techniques whilst paying attention to comfort temperature and relative humidity of the building and the complete reconstruction of parts of buildings, or entire buildings, using new techniques and new structural solution, but always using the local stone to respect the building typology

    A Layered Architecture for Implementing Autonomous Planning Agents

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    This paper briefly describes an architecture for implementing autonomous agents that embody sophisticated planning capabilities. In particular, we are currently working on a two-pass vertically layered architecture, designed to deal with a complex environment. Such an architecture is currently based on three levels of abstraction (i.e., situated, strategic and deliberative), but has been designed for being easily generalized to a N-levels architecture, depending on the given environment and task complexity. Each level controls the underlying one, so that an agent behavior is supported by a clean hierarchical organization. Our autonomous agents act in a virtual world created for a computer game, and must interact with it by suitably planning and executing complex actions

    Higher and lower supramolecular orders for the design of self-assembled heterochiral tripeptide hydrogel biomaterials

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    The self-assembly behaviour of the eight stereoisomers of Val\u2013Phe\u2013Phe tripeptides under physiological conditions is assessed by several spectroscopy and microscopy techniques. We report the first examples of self-organised hydrogels from tripeptides in the L\u2013D\u2013L or D\u2013L\u2013D configuration, besides the expected gels with the D\u2013L\u2013L or L\u2013D\u2013D configuration, thus widening the scope for using amino acid chirality as a tool to drive self-assembly. Importantly, the positions of D- and L-amino acids in the gelling tripeptides determine a higher or lower supramolecular order, which translates into macroscopic gels with different rheological properties and thermal behaviours. The more durable hydrogels perform well in cytotoxicity assays, and also as peptides in solution. An appropriate design of the chirality of self-assembling sequences thus allows for the fine-tuning of the properties of the gel biomaterials. In conclusion, this study adds key details of supramolecular organization that will assist in the ex novo design of assembling chiral small molecules for their use as biomaterials

    Chronic Red Bull Consumption during Adolescence: Effect on Mesocortical and Mesolimbic Dopamine Transmission and Cardiovascular System in Adult Rats

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    Energy drinks are very popular nonalcoholic beverages among adolescents and young adults for their stimulant effects. Our study aimed to investigate the effect of repeated intraoral Red Bull (RB) infusion on dopamine transmission in the nucleus accumbens shell and core and in the medial prefrontal cortex and on cardiac contractility in adult rats exposed to chronic RB consumption. Rats were subjected to 4 weeks of RB voluntary consumption from adolescence to adulthood. Monitoring of in vivo dopamine was carried out by brain microdialysis. In vitro cardiac contractility was studied on biomechanical properties of isolated left-ventricular papillary muscle. The main finding of the study was that, in treated animals, RB increased shell dopamine via a nonadaptive mechanism, a pattern similar to that of drugs of abuse. No changes in isometric and isotonic mechanical parameters were associated with chronic RB consumption. However, a prolonged time to peak tension and half-time of relaxation and a slower peak rate of tension fall were observed in RB-treated rats. It is likely that RB treatment affects left-ventricular papillary muscle contraction. The neurochemical results here obtained can explain the addictive properties of RB, while the cardiovascular investigation findings suggest a hidden papillary contractility impairment

    Design of a hydrophobic tripeptide that self-assembles into amphiphilic superstructures forming a hydrogel biomaterial

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    We report the rational design of a heterochiral hydrophobic tripeptide self-assembling into amphiphilic D-superstructures that yield a self-supportive hydrogel at physiological pH. The material endures cell culture conditions and sustains fibroblast proliferation. Tripeptide superstructures are thoroughly analysed by several techniques

    Effective generation of closed-form soliton solutions of the continuous classical Heisenberg ferromagnet equation

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    The non-topological, stationary and propagating, soliton solutions of the classical continuous Heisenberg ferromagnet equation are investigated. A general, rigorous formulation of the Inverse Scattering Transform for this equation is presented, under less restrictive conditions than the Schwartz class hypotheses and naturally incorporating the non-topological character of the solutions. Such formulation is based on a new triangular representation for the Jost solutions, which in turn allows an immediate computation of the asymptotic behaviour of the scattering data for large values of the spectral parameter, consistently improving on the existing theory. A new, general, explicit multi-soliton solution formula, amenable to computer algebra, is obtained by means of the matrix triplet method, producing all the soliton solutions (including breather-like and multipoles), and allowing their classification and descriptio
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