267 research outputs found

    Studio di fattibilità per lo sviluppo di una filiera legno-energia in Valle Stura di Demonte (Cuneo, Italia)

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    Il progetto di cooperazione italo-francese Accordo, il quale aveva come obiettivo lo sviluppo di una filiera legno energia sul territorio dei Pays de Haute Provence, in Francia, e della Comunità Montana Valle Stura, in Italia, ha portato alla costituzione di un partenariato sia istituzionale che tecnico. In questo articolo il partner tecnico italiano, l’IPLA - Istituto per le Piante da Legno e per l’Ambiente, ci descrive la fase di analisi preliminare del territorio italiano, lche ha permesso di descrivere il bacino di approvvigionamento di riferimento e di avviare proposte per la sua gestione

    Opportunities for coppice management at the landscape level: the Italian experience

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    Coppice silviculture has a long tradition in Italy. Societal demands have led to the development of forest management techniques for integrating wood production with other kinds of forest uses and regulations have been issued to limit forest degradation. In Italy, 35% of the national forest cover is currently managed under coppice silvicultural systems that provide 66% of the annual wood production. Fuel-wood demand is increasing and a large amount of fuelwood is currently imported in Italy. Modern coppice practices differ from those adopted in the past and may have a reduced impact on ecosystem characteristics and processes. Nevertheless, coppice silviculture has a bad reputation mostly on grounds that are beyond economic, technical and ecological rationales. Neither cessation of use nor a generalized conversion from coppice to high forest are likely to respond simultaneously to the many demands deriving from complex and articulated political and economic perspectives operating at global, European, national, regional and forest stand-level scales. Different approaches of modern silviculture to coppice successfully tested in Italy for more than a decade are illustrated. We propose to combine different options at the stand and sub-stand level, including either development without human interference or conversion to high forest, and to apply these approaches within the framework of novel forest management plans and regionally consistent administrative procedures. This bottom-up approach represents a potential solution to the socio-economic and environmental challenges affecting coppicing as a silvicultural system

    Nanomaterials for Neural Interfaces

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    This review focuses on the application of nanomaterials for neural interfacing. The junction between nanotechnology and neural tissues can be particularly worthy of scientific attention for several reasons: (i) Neural cells are electroactive, and the electronic properties of nanostructures can be tailored to match the charge transport requirements of electrical cellular interfacing. (ii) The unique mechanical and chemical properties of nanomaterials are critical for integration with neural tissue as long-term implants. (iii) Solutions to many critical problems in neural biology/medicine are limited by the availability of specialized materials. (iv) Neuronal stimulation is needed for a variety of common and severe health problems. This confluence of need, accumulated expertise, and potential impact on the well-being of people suggests the potential of nanomaterials to revolutionize the field of neural interfacing. In this review, we begin with foundational topics, such as the current status of neural electrode (NE) technology, the key challenges facing the practical utilization of NEs, and the potential advantages of nanostructures as components of chronic implants. After that the detailed account of toxicology and biocompatibility of nanomaterials in respect to neural tissues is given. Next, we cover a variety of specific applications of nanoengineered devices, including drug delivery, imaging, topographic patterning, electrode design, nanoscale transistors for high-resolution neural interfacing, and photoactivated interfaces. We also critically evaluate the specific properties of particular nanomaterials—including nanoparticles, nanowires, and carbon nanotubes—that can be taken advantage of in neuroprosthetic devices. The most promising future areas of research and practical device engineering are discussed as a conclusion to the review.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/64336/1/3970_ftp.pd

    Waves, Pulses, and the Theory of Neural Masses

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     It is a truism that systems as complex as vertebrate nervous systems are more than the sum of their parts. What is meant is that the interconnection of numbers of neurons gives rise to collective properties belonging to the neural populations and not to the neurons taken one at a time. The purpose of this essay is to explore some facets of the nature of neural collective properties.   Conventional wisdom holds that such properties emerge from the interconnection of finite numbers of neurons in discrete chains and networks, which are logical and anatomical counterparts of the Jacksonian-Sherringtonian heirarchy of reflex arcs. According to a popular analogy, neurons are like the electronic components of a television receiver which can be connected in a certain way or set of ways to give the properties of the receiver. The central thesis of this essay is the idea that, when neurons strongly interact in sufficiently large numbers (on the order of 10' or more), new collective properties emerge that demand a different kind or level of conceptualization.   An analogy equivalent to that given above is the notion that temperature and pressure exist only for a mass, in contrast to the thermal kinetic energy of molecules in the mass. The suggestion is that certain interactive phenomena in vertebrate brains occur only as broadly distributed and continuous events or waves across masses of neurons, and that in some instances these cooperative phenomena may be essential aspects of normal brain function. The task is to describe some of these wave phenomena in terms of underlying collective properties, and to do so in such a way as to minimize confusion between observables and principles. Again by analogy, brain potentials (EEG waves) appear to have somewhat the relation to wave activity of neural masses that flow patterns have to temperature and pressure waves in atmospheric storms. They are observable side effects that are of interest mainly because they give access to the internal dynamics.   The approach used is to review the historical interplay between ideas concerning neural networks and masses, to develop a set of rules for describing neural masses as dynamic entities, and then to discuss some of the implications of those rules for neurophysiology.   Throughout the development the emphasis is placed on the idea of graded neural synaptic interaction, because it is interaction of neurons that gives rise to something more than the sum of parts. Neurons are connected to each other by structural synaptic linkages. For each neuron there is a certain density of these anatomical connections, referring to the number and size of contacts of each neuron with its neighbors within each unit volume of neural mass. But the significant quantity is the momentary functional or effective connection density, which denotes the level of transfer of influence across a given set of connections at a given time and place. If, for example, a volley arrives on an afferent path to a neuron that is in an absolute refractory state, the functional connection density is zero, even though the anatomical connection density is nonzero.   Two kinds of massive connections are distinguished. The first is a one-way or forward connection from one neuron to neurons in another mass; the second is feedback connection of one neuron with many others in the same mass. Both types give rise to mass actions of many neurons, but only the second gives rise to the collective properties of interest in the present context. That is, neural interactions based on functional interconnection densities give rise to wave phenomena, and, as is shown for some of the neural masses in the mammalian olfactory system, the observable effects of wave patterns in turn provide the means for measuring the intensities of interactions

    Excitation et inhibition du tétanos strychnique chez le chat curarisé

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    SCOPUS: ar.jinfo:eu-repo/semantics/publishe
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