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Search Results: 1 - 10 of 175616 matches for " Giorgio de; "
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O programa piloto para prote??o das florestas tropicais do Brasil (PPG-7) e a globaliza??o da Amaz?nia
Antoni, Giorgio De;
Ambiente & Sociedade , 2010, DOI: 10.1590/S1414-753X2010000200006
Abstract: the ppg-7, developed from 1994 to 2009, acquires a special significance by making the transition of a conservationist ideology to the introduction of market economy in the amazon region. the proposal of g-7 and the acceptance of the brazilian government at that time sought to integrate the initiative within the new international scenario, initiating the current mercantile process of the amazon.
Reliability Testing Procedure for MEMS IMUs Applied to Vibrating Environments
Giorgio De Pasquale,Aurelio Somà
Sensors , 2010, DOI: 10.3390/s100100456
Abstract: The diffusion of micro electro-mechanical systems (MEMS) technology applied to navigation systems is rapidly increasing, but currently, there is a lack of knowledge about the reliability of this typology of devices, representing a serious limitation to their use in aerospace vehicles and other fields with medium and high requirements. In this paper, a reliability testing procedure for inertial sensors and inertial measurement units (IMU) based on MEMS for applications in vibrating environments is presented. The sensing performances were evaluated in terms of signal accuracy, systematic errors, and accidental errors; the actual working conditions were simulated by means of an accelerated dynamic excitation. A commercial MEMS-based IMU was analyzed to validate the proposed procedure. The main weaknesses of the system have been localized by providing important information about the relationship between the reliability levels of the system and individual components.
Nitrogen fertilization and root growth dynamics of durum wheat for a sustainable production
Donato De Giorgio,Francesco Fornaro
Italian Journal of Agronomy , 2012, DOI: 10.4081/ija.2012.e29
Abstract: In an area of the Apulian Tavoliere (southern Italy), the effects of three levels of nitrogen fertilization (0, 50 and 100 kg N ha–1) on root development, growth analysis and yield parameters of durum wheat were evaluated. The research was conducted over a four-year period (1994-97). The non-destructive mini-rhizotron method was used to study the root system at stem extension and at the beginning of heading and ripening stages. At the end of tillering and at boot and flowering stages, samples of wheat biomass were taken and subjected to growth analysis. Yield data and the main biometric parameters were collected at harvest time. The doses of nitrogen (N) fertilizer 50 and 100 kg N ha–1 had a greater effect on root development in the 20-30 cm soil layer and on epigeal biomass than the control test (N0) without nitrogen fertilization. In the test (N0) the growth of root and epigeal biomass was slower during the first vegetative phases, however, afterwards both of them recovered and the root system was mainly developed in the 30-40 cm soil layer. A better development of root system in deeper soil layers, without nitrogen supply, has allowed the plant to overcome more easily the water-deficit and thermal stresses during the ripening stage. The results of this research have shown that the production of grain with 50 kg ha–1 of N is similar to those of 100 kg ha–1 of N doses and higher than the test without nitrogen fertilization. In this kind of environment can be recommended a nitrogen dose of 50 kg ha–1 for obtaining an increase in grain production with low costs and reduced agricultural sources of pollution.
Ictal but Not Interictal Epileptic Discharges Activate Astrocyte Endfeet and Elicit Cerebral Arteriole Responses
Marco de Curtis,Giorgio Carmignoto
Frontiers in Cellular Neuroscience , 2011, DOI: 10.3389/fncel.2011.00008
Abstract: Activation of astrocytes by neuronal signals plays a central role in the control of neuronal activity-dependent blood flow changes in the normal brain. The cellular pathways that mediate neurovascular coupling in the epileptic brain remain, however, poorly defined. In a cortical slice model of epilepsy, we found that the ictal, seizure-like discharge, and only to a minor extent the interictal discharge, evokes both a Ca2+ increase in astrocyte endfeet and a vasomotor response. We also observed that rapid ictal discharge-induced arteriole responses were regularly preceded by Ca2+ elevations in endfeet and were abolished by pharmacological inhibition of Ca2+ signals in these astrocyte processes. Under these latter conditions, arterioles exhibited after the ictal discharge only slowly developing vasodilations. The poor efficacy of interictal discharges, compared with ictal discharges, to activate endfeet was confirmed also in the intact in vitro isolated guinea pig brain. Although the possibility of a direct contribution of neurons, in particular in the late response of cerebral blood vessels to epileptic discharges, should be taken into account, our study supports the view that astrocytes are central for neurovascular coupling also in the epileptic brain. The massive endfeet Ca2+ elevations evoked by ictal discharges and the poor response to interictal events represent new information potentially relevant to interpret data from diagnostic brain imaging techniques, such as functional magnetic resonance, utilized in the clinic to localize neural activity and to optimize neurosurgery of untreatable epilepsies.
Alterations of Neocortical Pyramidal Neurons: Turning Points in the Genesis of Mental Retardation
Alberto Granato,Andrea De Giorgio
Frontiers in Pediatrics , 2014, DOI: 10.3389/fped.2014.00086
Abstract: Pyramidal neurons (PNs) represent the majority of neocortical cells and their involvement in cognitive functions is decisive. Therefore, they are the most obvious target of developmental disorders characterized by mental retardation. Genetic and non-genetic forms of intellectual disability share a few basic pathogenetic signatures that result in the anomalous function of PNs. Here, we review the key mechanisms impairing these neurons and their participation in the cortical network, with special focus on experimental models of fetal exposure to alcohol. Due to the heterogeneity of PNs, some alterations affect selectively a given cell population, which may also differ depending on the considered pathology. These specific features open new possibilities for the interpretation of cognitive defects observed in mental retardation syndromes, as well as for novel therapeutic interventions.
Phase behavior of wormlike rods
Giorgio Cinacchi,Luca De Gaetani
Physics , 2007, DOI: 10.1103/PhysRevE.77.051705
Abstract: By employing Molecular Dynamics computer simulations, the phase behavior of systems of rodlike particles with varying degree of internal flexibility has been traced from the perfectly rigid rod limit till very flexible particles, and from the high density region till the isotropic phase. From the perfectly rigid rod limit and enhancing the internal flexibility, the range of the smectic A phase is squeezed out by the concomitant action of the scarcely affected crystalline phase at higher density and the nematic phase at lower density, until it disappears. These results confirm the supposition, drawn from previous theoretical, simulational and experimental studies, that the smectic A phase is destabilized by introducing and enhancing the degree of particle internal flexibility. However, no significant changes in the order of nematic--to--smectic A phase transition, which appears always first order, nor in the value of the layer spacing, are observed upon varying the degree of particle internal flexibility. Moreover, no evidence of a columnar phase, which was tought of as a possible superseder of the smectic A phase in flexible rods, has been obtained.
A Stochastic Partially Reversible Investment Problem on a Finite Time-Horizon: Free-Boundary Analysis
Tiziano De Angelis,Giorgio Ferrari
Mathematics , 2013,
Abstract: We study a continuous-time, finite horizon, stochastic partially reversible investment problem for a firm producing a single good in a market with frictions. The production capacity is modeled as a one-dimensional, time-homogeneous, linear diffusion controlled by a bounded variation process which represents the cumulative investment-disinvestment strategy. We associate to the investment-disinvestment problem a zero-sum optimal stopping game and characterize its value function through a free-boundary problem with two moving boundaries. These are continuous, bounded and monotone curves that solve a system of non-linear integral equations of Volterra type. The optimal investment-disinvestment strategy is then shown to be a diffusion reflected at the two boundaries.
Problemas fitogeográficos de S?o José do Rio Preto, estado de S?o Paulo, Brasil
Marinis, Giorgio de;Camargo, Paulo Nogueira de;
Anais da Escola Superior de Agricultura Luiz de Queiroz , 1966, DOI: 10.1590/S0071-12761966000100013
Abstract: the county of s?o josé do rio preto, state of s?o paulo, brazil, whose climatic and pedological characteristics are referred in this paper, has a reduced and fragmentary area of natural forests, which is mostly occupied by somewhat savanized and, in less grade, ruderalized formations. from the second half of 1962 to the end of 1963, the authors have found species belonging to five different phytogeographic elements, as follow: the general element, the amazonic element, the atlantic element, the meridional element, and the central element. though no secure] statement can one make on the climax-formation of the region, we may admit that it might be the semideciduous and somewhat xeromorphic latifoliated tropical forest. the problem of origin of the "cerrado" remains an open question yet.
Using of Particle Swarm for Performance Optimization of Helicopter Rotor Blades  [PDF]
Giorgio Guglieri
Applied Mathematics (AM) , 2012, DOI: 10.4236/am.2012.330197
Abstract: As part of a research activity at Politecnico di Torino, aiming to develop multi-disciplinary design procedures implementing nature inspired meta-heuristic algorithms, a performance design optimization procedure for helicopter rotors has been developed and tested. The procedure optimizes the aerodynamic performance of blades by selecting the point of taper initiation, the root chord, the taper ratio, and the maximum twist which minimize horsepower for different flight regimes. Satisfactory aerodynamic performance is defined by the requirements which must hold for any flight condition: the required power must be minimized, both the section drag divergence Mach number on the advancing side of the rotor disc and the maximum section lift coefficient on the retreating side of the rotor disc must be avoided and, even more important, the rotor must be trimmed. The procedure uses a comprehensive mathematical model to estimate the trim states of the helicopter and the optimization algorithm consists of a repulsive particle swarm optimization program. A comparison with an evolutionary micro-genetic algorithm is also presented.
A Note on the Guignard Constraint Qualification and the Guignard Regularity Condition in Vector Optimization  [PDF]
Giorgio Giorgi
Applied Mathematics (AM) , 2013, DOI: 10.4236/am.2013.44101
Abstract:

Some remarks are made on the use of the Abadie constraint qualification, the Guignard constraint qualifications and the Guignard regularity condition in obtaining weak and strong Kuhn-Tucker type optimality conditions in differentiable vector optimization problems.

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