86,633 research outputs found
ASTRONET
No full textRete informatica per l'astrofisica italiana ed implementazione del nodo di calcolo presso il Laboratorio di astrofisica di Lecce
Progetto Nazionale Astronet
No full textCreazione di una rete informatica e per il calcolo per in astrofisica
Influenza della posizione della foglia-talea sul ramo e di trattamenti auxinici sul radicamento di talee di Ficus elastica.
No full textPower-Law Inflation
No full textThe outstanding cosmological problems (horizon, flatness, . . .) which may be solved by the usual inflationary models may also find a solution in the frame of a ``generalized'' inflationary cosmology which is characterized by a suitable phase of accelerated expansion. The usual exponential growth of the scale factor S is just a particular case of such a general idea. Following this line of thought, we study in some detail a simple inflationary model characterized by a scale factor which grows like S~tp, with p a constant greater than one, which we call power-law inflation (PLI). Some properties of PLI have been analyzed, in different contexts, also by other authors. We consider the constraints on this model coming from the requirement of solving the horizon, flatness, ``good'' reheating, and ``convenient'' perturbation-spectrum problems. In order to obtain the perturbation spectrum when re-entering the horizon during the Friedmann phase, we extend to PLI the gauge-invariant approach developed by Bardeen et al. for the usual inflationary models. We find that the above constraints can be suitably satisfied. Finally, we outline possible connections between PLI and particular inflationary models which have recently been proposed
Valorization of a Veneto grapevine germoplasm collection by molecular characterization and biochemical analysis of resveratrol compounds
No full textGrapevine is the most important perennial crop worldwide. The world’s collections of grape plant material are estimated to contain about 12000–15.000 cultivars. Many of these are ancient and autochthonous cultivars still not registered in the ampelographic national catalogues and therefore risking the extinction. In order to safeguard this germplasm a correct classification solving the problems of synonymous and homonymous in the cultivar designations is requested.
The identification and comparison of plant material by ampelographic methods is liable to misinterpretations, while DNA-based markers provide a more reliable alternative for cultivar identification. To preserve the genetic variability of local germplasm we initiate the characterization of 30 North-Eastern cultivars at 23 microsatellite loci. The markers were proved to be informative in the grapevine cultivars. The genetic profiles of all 30 cultivars were searched for possible parent-offspring groups and several cases of suspected synonyms have been investigated.
The valorization of this germplasm was implemented by biochemical analysis of resveratrol (trans-3, 4 , 5-trihydroxystilbene) content. This stilbenic compound is a phytoalexin protecting grapevine against fungal infections. The recent years have also witnessed intense research aimed to clarify the role of stilbenes (that are also present in wines) and, among them, resveratrol, in human health because of their protective effects against cardiac decompensation and cancer. The potential therapeutic value of resveratrol has stimulated research activities on the occurrence of this molecules in grapes and wines
Kinematical Properties of Generalized Inflation
No full textThe kinematical properties of Robertson-Walker models which allow a solution of the cosmological horizon and flatness problems are studied: these are called models of generalized inflation. A useful illustration of such inflation is considered in which the background equation of state assumes the form p/ρ = const. < - 1/3. In this context we also discuss a possible solution of the Ω-problem. The general properties of the spectrum of tensor and scalar perturbations generated during the inflationary phase are analyzed. Finally we discuss some examples of generalized inflation which occur mainly in the frame of some recently proposed models of Kaluza-Klein cosmology
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