Displaying similar documents to “La Logica dei Poliedri”

Calcoli generali con «tipi» e Logiche generalizzate

Piero Mangani (1984)

Atti della Accademia Nazionale dei Lincei. Classe di Scienze Fisiche, Matematiche e Naturali. Rendiconti

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In this paper we introduce a notion of "Generalized Logic" and we study some of its properties.

Calcoli generali con «tipi» e Logiche generalizzate

Piero Mangani (1984)

Atti della Accademia Nazionale dei Lincei. Classe di Scienze Fisiche, Matematiche e Naturali. Rendiconti Lincei. Matematica e Applicazioni

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In this paper we introduce a notion of "Generalized Logic" and we study some of its properties.

Gruppi di permutazioni e risultati di irrazionalità

Carlo Viola (2008)

Bollettino dell'Unione Matematica Italiana

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We recall some basic concepts in diophantine approximation, in particular the notion of irrationality measure. We describe the main aspects of the permutation group method due to G. Rhin and the author, with some arithmetical applications.

Algebre di Koszul

Aldo Conca (2008)

Bollettino dell'Unione Matematica Italiana

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The goal of the talk is to introduce and discuss the notion Koszul algebra in the commutative setting along with the associated notions of G-quadraticity and Koszul filtration. We present some results that appear in the papers [C, CTV, CRV] joint with M.E.Rossi, N.V.Trung and G.Valla. These results concern Koszul and G-quadratic properties of algebras associated with points, curves, cubics and spaces of quadrics of low codimension.

Ulteriori osservazioni sulla rigenerazione del mesencefalo in Xenopus laevis (Daudin). Istologia del tetto ottico normale e rigenerato

Sergio Filoni, Vito Margotta, Giancarlo Gibertini (1971)

Atti della Accademia Nazionale dei Lincei. Classe di Scienze Fisiche, Matematiche e Naturali. Rendiconti

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The histology of normal and regenerated optic lobes was examined in young specimens of Xenopus laevis by applying the Golgi-Cox method. In the operated animals the unilateral ablation of the optic lobe has been performed at the early larval stages (48-51) and at the later larval stages (55-56), according to Nieuwkoop and Faber. From our observations we drew the following conclusions: 1) The histological features of the optic tectum of Xenopus laevis are essentially similar to those of...

Discretizzazione di domini infiniti (elementi infiniti). Nota I

Gianmaria Donida, Luisa Tabusso (1980)

Atti della Accademia Nazionale dei Lincei. Classe di Scienze Fisiche, Matematiche e Naturali. Rendiconti

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A new technique for analysing problems which extend to infinity using elements is presented. A typical situation is that of the unbounded surface wave problems, either in two or three dimensions. The strategy is to discretize the inner domain in the standard finite element manner and to discretize the outer domain which extends to infinity with special infinite elements, for these elements are here suggested a series of shape functions analogous to Lagrange polynomials, but including...

Discretizzazione di domini infiniti (elementi infiniti). Nota II

Gianmaria Donida, Luisa Tabusso (1980)

Atti della Accademia Nazionale dei Lincei. Classe di Scienze Fisiche, Matematiche e Naturali. Rendiconti

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A new technique for analysing problems which extend to infinity using elements is presented. A typical situation is that of the unbounded surface wave problems, either in two or three dimensions. The strategy is to discretize the inner domain in the standard finite element manner and to discretize the outer domain which extends to infinity with special infinite elements, for these elements are here suggested a series of shape functions analogous to Lagrange polynomials, but including...

Sintesi di acidi ribonucleici e di proteine nelle diverse regioni dell'embrione di Xenopus laevis

Marisa Leonardi Cigada, Fiorenza Laria De Bernardi, Anna Maria Scarpetti Bolzern (1975)

Atti della Accademia Nazionale dei Lincei. Classe di Scienze Fisiche, Matematiche e Naturali. Rendiconti

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An analysis of RNA and protein synthesis has been carried out on Xenopus laevis embryos, cut into two portions, during the early stages of their development. Actinomycin D was employed to inhibit the synthesis. The action of actinomycin on synthesis is stronger during gastrulation than during neurulation. In each stage a correlation between RNA synthesis inhibition and protein synthesis inhibition has been observed. In the ventral fragments of the neurula the ratio between the two inhibitions...

Combinatoria e Topologia. Teorema di Quillen e funzioni di Möbius

Andrea Brini (2004)

Bollettino dell'Unione Matematica Italiana

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The notion of Galois Connections between partially ordered sets is introduced, together with a presentation of some of its main characterizations. This leads to a true understanding of the deep connection that links Galois Connections to Quillen’s Homotopy Type Equivalence Theorem. Furthermore, the notion of Möbius functions of finite lattices is discussed, in order to show its crucial role in Enumerative Combinatorics over Finite Posets and Discrete Probability Theory. Since the values...

Alcune considerazioni su una classe di sistemi del primo ordine quasi-lineari conservativi ed iperbolici di due equazioni in due variabili indipendenti

Domenico Fusco (1980)

Atti della Accademia Nazionale dei Lincei. Classe di Scienze Fisiche, Matematiche e Naturali. Rendiconti

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In this paper we determine a class of first order quasi-linear hyperbolic systems in conservative form involving two independent and two dependent variables which are not deducible, in general, from a variational principle but can be reduced to a Godunov’s symmetric form [5], [6] where the coefficient of the field spatial derivative is a constant matrix. That enables us to extend to these systems several results obtained by G. Boillat in [8], [9] and concerning with shocks in quasi-linear...

Assenza di nucleoside fosfondasi purinica e deficit selettivo grave dei linfociti T

Rosa Maria Corbo (1979)

Atti della Accademia Nazionale dei Lincei. Classe di Scienze Fisiche, Matematiche e Naturali. Rendiconti

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We studied a 22 months-old girl with severe selective T-cell deficiency and no measurable purine nucleoside phosphorylase activity in the RBC and granulocytes. No inhibitor was found in the patient's erythrocytes. Her parents are second cousins and their red cells exhibited about half the normal level of NP activity. The identification of heterozygotes within a three generation pedigree confirms that PNP deficiency is inherited as a mendelian autosomal trait and that erythrocytes can...

Osservazioni cariologiche su alcuni Macrobiotus (Tardigrada)

Roberto Bertolani (1972)

Atti della Accademia Nazionale dei Lincei. Classe di Scienze Fisiche, Matematiche e Naturali. Rendiconti

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The chromosome morphology and number in somatic and germinal mitoses were studied in some species of Macrobiotus. Most of these species (M. areolatus, M. coronifer, M. harmsworthi, M. hufelandii and bisexual biotype of M. richtersi) have 2n = 12 chromosomes, but in two acquatic species with similar morphology (M. dispar and M. pullari) 2n = 10 chromosomes are found. The chromosome number in males and females of M. areolatus and M. richtersi is the same. In the ripening oocytes and in...

Osservazioni sulla cinetica della transizione acido-alcalina nella metamioglobina di Aplisia

Giorgio Maria Giacometti, Alvaro Da Ros, Maurizio Brunori (1973)

Atti della Accademia Nazionale dei Lincei. Classe di Scienze Fisiche, Matematiche e Naturali. Rendiconti

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The paper reports a study on the kinetics of the transition between acid and alkaline Aplysia myoglobin. The results, obtained with the temperature-jump method, show that the observed relaxation effect corresponds to a perturbation of the equilibrium between the protonated and deprotonated forms of the protein. The pH dependence of the data and their analysis suggest that the process involves a proton-linked conformational change of the protein, in agreement with independent experiments....

Influenza di alcuni neurofarmaci sull’agamia degli Elosomatidi

Anna Stagni, M. Luisa Sini-Rubatta, Vincenza Morini (1980)

Atti della Accademia Nazionale dei Lincei. Classe di Scienze Fisiche, Matematiche e Naturali. Rendiconti

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Observations prolonged for two months show how aged Aelosoma viride specimens increase their asexual reproductive power. Treatment of this species with some neuropharmacological agents (norepinephrine, amphetamine, reserpine) demonstrate that: 1) noradrenaline excites the growth by increasing the number of segments; 2) amphetamine excites the growth but inhibits asexual reproduction; 3) reserpine is strongly toxic; 4) growth and asexual reproduction appear as two partially separated...

Malacofauna continentale del giacimento pleistocenico superiore a vertebrati della Via Flaminia (Roma)

Daniela Esu (1980)

Atti della Accademia Nazionale dei Lincei. Classe di Scienze Fisiche, Matematiche e Naturali. Rendiconti

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An Upper Pleistocene (post-“Ostian”) fossiliferous outcrop rich in lacustrine molluscan fauna has come to light near Rome (Flaminia Road). Before in the same tufaceous layer some remains of a steppe-elephant and a deer were also discovered. The molluscan fauna is formed by 8 lacustrine and 4 terrestrial species; they indicate a climate colder than present and open environment without arboreous vegetation or with rare restricted woody land.

Proprietà e possibile ruolo regolativo della N—formil—tetraidrofolato: metionil-tRNA transformilasi in Euglena gracilis

Annastella Gambini, Paolo Crosti, Paolo Tortora, Giovanni Lucchini, Renato Bianchetti (1974)

Atti della Accademia Nazionale dei Lincei. Classe di Scienze Fisiche, Matematiche e Naturali. Rendiconti

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The properties of N-formyl-tetrahydrofolate: methionyl-tRNA transformylase from Euglena gracilis were studied and compared with those of the E. coli enzyme. The Euglena enzyme, functioning in formylation of met-tRNA initiator of organellar protein synthesis, shows a partial requirement of Mg, with an optimum of 5 mM, stimulation by K, Km for N-formyl-THFA 2.5 x 10 M. These properties are different from those of the bacterial enzyme. For example the affinity for the substrate N-formyl-THFA...

Alcune osservazioni ultrastrutturistiche in Aelosoma (Annelida Oligochaeta)

Anna Stagni (1973)

Atti della Accademia Nazionale dei Lincei. Classe di Scienze Fisiche, Matematiche e Naturali. Rendiconti

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The ultrastructural aspects of some cellular types in Aelosoma have been investigated. Aelosomatidae are aquatic Oligochaetes in which the asexual reproduction isvery common, while sexual individuals are rare or, in some species, have never been observed. Asexual reproduction occurs by fission and regenerative processes precede the separation of the daughter zooid. In this work are described the ectodermal cells of the parent's body (including gland cells) and the blastematic cells of...

Analisi intracellulare delle risposte elettriche a stimoli cutanei registrate da neuroni corticali somesiesici provvisti di campi recettivi di diverso tipo

Giorgio Maria Innocenti, Tullio Manzoni (1973)

Atti della Accademia Nazionale dei Lincei. Classe di Scienze Fisiche, Matematiche e Naturali. Rendiconti

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Intracellular records were obtained from 31 neurones isolated from the first somatosensory cortical projection area of chloralose-anaesthetized cats. These neurones, which are part of a wider sample of 197 cells recorded extracellularly during the same experiments, were all tested with the electrical stimulation of peripheral receptive fields (PRF) and hence classified as somatotopic (contralateral, specific PRF) or non-somatotopic (wide and bilateral PRF). Upon PRF shocks, sequences...