Real points in the fibres of dominant maps defined overR

Letf: X → Y be a dominant map between real algebraic varieties of the same dimension. The object of this paper is the study of the map which sends every pointy ∈ Y to the number of real points inf ⁻¹ (y). We give a sufficient condition ony to ensure that the above map is locally constant iny. Moreover, we consider the subset ofY where this map is no more locally constant and we give the principal properties of this set.

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Sunto Siaf: X → Y un morfismo dominante tra varietà algebriche reali della stessa dimensione. In questo articolo si studia la mappa che associa ad ogni puntoy ∈ Y il numero di punti reali inf ⁻¹ (y); in particolare si dà una condizione sufficiente suy affinchè tale mappa sia costante in un suo intorno. Inoltre, si considera il sottoinsieme diY in cui tale mappa non è più localmente costante e si danno le principali proprietà di tale insieme.

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The work was written while both the authors were members of the G.N.S.A.G.A. of the Consiglio Nazionale delle Ricerche.     

On the divisor class groups of localizations,completions and veronesean subrings of z-graded krull domains

Summary LetR be aZ-graded, noetherian, integral domain. This paper deals mainly with the divisor class groups of localizations and completions with respect to an α-adic topology (α homogeneous) ofR. Some technical results are used to study the Veronesean subrings ofR.

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Riassunto SiaR un dominioZ-graduato, noetheriano. Questo articolo tratta principalmente il gruppo di classi di divisori di localizzazioni e completamenti rispetto ad una topologia α-adica (α omogeneo) diR. Alcuni risultati tecnici vengono applicati allo studio dei sottoanelli Veronesiani diR.

     

Boson Fields on the Circle as Generalized Wightman Fields

We define an operator-valued distribution on the circle with the expected properties (correlation functions, Hermiticity, etc.) of the logarithmic boson field in the cylinder compact picture. This is done starting from the known Krein space realization of the right and left movers on the light cone and considering its relation with the U(1)-current algebra. The relevance of this construction fortwo-dimensional conformal quantum field theory is discussed.     

Inclusiveπ° production in 360 GeVpp interactions using the european hybrid spectrometer

The intermediate and forward gamma detectors of EHS are used to reconstructπ°'s produced by 360 GeV/cpp interactions in the Rapid Cycling Bubble Chamber (RCBC). Using thepp forwardbackward symmetry, the inclusiveπ° production cross section is obtainedσ _π°=(132±11) mb. The averageπ° multiplicity is determined as a function of the charged particle multiplicity. The (1?x) dependence is given for differentp _T regions.     

Sul teorema di unicità per le equazioni del campo elettromagnetico in un plasma

Sunto Si dimostrano alcuni teoremi di unicità per le equazioni non-lineari del campo elettromagnetico in un plasma in cui si tiene conto della pressione dei corpuscoli elettrici. I teoremi sono sempre dimostrati nel caso non stazionario, anzitutto supponendo che il plasma occupi tutto lo spazio, poi vengono estesi al caso di un dominio finito con opportune ipotesi alla frontiera. Infine si ottengono teoremi di unicità nel caso in cui, per effetto di campo magnetico, la pressione diventa anisotropa. A Bruno Finzi nel suo 70^mo compleanno Lavoro eseguito nell'ambito dell'attività dei gruppi di ricerca del C. N R. Entrata in Redazione il 19 gennaio 1970.     

Direct measurement of the counterion distribution within swollen polyelectrolyte films

The depth profile of the counterion concentration within thin polyelectrolyte films was measured in situ using contrast variant specular neutron reflectivity to characterize the initial swelling stage of the film dissolution. We find substantial counterion depletion near the substrate and enrichment near the periphery of the film extending into the solution. These observations challenge our understanding of the charge distribution in polyelectrolyte films and are important for understanding film dissolution in medical and technological applications.     

The depth of molecular recognition: voltage-sensitive blockage of synthetic multifunctional pores with refined architecture

Voltage-sensitive blockage by ADP, ATP and phytate (IP6) demonstrates that active-site contraction toward the middle of newly synthesized rigid-rod beta-barrels provides a general strategy to rationally create and modulate the voltage sensitivity (and to increase the efficiency) of molecular recognition by synthetic multifunctional pores.     

Stereochemistry of cercosporin

The absolute configuration of the asymmetric carbons and the axial chirality of the natural mold metabolite cercosporin (from $\text{Cercospora sp}$.) have been established on the basis of X-ray analysis and chemical reactions. The results confirm the inherent dissymmetry of the perylenequinone ring, the twisting of which gives rise to the diastereoisomer isocercosporin. The energy barrier for the conversion of cercosporin into isocercosporin has been evaluated.