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31.
32.
Pasquale Calapso 《Annali di Matematica Pura ed Applicata》1929,7(1):225-229
Sunto. In questa Memoria vengono formati gl'inviluppi di sfere, sulle cui focali si corrispondono le linee di curvatura e le linee
asintotiche, con la considerazione della congruenzaaggiunta; il problema è ridotto ad un sistema diCauchy e la soluzione generale dipende da quattro funzioni arbitrarie di una sola variabile. 相似文献
33.
34.
Pasquale Calapso 《Annali di Matematica Pura ed Applicata》1929,7(1):213-224
Sunto. In questa Memoria è stabilita una trasformazione di una data congruenza ciclica(G) in una nuova congruenza ciclica (G
1), attraverso un sistema di cinque sfere a due a due ortogonali. L'equazione diLaplace per i parametri direttori della rettaG
1 èl'aggiunta di quella relativa a(G). La (G
1) è generale se tale è la(G). 相似文献
35.
Pasquale Calapso 《Annali di Matematica Pura ed Applicata》1930,8(1):201-213
Sunto Nel presente lavoro è stabilita una trasformazione delle congruenzeW, secondo la quale il problema della determinazione di tali congruenze è ridotto alla formazione di una reteO dello spazio a quattro dimensioni, e di due altre tali reti equivalenti adO per trasformazioni conformi. Il caso in cui sulle superficie focali della congruenza si corrispondono le linee di curvatura,
è caratterizzato da una relazione fra le curvature isotrope delle retiO, da cui dipende il problema. 相似文献
36.
37.
Pasquale Ferranti Serena Fabbrocino Antonella Nasi Simonetta Caira Milena Bruno Luigi Serpe Pasquale Gallo 《Rapid communications in mass spectrometry : RCM》2009,23(9):1328-1336
Cyanobacteria, also called blue‐green algae, occur worldwide within water blooms in eutrophic lakes and drinking water reservoirs, producing several biotoxins (cyanotoxins). Among these, microcystins (MCs) are a group of cyclic heptapeptides showing potent hepatotoxicity and activity as tumour promoters. So far, at least 89 MCs from different cyanobacteria genera have been characterised. Herein, ion trap, matrix‐assisted laser desorption/ionisation time‐of‐flight (MALDI‐ToF) and quadruple time‐of‐flight (Q‐ToF) mass spectrometry (MS)‐based methods were tested and compared for analysing MCs in freshwaters. Method performances in terms of limit of detection, limit of quantification, mean recoveries, repeatability, and specificity were evaluated. In particular, a liquid chromatography/electrospray ionisation (LC/ESI)‐Q‐ToF‐MS/MS method was firstly described to analyse MCs in freshwaters; this technique is highly selective and sensitive, and allowed us to characterise the molecular structure of an unknown compound. Indeed, the full structural characterisation of a novel microcystin variant from a bloom of Planktothrix rubescens in the Lake Averno, near Naples, was attained by the study of the fragmentation pattern. The new cyanotoxin was identified as the 9‐acetyl‐Adda variant of microcystin‐RR. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
38.
Elisabetta Tornatore Stefania Maria Buccellato Pasquale Vetro 《Rendiconti del Circolo Matematico di Palermo》2006,55(2):223-240
We propose a stochastic disease model where vaccination is included and such that the immunity isn’t permanent. The existence,
uniqueness and positivity of the solution and the stability of disease free equilibrium is studied. The numerical simulation
is done. 相似文献
39.
We consider the time evolution of observables in the transverse-field Ising chain after a sudden quench of the magnetic field. We provide exact analytical results for the asymptotic time and distance dependence of one- and two-point correlation functions of the order parameter. We employ two complementary approaches based on asymptotic evaluations of determinants and form-factor sums. We prove that the stationary value of the two-point correlation function is not thermal, but can be described by a generalized Gibbs ensemble (GGE). The approach to the stationary state can also be understood in terms of a GGE. We present a conjecture on how these results generalize to particular quenches in other integrable models. 相似文献
40.
In this paper we model concession contracts between a public and a private party, under dynamic uncertainty arising both from the volatility of the cash flow generated by the project and by the strategic behaviour of the two parties. Under these conditions we derive three notions of equilibrium price and apply the model to a case study for one of the most important concession contracts in Italy. 相似文献