Showing papers by "University of Palermo published in 1978"
TL;DR: The discovery of a high-energy γ-ray source at α(1950) = 12h 29 min±6 min, δ(1950)= +3°±15° is reported in this paper.
Abstract: THE discovery of a high-energy γ-ray source at α(1950) = 12h 29 min±6 min, δ(1950)= +3°±15° is reported here Arguments are given for the identification with 3C273 If this identification is correct, the γ-ray luminosity of 3C273 in the energy range 50–500 MeV is 2×1046 erg s−1 for H0 = 60 km s−1 Mpc−1
154 citations
101 citations
TL;DR: In this article, rainwater samples collected in Venice over a period of about 1 year were studied along with stone samples collected from buildings and monuments, with the purpose of proving that atmospheric pollution is mainly responsible for the deterioration of monuments and buildings.
Abstract: Rainwater samples collected in Venice over a period of about 1 yr were studied along with stone samples collected from buildings and monuments. Isotopic measurements of O, S, and C were carried out on rainwater, rainwater dissolved sulfate, carbonate in stone, and sulfate present in altered limestone, with the purpose of proving that atmospheric pollution is mainly responsible for the deterioration of monuments and buildings. The results obtained lead to the conclusion that, in spite of the geographic position of the city, atmospheric sulfate in Venice is basically tied to the emission of anthropogenic SO2 and that only minor contribution can be expected from seawater spray and aerosols. The measurements carried out on stone samples clearly indicate that stonework is damaged by the interaction between limestone and S-bearing atmospheric pollutants.
39 citations
TL;DR: In this article, the authors developed two systems of data collecting provided with different controls, and analyzed the results using the Pearson ξ 2 test reflect a Poisson process of the radioactive decay events.
33 citations
TL;DR: In this article, durch Kondensation von o-Aminophenol oder -thiophenol mit Salicylaldehyd oder o-Vanillin synthetisierten Liganden H21, bilden bei der stochiometrischen Umsetzung mit Mn(II)-acetatdihydrat die 1:1-Komplexe (I).
24 citations
TL;DR: In this article, the trans and cis isomers of 5,5″ (cyclobut-1,2-ylene-diethynylene)bis 2,2′-bithiophene, together with the known α-terthienyl and 5-(but-3-en-1-ynyl)-2,2''bithienyl, have been isolated from the roots of Cardopatium corymbosum and evidence is given that the novel cyclobutane substances are not the products of a spontaneous dimerization of a bith
23 citations
TL;DR: Using a wetted wall laboratory absorber, the rate of ozone absorption in aqueous phenol solutions has been measured in the pH range 1.75-12.5 as discussed by the authors.
22 citations
22 citations
TL;DR: In this article, the electrochemical reduction of carbon monoxide to C4O2−4 squarate anion was investigated and the main feature appeared to be that strictly controlled conditions are not necessary for cyclotetramerization.
22 citations
TL;DR: In this paper, it has been shown that RSnCl 3 · pyz is a polymeric compound, where the ligand acts as bridging bis-monodentate and the tin atoms attain the coordination number six.
20 citations
TL;DR: Isomotiol (fern-8-en-3β-ol) was isolated from the leaves of Strychnos potatorum; it was not known previously as a natural product, but it has been obtained by acidic isomerization of compounds with a fern-7-ene or fern 9(11)-ene skeleton as discussed by the authors.
TL;DR: In this article, the generalized Melan theorem and bounds on various deformation parameters (such as displacements or plastic strain intensities) are derived for elastic-plastic bodies subjected to quasi-statically varying loads within a given domain.
Abstract: The paper concerns shakedown analysis of elastic-plastic bodies subjected to quasi-statically varying loads within a given domain. Using a perturbation method, a general inequality is given, from which, by simply specializing the perturbing terms, the generalized Melan theorem as well as bounds on various deformation parameters (such as displacements or plastic strain intensities) are derived. The solution of the «perturbed» shakedown problem in finite or holonimic terms permits the bound to be the most stringent and expressible in «local» terms instead of integral terms. A simple application concludes the paper.
TL;DR: Two new diterpenes have been isolated from Sideritis sicula as mentioned in this paper : sideripol, ent -18-acetoxy-7α-hydroxykaur-15-ene and epoxysideritriol.
TL;DR: Three new species of predacious mites from Italy, Typhlodromus ernesti, T. laurentii and T. pegazzani are described and illustrated.
Abstract: Three new species of predacious mites from Italy, Typhlodromus ernesti , T. laurentii and T. pegazzani are described and illustrated. T. baccettii Lombardini, 1960 is redescribed.
TL;DR: In this paper, the authors investigated addition reactions of 1,2-dimethylpyrrole and 1-methyl-2-carbomethoxypyrrole with C-acetyl-N-phenylnitrilimine.
TL;DR: In this paper, the authors generalize this result to rings with involution and show that if R is a primitive ring with a center % satisfying a positive integer depending on s and y, then dim,R < 4.
TL;DR: In this article, the role of pulsars as identified γ-ray sources could be simply related to observational reasons: in fact, because of the poor angular resolution intrinsic to the γray telescopes, the only possibility of identification for individual sources is the time structure of the emission.
Abstract: PULSARS seem to play a major role as γ-ray emitters Of the 13 objects listed in the first COS B catalogue1 the two brightest, CG185-5 and CG263-2, have been identified with the Crab (PSR0531+21) and Vela (PSR0833–;45) pulsars respectively This privileged role of pulsars as identified γ-ray sources could be simply related to observational reasons: in fact, because of the poor angular resolution intrinsic to the γ-ray telescopes, the only possibility of identification for individual sources is the time structure of the emission, and the periodical pattern of pulsars is particularly suited On the other hand, for PSR0531+21 and PSR0833−45, the observed pulsed energy release is essentially in the γ-ray channel, with a ratio between the γ and radio luminosity as high as ∼106
TL;DR: The high-dose behaviour of CaSO4: Dy TL dosimeters observed by some authors is compared with the one deduced by the continuous distribution of trap depths previously proposed by as discussed by the authors.
TL;DR: Two new species of predacious mites of the family Phytoseiidae are recorded from various plants in Kenya, including the new species and the male of A. natalensis.
17 Jul 1978
TL;DR: In this paper, the molecular dynamics of chains partly attached to the crystal and partly immersed in the solution are considered, and the influence of temperature and of geometrical factors is also discussed.
Abstract: The recent experimental results on flow-induced crystallization by Pennings and coworkers show that extremely rigid polyethylene fibers can be obtained in a shear flow. On the other hand, the mechanism by which these flow-induced crystals are produced is still open to investigation. In this work a few aspects of fibrous crystal growth are theoretically investigated. The molecular dynamics of chains partly attached to the crystal and partly immersed in the solution is considered. The influence of temperature and of geometrical factors is also discussed.
TL;DR: SDS-polyacrylamide gel electrophoresis of plasma membrane proteins from sea urchin embryos at the swimming blastula stage allows the identification of fifteen-seventeen components, five of which are glycoproteins, one of which is almost completely absent in the plasma membrane of trypsin treated cells.
TL;DR: In this article, cylindrical specimens of L.D. polyethylene were brought to various temperatures above the melting point and rapidly drawn to form filaments, and a linear stability analysis was performed in the classical way by first reducing the system equations to an equivalent set which admits a steady-state solution.
Abstract: Cylindrical specimens of L.D. polyethylene were brought to various temperatures above the melting point and rapidly drawn to form filaments. Depending on temperature and stretching rate, surface instabilities were observed. A linear stability analysis was performed in the classical way by first reducing the system equations to an equivalent set which admits a steady-state solution. Both Newtonian and Maxwellian fluids were considered.
TL;DR: A latent infection by measles virus in a line of Vero cells could be maintained only at 37° C, associated with some block in virus production and/or release and with the establishment of an autointerference phenomenon.
Abstract: A latent infection by measles virus in a line of Vero cells could be maintained only at 37° C. The conditions of temperature nonpermissiveness were associated with some block in virus production and/or release and with the establishment of an autointerference phenomenon. Reduction of the incubation temperature to 33.5° C induced a rather rapid transition from the latent to a lytical infection with a rescue of virus. The rescued virus exhibited a restricted capacity to grow at 37° C.
TL;DR: A hazard-free multiple-output Walsh function generator is presented which requires a minimum amount of hardware and is as fast as the integrated logic family employed for the implementation.
Abstract: A hazard-free multiple-output Walsh function generator is presented which requires a minimum amount of hardware and is as fast as the integrated logic family employed for the implementation. However, the main characteristic of the instrument is the optimum performance from the viewpoint of the orthogonality of the function generated, as it is shown by the experimental verifications reported.
TL;DR: In this article, a new synthesis of pyrrolo[3,2-b] pyridine starting with pyrrole ring was described, which allowed the synthesis of 4-azaindoles bearing a sensitive group at C-7.
TL;DR: In this article, the addition reaction of C-acetyl-N-phenylnitrilimine to pyrrole has been investigated, and the products obtained show that the reaction proceeds via two distinct pathways.
TL;DR: In this article, the authors discuss the role of zone ABSORPTION KINETICS in AQUEOUS PHENOL SOLUTIONS, and discuss the relationship between ozone depletion and ozone depletion.
Abstract: (1978). TEMPERATURE DEPENDENCE OF THE OZONE ABSORPTION KINETICS IN AQUEOUS PHENOL SOLUTIONS. Chemical Engineering Communications: Vol. 2, No. 4-5, pp. 219-221.