On the interaction of small molecules with hemoproteins: Sperm whale myoglobin

The spin label TEMPO does not show a binding to myoglobin molecule in solution. This is probably due to the fact that this protein does not have a hydrophobic pocket large enough to accommodate the TEMPO molecule. In the crystal the spin label is bound and two kinds of spectra are observed: one isotropic and the other anisotropic. The anisotropic site is probably an intermolecular one. The correlation time for the label in the crystal is very sensitive to temperature showing a transition near 30 °C. This change can be explained as a result of the conformational change observed for myoglobin near this temperature: the motion of the spin label becomes more restricted below this temperature. Change in hydration is the probable cause of this structural change. The changes in the EPR spectra of the anisotropic label suggest that it is bound near the first layers of protein in the crystal. © 1985 Societá Italiana di Fisica.

Hadronic spectroscopy: Light and heavy mesons

We calculate the spectrum of the masses of light and heavy mesons, using a potential that shows confinement and asymptotic freedom for quark-antiquark pairs. From the analysis of the results we estimate the masses of mesons with hottom not yet found experimentally. We discuss the behaviour of the confinement potential under Lorentz transformation and calculate the spin-dependent corrections. We also calculate the electromagnetic decay rates and the leptonic and hadronic decay widths for some mesons. © 1985 Società Italiana di Fisica.

A potential approach for the gluonium spectrum

A potential previously utilized in the quark sector is extended to the gluon one. The short-range gluon-gluon interaction potential using QCD is calculated. To simulate the confinement a confining potential and an effective mass for the gluon are introduced. © 1989 Società Italiana di Fisica.

Atmospheric cosmic rays in the South Atlantic anomaly region

To study the production and propagation of fast secondaries particles in the atmosphere, data collected during eleven quiet-time balloon flights are analysed. Comparisons of these data with those obtained in different geomagnetic rigidity regions permit to estimate the contributions of the proton and electron components in the measured intensities. Derivations of this last component in the «upward» and «downward» moving electrons fluxes indicate that in the anomaly region a fraction of these particles, produced by the primary protons, are leaving the atmosphere and will not return to the Earth. © 1991 Società Italiana di Fisica.

Short-period variation of cosmic-ray intensity and ozone density observed in the stratosphere

The energy deposition by slowing-down of energetic ionizing particles in the atmosphere enhances the production of constituent concentration which perturbs and eventually destroys the ozone (OZ) layer. Near the Brazilian anomaly region the cosmic-ray (CR) intensity varies greatly due to the magnetic activity in that region. In order to study these variations, stratospheric balloons were launched to measure, simultaneously, the CR and OZ fluxes in the atmosphere. The Fourier-analysed data collected during the flight on April 22, 1989 show evidences of a short-period variation for both fluxes measured. Attempts to verify the physical mechanisms which associate the CR change with the OZ one are not conclusive due to limited data observed on that event. © 1993 Società Italiana di Fisica.

Secondary protons in the atmosphere at different latitudes

We present a semiempirical method to study the production and propagation of atmospheric secondary protons with energy>100 Mev, moving in the vertical direction. The derived production functions are fitted by the least-square method for the only previously published splash (SP) and return (RE) albedos observed data using the same instrument and measurement sites. The closed agreements between the measurement data and the calculations over a wide range of atmospheric depths lead to a possible extension of the method for other latitudes. The spectra of SP and RE intensities versus the geomagnetic cut-off reveal similar behaviour as assumed earlier by the theory for those components in the Earth's magnetic field. © 1993 Società Italiana di Fisica.

Schwinger's principle and gauge fixing in the free electromagnetic field

A manifestly covariant treatment of the free quantum eletromagnetic field, in a linear covariant gauge, is implemented employing Schwinger's variational principle and the B-field formalism. It is also discussed the Abelian Proca model as an example of a system without constraints. © Società Italiana di Fisica.

Estudo morfológico e histomorfométrico sobre variações sazonais do ducto deferente de codorna da variedade italiana

In the autumn the vas deferens of the Italian variety of domestic quail appeared as a single, thin, and straight duct along its total extension. Thus, transversal histologic sections of this duct showed a circular tubular shape. The pseudoestratified columnar epithelium that lined the vas deferens presented longitudinal folds which invaded the lumen frequently empty of spermatozoa. Although in the winter, spring and summer the usual morphological appearance of the quail's vas deferens was seen as a highly coiling duct. So, each transversal histologic section of the vas deferens, in all the segments, showed parallel cut sections of the duct being irregular in shape and variable in number and interconnected by the adventitial loose connective tissue. In these observations, the tubular lumen was totally performed by spermatozoa and seminal fluid. Consequently, with previous base on the testis kinetics of the Italian quail variety, it was concluded that the spermatozoa production, followed by emission, storage and ejaculation of spermatozoa through the vas deferens did not stop during the winter, spring and summer, but ceased in the autumn the quiescent phase of the circannual reproductive cycle in this bird.

Vieillissement et développement au sein d'une societé pour tous les âges

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La reestructuración industrial en la perspectiva italiana

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La pequeña y mediana industria (PMI) en la industrialización italiana: reestructuración y transformación en los ochenta

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Especialización y competitividad de la industria italiana en el comercio internacional

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Inmigración italiana a la Argentina, Brasil y Uruguay: bibliografía selectiva

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La inmigración española, italiana y portuguesa: Chile 1860-1930

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Braneworlds scenarios in a gravity model with higher order spatial three-curvature terms

In this work we study a Hořava-like 5-dimensional model in the context of braneworld theory. The equations of motion of such model are obtained and, within the realm of warped geometry, we show that the model is consistent if and only if λ takes its relativistic value 1. Furthermore, we show that the elimination of problematic terms involving the warp factor second order derivatives are eliminated by imposing detailed balance condition in the bulk. Afterwards, Israel's junction conditions are computed, allowing the attainment of an effective Lagrangian in the visible brane. In particular, we show that the resultant effective Lagrangian in the brane corresponds to a (3 + 1)-dimensional Hořava-like model with an emergent positive cosmological constant but without detailed balance condition. Now, restoration of detailed balance condition, at this time imposed over the brane, plays an interesting role by fitting accordingly the sign of the arbitrary constant β, insuring a positive brane tension and a real energy for the graviton within its dispersion relation. Also, the brane consistency equations are obtained and, as a result, the model admits positive brane tensions in the compactification scheme if, and only if, β is negative and the detailed balance condition is imposed. © 2013 Springer-Verlag Berlin Heidelberg and Società Italiana di Fisica.