Search

IntroduzioneUn mutamento di regime influisce su milioni di persone, suscitando una serie di emozioni che vanno dal timore alla speranza. La Marcia su Roma, il Machtergreifungdi Hitler, la guerra civile spagnola, i colpi di stato di Praga nel 1948 e quello contro Allende, questi drammi, che sono il simbolo di un trasferimento di potere, si fissano nella mente del popolo come date fondamentali nella sua storia. Ciò nonostante, l'avvenimento in sé è solo l'apice di un processo di mutamento politico graduale, lungo un periodo di tempo piú o meno prolungato. è possibile che gli scienziati sociali scoprano un modello comune in questi processi che conducono a mutamenti di regime, o ci troviamo di fronte a situazioni storiche irripetibili? è possibile costruire un modello almeno descrittivo del processo del crollo della democrazia che possa infine contribuire ad una migliore comprensione dei suoi elementi e della sua dinamica? Se fosse possibile costruire un tale modello, che idealmente è un modello esplicativo, ne sapremmo di piú sulle condizioni richieste per la stabilità della democrazia. Certamente, il problema della stabilità e del rovesciamento dei sistemi politici ha avuto un ruolo rilevante nella mente umana dal momento in cui l'uomo cominciò a trattare di politica.

Ultraviolet irradiation (351, 364 nm) of the n-type semiconductor TiO2as the single crystal electrode of an aqueous electrochemical cell evolves O2at the TiO2electrode and H2at the Pt electrode. The gases are typically evolved in a two: one (H2:O2) volume ratio. The photoassisted reaction seems to require applied voltages, but values as low as 0.25 V do allow the photoassisted electrolysis to proceed. Prolonged irradiation in either acid or base evolves the gaseous products in amounts which clearly demonstrate that the reaction is catalytic with respect to the TiO2. The wavelength response of the TiO2and the correlation of product yield and current are reported. The results support the claim that TiO2is a true photoassistance agent for the electrolysis of water. Minimum optical storage efficiencies of the order of 1% can be achieved by the production of H2.

The approach given in this paper leads to numerical methods for Volterra integral equations which avoid the need for special starting procedures. Formulae for a typical fourth-order method are derived and some numerical examples presented. A convergence theorem is given for the method described.

Infinite integrals involving Bessel functions are recast, by means of an Abel transform, in terms of Fourier integrals. As there are many efficient numerical methods for computing Fourier integrals, this leads to a convenient way of approximating Bessel function integrals.

Adolescent boys, 13 to 14 years old, were subjected to identical dietary treatments with each being of 2 successive years. Treatments each lasting 15 days were: low protein, low magnesium (LPLM); low protein, high magnesium (LPHM); high protein, low magnesium (HPLM); and high protein, high magnesium (HPHM).Magnesium retentions were significantly increased by consumption of the high protein diet. This was due to decreased fecal losses without concomitant changes in urinary excretion. Regression lines of magnesium retention on intake intercepted the X axis at 7.6 mg Mg/kg when subjects were fed the low protein diet and at 4.6 mg/kg with the high protein diet. The implications of these findings for formulation of requirements are discussed.

The well-known error estimates for the numerical computation of eigenvalues of symmetric integral equations are extended to the computation of the eigenvectors. The results are used to justify the application of an improvement method to obtain an efficient algorithm for solving the eigenvalue problem.

For various stated reasons, the parties that are neither religious nor class- or function-based have escaped scholarly attention. These laic-bourgeois parties have been important in themselves and in the meaning that their failure may hold for European democracy. The growing religious split in Euro pean parties also needs study.

Measurements have been made of the phonon dispersion relation for the transverse optic and acoustic branches of lowest energy in cubic KTN (KTa0.63Nb0.37O3). As in KNbO3 and BaTiO3 one optic branch is soft and overdarnped for all wavevectors q in 〈100〉 directions. The dispersion relation for this branch Js very anisotropic, the energy increasing rapidly with increasing q in 〈110〉 directions for polarization e parallel to 〈110〉 directions. The eigenvectors have been determined at |q| =0.2 a* by measuring the neutron scattering cross section in various Brillouin zones for both the TO and TA branches. The pattern of atomic displacement in the soft mode is found to be primarily of the "Slater" (g1) and "Last" (22) types and does not contain in g3 component. In this respect it resembles the corresponding modes in KTaO3 and SrTiO3 more closely than those in KNbO3 and BaTiO3. At||q|| =0.2 a* the relative atomic displacements in the soft mode are ζK = 3ζTa_Nb,) ζor = ζon = ζom = -2ζTa-Nb The mode contains an acoustic (g0) component which is due, at least in part, to an interaction between the optic and acoustic branches.

Nine adolescent boys were fed three levels of dietary nitrogen between 0.08 and 0.12 g/kilogram body weight. Caloric intakes were 55 to 59 kcal/kg. One year later eight of the original boys were fed the same diets except that caloric intakes were adjusted to current body weights. The mean increase in weight over the 1-year period was 4.6 kg; in height, 4 cm; in lean body mass, 4%; and in surface area, 0.08 m2. The daily nitrogen retention necessary to support a weight gain of 4.6 kg was 0.36 g. For dietary protein of Biological Value 100 the minimum protein requirement of these adolescent boys was 26.9 to 29.7 g/day. The calorie conversion factor for protein in the diets fed was 3.46, and apparent digestibility of the protein was 79 to 85%. The percentage of dietary energy excreted in urine was 1 and 2%, when the lowest and highest levels of nitrogen, respectively, were fed; fecal calories were the same, 4%, when the two levels were fed. Total dietary sulfur increased as dietary nitrogen increased; however, urinary total sulfur decreased at the higher sulfur intake while total sulfur in feces was unchanged.

A method useful in the numerical computation of integrals involving Bessel functions is extended to the case where the integrand contains products of trigonometric and Bessel functions.