Showing papers by "National Nuclear Energy Commission published in 1975"
TL;DR: In this paper, a detailed expression for radiative corrections to colliding beam experiments in the presence of resonances, including interference effects, is presented, using perturbation theory methods as well as coherent state formalism.
76 citations
TL;DR: In this paper, new expressions for radiative corrections to colliding beam experiments in presence of narrow resonances, including interference effects, were presented for ψ(3.1) and ψ (3.7) to obtain the values ( Γ e Γ h / Γ )=(4.0±0.2) and (2.8 ± 0.3)
30 citations
TL;DR: In this article, the authors compared the results corresponding to a semi-crystallic structure characterized by correlated density fluctuations of the four spin-isospin nucleon types, with those corresponding to the standard Fermi gas homogeneous and isotropic nuclear-matter structure.
Abstract: Variational computations of the binding energy per particle for various models of nuclear matter are reported The main purpose is to compare the results corresponding to a «semi-crystallic» structure characterized by correlated density fluctuations of the four spin-isospin nucleon types, with those corresponding to the standard «Fermi gas» homogeneous and isotropic nuclear-matter structure It is found that, in some cases, the semicrystallic configuration yields more overall attraction (actually less overall repulsion) than the Fermi-gas case, already at (mean) nuclear densities equal to the central density of ordinary (heavy) nuclei This effect becomes more pronounced at higher (mean) nuclear densities; it can, in most cases, be attributed, at least in part, to the tensor component of the nuclear interaction, that averages to zero in the Fermi-gas case, and yields instead an attractive contribution in configurations with appropriately correlated density fluctuations of the four spin-isospin nucleon states All computations are based on realistic one-boson exchange nucleon-nucleon potentials The correlations associated with the strongly repulsive character of the nucleon-nucleon interaction at short range have not been properly accounted for The results of this paper have therefore no immediate phenomenological implications; whether the effect displayed here is preserved when the repulsive core of the nucleon-nucleon interaction is properly taken into account (both in the computations with and without density fluctuations) remains an open question
26 citations
TL;DR: The self-shunted streamer chambers can be used as visualizers of particle tracks and as detectors of event vertices, and the results in the precision which can be obtained in the reconstruction of the tracks are discussed in this article.
20 citations
TL;DR: Electron microscopy analyses of self-incompatible hybrids indicate that a single gametophytic factor governs interspecific incompatibility in hybrid pollen and is allelic or linked to the S locus.
Abstract: Fragments in certain pollen-part mutants are suspected to originate from duplications of satellited regions. Linkage tests demonstrate that, if this interpretation is correct, either the specificity segment of the S locus is not on the fragment or two unliked specificity segments operate respectively in pollen and style. As electron microscopy and the effects of giberellic acid on selfing suggest that one manifestation of incompatibility reactions is a cessation of protein synthesis in pollen tubes, it is possible that the fragment does not carry an S locus but ribosomal cistrons necessary for the maintenance of activity. Ancestry tests are under way for testing the hypothesis that different specificity segments are organized as tandem repeats and can be switched on and off in inbred backgrounds. Electron microscopy analyses of self- incompatible hybrids indicate that a single gametophytic factor governs interspecific incompatibility in hybrid pollen and is allelic or linked to the S locus.
16 citations
12 citations
TL;DR: In this paper, the maximum Josephson current with temperature for Nb−NbOx−Pb junctions was found to differ from the BCS Ambegaokar−Baratoff curve.
Abstract: Measurements of the maximum Josephson current with temperature for Nb−NbOx−Pb junctions differ from the BCS Ambegaokar−Baratoff curve. This cannot be explained in terms of strong coupling effects. A possible explanation might be proximity effect of a normal layer on the niobium surface.
12 citations
TL;DR: In this article, the magnetic field dependence of light-induced Josephson current is reported. And the junction behavior has been observed on the same sample for different light induced current levels.
11 citations
11 citations
TL;DR: Polyribosome inactivation occurs due to the damage at the 3′OH terminal of the translated mRNA sequence, thus confirming that the availability of messenger molecules directing hemoglobin synthesis is the only factor controlling the extent of hemoglobin gene expression during the terminal differentiation of an erythroid clone.
Abstract: Publisher Summary Sequential differentiative events have three main stages in the differentiation of mammalian erythroid cells: (1) transition from stem cells, (2) committed cells are induced to express the genes for the specialized proteins and become irreversibly committed cells, and (3) terminal differentiation This chapter discusses the data relative to the differentiation of erythroid cells derived from the yolks sac (YSEC) of fetal mice and describes the basic biochemical aspects of YSEC terminal differentiation Proteins not directly endowed with the specialized differentiated function, but related to the maintenance of cellular activities, are produced during the early stages of maturation and their synthesis shows an immediate temporal dependence on transcriptional events The synthesis of specialized proteins, such as hemoglobin, is not dependent on the transcriptional events within a short time interval During the terminal stages of erythroid differentiation, a continuous decrease of polyribosome content per cell and the reduced availability of mRNAs active for hemoglobin synthesis are observed The arrest of hemoglobin production is accompanied by the formation of polyribosomes that maintain the aggregated structure but are inactive in protein synthesis Inactive polyribosomes may not be reactivated in vitro by the addition of any of the factors necessary for protein synthesis Polyribosome inactivation occurs due to the damage at the 3′OH terminal of the translated mRNA sequence, thus confirming that the availability of messenger molecules directing hemoglobin synthesis is the only factor controlling the extent of hemoglobin gene expression during the terminal differentiation of an erythroid clone
11 citations
TL;DR: A search for narrow resonances in the reaction e + e − → hadrons in the mass regions 1915-2345 MeV and 2970-3090 MeV has been perforned at ADONE, the Frascati storage ring.
TL;DR: In this article, a numerical method is presented for solving the MHD equilibrium equation for free-boundary plasmas in axially symmetric toroidal configurations, with an arbitrary cross-section of the external conducting casing.
Abstract: A numerical method is presented for solving the MHD equilibrium equation for free-boundary plasmas in axially symmetric toroidal configurations, with an arbitrary cross-section of the external conducting casing. Magnetic fields produced by currents in axially symmetric external conductors are taken into account. It is shown that the method can also be applied when a limiter is present in the plasma chamber.
TL;DR: In this paper, the asymptotic behaviour of the form factor for non-relativistic bound systems is derived for local and non-local two-and three-body potentials, taking into account the Pauli principle.
TL;DR: In this paper, the heat transfer coefficient between fuel and cladding has been measured in-pile for different types of Zircaloy-2 sheathed fuels: UO2 and UO 2-PuO2 pellets, Vipac, and Sphere-Pac sol-...
Abstract: The heat transfer coefficient between fuel and cladding has been measured in-pile for different types of Zircaloy-2 sheathed fuels: UO2 and UO2-PuO2 pellets, UO2 Vipac, and UO2-PuO2 Sphere-Pac sol-...
TL;DR: In this paper, the authors show that the canonical trace anomaly of the energy-momentum tensor can be related to the low-energy behavior of a(e+e - -~hadrons) through a general duality principle which they derive explicitly.
Abstract: One of the most puzzling results of deep inelastic experimentation in the last few years is the large cross-section of e+e- annihilation into hadrons (~). The almost constant cross-section observed is in marked disagreement with the pointlike behaviour expected theoretically on the basis of scaling. The question thus arises as to whether there is complete break-down of scaling or it is postponed to much higher energies. Adopting this latter point of view, we show in this letter how in the framework of the canonical trace anomaly of the energy-momentum tensor the asymptotic value of the ratio R = a(e+e--~hadrons)/~(e+e-->~+~-) can be related to the low-energy behaviour of a(e+e - -~hadrons) through a general duality principle which we derive explicitly. Some time ago we proposed (~) a simple model in which sealing is built up by a series of resonances of Veneziano type in which this duality principle between /~ and low-energy parameters is verified. Explicitly we found i~ = 8n~//~ ~ 2.5. A similar treatment by SAKURAI (a) gives numbers between 3 and 5, but, as we shall show later, a more accurate analysis will confirm the value of :R given above. Recently from a completely different point of view T]~RAZAW~ (~) has determined the anomaly of PCDC (partial conservation of dilatation current) Ward identity using conventional vector-meson dominance of real photons and found for R a value of 16~/]~. (t) B. ]3ARTOLI, F. FELICETTI, H. OGREI~ r, V. SILVESTRINI, G. MARI~I, fi_. IGRO and F.VAI~OLI: Phys. Rev. D, 6, 2374 (1972); C. B~-ooI, G. I~ G. SALVI~I, B. STELLA, m. BALDI~I CELIO, G. CAPOI~, C. ]~ENOUOOINI, G. P. MURTAS, M. SPn~ETTI and A. ZALLO: Phys. Le~., 44 B, 533 (1973); F. CERADINI, M. CO~VERSI, S. D'A~GELO, L. PAOLUZI, R. S.
TL;DR: In this paper, two different fixed targets have been designed: a high average power target used to produce a high duty cycle (4 μs, 250 pps) positron beam for nuclear physics experiments, and a high positron production efficiency, low average-power target, used for injection of positrons into the storage ring, Adone, when a beam repetition rate of only 3 pps is allowed, but is required, to reduce the ring filling time.
TL;DR: Data interpreted as the evidence for a block of chain termination producing inactivation of polyribosomes during the late maturation of nucleated erythroid cells are interpreted.
TL;DR: In this paper, the authors presented a counter system designed to measure the luminosity of Adone, the Frascati e+e− storage ring, by detecting electron-positron pairs scattered at small forward angles.
TL;DR: A series of nine atmospheric diffusion experiments was carried out, using a uranine dye aerosol as a tracer during unstable conditions, generally characterized by the presence of a sea-breeze, and therefore in a well defined wind direction as mentioned in this paper.
TL;DR: In this article, the Lagrangian point of view was compared with the Eulerian view to predict the onset of the transient CHF for the Centro Informazioni Studi Esperienze annuli experimental data and General Electric Company 16-rod bundles data under typical boiling water reactor transients.
Abstract: The calculations performed in comparison of the ''Lagrangian point of view'', by means of the DOLCE computer code with the local space--time approach of the ''Eulerian point of view'' indicate that the two methods give substantially equivalent results and predict satisfactorily the onset of the transient CHF for the Centro Informazioni Studi Esperienze annuli experimental data and General Electric Company 16-rod bundles data under typical boiling water reactor transients, including loss-of-coolant accident simulations. 9 references. (auth)
TL;DR: In this article, the authors described the production of monodisperse aerosols in the ultrafine range, based on the general condensation scheme, where the boiler is suppressed, as the material is fed directly to the reheater in the form of argon-borne particles.
TL;DR: In this article, a method for computing eigenvalues and eigenvectors of the Schrodinger equation is presented, which consists in a numerical approximation to the path integral combined with the moment method.
Abstract: A method for computing eigenvalues and eigenvectors of the Schrodinger equation is presented. The method consists in a numerical approximation to the path integral combined with the moment method. An estimate of the error and a discussion of the choice of the parameters is given.S-wave eigenvalues are computed for some typical two-body problems.
TL;DR: In this paper, a negative-metric boson of the Lee-Wick type was employed to partially understand the destructive interference before the resonance in the e+e− data.
Abstract: As discussed previously, taking the dip which is seen in the e+e− data about 1 MeV below the peak at its face value, one is led to demand a large total width which however cannot now be attributed to known leptonic channels. The problem of the destructive interference before the resonance can be partially understood provided one employs a negative-metric boson of the Lee-Wick type. Also, the charge asymmetry in μ+μ- channel as observed requires one to relax the pureV-A structure and thus give up chirality. Lastly, the possibility of spin other than 1 is still open. We hope to return to these problems elsewhere.
TL;DR: In this article, the authors compared the threshold behavior of pion production with the SPEAR data and derived F T ( π +) (x ) ≈ F L ( ρ +)(x ) ⪢ F L( π 0) ( x ) for x near 1.