Showing papers by "National Nuclear Energy Commission published in 1971"

Manifestly conformal covariant operator-product expansion.

Abstract: :ks is well known, scale invar iance (t) in conjunc t ion wi th Wilson 's opera to r p roduc t expans ion (2) appears to p lay an essent ia l role in t he se t t ing-up of a theore t ica l f r ame for the i n t e rp re t a t i on of expe r imen t s , such as deep inelast ic lep ton sca t te r ing , which in configurat ion space depend on the behav iour near t h e l ight-cone. I t has been sugges ted t h a t the s t ronger conformal invar iance may indeed apply in such l imit ing condi t ions and i ts impl ica t ions for equ~d-time c o m m u t a i o r s (3) and for ope ra to r p roduc t expans ions (4-e) have been discussed. In par t icu lar , in ref. (5.6) t he implicati()ns of conformal covar ianec on the opera to r p roduc t expans ion on the l ight-cone (2,7) have been fully der ived , by a m e t h o d using the Jacob i ident i t ies in ref. (4.5), and by an a l t e rna t ive mani fcs t ly covar ian t m e t h o d in ref. (s). The la t t e r m e t h o d takes advan t age of the i somorph i sm be tween the conformal a lgebra and the o r thogona l algebra O4.. , (s) aud makes use of a s ix-d imens ional pseudo-Eucl idcan co-ord ina te space. ]n th is note we shall f u r t he r develop such m e t h o d to der ive a mani fes t ly conformal covar ian t opera to r -produc t expans ion valid at all values of x 2. We n m s t s t ress t ha t , whereas conformal inva r iance (as well as scale invar iance) of the comple te t heo ry m a y in fact unde r some form hold near t he l ight-cone, wc mus t exclude the possibi l i ty t h a t the complc tc t heo ry

Plantes Haploides et Lignes Isogeniques de Nicotiana Tabacum Obtenues par Cultures D'Antheres et de Tiges in Vitro

Abstract: SUMMARYThe in vitro production of tobacco haploid plants by anther culture (NITSCH'S medium) was applied to various tobacco cultivars of great agronomic interest.The origin of the embryoids appears to be mostly due to the division of the vegetative nucleus of the male gametophyte but one albina plantet was obtained indicating that the generative nucleus can occasionally give a haploid plant.The cytophotometric measurements of the DNA content of the pith nuclei in the haploid plants, compared with the chromosome numbers of the plants regenerated from haploid stem calluses, shows that haploid cells are generally responsible for plant regeneration (ca. 50 to 60%), but also diploid and, in exceptional cases, tetraploid cells can regenerate a plant.The in vitro culture of stem disk coming from haploid plant thus offers the possibility of i) multiplying the haploids and ii) obtaining, at same time, plants isogenic at the diploid and tetraploid levels.

Muon energy losses and range straggling in the 10 <E < 105 GeV region

Abstract: The energy loss rate of underrock muons of energy between 10 and 105 GeV is calculated using recent experimental information on the nuclear interactions and recent calculations on pair production and bremsstrahlung. The effect of the range straggling is evaluated with an accurate Monte Carlo calculation and the intensity-depth curve at great depths is derived for different values of the index of the muon energy spectrum at sea level in the TeV region.

Exhalative supergenic uranium, thorium and marcasite occurrences in quaternary volcanites of central Italy

Abstract: In the Quaternary alkali-potassic volcanites of Northern Latium, there are classical solfataras related to volcanic structures, and very large kaolinized fields, at the borders of the volcanic systems (perivolcanic), related to pre-volcanic tectonic structures. In the solfataric type of mineralization thorium and sulphur ores in an opaline matrix are prevailing; in the perivolcanic type of deposit are prevailing uranium ores in very regular layers associated with kaolin. Marcasite-pyrite beds and lenses are common in both of them. The mineralization processes start with the oxidation of H2S coming out from volcanic edilices or from large faults. The origin of U and Th concentrations is to be seen in the anomalous high content of radioactive elements in the alkaline rocks, and in their enrichment in ground waters. The perivolcanic uranium mineralizations are of some economic interest: the ore deposition is controlled by ground water level in reducing conditions determined by H2S, not unlike to the principal sedimentary uranium ores known in the continental environment.

Multiple e.m. processes in high-energy e−e± collisions

Abstract: The production of electron and muon pairs is studied in high-energy e−e± collisions. Total and differential cross-sections are discussed with special regard to experimental implications. Hadron production via photon-photon scattering is also studied, and suggestions are made for present and near future experiments.

Investigation of the reaction35Cl(n, γ)36Cl

Abstract: The γ-radiation emitted following neutron capture in natural chlorine was studied. About 170 transitions were observed. A neutron separation energy of (8581.5±0.2) keV was found for36Cl. By applying the Ritz combination principle it was possible to construct a level scheme involving 17 excited states in36Cl. The multipolarity of the transitions of highest intensity was identified: fiveM1 +E2 transitions (8580.8, 7791.8, 7415.6, 6979.8, 6628.9 keV) and sevenE1 transitions (6620.9, 6113.0, 5716.9, 4946.4, 4617.0, 4441.8, 4083.6 keV) were found. A straightforward calculation of the average radiative strength functions allows us to conclude that in36ClM1 transitions are weaker than estimated by schematic studies of heavier nuclei.