Energy determination of electromagnetic cascades recorded in nuclear emulsions

1968 ◽  
Vol 46 (10) ◽  
pp. S283-S286 ◽  
Author(s):  
W. Enge
Keyword(s):  
Primary Energy ◽  
Angular Distributions ◽  
Nuclear Emulsions ◽  
The Core ◽  
Energy Determination

Five electromagnetic cascades of energies 835, 820, 300, 160, and 85 GeV were measured in the emulsions of an emulsion–tungsten stack. For small angles the integral angular distributions of the electrons are shown to be functions of the product E0 × θ (GeV × rad), where E0 is the primary energy of the cascades and θ is the angle up to which electrons were accepted. This is analogous to the well-known fact that the integral radial distributions depend on E0 × R (GeV × r.l.) in the core of the cascade, where R is the radius of a circle inside which were electrons.

Remark on the energy determination of high-energy nucleons by means of the absorption calorimeter

1968 ◽  
Vol 46 (10) ◽  
pp. S1107-S1111 ◽  
Author(s):  
A. Somogyi ◽  
G. Válas ◽  
A. Varga
Keyword(s):  
Distribution Function ◽  
Probability Distribution ◽  
Analytical Method ◽  
Probability Distribution Function ◽  
High Energy ◽  
Primary Energy ◽  
Numerical Calculations ◽  
Energy Determination ◽  
Ionization Calorimeter

The sources of error in energy determinations carried out by means of an ionization calorimeter are well known as are the values of the relevant corrections. Very little if anything is known, however, of the statistical uncertainties of these corrections. An analytical method has been worked out in order to determine the probability that a certain fraction of the primary energy leaves a calorimeter of a given thickness and thus escapes detection. The method makes due allowance for the fluctuation of the inelasticity coefficient. Numerical calculations have been carried out assuming various forms for the probability distribution function of the inelasticity coefficient, and the results of the calculations are given for various calorimeter thicknesses.

Imaging of ribosomal RNA-protein interactions by dark-field STEM

1989 ◽  
Vol 47 ◽  
pp. 250-251
Author(s):  
M. Boublik ◽  
V. Mandiyan ◽  
S. Tumminia ◽  
J.F. Hainfeld ◽  
J.S. Wall
Keyword(s):  
Nucleic Acid ◽  
16S Rrna ◽  
Dark Field ◽  
Radius Of Gyration ◽  
Central Domain ◽  
The Core ◽  
16S Rna ◽  
30S Subunit ◽  
Core Particles

Success in protein-free deposition of native nucleic acid molecules from solutions of selected ionic conditions prompted attempts for high resolution imaging of nucleic acid interactions with proteins, not attainable by conventional EM. Since the nucleic acid molecules can be visualized in the dark-field STEM mode without contrasting by heavy atoms, the established linearity between scattering cross-section and molecular weight can be applied to the determination of their molecular mass (M) linear density (M/L), mass distribution and radius of gyration (RG). Determination of these parameters promotes electron microscopic imaging of biological macromolecules by STEM to a quantitative analytical level. This technique is applied to study the mechanism of 16S rRNA folding during the assembly process of the 30S ribosomal subunit of E. coli. The sequential addition of protein S4 which binds to the 5'end of the 16S rRNA and S8 and S15 which bind to the central domain of the molecule leads to a corresponding increase of mass and increased coiling of the 16S rRNA in the core particles. This increased compactness is evident from the decrease in RG values from 114Å to 91Å (in “ribosomal” buffer consisting of 10 mM Hepes pH 7.6, 60 mM KCl, 2 m Mg(OAc)2, 1 mM DTT). The binding of S20, S17 and S7 which interact with the 5'domain, the central domain and the 3'domain, respectively, continues the trend of mass increase. However, the RG values of the core particles exhibit a reverse trend, an increase to 108Å. In addition, the binding of S7 leads to the formation of a globular mass cluster with a diameter of about 115Å and a mass of ∽300 kDa. The rest of the mass, about 330 kDa, remains loosely coiled giving the particle a “medusa-like” appearance. These results provide direct evidence that 16S RNA undergoes significant structural reorganization during the 30S subunit assembly and show that its interactions with the six primary binding proteins are not sufficient for 16S rRNA coiling into particles resembling the native 30S subunit, contrary to what has been reported in the literature.

Nauwkeurige methode voor de aanwasbepaling van het grondvlak met behulp van de Pressler-boor

1968 ◽  
Vol 12 ◽  
Author(s):  
R. Goossens
Keyword(s):  
Basal Area ◽  
Precise Determination ◽  
Maximum Diameter ◽  
Precise Method ◽  
Maximum Radius ◽  
The Core ◽  
Two Parameters

A precise method for the determination of the increment of the  basal area using the PressIer bore. Refering to  previous research showing that the basal area of the corsica pine could be  characterized by an ellips, we present in this paper a precise method for the  determination of the increment of the basal area. In this method we determine  the direction of the maximum diameter, we measure this diameter and we take a  core in one of the points of tangency of the caliper with the measured tree.  The determination of the diameter perpendicular to the maximum diameter  finishes the work wich is to be done in the forest. From the classical  measurements effectuated on the core and from the measured diameters we can  then determine the form (V) and the excentricity (e). Substituting these two  parameters in the formula 2 or 2', we can also calculate the error of a  radius measured on the core with respect to the representative radius, This  error with them allow us to correct the measured value of the minimum or the  maximum radius and we will be able to do a precise determination of the  increment.

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