5,276 research outputs found
Theoretical study of EAS hadronic structure
The structure of extensive air showers (EAS) is determined mainly by the energetic hadrons. They are strongly collimated in the core of the shower and essential difficulties are encountered for resolution of individual hadrons. The properties for resolution are different from the variety of hadron detectors used in EAS experiments. This is the main difficulty in obtaining a general agreement between actually registered data with different detectors. The most plausible source for disagreement is the uncertainty in determination of the energy of individual hadrons. This research demonstrates that a better agreement can be obtained with the average tendency of hadronic measurements if one assumes a larger coefficient of inelasticity and stronger energy increase of the total inelastic cross section in high energy pion interactions. EAS data above 10 to the 5th power GeV are revealing a faster development of hadronic cascades in the air then can be expected by extrapolating the parameters of hadron interactions obtained in accelerator measurements
Implication of EAS data for the study of primary cosmic rays above 10 to the 5th power GeV
Due to the strong decrease of the energetic cosmic ray flux its direct detection at the top of atmosphere with aircraft is limited at the present time to about 100,000 GeV. The intensity of all primary particles can be approximated in the range 100 to 100,000 GeV by power function with power index 2.65. There are predominantly protons and the rest is represented by several groups of nuclei. In the range of 100,000 to 10 to the 8th power GeV considerable disagreement is most probably connected with the uncertainity of the indirect derivation of the parameters of extensive air showers. Results for the primary spectrum in the range to the 8th power GeV, obtained by implication of extensive air showers (EAS) data from mountain altitudes are discussed
General consequences of the violated Feynman scaling
The problem of scaling of the hadronic production cross sections represents an outstanding question in high energy physics especially for interpretation of cosmic ray data. A comprehensive analysis of the accelerator data leads to the conclusion of the existence of breaked Feynman scaling. It was proposed that the Lorentz invariant inclusive cross sections for secondaries of a given type approaches constant in respect to a breaked scaling variable x sub s. Thus, the differential cross sections measured in accelerator energy can be extrapolated to higher cosmic ray energies. This assumption leads to some important consequences. The distribution of secondary multiplicity that follows from the violated Feynman scaling using a similar method of Koba et al is discussed
Experiment K-6-12. Morphometric studies of atrial or granules and hepatocytes. Part 1: Morphometric study of the liver; Part 2: The atrial granular accumulations
The livers of flight, F, rats from the Cosmos 1887 mission were markedly paler and heavier than those of the synchronous, S, and vivarium, V, controls. In the F group, microscopic study revealed extensive hepatocytic intracytoplasmic vacuolization which was moderate in the S and minimal in the V groups. The vacuoles were not sudanophilic and therefore were regarded as glycogenic in origin. To obtain objective data concerning the extent of the vacuolization, livers were examined by computer assisted morphometry. Measurements of profile area and perimeter of the hepatocyte nuclei and vacuoles were evaluated according to stereological principles. Results indicated that the volume density of the nuclei was less in the F group than in the S(p equal less than 0.0002) and V(p equal less than 0.001) groups. Mean volume of individual nuclei did not differ. Volume density of the vacuoles was greater in the F than in the V group (p equal less than 0.02) while their mean diameter was less (p equal less than 0.05). To ascertain the relationship between increase in liver weight of the flight animals and the results of this study, an assumption was made that the specific gravity of the vacuolar contents was similar to the other extranuclear components of the hepatocyte. On that basis, calculations showed that the elevated vacuolar volume density in the flight group did not cause the increased liver weight in those animals, but that the non-nuclear, non-vacuolar parenchymal compartment did contribute significantly. Factors that may have played a causal role in liver weight and vacuolar compartment increases are discussed
A statistical mechanics framework for multi-particle production in high energy reactions
We deduce the particle distributions in particle collisions with
multihadron-production in the framework of mechanical statistics. They are
derived as functions of x, P_T^2 and the rest mass of different species for a
fixed total number of all produced particles, inelasticity and total transverse
energy. For P_T larger than the mass of each particle we get the behaviour
\frac{dn_i}{dP_T} \sim \sqrt{P_T} e^{-\frac{P_T}{T_H}} Values of _\pi,
_K, and _{\bar{p}} in agreement with experiment are found by taking
T_H=180MeV (the Hagedorn temperature).Comment: 9 pages, RevTe
Influence of salicylic acid on phytochelatin synthesis in Zea mays during Cd stress
Abstract: Presoaking maize (Zea mays) seeds in salicylic acid (SA) reduces damage caused by cadmium. In the present work the possible
role of phytochelatins (PCs) in SA-mediated protection against Cd toxicity was investigated. Seeds were presoaked in 0.5 mM SA, and
seedlings were grown in hydroponic solution containing 0, 0.01, 0.015, or 0.025 mM Cd. Treatment with Cd increased the PC levels in
maize roots, but only slight changes were observed in the leaves. Long-term exposure to Cd decreased the phytochelatin synthase (PCS)
activity in the roots and led to an increase in PCS and glutathione reductase (GR) activities in maize leaves. Although presoaking seeds
in SA solution before exposure to Cd may reduce the level of heavy metal injury and has an effect on the composition of individual PCs,
this protection is not directly connected with the altered regulation of PCs
The research works of Coulomb and Amontons and generalized laws of friction
The paper is devoted to the contributions of Coulomb and Amontons to the physics of friction from the viewpoint of current discussions and attempts to formulate generalized laws of friction
BRICS influence on global capitalist economy
The paper surveys the BRICS’ performance in the world during the last fifteen years. It analyses the economic environment as well as the possibility of rising of a possible new “global power”. The paper presents the statistical data on economic growth, international trade, population and currency reserves of the BRICS countrie
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