908 research outputs found
Effect of Mineral Fertiliser Levels on the Yield Quality of Perennial Ryegrass
Perennial ryegrass is a short-lived bunch-grass with shallow root system. The plant is nutritious and palatable and stands up to hard grazing. It will not do well under poor conditions, where fertility or rainfall is low. Perennial ryegrass is a major component in different seed mixtures that are used for grassland management and forage production. This plant is the predominant component in nearly all pasture mixtures, with perennial ryegrass and white or red clover forming the basis for permanent pasture for dairy production and cattle. This grass species plays an important role in grassland productivity and forage quality. Ryegrass requires high fertility levels for good production. The significance of ryegrass to agriculture is reflected by the huge investments in research. The aim of work is to determine the balanced rate of mineral fertilisers in ryegrass seed field
The Leading Particle Effect from Heavy-Quark Recombination
The leading particle effect in charm hadroproduction is an enhancement of the
cross section for a charmed hadron D in the forward direction of the beam when
the beam hadron has a valence parton in common with the D. The large D+/D-
asymmetry observed by the E791 experiment is an example of this phenomenon. We
show that the heavy-quark recombination mechanism provides an economical
explanation for this effect. In particular, the D+/D- asymmetry can be fit
reasonably well using a single parameter whose value is consistent with a
recent determination from charm photoproduction.Comment: Revtex file, 4 pages, 3 figure
Characteristics of alpha projectile fragments emission in interaction of nuclei with emulsion
The properties of the relativistic alpha fragments produced in interactions
of 84^Kr at around 1 A GeV in nuclear emulsion are investigated. The
experimental results are compared with the similar results obtained from
various projectiles with emulsion interactions at different energies. The
total, partial nuclear cross-sections and production rates of alpha
fragmentation channels in relativistic nucleus-nucleus collisions and their
dependence on the mass number and initial energy of the incident projectile
nucleus are investigated. The yields of multiple alpha fragments emitted from
the interactions of projectile nuclei with the nuclei of light, medium and
heavy target groups of emulsion-detector are discussed and they indicate that
the projectile-breakup mechanism seems to be free from the target mass number.
It is found that the multiplicity distributions of alpha fragments are well
described by the Koba-Nielsen-Olesen (KNO) scaling presentation. The mean
multiplicities of the freshly produced newly created charged secondary
particles, normally known as shower and secondary particles associated with
target in the events where the emission of alpha fragments were accompanied by
heavy projectile fragments having Z value larger than 4 seem to be constant as
the alpha fragments multiplicity increases, and exhibit a behavior independent
of the alpha fragments multiplicity.Comment: 33 pages, 8 figures and 3 tables (in press
The health status evaluation of employees of the administrative department in a petrochemical company
The structure and dynamics of illnesses with a temporary loss of working ability have been analyzed in the current article. The research refers to the employees of the main office of the plant «Polymir» JSC «Naftan». It has been revealed that in the research period in the main office no professional diseases were registered. It has been discovered that the long-term average annual morbidity rate for the employees is close to the average morbidity rate with a temporary loss of working ability (further referred to as TLWA)
Fragmentation channels of relativistic Be nuclei in peripheral interactions
Nuclei of Li were accelerated at the JINR Nuclotron. After the
charge-exchange reaction involving these nuclei at an external target a second
Be beam of energy 1.23A GeV was formed. This beam was used to expose
photo-emulsion chambers. The mean free path for inelastic Be interactions
in emulsion =14.00.8 cm coincides within the errors with those
for Li and Li nuclei. More than 10% of the Be events are associated
with the peripheral interactions in which the total charge of the relativistic
fragments is equal to the charge of the Be and in which charged mesons are
not produced. An unusual ratio of the isotopes is revealed in the composition
of the doubly charged Be fragments: the number of He fragments is twice
as large as that of He fragments. In 50% of peripheral interactions, a
Be nucleus decays to two doubly charged fragments. The present paper gives
the channels of the Be fragmentation to charged fragments. In 50% of
events, the Be fragmentation proceeds only to charged fragments involving
no emission of neutrons. Of them, the He+He channel dominates, the
He+d+p and Li+pchannels constitute 10% each. Two events involving no
emission of neutrons are registered in the 3-body He+t+p and He+d+d
channels. The mean free path for the coherent dissociation of relativistic
Be nuclei to He+He is 71 m. The particular features of the
relativistic Be fragmentation in such peripheral interactions are explained
by the He+He 2-cluster structure of the Be nucleus.Comment: 10 pages, 3 figures, 3 tables, conference: Conference on Physics of
Fundamental Interactions, Moscow, Russia, 5-9 Dec 200
The leading particle effect from light quark fragmentation in charm hadroproduction
The asymmetry of and meson production in scattering
observed by the E791 experiment is a typical phenomenon known as the leading
particle effect in charm hadroproducton. We show that the phenomenon can be
explained by the effect of light quark fragmentation into charmed hadrons
(LQF). Meanwhile, the size of the LQF effect is estimated from data of the E791
experiment.
A comparison is made with the estimate of the LQF effect from prompt
like-sign dimuon rate in neutrino experiments. The influence of the LQF effect
on the measurement of nucleon strange distribution asymmetry from charged
current charm production processes is briefly discussed.Comment: 6 latex pages, 1 figure, to appear in EPJ
Enabling comparison of UrQMD with Geant4 hadronic models
Geant4 has an abundant set of physics models that handle the diverse
interaction of particles with matter across a wide energy range. However, there
are also many well established reaction codes currently used in the same fields
where Geant4 is applied. One such code is the Ultra-relativistic Quantum
Molecular Dynamics (UrQMD) model. In order to take advantage of the UrQMD code,
we create a tool to enable comparisons among UrQMD and Geant4 hadronic models.
This tool allows a user to process the output file of UrQMD through Geant4
toolkit, while at the same time, can choose among different Geant4 hadronic
model generators. As an example, the UrQMD model is compared with the HARP-CDP
experimental data and with the Binary and FRITIOF generators, in the framework
of Geant4. It is shown that the UrQMD model can better reproduce charged pion
production for p+Cu and Pb interactions at 3, 8 and 15 GeV/c, and is a good
candidate for Geant4 hadronic models.Comment: 17 pages, 5 Figure
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