4,989 research outputs found
Agro-Ecological Effects of Sewage Sludge Application to Orchard Grass (Dactylis Glomerata) Fields
Municipal sewage sludge can have a great fertilisation effect. However, its application is limited by high amounts of heavy metals, which have adverse effects on soil biota and plants (Ladonin et al., 2002). Our work was aimed at investigating the sludge effect on a soil-plant system
Dileptons from the nonequilibrium Quark-Gluon Plasma
According to the dynamical quasiparticle model (DQPM) -- matched to reproduce
lattice QCD results in thermodynamic limit, -- the constituents of the strongly
interacting quark-gluon plasma (sQGP) are massive and off-shell quasi-particles
(quarks and gluons) with broad spectral functions. In order to address the
electromagnetic radiation of the sQGP, we derive off-shell cross sections of
, and () reactions taking into account the effective propagators
for quarks and gluons from the DQPM. Dilepton production in In+In collisions at
158 AGeV is studied by implementing these processes into the
parton-hadron-string dynamics (PHSD) transport approach. The microscopic PHSD
transport approach describes the full evolution of the heavy-ion collision:
from the dynamics of quasi-particles in the sQGP phase (when the local energy
density is above GeV/fm) through hadronization and to the
following hadron interactions and off-shell propagation after the
hadronization. A comparison to the data of the NA60 Collaboration shows that
the low mass dilepton spectra are well described by including a collisional
broadening of vector mesons, while the spectra in the intermediate mass range
are dominated by off-shell quark-antiquark annihilation, quark Bremsstrahlung
and gluon-Compton scattering in the nonperturbative QGP. In particular, the
observed softening of the spectra at intermediate masses (1 GeV 3 GeV) is approximately reproduced.Comment: 8 pages, 8 figures, to be published in the Proceedings of the 26th
Winter Workshop on `Nuclear Dynamics', Ochto Rios, Jamaica, 2-9 January, 201
Observations of Lick Standard Stars Using the SCORPIO Multi-Slit Unit at the SAO 6-m Telescope
We present Lick line-index measurements of standard stars from the list of
Worthey. The spectra were taken with the multi-slit unit of the SCORPIO
spectrograph at the 6-m Special Astrophysical observatory telescope. We
describe in detail our method of analysis and explain the importance of using
the Lick index system for studying extragalactic globular clusters. Our results
show that the calibration of our instrumental system to the standard Lick
system can be performed with high confidence.Comment: 12 pages, 3 figure
Omega and AntiOmega production in Pb+Pb and p+p collisions at 30, 40 and 158 AGeV
We report preliminary results on Omega and AntiOmega production in central
Pb+Pb collisions at 30, 40 and 158 AGeV and p + p interactions at 158 GeV. The
midrapidity AntiOmega/Omega ratio is estimated to be 0.45 +- 0.05 and 0.41 +-
0.18 for central Pb+Pb collisions at 158 and 40 AGeV, respectively. The
corresponding value for 158 GeV p+p interactions is 0.67 +- 0.62. For central
Pb+Pb collisions at 158 AGeV fully corrected distributions are obtained. The
inverse slope parameters of the transverse mass spectrum and total yields are
T(Omega) = 276 +- 23 MeV, = 0.47 +- 0.07 and T(AntiOmega) = 285 +- 39
MeV, = 0.15 +- 0.02.Comment: Contribution to the proceedings of "Strangeness in Quark Matter 2003"
(March 2003, Atlantic Beach NC, USA), to be published in Journal of Physics
G., 6 pages, 6 figure
Discovery of an unusual bright eclipsing binary with the longest known period: TYC 2505-672-1 / MASTER OT J095310.04+335352.8
We report on the MASTER Global Robotic Net discovery of an eclipsing binary,
MASTER OT J095310.04+335352.8, previously known as unremarkable star TYC
2505-672-1, which displays extreme orbital parameters. The orbital period
P=69.1 yr is more than 2.5 times longer than that of epsilon-Aurigae, which is
the previous record holder. The light curve is characterized by an extremely
deep total eclipse with a depth of more than 4.5 mag, which is symmetrically
shaped and has a total duration of 3.5 yrs. The eclipse is essentially gray.
The spectra acquired with the Russian 6 m BTA telescope both at minimum and
maximum light mainly correspond to an M0-1III--type red giant, but the spectra
taken at the bottom of eclipse show small traces of a sufficiently hot source.
The observed properties of this system can be better explained as the red giant
eclipsed by a large cloud (the disk) of small particles surrounding the
invisible secondary companion.Comment: 8 figures, 9 pages, Astronomy and astrophysics in prin
Using data of optic sensors and pigment content in leaves for efficient diagnostics of nitrogen nutrition
Received: February 23rd, 2022 ; Accepted: May 16th, 2022 ; Published: August 12th, 2022 ; Correspondence: [email protected] monitoring and diagnostics of a condition of crops permit to make prompt and
proper activities on dressing nitrogen fertilizers. This will allow the plants to use the nitrogen applied
efficiently, and therefore reduce their use in field. Since nitrogen that has not been utilized by plants
is able to escape into the atmosphere or be washed out of the soil with water. The most accurate
diagnostic method is to determine the chemical composition of plants, but it takes quite a long time
and requires laboratory conditions, which is not always possible in the field. One of the promising
methods is photometric diagnostics of crops using optical instruments. Experiment is carried out in
contrasting weather conditions, on soddy-podzolic soil with spring barley and spring rapeseed being
investigated. Results of research show the efficiency of using optic sensors (N-testers) for efficient
diagnostics of nitrogen nutrition of plants. The readings of the device (N-tester) were compared with
the concentration of a and b chlorophyll, determined by a chemical method. Results of diagnostics
with portable photometric device ‘Yara’ are correlating with concentrations of chlorophylls a
(r=0.96) and b (r = 0.91) in spring rapeseed. Moreover, correlation of rapeseed yield and
concentrations of chlorophylls a and b has quantity and inverse relation similar to device indication
(r = -0.81 and r = -0.70 respectively). Results of diagnostics with N-tester ‘Spectroluxe’ are
strongly correlating with chlorophyll concentration. Device indication correlates stronger with
chlorophyll b concentration in spring barley and chlorophyll a concentration in spring rapeseed
(rapeseed was investigated in dryer conditions). Thus, such a modern optical device as N-tester,
whose action is based on measuring the concentration of leafy chlorophyll, can replace chemical
methods and increase the efficiency of nitrogen fertilization, which means increasing the
productivity of plants and reducing the negative impact of unreasonable use of nitrogen fertilizers
On Tamm's problem in the Vavilov-Cherenkov radiation theory
We analyse the well-known Tamm problem treating the charge motion on a finite
space interval with the velocity exceeding light velocity in medium. By
comparing Tamm's formulae with the exact ones we prove that former do not
properly describe Cherenkov radiation terms. We also investigate Tamm's formula
cos(theta)=1/(beta n) defining the position of maximum of the field strengths
Fourier components for the infinite uniform motion of a charge. Numerical
analysis of the Fourier components of field strengths shows that they have a
pronounced maximum at cos(theta)=1/(beta n) only for the charge motion on the
infinitely small interval. As the latter grows, many maxima appear. For the
charge motion on an infinite interval there is infinite number of maxima of the
same amplitude. The quantum analysis of Tamm's formula leads to the same
results.Comment: 28 pages, 8 figures, to be published in J.Phys.D:Appl.Phy
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