5,641 research outputs found
Nuclear effects in positive pion electroproduction on the deuteron near threshold
Positive pion electroproduction from the deuteron near threshold has been
considered within an approach based on the unitary transformation method. The
gauge independence of the treatment is provided by using an explicitly gauge
independent expression for the reaction amplitude. The results of calculations
for kinematics of the experiments on forward-angle meson
electroproduction accomplished at Saclay and Jefferson Laboratory are discussed
and compared with those given by the impulse approximation. It is shown that
the observed behaviour of the cross sections is in accordance with the
calculations based on the pion-nucleon dynamics. In particular, the pion
production rate suppression in the reaction compared to that
for the one can be due to such ``nuclear medium'' effects as
nucleon motion and binding along with Pauli blocking in the final state.Comment: 15 pages, 8 figure
Polarized Proton Pionic Capture in Deuterium as a Probe of 3N Dynamics
The proton analyzing power Ay in pion production reaction pd --> pi0 3He has
been calculated including one- and two-body meson production mechanisms with a
proper treatment of the three-nucleon dynamics and an accurate solution of the
3N bound-state problem for phenomenological two-nucleon potentials. In the
region around the Delta resonance, the structure of the analyzing power can be
understood once interference effects among amplitudes describing intermediate
Delta N formation in different orbital states are considered along with the
additional interference with the S-wave pion production amplitudes. Then, the
inclusion of three-nucleon dynamics in the initial state produces the structure
of the analyzing power that has been observed experimentally.Comment: 9 pages, 5 figure
Magnetic polarizability of hadrons from lattice QCD
We extract the magnetic polarizability from the quadratic response of a
hadron's mass shift in progressively small static magnetic fields. The
calculation is done on a 24x12x12x24 lattice at a = 0.17 fm with an improved
gauge action and the clover quark action. The results are compared to those
from experiments and models where available.Comment: 3 pages, 3 figures, contribution to Lattice 2002 (spectrum
Comment on ``Evidence for Narrow Baryon Resonances in Inelastic pp Scattering''
Compton scattering data are sensitive to the existence of low-mass resonances
reported by Tatischeff et al. We show that such states, with their reported
properties, are excluded by previous Compton scattering experiments.Comment: One page, submitted to PR
Compton Scattering from the Deuteron and Extracted Neutron Polarizabilities
Differential cross sections for Compton scattering from the deuteron were
measured at MAX-lab for incident photon energies of 55 MeV and 66 MeV at
nominal laboratory angles of , , and . Tagged
photons were scattered from liquid deuterium and detected in three NaI
spectrometers. By comparing the data with theoretical calculations in the
framework of a one-boson-exchange potential model, the sum and difference of
the isospin-averaged nucleon polarizabilities, and (in units of fm),
have been determined. By combining the latter with the global-averaged value
for and using the predictions of the Baldin sum rule for
the sum of the nucleon polarizabilities, we have obtained values for the
neutron electric and magnetic polarizabilities of (total) (model) and (total) (model), respectively.Comment: 4 pages, 2 figures, revtex. The text is substantially revised. The
cross sections are slightly different due to improvements in the analysi
Yield and content of biologically active substances in blue honeysuckle fruit (Lonicera caerulea L.) grown in the Forest Steppe of Ukraine
Received: July 28th, 2022 ; Accepted: September 26th, 2022 ; Published: October 20th, 2022
; Correspondence: [email protected] blue honeysuckle (Lonicera caerulea L.) is a relatively new crop in Ukraine, its
industrial cultivation is only 100 hectares. The main constraints are the lack of varieties with high
yield and nutritional value of berries. Therefore, a study of the yield and quality of introduced
varieties is necessary and relevant, both for producers and breeders. With our research, we
determined the potential of the early stage of blue honeysuckle berries under the conditions of
their cultivation in the Forest Steppe of Ukraine and the weather conditions of the year of the
specified region. We assessed how early we can get a crop and set what quality and what it will
be. To clearly understand the quality of the grown fruits, their average weight, size and uniformity
were studied. From nutritional indicators of fruit quality, the content of dry matter, soluble solids,
sugars and titrated acids was studied, from biologically active substances, the content of vitamin
C and total phenolic was determined. It was found that in the zone of the Forest Steppe of Ukraine
from the studied group of varieties, the highest yield potential, 3.13 kg from a bush for the second
year of fruiting and fruit mass 2.4 g, had a variety of Canadian breeding ‘Boreal Beauty’. The
fruits of the cultivars ‘Duet’ (4.3) and ‘Boreal Blizzard’ (4.5) were distinguished by the balance
of taste according to the sugar-acid index, and the maximum amount of total phenolics for the
studied group of varieties was accumulated by the fruits of ‘Boreal Beast’ (1,000 mg 100 g-1
)
Congruence of Human Organizations and Missions: Theory versus Data
1999 Command and Control Research and Technology Symposium (CCRTS), June 29 - July 1, 1999, U.S. Naval War College, Rhode IslandIn this paper, we present a methodology for quantifying the degree of fit between a mission and an
organization based on the closeness between the task structure (i.e., resource requirements and task
interdependence) and the DM-asset allocation across the organization (i.e., amount and distribution
of resource capabilities among DMs, and organizational processes). This closeness is based on
three main characteristics of organizational performance: workload balance, communication
requirements, and DM-DM dependence. These characteristics are affected, in turn, by the
interactions and interdependencies of the organizational processes and the demands of the mission
scenario. Invariably, coordination is essential to achieve good performance because the
information required for decisionmaking is often distributed. However, excessive DM-DM
communication and coordination are harmful to performance, since they increase the processing
workload/overhead that delays task execution. Performance improvements can be obtained by
changing the structure and processes of an organization to decrease the requisite coordination,
while balancing the levels of workload across the organization and reducing inter DM dependence.This work was supported by the Office of Naval Research under contract # N00014-00-1-0101
Neutron polarizabilities investigated by quasi-free Compton scattering from the deuteron
Measuring Compton scattered photons and recoil neutrons in coincidence,
quasi-free Compton scattering by the neutron has been investigated at MAMI
(Mainz) at in an energy range from 200 to 400 MeV.
From the data a polarizability difference of in units of has been
determined. In combination with the polarizability sum deduced from photo absorption data, the neutron electric and
magnetic polarizabilities, and ,
are obtained
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