113 research outputs found
Impact of Chromosomal Rearrangements on the Interpretation of Lupin Karyotype Evolution
Plant genome evolution can be very complex and challenging to describe, even within a
genus. Mechanisms that underlie genome variation are complex and can include whole-genome
duplications, gene duplication and/or loss, and, importantly, multiple chromosomal
rearrangements. Lupins (Lupinus) diverged from other legumes approximately 60 mya. In contrast
to New World lupins, Old World lupins show high variability not only for chromosome numbers
(2n = 32–52), but also for the basic chromosome number (x = 5–9, 13) and genome size. The
evolutionary basis that underlies the karyotype evolution in lupins remains unknown, as it has so
far been impossible to identify individual chromosomes. To shed light on chromosome changes and
evolution, we used comparative chromosome mapping among 11 Old World lupins, with Lupinus
angustifolius as the reference species. We applied set of L. angustifolius-derived bacterial artificial
chromosome clones for fluorescence in situ hybridization. We demonstrate that chromosome
variations in the species analyzed might have arisen from multiple changes in chromosome
structure and number. We hypothesize about lupin karyotype evolution through polyploidy and
subsequent aneuploidy. Additionally, we have established a cytogenomic map of L. angustifolius
along with chromosome markers that can be used for related species to further improve
comparative studies of crops and wild lupins
Superscaling in dilute Fermi gas and its relation to general properties of the nucleon momentum distribution in nuclei
The superscaling observed in inclusive electron scattering is described
within the dilute Fermi gas model with interaction between the particles. The
comparison with the relativistic Fermi gas (RFG) model without interaction
shows an improvement in the explanation of the scaling function in
the region , where the RFG result is . It is found
that the behavior of for depends on the particular
form of the general power-law asymptotics of the momentum distribution
at large . The best agreement with the empirical
scaling function is found for in agreement with the asymptotics
of in the coherent density fluctuation model where . Thus,
superscaling gives information about the asymptotics of and the NN
forces.Comment: 6 pages, 5 figures, accepted for publication in Physical Review
Event Generators for Bhabha Scattering
The results obtained by the "Event Generators for Bhabha Scattering" working
group during the CERN Workshop "Physics at LEP2" (1994/1995) are presented.Comment: 70 pages, PostScript file. To appear in the Report of the Workshop on
Physics at LEP2, G. Altarelli T. Sjostrand and F. Zwirner ed
Constraining the Hadronic Contributions to the Muon Anomalous Magnetic Moment
The mini-proceedings of the Workshop on "Constraining the hadronic
contributions to the muon anomalous magnetic moment" which included the "13th
meeting of the Radio MonteCarLow WG" and the "Satellite meeting R-Measurements
at BES-III" held in Trento from April 10th to 12th, 2013, are presented. This
collaboration meeting aims to bring together the experimental e+e- collider
communities from BaBar, Belle, BESIII, CMD2, KLOE, and SND, with theorists
working in the fields of meson transitions form factors, hadronic contributions
to (g-2)_\mu and effective fine structure constant, and development of Monte
Carlo generator and Radiative Corrections for precision e+e- and tau physics.Comment: 45 pages, 17 contributions. Editors: P. Masjuan and G. Venanzon
The influence of zinc-methionine bioplex supplementation to pregnant and lactating sheep on selected wool parameters
The most important nutrients affecting wool production
include sulfur amino acids, such as methionine, and minerals, such as zinc, and
their deficiency may cause wool production decrease. The aim of this study
was to evaluate an effect of zinc and methionine chelate addition on the
qualitative characteristics of Merino ewes wool and zinc content in wool
fibers and on their surface. Histological evaluation of fibers was also
performed. The study included 22 Polish Merino ewes divided into two
groups: control and experimental (0.4 g chelates daily per head). The
experiment lasted for 4 months (3.5 months of pregnancy and 2 weeks of early
lactation). The length, thickness and breaking force of wool fibers were
higher in the experimental group compared to the control group. Higher
content of zinc in wool of sheep from the experimental group was also
demonstrated. The histological structure of fibers from both groups did not
differ, as the content of zinc on their surface. It can be concluded on the
basis of the obtained results that the addition of chelates favorably
influenced the thickness compensation of wool fibers and amount of wool
obtained from sheep during pregnancy and early lactation, as well as
mechanical features of wool.</p
First Order Static Excitation Potential: Scheme for Excitation Energies and Transition Moments
We present an approximation scheme for the calculation of the principal
excitation energies and transition moments of finite many-body systems. The
scheme is derived from a first order approximation to the self energy of a
recently proposed extended particle-hole Green's function. A hermitian
eigenvalue problem is encountered of the same size as the well-known Random
Phase Approximation (RPA). We find that it yields a size consistent description
of the excitation properties and removes an inconsistent treatment of the
ground state correlation by the RPA. By presenting a hermitian eigenvalue
problem the new scheme avoids the instabilities of the RPA and should be well
suited for large scale numerical calculations. These and additional properties
of the new approximation scheme are illuminated by a very simple exactly
solvable model.Comment: 15 pages revtex, 1 eps figure included, corrections in Eq. (A1) and
Sec. II
The present theoretical error on the Bhabha scattering cross section in the luminometry region at LEP
The results concerning the theoretical evaluation of the small-angle Bhabha Scattering cross section obtained during the Workshop on Physics at LEP2 (CERN, Geneva, Switzerland, 1995) by the Working Group ``Event Generators for Bhabha Scattering'' are summarized. The estimate of the theoretical error on the cross section in the luminometry region is updated
Scaling violations: Connections between elastic and inelastic hadron scattering in a geometrical approach
Starting from a short range expansion of the inelastic overlap function,
capable of describing quite well the elastic pp and scattering data,
we obtain extensions to the inelastic channel, through unitarity and an impact
parameter approach. Based on geometrical arguments we infer some
characteristics of the elementary hadronic process and this allows an excellent
description of the inclusive multiplicity distributions in and
collisions. With this approach we quantitatively correlate the violations of
both geometrical and KNO scaling in an analytical way. The physical picture
from both channels is that the geometrical evolution of the hadronic
constituents is principally reponsible for the energy dependence of the
physical quantities rather than the dynamical (elementary) interaction itself.Comment: 16 pages, aps-revtex, 11 figure
Determination of Matter Surface Distribution of Neutron-rich Nuclei
We demonstrate that the matter density distribution in the surface region is
determined well by the use of the relatively low-intensity beams that become
available at the upcoming radioactive beam facilities. Following the method
used in the analyses of electron scattering, we examine how well the density
distribution is determined in a model-independent way by generating pseudo data
and by carefully applying statistical and systematic error analyses. We also
study how the determination becomes deteriorated in the central region of the
density, as the quality of data decreases. Determination of the density
distributions of neutron-rich nuclei is performed by fixing parameters in the
basis functions to the neighboring stable nuclei. The procedure allows that the
knowledge of the density distributions of stable nuclei assists to strengthen
the determination of their unstable isotopes.Comment: 41 pages, latex, 27 figure
Winter Bird Assemblages in Rural and Urban Environments: A National Survey
Urban development has a marked effect on the ecological and behavioural traits of many living
organisms, including birds. In this paper, we analysed differences in the numbers of wintering
birds between rural and urban areas in Poland. We also analysed species richness
and abundance in relation to longitude, latitude, human population size, and landscape
structure. All these parameters were analysed using modern statistical techniques incorporating
species detectability. We counted birds in 156 squares (0.25 km2 each) in December
2012 and again in January 2013 in locations in and around 26 urban areas across Poland
(in each urban area we surveyed 3 squares and 3 squares in nearby rural areas). The influence
of twelve potential environmental variables on species abundance and richness was
assessed with Generalized Linear Mixed Models, Principal Components and Detrended
Correspondence Analyses. Totals of 72 bird species and 89,710 individual birds were recorded
in this study. On average (±SE) 13.3 ± 0.3 species and 288 ± 14 individuals were recorded
in each square in each survey. A formal comparison of rural and urban areas
revealed that 27 species had a significant preference; 17 to rural areas and 10 to urban areas. Moreover, overall abundance in urban areas was more than double that of rural
areas. There was almost a complete separation of rural and urban bird communities. Significantly
more birds and more bird species were recorded in January compared to December.
We conclude that differences between rural and urban areas in terms of winter conditions
and the availability of resources are reflected in different bird communities in the two
environments
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