442 research outputs found
Coupled-channels analyses for large-angle quasi-elastic scattering in massive systems
We discuss in detail the coupled-channels approach for the large-angle
quasi-elastic scattering in massive systems, where many degrees of freedom may
be involved in the reaction. We especially investigate the effects of single,
double and triple phonon excitations on the quasi-elastic scattering for
Ti,Cr,Fe,Ni and ZnPb systems, for
which the experimental cross sections have been measured recently. We show that
the present coupled-channels calculations well account for the overall width of
the experimental barrier distribution for these systems. In particular, it is
shown that the calculations taking into account single quadrupole phonon
excitations in Ti and triple octupole phonon excitations in Pb
reasonably well reproduce the experimental quasi-elastic cross section and
barrier distribution for the TiPb reaction. On the other hand,
Cr,Fe,Ni and ZnPb systems seem to require
the double quadrupole phonon excitations in the projectiles in order to
reproduce the experimental data.Comment: 11 pages, 6 figure
Coexistence of Bloch electrons and glassy electrons in Ca10(Ir4As8)(Fe2_xIrxAs2)5 revealed by angle-resolved photoemission spectroscopy
Angle-resolved photoemission spectroscopy of Ca10(Ir4As8)(Fe2_xIrxAs2)5 shows
that the Fe 3d electrons in the FeAs layer form the hole-like Fermi pocket at
the zone center and the electron-like Fermi pockets at the zone corners as
commonly seen in various Fe-based superconductors. The FeAs layer is heavily
electron doped and has relatively good two dimensionality. On the other hand,
the Ir 5d electrons are metallic and glassy probably due to atomic disorder
related to the Ir 5d orbital instability. Ca10(Ir4As8)(Fe2_xIrxAs2)5 exhibits a
unique electronic state where the Bloch electrons in the FeAs layer coexist
with the glassy electrons in the Ir4As8 layer.Comment: 4 pages, 3 figure
Development of genomic simple sequence repeat markers for yam
Yam (
Dioscorea
spp.) is a major staple crop
widely cultivated for its starchy tubers. To date,
very few marker resources are publicly avail
-
able as tools for genetic and genomic studies of
this economically important crop. In this study,
90 simple sequence repeat (SSR) markers were
developed from an enriched genomic library of
yellow Guinea yam (
D. cayenensis
Lam.). Cross-
amplification revealed that 85 (94.4%) and 51
(56.7%) of these SSRs could be successfully
transferred to the two major cultivated species
of
D. rotundata
Poir. and
D. alata
L., respec
-
tively. Polymorphisms in 30 markers selected
on the basis of reliability and reproducibility of
DNA bands were evaluated using a panel of 12
D. cayenensis
, 48
D. rotundata
, and 48
D. alata
accessions. Accordingly, number of alleles
per locus ranged from 2 to 8 in
D. cayenensis
(mean = 3.9), 3 to 30 in
D. rotundata
(mean =
13.9), and 2 to 22 in
D. alata
(mean = 12.1). The
average observed and expected heterozygosi
-
ties were 0.156 and 0.634 (
D. cayenensis
), 0.326
and 0.853 (
D. rotundata
), and 0.247 and 0.836
(
D. alata
), respectively. Clustering based on six
SSRs that were polymorphic in at least four of
the five cultivated
Dioscorea
species studied,
including
D. cayenensis
,
D. rotundata
,
D. alata
,
D. dumetorum
(Kunth) Pax., and
D. bulbifera
L.,
detected groups consistent with the phyloge
-
netic relationships of the species except for
D.
dumetorum
. These new SSR markers are invalu
-
able resources for applications such as genetic
diversity analysis and marker-assisted breedingYam (
Dioscorea
spp.) is a major staple crop
widely cultivated for its starchy tubers. To date,
very few marker resources are publicly avail
-
able as tools for genetic and genomic studies of
this economically important crop. In this study,
90 simple sequence repeat (SSR) markers were
developed from an enriched genomic library of
yellow Guinea yam (
D. cayenensis
Lam.). Cross-
amplification revealed that 85 (94.4%) and 51
(56.7%) of these SSRs could be successfully
transferred to the two major cultivated species
of
D. rotundata
Poir. and
D. alata
L., respec
-
tively. Polymorphisms in 30 markers selected
on the basis of reliability and reproducibility of
DNA bands were evaluated using a panel of 12
D. cayenensis
, 48
D. rotundata
, and 48
D. alata
accessions. Accordingly, number of alleles
per locus ranged from 2 to 8 in
D. cayenensis
(mean = 3.9), 3 to 30 in
D. rotundata
(mean =
13.9), and 2 to 22 in
D. alata
(mean = 12.1). The
average observed and expected heterozygosi
-
ties were 0.156 and 0.634 (
D. cayenensis
), 0.326
and 0.853 (
D. rotundata
), and 0.247 and 0.836
(
D. alata
), respectively. Clustering based on six
SSRs that were polymorphic in at least four of
the five cultivated
Dioscorea
species studied,
including
D. cayenensis
,
D. rotundata
,
D. alata
,
D. dumetorum
(Kunth) Pax., and
D. bulbifera
L.,
detected groups consistent with the phyloge
-
netic relationships of the species except for
D.
dumetorum
. These new SSR markers are invalu
-
able resources for applications such as genetic
diversity analysis and marker-assisted breedin
β-delayed neutron and γ-ray spectroscopy of ^<17>C utilizing spin-polarized ^<17>B
Excited states in ^C were investigated through the measurement of β -delayed neutrons and γ rays emitted in the β decay of ^B. In the measurement, three negative-parity states and two inconclusive states were identified in ^C above the neutron threshold energy, and seven γ lines were identified in a β -delayed multiple neutron emission of the ^Bβ decay. From these transitions, the β-decay scheme of ^B was determined. In particular, a de-excitation 1766-keVγ line from the first excited state of ^C was observed in coincidence with the emitted β-delayed neutrons, and this changes the previously reported β-decay scheme of ^B and level structure of ^C. In the present work, the β-NMR technique is combined with the β-delayed particle measurements using a fragmentation-induced spin-polarized ^B beam. This new scheme allows us to determine the spin parity of β-decay feeding excited states based on the difference in the discrete β-decay asymmetry parameters, provided the states are connected through the Gamow-Teller transition. In this work, I^π=1/2^−, 3/2^−, and (5/2^−) are assigned to the observed states at E_x = 2.71(2), 3.93(2), and 4.05(2) MeV in ^C, respectively
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