1,383 research outputs found
Synthesis of [3H]DNA Complementary to Ovalbumin Messenger RNA: Evidence for Limited Copies of the Ovalbumin Gene in Chick Oviduct
Mg(, )Na reaction study for spectroscopy of Na
The Mg(, )Na reaction was measured at the Holifield
Radioactive Ion Beam Facility at Oak Ridge National Laboratory in order to
better constrain spins and parities of energy levels in Na for the
astrophysically important F()Ne reaction rate
calculation. 31 MeV proton beams from the 25-MV tandem accelerator and enriched
Mg solid targets were used. Recoiling He particles from the
Mg(, )Na reaction were detected by a highly segmented
silicon detector array which measured the yields of He particles over a
range of angles simultaneously. A new level at 6661 5 keV was observed in
the present work. The extracted angular distributions for the first four levels
of Na and Distorted Wave Born Approximation (DWBA) calculations were
compared to verify and extract angular momentum transfer.Comment: 11 pages, 6 figures, proceedings of the 18th International Conference
on Accelerators and Beam Utilization (ICABU2014
Anticonvulsant Activity of Progesterone and Neurosteroids in Progesterone Receptor Knockout Mice
TriSol: a major upgrade of the TwinSol RNB facility
We report here on the recent upgrade of the TwinSol radioactive nuclear beam
(RNB) facility at the University of Notre Dame. The new TriSol system includes
a magnetic dipole to provide a second beamline and a third solenoid which acts
to reduce the size of the radioactive beam on target.Comment: submitted to Nuclear Instruments and Methods
Designing and Piloting a Tool for the Measurement of the Use of Pronunciation Learning Strategies
What appears to be indispensable to drive the field forward and ensure that research findings will be comparable across studies and provide a sound basis for feasible pedagogic proposals is to draw up a classification of PLS and design on that basis a valid and reliable data collection tool which could be employed to measure the use of these strategies in different groups of learners, correlate it with individual and contextual variables, and appraise the effects of training programs. In accordance with this rationale, the present paper represents an attempt to propose a tentative categorization of pronunciation learning strategies, adopting as a point of reference the existing taxonomies of strategic devices (i.e. O'Malley and Chamot 1990; Oxford 1990) and the instructional options teachers have at their disposal when dealing with elements of this language subsystem (e.g. Kelly 2000; Goodwin 2001). It also introduces a research instrument designed on the basis of the classification that shares a number of characteristics with Oxford's (1990) Strategy Inventory for Language Learning but, in contrast to it, includes both Likert-scale and open-ended items. The findings of a pilot study which involved 80 English Department students demonstrate that although the tool requires considerable refinement, it provides a useful point of departure for future research into PLS
Development of the (d,n) proton-transfer reaction in inverse kinematics for structure studies
Transfer reactions have provided exciting opportunities to study the
structure of exotic nuclei and are often used to inform studies relating to
nucleosynthesis and applications. In order to benefit from these reactions and
their application to rare ion beams (RIBs) it is necessary to develop the tools
and techniques to perform and analyze the data from reactions performed in
inverse kinematics, that is with targets of light nuclei and heavier beams. We
are continuing to expand the transfer reaction toolbox in preparation for the
next generation of facilities, such as the Facility for Rare Ion Beams (FRIB),
which is scheduled for completion in 2022. An important step in this process is
to perform the (d,n) reaction in inverse kinematics, with analyses that include
Q-value spectra and differential cross sections. In this way, proton-transfer
reactions can be placed on the same level as the more commonly used
neutron-transfer reactions, such as (d,p), (9Be,8Be), and (13C,12C). Here we
present an overview of the techniques used in (d,p) and (d,n), and some recent
data from (d,n) reactions in inverse kinematics using stable beams of 12C and
16O.Comment: 9 pages, 4 figures, presented at the XXXV Mazurian Lakes Conference
on Physics, Piaski, Polan
Obtaining high resolution excitation functions with an active thick-target approach and validating them with mirror nuclei
Measurement of fusion excitation functions for stable nuclei has largely been
restricted to nuclei with significant natural abundance. Typically, to
investigate neighboring nuclei with low natural abundance has required
obtaining isotopically enriched material. This restriction often limits the
ability to perform such measurements. We report the measurement of a high
quality fusion excitation function for a O beam produced from unenriched
material with 0.038\% natural abundance. The measurement is enabled by using an
active thick-target approach and the accuracy of the result is validated using
its mirror nucleus F and resonances. The result provides important
information about the average fusion cross-section for the oxygen isotopic
chain as a function of neutron excess.Comment: 4 pages, 4 figure
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