3,883 research outputs found
Exchange bias effect and intragranular magnetoresistance in Nd$_{0.84}Sr_{0.16}CoO_3
Electrical transport properties as a function of magnetic field and time have
been investigated in polycrystalline, Nd_{0.84}Sr_{0.16}CoO_3. A strong
exchange bias (EB) effect is observed associated with the fairly large
intragranular magnetoresistance (MR). The EB effect observed in the MR curve is
compared with the EB effect manifested in magnetic hysteresis loop. Training
effect, described as the decrease of EB effect when the sample is successively
field-cycled at a particular temperature, has been observed in the shift of the
MR curve. Training effect could be analysed by the successful models. The EB
effect, MR and a considerable time dependence in MR are attributed to the
intrinsic nanostructure giving rise to the varieties of magnetic interfaces in
the grain interior
Role of loop entropy in the force induced melting of DNA hairpin
Dynamics of a single stranded DNA, which can form a hairpin have been studied
in the constant force ensemble. Using Langevin dynamics simulations, we
obtained the force-temperature diagram, which differs from the theoretical
prediction based on the lattice model. Probability analysis of the extreme
bases of the stem revealed that at high temperature, the hairpin to coil
transition is entropy dominated and the loop contributes significantly in its
opening. However, at low temperature, the transition is force driven and the
hairpin opens from the stem side. It is shown that the elastic energy plays a
crucial role at high force. As a result, the phase diagram differs
significantly with the theoretical prediction.Comment: 9 pages, 8 figures; J. Chem. Phys (2011
On-line Excited-State Laser Spectroscopy of Trapped Short-Lived Ra Ions
As an important step towards an atomic parity violation experiment in one
single trapped Ra ion, laser spectroscopy experiments were performed with
on-line produced short-lived Ra ions. The isotope shift of
the 6\,^2D\,-\,7\,^2P and
6\,^2D\,-\,7\,^2P transitions and the hyperfine structure
constant of the 7\,^2S and 6\,^2D states in Ra
were measured. These values provide a benchmark for the required atomic theory.
A lower limit of ms for the lifetime of the metastable
6\,^2D state was measured by optical shelving.Comment: 4.2 pages, 6 figures, 2 tables
Isotope Shifts of the 6d\,^2D - 7p\,^2P Transition in Trapped Short-Lived Ra
Laser spectroscopy of short-lived radium isotopes in a linear Paul trap has
been performed. The isotope shifts of the 6d\,^2D -
7p\,^2P transition in Ra were measured, which are
sensitive to the short range part of the atomic wavefunctions. The results are
essential experimental input for improving the precision of atomic structure
calculation. This is indispensable for parity violation in Ra aiming at the
determination of the weak mixing angle.Comment: Accepted for publication in Physical Review A as a Rapid
Communicatio
Effect of FCNC mediated Z boson on lepton flavor violating decays
We study the three body lepton flavor violating (LFV) decays , and the semileptonic decay in the flavor changing neutral current (FCNC) mediated boson
model. We also calculate the branching ratios for LFV leptonic B decays,
, , and the
conversion of muon to electron in Ti nucleus. The new physics parameter space
is constrained by using the experimental limits on and
. We find that the branching ratios for and processes could be as large as and . For other LFV B decays the branching ratios are found to be too
small to be observed in the near future.Comment: 15 pages, 8 figures, typos corrected, one more section added, version
to appear in EPJ
SM with four generations: Selected implications for rare B and K decays
We extend our recent work and study implications of the Standard Model with
four generations (SM4) for rare B and K decays. We again take seriously the
several 2-3 anomalies seen in B, decays and interpret them in
the context of this simple extension of the SM. SM4 is also of course of
considerable interest for its potential relevance to dynamical electroweak
symmetry breaking and to baryogenesis. Using experimental information from
processes such as , and mixings, indirect
CP-violation from etc along with oblique corrections, we
constrain the relevant parameter space of the SM4, and find of about
400-600 GeV with a mixing angle in the range of about
(0.05 to 1.4) and with an appreciable CP-odd associated phase,
are favored by the current data. Given the unique role of the CP asymmetry in
due to its gold-plated nature, correlation of that with
many other interesting observables, including the semileptonic asymmetry
() are studied in SM4. We also identify several processes, such as , etc, that are significantly
different in SM4 from the SM. Experimentally the very distinctive process
is also discussed; the branching ratio can be larger or
smaller than in SM, , by a factor of
.Comment: v2: 49 pages, 20 eps figures, Corrected some typos, added few
references and minor changes with regard to direct CP in K pi. Also some
added information to facilitate direct comparison with Buras et al,
arXiv:1002.2126
CP Violation in \tau ->\nu\pi K_S and D->\pi K_S: The Importance of K_S-K_L Interference
The -factories have measured CP asymmetries in the and
modes. The state is identified by its decay to two pions at
a time that is close to the lifetime. Within the Standard Model and many
of its extensions, the asymmetries in these modes come from CP violation in
mixing. We emphasize that the interference between the
amplitudes of intermediate and is as important as the pure
amplitude. Consequently, the measured asymmetries depend on the times over
which the relevant decay rates are integrated and on features of the
experiment.Comment: 4 pages, 4 figure
Agile SoC Development with Open ESP
ESP is an open-source research platform for heterogeneous SoC design. The
platform combines a modular tile-based architecture with a variety of
application-oriented flows for the design and optimization of accelerators. The
ESP architecture is highly scalable and strikes a balance between regularity
and specialization. The companion methodology raises the level of abstraction
to system-level design and enables an automated flow from software and hardware
development to full-system prototyping on FPGA. For application developers, ESP
offers domain-specific automated solutions to synthesize new accelerators for
their software and to map complex workloads onto the SoC architecture. For
hardware engineers, ESP offers automated solutions to integrate their
accelerator designs into the complete SoC. Conceived as a heterogeneous
integration platform and tested through years of teaching at Columbia
University, ESP supports the open-source hardware community by providing a
flexible platform for agile SoC development.Comment: Invited Paper at the 2020 International Conference On Computer Aided
Design (ICCAD) - Special Session on Opensource Tools and Platforms for Agile
Development of Specialized Architecture
The Effect of Salinity on Survival, Growth and Immunity Rate of Sea Cucumber (Holothuria Scabra) Juveniles
Sea cucumber is a stenohaline and osmoconforming organism with a low level of tolerance to salinity change. Salinity of the medium is one of the physiological factors that affect the growth and survival of sea cucumber juveniles. This study was aimed at finding out the effect of different salinities on growth, survival and immunity rate of sea cucumber juveniles (Holothuria scabra) and finding the most suitable salinity level for optimal growth, survival and immunity rate of sea cucumber. This study used a laboratory experimental method and completely randomized design with 5 salinity treatments: 24, 29, 34, 39, and 44 ppt with 3 replications. This study used fifteen 30 L-fiber glass tanks. The sea cucumber juvenile were 4.4 ± 0.2 cm in total length and 5.6 ± 0.3 g in body weight. The juvenile densities were 15 individuals/tank, fed with fresh benthos from a culture once a day in the afternoon. Coelomate was taken from the sea cucumber juveniles from each tank and used to find out the immunity rate dan also the for osmolality. The data collected were analyzed using ANOVA that was followed by Tukey's test at 5% level of significance. The results showed that the salinity of the medium has a significant effect (P < 0.05) on the growth, survival rate and immunity rate of sea cucumber juveniles. The 24 - 34 ppt salinity can support survival rate up to 100%, high growth (6.47 – 7.10 g) and immunity rate (27 – 76 x 104 phagocytic cell/mL), while at the 44 ppt salinity has an effect not only on a low survival rate (55.6%), but also on a bad effect on osmolality (303 ± 3.5 mOs-mol kg-1), growth (3.12 ± 0.34 g), and immunity (209 x 104 phagocytic cell/mL)
Adsorption transition of a self-avoiding polymer chain onto a rigid rod
The subject of this work is the adsorption transition of a long flexible
self-avoiding polymer chain onto a rigid thin rod. The rod is represented by a
cylinder of radius R with a short-ranged attractive surface potential for the
chain monomers. General scaling results are obtained by using renormalization
group arguments in conjunction with available results for quantum field
theories with curved boundaries [McAvity and Osborn 1993 Nucl. Phys. B 394,
728]. Relevant critical exponents are identified and estimated using geometric
arguments.Comment: 19 pages, 4 figures. To appear in: J. Phys.: Condens. Matter, special
issue dedicated to Lothar Schaefer on the occasion of his 60th birthda
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