5,951 research outputs found
Effectiveness of new agri-environment schemes in conserving arable plants in intensively farmed landscapes
Neuroanatomy of the Killer Whale (Orcinus orca) From Magnetic Resonance Images
This article presents the first series of MRI-based anatomically labeled sectioned images of the brain of the killer whale (Orcinus orca). Magnetic resonance images of the brain of an adult killer whale were acquired in the coronal and axial planes. The gross morphology of the killer whale brain is comparable in some respects to that of other odontocete brains, including the unusual spatial arrangement of midbrain structures. There are also intriguing differences. Cerebral hemispheres appear extremely convoluted and, in contrast to smaller cetacean species, the killer whale brain possesses an exceptional degree of cortical elaboration in the insular cortex, temporal operculum, and the cortical limbic lobe. The functional and evolutionary implications of these features are discussed
Calculation of the crystal-melt interfacial free energy of succinonitrile from molecular simulation
This is the publisher's version, also available electronically from http://scitation.aip.org/content/aip/journal/jcp/124/4/10.1063/1.2149859
Supercooled-liquid and plastic-crystalline state in succinonitrile-glutaronitrile mixtures
We report a thorough characterization of the glassy phases of mixtures of
succinonitrile and glutaronitrile via dielectric spectroscopy and differential
scanning calorimetry. This system is revealed to be one of the rare examples
where both glassy states of matter, a structurally disordered supercooled
liquid and an orientationally disordered plastic crystal, can be prepared in
the same material. Both disordered states can be easily supercooled, finally
arriving at a structural-glass or a glassy-crystal state. Detailed
investigations using broadband dielectric spectroscopy enable a comparison of
the glassy dynamics in both phases. Just as previously demonstrated for
supercooled-liquid and plastic-crystalline ethanol, our experiments reveal very
similar relaxational behavior and glass temperatures of both disordered states.
Thus the prominent role of orientational degrees of freedom in the glass
transition, suggested on the basis of the findings for ethanol, is fully
corroborated by the present work. Moreover, the fragilities of both phases are
determined and compared for different mixtures. The findings can be well
understood within an energy-landscape based explanation of fragility.Comment: 8 pages, 7 figure
Realization of logically labeled effective pure states for bulk quantum computation
We report the first use of "logical labeling" to perform a quantum
computation with a room-temperature bulk system. This method entails the
selection of a subsystem which behaves as if it were at zero temperature -
except for a decrease in signal strength - conditioned upon the state of the
remaining system. No averaging over differently prepared molecules is required.
In order to test this concept, we execute a quantum search algorithm in a
subspace of two nuclear spins, labeled by a third spin, using solution nuclear
magnetic resonance (NMR), and employing a novel choice of reference frame to
uncouple nuclei.Comment: PRL 83, 3085 (1999). Small changes made to improve readability and
remove ambiguitie
Temperature development of glassy alpha-relaxation dynamics determined by broadband dielectric spectroscopy
We present the temperature dependence of alpha-relaxation times of 13 glass
formers determined from broadband dielectric spectroscopy, also including data
from aging measurements. The data sets partly cover relaxation-time ranges of
up to 16 decades enabling a critical test of the validity of model predictions.
For this purpose, the data are provided for electronic download. Here we employ
these results to test the applicability of the Vogel-Fulcher-Tammann equation
and a recently proposed new approach that was demonstrated to provide superior
fits of a vast collection of viscosity data.Comment: 6 pages, 5 figures, final version with minor revisions according to
referee demands. The relaxation time data published in the present work can
be downloaded at http://link.aps.org/supplemental/10.1103/PhysRevE.81.05150
Random Sequential Adsorption: From Continuum to Lattice and Pre-Patterned Substrates
The random sequential adsorption (RSA) model has served as a paradigm for
diverse phenomena in physical chemistry, as well as in other areas such as
biology, ecology, and sociology. In the present work, we survey aspects of the
RSA model with emphasis on the approach to and properties of jammed states
obtained for large times in continuum deposition versus that on lattice
substrates, and on pre-patterned surfaces. The latter model has been of recent
interest in the context of efforts to use pre-patterning as a tool to improve
selfassembly in micro- and nanoscale surface structure engineering
Relaxation dynamics and ionic conductivity in a fragile plastic crystal
We report a thorough characterization of the dielectric relaxation behavior
and the ionic conductivity in the plastic-crystalline mixture of 60%
succinonitrile and 40% glutaronitrile. The plastic phase can be easily
supercooled and the relaxational behavior is investigated by broadband
dielectric spectroscopy in the liquid, plastic crystalline, and glassy crystal
phases. The very pronounced alpha-relaxation found in the spectra is
characterized in detail. From the temperature dependence of the
alpha-relaxation time, a fragility parameter of 62 was determined making this
material one of the most fragile plastic-crystalline glass formers. A
well-pronounced secondary and faint indications for a third relaxation process
were found, the latter most likely being of Johari-Goldstein type. In addition,
relatively strong conductivity contributions were detected in the spectra
exhibiting the typical features of ionic charge transport.Comment: 8 pages, 7 figure
Bottom Production
We review the prospects for bottom production physics at the LHC.Comment: 74 pages, Latex, 71 figures, to appear in the Report of the ``1999
CERN Workshop on SM physics (and more) at the LHC'', P. Nason, G. Ridolfi, O.
Schneider G.F. Tartarelli, P. Vikas (conveners
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