1,550 research outputs found
Almahata Sitta Meteorite: Combination of Raman Spectroscopy and ElectronMicroprobe analysis within the ureilitic lithologies.
第2回極域科学シンポジウム/第34回南極隕石シンポジウム 11月17日(木) 国立国語研究所 2階講
Determining the unsaturated hydraulic conductivity of a compacted sand-bentonite mixture under constant volume and free-swell conditions
Highly compacted sand-bentonite mixtures are often considered as possible
engineered barriers in deep high-level radioactive waste disposals. In-situ,
the saturation of these barriers from their initially unsaturated state is a
complex hydro-mechanical coupled process in which temperature effects also play
a role. The key parameter of this process is the unsaturated hydraulic
conductivity of the barrier. In this paper, isothermal infiltration experiments
were conducted to determine the unsaturated hydraulic conductivity according to
the instantaneous profile method. To do so, total suction changes were
monitored at different locations along the soil specimen by using resistivity
relative humidity probes. Three constant volume infiltration tests were
conducted showing, unexpectedly, a decrease of the hydraulic conductivity
during infiltration. One test performed under free-swell conditions showed the
opposite and standard trend. These observations were interpreted in terms of
microstructure changes during wetting, both under constant volume and free
swell conditions
Temperature dependence and mechanisms for vortex pinning by periodic arrays of Ni dots in Nb films
Pinning interactions between superconducting vortices in Nb and magnetic Ni
dots were studied as a function of current and temperature to clarify the
nature of pinning mechanisms. A strong current dependence is found for a square
array of dots, with a temperature dependent optimum current for the observation
of periodic pinning, that decreases with temperature as (1-T/Tc)3/2. This same
temperature dependence is found for the critical current at the first matching
field with a rectangular array of dots. The analysis of these results allows to
narrow the possible pinning mechanisms to a combination of two: the interaction
between the vortex and the magnetic moment of the dot and the proximity effect.
Moreover, for the rectangular dot array, the temperature dependence of the
crossover between the low field regime with a rectangular vortex lattice to the
high field regime with a square configuration has been studied. It is found
that the crossover field increases with decreasing temperature. This dependence
indicates a change in the balance between elastic and pinning energies,
associated with dynamical effects of the vortex lattice in the high field
range.Comment: 12 text pages (revtex), 6 figures (1st jpeg, 2nd-6th postscript)
accepted in Physical Review
Considerations on rescattering effects for threshold photo- and electro-production of on deuteron
We show that for the S-state -production in processes and the rescattering effects due to the
transition: (or are cancelled
out due to the Pauli principle. The large values for these effects predicted in
the past may result from the fact that the spin structure of the corresponding
matrix element and the necessary antisymmetrization induced by the presence of
identical protons (or neutrons) in the intermediate state was not taken into
account accurately. One of the important consequences of these considerations
is that photo- and electro-production on deuteron near threshold can
bring direct information about elementary neutron amplitudes.Comment: Add a new sectio
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"Object Categorization: Reversals and Explanations of the Basic-Level Advantage" (Rogers & Patterson, 2007): A simplicity account
T. T. Rogers and K. Patterson (2007), in their article “Object Categorization: Reversals and Explanations of the Basic-Level Advantage” (Journal of Experimental Psychology: General, 136, 451–469), reported an impressive set of results demonstrating a reversal of the highly robust basic-level advantage both in patients with semantic dementia and in healthy individuals engaged in a speeded categorization task. To explain their results, as well as the usual basic-level advantage seen in healthy individuals, the authors employed a parallel distributed processing theory of conceptual knowledge. In this paper, we introduce an alternative way of explaining the results of Rogers and Patterson, which is premised on a more restricted set of assumptions born from standard categorization theory. Specifically, we provide evidence that their results can be accounted for based on the predictions of the simplicity model of unsupervised categorization
Transverse Phase Locking for Vortex Motion in Square and Triangular Pinning Arrays
We analyze transverse phase locking for vortex motion in a superconductor
with a longitudinal DC drive and a transverse AC drive. For both square and
triangular arrays we observe a variety of fractional phase locking steps in the
velocity versus DC drive which correspond to stable vortex orbits. The locking
steps are more pronounced for the triangular arrays which is due to the fact
that the vortex motion has a periodic transverse velocity component even for
zero transverse AC drive. All the steps increase monotonically in width with AC
amplitude. We confirm that the width of some fractional steps in the square
arrays scales as the square of the AC driving amplitude. In addition we
demonstrate scaling in the velocity versus applied DC driving curves at
depinning and on the main step, similar to that seen for phase locking in
charge-density wave systems. The phase locking steps are most prominent for
commensurate vortex fillings where the interstitial vortices form symmetrical
ground states. For increasing temperature, the fractional steps are washed out
very quickly, while the main step gains a linear component and disappears at
melting. For triangular pinning arrays we again observe transverse phase
locking, with the main and several of the fractional step widths scaling
linearly with AC amplitude.Comment: 10 pages, 14 postscript figure
Evidence for host-associated clones of grape phylloxera Daktulosphaira vitifoliae (Hemiptera : Phylloxeridae) in Australia
Grape phylloxera, Daktulosphaira vitifoliae Fitch, is an important pest of grapevines (Vitis vinifera L.) (Vitaceae). Using microsatellite DNA markers it was demonstrated strong associations can exist between D. vitifoliae asexual lineages and vine host type within a vineyard. Also, in excised root bioassays, D. vitifoliae collected from three regions where different genotypic classes predominated showed host-specific differences in life table parameters of reproductive rate and intrinsic rate of increase. Lastly, comparisons of mitochondrial DNA (cytochrome oxidase I) sequences revealed that D. vitifoliae in Australia have paraphyletic origins and fall into two clades partially related to vine host usage. These findings indicate introduction of separate lineages of D. vitifoliae which have close host associations and as such, have important implications for management of this pest in Australia.A.M. Corrie, R. van Heeswijck and A.A. Hoffman
The Dark Sides of Social Policy: From Neoliberalism to Resurgent Right-wing Populism
This Forum Debate explores the confluence of neoliberal, populist, conservative and reactionary influences on contemporary ideologies and practices of social policy, with a focus on the poorer peripheries of global
DN interaction from meson exchange
A model of the DN interaction is presented which is developed in close
analogy to the meson-exchange KbarN potential of the Juelich group utilizing
SU(4) symmetry constraints. The main ingredients of the interaction are
provided by vector meson (rho, omega) exchange and higher-order box diagrams
involving D*N, D\Delta, and D*\Delta intermediate states. The coupling of DN to
the pi-Lambda_c and pi-Sigma_c channels is taken into account. The interaction
model generates the Lambda_c(2595) resonance dynamically as a DN quasi-bound
state. Results for DN total and differential cross sections are presented and
compared with predictions of an interaction model that is based on the
leading-order Weinberg-Tomozawa term. Some features of the Lambda_c(2595)
resonance are discussed and the role of the near-by pi-Sigma_c threshold is
emphasized. Selected predictions of the orginal KbarN model are reported too.
Specifically, it is pointed out that the model generates two poles in the
partial wave corresponding to the Lambda(1405) resonance.Comment: 14 pages, 8 figure
Simulating potential growth and yield of oil palm with PALMSIM
The growing demand for palm oil can be met by reducing the gap between potential yield and actual yield. Simulation models can quantify potential yield, and therefore indicate the scope for intensification. A relatively simple physiological approach was used to develop PALMSIM, which is a model that simulates, on a monthly time step, the potential growth of oil palm as determined by solar radiation in high rainfall environments. The model was used to map potential yield for Indonesia and Malaysia. This map could be used to identify degraded areas that have high yield potential for oil palm
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