7,336 research outputs found
Signatures of the chiral two-pion exchange electromagnetic currents in the 2H and 3He photodisintegration reactions
The recently derived long-range two-pion exchange (TPE) contributions to the
nuclear current operator which appear at next-to-leading order (NLO) of the
chiral expansion are used to describe electromagnetic processes. We study their
role in the photodisintegration of 2H and 3He and compare our predictions with
experimental data. The bound and scattering states are calculated using five
different parametrizations of the chiral next-to-next-to-leading order (N2LO)
nucleon-nucleon (NN) potential which allows us to estimate the theoretical
uncertainty at a given order in the chiral expansion. For some observables the
results are very close to the predictions based on the AV18 NN potential and
the current operator (partly) consistent with this force. In the most cases,
the addition of long-range TPE currents improved the description of the
experimental data.Comment: 11 pages, 6 figures (35 eps files
Electron and Hole Spin Splitting and Photogalvanic Effect in Quantum Wells
A theory of the circular photogalvanic effect caused by spin splitting in
quantum wells is developed. Direct interband transitions between the hole and
electron size-quantized subbands are considered. It is shown that the
photocurrent value and direction depend strongly on the form of the spin-orbit
interaction. The currents induced by structure-, bulk-, and interface-inversion
asymmetry are investigated. The photocurrent excitation spectra caused by spin
splittings in both conduction and valence bands are calculated.Comment: 7 pages, 3 figure
Naming Game on Adaptive Weighted Networks
We examine a naming game on an adaptive weighted network. A weight of
connection for a given pair of agents depends on their communication success
rate and determines the probability with which the agents communicate. In some
cases, depending on the parameters of the model, the preference toward
successfully communicating agents is basically negligible and the model behaves
similarly to the naming game on a complete graph. In particular, it quickly
reaches a single-language state, albeit some details of the dynamics are
different from the complete-graph version. In some other cases, the preference
toward successfully communicating agents becomes much more relevant and the
model gets trapped in a multi-language regime. In this case gradual coarsening
and extinction of languages lead to the emergence of a dominant language,
albeit with some other languages still being present. A comparison of
distribution of languages in our model and in the human population is
discussed.Comment: 22 pages, accepted in Artificial Lif
On-station production of native Speargrass hay in Western Australia
This report documents the practical and economic feasibility of on-station harvesting and production of speargrass hay and haylage and its subsequent feeding to cattle and sheep in the extensive regions of south-eastern Western Australia. Four hundred and ten bales weighing an average 275 kg were produced from a total harvested area of 40.6 ha in the vicinity of Duck Dam on Kanandah Station. In the lead up to harvesting, seasonal conditions were among the best on record. Half of the bales produced were further processed into haylage. Two feeding trials, involving wethers at Arubiddy and steers at Kanandah, were undertaken to evaluate animal performance when freely fed either speargrass hay or haylage, with or without access to supplements. The findings indicate speargrass swards on the Nullarbor Plain can be successfully harvested and made into reasonable quality hay, but the harvesting window of opportunity is short and choosing the best harvesting time is essential. Yields of speargrass hay compared favourably with those of other native grass pastures reported by other workers elsewhere. Wrapping the hay to produce haylage did not improve fodder quality. Speargrass hay supplied sufficient levels of nutrients to maintain livestock, and on-station speargrass hay production on the Nullarbor was a cheaper option than importing hay. Based on our findings, if the highest estimated cost of on-station production is used (1.15/hd/d for cattle and 64/t), feeding costs are 0.06/hd/d for sheep. Additional supplements can significantly improve livestock performance. The quality of speargrass hay produced has not deteriorated over the duration of this project. On-station production of speargrass hay presents a lower environmental risk in terms of introduced weed infestation than importing hay from other areas, but the option would only be commercially viable for those producers with diversified enterprises and/or off-station income.https://researchlibrary.agric.wa.gov.au/bulletins/1218/thumbnail.jp
Fibroblast growth factor treatment of Swiss 3T3 cells activates a subunit S6 kinase that phosphorylates a synthetic peptide substrate.
The Study of Shocks in Three-States Driven-Diffusive Systems: A Matrix Product Approach
We study the shock structures in three-states one-dimensional
driven-diffusive systems with nearest neighbors interactions using a matrix
product formalism. We consider the cases in which the stationary probability
distribution function of the system can be written in terms of superposition of
product shock measures. We show that only three families of three-states
systems have this property. In each case the shock performs a random walk
provided that some constraints are fulfilled. We calculate the diffusion
coefficient and drift velocity of shock for each family.Comment: 15 pages, Accepted for publication in Journal of Statistical
Mechanics: Theory and Experiment (JSTAT
Anything You Can Do, You Can Do Better: Neural Substrates of Incentive-Based Performance Enhancement
Performance-based pay schemes in many organizations share the fundamental assumption that the performance level for a given task will increase as a function of the amount of incentive provided. Consistent with this notion, psychological studies have demonstrated that expectations of reward can improve performance on a plethora of different cognitive and physical tasks, ranging from problem solving to the voluntary regulation of heart rate. However, much less is understood about the neural mechanisms of incentivized performance enhancement. In particular, it is still an open question how brain areas that encode expectations about reward are able to translate incentives into improved performance across fundamentally different cognitive and physical task requirements
Application of the Density Matrix Renormalization Group Method to a Non-Equilibrium Problem
We apply the density matrix renormalization group (DMRG) method to a
non-equilibrium problem: the asymmetric exclusion process in one dimension. We
study the stationary state of the process to calculate the particle density
profile (one-point function). We show that, even with a small number of
retained bases, the DMRG calculation is in excellent agreement with the exact
solution obtained by the matrix-product-ansatz approach.Comment: 8 pages, LaTeX (using jpsj.sty), 4 non-embedded figures, submitted to
J. Phys. Soc. Jp
Analysis of the turbojet engine for propulsion of supersonic fighter airplanes / David S. Gabriel, Richard P. Krebs, E.Clinton Wilcox, Stanley L.Koutz
An analytical investigation was made of two supersonic interceptor type airplanes to determine the most desirable turbojet engine characteristics for this application The airplanes were designed differently primarily because of the amount of subsonic flight incorporated in the flight plan--one flight having none and the other, a cruise radius of 400 nautical miles. Several power plant design variables were varied independently to determine the effect of changes in each parameter on airplane performance. These parameters included compressor pressure ratio, compressor efficiency, turbine-inlet temperature, afterburner temperature, engine specific weight, and air-handling capacity. The effects of using a convergent-divergent exhaust nozzle and of changing the design flight Mach number were also investigated
- …