1,744 research outputs found
Microwave induced magnetoresistance oscillations at the subharmonics of the cyclotron resonance
The magnetoresistance oscillations, which occur in a two-dimensional electron
system exposed to strong microwave radiation when the microwave frequency
coincides with the n-th subharmonic of the cyclotron frequency
have been investigated for n = 2, 3 and 4. It is shown that these
subharmonic features can be explained within a non-equilibrium energy
distribution function picture without invoking multi-photon absorption
processes. The existence of a frequency threshold above which such oscillations
disappear lends further support to this explanation.Comment: 5 pages, 5 figure
Microwave photoresponse in the 2D electron system caused by intra-Landau level transitions
The influence of microwave radiation on the DC-magnetoresistance of
2D-electrons is studied in the regime beyond the recently discovered zero
resistance states when the cyclotron frequency exceeds the radiation frequency.
Radiation below 30 GHz causes a strong suppression of the resistance over a
wide magnetic field range, whereas higher frequencies produce a non-monotonic
behavior in the damping of the Shubnikov-de Haas oscillations. These
observations are explained by the creation of a non-equilibrium electron
distribution function by microwave induced intra-Landau level transitions.Comment: 4 pages, 5 figure
Inference of the genetic network regulating lateral root initiation in Arabidopsis thaliana
Regulation of gene expression is crucial for organism growth, and it is one of the challenges in Systems Biology to reconstruct the underlying regulatory biological networks from transcriptomic data. The formation of lateral roots in Arabidopsis thaliana is stimulated by a cascade of regulators of which only the interactions of its initial elements have been identified. Using simulated gene expression data with known network topology, we compare the performance of inference algorithms, based on different approaches, for which ready-to-use software is available. We show that their performance improves with the network size and the inclusion of mutants. We then analyse two sets of genes, whose activity is likely to be relevant to lateral root initiation in Arabidopsis, by integrating sequence analysis with the intersection of the results of the best performing methods on time series and mutants to infer their regulatory network. The methods applied capture known interactions between genes that are candidate regulators at early stages of development. The network inferred from genes significantly expressed during lateral root formation exhibits distinct scale-free, small world and hierarchical properties and the nodes with a high out-degree may warrant further investigation
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