1,206 research outputs found
The communicative wheel: Symptom, signal, and model in multimodal communication
This paper addresses the need for a model of communication with a new, holistic conception of language within it. The resultant process model is called the Communicative Wheel. It consists of three communicative products: the sender’s input corresponding to his/her experience of a situation (symptom), an output corresponding to a piece of information to the receiver (signal), and the receiver’s intake corresponding to a description of the situation referred to (model). What the model of the wheel suggests, is that the understanding of ‘utterance’ as symbolic needs to be replaced by an understanding of it as indexical
The Effect of the Housing Boom on Farm Land Values via Tax-Deferred Exchanges
This project examines Section 1031 of the Internal Revenue Code and agriculture land exchanges. Stakeholders in rural communities and agriculture are particularly interested in Section 1031 because the recent growth in transaction values of farmland may have, in part, been stimulated by Section 1031 land exchanges. Further, although many have speculated that such exchanges are widely used, little empirical research exists about the provision. We examine the theory of exchanges and develop a theoretical premium value for exchanges. We also present the first evidence of like-kind exchanges involving farmland using Federal tax data.Like-Kind Exchange, Capital Gains Tax, Agricultural Land, Land Economics/Use, Public Economics, Q15, H24,
Maximizing ecological and evolutionary insight in bisulfite sequencing data sets
Genome-scale bisulfite sequencing approaches have opened the door to ecological and evolutionary studies of DNA methylation in many organisms. These approaches can be powerful. However, they introduce new methodological and statistical considerations, some of which are particularly relevant to non-model systems. Here, we highlight how these considerations influence a study’s power to link methylation variation with a predictor variable of interest. Relative to current practice, we argue that sample sizes will need to increase to provide robust insights. We also provide recommendations for overcoming common challenges and an R Shiny app to aid in study design
Radiation-Induced Magnetoresistance Oscillations in a 2D Electron Gas
Recent measurements of a 2D electron gas subjected to microwave radiation
reveal a magnetoresistance with an oscillatory dependence on the ratio of
radiation frequency to cyclotron frequency. We perform a diagrammatic
calculation and find radiation-induced resistivity oscillations with the
correct period and phase. Results are explained via a simple picture of current
induced by photo-excited disorder-scattered electrons. The oscillations
increase with radiation intensity, easily exceeding the dark resistivity and
resulting in negative-resistivity minima. At high intensity, we identify
additional features, likely due to multi-photon processes, which have yet to be
observed experimentally.Comment: 5 pages, 3 figures; final version as published in Phys Rev Let
Microwave Conductivity due to Scattering from Extended Linear Defects in d-Wave Superconductors
Recent microwave conductivity measurements of detwinned, high-purity,
slightly overdoped YBaCuO crystals reveal a linear
temperature dependence and a near-Drude lineshape for temperatures between 1
and 20 K and frequencies ranging from 1 to 75 GHz. Prior theoretical work has
shown that simple models of scattering by point defects (impurities) in d-wave
superconductors are inconsistent with these results. It has therefore been
suggested that scattering by extended defects such as twin boundary remnants,
left over from the detwinning process, may also be important. We calculate the
self-energy and microwave conductivity in the self-consistent Born
approximation (including vertex corrections) for a d-wave superconductor in the
presence of scattering from extended linear defects. We find that in the
experimentally relevant limit (), the
resulting microwave conductivity has a linear temperature dependence and a
near-Drude frequency dependence that agrees well with experiment.Comment: 13 pages, 7 figure
Microwave conductivity of a d-wave superconductor disordered by extended impurities: a real-space renormalization group approach
Using a real-space renormalization group (RSRG) technique, we compute the
microwave conductivity of a d-wave superconductor disordered by extended
impurities. To do this, we invoke a semiclassical approximation which naturally
accesses the Andreev bound states localized near each impurity. Tunneling
corrections (which are captured using the RSRG) lead to a delocalization of
these quasiparticles and an associated contribution to the microwave
conductivity.Comment: 8 pages, 4 figures. 2 figures added to previous versio
Transport properties in the d-density wave state: Wiedemann-Franz law
We study the Wiedemann-Franz (WF) law in the d-density wave (DDW) model. Even
though the opening of the DDW gap profoundly modifies the electronic
density of states and makes it dependent on energy, the value of the WF ratio
at zero temperature (T=0) remains unchanged. However, neither electrical nor
thermal conductivity display universal behavior. For finite temperature, with T
greater than the value of the impurity scattering rate at zero frequency
i.e. , the usual WF ratio is obtained only in
the weak scattering limit. For strong scattering there are large violations of
the WF law.Comment: 1 figur
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