NONLINEAR RECIPROCITY: STATISTICAL FOUNDATIONS AND APPLICATIONS TO NONLINEAR EFFECTS IN HEAT TRANSPORT AND CHEMICAL REACTIONS

Robertson has derived from the Liouville equation an exact equation for the maxent distribution which depends on a set of moments. The exact equations for these moments verify predictions of Grad for the Maxwell and Cattaneo relaxation equations in a dilute gas. Nonlinear reciprocity is applied to estimate contributions quadratic in heat flux Q, to thermal conductivity and to second-order effects in Q, diffusion fIux , and traceless pressure P cd in the reaction rate in a dilute gas mixture. All non-linear effects are too small to see· readily

Alternative Views on Entropy Models and Statistical Approaches in Extended Thermodynamics

Three formalisms are considered which challenge extended irreversible thermodynamics (EIT) or derivations thereof. One of these argues that we can control heat flow along a rigid conductor to make internal energy U depend only on temperature T in disagreement with EIT. However, such a process is forbidden in general by an exact equation for second challenge argues that the Boltzmann entropy must be used in a dilute gas, equivalent to EIT with an infinity of variables, and that the Liouville equation cannot describe irreversibility. However, Robertson has shown the Liouville equation to be consistent with irreversible linear heat conduction. Luzzi and Vasconcellos derive EIT approximately from a modified Liouville equation. The Robertson formalism provides a tractable approach without their approximations

Comparative gene expression profiles between heterotic and non-heterotic hybrids of tetraploid Medicago sativa

<p>Abstract</p> <p>Background</p> <p>Heterosis, the superior performance of hybrids relative to parents, has clear agricultural value, but its genetic control is unknown. Our objective was to test the hypotheses that hybrids expressing heterosis for biomass yield would show more gene expression levels that were different from midparental values and outside the range of parental values than hybrids that do not exhibit heterosis.</p> <p>Results</p> <p>We tested these hypotheses in three <it>Medicago sativa </it>(alfalfa) genotypes and their three hybrids, two of which expressed heterosis for biomass yield and a third that did not, using Affymetrix <it>M. truncatula </it>GeneChip arrays. Alfalfa hybridized to approximately 47% of the <it>M. truncatula </it>probe sets. Probe set signal intensities were analyzed using MicroArray Suite v.5.0 (MAS) and robust multi-array average (RMA) algorithms. Based on MAS analysis, the two heterotic hybrids performed similarly, with about 27% of genes showing differential expression among the parents and their hybrid compared to 12.5% for the non-heterotic hybrid. At a false discovery rate of 0.15, 4.7% of differentially expressed genes in hybrids (~300 genes) showed nonadditive expression compared to only 0.5% (16 genes) in the non-heterotic hybrid. Of the nonadditively expressed genes, approximately 50% showed expression levels that fell outside the parental range in heterotic hybrids, but only one of 16 showed a similar profile in the non-heterotic hybrid. Genes whose expression differed in the parents were three times more likely to show nonadditive expression than genes whose parental transcript levels were equal.</p> <p>Conclusion</p> <p>The higher proportions of probe sets with expression level that differed from the parental midparent value and that were more extreme than either parental value in the heterotic hybrids compared to a non-heterotic hybrid were also found using RMA. We conclude that nonadditive expression of transcript levels may contribute to heterosis for biomass yield in alfalfa.</p

Test of Information Theory on the Boltzmann Equation

We examine information theory using the steady-state Boltzmann equation. In a nonequilibrium steady-state system under steady heat conduction, the thermodynamic quantities from information theory are calculated and compared with those from the steady-state Boltzmann equation. We have found that information theory is inconsistent with the steady-state Boltzmann equation.Comment: 12 page

Transformation of maize with the p1 transcription factor directs production of silk maysin, a corn earworm resistance factor, in concordance with a hierarchy of floral organ pigmentation

The maize p1 gene encodes an R2R3-MYB transcription factor that controls the biosynthesis of red flavonoid pigments in floral tissues of the maize plant. Genetic and quantitative trait locus analyses have also associated the p1 gene with the synthesis of maysin, a flavone glycoside from maize silks that confers natural resistance to corn earworm. Here, we show directly that the p1gene induces maysin accumulation in silk tissues. Transformation of maize plants that had low or no silk maysin with p1 transgenes elevated silk maysin concentrations to levels sufficient for corn earworm abiosis. The p1 transgenes also conferred red pigment to pericarp, cob, husk and tassel tissues, as expected; however, different subsets of these tissues were pigmented within individual transgenic plants. Statistical analysis shows that the pigmentation patterns observed amongst the p1 transgenic plants conform to a hierarchy that is similar to the temporal ordering of floral organ initiation. We propose that the observed hierarchy of pigmentation patterns is conferred by variation due to epigenetic control of the p1 transgenes. The production of plants with improved traits through genetic engineering can depend in large part on the achievement of tight organ-specific expression of the introduced transgenes. Our results demonstrate that the production of transgenic plants using a promoter with well-defined tissue specificity, such as the p1 promoter, can result in unexpected variation in tissue specificity amongst the resulting transgenic plants

Some thoughts about nonequilibrium temperature

The main objective of this paper is to show that, within the present framework of the kinetic theoretical approach to irreversible thermodynamics, there is no evidence that provides a basis to modify the ordinary Fourier equation relating the heat flux in a non-equilibrium steady state to the gradient of the local equilibrium temperature. This fact is supported, among other arguments, through the kinetic foundations of generalized hydrodynamics. Some attempts have been recently proposed asserting that, in the presence of non-linearities of the state variables, such a temperature should be replaced by the non-equilibrium temperature as defined in Extended Irreversible Thermodynamics. In the approximations used for such a temperature there is so far no evidence that sustains this proposal.Comment: 13 pages, TeX, no figures, to appear in Mol. Phy