General Relativistic Contributions in Transformation Optics

One potentially realistic specification for devices designed with transformation optics is that they operate with high precision in curved space-time, such as Earth orbit. This raises the question of what, if any, role does space-time curvature play in determining transformation media? Transformation optics has been based on a three-vector representation of Maxwell's equations in flat Minkowski space-time. I discuss a completely covariant, manifestly four-dimensional approach that enables transformations in arbitrary space-times, and demonstrate this approach for stable circular orbits in the spherically symmetric Schwarzschild geometry. Finally, I estimate the magnitude of curvature induced contributions to satellite-borne transformation media in Earth orbit and comment on the level of precision required for metamaterial fabrication before such contributions become important.Comment: 14 pages, 3 figures. Latest version has expanded analysis, corresponds to published versio

Long-Term Evolution and Revival Structure of Rydberg Wave Packets for Hydrogen and Alkali-Metal Atoms

This paper begins with an examination of the revival structure and long-term evolution of Rydberg wave packets for hydrogen. We show that after the initial cycle of collapse and fractional/full revivals, which occurs on the time scale $t_{\rm rev}$, a new sequence of revivals begins. We find that the structure of the new revivals is different from that of the fractional revivals. The new revivals are characterized by periodicities in the motion of the wave packet with periods that are fractions of the revival time scale $t_{\rm rev}$. These long-term periodicities result in the autocorrelation function at times greater than $t_{\rm rev}$ having a self-similar resemblance to its structure for times less than $t_{\rm rev}$. The new sequence of revivals culminates with the formation of a single wave packet that more closely resembles the initial wave packet than does the full revival at time $t_{\rm rev}$, i.e., a superrevival forms. Explicit examples of the superrevival structure for both circular and radial wave packets are given. We then study wave packets in alkali-metal atoms, which are typically used in experiments. The behavior of these packets is affected by the presence of quantum defects that modify the hydrogenic revival time scales and periodicities. Their behavior can be treated analytically using supersymmetry-based quantum-defect theory. We illustrate our results for alkali-metal atoms with explicit examples of the revival structure for radial wave packets in rubidium.Comment: To appear in Physical Review A, vol. 51, June 199

Analysis of Gene Expression in Resynthesized Brassica napus Allopolyploids Using Arabidopsis 70mer Oligo Microarrays

Background Studies in resynthesized Brassica napus allopolyploids indicate that homoeologous chromosome exchanges in advanced generations (S5:6) alter gene expression through the loss and doubling of homoeologous genes within the rearrangements. Rearrangements may also indirectly affect global gene expression if homoeologous copies of gene regulators within rearrangements have differential affects on the transcription of genes in networks. Methodology/Principal Findings We utilized Arabidopsis 70mer oligonucleotide microarrays for exploring gene expression in three resynthesized B. napus lineages at the S0:1 and S5:6 generations as well as their diploid progenitors B. rapa and B. oleracea. Differential gene expression between the progenitors and additive (midparent) expression in the allopolyploids were tested. The S5:6 lines differed in the number of genetic rearrangements, allowing us to test if the number of genes displaying nonadditive expression was related to the number of rearrangements. Estimates using per-gene and common variance ANOVA models indicated that 6–15% of 26,107 genes were differentially expressed between the progenitors. Individual allopolyploids showed nonadditive expression for 1.6–32% of all genes. Less than 0.3% of genes displayed nonadditive expression in all S0:1lines and 0.1–0.2% were nonadditive among all S5:6 lines. Differentially expressed genes in the polyploids were over-represented by genes differential between the progenitors. The total number of differentially expressed genes was correlated with the number of genetic changes in S5:6 lines under the common variance model; however, there was no relationship using a per-gene variance model, and many genes showed nonadditive expression in S0:1 lines. Conclusions/Significance Few genes reproducibly demonstrated nonadditive expression among lineages, suggesting few changes resulted from a general response to polyploidization. Furthermore, our microarray analysis did not provide strong evidence that homoeologous rearrangements were a determinant of genome-wide nonadditive gene expression. In light of the inherent limitations of the Arabidopsis microarray to measure gene expression in polyploid Brassicas, further studies are warranted

Expression of the cell death protein CED-4 of Caenorhabditis elegans in transgenic tobacco plants confers resistance to Meloidogyne incognita

Plant parasitic nematodes are devastating to agricultural production. Recent estimates indicate that losses due to nematode infestation can reach US$ 125 billion per year worldwide. Further aggravating the problem is the use of chemicals, such as methyl bromide. Even though methyl bromide is still the best tool currently available to combat nematode infestation, it has been targeted by international treaties for elimination from worldwide agriculture due to its deleterious impact on the environment. Therefore, alternatives are urgently needed to eliminate the threat of both parasitic nematodes and hazardous pesticides. In an attempt to develop novel strategies for nematode control, we produced and characterized transgenic tobacco plants constitutively expressing the ced-4 gene from Caenorhabditis elegans and exposed homozygous lines to the plant parasitic nematode Meloidogyne incognita. Five transgenic lines tested showed a significant reduction in the number of nematode-induced galls formed. These tolerant tobacco lines displayed high levels of ced-4 expression (determined via a competitive reverse transcription-PCR assay) and the presence of CED-4 (determined by Western blot analysis with anti-CED-4 antibodies). In addition, protein extracts from transgenic ced-4 plants restored CED-3 activity of the ced-4 mutant C. elegans protein extracts to wild-type levels, indicating that the CED-4 protein produced in these transgenic plants is functional. We suggest that programmed cell death genes may provide an alternative to control plant parasitic nematodes. © 2012 Korean Society for Plant Biotechnology and Springer.This work was funded by grants from the National Institute of General Medical Sciences (MBRS-SCORE grant no.: S06-GM61223), the California Agricultural Research Initiative (grant no.: ARI/CATI/Calderón-Urrea/Cell Death/03-2-006-31), and the National Institute on Minority Health and Health Disparities (NIMHD) (grant no.: Research Infrastructure for Minority Institutions P20MD002732) to A.C.-U. R.T.G was recipient of a MAI fellowship from the U.S. EPA and C.T. was recipient of a RISE fellowship from NIH (MBRS-RISE grant no.: R25 GM071423).Peer Reviewe