Whitman and Van Gogh: Starry Nights and Other Similarities

Explores the similarities between Whitman\u27s poetry and Van Gogh\u27s painting "Starry Night," with a particular emphasis on their similar use of "star imagery.

Alpha/beta and gamma interferons are induced by infection with noncytopathic bovine viral diarrhea virus in vivo

In contrast to the results of previous in vitro studies, experimental infection of calves with noncytopathic bovine viral diarrhea virus (ncpBVDV) was found to induce strong alpha/beta and gamma interferon responses in gnotobiotic animals. These responses were associated with depressed levels of transforming growth factor β (TGF-β) in serum. The results of this study indicate that the immunosuppression caused by ncpBVDV is not associated with low interferon responses or elevated levels of TGF-β

Pulse retrieval and soliton formation in a non-standard scheme for dynamic electromagnetically induced transparency

We examine in detail an alternative method of retrieving the information written into an atomic ensemble of three-level atoms using electromagnetically induced transparency. We find that the behavior of the retrieved pulse is strongly influenced by the relative collective atom-light coupling strengths of the two relevant transitions. When the collective atom-light coupling strength for the retrieval beam is the stronger of the two transitions, regeneration of the stored pulse is possible. Otherwise, we show the retrieval process can lead to creation of soliton-like pulses.Comment: 11 figure

A compendium of Caenorhabditis elegans regulatory transcription factors: a resource for mapping transcription regulatory networks

Background Transcription regulatory networks are composed of interactions between transcription factors and their target genes. Whereas unicellular networks have been studied extensively, metazoan transcription regulatory networks remain largely unexplored. Caenorhabditis elegans provides a powerful model to study such metazoan networks because its genome is completely sequenced and many functional genomic tools are available. While C. elegans gene predictions have undergone continuous refinement, this is not true for the annotation of functional transcription factors. The comprehensive identification of transcription factors is essential for the systematic mapping of transcription regulatory networks because it enables the creation of physical transcription factor resources that can be used in assays to map interactions between transcription factors and their target genes. Results By computational searches and extensive manual curation, we have identified a compendium of 934 transcription factor genes (referred to as wTF2.0). We find that manual curation drastically reduces the number of both false positive and false negative transcription factor predictions. We discuss how transcription factor splice variants and dimer formation may affect the total number of functional transcription factors. In contrast to mouse transcription factor genes, we find that C. elegans transcription factor genes do not undergo significantly more splicing than other genes. This difference may contribute to differences in organism complexity. We identify candidate redundant worm transcription factor genes and orthologous worm and human transcription factor pairs. Finally, we discuss how wTF2.0 can be used together with physical transcription factor clone resources to facilitate the systematic mapping of C. elegans transcription regulatory networks. Conclusion wTF2.0 provides a starting point to decipher the transcription regulatory networks that control metazoan development and function

Fast gates for ion traps by splitting laser pulses

We present a fast phase gate scheme that is experimentally achievable and has an operation time more than two orders of magnitude faster than current experimental schemes for low numbers of pulses. The gate time improves with the number of pulses following an inverse power law. Unlike implemented schemes which excite precise motional sidebands, thus limiting the gate timescale, our scheme excites multiple motional states using discrete ultra-fast pulses.We use beam-splitters to divide pulses into smaller components to overcome limitations due to the finite laser pulse repetition rate. This provides gate times faster than proposed theoretical schemes when we optimize a practical setup

Quantum depletion of collapsing Bose-Einstein condensates

We perform the first numerical three-dimensional studies of quantum field effects in the Bosenova experiment on collapsing condensates by E. Donley et al. [Nature 415, 39 (2002)] using the exact experimental geometry. In a stochastic truncated Wigner simulation of the collapse, the collapse times are larger than the experimentally measured values. We find that a finite temperature initial state leads to an increased creation rate of uncondensed atoms, but not to a reduction of the collapse time. A comparison of the time-dependent Hartree-Fock-Bogoliubov and Wigner methods for the more tractable spherical trap shows excellent agreement between the uncondensed populations. We conclude that the discrepancy between the experimental and theoretical values of the collapse time cannot be explained by Gaussian quantum fluctuations or finite temperature effects.Comment: 9 pages, 4 figures, replaced with published versio

Smallholder Participation in Agricultural Value Chains: Comparative Evidence from Three Continents

Supermarkets, specialized wholesalers, and processors and agro-exporters’ agricultural value chains have begun to transform the marketing channels into which smallholder farmers sell produce in low-income economies. We develop a conceptual framework through which to study contracting between smallholders and a commodity-processing firm. We then conduct an empirical meta-analysis of agricultural value chains in five countries across three continents (Ghana, India, Madagascar, Mozambique, and Nicaragua). We document patterns of participation, the welfare gains associated with participation, reasons for non-participation, the significant extent of contract non-compliance, and the considerable dynamism of these value chains, as farmers and firms enter and exit frequently.