Cosmology in the Cosmopolis: Planetaria in the Weimar Republic

Cosmology in the Cosmopolis: Planetaria in the Weimar Republic traces the invention and subsequent popularization of the planetarium in Germany from 1923 to 1940, with particular focus on the three most celebrated planetaria in Munich, Jena, and Berlin. Literature on the history of planetaria is scant, and much of what does exist is limited to an institutional history of the invention of the planetarium projector by the Carl Zeiss Optical Company in 1923. In contrast, my dissertation contextualizes the planetarium within the urban cultural landscape of the Weimar Republic and the early years of the Third Reich. The early planetarium, I argue, encapsulated the tension between modernism and a rising conservative nostalgia for the pre-modern; on the one hand, it was a marvel of modern technology, and on the other, it was embraced as a refuge away from the city, offering a glimpse of a sky obscured by modern artificial light. My goal is thus two-fold: first, I situate my work as a critical intervention into the dominant narrative of the planetarium’s role in the history of astronomy; and second, I argue that a focus on the planetarium as a popular site of spectacle and education in the Weimar period offers a crucial perspective for understanding the relationship among cultural forms, scientific discourse, and nationalism in urban spaces. The planetarium emerges as a site in which conflicting ideas about modernity, nationalism, and the public were contested

Auto-validation of fluorescent primer extension genotyping assay using signal clustering and neural networks

BACKGROUND: SNP genotyping typically incorporates a review step to ensure that the genotype calls for a particular SNP are correct. For high-throughput genotyping, such as that provided by the GenomeLab SNPstream(® )instrument from Beckman Coulter, Inc., the manual review used for low-volume genotyping becomes a major bottleneck. The work reported here describes the application of a neural network to automate the review of results. RESULTS: We describe an approach to reviewing the quality of primer extension 2-color fluorescent reactions by clustering optical signals obtained from multiple samples and a single reaction set-up. The method evaluates the quality of the signal clusters from the genotyping results. We developed 64 scores to measure the geometry and position of the signal clusters. The expected signal distribution was represented by a distribution of a 64-component parametric vector obtained by training the two-layer neural network onto a set of 10,968 manually reviewed 2D plots containing the signal clusters. CONCLUSION: The neural network approach described in this paper may be used with results from the GenomeLab SNPstream instrument for high-throughput SNP genotyping. The overall correlation with manual revision was 0.844. The approach can be applied to a quality review of results from other high-throughput fluorescent-based biochemical assays in a high-throughput mode

Domestic chickens activate a piRNA defense against avian leukosis virus

PIWI-interacting RNAs (piRNAs) protect the germ line by targeting transposable elements (TEs) through the base-pair complementarity. We do not know how piRNAs co-evolve with TEs in chickens. Here we reported that all active TEs in the chicken germ line are targeted by piRNAs, and as TEs lose their activity, the corresponding piRNAs erode away. We observed de novo piRNA birth as host responds to a recent retroviral invasion. Avian leukosis virus (ALV) has endogenized prior to chicken domestication, remains infectious, and threatens poultry industry. Domestic fowl produce piRNAs targeting ALV from one ALV provirus that was known to render its host ALV resistant. This proviral locus does not produce piRNAs in undomesticated wild chickens. Our findings uncover rapid piRNA evolution reflecting contemporary TE activity, identify a new piRNA acquisition modality by activating a pre-existing genomic locus, and extend piRNA defense roles to include the period when endogenous retroviruses are still infectious. DOI: http://dx.doi.org/10.7554/eLife.24695.00

The discovery of endogenous retroviruses

When endogenous retroviruses (ERV) were discovered in the late 1960s, the Mendelian inheritance of retroviral genomes by their hosts was an entirely new concept. Indeed Howard M Temin's DNA provirus hypothesis enunciated in 1964 was not generally accepted, and reverse transcriptase was yet to be discovered. Nonetheless, the evidence that we accrued in the pre-molecular era has stood the test of time, and our hypothesis on ERV, which one reviewer described as 'impossible', proved to be correct. Here I recount some of the key observations in birds and mammals that led to the discovery of ERV, and comment on their evolution, cross-species dispersion, and what remains to be elucidated