Synthetic inversions for density using seismic and gravity data

Density variations drive mass transport in the Earth from plate tectonics to convection in the mantle and core. Nevertheless, density remains poorly known because most geophysical measurements used to probe the Earth's interior either have little sensitivity to density, suffer from trade-offs or from non-uniqueness. With the ongoing expansion of computational power, it has become possible to accurately model complete seismic wavefields in a 3-D heterogeneous Earth, and to develop waveform inversion techniques that account for complicated wavefield effects. This may help to improve resolution of density. Here, we present a pilot study where we explore the extent to which waveform inversion may be used to better recover density as a separate, independent parameter. We perform numerical simulations in 2-D to investigate under which conditions, and to what extent density anomalies may be recovered in the Earth's mantle. We conclude that density can indeed be constrained by seismic waveforms, mainly as a result of scattering effects at density contrasts. As a consequence, the low-frequency part of the wavefield is the most important for constraining the actual extent of anomalies. While the impact of density heterogeneities on the wavefield is small compared to the effects of velocity variations, it is likely to be detectable in modern regional- to global-scale measurements. We also conclude that the use of gravity data as additional information does not help to further improve the recovery of density anomalies unless strong a priori constraints on the geometry of density variations are applied. This is a result of the inherent physical non-uniqueness of potential-field inverse problems. Finally, in the limited numerical setup that we employ, we find that the initially supplied anomalies in S- and P-velocity models are of minor importance

Programmed hierarchical patterning of bacterial populations.

Modern genetic tools allow the dissection and emulation of fundamental mechanisms shaping morphogenesis in multicellular organisms. Several synthetic genetic circuits for control of multicellular patterning have been reported to date. However, hierarchical induction of gene expression domains has received little attention from synthetic biologists, despite its importance in biological self-organization. Here we report a synthetic genetic system implementing population-based AND-logic for programmed autonomous induction of bacterial gene expression domains. We develop a ratiometric assay for bacteriophage T7 RNA polymerase activity and use it to systematically characterize different intact and split enzyme variants. We then utilize the best-performing variant to build a three-color patterning system responsive to two different homoserine lactones. We validate the AND gate-like behavior of this system both in cell suspension and in surface culture. Finally, we use the synthetic circuit in a membrane-based spatial assay to demonstrate programmed hierarchical patterning of gene expression across bacterial populations

The concept of danzo : "Sandalwood images" in Japanese Buddhist sculpture of the 8th to 14th centuries.

This thesis examines Buddhist images known as danzo (sandalwood sculptures) in Japan from the 8th to 14th centuries in terms of the types of material used to make them, their distinctive form (as determined by iconography and style), and the religious functions for which they were used. All three of these fundamental defining elements are considered essential for a comprehensive understanding of danzo as religious icons, but for the clarification of crucial issues the first two chapters examine each of these elements separately. Chapters One and Two consider issues concerning definitions of materials, form according to different iconographic types and period styles, the expression of shogon (sublime adornment) and religious functions. Chapter Three provides a classification of the various types of dangan (portable sandalwood shrines). Chapters Four to Six examine the various iconographic types classified according to Nyorai, Kannon, and other Bosatsu and tutelary deities. This dissertation proposes a new definition of the form of danzo based on the distinction between the type-style and period-style, in which the expression of the aesthetic-religious concept of shogon is argued to be of central significance and danzo are considered as objects of shogon par excellence. Furthermore, textual evidence is presented to suggest that the two most common religious functions of danzo were as icons in ceremonies and for personal devotion for high-ranking monks, aristocrats, and members of the imperial family, which reflects the special sanctity ascribed to these images. The aim of this dissertation is to arrive at a more inclusive understanding of danzo as religious icons with distinctive material, formal and functional characteristics that define them as a unique group of religious icons within Japanese Buddhist sculpture

A Cyan Fluorescent Reporter Expressed from the Chloroplast Genome of Marchantia polymorpha.

Recently, the liverwort Marchantia polymorpha has received increasing attention as a basal plant model for multicellular studies. Its ease of handling, well-characterized plastome and proven protocols for biolistic plastid transformation qualify M. polymorpha as an attractive platform to study the evolution of chloroplasts during the transition from water to land. In addition, chloroplasts of M. polymorpha provide a convenient test-bed for the characterization of genetic elements involved in plastid gene expression due to the absence of mechanisms for RNA editing. While reporter genes have proven valuable to the qualitative and quantitative study of gene expression in chloroplasts, expression of green fluorescent protein (GFP) in chloroplasts of M. polymorpha has proven problematic. We report the design of a codon-optimized gfp varian, mturq2cp, which allowed successful expression of a cyan fluorescent protein under control of the tobacco psbA promoter from the chloroplast genome of M. polymorpha. We demonstrate the utility of mturq2cp in (i) early screening for transplastomic events following biolistic transformation of M. polymorpha spores; (ii) visualization of stromules as elements of plastid structure in Marchantia; and (iii) quantitative microscopy for the analysis of promoter activity