Overview of office of space transportation systems future planning

The Space Transportation Systems' key milestones as well as the future planning of the Office of Space Transportation Systems are summarized. A brief description and identification of candidate new starts with target development initiation and first flight dates are included

Reconstructing somatic evolutionary dynamics in solid human tissues using spatial genomic data

Spatial architecture in biological systems, such as human tissues, plays a crucial role in how they evolve and function over time. Despite longitudinal sampling in humans often being infeasible, inhibiting direct measurement of past evolution, earlier dynamics leave a footprint on the spatial arrangement of cells. The link between evolution and the resulting spatial architecture remains largely unknown, however, yet understanding this relationship could help to elucidate past tissue dynamics, including early cancer evolution. In this thesis, we explore the spatial signatures of somatic evolution in normal and cancerous human tissues, investigating how to utilise spatial patterns of DNA mutations to study past evolution. We introduce two new methodologies for spatial analysis of tumour tissue, exploiting random walk theory and fractal geometry to quantify patterns of tumour sub-population mixing. Combining analysis of experimentally measured colorectal cancer with spatial agent-based modelling, we establish frameworks to quantify the replicative advantage, time of emergence, and pushing strength of tumour sub-populations from single time-point samples. In doing so we demonstrate that high resolution spatial patterns of sub-population mixing in tumours can provide insights into early cancer dynamics. Second, we apply the same computational model to investigate regenerative dynamics within normal human liver, using spatial patterns of DNA mutations to show that long-lived progenitor cells, situated near the portal veins, drive punctuated expansions of liver cells. We provide new insights into normal liver dynamics in humans and establish a foundation for understanding how they may be modulated in diseased liver. Together, the results in this thesis demonstrate the knowledge which can be gained by leveraging the spatial context of cells, and provide a baseline for future spatial analyses of solid tissue

Species Richness Increased Yield Stability in Intensively Managed Grasslands Subjected to Experimental Drought

Climate change is expected to cause an increase in the frequency and intensity of drought events. Over two years we investigated the effects of experimentally imposed drought on intensively managed grassland communities (5 m x 6 m plots) of varying richness (1, 2 and 4 species), and comprising four species (Lolium perenne L., Cichorium intybus L., Trifolium repens L., Trifolium pratense L.). In each year a summer drought period of nine weeks with complete exclusion of precipitation was simulated, inducing severe drought stress at Reckenholz (Zürich, Switzerland), and extreme drought stress at Wexford (Ireland). Mean yield and plot-to-plot variance of yield were measured across harvests during drought and after a subsequent post-drought recovery period. At both sites, there was a positive relationship between species richness and yield under both the rainfed control conditions and under drought. At both sites, four-species communities had lower plot-to-plot variance of yield compared to monoculture or two-species communities under both rainfed (-49% smaller standard deviation) and drought conditions (-24%), which demonstrates higher yield stability in four-species communities. At the Swiss but not the Irish site, a high degree of species asynchrony could be identified as a mechanism underlying increased temporal stability in four-species communities

Hybrid GaN microLED platform for fluorescence sensing

A hybrid GaN μLED platform developed for wearable illumination is adapted here for fluorescence sensing. Proof-of-principle detection of colloidal quantum dots down to 80 pM using a mobile phone camera is demonstrate