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The controlled production of microbial growth has the potential to reduce groundwater flow in seepage and dewatering systems. Stimulating the growth of indigenous bacteria could clog the pore space and result in a substantial permeability reduction. This study investigated the spatial distribution of permeability reduction under different nutrient stimulation treatments of indigenous bacteria across 16 cm columns of Ottawa 50-70 sand. Spatially uniform permeability reductions of up to an order of magnitude were achieved using both a high glucose (50 mg L-1) and a low glucose (10 mg L-1) nutrient formulation. The overall permeability began to drop by day 2 and generally reached a minimum permeability by day 14. There was no noticeable difference in the final permeability nor the rate of permeability reduction between high and low glucose formulations. Upscaling of experiments is highly recommended for future studies on the spatial uniformity of microbial growth and biologically induced permeability reductions. 

Can Augmented Reality (AR) immersion and interactivity dispel misconceptions and increase public understanding of science? The interdisciplinary team including USC’s Institute for Creative Technologies, the Rossier School of Education and the La Brea Tar Pits Museum, developed two AR engagements, one miniature “tabletop” and one life-sized “field” experience to investigate the differences in AR across qualitatively distinct designs on interactivity and visual immersion. Participants were able to take part in a “virtual active dig site” and discover fossils preserved in the asphalt seep; they were also able to walk amongst Mammoths in a virtual simulation of Los Angeles from 25,000 years ago. Learning goals for the experiences included: how and what types of plants and animals are entrapped in the tar pits; the similarities/differences between the LA ecosystem in the ice age vs. present; and how we use the scientific method of testing ideas with evidence and revising hypotheses. Design considerations made to evaluate the efficacy of achieving learning objectives, and engagement included: interactivity (selection and manipulation); levels of immersion (smartphone vs head-mounted display), aesthetics (high-fidelity vs low-poly 3D-models). Take-aways from pilot and formal user-studies include the ability to achieve strong interest and consistent learning with lower-fidelity AR; strong reactions to large-scale, life-sized events even with lower fidelity models; mini-experiences, large scale, and even 2D posters (control) can be engaging with the right narrative and framing. Further results from the “Pit-91” tabletop study are being analyzed and data collection on the “Field Experience” is set to investigate a life-sized experience. 

ABSTRACT The distribution of gas and metals in the circumgalactic medium (CGM) plays a critical role in how galaxies evolve. The MUSE-ALMA Haloes survey combines MUSE, ALMA, and HST observations to constrain the properties of the multiphase gas in the CGM and the galaxies associated with the gas probed in absorption. In this paper, we analyse the properties of galaxies associated with 32 strong $${\rm H\, {\small I}}$$ Ly-α absorbers at redshift 0.2 ≲ z ≲ 1.4. We detect 79 galaxies within ±500 kms−1 of the absorbers in our 19 MUSE fields. These associated galaxies are found at physical distances from 5.7 kpc and reach star formation rates as low as 0.1 M⊙ yr−1. The significant number of associated galaxies allows us to map their physical distribution on the Δv and b plane. Building on previous studies, we examine the physical and nebular properties of these associated galaxies and find the following: (i) 27/32 absorbers have galaxy counterparts and more than 50 per cent of the absorbers have two or more associated galaxies, (ii) the $${\rm H\, {\small I}}$$ column density of absorbers is anticorrelated with the impact parameter (scaled by virial radius) of the nearest galaxy as expected from simulations, (iii) the metallicity of associated galaxies is typically larger than the absorber metallicity, which decreases at larger impact parameters. It becomes clear that while strong $${\rm H\, {\small I}}$$ absorbers are typically associated with more than a single galaxy, we can use them to statistically map the gas and metal distribution in the CGM.