Multi-spectral and thermal scanner experiments along the Massachusetts coastline Final report

Aerial multispectral and infrared scanning of Massachusetts coastlin

Strategies and challenges to facilitate situated learning in virtual worlds post-Second Life

Virtual worlds can establish a stimulating environment to support a situated learning approach in which students simulate a task within a safe environment. While in previous years Second Life played a major role in providing such a virtual environment, there are now more and more alternative—often OpenSim-based—solutions deployed within the educational community. By drawing parallels to social networks, we discuss two aspects: how to link individually hosted virtual worlds together in order to implement context for immersion and how to identify and avoid “fake” avatars so people behind these avatars can be held accountable for their actions

Technology requirements for future Earth-to-geosynchronous orbit transportation systems. Volume 1: Executive summary

Technologies including accelerated technology that are critical to performance and/or provide cost advantages for future space transportation systems are identified. Mission models are scoped and include priority missions, and cargo missions. Summary data, providing primary design concepts and features, are given for the SSTO, HLLV, POTV, and LCOTV vehicles. Significant system costs and total system costs in terms of life cycle costs in both discounted and undiscounted dollars are summarized for each of the vehicles

Technology requirements for future Earth-to-geosynchronous orbit transportation systems. Volume 3: Appendices

Technological requirements and forecasts of rocket engine parameters and launch vehicles for future Earth to geosynchronous orbit transportation systems are presented. The parametric performance, weight, and envelope data for the LOX/CH4, fuel cooled, staged combustion cycle and the hydrogen cooled, expander bleed cycle engine concepts are discussed. The costing methodology and ground rules used to develop the engine study are summarized. The weight estimating methodology for winged launched vehicles is described and summary data, used to evaluate and compare weight data for dedicated and integrated O2/H2 subsystems for the SSTO, HLLV and POTV are presented. Detail weights, comparisons, and weight scaling equations are provided

Mathematical modeling of genome replication

Peer reviewedPublisher PD

Bacteria Use Type IV Pili to Walk Upright and Detach from Surfaces

1. Department of Bioengineering, California Nano Systems Institute,University of California, Los Angeles, CA 90024, USA. 2. Department of Chemical and Biomolecular Engineering, University of Houston, Houston, TX 77204, USA. 3. Department of Materials Science and Engineering, University of Illinois, Urbana-Champaign, IL 61801, USA. 4. Department of Civil Engineering and Geological Sciences, University of Notre Dame, Notre Dame, IN 46556, USA.Bacterial biofilms are structured multicellular communities involved in a broad range of infections. Knowing how free-swimming bacteria adapt their motility mechanisms near surfaces is crucial for understanding the transition between planktonic and biofilm phenotypes. By translating microscopy movies into searchable databases of bacterial behavior, we identified fundamental type IV pili–driven mechanisms for Pseudomonas aeruginosa surface motility involved in distinct foraging strategies. Bacteria stood upright and “walked” with trajectories optimized for two-dimensional surface exploration. Vertical orientation facilitated surface detachment and could influence biofilm morphology.Center for Nonlinear Dynamic

The differential response of kelp to swell and infragravity wave motion

We present field measurements of the movement of the giant kelp Macrocystis pyrifera under wave forcing. We resolve the depth and frequency-dependent responses along the stipe and find different and counterintuitive patterns of response at the infragravity and swell wave forcing frequencies. At swell frequencies, tilting of the stipe is largest toward the holdfast, whereas at infragravity frequencies, the stipe tilting is largest closer to the water surface. It is postulated that the stretching of blades and subsequent pull on the stipe is, in part, responsible for these patterns. This conclusion is supported by results of manipulative experiments, which show a more along-stipe uniform response after removal of blades from the kelp. The length of the kelp also exerts a strong control on the relative magnitudes of movements in the different frequency bands, with the swell band becoming more important relative to the infragravity band for shorter length kelp. These results indicate that kelp will differentially dissipate energy over both frequencies and varying depths within the water column. The variety of movement responses over differing wave forcing frequencies may also imply that there exist differing rates of breakage for kelp exposed to hydrodynamics stressors of multiple frequencies