MISR stereoscopic image matchers: techniques and results

The Multi-angle Imaging SpectroRadiometer (MISR) instrument, launched in December 1999 on the NASA EOS Terra satellite, produces images in the red band at 275-m resolution, over a swath width of 360 km, for the nine camera angles 70.5/spl deg/, 60/spl deg/, 45.6/spl deg/, and 26.1/spl deg/ forward, nadir, and 26.1/spl deg/, 45.6/spl deg/, 60/spl deg/, and 70.5/spl deg/ aft. A set of accurate and fast algorithms was developed for automated stereo matching of cloud features to obtain cloud-top height and motion over the nominal six-year lifetime of the mission. Accuracy and speed requirements necessitated the use of a combination of area-based and feature-based stereo-matchers with only pixel-level acuity. Feature-based techniques are used for cloud motion retrieval with the off-nadir MISR camera views, and the motion is then used to provide a correction to the disparities used to measure cloud-top heights which are derived from the innermost three cameras. Intercomparison with a previously developed "superstereo" matcher shows that the results are very comparable in accuracy with much greater coverage and at ten times the speed. Intercomparison of feature-based and area-based techniques shows that the feature-based techniques are comparable in accuracy at a factor of eight times the speed. An assessment of the accuracy of the area-based matcher for cloud-free scenes demonstrates the accuracy and completeness of the stereo-matcher. This trade-off has resulted in the loss of a reliable quality metric to predict accuracy and a slightly high blunder rate. Examples are shown of the application of the MISR stereo-matchers on several difficult scenes which demonstrate the efficacy of the matching approach

Providing Outreach and Enrollment Assistance: Lessons Learned from Community Health Centers in Massachusetts

Six years ago, Massachusetts implemented a broad expansion of health coverage to the uninsured population in the state. Understanding that outreach and enrollment assistance would be essential to the success of the expansion, state policymakers provided for public education campaigns, but also for person-to-person, hands-on assistance, especially in communities with large numbers of uninsured people. Community health centers play a central role in this effort. As states and communities gear up to provide outreach and enrollment assistance under the ACA, the experience of the Massachusetts health centers offers lessons that can help inform current efforts to reach and enroll millions of low-income, uninsured Americans in health insurance. Recent interviews conducted with a sample of Massachusetts health centers point to four key findings: Finding #1: Intensive outreach and enrollment assistance is crucial to connect low-income, uninsured people with coverage. Finding #2: Assistance is not a one-time matter – it is needed at all stages of the enrollment process and to ensure continued coverage. Finding #3: Immediate access to enrollment assistance boosts the effectiveness of outreach efforts. Finding #4: Even when health reform is mature, the need for aggressive outreach and enrollment assistance remains high and the resource demands remain significant. The Massachusetts health center experience demonstrates that, in addition to broad public education about affordable insurance options and how to enroll, intensive one-on-one assistance is a vital complement to help disadvantaged populations and communities obtain and keep coverage that meets their needs. The intensive support they require, and ongoing rather than occasional needs for assistance, suggest the importance of sustained investment in outreach and enrollment efforts conducted by health centers and other organizations

Student Outcomes from the Collective Design and Delivery of Culturally Relevant Engineering Outreach Curricula in Rural and Appalachian Middle Schools

Middle school is a pivotal time for career choice, and research is rich with studies on how students perceive engineering, as well as corresponding intervention strategies to introduce younger students to engineering and inform their conceptions of engineering. Unfortunately, such interventions are typically not designed in culturally relevant ways. Consequently, there continues to be a lack of students entering engineering and a low level of diverse candidates for this profession. The purpose of this study was to explore how students in rural and Appalachian Virginia conceive of engineering before and after engagement with culturally relevant hands-on activities in the classroom. We used student responses to the Draw an Engineer Test (DAET), consisting of a drawing and several open-ended prompts administered before and after the set of engagements, to answer our research questions related to changes in students’ conceptions of engineering. We used this study to develop recommendations for teachers for the use of such engineering engagement practices and how to best assess their outcomes, including looking at the practicality of the DAET. Overall, we found evidence that our classroom engagements positively influenced students’ conceptions of engineering in these settings

Explaining Polarization Reversals in STEREO Wave Data

Recently Breneman et al. reported observations of large amplitude lightning and transmitter whistler mode waves from two STEREO passes through the inner radiation belt (L<2). Hodograms of the electric field in the plane transverse to the magnetic field showed that the transmitter waves underwent periodic polarization reversals. Specifically, their polarization would cycle through a pattern of right-hand to linear to left-hand polarization at a rate of roughly 200 Hz. The lightning whistlers were observed to be left-hand polarized at frequencies greater than the lower hybrid frequency and less than the transmitter frequency (21.4 kHz) and right-hand polarized otherwise. Only righthand polarized waves in the inner radiation belt should exist in the frequency range of the whistler mode and these reversals were not explained in the previous paper. We show, with a combination of observations and simulated wave superposition, that these polarization reversals are due to the beating of an incident electromagnetic whistler mode wave at 21.4 kHz and linearly polarized, symmetric lower hybrid sidebands Doppler-shifted from the incident wave by +/-200 Hz. The existence of the lower hybrid waves is consistent with the parametric decay mechanism of Lee and Kuo whereby an incident whistler mode wave decays into symmetric, short wavelength lower hybrid waves and a purely growing (zero-frequency) mode. Like the lower hybrid waves, the purely growing mode is Doppler-shifted by 200 Hz as observed on STEREO. This decay mechanism in the upper ionosphere has been previously reported at equatorial latitudes and is thought to have a direct connection with explosive spread F enhancements. As such it may represent another dissipation mechanism of VLF wave energy in the ionosphere and may help to explain a deficit of observed lightning and transmitter energy in the inner radiation belts as reported by Starks et al

Beetle (Coleoptera: Scirtidae) Facilitation of Larval Mosquito Growth in Tree Hole Habitats is Linked to Multitrophic Microbial Interactions

Container-breeding mosquitoes, such as Aedes triseriatus, ingest biofilms and filter water column microorganisms directly to obtain the bulk of their nutrition. Scirtid beetles often co-occur with A. triseriatus and may facilitate the production of mosquito adults under low-resource conditions. Using molecular genetic techniques and quantitative assays, we observed changes in the dynamics and composition of bacterial and fungal communities present on leaf detritus and in the water column when scirtid beetles co-occur with A. triseriatus. Data from terminal restriction fragment polymorphism analysis indicated scirtid presence alters the structure of fungal communities in the water column but not leaf-associated fungal communities. Similar changes in leaf and water bacterial communities occurred in response to mosquito presence. In addition, we observed increased processing of leaf detritus, higher leaf-associated enzyme activity, higher bacterial productivity, and higher leaf-associated fungal biomass when scirtid beetles were present. Such shifts suggest beetle feeding facilitates mosquito production indirectly through the microbial community rather than directly through an increase in available fine particulate organic matter

Ictus: A User-Centered System of Score Study for Semi-Novice Conductors

Ictus supports the study and preparation of musical scores by semi-novice conductors. It does so by representing the complex analytical processes in which professional conductors routinely engage. Through iterative design and prototyping and with feedback from expert conductors, we have developed a prototyped system for use as a learning tool. This paper presents a brief overview of the complexities of the conductor's task, including the difficulties inherent in externalizing it; a description of the Ictus system; and a discussion of some of the feedback and forward-looking issues that have been raised

The effects of social density, spatial density, noise, and office views on perceived personal space in the virtual workplace

Here we sought to understand how perceived personal space is influenced by a number of variables that could influence Indoor Environmental Quality (IEQ); specifically, we tested how different levels of social density, spatial density, noise presence, and type of view impact the appreciation of personal space in a shared office environment. We employed virtual reality (VR) to simulate shared and single occupancy offices and devised a novel measure of personal space estimation. We also used a traditional personal space satisfaction score. Participants experienced greater perceived personal space when (1) in a sparsely populated rather than a dense office, (2) in a private office rather than an open plan office, and (3) having any view outside of the office. We did not find an effect of the presence of noise or increased social density (with spatial density held constant) on the perception of personal space

Food-web structure in relation to environmental gradients and predator-prey ratios in tank-bromeliad ecosystems

Little is known of how linkage patterns between species change along environmental gradients. The small, spatially discrete food webs inhabiting tank-bromeliads provide an excellent opportunity to analyse patterns of community diversity and food-web topology (connectance, linkage density, nestedness) in relation to key environmental variables (habitat size, detrital resource, incident radiation) and predators: prey ratios. We sampled 365 bromeliads in a wide range of understorey environments in French Guiana and used gut contents of invertebrates to draw the corresponding 365 connectance webs. At the bromeliad scale, habitat size (water volume) determined the number of species that constitute food-web nodes, the proportion of predators, and food-web topology. The number of species as well as the proportion of predators within bromeliads declined from open to forested habitats, where the volume of water collected by bromeliads was generally lower because of rainfall interception by the canopy. A core group of microorganisms and generalist detritivores remained relatively constant across environments. This suggests that (i) a highly-connected core ensures food-web stability and key ecosystem functions across environments, and (ii) larger deviations in food-web structures can be expected following disturbance if detritivores share traits that determine responses to environmental changes. While linkage density and nestedness were lower in bromeliads in the forest than in open areas, experiments are needed to confirm a trend for lower food-web stability in the understorey of primary forests