18 research outputs found
Sociology, Applied Work, and Experimental Learning
Experiential learning settings (internships, practice, field placements) are no longer an educational experiment. They are found in secondary schools, colleges, and universities and are well established within departments of sociology (Satariano and Rogers, 1979). Furthermore, we can anticipate their expanded use in the future. Bradshaw and McPherron (1978) report in a national survey of undergraduate curricula that community college, four-year college, and university departments of sociology all expect to increase their use of field experience more than any other teaching technique
DeMartini, Joseph R. and Les B. Whitbeck, Knowledge Use as Knowledge Creation, Knowledge: Creation, Diffusion, Utilization, 7(June, 1986), 383-396.
Describes how knowledge was used in situations as a form of knowledge creation
Sharks and jacks in the Northwestern Hawaiian Islands from towed-diver surveys 2000 - 2003
Volume: 543Start Page: 257End Page: 27
Effects of kynurenic acid analogue 1 (KYNA-A1) in nitroglycerin-induced hyperalgesia: Targets and anti-migraine mechanisms
Direct N-body Simulations of Satellite Formation around Small Asteroids: Insights from DARTâs Encounter with the Didymos System
We explore binary asteroid formation by spin-up and rotational disruption considering the NASA DART mission's encounter with the DidymosâDimorphos binary, which was the first small binary visited by a spacecraft. Using a suite of N -body simulations, we follow the gravitational accumulation of a satellite from meter-sized particles following a mass-shedding event from a rapidly rotating primary. The satelliteâs formation is chaotic, as it undergoes a series of collisions, mergers, and close gravitational encounters with other moonlets, leading to a wide range of outcomes in terms of the satellite's mass, shape, orbit, and rotation state. We find that a Dimorphos-like satellite can form rapidly, in a matter of days, following a realistic mass-shedding event in which only âŒ2%â3% of the primary's mass is shed. Satellites can form in synchronous rotation due to their formation near the Roche limit. There is a strong preference for forming prolate (elongated) satellites, although some simulations result in oblate spheroids like Dimorphos. The distribution of simulated secondary shapes is broadly consistent with other binary systems measured through radar or lightcurves. Unless Dimorphos's shape is an outlier, and considering the observational bias against lightcurve-based determination of secondary elongations for oblate bodies, we suggest there could be a significant population of oblate secondaries. If these satellites initially form with elongated shapes, a yet-unidentified pathway is needed to explain how they become oblate. Finally, we show that this chaotic formation pathway occasionally forms asteroid pairs and stable triples, including coorbital satellites and satellites in mean-motion resonances
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Near-zero cohesion and loose packing of Bennuâs near subsurface revealed by spacecraft contact
When the OSIRIS-REx spacecraft pressed its sample collection mechanism into the surface of Bennu, it provided a direct test of the poorly understood near-subsurface physical properties of rubble-pile asteroids, which consist of rock fragments at rest in microgravity. Here, we find that the forces measured by the spacecraft are best modeled as a granular bed with near-zero cohesion that is half as dense as the bulk asteroid. The low gravity of a small rubble-pile asteroid such as Bennu effectively weakens its near subsurface by not compressing the upper layers, thereby minimizing the influence of interparticle cohesion on surface geology. The underdensity and weak near subsurface should be global properties of Bennu and not localized to the contact point