62 research outputs found
The dynamic geophysical environment of (101955) Bennu based on OSIRIS-REx measurements
The top-shaped morphology characteristic of asteroid (101955) Bennu, often found among fast-spinning asteroids and binary asteroid primaries, may have contributed substantially to binary asteroid formation. Yet a detailed geophysical analysis of this morphology for a fast-spinning asteroid has not been possible prior to the Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer (OSIRIS-REx) mission. Combining the measured Bennu mass and shape obtained during the Preliminary Survey phase of the OSIRIS-REx mission, we find a notable transition in Bennuâs surface slopes within its rotational Roche lobe, defined as the region where material is energetically trapped to the surface. As the intersection of the rotational Roche lobe with Bennuâs surface has been most recently migrating towards its equator (given Bennuâs increasing spin rate), we infer that Bennuâs surface slopes have been changing across its surface within the last million years. We also find evidence for substantial density heterogeneity within this body, suggesting that its interior is a mixture of voids and boulders. The presence of such heterogeneity and Bennuâs top shape are consistent with spin-induced failure at some point in its past, although the manner of its failure cannot yet be determined. Future measurements by the OSIRIS-REx spacecraft will provide insight into and may resolve questions regarding the formation and evolution of Bennuâs top-shape morphology and its link to the formation of binary asteroids
Evidence for widespread hydrated minerals on asteroid (101955) Bennu
Early spectral data from the Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer (OSIRIS-REx) mission reveal evidence for abundant hydrated minerals on the surface of near-Earth asteroid (101955) Bennu in the form of a near-infrared absorption near 2.7â”m and thermal infrared spectral features that are most similar to those of aqueously altered CM-type carbonaceous chondrites. We observe these spectral features across the surface of Bennu, and there is no evidence of substantial rotational variability at the spatial scales of tens to hundreds of metres observed to date. In the visible and near-infrared (0.4 to 2.4â”m) Bennuâs spectrum appears featureless and with a blue (negative) slope, confirming previous ground-based observations. Bennu may represent a class of objects that could have brought volatiles and organic chemistry to Earth
Photoleucine Survives Backbone Cleavage by Electron Transfer Dissociation. A Near-UV Photodissociation and Infrared Multiphoton Dissociation Action Spectroscopy Study
Codependence and conduct disorder: Feminine versus masculine coping responses to abusive parenting practices
This study supported the hypothesis that codependence reflects a stereotypically feminine coping strategy to environmental stressors, while conduct disorder represents an alternate coping response reflecting stereotypically masculine behaviors. High school students ( N = 218; 81% Anglo-American, 8% Asian-American, 5% Hispanic-American) completed measures of femininity/masculinity, codependence, conduct disorder, and unhealthy parenting practices. Multiple regression analyses revealed that codependence is related to parental abuse and femininity ( R = .50). A marginal relationship between codependence and parental alcoholism was mediated by parental abuse, calling into question the validity of the codependence construct. Conduct disorder was related to parental abuse, masculinity, parental alcoholism, and gender ( R = .62). The tendency to label stereotypically feminine coping strategies as pathological, while ignoring a more prevalent and destructive masculine coping strategy is discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45612/1/11199_2005_Article_BF01548255.pd
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