San Francisco State University

About: San Francisco State University is a education organization based out in San Francisco, California, United States. It is known for research contribution in the topics: Population & Planet. The organization has 5669 authors who have published 11433 publications receiving 408075 citations. The organization is also known as: San Francisco State & San Francisco State Normal School.

A new model for Mars atmospheric dust based upon analysis of ultraviolet through infrared observations from Mariner 9, Viking, and Phobos

Abstract: We propose key modifications to the Toon et al. (1977) model of the particle size distribution and composition of Mars atmospheric dust, based on a variety of spacecraft and wavelength observations of the dust. A much broader (r(sub eff) variance approximately 0.8 micrometers), smaller particle size (r(sub mode) approximately 0.02 micrometers) distribution coupled with a 'palagonite-like' composition is argued to fit the complete ultraviolet-to-30-micrometer absorption properties of the dust better than the montmorillonite-basalt, r(sub eff) variance = 0.4 micrometers, r(sub mode) = 0.40 dust model of Toon et al. Mariner 9 (infrared interferometer spectrometer) IRIS spectra of high atmospheric dust opacities during the 1971-1972 Mars global dust storm are analyzed in terms of the Toon et al. dust model, and a Hawaiian palagonite sample (Rousch et al., 1991) with two different size distribution models incorporating smaller dust particle sizes. Viking Infrared Thermal Mapper (IRTM) emmission-phase-function (EPF) observations at 9 micrometers are analyzed to retrieve 9-micrometer dust opacities coincident with solar band dust opacities obtained from the same EPF sequences (Clancy and Lee, 1991). These EPF dust opacities provide an independent measurement of the visible/9-micrometer extinction opacity ratio (greater than or = 2) for Mars atmospheric dust, which is consistent with a previous measurement by Martin (1986). Model values for the visible/9-micrometer opacity ratio and the ultraviolet and visible single-scattering albedos are calculated for the palagonite model with the smaller particle size distributions compared to the same properties for the Toon et al. model of dust. The montmorillonite model of the dust is found to fit the detailed shape of the dust 9-micrometer absorption well. However, it predicts structured, deep aborptions at 20 micrometers which are not observed and requires a separate ultraviolet-visible absorbing component to match the observed behavior of the dust in this wavelength region. The modeled palagonite does not match the 8-to 9-micrometer absorption presented by the dust in the IRIS spectra, probably due to its low SiO2 content (31%). However, it does provide consistent levels of ultraviolet/visible absorption, 9-to 12-micrometer absorption, and a lack of structured absorption at 20 micrometers. The ratios of dust extinction opacities at visible, 9 micrometers, and 30 micrometers are strongly affected by the dust particle size distribution. The Toon et al. dust size distribution (r(sub mode) = 0.40,r(sub eff) variance = 0.4 micrometers, r(sub cwmu) = 2.7 micrometers) predicts the correct ratio of the 9- to 30-micrometer opacity, but underpredicts the visible/9-micrometer opacity ratio considerably (1 versus greater than or = 2). A similar particle distribution width with smaller particle sizes (r(sub mode) = 0.17, r(sub eff) variance = 0.4 micrometers, r(sub cwmu) = 1.2 micrometers) will fit the observed visible/9-micrometer opacity ratio, but overpredicts the observed 9-micrometer/30-micrometer opacity ratio. A smaller and much broader particle size distribution (r(sub mode) = 0.002, r(sub eff) variance = 0.8 micrometers, r(sub cwmu) = 1.8 micrometers) can fit both dust opacity ratios. Overall, the nanocrystalline structure of palagonite coupled with a smaller, broader distribution of dust particle sizes provides a more consistent fit than the Toon et al. model of the dust to the IRIS spectra, the observed visible/9-micrometer dust opacity ratio, the Phobos occulation measurements of the dust particle sizes (Chassefiere et al., 1992), and the weakness of surface near IR absorptions expected for clay minerals (Clark, 1992; Bell and Crisp, 1993).

Context-Specific Measurement of Individualism-Collectivism on the Individual Level The Individualism-Collectivism Interpersonal Assessment Inventory

Abstract: Cross-cultural research would be greatly aided by the availability of psychometrically sound measures of meaningful cultural dimensions of variability on the individual level. We report six studies that establish the validity and reliability of an individual-based assessment inventory of individualistic versus collectivistic tendencies in four social relationships (the Individualism-Collectivism Interpersonal Assessment Inventory-ICIAI). The results of the first five studies provide strong evidence for the reliability and validity of the ICIAI. The sixth study, including data from four different countries and four different ethnic groups within the United States, demonstrate the utility of the ICIAI to map cultural differences in multiple contexts and rating domains.

Plasmonic Airy beams with dynamically controlled trajectories

Abstract: We report the experimental generation and dynamic trajectory control of plasmonic Airy beams (PABs). The PABs are created by directly coupling free-space Airy beams to surface plasmon polaritons through a grating coupler on a metal surface. We show that the ballistic motion of the PABs can be reconfigured in real time by either a computer addressed spatial light modulator or mechanical means.

The use of overgeneralization and transfer learning strategies by elementary and intermediate students of esl1

Abstract: An orally administered test requiring the written English translation of eighty Spanish sentences was administered to twenty native Spanish speaking students of English as a second language at the elementary and intermediate levels. A taxonomy of twenty error types was designed to analyze the errors in the Auxiliary (Aux) and Verb Phrase (VP) of the translations. The error types were categorized into errors of overgeneralization, transfer, translation, indeterminate origin, and errors not considered. The results indicated that the errors made by the elementary and intermediate students were not qualitatively different. However, the subjects' reliance on the stategies of overgeneralization and transfer was found to be qualitatively different. The elementary subjects' reliance on the transfer strategy was found to be significantly higher than that of the intermediate subjects; the intermediate subjects' reliance on the overgeneralization stategy was found to be significantly higher than that of the elementary subjects. These findings appear to be consistent with a theory which considers second language acquisition to be an actively creative process dependent upon a student's ability to assimilate and subsume new information into already existing cognitive structures. The overgeneralization and transfer learning strategies appear to be two distinctly different linguistic manifestations of one psychological process: reliance on prior learning to facilitate new learning. The results also tend to confirm the weakness of a transfer-based theory of errors and require an explanation which takes into account not only interference from within the target language inself, but also the learner's cognitive characteristics and his resulting learning strategies.

Weak Measurements vs. Strong Statistics: An Empirical Critique of S. S. Stevens' Proscriptions nn Statistics

Abstract: those who belong to what might be called the school of &dquo;strong statistics&dquo; has persisted for a number of years with little apparent change of attitude on either side. Stevens, as the leading spokesman for the weak measurement school, has asserted (1951) and reasserted (1959, 1960) the view that measurement scales are models of object relationships and, for the most part, rather poor models which can lead one far astray from the truth if the scores they yield are added when they should only be counted. At least two current statistics texts intended for psychologists (Senders, 1958; Siegel, 1956) present this view as gospel. Opposing this view, an assortment of statistically minded psycholo gists-e.g., Lord (1953), Burke (1953), Anderson (1961),