1,879 research outputs found

    Relationships between cognitive styles and written composition of African American ninth grade students in a metropolitan school district in Western Michigan /

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    The purpose of the present study was to investigate the relationships that exist between cognitive styles, and written composition. The procedure included testing 200 ninth grade students in six high schools in a metropolitan school district in western Michigan, with the Group Embedded Figures Test (GEFT). The median for the GEFT scores was the criterion used to form two categories of cognitive styles, low field-independent and high field-independent. The writing items of the Michigan Education Assessment Program (MEAP) Eighth Grade Writing Test, provided the measures for writing comprehension. Analyses of one-way ANOVA were performed to determine whether there were statistically significant differences between low field-independent and high field-independent subjects in written composition. The analysis of the data revealed a statistically significant difference for the measure of written comprehension, F (l, 198) = 214.62, P \u3c .05. The written comprehension of raw scores were higher for high field-independent subjects than for low field-independent subjects. The result of the styles were manifested in written composition. The data suggested that written comprehension is likely to differ remarkably as a function of cognitive styles. The disposition to process information in a more articulated or less articulated manner is reflected in writing

    Special Problems of the Deaf Under the Education for All Handicapped Children Act of 1975

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    With the benefit of these years of hindsight, the purpose of this Article is fourfold: (1) To explore the anticipated problems of the Act\u27s implementation and to show that several problems have been more severe than was predicted by most writers. (2) To analyze the Act\u27s basic assumption regarding placement of handicapped children as nearly as possible in a normal situationcommonly known as mainstreaming -and to show that, in many situations, that assumption has proven to be more harmful than helpful. (3) To distinguish between types of handicaps, showing how the Act-by not distinguishing between types of handicaps-produces different effects for different groups of children. (4) To explain the unique nature of deafness as a handicapping condition and to discuss the special problems of deaf children under the Act

    SUMSS: A Wide-Field Radio Imaging Survey of the Southern Sky. I. Science goals, survey design and instrumentation

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    The Molonglo Observatory Synthesis Telescope, operating at 843 MHz with a 5 square degree field of view, is carrying out a radio imaging survey of the sky south of declination -30 deg. This survey (the Sydney University Molonglo Sky Survey, or SUMSS) produces images with a resolution of 43" x 43" cosec(Dec.) and an rms noise level of about 1 mJy/beam. SUMSS is therefore similar in sensitivity and resolution to the northern NRAO VLA Sky Survey (NVSS; Condon et al. 1998). The survey is progressing at a rate of about 1000 square degrees per year, yielding individual and statistical data for many thousands of weak radio sources. This paper describes the main characteristics of the survey, and presents sample images from the first year of observation.Comment: 27 pages, 12 figures (figures 2, 8, 10 in jpg format); AJ, in pres

    Hydropyrolysis: implications for radiocarbon pre-treatment and characterization of Black Carbon

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    Charcoal is the result of natural and anthropogenic burning events, when biomass is exposed to elevated temperatures under conditions of restricted oxygen. This process produces a range of materials, collectively known as pyrogenic carbon, the most inert fraction of which is known as Black Carbon (BC). BC degrades extremely slowly, and is resistant to diagenetic alteration involving the addition of exogenous carbon making it a useful target substance for radiocarbon dating particularly of more ancient samples, where contamination issues are critical. We present results of tests using a new method for the quantification and isolation of BC, known as hydropyrolysis (hypy). Results show controlled reductive removal of non-BC organic components in charcoal samples, including lignocellulosic and humic material. The process is reproducible and rapid, making hypy a promising new approach not only for isolation of purified BC for 14C measurement but also in quantification of different labile and resistant sample C fractions

    A Terraced Scanning Superconducting Quantum Interference Device Susceptometer with Sub-Micron Pickup Loops

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    Superconducting Quantum Interference Devices (SQUIDs) can have excellent spin sensitivity depending on their magnetic flux noise, pick-up loop diameter, and distance from the sample. We report a family of scanning SQUID susceptometers with terraced tips that position the pick-up loops 300 nm from the sample. The 600 nm - 2 um pickup loops, defined by focused ion beam, are integrated into a 12-layer optical lithography process allowing flux-locked feedback, in situ background subtraction and optimized flux noise. These features enable a sensitivity of ~70 electron spins per root Hertz at 4K.Comment: See http://stanford.edu/group/moler/publications.html for an auxiliary document containing additional fabrication details and discussio

    Constriction size distributions of granular filters: a numerical study

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    The retention capability of granular filters is controlled by the narrow constrictions connecting the voids within the filter. The theoretical justification for empirical filter rules used in practice includes consideration of an idealised soil fabric in which constrictions form between co-planar combinations of spherical filter particles. This idealised fabric has not been confirmed by experimental or numerical observations of real constrictions. This paper reports the results of direct, particle-scale measurement of the constriction size distribution (CSD) within virtual samples of granular filters created using the discrete-element method (DEM). A previously proposed analytical method that predicts the full CSD using inscribed circles to estimate constriction sizes is found to poorly predict the CSD for widely graded filters due to an over-idealisation of the soil fabric. The DEM data generated are used to explore quantitatively the influence of the coefficient of uniformity, particle size distribution and relative density of the filter on the CSD. For a given relative density CSDs form a narrow band of similarly shaped curves when normalised by characteristic filter diameters. This lends support to the practical use of characteristic diameters to assess filter retention capability

    Wind measurements from an array of oceanographic moorings and from F/SMeteor during JASIN 1978

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    During the Joint Air-Sea Interaction (JASIN) experiment conducted in the northern Rockall Trough in the summer of 1978, oceanographic moorings with surface buoys carrying wind recorders were deployed in an array designed to investigate the variability of the near-surface wind field at scales of from 2 to 200 km. The wind records together with observations taken on board the research vessels participating in JASIN have provided ground truth measurements for the sea surface wind velocity sensors on the Seasat satellite. During most of the experiment the wind field was characterized by spatial scales large in comparison with the separations between the buoys. On several occasions, spatial differences associated with cold fronts were identified, and it was possible to track the passage of the front through the array. However, quantitative analysis of the variability of the wind field was complicated both by a lack of data due to mechanical failures of some instruments and by significant differences in the performance of the diverse types of wind recorders. Reevaluation of the instruments used in JASIN and recent comparison of some of these instruments with more conventional sets of wind sensors confirm the possibility that there is significant error in the JASIN wind measurements made from the buoys. In particular, the vector-averaging wind recorder on W2, which was one of the few instruments to recover a full length record and which was chosen during a Seasat-JASIN workshop as the JASIN standard, had performance characteristics that were among the most difficult to explain
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