5,412 research outputs found

    Incomplete Compensation and Migration Behavior: Has Anything Changed Between 1990 and 2000?

    Get PDF
    Spatial equilibrium models rely on migration to arbitrage away differences in utility across locations net of moving costs, where remaining differences in wages and rents reflect the compensating differentials related to site-specific amenities. Recent refinements to the spatial equilibrium model focus upon the prospect of disequilibrium in amenity markets. Amenity market disequilibrium implies over- or undercompensation (incomplete compensation) across some locations, which suggests a role for these factors in subsequent migration. This paper follows the theoretical and empirical approach of Clark, Herrin, Knapp, and White (2003). An intercity wage regression is estimated where fixed effects capture the impact of site characteristics on wages. We then regress the fixed effects on a comprehensive vector of site attributes, where the residuals capture incomplete compensation in wages. The derived measures of incomplete compensation are included in a binary logit model of migration. The results provide further evidence that incomplete compensation for site characteristics is a significant factor in migration decisions, and the findings are consistent with tendencies toward spatial equilibrium

    BATSE spectroscopy analysis system

    Get PDF
    The Burst and Transient Source Experiment (BATSE) Spectroscopy Analysis System (BSAS) is the software system which is the primary tool for the analysis of spectral data from BATSE. As such, Guest Investigators and the community as a whole need to know its basic properties and characteristics. Described here are the characteristics of the BATSE spectroscopy detectors and the BSAS

    Automation and robotics considerations for a lunar base

    Get PDF
    An envisioned lunar outpost shares with other NASA missions many of the same criteria that have prompted the development of intelligent automation techniques with NASA. Because of increased radiation hazards, crew surface activities will probably be even more restricted than current extravehicular activity in low Earth orbit. Crew availability for routine and repetitive tasks will be at least as limited as that envisioned for the space station, particularly in the early phases of lunar development. Certain tasks are better suited to the untiring watchfulness of computers, such as the monitoring and diagnosis of multiple complex systems, and the perception and analysis of slowly developing faults in such systems. In addition, mounting costs and constrained budgets require that human resource requirements for ground control be minimized. This paper provides a glimpse of certain lunar base tasks as seen through the lens of automation and robotic (A&R) considerations. This can allow a more efficient focusing of research and development not only in A&R, but also in those technologies that will depend on A&R in the lunar environment

    Studies of a Lacustrine-Volcanic Mars Analog Field Site with Mars-2020-like Instruments

    Get PDF
    On the upcoming Mars‐2020 rover two remote sensing instruments, Mastcam‐Z and SuperCam, and two microscopic proximity science instruments, SHERLOC and PIXL, will collect compositional (mineralogy, chemistry, and organics) data essential for paleoenvironmental reconstruction. The synergies between and limitations of these instruments were evaluated via study of a Mars analog field site in the Mojave Desert, using instruments approximating the data that will be returned by Mars‐2020. A ground truth dataset was generated for comparison to validate the results. The site consists of a succession of clay‐rich mudstones of lacustrine origin, interbedded tuffs, a carbonate‐silica travertine deposit, and gypsiferous mudstone strata. The major geological units were mapped successfully using simulated Mars‐2020 data. Simulated Mastcam‐Z data identified unit boundaries and Fe‐bearing weathering products. Simulated SuperCam passive shortwave infrared and green Raman data were essential in identifying major mineralogical composition and changes in lacustrine facies at distance; this was possible even with spectrally downsampled passive IR data. LIBS and simulated PIXL data discriminated and mapped major element chemistry. Simulated PIXL revealed mm‐scale zones enriched in zirconium, of interest for age dating. SHERLOC‐like data mapped sulfate and carbonate at sub‐mm scale; silicates were identified with increased laser pulses/spot or by averaging of hundreds of spectra. Fluorescence scans detected and mapped varied classes of organics in all samples, characterized further with follow‐on spatially targeted deep‐UV Raman spectra. Development of dedicated organics spectral libraries is needed to aid interpretation. Given these observations, the important units in the outcrop would be sampled and cached for sample return

    A population-based study of communicative participation in preschool children with speech-language impairments

    Get PDF
    Aim. To develop statistical models of preschoolers’ communicative participation development and explore variations by level of function. Methods. This was a secondary analysis of data from a longitudinal study of preschoolers with speech and language delays (N = 46,872, M age = 41.76, SD age = 11.92; 67% male) accessing publicly-funded services in Ontario Canada. Two measures were used: Focus on the Outcomes of Communication Under Six (FOCUS), measuring changes in communicative participation skills, and the Communication Function Classification System (CFCS), classifying communication function into one of five levels. We used mixed effects modeling to fit growth curves for each CFCS level. Models allowed for variation in initial FOCUS scores at 18 months, rate of growth with age, and rate of acceleration/deceleration with age. Results. Starting FOCUS score (18 months) varied inversely with CFCS level at entry to the program. Growth was initially rapid and then levelled off for children in levels I-III. Growth was less rapid for children in level IV, but levelled off, and was slow but continual for children in level V. Interpretation. This work can help us to move beyond traditional impairment-based thinking and shows that children can make meaningful communicative changes regardless of their function

    Factors Contributing to Preschoolers\u27 Communicative Participation Outcomes: Findings From a Population-Based Longitudinal Cohort Study in Ontario, Canada

    Get PDF
    Purpose. To identify predictors of communicative participation outcomes for a large cohort of preschoolers with communication disorders. Method. A secondary analysis of longitudinal program evaluation data from Ontario Canada’s Preschool Speech and Language Program (PSLP). Data available for 46,872 children 18-67 months of age (M = 41.76 mo, SD = 11.92, 68% male) were previously used to predict children’s communicative participation skill development in five levels of function. Demographic and intervention-based variables were added to the models to identify new predictors of growth. Results. Three demographic and three intervention-based variables were statistically significant predictors of children’s communicative participation outcomes. Clinically significant predictors included participation in an early learning environment, receipt of speech-language interventions, and the amount of time spent in intervention. These variables impacted predicted outcomes differently depending on a child’s level of communicative function. Conclusions. This population-based study of preschoolers with speech and language disorders identified predictors of growth in communicative participation skills – an outcome important and meaningful to families but, not often explored. A broad picture emerged of factors that may influence the development of communicative participation skills, and may be used to predict outcomes for preschoolers. Given the large sample size, these robust findings may be used to predict outcomes outside the PSLP as well
    • 

    corecore