10,364 research outputs found
Recommended from our members
Exploring the Limitations of Measures of Students` Socioeconomic Status (SES)
This study uses a nationally representative student dataset to explore the limitations of commonly used measures of socioeconomic status (SES). Among the identified limitations are patterns of missing data that conflate the traditional conceptualization of SES with differences in family structure that have emerged in recent years and a lack of theoretically-based guidance for how the components of SES should be combined. Using kindergarten achievement data, the study illustrates how both the observed relation between SES and achievement and the observed interaction between SES and kindergarten program would be impacted by the use of different measures of SES. This study also explores the measurement of SES within a structural equation modeling (SEM) framework, highlighting both the relevant conceptual and measurement issues. Accessed 9,241 times on https://pareonline.net from May 15, 2014 to December 31, 2019. For downloads from January 1, 2020 forward, please click on the PlumX Metrics link to the right
A Radio Determination of the Time of the New Moon
The detection of the New Moon at sunset is of importance to communities based
on the lunar calendar. This is traditionally undertaken with visual
observations. We propose a radio method which allows a higher visibility of the
Moon relative to the Sun and consequently gives us the ability to detect the
Moon much closer to the Sun than is the case of visual observation. We first
compare the relative brightness of the Moon and Sun over a range of possible
frequencies and find the range 5--100\,GHz to be suitable. The next
consideration is the atmospheric absorption/emission due to water vapour and
oxygen as a function of frequency. This is particularly important since the
relevant observations are near the horizon. We show that a frequency of GHz is optimal for this programme. We have designed and constructed a
telescope with a FWHM resolution of 0.6 and low sidelobes to
demonstrate the potential of this approach. At the time of the 21 May 2012 New
Moon the Sun/Moon brightness temperature ratio was in agreement
with predictions from the literature when combined with the observed sunspot
numbers for the day. The Moon would have been readily detectable at from the Sun. Our observations at 16\,hr\,36\,min UT indicated that
the Moon would have been at closest approach to the Sun 16\,hr\,25\,min
earlier; this was the annular solar eclipse of 00\,hr\,00\,min\,UT on 21 May
2012.Comment: 11 pages, 15 figures, accepted for publication in MNRA
In the Beginning... A Legacy of Computing at Marshall University
This book provides a brief history of the early computing technology at Marshall University, Huntington, W.Va., in the forty years: 1959-1999. This was before the move to Intel and Windows based servers. After installation of an IBM Accounting Machine in 1959, which arguably does not fit the modern definition of a computer, the first true computer arrived in 1963 and was installed in a room below the Registrar’s office. For the next twenty years several departments ordered their own midrange standalone systems to fit their individual departmental requirements. These represented different platforms from different vendors, and were not connected to each other. At the same time, the Marshall Computer Center developed an interconnected, multi-processor environment. With the software problems of year 2000, and the I/T move to the new Drinko Library, several systems were scrapped. New systems were installed on the pc server platforms. This book includes images of the various systems, several comments from users, and hardware and software descriptions
Evaluation of ozone difluoride as a liquid propellant additive Final report
Ozone difluoride evaluated as liquid propellant additiv
Personality factors in flight operations. Volume 1: Leader characteristics and crew performance in a full-mission air transport simulation
Crew effectiveness is a joint product of the piloting skills, attitudes, and personality characteristics of team members. As obvious as this point might seem, both traditional approaches to optimizing crew performance and more recent training development highlighting crew coordination have emphasized only the skill and attitudinal dimensions. This volume is the first in a series of papers on this simulation. A subsequent volume will focus on patterns of communication within crews. The results of a full-mission simulation research study assessing the impact of individual personality on crew performance is reported. Using a selection algorithm described in previous research, captains were classified as fitting one of three profiles along a battery of personality assessment scales. The performances of 23 crews led by captains fitting each profile were contrasted over a one-and-one-half-day simulated trip. Crews led by captains fitting a positive Instrumental-Expressive profile (high achievement motivation and interpersonal skill) were consistently effective and made fewer errors. Crews led by captains fitting a Negative Expressive profile (below average achievement motivation, negative expressive style, such as complaining) were consistently less effective and made more errors. Crews led by captains fitting a Negative Instrumental profile (high levels of competitiveness, verbal aggressiveness, and impatience and irritability) were less effective on the first day but equal to the best on the second day. These results underscore the importance of stable personality variables as predictors of team coordination and performance
CBI limits on 31 GHz excess emission in southern HII regions
We have mapped four regions of the southern Galactic plane at 31 GHz with the
Cosmic Background Imager. From the maps, we have extracted the flux densities
for six of the brightest \hii regions in the southern sky and compared them
with multi-frequency data from the literature. The fitted spectral index for
each source was found to be close to the theoretical value expected for
optically thin free-free emission, thus confirming that the majority of flux at
31 GHz is due to free-free emission from ionised gas with an electron
temperature of K.
We also found that, for all six sources, the 31 GHz flux density was slightly
higher than the predicted value from data in the literature. This excess
emission could be due to spinning dust or another emission mechanism.
Comparisons with m data indicate an average dust emissivity of
K (MJy/sr), or a 95 per cent confidence limit of K (MJy/sr). This is lower than that found in diffuse clouds at high
Galactic latitudes by a factor of . The most significant detection
() was found in (RCW49) and may account for up to
per cent of the total flux density observed at 31 GHz. Here, the
dust emissivity of the excess emission is K (MJy/sr) and
is within the range observed at high Galactic latitudes.
Low level polarised emission was observed in all six sources with
polarisation fractions in the range per cent. This is likely to be
mainly due to instrumental leakage and is therefore upper an upper limit to the
free-free polarisation. It corresponds to an upper limit of per cent
for the polarisation of anomalous emission.Comment: Accepted in MNRAS. 12 pages, 10 figures, 5 table
Recommended from our members
Construction of Mathematical Software Part II Some Examples of Mathematical Software
- …