4,262 research outputs found
Pupil mobility, attainment and progress in secondary school
This paper is the second of two articles arising from a study of the association between pupil mobility and attainment in national tests and examinations in an inner London borough. The first article (Strand & Demie, 2006) examined the association of pupil mobility with attainment and progress during primary school. It concluded that pupil mobility had little impact on performance in national tests at age 11, once pupilsâ prior attainment at age 7 and other pupil background factors such as age, sex, special educational needs, stage of fluency in English and socio-economic disadvantage were taken into account. The present article reports the results for secondary schools (age 11-16). The results indicate that pupil mobility continues to have a significant negative association with performance in public examinations at age 16, even after including statistical controls for prior attainment at age 11 and other pupil background factors. Possible reasons for the contrasting results across school phases are explored. The implications for policy and further research are discussed
Educational aspirations in inner city schools
The research aimed to assess the nature and level of pupilsâ educational aspirations and to elucidate the factors that influence these aspirations. A sample of five inner city comprehensive secondary schools were selected by their Local Authority because of poor pupil attendance, below average examination results and low rates of continuing in full-time education after the age of 16. Schools were all ethnically mixed and co-educational. Over 800 pupils aged 12-14 completed a questionnaire assessing pupilsâ experience of home, school and their peers. A sub-sample of 48 pupils selected by teachers to reflect ethnicity and ability levels in individual schools also participated in detailed focus group interviews. There were no significant differences in aspirations by gender or year group, but differences between ethnic groups were marked. Black African, Asian Other and Pakistani groups had significantly higher educational aspirations than the White British group, who had the lowest aspirations. The results suggest the high aspirations of Black African, Asian Other and Pakistani pupils are mediated through strong academic self-concept, positive peer support, a commitment to schooling and high educational aspirations in the home. They also suggest that low educational aspirations may have different mediating influences in different ethnic groups. The low aspirations of White British pupils seem to relate most strongly to poor academic self-concept and low educational aspirations in the home, while for Black Caribbean pupils disaffection, negative peers and low commitment to schooling appear more relevant. Interviews with pupils corroborated the above findings and further illuminated the factors students described as important in their educational aspirations. The results are discussed in relation to theories of aspiration which stress its nature as a cultural capacity
SACMAN automated canal control system
Presented during the Third international conference on irrigation and drainage held March 30 - April 2, 2005 in San Diego, California. The theme of the conference was "Water district management and governance."Includes bibliographical references.Many irrigation districts currently operate their main canals, pumping plants, etc. remotely with Supervisory Control and Data Acquisition (SCADA) software. This is usually manual operation with perhaps a few local automatic control features. SacMan (software for automated canal management) is a software package that adds canal automation logic to commercially-available, windows-based SCADA packages. It allows the user to implement a variety of automatic control features, including complete automatic control, where feasible. It was developed through research at the U.S. Water Conservation Laboratory in Phoenix, AZ. SacMan has several levels of implementation ranging from manual control to full automatic control, including upstream level control, flow rate control, routing of known demand changes, and full (distant) downstream level control. SacMan interfaces with commercial Supervisory Control and Data Acquisition (SCADA) software, currently iFix by GE Fanuc (formerly Intellution, Inc.), but potentially applicable to other SCADA packages. SacMan was field tested on the WM lateral canal at the Maricopa Stanfield Irrigation and Drainage District (MSIDD) in central Arizona. In July/August 2004, SacMan successfully operated the WM canal for a period of 30 days, nearly continuously. This paper describes the features of this canal automation software and some results from this long-term testing.Sponsored by USCID; co-sponsored by Association of California Water Agencies and International Network for Participatory Irrigation Management
Double precision trajectory program /DPTRAJ 2.2C/
Four part program computes trajectory of space probe moving in solar system and subject to variety of forces
The limits of social class in explaining ethnic gaps in educational attainment
This paper reports an analysis of the educational attainment and progress between age 11 and age 14 of over 14,500 students from the nationally representative Longitudinal Study of Young People in England (LSYPE). The mean attainment gap in national tests at age 14 between White British and several ethnic minority groups were large, more than three times the size of the gender gap, but at the same time only about one-third of the size of the social class gap. Socio-economic variables could account for the attainment gaps for Black African, Pakistani and Bangladeshi students, but not for Black Caribbean students. Further controls for parental and student attitudes, expectations and behaviours indicated minority ethnic groups were on average more advantaged on these measures than White British students, but this was not reflected proportionately in their levels of attainment. Black Caribbean students were distinctive as the only group making less progress than White British students between age 11 and 14 and this could not be accounted for by any of the measured contextual variables. Possible explanations for the White British-Black Caribbean gap are considered
Photometric and Spectroscopic Analysis of Cool White Dwarfs with Trigonometric Parallax Measurements
A photometric and spectroscopic analysis of 152 cool white dwarf stars is
presented. The discovery of 7 new DA white dwarfs, 2 new DQ white dwarfs, 1 new
magnetic white dwarf, and 3 weak magnetic white dwarf candidates, is reported,
as well as 19 known or suspected double degenerates. The photometric energy
distributions, the Halpha line profiles, and the trigonometric parallax
measurements are combined and compared to model atmosphere calculations to
determine the effective temperature and the radius of each object, and also to
constrain the atmospheric composition. New evolutionary sequences with C/O
cores with thin and thick hydrogen layers are used to derive masses and ages.
We confirm the existence of a range in Teff between 5000 and 6000K where almost
all white dwarfs have H-rich atmospheres. There is little evidence for mixed
H/He dwarfs, with the exception of 2 He-rich DA stars, and 5 C2H white dwarfs
which possibly have mixed H/He/C atmospheres. The DQ sequence terminates near
6500K, below which they are believed to turn into C2H stars. True DC stars
slightly above this temperature are found to exhibit H-like energy
distributions despite the lack of Halpha absorption. Attempts to interpret the
chemical evolution show the problem to be complex. Convective mixing is
necessary to account for the non-DA to DA ratio as a function of temperature.
The presence of helium in cool DA stars, the existence of the non-DA gap, and
the peculiar DC stars are also explained in terms of convective mixing,
although our understanding of how this mechanism works needs to be revised. The
oldest object in our sample is about 7.9 Gyr or 9.7 Gyr old depending on
whether thin or thick hydrogen layer models are used. The mean mass of our
sample is 0.65 +/- 0.20 Msun.Comment: Accepted by ApJ Suppl (~April 2001); 79 pages incl. 25 figure
Distributional exact diagonalization formalism for quantum impurity models
We develop a method for calculating the self-energy of a quantum impurity
coupled to a continuous bath by stochastically generating a distribution of
finite Anderson models that are solved by exact diagonalization, using the
noninteracting local spectral function as a probability distribution for the
sampling. The method enables calculation of the full analytic self-energy and
single-particle Green's function in the complex frequency plane, without
analytic continuation, and can be used for both finite and zero temperature at
arbitrary fillings. Results are in good agreement with imaginary frequency data
from continuous-time quantum Monte Carlo calculations for the single impurity
Anderson model and the two-orbital Hubbard model within dynamical mean field
theory (DMFT) as well as real frequency data for self energy of the single band
Hubbard model within DMFT using numerical renormalization group. The method
should be applicable to a wide range of quantum impurity models and
particularly useful when high-precision real frequency results are sought.Comment: Two band calculation updated, 4 pages, 4 figure
AGN Environments in the Sloan Digital Sky Survey I: Dependence on Type, Redshift, and Luminosity
We explore how the local environment is related to the redshift, type, and
luminosity of active galactic nuclei (AGN). Recent simulations and observations
are converging on the view that the extreme luminosity of quasars is fueled in
major mergers of gas-rich galaxies. In such a picture, quasars are expected to
be located in regions with a higher density of galaxies on small scales where
mergers are more likely to take place. However, in this picture, the activity
observed in low-luminosity AGN is due to secular processes that are less
dependent on the local galaxy density. To test this hypothesis, we compare the
local photometric galaxy density on kiloparsec scales around spectroscopic Type
I and Type II quasars to the local density around lower luminosity
spectroscopic Type I and Type II AGN. To minimize projection effects and
evolution in the photometric galaxy sample we use to characterize AGN
environments, we place our random control sample at the same redshift as our
AGN and impose a narrow redshift window around both the AGN and control
targets. We find that higher luminosity AGN have more overdense environments
compared to lower luminosity AGN on all scales out to our 2\Mpchseventy
limit. Additionally, in the range , Type II
quasars have similarly overdense environments to those of bright Type I quasars
on all scales out to our 2\Mpchseventy limit, while the environment of dimmer
Type I quasars appears to be less overdense than the environment of Type II
quasars. We see increased overdensity for Type II AGN compared to Type I AGN on
scales out to our limit of 2\Mpchseventy in overlapping redshift ranges. We
also detect marginal evidence for evolution in the number of galaxies within
2\Mpchseventy of a quasar with redshift.Comment: 30 pages, 9 figures. Major revisions made for current version. Some
content in previous version has been removed to refocus content on redshift
and type effects. This content will be deferred to later work
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