4,717 research outputs found
The impact of broadband in schools
The report reviews evidence for the impact of broadband in English schools, exploring; Variations in provision in level of broadband connectivity; Links between the level of broadband activity and nationally accessible performance data; Aspects of broadband connectivity and the school environment that contribute to better outcomes for pupils and teachers; Academic and motivational benefits associated with educational uses of this technology
Patterns of gene expression in schistosomes: localization by whole mount in situ hybridization
rom the identification of genes to the characterization of their functions and interactions. Developmental biologists have long used whole mount in situ hybridization (WISH) to determine gene expression patterns, as a vital tool for formulating and testing hypotheses about function. This paper describes the application of WISH to the study of gene expression in larval and adult schistosomes. Fixed worms were permeablized by proteinase K treatment for hybridization with digoxygenin-labelled RNA probes, with binding being detected by alkaline phosphatase-coupled anti-digoxygenin antibodies, and BM Purple substrate. Discrete staining patterns for the transcripts of the molecules Sm29, cathepsin L, antigen 10.3 and chorion were observed in the tegument cell bodies, gut epithelium, oesophageal gland and vitelline lobules, respectively, of adult worms. Transcripts of the molecules SGTP4, GP18-22 and cathepsin L were localized to tegument cell bodies and embryonic gut, respectively, of lung schistosomula. We also showed that Fast Red TR fluorescent substrate can refine the pattern of localization permitting use of confocal microscopy. We believe that method of WISH will find broad application, in synergy with other emerging post-genomic techniques, such as RNA interference, to studies focused at increasing our molecular understanding of schistosomes
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Tablet PCs in schools: Case study report: A report for Becta by the Open University
The publication provides an analysis of twelve case studies involving schools in England that were using Tablet PCs. The analysis is complemented by brief individual reports describing aspects of how each of these schools was using Tablet PCs
Domain-wall profile in the presence of anisotropic exchange interactions: Effective on-site anisotropy
Starting from a D-dimensional XXZ ferromagnetic Heisenberg model in an
hypercubic lattice, it is demonstrated that the anisotropy in the exchange
coupling constant leads to a D-dependent effective on-site anisotropy
interaction often ignored for D>1. As a result the effective width of the wall
depends on the dimensionality of the system. It is shown that the effective
one-dimensional Hamiltonian is not the one-dimensional XXZ version as assumed
in previous theoretical work. We derive a new expression for the wall profile
that generalizes the standard Landau-Lifshitz form. Our results are found to be
in very good agreement with earlier numerical work using the Monte Carlo
method. Preceding theories concerning the domain wall contribution to
magnetoresistance have considered the role of D only through the modification
of the density of states in the electronic band structure. This Brief Report
reveals that the wall profile itself contains an additional D dependence for
the case of anisotropic exchange interactions.Comment: 4 pages; new title and abstract; 1 figure comparing our results with
earlier numerical work; a more general model containing the usual on-site
anisotropy; new remarks and references on the following two topics: (a)
experimental evidence for the existence of spin exchange anisotropy, and (b)
preceding theories concerning the domain wall contribution to
magnetoresistance; to appear in Phys. Rev.
A ZZ Ceti white dwarf in SDSS J133941.11+484727.5
We present time-resolved spectroscopy and photometry of the cataclysmic
variable (CV) SDSSJ133941.11+484727.5 (SDSS1339) which has been discovered in
the Sloan Digital Sky Survey Data Release 4. The orbital period determined from
radial velocity studies is 82.524(24)min, close to the observed period minimum.
The optical spectrum of SDSS1339 is dominated to 90% by emission from the white
dwarf. The spectrum can be successfully reproduced by a three-component model
(white dwarf, disc, secondary) with Twd=12500K for a fixed log g=8.0, d=170pc,
and a spectral type of the secondary later than M8. The mass transfer rate
corresponding to the optical luminosity of the accretion disc is very
low,~1.7x10^-13Msun/yr. Optical photometry reveals a coherent variability at
641s with an amplitude of 0.025mag, which we interpret as non-radial pulsations
of the white dwarf. In addition, a long-period photometric variation with a
period of either 320min or 344min and an amplitude of 0.025mag is detected,
which bears no apparent relation with the orbital period of the system. Similar
long-period photometric signals have been found in the CVs
SDSSJ123813.73-033933.0, SDSSJ204817.85-061044.8, GW Lib and FS Aur, but so far
no working model for this behaviour is available.Comment: MNRAS, in press, 8 pages, 10 figures, some figures downgraded to meet
the file size constraint of arxiv.or
Intrinsic quadrupole moment of the nucleon
We address the question of the intrinsic quadrupole moment Q_0 of the nucleon
in various models. All models give a positive intrinsic quadrupole moment for
the proton. This corresponds to a prolate deformation. We also calculate the
intrinsic quadrupole moment of the Delta(1232). All our models lead to a
negative intrinsic quadrupole moment of the Delta corresponding to an oblate
deformation.Comment: 17 pages, 5 figure
Thermally assisted domain walls quantum tunneling at the high temperature range
A theoretical and numerical investigations of the quantum tunneling of the
domain walls in ferromagnets and weak ferromagnets was performed taking into
account the interaction between walls and thermal excitations of a crystal. The
numerical method for calculations of the probability of a thermally stimulated
quantum depinning as the function of temperature at the wide temperature range
has been evolved.Comment: 5 pages, 3 figure
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