119,241 research outputs found
A climate for change
This paper reports on the findings of a research project investigating the nature of participation of secondary school students in a collaborative research programme. Four groups of students, aged 14 to 15 years old, from a secondary school in the United Kingdom (UK) participated in the study. The students involved in the programme took the role of researchers investigating their peers’ perceptions of climate change using video to visually record their findings. University researchers worked collaboratively with the school students and a teacher from the school through an approach that empowered the students within the research process. Drawing from the ideas and issues raised from an initial briefing session, each group of students developed a short interview schedule to be used whilst investigating the views of their peers. Although the project was on a small scale, the data gathered from the brainstorming activity, video reports and reflective discussions provided a useful snap shot of how the participating students perceived their experience and the nature of their involvement in the research process. The research approach enabled students to take on the role of investigator when interviewing their peers and to offer a voice for both themselves and their peers. Introduction</p
Quark Condensates: Flavour Dependence
We determine the q-bar q condensate for quark masses from zero up to that of
the strange quark within a phenomenologically successful modelling of continuum
QCD by solving the quark Schwinger-Dyson equation. The existence of multiple
solutions to this equation is the key to an accurate and reliable extraction of
this condensate using the operator product expansion. We explain why
alternative definitions fail to give the physical condensate.Comment: 9 pages, 7 figures, uses appolb.cls, LaTeX. Talk presented by R.
Williams at the EURIDICE Final Meeting, August 24-27th, 2006, Kazimierz,
Polan
Direct observation of voids in the vacancy excess region of ion bombarded silicon
The results reported in this letter indicate that the spatial separation of the vacancy and interstitial excesses which result from ion bombardment gives rise to stable voids upon annealing at 850 °C even for implants where the projected ion range is only of the order of a few thousand Ångstrom. Such voids have been observed directly by transmission electron microscopy. Furthermore, in cases where both voids and interstitial-based defects are present at different depths, it is found that Au has a strong preference for decorating void surfaces and hence Au can, indeed, be used as a selective detector of open volume defects in Si.One of the authors ~J.W.-L.!
acknowledges the Australian Research Council for financial
support
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Petrology and geochemistry of nakhlite MIL 03346: A new Martian meteorite from Antarctica
MIL 03346 is the first nakhlite in the US Antarctic collection. We have performed detailed mineralogical and bulk-geochemical investigations to compare petrogenesis of this Martian meteorite with other nakhlites
Degree of Cajal-Retzius cell mislocalisation correlates with the severity of structural brain defects in mouse models of dystroglycanopathy
The secondary dystroglycanopathies are characterized by the hypoglycosylation of alpha dystroglycan, and are associated with mutations in at least 18 genes that act on the glycosylation of this cell surface receptor rather than the Dag1 gene itself. At the severe end of the disease spectrum, there are substantial structural brain defects, the most striking of which is often cobblestone lissencephaly. The aim of this study was to determine the gene‐specific aspects of the dystroglycanopathy brain phenotype through a detailed investigation of the structural brain defects present at birth in three mouse models of dystroglycanopathy—the FKRPKD, which has an 80% reduction in Fkrp transcript levels; the Pomgnt1null, which carries a deletion of exons 7–16 of the Pomgnt1 gene; and the Largemyd mouse, which carries a deletion of exons 5–7 of the Large gene. We show a rostrocaudal and mediolateral gradient in the severity of brain lesions in FKRPKD, and to a lesser extent Pomgnt1null mice. Furthermore, the mislocalization of Cajal–Retzius cells is correlated with the gradient of these lesions and the severity of the brain phenotype in these models. Overall these observations implicate gene‐specific differences in the pathogenesis of brain lesions in this group of disorders
Macrocyclic dizinc(II) alkyl and alkoxide complexes: Reversible CO2 uptake and polymerization catalysis testing
The Multigap RPC: The Time-of-Flight Detector for the ALICE experiment
The selected device for the ALICE Time-of-Flight is the Multigap Resistive Plate Chamber. This detector, consisting of a stack of glass plates, has a time resolution between 60 and 80 ps. We discuss the principle of operation of this detector and present the latest results from the ongoing R&D program
Loading Bose condensed atoms into the ground state of an optical lattice
We optimize the turning on of a one-dimensional optical potential, V_L(x,t) =
S(t) V_0 cos^2(kx) to obtain the optimal turn-on function S(t) so as to load a
Bose-Einstein condensate into the ground state of the optical lattice of depth
V_0. Specifically, we minimize interband excitations at the end of the turn-on
of the optical potential at the final ramp time t_r, where S(t_r) = 1, given
that S(0) = 0. Detailed numerical calculations confirm that a simple unit cell
model is an excellent approximation when the turn-on time t_r is long compared
with the inverse of the band excitation frequency and short in comparison with
nonlinear time \hbar/\mu where \mu is the chemical potential of the condensate.
We demonstrate using the Gross-Pitaevskii equation with an optimal turn-on
function S(t) that the ground state of the optical lattice can be loaded with
very little excitation even for times t_r on the order of the inverse band
excitation frequency
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