199 research outputs found
Challenging the orthodoxy: union learning representatives as organic intellectuals
Teacher education and continuing professional development have become a key areas of controversy in England since the period of school sector restructuring following the 1988 Education Reform Act. More recently teacher training and professional development have often been used to promote and reinforce a narrow focus on the governmentâs âstandards agendaâ. However, the emerging discourse of ânew professionalismâ has raised the profile of professional development in schools, and together with union learning representatives, there are opportunities to secure real improvements in teachersâ access to continuing professional development. This paper argues however that union learning representatives must go beyond advocating for better access to professional development and should raise more fundamental questions about the nature of professional development and the education system it serves. Drawing on Gramsciâs notion of the âorganic intellectualâ, the paper argues that union learning representatives have a key role as organisers of ideas â creating spaces in which the ideological dominance of current policy orthodoxy might be challenged
Vertebral Artery Injury: Case Report and Review of Operative Approaches
Traumatic injury to the upper third of the neck, cephalad to the angle of the mandible, distorts the complexity of normal anatomy and underscores the importance of preoperative arteriography when possible. This report describes the case of a young man who was brought to the Emergency Room of our hospital suffering from a severe gunshot wound to the cervical spine, vertebral artery, and maxillofacial skeleton. His injury was successfully managed by combining a standard arterolateral incision with a procedure that has been described for exposing retro maxillary tumors. This operative technique provided the surgeon with direct access to the injury, controlled the loss of blood, and permitted repair of accompanying pharyngeal and facial injuries. Our report also reviews the technical considerations and pertinent surgical anatomy of this rare combination of Injuries
Teacher unionism in changing times: is this the real ânew unionismâ?
This article provides a case study of union change in an environment in which radical school restructuring is taking place, and active strategies to weaken and marginalize organized teachers are being pursued by the state. The case study union is the National Union of Teachers in England. The article explores a number of different strategies open to teacher unions, utilizing a framework provided by Turner (2004). Drawing on data collected at a national level, and in three local authority areas, I argue that the National Union of Teachersâ response to the erosion of collective bargaining is best presented as an amalgam of strategies focused on workplace organizing, political campaigning, and coalition building. The data demonstrate considerable congruence between national and local strategies, although local data reveal considerable challenges in implementation and consequently considerable unevenness in local experiences
Resistive state of superconducting structures with fractal clusters of a normal phase
The effect of morphologic factors on magnetic flux dynamics and critical
currents in percolative superconducting structures is considered. The
superconductor contains the fractal clusters of a normal phase, which act as
pinning centers. The properties of these clusters are analyzed in the general
case of gamma-distribution of their areas. The statistical characteristics of
the normal phase clusters are studied, the critical current distribution is
derived, and the dependencies of the main statistical parameters on the fractal
dimension are found. The effect of fractal clusters of a normal phase on the
electric field induced by the motion of the magnetic flux after the vortices
have been broken away from pinning centers is considered. The voltage-current
characteristics of fractal superconducting structures in a resistive state for
an arbitrary fractal dimension are obtained. It is found that the fractality of
the boundaries of normal phase clusters intensifies magnetic flux trapping and
thereby increases the current-carrying capability of the superconductor.Comment: 15 pages with 8 figures, revtex3, alternative e-mail of author is
[email protected]
Triple sign reversal of Hall effect in HgBa_{2}CaCu_{2}O_{6} thin films after heavy-ion irradiations
Triple sign reversal in the mixed-state Hall effect has been observed for the
first time in ion-irradiated HgBa_{2}CaCu_{2}O_{6} thin films. The negative dip
at the third sign reversal is more pronounced for higher fields, which is
opposite to the case of the first sign reversal near T_c in most high-T_c
superconductors. These observations can be explained by a recent prediction in
which the third sign reversal is attributed to the energy derivative of the
density of states and to a temperature-dependent function related to the
superconducting energy gap. These contributions prominently appear in cases
where the mean free path is significantly decreased, such as our case of
ion-irradiated thin films.Comment: 4 pages, 3 eps figures, submitted Phys. Rev. Let
Recommended from our members
Flux-line pinning by the grain boundary in niobium bicrystals
Flux-line pinning by the grain boundary in niobium bicrystals was investigated by making four-terminal measurements of the critical current and neutron diffraction measurements of the flux-line bending. The elementary pinning interaction is estimated from the critical current data by using an approximate theory of the current distribution on the grain boundary. The data reported here are mainly for a sample in which the applied magnetic field is parallel to the (111) and the (001) crystal directions in the two grains when it is in the plane of the boundary and perpendicular to the current direction. Evidence is seen of grain boundary faceting and of a flux-flow rectification effect that peaks as a function of temperature below 3/sup 0/K. The scale of the grain-boundary pinning is consistent with the quasiparticle-scattering theory
Dynamics of the magnetic flux trapped in fractal clusters of normal phase in a superconductor
The influence of geometry and morphology of superconducting structure on
critical currents and magnetic flux trapping in percolative type-II
superconductor is considered. The superconductor contains the clusters of a
normal phase, which act as pinning centers. It is found that such clusters have
significant fractal properties. The main features of these clusters are studied
in detail: the cluster statistics is analyzed; the fractal dimension of their
boundary is estimated; the distribution of critical currents is obtained, and
its peculiarities are explored. It is examined thoroughly how the finite
resolution capacity of the cluster geometrical size measurement affects the
estimated value of fractal dimension. The effect of fractal properties of the
normal phase clusters on the electric field arising from magnetic flux motion
is investigated in the case of an exponential distribution of cluster areas.
The voltage-current characteristics of superconductors in the resistive state
for an arbitrary fractal dimension are obtained. It is revealed that the
fractality of the boundaries of the normal phase clusters intensifies the
magnetic flux trapping and thereby raises the critical current of a
superconductor.Comment: revtex, 16 pages with 1 table and 5 figures; text and figures are
improved; more detailed version with geometric probability analisys of the
distribution of entry points into weak links over the perimeter of a normal
phase clusters and one additional figure is published in Phys.Rev.B;
alternative e-mail of author is [email protected]
A Happy Abundance : Tales, Memoirs and More Past and Present in Wayne, Maine
https://digitalmaine.com/wayne_books/1002/thumbnail.jp
AMPA Receptor Activation Causes Silencing of AMPA Receptor-Mediated Synaptic Transmission in the Developing Hippocampus
Agonist-induced internalization of transmembrane receptors is a widespread biological phenomenon that also may serve as a mechanism for synaptic plasticity. Here we show that the agonist AMPA causes a depression of AMPA receptor (AMPAR) signaling at glutamate synapses in the CA1 region of the hippocampus in slices from developing, but not from mature, rats. This developmentally restricted agonist-induced synaptic depression is expressed as a total loss of AMPAR signaling, without affecting NMDA receptor (NMDAR) signaling, in a large proportion of the developing synapses, thus creating AMPAR silent synapses. The AMPA-induced AMPAR silencing is induced independently of activation of mGluRs and NMDARs, and it mimics and occludes stimulus-induced depression, suggesting that this latter form of synaptic plasticity is expressed as agonist-induced removal of AMPARs. Induction of long-term potentiation (LTP) rendered the developing synapses resistant to the AMPA-induced depression, indicating that LTP contributes to the maturation-related increased stability of these synapses. Our study shows that agonist binding to AMPARs is a sufficient triggering stimulus for the creation of AMPAR silent synapses at developing glutamate synapses
A meta-analysis of genome-wide association studies identifies 17 new Parkinson's disease risk loci
Common variant genome-wide association studies (GWASs) have, to date, identified >24 risk loci for Parkinson's disease (PD). To discover additional loci, we carried out a GWAS comparing 6,476 PD cases with 302,042 controls, followed by a meta-analysis with a recent study of over 13,000 PD cases and 95,000 controls at 9,830 overlapping variants. We then tested 35 loci (P < 1 Ă 10â6) in a replication cohort of 5,851 cases and 5,866 controls. We identified 17 novel risk loci (P < 5 Ă 10â8) in a joint analysis of 26,035 cases and 403,190 controls. We used a neurocentric strategy to assign candidate risk genes to the loci. We identified protein-altering or cisâexpression quantitative trait locus (cis-eQTL) variants in linkage disequilibrium with the index variant in 29 of the 41 PD loci. These results indicate a key role for autophagy and lysosomal biology in PD risk, and suggest potential new drug targets for PD
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