12,682 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 government’s ‘standards agenda’. However, the emerging discourse of ‘new professionalism’ has raised the profile of professional development in schools, and together with union learning representatives, there are opportunities to secure real improvements in teachers’ 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 Gramsci’s notion of the ‘organic intellectual’, the paper argues that union learning representatives have a key role as organisers of ideas – creating spaces in which the ideological dominance of current policy orthodoxy might be challenged
Chemical chronology of the Southern Coalsack
We demonstrate how the observed H2O ice column densities toward three dense
globules in the Southern Coalsack could be used to constrain the ages of these
sources. We derive ages of ~10^5 yr, in agreement with dynamical studies of
these objects. We have modelled the chemical evolution of the globules, and
show how the molecular abundances are controlled by both the gas density and
the initial chemical conditions as the globules formed. Based on our derived
ages, we predict the column densities of several species of interest. These
predictions should be straightforward to test by performing molecular line
observationsComment: 10 pages, 4 figures, in press at MNRA
A Variational Approach to Bound States in Quantum Field Theory
We consider here in a toy model an approach to bound state problem in a
nonperturbative manner using equal time algebra for the interacting field
operators. Potential is replaced by offshell bosonic quanta inside the bound
state of nonrelativistic particles. The bosonic dressing is determined through
energy minimisation, and mass renormalisation is carried out in a
nonperturbative manner. Since the interaction is through a scalar field, it
does not include spin effects. The model however nicely incorporates an
intuitive picture of hadronic bound states in which the gluon fields dress the
quarks providing the binding between them and also simulate the gluonic content
of hadrons in deep inelastic collisions.Comment: latex, revtex, 22 page
The unrestricted Skyrme-tensor time-dependent Hartree-Fock and its application to the nuclear response from spherical to triaxial nuclei
The nuclear time-dependent Hartree-Fock model formulated in the
three-dimensional space,based on the full Skyrme energy density functional and
complemented with the tensor force,is presented for the first time. Full
self-consistency is achieved by the model. The application to the isovector
giant dipole resonance is discussed in the linear limit, ranging from spherical
nuclei (16O, 120Sn) to systems displaying axial or triaxial deformation (24Mg,
28Si, 178Os, 190W, 238U).
Particular attention is paid to the spin-dependent terms from the central
sector of the functional, recently included together with the tensor. They turn
out to be capable of producing a qualitative change on the strength
distribution in this channel. The effect on the deformation properties is also
discussed. The quantitative effects on the linear response are small and,
overall, the giant dipole energy remains unaffected.
Calculations are compared to predictions from the (quasi)-particle random
phase approximation and experimental data where available, finding good
agreement
Molecular orientational dynamics of the endohedral fullerene ScN@C as probed by C and Sc NMR
We measure 13C and 45Sc NMR lineshapes and spin-lattice relaxation times (T1)
to probe the orientational dynamics of the endohedral metallofullerene
Sc3N@C80. The measurements show an activated behavior for molecular
reorientations over the full temperature range with a similar behavior for the
temperature dependence of the 13C and 45Sc data. Combined with spectral data
from Magic Angle Spinning (MAS) NMR, the measurements can be interpreted to
mean the motion of the encapsulated Sc3N molecule is independent of that of the
C80 cage, although this requires the similar temperature dependence of the 13C
and 45Sc spin-lattice relaxation times to be coincidental. For the Sc3N to be
fixed to the C80 cage, one must overcome the symmetry breaking effect this has
on the Sc3N@C80 system since this would result in more than the observed two
13C lines.Comment: 6 pages, 5 figure
l/f Noise in the Superconducting Transition of a MgB2 Thin Film
The noise voltage spectral density in the superconducting transition of a MgB2 thin film on a SiN-coated Si thick substrate was measured over the frequency range 1 Hz-to-1 KHz. Using established bolometer noise theory the theoretical noise components due to Johnson, 1/f(excess) and phonon noise are modeled to the measured data. It is shown that for the case of a MgB2 thin film in the vicinity of the mid-point of transition, coupled to a heat sink via a fairly high thermal conductance (approximately equal to 10(sup -1) W/K)) that the measured noise voltage spectrum is 1/f limited and exhibits lit dependence with a varying between 0.3 and 0.5 in the measured frequency range. At a video frame rate frequency of 30 Hz the measured noise voltage density in the film is approximately equal to 61 nV /the square root of HZ, using this value an upper limit of electrical NEP approximately equal to 0.67pW / the square root of Hz is implied for a practical MgB2 bolometer operating at 36.1 K
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