1,164 research outputs found
A Spider, an Octopus, or an Animal Just Coming into Existence? Designing a Curriculum for Librarians to Support Research Data Management
The paper explains the approach taken in the UK JISC funded RDMRose project to developing a study module / Open Educational Resource about Research Data Management (RDM) for librarians. The resource was developed collaboratively between the University of Sheffield Information School and the libraries at the Universities of Leeds, Sheffield and York. Curriculum design principles such as an emphasis on exploring the nature of research and on other professional services supporting RDM were based on requirements gathering from focus groups and the literature. The content of the eight half-day sessions is briefly outlined. The paper goes on to explore how the learning materials were evaluated by this first cohort of learners and readjusted to respond to feedback. Future plans for co-producing an RDM related learning resource through a student-centred process and to create a sustainable learning network are discussed
Development of deep Vs profiles and site periods for the Canterbury region
Recent field investigations were carried out to define the shear wave
velocity (VS) profile and site periods across the Canterbury region, supplementing earlier
efforts in urban Christchurch. Active source surface wave testing, ambient wave field
(passive) and H/V spectral ratio methods were used to characterise the soil profile in the
region. H/V spectral ratio peaks indicate site periods in the range of 5-7 seconds across
much of the Canterbury Plains, broadly consistent with those based on a 1D velocity
model for the region. Site periods decrease rapidly in the vicinity of the Canterbury
foothills and the Banks Peninsula outcrops. In Christchurch, the Riccarton Gravels result
in a significant mode of vibration that has a much shorter period than the site period of
the entire soil column down to basement rock
New perturbative solutions of the Kerr-Newman dilatonic black hole field equations
This work describes new perturbative solutions to the classical,
four-dimensional Kerr--Newman dilaton black hole field equations. Our solutions
do not require the black hole to be slowly rotating. The unperturbed solution
is taken to be the ordinary Kerr solution, and the perturbation parameter is
effectively the square of the charge-to-mass ratio of the
Kerr--Newman black hole. We have uncovered a new, exact conjugation (mirror)
symmetry for the theory, which maps the small coupling sector to the strong
coupling sector (). We also calculate the gyromagnetic ratio of
the black hole.Comment: Revtex, 27 page
A new non-Fermi liquid fixed point
We study a new exchange interaction in which the conduction electrons with
pseudo spin interact with the impurity spin . Due to the
overscreening of the impurity spin by higher conduction electron spin, a new
non-trivial intermediate coupling strength fixed point is realized. Using the
numerical renormalization group (NRG), we show that the low-energy spectra are
described by a non-Fermi liquid excitation spectrum. A conformal field theory
analysis is compared with NRG results and excellent agreement is obtained.
Using the double fusion rule to generate the operator spectrum with the
conformal theory, we find that the specific heat coefficient and magnetic
susceptibility will diverge as , that the scaling dimension of an
applied magnetic field is , and that exchange anisotropy is always
relevant. We discuss the possible relevance of our work to two-level system
Kondo materials and dilute cerium alloys, and we point out a paradox in
understanding the Bethe-Ansatz solutions to the multichannel Kondo model.Comment: Revised. 20 page
What are communities of practice? A comparative review of four seminal works
This paper is a comparative review of four seminal works on communities of practice. It is argued that the ambiguities of the terms community and practice are a source of the concept's reusability allowing it to be reappropriated for different purposes, academic and practical. However, it is potentially confusing that the works differ so markedly in their conceptualizations of community, learning, power and change, diversity and informality. The three earlier works are underpinned by a common epistemological view, but Lave and Wenger's 1991 short monograph is often read as primarily about the socialization of newcomers into knowledge by a form of apprenticeship, while the focus in Brown and Duguid's article of the same year is, in contrast, on improvising new knowledge in an interstitial group that forms in resistance to management. Wenger's 1998 book treats communities of practice as the informal relations and understandings that develop in mutual engagement on an appropriated joint enterprise, but his focus is the impact on individual identity. The applicability of the concept to the heavily individualized and tightly managed work of the twenty-first century is questionable. The most recent work by Wenger â this time with McDermott and Snyder as coauthors â marks a distinct shift towards a managerialist stance. The proposition that managers should foster informal horizontal groups across organizational boundaries is in fact a fundamental redefinition of the concept. However it does identify a plausible, if limited, knowledge management (KM) tool. This paper discusses different interpretations of the idea of 'co-ordinating' communities of practice as a management ideology of empowerment
Enhancement of the Two-channel Kondo Effect in Single-Electron boxes
The charging of a quantum box, coupled to a lead by tunneling through a
single resonant level, is studied near the degeneracy points of the Coulomb
blockade. Combining Wilson's numerical renormalization-group method with
perturbative scaling approaches, the corresponding low-energy Hamiltonian is
solved for arbitrary temperatures, gate voltages, tunneling rates, and energies
of the impurity level. Similar to the case of a weak tunnel barrier, the shape
of the charge step is governed at low temperatures by the non-Fermi-liquid
fixed point of the two-channel Kondo effect. However, the associated Kondo
temperature TK is strongly modified. Most notably, TK is proportional to the
width of the level if the transmission through the impurity is close to unity
at the Fermi energy, and is no longer exponentially small in one over the
tunneling matrix element. Focusing on a particle-hole symmetric level, the
two-channel Kondo effect is found to be robust against the inclusion of an
on-site repulsion on the level. For a large on-site repulsion and a large
asymmetry in the tunneling rates to box and to the lead, there is a sequence of
Kondo effects: first the local magnetic moment that forms on the level
undergoes single-channel screening, followed by two-channel overscreening of
the charge fluctuations inside the box.Comment: 21 pages, 19 figure
Equidistribution of Heegner Points and Ternary Quadratic Forms
We prove new equidistribution results for Galois orbits of Heegner points
with respect to reduction maps at inert primes. The arguments are based on two
different techniques: primitive representations of integers by quadratic forms
and distribution relations for Heegner points. Our results generalize one of
the equidistribution theorems established by Cornut and Vatsal in the sense
that we allow both the fundamental discriminant and the conductor to grow.
Moreover, for fixed fundamental discriminant and variable conductor, we deduce
an effective surjectivity theorem for the reduction map from Heegner points to
supersingular points at a fixed inert prime. Our results are applicable to the
setting considered by Kolyvagin in the construction of the Heegner points Euler
system
A Fermi Surface study of BaKBiO
We present all electron computations of the 3D Fermi surfaces (FS's) in
BaKBiO for a number of different compositions based on the
selfconsistent Korringa-Kohn-Rostoker coherent-potential-approximation
(KKR-CPA) approach for incorporating the effects of Ba/K substitution. By
assuming a simple cubic structure throughout the composition range, the
evolution of the nesting and other features of the FS of the underlying
pristine phase is correlated with the onset of various structural transitions
with K doping. A parameterized scheme for obtaining an accurate 3D map of the
FS in BaKBiO for an arbitrary doping level is developed. We
remark on the puzzling differences between the phase diagrams of
BaKBiO and BaPbBiO by comparing aspects
of their electronic structures and those of the end compounds BaBiO,
KBiO and BaPbO. Our theoretically predicted FS's in the cubic phase are
relevant for analyzing high-resolution Compton scattering and
positron-annihilation experiments sensitive to the electron momentum density,
and are thus amenable to substantial experimental verification.Comment: 12 pages, 7 figures, to appear in Phys. Rev.
Supersymmetric Branes on AdS_5 x Y^{p,q} and their Field Theory Duals
We systematically study supersymmetric embeddings of D-brane probes of
different dimensionality in the AdS_5xY^{p,q} background of type IIB string
theory. The main technique employed is the kappa symmetry of the probe's
worldvolume theory. In the case of D3-branes, we recover the known three-cycles
dual to the dibaryonic operators of the gauge theory and we also find a new
family of supersymmetric embeddings. The BPS fluctuations of dibaryons are
analyzed and shown to match the gauge theory results. Supersymmetric
configurations of D5-branes, representing domain walls, and of spacetime
filling D7-branes (which can be used to add flavor) are also found. We also
study the baryon vertex and some other embeddings which break supersymmetry but
are nevertheless stable.Comment: LaTeX, 2 figures, 54 pages; v2: discussions sharpened at several
points, new subsection and references adde
- âŠ