417 research outputs found
A Cosmological No-Hair Theorem
A generalisation of Price's theorem is given for application to Inflationary
Cosmologies. Namely, we show that on a Schwarzschild--de Sitter background
there are no static solutions to the wave or gravitational perturbation
equations for modes with angular momentum greater than their intrinsic spin.Comment: 9 pages, NCL94 -TP4, (Revtex
Logarithmic deformations of the rational superpotential/Landau-Ginzburg construction of solutions of the WDVV equations
The superpotential in the Landau-Ginzburg construction of solutions to the Witten-Dijkgraaf-Verlinde-Verlinde (or WDVV) equations is modified to include logarithmic terms. This results in deformations - quadratic in the deformation parameters- of the normal prepotential solutions of the WDVV equations. Such solutions satisfy various pseudo-quasi-homogeneity conditions, on assigning a notional weight to the deformation parameters. These solutions originate in the so-called `water-bag' reductions of the dispersionless KP hierarchy. This construction includes, as a special case, deformations which are polynomial in the flat coordinates, resulting in a new class of polynomial solutions of the WDVV equations
Gravitational quasinormal modes for Kerr Anti-de Sitter black holes
We investigate the quasinormal modes for gravitational perturbations of
rotating black holes in four dimensional Anti-de Sitter (AdS) spacetime. The
study of the quasinormal frequencies related to these modes is relevant to the
AdS/CFT correspondence. Although results have been obtained for Schwarzschild
and Reissner-Nordstrom AdS black holes, quasinormal frequencies of Kerr-AdS
black holes are computed for the first time. We solve the Teukolsky equations
in AdS spacetime, providing a second order and a Pade approximation for the
angular eigenvalues associated to the Teukolsky angular equation. The
transformation theory and the Regge-Wheeler-Zerilli equations for Kerr-AdS are
obtained.Comment: 20 pages, 13 figures, ReVTe
Cytoplasmic dynein nomenclature
A variety of names has been used in the literature for the subunits of cytoplasmic dynein complexes. Thus, there is a strong need for a more definitive consensus statement on nomenclature. This is especially important for mammalian cytoplasmic dyneins, many subunits of which are encoded by multiple genes. We propose names for the mammalian cytoplasmic dynein subunit genes and proteins that reflect the phylogenetic relationships of the genes and the published studies clarifying the functions of the polypeptides. This nomenclature recognizes the two distinct cytoplasmic dynein complexes and has the flexibility to accommodate the discovery of new subunits and isoforms
H-Branes and Chiral Strings
We add a simple boundary term to the Polyakov action and construct a new
class of D-branes with a single null direction. On the string world-sheet the
system is described by a single quantized left-mode sector of a conformal field
theory. By a Wick rotation of spacetime, we map open strings attached to these
branes into chiral closed strings. We suggest that these so-called H-branes
describe quantum horizons - black hole, cosmological (de-Sitter), etc. We show
how one can get a space/phase space transmutation near the horizon and discuss
the new features of boundary states which become squeezed states.Comment: 27 pages, 5 eps figures, LaTe
Quantized bulk fermions in the Randall-Sundrum brane model
The lowest order quantum corrections to the effective action arising from
quantized massive fermion fields in the Randall-Sundrum background spacetime
are computed. The boundary conditions and their relation with gauge invariance
are examined in detail. The possibility of Wilson loop symmetry breaking in
brane models is also analysed. The self-consistency requirements, previously
considered in the case of a quantized bulk scalar field, are extended to
include the contribution from massive fermions. It is shown that in this case
it is possible to stabilize the radius of the extra dimensions but it is not
possible to simultaneously solve the hierarchy problem, unless the brane
tensions are dramatically fine tuned, supporting previous claims.Comment: 25 pages, 1 figure, RevTe
Implementing health research through academic and clinical partnerships : a realistic evaluation of the Collaborations for Leadership in Applied Health Research and Care (CLAHRC)
Background: The English National Health Service has made a major investment in nine partnerships between
higher education institutions and local health services called Collaborations for Leadership in Applied Health
Research and Care (CLAHRC). They have been funded to increase capacity and capability to produce and
implement research through sustained interactions between academics and health services. CLAHRCs provide a
natural ‘test bed’ for exploring questions about research implementation within a partnership model of delivery.
This protocol describes an externally funded evaluation that focuses on implementation mechanisms and
processes within three CLAHRCs. It seeks to uncover what works, for whom, how, and in what circumstances.
Design and methods: This study is a longitudinal three-phase, multi-method realistic evaluation, which
deliberately aims to explore the boundaries around knowledge use in context. The evaluation funder wishes to see
it conducted for the process of learning, not for judging performance. The study is underpinned by a conceptual
framework that combines the Promoting Action on Research Implementation in Health Services and Knowledge to
Action frameworks to reflect the complexities of implementation. Three participating CLARHCS will provide indepth
comparative case studies of research implementation using multiple data collection methods including
interviews, observation, documents, and publicly available data to test and refine hypotheses over four rounds of
data collection. We will test the wider applicability of emerging findings with a wider community using an
interpretative forum.
Discussion: The idea that collaboration between academics and services might lead to more applicable health
research that is actually used in practice is theoretically and intuitively appealing; however the evidence for it is
limited. Our evaluation is designed to capture the processes and impacts of collaborative approaches for
implementing research, and therefore should contribute to the evidence base about an increasingly popular (e.g.,
Mode two, integrated knowledge transfer, interactive research), but poorly understood approach to knowledge
translation. Additionally we hope to develop approaches for evaluating implementation processes and impacts
particularly with respect to integrated stakeholder involvement
Administrative Managers – A Critical Link
Institutional responses to changes in the higher education environment have caused movements in the roles and identities of administrative managers in UK universities. These shifts have highlighted the problem for individuals of balancing traditional public service considerations of administration with institutional innovation and development. Administrative managers find themselves not only acting as independent arbiters, giving impartial advice on the basis of professional expertise, but also becoming involved in political judgements about institutional futures. They increasingly undertake an interpretive function between the various communities of the university and its external partners. As the boundaries of the university have become more permeable, administrative and academic management have inter-digitated, and hybrid roles have developed. In undertaking increasingly complex functions, therefore, administrative managers play a critical role in linking the academic and executive arms of governance in the university
Residual ground-water levels of the neonicotinoid thiacloprid perturb chemosensing of Caenorhabditis elegans
© 2017, The Author(s). This study investigated the neurological effects of residual ground-water levels of thiaclopridon the non-target organism Caenorhabditis elegans. Nematodes treated with thiacloprid showed a dose-dependent and significantly increased twitch response at concentrations above 50 ng mL−1 that disabled their forward locomotion in liquid culture. In comparison with untreated controls, 10 ng mL−1 thiacloprid perturbed the chemosensory ability of C. elegans such that the nematodes no longer demonstrated positive chemotaxis towards a NaCl chemo-attractant, reducing their chemotaxis index from +0.48 to near to zero. Nematodes also exhibited a locomotion characteristic of those devoid of chemo-attraction, making significantly more pirouetting turns of ≥90° than the untreated controls. Compared to the untreated controls, expression of the endocytosis-associated gene, Rab-10, was also increased in C. elegans that had developed to adulthood in the presence of 10 ng mL−1 thiacloprid, suggesting their active engagement in increased recycling of affected cellular components, such as their nAChRs. Thus, even residual, low levels of this less potent neonicotinoid that may be found in field ground-water had measurable effects on a beneficial soil organism which may have environmental and ecological implications that are currently poorly understood
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