1,648 research outputs found
LiftUpp: Support to Develop Learner Performance
Various motivations exist to move away from the simple assessment of
knowledge towards the more complex assessment and development of competence.
However, to accommodate such a change, high demands are put on the supporting
e-infrastructure in terms of intelligently collecting and analysing data. In
this paper, we discuss these challenges and how they are being addressed by
LiftUpp, a system that is now used in 70% of UK dental schools, and is finding
wider applications in physiotherapy, medicine and veterinary science. We
describe how data is collected for workplace-based development in dentistry
using a dedicated iPad app, which enables an integrated approach to linking and
assessing work flows, skills and learning outcomes. Furthermore, we detail how
the various forms of collected data can be fused, visualized and integrated
with conventional forms of assessment. This enables curriculum integration,
improved real-time student feedback, support for administration, and informed
instructional planning. Together these facets contribute to better support for
the development of learners' competence in situated learning setting, as well
as an improved experience. Finally, we discuss several directions for future
research on intelligent teaching systems that are afforded by using the design
present within LiftUpp.Comment: Short 4-page version to appear at AIED 201
Supersymmetric Higgs Yukawa Couplings to Bottom Quarks at next-to-next-to-leading Order
The effective bottom Yukawa couplings are analyzed for the minimal
supersymmetric extension of the Standard Model at two-loop accuracy within
SUSY-QCD. They include the resummation of the dominant corrections for large
values of tg(beta). In particular the two-loop SUSY-QCD corrections to the
leading SUSY-QCD and top-induced SUSY-electroweak contributions are addressed.
The residual theoretical uncertainties range at the per-cent level.Comment: 25 pages, 9 figures, added comments and references, typos corrected,
results unchanged, published versio
On the methodological unification in electroencephalography
BACKGROUND: This paper presents results of a pursuit of a repeatable and objective methodology of analysis of the electroencephalographic (EEG) time series. METHODS: Adaptive time-frequency approximations of EEG are discussed in the light of the available experimental and theoretical evidence, and applicability in various experimental and clinical setups. RESULTS: Four lemmas and three conjectures support the following conclusion. CONCLUSION: Adaptive time-frequency approximations of signals unify most of the univariate computational approaches to EEG analysis, and offer compatibility with its traditional (visual) analysis, used in clinical applications
A next-to-next-to-leading order calculation of soft-virtual cross sections
We compute the next-to-next-to-leading order (NNLO) soft and virtual QCD
corrections for the partonic cross section of colourless-final state processes
in hadronic collisions. The results are valid to all orders in the dimensional
regularization parameter \ep. The dependence of the results on a particular
process is given through finite contributions to the one and two-loop
amplitudes. To evaluate the accuracy of the soft-virtual approximation we
compare it with the full NNLO result for Drell-Yan and Higgs boson production
via gluon fusion. We also provide a universal expression for the hard
coefficient needed to perform threshold resummation up to
next-to-next-to-leading logarithmic (NNLL) accuracy.Comment: 25 pages, 4 figure
NLL+NNLO predictions for jet-veto efficiencies in Higgs-boson and Drell-Yan production
Using the technology of the CAESAR approach to resummation, we examine the
jet-veto efficiency in Higgs-boson and Drell-Yan production at hadron colliders
and show that at next-to-leading logarithmic (NLL) accuracy the resummation
reduces to just a Sudakov form factor. Matching with NNLO calculations results
in stable predictions for the case of Drell-Yan production, but reveals
substantial uncertainties in gluon-fusion Higgs production, connected in part
with the poor behaviour of the perturbative series for the total cross section.
We compare our results to those from POWHEG with and without reweighting by
HqT, as used experimentally, and observe acceptable agreement. In an appendix
we derive the part of the NNLL resummation corrections associated with the
radius dependence of the jet algorithm.Comment: 30 pages, 8 figures; v2 as published in JHE
Agent based modelling helps in understanding the rules by which fibroblasts support keratinocyte colony formation
Background: Autologous keratincoytes are routinely expanded using irradiated mouse fibroblasts and bovine serum for clinical use. With growing concerns about the safety of these xenobiotic materials, it is desirable to culture keratinocytes in media without animal derived products. An improved understanding of epithelial/mesenchymal interactions could assist in this.
Methodology/Principal Findings: A keratincyte/fibroblast o-culture model was developed by extending an agent-based keratinocyte colony formation model to include the response of keratinocytes to both fibroblasts and serum. The model was validated by comparison of the in virtuo and in vitro multicellular behaviour of keratinocytes and fibroblasts in single and co-culture in Greens medium. To test the robustness of the model, several properties of the fibroblasts were changed to investigate their influence on the multicellular morphogenesis of keratinocyes and fibroblasts. The model was then used to generate hypotheses to explore the interactions of both proliferative and growth arrested fibroblasts with keratinocytes. The key predictions arising from the model which were confirmed by in vitro experiments were that 1) the ratio of fibroblasts to keratinocytes would critically influence keratinocyte colony expansion, 2) this ratio needed to be optimum at the beginning of the co-culture, 3) proliferative fibroblasts would be more effective than irradiated cells in expanding keratinocytes and 4) in the presence of an adequate number of fibroblasts, keratinocyte expansion would be independent of serum.
Conclusions: A closely associated computational and biological approach is a powerful tool for understanding complex biological systems such as the interactions between keratinocytes and fibroblasts. The key outcome of this study is the finding that the early addition of a critical ratio of proliferative fibroblasts can give rapid keratinocyte expansion without the use of irradiated mouse fibroblasts and bovine serum
NLO QCD corrections to top anti-top bottom anti-bottom production at the LHC: 2. full hadronic results
We present predictions for top anti-top bottom anti-bottom production at the
LHC in next-to-leading order QCD. The precise description of this background
process is a prerequisite to observe associated top anti-top Higgs production
in the Higgs -> bottom anti-bottom decay channel and to directly measure the
top-quark Yukawa coupling at the LHC. The leading-order cross section is
extremely sensitive to scale variations. We observe that the traditional scale
choice adopted in ATLAS simulations underestimates the top anti-top bottom
anti-bottom background by a factor two and introduce a new dynamical scale that
stabilizes the perturbative predictions. We study various kinematic
distributions and observe that the corrections have little impact on their
shapes if standard cuts are applied. In the regime of highly boosted Higgs
bosons, which offers better perspectives to observe the top anti-top Higgs
signal, we find significant distortions of the kinematic distributions. The
one-loop amplitudes are computed using process-independent algebraic
manipulations of Feynman diagrams and numerical tensor reduction. We find that
this approach provides very high numerical stability and CPU efficiency.Comment: 42 pages, LaTeX, 44 postscript figure
Renal Athersosclerotic reVascularization Evaluation (RAVE Study): Study protocol of a randomized trial [NCT00127738]
BACKGROUND: It is uncertain whether patients with renal vascular disease will have renal or mortality benefit from re-establishing renal blood flow with renal revascularization procedures. The RAVE study will compare renal revascularization to medical management for people with atherosclerotic renal vascular disease (ARVD) and the indication for revascularization. Patients will be assessed for the standard nephrology research outcomes of progression to doubling of creatinine, need for dialysis, and death, as well as other cardiovascular outcomes. We will also establish whether the use of a new inexpensive, simple and available ultrasound test, the renal resistance index (RRI), can identify patients with renal vascular disease who will not benefit from renal revascularization procedures[1]. METHODS/DESIGN: This single center randomized, parallel group, pilot study comparing renal revascularization with medical therapy alone will help establish an infrastructure and test the feasibility of answering this important question in clinical nephrology. The main outcome will be a composite of death, dialysis and doubling of creatinine. Knowledge from this study will be used to better understand the natural history of patients diagnosed with renal vascular disease in anticipation of a Canadian multicenter trial. Data collected from this study will also inform the Canadian Hypertension Education Program (CHEP) Clinical Practice Guidelines for the management of Renal and Renal Vascular Disease. The expectation is that this program for ARVD, will enable community based programs to implement a comprehensive guidelines based diagnostic and treatment program, help create an evidence based approach for the management of patients with this condition, and possibly reduce or halt the progression of kidney disease in these patients. DISCUSSION: Results from this study will determine the feasibility of a multicentered study for the management of renovascular disease
Metabolic characteristics and body composition in house finches: effects of seasonal acclimatization
House finches ( Carpodacus mexicanus ) from the introduced population in the eastern United States were examined to assess metabolic characteristics and aspects of body composition associated with seasonal acclimatization. Wild birds were captured during winter (January and February) and late spring (May and June) in southeastern Michigan. Standard metabolic rates did not differ seasonally, but cold-induced “peak” metabolic rate was 28% greater in winter than late spring. The capacity to maintain elevated metabolic rates during cold exposure (“thermogenic endurance”) increased significantly from an average of 26.1 to 101.3 min in late spring and winter, respectively. House finches captured in the late afternoon during winter had twice as much stored fat as those during late spring. Both the wet mass and lean dry mass of the pectoralis muscle, a primary shivering effector, were significantly greater during winter. The seasonal changes in peak metabolism and thermogenic endurance demonstrate the existence and magnitude of metabolic seasonal acclimatization in eastern house finches. Increased quantities of stored fat during winter appear to play a role in acclimatization, yet other physiological adjustments such as lipid mobilization and catabolism are also likely to be involved.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47132/1/360_2004_Article_BF00367313.pd
The Rossiter-McLaughlin effect in Exoplanet Research
The Rossiter-McLaughlin effect occurs during a planet's transit. It provides
the main means of measuring the sky-projected spin-orbit angle between a
planet's orbital plane, and its host star's equatorial plane. Observing the
Rossiter-McLaughlin effect is now a near routine procedure. It is an important
element in the orbital characterisation of transiting exoplanets. Measurements
of the spin-orbit angle have revealed a surprising diversity, far from the
placid, Kantian and Laplacian ideals, whereby planets form, and remain, on
orbital planes coincident with their star's equator. This chapter will review a
short history of the Rossiter-McLaughlin effect, how it is modelled, and will
summarise the current state of the field before describing other uses for a
spectroscopic transit, and alternative methods of measuring the spin-orbit
angle.Comment: Review to appear as a chapter in the "Handbook of Exoplanets", ed. H.
Deeg & J.A. Belmont
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