9,885 research outputs found
Care Management of Patients With Complex Health Care Needs
Explores how patients' complexity of healthcare needs, vulnerability, and age affect the cost and quality of their health care. Examines the potential for care management to improve quality of care and reduce costs, elements of success, and challenges
The C291R Tau variant forms different types of protofibrils
Mutations in the MAPT gene can lead to disease-associated variants of tau. However, the pathological mechanisms behind these genetic tauopathies are poorly understood. Here, we characterized the aggregation stages and conformational changes of tau C291R, a recently described MAPT mutation with potential pathogenic functions. The C291R variant of the tau four-repeat domain (tau-K18; a functional fragment with increased aggregation propensity compared with the full-length protein), aggregated into a mix of granular oligomers, amorphous and annular pore-like aggregates, in native-state and heparin-treated reactions as observed using atomic force microscopy (AFM) and negative-stained electron microscopy. On extended incubation in the native-state, tau-K18 C291R oligomers, unlike wild type (WT) tau-K18, aggregated to form protofibrils of four different phenotypes: (1) spherical annular; (2) spherical annular encapsulating granular oligomers; (3) ring-like annular but non-spherical; and (4) linear protofibrils. The ring-like tau-K18 C291R aggregates shared key properties of annular protofibrils previously described for other amyloidogenic proteins, in addition to two unique features: irregular/non-spherical-shaped annular protofibrils, and spherical protofibrils encapsulating granular oligomers. Tau-K18 C291R monomers had a circular dichroism (CD) peak at ~210 nm compared with ~199 nm for tau-K18 WT. These data suggest mutation-enhanced β-sheet propensity. Together, we describe the characterization of tau-K18 C291R, the first genetic mutation substituting a cysteine residue. The aggregation mechanism of tau-K18 C291R appears to involve β-sheet-rich granular oligomers which rearrange to form unique protofibrillar structures
Tipping points near a delayed saddle node bifurcation with periodic forcing
We consider the effect on tipping from an additive periodic forcing in a
canonical model with a saddle node bifurcation and a slowly varying bifurcation
parameter. Here tipping refers to the dramatic change in dynamical behavior
characterized by a rapid transition away from a previously attracting state. In
the absence of the periodic forcing, it is well-known that a slowly varying
bifurcation parameter produces a delay in this transition, beyond the
bifurcation point for the static case. Using a multiple scales analysis, we
consider the effect of amplitude and frequency of the periodic forcing relative
to the drifting rate of the slowly varying bifurcation parameter.
We show that a high frequency oscillation drives an earlier tipping when the
bifurcation parameter varies more slowly, with the advance of the tipping point
proportional to the square of the ratio of amplitude to frequency. In the low
frequency case the position of the tipping point is affected by the frequency,
amplitude and phase of the oscillation. The results are based on an analysis of
the local concavity of the trajectory, used for low frequencies both of the
same order as the drifting rate of the bifurcation parameter and for low
frequencies larger than the drifting rate. The tipping point location is
advanced with increased amplitude of the periodic forcing, with critical
amplitudes where there are jumps in the location, yielding significant advances
in the tipping point. We demonstrate the analysis for two applications with
saddle node-type bifurcations
Creativity and Enquiry in Action: a case study of cross-curricular approaches in teacher education
The current Key Stage 3 National Curriculum for England orders that our education foster determination, adaptability, confidence, risk-taking, enterprise, creativity and enjoyment in a cross-curricular context in pupils. To appreciate these dimensions student teachers need to have multiple opportunities to experience such a curriculum for themselves. However, initial teacher education is an intense and demanding experience; student teachers veer between phases of basic survival and personal innovation as they develop their individual pedagogy and personal philosophy. For new secondary teachers their own subject specialism forms a core feature of their emerging professional identity and can act as a barrier to collaborative practice beyond that specialism. This paper discusses one example of a cross-curricular approach in which Art and Geography PGCE students reflect on their experiences of a collaborative event designed to break down subject barriers while exploiting the potential of subject specialism. Data collected from semi-structured interviews conducted with a sample of students during the two-day event is discussed. Data revealed that critical outcomes of the event included the practice and development of genuine collaboration, negotiation, teamwork, and leadership
Spin texture of generic helical edge states
We study the spin texture of a generic helical liquid, the edge modes of a
two-dimensional topological insulator with broken axial spin-symmetry. By
considering honeycomb and square lattice realizations of topological
insulators, we show that in all cases the generic behavior of a
momentum-dependent rotation of the spin quantization axis is realized. Here we
establish this mechanism also for disk geometries with continuous rotational
symmetry. Finally, we demonstrate that the rotation of spin-quantization axis
remains intact for arbitrary geometries, i.e. in the absence of any continuous
symmetry. We also calculate the dependence of this rotation on the model and
material parameters. Finally we propose a spectroscopy measurement which should
directly reveal the rotation of the spin-quantization axis of the helical edge
states.Comment: 16 pages, 17 figure
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Changing recycling behaviour: an evaluation of attitudes and behaviour to recycling in the Western Riverside area of London
Key to improving recycling performance in the UK is the need to more effectively engage the public and improve levels of participation. The research described in this paper combines quantitative and qualitative analysis of attitudinal and behavioural changes as part of an evaluation project to measure the impact of a multi-faceted waste awareness and education campaign in the Western Riverside Waste Authority area of central London. Analysis links attitudinal and behavioural responses to infrastructure provision and performance indicators for each area surveyed, as well as socio-demographic indicators. This paper presents the results and analysis of the attitudes, motivations and behaviours of a representative profile of households from this area of central London, in an attempt to better understand how behavioural change can be achieved and recycling targets met
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Developing Integrated Waste Management Systems: Information Needs and the Role of Locally Based Data
No abstract available
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