59,158 research outputs found
Accurately model the Kuramoto--Sivashinsky dynamics with holistic discretisation
We analyse the nonlinear Kuramoto--Sivashinsky equation to develop accurate
discretisations modeling its dynamics on coarse grids. The analysis is based
upon centre manifold theory so we are assured that the discretisation
accurately models the dynamics and may be constructed systematically. The
theory is applied after dividing the physical domain into small elements by
introducing isolating internal boundaries which are later removed.
Comprehensive numerical solutions and simulations show that the holistic
discretisations excellently reproduce the steady states and the dynamics of the
Kuramoto--Sivashinsky equation. The Kuramoto--Sivashinsky equation is used as
an example to show how holistic discretisation may be successfully applied to
fourth order, nonlinear, spatio-temporal dynamical systems. This novel centre
manifold approach is holistic in the sense that it treats the dynamical
equations as a whole, not just as the sum of separate terms.Comment: Without figures. See
http://www.sci.usq.edu.au/staff/aroberts/ksdoc.pdf to download a version with
the figure
Holistic finite differences accurately model the dynamics of the Kuramoto-Sivashinsky equation
We analyse the nonlinear Kuramoto-Sivashinsky equation to develop an accurate
finite difference approximation to its dynamics. The analysis is based upon
centre manifold theory so we are assured that the finite difference model
accurately models the dynamics and may be constructed systematically. The
theory is applied after dividing the physical domain into small elements by
introducing insulating internal boundaries which are later removed. The
Kuramoto-Sivashinsky equation is used as an example to show how holistic finite
differences may be applied to fourth order, nonlinear, spatio-temporal
dynamical systems. This novel centre manifold approach is holistic in the sense
that it treats the dynamical equations as a whole, not just as the sum of
separate terms
Incapacity Benefit: A Health or Labour Market Phenomenon?
The number of people claiming Incapacity Benefit has remained fairly constant in recent years at around 2.7 million (7% of the working age population), although the numbers have trebled since the 1970s when an earlier version of this benefit was available. In January 2006 the UK Government set the ambitious target of reducing the number of claimants by one million, or around 40% of the total, within the next decade. New initiatives will focus on increasing the number of people who remain in work and increasing the number leaving benefits and finding employment. This paper explores these two critical transitions using data from waves 5 to 13 of the British Household Panel Survey. We consider whether the moves onto and off benefit are driven by health status or whether labour market factors are also important. Our results show that while health, and in particular psychological health, is an important determinant of these transitions, other factors such as age, occupation and geographical location are also key explanatory factors. This suggests that a very broad range of policy measures will be required if the government is to meet its target
Linear degree growth in lattice equations
We conjecture recurrence relations satisfied by the degrees of some
linearizable lattice equations. This helps to prove linear growth of these
equations. We then use these recurrences to search for lattice equations that
have linear growth and hence are linearizable
Digital data averager improves conventional measurement system performance
Multipurpose digital averager provides measurement improvement in noisy signal environments. It provides increased measurement accuracy and resolution to basic instrumentation devices by an arithmetical process in real time. It is used with standard conventional measurement equipment and digital data printers
A zonal computational procedure adapted to the optimization of two-dimensional thrust augmentor inlets
A viscous-inviscid interaction methodology based on a zonal description of the flowfield is developed as a mean of predicting the performance of two-dimensional thrust augmenting ejectors. An inviscid zone comprising the irrotational flow about the device is patched together with a viscous zone containing the turbulent mixing flow. The inviscid region is computed by a higher order panel method, while an integral method is used for the description of the viscous part. A non-linear, constrained optimization study is undertaken for the design of the inlet region. In this study, the viscous-inviscid analysis is complemented with a boundary layer calculation to account for flow separation from the walls of the inlet region. The thrust-based Reynolds number as well as the free stream velocity are shown to be important parameters in the design of a thrust augmentor inlet
The effect of chemotherapeutic agents on telomere length maintenance in breast cancer cell lines
Copyright @ 2014 the authors. This article is made available through the Brunel Open Access Publishing Fund. It is distributed under the terms of the
Creative Commons Attribution Noncommercial License which permits
any noncommercial use, distribution, and reproduction in any
medium, provided the original author(s) and the source are credited.Mammalian telomeric DNA consists of tandem repeats of the sequence TTAGGG associated with a specialized set of proteins, known collectively as Shelterin. These telosomal proteins protect the ends of chromosomes against end-to-end fusion and degradation. Short telomeres in breast cancer cells confer telomere dysfunction and this can be related to Shelterin proteins and their level of expression in breast cancer cell lines. This study investigates whether expression of Shelterin and Shelterin-associated proteins are altered, and influence the protection and maintenance of telomeres, in breast cancer cells. 5-aza-2'-deoxycytidine (5-aza-CdR) and trichostatin A (TSA) were used in an attempt to reactivate the expression of silenced genes. Our studies have shown that Shelterin and Shelterin-associated genes were down-regulated in breast cancer cell lines; this may be due to epigenetic modification of DNA as the promoter region of POT1 was found to be partially methylated. Shelterin genes expression was up-regulated upon treatment of 21NT breast cancer cells with 5-aza-CdR and TSA. The telomere length of treated 21NT cells was measured by q-PCR showed an increase in telomere length at different time points. Our studies have shown that down-regulation of Shelterin genes is partially due to methylation in some epithelial breast cancer cell lines. Removal of epigenetic silencing results in up-regulation of Shelterin and Shelterin-associated genes which can then lead to telomere length elongation and stability
The Renal Lymphatics - an Important Fluid Transport System
Study of renal lymph fluid transport syste
An economic analysis of a pneumococcal vaccine programme in people aged over 64 years in a developed country setting.
BACKGROUND: Polysaccharide pneumococcal vaccination for older adults is being introduced in developed country settings. Evidence of protection by this vaccine against pneumococcal pneumonia, or confirmation that illness and death from bacteraemia are prevented, is currently limited. Decisions are often made based on partial information. We examined the policy implications by exploring the potential economic benefit to society and the health sector of pneumococcal vaccination in older adults. METHODS: A model to estimate the potential cost savings and cost-effectiveness of a polysaccharide pneumococcal vaccine programme was based on costs collected from patients, the literature, and routine health-services data. The effect of a pneumococcal vaccine (compared with no vaccination) was examined in a hypothetical cohort aged over 64 years. The duration of protection was assumed to be 10 years, with or without a booster at 5 years. RESULTS: If it were effective against morbidity from pneumococcal pneumonia, the main burden from pneumococcal disease, the vaccine could be cost-neutral to society or the health sector at low efficacy (28 and 37.5%, respectively, without boosting and with 70% coverage). If it were effective against morbidity from bacteraemia only, the vaccine's efficacy would need to be 75 and 89%, respectively. If protection against both morbidity and mortality from pneumococcal bacteraemia was 50%, the net cost to society would be 2500 pounds per year of life saved ( 3365 pounds from the health-sector perspective). Results were sensitive to incidence, case-fatality rates, and costs of illness. CONCLUSIONS: A vaccine with moderate efficacy against bacteraemic illness and death would be cost-effective. If it also protected against pneumonia, it would be cost-effective even if its efficacy were low
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