1,829 research outputs found
The Case for an All-Age Graduate Tax in England
Following the large increase in Higher Education (HE) tuition fees in 2012, together with later variations in the terms of repayment and the interest rate to be paid, new graduates are now leaving university with very heavy debt repayment obligations. These debts are both inequitable and difficult to sustain. Inequitable, because current and future generations of students are expected to pay for HE opportunities which previous generations of graduates received for free. Difficult to sustain, because three quarters of current student borrowers are not expected to be able to repay their loans in full before their outstanding debt is written off after 30 years, as provided for in the current loan system. The full extent of these underpayments is hard to predict. Hence, the long-term fiscal foundations of the income-contingent loan system are both uncertain and weak. This paper sets out a proposal for an all-age graduate tax which would have three key advantages compared to the present HE loan system. First, in the interests of intergenerational equity, this tax would be applied to all existing generations of graduates, not just to recent graduates who are expected to meet the onerous repayment obligations attached to nstudent loans. Second, graduate tax payments made by those earning over £21 000 would been lower at all levels of earnings, than are current annual loan repayments, and thus less burdensome on graduates. Third, an all-age graduate tax would contribute to government tax revenue from the first year that it was introduced, bringing substantially more revenue than the current level of loan repayments made to the Student Loans Company. It would thus provide a more secure fiscal foundation to HE finances than can be achieved through the present loan system. Furthermore, an all-age graduate tax could also provide a means of tackling the problem of accumulated loan debt incurred by recent graduates
An analytical study of the MHD clamshell instability on a sphere
This is the final version. Available on open access from Cambridge University Press via the DOI in this recordData access statement:
No data were created or analysed in this study.This paper studies the instability of two-dimensional magnetohydrodynamic (MHD) systems on a sphere using analytical methods. The underlying flow consists of a zonal differential rotation and a toroidal magnetic field is present. Semicircle rules that prescribe the possible domain of the wave velocity in the complex plane for general flow and field profiles are derived. The paper then sets out an analytical study of the `clamshell instability', which features field lines on the two hemispheres tilting in opposite directions (Cally 2001, Sol. Phys. vol. 199, pp. 231--249). An asymptotic solution for the instability problem is derived for the limit of weak shear of the zonal flow, via the method of matched asymptotic expansions. It is shown that when the zonal flow is solid body rotation, there exists a neutral mode that tilts the magnetic field lines, referred to as the `tilting mode'. A weak shear of the zonal flow excites the critical layer of the tilting mode, which reverses the tilting direction to form the clamshell pattern and induces the instability. The asymptotic solution provides insights into properties of the instability for a range of flow and field profiles. A remarkable feature is that the magnetic field affects the instability only through its local behaviour in the critical layer.Engineering and Physical Sciences Research Council (EPSRC
Contact Manifolds, Contact Instantons, and Twistor Geometry
Recently, Kallen and Zabzine computed the partition function of a twisted
supersymmetric Yang-Mills theory on the five-dimensional sphere using
localisation techniques. Key to their construction is a five-dimensional
generalisation of the instanton equation to which they refer as the contact
instanton equation. Subject of this article is the twistor construction of this
equation when formulated on K-contact manifolds and the discussion of its
integrability properties. We also present certain extensions to higher
dimensions and supersymmetric generalisations.Comment: v3: 28 pages, clarifications and references added, version to appear
in JHE
The Kinematic Algebra From the Self-Dual Sector
We identify a diffeomorphism Lie algebra in the self-dual sector of
Yang-Mills theory, and show that it determines the kinematic numerators of
tree-level MHV amplitudes in the full theory. These amplitudes can be computed
off-shell from Feynman diagrams with only cubic vertices, which are dressed
with the structure constants of both the Yang-Mills colour algebra and the
diffeomorphism algebra. Therefore, the latter algebra is the dual of the colour
algebra, in the sense suggested by the work of Bern, Carrasco and Johansson. We
further study perturbative gravity, both in the self-dual and in the MHV
sectors, finding that the kinematic numerators of the theory are the BCJ
squares of the Yang-Mills numerators.Comment: 29 pages, 5 figures. v2: references added, published versio
Risk of major cardiovascular events in patients with psoriasis receiving biologic therapies: a prospective cohort study.
BACKGROUND: The cardiovascular safety profile of biologic therapies used for psoriasis is unclear. OBJECTIVES: To compare the risk of major cardiovascular events (CVEs; acute coronary syndrome, unstable angina, myocardial infarction and stroke) in patients with chronic plaque psoriasis treated with adalimumab, etanercept or ustekinumab in a large prospective cohort. METHODS: Prospective cohort study examining the comparative risk of major CVEs was conducted using the British Association of Dermatologists Biologics and Immunomodulators Register. The main analysis compared adults with chronic plaque psoriasis receiving ustekinumab with tumour necrosis-α inhibitors (TNFi: etanercept and adalimumab), whilst the secondary analyses compared ustekinumab, etanercept or methotrexate against adalimumab. Hazard ratios (HRs) with 95% confidence intervals (CIs) were calculated using overlap weights by propensity score to balance baseline covariates among comparison groups. RESULTS: We included 5468 biologic-naïve patients subsequently exposed (951 ustekinumab; 1313 etanercept; and 3204 adalimumab) in the main analysis. The secondary analyses also included 2189 patients receiving methotrexate. The median (p25-p75) follow-up times for patients using ustekinumab, TNFi, adalimumab, etanercept and methotrexate were as follows: 2.01 (1.16-3.21), 1.93 (1.05-3.34), 1.94 (1.09-3.32), 1.92 (0.93-3.45) and 1.43 (0.84-2.53) years, respectively. Ustekinumab, TNFi, adalimumab, etanercept and methotrexate groups had 7, 29, 23, 6 and 9 patients experiencing major CVEs, respectively. No differences in the risk of major CVEs were observed between biologic therapies [adjusted HR for ustekinumab vs. TNFi: 0.96 (95% CI 0.41-2.22); ustekinumab vs. adalimumab: 0.81 (0.30-2.17); etanercept vs. adalimumab: 0.81 (0.28-2.30)] and methotrexate against adalimumab [1.05 (0.34-3.28)]. CONCLUSIONS: In this large prospective cohort study, we found no significant differences in the risk of major CVEs between three different biologic therapies and methotrexate. Additional studies, with longer term follow-up, are needed to investigate the potential effects of biologic therapies on incidence of major CVEs
Connective Tissue Growth Factor (Ctgf) Is a Critical Mediator of Cryoglobulinaemic Vasculitis (Cv) and a Novel Target for Therapy
A standardization approach to compare treatment safety and effectiveness outcomes between clinical trials and real‐world populations in psoriasis
Background:
Patients recruited in randomized controlled trials (RCTs) for biologic therapies in psoriasis are not fully representative of the real‐world psoriasis population.
Objectives:
Firstly, to investigate whether patient characteristics are associated with being included in a psoriasis RCT. Secondly, to estimate the differences in the incidence of severe adverse events (SAEs) and the response rate between RCT and real‐world populations of patients on biologic therapies for psoriasis using a standardization method.
Methods:
Data from the British Association of Dermatologists Biologics and Immunomodulators Register (BADBIR) were appended to individual participant‐level data from two RCTs assessing ustekinumab in patients with psoriasis. Baseline variables were assessed for association of being in an RCT using a multivariable logistic regression model. Propensity score weights were derived to reweigh the registry population so that variables had the distribution of the trial population. We measured the C‐statistic of the model with trial status as the dependent variable, and the risk differences in the incidence rate of SAEs in the first year and Psoriasis Area and Severity Index (PASI) after 6 months in the BADBIR cohort before and after weighting.
Results:
In total 6790 registry and 2021 RCT participants were included. The multivariable logistic regression model had a C‐statistic of 0.82 [95% confidence interval (CI) 0.81–0.83]. The risk differences for the incidence rate of SAEs and the proportion of patients with PASI < 1.5 were 9.27 (95% CI −3.91–22.5) per 1000 person‐years and 0.95 (95% CI −1.98–4.15), respectively.
Conclusions:
Our results suggest that RCTs of biologic therapies in patients with psoriasis are not fully representative of the real‐world population, but this lack of external validity does not account for the efficacy–effectiveness gap
Prescribing practices of primary-care veterinary practitioners in dogs diagnosed with bacterial pyoderma
Concern has been raised regarding the potential contributions of veterinary antimicrobial use to increasing levels of resistance in bacteria critically important to human health. Canine pyoderma is a frequent, often recurrent diagnosis in pet dogs, usually attributable to secondary bacterial infection of the skin. Lesions can range in severity based on the location, total area and depth of tissue affected and antimicrobial therapy is recommended for resolution. This study aimed to describe patient signalment, disease characteristics and treatment prescribed in a large number of UK, primary-care canine pyoderma cases and to estimate pyoderma prevalence in the UK vet-visiting canine population
Spin-orbit density wave induced hidden topological order in URu2Si2
The conventional order parameters in quantum matters are often characterized
by 'spontaneous' broken symmetries. However, sometimes the broken symmetries
may blend with the invariant symmetries to lead to mysterious emergent phases.
The heavy fermion metal URu2Si2 is one such example, where the order parameter
responsible for a second-order phase transition at Th = 17.5 K has remained a
long-standing mystery. Here we propose via ab-initio calculation and effective
model that a novel spin-orbit density wave in the f-states is responsible for
the hidden-order phase in URu2Si2. The staggered spin-orbit order 'spontaneous'
breaks rotational, and translational symmetries while time-reversal symmetry
remains intact. Thus it is immune to pressure, but can be destroyed by magnetic
field even at T = 0 K, that means at a quantum critical point. We compute
topological index of the order parameter to show that the hidden order is
topologically invariant. Finally, some verifiable predictions are presented.Comment: (v2) Substantially modified from v1, more calculation and comparison
with experiments are include
Yangian in the Twistor String
We study symmetries of the quantized open twistor string. In addition to
global PSL(4|4) symmetry, we find non-local conserved currents. The associated
non-local charges lead to Ward identities which show that these charges
annihilate the string gluon tree amplitudes, and have the same form as
symmetries of amplitudes in N=4 super conformal Yang Mills theory. We describe
how states of the open twistor string form a realization of the PSL(4|4)
Yangian superalgebra.Comment: 37 pages, 4 figure
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