2,427 research outputs found
Association of the AFF3 gene and IL2/IL21 gene region with juvenile idiopathic arthritis
Recent genetic studies have led to identification of numerous loci that are associated with susceptibility to autoimmune diseases. The strategy of using information from these studies has facilitated the identification of novel juvenile idiopathic arthritis (JIA) susceptibility loci, specifically, PTPN22 and IL2RA. Several novel autoimmune susceptibility loci have recently been identified, and we hypothesise that single-nucleotide polymorphisms (SNPs) within these genes may also be JIA susceptibility loci. Five SNPs within the genes AFF3, IL2/IL21, IL7R, CTLA4 and CD226, previously associated with multiple autoimmune diseases were genotyped, in a large data set of Caucasian JIA patients and controls, and tested for association with JIA. We identified two susceptibility loci for JIA, AFF3 and the IL2/IL21 region and additional weak evidence supporting an association with the CTLA4 and IL7R genes, which warrant further investigation. All results require validation in independent JIA data sets. Further characterisation of the specific causal variants will be required before functional studies can be performed
Quantum radiation in a plane cavity with moving mirrors
We consider the electromagnetic vacuum field inside a perfect plane cavity
with moving mirrors, in the nonrelativistic approximation. We show that low
frequency photons are generated in pairs that satisfy simple properties
associated to the plane geometry. We calculate the photon generation rates for
each polarization as functions of the mechanical frequency by two independent
methods: on one hand from the analysis of the boundary conditions for moving
mirrors and with the aid of Green functions; and on the other hand by an
effective Hamiltonian approach. The angular and frequency spectra are discrete,
and emission rates for each allowed angular direction are obtained. We discuss
the dependence of the generation rates on the cavity length and show that the
effect is enhanced for short cavity lengths. We also compute the dissipative
force on the moving mirrors and show that it is related to the total radiated
energy as predicted by energy conservation.Comment: 17 pages, 1 figure, published in Physical Review
Association of the CCR5 gene with juvenile idiopathic arthritis
The CC chemokine receptor 5 (CCR5) has been shown to be important in the recruitment of T-helper cells to the synovium, where they accumulate, drive the inflammatory process and the consequent synovitis and joint destruction. A 32 base-pair insertion/deletion variant (CCR5Δ32) within the gene leads to a frame shift and a nonfunctional receptor. CCR5Δ32 has been investigated for its association with juvenile idiopathic arthritis (JIA), with conflicting results. The aim of this study was to investigate whether CCR5Δ32 is associated with JIA in an UK population. CCR5Δ32 was genotyped in JIA cases (n=1054) and healthy controls (n=3129) and genotype and allele frequencies were compared. A meta-analysis of our study combined with previously published studies was performed. CCR5Δ32 was significantly associated with protection from developing JIA, in this UK data set (P(trend)=0.006, odds ratio (OR) 0.79 95% confidence interval (95% CI): 0.66-0.94). The meta-analysis of all published case-control association studies confirmed the protective association with JIA (P=0.001 OR 0.82 95% CI: 0.73-0.93). CCR5Δ32 is a functional variant determining the number of receptors on the surface of T cells, and it is hypothesized that the level of CCR5 expression could influence the migration of proinflammatory T cells into the synovium and thus susceptibility to JIA
Ghost Busting: PT-Symmetric Interpretation of the Lee Model
The Lee model was introduced in the 1950s as an elementary quantum field
theory in which mass, wave function, and charge renormalization could be
carried out exactly. In early studies of this model it was found that there is
a critical value of g^2, the square of the renormalized coupling constant,
above which g_0^2, the square of the unrenormalized coupling constant, is
negative. Thus, for g^2 larger than this critical value, the Hamiltonian of the
Lee model becomes non-Hermitian. It was also discovered that in this
non-Hermitian regime a new state appears whose norm is negative. This state is
called a ghost state. It has always been assumed that in this ghost regime the
Lee model is an unacceptable quantum theory because unitarity appears to be
violated. However, in this regime while the Hamiltonian is not Hermitian, it
does possess PT symmetry. It has recently been discovered that a non-Hermitian
Hamiltonian having PT symmetry may define a quantum theory that is unitary. The
proof of unitarity requires the construction of a new time-independent operator
called C. In terms of C one can define a new inner product with respect to
which the norms of the states in the Hilbert space are positive. Furthermore,
it has been shown that time evolution in such a theory is unitary. In this
paper the C operator for the Lee model in the ghost regime is constructed
exactly in the V/N-theta sector. It is then shown that the ghost state has a
positive norm and that the Lee model is an acceptable unitary quantum field
theory for all values of g^2.Comment: 20 pages, 9 figure
Stimulating the innovation potential of 'routine' workers through workplace learning
Governments worldwide seek to upgrade the ‘basic skills' of employees deemed to have low literacy and numeracy, in order to enable their greater productivity and participation in workplace practices. A longitudinal investigation of such interventions in the United Kingdom has examined the effects on employees and on organizations of engaging in basic skills programmes offered in and through the workplace. ‘Tracking’ of employees in selected organizational contexts has highlighted ways in which interplay between formal and informal workplace learning can help to create the environments for employees in lower grade jobs to use and expand their skills. This workplace learning is a precondition, a stimulus and an essential ingredient for participation in employee-driven innovation, as workers engage with others to vary, and eventually to change, work practices. © 2010, SAGE Publications. All rights reserved
Effect of Native American ancestry on iron-related phenotypes of Alabama hemochromatosis probands with HFE C282Y homozygosity
BACKGROUND: In age-matched cohorts of screening study participants recruited from primary care clinics, mean serum transferrin saturation values were significantly lower and mean serum ferritin concentrations were significantly higher in Native Americans than in whites. Twenty-eight percent of 80 Alabama white hemochromatosis probands with HFE C282Y homozygosity previously reported having Native American ancestry, but the possible effect of this ancestry on hemochromatosis phenotypes was unknown. METHODS: We compiled observations in these 80 probands and used univariate and multivariate methods to analyze associations of age, sex, Native American ancestry (as a dichotomous variable), report of ethanol consumption (as a dichotomous variable), percentage transferrin saturation and log(e )serum ferritin concentration at diagnosis, quantities of iron removed by phlebotomy to achieve iron depletion, and quantities of excess iron removed by phlebotomy. RESULTS: In a univariate analysis in which probands were grouped by sex, there were no significant differences in reports of ethanol consumption, transferrin saturation, log(e )serum ferritin concentration, quantities of iron removed to achieve iron depletion, and quantities of excess iron removed by phlebotomy in probands who reported Native American ancestry than in those who did not. In multivariate analyses, transferrin saturation (as a dependent variable) was not significantly associated with any of the available variables, including reports of Native American ancestry and ethanol consumption. The independent variable quantities of excess iron removed by phlebotomy was significantly associated with log(e )serum ferritin used as a dependent variable (p < 0.0001), but not with reports of Native American ancestry or reports of ethanol consumption. Log(e )serum ferritin was the only independent variable significantly associated with quantities of excess iron removed by phlebotomy used as a dependent variable (p < 0.0001) (p < 0.0001; ANOVA of regression). CONCLUSION: We conclude that the iron-related phenotypes of hemochromatosis probands with HFE C282Y homozygosity are similar in those with and without Native American ancestry reports
Association of the AFF3 gene and IL2/IL21 gene region with juvenile idiopathic arthritis
Recent genetic studies have led to identification of numerous loci that are associated with susceptibility to autoimmune diseases. The strategy of using information from these studies has facilitated the identification of novel juvenile idiopathic arthritis (JIA) susceptibility loci, specifically, PTPN22 and IL2RA. Several novel autoimmune susceptibility loci have recently been identified, and we hypothesise that single-nucleotide polymorphisms (SNPs) within these genes may also be JIA susceptibility loci. Five SNPs within the genes AFF3, IL2/IL21, IL7R, CTLA4 and CD226, previously associated with multiple autoimmune diseases were genotyped, in a large data set of Caucasian JIA patients and controls, and tested for association with JIA. We identified two susceptibility loci for JIA, AFF3 and the IL2/IL21 region and additional weak evidence supporting an association with the CTLA4 and IL7R genes, which warrant further investigation. All results require validation in independent JIA data sets. Further characterisation of the specific causal variants will be required before functional studies can be performed
Schools and civil society : corporate or community governance
School improvement depends upon mediating the cultural conditions of learning as young people journey between their parochial worlds and the public world of cosmopolitan society. Governing bodies have a crucial role in including or diminishing the representation of different cultural traditions and in enabling or frustrating the expression of voice and deliberation of differences whose resolution is central to the mediation of and responsiveness to learning needs. A recent study of governing bodies in England and Wales argues that the trend to corporatising school governance will diminish the capacity of schools to learn how they can understand cultural traditions and accommodate them in their curricula and teaching strategies. A democratic, stakeholder model remains crucial to the effective practice of governing schools. By deliberating and reconciling social and cultural differences, governance constitutes the practices for mediating particular and cosmopolitan worlds and thus the conditions for engaging young people in their learning, as well as in the preparation for citizenship in civil society
Slogging and Stumbling Toward Social Justice in a Private Elementary School: The Complicated Case of St. Malachy
This case study examines St. Malachy, an urban Catholic elementary school primarily serving children traditionally marginalized by race, class, linguistic heritage, and disability. As a private school, St. Malachy serves the public good by recruiting and retaining such traditionally marginalized students. As empirical studies involving Catholic schools frequently juxtapose them with public schools, the author presents this examination from a different tack. Neither vilifying nor glorifying Catholic schooling, this study critically examines the pursuit of social justice in this school context. Data gathered through a 1-year study show that formal and informal leaders in St. Malachy adapted their governance, aggressively sought community resources, and focused their professional development to build the capacity to serve their increasingly pluralistic student population. The analysis confirms the deepening realization that striving toward social justice is a messy, contradictory, and complicated pursuit, and that schools in both public and private sectors are allies in this pursuit
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