Oculomotor responses in emmetropia and myopia

It has been proposed that early-onset myopia (EOM) i.e. myopia onset before the age of 15 is primarily inherited whereas late-onset myopia (LOM) i.e. myopia onset after the age of 16 is induced by environmental factors, principally sustained near vision. No consensus exists as to which aspect of the near vision response; accommodation, vergence or their synergistic cross links promotes LOM development. Furthermore, the mechanism by which near vision could induce elongation of posterior chamber is obscure although there is evidence to show that ciliary muscle tone plays an important role. By comparing accommodation and vergence responses of emmetropes (EMMs), EOMs and LOMs under both open- and closed-loop conditions, this thesis aims to define further the oculomotor correlates of myopic development. A Canon Autoref R-1 optometer was used to measure accommodation responses while an Apple IIe controlled the flashed Maddox Rod sequence used when measuring vergence. Both techniques permitted open- and closed-loop measures to be obtained. The results presented demonstrate that it is unlikely that those individuals susceptible to LOM can be distinguished with regard to oculomotor responses or innervational characteristics of the ciliary muscle. The aetiology of LOM may be associated with ciliary muscle function but account needs to be taken of interactions between the ciliary muscle, choriod, sclera and introcular pressure and further research is necessary before those EMMs susceptible to LOM can be identified

NGOs, States, and Donors Revisited: Still Too Close for Comfort?

SummarySerious questions remain about the ability of NGOs to meet long-term transformative goals in their work for development and social justice. We investigate how, given their weak roots in civil society and the rising tide of technocracy that has swept through the world of foreign aid, most NGOs remain poorly placed to influence the real drivers of social change. However we also argue that NGOs can take advantage of their traditional strengths to build bridges between grassroots organizations and local and national-level structures and processes, applying their knowledge of local contexts to strengthen their roles in empowerment and social transformation

Nonuniqueness phenomena in discontinuous dynamical systems and their regularizations

In a recent paper by Guglielmi and Hairer (SIADS 2015), an analysis in the $\varepsilon\to 0$ limit was proposed of regularized discontinuous ODEs in codimension-2 switching domains; this was obtained by studying a certain 2-dimensional system describing the so-called hidden dynamics. In particular, the existence of a unique limit solution was not proved in all cases, a few of which were labeled as ambiguous, and it was not clear whether or not the ambiguity could be resolved. In this paper, we show that it cannot be resolved in general. A first contribution of this paper is an illustration of the dependence of the limit solution on the form of the switching function. Considering the parameter dependence in the ambiguous class of discontinuous systems, a second contribution is a bifurcation analysis, revealing a range of possible behaviors. Finally, we investigate the sensitivity of solutions in the transition from codimension-2 domains to codimension-3 when there is a limit cycle in the hidden dynamics.Comment: 32 pages, 5 figure

Interhemispheric coupling, the West Antarctic Ice Sheet and warm Antarctic interglacials

Ice core evidence indicates that even though atmospheric CO2 concentrations did not exceed 300 ppm at any point during the last 800 000 years, East Antarctica was at least 3–4 C warmer than preindustrial (CO2 280 ppm) in each of the last four interglacials. During the previous three interglacials, this anomalous warming was short lived (3000 years) and apparently occurred before the completion of Northern Hemisphere deglaciation. Hereafter, we refer to these periods as “Warmer than Present Transients” (WPTs). We present a series of experiments to investigate the impact of deglacial meltwater on the Atlantic Meridional Overturning Circulation (AMOC) and Antarctic temperature. It is well known that a slowed AMOC would increase southern sea surface temperature (SST) through the bipolar seesaw and observational data suggests that the AMOC remained weak throughout the terminations precedingWPTs, strengthening rapidly at a time which coincides closely with peak Antarctic temperature. We present two 800 kyr transient simulations using the Intermediate Complexity model GENIE-1 which demonstrate that meltwater forcing generates transient southern warming that is consistent with the timing of WPTs, but is not sufficient (in this single parameterisation) to reproduce the magnitude of observed warmth. In order to investigate model and boundary condition uncertainty, we present three ensembles of transient GENIE-1 simulations across Termination II (135 000 to 124 000 BP) and three snapshot HadCM3 simulations at 130 000 BP. Only with consideration of the possible feedback of West Antarctic Ice Sheet (WAIS) retreat does it become possible to simulate the magnitude of observed warming

Aortic calcification and femoral bone density are independently associated with left ventricular mass in patients with chronic kidney disease

Background Vascular calcification and reduced bone density are prevalent in chronic kidney disease and linked to increased cardiovascular risk. The mechanism is unknown. We assessed the relationship between vascular calcification, femoral bone density and left ventricular mass in patients with stage 3 non-diabetic chronic kidney disease in a cross-sectional observational study. Methodology and Principal Findings A total of 120 patients were recruited (54% male, mean age 55±14 years, mean glomerular filtration rate 50±13 ml/min/1.73 m2). Abdominal aortic calcification was assessed using lateral lumbar spine radiography and was present in 48%. Mean femoral Z-score measured using dual energy x-ray absorptiometry was 0.60±1.06. Cardiovascular magnetic resonance imaging was used to determine left ventricular mass. One patient had left ventricular hypertrophy. Subjects with aortic calcification had higher left ventricular mass compared to those without (56±16 vs. 48±12 g/m2, P = 0.002), as did patients with femoral Z-scores below zero (56±15 vs. 49±13 g/m2, P = 0.01). In univariate analysis presence of aortic calcification correlated with left ventricular mass (r = 0.32, P = 0.001); mean femoral Z-score inversely correlated with left ventricular mass (r = −0.28, P = 0.004). In a multivariate regression model that included presence of aortic calcification, mean femoral Z-score, gender and 24-hour systolic blood pressure, 46% of the variability in left ventricular mass was explained (P<0.001). Conclusions In patients with stage 3 non-diabetic chronic kidney disease, lower mean femoral Z-score and presence of aortic calcification are independently associated with increased left ventricular mass. Further research exploring the pathophysiology that underlies these relationships is warranted

Defining and characterising an endothelial microvesicle signature for improved detection of cardiovascular disease risk in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is associated with increased risk of cardiovascular disease; up to 50-fold in young women. Cardiovascular risk algorithms do not take SLE into account, nor are there biomarkers available to stratify patient risk. This project aimed to consider the role of endothelial microvesicles (EMVs) as biomarkers of cardiovascular risk and also as effectors through their miRNA content. To do so, EMVs were isolated and quantified from patient plasma by flow cytometry, before being correlated with QRISK cardiovascular risk scores and patient data. Key miRNAs were identified by data mining, and their abundance was determined in the vesicular fraction of patient plasma by quantitative PCR (qPCR). Thus an SLE miRNA panel was characterised. Finally, the effects of miRNA overexpression in endothelial cells were probed by developing miRNA constructs and lentiviral vectors through Gateway® cloning prior to functional tests. This revealed that patients with SLE demonstrated elevated QRISK3 scores, as well as markers of inflammation and cardiovascular risk, compared to controls. They were also found to have increased numbers of EMVs, which were further associated with cardiovascular risk. Five miRNAs were chosen to be studied and lentiviral vectors were successfully generated to model their overexpression. Of these, miR-126-3p was elevated in patients with an SLE flare, where it was associated with musculoskeletal symptoms, and caused a glycolytic shift when overexpressed in endothelial cells; miR-3148 was also elevated in SLE. MiR-93-5p, miR-320a and miR-30d-5p were reduced in SLE, but their overexpression resulted in impaired angiogenic tube formation in vitro, and they were associated with measures of fatigue in patients. This project supports the use of EMVs as biomarkers of cardiovascular risk in SLE, where they reflect disease activity and cardiovascular involvement. The identification of a miRNA panel further refines patient stratification and allows future identification of functional mechanisms and novel therapeutic targets

Experiences of support following a diagnosis of breast cancer

The literature review aimed to provide a greater understanding of male partners’ experiences of their female partner’s breast cancer. A comprehensive search for relevant qualitative studies was conducted which identified fourteen studies. The findings were synthesised using a meta-ethnography approach. Male partners were found to mirror the emotional reactions and responses of their partner’s and also found to manage difficult feelings by gathering information in order to re-establish balance within the family system. Providing male partners with information in accordance with their individual needs may help male partners meet the expectations of their role, reduce uncertainty and enable them to approach the diagnosis from a more informed position. The research paper aimed to explore the experience of friendships following a diagnosis of breast cancer. Using a qualitative design, ten women who had received a diagnosis of primary breast cancer were interviewed. Data were analysed using interpretative phenomenological analysis. Three super-ordinate themes were selected and discussed. The first theme explored ways in which breast cancer tested women’s expectations of their friendships, causing them to re-evaluate their quality and value; the second theme related to the importance of the proximity of their friends during the treatment phase of their illness; and the third described how time with friends post active treatment was re-evaluated based on the time and effort they had received from friends during their illness. Receiving a diagnosis of breast cancer therefore provided individuals with an opportunity to learn about the value and quality of their friendships. The critical appraisal reflects upon issues that arose while completing the research for this doctoral thesis. Obstacles and dilemmas faced during the different stages of the research process were discussed, the limitations of the research were explored and the potential implications for future research in this area were also considered

Chiral Symmetry restoration in the massive Thirring model at finite T and μ\mu: Dimensional reduction and the Coulomb gas

We show that in certain limits the (1+1)-dimensional massive Thirring model at finite temperature $T$ is equivalent to a one-dimensional Coulomb gas of charged particles at the same $T$. This equivalence is then used to explore the phase structure of the massive Thirring model. For strong coupling and $T>>m$ (the fermion mass) the system is shown to behave as a free gas of "molecules" (charge pairs in the Coulomb gas terminology) made of pairs of chiral condensates. This binding of chiral condensates is responsible for the restoration of chiral symmetry as $T\to\infty$. In addition, when a fermion chemical potential $\mu\neq 0$ is included, the analogy with a Coulomb gas still holds with $\mu$ playing the role of a purely imaginary external electric field. For small $T$ and $\mu$ we find a typical massive Fermi gas behaviour for the fermion density, whereas for large $\mu$ it shows chiral restoration by means of a vanishing effective fermion mass. Some similarities with the chiral properties of low-energy QCD at finite $T$ and baryon chemical potential are discussed.Comment: 28 pages, 6 figures, better resolution figures are available upon reques

Brave new brains: sociology, family and the politics of knowledge

This article critically explores sociological arguments for greater biosocial synthesis, centring contemporary developments in public policy to demonstrate how such a reframing of humanity tends to reinforce existing political orders and socially patterned normativities. The case for further amalgamation of the social and life sciences is examined to suggest that production of somatic markers of truth from relational encounters largely relies upon an anaemic and politically contained version of the social as acquired in early childhood. More specifically, the gendered, classed and culturally specific practice of parenting children has come to occupy a new significance in accounts of social brains and environmentally reactive genomes. This is highlighted through a discussion of ‘early intervention’ as a heavily biologized policy rationale framing opportunities for biosocial collaboration. It is argued that late capitalist objectives of personal investment and optimization are driving this assimilation of the social and life sciences, pursuing an agenda that traces and re-scores long-standing social divisions in the name of progress

Optimisation of the randomly amplified polymorphic DNA (RAPD) technique for the characterisation of selected South African maize (Zea mays L.) breeding material.

Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2000.Maize (Zea mays L.) is an important agronomic crop with the maize industry forming an important component of the South African economy. Considerable effort has been directed towards the genetic improvement of maize through both conventional breeding and biotechnology. Genotype identification by DNA fingerprinting is becoming an important activity in plant breeding. A widely used molecular based and relatively inexpensive method for DNA fingerprinting is the randomly amplified polymorphic DNA (RAPD) technique. The RAPD technique was tested in this study for its potential use in maize breeding programmes. Initial results using the technique showed a low degree of reproducibility, therefore both the DNA isolation and RAPD protocols were extensively optimised. DNA quality and quantity, and choice of Taq polymerase buffer were three of the variables found to be influential in ensuring reproducibility. The ability of the RAPD technique to characterise seven maize genotypes was evaluated. Sixty random oligonucleotide primers were screened. Forty two primers scored a total of 233 fragments (an average of 5.5 per primer), but not all primers gave reproducible profiles. Eighteen primers scored a total of 110 loci for the presence (1) and absence (0) of DNA fragments. RAPD markers were able to distinguish between all seven genotypes with five primers producing specific fragments for four genotypes. Genetic similarity matrices were calculated using two software programmes i.e. Genstat 5™ release 4.1 (1993) and PAUP (Phylogenetic Analysis Using Parsimony) 4.0 beta version (Swafford, 1998). Cluster analysis was used to generate dendrograms to visualise the genetic relationships of the seven maize genotypes (only minor differences were observed between the Genstat or PAUP method of analysis). Genetic diversity ranged from 0.62 to 0.96. The estimation of genetic relationship was in accordance with the presumed pedigree of the genotypes showing that the RAPD technique demonstrates potential for genome analysis of maize. The applicability of the technique for marker assisted selection was also evaluated. Near-isogenic lines (NILs) for leaf blight (Helminthosporium spp.) were screened for polymorphisms using a total of 120 primers. Ten primers identified polymorphisms between the NILs. Four primers produced five polymorphic fragments present in the resistant inbred K0315Y and absent in the susceptible inbred D0940Y. A small F2 population of 14 individuals was produced by selfing the F1 of a cross between K0315Y and D0940Y. To speed up the generation time, the F1 and F2 plants were cultured by embryo rescue from 18d old harvested seed. One fragment of 627 base pairs produced by primer OPB-01 (5' GTTTCGCTCC 3') showed a 3: 1 segregation in the small F2 population and was considered putatively linked to the HtN gene for leaf blight resistance. This study shows that the RAPD technique does have application in maize breeding programmes