A TDDFT investigation of excited states of the Photosystem II Reaction Centre

A deeper understanding of the mechanisms involved in natural photosynthesis could inspire new artificial photosynthetic systems and bio-engineered organisms. Study of photosystem II, a pigment-protein complex responsible for the first step of solar energy conversion in oxygenic photosynthesis, is therefore driven by the need for clean energy and robust crops. Following excitation of the reaction centre of photosystem II, electron transfer proceeds selectively up one branch (the D1 branch) of the pseudo-C2-symmetric reaction centre producing a highly oxidative charge separated state, capable of abstracting electrons from substrate water. The structural reasons for the D1 branch preference are unclear, and remain difficult to probe due to the complexity of the system and its spectral features. Finding these will necessarily rely on detailed modelling, the challenge of which can finally be met with sufficient computational resource using Density Functional Theory. Results of Time Dependent Density Functional Theory calculations of excited states of the Photosystem II reaction centre are presented. It was found that pigment phytol chains and surrounding amino acid residues must be explicitly included in any model in order for the D1 branch preference to be reproduced. Building on this insight, results of calculations on mutant models of the same size are presented. A qualitative agreement with experimental shifts in simulated absorption difference spectra is achieved for seven out of ten mutant reaction centre models. Including further regions of the reaction centre was found to exaggerate the D1 branch preference further but overall larger models were in agreement with the benchmark model results. This work takes steps towards a working model of the reaction centre that could be used to investigate the individual structural features which lead to the D1 branch preference and as a predictive tool for the action of specific mutations.Open Acces

Young children as global citizens

The publication of Aistear, the Early Childhood Curriculum Framework (NCCA, 2009) provides a unique opportunity to promote the inclusion of a global and justice perspective in education programmes for young children at pre-school and junior primary school levels. The Framework highlights the importance of global citizenship and diversity issues and provides the opportunity to support educators engaged in their implementation. To facilitate the provision of such support, a partnership between Trócaire and St Patrick’s College, Drumcondra has undertaken research into young children’s engagement with issues of global justice. This article describes the background to the research, the methodologies used, and the research findings and dissemination

Sexual Functioning in Men With and Without Disabilities: Findings From a Representative Sample of Australian Men.

INTRODUCTION: Studies on sexual function in men with disabilities have mainly relied on clinical samples; population-based evidence on this topic is limited. AIM: The aim of this study was to compare aspects of sexual function between disabled and nondisabled men using a representative sample. METHODS: We used data from Ten to Men, a national cohort study of Australian men aged 18-55 years. We first compared the prevalence of 15 sexual function-related difficulties in disabled vs non-disabled men. Next, we used Poisson regression to examine associations between disability and sexual function. The main analytic sample had 8,496 men. Weights and adjustments appropriate to the sampling methodology were applied. Models adjusted for potential confounders. Results were reported as prevalence ratios (PRs). P values of 1.00 for disability; associations were statistically significant except "partner experienced sexual difficulties" (PR = 1.23; 95% CI = 0.99-1.53; P = .058) and "orgasmed too early" (PR = 1.16; 95% CI = 1.00-1.35; P = .050). "Presence of discomfort/pain" had the largest adjusted PR for disability (PR = 2.77; 95% CI = 1.89-4.06; P < .001). CLINICAL IMPLICATION: This population-based analysis on the relationship between disability and sexual function contextualizes evidence from clinical studies. Findings suggest that disparities between men with and without disability exist but are not uniform across different aspects of sexual function. STRENGTHS & LIMITATIONS: Two major strengths of this study are that the sample included a nondisabled reference group and results are generalizable to Australian men. A key limitation is that disability and sexual function measures are self-reported. CONCLUSION: This study provides a broad foundation of population-based evidence about sexual function in men with disabilities, relative to men without, showing positive associations between disability and 13 of 15 sexual difficulties. Bollier A-M, King T, Shakespeare T, et al. Sexual Functioning in Men With and Without Disabilities: Findings From a Representative Sample of Australian Men. J Sex Med 2019;16:1749-1757

WIMP particle physics and astrophysics with direct detection and neutrino telescope data

With positive signals from multiple direct detection experiments it will, in principle, be possi- ble to measure the mass and cross sections of weakly-interacting massive particle (WIMP) dark matter. Recent work has shown that, with a polynomial parameterisation of the WIMP speed dis- tribution, it is possible to make an unbiased measurement of the WIMP mass, without making any astrophysical assumptions. However, direct detection experiments are not sensitive to low-speed WIMPs and, therefore, any model-independent approach will lead to a bias in the cross section. This problem can be solved with the addition of measurements of the flux of neutrinos from the Sun. This is because the flux of neutrinos produced from the annihilation of WIMPs which have been gravitationally captured in the Sun is sensitive to low-speed WIMPs. Using mock data from next-generation direct detection experiments and from the IceCube neutrino telescope, we show that the complementary information from IceCube on low-speed WIMPs breaks the degeneracy between the cross section and the speed distribution. This allows unbiased determinations of the WIMP mass and spin-independent and spin-dependent cross sections to be made, and the speed distribution to be reconstructed. We use two parameterisations of the speed distribution: binned and polynomial. While the polynomial parameterisation can encompass a wider range of speed distributions, this leads to larger uncertainties in the particle physics parameters

Reduced food access due to a lack of money, inability to lift and lack of access to a car for food shopping : a multilevel study in Melbourne, Victoria

Objective: To describe associations between demographic and individual and arealevel socio-economic variables and restricted household food access due to lack of money, inability to lift groceries and lack of access to a car to do food shopping.Design: Multilevel study of three measures of restricted food access, i.e. running out of money to buy food, inability to lift groceries and lack of access to a car for food shopping. Multilevel logistic regression was conducted to examine the risk of each of these outcomes according to demographic and socio-economic variables.Setting: Random selection of households from fifty small areas in Melbourne, Australia, in 2003.Subjects: The main food shoppers in each household (n 2564).Results: A lack of money was significantly more likely among the young and in households with single adults. Difficultly lifting was more likely among the elderly and those born overseas. The youngest and highest age groups both reported reduced car access, as did those born overseas and single-adult households. All three factors were most likely among those with a lower individual or household socio-economic position. Increased levels of area disadvantage were independently associated with difficultly lifting and reduced car access.Conclusions: In Melbourne, households with lower individual socio-economic position and area disadvantage have restricted access to food because of a lack of money and/or having physical limitations due difficulty lifting or lack of access to a car for food shopping. Further research is required to explore the relationship between physical restrictions and food access.<br /

AN EMPIRICAL ANALYSIS OF MINIMUM GIFT AMOUNT FOR ATHLETIC FUNDRAISING ORGANIZATIONS IN NCAA DIVISION I

NCAA Division I college athletics departments are under pressure to generate greater revenue through donations, yet research related to strategic pricing structures of giving levels is underdeveloped. Tier rewards systems are a strategy designed to encourage donors to give specified amounts in exchange for benefits, such as access to football tickets and parking. The quantity and economic value of the incentives increase the more a donor gives. The purpose of this study is to examine the lowest tier giving level to determine: (a) the characteristics of this level and (b) to determine the relationship between key variables and both the minimum giving amount and number of donors at that level. Hierarchical regression was used to determine this relationship for athletic annual funds in Division I (n = 128). The number of donors at the lowest giving tier served as the dependent variable, while the minimum gift for membership served as the key independent variable. All other factors were control variables in the model. Results of the study suggest the number of full-time development staff, minimum gift amount at the lowest tier, and maximum gift amount at the lowest tier are statistically significant.Master of Art

Emerging models of intercultural education in Irish primary schools: a critical case study analysis

Taking account of the complex and fluid relationship that exists between social structures and human agency, this dissertation critically explores how intercultural education is conceptualised and practised by teachers and principals in three Irish primary schools. Adopting a whole school approach, it critically explores the models of intercultural education emerging in the schools and examines the extent to which selected variables (leadership, ethos, culture, curriculum, pedagogy, relations) support and determine these models. It also draws on the voice of students to illuminate aspects of teachers’ practice. A review of the literature indicates that while a small number of Irish studies (Bryan, 2008, 2009a, 2009b) have provided critical theoretical insights into intercultural education as conceptualised and practised at second level, no previously published Irish research has provided critical analysis of a whole school approach to intercultural education at primary level. Adopting a qualitative case study methodology grounded in critical ethnography, this study explores the whole school environments of three Irish primary schools. It employs the methods of semi-structured interviews, focus group interviews, observations and document analysis. The study’s empirical findings are integrated with concepts drawn from critical and poststructural social theories, including the theories of critical multiculturalism, transformative leadership theory, discourse theory and cultural reproduction theory. Findings indicate a predominance of weaker models of intercultural education ' underpinned by liberal ideology. However, elements of critical multicultural education underpinned by more radical ideologies are also evident. Analysis suggests that the three interrelated variables of power relations, patronage and ethos and school leadership are the most important factors in determining the models of intercultural education emerging in the three schools. Findings also indicate that a more traditional curricular approach may be preferable to the weak additive curricular approaches which appear to be endemic in many Irish primary schools. The data suggest that while well intentioned, teachers’ endeavours to include intercultural content in their lesson plans can sometimes do more to undermine than support migrant students’ sense of belonging and feelings of inclusion and nonmigrant students’ understandings of the “developing” world. Critical analysis of the three case study schools and the Intercultural Education Guidelines (IEGs) (NCCA, 2005) suggests that a re-conceptualisation of intercultural education is necessary in the Irish context if intercultural education is to realise its transformative potential. In this context, a justice and rights informed framework of critical intercultural education which foregrounds the principles of democracy, critical consciousness and equity is presented. It is argued that this framework has the capacity to transform inequitable school power relations, organisational structures, policies and practices