The in-plane linear elastic constants and out-of-plane bending of 3-coordinated ligament and cylinder-ligament honeycombs

Four novel cylinder-ligament honeycombs are described, where each cylinder has 3 tangentially-attached ligaments to form either a hexagonal or re-entrant hexagonal cellular network. The re-entrant cylinder-ligament honeycombs are reported for the first time. The in-plane linear elastic constants and out-of-plane bending response of these honeycombs are predicted using Finite Element (FE) modelling and comparison made with hexagonal and re-entrant hexagonal honeycombs without cylinders. A laser-crafted re-entrant cylinder-ligament honeycomb is manufactured and characterized to verify the FE model. The re-entrant honeycombs display negative Poisson's ratios and synclastic curvature upon out-of-plane bending. The hexagonal and 'trichiral' honeycombs possess positive Poisson's ratios and anticlastic curvature. The 'anti-trichiral' honeycomb (short ligament limit) displays negative Poisson's ratios when loaded in the plane of the honeycomb, but positive Poisson's ratio behaviour (anticlastic curvature) under out-of-plane bending. These responses are understood qualitatively through considering deformation occurs via direct ligament flexure and cylinder rotation-induced ligament flexure

The lifetime cost to English students of borrowing to invest in a medical degree:a gender comparison using data from the Office for National Statistics

OBJECTIVE: To evaluate this impact on male and female English medical graduates by estimating the total time and amount repaid on loans taken out with the UK's Student Loans Company (SLC). SETTING: UK. PARTICIPANTS: 4286 respondents with a medical degree in the Labour Force Surveys administered by the Office for National Statistics (ONS) between 1997 and 2014. OUTCOMES: Age-salary profiles were generated to estimate the repayment profiles for different levels of initial graduate debt. RESULTS: 2195 female and 2149 male medical graduates were interviewed by the ONS. Those working full-time (73.1% females and 96.1% males) were analysed in greater depth. Following standardisation to 2014 prices, average full-time male graduates earned up to 35% more than females by the age of 55. The initial graduate debt from tuition fees alone amounts to £39 945.69. Owing to interest charges on this debt the average full-time male graduate repays £57 303 over 20 years, while the average female earns less and so repays £61 809 over 26 years. When additional SLC loans are required for maintenance, the initial graduate debt can be as high as £81 916 and, as SLC debt is written off 30 years after graduation, the average female repays £75 786 while the average male repays £110 644. CONCLUSIONS: Medical graduates on an average salary are unlikely to repay their SLC debt in full. This is a consequence of higher university fees and as SLC debt is written off 30 years after graduation. This results in the average female graduate repaying more when debt is low, but a lower amount when debt is high compared to male graduates

Love, rights and solidarity: studying children's participation using Honneth's theory of recognition

Recent attempts to theorize children’s participation have drawn on a wide range of ideas, concepts and models from political and social theory. The aim of this article is to explore the specific usefulness of Honneth’s theory of a ‘struggle for recognition’ in thinking about this area of practice. The article identifies what is distinctive about Honneth’s theory of recognition, and how it differs from other theories of recognition. It then considers the relevance of Honneth’s conceptual framework to the social position of children, including those who may be involved in a variety of ‘participatory’ activities. It looks at how useful Honneth’s ideas are in direct engagement with young people’s praxis, drawing on ethnographic research with members of a children and young people’s forum. The article concludes by reflecting on the implications of this theoretical approach and the further questions which it opens up for theories of participation and of adult–child relations more generally

MOLECULAR APPROACHES FOR THE CHARACTERISATION OF GHANAIAN AVOCADO PEAR (PERSEA AMERICANA MILL.) GERMPLASM

ABSTRACT In forested regions of southern Ghana many edible forms of avocado pear exist, but offer different fruit and fruiting quality characteristics. This is the result of unregulated seed-based propagation, use of volunteer seedlings as planting materials by farmers and germplasm introductions from a variety of sources, including the USA by the United States Agency for International Development (USAID). It is believed that West Indian, Mexican and Guatemalan races of avocado all co-exist in Ghana. To date, no studies have been undertaken to characterise those races or their hybrids in Ghana. Some of the key determining morphological characteristics for those ecological races are outlined here. Research currently being carried out at the University of Nottingham, UK is investigating the use of molecular markers (AFLPs) to characterise and delineate the avocado pear germplasm currently grown in Ghana

Incompatibility Systems in Switchgrass

Switchgrass (Panicum virgatum L.), a cross-pollinated perennial, produces very little or no seed when self-pollinated, indicating the presence of self-incompatibility mechanisms. Knowledge of self-incompatibility mechanisms is required to use germplasm effectively in a breeding program. The objective of this study was to characterize features of the incompatibility systems in switchgrass. Seed set and seed characteristics of reciprocal matings of tetraploid, octaploid, and tetraploid x octaploid plants were used as measures of incompatibility. Both bagged mutual pollination and manual emasculation and pollination methods were used to make crosses. The percentages of self-compatibility in the tetraploid and octaploid parent plants were 0.35 and 1.39%, respectively. Prefertilization incompatibility in switchgrass is apparently under gametophytic control, since there were significant differences in percentage of compatible pollen as measured by percentage of total seed set between reciprocal matings within ploidy levels. Results indicated that the prefertilization incompatibility system in switchgrass is similar to the S-Z incompatibility system found in other members of the Poaceae. A postfertilization incompatibility system also exists that inhibits intermatings among octaploid and tetraploid plants. In these interploidy crosses, two very distinctive types of abnormal seed were found. When the female parent was the tetraploid plant, the resulting seed was small and shriveled, while when the female parent was the octaploid, small seed with floury endosperm was obtained. These results are similar to those obtained for endosperm incompatibility due to the endosperm balance number system found in other species

CD30-mediated signaling promotes the development of human T helper type 2-like T cells

We have recently shown that CD30, a member of the tumor necrosis factor/nerve growth factor receptor superfamily, is preferentially expressed by human T cell clones producing T helper (Th) type 2 cytokines. We report here that costimulation with an agonistic anti-CD30 monoclonal antibody enhanced antigen (Ag)-induced proliferation and cytokine secretion by established human Th2 and Th0 clones. Moreover, costimulation of peripheral blood mononuclear cells with the same anti-CD30 monoclonal antibody resulted in the preferential development of Ag-specific T cell lines and clones showing a Th2-like profile of cytokine secretion. In contrast, early blockade III bulk culture of CD30 ligand-CD30 interaction shifted the development of Ag-specific T cells towards the opposite (Th1-like) phenotype. Taken together, these data suggest that CD30 triggering of activated Th cells by CD30 ligand-expressing Ag-presenting cells may represent an important costimulatory signaling for the development of Th2-type responses

Modeling of negative Poisson’s ratio (auxetic) crystalline cellulose Iβ

Energy minimizations for unstretched and stretched cellulose models using an all-atom empirical force field (Molecular Mechanics) have been performed to investigate the mechanism for auxetic (negative Poisson’s ratio) response in crystalline cellulose Iβ from kraft cooked Norway spruce. An initial investigation to identify an appropriate force field led to a study of the structure and elastic constants from models employing the CVFF force field. Negative values of on-axis Poisson’s ratios nu31 and nu13 in the x1-x3 plane containing the chain direction (x3) were realized in energy minimizations employing a stress perpendicular to the hydrogen-bonded cellobiose sheets to simulate swelling in this direction due to the kraft cooking process. Energy minimizations of structural evolution due to stretching along the x3 chain direction of the ‘swollen’ (kraft cooked) model identified chain rotation about the chain axis combined with inextensible secondary bonds as the most likely mechanism for auxetic response

Ethical and methodological issues in engaging young people living in poverty with participatory research methods

This paper discusses the methodological and ethical issues arising from a project that focused on conducting a qualitative study using participatory techniques with children and young people living in disadvantage. The main aim of the study was to explore the impact of poverty on children and young people's access to public and private services. The paper is based on the author's perspective of the first stage of the fieldwork from the project. It discusses the ethical implications of involving children and young people in the research process, in particular issues relating to access and recruitment, the role of young people's advisory groups, use of visual data and collection of data in young people's homes. The paper also identifies some strategies for addressing the difficulties encountered in relation to each of these aspects and it considers the benefits of adopting participatory methods when conducting research with children and young people

Young children's research: children aged 4-8 years finding solutions at home and at school

Children's research capacities have become increasingly recognised by adults, yet children remain excluded from the academy, with reports of their research participation generally located in adults' agenda. Such practice restricts children's freedom to make choices in matters affecting them, underestimates children’s capabilities and denies children particular rights. The present paper reports on one aspect of a small-scale critical ethnographic study adopting a constructivist grounded approach to conceptualise ways in which children's naturalistic behaviours may be perceived as research. The study builds on multi-disciplinary theoretical perspectives, embracing 'new' sociology, psychology, economics, philosophy and early childhood education and care (ECEC). Research questions include: 'What is the nature of ECEC research?' and 'Do children’s enquiries count as research?' Initially, data were collected from the academy: professional researchers (n=14) confirmed 'finding solutions' as a research behaviour and indicated children aged 4-8 years, their practitioners and primary carers as 'theoretical sampling'. Consequently, multi-modal case studies were constructed with children (n=138) and their practitioners (n=17) in three ‘good’ schools, with selected children and their primary carers also participating at home. This paper reports on data emerging from children aged 4-8 years at school (n=17) and at home (n=5). Outcomes indicate that participating children found diverse solutions to diverse problems, some of which they set themselves. Some solutions engaged children in high order thinking, whilst others did not; selecting resources and trialing activities engaged children in 'finding solutions'. Conversely, when children's time, provocations and activities were directed by adults, the quality of their solutions was limited, they focused on pleasing adults and their motivation to propose solutions decreased. In this study, professional researchers recognised 'finding solutions' as research behaviour and children aged 4-8 years naturalistically presented with capacities for finding solutions; however, the children's encounters with adults affected the solutions they found

Sexual exploitation in children: Nature, prevalence and distinguishing characteristics reported in young adulthood

The aim of this study was to explore the nature and extent of sexual exploitation in a university student sample, whilst being clear that sexual exploitation is sexual abuse. Overall, 47% of participants (96 out of 204) reported having been approached by an adult in a sexual manner when they were under the age of 16. The study predicted that a number of individual characteristics would increase a young person’s vulnerability for sexual exploitation. These included low self-esteem, external locus of control, social loneliness and insecure attachment. Results indicated lower levels of self-esteem among those who had been approached sexually, although it is not clear in terms of causality. There were no differences in scores for locus of control or loneliness. Relationship anxiety was significantly linked with children having engaged in sexual behaviours with an adult. The implications of these findings are discussed in terms of emerging individual characteristics relating to a risk of sexual exploitation