D-optimal designs for multiarm trials with dropouts.

Multiarm trials with follow-up on participants are commonly implemented to assess treatment effects on a population over the course of the studies. Dropout is an unavoidable issue especially when the duration of the multiarm study is long. Its impact is often ignored at the design stage, which may lead to less accurate statistical conclusions. We develop an optimal design framework for trials with repeated measurements, which takes potential dropouts into account, and we provide designs for linear mixed models where the presence of dropouts is noninformative and dependent on design variables. Our framework is illustrated through redesigning a clinical trial on Alzheimer's disease, whereby the benefits of our designs compared with standard designs are demonstrated through simulations.Grant codes MR∕N028171∕ and MC_UP_1302∕

Inversion of exciton level splitting in quantum dots

The demonstration of degeneracy of exciton spin states is an important step toward the production of entangled photon pairs from the biexciton cascade. We measure the fine structure of exciton and biexciton states for a large number of single InAs quantum dots in a GaAs matrix; the energetic splitting of the horizontally and vertically polarized components of the exciton doublet is shown to decrease as the exciton confinement decreases, crucially passing through zero and changing sign. Thermal annealing is shown to reduce the exciton confinement, thereby increasing the number of dots with splitting close to zero

Taking Account of the Actions of Others in Value-based Reasoning

Practical reasoning, reasoning about what actions should be chosen, is highly dependent both on the individual values of the agent concerned and on what others choose to do. Hitherto, computational models of value-based argumentation for practical reasoning have required assumptions to be made about the beliefs and preferences of other agents. Here we present a new method for taking the actions of others into account that does not require these assumptions: the only beliefs and preferences considered are those of the agent engaged in the reasoning. Our new formalism draws on utility-based approaches and expresses the reasoning in the form of arguments and objections, to enable full integration with value-based practical reasoning. We illustrate our approach by showing how value-based reasoning is modelled in two scenarios used in experimental economics, the Ultimatum Game and the Prisoner's Dilemma, and we present an evaluation of our approach in terms of these experiments. The evaluation demonstrates that our model is able to reproduce computationally the results of ethnographic experiments, serving as an encouraging validation exercise

On the role of mobility and interaction topologies in social dilemmas

Numerous studies have developed and analysed strategies for maximising utility in social dilemmas from both an individual agent's perspective and more generally from the viewpoint of a society. In this paper we bring this body of work together by investigating the success of a wide range of strategies in environments with varying characteristics, comparing their success. In particular we study within agent-based simulations, different interaction topologies, agents with and without mobility, and strategies with and without adaptation in the form of reinforcement learning, in both competitive and cooperative settings represented by the Prisoner's Dilemma and the Stag Hunt, respectively. The results of our experiments show that allowing agents mobility decreases the level of cooperation in the society of agents, due to singular interactions with individual opponents that limit the possibility for direct reciprocity. Unstructured environments similarly support a greater number of singular interactions and thus higher levels of defection in the Prisoner's Dilemma. In the Stag Hunt, strategies that prioritise risk taking show a greater level of success regardless of environment topology. Our range of experiments yield new insights into the role that mobility and interaction topologies play in the study of cooperation in agent societies

An exploration of alcohol advertising on social networking sites: an analysis of content, interactions and young people’s perspectives

Young people increasingly communicate and interact via social digital media such as Social Network Sites (SNS), where they discuss and display alcohol-related content. SNS have also become an important aspect of the alcohol industry’s multi-platform marketing strategies, which may contribute to the creation of intoxigenic digital spaces in which young people learn about alcohol. This paper presents findings of a content analysis of the extent, nature, and user interaction with SNS-based alcohol marketing for brands popular among young people in the UK. It provides a systematic analysis of both official and user generated marketing content on brand Facebook and Twitter profiles, and user interaction with such content. Findings from peer group interviews (N = 14) also present young people’s (N = 70) perspectives and experiences regarding alcohol marketing on SNS. New SNS engagement marketing strategies extended existing multi-platform brand marketing. Young people interacted with such strategies as part of their identity-making practices, yet through a discourse of immaturity distanced themselves from certain brands, online marketing practices and the idea that their own actions were influenced by marketing. Local night life economy marketing appeared more meaningful and relevant to young people and led to further interaction with brand marketing. Implications of the findings are discussed in relation to the influence of alcohol marketing on young people, and the implications for current regulatory frameworks

Antibodies to the Mr 64,000 (64K) protein in islet cell antibody positive non-diabetic individuals indicate high risk for impaired Beta-cell function

A prospective study of a normal childhood population identified 44 islet cell antibody positive individuals. These subjects were typed for HLA DR and DQ alleles and investigated for the presence of antibodies to the Mr 64,000 (64K) islet cell antigen, complement-fixing islet cell antibodies and radiobinding insulin autoantibodies to determine their potency in detecting subjects with impaired Beta-cell function. At initial testing 64K antibodies were found in six of 44 islet cell antibody positive subjects (13.6%). The same sera were also positive for complement-fixing islet cell antibodies and five of them had insulin autoantibodies. During the follow-up at 18 months, islet cell antibodies remained detectable in 50% of the subjects studied. In all six cases who were originally positive, 64K antibodies were persistently detectable, whereas complement-fixing islet cell antibodies became negative in two of six and insulin autoantibodies in one of five individuals. HLA DR4 (p < 0.005) and absence of asparic acid (Asp) at position 57 of the HLA DQ chain (p < 0.05) were significantly increased in subjects with 64K antibodies compared with control subjects. Of 40 individuals tested in the intravenous glucose tolerance test, three had a first phase insulin response below the first percentile of normal control subjects. Two children developed Type 1 (insulin-dependent) diabetes mellitus after 18 and 26 months, respectively. Each of these subjects was non-Asp homozygous and had persistent islet cell and 64K antibodies. We conclude that 64K antibodies, complement-fixing islet cell antibodies and insulin autoantibodies represent sensitive serological markers in assessing high risk for a progression to Type 1 diabetes in islet cell antibody positive non-diabetic individuals

Melaena with Peutz-Jeghers syndrome: a case report

Introduction: Peutz-Jeghers syndrome (PJS) is a rare familial disorder characterised by mucocutaneous pigmentation, gastrointestinal and extragastrointestinal hamartomatous polyps and an increased risk of malignancy. Peutz-Jeghers polyps in the bowel may result in intussusception. This complication usually manifests with abdominal pain and signs of intestinal obstruction. Case Presentation: We report the case of a 24-year-old Caucasian male who presented with melaena. Pigmentation of the buccal mucosa was noted but he was pain-free and examination of the abdomen was unremarkable. Upper gastrointestinal endoscopy revealed multiple polyps. An urgent abdominal computed tomography (CT) scan revealed multiple small bowel intussusceptions. Laparotomy was undertaken on our patient, reducing the intussusceptions and removing the polyps by enterotomies. Bowel resection was not needed. Conclusion: Melaena in PJS needs to be urgently investigated through a CT scan even in the absence of abdominal pain and when clinical examination of the abdomen shows normal findings. Although rare, the underlying cause could be intussusception, which if missed could result in grave consequences

Magazines as contradictory spaces for alcohol messaging: a mixed method content and thematic analysis of UK women’s magazine representations of alcohol and its consumption

Background: Women’s magazines provide a space in which gendered norms around alcohol-related practice are (re)-produced. They act as important points of reference for women to draw upon in their own understandings of alcohol use within their identity making. Studying the alcohol-related messages women’s magazines disseminate is therefore an important line of inquiry. Methods: An analysis of textual and visual alcohol depictions, including alcohol advertising, in 70 editions of 20 printed magazines targeted at and read by women, published between August 2020 and January 2021, was conducted using quantitative content and qualitative thematic analysis. Results: Women’s magazines have the potential to disseminate public health messages about the physical and mental health impacts of alcohol use, alcohol’s role in gender inequalities and the risk of harm from alcohol use by men. However, they do so in ways that reproduce harmful gender norms and expectations, and overlook the structural causes of alcohol-related harms. Associations between alcohol use and violence against women were simplified, in ways that ignored the root causes, produced victim-blaming narratives and deflected responsibility from the perpetrator to the effects of alcohol. Narratives around drinking and sobriety were underpinned by concerns over appearance, which reinforced social expectations of the ideal feminine body. Health narratives were in conflict with the presence of pro-alcohol messages such as consumption suggestions and alcohol advertising, which promoted alcohol use as a normalised aspect of women’s day to day lives. Conclusions: Women receive a number of mixed and contradictory messages on alcohol use through their magazine readership, which places limits on magazines as educational sources of public health messaging

Insulin autoantibodies as determined by competitive radiobinding assay are positively correlated with impaired beta-cell function — The Ulm-Frankfurt population study

Out of a random population of 4208 non-diabetic pupils without a family history of Type I diabetes 44 (1.05%) individuals had islet cell antibody (ICA) levels greater or equal to 5 Juvenile Diabetes Foundation (JDF) units. 39 of these ICA-positives could be repeatedly tested for circulating insulin autoantibodies (CIAA) using a competitive radiobinding assay. The results were compared with the insulin responses in the intravenous glucose tolerance tests (IVGTT) and with HLA types. Six pupils were positive for CIAA. All of them had complement-fixing ICA, and 5 of them were HLA-DR4 positive. Three of the 6 showed a first-phase insulin response below the first percentile of normal controls. Our data indicate that in population-based studies CIAA can be considered as a high risk marker for impaired beta-cell function in non-diabetic ICA-positive individuals