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The importance Markov chain
No full textThe Importance Markov chain is a novel algorithm bridging the gap between rejection sampling and importance sampling, moving from one to the other through a tuning parameter. Based on a modified sample of an instrumental Markov chain targeting an instrumental distribution (typically via a MCMC kernel), the Importance Markov chain produces an extended Markov chain where the marginal distribution of the first component converges to the target distribution. For example, when targeting a multimodal distribution, the instrumental distribution can be chosen as a tempered version of the target which allows the algorithm to explore its modes more efficiently. We obtain a Law of Large Numbers and a Central Limit Theorem as well as geometric ergodicity for this extended kernel under mild assumptions on the instrumental kernel. Computationally, the algorithm is easy to implement and preexisting librairies can be used to sample from the instrumental distribution
Nemone Lethbridge’s play Baby Blues on BBC television: maternal mental illness narratives, stigma and support in 1970s Britain
Get PDFIn December 1973, the BBC aired Nemone Lethbridge’s auto-fictional play Baby Blues as one of their influential ‘Play for Today’ (PfT) series (1970–1984). This article explores the impact of Lethbridge’s controversial television play, which drew attention to taboo topics, such as infertility, caesarean section childbirth, infanticide, suicide, and, separately, motherhood ageism and dismissive medical professionals. It will illustrate how Lethbridge’s play Baby Blues was part of a broader change in discussing maternal mental illness and creating support for women experiencing postnatal depression and psychosis, instigated by the Women’s Liberation Movement (WLM). The article situates Baby Blues within the wider history of the PfT series, with its focus on socio-political issues, and highlights the challenges Lethbridge faced in bringing the play to production. It analyses the mixed responses to the play, many of which were critical, and how this led to Lethbridge’s launching of a grass-roots self-help group, Depressives Anonymous (DA), in 1974, which was—and still is—a long-lasting legacy of Baby Blues. The article builds on the history of maternal mental illness as explored in women’s narratives and its association with stigma, support and feminism, alongside the British Broadcasting Corporation’s television series PfT, in 1970s Britain
The use of sexual history evidence and 'sensitive private data' in Scottish rape and attempted rape trials
Get PDFRhodium(III) and iridium(III) pincer complexes of a neopentyl-substituted PNP pincer ligand which feature agostic interactions
Get PDFThe synthesis and characterization of five-coordinate rhodium(III) and iridium(III) complexes of the form [M(PNP-Np)(biph)][BArF4] are described, where PNP-Np is the neopentyl-substituted pincer ligand 2,6-(Np2PCH2)2C5H3N (Np = CH2tBu), biph = 2,2′-biphenyl, and ArF = 3,5-(CF3)2C6H3. These complexes are notable for the adoption of δ-agostic interactions in the solid state, as evidenced by X-ray crystallography (50–150 K) and ATR-IR spectroscopy, but are structurally dynamic in solution, exhibiting pseudorotation of the biph ligand on the 1H NMR time scale (185–308 K). The strength of the agostic interactions is discussed with reference to the known tert-butyl-substituted analogues [M(PNP-tBu)(biph)][BArF4], probed by reaction with carbon monoxide, and quantified computationally through NBO analysis, from which the conclusion is that 3-center–2-electron bonding increases in the order M = Ir > Rh (cf. 1.5× greater perturbation energy) and pincer ligand = PNP-Np > PNP-tBu (cf. 3.3× greater perturbation energy)
Common nutritional shortcomings in vegetarians and vegans
Get PDFThe popularity of vegetarian and vegan diets is growing due to increased awareness of the environmental and health benefits of such diets. However, despite the consumption of meatless diets being associated with decreased risk of chronic diseases and mortality, followers of these diets are prone to certain nutritional inadequacies, which could limit health benefits. The main nutrients of concern are vitamin B12, vitamin D, iodine, selenium, calcium, and iron. It is essential for all those following vegetarian and vegan diets to implement vitamin B12 supplementation. To prevent vitamin B12 deficiency, adults should take one oral dose of 50–100 μg cyanocobalamin daily or 2000 μg weekly divided into two oral cyanocobalamin doses. Iodine supplementation is essential for pregnant and breastfeeding women and is recommended for vegetarians and vegans who are unable to access sea vegetables or iodine-fortified foods. The recommended dose of iodine supplement for adults is 150 μg daily. Selenium supplementation should be reserved for individuals with clinical evidence of deficiency due to concerns of adverse effects on lipid profiles and type 2 diabetes risk. It is recommended that vegetarian and vegan adults should supplement 4000 International Units (IU)/d of oral vitamin D to prevent deficiency as sunlight exposure is unreliable due to a range of lifestyle and environmental factors. This recommendation also applies to omnivores. As a precaution, those wishing to transition to a more plant-based diet should consider how they will substitute the nutrition they currently obtain from animal-based foods with plant-based sources or appropriate supplementation
Militant democracy unmoored? The limits of constitutional analogy in international law
No full textAs constitutional democracies are faced with authoritarianism and other anti- constitutionalist threats, international law is seeing its own challenge from the increasing influence of authoritarian states. Yet, departing from the recent tendency to model the international legal order after constitutional governance, international lawyers seem to show little interest in the concept of militant democracy, while the latter lies at the centre of current debates surrounding constitutional self-defence. This paper aims to bring to light the current limits of constitutional analogy in international law through an investigation into the discrepancy between constitutional and international lawyers in responding to authoritarian co-optation. A three-pronged argument is submitted. First, in contrast to other appeals for constitutional self-defence, the concept of militant democracy is contentious where it stands in tension with the constitutional ethos. Second, while militant democracy as a constitutional concept presupposes a democratic and normative version of constitutional ordering, the absence of militant democracy on the international plane betrays the nondemocratic, albeit representative, character of the international legal order. Third, attempts to internationalize the concept of militant democracy should be rejected as an international version of militant democracy would only portend an (un)holy alliance of militant democracies and exacerbate the political division in international society. It is suggested that from out of a realignment of international law with the constitutional project of progress, a new constitutional analogy may emerge, giving fresh impetus to the realization of international law’s universal liberating promise
Towards a common European ethical and legal framework for conducting clinical research : the GATEKEEPER experience
Get PDFThis paper examines the ethical and legal challenges encountered during the GATEKEEPER Project and how these challenges informed the development of a comprehensive framework for future Large-Scale Pilot (LSP) projects. GATEKEEPER is a LSP Project with 48 partners conducting 30 implementation studies across Europe with 50,000 target participants grouped into 9 Reference Use Cases. The project underscored the complexity of obtaining ethical approval across various jurisdictions with divergent regulations and procedures. Through a detailed analysis of the issues faced and the strategies employed to navigate these challenges, this study proposes an ethical and legal framework. This framework, derived from a comparative analysis of ethical application forms and regulations, aims to streamline the ethical approval process for future LSP research projects. By addressing the hurdles encountered in GATEKEEPER, the proposed framework offers a roadmap for more efficient and effective project management, ensuring smoother implementation of similar projects in the future
Impact of formulation and slurry properties on lithium-ion electrode manufacturing
Get PDFThe characteristics and performance of lithium-ion batteries typically rely on the precise combination of materials in their component electrodes. Understanding the impact of this formulation and the interdependencies between each component is critical in optimising cell performance. Such optimisation is difficult as the cost and effort for the myriad of possible combinations is too high. This problem is addressed by combining a design of experiments (DoE) and advanced statistical machine learning approach with comprehensive experimental characterisation of electrode slurries and coatings. An industry relevant graphite anode system is used, and with the aid of DoE, less than 30 experiments are defined to map impact of different weight fractions of active material (80–96 wt%), conductive additive (Carbon Black at 1–10 wt%) and a two-component binder system (Carboxymethyl Cellulose (CMC) at 1–3 wt% and Styrene Butadiene Rubber (SBR), at 1–7 wt%). Using Explainable Machine Learning (XML) methods, correlations between the formulation, slurry weight percentage (30–50 wt% in water) and coating speed (1–15 m/min) are quantified. Slurry viscosity, while known to depend on the CMC concentration, is also heavily influenced by carbon black and SBR when at high concentration, as is common in research. Viscosity increasing components also improve adhesion, by improving dispersion and hindering binder migration. Conductivity of the coating on current collector is sensitive to the current collector-coating interface, which makes it a highly useful probe. Improvements in cell capacity are observed with higher viscosity formulations (High weight percentage, CMC content), attributed to reduction in migration and slumping of the slurry on the current collector. SBR had a negative impact at any concentration due to its insulating nature, and carbon black reduces gravimetric capacity when included at high concentrations. The insights from this study facilitate the formulation optimisation of electrodes providing improved slurry design rules for future high performance electrode manufacturing
Sublinear time approximation of the cost of a metric k-nearest neighbor graph
No full textLet (X,d) be an n-point metric space. We assume that (X,d) is given in the distance oracle model, that is, X-{1,...,n} and for every pair of points x,y from X we can query their distance d(x,y) in constant time. A k-nearest neighbor (k-NN) graph for (X,d) is a directed graph G-(V,E) that has an eduge to each of v's ka nearest neighbors. We use cost(G) to denote the sum of edge weights of G. In this paper, we study the problem of approximating cost(G) in sublinear time when we are given oracle access to the metric space (X,d) that defines G. Our goal is to develop an algorithm that solves this problem faster than the time required to compute G. We first present an algorithm that in Õε(n^2/k) time with probability at least 2/3 approximates cost(G) to within a factor of 1+ε. Next, we present a more elaborate sublinear algorithm that in time Õε(min{nk^3/2, n^2/k}) computes an estimate cost of cost(G) that satisfies with probability at least 2/3 |cost(G) - cost|≤ε ⋅ (cost(G)+mst(X)), where mst(X) denotes the cost of the minimum spanning tree of (X,d). Further, we complement these results with near matching lower bounds. We show that any algorithm that for a given metric space (X,d) of size n, with probability at least 2/3, estimates cost(G) to within a 1+ε factor requires Ω(n^2/k) time. Similarly, any algorithm taht with probability at least 2/3 estimates cost(G) to wtihin an additive error term ε ⋅ (mst(X) + cost(X)) requires Ωε(min{nk^3/2, n^2/k}) time