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Hall's marriage theorem
No full textIn 1935, Philip Hall published what is often referred to as ‘Hall's marriage theorem’ in a short paper (P. Hall, J. Lond. Math. Soc. (1) 10 (1935), no. 1, 26–30.) This paper has been very influential. I state the theorem and outline Hall's proof, together with some equivalent (or stronger) earlier results, and proceed to discuss some the many directions in combinatorics and beyond which this theorem has influenced
How is cold, star-forming gas in galaxies affected by magnetic fields?
No full textNumerical simulations provide a unique opportunity to improve our understanding of the role of magnetic fields in the interstellar medium of galaxies and in star formation. However, many existing galaxy-scale numerical simulations impose a Kennicutt–Schmidt (KS) star formation law by construction. In this paper, we present two AREPO simulations of an isolated star-forming galaxy with and without magnetic fields, using sink particles to model star formation without imposing a KS relation. We examine global differences between the models and investigate the impacts on star formation. We include a time-dependent, non-equilibrium chemical network coupled to a thermal evolution scheme and supernova feedback. Our magnetic field amplifies via dynamo action from a small initial seed field. We find a more compact magnetohydrodynamic (MHD) disc (radius ∼5.1 kpc, compared to ∼7.4 kpc), with a diffuse atomic envelope above and below the plane that is not seen in the hydrodynamic (HD) case. The HD disc displays a smoother, more even radial distribution of gas and star formation, and more bubbly substructure. Our MHD simulation has a higher proportion of dense, gravitationally unbound gas than the HD case, but a lower star formation rate, an average between 125 and 150 Myr of ∼ 4.8 M☉ yr−1 compared to ∼ 8.4 M☉ yr−1. We see a clear shift in the KS relation to higher gas surface densities in the MHD case, more consistent with observations. The additional magnetic support against gravitational collapse seems to raise the threshold gas surface density required for star formation
Psychiatric admission in female survivors of childhood and young adult cancer:a whole population retrospective study
No full textBackground The last 40 years have seen a substantial improvement in overall survival from cancer in children and young people. There is limited information on psychiatric wellbeing in female survivors of cancer at a young age.Objective In this 40-year population-based linkage study, we set out to determine the incidence of first psychiatric admission compared with a non-exposed age-matched control.Methods Scottish cancer registry records from 1981 to 2012 were linked to psychiatric admissions, maternity and death records from January 1981 to September 2018 using the unique personal Community Health Index number allocated to each person in Scotland. For each exposed subject, three age and deprivation matched controls from the population were selected. The primary exposed group was all females with a cancer diagnosis at age <25 years and no previous pregnancy and no psychiatric admission before cancer diagnosis. The main outcome measure is admission to a psychiatric hospital with a mental health diagnosis.Findings Female cancer survivors had a significantly lower cumulative incidence of first psychiatric admissions than matched controls over the 38 years of follow-up for the cohort (p<0.05). The relative risk of a first psychiatric admission at 25 years from cancer diagnosis was 0.72 (0.56–0.89).Conclusion Overall, we have shown that young cancer survivors are less likely than age-matched controls to have a psychiatric admission after cancer diagnosis. In particular, psychiatric admissions for mood disorders, neuroses, personality disorders and substance use are significantly less likely in the cancer survivors.Clinical implications The experience of cancer treatment and survival in young females may reduce the risk of psychiatric admission in later life
Novel optical measurement technique for antimicrobial photodynamic therapy using Scattered Light Integrating Collector (SLIC)
No full textAdvancing new treatment modalities for microbial infections is a priority, given the threat of antimicrobial resistance. Current work includes the development of new non-traditional treatments, including antimicrobial photodynamic therapy (aPDT). Improvements in the field include innovative technologies that allow screening and optimization of the treatment. In this work it is shown how the Scattered Light Integrating Collector, a novel technology that optically measures bacterial growth in real time, can be used for rapid screening of aPDT using Organic Light Emitting Diodes (OLEDs) as the light source. This technology allows rapid screening of different concentrations of the photosensitizer and real-time observation of the effect of aPDT on Staphylococcus aureus. Evaluation of aPDT efficacy using methylene blue and OLEDs as the light source showed significant inhibition of the growth of S. aureus (3.06, 3.80, 4.24, 4.98 and 4.84 log10 reduction for the concentrations of MB of 1, 2, 4, 8 and 16 µM, respectively). The application of SLIC as a novel technology for evaluation of aPDT is a promising advance that will allow rapid optimization of the treatment
Computer simulations of a dynamic sodium pump-mediated hyperpolarization and short-term motor memory in the spinal locomotor network of Xenopus frog tadpoles
No full textSimple four-neuron computational models comprising bilateral pairs of excitatory dIN and inhibitory cIN neurons were used to test several hypotheses concerning the role of electrogenic sodium pumps in shaping swimming CPG output in Xenopus tadpoles. The initial model had no sodium pumps and generated continuous swim-like rhythmic activity. In real tadpoles, activity-dependent “dynamic” sodium pumps are proposed to mediate the postswim ultraslow afterhyperpolarization (usAHP) apparent in most cINs that reduces subsequent swim episode durations, producing a form of short-term motor memory (STMM). Dynamic pumps were therefore incorporated into model cINs, which then generated a usAHP causing swimming episodes to self-terminate, and when interswim intervals were varied, the model also replicated STMM. In real tadpoles, no usAHP is normally apparent in dINs, but one can be revealed by pharmacologically blocking the hyperpolarization-activated current, Ih, which is exclusively expressed in dINs. Dynamic pumps and HCN channels mediating Ih were therefore added to the model dINs. If HCN conductance was locked at its resting level, the dINs now showed a substantial pump-generated usAHP, but this was almost completely cancelled when HCN conductance was allowed to respond normally. Complete cancellation could be achieved by including a speculative cAMP-mediated modulation of the HCN activation kinetics. The models thus confirm the plausibility of published hypotheses regarding the generation of the usAHP in cINs, its apparent absence in dINs due to masking by Ih, and its role in mediating STMM. They also suggest the involvement of the usAHP in swim termination and possible regulation by cyclic nucleotides.NEW & NOTEWORTHY The tadpole locomotor network, an important model system in motor control, has been extensively modeled. Dynamic sodium pumps can generate a slow afterhyperpolarization (usAHP) that contributes to swimming. Here, we present novel computer models that incorporate these pumps and replicate both the usAHP and spinal motor memory. We also show that the usAHP can be masked by HCN channels, validating the conclusions of physiological experiments and suggesting new mechanisms of network function
Heritage buildings and objects’ digitisation and visualisation within the cloud (HERITALISE)
No full textHERITALISE mission is to research and develop advanced digitisation techniquesand solutions for documenting and representing diverse Cultural Heritageassets, giving a full comprehension of the diverse Cultural Heritage features, visible and non-visible. In addition, AI-powered tools including Machine Learning(ML) will be developed for improved and optimised data post-processing andintegration based on standard and expanded methodologies. All this will be connected through a knowledge graph environment that allows the individual aspects known about the CH object to be related and retrievable. As with Wikipedia, by following links it will be possible to learn more about a particular object, what research has been done, and what results have been derived from it. HERITALISE will provide the upcoming European Collaborative Cloud for CulturalHeritage with an interoperable web-based Ecosystem, advanced input data fromimproved digitalisation methodologies and preservation supporting tools, whichwill be achieved by meeting the projects general objectives
A woman's work:women soldiers, masculinities and binary panic in documentaries of the East German army
No full textThe East German National People's Army employed women in uniformed and civilian roles from its inception, yet in its self-presentation it strongly associated military service with masculinity and cis male bodies. Documentaries and newsreels from the military's own Army Film Studio, the DEFA documentary 'Gabi - Switchboard Position 12' (Uwe Belz, 1985) and the amateur film 'Trying and Prevailing' (Dietmar Schürtz, 1988) provide insights into women's negotiations of gender in the East German armed forces. Army Film Studio productions position women's military jobs as work like any other. To avoid disrupting the link between the military, masculinities and cis male bodies, though, these films overemphasise and stereotype women's femininity to minimise unsettling effects on military masculinities. These documentaries and newsreels constantly foreground and reinforce binary gender in ways that reveal it to be under pressure: I call these reactions to women's presence in uniform a form of 'binary panic'. Both 'Gabi' and 'Trying and Prevailing', by contrast, make space for women soldiers' own words and show how their presence in military training influenced their male comrades. The films show the work that goes into reinforcing binary gender and demonstrate how women embodied military masculinities and forced cis male comrades to reflect on what masculinity meant to them and to the army
The consultative meetings of heads of state of Central Asia:local norms, institutions, and the fundamentals of regional order
No full textSince 2018, the presidents of the five central Asian republics of Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan and Uzbekistan have gathered annually to participate in the Consultative Meetings of Heads of States of the region. This institutional development has been hailed as a new step towards integration and cooperation in central Asia. Yet several scholars and commentators describe this format as mostly a ‘talking shop’ that pays lip service to the idea of regional integration. To challenge this view, this article offers an emic and idiographic analysis of the Consultative Meetings from the analytical perspective of the English School, positing a twofold argument. First, it considers such meetings as an institution, i.e., a durable practice imbued with normativity and a sense of legitimacy and appropriateness that serves specific functions. Second, it maintains that the Consultative Meetings embody a regional cultural code in which consensus and informality are structuring elements of order, as opposed to representing weaknesses or failure thereof; and by which specific indigenous and political norms such as personal connections between presidents, seniority, respect and prestige affect the operations of fundamental regional primary institutions such as sovereignty, international law and diplomacy. The analysis relies on official materials and news items available online, unpublished documents provided to the author by central Asian diplomats, and interviews with foreign ministry staff members and officials from the region familiar with the workings of the meetings. The arguments offered in this article have implications for understanding processes of central Asian regionalism and non-western logics of order and legitimacy
When the dead speak in verse:collective writing and hauntological rhythms at Victor Hugo's Jersey séances
No full textWhile Victor Hugo’s infamous Jersey séances (1853-1855) have long inspired curiosity, bafflement or derision, the central role played by verse in these sessions has escaped critical attention. I argue that the tensions inherent in séance practice also underpin anxieties around poetic production in nineteenth-century France. The transcripts show verse composition to be a kind of séance, or intergenerational writing project, in which rhythm performs a hauntological function, producing a singular, original text while re-animating textual antecedents. By making visible what is usually an internal creative process, the séances reveal how poetry occupies a liminal space between individual and collective act
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