The Business Cycle, Macroeconomic Shocks and the Cross Section: Evidence from UK Quoted Companies

Co-movements and correlations in the major macroeconomic aggregates has been the focus of much of the recent literature in business cycle research. In this paper we provide another dimension to business cycle analysis. We examine the evolution of the cross sectional distribution of the growth of UK quoted companies from 1968 to 1997 and find correlations between aggregate business cycle fluctuations and the higher moments of the cross sectional distribution. To explain this we analyse the sensitivity of firms to aggregate shocks, conditioning growth on firm size, age and industry. We find that the contemporaneous effects of aggregate shocks, both positive and negative, are significantly more pronounced for firms in the middle range of growth. This explains the cycle-related patterns in the moments of the growth rate cross section. These findings are of importance in understanding firm level as well as business cycle dynamics.

Managing students' option choices with technology

This poster outlines the system which the Business School Undergraduate Programme has developed to manage the choice of options by students studying on its programmes. This involves the production of a networked computer package which presents students with the options available to them and leads them through the process of choosing their options on-line. The reasons for developing this system are outlined and the advantages which it has brought to the administration of large numbers of students are discussed

Operating Leverage over the Business Cycle

Operating leverage describes the extent to which a firm's operating costs are fixed in the short run. The effect of operating leverage is to amplify the impact on profit of a change in revenues; an effect which is further amplified by financial leverage and by asymmetry in the tax system. In this paper we provide empirical estimates of operating leverage at the firm level, using a long panel of data on UK quoted firms. We report sectoral differences in operating leverage around the business cycle, and show that these can be partly explained in terms of costly labour adjustment and asymmetric price adjustment

Aggregate and Firm level volatility: the role of acquisitions and disposals.

The purpose of this paper is to revisit an intriguing finding. Although over the last few decades leading up to the financial crisis there was a marked reduction in the volatility of aggregate output and inflation, there appears to have been a corresponding increase in the sales volatility of individual firms. Here we argue that a significant reason for this apparent increase in firm level volatility was an increase in churning of firm activity through the acquisition and disposal of businesses. This created an increase in observed negative covariances between firms, so even if the volatility of underlying organic growth has also fallen, observed volatility has rise

The Baum-Connes Conjecture via Localisation of Categories

We redefine the Baum-Connes assembly map using simplicial approximation in the equivariant Kasparov category. This new interpretation is ideal for studying functorial properties and gives analogues of the assembly maps for all equivariant homology theories, not just for the K-theory of the crossed product. We extend many of the known techniques for proving the Baum-Connes conjecture to this more general setting

Spectral triples and manifolds with boundary

We investigate manifolds with boundary in noncommutative geometry. Spectral triples associated to a symmetric differential operator and a local boundary condition are constructed. For a classical Dirac operator with a chiral boundary condition, we show that there is no tadpole.Comment: 18 pages To appear in J. Funct. Ana

Rapid Systematic Review: The Impact of Social Isolation and Loneliness on the Mental Health of Children and Adolescents in the Context of COVID-19

OBJECTIVE: Disease containment of COVID-19 has necessitated widespread social isolation. We aimed to establish what is known about how loneliness and disease containment measures impact on the mental health in children and adolescents. METHOD: For this rapid review, we searched MEDLINE, PSYCHINFO, and Web of Science for articles published between 01/01/1946 and 03/29/2020. 20% of articles were double screened using pre-defined criteria and 20% of data was double extracted for quality assurance. RESULTS: 83 articles (80 studies) met inclusion criteria. Of these, 63 studies reported on the impact of social isolation and loneliness on the mental health of previously healthy children and adolescents (n=51,576; mean age 15.3) 61 studies were observational; 18 were longitudinal and 43 cross sectional studies assessing self-reported loneliness in healthy children and adolescents. One of these studies was a retrospective investigation after a pandemic. Two studies evaluated interventions. Studies had a high risk of bias although longitudinal studies were of better methodological quality. Social isolation and loneliness increased the risk of depression, and possibly anxiety at the time loneliness was measured and between 0.25 to 9 years later. Duration of loneliness was more strongly correlated with mental health symptoms than intensity of loneliness. CONCLUSION: Children and adolescents are probably more likely to experience high rates of depression and probably anxiety during and after enforced isolation ends. This may increase as enforced isolation continues. Clinical services should offer preventative support and early intervention where possible and be prepared for an increase in mental health problems

Representation theory of some infinite-dimensional algebras arising in continuously controlled algebra and topology

In this paper we determine the representation type of some algebras of infinite matrices continuously controlled at infinity by a compact metrizable space. We explicitly classify their finitely presented modules in the finite and tame cases. The algebra of row-column-finite (or locally finite) matrices over an arbitrary field is one of the algebras considered in this paper, its representation type is shown to be finite.Comment: 33 page

Loneliness and mental health in children and adolescents with pre-existing mental health problems: A rapid systematic review

Objectives: Periods of social isolation are associated with loneliness in children and young people, and loneliness is associated with poor mental and physical health. Children and young people with pre-existing mental health difficulties may be prone to loneliness. Containment of COVID-19 has necessitated widespread social isolation, with unprecedented school closures and restrictions imposed on social interactions. This rapid review aimed to establish what is known about the relationship between loneliness and mental health problems in children and young people with pre-existing mental health problems. Methods: We sought to identify all primary research that examined the cross-sectional and longitudinal associations between loneliness/perceived social isolation and mental health in children and young people with pre-existing mental health problems. We also aimed to identify effective interventions that reduce the adverse impact of loneliness. A rapid systematic search was conducted using MEDLINE, PsycINFO, and Web of Science. Results: Of 4,531 papers screened, 15 included children and young people with pre-existing mental health conditions. These 15 studies included 1,536 children and young people aged between 6 and 23 years with social phobia, anxiety and/or depression, and neurodevelopmental disorders. Loneliness was associated with anxiety and depression both cross-sectionally and prospectively in children and young people with mental health problems and neurodevelopmental conditions. We found preliminary evidence that psychological treatments can help to reduce feelings of loneliness in this population. Conclusions: Loneliness is associated with depression and anxiety in children and young people with pre-existing mental health conditions, and this relationship may be bidirectional. Existing interventions to address loneliness and/or mental health difficulties in other contexts may be applied to this population, although they may need adaptation and testing in younger children and adolescents. Practitioner points: Loneliness is common in children and young people, and during periods of enforced social isolation such as during COVID-19, children and young people report high levels of loneliness (or increased rates of loneliness). The review showed that loneliness is associated, both cross-sectionally and prospectively, in children and young people with mental health problems and also in children and young people with neurodevelopmental conditions, such as autism spectrum disorder. Thus, loneliness is a possible risk factor of which mental health providers should be aware. Maintaining social contact both by direct and by indirect means, especially through the Internet, could be important in mitigating loneliness. Interventions to address loneliness should be further developed and tested to help children and young people with pre-existing mental health problems who are lonely by preventing exacerbation of their mental health difficulties, in particular anxiety and depression