We view innovation investments as real options and explore the implications of risk (volatility) as well as a newly defined outcome independent measure of ambiguity (Knightian uncertainty) for innovation decisions. The empirical analysis uses stock returns to compute an implementable measure of ambiguity. We also control for risk and other determinants of innovation. We find a consistently significant negative effect of ambiguity on R&D, patents, and citations, as predicted. The effect of risk on R&D is positive and significant, but the corresponding effect on patents and citations is negative and significant. Ambiguity matters more for high-tech firms, consistent with intuition.

For any positive integers $k_1,k_2$ and any set $A\subseteq \mathbb {N}$, let $R_{k_1,k_2}(A,n)$ be the number of solutions of the equation $n=k_1a_1+k_2a_2$ with $a_1,a_2\in A$. Let g be a fixed integer. We prove that if $k_1$ and $k_2$ are two integers with $2\le k_1<k_2$ and $(k_1,k_2)=1$, then there does not exist any set $A\subseteq \mathbb {N}$ such that $R_{k_1,k_2}(A,n)-R_{k_1,k_2}(\mathbb {N}\setminus A,n)=g$ for all sufficiently large integers n, and if $1=k_1<k_2$, then there exists a set A such that $R_{k_1,k_2}(A,n)-R_{k_1,k_2}(\mathbb {N}\setminus A,n)=1$ for all positive integers n.

This review will provide an overview of the immune system and then describe the effects of frailty, obesity, specific micronutrients and the gut microbiota on immunity and susceptibility to infection including data from the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic where relevant. A key role for the immune system is providing host defence against pathogens. Impaired immunity predisposes to infections and to more severe infections and weakens the response to vaccination. A range of nutrients, including many micronutrients, play important roles in supporting the immune system to function. The immune system can decline in later life and this is exaggerated by frailty. The immune system is also weakened with obesity, generalised undernutrition and micronutrient deficiencies, which all result in increased susceptibility to infection. Findings obtained during the SARS-CoV-2 pandemic support what was already known about the effects of ageing, frailty and obesity on immunity and susceptibility to infection. Observational studies conducted during the pandemic also support previous findings that multiple micronutrients including vitamins C, D and E, zinc and selenium and long-chain n-3 fatty acids are important for immune health, but whether these nutrients can be used to treat those already with coronavirus disease discovered in 2019 (COVID-19), particularly if already hospitalised, is uncertain from current inconsistent or scant evidence. There is gut dysbiosis in patients with COVID-19 and studies with probiotics report clinical improvements in such patients. There is an inverse association between adherence to a healthy diet and risk of SARS-CoV-2 infection and hospitalisation with COVID-19 which is consistent with the effects of individual nutrients and other dietary components. Addressing frailty, obesity and micronutrient insufficiency will be important to reduce the burden of future pandemics and nutritional considerations need to be a central part of the approach to preventing infections, optimising vaccine responses and promoting recovery from infection.

An individual’s birthweight, a marker of in utero exposures, was recently associated with certain psychiatric conditions. However, studies investigating the relationship between an individual’s preterm birth status and/or birthweight and risk for depression during adulthood are sparse; we used data from the Women’s Health Initiative (WHI) to investigate these potential associations. At study entry, 86,925 postmenopausal women reported their birthweight by category (<6 lbs., 6–7 lbs. 15 oz., 8–9 lbs. 15 oz., or ≥10 lbs.) and their preterm birth status (full-term or ≥4 weeks premature). Women also completed the Burnham screen for depression and were asked to self-report if: (a) they had ever been diagnosed with depression, or (b) if they were taking antidepressant medications. Linear and logistic regression models were used to estimate unadjusted and adjusted effect estimates. Compared to those born weighing between 6 and 7 lbs. 15 oz., individuals born weighing <6 lbs. (βadj = 0.007, P < 0.0001) and ≥10 lbs. (βadj = 0.006, P = 0.02) had significantly higher Burnam scores. Individuals born weighing <6 lbs. were also more likely to have depression (adjOR 1.21, 95% CI 1.11–1.31). Individuals born preterm were also more likely to have depression (adjOR 1.18, 95% CI 1.02–1.35); while attenuated, this association remained in analyses limited to only those reportedly born weighing <6 lbs. Our research supports the role of early life exposures on health risks across the life course. Individuals born at low or high birthweights and those born preterm may benefit from early evaluation and long-term follow-up for the prevention and treatment of mental health outcomes.

The Paris-trained, Japanese composer Michiko Toyama (1913–2006) was appointed as the earliest foreign-born visiting composer at the Columbia-Princeton Electronic Music Center (CPEMC), the first institutionally supported studio of its kind in the United States. Yet she remains virtually unknown to scholarship, despite a growing literature on women pioneers in electronic music. Drawing on interviews, archival research, and the interpretive study of music, this article studies the conditions under which Toyama has found little remembrance to date; and it conceptualizes Toyama's own ideas of modernity formulated over the massive cultural and geographical dislocations of her lifetime. Within an intensely lyrical compositional practice, Toyama thematized hallmarks of traditional modernism studies: self-reflexivity, estrangement, exile, and exoticism. Racist criticism during her lifetime dismissed her music as a belated mimicry of Western models. Yet the modernist qualities and themes of her work emerge as a consequence of her life lived in intercultural contact zones of uprooting – the very conditions that make ideas of the ‘modern’ possible.

A range of health effects are associated with debt burdens from ubiquitous access to expensive credit. These health effects are concerning, especially for women who owe multiple types of higher-cost debt simultaneously and experience significantly higher stress associated with their debt burdens when compared to men. While debt burdens have been shown to contribute to poor mental and physical health, the potential gendered and racialized effects are poorly understood. We conducted interviews between January and April 2021 with twenty-nine racially marginalized women who reported owing debt, and used theoretical concepts of predatory inclusion and intersectionality to understand their experiences. Women held many types of debt, most commonly from student loans, medical bills, and credit cards. Women described debt as a violent, abusive, and inescapable relationship that exacted consequential tolls on their health. Despite these, women found ways to resist the violence of debt, to care for themselves and others, and to experience joy in their daily lives.

Let $\pi$ be a discrete group, and let $G$ be a compact-connected Lie group. Then, there is a map $\Theta \colon \mathrm {Hom}(\pi,G)_0\to \mathrm {map}_*(B\pi,BG)_0$ between the null components of the spaces of homomorphisms and based maps, which sends a homomorphism to the induced map between classifying spaces. Atiyah and Bott studied this map for $\pi$ a surface group, and showed that it is surjective in rational cohomology. In this paper, we prove that the map $\Theta$ is surjective in rational cohomology for $\pi =\mathbb {Z}^m$ and the classical group $G$ except for $SO(2n)$, and that it is not surjective for $\pi =\mathbb {Z}^m$ with $m\ge 3$ and $G=SO(2n)$ with $n\ge 4$. As an application, we consider the surjectivity of the map $\Theta$ in rational cohomology for $\pi$ a finitely generated nilpotent group. We also consider the dimension of the cokernel of the map $\Theta$ in rational homotopy groups for $\pi =\mathbb {Z}^m$ and the classical groups $G$ except for $SO(2n)$.

In this brief communication, we discuss the current landscape and unmet needs of pediatric to adult transition care in neurology. Optimizing transition care is a priority for patients, families, and providers with growing discussion in neurology. We also introduce the activities of the University of Toronto Pediatric-Adult Transition Working Group – a collaborative interdivisional and inter-subspeciality group of faculty, advanced-practice providers, trainees, and patient-family advisors pursuing collaboration with patients, families, and universities from across Canada. We envision that these efforts will result in a national neurology transition strategy that will inform designation of health authority attention and funding.

Ilex paraguariensis A. St.-Hil. (yerba mate) (Aquifoliaceae Bercht. & J. Presl) is a plant species with great economic and cultural importance because its leaves are processed and ground to make infusions like mate or tereré. The species is distributed in a continuous area that includes Southern Brazil and part of Paraguay and Argentina. Uruguay represents the Southern distribution limit of the species, where small populations can be found as part of ravine forests. Although there are previous reports of molecular markers for this and other species in the genus, the available markers were not informative enough to represent the intra- and interpopulation genetic diversity in marginal Uruguayan populations. In this study, we developed highly informative polymorphic microsatellite markers to be used in genetic studies in I. paraguariensis. Markers were identified in contigs from the genome sequence of two individuals and then tested for amplification and polymorphism content in a diverse panel. Markers which passed these filters were tested on populations from Uruguay. They detected higher diversity within populations (in terms of number of alleles and heterozygosity) than previously reported, and levels of heterozygosity similar to those reported for two Brazilian populations. This subset of seven markers were successfully multiplexed, substantially reducing the costs of the analysis. Combined with previously reported nuclear and plastid markers, they can be used to evaluate the genetic diversity of rear-edge populations, identify genotypes for paternity studies and provide relevant information for the conservation and management of germplasm.

Why does the ability of political leaders to control the bureaucracy vary? With strong meritocratic recruitment and tenure protections, Brazil appears an ideal case for successful bureaucratic resistance against political control. However, our analysis reveals how Bolsonaro overcame initial resistance by recalibrating strategies, ultimately dominating many key sectors of the bureaucracy. Drawing on over 100 interviews with public officials, we find that strategies of political control and bureaucratic resistance unfold in a dynamic, yet often predictable, pattern based on leaders' previous experiences and their ability to learn, adjust, and tighten their grip on the instruments of the state. The Bolsonaro administration transformed the regulatory framework and targeted individual state employees, reducing arenas of contestation and inducing public sector workers to remain silent, implementing the president’s policy preferences. We examine these control strategies in environmental agencies, their replication, and potential long-term consequences.

As a multi-faceted socio-political movement in twentieth-century China, the Cultural Revolution (1966–1976) witnessed conflict and social upheaval. This paper investigates its economic legacies, exploiting geographic variation in revolutionary intensity, measured by the number of resulting deaths. Using a newly assembled county-level panel dataset over five decades, we find worse-affected areas performed slightly better at baseline, but were slower to industrialize. This effect was large in the early 1980s before diminishing to become insignificant by 2000. Using individual-level census data, we find more-exposed cohorts are less likely to obtain higher education degrees and to work in professional and entrepreneurial occupations.