The air pollution tradeoff in India: Saving more lives versus reducing the inequality of exposure

Chronic exposure to ambient fine particulate matter (PM2.5) represents one of the largest global public health risks, leading to millions of premature deaths annually. For a country facing high and spatially variable exposures, prioritizing where to reduce PM2.5 concentrations leads to an inherent tradeoff between saving the most lives and reducing inequality of exposure. This tradeoff results from the shape of the concentration-response function between exposure to PM2.5 and mortality, which indicates that the additional lives saved per unit reduction in PM2.5 declines as concentrations increase. We estimate this concentration-response function for urban areas of India, finding that a 10 unit reduction in PM2.5 in already-clean locations will reduce the mortality rate substantially (4.2% for a reduction from 30 to 20 µgm-3), while a 10 unit reduction in the dirtiest locations will reduce mortality only modestly (1.2% for a reduction from 90 to 80 µgm-3). We explore the implications of this PM2.5/mortality relationship by considering a thought experiment. If India had a fixed amount of resources to devote to PM2.5 concentration reductions across urban areas, what is the lives saved/inequality of exposure tradeoff from three different methods of employing those resources? Across our three scenarios—1) which reduces exposures for the dirtiest districts, 2) which reduces exposures everywhere equally, and 3) which reduces exposures to save the most lives—scenario 1 saves 18,000 lives per year while reducing the inequality of exposure by 65%, while scenario 3 saves 126,000 lives per year, but increases inequality by 19%.

Hidden Dissipation and Irreversibility in Maxwell’s Demon

Maxwell’s demon is an entity in a 150-year-old thought experiment that paradoxically appears to violate the second law of thermodynamics by reducing entropy without doing work. It has increasingly practical implications as advances in nanomachinery produce devices that push the thermodynamic limits imposed by the second law. A well-known explanation claiming that information erasure restores second law compliance fails to resolve the paradox because it assumes the second law a priori, and does not predict irreversibility. Instead, a purely mechanical resolution that does not require information theory is presented. The transport fluxes of mass, momentum, and energy involved in the demon’s operation are analyzed and show that they imply “hidden” external work and dissipation. Computing the dissipation leads to a new lower bound on entropy production by the demon. It is strictly positive in all nontrivial cases, providing a more stringent limit than the second law and implying intrinsic thermodynamic irreversibility. The thermodynamic irreversibility is linked with mechanical irreversibility resulting from the spatial asymmetry of the demon’s speed selection criteria, indicating one mechanism by which macroscopic irreversibility may emerge from microscopic dynamics.

Frog and Toad at the Academy: Gareth B. Matthews on how children’s literature goes philosophical

Gareth B. Matthews (1929–2011) inaugurated the study of philosophy in children’s literature by simultaneously arguing (1) that philosophy is essentially an encounter with certain kinds of perplexities, (2) that genuine philosophical perplexities are readily found in many children’s stories, and (3) that many children are capable of appreciating and enjoying them. He wrote 58 reviews of philosophical children’s stories and co-authored a series of teacher guides for using such stories. Following Matthews’ example, others have produced resources recommending children’s stories as stimuli for intergenerational philosophical dialog. In our research, we study and systematize the different ways that Matthews understood children’s stories to go philosophical. Here, we introduce five of those ways: philosophical story irony, philosophical story fancy, thought experiment, philosophical fable, and philosophical story realism. For each of these ways, we define a set of literary elements and describe the kind of philosophical perplexity they invite, illustrating with examples from children’s literature reviewed and discussed by Matthews. We intend our article to shed new light on Matthews’ scholarship, to guide (ourselves and others) in locating some of the elements in children’s stories that occasion different types of philosophical perplexity, and to spark new conversations among philosophers and educators about this promising field.

CLEANING THE BRAIN THROUGH TURBULENT GLYMPHATIC FLOW: THE WASHING MACHINE HYPOTHESIS

LYMPHSPIRATION: In a thought experiment, a "washing machine" model is proposed based on turbulent flow from complex multi-dimensional forces to characterize fluid dynamics in the brain. The glymphatic system's hypothetical role in this system is illustrated in a series of diagrams. Implications of this model are discussed in terms of normal physiology and a variety of pathologic conditions such as brain atrophy and Alzheimer disease.

MEDIATION ANALYSIS TO INFORM POLICY ON CORONARY REVASCULARIZATION BY EXPECTED TIME TO TREATMENT: ANALYTICAL FRAMEWORK

Objectives Clinical guidelines favor coronary artery bypass grafting (CABG) over percutaneous coronary intervention (PCI) for patients with stable complex coronary disease. Yet the benefit of CABG as established in trials may not be generalizable to populations in which treatment method determines time to treatment, typically being longer for CABG. For cases in which the cardiac anatomy is suitable for either treatment, it is unclear whether it is appropriate to recommend CABG, which is likely to be delayed, if PCI can be performed sooner. This paper outlines an analytical framework for a policy analysis of the timing of coronary revascularization. Methods We constructed a thought experiment to examine whether time to treatment will influence the advantage of CABG. We substantiated the use of mediation analysis to estimate the extent to which differences in outcomes between CABG and PCI would change if times to CABG were the same as times to PCI. Results We designed a study that uses data from a population-based patient registry to obtain effect measures of mediation analysis: the total effect, the natural indirect effect, and the natural direct effect. The partitioning of the total effect will allow us to estimate the proportional reduction in the risk of an outcome if the time to CABG was similar to that of PCI. Interpretation Treatment recommendation, resource allocation and scheduling benchmarks will be guided by understanding the extent to which the time to treatment mediates the relation between revascularization method and outcome.

Johannes Kepler's 'Somnium' and the Witches' Night Flight

This article explores the uses of the witches' night-flight in Johannes Kelper’s Somnium (1634). It situates Kepler's engagement with the motif in the broader context of debates on the reality of the night-flight among early modern witch theorists, including Kepler's contemporary and friend, Georg Gödelmann. It proposes that Kepler understood the night-flight as a phenomenon with a disputed reality status and, as such, an appropriate imaginative space through which to pursue the thought experiment of lunar travel. Consequently, it suggests that we ought not to dismiss Kepler's engagements with the figure of the witch as a vestigial medieval superstition (itself a problematic contention), but rather an interest characteristic of his age, and that we might find in the speculations of witch-theory the very beginnings of science fiction.

Can Sport Exist Without Aggression? On a Certain Thought Experiment by Stanisław Lem

The main objective of the paper is to present and analyse a thought experiment concerning the existence and specifi city of sport in a society completely devoid of aggression. The experiment comes from the novel Return from the Stars by Stanisław Lem, Polish writer and thinker. The article provides an explanation why sports, and boxing in particular, were included in Lem’s refl ections on the problem of evil and attempts to “improve the world”. Lem’s vision of sport in a society subjected to betrization – a procedure that eliminates aggression – is presented and commented on from the perspective of the contemporary philosophy of sport. The presented analysis of Lem’s considerations focuses on their relationships with currently debated issues. An illustration of this thread of considerations is tchoukball – a sport designed to minimise players’s aggression.

Uniform Scaling: Relativistic Energy-Momentum Relationships

A number of the most often cited results of relativity theory deal with the relationships between energy, momentum and inertial mass. The history of how Einstein and Planck came to these conclusions is reviewed. It is pointed out that considerations of how the speed of light is affected by the motion of the Earth played a determining role in these developments. After the Michelson-Morley null-interference result became available, Voigt introduced a new space-time transformation by amending the classical Galilean transformation so that the speed of light in free space has the same value of c regardless of the state of motion of both the light source and the observer. This led to the Lorentz transformation which has been the cornerstone of relativity theory for the past century. A thought experiment is presented which proves, however, that there are many situations for which the measured speed of light is NOT equal to c. Furthermore, it is pointed out that the rate of an inertial clock cannot change spontaneously, which result is perfectly compatible with Newton’s First Law of Kinetics (Law of Inertia). This result contradicts the space-time mixing characteristic of the Lorentz transformation and leads to the conclusion that events which are spontaneous for one inertial frame will also be so for every other one. The uniform scaling procedure is a generalization of this result for all other physical properties than elapsed times. Its application shows that the commonly accepted relationships between energy and momentum are only special cases in which it is assumed that the observer is stationary in the rest frame in which force has been applied to cause the object’s acceleration

‘Pathetic earthlings! Who can save you now?’ Science fiction, planetary crisis and the globalisation of Chinese culture

Chinese policy has turned to the globalisation of communication and stories. Beyond the diplomatic ‘voice’, one of the ways that Chinese culture is reaching out to the rest of the world is through science fiction. Sci-fi can be construed as a specialist thinking-circuit for cultures to build and explore experimental models of collective action at global and planetary scale. What do its stories tell us about the globalisation of Chinese culture? When the need to ‘save the world’ has crossed over from sci-fi to science, from entertainment to activism, and from a thought experiment to imminent danger, humans as a whole face challenges of their own making: climate change, environmental pollution, pandemics, extinctions, exclusions and nuclear annihilation. Can sci-fi inspire collective action at species scale? What role will globalising China play?