The response of reworked aerosols to climate through estimation of inter-particle forces

This paper describes the first use of inter-particle force measurement in reworked aerosols to better understand the mechanics of dust deflation and its consequent ecological ramifications. Dust is likely to carry hydrocarbons and micro-organisms including human pathogens and cultured microbes and thereby is a threat to plants, animals and human. Present-day global aerosol emissions are substantially greater than in 1850; however, the projected influx rates are highly disputable. This uncertainty, in part, has roots in the lack of understanding of deflation mechanisms. A growing body of literature shows that whether carbon emission continues to increase, plant transpiration drops and soil water retention enhances, allowing more greenery to grow and less dust to flux. On the other hand, a small but important body of geochemistry literature shows that increasing emission and global temperature leads to extreme climates, decalcification of surface soils containing soluble carbonate polymorphs and hence a greater chance of deflation. The consistency of loosely packed reworked silt provides background data against which the resistance of dust’s bonding components (carbonates and water) can be compared. The use of macro-scale phenomenological approaches to measure dust consistency is trivial. Instead, consistency can be measured in terms of inter-particle stress state. This paper describes a semi-empirical parametrisation of the inter-particle cohesion forces in terms of the balance of contact-level forces at the instant of particle motion. We put forward the hypothesis that the loss of Ca2+-based pedogenic salts is responsible for much of the dust influx and surficial drying pays a less significant role.

Flourishing as a dialectical balance: emerging insights from second-wave positive psychology

Positive psychology, an emergent branch of scholarship concerned with wellbeing and flourishing, initially defined itself by a focus on “positive” emotions and qualities. However, critics soon pointed out that this binary logic—classifying phenomena as either positive or negative, and valorising the former while disparaging the latter—could be problematic. For example, apparently positive qualities can be harmful to wellbeing in certain circumstances, while ostensibly dysphoric emotional states may on occasion promote flourishing. Responding to these criticisms, over recent years a more nuanced “second wave” of positive psychology has been developing, in which wellbeing is recognized as involving a dialectical balance of light and dark aspects of life. This article introduces this emergent second wave, arguing that it is characterized by four dialectical principles. First, the principle of appraisal states that it is difficult to categorically identify phenomena as either positive or negative, since such appraisals are fundamentally contextually dependent. Second, the principle of co-valence holds that many states and qualities at the heart of flourishing, such as love, are actually a complex blend of light and dark elements. Third, the principle of complementarity posits that not only are such phenomena co-valenced, but that their dichotomous elements are in fact co-creating, two intertwined sides of the same coin. Finally, the principle of evolution allows us to understand second-wave positive psychology as itself being an example of a dialectical process. This article is published as part of a collection entitled “On balance: lifestyle, mental health and wellbeing”.