Neural Network Potentials: A Concise Overview of Methods

In the past two decades, machine learning potentials (MLPs) have reached a level of maturity that now enables applications to large-scale atomistic simulations of a wide range of systems in chemistry, physics, and materials science. Different machine learning algorithms have been used with great success in the construction of these MLPs. In this review, we discuss an important group of MLPs relying on artificial neural networks to establish a mapping from the atomic structure to the potential energy. In spite of this common feature, there are important conceptual differences among MLPs, which concern the dimensionality of the systems, the inclusion of long-range electrostatic interactions, global phenomena like nonlocal charge transfer, and the type of descriptor used to represent the atomic structure, which can be either predefined or learnable. A concise overview is given along with a discussion of the open challenges in the field. Expected final online publication date for the Annual Review of Physical Chemistry, Volume 73 is April 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Changes in Antioxidant Defence System in Durum Wheat under Hyperosmotic Stress: A Concise Overview

Durum wheat is one of the most commonly cultivated species in the world and represents a key commodity for many areas worldwide, as its grain is used for production of many foods, such as pasta, bread, couscous, and bourghul. Durum wheat grain has a relevant role in the human diet, providing carbohydrates, proteins, lipids, fibres, vitamins, and minerals, as well as highly valued bioactive compounds contributing to a healthy diet. Durum wheat is largely cultivated in the Mediterranean basin, where it is mainly grown under rain-fed conditions, thus currently undergoing drought stress, as well as soil salinity, which can hamper yield potential and influence the qualitative characteristics of grain. When plants suffer drought and/or salinity stress, a condition known as hyperosmotic stress is established at cellular level. This leads to the accumulation of ROS thus generating in turn an oxidative stress condition, which can ultimately result in the impairment of cellular integrity and functionality. To counteract oxidative damage due to excessive ROS production under stress, plants have evolved a complex array of both enzymatic and non-enzymatic antioxidant mechanisms, working jointly and synergically for maintenance of ROS homeostasis. Enhancement of antioxidant defence system has been demonstrated as an adaptive mechanism associated to an increased tolerance to hyperosmotic stress. In the light of these considerations, this review provides a concise overview on recent advancements regarding the role of the ascorbate-glutathione cycle and the main antioxidant enzymes (superoxide dismutase, catalase, and peroxidases) in durum wheat response to drought and salt stresses that are expected to become more and more frequent due to the ongoing climate changes.

United Nations Psychology Day 2021 Focused on Post-Pandemic Rebuilding

In the wake of the unprecedented global COVID-19 lockdowns in 2020, the Psychology Coalition at the United Nations (PCUN) managed to continue to pursue its mission, to apply psychological science to global issues at the UN. This two-part report offers a concise overview of (a) recent PCUN activities in 2020-2021, and (b) the PCUNs 14th annual Psychology Day at the UN on April 15, 2021, which focused on Psychological Contributions to Building Back Better in a Post-Pandemic World.

An Orthodox perspective on hamartology and ecology: Assessing John Chryssavgis’ contribution to current discourse

This article is a sequel to my earlier paper entitled ‘Hamartology and Ecology: An assessment of Aruna Gnanadason’s contribution to the contemporary debate’. Christian ecotheology presents a Christian critique of ecological destruction while also offering an ecological critique of Christianity. It entails a reinterpretation of all the classic Christian symbols, in this case the doctrine of sin, specifically the nature of sin, explored in the light of ecological discourse. Considering the contemporary ecological crisis, this article highlights Orthodox theologian John Chryssavgis’ contribution to the current debate. Following a concise overview on Christian discourse on ecology, as well as the Christian understanding of the nature of sin and the ways in which it is re-described in contemporary ecotheological terms, this article explores John Chryssavgis’ position on ecotheological discourse through a discussion of anthropocentrism, domination in the name of differences of species, consumerist greed, alienation of humans from the earth community as well as denial and disdain. The Orthodox tradition is an important factor in the formulation of his ecotheology. The method employed here encompasses ecclesial scrutiny, namely Chryssavgis’ assessment of the Christian tradition’s role in contributing to the contemporary crisis, followed by theological reflection on his interpretations of ecological sin and finally, alternative courses of action to appropriately address the issues in question. In closing, the article offers an assessment of Chryssavgis’ overall contribution to current ecotheological discourse.

The [4.3.0] piperidine alkaloids: architectures, biology, biosyntheses and the complete details of the asymmetric syntheses of streptazone A and abikoviromycin

Piperidine alkaloids continue to challenge the synthetic community by featuring densely functionalized scaffolds which often requires careful chemical orchestration. Streptazone A and abikoviromycin are small and highly functionalized piperidine alkaloids both accommodating Michael acceptors and a labile epoxide. These moieties are loaded into a [4.3.0] bicyclic core also present in other structurally related natural products including the well-known piperidine alkaloid streptazolin. Herein, we cover ring-closing strategies employed in prior streptazolin syntheses, provide a concise overview of structures, biological properties and biosyntheses of selected [4.3.0] piperidine alkaloids, and finally we disclose a complete coverage of our recent asymmetric syntheses of streptazone A and abikoviromycin.

On the elasticity of centres and the possibility of multiple roofs: revisiting some of Ulrich Ammon’s views on language variation and pluricentricity

Against the background of a concise overview of Ulrich Ammon’s oeuvre this article first of all provides a constructive-critical account of some of the key concepts and questions that guided his macrosociolinguistic work on pluricentric languages and variation in German. In what follows, an attempt is made to further develop some of Ammon’s thoughts through emphasising the elasticity of the concept of pluricentricity and arguing for a creative use of the concept of “roofing” when describing the intricate interplay of standard and nonstandard varieties especially in language contact zones.