Book review: Occupied America: British military rule and the experience of revolution by Donald F. Johnson

In Occupied America: British Military Rule and the Experience of Revolution, Donald F. Johnson offers a new account that explores the everyday experiences of American civilians living under British military occupation between 1775 and 1783. Drawing out the ambiguities, compromises and complexities of occupied life for ordinary people, this is a well-researched and insightful book that contributes to a fuller understanding of the American Revolution, writes Mark G. Spencer

Book review: Circulating enlightenment: the career and correspondence of Andrew Millar, 1725-68 by Adam Budd

In Circulating Enlightenment: The Career and Correspondence of Andrew Millar, 1725-68, Adam Budd brings together the letters of bookseller Andrew Millar, who played a central role in Britain’s eighteenth-century book world. Drawing out Millar’s dealings with David Hume and Adam Smith, key figures of the Scottish Enlightenment, this richly illustrated book explores Millar’s complex life in vivid detail, writes Mark Spencer. Circulating Enlightenment: The Career and Correspondence of Andrew Millar, 1725-68. Adam Budd. Oxford University Press. 2020

Book review: A philosopher’s economist: Hume and the rise of capitalism by Margaret Schabas and Carl Wennerlind

In A Philosopher’s Economist: Hume and the Rise of Capitalism, Margaret Schabas and Carl Wennerlind offer a new study that fills a gap in scholarship on David Hume, connecting his economic thought to his philosophy and showing the central place of Hume’s economics in his life and work. This is a well-researched and artfully written volume, finds Mark G. Spencer, that will leave readers with a much richer understanding of David Hume, his world and ours. A Philosopher’s Economist: Hume and the Rise of Capitalism. Margaret Schabas and Carl Wennerlind. University of Chicago Press. 2020

Book review: Uncivil mirth: ridicule in enlightenment Britain by Ross Carroll

In Uncivil Mirth: Ridicule in Enlightenment Britain, Ross Carroll offers a new study of ridicule’s function in public debate in Britain in the 1700s, exploring how laughter and humour were seen as ambiguous and fraught. Drawing on primary sources and modern historiography, this scholarly book will leave readers marvelling at the significance of debates on ridicule in eighteenth-century Britain, and within the Scottish Enlightenment in particular, writes Mark G. Spencer. Uncivil Mirth: Ridicule in Enlightenment Britain. Ross Carroll. Princeton University Press. 2021

Geometry Optimizations of Open-Shell Systems with the Fragment Molecular Orbital Method

The ability to perform geometry optimizations on large molecular systems is desirable for both closed- and open-shell species. In this work, the restricted open-shell Hartree–Fock (ROHF) gradients for the fragment molecular orbital (FMO) method are presented. The accuracy of the gradients is tested, and the ability of the method to reproduce adiabatic excitation energies is also investigated. Timing comparisons between the FMO method and full ab initio calculations are also performed, demonstrating the efficiency of the FMO method in modeling large open-shell systems

A PROPOSAL FOR NEW CHRONOSTRATIGRAPHIC STAGE SUBDIVISIONS OF THE UPPER TRIASSIC SERIES

Chronostratigraphic stages that have a short duration are desirable because they identify brief units that can be used to make more detailed and precise age assignments and correlations. Finer-scale substage and zonal subdivisions naturally remain for correlation, but these are outside the formal decision processes of the Subcomission on Triassic Stratigraphy (STS). The longest Phanerozoic stage is the Norian (approximately 18 Myr duration), which is both mismatched in terms of duration with other Phanerozoic stages, and the Lower and Middle Triassic Series, which together are shorter than the Norian Stage. If the Norian was formally divided it would also enhance our understanding of this interval as well as improve chronostratigraphic resolution. We propose the Norian should be raised in rank, and its substages used as new stages. However, such a modification would also require a re-evaluation of the hierarchical position of the Carnian and Rhaetian stages of the Upper Triassic. Given that the Carnian (approximately 10 Myr duration) is one of the longer stages in the Mesozoic it would also benefit with a raised ranking and subdivision to maintain its historical hierarchy with the Norian. We examine three alternative scenarios that raise the rank of the Carnian and Norian (and the Rhaetian Stage) in the chronostratigraphic hierarchy to either series or subseries rank. The existing Upper Triassic substages are also proposed to be raised in rank to stages, allowing formal definition by GSSP boundary stratotypes. The positive and negative issues with any changes in stage and substage hierarchy are examined

System-level Noise Performance of Coherent Imaging Systems

We provide an in-depth analysis of noise considerations in coherent imaging, accounting for speckle and scintillation in addition to “conventional” image noise. Specifically, we formulate closed-form expressions for total effective noise in the presence of speckle only, scintillation only, and speckle combined with scintillation. We find analytically that photon shot noise is uncorrelated with both speckle and weak-to-moderate scintillation, despite their shared dependence on the mean signal. Furthermore, unmitigated speckle and scintillation noise tends to dominate coherent-imaging performance due to a squared mean-signal dependence. Strong coupling occurs between speckle and scintillation when both are present, and we characterize this behavior by fitting a scale factor capable of generating variances in closed form. We verify each of these claims through a series of wave-optics simulations, and we see strong agreement in general between numerical results and theoretical predictions. Our findings allow us to confidently gauge signal-to-noise ratio (SNR) expectations when active illumination produces coherent noise

Climate Change and Biosphere Response: Unlocking the Collections Vault

Natural history collections (NHCs) are an important source of the long-term data needed to understand how biota respond to ongoing anthropogenic climate change. These include taxon occurrence data for ecological modeling, as well as information that can be used to reconstruct mechanisms through which biota respond to changing climates. The full potential of NHCs for climate change research cannot be fully realized until high-quality data sets are conveniently accessible for research, but this requires that higher priority be placed on digitizing the holdings most useful for climate change research (e.g., whole-biota studies, time series, records of intensively sampled common taxa). Natural history collections must not neglect the proliferation of new information from efforts to understand how present-day ecosystems are responding to environmental change. These new directions require a strategic realignment for many NHC holders to complement their existing focus on taxonomy and systematics. To set these new priorities, we need strong partnerships between NHC holders and global change biologists

Quantifying the Lobe Reconnection Rate During Dominant IMF By Periods and Different Dipole Tilt Orientations

Lobe reconnection is usually thought to play an important role in geospace dynamics only when the Interplanetary Magnetic Field (IMF) is mainly northward. This is because the most common and unambiguous signature of lobe reconnection is the strong sunward convection in the polar cap ionosphere observed during these conditions. During more typical conditions, when the IMF is mainly oriented in a dawn-dusk direction, plasma flows initiated by dayside and lobe reconnection both map to high-latitude ionospheric locations in close proximity to each other on the dayside. This makes the distinction of the source of the observed dayside polar cap convection ambiguous, as the flow magnitude and direction are similar from the two topologically different source regions. We here overcome this challenge by normalizing the ionospheric convection observed by the Super Dual Aurora Radar Network (SuperDARN) to the polar cap boundary, inferred from simultaneous observations from the Active Magnetosphere and Planetary Electrodynamics Response Experiment (AMPERE). This new method enable us to separate and quantify the relative contribution of both lobe reconnection and dayside/nightside (Dungey cycle) reconnection during periods of dominating IMF By. Our main findings are twofold. First, the lobe reconnection rate can typically account for 20% of the Dungey cycle flux transport during local summer when IMF By is dominating and IMF Bz ≥ 0. Second, the dayside convection relative to the open/closed boundary is vastly different in local summer versus local winter, as defined by the dipole tilt angle.publishedVersio