Prophecy and Anti-Popery in Victorian London: John Cumming Reconsidered

John Cumming (1807-1881) was the popular minister of the Crown Court Church of Scotland in London\u27s Covent Garden. This article examines his views on the end times and the Roman Catholic Church, two of the favorite subjects of his preaching

Drift ratchets as biomimetic filters

Diatoms are microscopic, phototrophic, unicellular algae encased in a porous, rigid, siliceous, cell wall known as a frustule and they inhabit the euphotic zones in bodies of seawater and freshwater globally. It is not yet fully understood how diatoms compete with swimming microorganisms for nutrients in their environment. It is believed that the frustule does play a role in giving them a competitive advantage, however, the function of the diatoms’ frustule is not yet fully understood. Among other functions it has been proposed that the frustule acts like a filter for the diatom, sorting nutrients from harmful entities such as pathogens, poisons, colloids and pollutants, from their natural environment. As a result of the micro- and nanoscopic nature of the frustule and its features, diffusion is thought to play an important role in the frustules filtering capabilities. It has been proposed that specific centric species of diatom employ the drift ratchet mechanism to sort and control mass transport towards and away from the diatom cell. This research has determined that this is unlikely due to the size and configuration of the diatom girdle band pores. Instead, a new theory is presented herein, termed “Hydrodynamic Immunity”, in which diatoms use diffusiophoresis to separate nutrients from harmful entities. In conjunction with this work the dimensionless numbers critical for dynamic similarity analysis of a drift ratchet are determined to allow for easy comparison between dynamically similar experiments. Finally, a novel hydrodynamic drift ratchet microfluidic device was designed and fabricated as a proof-of-concept to prove definitively whether the drift ratchet mechanism can be generated in an experimental environment, following inconclusive findings from past research experiments. This remains unresolved due to experimental complications; however improvements are suggested to ensure future work is successful at recreating a drift ratchet in experiments

Oral Interview with Alejandra Best

I interviewed Mrs. Best using Zoom. She lives in Cincinnati, Ohio, but was born in Mexico City, Mexico. During the interview Mrs. Best was at her house, in the living room where she used her computer. The setting was very calm because she was at a tranquil place without any distractions. Even though the interview was conducted by Zoom, we were able to talk peacefully. Mrs. Best talked about her life and experiences in the United States, and Cincinnati and the transitions that she made during her life. She also spoke about important Mexican traditions and what Mrs. Best values most in life

Wilson ratio of a Tomonaga-Luttinger liquid in a spin-1/2 Heisenberg ladder

Using micromechanical force magnetometry, we have measured the magnetization of the strong-leg spin-1/2 ladder compound (C$_7$H$_{10}$N)$_2$CuBr$_2$ at temperatures down to 45 mK. Low-temperature magnetic susceptibility as a function of field exhibits a maximum near the critical field H_c at which the magnon gap vanishes, as expected for a gapped one-dimensional antiferromagnet. Above H_c a clear minimum appears in the magnetization as a function of temperature as predicted by theory. In this field region, the susceptibility in conjunction with our specific heat data yields the Wilson ratio R_W. The result supports the relation R_W=4K, where K is the Tomonaga-Luttinger-liquid parameter

Permutationally Invariant Networks for Enhanced Sampling (PINES): Discovery of Multi-Molecular and Solvent-Inclusive Collective Variables

The typically rugged nature of molecular free energy landscapes can frustrate efficient sampling of the thermodynamically relevant phase space due to the presence of high free energy barriers. Enhanced sampling techniques can improve phase space exploration by accelerating sampling along particular collective variables (CVs). A number of techniques exist for data-driven discovery of CVs parameterizing the important large scale motions of the system. A challenge to CV discovery is learning CVs invariant to symmetries of the molecular system, frequently rigid translation, rigid rotation, and permutational relabeling of identical particles. Of these, permutational invariance have proved a persistent challenge in frustrating the the data-driven discovery of multi-molecular CVs in systems of self-assembling particles and solvent-inclusive CVs for solvated systems. In this work, we integrate Permutation Invariant Vector (PIV) featurizations with autoencoding neural networks to learn nonlinear CVs invariant to translation, rotation, and permutation, and perform interleaved rounds of CV discovery and enhanced sampling to iteratively expand sampling of configurational phase space and obtain converged CVs and free energy landscapes. We demonstrate the Permutationally Invariant Network for Enhanced Sampling (PINES) approach in applications to the self-assembly of a 13-atom Argon cluster, association/dissociation of a NaCl ion pair in water, and hydrophobic collapse of a C45H92 n-pentatetracontane polymer chain. We make the approach freely available as a new module within the PLUMED2 enhanced sampling libraries

Dynamics of the two-dimensional S=1/2 dimer system (C5H6N2F)2CuCl4

Inelastic neutron scattering was used to study a quantum S=1/2 antiferromagnetic Heisenberg system-Bis(2-amino-5-fluoropyridinium) Tetrachlorocuprate(II). The magnetic excitation spectrum was shown to be dominated by long-lived excitations with an energy gap as 1.07(3) meV. The measured dispersion relation is consistent with a simple two-dimensional square lattice of weakly-coupled spin dimers. Comparing the data to a random phase approximation treatment of this model gives the intra-dimer and inter-dimer exchange constants J=1.45(2) meV and J'=0.31(3) meV, respectively.Comment: 4 pages, 4 figure

Production technology of Nabataean painted pottery compared with that of Roman terra sigillata

The Nabataeans, who founded the city of Petra (southern Jordan) in the late first millennium BCE, are noted for the production of a distinctive very fine pottery with painted decoration and a wall thickness sometimes as little as 1.5 mm; this pottery appears largely locally made and not widely circulated. Using a combination of OM, SEM with attached EDS, surface XRF, and XRD, it is shown that the Nabataean fine pottery bodies were produced using semi-calcareous clays which were fired to temperatures of about 950 °C. In contrast, published data indicate that contemporary and in many ways apparently functionally equivalent Roman terra sigillata, which was traded throughout the Roman Empire, was produced using fully-calcareous clays which were fired to temperatures in the range 1000–1100 °C. Furthermore, the high gloss slip applied to Roman terra sigillata is fully vitrified whereas the red-painted decoration applied to the Nabataean pottery is unvitrified. The more robust Roman terra sigillata is therefore better suited as tableware for serving and consuming food than would be the case for Nabataean fine pottery, and would be a more successful export material