Frequency Following Imaging of Electric Fields from Resonant Superconducting Devices using a Scanning Near-Field Microwave Microscope

We have developed a scanning near-field microwave microscope that operates at cryogenic temperatures. Our system uses an open-ended coaxial probe with a 200 mm inner conductor diameter and operates from 77 to 300 K in the 0.01-20 GHz frequency range. In this paper, we present microwave images of the electric field distribution above a Tl2Ba2CaCu2O8 microstrip resonator at 77 K, measured at several heights. In addition, we describe the use of a frequency-following circuit to study the influence of the probe on the resonant frequency of the device.Comment: 4 pages, postscript file with 6 figures conference proceeding for the Applied Superconductivity Conference 199

Microwave Near-Field Imaging of Electric Fields in a Superconducting Microstrip Resonator

We describe the use of a cryogenic near-field scanning microwave microscope to image microwave electric fields from superconducting and normal-metal microstrip resonators. The microscope employs an open-ended coaxial probe and operates from 77 to 300 K in the 0.01-20 GHz frequency range with a spatial resolution of about 200 mm. We describe the operation of the system and present microwave images of Cu and Tl2Ba2CaCu2O8 microstrip resonators, showing standing wave patterns at the fundamental and second harmonic frequencies.Comment: 9 pages, 3 eps figure

High lability of sexual system over 250 million years of evolution in morphologically conservative tadpole shrimps

Background Sexual system is a key factor affecting the genetic diversity, population structure, genome structure and the evolutionary potential of species. The sexual system androdioecy – where males and hermaphrodites coexist in populations – is extremely rare, yet is found in three crustacean groups, barnacles, a genus of clam shrimps Eulimnadia, and in the order Notostraca, the tadpole shrimps. In the ancient crustacean order Notostraca, high morphological conservatism contrasts with a wide diversity of sexual systems, including androdioecy. An understanding of the evolution of sexual systems in this group has been hampered by poor phylogenetic resolution and confounded by the widespread occurrence of cryptic species. Here we use a multigene supermatrix for 30 taxa to produce a comprehensive phylogenetic reconstruction of Notostraca. Based on this phylogenetic reconstruction we use character mapping techniques to investigate the evolution of sexual systems. We also tested the hypothesis that reproductive assurance has driven the evolution of androdioecy in Notostraca. Results Character mapping analysis showed that sexual system is an extremely flexible trait within Notostraca, with repeated shifts between gonochorism and androdioecy, the latter having evolved a minimum of five times. In agreement with the reproductive assurance hypothesis androdioecious notostracans are found at significantly higher latitudes than gonochoric ones indicating that post glacial re-colonisation may have selected for the higher colonisation ability conferred by androdioecy. Conclusions In contrast to their conserved morphology, sexual system in Notostraca is highly labile and the rare reproductive mode androdioecy has evolved repeatedly within the order. Furthermore, we conclude that this lability of sexual system has been maintained for at least 250 million years and may have contributed to the long term evolutionary persistence of Notostraca. Our results further our understanding of the evolution of androdioecy and indicate that reproductive assurance is a recurrent theme involved in the evolution of this sexual system

Maternal nutrient restriction in guinea pigs leads to fetal growth restriction with increased brain apoptosis

Background: We determined whether maternal nutrient restriction (MNR) in guinea pigs leading to fetal growth restriction (FGR) impacts cell death in the brain with implications for neurodevelopmental adversity. Methods: Guinea pigs were fed ad libitum (Control) or 70% of the control diet before pregnancy, switching to 90% at mid-pregnancy (MNR). Fetuses were necropsied near term and brain tissues processed for necrosis (H&E), apoptosis (TUNEL), and pro- (Bax) and anti- (Bcl-2 and Grp78) apoptotic protein immunoreactivity. Results: FGR-MNR fetal and brain weights were decreased 38% and 12%, respectively, indicating brain sparing but with brains still smaller. While necrosis remained unchanged, apoptosis was increased in the white matter and hippocampus in the FGR brains, and control and FGR-related apoptosis were increased in males for most brain areas. Bax was increased in the CA4 and Bcl-2 was decreased in the dentate gyrus in the FGR brains supporting a role in the increased apoptosis, while Grp78 was increased in the FGR females, possibly contributing to the sex-related differences. Conclusions: MNR-induced FGR results in increased brain apoptosis with regional and sex-related differences that may contribute to the reduction in brain area size reported clinically and increased risk in FGR males for later neurodevelopmental adversity

Supreme Court Brief Amicus Curiae of Administrative Law Scholars in Support of Neither Party

This brief on behalf of 29 administrative law scholars takes no position on whether Administrative Law Judges (ALJs) are employees or inferior officers. It urges the Court to issue an opinion that respects the decision that Congress made unanimously in 1946 to enact numerous statutory safeguards that assure that ALJs have decisional independence from the agencies where they work while assuring that agencies retain control over the policy content and legal basis for any decision made in an adjudication in which an ALJ presides. The brief describes the fifteen years of study and deliberation that led to the unanimous decision of Congress to enact the Administrative Procedure Act (APA) in 1946. It describes the particular attention that Congress devoted to the critical task of providing ALJs with the combination of statutory safeguards that minimize the risk that they will favor the agencies for whom they adjudicate cases while assuring that the agencies retain control of the policy content of any decision made in such an adjudication. It then describes the series of opinions the Supreme Court issued during the 1950s in which the Justices unanimously praised the provisions of the APA that assure that ALJs conduct adjudicatory hearings in an unbiased manner, explained the importance of those statutory provisions in protecting the values reflected in the Due Process Clause, and urged Congress to make those safeguards applicable to all agency adjudications. It concludes by urging the Court to issue an opinion that respects the decision that Congress made in 1946 to insulate ALJs from potential sources of pro-agency bias by including in the APA a combination of provisions that confer decisional independence on ALJs

Beyond Walkers in Stochastic Quantum Chemistry: Reducing Error using Fast Randomized Iteration

We introduce a family of methods for the full configuration interaction problem in quantum chemistry, based on the fast randomized iteration (FRI) framework [L.-H. Lim and J. Weare, SIAM Rev. 59, 547 (2017)]. These methods, which we term "FCI-FRI," stochastically impose sparsity during iterations of the power method and can be viewed as a generalization of full configuration interaction quantum Monte Carlo (FCIQMC) without walkers. In addition to the multinomial scheme commonly used to sample excitations in FCIQMC, we present a systematic scheme where excitations are not sampled independently. Performing ground-state calculations on five small molecules at fixed cost, we find that the systematic FCI-FRI scheme is 11 to 45 times more statistically efficient than the multinomial FCI-FRI scheme, which is in turn 1.4 to 178 times more statistically efficient than the original FCIQMC algorithm.Comment: 19 pages, 7 figure

Understanding the agglomerate crystallisation of hexamine through X-ray microscopy and crystallographic modelling

© 2022 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/The detailed molecular-scale mechanism of the growth of organic crystals underpins a diversity of phenomena, such as the isolation and purification of high-quality materials for the pharmaceutical and fine chemical sectors. Recent advances in X-ray Microscopy (XRM) and complementary diffraction contrast tomography (DCT) have enabled the detailed characterisation of the micro-structure of hexamine agglomerates. Detailed XRM analysis of the growth history and micro-structure of such agglomerates reveals a highly orientated epitaxial inter-relationship between their constituent micro-crystallites. This is found to be consistent with a secondary nucleation growth mechanism associated with re-growth at the 3-fold corner sites within the crystals’ dominant {1 1 0} dodecahedral morphology. The agglomeration appears to heal upon further growth as the aligned agglomerated micro-crystals connect and fuse together but, in doing so, pockets of inter-crystallite mother liquor become trapped forming a symmetric pattern of solvent inclusions. The mechanistic origin of this phenomenon is rationalised with respect to historical data together with an analysis of the solid-state chemistry of the compound through the development of a ‘snow flake’ model. The latter draws upon hexamine's propensity for edge growth instabilities with increasing crystal size as well as its tendency for unstable growth at the facet corners along the 〈1 1 1〉 directions, a situation compounded by the lack of growth-promoting dislocations at the centers of the {1 1 0} habit surfaces. The agglomerative mechanism presented here could apply to other high symmetry crystal systems, particularly those whose crystal structures involve centred Bravais lattices and where the dominant inter-molecular interactions are angled towards the facet edges.Peer reviewe

Ohio Economic Insects and Related Anthropods

PDF pages: 3

Synthesis of nuclear waste simulants by reaction precipitation: formation of caesium phosphomolybdate, zirconium molybdate and morphology modification with citratomolybdate complex

Caesium phosphomolybdate (CsPMoO·xHO) and zirconium molybdate ([ZrMoO(OH)]·2HO) solids are known to precipitate out from highly active liquors (HAL) during reprocessing of spent nuclear fuel. Here, a new synthesis for these simulants is reported; with the initial step producing spherical ceasium phosphomolybdate particles, which can then be converted into cubic Zirconium molybdate. Additionally, the addition of citric acid prior to the formation of the zirconium salt is investigated. In this case, a citratomolybdate complex is generated, leading to the synthesis of elongated cuboidal zirconium citratomolybdate ([ZrMoO(OH)]·2HO·[(MoO)O(cit)]). A key focus of this study is to explore the optimisation of reaction conditions to create a controlled environment for the particles to form with high conversion rates and with desired shape properties. Elemental and structural characterisation of the particles at various points during the synthesis, as well as post-synthesis, was undertaken to provide further insights. Ultimately, it is of importance to determine the mechanism of how these simulants are formed within the components in HAL. Establishing the influence of particle properties on HAL behaviour is key for current processing, post operational clean out (POCO) and life-time assessment of the nuclear waste facilities