Concept of Operations Visualization for Ares I Production

Establishing Computer Aided Design models of the Ares I production facility, tooling and vehicle components and integrating them into manufacturing visualizations/simulations allows Boeing and NASA to collaborate real time early in the design/development cycle. This collaboration identifies cost effective and lean solutions that can be easily shared with Ares stakeholders (e.g., other NASA Centers and potential science users). These Ares I production visualizations and analyses by their nature serve as early manufacturing improvement precursors for other Constellation elements to be built at the Michoud Assembly Facility such as Ares V and the Altair Lander. Key to this Boeing and Marshall Space Flight Center collaboration has been the use of advanced virtual manufacturing tools to understand the existing Shuttle era infrastructure and trade potential modifications to support Ares I production. These approaches are then used to determine an optimal manufacturing configuration in terms of labor efficiency, safety and facility enhancements. These same models and tools can be used in an interactive simulation of Ares I and V flight to the Space Station or moon to educate the human space constituency (e.g., government, academia, media and the public) in order to increase national and international understanding of Constellation goals and benefits

Three-coordinate iron(II) expanded ring N-heterocyclic carbene complexes

A sterically demanding seven-membered expanded ring N-heterocyclic carbene (NHC) ligand allows access to rare examples of three-coordinate iron(II)-NHC complexes incorporating only halide coligands of the general formula [Fe(NHC)X 2 ] (NHC = 7-DiPP; X = Br (1) Cl (2)). Reducing the steric influence of the ancillary NHC ligand through modulation of the N-aryl substituents leads to either four- or three-coordinate complexes of the general formula [Fe(NHC)Br 2 (THF)] (3) or [Fe(NHC)Br 2 ] (4) (NHC = 7-Mes), dependent upon the solvent of recrystallization. The further reduction of NHC steric influence results in four-coordinate geometries at iron in the form of the dimeric species [Fe(NHC)Br(μ-Br)] 2 (5) or [Fe(NHC)Br 2 (THF)] (6) (NHC = SDiPP), again dependent upon the solvent of recrystallization. Compounds 1-6 have been analyzed by 1 H NMR spectroscopy, X-ray crystallography, elemental microanalysis, Mössbauer spectroscopy (for 1 and 3-5), and Evans method magnetic susceptibility. In addition to these measurements the three-coordinate species 1 and 4 have been further analyzed by SQUID magnetometry and CASSCF calculations, which show significant magnetic anisotropy that is extremely sensitive to the coordination geometry

Short-term genome stability of serial Clostridium difficile ribotype 027 isolates in an experimental gut model and recurrent human disease

Copyright: © 2013 Eyre et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are creditedClostridium difficile whole genome sequencing has the potential to identify related isolates, even among otherwise indistinguishable strains, but interpretation depends on understanding genomic variation within isolates and individuals.Serial isolates from two scenarios were whole genome sequenced. Firstly, 62 isolates from 29 timepoints from three in vitro gut models, inoculated with a NAP1/027 strain. Secondly, 122 isolates from 44 patients (2–8 samples/patient) with mostly recurrent/on-going symptomatic NAP-1/027 C. difficile infection. Reference-based mapping was used to identify single nucleotide variants (SNVs).Across three gut model inductions, two with antibiotic treatment, total 137 days, only two new SNVs became established. Pre-existing minority SNVs became dominant in two models. Several SNVs were detected, only present in the minority of colonies at one/two timepoints. The median (inter-quartile range) [range] time between patients’ first and last samples was 60 (29.5–118.5) [0–561] days. Within-patient C. difficile evolution was 0.45 SNVs/called genome/year (95%CI 0.00–1.28) and within-host diversity was 0.28 SNVs/called genome (0.05–0.53). 26/28 gut model and patient SNVs were non-synonymous, affecting a range of gene targets.The consistency of whole genome sequencing data from gut model C. difficile isolates, and the high stability of genomic sequences in isolates from patients, supports the use of whole genome sequencing in detailed transmission investigations.Peer reviewe

Political Ideology and Judicial Administration: Evidence from the COVID-19 Pandemic

We study the effect of political ideology on the administration of the judiciary by investigating how the chief judges of federal district courts set courthouse policies in response to the COVID-19 pandemic. To do so, we use novel data on the geographic boundaries of federal courts and on the contents of pandemic orders. We account for state and local conditions and policies by leveraging district courts in states that have multiple judicial districts and that have courthouses in multiple counties, and we isolate the effect of chief ideology by using simulations that difference out unobserved district-level effects. We find no consistent evidence that the ideology of chief judges influenced courthouse closures and the authorization of a law allowing for remote proceedings, but we find strong evidence that Republican-appointed chief judges were less likely to require masks and more likely to suspend in-person trials

Predicting the Detectability of Thin Gaseous Plumes in Hyperspectral Images Using Basis Vectors

This paper describes a new method for predicting the detectability of thin gaseous plumes in hyperspectral images. The novelty of this method is the use of basis vectors for each of the spectral channels of a collection instrument to calculate noise-equivalent concentration-pathlengths instead of matching scene pixels to absorbance spectra of gases in a library. This method provides insight into regions of the spectrum where gas detection will be relatively easier or harder, as influenced by ground emissivity, temperature contrast, and the atmosphere. Our results show that data collection planning could be influenced by information about when potential plumes are likely to be over background segments that are most conducive to detection

Environmental flow requirements of estuaries: providing resilience to current and future climate and direct anthropogenic changes

Estuaries host unique biodiversity and deliver a range of ecosystem services at the interface between catchment and the ocean. They are also among the most degraded ecosystems on Earth. Freshwater flow regimes drive ecological processes contributing to their biodiversity and economic value, but have been modified extensively in many systems by upstream water use. Knowledge of freshwater flow requirements for estuaries (environmental flows or E-flows) lags behind that of rivers and their floodplains. Generalising estuarine E-flows is further complicated by responses that appear to be specific to each system. Here we critically review the E-flow requirements of estuaries to 1) identify the key ecosystem processes (hydrodynamics, salinity regulation, sediment dynamics, nutrient cycling and trophic transfer, and connectivity) modulated by freshwater flow regimes, 2) identify key drivers (rainfall, runoff, temperature, sea level rise and direct anthropogenic) that generate changes to the magnitude, quality and timing of flows, and 3) propose mitigation strategies (e.g., modification of dam operations and habitat restoration) to buffer against the risks of altered freshwater flows and build resilience to direct and indirect anthropogenic disturbances. These strategies support re-establishment of the natural characteristics of freshwater flow regimes which are foundational to healthy estuarine ecosystems

Exquisite sensitivity of the ligand field to solvation and donor polarisability in coordinatively saturated lanthanide complexes

Crystallographic, emission and NMR studies of a series of C3-symmetric, nine-coordinate substituted pyridyl triazacyclononane Yb(III) and Eu(III) complexes reveal the impact of local solvation and ligand dipolar polarisability on ligand field strength, leading to dramatic variations in pseudocontact NMR shifts and emission spectral profiles, giving new guidance for responsive NMR and spectral probe design