The beef industry is facing increasing pressure to adopt sustainable practices, driven by environmental, economic, and social concerns. Designing effective policies that satisfy industry demands while aligning with public interests is a complex challenge. Using a nationally representative survey of 3,001 U.S. residents, we employ a best–worst scaling approach to assess preferences for nine beef sustainability policies. Results reveal consumers prioritize affordability of beef products and welfare of cattle as most important sustainability policies. Conversely, policies addressing greenhouse gas emissions from cattle production are least important, with less than 6% of respondents preferring them.

Dickite and kaolinite are polymorphs of Al4(Si4O10)(OH)8. Dickite traditionally is regarded as hydrothermal, based on field and laboratory evidence. Dickite and kaolinite occur in cavities in phylloid algal limestones, in interstices of biocalcarenites and sandstones, and along joints, fractures, and stylolites, in Pennsylvanian rocks exposed throughout 9600 square miles of southeastern Kansas. The stratigraphic interval of approximately 1100 ft extends from the Fort Scott Limestone (Desmoinesian) through the Lecompton Limestone (Virgilian). The best crystallized dickites are found in porous algal limestones as pockets of glistening white powder composed of well developed pseudohexagonal plates up to 40 μ across. Very well crystallized kaolinites occur similarly, except the crystals are much smaller. Less well crystallized dickites and b-axis disordered kaolinites occur in less porous rocks. Variations in crystal size and morphological development are genetically significant.

Dickite-kaolinite distribution is related to: (1) stratigraphic alternation of limestones and impervious shales; (2) gentle, westward regional dip; (3) thick, mound-like buildups of highly porous algal limestones, miles in length and width; (4) igneous intrusions (early Tertiary?) in Woodson and Wilson counties. Dickite is confined to an elliptical area 125 miles long northeast-southwest, extending 60 miles eastward from the intrusions. Dickite is associated preferentially with porous algal mounds. Kaolinite occurs in less porous rocks within the dickite area, and also is abundant well beyond. Heated groundwaters, possibly mixed with magmatic waters, moved readily up-dip and along strike outward from the intrusions through the conduit-like algal mounds; dickite was deposited from such solutions. Where water movement was restricted or where water had travelled tens of miles from the intrusions, water temperature fell below the limit for dickite crystallization, and kaolinite precipitated instead. Kansas dickite, unlike most other reported dickites, formed in rocks that were neither deeply buried nor extensively altered hydrothermally.

Hexavalent chromium (Cr6+) is a toxic carcinogenic pollutant that might be released by the mining and processing of ultramafic rocks and nickel laterites and which requires permanent removal from the contaminated biosphere. Ultramafic material can also serve as a feedstock for the sequestration of CO2 resulting from the growth of new minerals, raising the intriguing proposition of integrated sequestration of both pollutants, CO2 and chromium, into magnesium carbonates. Such a synergistic process downstream of ore recovery and mineral processing could be an elegant proposition for more sustainable utilisation and management of the Earth's resources. We have therefore carried out an experimental and microanalytical study to investigate potentially suitable carbonate minerals. Uptake of chromium in carbonate phases was determined, followed by identification of the crystalline phases and characterisation of the local structural environment around the incorporated chromium centres. The results suggest that neither nesquehonite nor hydromagnesite have the structural capacity to incorporate Cr6+ or Cr3+ significantly at room temperature. We therefore propose that further research into this technology should focus on laboratory assessments of other phases, such as layered double hyroxides, that have a natural structural capacity to uptake both chromium and CO2.

Eight kaolinite and 2 halloysite samples were analyzed using 27Al magic angle spinning nuclear magnetic resonance (MAS NMR) spectroscopy, chemical analysis and magnetic susceptibility to understand the effect of isomorphously substituted Fe3+ and secondary Fe phases on the NMR signal. Known additions of goethite and hematite were made to determine the response of kaolinite 27Al MAS NMR spectra and sample magnetic susceptibilities.

Results from high field (11.7 T) NMR studies show positive correlations between 1) Fe content, 2) magnetic susceptibility and 3) relative intensity of the spinning side band (SSB) to central band (CB) ratio. No correlation is observed between the mass-corrected NMR spectral intensity and Fe content. Comparative high/low field (11.7 T/8.46 T) NMR studies show a decrease in the relative ratio of line broadening with increasing Fe content. Projected trends of known additions of hematite and goethite versus magnetic susceptibility extrapolate back to zero y intercepts that have Fe concentrations higher than actually measured.

Absolute intensity observations have negative implications for the use of 27Al MAS NMR spectroscopy in assessing Fe-ordering in kaolinites. First, high-energy, short (1/6 of π/2 solutions) pulse sequences do not produce reliable quantitative data needed to assess paramagnetic line-broadening affects caused by different Fe-ordering clustering scenarios. The lack of perfect correlation between SSB/CB, Fe content and magnetic susceptibility indicates that differences exist with respect to 1) the amount of isomorphously substituted Fe, 2) the ordering of the Fe within kaolinite, 3) the concentration of secondary Fe phases and 4) magnetic susceptibility of the secondary Fe assemblage. Variability of line-width ratios at different field strengths indicates an increasing second-order quadrupole effect (SOQE) with increasing Fe. Finally, the difference between the observed Fe content and that predicted from magnetic susceptibility measurements suggest that magnetic domain properties of secondary Fe phases behave differently from Fe domains bound in kaolinite.

The Eocene Huber Formation, exposed in the CFI Hall mine south of Irwinton, in Wilkinson County, Georgia, displays colored zones that are a consequence of an oxidative weathering front. These zones vary from very light gray (gray) to pinkish white (pink) to very pale yellow (cream) (Munsell N8, 5YR 8/2 and 2.5Y 8/2, respectively) with increasing degree of oxidation. A representative sample from each zone was collected and analyzed for its chemical, crystallographic and Raman spectroscopic properties. The comparison of these genetically related samples allowed for a quantitatively accurate assessment of anatase’s contribution to the total TiO2 content. All samples contain ∼1.5 wt.% TiO2. Progressing from gray to pink to cream, anatase contents range from half to nearly all the TiO2. The a lattice parameter for anatase is constant in all three kaolins (3.7916 Å), suggesting a constant 4.6 mol.% isomorphous substitution of Fe for Ti.

Phase characterization and mass-balance considerations of the gray, pink and cream kaolins indicate that ilmenite and pyrite are precursor Ti- and Fe-bearing phases in the gray kaolin that undergo oxidation. Pseudorutile is a proposed intermediate phase resulting from the anodic corrosion of ilmenite. Hematite, goethite and anatase are the dominant end-products via dissolution-precipitation from the reactants pyrite and pseudorutile. The removal of Fe sulfides and organic matter and addition of hematite and goethite causes kaolin colors to change from gray to pink. Oxygen diffusing from groundwater in permeable overlying and underlying formations facilitates a process that probably involves aerobic and anaerobic bacteria that utilize Fe from pyrite, hematite and goethite. We postulate that the end result is the mobilization of Fe by siderophores and a kaolin color change from pink to cream.

This article introduces the first of what will ultimately be two collections of case studies in archaeologist–responsible/responsive artifact collector collaboration. Focused on the United States, the articles in this issue of Advances in Archaeological Practice share the thoughts and experiences of archaeologists representing diverse employment sectors (compliance, agency, museum, and university), artifact collectors, and members of descendant communities. Research areas extend from California to Virginia and from Ohio to the Texas/Mexico border. The breadth of the writers' backgrounds and their focal regions reinforce the wide applicability of collaborative best practices. Every author explicitly treats two subjects: (1) the intersection of their work with the Society for American Archaeology's (SAA) recently published guidelines for ethical professional–collector collaboration, and (2) their own practical suggestions for establishing and nurturing those relationships. This introductory article provides an overview of each of the other contributions, notes how the contributions articulate with the SAA guidelines, and offers its own, mostly philosophical suggestions for prospective members of professional–collector collaborations.

The earliest airborne geophysical campaigns over Antarctica and Greenland in the 1960s and 1970s collected ice penetrating radar data on 35 mm optical film. Early subglacial topographic and englacial stratigraphic analyses of these data were foundational to the field of radioglaciology. Recent efforts to digitize and release these data have resulted in geometric and ice-thickness analysis that constrain subsurface change over multiple decades but stop short of radiometric interpretation. The primary challenge for radiometric analysis is the poorly-characterized compression applied to Z-scope records and the sparse sampling of A-scope records. Here, we demonstrate the information richness and radiometric interpretability of Z-scope records. Z-scope pixels have uncalibrated fast-time, slow-time, and intensity scales. We develop approaches for mapping each of these scales to physical units (microseconds, seconds, and signal to noise ratio). We then demonstrate the application of this calibration and analysis approach to a flight in the interior of East Antarctica with subglacial lakes and to a reflight of an East Antarctic ice shelf that was observed by both archival and modern radar. These results demonstrate the potential use of Z-scope signals to extend the baseline of radiometric observations of the subsurface by decades.

Owing to their ultra-high accelerating gradients, combined with injection inside micrometer-scale accelerating wakefield buckets, plasma-based accelerators hold great potential to drive a new generation of free-electron lasers (FELs). Indeed, the first demonstration of plasma-driven FEL gain was reported recently, representing a major milestone for the field. Several groups around the world are pursuing these novel light sources, with methodology varying in the use of wakefield driver (laser-driven or beam-driven), plasma structure, phase-space manipulation, beamline design, and undulator technology, among others. This paper presents our best attempt to provide a comprehensive overview of the global community efforts towards plasma-based FEL research and development.

We measured the parameter reproducibility and radial electron density profile of capillary discharge waveguides with diameters of 650 $\mathrm{\mu} \mathrm{m}$ to 2 mm and lengths of 9 to 40 cm. To the best of the authors’ knowledge, 40 cm is the longest discharge capillary plasma waveguide to date. This length is important for $\ge$10 GeV electron energy gain in a single laser-driven plasma wakefield acceleration stage. Evaluation of waveguide parameter variations showed that their focusing strength was stable and reproducible to $<0.2$% and their average on-axis plasma electron density to $<1$%. These variations explain only a small fraction of laser-driven plasma wakefield acceleration electron bunch variations observed in experiments to date. Measurements of laser pulse centroid oscillations revealed that the radial channel profile rises faster than parabolic and is in excellent agreement with magnetohydrodynamic simulation results. We show that the effects of non-parabolic contributions on Gaussian pulse propagation were negligible when the pulse was approximately matched to the channel. However, they affected pulse propagation for a non-matched configuration in which the waveguide was used as a plasma telescope to change the focused laser pulse spot size.

Magnetic wave perturbations are observed in the solar wind and in the vicinity of Earth's bow shock. For such environments, recent work on magnetic pumping with electrons trapped in the magnetic perturbations has demonstrated the possibility of efficient energization of superthermal electrons. Here we also analyse the energization of such energetic electrons for which the transit time through the system is short compared with time scales associated with the magnetic field evolution. In particular, considering an idealized magnetic configuration we show how trapping/detrapping of energetic magnetized electrons can cause effective parallel velocity ($v_{\parallel }$-) diffusion. This parallel diffusion, combined with naturally occurring mechanisms known to cause pitch angle scattering, such as whistler waves, produces enhanced heating rates for magnetic pumping. We find that at low pitch angle scattering rates, the combined mechanism enhances the heating beyond the predictions of the recent theory for magnetic pumping with trapped electrons.

Subglacial topography is an important feature in numerous ice-sheet analyses and can drive the routing of water at the bed. Bed topography is primarily measured with ice-penetrating radar. Significant gaps, however, remain in data coverage that require interpolation. Topographic interpolations are typically made with kriging, as well as with mass conservation, where ice flow dynamics are used to constrain bed geometry. However, these techniques generate bed topography that is unrealistically smooth at small scales, which biases subglacial water flowpath models and makes it difficult to rigorously quantify uncertainty in subglacial drainage patterns. To address this challenge, we adapt a geostatistical simulation method with probabilistic modeling to stochastically simulate bed topography such that the interpolated topography retains the spatial statistics of the ice-penetrating radar data. We use this method to simulate subglacial topography using mass conservation topography as a secondary constraint. We apply a water routing model to each of these realizations. Our results show that many of the flowpaths significantly change with each topographic realization, demonstrating that geostatistical simulation can be useful for assessing confidence in subglacial flowpaths.

Background: Carbapenem-resistant Enterobacteriaceae (CRE) are an important cause of healthcare-associated infections (HAIs) in human hospitals. The Philadelphia Department of Public Health (PDPH) made CRE reportable in April 2018. In May 2019, the Matthew J. Ryan Veterinary Hospital (MJRVH) reported an NDM-5 Escherichia coli cluster in companion animals to the PDPH. In total, 15 infected animals (14 dogs and 1 cat) were reported between July 2018 and June 2019, with no new infections after June 2019. Limited literature is available on the prevalence of CRE in companion animals, and recommendations for dealing with CRE infections currently target human healthcare settings. Methods: A collaborative containment response included assessing interspecies transmission to veterinary staff and a comprehensive evaluation of the infection control program at MJRVH. MJRVH notified all owners of affected animals verbally and via notification letters with PDPH recommendations for CRE colonization screening of high-risk individuals. CRE screening of exposed high-risk employees was conducted by the University of Pennsylvania Occupational Health service and PDPH. Human rectal swabs were analyzed at the Antibiotic Resistance Laboratory Network (ARLN) Maryland Laboratory. PDPH were invited to conduct an onsite infection control assessment and to suggest improvements. Results: No pet owners self-identified in high-risk groups to be screened. In total, 10 high-risk staff were screened, and no colonized individuals were detected. Recommendations made by the PDPH to MJRVH included improvement of infection prevention and control policies (eg, consolidation of the infection control manual and identification of lead staff member), improvement in hand hygiene (HH) compliance (eg, increasing amount of HH supplies), improvement of environment of care (eg, decluttering and evaluation of mulched animal relief area), and improvement of respiratory care processes (eg, standardization of care policies). MJRVH made substantial improvements across recommendation areas including revision of infection control manual, creation of a full-time infection preventionist position, individual alcohol hand sanitizers for patient cages, and environmental decluttering and decontamination. PDPH and MJRVH maintained frequent communication about infection control improvements. Conclusions: No positive transmission to high-risk staff members suggest that, like in human healthcare facilities, transmission of CRE to caretakers may not be a common event. Stronger communication and collaboration is required from Departments of Public Health (DPH) to the veterinary profession regarding the reporting requirements of emerging pathogens such as CRE. Veterinary facilities should view DPH as a valuable resource for recommendations to fill in gaps that exist in infection control “best practices,” particularly for novel pathogens in veterinary settings.

Funding: None

Disclosures: Jane M. Gould reports that her spouse receives salary from Incyte.

A new optimized quasi-helically symmetric configuration is described that has the desirable properties of improved energetic particle confinement, reduced turbulent transport by three-dimensional shaping and non-resonant divertor capabilities. The configuration presented in this paper is explicitly optimized for quasi-helical symmetry, energetic particle confinement, neoclassical confinement and stability near the axis. Post optimization, the configuration was evaluated for its performance with regard to energetic particle transport, ideal magnetohydrodynamic stability at various values of plasma pressure and ion temperature gradient instability induced turbulent transport. The effects of discrete coils on various confinement figures of merit, including energetic particle confinement, are determined by generating single-filament coils for the configuration. Preliminary divertor analysis shows that coils can be created that do not interfere with expansion of the vessel volume near the regions of outgoing heat flux, thus demonstrating the possibility of operating a non-resonant divertor.

The plasma channel formation in the focus of a knife-like nanosecond laser pulse irradiating a gas target is studied theoretically, and in gas-dynamics computer simulations. The distribution of the electromagnetic field in the focus region, obtained analytically, is used to calculate the energy deposition in the plasma, which then is implemented in the magnetohydrodynamic computer code. The modelling of the channel evolution shows that the plasma profile, which can guide the laser pulse, is formed by the tightly focused short knife-like lasers. The results of the simulations show that a proper choice of the convergence angle of a knife-like laser beam (determined by the focal length of the last cylindrical lens), and laser pulse duration may provide a sufficient degree of azimuthal symmetry of the formed plasma channel.

Airborne radio-echo sounding (RES) surveys are widely used to measure ice-sheet bed topography. Measuring bed topography as accurately and widely as possible is of critical importance to modelling ice dynamics and hence to constraining better future ice response to climate change. Measurement accuracy of RES surveys is influenced both by the geometry of bed topography and the survey design. Here we develop a novel approach for simulating RES surveys over glaciated terrain, to quantify the sensitivity of derived bed elevation to topographic geometry. Furthermore, we investigate how measurement errors influence the quantification of glacial valley geometry. We find a negative bias across RES measurements, where off-nadir return measurement error is typically −1.8 ± 11.6 m. Topographic highlands are under-measured an order of magnitude more than lowlands. Consequently, valley depth and cross-sectional area are largely under-estimated. While overall estimates of ice thickness are likely too high, we find large glacier valley cross-sectional area to be under-estimated by −2.8 ± 18.1%. Therefore, estimates of ice flux through large outlet glaciers are likely too low when this effect is not taken into account. Additionally, bed mismeasurements potentially impact our appreciation of outlet-glacier stability.

Basal units – visibly distinct englacial structures near the ice-bed interface – warrant investigation for a number of reasons. Many are of unknown composition and origin, characteristics that could provide substantial insight into subglacial processes and ice-sheet history. Their significance, moreover, is not limited to near-bed depths; these units appear to dramatically influence the flow of surrounding ice. In order to enable improved characterization of these features, we develop and apply an algorithm that allows for the automatic detection of basal units. We use a tunable layer-optimized SAR processor to distinguish these structures from the bed, isochronous englacial layers and the ice-sheet surface, presenting a conceptual framework for the use of radio-echo character in the identification of ice-sheet features. We also outline a method by which our processor could be used to place observational constraints on basal units’ configuration, composition and provenance.

The Antarctic Impulsive Transient Antenna (ANITA) balloon experiment was designed to detect radio signals initiated by high-energy neutrinos and cosmic ray (CR) air showers. These signals are typically discriminated by the polarization and phase inversions of the radio signal. The reflected signal from CRs suffer phase inversion compared to a direct ‘tau neutrino’ event. In this paper, we study subsurface reflection, which can occur without phase inversion, in the context of the two anomalous up-going events reported by ANITA. It is found that subsurface layers and firn density inversions may plausibly account for the events, while ice fabric layers and wind ablation crusts could also play a role. This hypothesis can be tested with radar surveying of the Antarctic region in the vicinity of the anomalous ANITA events. Future experiments should not use phase inversion as a sole criterion to discriminate between down-going and up-going events, unless the subsurface reflection properties are well understood.

Radar sounding is a powerful geophysical approach for characterizing the subsurface conditions of terrestrial and planetary ice masses at local to global scales. As a result, a wide array of orbital, airborne, ground-based, and in situ instruments, platforms and data analysis approaches for radioglaciology have been developed, applied or proposed. Terrestrially, airborne radar sounding has been used in glaciology to observe ice thickness, basal topography and englacial layers for five decades. More recently, radar sounding data have also been exploited to estimate the extent and configuration of subglacial water, the geometry of subglacial bedforms and the subglacial and englacial thermal states of ice sheets. Planetary radar sounders have observed, or are planned to observe, the subsurfaces and near-surfaces of Mars, Earth's Moon, comets and the icy moons of Jupiter. In this review paper, and the thematic issue of the Annals of Glaciology on ‘Five decades of radioglaciology’ to which it belongs, we present recent advances in the fields of radar systems, missions, signal processing, data analysis, modeling and scientific interpretation. Our review presents progress in these fields since the last radio-glaciological Annals of Glaciology issue of 2014, the context of their history and future prospects.