Alteration history of Séítah formation rocks inferred by PIXL x-ray fluorescence, x-ray diffraction, and multispectral imaging on Mars.

Collocated crystal sizes and mineral identities are critical for interpreting textural relationships in rocks and testing geological hypotheses, but it has been previously impossible to unambiguously constrain these properties using in situ instruments on Mars rovers. Here, we demonstrate that diffracted and fluoresced x-rays detected by the PIXL instrument (an x-ray fluorescence microscope on the Perseverance rover) provide information about the presence or absence of coherent crystalline domains in various minerals. X-ray analysis and multispectral imaging of rocks from the Séítah formation on the floor of Jezero crater shows that they were emplaced as coarsely crystalline igneous phases. Olivine grains were then partially dissolved and filled by finely crystalline or amorphous secondary silicate, carbonate, sulfate, and chloride/oxychlorine minerals. These results support the hypothesis that Séítah formation rocks represent olivine cumulates altered by fluids far from chemical equilibrium at low water-rock ratios.

Rapid implementation of telegenetic services during the COVID-19 pandemic allowed continuing patient access, but not equally for all.

Telegenetics is the use of telemedicine to deliver clinical genetic services to patients. During the COVID-19 public health emergency (PHE), telegenetics was essential for the Center of Personalized Genetic Healthcare (CPGH). This study reviews and analyzes in the context of the RE-AIM framework CPGH's rapid implementation of telegenetics and its impact. We conducted a chart review of all out-patient telegenetics encounters scheduled in CPGH during the first five weeks of the COVID-19 PHE. Data analyzed included demographics; number of encounters scheduled; subspecialties and providers; outcome of encounter (completed, cancelled, no- show); and telehealth platform used. Data were compared to data for out-patient encounters in 2019. In the first five weeks of the COVID-19 PHE, 465 virtual visits were scheduled and 428 were completed, involving all six subspecialties and 86% of CPGH providers. The no-show plus cancellation rate was significantly lower than in 2019. By week four, CPGH's virtual visit volume was 82% of its out-patient volume during the same time period in 2019. Patients over 60 and Black patients were significantly more likely to use phone-audio only appointments. CPGH rapidly implemented telegenetic services to continue providing care to patients. We identified success factors that enabled this. However, our analysis also identified a possible "digital divide" for Black and older patients.

Investigating Habitability with an Integrated Rock-Climbing Robot and Astrobiology Instrument Suite.

A prototype rover carrying an astrobiology payload was developed and deployed at analog field sites to mature generalized system architectures capable of searching for biosignatures in extreme terrain across the Solar System. Specifically, the four-legged Limbed Excursion Mechanical Utility Robot (LEMUR) 3 climbing robot with microspine grippers carried three instruments: a micro-X-ray fluorescence instrument based on the Mars 2020 mission's Planetary Instrument for X-ray Lithochemistry provided elemental chemistry; a deep-ultraviolet fluorescence instrument based on Mars 2020's Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals mapped organics in bacterial communities on opaque substrates; and a near-infrared acousto-optic tunable filter-based point spectrometer identified minerals and organics in the 1.6-3.6 µm range. The rover also carried a light detection and ranging and a color camera for both science and navigation. Combined, this payload detects astrobiologically important classes of rock components (elements, minerals, and organics) in extreme terrain, which, as demonstrated in this work, can reveal a correlation between textural biosignatures and the organics or elements expected to preserve them in a habitable environment. Across >10 field tests, milestones were achieved in instrument operations, autonomous mobility in extreme terrain, and system integration that can inform future planetary science mission architectures. Contributions include (1) system-level demonstration of mock missions to the vertical exposures of Mars lava tube caves and Mars canyon walls, (2) demonstration of multi-instrument integration into a confocal arrangement with surface scanning capabilities, and (3) demonstration of automated focus stacking algorithms for improved signal-to-noise ratios and reduced operation time.

Photogeologic Map of the Perseverance Rover Field Site in Jezero Crater Constructed by the Mars 2020 Science Team.

The Mars 2020 Perseverance rover landing site is located within Jezero crater, a ∼ 50 km diameter impact crater interpreted to be a Noachian-aged lake basin inside the western edge of the Isidis impact structure. Jezero hosts remnants of a fluvial delta, inlet and outlet valleys, and infill deposits containing diverse carbonate, mafic, and hydrated minerals. Prior to the launch of the Mars 2020 mission, members of the Science Team collaborated to produce a photogeologic map of the Perseverance landing site in Jezero crater. Mapping was performed at a 1:5000 digital map scale using a 25 cm/pixel High Resolution Imaging Science Experiment (HiRISE) orthoimage mosaic base map and a 1 m/pixel HiRISE stereo digital terrain model. Mapped bedrock and surficial units were distinguished by differences in relative brightness, tone, topography, surface texture, and apparent roughness. Mapped bedrock units are generally consistent with those identified in previously published mapping efforts, but this study's map includes the distribution of surficial deposits and sub-units of the Jezero delta at a higher level of detail than previous studies. This study considers four possible unit correlations to explain the relative age relationships of major units within the map area. Unit correlations include previously published interpretations as well as those that consider more complex interfingering relationships and alternative relative age relationships. The photogeologic map presented here is the foundation for scientific hypothesis development and strategic planning for Perseverance's exploration of Jezero crater.

Organo-mineral associations in chert of the 3.5 Ga Mount Ada Basalt raise questions about the origin of organic matter in Paleoarchean hydrothermally influenced sediments.

Hydrothermal and metamorphic processes could have abiotically produced organo-mineral associations displaying morphological and isotopic characteristics similar to those of fossilized microorganisms in ancient rocks, thereby leaving false-positive evidence for early life in the geological record. Recent studies revealed that geologically-induced alteration processes do not always completely obliterate all molecular information about the original organic precursors of ancient microfossils. Here, we report the molecular, geochemical, and mineralogical composition of organo-mineral associations in a chert sample from the ca. 3.47 billion-year-old (Ga) Mount Ada Basalt, in the Pilbara Craton, Western Australia. Our observations indicate that the molecular characteristics of carbonaceous matter are consistent with hydrothermally altered biological organics, although significantly distinct from that of organic microfossils discovered in a chert sample from the ca. 3.43 Ga Strelley Pool Formation in the same area. Alternatively, the presence of native metal alloys in the chert, previously believed to be unstable in such hydrothermally influenced environments, indicates strongly reducing conditions that were favorable for the abiotic formation of organic matter. Drawing definitive conclusions about the origin of most Paleoarchean organo-mineral associations therefore requires further characterization of a range of natural samples together with experimental simulations to constrain the molecular composition and geological fate of hydrothermally-generated condensed organics.

Alteration of the intaglio surface of lithium disilicate glass-ceramic.

STATEMENT OF PROBLEM: Clinical adjustment of a lithium disilicate glass-ceramic (LDGC) restoration may necessitate its return to the laboratory for additional firing. Evidence of how the intaglio surface should be re-etched after internal adjustment, or after refiring, is lacking. PURPOSE: The purpose of this in vitro study was to investigate the effects of different sequences of etching, refiring, diamond rotary instrument adjustment, airborne-particle abrasion, and re-etching on the microstructure and surface roughness of the intaglio surface of heat-pressed LDGCs. MATERIAL AND METHODS: Heat-pressed LDGC specimens were ground with abrasive paper to produce a uniformly flat surface. The groups (n=3) were subjected to different combinations of etching, refiring, diamond rotary instrument adjustment, airborne-particle abrasion, and re-etching. X-ray diffraction was used to characterize the crystalline phases. Scanning electron microscopy and surface profilometry were used to characterize the microstructure and surface roughness. RESULTS: Qualitative differences were observed in the surface texture of specimens etched for different periods. Excessive etching revealed more of the underlying lithium disilicate crystallites and caused surface pitting for the longest etching period studied. Refiring altered the surface condition but did not completely remove the texture created by the original etching. Diamond rotary instrument adjustment resulted in appreciable surface damage and a higher mean value of measured surface roughness (with or without re-etching) than the other groups. Airborne-particle abrasion caused embedding of particles in the specimen surface, likely corresponding to the abrasion media, although this process resulted in qualitatively less surface damage than diamond rotary instrument adjustment. CONCLUSIONS: Excessive etching, refiring, and adjustment by airborne-particle abrasion or diamond rotary instrument result in qualitative changes in surface condition. Adjustment by diamond rotary instrument results in appreciable surface damage.

Current conditions in medical genetics practice.

PURPOSE: This study of current conditions in medical genetics practice is designed to inform public policy development and present possible solutions for improving access to genetic services. METHODS: Using the American College of Medical Genetics and Genomics Member Directory, membership directories from regional collaborative partners, listservs from national partners, and social media, a 16-question survey was electronically distributed in 2015. RESULTS: The responses of 924 genetics professionals and related providers present a snapshot of current practice and an assessment of workforce needs. More than 92% of the respondents (837/910) are involved in clinical care. Among geneticists, 60% spend more than 51% of their time in clinical care. Geneticists reported an average of 10.2 new patients per week and 7.8 follow-up visits per week. More than 62% of geneticists said that their practices were nearly full; 9.4% said that they were not taking new patients. The survey identified more than 100 geneticists and 200 genetic counselor job vacancies. Fewer than 18% of respondents reported use of telemedicine. CONCLUSION: When compared with previously published workforce studies, these data show that wait times and average new patient caseloads have increased, while the number of geneticists has not.

Microbially influenced formation of Neoarchean ooids.

Ooids are accretionary grains commonly reported from turbulent, shallow-water environments. They have long been associated with microbially dominated ecosystems and often occur in close proximity to, or embedded within, stromatolites, yet have historically been thought to form solely through physicochemical processes. Numerous studies have revealed both constructive and destructive roles for microbes colonizing the surfaces of modern calcitic and aragonitic ooids, but there has been little evidence for the operation of these processes during the Archean and Proterozoic, when both ooids and microbially dominated ecosystems were more widespread. Recently described carbonate ooids from the 2.9 Ga Pongola Supergroup, South Africa, include well-preserved examples composed of diagenetic dolomite interpreted to have formed from a high-Mg-calcite precursor. Spatial distributions of organic matter and elements associated with metabolic activity (N, S, and P) were interpreted as evidence for a biologically induced origin. Here, we describe exceptionally well-preserved ooids composed of calcite, collected from Earth's oldest known carbonate lake system, the ~2.72 Ga Meentheena Member (Tumbiana Formation), Fortescue Group, Western Australia. We used optical microscopy, Raman spectroscopy, XRD, SEM-EDS, LA-ICP-MS, EA-IRMS, and a novel micro-XRF instrument to investigate an oolite shoal deposited between stromatolites that preserve abundant evidence for microbial activity. We report an extremely fine, radial-concentric, calcitic microfabric that is similar to the primary and early diagenetic fabrics of calcitic ooids reported from modern temperate lakes. Early diagenetic silica has trapped isotopically light and thermally mature organic matter. The close association of organic matter with mineral phases and microfabrics related to primary and early diagenetic processes suggest incorporation of organic matter occurred during accretion, likely due to the presence of microbial biofilms. We conclude that the oldest known calcitic ooids were likely formed through processes similar to those that mediate the accretion of ooids in similar environments today, including formation within a microbial biosphere.

Author Correction: Reassessing evidence of life in 3,700-million-year-old rocks of Greenland.

In Extended Data Fig. 1 of this Letter, the map showed the field-work location incorrectly; this figure has been corrected online.

Reassessing evidence of life in 3,700-million-year-old rocks of Greenland.

The Palaeoarchean supracrustal belts in Greenland contain Earth's oldest rocks and are a prime target in the search for the earliest evidence of life on Earth. However, metamorphism has largely obliterated original rock textures and compositions, posing a challenge to the preservation of biological signatures. A recent study of 3,700-million-year-old rocks of the Isua supracrustal belt in Greenland described a rare zone in which low deformation and a closed metamorphic system allowed preservation of primary sedimentary features, including putative conical and domical stromatolites1 (laminated accretionary structures formed by microbially mediated sedimentation). The morphology, layering, mineralogy, chemistry and geological context of the structures were attributed to the formation of microbial mats in a shallow marine environment by 3,700 million years ago, at the start of Earth's rock record. Here we report new research that shows a non-biological, post-depositional origin for the structures. Three-dimensional analysis of the morphology and orientation of the structures within the context of host rock fabrics, combined with texture-specific analyses of major and trace element chemistry, show that the 'stromatolites' are more plausibly interpreted as part of an assemblage of deformation structures formed in carbonate-altered metasediments long after burial. The investigation of the structures of the Isua supracrustal belt serves as a cautionary tale in the search for signs of past life on Mars, highlighting the importance of three-dimensional, integrated analysis of morphology, rock fabrics and geochemistry at appropriate scales.

Challenges and opportunities for effective delivery of clinical genetic services in the U.S. healthcare system.

PURPOSE OF REVIEW: Demand for clinical genetics and genomics services is increasing. As discussed in this study, the clinical genetics and genomics workforce is small. How to meet the demand with a limited workforce requires innovation. RECENT FINDINGS: Background data regarding the current state of clinical genetic services including volume of services and make-up of the clinical genetics workforce are presented. The study then identifies opportunities to increase access to clinical genetic service providers using new models of service and discusses examples of solutions which have been implemented in some practice settings. Creative uses of technology to increase providers' efficiency are highlighted. SUMMARY: Clinical genetics service providers need to rise to the occasion and lead the transformation of clinical genetic service delivery. Many of the examples of solutions described in the study can be implemented by other providers now. Additionally, the described solutions may serve to inspire genetic providers to create their own new solutions, which should then be shared with the provider community.

Building A Regulatory And Payment Framework Flexible Enough To Withstand Technological Progress.

The evolution of digital health is entwined with federal regulation and policy. Whether considering what is or is not a medical device, the reimbursement for digital medical technologies, or physician services under Medicare or Medicaid related to remote patient monitoring or telehealth, the rules and policies governing digital health have not been easy to distinguish. In the face of rapid innovation, it has been difficult to fit these products and services into existing regulations of the Food and Drug Administration and the Centers for Medicare and Medicaid Services, particularly when these frameworks never contemplated what communications technologies can do today. Instead, rules have been misapplied, and in some cases, they have hampered the use of these technologies, depressing the proliferation of associated services. However, regulations have begun to change. We discuss the policy and regulatory changes that have begun to evolve and where they should continue to head.

Automating X-ray Fluorescence Analysis for Rapid Astrobiology Surveys.

UNLABELLED: A new generation of planetary rover instruments, such as PIXL (Planetary Instrument for X-ray Lithochemistry) and SHERLOC (Scanning Habitable Environments with Raman Luminescence for Organics and Chemicals) selected for the Mars 2020 mission rover payload, aim to map mineralogical and elemental composition in situ at microscopic scales. These instruments will produce large spectral cubes with thousands of channels acquired over thousands of spatial locations, a large potential science yield limited mainly by the time required to acquire a measurement after placement. A secondary bottleneck also faces mission planners after downlink; analysts must interpret the complex data products quickly to inform tactical planning for the next command cycle. This study demonstrates operational approaches to overcome these bottlenecks by specialized early-stage science data processing. Onboard, simple real-time systems can perform a basic compositional assessment, recognizing specific features of interest and optimizing sensor integration time to characterize anomalies. On the ground, statistically motivated visualization can make raw uncalibrated data products more interpretable for tactical decision making. Techniques such as manifold dimensionality reduction can help operators comprehend large databases at a glance, identifying trends and anomalies in data. These onboard and ground-side analyses can complement a quantitative interpretation. We evaluate system performance for the case study of PIXL, an X-ray fluorescence spectrometer. Experiments on three representative samples demonstrate improved methods for onboard and ground-side automation and illustrate new astrobiological science capabilities unavailable in previous planetary instruments. KEY WORDS: Dimensionality reduction-Planetary science-Visualization.

Sulfur-cycling fossil bacteria from the 1.8-Ga Duck Creek Formation provide promising evidence of evolution's null hypothesis.

The recent discovery of a deep-water sulfur-cycling microbial biota in the ∼ 2.3-Ga Western Australian Turee Creek Group opened a new window to life's early history. We now report a second such subseafloor-inhabiting community from the Western Australian ∼ 1.8-Ga Duck Creek Formation. Permineralized in cherts formed during and soon after the 2.4- to 2.2-Ga "Great Oxidation Event," these two biotas may evidence an opportunistic response to the mid-Precambrian increase of environmental oxygen that resulted in increased production of metabolically useable sulfate and nitrate. The marked similarity of microbial morphology, habitat, and organization of these fossil communities to their modern counterparts documents exceptionally slow (hypobradytelic) change that, if paralleled by their molecular biology, would evidence extreme evolutionary stasis.