Carbon Fate, Iron Dissolution, and Molecular Characterization of Dissolved Organic Matter in Thawed Yedoma Permafrost under Varying Redox Conditions.

Permafrost soils store ∼50% of terrestrial C, with Yedoma permafrost containing ∼25% of the total C. Permafrost is undergoing degradation due to thawing, with potentially hazardous effects on landscape stability and water resources. Complicating ongoing efforts to project the ultimate fate of deep permafrost C is the poorly constrained role of the redox environment, Fe-minerals, and its redox-active phases, which may modulate organic C-abundance, composition, and reactivity through complexation and catalytic processes. We characterized C fate, Fe fractions, and dissolved organic matter (DOM) isolates from permafrost-thaw under varying redox conditions. Under anoxic incubation conditions, 33% of the initial C was lost as gaseous species within 21 days, while under oxic conditions, 58% of C was lost. Under anoxic incubation, 42% of the total initial C was preserved in a dissolved fraction. Lignin-like compounds dominated permafrost-thaw, followed by lipid- and protein-like compounds. However, under anoxic incubation conditions, there was accumulation of lipid-like compounds and reduction in the nominal oxidation state of C over time, regardless of the compound classes. DOM dynamics may be affected by microbial activity and abiotic processes mediated by Fe-minerals related to selective DOM fractionation and/or its oxidation. Chemodiversity DOM signatures could serve as valuable proxies to track redox conditions with permafrost-thaw.

Right to mental integrity and neurotechnologies: implications of the extended mind thesis.

The possibility of neurotechnological interference with our brain and mind raises questions about the moral rights that would protect against the (mis)use of these technologies. One such moral right that has received recent attention is the right to mental integrity. Though the metaphysical boundaries of the mind are a matter of live debate, most defences of this moral right seem to assume an internalist (brain-based) view of the mind. In this article, we will examine what an extended account of the mind might imply for the right to mental integrity and the protection it provides against neurotechnologies. We argue that, on an extended account of the mind, the scope of the right to mental integrity would expand significantly, implying that neurotechnologies would no longer pose a uniquely serious threat to the right. In addition, some neurotechnologies may even be protected by the right to mental integrity, as the technologies would become part of the mind. We conclude that adopting an extended account of the mind has significant implications for the right to mental integrity in terms of its protective scope and capacity to protect against neurotechnologies, demonstrating that metaphysical assumptions about the mind play an important role in determining the moral protection provided by the right.

Detection of Traumatic Ankle Arthrotomies: Computed Tomography Scan Versus Saline Load Test.

OBJECTIVE: Periarticular wounds present a common diagnostic dilemma for emergency providers and orthopedic surgeons because traumatic arthrotomies (TA) often necessitate different management from superficial soft tissue wounds. Historically, TA have been diagnosed with the saline load test (SLT). Computed tomography (CT) scan has been studied as an alternative to SLT in diagnosing TA in several joints, but there are limited data specifically pertaining to the ankle. This study aimed to compare the ability of a CT scan to identify an ankle TA versus a traditional SLT. The hypothesis was that there would be no significant difference between a CT scan and SLT in diagnosing ankle TA in a cadaveric model. METHODS: This cadaveric study used 10 thawed fresh-frozen cadaveric ankles. A baseline CT scan was performed to ensure no intra-articular air existed before simulated TA. After the baseline CT, a 1 cm TA was created in the anterolateral arthroscopy portal site location. The ankles then underwent a postarthrotomy CT scan to evaluate for the presence of intra-articular air. After the CT scan, a 30 mL SLT was performed using the anteromedial portal site location. RESULTS: After arthrotomy, intra-articular air was visualized in 7 of 10 cadavers in the postarthrotomy CT scan. All the ankles had fluid extravasation during the SLT with <10 mL of saline. The sensitivity of the SLT for TA was 100% versus 70% for the CT scan. CONCLUSIONS: The SLT was more sensitive in diagnosing 1-cm ankle TA than a CT scan in a cadaveric model.

Persistent net release of carbon dioxide and methane from an Alaskan lowland boreal peatland complex.

Permafrost degradation in peatlands is altering vegetation and soil properties and impacting net carbon storage. We studied four adjacent sites in Alaska with varied permafrost regimes, including a black spruce forest on a peat plateau with permafrost, two collapse scar bogs of different ages formed following thermokarst, and a rich fen without permafrost. Measurements included year-round eddy covariance estimates of net carbon dioxide (CO2 ), mid-April to October methane (CH4 ) emissions, and environmental variables. From 2011 to 2022, annual rainfall was above the historical average, snow water equivalent increased, and snow-season duration shortened due to later snow return. Seasonally thawed active layer depths also increased. During this period, all ecosystems acted as slight annual sources of CO2 (13-59 g C m-2 year-1 ) and stronger sources of CH4 (11-14 g CH4 m-2 from ~April to October). The interannual variability of net ecosystem exchange was high, approximately ±100 g C m-2 year-1 , or twice what has been previously reported across other boreal sites. Net CO2 release was positively related to increased summer rainfall and winter snow water equivalent and later snow return. Controls over CH4 emissions were related to increased soil moisture and inundation status. The dominant emitter of carbon was the rich fen, which, in addition to being a source of CO2 , was also the largest CH4 emitter. These results suggest that the future carbon-source strength of boreal lowlands in Interior Alaska may be determined by the area occupied by minerotrophic fens, which are expected to become more abundant as permafrost thaw increases hydrologic connectivity. Since our measurements occur within close proximity of each other (≤1 km2 ), this study also has implications for the spatial scale and data used in benchmarking carbon cycle models and emphasizes the necessity of long-term measurements to identify carbon cycle process changes in a warming climate.

How moral bioenhancement affects perceived praiseworthiness.

Psychological literature indicates that actions performed with the assistance of cognition-enhancing biomedical technologies are often deemed to be less praiseworthy than similar actions performed without such assistance. This study examines (i) whether this result extends to the bioenhancement of moral capacities, and (ii) if so, what explains the effect of moral bioenhancement on perceived praiseworthiness. The findings indicate that actions facilitated by morally bioenhanced individuals are considered less deserving of praise than similar actions facilitated by 'traditional' moral enhancement-for example, moral self-education. This diminished praise does not seem to be driven by an aversion to (moral) bioenhancement per se. Instead, it appears to be primarily attributable to a perceived lack of effort exerted by bioenhanced individuals in the course of their moral enhancement. Our findings advance the philosophical discourse on the foundations of praise in the context of moral bioenhancement by elucidating the empirical basis underlying some assumptions commonly employed to argue for or against the permissibility of moral bioenhancement.

What makes a medical intervention invasive?

The classification of medical interventions as either invasive or non-invasive is commonly regarded to be morally important. On the most commonly endorsed account of invasiveness, a medical intervention is invasive if and only if it involves either breaking the skin ('incision') or inserting an object into the body ('insertion'). Building on recent discussions of the concept of invasiveness, we show that this standard account fails to capture three aspects of existing usage of the concept of invasiveness in relation to medical interventions-namely, (1) usage implying that invasiveness comes in degrees, (2) that the invasiveness of an intervention can depend on the characteristics of the salient alternative interventions, and (3) that medical interventions can be invasive in non-physical ways. We then offer the beginnings of a revised account that, we argue, is able to capture a wider range of existing usage. Central to our account is a distinction between two properties: basic invasiveness and threshold invasiveness We end by assessing what the standard account gets right, and what more needs to be done to complete our schematic account.

Earth to Mars: A Protocol for Characterizing Permafrost in the Context of Climate Change as an Analog for Extraplanetary Exploration.

Abstract Permafrost is important from an exobiology and climate change perspective. It serves as an analog for extraplanetary exploration, and it threatens to emit globally significant amounts of greenhouse gases as it thaws due to climate change. Viable microbes survive in Earth's permafrost, slowly metabolizing and transforming organic matter through geologic time. Ancient permafrost microbial communities represent a crucial resource for gaining novel insights into survival strategies adopted by extremotolerant organisms in extraplanetary analogs. We present a proof-of-concept study on ∼22 Kya permafrost to determine the potential for coupling Raman and fluorescence biosignature detection technology from the NASA Mars Perseverance rover with microbial community characterization in frozen soils, which could be expanded to other Earth and off-Earth locations. Besides the well-known utility for biosignature detection and identification, our results indicate that spectral mapping of permafrost could be used to rapidly characterize organic carbon characteristics. Coupled with microbial community analyses, this method has the potential to enhance our understanding of carbon degradation and emissions in thawing permafrost. Further, spectroscopy can be accomplished in situ to mitigate sample transport challenges and in assessing and prioritizing frozen soils for further investigation. This method has broad-range applicability to understanding microbial communities and their associations with biosignatures and soil carbon and mineralogic characteristics relevant to climate science and astrobiology.

A radiologic determination of the different screw cutting patterns in cut and uncut orthopedic cortical screws using a novel imaging technique.

OBJECTIVE: We hypothesize that cut screws will deform in a manner that increases the core and outer diameters of the screw hole compared to uncut controls, and effects will be more pronounced in titanium screws. MATERIALS AND METHODS: We used biomechanical polyurethane foam blocks to simulate cortical bone. We organized four groups of stainless steel and titanium cut and uncut screws. Blocks were fitted with a jig to ensure perpendicular screw insertion. We imaged the blocks using digital mammography and measured them using PACS software. Power analysis determined a power of 0.95 and an alpha error of 0.05. RESULTS: Highly statistically significant differences in core diameter were found after cutting stainless steel and titanium screws. Cutting stainless steel screws increased core diameter by 0.30 mm (95% CI, 0.16 to 0.45; p < .001). Titanium screws' core diameter increased by 0.45 mm (95% CI, 0.30 to 0.61; p < .001). No significant differences were found in the outer diameters of stainless steel and titanium screws after cutting. CONCLUSION: Titanium and stainless steel screw tracts demonstrated screw core diameter and screw thread pattern deformation after cutting. Titanium screws demonstrated more significant effects.

Permafrost microbial communities and functional genes are structured by latitudinal and soil geochemical gradients.

Permafrost underlies approximately one quarter of Northern Hemisphere terrestrial surfaces and contains 25-50% of the global soil carbon (C) pool. Permafrost soils and the C stocks within are vulnerable to ongoing and future projected climate warming. The biogeography of microbial communities inhabiting permafrost has not been examined beyond a small number of sites focused on local-scale variation. Permafrost is different from other soils. Perennially frozen conditions in permafrost dictate that microbial communities do not turn over quickly, thus possibly providing strong linkages to past environments. Thus, the factors structuring the composition and function of microbial communities may differ from patterns observed in other terrestrial environments. Here, we analyzed 133 permafrost metagenomes from North America, Europe, and Asia. Permafrost biodiversity and taxonomic distribution varied in relation to pH, latitude and soil depth. The distribution of genes differed by latitude, soil depth, age, and pH. Genes that were the most highly variable across all sites were associated with energy metabolism and C-assimilation. Specifically, methanogenesis, fermentation, nitrate reduction, and replenishment of citric acid cycle intermediates. This suggests that adaptations to energy acquisition and substrate availability are among some of the strongest selective pressures shaping permafrost microbial communities. The spatial variation in metabolic potential has primed communities for specific biogeochemical processes as soils thaw due to climate change, which could cause regional- to global- scale variation in C and nitrogen processing and greenhouse gas emissions.

Minding Rights: Mapping Ethical and Legal Foundations of 'Neurorights'.

The rise of neurotechnologies, especially in combination with artificial intelligence (AI)-based methods for brain data analytics, has given rise to concerns around the protection of mental privacy, mental integrity and cognitive liberty - often framed as "neurorights" in ethical, legal, and policy discussions. Several states are now looking at including neurorights into their constitutional legal frameworks, and international institutions and organizations, such as UNESCO and the Council of Europe, are taking an active interest in developing international policy and governance guidelines on this issue. However, in many discussions of neurorights the philosophical assumptions, ethical frames of reference and legal interpretation are either not made explicit or conflict with each other. The aim of this multidisciplinary work is to provide conceptual, ethical, and legal foundations that allow for facilitating a common minimalist conceptual understanding of mental privacy, mental integrity, and cognitive liberty to facilitate scholarly, legal, and policy discussions.

Persistence and Potential Atmospheric Ramifications of Ice-Nucleating Particles Released from Thawing Permafrost.

Permafrost underlies approximately a quarter of the Northern Hemisphere and is changing amidst a warming climate. Thawed permafrost can enter water bodies through top-down thaw, thermokarst erosion, and slumping. Recent work revealed that permafrost contains ice-nucleating particles (INPs) with concentrations comparable to midlatitude topsoil. These INPs may impact the surface energy budget of the Arctic by affecting mixed-phase clouds, if emitted into the atmosphere. In two 3-4-week experiments, we placed 30,000- and 1000-year-old ice-rich silt permafrost in a tank with artificial freshwater and monitored aerosol INP emissions and water INP concentrations as the water's salinity and temperature were varied to mimic aging and transport of thawed material into seawater. We also tracked aerosol and water INP composition through thermal treatments and peroxide digestions and bacterial community composition with DNA sequencing. We found that the older permafrost produced the highest and most stable airborne INP concentrations, with levels comparable to desert dust when normalized to particle surface area. Both samples showed that the transfer of INPs to air persisted during simulated transport to the ocean, demonstrating a potential to influence the Arctic INP budget. This suggests an urgent need for quantifying permafrost INP sources and airborne emission mechanisms in climate models.

Attenuation of Pb and Sb in shooting range soils by Fe amendments.

Lead (Pb) and antimony (Sb) contamination pose a major environmental risk at firing ranges and threaten land sustainability. Methods for the stabilization of metal (loid) contaminants are necessary to prevent off-site migration of metals in surface and ground water or from soil erosion. In the present study, two remediation treatments (ferric chloride/calcium carbonate and nanoscale zero-valent iron (nZVI)) were applied to flow-through soil columns containing four types of soils (sand, sandy loam, loamy sand, and silty loam) to study Pb and Sb behavior. Water runoff was continuously monitored for three months prior to amendment addition and for the following ten months. Soils were characterized before and after reaction. We found Sb was more mobile than Pb in all soil systems and was primarily present in the dissolved fraction whereas Pb was associated with both soil organic matter (SOM) and Fe colloids. Dominant Pb solid phase species were comprised of Pb0, PbO, PbCO3, and Pb sorbed to Fe(III) oxides while Sb was present as fully oxidized Sb(V) in soil and soil solution. The nZVI addition had minimal impact on Pb and Sb immobilization compared to control soil. The FeCl2 and CaCO3 amendment decreased pore water Sb concentrations by >80% for all soil types and >96% reduction in the fine- and coarse-grained soil types (silt loam and sand). Lead was initially mobilized coinciding with a decrease in pH from the hydrolysis of Fe(II) in solution. Additional soil treatments have the potential to be effective for system-wide immobilization with adequate additions of CaCO3 buffer. Though this study focused on bullet fragment weathering as a source of Pb and Sb the results have application to environmental monitoring and remediation efforts at mining or industrial runoff sites.

Arctic methylmercury cycling.

Anthropogenic mercury (Hg) undergoes long-range transport to the Arctic where some of it is transformed into methylmercury (MeHg), potentially leading to high exposure in some Arctic inhabitants and wildlife. The environmental exposure of Hg is determined not just by the amount of Hg entering the Arctic, but also by biogeochemical and ecological processes occurring in the Arctic. These processes affect MeHg uptake in biota by regulating the bioavailability, methylation and demethylation, bioaccumulation and biomagnification of MeHg in Arctic ecosystems. Here, we present a new budget for pools and fluxes of MeHg in the Arctic and review the scientific advances made in the last decade on processes leading to environmental exposure to Hg. Methylation and demethylation are key processes controlling the pool of MeHg available for bioaccumulation. Methylation of Hg occurs in diverse Arctic environments including permafrost, sediments and the ocean water column, and is primarily a process carried out by microorganisms. While microorganisms carrying the hgcAB gene pair (responsible for Hg methylation) have been identified in Arctic soils and thawing permafrost, the formation pathway of MeHg in oxic marine waters remains less clear. Hotspots for methylation of Hg in terrestrial environments include thermokarst wetlands, ponds and lakes. The shallow sub-surface enrichment of MeHg in the Arctic Ocean, in comparison to other marine systems, is a possible explanation for high MeHg concentrations in some Arctic biota. Bioconcentration of aqueous MeHg in bacteria and algae is a critical step in the transfer of Hg to top predators, which may be dampened or enhanced by the presence of organic matter. Variable trophic position has an important influence on MeHg concentrations among populations of top predator species such as ringed seal and polar bears distributed across the circumpolar Arctic. These scientific advances highlight key processes that affect the fate of anthropogenic Hg deposited to Arctic environments.

Carbon and nitrogen cycling dynamics following permafrost thaw in the Northwest Territories, Canada.

Rapid climate warming across northern high latitudes is leading to permafrost thaw and ecosystem carbon release while simultaneously impacting other biogeochemical cycles including nitrogen. We used a two-year laboratory incubation study to quantify concomitant changes in carbon and nitrogen pool quantity and quality as drivers of potential CO2 production in thawed permafrost soils from eight soil cores collected across the southern Northwest Territories (NWT), Canada. These data were contextualized via in situ annual thaw depth measurements from 2015 to 2019 at 40 study sites that varied in burn history. We found with increasing time since experimental thaw the dissolved carbon and nitrogen pool quality significantly declined, indicating sustained microbial processing and selective immobilization across both pools. Piecewise structural equation modeling revealed CO2 trends were predominantly predicted by initial soil carbon content with minimal influence of dissolved phase carbon. Using these results, we provide a first-order estimate of potential near-surface permafrost soil losses of up to 80 g C m-2 over one year in southern NWT, exceeding regional historic mean primary productivity rates in some areas. Taken together, this research provides mechanistic knowledge needed to further constrain the permafrost­carbon feedback and parameterize Earth system models, while building on empirical evidence that permafrost soils are at high risk of becoming weaker carbon sinks or even significant carbon sources under a changing climate.

The Expressivist Objection to Nonconsensual Neurocorrectives.

Neurointerventions-interventions that physically or chemically modulate brain states-are sometimes imposed on criminal offenders for the purposes of diminishing the risk that they will recidivate, or, more generally, of facilitating their rehabilitation. One objection to the nonconsensual implementation of such interventions holds that this expresses a disrespectful message, and is thus impermissible. In this paper, we respond to this objection, focusing on the most developed version of it-that presented by Elizabeth Shaw. We consider a variety of messages that might be expressed by nonconsensual neurointerventions. Depending on the message, we argue either that such interventions do not invariably express this message, that expressing this message is not invariably disrespectful, or that the appeal to disrespect is redundant.

What is Criminal Rehabilitation?

It is often said that the institutions of criminal justice ought or-perhaps more often-ought not to rehabilitate criminal offenders. But the term 'criminal rehabilitation' is often used without being explicitly defined, and in ways that are consistent with widely divergent conceptions. In this paper, we present a taxonomy that distinguishes, and explains the relationships between, different conceptions of criminal rehabilitation. Our taxonomy distinguishes conceptions of criminal rehabilitation on the basis of (i) the aims or ends of the putatively rehabilitative measure, and (ii) the means that may be used to achieve the intended end. We also explore some of the implications of each conception, some of the payoffs of a taxonomy of the kind we offer, and some areas for future work.