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.

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.

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.

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.

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.

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.

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.

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.

Per- and Polyfluoroalkyl Substances (PFAS) in Street Sweepings.

One hundred and seventeen street sweeping samples were collected and analyzed for per- and polyfluoroalkyl substances (PFAS). Fifty-six samples were collected in one city (Gainesville, Florida) allowing for an in-depth city-wide characterization. Street sweepings from five other urban areas, (Orlando, n = 15; Key West, n = 15; Pensacola, n = 12; Tampa, n = 13; and Daytona Beach, n = 6) were analyzed to provide a city-to-city comparison of PFAS. Within our analytical workflow, 37 PFAS were quantified across all samples, while the maximum number of PFAS quantified at one site was 26. Of those PFAS quantified in Gainesville, 60% were perfluoroalkyl acids (PFAAs) and 33% were precursors to PFAA. Among the PFAAs, short-chain perfluoroalkyl carboxylic acids (PFCAs) were the dominant class representing 26% of the total PFAS by concentration. In the comparison across different urban cities, the dominant compound by concentration and frequency of detection varied; however, perfluorooctanoic acid (PFOA) and linear perfluorooctanesulfonic acid (PFOSlin) were the two PFAS that were detected the most frequently. This study documents the first-time detection of hexadecafluorosebacic acid and perfluoro-3,6,9-trioxaundecane-1,11-dioic acid within environmental samples.

Widespread global peatland establishment and persistence over the last 130,000 y.

Glacial-interglacial variations in CO2 and methane in polar ice cores have been attributed, in part, to changes in global wetland extent, but the wetland distribution before the Last Glacial Maximum (LGM, 21 ka to 18 ka) remains virtually unknown. We present a study of global peatland extent and carbon (C) stocks through the last glacial cycle (130 ka to present) using a newly compiled database of 1,063 detailed stratigraphic records of peat deposits buried by mineral sediments, as well as a global peatland model. Quantitative agreement between modeling and observations shows extensive peat accumulation before the LGM in northern latitudes (>40°N), particularly during warmer periods including the last interglacial (130 ka to 116 ka, MIS 5e) and the interstadial (57 ka to 29 ka, MIS 3). During cooling periods of glacial advance and permafrost formation, the burial of northern peatlands by glaciers and mineral sediments decreased active peatland extent, thickness, and modeled C stocks by 70 to 90% from warmer times. Tropical peatland extent and C stocks show little temporal variation throughout the study period. While the increased burial of northern peats was correlated with cooling periods, the burial of tropical peat was predominately driven by changes in sea level and regional hydrology. Peat burial by mineral sediments represents a mechanism for long-term terrestrial C storage in the Earth system. These results show that northern peatlands accumulate significant C stocks during warmer times, indicating their potential for C sequestration during the warming Anthropocene.

The Mere Substitution Defence of Nudging Works for Neurointerventions Too.

Nudges are often defended on the basis that they merely substitute existing influences on choice with other influences that are similar in kind; they introduce no new kind of influence into the choice situation. I motivate the view that, if this defence succeeds in establishing the moral innocuousness of typical nudges, it also establishes the moral innocuousness of an intuitively wrongful neurochemical intervention. I then consider two attempts to rebut this view and argue that both fail. I end by spelling out four stances that the proponent of the defence might adopt in response to my argument.

Do Mid-term Outcomes of Lateral Ankle Stabilization Procedures Differ Between Military and Civilian Populations?

BACKGROUND: Ankle instability is common and previous studies have documented greater than 85% good-to-excellent outcomes based upon both patient-reported outcome measures and subjective evaluation of ability to return to previous activity levels after lateral ankle stabilization in the civilian population. However, patient-reported outcomes and performance may differ in the military population. The military oftentimes requires servicemembers to navigate uneven terrain and ladderwells, which can stress ankles differently than in their civilian counterparts. There has been limited evidence regarding patient outcomes after lateral ankle stabilization within a military population and its elucidation is important in optimizing outcomes for our servicemembers. Furthermore, the potential benefit of fibular periosteum augmentation with lateral ankle stabilization procedures in a military population has not been described. The results of using this extra tissue to reinforce the repair are important in determining whether its routine incorporation is indicated in the military. QUESTIONS/PURPOSES: In an active-duty military population, we asked: (1) What proportion of patients who underwent lateral ankle stabilization using anatomic repair techniques with or without fibular periosteum augmentation achieved good-to-excellent outcomes based on the Foot and Ankle Disability Index (FADI) score at a minimum follow-up interval of 2 years? (2) Was the proportion of patients who achieved a good-to-excellent FADI score higher among those treated with fibular periosteum augmentation than those treated without? (3) Did the likelihood of achieving a good-to-excellent outcome after lateral ankle stabilization vary based on whether the procedure was performed by a fellowship-trained sports or foot and ankle orthopaedic surgeon versus a podiatrist? METHODS: Between 2007 and 2017, 15 surgeons (six orthopaedic surgeons and nine podiatrists) performed 502 lateral ankle stabilizations. We excluded 4% (18 of 502) of patients because they were not active-duty at the time of surgery, and we excluded 12% (56 of 502) of lateral ankle stabilizations because they were performed as part of other potentially confounding foot or ankle procedures. We considered 60% (303 of 502) as lost to follow-up because the patients could not be contacted at least 2 years after surgery, they declined to participate, or they did not fully answer the questionnaires. This left 125 patients for analysis. Of those, 79% (99 of 125) had a procedure with fibular periosteum augmentation and 21% (26 of 125) had a procedure without augmentation. During the study period, five fellowship-trained orthopaedic foot and ankle surgeons and two podiatrists always used fibular periosteum augmentation. Orthopaedic surgeons performed 75% (94 of 125) of the procedures, and the other 25% (31 of 125) were performed by podiatrists. Whether a servicemember was treated by one specialty or the other was simply based upon whom they were referred to for care. Orthopaedic surgeons tended to perform procedures with augmentation (five with versus one without) and podiatrists tended to perform procedures without augmentation (two with versus seven without). To help account for this confounding factor, we performed separate analyses for procedures performed with versus without augmentation in addition to procedures performed by orthopaedic surgeons versus podiatrists. We retrospectively contacted each patient to obtain their self-reported overall result, FADI outcome score, and postoperative military capabilities. The minimum follow-up duration was 2 years; overall mean follow-up duration was 7 years. The fibular periosteum augmentation group mean follow-up was 7 ± 4 years and without augmentation was 6 ± 3 years. The orthopaedic surgeons group mean follow-up was 7 ± 3 years and the podiatrists group was 7 ± 3 years. We obtained postoperative FADI scores via phone interview along with data regarding the patients' postoperative military capabilities, but did not have preoperative FADI scores. RESULTS: Pooling both surgical treatments, 67% (84 of 125) of the patients reported good-to-excellent results and 33% (41 of 125) reported very poor-to-fair results. We found no difference in the proportion of patients treated with fibular periosteal augmentation who achieved a good or excellent score on the FADI than was observed among the patients treated without periosteal augmentation (68% [67 of 99] versus 65% [17 of 26]; odds ratio 1 [95% CI 0 to 2]; p = 0.81). The proportion of patients who achieved a good or excellent score on the FADI did not differ depending on whether the procedure was performed by an orthopaedic surgeon or a podiatric surgeon (66% [62 of 94] versus 71% [22 of 31]; OR 1 [95% CI 1 to 2]; p = 0.66). CONCLUSION: The patient-reported outcome scores after lateral ankle stabilization in our study of military servicemembers at a minimum of 2 years and a mean of 7 years were far lower than have been reported in studies on civilians. Indeed, our findings may represent a best-case scenario because more patients were lost to follow-up than were accounted for, and in general, surgical results among missing patients are poorer than among those who return for follow-up. Variability in the addition of fibular periosteum augmentation and whether an orthopaedic surgeon or podiatrist performed the procedure did not account for these findings. With one third of patients reporting very-poor-to-fair results after these reconstructions, and many patients lost to follow-up, we recommend surgeons counsel their servicemember patients accordingly before surgery. Specifically, that there is a one third chance they will need permanent restrictions or have to leave the military postoperatively; analogously, we believe that our findings may apply to similarly active patients outside the military, and we question whether these procedures may not be serving such patients as well as previously believed. LEVEL OF EVIDENCE: Level III, therapeutic study.

Healthcare, Responsibility and Golden Opportunities.

When it comes to determining how healthcare resources should be allocated, there are many factors that could-and perhaps should-be taken into account. One such factor is a patient's responsibility for his or her illness, or for the behavior that caused it. Policies that take responsibility for the unhealthy lifestyle or its outcomes into account-responsibility-sensitive policies-have faced a series of criticisms. One holds that agents often fail to meet either the control or epistemic conditions on responsibility with regard to their unhealthy lifestyles or their outcomes. Another holds that even if patients sometimes are responsible for these items, we cannot know whether a particular patient is responsible for them. In this article, we propose a type of responsibility-sensitive policy that may be able to surmount these difficulties. Under this type of policy, patients are empowered to change to a healthier lifestyle by being given what we call a 'Golden Opportunity' to change. Such a policy would not only avoid concerns about patients' fulfilment of conditions on responsibility for their lifestyles, it would also allow healthcare authorities to be justified in believing that a patient who does not change her lifestyle is responsible for the unhealthy lifestyle. We conclude with a discussion of avenues for further work, and place this policy in the broader context of the debate on responsibility for health.

Closed-Loop Brain Devices in Offender Rehabilitation: Autonomy, Human Rights, and Accountability.

The current debate on closed-loop brain devices (CBDs) mainly focuses on their use in a medical context; possible criminal justice applications have only received incidental scholarly attention. Unlike in medicine, in criminal justice, CBDs might be offered on behalf of the State and for the purpose of protecting security, rather than realizing healthcare aims. It would be possible to deploy CBDs in the rehabilitation of convicted offenders, similarly to the much-debated possibility of employing other brain interventions in this context. Although such use of CBDs could in principle be consensual, there are significant differences between the choice faced by a criminal offender offered a CBD in the context of criminal justice, and that faced by a patient offered a CBD in an ordinary healthcare context. Employment of CBDs in criminal justice thus raises ethical and legal intricacies not raised by healthcare applications. This paper examines some of these issues under three heads: autonomy, human rights, and accountability.

Selective Adsorption of Pb(II) on an Annealed Hematite (1102) Surface: Evidence from Crystal Truncation Rod X-ray Diffraction and Density Functional Theory.

The Pb(II)-binding mechanism on an annealed hematite (1102) surface was studied using crystal truncation rod (CTR) X-ray diffraction coupled with density functional theory (DFT) calculations. The best fit CTR model suggested that Pb(II) sorbed selectively to one type of edge-sharing surface site (ES2) over two other potential surface sites. From the best fit model structure, it was found that the Pb surface complex species forms a trigonal pyramid geometry. The base consists of three oxygen groups, two of which are associated with the substrate surface (IO and IIIO) and one that is a distal O extending toward solution. The trigonal pyramid geometry is slightly distorted with Pb-O bond lengths ranging from 2.21 to 2.31 Å and O-Pb-O bond angles ranging from 72° to 75°. Under this structural distortion, the nearest distance between Pb and Fe is found to be 3.39(1) Å. Consistent with the CTR results, DFT calculations indicate the Pb binding energy at the ES2 site is at least 0.16 eV more favorable than that at the other two potential binding sites considered. Using bond-valence rules we propose a stoichiometry of Pb(II) binding on the hematite (1102) surface which indicates proton release through the deprotonation of all oxygen groups bonding to Pb.

Spatially Resolved Organomineral Interactions across a Permafrost Chronosequence.

Permafrost contains a large (1700 Pg C) terrestrial pool of organic matter (OM) that is susceptible to degradation as global temperatures increase. Of particular importance is syngenetic Yedoma permafrost containing high OM content. Reactive iron phases promote stabilizing interactions between OM and soil minerals and this stabilization may be of increasing importance in permafrost as the thawed surface region ("active layer") deepens. However, there is limited understanding of Fe and other soil mineral phase associations with OM carbon (C) moieties in permafrost soils. To elucidate the elemental associations involved in organomineral complexation within permafrost systems, soil cores spanning a Pleistocene permafrost chronosequence (19,000, 27,000, and 36,000 years old) were collected from an underground tunnel near Fairbanks, Alaska. Subsamples were analyzed via scanning transmission X-ray microscopy-near edge X-ray absorption fine structure spectroscopy at the nano- to microscale. Amino acid-rich moieties decreased in abundance across the chronosequence. Strong correlations between C and Fe with discrete Fe(III) or Fe(II) regions selectively associated with specific OM moieties were observed. Additionally, Ca coassociated with C through potential cation bridging mechanisms. Results indicate Fe(III), Fe(II), and mixed valence phases associated with OM throughout diverse permafrost environments, suggesting that organomineral complexation is crucial to predict C stability as permafrost systems warm.

Convective forcing of mercury and ozone in the Arctic boundary layer induced by leads in sea ice.

The ongoing regime shift of Arctic sea ice from perennial to seasonal ice is associated with more dynamic patterns of opening and closing sea-ice leads (large transient channels of open water in the ice), which may affect atmospheric and biogeochemical cycles in the Arctic. Mercury and ozone are rapidly removed from the atmospheric boundary layer during depletion events in the Arctic, caused by destruction of ozone along with oxidation of gaseous elemental mercury (Hg(0)) to oxidized mercury (Hg(II)) in the atmosphere and its subsequent deposition to snow and ice. Ozone depletion events can change the oxidative capacity of the air by affecting atmospheric hydroxyl radical chemistry, whereas atmospheric mercury depletion events can increase the deposition of mercury to the Arctic, some of which can enter ecosystems during snowmelt. Here we present near-surface measurements of atmospheric mercury and ozone from two Arctic field campaigns near Barrow, Alaska. We find that coastal depletion events are directly linked to sea-ice dynamics. A consolidated ice cover facilitates the depletion of Hg(0) and ozone, but these immediately recover to near-background concentrations in the upwind presence of open sea-ice leads. We attribute the rapid recoveries of Hg(0) and ozone to lead-initiated shallow convection in the stable Arctic boundary layer, which mixes Hg(0) and ozone from undepleted air masses aloft. This convective forcing provides additional Hg(0) to the surface layer at a time of active depletion chemistry, where it is subject to renewed oxidation. Future work will need to establish the degree to which large-scale changes in sea-ice dynamics across the Arctic alter ozone chemistry and mercury deposition in fragile Arctic ecosystems.

Compulsory medical intervention versus external constraint in pandemic control.

Would compulsory treatment or vaccination for COVID-19 be justified? In England, there would be significant legal barriers to it. However, we offer a conditional ethical argument in favour of allowing compulsory treatment and vaccination, drawing on an ethical comparison with external constraints-such as quarantine, isolation and 'lockdown'-that have already been authorised to control the pandemic in this jurisdiction. We argue that, if the permissive English approach to external constraints for COVID-19 has been justified, then there is a case for a similarly permissive approach to compulsory medical interventions.

Metal accumulation capacity in indigenous Alaska vegetation growing on military training lands.

Permafrost thawing could increase soil contaminant mobilization in the environment. Our objective was to quantify metal accumulation capacities for plant species and functional groups common to Alaskan military training ranges where elevated soil metal concentrations were likely to occur. Plant species across multiple military training range sites were collected. Metal content in shoots and roots was compared to soil metal concentrations to calculate bioconcentration and translocation factors. On average, grasses accumulated greater concentrations of Cr, Cu, Ni, Pb, Sb, and Zn relative to forbs or shrubs, and bioconcentrated greater concentrations of Ni and Pb. Shrubs bioconcentrated greater concentrations of Sb. Translocation to shoots was greatest among the forbs. Three native plants were identified as candidate species for use in metal phytostabilization applications. Elymus macrourus, a grass, bioconcentrated substantial concentrations of Cu, Pb, and Zn in roots with low translocation to shoots. Elaeagnus commutata, a shrub, bioconcentrated the greatest amounts of Sb, Ni, and Cr, with a low translocation factor. Solidago decumbens bioconcentrated the greatest amount of Sb among the forbs and translocated the least amount of metals. A combination of forb, shrub, and grass will likely enhance phytostabilization of heavy metals in interior Alaska soils through increased functional group diversity.

Commentary: Responsibility-Sensitive Healthcare Funding: Three Responses to Clavien and Hurst's Critique.

Christine Clavien and Samia Hurst1 (henceforth C-H) make at least three valuable contributions to the literature on responsibility and healthcare. They offer an admirably clear and workable set of criteria for determining a patient's degree of responsibility for her health condition; they deploy those criteria to cast doubt on the view that patients with lifestyle-related conditions are typically significantly responsible for their conditions; and they outline several practical difficulties that would be raised by any attempt to introduce responsibility-sensitive healthcare funding. I am sympathetic to the general thrust of their argument, share-at least tentatively-their policy conclusions, and was persuaded by much of the detail of their argument. However, I do have three critical comments.