Author Correction: Crowther et al. reply.

In this Brief Communications Arising Reply, the affiliation for author P. H. Templer was incorrectly listed as 'Department of Ecology & Evolutionary Biology, University of California Irvine, Irvine, California 92697, USA' instead of 'Department of Biology, Boston University, Boston, Massachusetts 02215, USA'. This has been corrected online.

Quantifying global soil carbon losses in response to warming.

The majority of the Earth's terrestrial carbon is stored in the soil. If anthropogenic warming stimulates the loss of this carbon to the atmosphere, it could drive further planetary warming. Despite evidence that warming enhances carbon fluxes to and from the soil, the net global balance between these responses remains uncertain. Here we present a comprehensive analysis of warming-induced changes in soil carbon stocks by assembling data from 49 field experiments located across North America, Europe and Asia. We find that the effects of warming are contingent on the size of the initial soil carbon stock, with considerable losses occurring in high-latitude areas. By extrapolating this empirical relationship to the global scale, we provide estimates of soil carbon sensitivity to warming that may help to constrain Earth system model projections. Our empirical relationship suggests that global soil carbon stocks in the upper soil horizons will fall by 30 ± 30 petagrams of carbon to 203 ± 161 petagrams of carbon under one degree of warming, depending on the rate at which the effects of warming are realized. Under the conservative assumption that the response of soil carbon to warming occurs within a year, a business-as-usual climate scenario would drive the loss of 55 ± 50 petagrams of carbon from the upper soil horizons by 2050. This value is around 12-17 per cent of the expected anthropogenic emissions over this period. Despite the considerable uncertainty in our estimates, the direction of the global soil carbon response is consistent across all scenarios. This provides strong empirical support for the idea that rising temperatures will stimulate the net loss of soil carbon to the atmosphere, driving a positive land carbon-climate feedback that could accelerate climate change.

A biomechanical comparison of steel screws versus PLLA and magnesium screws for the Latarjet procedure.

INTRODUCTION: The fixation of the coracoid process onto the glenoid is an important step of the Latarjet procedure, and implant-associated complications are a relevant and severe problem. This study compares the fixation strength and failure mode of two biodegradable materials with stainless-steel screws. METHODS: 24 Fresh-frozen cadaveric scapulae were divided into three groups of equal size and received a coracoid transfer. Cadavers were matched according to their bone mineral density (BMD). In group 1, small-fragment screws made of stainless steel were used. In the second group, magnesium screws were used, and in the third group, screws consisted of polylactic acid (PLLA). A continuously increasing sinusoidal cyclic compression force was applied until failure occurred, which was defined as graft displacement relative to its initial position of more than 5 mm. RESULTS: At 5-mm displacement, the axial force values showed a mean of 374 ± 92 N (range 219-479 N) in group 1 (steel). The force values in group 2 (magnesium) had a mean of 299 ± 57 N (range 190-357 N). In group 3 (PLLA), failure occurred at 231 ± 83 N (range 109-355 N). The difference between group 1 (steel) and group 2 (magnesium) was not statistically significant (P = 0.212), while the difference between group 1 (steel) and group 3 (PLLA) was significant (P = 0.005). CONCLUSION: Stainless-Steel screws showed the highest stability. However, all three screw types showed axial force values of more than 200 N. Stainless steel screws and PLLA screws showed screw cut-out as the most common failure mode, while magnesium screws showed screw breakage in the majority of cases. EVIDENCE: Controlled laboratory study.

Using non-invasive neuroimaging to enhance the care, well-being and experimental outcomes of laboratory non-human primates (monkeys).

Over the past 10-20 years, neuroscience witnessed an explosion in the use of non-invasive imaging methods, particularly magnetic resonance imaging (MRI), to study brain structure and function. Simultaneously, with access to MRI in many research institutions, MRI has become an indispensable tool for researchers and veterinarians to guide improvements in surgical procedures and implants and thus, experimental as well as clinical outcomes, given that access to MRI also allows for improved diagnosis and monitoring for brain disease. As part of the PRIMEatE Data Exchange, we gathered expert scientists, veterinarians, and clinicians who treat humans, to provide an overview of the use of non-invasive imaging tools, primarily MRI, to enhance experimental and welfare outcomes for laboratory non-human primates engaged in neuroscientific experiments. We aimed to provide guidance for other researchers, scientists and veterinarians in the use of this powerful imaging technology as well as to foster a larger conversation and community of scientists and veterinarians with a shared goal of improving the well-being and experimental outcomes for laboratory animals.

Pairing automated mark-recapture and social network models to explore the effects of landscape configuration on hummingbird foraging patterns.

Landscape changes can alter pollinator movement and foraging patterns which can in turn influence the demographic processes of plant populations. We leveraged social network models and four fixed arrays of five hummingbird feeders equipped with radio frequency identification (RFID) data loggers to study rufous hummingbird (Selasphorus rufus) foraging patterns in a heterogeneous landscape. Using a space-for-time approach, we asked whether forest encroachment on alpine meadows could restrict hummingbird foraging movements and impede resource discovery. We fit social network models to data on 2221 movements between feeders made by 29 hummingbirds. Movements were made primarily by females, likely due to male territoriality and early migration dates. Distance was the driving factor in determining the rate of movements among feeders. The posterior mean effects of forest landscape variables (local canopy cover and intervening forest cover) were negative, but with considerable uncertainty. Finally, we found strong reciprocity in hummingbird movements, indicative of frequent out and back movements between resources. Together, these findings suggest that reciprocal movements by female hummingbirds could help maintain bidirectional gene flow among nearby subpopulations of ornithophilous plants; however, if the distance among meadows increases with further forest encroachment, this may limit foraging among progressively isolated meadows.

Linking Genes to Traits in Fungi.

Fungi are mediators of the nitrogen and carbon cycles in terrestrial ecosystems. Examining how nitrogen uptake and organic matter decomposition potential differs in fungi can provide insight into the underlying mechanisms driving fungal ecological processes and ecosystem functioning. In this study, we assessed the frequency of genes encoding for specific enzymes that facilitate nitrogen uptake and organic matter decomposition in 879 fungal genomes with fungal taxa grouped into trait-based categories. Our linked gene-trait data approach revealed that gene frequencies vary across and within trait-based groups and that trait-based categories differ in trait space. We present two examples of how this linked gene-trait approach can be used to address ecological questions. First, we show that this type of approach can help us better understand, and potentially predict, how fungi will respond to environmental stress. Specifically, we found that trait-based categories with high nitrogen uptake gene frequency increased in relative abundance when exposed to high soil nitrogen enrichment. Second, by comparing frequencies of nitrogen uptake and organic matter decomposition genes, we found that most ectomycorrhizal fungi in our dataset have similar gene frequencies to brown rot fungi. This demonstrates that gene-trait data approaches can shed light on potential evolutionary trajectories of life history traits in fungi. We present a framework for exploring nitrogen uptake and organic matter decomposition gene frequencies in fungal trait-based groups and provide two concise examples on how to use our framework to address ecological questions from a mechanistic perspective.

Plant invasion impacts on fungal community structure and function depend on soil warming and nitrogen enrichment.

The impacts of invasive species on biodiversity may be mitigated or exacerbated by abiotic environmental changes. Invasive plants can restructure soil fungal communities with important implications for native biodiversity and nutrient cycling, yet fungal responses to invasion may depend on numerous anthropogenic stressors. In this study, we experimentally invaded a long-term soil warming and simulated nitrogen deposition experiment with the widespread invasive plant Alliaria petiolata (garlic mustard) and tested the responses of soil fungal communities to invasion, abiotic factors, and their interaction. We focused on the phytotoxic garlic mustard because it suppresses native mycorrhizae across forests of North America. We found that invasion in combination with warming, but not under ambient conditions or elevated nitrogen, significantly reduced soil fungal biomass and ectomycorrhizal relative abundances and increased relative abundances of general soil saprotrophs and fungal genes encoding for hydrolytic enzymes. These results suggest that warming potentially exacerbates fungal responses to plant invasion. Soils collected from uninvaded and invaded plots across eight forests spanning a 4 °C temperature gradient further demonstrated that the magnitude of fungal responses to invasion was positively correlated with mean annual temperature. Our study is one of the first empirical tests to show that the impacts of invasion on fungal communities depends on additional anthropogenic pressures and were greater in concert with warming than under elevated nitrogen or ambient conditions.

A close-pair binary in a distant triple supermassive black hole system.

Galaxies are believed to evolve through merging, which should lead to some hosting multiple supermassive black holes. There are four known triple black hole systems, with the closest black hole pair being 2.4 kiloparsecs apart (the third component in this system is at 3 kiloparsecs), which is far from the gravitational sphere of influence (about 100 parsecs for a black hole with mass one billion times that of the Sun). Previous searches for compact black hole systems concluded that they were rare, with the tightest binary system having a separation of 7 parsecs (ref. 10). Here we report observations of a triple black hole system at redshift z = 0.39, with the closest pair separated by about 140 parsecs and significantly more distant from Earth than any other known binary of comparable orbital separation. The effect of the tight pair is to introduce a rotationally symmetric helical modulation on the structure of the large-scale radio jets, which provides a useful way to search for other tight pairs without needing extremely high resolution observations. As we found this tight pair after searching only six galaxies, we conclude that tight pairs are more common than hitherto believed, which is an important observational constraint for low-frequency gravitational wave experiments.

In situ biodistribution and residency of a topical anti-inflammatory using fluorescence lifetime imaging microscopy.

BACKGROUND: GSK2894512 is a topically delivered investigational drug being developed for treatment of atopic dermatitis and psoriasis. OBJECTIVES: To investigate, in a phase I clinical trial, the spatial biodistribution and residency of GSK2894512 within the epidermis and dermis of healthy human participants noninvasively using fluorescence lifetime imaging microscopy (FLIM). METHODS: Two topical drug formulations containing GSK2894512 1% were applied to the right and left forearms of six participants for seven consecutive days, followed by seven days of observation for residency. FLIM images were obtained daily throughout the study, approximately every 24 h. During the treatment phase of the study, images were collected from each participant pretreatment, reflecting the residual dose from the previous day. Three punch biopsies from each participant of one formulation was obtained from the treated region during the post-treatment follow-up period between days 8 and 14 for comparison with FLIM results. RESULTS: Cellular and subcellular features associated with different epidermal and dermal layers were visualized noninvasively, down to a depth of 200 µm. Results yielded three-dimensional maps of GSK2894512 spatial distribution and residency over time. This fluorescence data provided a marker that was used as a monitor for day-to-day variance of drug presence and residency postapplication. CONCLUSIONS: The results suggest FLIM could be a viable alternative to skin biopsies without the usual patient discomfort and limitations, thereby enabling the direct measurement of skin distribution through longitudinal monitoring. These results are the first step in establishing the unique capabilities that multiphoton imaging could provide to patients through noninvasive drug detection.

The genetic basis for most patients with pustular skin disease remains elusive.

BACKGROUND: Rare variants in the genes IL36RN, CARD14 and AP1S3 have been identified to cause or contribute to pustular skin diseases, primarily generalized pustular psoriasis (GPP). OBJECTIVES: To better understand the disease relevance of these genes, we screened our cohorts of patients with pustular skin diseases [primarily GPP and palmoplantar pustular psoriasis (PPP)] for coding changes in these three genes. Carriers of single heterozygous IL36RN mutations were screened for a second mutation in IL36RN. METHODS: Coding exons of IL36RN, CARD14 and AP1S3 were sequenced in 67 patients - 61 with GPP, two with acute generalized exanthematous pustulosis and four with acrodermatitis continua of Hallopeau. We screened IL36RN and AP1S3 for intragenic copy-number variants and 258 patients with PPP for coding changes in AP1S3. Eleven heterozygous IL36RN mutations carriers were analysed for a second noncoding IL36RN mutation. Genotype-phenotype correlations in carriers/noncarriers of IL36RN mutations were assessed within the GPP cohort. RESULTS: The majority of patients (GPP, 64%) did not carry rare variants in any of the three genes. Biallelic and monoallelic IL36RN mutations were identified in 15 and five patients with GPP, respectively. Noncoding rare IL36RN variants were not identified in heterozygous carriers. The only significant genotype-phenotype correlation observed for IL36RN mutation carriers was early age at disease onset. Additional rare CARD14 or AP1S3 variants were identified in 15% of IL36RN mutation carriers. CONCLUSIONS: The identification of IL36RN mutation carriers harbouring additional rare variants in CARD14 or AP1S3 indicates a more complex mode of inheritance of pustular psoriasis. Our results suggest that, in heterozygous IL36RN mutation carriers, there are additional disease-causing genetic factors outside IL36RN.

Direct bone morphogenetic protein 2 and Indian hedgehog gene transfer for articular cartilage repair using bone marrow coagulates.

OBJECTIVE: Bone morphogenetic protein 2 (BMP-2, encoded by BMP2) and Indian hedgehog protein (IHH, encoded by IHH) are well known regulators of chondrogenesis and chondrogenic hypertrophy. Despite being a potent chondrogenic factor BMP-2 was observed to induce chondrocyte hypertrophy in osteoarthritis (OA), growth plate cartilage and adult mesenchymal stem cells (MSCs). IHH might induce chondrogenic differentiation through different intracellular signalling pathways without inducing subsequent chondrocyte hypertrophy. The primary objective of this study is to test the efficacy of direct BMP2 and IHH gene delivery via bone marrow coagulates to influence histological repair cartilage quality in vivo. METHOD: Vector-laden autologous bone marrow coagulates with 10(11) adenoviral vector particles encoding BMP2, IHH or the Green fluorescent protein (GFP) were delivered to 3.2 mm osteochondral defects in the trochlea of rabbit knees. After 13 weeks the histological repair cartilage quality was assessed using the ICRS II scoring system and the type II collagen positive area. RESULTS: IHH treatment resulted in superior histological repair cartilage quality than GFP controls in all of the assessed parameters (with P < 0.05 in five of 14 assessed parameters). Results of BMP2 treatment varied substantially, including severe intralesional bone formation in two of six joints after 13 weeks. CONCLUSION: IHH gene transfer is effective to improve repair cartilage quality in vivo, whereas BMP2 treatment, carried the risk intralesional bone formation. Therefore IHH protein can be considered as an attractive alternative candidate growth factor for further preclinical research and development towards improved treatments for articular cartilage defects.

Simulated glass-forming polymer melts: dynamic scattering functions, chain length effects, and mode-coupling theory analysis.

We present molecular-dynamics simulations for a fully flexible model of polymer melts with different chain length N ranging from short oligomers (N = 4) to values near the entanglement length (N = 64). For these systems we explore the structural relaxation of the supercooled melt near the critical temperature T c of mode-coupling theory (MCT). Coherent and incoherent scattering functions are analyzed in terms of the idealized MCT. For temperatures T > T c we provide evidence for the space-time factorization property of the ß relaxation and for the time-temperature superposition principle (TTSP) of the α relaxation, and we also discuss deviations from these predictions for T ≈ T c. For T larger than the smallest temperature where the TTSP holds we perform a quantitative analysis of the dynamics with the asymptotic MCT predictions for the late ß regime. Within MCT a key quantity, in addition to T c, is the exponent parameter λ. For the fully flexible polymer models studied we find that λ is independent of N and has a value (λ = 0.735 ) typical of simple glass-forming liquids. On the other hand, the critical temperature increases with chain length toward an asymptotic value T c (∞) . This increase can be described by T c (∞) - T c(N) ∼ 1/N and may be interpreted in terms of the N dependence of the monomer density ρ, if we assume that the MCT glass transition is ruled by a soft-sphere-like constant coupling parameter Γ c = ρ c T c (-1/4), where ρ c is the monomer density at T c. In addition, we also estimate T c from a Hansen-Verlet-like criterion and MCT calculations based on structural input from the simulation. For our polymer model both the Hansen-Verlet criterion and the MCT calculations suggest T c to decrease with increasing chain length, in contrast to the direct analysis of the simulation data.

The effects of an energy efficiency retrofit on indoor air quality.

To investigate the impacts of an energy efficiency retrofit, indoor air quality and resident health were evaluated at a low-income senior housing apartment complex in Phoenix, Arizona, before and after a green energy building renovation. Indoor and outdoor air quality sampling was carried out simultaneously with a questionnaire to characterize personal habits and general health of residents. Measured indoor formaldehyde levels before the building retrofit routinely exceeded reference exposure limits, but in the long-term follow-up sampling, indoor formaldehyde decreased for the entire study population by a statistically significant margin. Indoor PM levels were dominated by fine particles and showed a statistically significant decrease in the long-term follow-up sampling within certain resident subpopulations (i.e. residents who report smoking and residents who had lived longer at the apartment complex).

Long-Term Observations of Nitrogen and Phosphorus Export in Paired-Agricultural Watersheds under Controlled and Conventional Tile Drainage.

Controlled tile drainage (CTD) regulates water and nutrient export from tile drainage systems. Observations of the effects of CTD imposed en masse at watershed scales are needed to determine the effect on downstream receptors. A paired-watershed approach was used to evaluate the effect of field-to-field CTD at the watershed scale on fluxes and flow-weighted mean concentrations (FWMCs) of N and P during multiple growing seasons. One watershed (467-ha catchment area) was under CTD management (treatment [CTD] watershed); the other (250-ha catchment area) had freely draining or uncontrolled tile drainage (UCTD) (reference [UCTD] watershed). The paired agricultural watersheds are located in eastern Ontario, Canada. Analysis of covariance and paired tests were used to assess daily fluxes and FWMCs during a calibration period when CTD intervention on the treatment watershed was minimal (2005-2006, when only 4-10% of the tile-drained area was under CTD) and a treatment period when the treatment (CTD) watershed had prolific CTD intervention (2007-2011 when 82% of tile drained fields were controlled, occupying >70% of catchment area). Significant linear regression slope changes assessed using ANCOVA ( ≤ 0.1) for daily fluxes from upstream and downstream monitoring sites pooled by calibration and treatment period were -0.06 and -0.20 (stream water) (negative values represent flux declines in CTD watershed), -0.59 and -0.77 (NH-N), -0.14 and -0.15 (NO-N), -1.77 and -2.10 (dissolved reactive P), and -0.28 and 0.45 (total P). Total P results for one site comparison contrasted with other findings likely due to unknown in-stream processes affecting total P loading, not efficacy of CTD. The FWMC results were mixed and inconclusive but suggest physical abatement by CTD is the means by which nutrient fluxes are predominantly reduced at these scales. Overall, our study results indicate that CTD is an effective practice for reducing watershed scale fluxes of stream water, N, and P during the growing season.

Rainfall-induced runoff from exposed streambed sediments: an important source of water pollution.

When surface water levels decline, exposed streambed sediments can be mobilized and washed into the water course when subjected to erosive rainfall. In this study, rainfall simulations were conducted over exposed sediments along stream banks at four distinct locations in an agriculturally dominated river basin with the objective of quantifying the potential for contaminant loading from these often overlooked runoff source areas. At each location, simulations were performed at three different sites. Nitrogen, phosphorus, sediment, fecal indicator bacteria, pathogenic bacteria, and microbial source tracking (MST) markers were examined in both prerainfall sediments and rainfall-induced runoff water. Runoff generation and sediment mobilization occurred quickly (10-150 s) after rainfall initiation. Temporal trends in runoff concentrations were highly variable within and between locations. Total runoff event loads were considered large for many pollutants considered. For instance, the maximum observed total phosphorus runoff load was on the order of 1.5 kg ha. Results also demonstrate that runoff from exposed sediments can be a source of pathogenic bacteria. spp. and spp. were present in runoff from one and three locations, respectively. Ruminant MST markers were also present in runoff from two locations, one of which hosted pasturing cattle with stream access. Overall, this study demonstrated that rainfall-induced runoff from exposed streambed sediments can be an important source of surface water pollution.

High-resolution free-breathing automated quantitative myocardial perfusion by cardiovascular magnetic resonance for the detection of functionally significant coronary artery disease.

AIMS: Current assessment of myocardial ischaemia from stress perfusion cardiovascular magnetic resonance (SP-CMR) largely relies on visual interpretation. This study investigated the use of high-resolution free-breathing SP-CMR with automated quantitative mapping in the diagnosis of coronary artery disease (CAD). Diagnostic performance was evaluated against invasive coronary angiography (ICA) with fractional flow reserve (FFR) measurement. METHODS AND RESULTS: Seven hundred and three patients were recruited for SP-CMR using the research sequence at 3 Tesla. Of those receiving ICA within 6 months, 80 patients had either FFR measurement or identification of a chronic total occlusion (CTO) with inducible perfusion defects seen on SP-CMR. Myocardial blood flow (MBF) maps were automatically generated in-line on the scanner following image acquisition at hyperaemic stress and rest, allowing myocardial perfusion reserve (MPR) calculation. Seventy-five coronary vessels assessed by FFR and 28 vessels with CTO were evaluated at both segmental and coronary territory level. Coronary territory stress MBF and MPR were reduced in FFR-positive (≤0.80) regions [median stress MBF: 1.74 (0.90-2.17) mL/min/g; MPR: 1.67 (1.10-1.89)] compared with FFR-negative regions [stress MBF: 2.50 (2.15-2.95) mL/min/g; MPR 2.35 (2.06-2.54) P < 0.001 for both]. Stress MBF ≤ 1.94 mL/min/g and MPR ≤ 1.97 accurately detected FFR-positive CAD on a per-vessel basis (area under the curve: 0.85 and 0.96, respectively; P < 0.001 for both). CONCLUSION: A novel scanner-integrated high-resolution free-breathing SP-CMR sequence with automated in-line perfusion mapping is presented which accurately detects functionally significant CAD.

Priorities, opportunities, and challenges for integrating microorganisms into Earth system models for climate change prediction.

Climate change jeopardizes human health, global biodiversity, and sustainability of the biosphere. To make reliable predictions about climate change, scientists use Earth system models (ESMs) that integrate physical, chemical, and biological processes occurring on land, the oceans, and the atmosphere. Although critical for catalyzing coupled biogeochemical processes, microorganisms have traditionally been left out of ESMs. Here, we generate a "top 10" list of priorities, opportunities, and challenges for the explicit integration of microorganisms into ESMs. We discuss the need for coarse-graining microbial information into functionally relevant categories, as well as the capacity for microorganisms to rapidly evolve in response to climate-change drivers. Microbiologists are uniquely positioned to collect novel and valuable information necessary for next-generation ESMs, but this requires data harmonization and transdisciplinary collaboration to effectively guide adaptation strategies and mitigation policy.