Marine dissolved organic carbon (DOC) exhibits a spectrum of reactivity, from very fast turnover of the most bioavailable forms in the surface ocean to long-lived materials circulating within the ...ocean abyss. These disparate reactivities group DOC by fractions with distinctive functions in the cycling of carbon, ranging from support of the microbial loop to involvement in the biological pump to a hypothesized major source/sink of atmospheric CO(2) driving paleoclimate variability. Here, the major fractions constituting the global ocean's recalcitrant DOC pool are quantitatively and qualitatively characterized with reference to their roles in carbon biogeochemistry. A nomenclature for the fractions is proposed based on those roles.
We present a detailed report on sterile neutrino oscillation and 235Uν¯e energy spectrum measurement results from the PROSPECT experiment at the highly enriched High Flux Isotope Reactor (HFIR) at ...Oak Ridge National Laboratory. In 96 calendar days of data taken at an average baseline distance of 7.9 m from the center of the 85 MW HFIR core, the PROSPECT detector has observed more than 50,000 interactions of νe produced in beta decays of 235U fission products. New limits on the oscillation of ν¯e to light sterile neutrinos have been set by comparing the detected energy spectra of ten reactor-detector baselines between 6.7 and 9.2 meters. Measured differences in energy spectra between baselines show no statistically significant indication of ν¯e to sterile neutrino oscillation and disfavor the reactor antineutrino anomaly best-fit point at the 2.5σ confidence level. The reported 235U ν¯e energy spectrum measurement shows excellent agreement with energy spectrum models generated via conversion of the measured 235U beta spectrum, with a χ2/d.o.f. of 31/31. PROSPECT is able to disfavor at 2.4σ confidence level the hypothesis that 235U ν¯e are solely responsible for spectrum discrepancies between model and data obtained at commercial reactor cores. A data-model deviation in PROSPECT similar to that observed by commercial core experiments is preferred with respect to no observed deviation, at a 2.2σ confidence level.
Colored dissolved organic matter (CDOM), also referred to as gelbstoff, gilvin, or yellow matter, has long been known to be an important component of the optical properties of coastal and estuarine ...environments. However, an understanding of the processes regulating its global distribution and variability, its relationship to the total pool of dissolved organic carbon (DOC), and its influence on light availability remain largely unexplored. Satellite imagery from the Sea‐viewing Wide Field‐of‐view Sensor (SeaWiFS) is used to characterize the global distribution of light absorption due to colored detrital and dissolved materials (CDM). The quantity CDM is considered as it is not yet possible to differentiate CDOM and detrital particulate absorption from ocean color spectra on a routine basis. Nonetheless, analysis of an extensive field data set indicates that detrital particulates make only a small contribution to CDM. A comparison of coincident field observations of CDM with SeaWiFS retrievals shows good agreement, indicating that the present procedures perform well. To first order, the basin‐scale CDM distribution reflects patterns of wind‐driven vertical circulation of the gyres modulated by a meridional trend of increasing CDM toward higher latitudes. The global CDM distribution appears regulated by a coupling of biological, photochemical, and physical oceanographic processes all acting on a local scale, and greater than 50% of blue light absorption is controlled by CDM. Significant differences in both CDM concentration and its contribution to blue light absorption are found spatially among the major ocean basins and temporally on variety of timescales. Significant impacts of riverine discharges can be discerned, although their effects are largely localized. Basin‐scale distributions of CDM and DOC are largely unrelated, indicating that CDM is a small and highly variable fraction of the global DOC pool. This first view of the global CDM distribution opens many new doors for the quantification of global marine photoprocesses using satellite ocean color data.
The deposition of anthropogenic nitrogen (N) species is believed to have a significant impact on the oligotrophic North Atlantic, but the magnitude of ecological effects remains uncertain because the ...deposition of water soluble organic N (WSON) is poorly quantified. Here we present measurements of water soluble inorganic N (WSIN) and WSON in aerosol and rain at two subtropical North Atlantic time series sites: Barbados and Miami. WSON total deposition rates ranged from 17.9 mmol m−2 yr−1 to 49.6 mmol m−2 yr−1, contributing on average only 6–14% of total N deposition, less than half the poorly constrained global average which is typically cited as 30%. On an event basis, biomass burning and dust events yielded the largest concentrations of WSON. However, biomass burning was relatively infrequent and highly variable in composition, and much of the organic N associated with dust appeared to be externally adsorbed from pollution sources. Conversely, in Miami pollution made relatively small contributions of WSON on an event basis, but impacts were relatively frequent, making pollution one of the largest sources of WSON during the year. The largest contributor to WSON was volatile basic organic N (VBON) species, which were present at concentrations 1–2 times higher than particulate WSON. Despite VBON inputs, samples associated with pollution‐source trajectories yielded much more inorganic N than WSON. Consequently, we would expect that in the future as anthropogenic N emissions increase, inorganic nitrogen will remain the dominant form of N that is deposited to the western North Atlantic.
Key Points
Regionally, total N deposition contains only 6–14% water soluble organic N
Volatile basic organic N forms a large portion of WSON
Inorganic nitrogen will likely remain the dominant form of N deposited
DISSOLVED ORGANIC MATTER IN THE OCEAN HANSELL, DENNIS A.; CARLSON, CRAIG A.; REPETA, DANIEL J. ...
Oceanography (Washington, D.C.),
12/2009, Letnik:
22, Številka:
4
Journal Article
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Containing as much carbon as the atmosphere, marine dissolved organic matter is one of Earth's major carbon reservoirs. With invigoration of scientific inquiries into the global carbon cycle, our ...ignorance of its role in ocean biogeochemistry became untenable. Rapid mobilization of relevant research two decades ago required the community to overcome early false leads, but subsequent progress in examining the global dynamics of this material has been steady. Continuous improvements in analytical skill coupled with global ocean hydrographic survey opportunities resulted in the generation of thousands of measurements throughout the major ocean basins. Here, observations and model results provide new insights into the large-scale variability of dissolved organic carbon, its contribution to the biological pump, and its deep ocean sinks.
Diffuse parenchymal lung disease represents a diverse and challenging group of pulmonary disorders. A consistent diagnostic approach to diffuse parenchymal lung disease is crucial if clinical trial ...data are to be applied to individual patients. We aimed to evaluate inter-multidisciplinary team agreement for the diagnosis of diffuse parenchymal lung disease.
We did a multicentre evaluation of clinical data of patients who presented to the interstitial lung disease unit of the Royal Brompton and Harefield NHS Foundation Trust (London, UK; host institution) and required multidisciplinary team meeting (MDTM) characterisation between March 1, 2010, and Aug 31, 2010. Only patients whose baseline clinical, radiological, and, if biopsy was taken, pathological data were undertaken at the host institution were included. Seven MDTMs, consisting of at least one clinician, radiologist, and pathologist, from seven countries (Denmark, France, Italy, Japan, Netherlands, Portugal, and the UK) evaluated cases of diffuse parenchymal lung disease in a two-stage process between Jan 1, and Oct 15, 2015. First, the clinician, radiologist, and pathologist (if lung biopsy was completed) independently evaluated each case, selected up to five differential diagnoses from a choice of diffuse lung diseases, and chose likelihoods (censored at 5% and summing to 100% in each case) for each of their differential diagnoses, without inter-disciplinary consultation. Second, these specialists convened at an MDTM and reviewed all data, selected up to five differential diagnoses, and chose diagnosis likelihoods. We compared inter-observer and inter-MDTM agreements on patient first-choice diagnoses using Cohen's kappa coefficient (κ). We then estimated inter-observer and inter-MDTM agreement on the probability of diagnosis using weighted kappa coefficient (κw). We compared inter-observer and inter-MDTM confidence of patient first-choice diagnosis. Finally, we evaluated the prognostic significance of a first-choice diagnosis of idiopathic pulmonary fibrosis (IPF) versus not IPF for MDTMs, clinicians, and radiologists, using univariate Cox regression analysis.
70 patients were included in the final study cohort. Clinicians, radiologists, pathologists, and the MDTMs assigned their patient diagnoses between Jan 1, and Oct 15, 2015. IPF made up 88 (18%) of all 490 MDTM first-choice diagnoses. Inter-MDTM agreement for first-choice diagnoses overall was moderate (κ=0·50). Inter-MDTM agreement on diagnostic likelihoods was good for IPF (κw=0·71 IQR 0·64-0·77) and connective tissue disease-related interstitial lung disease (κw=0·73 0·68-0·78); moderate for non-specific interstitial pneumonia (NSIP; κw=0·42 0·37-0·49); and fair for hypersensitivity pneumonitis (κw=0·29 0·24-0·40). High-confidence diagnoses (>65% likelihood) of IPF were given in 68 (77%) of 88 cases by MDTMs, 62 (65%) of 96 cases by clinicians, and in 57 (66%) of 86 cases by radiologists. Greater prognostic separation was shown for an MDTM diagnosis of IPF than compared with individual clinician's diagnosis of this disease in five of seven MDTMs, and radiologist's diagnosis of IPF in four of seven MDTMs.
Agreement between MDTMs for diagnosis in diffuse lung disease is acceptable and good for a diagnosis of IPF, as validated by the non-significant greater prognostic separation of an IPF diagnosis made by MDTMs than the separation of a diagnosis made by individual clinicians or radiologists. Furthermore, MDTMs made the diagnosis of IPF with higher confidence and more frequently than did clinicians or radiologists. This difference is of particular importance, because accurate and consistent diagnoses of IPF are needed if clinical outcomes are to be optimised. Inter-multidisciplinary team agreement for a diagnosis of hypersensitivity pneumonitis is low, highlighting an urgent need for standardised diagnostic guidelines for this disease.
National Institute of Health Research, Imperial College London.
Global ship-based programs, with highly accurate, full water column physical and biogeochemical observations repeated decadally since the 1970s, provide a crucial resource for documenting ocean ...change. The ocean, a central component of Earth's climate system, is taking up most of Earth's excess anthropogenic heat, with about 19% of this excess in the abyssal ocean beneath 2,000 m, dominated by Southern Ocean warming. The ocean also has taken up about 27% of anthropogenic carbon, resulting in acidification of the upper ocean. Increased stratification has resulted in a decline in oxygen and increase in nutrients in the Northern Hemisphere thermocline and an expansion of tropical oxygen minimum zones. Southern Hemisphere thermocline oxygen increased in the 2000s owing to stronger wind forcing
and ventilation. The most recent decade of global hydrography has mapped dissolved organic carbon, a large, bioactive reservoir, for the first time and quantified its contribution to export production (∼20%) and deep-ocean oxygen utilization. Ship-based measurements also show that vertical diffusivity increases from a minimum in the thermocline to a maximum within the bottom 1,500 m, shifting our physical paradigm of the ocean's overturning circulation.
This document is an international evidence-based guideline on the diagnosis and management of idiopathic pulmonary fibrosis, and is a collaborative effort of the American Thoracic Society, the ...European Respiratory Society, the Japanese Respiratory Society, and the Latin American Thoracic Association. It represents the current state of knowledge regarding idiopathic pulmonary fibrosis (IPF), and contains sections on definition and epidemiology, risk factors, diagnosis, natural history, staging and prognosis, treatment, and monitoring disease course. For the diagnosis and treatment sections, pragmatic GRADE evidence-based methodology was applied in a question-based format. For each diagnosis and treatment question, the committee graded the quality of the evidence available (high, moderate, low, or very low), and made a recommendation (yes or no, strong or weak). Recommendations were based on majority vote. It is emphasized that clinicians must spend adequate time with patients to discuss patients' values and preferences and decide on the appropriate course of action.
We report four profiles of the radiocarbon content of dissolved organic carbon (DOC) spanning the South Indian Ocean (SIO), ranging from the Polar Front (56°S) to the subtropics (29°S). Surface ...waters held mean DOC Δ14C values of −426 ± 6‰ (~4,400 14C years) at the Polar Front and DOC Δ14C values of −252 ± 22‰ (~2,000 14C years) in the subtropics. At depth, Circumpolar Deep Waters held DOC Δ14C values of −491 ± 13‰ (~5,400 years), while values in Indian Deep Water were more depleted, holding DOC Δ14C values of −503 ± 8‰ (~5,600 14C years). High‐salinity North Atlantic Deep Water intruding into the deep SIO had a distinctly less depleted DOC Δ14C value of −481 ± 8‰ (~5,100 14C years). We use multiple linear regression to assess the dynamics of DOC Δ14C values in the deep Indian Ocean, finding that their distribution is characteristic of water masses in that region.
Key Points
14C ages of DOC in the South Indian Ocean range from 2,000 to 4,400 14C years at the surface and reach ~5,600 14C years at depth
There are distinct 14C signatures of DOC in the deep Indian Ocean's water masses
DOC 14C gradients in deep waters are consistent with their respective placement in overturning circulation
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