Airborne observations over the North Atlantic Ocean reveal the importance of gas-phase urea in the atmosphere.

Reduced nitrogen (N) is central to global biogeochemistry, yet there are large uncertainties surrounding its sources and rate of cycling. Here, we present observations of gas-phase urea (CO(NH2)2) in the atmosphere from airborne high-resolution mass spectrometer measurements over the North Atlantic Ocean. We show that urea is ubiquitous in the lower troposphere in the summer, autumn, and winter but was not detected in the spring. The observations suggest that the ocean is the primary emission source, but further studies are required to understand the responsible mechanisms. Urea is also observed aloft due to long-range transport of biomass-burning plumes. These observations alongside global model simulations point to urea being an important, and currently unaccounted for, component of reduced-N to the remote marine atmosphere. Airborne transfer of urea between nutrient-rich and -poor parts of the ocean can occur readily and could impact ecosystems and oceanic uptake of carbon dioxide, with potentially important climate implications.

Characterizing the Particle Composition and Cloud Condensation Nuclei from Shipping Emission in Western Europe.

Commercial shipping is considered as an important source of air pollution and cloud condensation nuclei (CCN). To assess the climatic and environmental impacts of shipping, detailed characterization of ship plumes near the point of emission and understanding of ship plume evolution further downwind are essential. This airborne measurement study presents the online characterization of particulate phase ship emissions in the region of Western Europe in 2019 prior to new international sulfur emission controls becoming enacted. More than 30 ships from both the sulfur emission control area (SECA) in the English Channel and the open sea (OS) are measured and compared. Ships within the SECA emitted much less sulfate (SO4) compared with those at OS. When shifted to a lower apparent fuel sulfur content (FSC) at similar engine loads, the peak of the fresh ship emitting the particle number size distribution shifted from around 60-80 nm in diameter to below 40 nm in diameter. The emission factors (EFs) of sulfate are predicted to decrease by around 94% after the 2020 regulation on ship sulfur emission in the open ocean. The EFs of refractory black carbon (rBC) and organic compounds (Org) do not appear to be directly affected by the lower sulfur contents. The total number concentration for condensation nuclei (CN) >2.5 nm and >0.1 µm are predicated to be reduced by 69 and 56%, respectively. Measured plume evolution results indicate that the S(IV) to S(VI) conversion rate was around 23.4% per hour at the beginning of plume evolution, and the CCN and CN >2.5 nm ratio increased with plume age primarily due to condensation and coagulation. We estimate that the new sulfur emission regulation will lead to a reduction of more than 80% in CCN from fresh ship emissions. The ship-emitted EFs results presented here will also inform emission inventories, policymaking, climate, and human health studies.

How should we regulate artificial intelligence?

Using artificial intelligence (AI) technology to replace human decision-making will inevitably create new risks whose consequences are unforeseeable. This naturally leads to calls for regulation, but I argue that it is too early to attempt a general system of AI regulation. Instead, we should work incrementally within the existing legal and regulatory schemes which allocate responsibility, and therefore liability, to persons. Where AI clearly creates risks which current law and regulation cannot deal with adequately, then new regulation will be needed. But in most cases, the current system can work effectively if the producers of AI technology can provide sufficient transparency in explaining how AI decisions are made. Transparency ex post can often be achieved through retrospective analysis of the technology's operations, and will be sufficient if the main goal is to compensate victims of incorrect decisions. Ex ante transparency is more challenging, and can limit the use of some AI technologies such as neural networks. It should only be demanded by regulation where the AI presents risks to fundamental rights, or where society needs reassuring that the technology can safely be used. Masterly inactivity in regulation is likely to achieve a better long-term solution than a rush to regulate in ignorance.This article is part of a discussion meeting issue 'The growing ubiquity of algorithms in society: implications, impacts and innovations'.

Exogenous glucagon-like peptide-1 acts in sites supplied by the cranial mesenteric artery to reduce meal size and prolong the intermeal interval in rats.

Three experiments were done to better assess the gastrointestinal (GI) site(s) of action of GLP-1 on food intake in rats. First, near-spontaneous nocturnal chow meal size (MS), intermeal intervals (IMI) length and satiety ratios (SR = MS/IMI) were measured after infusion of saline, 0.025 or 0.5 nmol/kg GLP-1 into the celiac artery (CA, supplying the stomach and upper duodenum), cranial mesenteric artery (CMA, supplying small and all of the large intestine except the rectum), femoral artery (FA, control) or portal vein (PV, control). Second, infusion of 0.5 nmol/kg GLP-1 was tested after pretreatment with the GLP-1 receptor (GLP-1R) antagonist exendin-4(3-39) via the same routes. Third, the regional distribution of GLP-1R in the rat GI tract was determined using rtPCR. CA, CMA and FA GLP-1 reduced first MS relative to saline, with the CMA route more effective than the others. Only CMA GLP-1 prolonged the IMI. None of the infusions affected second MS or later eating. CA and CMA GLP-1 increased the SR, with the CMA route more effective than the CA route. CMA exendin-4 (3-39) infusion reduced the effect of CMA GLP-1. Finally GLP-1R expression was found throughout the GI tract. The results suggest that exogenous GLP-1 acts in multiple GI sites to reduce feeding under our conditions and that GLP-1R in the area supplied by the CMA, i.e., the small and part of the large intestine, plays the leading role.

Detection and formation scenario of citric acid, pyruvic acid, and other possible metabolism precursors in carbonaceous meteorites.

Carbonaceous meteorites deliver a variety of organic compounds to Earth that may have played a role in the origin and/or evolution of biochemical pathways. Some apparently ancient and critical metabolic processes require several compounds, some of which are relatively labile such as keto acids. Therefore, a prebiotic setting for any such individual process would have required either a continuous distant source for the entire suite of intact precursor molecules and/or an energetic and compact local synthesis, particularly of the more fragile members. To date, compounds such as pyruvic acid, oxaloacetic acid, citric acid, isocitric acid, and α-ketoglutaric acid (all members of the citric acid cycle) have not been identified in extraterrestrial sources or, as a group, as part of a "one pot" suite of compounds synthesized under plausibly prebiotic conditions. We have identified these compounds and others in carbonaceous meteorites and/or as low temperature (laboratory) reaction products of pyruvic acid. In meteorites, we observe many as part of three newly reported classes of compounds: keto acids (pyruvic acid and homologs), hydroxy tricarboxylic acids (citric acid and homologs), and tricarboxylic acids. Laboratory syntheses using (13)C-labeled reactants demonstrate that one compound alone, pyruvic acid, can produce several (nonenzymatic) members of the citric acid cycle including oxaloacetic acid. The isotopic composition of some of the meteoritic keto acids points to interstellar or presolar origins, indicating that such compounds might also exist in other planetary systems.

Extensive field evidence for the release of HONO from the photolysis of nitrate aerosols.

Particulate nitrate ([Formula: see text]) has long been considered a permanent sink for NOx (NO and NO2), removing a gaseous pollutant that is central to air quality and that influences the global self-cleansing capacity of the atmosphere. Evidence is emerging that photolysis of [Formula: see text] can recycle HONO and NOx back to the gas phase with potentially important implications for tropospheric ozone and OH budgets; however, there are substantial discrepancies in "renoxification" photolysis rate constants. Using aircraft and ground-based HONO observations in the remote Atlantic troposphere, we show evidence for renoxification occurring on mixed marine aerosols with an efficiency that increases with relative humidity and decreases with the concentration of [Formula: see text], thus largely reconciling the very large discrepancies in renoxification photolysis rate constants found across multiple laboratory and field studies. Active release of HONO from aerosol has important implications for atmospheric oxidants such as OH and O3 in both polluted and clean environments.

Annotating Argument Schemes.

Argument schemes are abstractions substantiating the inferential connection between premise(s) and conclusion in argumentative communication. Identifying such conventional patterns of reasoning is essential to the interpretation and evaluation of argumentation. Whether studying argumentation from a theory-driven or data-driven perspective, insight into the actual use of argumentation in communicative practice is essential. Large and reliably annotated corpora of argumentative discourse to quantitatively provide such insight are few and far between. This is all the more true for argument scheme corpora, which tend to suffer from a combination of limited size, poor validation, and the use of ad hoc restricted typologies. In the current paper, we describe the annotation of schemes on the basis of two distinct classifications: Walton's taxonomy of argument schemes, and Wagemans' Periodic Table of Arguments. We describe the annotation procedure for each, and the quantitative characteristics of the resulting annotated text corpora. In doing so, we extend the annotation of the preexisting US2016 corpus of televised election debates, resulting in, to the best of our knowledge, the two largest consistently annotated corpora of schemes in argumentative dialogue publicly available. Based on evaluation in terms of inter-annotator agreement, we propose further improvements to the guidelines for annotating schemes: the argument scheme key, and the Argument Type Identification Procedure.

Health care personnel exposure to a patient with asymptomatic SARS-CoV2 infection during a prolonged surgical intervention.

There is ongoing debate regarding the role of aerosols in the transmission of SARS-CoV2 in the health care environment. Here, we report a case in which multiple operating room health care providers were exposed to a patient with asymptomatic SARS-CoV2 infection during a prolonged orthopedic surgical intervention and had no evidence of COVID-19 during the 14-day post-exposure period.

Opportunistic bone density screening for the abdominal radiologist using colored CT images: a pilot retrospective study.

PURPOSE: The purpose of the study was to develop an accurate and reproducible method for detecting low spinal bone density on abdominal CT images. METHODS: For this IRB-approved HIPAA-compliant single-center retrospective study, nonenhanced CT images of the lower abdomen were obtained in 631 African-American participants. Mean attenuation of L3/L4 was associated with quantitative CT bone density (QCT) in a randomly selected training cohort (N = 511), and receiver operating characteristics analysis was used to identify the optimal mean attenuation threshold for differentiating normal from low bone density. Custom image processing software was used to generate grayscale and colored CT images of the midline spine, with green for normal and red for low bone density. Five radiologists independently assessed bone density at L3/L4 in a validation cohort (N = 120) using various methods: QCT, visual assessment of sagittal grayscale images (Grayscale), quantitative measurement of mean attenuation on a midline sagittal image (Attenuation), and visual assessment of a midline sagittal colored image (Color). Accuracy was calculated using the average QCT bone density as a reference standard. Inter-observer agreement was assessed using intraclass correlation coefficient (ICC). RESULTS: The optimal mean attenuation threshold for differentiating normal from low bone density at L3/L4 was 145 Hounsfield Units. The average accuracy of Grayscale, Attenuation, and Color methods was 58, 87, and 91% (p < 0.001), respectively. Inter-observer agreement was poor for Grayscale (ICC: 0.20; 95% CI 0.12, 0.28) and excellent for both Attenuation (ICC: 0.85; 95% CI 0.73, 0.91) and Color methods (ICC: 0.87; 95% CI 0.83, 0.90). CONCLUSION: Detection of low spinal bone density using colored abdominal CT images was highly accurate and reproducible.

Effect of the mutation rate and background size on the quality of pathogen identification.

MOTIVATION: Genomic-based methods have significant potential for fast and accurate identification of organisms or even genes of interest in complex environmental samples (air, water, soil, food, etc.), especially when isolation of the target organism cannot be performed by a variety of reasons. Despite this potential, the presence of the unknown, variable and usually large quantities of background DNA can cause interference resulting in false positive outcomes. RESULTS: In order to estimate how the genomic diversity of the background (total length of all of the different genomes present in the background), target length and target mutation rate affect the probability of misidentifications, we introduce a mathematical definition for the quality of an individual signature in the presence of a background based on its length and number of mismatches needed to transform the signature into the closest subsequence present in the background. This definition, in conjunction with a probabilistic framework, allows one to predict the minimal signature length required to identify the target in the presence of different sizes of backgrounds and the effect of the target's mutation rate on the quality of its identification. The model assumptions and predictions were validated using both Monte Carlo simulations and real genomic data examples. The proposed model can be used to determine appropriate signature lengths for various combinations of target and background genome sizes. It also predicted that any genomic signatures will be unable to identify target if its mutation rate is >5%. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

Early experience of the use of short message service (SMS) technology in routine clinical care.

OBJECTIVE: To conduct a technical appraisal and qualitative interviews with short message service (SMS--mobile phone text message) users in mainstream health care. DESIGN: Observation of service usage followed by in-depth semi-structured interviews. SETTING: A National Health Service (NHS) general practice in Scotland. PARTICIPANTS: One hundred and eighty patients registered. MAIN OUTCOME MEASURES: Service utilisation and patients' views. RESULTS: It was technically feasible to open up access to mainstream NHS general practice services using SMS for appointment booking, repeat prescription ordering, clinical enquiries and remote access to the core clinical summary. CONCLUSION: Patients were able to use SMS services responsibly and found automation of prescription ordering particularly useful. Service utilisation was modest and did not adversely impact on the workload of general practitioners (GPs) or their staff.

The Argument Web: an Online Ecosystem of Tools, Systems and Services for Argumentation.

The Argument Web is maturing as both a platform built upon a synthesis of many contemporary theories of argumentation in philosophy and also as an ecosystem in which various applications and application components are contributed by different research groups around the world. It already hosts the largest publicly accessible corpora of argumentation and has the largest number of interoperable and cross compatible tools for the analysis, navigation and evaluation of arguments across a broad range of domains, languages and activity types. Such interoperability is key in allowing innovative combinations of tool and data reuse that can further catalyse the development of the field of computational argumentation. The aim of this paper is to summarise the key foundations, the recent advances and the goals of the Argument Web, with a particular focus on demonstrating the relevance to, and roots in, philosophical argumentation theory.

Multi-level computational methods for interdisciplinary research in the HathiTrust Digital Library.

We show how faceted search using a combination of traditional classification systems and mixed-membership topic models can go beyond keyword search to inform resource discovery, hypothesis formulation, and argument extraction for interdisciplinary research. Our test domain is the history and philosophy of scientific work on animal mind and cognition. The methods can be generalized to other research areas and ultimately support a system for semi-automatic identification of argument structures. We provide a case study for the application of the methods to the problem of identifying and extracting arguments about anthropomorphism during a critical period in the development of comparative psychology. We show how a combination of classification systems and mixed-membership models trained over large digital libraries can inform resource discovery in this domain. Through a novel approach of "drill-down" topic modeling-simultaneously reducing both the size of the corpus and the unit of analysis-we are able to reduce a large collection of fulltext volumes to a much smaller set of pages within six focal volumes containing arguments of interest to historians and philosophers of comparative psychology. The volumes identified in this way did not appear among the first ten results of the keyword search in the HathiTrust digital library and the pages bear the kind of "close reading" needed to generate original interpretations that is the heart of scholarly work in the humanities. Zooming back out, we provide a way to place the books onto a map of science originally constructed from very different data and for different purposes. The multilevel approach advances understanding of the intellectual and societal contexts in which writings are interpreted.

Provider Bias Impacts Tidal Volume Selection and Ventilator Days in Trauma Patients.

BACKGROUND: The ARDSnet (Acute Respiratory Distress Syndrome Clinical Network) study demonstrated that low tidal volume (Vt) reduces mortality from ARDS. It is unknown whether low Vt is beneficial in at-risk trauma patients. We hypothesized that Vt selection would be low in accordance with ARDSnet criteria and that subsequent outcomes would be improved. STUDY DESIGN: A 1-year retrospective observational study was conducted on all trauma patients aged 15 years and older and on mechanical ventilation for 48 hours or longer, excluding those with cardiopulmonary disease. Using maximum Vt, we identified low and high Vt groups (≤8 mL/predicted body weight (PBW) and >8 mL/PBW). Data collected included demographic characteristics, lengths of stay, ventilator and ICU days, ARDS, and other complications. RESULTS: A total of 364 patients were identified and organized into low Vt (n = 181) and high Vt (n = 183) groups. There was no difference between groups in age, Injury Severity Score, Glasgow Coma Scale, or mechanism of injury. The rate of ARDS was the same in each group. Patients with a high Vt had lower PBW (63.1 ± 8.8 vs 71.7 ± 6.9; p < 0.001), higher BMI(29.7 ± 6.9 kg/m(2) vs 26.6 ± 6.5 kg/m(2); p < 0.001), and were more likely to be female. Height was inversely correlated with Vt (r(2) = -0.579; p < 0.001). The high Vt group experienced longer ICU stays (9.9 ± 8.8 days vs 8.1 ± 7.9 days; p = 0.045) and more ventilator days (8.55 ± 10.5 days vs 6.14 ± 7.4 days; p = 0.015). CONCLUSIONS: Trauma patients receiving high Vt were shorter, had higher BMI, and were more likely to be female. The consequences included longer ICU stays and more ventilator days. Formal calculation of PBW and subsequent Vt is advocated.

Assessment of brachial artery blood flow across the cardiac cycle: retrograde flows during cycle ergometry.

We describe a novel software system that utilizes automated algorithms to perform edge detection and wall tracking of high-resolution B-mode arterial ultrasound images, combined with synchronized Doppler waveform envelope analysis, to calculate conduit arterial blood flow (BF) across the cardiac cycle. Furthermore, we describe changes in brachial arterial BF to the resting forearm during incremental cycle ergometry in eight subjects. During exercise, peak BF during the cardiac cycle increased at each workload (P < 0.001), because of increased velocity in the presence of unaltered cross-sectional area. In contrast, mean BF calculated across each cardiac cycle decreased at lower workloads before increasing at 100 and 160 W (P < 0.001). Differences in the pattern of peak and mean cardiac cycle flows were due to the influence of retrograde diastolic flow, which had a larger impact on mean flows at lower workloads. In conclusion, BF can be measured with high temporal resolution across the cardiac cycle in humans. Resting brachial arterial flow, including retrograde flow, increases during lower limb exercise.

Cultured autologous keratinocytes in suspension accelerate epithelial maturation in an in vivo wound model as measured by surface electrical capacitance.

BACKGROUND: Human epidermis serves as a protective covering against loss of endogenous fluids and exogenous microbial invasion. Cultured epithelial autograft suspensions have been used to enhance epithelialization to improve mortality, morbidity, and the overall quality of the scar. The measurement of surface electrical capacitance as an indicator of transepidermal water loss has been used in neonatology and dermatology to determine epidermal maturation. This tool has been used in a double-blind, randomized, controlled trial to compare the effects of cultured epithelial autograft in suspension on epidermal healing and maturation compared with a control in an in vivo partial thickness wound model. METHODS: In this double-blind, randomized, controlled trial (n = 8), the authors assessed the effect of cultured epithelial autograft on epidermal healing and maturation in standardized partial thickness wounds. Surface electrical capacitance was compared on 16 split-thickness skin graft donor sites treated with cultured epithelial autograft (n = 8) against controls treated with Dulbecco's Modified Eagle's Medium (n = 8) using a NOVA Dermaphase Meter at 4, 5, 6, and 7 days postoperatively. RESULTS: A statistically significant difference on continuous readings at days 5 (p = 0.012) and 7 (p = 0.036) and instantaneously on days 5 (p = 0.025) and 6 (p = 0.036) in surface electrical capacitance was observed in the cultured epithelial autograft over the Dulbecco's Modified Eagle's Medium-treated wounds. CONCLUSIONS: Measuring surface electrical capacitance provides an objective and repeatable method of assessing epidermal maturation. This study indicates that the rate of epithelialization and epidermal maturation is more rapid in partial thickness epidermal skin wounds treated with cultured epithelial autograft.