The most recent IPCC assessment has shown an important role for negative emissions technologies (NETs) in limiting global warming to 2 °C cost-effectively. However, a bottom-up, systematic, ...reproducible, and transparent literature assessment of the different options to remove CO2 from the atmosphere is currently missing. In part 1 of this three-part review on NETs, we assemble a comprehensive set of the relevant literature so far published, focusing on seven technologies: bioenergy with carbon capture and storage (BECCS), afforestation and reforestation, direct air carbon capture and storage (DACCS), enhanced weathering, ocean fertilisation, biochar, and soil carbon sequestration. In this part, part 2 of the review, we present estimates of costs, potentials, and side-effects for these technologies, and qualify them with the authors' assessment. Part 3 reviews the innovation and scaling challenges that must be addressed to realise NETs deployment as a viable climate mitigation strategy. Based on a systematic review of the literature, our best estimates for sustainable global NET potentials in 2050 are 0.5-3.6 GtCO2 yr−1 for afforestation and reforestation, 0.5-5 GtCO2 yr−1 for BECCS, 0.5-2 GtCO2 yr−1 for biochar, 2-4 GtCO2 yr−1 for enhanced weathering, 0.5-5 GtCO2 yr−1 for DACCS, and up to 5 GtCO2 yr−1 for soil carbon sequestration. Costs vary widely across the technologies, as do their permanency and cumulative potentials beyond 2050. It is unlikely that a single NET will be able to sustainably meet the rates of carbon uptake described in integrated assessment pathways consistent with 1.5 °C of global warming.
This study evaluates the dynamics of soil organic carbon (SOC) under perennial crops across the globe. It quantifies the effect of change from annual to perennial crops and the subsequent temporal ...changes in SOC stocks during the perennial crop cycle. It also presents an empirical model to estimate changes in the SOC content under crops as a function of time, land use, and site characteristics. We used a harmonized global dataset containing paired‐comparison empirical values of SOC and different types of perennial crops (perennial grasses, palms, and woody plants) with different end uses: bioenergy, food, other bio‐products, and short rotation coppice. Salient outcomes include: a 20‐year period encompassing a change from annual to perennial crops led to an average 20% increase in SOC at 0–30 cm (6.0 ± 4.6 Mg/ha gain) and a total 10% increase over the 0–100 cm soil profile (5.7 ± 10.9 Mg/ha). A change from natural pasture to perennial crop decreased SOC stocks by 1% over 0–30 cm (−2.5 ± 4.2 Mg/ha) and 10% over 0–100 cm (−13.6 ± 8.9 Mg/ha). The effect of a land use change from forest to perennial crops did not show significant impacts, probably due to the limited number of plots; but the data indicated that while a 2% increase in SOC was observed at 0–30 cm (16.81 ± 55.1 Mg/ha), a decrease in 24% was observed at 30–100 cm (−40.1 ± 16.8 Mg/ha). Perennial crops generally accumulate SOC through time, especially woody crops; and temperature was the main driver explaining differences in SOC dynamics, followed by crop age, soil bulk density, clay content, and depth. We present empirical evidence showing that the FAO perennialization strategy is reasonable, underscoring the role of perennial crops as a useful component of climate change mitigation strategies.
This global study shows that a change from annual to perennial crop leads to an increase in soil organic carbon (SOC) while a change from grassland or forest has the opposite effect. Perennial crops, especially woody crops, accumulate organic carbon in the soil through time. Temperature is the main driver explaining differences in SOC dynamics around the world. Perennial crops under current management can be a feasible climate change mitigation option.
Road dust resuspension is one of the main sources of particulate matter with impacts on air quality, health and climate. With the aim of characterising the thoracic fraction, a portable resuspension ...chamber was used to collect road dust from five main roads in Oporto and an urban tunnel in Braga, north of Portugal. The PM10 samples were analysed for: i) carbonates by acidification and quantification of the evolved CO2, ii) carbonaceous content (OC and EC) by a thermo-optical technique, iii) elemental composition by ICP-MS and ICP-AES after acid digestion, and iv) organic speciation by GC–MS. Dust loadings of 0.48±0.39mgPM10m−2 were obtained for asphalt paved roads. A much higher mean value was achieved in a cobbled pavement (50mgPM10m−2). In general, carbonates were not detected in PM10. OC and EC accounted for PM10 mass fractions up to 11% and 5%, respectively. Metal oxides accounted for 29±7.5% of the PM10 mass from the asphalt paved roads and 73% in samples from the cobbled street. Crustal and anthropogenic elements, associated with tyre and brake wear, dominated the inorganic fraction. PM10 comprised hundreds of organic constituents, including hopanoids, n-alkanes and other aliphatics, polycyclic aromatic hydrocarbons (PAH), alcohols, sterols, various types of acids, glycerol derivatives, lactones, sugars and derivatives, phenolic compounds and plasticizers. In samples from the cobbled street, these organic classes represented only 439μgg−1PM10, while for other pavements mass fractions up to 65mgg−1PM10 were obtained. Except for the cobbled street, on average, about 40% of the analysed organic fraction was composed of plasticizers. Although the risk via inhalation of PAH was found to be insignificant, the PM10 from some roads can contribute to an estimated excess of 332 to 2183 per million new cancer cases in adults exposed via ingestion and dermal contact.
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•Dust loadings<1mgPM10m−2 were obtained for asphalt paved roads.•These values are lower than those reported for other cities.•Dust loadings about 50 times higher were found for a cobbled pavement.•OC & EC accounted for small PM10 mass fractions, while inorganic components dominate.•OC comprised hundreds of organic constituents; plasticizers were the most abundant.
This review highlights key reactivities relying on C-C bond cleavages of cyclopropenes. Metal-catalyzed and metal-free transformations are covered in reactions involving direct ring-opening processes ...or transformations through nonisolable cyclopropane intermediates generated from cyclopropenes. Special emphasis is on the synthetic utility and mechanistic aspects of methodologies discussed along the revision. Different types of reactivities are covered in separate sections including generation of vinyl carbenes and their reactions, metathesis processes, heterocycles syntheses, S
Ar reactions, metalation-ring opening sequences, cycloadditions involving ring-cleavages or rearrangements. The focus is on results described from 2007 to the end of 2019, yet relevant pioneering transformations are eventually included.
•Effects of RMPs on SOC in woody crops were assessed using literature data.•Average SOC sequestration rate for all RMPs was 3.8tCha−1 yr−1.•C sequestration rates in olive orchard ranged 1.1 (CC) to ...5.3 (OA) t C ha−1 yr−1.•C sequestration rate in vineyards was 0.78tCha−1 yr−1 in CC management.•C sequestration rates were highest during the first years of the RMPs.
Mediterranean woody crops, such as olive and almond farming, and vineyards are usually cultivated in soils low in organic matter, with limited water availability and frequently on medium to steep slopes. Therefore, when conventionally cultivated, soils of these cropping systems are net sources of CO2 (throughout soil erosion and organic carbon mineralization). A promising option to sequester carbon (C) in these cropping systems is the implementation of recommended management practices (RMPs), which include plant cover in the inter-row area, minimum or no tillage and off- and on-farm organic matter amendments. However, the effects of RMPs on soil organic carbon (SOC) stocks in these cropping systems are widely overlooked, despite the critical importance of estimating their contribution on CO2 emissions for policy decisions in the agriculture sector in Mediterranean regions. We therefore conducted a meta-analysis to derive a C response ratio, soil C sequestration rate and soil C sequestration efficiency under RMPs, compared to conventional management of olive and almond orchards, and vineyards (144 data sets from 51 references). RMPs included organic amendments (OA), plant cover (CC) and a combination of the two (CMP). The highest soil C sequestration rate (5.3tCha−1 yr−1) was observed following the application OA in olive orchards (especially after olive mill pomace application), whereas CC management achieved the lowest C sequestration rates (1.1, 0.78 and 2.0tCha−1 yr−1, for olive orchards, vineyards and almond orchards, respectively). Efficiency of soil C sequestration was greater than 100% after OA and CMP managements, indicating that: i) some of the organic C inputs were unaccounted for, and ii) a positive feedback effect of the application of these amendments on SOC retention (e.g. reduction of soil erosion) and on protective mechanisms of the SOC which reduce CO2 emissions. Soil C sequestration rate tended to be highest during the first years after the change of the management and progressively decreased. Studies performed in Mediterranean sub-climates of low annual precipitation had lower values of soil C sequestration rate, likely due to a lower biomass production of the crop and other plant cover. Soil C sequestration rates in olive farming were much higher than that of vineyards, mainly due to the application of higher annual doses of organic amendments. The relatively high sequestration rate combined with the relative large spatial extent of these cropping system areas suggests that the adoption of RMPs is a sustainable and efficient measure to mitigate climate change.
The use of charcoal for cooking and heating can be a major source of air pollution and lead to a wide range of health outcomes. The aim of this study was to experimentally quantify and characterise ...the gaseous and particulate matter (PM2.5) emissions from charcoal combustion in a typical brick barbecue grill. The gaseous emission factors were 219 ± 44.8 g kg−1 for carbon monoxide (CO), 3.01 ± 0.698 g kg−1 for nitrogen oxides (NOx expressed as NO2), and 4.33 ± 1.53 gC kg−1 for total organic carbon (TOC). Particle emissions (7.38 ± 0.353 g kg−1 of dry charcoal burned) were of the same order of magnitude as those from traditional residential wood burning appliances. About 50% of the PM2.5 emitted had a carbonaceous nature while water soluble ions accounted, on average, for 17% of the particulate mass. Alkanes (C11–C16 and C23), hopanes, steranes and alkyl-PAHs accounted for small mass fractions of PM2.5. Phenolic compounds and saccharides represented the major particle-bond organic constituents. The high proportion of either resin acids or syringyl and vanillyl compounds is consistent with emissions from charred coniferous wood. The ratios between anhydrosugars for charcoal are much lower than the values reported for lignite combustion, but overlap those from other biomass burning sources.
•Speciation of PM2.5 in flue gas from charcoal combustion was obtained.•The carbonaceous content represented almost 50% of PM2.5 mass.•Potassium, sodium and chloride were the dominant water soluble ions in PM2.5.•Anhydrosugars constituted the dominant organic class in PM2.5.•Retene represented >50% of PAHs global mass in PM2.5.
The chapters in this volume present a state of the art of grammaticalization research in the 2010s. They are concerned with the application of new models, such as constructionalization, the ongoing ...debate about the status and modelling of the development of discourse markers, and reveal a renewed interest in the typological application of grammaticalization and in the cognitive motivations for unidirectionality. The contributors consider data from a wide range of languages, including several that have not or marginally been looked at in terms of grammaticalization: Chinese, Dutch, (varieties of) English, French, German, Japanese, Maltese, Old Saxon, Spanish, and languages of the South Caucasian and Zhuang Tai-Kadai families. The chapters range from theoretical discussions to fine-grained analyses of new historical and comparative language data. This volume will be of interest to linguists studying morphosyntactic changes in a range of languages, and in particular to those interested in models for grammatical change.
Unit of Hematology and Clinical Oncology, Centro Regional de Hemodonación, University of Murcia, Spain
Correspondence: Vicente Vicente García, Centro Regional de Hemodonación, Universidad de Murcia, ...C/ Ronda de Garay s/n., 30003 Murcia, Spain. E-mail: vicente.vicente{at}carm.es
Hemostasis and pathological thrombus formation are dynamic processes that require a co-ordinated series of events involving platelet membrane receptors, bidirectional intracellular signals, and release of platelet proteins and inflammatory substances. This review aims to summarize current knowledge in the key steps in the dynamics of thrombus formation, with special emphasis on the crucial participation of platelet receptors and signaling in this process. Initial tethering and firm adhesion of platelets to the exposed subendothelium is mediated by glycoprotein (GP) Ib/IX/V complex and collagen receptors, GP VI and 2 β 1 integrin, in the platelet surface, and by VWF and fibrillar collagen in the vascular site. Interactions between these elements are largely influenced by flow and trigger signaling events that reinforce adhesion and promote platelet activation. Thereafter, soluble agonists, ADP, thrombin, TxA 2 , produced/released at the site of vascular injury act in autocrine and paracrine mode to amplify platelet activation and to recruit circulating platelets to the developing thrombus. Specific interactions of these agonists with their G-protein coupled receptors generate inside-out signaling leading to conformational activation of integrins, in particular IIb β 3 , increasing their ligand affinity. Binding of IIb β 3 to its ligands, mainly fibrinogen, supports processes such as clot retraction and platelet aggregation. Stabilization of thrombi is supported by the late wave of signaling events promoted by close contact between aggregated platelets. The best known contact-dependent signaling is outside-in signaling through Ib β 3 , but new ones are being clarified such as those mediated by interaction of Eph receptors with ephrins, or by Sema 4D and Gas-6 binding to their receptors. Finally, newly identified mechanisms appear to control thrombus growth, including back-shifting of activated integrins and actuation of compensatory molecules such as ESAM or PECAM-1. The expanding knowledge of thrombotic disease is expected to translate into the development of new drugs to help management and prevention of thrombosis.
Key words: platelet, receptors, thrombus formation.
With the Paris Agreement's ambition of limiting climate change to well below 2 °C, negative emission technologies (NETs) have moved into the limelight of discussions in climate science and policy. ...Despite several assessments, the current knowledge on NETs is still diffuse and incomplete, but also growing fast. Here, we synthesize a comprehensive body of NETs literature, using scientometric tools and performing an in-depth assessment of the quantitative and qualitative evidence therein. We clarify the role of NETs in climate change mitigation scenarios, their ethical implications, as well as the challenges involved in bringing the various NETs to the market and scaling them up in time. There are six major findings arising from our assessment: first, keeping warming below 1.5 °C requires the large-scale deployment of NETs, but this dependency can still be kept to a minimum for the 2 °C warming limit. Second, accounting for economic and biophysical limits, we identify relevant potentials for all NETs except ocean fertilization. Third, any single NET is unlikely to sustainably achieve the large NETs deployment observed in many 1.5 °C and 2 °C mitigation scenarios. Yet, portfolios of multiple NETs, each deployed at modest scales, could be invaluable for reaching the climate goals. Fourth, a substantial gap exists between the upscaling and rapid diffusion of NETs implied in scenarios and progress in actual innovation and deployment. If NETs are required at the scales currently discussed, the resulting urgency of implementation is currently neither reflected in science nor policy. Fifth, NETs face severe barriers to implementation and are only weakly incentivized so far. Finally, we identify distinct ethical discourses relevant for NETs, but highlight the need to root them firmly in the available evidence in order to render such discussions relevant in practice.
How do stigmatized political preferences become normalized? I argue that the parliamentary representation of the radical right normalizes radical right support. Radical right politicians breach ...established social norms. Hence their supporters have an incentive to conceal that support. When the radical right enters parliament, however, its voters are likely to perceive that their views have been legitimized, becoming more likely to display their private preferences. I use three studies to test this argument. Study 1 employs a regression discontinuity comparing the underreport of voting for radical right parties (RRPs) above and below thresholds of parliamentary representation. Study 2 compares how much individuals report liking RRPs in post-electoral surveys depending on interview mode. Study 3 employs a difference-in-differences that looks into the underreport of UKIP vote before and after entering parliament. The results support the argument and highlight the role of political institutions in defining the acceptability of behaviors in society.
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