| 1. |
- Laj, Paolo, et al.
(författare)
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A global analysis of climate-relevant aerosol properties retrieved from the network of Global Atmosphere Watch (GAW) near-surface observatories
- 2020
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Ingår i: Atmospheric Measurement Techniques. - : Copernicus GmbH. - 1867-1381 .- 1867-8548. ; 13:8, s. 4353-4392
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Tidskriftsartikel (refereegranskat)abstract
- Aerosol particles are essential constituents of the Earth's atmosphere, impacting the earth radiation balance directly by scattering and absorbing solar radiation, and indirectly by acting as cloud condensation nuclei. In contrast to most greenhouse gases, aerosol particles have short atmospheric residence times, resulting in a highly heterogeneous distribution in space and time. There is a clear need to document this variability at regional scale through observations involving, in particular, the in situ near-surface segment of the atmospheric observation system. This paper will provide the widest effort so far to document variability of climate-relevant in situ aerosol properties (namely wavelength dependent particle light scattering and absorption coefficients, particle number concentration and particle number size distribution) from all sites connected to the Global Atmosphere Watch network. High-quality data from almost 90 stations worldwide have been collected and controlled for quality and are reported for a reference year in 2017, providing a very extended and robust view of the variability of these variables worldwide. The range of variability observed worldwide for light scattering and absorption coefficients, single-scattering albedo, and particle number concentration are presented together with preliminary information on their long-term trends and comparison with model simulation for the different stations. The scope of the present paper is also to provide the necessary suite of information, including data provision procedures, quality control and analysis, data policy, and usage of the ground-based aerosol measurement network. It delivers to users of the World Data Centre on Aerosol, the required confidence in data products in the form of a fully characterized value chain, including uncertainty estimation and requirements for contributing to the global climate monitoring system.
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| 2. |
- Leebens-Mack, James H., et al.
(författare)
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One thousand plant transcriptomes and the phylogenomics of green plants
- 2019
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Ingår i: Nature. - : Nature Publishing Group. - 0028-0836 .- 1476-4687. ; 574:7780, s. 679-
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Tidskriftsartikel (refereegranskat)abstract
- Green plants (Viridiplantae) include around 450,000-500,000 species(1,2) of great diversity and have important roles in terrestrial and aquatic ecosystems. Here, as part of the One Thousand Plant Transcriptomes Initiative, we sequenced the vegetative transcriptomes of 1,124 species that span the diversity of plants in a broad sense (Archaeplastida), including green plants (Viridiplantae), glaucophytes (Glaucophyta) and red algae (Rhodophyta). Our analysis provides a robust phylogenomic framework for examining the evolution of green plants. Most inferred species relationships are well supported across multiple species tree and supermatrix analyses, but discordance among plastid and nuclear gene trees at a few important nodes highlights the complexity of plant genome evolution, including polyploidy, periods of rapid speciation, and extinction. Incomplete sorting of ancestral variation, polyploidization and massive expansions of gene families punctuate the evolutionary history of green plants. Notably, we find that large expansions of gene families preceded the origins of green plants, land plants and vascular plants, whereas whole-genome duplications are inferred to have occurred repeatedly throughout the evolution of flowering plants and ferns. The increasing availability of high-quality plant genome sequences and advances in functional genomics are enabling research on genome evolution across the green tree of life.
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| 3. |
- Augustin, Patrick
(författare)
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Essays on Sovereign Credit Risk and Credit Default Swap Spreads
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This doctoral thesis consists of 4 self-contained chapters: Sovereign Credit Default Swap Premia. This comprehensive review of the literature on sovereign CDS spreads highlights current academic debates and contrasts them with contradictory statements from the popular press. Real Economic Shocks and Sovereign Credit Risk. New empirical evidence highlights that global macroeconomic risk unspanned by global financial risk bears some responsibility for the strong co-movement in sovereign spreads. A model with only two global macroeconomic state variables rationalizes the existence of time-varying risk premia as a compensation for exposure to common U.S. business cycle risk. The Term Structure of CDS Spreads and Sovereign Credit Risk. The term structure of CDS spreads is an informative signal about the relative importance of global and country-specific risk factors for the time variation of sovereign credit spreads. An empirically validated model illustrates how local risk matters relatively more when the slope is negative, while systematic risk bears more responsibility when the slope is positive. Squeezed Everywhere - Disentangling Types of Liquidity and Testing Limits-to-Arbitrage. The CDS-Bond basis is used as a laboratory to disentangle different types of liquidity and to test limits-of-arbitrage. While asset-specific liquidity is cross-correlated in both the cash and derivative market, funding and market liquidity matter only for the former. The tests find strong evidence in favor of margin-based asset pricing and flight-to-quality effects.
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| 4. |
- Augustin, Patrick, et al.
(författare)
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Real economic shocks and sovereign credit risk
- 2013
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- We provide new empirical evidence that unspanned global macroeconomic risk bears some responsibility for the strong co-movement in sovereign spreads. To rationalize these findings, we embed a reduced-form default process into an equilibrium model with downside risk for CDS spreads. Countries differ through their sensitivity to global macroeconomic forecasts and uncertainty. Exploiting the high-frequency information in the CDS term structure across 38 countries, we estimate the model and find parameters consistent with preference for early resolution of uncertainty. Our results confirm the existence of time-varying risk premia in sovereign spreads as a compensation for exposure to common U.S. business cycle risk.
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| 5. |
- Augustin, Patrick
(författare)
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Sovereign credit default swap premia
- 2012
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- This paper provides a comprehensive overview of the young, but rapidly growing literature on sovereign credit default swap premia. It describes key statistical and stylized facts about prices, the market, its players and related trading activities and attempts to raise some thought-provoking questions. We thereby hope to serve as a useful starting point for anyone interested in the topic, with insights for academics, policymakers and practitioners alike.
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| 6. |
- Augustin, Patrick, et al.
(författare)
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Sovereign Credit Risk and Corporate Borrowing Costs
- 2014
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- We show that an increase in sovereign credit risk leads to higher corporate borrowing costs. This is demonstrated using the announcement of the first Greek bailout on April 11, 2010 that triggered a significant increase, rather than the expected decrease, in Greece's borrowing costs. The event represents an unexpected shift in the perception of sovereign risk across Europe. We estimate that a one percent increase in sovereign credit risk raises corporate borrowing costs by 0.1 percent after the bailout, reflecting a higher dependence between sovereign and corporate credit risk. Further results suggest more pronounced effects in countries that belong to the Eurozone, that are more financially distressed and that have weaker property rights. We also find that borrowing costs rise at least as much for non-financial companies as for financial companies. Non-financial companies that are more bank dependent and that have greater public ownership are relatively more affected by increased sovereign credit risk.
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| 7. |
- Augustin, Patrick
(författare)
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Squeezed everywhere - disentangling types of liquidity and testing limits-to-arbitrage
- 2013
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- I disentangle asset-specific, market-wide and funding liquidity in the CDS-Bond basis outside and during the 07/09 financial crisis, stressing the importance of separating different types of liquidity. While asset-specific liquidity is cross-correlated in both the cash and derivative market, funding and market liquidity matter only for the former. Using different types of liquidity, I test several theoretical predictions of limits-to-arbitrage. I find strong evidence in favor of margin-based asset pricing and flight-to-quality effects. In addition, both asset-specific and funding liquidity are mutually reinforcing with market-wide liquidity, while there is little commonality between firm-specific and funding liquidity.
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| 8. |
- Augustin, Patrick
(författare)
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The term structure of CDS spreads and sovereign credit risk
- 2013
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- I study the term structure of credit default swap spreads to understand how global and country-specific risk factors explain time variation in sovereign credit risk. The shape of the term structure conveys significant information about the relative importance of global and domestic risk. Global shocks determine spread changes when the slope is positive. Nonetheless, a negative slope indicates that domestic shocks are relatively more important. To draw these conclusions, I develop a recursive preference-based model with long-run risk for credit default swaps. The underlying default process, which modulates expectations about future default probabilities, depends both on global macroeconomic uncertainty and country-specific risk. Their dynamics and investor preferences jointly explain time variation in the term structure. I evaluate the model using a panel of 44 countries. County-specific fundamentals explain relatively more spread variation than global factors as countries become more distressed. The number of months the term structure is inverted proxies for the duration of distress. Overall, the results suggest that both sources of risk are important. They simply matter in different times.
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| 9. |
- Flechard, Chris R., et al.
(författare)
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Carbon-nitrogen interactions in European forests and semi-natural vegetation - Part 1: Fluxes and budgets of carbon, nitrogen and greenhouse gases from ecosystem monitoring and modelling
- 2020
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Ingår i: Biogeosciences. - : Copernicus GmbH. - 1726-4170 .- 1726-4189. ; 17:6, s. 1583-1620
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Tidskriftsartikel (refereegranskat)abstract
- The impact of atmospheric reactive nitrogen (N-r) deposition on carbon (C) sequestration in soils and biomass of unfertilized, natural, semi-natural and forest ecosystems has been much debated. Many previous results of this dC/dN response were based on changes in carbon stocks from periodical soil and ecosystem inventories, associated with estimates of N-r deposition obtained from large-scale chemical transport models. This study and a companion paper (Flechard et al., 2020) strive to reduce uncertainties of N effects on C sequestration by linking multi-annual gross and net ecosystem productivity estimates from 40 eddy covariance flux towers across Europe to local measurement-based estimates of dry and wet N-r deposition from a dedicated collocated monitoring network. To identify possible ecological drivers and processes affecting the interplay between C and N-r inputs and losses, these data were also combined with in situ flux measurements of NO, N2O and CH4 fluxes; soil NO3- leaching sampling; and results of soil incubation experiments for N and greenhouse gas (GHG) emissions, as well as surveys of available data from online databases and from the literature, together with forest ecosystem (BAS-FOR) modelling. Multi-year averages of net ecosystem productivity (NEP) in forests ranged from -70 to 826 gCm(-2) yr(-1) at total wet + dry inorganic N-r deposition rates (N-dep) of 0.3 to 4.3 gNm(-2) yr(-1) and from -4 to 361 g Cm-2 yr(-1) at N-dep rates of 0.1 to 3.1 gNm(-2) yr(-1) in short semi-natural vegetation (moorlands, wetlands and unfertilized extensively managed grasslands). The GHG budgets of the forests were strongly dominated by CO2 exchange, while CH4 and N2O exchange comprised a larger proportion of the GHG balance in short semi-natural vegetation. Uncertainties in elemental budgets were much larger for nitrogen than carbon, especially at sites with elevated N-dep where N-r leaching losses were also very large, and compounded by the lack of reliable data on organic nitrogen and N-2 losses by denitrification. Nitrogen losses in the form of NO, N2O and especially NO3- were on average 27%(range 6 %-54 %) of N-dep at sites with N-dep < 1 gNm(-2) yr(-1) versus 65% (range 35 %-85 %) for N-dep > 3 gNm(-2) yr(-1). Such large levels of N-r loss likely indicate that different stages of N saturation occurred at a number of sites. The joint analysis of the C and N budgets provided further hints that N saturation could be detected in altered patterns of forest growth. Net ecosystem productivity increased with N-r deposition up to 2-2.5 gNm(-2) yr(-1), with large scatter associated with a wide range in carbon sequestration efficiency (CSE, defined as the NEP/GPP ratio). At elevated N-dep levels (> 2.5 gNm(-2) yr(-1)), where inorganic N-r losses were also increasingly large, NEP levelled off and then decreased. The apparent increase in NEP at low to intermediate N-dep levels was partly the result of geographical cross-correlations between N-dep and climate, indicating that the actual mean dC/dN response at individual sites was significantly lower than would be suggested by a simple, straightforward regression of NEP vs. N-dep.
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| 10. |
- Sartelli, Massimo, et al.
(författare)
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Ten golden rules for optimal antibiotic use in hospital settings: the WARNING call to action
- 2023
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Ingår i: WORLD JOURNAL OF EMERGENCY SURGERY. - 1749-7922. ; 18:1
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Forskningsöversikt (refereegranskat)abstract
- Antibiotics are recognized widely for their benefits when used appropriately. However, they are often used inappropriately despite the importance of responsible use within good clinical practice. Effective antibiotic treatment is an essential component of universal healthcare, and it is a global responsibility to ensure appropriate use. Currently, pharmaceutical companies have little incentive to develop new antibiotics due to scientific, regulatory, and financial barriers, further emphasizing the importance of appropriate antibiotic use. To address this issue, the Global Alliance for Infections in Surgery established an international multidisciplinary task force of 295 experts from 115 countries with different backgrounds. The task force developed a position statement called WARNING (Worldwide Antimicrobial Resistance National/International Network Group) aimed at raising awareness of antimicrobial resistance and improving antibiotic prescribing practices worldwide. The statement outlined is 10 axioms, or "golden rules," for the appropriate use of antibiotics that all healthcare workers should consistently adhere in clinical practice.
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