80 research outputs found
Theory of Diversification and Cross-subsidy for Eurobonds
In the face of excessive yield spreads on sovereign bonds in the European Monetary Union, the issuance of joint debt commonly known as Eurobonds has been proposed to ease the access to credit for fiscally struggling countries. This paper is the first to consider Eurobonds in terms of diversification and cross-subsidy benefits. It shows that the risk-sharing nature of Eurobonds lowers sovereign default probability in a non-replicable way for investors thereby lowering investment losses on a macro-level. Countries benefit as well from lower default probability that prevents sovereign bankruptcy costs. On a micro-level, fiscally strong countries have to weigh the benefits of Eurobonds against the two-fold costs of higher interest payments and financial support for defaulting countries. With further research, the argument brought forward in this paper will contribute to a more comprehensive debate about the benefits and costs of Eurobonds
Nitrogen sources and net growth efficiency of zooplankton in three Amazon River plume food webs
The plasticity of nitrogen specific net growth efficiency (NGE) in marine mesozooplankton is currently unresolved, with discordant lines of evidence suggesting that NGE is constant, or that it varies with nitrogen source, food availability, and food quality in marine ecosystems. Specifically, the fate of nitrogen from nitrogen fixation is poorly known. We use 15N : 14N ratios in plankton in combination with hydrological data, nutrient profiles, and nitrogen fixation rate measurements to investigate the relationship between new nitrogen sources and the nitrogen specific NGE in three plankton communities along the outer Amazon River plume. The NGE of small (200–500 μm) mesozooplankton was estimated from the δ 15N differences between particulate nitrogen and zooplankton using an open system Rayleigh fractionation model. The transfer efficiency of nitrogen among larger (\u3e 500 μm) mesozooplankton was estimated from the change in δ 15N as a function of zooplankton size. The Amazon River was not a significant source of bioavailable nitrogen anywhere in our study region, and subsurface nitrate was the primary new nitrogen source for the outer shelf community, which was dominated by diatoms. N2 fixation was the principal new nitrogen source at sites of high diatom diazotroph association abundance and at oceanic sites dominated by Trichodesmium spp. and Synechococcus spp. Although we found clear spatial differences in food quantity, food quality, and diazotroph inputs into mesozooplankton, our data show no significant differences in mesozooplankton nitrogen transfer efficiency and NGE (for latter, mean ± SD: 59 ± 10%) among sites
Do NO, N2O, N2 and N2 fluxes differ in soils sourced from cropland and varying riparian buffer vegetation? An incubation study
Riparian buffers are expedient interventions for water quality functions in agricultural landscapes. However, the choice of vegetation and management affects soil microbial communities, which in turn affect nutrient cycling and the production and emission of gases such as nitric oxide (NO), nitrous oxide (N2O), nitrogen gas (N2) and carbon dioxide (CO2). To investigate the potential fluxes of the above-mentioned gases, soil samples were collected from a cropland and downslope grass, willow and woodland riparian buffers from a replicated plot scale experimental facility. The soils were re-packed into cores and to investigate their potential to produce the aforementioned gases via potential denitrification, a potassium nitrate (KNO3−) and glucose (labile carbon)-containing amendment, was added prior to incubation in a specialized laboratory DENItrification System (DENIS). The resulting NO, N2O, N2 and CO2 emissions were measured simultaneously, with the most NO (2.9 ± 0.31 mg NO m−2) and N2O (1413.4 ± 448.3 mg N2O m−2) generated by the grass riparian buffer and the most N2 (698.1 ± 270.3 mg N2 m−2) and CO2 (27,558.3 ± 128.9 mg CO2 m−2) produced by the willow riparian buffer. Thus, the results show that grass riparian buffer soils have a greater NO3− removal capacity, evidenced by their large potential denitrification rates, while the willow riparian buffers may be an effective riparian buffer as its soils potentially promote complete denitrification to N2, especially in areas with similar conditions to the current study
Riparian buffer strips influence nitrogen losses as nitrous oxide and leached N from upslope permanent pasture
Riparian buffer strips can have a significant role in reducing nitrogen (N) transfers from agricultural land to freshwater primarily via denitrification and plant uptake processes, but an unintended trade-off can be elevated nitrous oxide (N2O) production rates. Against this context, our replicated bounded plot scale study investigated N2O emissions from un-grazed ryegrass pasture served by three types of riparian buffer strips with different vegetation, comprising: (i) grass riparian buffer with novel deep-rooting species, (ii) willow (young trees at establishment phase) riparian buffer, and (iii) deciduous woodland (also young trees at establishment phase) riparian buffer. The experimental control was ryegrass pasture with no buffer strip. N2O emissions were measured at the same time as total oxidized N in run-off, and soil and environmental characteristics in the ri parian buffer strips and upslope pasture between 2018 and 2019. During most of the sampling days, the no-buffer control treatment showed significantly (P < 0.05) greater N2O fluxes and cumulative N2O emissions compared to the remainder of the treatments. Our results also showed that the grass riparian buffer strip is a sink of N2O equivalent to − 2310.2 g N2O-N ha− 1 day− 1 (95% confidence interval:− 535.5 to 492). Event-based water quality results obtained during storms (12 November 2018 and 11 February 2019) showed that the willow riparian buffer treatment had the highest flow-weighted mean N concentrations (N-FWMC) of 0.041 ± 0.022 and 0.031
± 0.015 mg N L− 1, when compared to the other treatments. Our 9-month experiment therefore, shows that ri parian buffer strips with novel deep-rooting grass can therefore potentially address emissions to both water and air. The results imply that over a shorter timeline similar to the current study, the grass riparian buffer strip can potentially address N emission to both air and water, particularly when serving a permanent pasture in similar settings as the current experiment.Fil: Dlamini, J.C. Crop and Climate Sciences. Departament of Soil; Sudáfrica. Rothamsted Research. Sustainable Agriculture Sciences; Reino Unido. University of Pretoria. Department of Plant and Soil Sciences; SudáfricaFil: Cardenas, L.M. Rothamsted Research. Sustainable Agriculture Sciences; Reino Unido.Fil: Tesfamarian, E.H. University of Pretoria. Department of Plant and Soil Sciences; SudáfricaFil: Dunn, R.M. Rothamsted Research. Sustainable Agriculture Sciences; Reino Unido.Fil: Loick, N. Rothamsted Research. Sustainable Agriculture Sciences; Reino Unido.Fil: Charteris, A.F. Rothamsted Research. Sustainable Agriculture Sciences; Reino Unido.Fil: Cocciaglia, L. Università degli Studi di Perugia. Dipartimento di Scienze Agrarie, Alimentari e Ambientali; ItaliaFil: Vangeli, Sebastián. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Clima y Agua; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Ingeniería Agrícola y Uso de la Tierra. Cátedra de Manejo y Conservación de Suelo; ArgentinaFil: Blackwell, M.S.A. Rothamsted Research. Sustainable Agriculture Sciences; Reino Unido.Fil: Upadhayay, H.R. Rothamsted Research. Sustainable Agriculture Sciences; Reino Unido.Fil: Hawkins, J.M.B. Rothamsted Research. Sustainable Agriculture Sciences; Reino Unido.Fil: Evans, J. Rothamsted Research. Computational and Analytical Sciences; Reino UnidoFil: Collins, A.L. Rothamsted Research. Sustainable Agriculture Sciences; Reino Unido
REALMS: Resilient exploration and lunar mapping system.
peer reviewedSpace resource utilisation is opening a new space era. The scientific proof of the presence of water ice on the south pole of the Moon, the recent advances in oxygen extraction from lunar regolith, and its use as a material to build shelters are positioning the Moon, again, at the centre of important space programs. These worldwide programs, led by ARTEMIS, expect robotics to be the disrupting technology enabling humankind's next giant leap. However, Moon robots require a high level of autonomy to perform lunar exploration tasks more efficiently without being constantly controlled from Earth. Furthermore, having more than one robotic system will increase the resilience and robustness of the global system, improving its success rate, as well as providing additional redundancy. This paper introduces the Resilient Exploration and Lunar Mapping System, developed with a scalable architecture for semi-autonomous lunar mapping. It leverages Visual Simultaneous Localization and Mapping techniques on multiple rovers to map large lunar environments. Several resilience mechanisms are implemented, such as two-agent redundancy, delay invariant communications, a multi-master architecture different control modes. This study presents the experimental results of REALMS with two robots and its potential to be scaled to a larger number of robots, increasing the map coverage and system redundancy. The system's performance is verified and validated in a lunar analogue facility, and a larger lunar environment during the European Space Agency (ESA)-European Space Resources Innovation Centre Space Resources Challenge. The results of the different experiments show the efficiency of REALMS and the benefits of using semi-autonomous systems
CO2 fluxes from three different temperate grazed pastures using Eddy covariance measurements
Grasslands cover around 25% of the global ice-free land surface, they are used predominantly for forage and livestock production and are considered to contribute significantly to soil carbon (C) sequestration. Recent investigations into using ‘nature-based solutions’ to limit warming to <2 °C suggest up to 25% of GHG mitigation might be achieved through changes to grassland management. In this study we evaluate pasture management interventions at the Rothamsted Research North Wyke Farm Platform, under commercial farming conditions, over two years and consider their impacts on net CO2 exchange. We investigate if our permanent pasture system (PP) is, in the short-term, a net sink for CO2 and whether reseeding this with deep-rooting, high-sugar grass (HS) or a mix of high-sugar grass and clover (HSC) might increase the net removal of atmospheric CO2. In general CO2 fluxes were less variable in 2018 than in 2017 while overall we found that net CO2 fluxes for the PP treatment changed from a sink in 2017 (−5.40 t CO2 ha−1 y−1) to a source in 2018 (6.17 t CO2 ha−1 y−1), resulting in an overall small source of 0.76 t CO2 ha−1 over the two years for this treatment. HS showed a similar trend, changing from a net sink in 2017 (−4.82 t CO2 ha−1 y−1) to a net source in 2018 (3.91 t CO2 ha−1 y−1) whilst the HSC field was a net source in both years (3.92 and 4.10 t CO2 ha−1 y−1, respectively). These results suggested that pasture type has an influence in the atmospheric CO2 balance and our regression modelling supported this conclusion, with pasture type and time of the year (and their interaction) being significant factors in predicting fluxes
Controls on zooplankton methane production in the central Baltic Sea
Several methanogenic
pathways in oxic surface waters were recently discovered, but their relevance
in the natural environment is still unknown. Our study examines distinct
methane (CH4) enrichments that repeatedly occur below the thermocline during the
summer months in the central Baltic Sea. In agreement with previous studies
in this region, we discovered differences in the methane distributions
between the western and eastern Gotland Basin, pointing to in situ methane
production below the thermocline in the latter (concentration of CH4 14.1±6.1 nM, δ13C CH4 −62.9 ‰). Through
the use of a high-resolution hydrographic model of the Baltic Sea, we showed
that methane below the thermocline can be transported by upwelling events
towards the sea surface, thus contributing to the methane flux at the
sea–air interface. To quantify zooplankton-associated methane production
rates, we developed a sea-going methane stripping-oxidation line to determine
methane release rates from copepods grazing on 14C-labelled
phytoplankton. We found that (1) methane production increased with the number
of copepods, (2) higher methane production rates were measured in incubations
with Temora longicornis (125±49 fmol methane copepod−1 d−1) than in incubations with
Acartia spp. (84±19 fmol CH4 copepod−1 d−1) dominated zooplankton
communities, and (3) methane was only produced on a Rhodomonas sp.
diet, and not on a cyanobacteria diet. Furthermore, copepod-specific methane
production rates increased with incubation time. The latter finding suggests
that methanogenic substrates for water-dwelling microbes are released by cell
disruption during feeding, defecation, or diffusion from fecal pellets. In
the field, particularly high methane concentrations coincided with stations
showing a high abundance of DMSP/DMSO-rich Dinophyceae. Lipid biomarkers extracted
from phytoplankton- and copepod-rich samples revealed that Dinophyceae are a
major food source of the T. longicornis dominated zooplankton
community, supporting the proposed link between copepod grazing, DMSP/DMSO
release, and the build-up of subthermocline methane enrichments in the
central Baltic Sea.</p
Wait Up!: Attachment and Sovereign Power.
Sociologists and feminist scholars have, over many decades, characterised attachment as a social construction that functions to support political and gender conservatism. We accept that attachment theory has seen use to these ends and consider recent deployments of attachment theory as justification for a minimal State within conservative political discourse in the UK since 2009. However, we contest that attachment is reducible to its discursive construction. We consider Judith Butler's depiction of the infant attached to an abusive caregiver as a foundation and parallel to the position of the adult citizen subjected to punitive cultural norms and political institutions. We develop and qualify Butler's account, drawing on the insights offered by the work of Lauren Berlant. We also return to Foucault's Psychiatric Power lectures, in which familial relations are situated as an island of sovereign power within the sea of modern disciplinary institutions. These reflections help advance analysis of three important issues: the social and political implications of attachment research; the relationship between disciplinary and sovereign power in the affective dynamic of subjection; and the political and ethical status of professional activity within the psy disciplines.This is the final version of the article. It first appeared from Springer via http://dx.doi.org/10.1007/s10767-014-9192-
Incidence of epidural haematoma and neurological injury in cardiovascular patients with epidural analgesia/anaesthesia: systematic review and meta-analysis
BACKGROUND: Epidural anaesthesia is used extensively for cardiothoracic and vascular surgery in some centres, but not in others, with argument over the safety of the technique in patients who are usually extensively anticoagulated before, during, and after surgery. The principle concern is bleeding in the epidural space, leading to transient or persistent neurological problems. METHODS: We performed an extensive systematic review to find published cohorts of use of epidural catheters during vascular, cardiac, and thoracic surgery, using electronic searching, hand searching, and reference lists of retrieved articles. RESULTS: Twelve studies included 14,105 patients, of whom 5,026 (36%) had vascular surgery, 4,971 (35%) cardiac surgery, and 4,108 (29%) thoracic surgery. There were no cases of epidural haematoma, giving maximum risks following epidural anaesthesia in cardiac, thoracic, and vascular surgery of 1 in 1,700, 1 in 1,400 and 1 in 1,700 respectively. In all these surgery types combined the maximum expected rate would be 1 in 4,700. In all these patients combined there were eight cases of transient neurological injury, a rate of 1 in 1,700 (95% confidence interval 1 in 3,300 to 1 in 850). There were no cases of persistent neurological injury (maximum expected rate 1 in 4,600). CONCLUSION: These estimates for cardiothoracic epidural anaesthesia should be the worst case. Limitations are inadequate denominators for different types of surgery in anticoagulated cardiothoracic or vascular patients more at risk of bleeding
Methods of estimation of mitral valve regurgitation for the cardiac surgeon
Mitral valve regurgitation is a relatively common and important heart valve lesion in clinical practice and adequate assessment is fundamental to decision on management, repair or replacement. Disease localised to the posterior mitral valve leaflet or focal involvement of the anterior mitral valve leaflet is most amenable to mitral valve repair, whereas patients with extensive involvement of the anterior leaflet or incomplete closure of the valve are more suitable for valve replacement. Echocardiography is the recognized investigation of choice for heart valve disease evaluation and assessment. However, the technique is depended on operator experience and on patient's hemodynamic profile, and may not always give optimal diagnostic views of mitral valve dysfunction. Cardiac catheterization is related to common complications of an interventional procedure and needs a hemodynamic laboratory. Cardiac magnetic resonance (MRI) seems to be a useful tool which gives details about mitral valve anatomy, precise point of valve damage, as well as the quantity of regurgitation. Finally, despite of its higher cost, cardiac MRI using cine images with optimized spatial and temporal resolution can also resolve mitral valve leaflet structural motion, and can reliably estimate the grade of regurgitation
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