1,176 research outputs found
High-resolution impurity data from the GRIP ice core
No full textThe ice core was drilled during the GRIP project in 1989-1992 at the Summit of the Greenland ice sheet. The length is 3025 m. Present-day accumulation 0.23 m ice/yr. Position 72.57N 37.62W, 3232 m a.s.l.. Impurities were measures as described in Fuhrer et al. (1993). The Holocene data were used for annual-layer identification during the making of the GICC05 and GIC21 time scales, but data are also provided over GS-1 (roughly equivalent to the Younger Dryas) and GI-1 (roughly equivalent to the Bølling-Allerød period). Data from deeper sections exist. Corresponding data author: Hubertus Fischer, Climate and Environmental Physics, Physics Institute, and Oeschger Centre for Climate Change Research, University of Bern, [email protected]
2019 European Thyroid Association Guidelines for the Treatment and Follow-Up of Advanced Radioiodine-Refractory Thyroid Cancer
No full textThe vast majority of thyroid cancers of follicular origin (TC) have a very favourable outcome, but 5-10% of cases will develop metastatic disease. Around 60-70% of this subset, hence less than 5% of all patients with TC, will become radioiodine refractory (RAI-R), with a significant negative impact on prognosis and a mean life expectancy of 3-5 years. Since no European expert consensus or guidance for this challenging condition is currently available, a task force of TC experts was nominated by the European Thyroid Association (ETA) to prepare this document based on the principles of clinical evidence. The task force started to work in September 2018 and after several revision rounds, prepared a list of recommendations to support the treatment and follow-up of patients with advanced TC. Criteria for advanced RAI-R TC were proposed, and the most appropriate diagnostic tools and the local, systemic and palliative treatments are described. Systemic therapy with multikinase inhibitors is fully discussed, including recommendations on how to start it and at which dosage, on the duration of treatment, and on the management of side effects. The appropriate relationship between the specialist and the patient/family as well as ethical issues are covered. Based on the available studies and on personal experience, the experts provided 39 recommendations aimed to improve the management of advanced RAI-R TCs. Above all of them is the indication to treat and follow these patients in a specialized setting which allows the interaction between several specialists in a multidisciplinary team
Cusps in K(L) 3pi decays
No full textAbstractThe pion mass difference generates a pronounced cusp in K→3π decays, the strength of which is related to the ππ S-wave scattering lengths. We apply an effective field theory framework developed earlier to evaluate the amplitudes for KL→3π decays in a systematic manner, where the strictures imposed by analyticity and unitarity are respected automatically. The amplitudes for the decay η→3π are also given
Alpine grassland soils contain large proportion of labile carbon but indicate long turnover times
No full textAlpine soils are expected to contain large amounts of labile carbon (C) which may become a further source of atmospheric carbon dioxide (CO2) as a result of global warming. However, there is little data available on these soils, and understanding of the influence of environmental factors on soil organic matter (SOM) turnover is limited. We extracted 30 cm deep cores from five grassland sites along a small elevation gradient from 2285 to 2653 m a.s.l. in the central Swiss Alps. Our aim was to determine the quantity, allocation, degree of stabilization and mean residence time (MRT) of SOM in relation to site factors such as soil pH, vegetation, and SOM composition. Soil fractions obtained by size and density fractionation revealed a high proportion of labile C in SOM, mostly in the uppermost soil layers. Labile C in the top 20 cm across the gradient ranged from 39.6–57.6 % in comparison to 7.2–29.6 % reported in previous studies for lower elevation soils (810–1960 m a.s.l.). At the highest elevation, MRTs measured by means of radiocarbon dating and turnover modelling, increased between fractions of growing stability from 90 years in free POM (fPOM) to 534 years in the mineral associated fraction (mOM). Depending on elevation and pH, plant community data suggested considerable variation in the quantity and quality of organic matter input, and these patterns could be reflected in the dynamics of soil C. 13C NMR data confirmed a relationship of SOM composition to MRT. While low temperature in alpine environments is likely to be a major cause for the slow turnover rate observed, other factors such as residue quality and soil pH, as well as the combination of all factors, play an important role in causing small scale variability of SOM turnover. Failing to incorporate this interplay of controlling factors into models may impair the performance of models to project SOM responses to environmental change
A Record of Atmospheric Oxidant from Polar Ice Cores over the Past 100,000 Years: Dream or Real Possibility?
No full textThe principal oxidants of the earth’s atmosphere are O3, OH radical and H2O2. The total atmospheric burden of these three species determines the oxidation capacity of the atmosphere [Thompson, 1992]. Each of these species reacts with different atmospheric trace constituents, and determines their atmospheric lifetimes. In particular, the OH radical reacts very fast with almost all naturally and anthropogenically emitted species; therefore, this radical has the nickname “tropospheric vacuum cleaner” [Graedel, 1978]
Dynamics of direct X-ray detection processes in high-Z Bi<sub>2</sub>O<sub>3</sub> nanoparticles-loaded PFO polymer-based diodes
No full textSemiconducting polymer based X-ray detectors doped with high-Z nanoparticles hold the promise to combine mechanical flexibility and large-area processing with a high X-ray stopping power and sensitivity. Currently, a lack of understanding of how nanoparticle doping impacts the detector dynamics impedes the optimization of such detectors. Here, we study direct X-ray radiation detectors based on the semiconducting polymer poly(9,9-dioctyfluorene) blended with Bismuth(III)oxide (Bi2O3) nanoparticles (NPs). Pure polymer diodes show a high mobility of 1.3 × 10-5 cm2/V s, a low leakage current of 200 nA/cm2 at -80 V, and a high rectifying factor up to 3 × 105 that allow us to compare the X-ray response of a polymer detector in charge-injection conditions (forward bias) and in charge-collection conditions (reverse bias), together with the impact of NP-loading in the two operation regimes. When operated in reverse bias, the detectors reach the state of the art sensitivity of 24 μC/Gy cm2, providing a fast photoresponse. In forward operation, a slower detection dynamics but improved sensitivity (up to 450 ± 150 nC/Gy) due to conductive gain is observed. High-Z NP doping increases the X-ray absorption, but higher NP loadings lead to a strong reduction of charge-carrier injection and transport due to a strong impact on the semiconductor morphology. Finally, the time response of optimized detectors showed a cut-off frequency up to 200 Hz. Taking advantage of such a fast dynamic response, we demonstrate an X-ray based velocity tracking system.Novel Aerospace Material
Intrinsic and Inherited Inflation Persistence
No full textIn the conventional view of inflation, the New Keynesian Phillips curve (NKPC) captures most of the persistence in inflation. The sources of persistence are twofold. First, the "driving process" for inflation is quite persistent, and the NKPC implies that inflation must "inherit" this persistence. Second, backward-looking or indexing behavior imparts some "intrinsic" persistence to inflation. This paper shows that, in practice, inflation in the NKPC inherits very little of the persistence of the driving process, and it is intrinsic persistence that constitutes the dominant source of persistence. The reasons are that, first, the coefficient on the driving process is small, and, second, the shock that disturbs the NKPC is large.
Endocytosis of the ASGP receptor H1 is reduced by mutation of tyrosine-5 but still occurs via coated pits
No full textThe clustering of plasma membrane receptors in clathrin-coated pits depends on determinants within their cytoplasmic domains. In several cases, individual tyrosine residues were shown to be necessary for rapid internalization. We have mutated the single tyrosine at position 5 in the cytoplasmic domain of the major subunit H1 of the asialoglycoprotein receptor to alanine. Expressed in fibroblasts cells, the mutant protein was accumulated in the plasma membrane, and its rate of internalization was reduced by a factor of four. The residual rate of endocytosis, however, was still significantly higher than that of resident plasma membrane proteins. Upon acidification of the cytoplasm, which specifically inhibits the formation of clathrin-coated vesicles but not uptake of the fluid phase marker Lucifer yellow, residual endocytosis was blocked. By immunoelectron microscopy mutant H1 could be directly demonstrated in coated pits. The fraction of wild-type and mutant H1 present in coated pits as determined by immunogold localization correlated well with the respective rates of internalization. Thus, mutation of tyrosine-5 only partially inactivates recognition of H1 for incorporation into coated pits
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