924 research outputs found
Comparison of Proxy and Multimodel Ensemble Means
Proxyâmodel comparisons show large discrepancies in the impact of volcanic aerosols on the hydrology of the Asian monsoon region (AMR). This was mostly imputed to uncertainties arising from the use of a single model in previous studies. Here we compare two groups of CMIP5 multimodel ensemble mean (MMEM) with the treeâringâbased reconstruction Monsoon Asia Drought Atlas (MADA PDSI), to examine their reliability in reproducing the hydrological effects of the volcanic eruptions in 1300â1850 CE. Time series plots indicate that the MADA PDSI and the MMEMs agree on the significant drying effect of volcanic perturbation over the monsoonâdominated subregion, while disparities exist over the westerliesâdominated subregion. Comparisons of the spatial patterns suggest that the MADA PDSI and the MMEMs show better agreement 1 year after the volcanic eruption than in the eruption year and in subregions where more treeâring chronologies are available. The MADA PDSI and the CMIP5 MMEMs agree on the drying effect of volcanic eruptions in westernâEast Asia, South Asian summer monsoon, and northern East Asian summer monsoon (EASM) regions. Model results suggest significant wetting effect in southern EASM and westernâSouth Asia, which agrees with the observed hydrological response to the 1991 Mount Pinatubo eruption. Analysis on model output from the Last Millennium Ensemble project shows similar hydrological responses. These results suggest that the CMIP5 MMEM is able to reproduce the impact of volcanic eruptions on the hydrology of the southern AMR
Development of a thermal ionizer as ion catcher
An effective ion catcher is an important part of a radioactive beam facility
that is based on in-flight production. The catcher stops fast radioactive
products and emits them as singly charged slow ions. Current ion catchers are
based on stopping in He and H gas. However, with increasing intensity of
the secondary beam the amount of ion-electron pairs created eventually prevents
the electromagnetic extraction of the radioactive ions from the gas cell. In
contrast, such limitations are not present in thermal ionizers used with the
ISOL production technique. Therefore, at least for alkaline and alkaline earth
elements, a thermal ionizer should then be preferred. An important use of the
TRIP facility will be for precision measurements using atom traps. Atom
trapping is particularly possible for alkaline and alkaline earth isotopes. The
facility can produce up to 10 s of various Na isotopes with the
in-flight method. Therefore, we have built and tested a thermal ionizer. An
overview of the operation, design, construction, and commissioning of the
thermal ionizer for TRIP will be presented along with first results for
Na and Na.Comment: 10 pages, 4 figures, XVth International Conference on Electromagnetic
Isotope Separators and Techniques Related to their Applications (EMIS 2007
Evidence for a Kondo destroying quantum critical point in YbRh2Si2
The heavy-fermion metal YbRhSi is a weak antiferromagnet below
K. Application of a low magnetic field T () is sufficient to continuously suppress the antiferromagnetic (AF) order.
Below K, the Sommerfeld coefficient of the electronic specific
heat exhibits a logarithmic divergence. At K, (), while the electrical resistivity
(: residual resistivity). Upon
extrapolating finite- data of transport and thermodynamic quantities to , one observes (i) a vanishing of the "Fermi surface crossover" scale
, (ii) an abrupt jump of the initial Hall coefficient and
(iii) a violation of the Wiedemann Franz law at , the field-induced
quantum critical point (QCP). These observations are interpreted as evidence of
a critical destruction of the heavy quasiparticles, i.e., propagating Kondo
singlets, at the QCP of this material.Comment: 20 pages, 8 figures, SCES 201
Challenges and Opportunities for Spark Plasma Sintering: A Key Technology for a New Generation of Materials
This is an open access article distributed under the terms of the Creative Commons Attribution License.-- et al.Peer reviewe
Risk factors associated with beef cattle losses on intensive fattening farms in Austria, Germany and Italy
Computational protein profile similarity screening for quantitative mass spectrometry experiments
Motivation: The qualitative and quantitative characterization of protein abundance profiles over a series of time points or a set of environmental conditions is becoming increasingly important. Using isobaric mass tagging experiments, mass spectrometry-based quantitative proteomics deliver accurate peptide abundance profiles for relative quantitation. Associated data analysis workflows need to provide tailored statistical treatment that (i) takes the correlation structure of the normalized peptide abundance profiles into account and (ii) allows inference of protein-level similarity. We introduce a suitable distance measure for relative abundance profiles, derive a statistical test for equality and propose a protein-level representation of peptide-level measurements. This yields a workflow that delivers a similarity ranking of protein abundance profiles with respect to a defined reference. All procedures have in common that they operate based on the true correlation structure that underlies the measurements. This optimizes power and delivers more intuitive and efficient results than existing methods that do not take these circumstances into account. Results: We use protein profile similarity screening to identify candidate proteins whose abundances are post-transcriptionally controlled by the Anaphase Promoting Complex/Cyclosome (APC/C), a specific E3 ubiquitin ligase that is a master regulator of the cell cycle. Results are compared with an established protein correlation profiling method. The proposed procedure yields a 50.9-fold enrichment of co-regulated protein candidates and a 2.5-fold improvement over the previous method
Epistemic policy networks in the European Unionâs CBRN risk mitigation policy
This paper offers insights into an innovative and currently flagship approach of the European Union (EU) to the mitigation of chemical, biological, radiological, and nuclear (CBRN) risks. Building on its long-time experience in the CBRN field, the EU has incorporated methods familiar to the students of international security governance: it is establishing regional networks of experts and expertise. CBRN Centers of Excellence, as they are officially called, aim to contribute to the security and safety culture in different parts of Africa, the Middle East, South East Asia, and South East Europe, in the broadly construed CBRN area. These regional networks represent a modern form of security cooperation, which can be conceptualized as an epistemic policy networks approach. It offers flexibility to the participating states, which have different incentives to get involved. At the same, however, the paper identifies potential limitations and challenges of epistemic policy networks in this form
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