73 research outputs found
Emission-Induced Nonlinearities in the Global Aerosol System: Results from the ECHAM5-HAM Aerosol-Climate Model
In a series of simulations with the global ECHAM5-HAM aerosol-climate model, the response to changes in anthropogenic emissions is analyzed. Traditionally, additivity is assumed in the assessment of the aerosol climate impact, as the underlying bulk aerosol models are largely constrained to linearity. The microphysical aerosol module HAM establishes degrees of freedom for nonlinear responses of the aerosol system. In this study’s results, aerosol column mass burdens respond nonlinearly to changes in anthropogenic emissions, manifested in alterations of the aerosol lifetimes. Specific emission changes induce modifications of aerosol cycles with unaltered emissions, indicating a microphysical coupling of the aerosol cycles. Anthropogenic carbonaceous emissions disproportionately contribute to the accumulation mode numbers close to the source regions. In contrast, anthropogenic sulfuric emissions less than proportionally contribute to the accumulation mode numbers close to the source regions and disproportionately contribute in remote regions. The additivity of the aerosol system is analyzed by comparing the changes from a simulation with emission changes for several compounds with the sum of changes of single simulations, in each of which one of the emission changes was introduced. Close to the anthropogenic source regions, deviations from additivity are found at up to 30% and 15% for the accumulation mode number burden and aerosol optical thickness, respectively. These results challenge the traditional approach of assessing the climate impact of aerosols separately for each component and demand for integrated assessments and emission strategies
The Mammalian Circadian Timing System: Organization and Coordination of Central and Peripheral Clocks
Large expert-curated database for benchmarking document similarity detection in biomedical literature search
Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe
Lange, Rudolf: Theologie der Heimat : ein Beitrag zur Theologie der irdischen Wirklichkeiten. - Freilassing u.a.: Müller, 1965
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