5,497 research outputs found
Manganese-56 coincidence-counting facility precisely measures neutron-source strength
Precise measurement of neutron-source strength is provided by a manganese 56 coincidence-counting facility using the manganese-bath technique. This facility combines nuclear instrumentation with coincidence-counting techniques to handle a wide variety of radioisotope-counting requirements
Public awareness and knowledge of herpes labialis
Between 20% and 40% of the population is estimated to suffer from episodes of recurrent herpes labialis, although few reports in the literature have addressed the public awareness of this infection in the general population. The aims of this study were to determine the existing level of awareness and knowledge of this disease and to assess the source of this knowledge, the ability of the public to recognize the characteristics of the disease and the behavior of patients with clinical cases of disease manifestation. To this end, 2,000 individuals (961 male and 1,039 female) of 14 years of age and older were surveyed using the ECOcapi system [Eurisko Consumer Omnibus-CAPI (computer-assisted personal interviewing) version]. Eighty-nine percent of those surveyed had some knowledge of herpes labialis; 92% were able to refer to at least one symptom of herpes labialis, 91% were able to identify correctly his infection from pictures, and 45% had experienced personally at least one episode of herpes labialis infection. The majority of the individuals suffering from herpes labialis self-medicated using a topical therapy. Women were found to be affected more commonly by herpes labialis than men [OR 1.42 (1.18-1.70)], and women were also more likely to recognize the disease [OR 1.65 (1.30-2.08)] and to seek medical advice for the condition [OR 1.38 (1.12-1.70)]. In conclusion, herpes labialis is a common and well-known condition, and it is often self-diagnosed correctly, as the prodromal phase and the use of self-medication are very common. J. Med. Virol. © 2011 Wiley Periodicals, Inc
Breakups hurt: Party switching and perceived proximity between politicians and their party
What are the effects of party defections on the attitudes of politicians who remain loyal to the party? We answer by combining multiple sources of data into a comprehensive novel data set on parliamentary party switching, to estimate how this affects the perceived distance between a politician and his party. Focusing on the theory of cognitive dissonance and the black sheep effect, we hypothesize that politicians perceive themselves closer to their parties when those parties recently suffered defections. The effect should be greater among incumbent politicians as they directly experience divisions, but also among officials dissatisfied with the leadership as their dissonance should be stronger. Statistical analyses of data from two elite surveys, on a sample of 13,256 politicians belonging to 92 parties that ran in 28 elections held between 2005 and 2015 in 14 countries, provide support for our hypotheses and shed light on the consequences of intra-party defections
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Full-field and anomaly initialization using a low-order climate model: a comparison and proposals for advanced formulations
Initialization techniques for seasonal-to-decadal climate predictions fall into two main categories; namely full-field initialization (FFI) and anomaly initialization (AI). In the FFI case the initial model state is replaced by the best possible available estimate of the real state. By doing so the initial error is efficiently reduced but, due to the unavoidable presence of model deficiencies, once the model is let free to run a prediction, its trajectory drifts away from the observations no matter how small the initial error is. This problem is partly overcome with AI where the aim is to forecast future anomalies by assimilating observed anomalies on an estimate of the model climate.
The large variety of experimental setups, models and observational networks adopted worldwide make it difficult to draw firm conclusions on the respective advantages and drawbacks of FFI and AI, or to identify distinctive lines for improvement. The lack of a unified mathematical framework adds an additional difficulty toward the design of adequate initialization strategies that fit the desired forecast horizon, observational network and model at hand.
Here we compare FFI and AI using a low-order climate model of nine ordinary differential equations and use the notation and concepts of data assimilation theory to highlight their error scaling properties. This analysis suggests better performances using FFI when a good observational network is available and reveals the direct relation of its skill with the observational accuracy. The skill of AI appears, however, mostly related to the model quality and clear increases of skill can only be expected in coincidence with model upgrades.
We have compared FFI and AI in experiments in which either the full system or the atmosphere and ocean were independently initialized. In the former case FFI shows better and longer-lasting improvements, with skillful predictions until month 30. In the initialization of single compartments, the best performance is obtained when the stabler component of the model (the ocean) is initialized, but with FFI it is possible to have some predictive skill even when the most unstable compartment (the extratropical atmosphere) is observed.
Two advanced formulations, least-square initialization (LSI) and exploring parameter uncertainty (EPU), are introduced. Using LSI the initialization makes use of model statistics to propagate information from observation locations to the entire model domain. Numerical results show that LSI improves the performance of FFI in all the situations when only a portion of the system's state is observed. EPU is an online drift correction method in which the drift caused by the parametric error is estimated using a short-time evolution law and is then removed during the forecast run. Its implementation in conjunction with FFI allows us to improve the prediction skill within the first forecast year.
Finally, the application of these results in the context of realistic climate models is discussed
Simulated synchrotron and Inverse Compton emission from Pulsar Wind Nebulae
We present a complete set of diagnostic tools aimed at reproducing synthetic
non-thermal (synchrotron and/or Inverse Compton, IC) emissivity, integrated
flux energy, polarization and spectral index simulated maps in comparison to
observations. The time dependent relativistic magnetohydrodynamic (RMHD)
equations are solved with a shock capturing code together with the evolution of
the maximum particles energy. Applications to Pulsar Wind Nebulae (PWNe) are
shown.Comment: 3 pages, 7 figures, proceeding of the conference "40 Years of Pulsars
", 12-17 August 2007, Montreal, Canada, submitted to AI
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The pgip family in soybean and three other legume species: evidence for a birth-and-death model of evolution
Polygalacturonase-inhibiting proteins (PGIPs) are leucine-rich repeat (LRR) plant cell wall glycoproteins involved in plant immunity. They are typically encoded by gene families with a small number of gene copies whose evolutionary origin has been poorly investigated. Here we report the complete characterization of the full complement of the pgip family in soybean (Glycine max [L.] Merr.) and the characterization of the genomic region surrounding the pgip family in four legume species. Results: BAC clone and genome sequence analyses showed that the soybean genome contains two pgip loci. Each locus is composed of three clustered genes that are induced following infection with the fungal pathogen Sclerotinia sclerotiorum (Lib.) de Bary, and remnant sequences of pgip genes. The analyzed homeologous soybean genomic regions (about 126 Kb) that include the pgip loci are strongly conserved and this conservation extends also to the genomes of the legume species Phaseolus vulgaris L., Medicago truncatula Gaertn. and Cicer arietinum L., each containing a single pgip locus. Maximum likelihood-based gene trees suggest that the genes within the pgip clusters have independently undergone tandem duplication in each species. Conclusions: The paleopolyploid soybean genome contains two pgip loci comprised in large and highly conserved duplicated regions, which are also conserved in bean, M. truncatula and C. arietinum. The genomic features of these legume pgip families suggest that the forces driving the evolution of pgip genes follow the birth-and-death model, similar to that proposed for the evolution of resistance (R) genes of NBS-LRR-type
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