We present a detailed statistical analysis of the correlation between radio and gamma-ray emission of the active galactic nuclei (AGNs) detected by Fermi during its first year of operation, with the ...largest data sets ever used for this purpose. We use both archival interferometric 8.4 GHz data (from the Very Large Array and ATCA, for the full sample of 599 sources) and concurrent single-dish 15 GHz measurements from the Owens Valley Radio Observatory (OVRO, for a sub sample of 199 objects). Our unprecedentedly large sample permits us to assess with high accuracy the statistical significance of the correlation, using a surrogate data method designed to simultaneously account for common-distance bias and the effect of a limited dynamical range in the observed quantities. We find that the statistical significance of a positive correlation between the centimeter radio and the broadband (E > 100 MeV) gamma-ray energy flux is very high for the whole AGN sample, with a probability of <10--7 for the correlation appearing by chance. Using the OVRO data, we find that concurrent data improve the significance of the correlation from 1.6 X 10--6 to 9.0 X 10--8. Our large sample size allows us to study the dependence of correlation strength and significance on specific source types and gamma-ray energy band. We find that the correlation is very significant (chance probability < 10--7) for both flat spectrum radio quasars and BL Lac objects separately; a dependence of the correlation strength on the considered gamma-ray energy band is also present, but additional data will be necessary to constrain its significance.
The tribe Aedini (Family Culicidae) contains approximately one-quarter of the known species of mosquitoes, including vectors of deadly or debilitating disease agents. This tribe contains the genus ...Aedes, which is one of the three most familiar genera of mosquitoes. During the past decade, Aedini has been the focus of a series of extensive morphology-based phylogenetic studies published by Reinert, Harbach, and Kitching (RH&K). Those authors created 74 new, elevated or resurrected genera from what had been the single genus Aedes, almost tripling the number of genera in the entire family Culicidae. The proposed classification is based on subjective assessments of the "number and nature of the characters that support the branches" subtending particular monophyletic groups in the results of cladistic analyses of a large set of morphological characters of representative species. To gauge the stability of RH&K's generic groupings we reanalyzed their data with unweighted parsimony jackknife and maximum-parsimony analyses, with and without ordering 14 of the characters as in RH&K. We found that their phylogeny was largely weakly supported and their taxonomic rankings failed priority and other useful taxon-naming criteria. Consequently, we propose simplified aedine generic designations that 1) restore a classification system that is useful for the operational community; 2) enhance the ability of taxonomists to accurately place new species into genera; 3) maintain the progress toward a natural classification based on monophyletic groups of species; and 4) correct the current classification system that is subject to instability as new species are described and existing species more thoroughly defined. We do not challenge the phylogenetic hypotheses generated by the above-mentioned series of morphological studies. However, we reduce the ranks of the genera and subgenera of RH&K to subgenera or informal species groups, respectively, to preserve stability as new data become available.
The Oriented Scintillation Spectrometer Experiment on the Arthur Holly Compton Gamma Ray Observatory satellite uses four actively shielded NaI (Tl)-CsI(Na) phoswich detectors to provide gamma-ray ...line and continuum detection capability in the 0.05-10 MeV energy range. The instrument includes secondary capabilities for gamma-ray and neutron detection between 10 and 250 MeV. The detectors have 3.8 deg x 11.04 deg (FWHM) fields of view defined by tungsten collimators. Each detector has an independent, single-axis orientation system which permits offset pointing from the spacecraft Z-axis for background measurements and multitarget observations. The instrument, and its calibration and performance, are described.
GLAST is the next generation space-based gamma ray telescope for the energy range 30 MeV-300 GeV, to be launched by NASA in 2007. For photon energy measurements it will use a CsI crystal calorimeter ...made of 16 identical modules. The engineering module (EM) calorimeter is the first full scale prototype built with the same technology as flight modules to verify the design and technological choices before starting calorimeter production. The module contains 96 CsI crystals, supported by a carbon fiber composite structure and read out with silicon PIN photodiodes from both ends. In this paper, we report the results of EM calibration using cosmic ray muons and charge injection during environmental tests. The EM showed stable functioning in the required temperature range from -30 C to +50 C during six months of continuous testing, including seven thermal vacuum cycles between -30 C and +50 C and vibration testing with amplitudes significantly higher than expected during launch. None of 96 crystals experienced mechanical or optical degradation after the tests. The longitudinal position measurement is accomplished using light asymmetry from two ends of each crystal, providing /spl sim/6--12 mm position resolution (2-4% of crystal length) for cosmic ray muons. The production of flight modules will start in late 2003.
Neurotoxic methylmercury (MeHg) accumulates in rice grain from paddy soil, where its concentration is controlled by microbial mercury methylation and demethylation. Both up- and down-regulation of ...methylation is known to occur in the presence of rice plants in comparison to non-vegetated paddy soils; the influence of rice plant presence/absence on demethylation is unknown. To assess the concurrent influence of rice plant presence/absence on methylation and demethylation, and to determine which process was more dominant in controlling soil MeHg concentrations, we maintained six rhizoboxes of paddy soil with and without rice plants. At the peak of plant growth, we simultaneously measured ambient MeHg, ambient inorganic mercury (IHg), and potential rate constants of methylation and demethylation (Kmeth and Kdemeth) in soil using stable isotope tracers and ID-GC-ICPMS. We also measured organic matter content, elemental S, and water-extractable sulfate. We found MeHg concentrations were differentially controlled by MeHg production and degradation processes, depending on whether plants were present. In non-vegetated boxes, MeHg concentration was controlled by Kmeth, as evidenced by a strong and positive correlation, while Kdemeth had no relation to MeHg concentration. These results indicate methylation was the dominant driver of MeHg concentration in non-vegetated soil. In vegetated boxes, Kdemeth strongly and negatively predicted MeHg concentration, indicating that demethylation was the dominant control in soil with plants. MeHg concentration, Kmeth, and % MeHg all had significantly less variance in vegetated than in non-vegetated soils due to a consistent elimination of greater values. This pattern suggests that reduced MeHg production capacity was a secondary control on MeHg concentrations in vegetated soils. We observed no difference in the magnitude or variance of Kdemeth between treatments, suggesting that demethylation was robust to soil chemical conditions influenced by the plant, perhaps because of a wider taxonomic diversity of demethylators. Our results suggest that methylation and demethylation processes could both be leveraged to alter MeHg concentrations in rice paddy soil.
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•MeHg concentrations are controlled by methylation in soil without plants.•Both methylation and demethylation drive MeHg concentrations in vegetated soil.•IHg bioavailability and C and S dynamics may explain methylation patterns.•Drivers of demethylation should be identified to harness this process as a management strategy.
Personal protection measures against biting arthropods include topical insect repellents, area repellents, insecticide‐treated bednets and treated clothing. The literature on the effectiveness of ...personal protection products against arthropods is mainly limited to studies of prevention of bites, rather than prevention of disease. Tungiasis was successfully controlled by application of topical repellents and scrub typhus was reduced through the use of treated clothing. Successful reduction of leishmaniasis was achieved through the use of topical repellents, treated bednets and treated clothing in individual studies. Malaria has been reduced by the use of insecticide‐treated bednets (ITN), certain campaigns involving topical repellents, and the combination of treated bednets and topical repellents. Although area repellents such as mosquito coils are used extensively, their ability to protect humans from vector‐transmitted pathogens has not been proven. Taken together, the literature indicates that personal protection measures must be used correctly to be effective. A study that showed successful control of malaria by combining treated bednets and topical repellents suggests that combinations of personal protection measures are likely to be more effective than single methods. Implementation of successful programmes based on personal protection will require a level of cooperation commonly associated with other basic societal functions, such as education and food safety.
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