2,261 research outputs found
Evolutionary Relationships of Courtship Songs in the Parasitic Wasp Genus, Cotesia (Hymenoptera: Braconidae)
Acoustic signals play an important role in premating isolation based on sexual selection within many taxa. Many male parasitic wasps produce characteristic courtship songs used by females in mate selection. In Cotesia (Hymenoptera: Braconidae: Microgastrinae), courtship songs are generated by wing fanning with repetitive pulses in stereotypical patterns. Our objectives were to sample the diversity of courtship songs within Cotesia and to identify underlying patterns of differentiation. We compared songs among 12 of ca. 80 Cotesia species in North America, including ten species that have not been recorded previously. For Cotesia congregata, we compared songs of wasps originating from six different host-foodplant sources, two of which are considered incipient species. Songs of emergent males from wild caterpillar hosts in five different families were recorded, and pattern, frequency, and duration of song elements analyzed. Principal component analysis converted the seven elements characterized into four uncorrelated components used in a hierarchical cluster analysis and grouped species by similarity of song structure. Species songs varied significantly in duration of repeating pulse and buzz elements and/or in fundamental frequency. Cluster analysis resolved similar species groups in agreement with the most recent molecular phylogeny for Cotesia spp., indicating the potential for using courtship songs as a predictor of genetic relatedness. Courtship song analysis may aid in identifying closely related cryptic species that overlap spatially, and provide insight into the evolution of this highly diverse and agriculturally important taxon
A study of aircraft fire hazards related to natural electrical phenomena Final report, Jun. 1966 - Jul. 1967
Natural electrical phenomena as aircraft fire hazards, with study of flame propagation in fuel vent system
UNIFORM ACTS—CAN THE DEAD HAND CONTROL THE DEAD BODY? THE CASE FOR A UNIFORM BODILY REMAINS LAW
UNIFORM ACTS—CAN THE DEAD HAND CONTROL THE DEAD BODY? THE CASE FOR A UNIFORM BODILY REMAINS LAW
Scintillation light produced by low-energy beams of highly-charged ions
Measurements have been performed of scintillation light intensities emitted
from various inorganic scintillators irradiated with low-energy beams of
highly-charged ions from an electron beam ion source (EBIS) and an electron
cyclotron resonance ion source (ECRIS). Beams of xenon ions Xe with
various charge states between =2 and =18 have been used at energies
between 5 keV and 17.5 keV per charge generated by the ECRIS. The intensity of
the beam was typically varied between 1 and 100 nA. Beams of highly charged
residual gas ions have been produced by the EBIS at 4.5 keV per charge and with
low intensities down to 100 pA. The scintillator materials used are flat
screens of P46 YAG and P43 phosphor. In all cases, scintillation light emitted
from the screen surface was detected by a CCD camera. The scintillation light
intensity has been found to depend linearly on the kinetic ion energy per time
deposited into the scintillator, while up to =18 no significant contribution
from the ions' potential energy was found. We discuss the results on the
background of a possible use as beam diagnostics e.g. for the new HITRAP
facility at GSI, Germany.Comment: 6 pages, 8 figure
The Data Processing Pipeline for the Herschel-HIFI Instrument
The HIFI data processing pipeline was developed to systematically process
diagnostic, calibration and astronomical observations taken with the HIFI
science instrumentas part of the Herschel mission. The HIFI pipeline processed
data from all HIFI observing modes within the Herschel automated processing
environment, as well as, within an interactive environment. A common software
framework was developed to best support the use cases required by the
instrument teams and by the general astronomers. The HIFI pipeline was built on
top of that and was designed with a high degree of modularity. This modular
design provided the necessary flexibility and extensibility to deal with the
complexity of batch-processing eighteen different observing modes, to support
the astronomers in the interactive analysis and to cope with adjustments
necessary to improve the pipeline and the quality of the end-products. This
approach to the software development and data processing effort was arrived at
by coalescing the lessons learned from similar research based projects with the
understanding that a degree of foresight was required given the overall length
of the project. In this article, both the successes and challenges of the HIFI
software development process are presented. To support future similar projects
and retain experience gained lessons learned are extracted.Comment: 18 pages, 5 figure
The Turncoat Phenomenon: Role Conceptions of PR Practitioners Who Used To Be Journalists
For a long time, Dutch parliamentary journalists have shown an interest in migrating to the “other side” and becoming political PR professionals or spokespersons. The Dutch term used by journalists for colleagues who make this switch is “overloper” (turncoat). It is a term with a clear negative connotation, which says a lot about how journalists view the field of public relations. The relationship between journalism and public relati
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