2,603 research outputs found
Effect of Prey Density on Diurnal Activity and Ovarian Development in \u3ci\u3eCalosoma Calidum\u3c/i\u3e (Coleoptera: Carabidae): Implications for Biological Control of the Gypsy Moth, \u3ci\u3eLymantria Dispar (Lepidoptera: Lymantriidae)\u3c/i\u3e in the Midwest
Four feeding treatments were used in the laboratory to study the effects of the availability of prey on diurnal behavior and ovarian development of Calosoma calidum. Activity was closely monitored for six weeks. No significant differences were found between male and female behavior patterns. Diurnal beetle activity was found to be inversely related to prey density; in treatments where prey was available, diurnal activity declined during the course of the experiment. At the end of six weeks, dissections of female beetles showed that ovarian development and fat body quantity were dependent upon the number of prey available for consumption
Compton Scattered Transition Radiation from Very High Energy Particles
X-ray transition radiation can be used to measure the Lorentz factor of
relativistic particles. At energies approaching gamma = E/mc^2 = 10^5,
transition radiation detectors (TRDs) can be optimized by using thick (sim 5 -
10 mil) foils with large (5-10 mm) spacings. This implies X-ray energies >100
keV and the use of scintillators as the X-ray detectors. Compton scattering of
the X-rays out of the particle beam then becomes an important effect. We
discuss the design of very high energy detectors, the use of metal radiator
foils rather than the standard plastic foils, inorganic scintillators for
detecting Compton scattered transition radiation, and the application to the
ACCESS cosmic ray experiment.Comment: To be published, Astroparticle Physic
Probing the Interstellar Medium of External Galaxies Using Quasar Absorption Lines: the 3C 232/NGC 3067 System
Quasar absorption lines offer unique opportunities to probe the interstellar medium of external galaxies. Researchers present new optical and UV absorption line spectroscopy of the quasar 3C232 (z=0.55) revealing new detail in the foreground absorption system due to the bright, spiral galaxy NGC 3067 (cz=1420 km/s). Specifically, the spectra show evidence for two and possibly three separate absorption components in CaII and Na I spanning approx. 150 km/s. The original HI detection of Haschick and Burke (1975) corresponds to the strongest of these metal systems which exhibits doublet ratios consistent with saturation in both CaII and Na I. Due to the recent detection in HI emission of a tidal tail or finger of HI extending from the western edge of NGC 3067 through the position of 3C 232 (Carilli, van Gorkom and Stocke, 1989), the morphology of the HI absorber is now known and is not either a warped disk nor a spherical halo as had been proposed. New deep continuum and H alpha imaging provides a sensitive upper limit on the the ionizing continuum impinging upon this cloud (and thus a limit on the intensity of the extragalactic ionizing radiation field). Together with the observed UV spectrum of 3C 232, the optical emission line ratios and the deep H alpha imaging set a minimum distance between the quasar and the HI cloud disregarding redshift information. This limit strains the non-cosmological redshift interpretation for 3C 232 -- and this quasar is one of the original 5 3C quasars found to be too close to NGC galaxies as if by chance (Burbidge, Burbidge, Solomon and Strittmatter, 1972)
Simulation Studies of Delta-ray Backgrounds in a Compton-Scatter Transition Radiation Detector
In order to evaluate the response to cosmic-ray nuclei of a Compton-Scatter
Transition Radiation Detector in the proposed ACCESS space-based mission, a
hybrid Monte Carlo simulation using GEANT3 and an external transition radiation
(TR) generator routine was constructed. This simulation was employed to study
the effects of delta-ray production induced by high-energy nuclei and to
maximize the ratio of TR to delta-ray background. The results demonstrate the
ability of a Compton-Scatter Transition Radiation Detector to measure nuclei
from boron to iron up to Lorentz factors ~ 10^5 taking into account the steeply
falling power-law cosmic ray spectra.Comment: Presented at TRDs for the 3rd millennium: Third Workshop on advanced
Transition Radiation Detectors for accelerator and space applications,
Ostuni, Italy, September 2005, 4 pages, 2 figure
Three years of Fermi GBM Earth Occultation Monitoring: Observations of Hard X-ray/Soft Gamma-Ray Sources
The Gamma ray Burst Monitor (GBM) on board Fermi has been providing
continuous data to the astronomical community since 2008 August 12. In this
paper we present the results of the analysis of the first three years of these
continuous data using the Earth occultation technique to monitor a catalog of
209 sources. From this catalog, we detect 99 sources, including 40 low-mass
X-ray binary/neutron star systems, 31 high-mass X-ray binary neutron star
systems, 12 black hole binaries, 12 active galaxies, 2 other sources, plus the
Crab Nebula, and the Sun. Nine of these sources are detected in the 100-300 keV
band, including seven black-hole binaries, the active galaxy Cen A, and the
Crab. The Crab and Cyg X-1 are also detected in the 300-500 keV band. GBM
provides complementary data to other sky-monitors below 100 keV and is the only
all-sky monitor above 100 keV. Up-to-date light curves for all of the catalog
sources can be found at http://heastro.phys.lsu.edu/gbm/.Comment: 24 pages, 12 figures, accepted for publication in ApJ
TETRA Observation of Gamma Rays at Ground Level Associated with Nearby Thunderstorms
Terrestrial Gamma ray Flashes (TGFs) -- very short, intense bursts of
electrons, positrons, and energetic photons originating from terrestrial
thunderstorms -- have been detected with satellite instruments. TETRA, an array
of NaI(Tl) scintillators at Louisiana State University, has now been used to
detect similar bursts of 50 keV to over 2 MeV gamma rays at ground level. After
2.6 years of observation, twenty-four events with durations 0.02- 4.2 msec have
been detected associated with nearby lightning, three of them coincident events
observed by detectors separated by ~1000 m. Nine of the events occurred within
6 msec and 3 miles of negative polarity cloud-to-ground lightning strokes with
measured currents in excess of 20 kA. The events reported here constitute the
first catalog of TGFs observed at ground level in close proximity to the
acceleration site.Comment: To be published in Journal of Geophysical Research: Space Phys. 118,
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