Monitoring strip mining and reclamation with LANDSAT data in Belmont County, Ohio

The utility of LANDSAT digital data for mapping and monitoring surface mines in Belmont County, Ohio was investigated. Two data sets from 1976 and 1979 were processed to classify level 1 land covers and three strip mine categories in order to examine change over time and assess reclamation efforts. The two classifications were compared with aerial photographs. Results of the accuracy assessment show that both classifications are approximately 86 per cent correct, and that surface mine change detection (date-to-date comparison) is facilitated by the digital format of LANDSAT data

The rarity of terrestrial gamma-ray flashes

We report on the first search for Terrestrial Gamma-ray Flashes (TGFs) from altitudes where they are thought to be produced. The Airborne Detector for Energetic Lightning Emissions (ADELE), an array of gamma-ray detectors, was flown near the tops of Florida thunderstorms in August/September 2009. The plane passed within 10 km horizontal distance of 1213 lightning discharges and only once detected a TGF. If these discharges had produced TGFs of the same intensity as those seen from space, every one should have been seen by ADELE. Separate and significant nondetections are established for intracloud lightning, negative cloud-to-ground lightning, and narrow bipolar events. We conclude that TGFs are not a primary triggering mechanism for lightning. We estimate the TGF-to-flash ratio to be on the order of 10^(−2) to 10^(−3) and show that TGF intensities cannot follow the well-known power-law distribution seen in earthquakes and solar flares, due to our limits on the presence of faint events

Quality assessment in the blog space

Purpose: The purpose of this paper is the presentation of a new method for blog quality assessment. The method uses the temporal sequence of link creation events between blogs as an implicit source for the collective tacit knowledge of blog authors about blog quality. Design/methodology/approach: The blog data are processed by the novel method for the assessment of blog quality. The results are compared to Google Page Rank with respect to the Gold Standard, the BlogRazzi Bookmark Rank. Findings: The method is similar or better than Google Page Rank with respect to the chosen Gold Standard. Originality/value: The major contribution of this paper is the introduction of a novel method for blog quality assessment. Even though its superiority to other and more established methods cannot be proven in the context of this limited study, it enriches the toolset available for blog quality assessment and may become important for a deeper understanding of organizational learning. © Emerald Group Publishing Limited

Plastid DNA sequence diversity in wild grapevine samples (Vitis vinifera subsp. sylvestris) from the Caucasus region

DNA sequence diversity was investigated in three plastid regions (the trnH-psbA intergenic spacer, accDpsaI intergenic spacer and the rpl16 intron) in a group of 40 wild grape (Vitis vinifera subsp. sylvestris) samples from the South Caucasus. This group included 22 samples from Georgia, 9 samples from Azerbaijan, 2 samples from Armenia and 7 samples from Turkey. The South Caucasus region is widely believed to be the area in which grape domestication began, and the study of genetic diversity in this region is viewed as key to understanding grape domestication in general. Four plastid haplotypes are evident in the 40 samples, and are designated by their character states at each of the 4 polymorphic positions: AAAT – 22 samples, ATTT – 6 samples, GTAC – 1 sample, and ATAT – 11 samples. The AAAT haplotype is restricted to Georgia and Azerbaijan, the ATAT haplotype is distributed across the entire study area, the ATTT haplotype is distributed in the southern part of the study area from the Black Sea to the Caspian Sea. The single GTAC haplotype was only found in southwestern Georgia. The AAAT haplotype is restricted to both wild (V. vinifera subsp. sylvestris) and cultivated (V. vinifera subsp. vinifera) grape samples from the Caucasus. This observation and the presence of all other plastid haplotypes observed in a previous study of worldwide grape cultivars highlight both unique and high levels of genetic variation in wild grape (V. vinifera subsp. sylvestris) from the greater Caucasus region.

The Cosmic Background Imager

Design and performance details are given for the Cosmic Background Imager (CBI), an interferometer array that is measuring the power spectrum of fluctuations in the cosmic microwave background radiation (CMBR) for multipoles in the range 400 < l < 3500. The CBI is located at an altitude of 5000 m in the Atacama Desert in northern Chile. It is a planar synthesis array with 13 0.9-m diameter antennas on a 6-m diameter tracking platform. Each antenna has a cooled, low-noise receiver operating in the 26-36 GHz band. Signals are cross-correlated in an analog filterbank correlator with ten 1 GHz bands. This allows spectral index measurements which can be used to distinguish CMBR signals from diffuse galactic foregrounds. A 1.2 kHz 180-deg phase switching scheme is used to reject cross-talk and low-frequency pick-up in the signal processing system. The CBI has a 3-axis mount which allows the tracking platform to be rotated about the optical axis, providing improved (u,v) coverage and a powerful discriminant against false signals generated in the receiving electronics. Rotating the tracking platform also permits polarization measurements when some of the antennas are configured for the orthogonal polarization.Comment: 14 pages. Accepted for publication in PASP. See also http://www.astro.caltech.edu/~tjp/CBI

Low-Resolution Imaging Spectrometer for the Keck Telescope

The Low Resolution Imaging Spectrometer is designed for use at the Cassegrain focus of the Keck 10-m telescope. It provides the capability of acquiring low resolution (R equals 1000 to 5000) digital spectra, as well as 6 X 8 arc-minute moderately high spatial resolution (4.65 pixels/arc-second) direct images. Spectroscopy can be carried out with single slits which are 3 arc-minutes long. In addition punched multi-slits can also be employed which allow for the acquisition of at least forty spectra simultaneously. Since the instrument is designed to be as efficient as possible, it is a double spectrograph, with a dichroic splitting the blue and red light into separate optical paths after the collimator. Only the red side has been constructed thus far. With a 2048 by 2048 thinned Tektronix CCD as the detector the total efficiency of the red side at the peak of the grating blaze is predicted to be nearly 40%. Results of the commissioning observing runs will be described

The Keck Low-Resolution Imaging Spectrometer

The Low Resolution Imaging Spectrometer (LRIS) for the Cassegrain focus of the Keck 10-m telescope on Mauna Kea is described. It has an imaging mode so it can also be used for taking direct images. The field of view in both spectrographic and imaging modes is 6 by 7.8 arcmin. It can be used with both conventional slits and custom-punched slit masks. The optical quality of the spectrograph is good enough to take full advantage of the excellent imaging properties of the telescope itself. The detector is a cooled back-illuminated Tektronics Inc. 2048 X 2048 CCD which gives a sampling rate of 4.685 pixels per arcsec. In the spectrographic mode the spectrograph has a maximum efficiency at the peak of the grating blaze of 32%-34% for the two lowest resolution gratings and 28% for the 1200 g mm^(-1) grating. This efficiency includes the detector but not the telescope or the atmosphere

Mass equidistribution of Hilbert modular eigenforms

Let F be a totally real number field, and let f traverse a sequence of non-dihedral holomorphic eigencuspforms on GL(2)/F of weight (k_1,...,k_n), trivial central character and full level. We show that the mass of f equidistributes on the Hilbert modular variety as max(k_1,...,k_n) tends to infinity. Our result answers affirmatively a natural analogue of a conjecture of Rudnick and Sarnak (1994). Our proof generalizes the argument of Holowinsky-Soundararajan (2008) who established the case F = Q. The essential difficulty in doing so is to adapt Holowinsky's bounds for the Weyl periods of the equidistribution problem in terms of manageable shifted convolution sums of Fourier coefficients to the case of a number field with nontrivial unit group.Comment: 40 pages; typos corrected, nearly accepted for

Deep Broadband Observations of the Distant Gamma-ray Blazar PKS 1424+240

We present deep VERITAS observations of the blazar PKS 1424+240, along with contemporaneous Fermi Large Area Telescope, Swift X-ray Telescope and Swift UV Optical Telescope data between 2009 February 19 and 2013 June 8. This blazar resides at a redshift of $z\ge0.6035$, displaying a significantly attenuated gamma-ray flux above 100 GeV due to photon absorption via pair-production with the extragalactic background light. We present more than 100 hours of VERITAS observations from three years, a multiwavelength light curve and the contemporaneous spectral energy distributions. The source shows a higher flux of (2.1$\pm0.3$)$\times10^{-7}$ ph m$^{-2}$s$^{-1}$ above 120 GeV in 2009 and 2011 as compared to the flux measured in 2013, corresponding to (1.02$\pm0.08$)$\times10^{-7}$ ph m$^{-2}$s$^{-1}$ above 120 GeV. The measured differential very high energy (VHE; $E\ge100$ GeV) spectral indices are $\Gamma=$3.8$\pm$0.3, 4.3$\pm$0.6 and 4.5$\pm$0.2 in 2009, 2011 and 2013, respectively. No significant spectral change across the observation epochs is detected. We find no evidence for variability at gamma-ray opacities of greater than $\tau=2$, where it is postulated that any variability would be small and occur on longer than year timescales if hadronic cosmic-ray interactions with extragalactic photon fields provide a secondary VHE photon flux. The data cannot rule out such variability due to low statistics.Comment: ApJL accepted March 17, 201