14,865 research outputs found
The effect of electron beam pitch angle and density gradient on solar type III radio bursts
Copyright 2012 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. This article appeared in Physics of Plasmas 19, 112903 (2012) and may be found at .supplemental material at http://astro.qmul.ac.uk/~tsiklauri/sp.htmlsupplemental material at http://astro.qmul.ac.uk/~tsiklauri/sp.htm
Smelly maps: the digital life of urban smellscapes
Smell has a huge influence over how we perceive places. Despite its importance, smell has been crucially overlooked by urban planners and scientists alike, not least because it is difficult to record and analyze at scale. One of the authors of this paper has ventured out in the urban world and conducted ``smellwalks'' in a variety of cities: participants were exposed to a range of different smellscapes and asked to record their experiences. As a result, smell-related words have been collected and classified, creating the first dictionary for urban smell. Here we explore the possibility of using social media data to reliably map the smells of entire cities. To this end, for both Barcelona and London, we collect geo-referenced picture tags from Flickr and Instagram, and geo-referenced tweets from Twitter. We match those tags and tweets with the words in the smell dictionary. We find that smell-related words are best classified in ten categories. We also find that specific categories (e.g., industry, transport, cleaning) correlate with governmental air quality indicators, adding validity to our study
The GSC-II-based survey of ancient cool white dwarfs I. The sample of spectroscopically confirmed WDs
The GSC-II white dwarf survey was designed to identify faint and high proper
motion objects, which we used to define a new and independent sample of cool
white dwarfs. With this survey we aim to derive new constraints on the halo
white dwarf space density. Also, these data can provide information on the age
of thick disk and halo through the analysis of the luminosity function. On the
basis of astrometric and photometric parameters, we selected candidates with mu
> 0.28 as/yr and R_F > 16 in an area of 1150 square degrees. Then, we separated
white dwarfs from late type dwarfs and subdwarfs by means of the reduced proper
motion diagram. Finally, spectroscopic follow-up observations were carried out
to confirm the white dwarf nature of the selected candidates. We found 41 white
dwarfs of which 24 are new discoveries. Here we present the full sample and for
each object provide positions, absolute proper motions, photometry, and
spectroscopy.Comment: 14 pages, 7 figures, submitted to A&
Large-scale and significant expression from pseudogenes in Sodalis glossinidius â a facultative bacterial endosymbiont
The majority of bacterial genomes have high coding efficiencies, but there are some genomes of intracellular bacteria that have low gene density. The genome of the endosymbiont Sodalis glossinidius contains almost 50â% pseudogenes containing mutations that putatively silence them at the genomic level. We have applied multiple âomicâ strategies, combining Illumina and Pacific Biosciences Single-Molecule Real-Time DNA sequencing and annotation, stranded RNA sequencing and proteome analysis to better understand the transcriptional and translational landscape of Sodalis pseudogenes, and potential mechanisms for their control. Between 53 and 74â% of the Sodalis transcriptome remains active in cell-free culture. The mean sense transcription from coding domain sequences (CDSs) is four times greater than that from pseudogenes. Comparative genomic analysis of six Illumina-sequenced Sodalis isolates from different host Glossina species shows pseudogenes make up ~40â% of the 2729 genes in the core genome, suggesting that they are stable and/or that Sodalis is a recent introduction across the genus Glossina as a facultative symbiont. These data shed further light on the importance of transcriptional and translational control in deciphering hostâmicrobe interactions. The combination of genomics, transcriptomics and proteomics gives a multidimensional perspective for studying prokaryotic genomes with a view to elucidating evolutionary adaptation to novel environmental niches
Relationships between lamb carcass quality traits measured by X-ray computed tomography (CT) and current UK-hill sheep breeding goals.
The NIRSPEC Brown Dwarf Spectroscopic Survey II: High-Resolution J-Band Spectra of M, L and T Dwarfs
We present a sequence of high resolution (R~20,000 or 15 km/s) infrared
spectra of stars and brown dwarfs spanning spectral types M2.5 to T6.
Observations of 16 objects were obtained using eight echelle orders to cover
part of the J-band from 1.165-1.323 micron with NIRSPEC on the Keck II
telescope. By comparing opacity plots and line lists, over 200 weak features in
the J-band are identified with either FeH or H2O transitions. Absorption by FeH
attains maximum strength in the mid-L dwarfs, while H2O absorption becomes
systematically stronger towards later spectral types. Narrow resolved features
broaden markedly after the M to L transition. Our high resolution spectra also
reveal that the disappearance of neutral Al lines at the boundary between M and
L dwarfs is remarkably abrupt, presumably because of the formation of grains.
Neutral Fe lines can be traced to mid-L dwarfs before Fe is removed by
condensation. The neutral potassium (K I) doublets that dominate the J-band
have pressure broadened wings that continue to broaden from ~50 km/s (FWHM) at
mid-M to ~500 km/s at mid-T. In contrast however, the measured
pseudo-equivalent widths of these same lines reach a maximum in the mid-L
dwarfs. The young L2 dwarf, G196-3B, exhibits narrow potassium lines without
extensive pressure-broadened wings, indicative of a lower gravity atmosphere.
Kelu-1AB, another L2, has exceptionally broad infrared lines, including FeH and
H2O features, confirming its status as a rapid rotator. In contrast to other
late T objects, the peculiar T6 dwarf 2MASS 0937+29 displays a complete absence
of potassium even at high resolution, which may be a metallicity effect or a
result of a cooler, higher-gravity atmosphere.Comment: 53 pages, 21 figures, data will be available at
http://www.astro.ucla.edu/~mclean/BDSSarchive
Analysis and design of on-grade reinforced concrete track support structures
For the improvement of rail service, the Department of Transportation, Federal Rail Administration, is sponsoring a test track on the Atchison, Topeka, and Santa Fe Railway. The test track will contain nine separate rail support structures, including one conventional section for control and three reinforced concrete structures on grade, one slab and two beam sections. The analysis and design of these latter structures was accomplished by means of the finite element method, NASTRAN, and is presented
- âŚ