1,244 research outputs found
A Comparison of Continuously Controlled and Controlled K-theory
We define an unreduced version of the e-controlled lower -theoretic groups
of Ranicki and Yamasaki, and Quinn. We show that the reduced versions of our
groups coincide (in the inverse limit and its first derived, ) with
those of Ranicki and Yamasaki. We also relate the controlled groups to the
continuously controlled groups of Anderson and Munkholm, and to the Quinn
homology groups of Quinn
YF-12 cooperative airframe/propulsion control system program, volume 1
Several YF-12C airplane analog control systems were converted to a digital system. Included were the air data computer, autopilot, inlet control system, and autothrottle systems. This conversion was performed to allow assessment of digital technology applications to supersonic cruise aircraft. The digital system was composed of a digital computer and specialized interface unit. A large scale mathematical simulation of the airplane was used for integration testing and software checkout
Who Publishes in “Predatory” Journals?
Many open access journals have a reputation for being of low quality and being dishonest with regard to peer review and publishing costs. Such journals are labeled “predatory” journals. This study examines author profiles for some of these “predatory” journals as well as for groups of more well-recognized open access journals. We collect and analyze the publication record, citation count, and geographic location of authors from the various groups of journals. Statistical analyses verify that each group of journals has a distinct author population. Those who publish in “predatory” journals are, for the most part, young and inexperienced researchers from developing countries. We believe that economic and sociocultural conditions in these developing countries have contributed to the differences found in authorship between “predatory” and “nonpredatory” journals
Reading and writing charge on graphene devices
We use a combination of charge writing and scanning gate microscopy to map
and modify the local charge neutrality point of graphene field-effect devices.
We give a demonstration of the technique by writing remote charge in a thin
dielectric layer over the graphene-metal interface and detecting the resulting
shift in local charge neutrality point. We perform electrostatic simulations to
characterize the gating effect of a realistic scanning probe tip on a graphene
bilayer and find a good agreement with the experimental results
Five High-Redshift Quasars Discovered in Commissioning Imaging Data of the Sloan Digital Sky Survey
We report the discovery of five quasars with redshifts of 4.67 - 5.27 and
z'-band magnitudes of 19.5-20.7 M_B ~ -27. All were originally selected as
distant quasar candidates in optical/near-infrared photometry from the Sloan
Digital Sky Survey (SDSS), and most were confirmed as probable high-redshift
quasars by supplementing the SDSS data with J and K measurements. The quasars
possess strong, broad Lyman-alpha emission lines, with the characteristic sharp
cutoff on the blue side produced by Lyman-alpha forest absorption. Three
quasars contain strong, broad absorption features, and one of them exhibits
very strong N V emission. The amount of absorption produced by the Lyman-alpha
forest increases toward higher redshift, and that in the z=5.27 object (D_A ~
0.7) is consistent with a smooth extrapolation of the absorption seen in lower
redshift quasars. The high luminosity of these objects relative to most other
known objects at z >~ 5 makes them potentially valuable as probes of early
quasar properties and of the intervening intergalactic medium.Comment: 13 pages in LaTex format, two postscirpt figures. Submitted to the
Astronomical Journa
Young migrants’ narratives of collective identifications and belonging
The article sheds light on the intricate relationship between migration, ‘identity’ and belonging by focusing on young migrants in the context of Greek society. Based upon a qualitative study of youth identities, the key objective is to examine their collective identifications, formed through the dialectic of self-identification and categorization. The analysis of young migrants’ narratives unpacks how their sense of belonging and emotional attachments to their countries of origin and
settlement are mediated by processes of racialization and ‘othering’
The Luminosity Function of Galaxies in SDSS Commissioning Data
During commissioning observations, the Sloan Digital Sky Survey (SDSS) has
produced one of the largest existing galaxy redshift samples selected from CCD
images. Using 11,275 galaxies complete to r^* = 17.6 over 140 square degrees,
we compute the luminosity function of galaxies in the r^* band over a range -23
< M < -16 (for h=1). The result is well-described by a Schechter function with
parameters phi_* = 0.0146 +/- 0.0012 h^3 Mpc^{-3}, M_* = -20.83 +/- 0.03, and
alpha = -1.20 +/- 0.03. The implied luminosity density in r^* is j = (2.6 +/-
0.3) x 10^8 h L_sun Mpc^{-3}. The surface brightness selection threshold has a
negligible impact for M < -18. We measure the luminosity function in the u^*,
g^*, i^*, and z^* bands as well; the slope at low luminosities ranges from
alpha=-1.35 to alpha=-1.2. We measure the bivariate distribution of r^*
luminosity with half-light surface brightness, intrinsic color, and morphology.
High surface brightness, red, highly concentrated galaxies are on average more
luminous than low surface brightness, blue, less concentrated galaxies. If we
synthesize results for R-band or b_j-band using the Petrosian magnitudes with
which the SDSS measures galaxy fluxes, we obtain luminosity densities 2.0 times
that found by the Las Campanas Redshift Survey in R and 1.4 times that found by
the Two-degree Field Galaxy Redshift Survey in b_j. We are able to reproduce
the luminosity functions obtained by these surveys if we also mimic their
isophotal limits for defining galaxy magnitudes, which are shallower and more
redshift dependent than the Petrosian magnitudes used by the SDSS. (Abridged)Comment: 49 pages, including 23 figures, accepted by AJ; some minor textual
changes, plus an important change in comparison to LCR
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