38,311 research outputs found
Electronic Effects in Expansive Flow Under Hypersonic Conditions
Plasma effects in hypersonic shock tunnel nozzle using ai
The Reality and Measurement of the Wavefunction
Using a simple version of the model for the quantum measurement of a two
level system, the contention of Aharonov, Anandan, and Vaidman that one must in
certain circumstances give the wavefunction an ontological as well as an
epistemological significance is examined. I decide that their argument that the
wave function of a system can be measured on a single system fails to establish
the key point and that what they demonstrate is the ontological significance of
certain operators in the theory, with the wave function playing its usual
epistemological role.Comment: 10p
A Multiwavelength Investigation of Unidentified EGRET Sources
Statistical studies indicate that the 271 point sources of high-energy gamma
rays belong to two groups: a Galactic population and an isotropic extragalactic
population. Many unidentified extragalactic sources are certainly blazars, and
it is the intention of this work to uncover gamma-ray blazars missed by
previous attempts. Until recently, searches for blazar counterparts to
unidentified EGRET sources have focused on finding AGN that have 5-GHz radio
flux densities S_5 near or above 1 Jy. However, the recent blazar
identification of 3EG J2006-2321 (S_5 = 260 mJy) and other work suggest that
careful studies of weaker flat-spectrum sources may be fruitful. In this
spirit, error circles of 4 high-latitude unidentified EGRET sources have been
searched for 5-GHz sources. The gamma-ray sources are 3EG J1133+0033, 3EG
J1212+2304, 3EG J1222+2315, and 3EG J1227+4302. Within the error contours of
each of the four sources are found 6 radio candidates; by observing the
positions of the radio sources with the 0.81-m Tenagra II telescope it is
determined that 14 of these 24 radio sources have optical counterparts with R <
22. Eight of these from two different EGRET sources have been observed in the
B, V, and R bands in more than one epoch and the analysis of these data is
ongoing. Any sources that are found to be variable will be the objects of
multi-epoch polarimetry studies.Comment: 6 pages, 2 tables. To appear in Astrophysics & Space Scienc
Cycled operation of water vapor electrolysis cell Annual report, 1 Jan. - 31 Dec. 1969
Mathematical model of heat, mass, and momentum relationships in cyclic operation of water vapor electrolytic cell, and equilibrium conditions between gel matrix and vapo
Relational semantics of linear logic and higher-order model-checking
In this article, we develop a new and somewhat unexpected connection between
higher-order model-checking and linear logic. Our starting point is the
observation that once embedded in the relational semantics of linear logic, the
Church encoding of any higher-order recursion scheme (HORS) comes together with
a dual Church encoding of an alternating tree automata (ATA) of the same
signature. Moreover, the interaction between the relational interpretations of
the HORS and of the ATA identifies the set of accepting states of the tree
automaton against the infinite tree generated by the recursion scheme. We show
how to extend this result to alternating parity automata (APT) by introducing a
parametric version of the exponential modality of linear logic, capturing the
formal properties of colors (or priorities) in higher-order model-checking. We
show in particular how to reunderstand in this way the type-theoretic approach
to higher-order model-checking developed by Kobayashi and Ong. We briefly
explain in the end of the paper how his analysis driven by linear logic results
in a new and purely semantic proof of decidability of the formulas of the
monadic second-order logic for higher-order recursion schemes.Comment: 24 pages. Submitte
The prompt energy release of gamma-ray bursts using a cosmological k-correction
The fluences of gamma-ray bursts (GRBs) are measured with a variety of
instruments in different detector energy ranges. A detailed comparison of the
implied energy releases of the GRB sample requires, then, an accurate
accounting of this diversity in fluence measurements which properly corrects
for the redshifting of GRB spectra. Here, we develop a methodology to
``k-correct'' the implied prompt energy release of a GRB to a fixed co-moving
bandpass. This allows us to homogenize the prompt energy release of 17
cosmological GRBs (using published redshifts, fluences, and spectra) to two
common co-moving bandpasses: 20-2000 keV and 0.1 keV-10 MeV (``bolometric'').
While the overall distribution of GRB energy releases does not change
significantly by using a k-correction, we show that uncorrected energy
estimates systematically undercounts the bolometric energy by ~5% to 600%,
depending on the particular GRB. We find that the median bolometric
isotropic-equivalent prompt energy release is 2.2 x 10^{53} erg with an r.m.s.
scatter of 0.80 dex. The typical estimated uncertainty on a given k-corrected
energy measurement is ~20%.Comment: Accepted to the Astronomical Journal. 21 pages (LaTeX) and 4 figure
Labor Law—Agency Shop Agreements—Valid under NLRA—Subject to State Law—NLRB v. General Motors Corp.; Retail Clerks Intl Ass\u27n Local 1625 v. Schermerhorn
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