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On the uniform domination number of a finite simple group
Let be a finite simple group. By a theorem of Guralnick and Kantor,
contains a conjugacy class such that for each non-identity element , there exists with . Building on this deep
result, we introduce a new invariant , which we call the uniform
domination number of . This is the minimal size of a subset of conjugate
elements such that for each , there exists with . (This invariant is closely related to the total
domination number of the generating graph of , which explains our choice of
terminology.) By the result of Guralnick and Kantor, we have for some conjugacy class of , and the aim of this paper
is to determine close to best possible bounds on for each family
of simple groups. For example, we will prove that there are infinitely many
non-abelian simple groups with . To do this, we develop a
probabilistic approach, based on fixed point ratio estimates. We also establish
a connection to the theory of bases for permutation groups, which allows us to
apply recent results on base sizes for primitive actions of simple groups.Comment: 35 pages; to appear in Trans. Amer. Math. So
A semibuoyant vehicle for general transportation missions
The concept of a small, semibuoyant, lifting-body airship with either a disposable or nondisposable buoyant fluid is discussed. Estimations of fuel consumption, payload capability, power requirements and productivity are made and compared to other flight systems. Comparisons are made on the basis of equal cost vehicles. The assumption is made that, to a first-order approximation, the costs of developing, procuring, and operating a commercial air transport vehicle are proportional to vehicle empty weight. It must be noted that no historical cost data exist for the lifting-body airship and therefore these comparisons must be considered preliminary
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Joseph Smith’s First Vision: New Methods for the Analysis of Experience-Related Texts
Design, cost, and advanced technology applications for a military trainer aircraft
The potential impact is examined of advanced aerodynamic and propulsive technologies in terms of operating and acquisition costs on conceptual mission and performance requirements for a future undergraduate jet pilot trainer aircraft
The response of self-graviting protostellar discs to slow reduction in cooling timescale: the fragmentation boundary revisited
A number of previous studies of the fragmentation of self-gravitating
protostellar discs have modeled radiative cooling with a cooling timescale
(t_{cool}) parameterised as a simple multiple (beta_{cool}) of the local
dynamical timescale. Such studies have delineated the `fragmentation boundary'
in terms of a critical value of beta_{cool} (beta_{crit}), where the disc
fragments if beta_{cool} < beta_{crit}. Such an approach however begs the
question of how in reality a disc could ever be assembled with beta_{cool} <
beta_{crit}. Here we adopt the more realistic approach of gradually reducing
beta_{cool}, as might correspond to changes in thermal regime due to secular
changes in the disc density profile. We find that when beta_{cool} is gradually
reduced (on a timescale longer than t_{cool}), the disc is stabilised against
fragmentation, compared with models in which beta_{cool} is reduced rapidly. We
therefore conclude that a disc's ability to remain in a self-regulated,
self-gravitating state (without fragmentation) is partly dependent on its
thermal history, as well as its current cooling rate. Nevertheless, a slow
reduction in t_{cool} appears only to lower the fragmentation boundary by about
a factor two in t_{cool} and thus only permits maximum alpha values
(parameterising the efficiency of angular momentum transfer in the disc) that
are about a factor two higher than determined hitherto. Our results therefore
do not undermine the notion of a fundamental upper limit to the heating rate
that can be delivered by gravitational instabilities before the disc is subject
to fragmentation. An important implication of this work, therefore, is that
self-gravitating discs can enter into the regime of fragmentation via secular
evolution and it is not necessary to invoke rapid (impulsive) events to trigger
fragmentation.Comment: accepted for publication in MNRA
PRICE TRANSMISSION, THRESHOLD BEHAVIOR, AND ASYMMETRIC ADJUSTMENT IN THE U.S. PORK SECTOR
The US pork sector has experienced many significant structural changes in recent years. Such changes may have influenced price dynamics and transmission of shocks through marketing channels. We investigate linkages among farm, wholesale, and retail markets using weekly price data for the period covering 1987 through 1998. Our analysis uses a threshold cointegration model that permits asymmetric adjustment to positive and negative price shocks. Our results reveal important asymmetries. Our results are consistent with existing literature which has determined that price adjustment patterns are unidirectional and that information tends to flow from farm, to wholesale, to retail markets.asymmetric price transmission, vertical price transmission, error correction, thresholds, pork markets, Demand and Price Analysis, Livestock Production/Industries,
Study of properties of high-field superconductors at elevated temperatures Final technical report, 27 Apr. - 26 Aug. 1966
Properties of high field superconductors at high temperatures - magnetization experiments on niobium and niobium compound
Study of properties of high field superconductors, ac field induced flux jumps Technical summary report, 21 Jun. 1965 - 26 Apr. 1966
Magnetization experiments in superimposed dc and audiofrequency ac magnetic fields on cold worked NbTi alloy samples - ac field induced flux jump
Broughton Archipelago Clam Terrace Survey : final report
During a 1995 aerial video survey of the coastline
of Johnstone Strait, an unusual shoreline feature
was noted and termed “clam terraces” (inset)
because of the terrace-type morphology and the
apparent association with high clam productivity
on the sandflats. Typical alongshore lengths of the
terrace ridges are 20-50m, and across-shore widths
are typically 20-40m.
An area with an especially high density of clam
terraces was noted in the Broughton Archipelago,
between Broughton and Gilford Islands of
southeastern Queen Charlotte Strait. Clam terraces
in this area were inventoried from the aerial video
imagery to quantify their distribution. The terraces accounted for over 14 km of shoreline and
365 clam terraces were documented.
A three-day field survey by a coastal geomorphologist, archeologist and marine biologist was
conducted to document the features and determine their origin. Nine clam terraces were
surveyed. The field observations confirmed that: the ridges are comprised of boulder/cobblesized
material, ridge crests are typically in the range of 1-1.5m above chart datum, sandflats are
comprised almost entirely of shell fragments (barnacles and clams) and sandflats have very high
shellfish production. There are an abundance of shell middens in the area (over 175) suggesting
that the shellfish associated with the terraces were an important food source of aboriginal
peoples.
The origin of the ridges is unknown; they appear to be a relict feature in that they are not actively
being modified by present-day processes. The ridges may be a relict sea-ice feature, although the
mechanics of ridge formation is uncertain. Sand accumulates behind the ridge because the supply
rate of the shell fragments exceeds the dispersal rate in these low energy environments.
The high density areas of clam terraces correspond to high density areas of shell middens, and it
is probable that the clam terraces were subjected to some degree of modification by aboriginal
shellfish gatherers over the thousands of years of occupation in the region. (Document contains 39 pages
Thermal conductive connection and method of making same Patent
Thermal conductive, electrically insulated cleavable adhesive connection between electronic module and heat sin
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