6,584 research outputs found
The Big Swamp Bogie Man / music by George W. Meyer; words by Earle C. Jones
Cover: The World Magazine, Sunday, Sept. 19, 1909; Publisher: Jos. W. Stern and Co. (New York)https://egrove.olemiss.edu/sharris_b/1094/thumbnail.jp
Search for lepton flavor violating decays of a heavy neutral particle in p-pbar collisions at root(s)=1.8 TeV
We report on a search for a high mass, narrow width particle that decays
directly to e+mu, e+tau, or mu+tau. We use approximately 110 pb^-1 of data
collected with the Collider Detector at Fermilab from 1992 to 1995. No evidence
of lepton flavor violating decays is found. Limits are set on the production
and decay of sneutrinos with R-parity violating interactions.Comment: Figure 2 fixed. Reference 4 fixed. Minor changes to tex
Measurement of Resonance Parameters of Orbitally Excited Narrow B^0 Mesons
We report a measurement of resonance parameters of the orbitally excited
(L=1) narrow B^0 mesons in decays to B^{(*)+}\pi^- using 1.7/fb of data
collected by the CDF II detector at the Fermilab Tevatron. The mass and width
of the B^{*0}_2 state are measured to be m(B^{*0}_2) =
5740.2^{+1.7}_{-1.8}(stat.) ^{+0.9}_{-0.8}(syst.) MeV/c^2 and \Gamma(B^{*0}_2)
= 22.7^{+3.8}_{-3.2}(stat.) ^{+3.2}_{-10.2}(syst.) MeV/c^2. The mass difference
between the B^{*0}_2 and B^0_1 states is measured to be
14.9^{+2.2}_{-2.5}(stat.) ^{+1.2}_{-1.4}(syst.) MeV/c^2, resulting in a B^0_1
mass of 5725.3^{+1.6}_{-2.2}(stat.) ^{+1.4}_{-1.5}(syst.) MeV/c^2. This is
currently the most precise measurement of the masses of these states and the
first measurement of the B^{*0}_2 width.Comment: 7 pages, 1 figure, 1 table. Submitted to Phys.Rev.Let
Measurement of the fraction of t-tbar production via gluon-gluon fusion in p-pbar collisions at sqrt(s)=1.96 TeV
We present a measurement of the ratio of t-tbar production cross section via
gluon-gluon fusion to the total t-tbar production cross section in p-pbar
collisions at sqrt{s}=1.96 TeV at the Tevatron. Using a data sample with an
integrated luminosity of 955/pb recorded by the CDF II detector at Fermilab, we
select events based on the t-tbar decay to lepton+jets. Using an artificial
neural network technique we discriminate between t-tbar events produced via
q-qbar annihilation and gluon-gluon fusion, and find
Cf=(gg->ttbar)/(pp->ttbar)<0.33 at the 68% confidence level. This result is
combined with a previous measurement to obtain the most precise measurement of
this quantity, Cf=0.07+0.15-0.07.Comment: submitted to Phys. Rev.
Software Model Checking with Explicit Scheduler and Symbolic Threads
In many practical application domains, the software is organized into a set
of threads, whose activation is exclusive and controlled by a cooperative
scheduling policy: threads execute, without any interruption, until they either
terminate or yield the control explicitly to the scheduler. The formal
verification of such software poses significant challenges. On the one side,
each thread may have infinite state space, and might call for abstraction. On
the other side, the scheduling policy is often important for correctness, and
an approach based on abstracting the scheduler may result in loss of precision
and false positives. Unfortunately, the translation of the problem into a
purely sequential software model checking problem turns out to be highly
inefficient for the available technologies. We propose a software model
checking technique that exploits the intrinsic structure of these programs.
Each thread is translated into a separate sequential program and explored
symbolically with lazy abstraction, while the overall verification is
orchestrated by the direct execution of the scheduler. The approach is
optimized by filtering the exploration of the scheduler with the integration of
partial-order reduction. The technique, called ESST (Explicit Scheduler,
Symbolic Threads) has been implemented and experimentally evaluated on a
significant set of benchmarks. The results demonstrate that ESST technique is
way more effective than software model checking applied to the sequentialized
programs, and that partial-order reduction can lead to further performance
improvements.Comment: 40 pages, 10 figures, accepted for publication in journal of logical
methods in computer scienc
The WARPS survey: III. The discovery of an X-ray luminous galaxy cluster at z=0.833 and the impact of X-ray substructure on cluster abundance measurements
The WARPS team reviews the properties and history of discovery of
ClJ0152.7-1357, an X-ray luminous, rich cluster of galaxies at z=0.833. At L_X
= 8 x 10^44 h^(-2) erg/s (0.5-2.0 keV) ClJ0152.7-1357 is the most X-ray
luminous cluster known at redshifts z>0.55. The high X-ray luminosity of the
system suggests that massive clusters may begin to form at redshifts
considerably greater than unity. This scenario is supported by the high degree
of optical and X-ray substructure in ClJ0152.7-1357, which is similarly complex
as that of other X-ray selected distant clusters and consistent with the
picture of cluster formation by mass infall along large-scale filaments. X-ray
emission from ClJ0152.7-1357 was detected already in 1980 with the EINSTEIN
IPC. However, because the complex morphology of the emission caused its
significance to be underestimated, the corresponding source was not included in
the EMSS cluster sample and hence not previously identified. Simulations of the
EMSS source detection and selection procedure suggest a general bias of the
EMSS against X-ray luminous clusters with pronounced substructure. If highly
unrelaxed, merging clusters are common at high redshift, they could create a
bias in some samples as the morphological complexity of mergers may cause them
to fall below the flux limit of surveys that assume a unimodal spatial source
geometry. Conversely, the enhanced X-ray luminosity of mergers might cause them
to, temporarily, rise above the flux limit. Either effect could lead to
erroneous conclusions about the evolution of the comoving cluster space
density. A high fraction of morphologically complex clusters at high redshift
would also call into question the validity of cosmological studies that assume
that the systems under investigation are virialized.Comment: 17 pages, 7 figures; revised to focus on possible detection biases
caused by substructure in clusters; accepted for publication in ApJ; uses
emulateapj.sty; eps files of figures 1 and 2 can be obtained from
ftp://hubble.ifa.hawaii.edu/pub/ebeling/warp
Bridge distress caused by approach embankment settlement
Surtees Bridge, which carries the A66(T) over the River
Tees near Thornaby-on-Tees in the UK, has been
showing signs of distress that predate its opening in
1981. Subsequent investigations have shown that the
bridge distress is related to unexpectedly large
settlement of the eastern approach embankment.
Recent ground investigations prompted by a proposed
widening of the river crossing have produced many new
data on the alluvial deposits underlying the site, and
explain why embankment settlement was so much larger
than originally anticipated. Comparison of the
geotechnical parameters obtained from the original and
more recent ground investigations suggests that the
original investigation significantly underestimated the
thickness of an alluvial clay layer underlying the site, and
that its coefficient of consolidation was overestimated.
Settlement analyses using geotechnical data from the
original ground investigations predict moderate
embankment settlements occurring principally during
construction. Settlement analyses based on all the
available data predict far larger embankment
settlements occurring over extended time periods. The
latter analyses predict an embankment settlement
similar to that observed and of sufficient magnitude to
cause the observed lateral displacement of the bridge
due to lateral loading of its piled foundation
'Caught Between a Rock and a Hard Place': Anti-discrimination Legislation in the Liberal State and the Fate of the Australian Disability Discrimination Act
This article offers a critical analysis of some of the practical implications for disabled people of the Disability Discrimination Act of 1992. Specifically, it raises questions about politics and the role of the law as an instrument of social change?taking greater account of the interests of disabled people?on the one hand, and of the reliance of the social model of disability on a strategy based upon legal rights on the other. The article also suggests that the constraining effects of Australia's constitutional protections of rights and its federal system of government hinder the mildly progressive elements of the Disability Discrimination Act. To illustrate this, the paper employs empirical evidence to suggest that these effects have been exacerbated by the passage of the Human Rights Legislation Amendment Act in 1999
Amicable pairs and aliquot cycles for elliptic curves
An amicable pair for an elliptic curve E/Q is a pair of primes (p,q) of good
reduction for E satisfying #E(F_p) = q and #E(F_q) = p. In this paper we study
elliptic amicable pairs and analogously defined longer elliptic aliquot cycles.
We show that there exist elliptic curves with arbitrarily long aliqout cycles,
but that CM elliptic curves (with j not 0) have no aliqout cycles of length
greater than two. We give conjectural formulas for the frequency of amicable
pairs. For CM curves, the derivation of precise conjectural formulas involves a
detailed analysis of the values of the Grossencharacter evaluated at a prime
ideal P in End(E) having the property that #E(F_P) is prime. This is especially
intricate for the family of curves with j = 0.Comment: 53 page
The pharmaceutical use of permethrin: Sources and behavior during municipal sewage treatment
This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ 2010 Springer Science+Business Media, LLC.Permethrin entered use in the 1970s as an insecticide in a wide range of applications, including agriculture, horticultural, and forestry, and has since been restricted. In the 21st century, the presence of permethrin in the aquatic environment has been attributed to its use as a human and veterinary pharmaceutical, in particular as a pedeculicide, in addition to other uses, such as a moth-proofing agent. However, as a consequence of its toxicity to fish, sources of permethrin and its fate and behavior during wastewater treatment are topics of concern. This study has established that high overall removal of permethrin (approximately 90%) was achieved during wastewater treatment and that this was strongly dependent on the extent of biological degradation in secondary treatment, with more limited subsequent removal in tertiary treatment processes. Sources of permethrin in the catchment matched well with measured values in crude sewage and indicated that domestic use accounted for more than half of the load to the treatment works. However, removal may not be consistent enough to achieve the environmental quality standards now being derived in many countries even where tertiary treatment processes are applied.United Utilities PL
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