160 research outputs found
Zu Zu Rag
A human figure in a star-covered outfit with the title located at the tophttps://scholarsjunction.msstate.edu/cht-sheet-music/13976/thumbnail.jp
Iterative ('Turbo') Multiuser Detectors For Impulse Radio Systems
In recent years, there has been a growing interest in multiple access
communication systems that spread their transmitted energy over very large
bandwidths. These systems, which are referred to as ultra wide-band (UWB)
systems, have various advantages over narrow-band and conventional wide-band
systems. The importance of multiuser detection for achieving high data or low
bit error rates in these systems has already been established in several
studies. This paper presents iterative ('turbo') multiuser detection for
impulse radio (IR) UWB systems over multipath channels. While this approach is
demonstrated for UWB signals, it can also be used in other systems that use
similar types of signaling. When applied to the type of signals used by UWB
systems, the complexity of the proposed detector can be quite low. Also, two
very low complexity implementations of the iterative multiuser detection scheme
are proposed based on Gaussian approximation and soft interference
cancellation. The performance of these detectors is assessed using simulations
that demonstrate their favorable properties.Comment: To appear in IEEE Transactions on Wireless Communication
Web platform vs in-person genetic counselor for return of carrier results from exome sequencing a randomized clinical trial
© 2018 American Medical Association. All rights reserved. IMPORTANCE A critical bottleneck in clinical genomics is the mismatch between large volumes of results and the availability of knowledgeable professionals to return them. OBJECTIVE To test whether a web-based platform is noninferior to a genetic counselor for educating patients about their carrier results from exome sequencing. DESIGN, SETTING, AND PARTICIPANTS A randomized noninferiority trial conducted in a longitudinal sequencing cohort at the National Institutes of Health from February 5, 2014, to December 16, 2016, was used to compare the web-based platform with a genetic counselor. Among the 571 eligible participants, 1 to 7 heterozygous variants were identified in genes that cause a phenotype that is recessively inherited. Surveys were administered after cohort enrollment, immediately following trial education, and 1 month and 6 months later to primarily healthy postreproductive participants who expressed interest in learning their carrier results. Both intention-to-treat and per-protocol analyses were applied. INTERVENTIONS A web-based platform that integrated education on carrier results with personal test results was designed to directly parallel disclosure education by a genetic counselor. The sessions took a mean (SD) time of 21 (10.6), and 27 (9.3) minutes, respectively. MAIN OUTCOMES AND MEASURES The primary outcomes and noninferiority margins (dNI) were knowledge (0 to 8, dNI = -1), test-specific distress (0 to 30, dNI = +1), and decisional conflict (15 to 75, dNI = +6). RESULTS After 462 participants (80.9%) provided consent and were randomized, all but 3 participants (n = 459) completed surveys following education and counseling; 398 (86.1%) completed 1-month surveys and 392 (84.8%) completed 6-month surveys. Participants were predominantly well-educated, non-Hispanic white, married parents; mean (SD) age was 63 (63.1) years and 246 (53.6%) were men. The web platform was noninferior to the genetic counselor on outcomes assessed at 1 and 6 months: knowledge (mean group difference, -0.18; lower limit of 97.5% CI, -0.63; dNI = -1), test-specific distress (median group difference, 0; upper limit of 97.5% CI, 0; dNI = +1), and decisional conflict about choosing to learn results (mean group difference, 1.18; upper limit of 97.5% CI, 2.66; dNI = +6). There were no significant differences between the genetic counselors and web-based platform detected between modes of education delivery in disclosure rates to spouses (151 vs 159; relative risk [RR], 1.04; 95% CI, 0.64-1.69; P > .99), children (103 vs 117; RR, 1.07; 95% CI, 0.85-1.36; P = .59), or siblings (91 vs 78; RR, 1.17; 95% CI, 0.94-1.46; P = .18). CONCLUSIONS AND RELEVANCE This trial demonstrates noninferiority of web-based return of carrier results among postreproductive, mostly healthy adults. Replication studies among younger and more diverse populations are needed to establish generalizability. Yet return of results via a web-based platform may be sufficient for subsets of test results, reserving genetic counselors for return of results with a greater health threat
Exotic leptoquarks from superstring derived models
The H1 and ZEUS collaborations have recently reported a significant excess of
events at high in positron-proton collisions. While there exists
insufficient data to conclusively determine the origin of this excess, one
possibility is that it is due to a new leptoquark at mass scale around 200 GeV.
We examine the type of leptoquark states that exist in superstring derived
standard-like models, and show that, while these models may contain the
standard leptoquark states which exist in Grand Unified Theories, they also
generically contain new and exotic leptoquark states with fractional lepton
number, . In contrast to the traditional GUT-type leptoquark states,
the couplings of the exotic leptoquarks to the Standard Model states are
generated after the breaking of . This important feature of the
exotic leptoquark states may result in local discrete symmetries which forbid
some of the undesired leptoquark couplings. We examine these couplings in
several models and study the phenomenological implications. The flavor
symmetries of the superstring models are found to naturally suppress leptoquark
flavor changing processes.Comment: 28 pages. Standard Latex. Final version to appear in Nuclear Physics
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Leptonic CP Violation in Supersymmetric Standard Model
We point out the possibility of spontaneous and hard CP-violation in the
scalar potential of R-parity broken supersymmetric Standard Model. The
existence of spontaneous CP-violation depends crucially on the R-parity
breaking terms in the superpotential and, in addition, on the choice of the
soft supersymmetry breaking terms. Unlike in theories with R-parity
conservation, it is natural, in the context of the present model, for the
sneutrinos to acquire (complex) vacuum expectation values. In the context of
this model we examine here the global implications, like the strength of the
CP-violating interactions and the neutrino masses.Comment: REVTEX, 15 page
Cosmological constraints on R-parity violation from neutrino decay
If the neutrino mass is non-zero, as hinted by several experiments, then
R-parity-violating supersymmetric Yukawa couplings can drive a heavy neutrino
decay into lighter states. The heavy neutrino may either decay radiatively into
a lighter neutrino, or it may decay into three light neutrinos through a
Z-mediated penguin. For a given mass of the decaying neutrino, we calculate its
lifetime for the various modes, each mode requiring certain pairs of
R-parity-violating couplings be non-zero. We then check whether the calculated
lifetimes fall in zones allowed or excluded by cosmological requirements. For
the latter case, we derive stringent new constraints on the corresponding
products of R-parity-violating couplings for given values of the decaying
neutrino mass.Comment: 13 pages, Latex, uses axodraw.sty; version to appear in Physical
Review
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Automatic Alignment of the Advanced Radiographic Capability for the National Ignition Facility
Recycling universe
If the effective cosmological constant is non-zero, our observable universe
may enter a stage of exponential expansion. In such case, regions of it may
tunnel back to the false vacuum of an inflaton scalar field, and inflation with
a high expansion rate may resume in those regions. An ``ideal'' eternal
observer would then witness an infinite succession of cycles from false vacuum
to true, and back. Within each cycle, the entire history of a hot universe
would be replayed. If there were several minima of the inflaton potential, our
ideal observer would visit each one of these minima with a frequency which
depends on the shape of the potential. We generalize the formalism of
stochastic inflation to analyze the global structure of the universe when this
`recycling' process is taken into account.Comment: 43 pages, 10 figure
How generic is cosmic string formation in SUSY GUTs
We study cosmic string formation within supersymmetric grand unified
theories. We consider gauge groups having a rank between 4 and 8. We examine
all possible spontaneous symmetry breaking patterns from the GUT down to the
standard model gauge group. Assuming standard hybrid inflation, we select all
the models which can solve the GUT monopole problem, lead to baryogenesis after
inflation and are consistent with proton lifetime measurements. We conclude
that in all acceptable spontaneous symmetry breaking schemes, cosmic string
formation is unavoidable. The strings which form at the end of inflation have a
mass which is proportional to the inflationary scale. Sometimes, a second
network of strings form at a lower scale. Models based on gauge groups which
have rank greater than 6 can lead to more than one inflationary era; they all
end by cosmic string formation.Comment: 31 pages, Latex, submitted to PR
Inflation in Supersymmetric Unified Theories
We construct supersymmetric unified models which automatically lead to a
period of inflation. The models all involve a U(1) symmetry which does not
belong to the MSSM. We consider three different types of models depending on
whether this extra U(1) is the subgroup of a non abelian gauge group, is a U(1)
factor belonging to the visible sector or is a U(1) factor belonging to the
hidden sector. Depending on the structure of the unified theory, on the
spontaneous symmetry breaking pattern and on whether we have global or local
supersymmetry, inflation may be driven by the non-vanishing vacuum expectation
value of a F-term or by that of a D-term. In both scenarios cosmic strings form
at the end of inflation, and they have different properties in each model. Both
inflation and cosmic strings contribute to the CMBR temperature anisotropies.
We show that the strings contribute to the 's up to the level of 75 %.
Hence the contribution from strings to the CMBR and to the density
perturbations in the early Universe which lead to structure formation cannot be
neglected. We also discuss a very interesting class of models which involve a
gauge symmetry.Comment: 22 pages, uses Revte
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