1,158 research outputs found
Ethanol: Implications for Rural Communities
This paper presents an overview of the U.S. ethanol industry, its location, and the public policy umbrella that supports its growth. Then the paper analyzes what happens when a county adds an ethanol plant, demonstrates what must be done to modify input-output models to capture those effects realistically, and applies the approach to proposed plants in three counties.Resource /Energy Economics and Policy,
Aspects of supersymmetry in multiple membrane theories
PhDThis thesis consists of two parts. In the rst part we investigate the worldvolume
supersymmetry algebra of multiple membrane theories. We begin with a description
of M-theory branes and their intersections from the perspective of spacetime
and worldvolume supersymmetry algebras. We then provide an overview of the
recent work on multiple M2-branes focusing on the Bagger-Lambert theory and
its relation to the Nambu-Poisson M5-brane and the ABJM theory. The worldvolume
supersymmetry algebras of these theories are explicitly calculated and the
charges interpreted in terms of spacetime intersections of M-branes.
The second part of the thesis looks at l3
p corrections to the supersymmetry
transformations of the Bagger-Lambert theory. We begin with a review of the
dNS duality transformation which allows a gauge eld to be dualised to a scalar
eld in 2+1 dimensions. Applying this duality to 02 terms of the non-abelian
D2-brane theory gives rise to the l3
p corrections of the Lorentzian Bagger-Lambert
theory. We then apply this duality transformation to the 02 corrections of the
D2-brane supersymmetry transformations. For the `abelian' Bagger-Lambert theory
we are able to uniquely determine the l3
p corrections to the supersymmetry
transformations of the scalar and fermion elds. Generalising to the `non-abelian'
Bagger-Lambert theory we are able to determine the l3
p correction to the supersymmetry
transformation of the fermion eld. Along the way make a number of
observations relating to the implementation of the dNS duality transformation at
the level of supersymmetry transformations
Practical trapped-ion protocols for universal qudit-based quantum computing
The notion of universal quantum computation can be generalized to multi-level
qudits, which offer advantages in resource usage and algorithmic efficiencies.
Trapped ions, which are pristine and well-controlled quantum systems, offer an
ideal platform to develop qudit-based quantum information processing. Previous
work has not fully explored the practicality of implementing trapped-ion qudits
accounting for known experimental error sources. Here, we describe a universal
set of protocols for state preparation, single-qudit gates, a new
generalization of the M\o{}lmer-S\o{}rensen gate for two-qudit gates, and a
measurement scheme which utilizes shelving to a meta-stable state. We
numerically simulate known sources of error from previous trapped ion
experiments, and show that there are no fundamental limitations to achieving
fidelities above for three-level qudits encoded in
ions. Our methods are extensible to higher-dimensional
qudits, and our measurement and single-qudit gate protocols can achieve
fidelities for five-level qudits. We identify avenues to further
decrease errors in future work. Our results suggest that three-level trapped
ion qudits will be a useful technology for quantum information processing
Adverse pregnancy and perinatal outcomes associated with Mycoplasma genitalium: systematic review and meta-analysis.
OBJECTIVE
To examine associations between Mycoplasma genitalium infection during pregnancy and adverse outcomes.
METHODS
We did a systematic review of observational studies. We searched Medline, EMBASE, the Cochrane Library and CINAHL up to 11 August 2021. Studies were included if they compared preterm birth, spontaneous abortion, premature rupture of membranes, low birth weight or perinatal death between women with and without M. genitalium. Two reviewers independently assessed articles for inclusion and extracted data. We used random-effects meta-analysis to estimate summary ORs and adjusted ORs, with 95% CIs, where appropriate. Risk of bias was assessed using established checklists.
RESULTS
We identified 116 records and included 10 studies. Women with M. genitalium were more likely to experience preterm birth in univariable analyses (summary unadjusted OR 1.91, 95% CI 1.29 to 2.81, I2=0%, 7 studies). The combined adjusted OR was 2.34 (95% CI 1.17 to 4.71, I2=0%, 2 studies). For spontaneous abortion, the summary unadjusted OR was 1.00 (95% CI 0.53 to 1.89, I2=0%, 6 studies). The adjusted OR in one case-control study was 0.9 (95% CI 0.2 to 3.8). Unadjusted ORs for premature rupture of membranes were 7.62 (95% CI 0.40 to 145.86, 1 study) and for low birth weight 1.07 (95% CI 0.02 to 10.39, 1 study). For perinatal death, the unadjusted OR was 1.07 (95% CI 0.49 to 2.36) in one case-control and 38.42 (95% CI 1.45 to 1021.43) in one cohort study. These two ORs were not combined, owing to heterogeneity. The greatest risk of bias was the failure in most studies to control for confounding.
CONCLUSION
M. genitalium might be associated with an increased risk of preterm birth. Further prospective studies, with adequate control for confounding, are needed to understand the role of M. genitalium in adverse pregnancy outcomes. There is insufficient evidence to indicate routine testing and treatment of asymptomatic M. genitalium in pregnancy.
PROSPERO REGISTRATION NUMBER
CRD42016050962
Electroweak Precision Constraints on the Littlest Higgs Model with T Parity
We compute the leading corrections to the properties of W and Z bosons
induced at the one-loop level in the SU(5)/SO(5) Littlest Higgs model with T
parity, and perform a global fit to precision electroweak data to determine the
constraints on the model parameters. We find that a large part of the model
parameter space is consistent with data. Values of the symmetry breaking scale
as low as 500 GeV are allowed, indicating that no significant fine tuning in
the Higgs potential is required. We identify a region within the allowed
parameter space in which the lightest T-odd particle, the partner of the
hypercharge gauge boson, has the correct relic abundance to play the role of
dark matter. In addition, we find that a consistent fit to data can be obtained
for large values of the Higgs mass, up to 800 GeV, due to the possibility of a
partial cancellation between the contributions to the T parameter from Higgs
loops and new physics.Comment: 23 pages, 9 figures. Minor correction
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