523 research outputs found
Inflammatory and oxidative stress markers associated with decreased cervical length in pregnancy
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/134275/1/aji12545_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/134275/2/aji12545.pd
Gaugephobic Higgs Signals at the LHC
The Gaugephobic Higgs model provides an interpolation between three different
models of electroweak symmetry breaking: Higgsless models, Randall-Sundrum
models, and the Standard Model. At parameter points between the extremes,
Standard Model Higgs signals are present at reduced rates, and Higgsless
Kaluza-Klein excitations are present with shifted masses and couplings, as well
as signals from exotic quarks necessary to protect the Zbb coupling. Using a
new implementation of the model in SHERPA, we show the LHC signals which
differentiate the generic Gaugephobic Higgs model from its limiting cases.
These are all signals involving a Higgs coupling to a Kaluza-Klein gauge boson
or quark. We identify the clean signal mediated by a
Kaluza-Klein W, which can be present at large rates and is enhanced for even
Kaluza-Klein numbers. Due to the very hard lepton coming from the W decay, this
signature has little background, and provides a better discovery channel for
the Higgs than any of the Standard Model modes, over its entire mass range. A
Higgs radiated from new heavy quarks also has large rates, but is much less
promising due to very high multiplicity final states.Comment: 16 pages, 8 figure
Associations between repeated ultrasound measures of fetal growth and biomarkers of maternal oxidative stress and inflammation in pregnancy
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146468/1/aji13017_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146468/2/aji13017.pd
Phenomenology of the Little Higgs Model
We study the low energy phenomenology of the little Higgs model. We first
discuss the linearized effective theory of the "littlest Higgs model" and study
the low energy constraints on the model parameters. We identify sources of the
corrections to low energy observables, discuss model-dependent arbitrariness,
and outline some possible directions of extensions of the model in order to
evade the precision electroweak constraints. We then explore the characteristic
signatures to test the model in the current and future collider experiments. We
find that the LHC has great potential to discover the new SU(2) gauge bosons
and the possible new U(1) gauge boson to the multi-TeV mass scale. Other states
such as the colored vector-like quark T and doubly-charged Higgs boson Phi^{++}
may also provide interesting signals. At a linear collider, precision
measurements on the triple gauge boson couplings could be sensitive to the new
physics scale of a few TeV. We provide a comprehensive list of the linearized
interactions and vertices for the littlest Higgs model in the appendices.Comment: 43 pages, 6 figures; v2: discussion clarified, typos corrected; v3:
version to appear in PRD; v4: typos fixed in Feynman rule
Associations between mixtures of urinary phthalate metabolites with gestational age at delivery: a time to event analysis using summative phthalate risk scores
Abstract
Background
Preterm birth is a significant public health concern and exposure to phthalates has been shown to be associated with an increased odds of preterm birth. Even modest reductions in gestational age at delivery could entail morbid consequences for the neonate and analyzing data with this additional information may be useful. In the present analysis, we consider gestational age at delivery as our outcome of interest and examine associations with multiple phthalates.
Methods
Women were recruited early in pregnancy as part of a prospective, longitudinal birth cohort at the Brigham and Women’s Hospital in Boston, Massachusetts. Urine samples were collected at up to four time points during gestation for urinary phthalate metabolite measurement, and birth outcomes were recorded at delivery. From this population, we selected all 130 cases of preterm birth (< 37 weeks of gestation) as well as 352 random controls. We conducted analysis with both geometric average of the exposure concentrations across the first three visits as well as using repeated measures of the exposure. Two different time to event models were used to examine associations between nine urinary phthalate metabolite concentrations and time to delivery. Two different approaches to constructing a summative phthalate risk score were also considered.
Results
The single-pollutant analysis using a Cox proportional hazards model showed the strongest association with a hazard ratio (HR) of 1.21 (95% confidence interval (CI): 1.09, 1.33) per interquartile range (IQR) change in average log-transformed mono-2-ethyl-5-carboxypentyl phthalate (MECPP) concentration. Using the accelerated failure time model, we observed a 1.19% (95% CI: 0.26, 2.11%) decrease in gestational age in association with an IQR change in average log-transformed MECPP. We next examined associations with an environmental risk score (ERS). The fourth quartile of ERS was significantly associated with a HR of 1.44 (95% CI: 1.19, 1.75) and a reduction of 2.55% (95% CI: 0.76, 4.30%) in time to delivery (in days) compared to the first quartile.
Conclusions
On average, pregnant women with higher urinary metabolite concentrations of individual phthalates have shorter time to delivery. The strength of the observed associations are amplified with the risk scores when compared to individual pollutants.https://deepblue.lib.umich.edu/bitstream/2027.42/144517/1/12940_2018_Article_400.pd
Initial determination of the spins of the gluino and squarks at LHC
In principle particle spins can be measured from their production cross
sections once their mass is approximately known. The method works in practice
because spins are quantized and cross sections depend strongly on spins. It can
be used to determine, for example, the spin of the top quark. Direct
application of this method to supersymmetric theories will have to overcome the
challenge of measuring mass at the LHC, which could require high statistics. In
this article, we propose a method of measuring the spins of the colored
superpatners by combining rate information for several channels and a set of
kinematical variables, without directly measuring their masses. We argue that
such a method could lead to an early determination of the spin of gluino and
squarks. This method can be applied to the measurement of spin of other new
physics particles and more general scenarios.Comment: 23 pages, 8 figures, minor change
Effects of genuine dimension-six Higgs operators
We systematically discuss the consequences of genuine dimension-six Higgs
operators. These operators are not subject to stringent constraints from
electroweak precision data. However, they can modify the couplings of the Higgs
boson to electroweak gauge bosons and, in particular, the Higgs
self-interactions. We study the sensitivity to which those couplings can be
probed at future \ee linear colliders in the sub-TeV and in the multi-TeV
range. We find that for GeV with a luminosity of 1 ab the
anomalous and couplings may be probed to about the 0.01 level, and
the anomalous coupling to about the 0.1 level.Comment: 21 pages, 17 figures; typos corrected and references adde
A Hierarchical Integrative Group LASSO (HiGLASSO) Framework for Analyzing Environmental Mixtures
Environmental health studies are increasingly measuring multiple pollutants
to characterize the joint health effects attributable to exposure mixtures.
However, the underlying dose-response relationship between toxicants and health
outcomes of interest may be highly nonlinear, with possible nonlinear
interaction effects. Existing penalized regression methods that account for
exposure interactions either cannot accommodate nonlinear interactions while
maintaining strong heredity or are computationally unstable in applications
with limited sample size. In this paper, we propose a general shrinkage and
selection framework to identify noteworthy nonlinear main and interaction
effects among a set of exposures. We design hierarchical integrative group
LASSO (HiGLASSO) to (a) impose strong heredity constraints on two-way
interaction effects (hierarchical), (b) incorporate adaptive weights without
necessitating initial coefficient estimates (integrative), and (c) induce
sparsity for variable selection while respecting group structure (group LASSO).
We prove sparsistency of the proposed method and apply HiGLASSO to an
environmental toxicants dataset from the LIFECODES birth cohort, where the
investigators are interested in understanding the joint effects of 21 urinary
toxicant biomarkers on urinary 8-isoprostane, a measure of oxidative stress. An
implementation of HiGLASSO is available in the higlasso R package, accessible
through the Comprehensive R Archive Network.Comment: 29 pages, 6 figure
A novel HIV vaccine adjuvanted by IC31 induces robust and persistent humoral and cellular immunity.
The HIV vaccine strategy that, to date, generated immune protection consisted of a prime-boost regimen using a canarypox vector and an HIV envelope protein with alum, as shown in the RV144 trial. Since the efficacy was weak, and previous HIV vaccine trials designed to generate antibody responses failed, we hypothesized that generation of T cell responses would result in improved protection. Thus, we tested the immunogenicity of a similar envelope-based vaccine using a mouse model, with two modifications: a clade C CN54gp140 HIV envelope protein was adjuvanted by the TLR9 agonist IC31®, and the viral vector was the vaccinia strain NYVAC-CN54 expressing HIV envelope gp120. The use of IC31® facilitated immunoglobulin isotype switching, leading to the production of Env-specific IgG2a, as compared to protein with alum alone. Boosting with NYVAC-CN54 resulted in the generation of more robust Th1 T cell responses. Moreover, gp140 prime with IC31® and alum followed by NYVAC-CN54 boost resulted in the formation and persistence of central and effector memory populations in the spleen and an effector memory population in the gut. Our data suggest that this regimen is promising and could improve the protection rate by eliciting strong and long-lasting humoral and cellular immune responses
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