32,022 research outputs found
Quantification of propidium iodide delivery with millisecond electric pulses: A model study
A model study of propidium iodide delivery with millisecond electric pulses
is presented; this work is a companion of the experimental efforts by Sadik et
al. [1]. Both membrane permeabilization and delivery are examined with respect
to six extra-cellular conductivities. The transmembrane potential of the
permeabilized regions exhibits a consistent value, which corresponds to a
bifurcation point in the pore-radius-potential relation. Both the pore area
density and membrane conductance increase with an increasing extra-cellular
conductivity. On the other hand, the inverse correlation between propidium
iodide delivery and extra-cellular conductivity as observed in the experiments
is quantitatively captured by the model. This agreement confirms that this
behavior is primarily mediated by electrophoretic transport during the pulse.
The results suggest that electrophoresis is important even for the delivery of
small molecules such as propidium iodide. The direct comparison between model
prediction and experimental data presented in this work helps validate the
former as a robust predictive tool for the study of electroporation
Component selection and smoothing in multivariate nonparametric regression
We propose a new method for model selection and model fitting in multivariate
nonparametric regression models, in the framework of smoothing spline ANOVA.
The ``COSSO'' is a method of regularization with the penalty functional being
the sum of component norms, instead of the squared norm employed in the
traditional smoothing spline method. The COSSO provides a unified framework for
several recent proposals for model selection in linear models and smoothing
spline ANOVA models. Theoretical properties, such as the existence and the rate
of convergence of the COSSO estimator, are studied. In the special case of a
tensor product design with periodic functions, a detailed analysis reveals that
the COSSO does model selection by applying a novel soft thresholding type
operation to the function components. We give an equivalent formulation of the
COSSO estimator which leads naturally to an iterative algorithm. We compare the
COSSO with MARS, a popular method that builds functional ANOVA models, in
simulations and real examples. The COSSO method can be extended to
classification problems and we compare its performance with those of a number
of machine learning algorithms on real datasets. The COSSO gives very
competitive performance in these studies.Comment: Published at http://dx.doi.org/10.1214/009053606000000722 in the
Annals of Statistics (http://www.imstat.org/aos/) by the Institute of
Mathematical Statistics (http://www.imstat.org
Exploring Extended Scalar Sectors with Di-Higgs Signals: A Higgs EFT Perspective
We consider extended scalar sectors of the Standard Model as
ultraviolet-complete motivations for studying the effective Higgs
self-interaction operators of the Standard Model effective field theory. We
investigate all motivated heavy scalar models which generate the dimension-6
effective operator, , at tree level and proceed to identify the full set
of tree-level dimension-six operators by integrating out the heavy scalars. Of
seven models which generate at tree level only two, quadruplets of
hypercharge and , generate only this operator. Next we perform
global fits to constrain relevant Wilson coefficients from the LHC single Higgs
measurements as well as the electroweak oblique parameters and . We find
that the parameter puts very strong constraints on the Wilson coefficient
of the operator in the triplet and quadruplet models, while the singlet
and doublet models could still have Higgs self-couplings which deviate
significantly from the standard model prediction. To determine the extent to
which the operator could be constrained, we study the dihiggs
signatures at the future 100 TeV collider and explore future sensitivity of
this operator. Projected onto the Higgs potential parameters of the extended
scalar sectors, with ab luminosity data we will be able to explore
the Higgs potential parameters in all seven models.Comment: 25 pages, 11 figures, 6 tables; version 3: match the JHEP published
versio
- β¦