1,205 research outputs found
CD44 Staining of Cancer Stem-Like Cells Is Influenced by Down-Regulation of CD44 Variant Isoforms and Up-Regulation of the Standard CD44 Isoform in the Population of Cells That Have Undergone Epithelial-to-Mesenchymal Transition
PMCID: PMC3577706This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Red Dog, Blue Dog, Yellow Dog: How Democrats Can Use Strategic Communications to Attract Republican and Conservative Voters
In recent election cycles, a rightward shift among white Southerners, and in some cases the loss of African-American supporters through racial redistricting, turned many long-held Democratic districts in the South red. Kentucky is an excellent example of this shift in voting behavior. Even though registered Democrats outnumber Republicans, the GOP controls the Governor\u27s mansion, most other statewide elected offices, both chamber of the state legislature, and all but one of Kentucky\u27s congressional seats. To win back those seats, Democrats in states like Kentucky will need to appeal to conservative voters. Unfortunately, little scholarly research directly addresses the practical question they need to answer: How can Democratic candidates attract right-leaning voters without sacrificing their credibility among voters on the left? On the basis of survey research conducted in Kentucky\u27s 6th Congressional district during the 2018 midterm election, this paper argues that conservative voters respond positively to some crossover messaging from Democratic candidates, particular with respect to social issues
Cladocera of Des Moines and Vicinity
This investigation was begun in April, 1901 and collections were made at various intervals during that spring. During the summer of 1901 eight or nine weeks were spent in collecting and identifying specimens. Again in the summer of 1902 the work was taken up for about five weeks and during the early part of the summer of 1903 further collections were made. At odd times during all this period new specimens have been noted as they were found in material collected for work in the Drake Zoological Laboratories
Unified Interacting Quark Stars in Regularized 4D Einstein Gauss-Bonnet Gravity
Since the derivation of a well-defined limit for 4D Einstein
Gauss-Bonnet (4DEGB) gravity coupled to a scalar field, there has been interest
in testing it as an alternative to Einstein's general theory of relativity.
Using the Tolman-Oppenheimer-Volkoff (TOV) equations modified for 4DEGB
gravity, we model the stellar structure of quark stars using a novel
interacting quark matter equation of state. We find that increasing the
Gauss-Bonnet coupling constant or the interaction parameter
both tend to increase the mass-radius profiles of quark stars described by this
theory, allowing a given central pressure to support larger quark stars in
general. These results logically extend to cases where , in which
increasing the magnitude of the interaction effects instead diminishes masses
and radii. We also analytically identify a critical central pressure in both
regimes, below which no quark star solutions exist due to the pressure function
having no roots. Most interestingly, we find that quark stars can exist below
the general relativistic Buchdahl bound and Schwarzschild radius , due to
the lack of a mass gap between black holes and compact stars in 4DEGB. Even for
small well within current observational constraints, we find that
quark star solutions in this theory can describe Extreme Compact Objects
(ECOs), objects whose radii are smaller than what is allowed by general
relativity
Light Scattering from Nonequilibrium Concentration Fluctuations in a Polymer solution
We have performed light-scattering measurements in dilute and semidilute
polymer solutions of polystyrene in toluene when subjected to stationary
temperature gradients. Five solutions with concentrations below and one
solution with a concentration above the overlap concentration were
investigated. The experiments confirm the presence of long-range nonequilibrium
concentration fluctuations which are proportional to , where
is the applied temperature gradient and is the wave number of
the fluctuations. In addition, we demonstrate that the strength of the
nonequilibrium concentration fluctuations, observed in the dilute and
semidilute solution regime, agrees with theoretical values calculated from
fluctuating hydrodynamics. Further theoretical and experimental work will be
needed to understand nonequilibrium fluctuations in polymer solutions at higher
concentrations.Comment: revtex, 16 pages, 7 figures. J. Chem. Phys., to appea
Ab-initio study of structure and dynamics properties of crystalline ice
We investigated the structural and dynamical properties of a tetrahedrally
coordinated crystalline ice from first principles based on density functional
theory within the generalized gradient approximation with the projected
augmented wave method. First, we report the structural behaviour of ice at
finite temperatures based on the analysis of radial distribution functions
obtained by molecular dynamics simulations. The results show how the ordering
of the hydrogen bonding breaks down in the tetrahedral network of ice with
entropy increase in agreement with the neutron diffraction data. We also
calculated the phonon spectra of ice in a 3x1x1 supercell by using the direct
method. So far, due to the direct method used in this calculation, the phonon
spectra is obtained without taking into account the effect of polarization
arising from dipole-dipole interactions of water molecules which is expected to
yield the splitting of longitudinal and transverse optic modes at the
Gamma-point. The calculated longitudinal acoustic velocities from the initial
slopes of the acoustic mode is in a reasonable agreement with the neutron
scatering data. The analysis of the vibrational density of states shows the
existence of a boson peak at low energy of translational region a
characteristic common to amorphous systems.Comment: International symposium on structure and dynamics of heterogeneous
system SDHS'0
Bistability of the Nuclear Polarisation created through optical pumping in InGaAs Quantum Dots
We show that optical pumping of electron spins in individual InGaAs quantum
dots leads to strong nuclear polarisation that we measure via the Overhauser
shift (OHS) in magneto-photoluminescence experiments between 0 and 4T. We find
a strongly non-monotonous dependence of the OHS on the applied magnetic field,
with a maximum nuclear polarisation of 40% for intermediate magnetic fields. We
observe that the OHS is larger for nuclear fields anti-parallel to the external
field than in the parallel configuration. A bistability in the dependence of
the OHS on the spin polarization of the optically injected electrons is found.
All our findings are qualitatively understood with a model based on a simple
perturbative approach.Comment: Phys Rev B (in press
The use of complete-case and multiple imputation-based analyses in molecular epidemiology studies that assess interaction effects
Abstract Background In molecular epidemiology studies biospecimen data are collected, often with the purpose of evaluating the synergistic role between a biomarker and another feature on an outcome. Typically, biomarker data are collected on only a proportion of subjects eligible for study, leading to a missing data problem. Missing data methods, however, are not customarily incorporated into analyses. Instead, complete-case (CC) analyses are performed, which can result in biased and inefficient estimates. Methods Through simulations, we characterized the performance of CC methods when interaction effects are estimated. We also investigated whether standard multiple imputation (MI) could improve estimation over CC methods when the data are not missing at random (NMAR) and auxiliary information may or may not exist. Results CC analyses were shown to result in considerable bias and efficiency loss. While MI reduced bias and increased efficiency over CC methods under specific conditions, it too resulted in biased estimates depending on the strength of the auxiliary data available and the nature of the missingness. In particular, CC performed better than MI when extreme values of the covariate were more likely to be missing, while MI outperformed CC when missingness of the covariate related to both the covariate and outcome. MI always improved performance when strong auxiliary data were available. In a real study, MI estimates of interaction effects were attenuated relative to those from a CC approach. Conclusions Our findings suggest the importance of incorporating missing data methods into the analysis. If the data are MAR, standard MI is a reasonable method. Auxiliary variables may make this assumption more reasonable even if the data are NMAR. Under NMAR we emphasize caution when using standard MI and recommend it over CC only when strong auxiliary data are available. MI, with the missing data mechanism specified, is an alternative when the data are NMAR. In all cases, it is recommended to take advantage of MI's ability to account for the uncertainty of these assumptions
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