174 research outputs found
Deepening Partisan-Identity Polarization in the US: A Content Analysis of Major Party Platforms, 1980-2016
This thesis examines Democratic and Republican party platforms over the 1980-2016 period in a content analysis to test claims of partisanship increasing on identity lines in American politics. As a key issue facing democracies in recent years, polarization has coincided with challenges for democratic governance. Cases of âperniciousâ polarization that extend partisan rifts into social life, and especially those that feature an âexistentialâ or âformative rift\u27 dynamic as in the US case, may be prone to intractable partisan conflict and politics amenable to democratic erosion. The tensions may also create space for democracy enhancements. The findings of the content analysis offer support for increasing partisan-identity polarization in American politics in recent decades. Republican party platforms seem to increasingly reproduce a historical majoritarian appeal on religious-cultural or ethnic identity lines, in contrast to Democratic party platforms that likewise increasingly contest the meaning of âAmericanâ in more identitarian albeit inclusive in a multicultural sense of community and belonging
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Fabricating Superhydrophobic Surfaces with Solid Freeform Fabrication Tools
Superhydrophobic surfaces exhibit a range of properties such as large contact angle, low contact
angle hysteresis and decreased hydrodynamic drag. These properties make superhydrophobic
surfaces of fundamental and commercial interest as they can enable a wide variety of
applications including microfluidic components, biomedical devices, and micro-batteries.
Superhydrophobic behavior is achieved through a combination of the hydrophobicity of the
polymer and the roughness of the surface. We have used a commercially available multi-jet
modeling rapid prototyping machine to fabricate 3D objects where the superhydrophobic surface
is monolithic with the part. This approach was used to fabricate non-planar components with
novel structures including helical conduits and porous meshes. In addition, we have developed a
robotic dispensing tool that enables greater freedom of material selection. Both approaches have
been used to fabricate arrays of surface features with diameters below 175 microns and with
aspect ratios greater than 8:1. The fabrication and wetting properties of surfaces made using
these two techniques will be discussed.Mechanical Engineerin
Exploring the role of the α-carboxyphosphonate moiety in the HIV-RT activity of α-carboxy nucleoside phosphonates
As α-carboxy nucleoside phosphonates (α-CNPs) have demonstrated a novel mode of action of HIV-1 reverse transcriptase inhibition, structurally related derivatives were synthesized, namely the malonate 2, the unsaturated and saturated bisphosphonates 3 and 4, respectively and the amide 5. These compounds were evaluated for inhibition of HIV-1 reverse transcriptase in cell-free assays. The importance of the α-carboxy phosphonoacetic acid moiety for achieving reverse transcriptase inhibition, without the need for prior phosphorylation, was confirmed. The malonate derivative 2 was less active by two orders of magnitude than the original α-CNPs, while displaying the same pattern of kinetic behavior; interestingly the activity resides in the âLâ-enantiomer of 2, as seen with the earlier series of α-CNPs. A crystal structure with an RT/DNA complex at 2.95 Ă
resolution revealed the binding of the âLâ-enantiomer of 2, at the polymerase active site with a weaker metal ion chelation environment compared to 1a (T-α-CNP) which may explain the lower inhibitory activity of 2
Publishing patterns within the UK accounting and finance academic community
This study reports on publishing patterns in the UK and Irish accounting and finance academic community for the 2-year period 1998-1999 using the data contained in the BAR Research Register. It is found that the community has been growing modestly since 1991, with a doubling in the number of PhD-qualified staff (to 30%) and a reduction in the number with a professional qualification (from 81 to 58%). Nearly half of all outputs appear in other than academic journals. The mean number of publications is 1.76 per capita, with significantly more staff active in publishing than in 1991 (44% compared to 35%). However, only 17% publish in a subset of 60 'top' journals. Just over half of all articles are published in the core discipline journals, the rest appearing mainly in management, economics, sociology, education and IT journals. This may indicate a growing maturity in the disciplines, whereby applied research findings are flowing back into related foundation and business disciplines. Nearly two-thirds of academic articles are co-authored, with 25% of contributions coming from outside the community, indicating an openness to interdisciplinary collaboration, collaboration with overseas academics and collaboration with individuals in practice. The findings of this study will be of assistance to those making career decisions (either their own career or decisions involving other people's careers). They also raise awareness of the way in which the accounting and finance disciplines are developing
Strongly aligned gas-phase molecules at Free-Electron Lasers
We demonstrate a novel experimental implementation to strongly align
molecules at full repetition rates of free-electron lasers. We utilized the
available in-house laser system at the coherent x-ray imaging beamline at the
Linac Coherent Light Source. Chirped laser pulses, i. e., the direct output
from the regenerative amplifier of the Ti:Sa chirped pulse amplification laser
system, were used to strongly align 2,5-diiodothiophene molecules in a
molecular beam. The alignment laser pulses had pulse energies of a few mJ and a
pulse duration of 94 ps. A degree of alignment of
\left = 0.85 was measured, limited by the
intrinsic temperature of the molecular beam rather than by the available laser
system. With the general availability of synchronized chirped-pulse-amplified
near-infrared laser systems at short-wavelength laser facilities, our approach
allows for the universal preparation of molecules tightly fixed in space for
experiments with x-ray pulses.Comment: 10 pages, 5 figure
Combining biomarker and bulk compositional gradient analysis to assess reservoir connectivity
Author Posting. © The Author(s), 2010. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Organic Geochemistry 41 (2010): 812-821, doi:10.1016/j.orggeochem.2010.05.003.Hydraulic connectivity of petroleum reservoirs represents one of the biggest uncertainties for
both oil production and petroleum system studies. Here, a geochemical analysis involving bulk and
detailed measures of crude oil composition is shown to constrain connectivity more tightly than is
possible with conventional methods. Three crude oils collected from different depths in a single well
exhibit large gradients in viscosity, density, and asphaltene content. Crude oil samples are collected
with a wireline sampling tool providing samples from wellâdefined locations and relatively free of
contamination by drilling fluids; the known provenance of these samples minimizes uncertainties in the
subsequent analysis. The detailed chemical composition of almost the entire crude oil is determined by
use of comprehensive twoâdimensional gas chromatography (GCĂGC) to interrogate the nonpolar
fraction and negative ion electrospray ionization Fourier transform ion cyclotron resonance mass
spectrometry (ESI FTâICR MS) to interrogate the polar fraction. The simultaneous presence of 25â
norhopanes and mildly altered normal and isoprenoid alkanes is detected, suggesting that the reservoir
has experienced multiple charges and contains a mixture of oils biodegraded to different extents. The
gradient in asphaltene concentration is explained by an equilibrium model considering only gravitational
segregation of asphaltene nanoaggregates; this grading can be responsible for the observed variation in
viscosity. Combining these analyses yields a consistent picture of a connected reservoir in which the
observed viscosity variation originates from gravitational segregation of asphaltene nanoaggregates in a
crude oil with high asphaltene concentration resulting from multiple charges, including one charge that
suffered severe biodegradation. Observation of these gradients having appropriate magnitudes
suggests good reservoir connectivity with greater confidence than is possible with traditional techniques
alone.The mass spectrometry work was
supported by the NSF Division of Materials Research through DMRâ06â54118, and the State of Florida
The cdx Genes and Retinoic Acid Control the Positioning and Segmentation of the Zebrafish Pronephros
Kidney function depends on the nephron, which comprises a blood filter, a tubule that is subdivided into functionally distinct segments, and a collecting duct. How these regions arise during development is poorly understood. The zebrafish pronephros consists of two linear nephrons that develop from the intermediate mesoderm along the length of the trunk. Here we show that, contrary to current dogma, these nephrons possess multiple proximal and distal tubule domains that resemble the organization of the mammalian nephron. We examined whether pronephric segmentation is mediated by retinoic acid (RA) and the caudal (cdx) transcription factors, which are known regulators of segmental identity during development. Inhibition of RA signaling resulted in a loss of the proximal segments and an expansion of the distal segments, while exogenous RA treatment induced proximal segment fates at the expense of distal fates. Loss of cdx function caused abrogation of distal segments, a posterior shift in the position of the pronephros, and alterations in the expression boundaries of raldh2 and cyp26a1, which encode enzymes that synthesize and degrade RA, respectively. These results suggest that the cdx genes act to localize the activity of RA along the axis, thereby determining where the pronephros forms. Consistent with this, the pronephric-positioning defect and the loss of distal tubule fate were rescued in embryos doubly-deficient for cdx and RA. These findings reveal a novel link between the RA and cdx pathways and provide a model for how pronephric nephrons are segmented and positioned along the embryonic axis
Design and synthesis of alpha-carboxy nucleoside phosphonate analogues and evaluation as HIV-1 reverse transcriptase-targeting agents
The synthesis of the first series of a new class of nucleoside phosphonate analogues is described. Addition of a carboxyl group at the α position of carbocyclic nucleoside phosphonate analogues leads to a novel class of potent HIV reverse transcriptase (RT) inhibitors, α-carboxy nucleoside phosphonates (α-CNPs). Key steps in the synthesis of the compounds are Rh-catalyzed OâH insertion and Pd-catalyzed allylation reactions. In cell-free assays, the final products are markedly inhibitory against HIV RT and do not require phosphorylation to exhibit anti-RT activity, which indicates that the α-carboxyphosphonate function is efficiently recognized by HIV RT as a triphosphate entity, an unprecedented property of nucleoside monophosph(on)ates
The Shapes of Flux Domains in the Intermediate State of Type-I Superconductors
In the intermediate state of a thin type-I superconductor magnetic flux
penetrates in a disordered set of highly branched and fingered macroscopic
domains. To understand these shapes, we study in detail a recently proposed
"current-loop" (CL) model that models the intermediate state as a collection of
tense current ribbons flowing along the superconducting-normal interfaces and
subject to the constraint of global flux conservation. The validity of this
model is tested through a detailed reanalysis of Landau's original conformal
mapping treatment of the laminar state, in which the superconductor-normal
interfaces are flared within the slab, and of a closely-related straight-lamina
model. A simplified dynamical model is described that elucidates the nature of
possible shape instabilities of flux stripes and stripe arrays, and numerical
studies of the highly nonlinear regime of those instabilities demonstrate
patterns like those seen experimentally. Of particular interest is the buckling
instability commonly seen in the intermediate state. The free-boundary approach
further allows for a calculation of the elastic properties of the laminar
state, which closely resembles that of smectic liquid crystals. We suggest
several new experiments to explore of flux domain shape instabilities,
including an Eckhaus instability induced by changing the out-of-plane magnetic
field, and an analog of the Helfrich-Hurault instability of smectics induced by
an in-plane field.Comment: 23 pages, 22 bitmapped postscript figures, RevTex 3.0, submitted to
Phys. Rev. B. Higher resolution figures may be obtained by contacting the
author
X-ray diffractive imaging of controlled gas-phase molecules: Toward imaging of dynamics in the molecular frame
We report experimental results on the diffractive imaging of
three-dimensionally aligned 2,5-diiodothiophene molecules. The molecules were
aligned by chirped near-infrared laser pulses, and their structure was probed
at a photon energy of 9.5 keV () provided by the
Linac Coherent Light Source. Diffracted photons were recorded on the CSPAD
detector and a two-dimensional diffraction pattern of the equilibrium structure
of 2,5-diiodothiophene was recorded. The retrieved distance between the two
iodine atoms agrees with the quantum-chemically calculated molecular structure
to within 5 %. The experimental approach allows for the imaging of intrinsic
molecular dynamics in the molecular frame, albeit this requires more
experimental data which should be readily available at upcoming
high-repetition-rate facilities
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