Kingmakers or Cheerleaders? Party Power and the Causal Effects of Endorsements

When parties make endorsements in primary elections, does the favored candidate receive a real boost in his or her vote share, or do parties simply pick the favorites who are already destined to win? To answer this question, we draw on two research designs aimed at isolating the causal effect of Democratic Party endorsements in California’s 2012 primary election. First, we conduct a survey experiment in which we randomly assign a party endorsement, holding all other aspects of a candidate’s background and policy positions constant. Second, we use a unique dataset to implement a regression discontinuity analysis of electoral trends by comparing the vote shares captured by candidates who barely won or barely lost the internal party endorsement contest. We find a constellation of evidence suggesting that endorsements do indeed matter, although this effect appears to be contingent upon the type of candidate and voter: endorsements matter most for candidates in their party’s mainstream, and for voters who identify with that party and for independents. The magnitude of their impact is dramatically smaller than might be estimated from research designs less attuned to recent advances in causal inference

A parallel-plate flow chamber to study initial cell adhesion on a nanofeatured surface

Cells in the human body come across many types of information, which they respond to. Both material chemistry and topography of the surface where they adhere have an effect on cell shape, proliferation, migration, and gene expression. It is possible to create surfaces with topography at the nanometric scale to allow observation of cell-topography interactions. Previous work has shown that 100-nm-diameter pits on a 300-nm pitch can have a marked effect in reducing the adhesion of rat fibroblasts in static cultures. In the present study, a flow of cell suspension was used to investigate cell adhesion onto nanopits in dynamic conditions, by means of a parallel-plate flow chamber. A flow chamber with inner nanotopography has been designed, which allows real-time observation of the flow over the nanopits. A nanopitted pattern was successfully embossed into polymethylmethacrylate to meet the required shape of the chamber. Dynamic cell adhesion after 1 h has been quantified and compared on flat and nanopitted polymethylmethacrylate substrates. The nanopits were seen to be significantly less adhesive than the flat substrates (p<0.001), which is coherent with previous observations of static cultures

Career-Related Issues in Secondary Schools: A Literature Review

The career counselor’s role over the past 100 years or so has evolved from being a placement tool in the industrial revolution to that of providing a more holistic approach to meeting both the career and personal concerns of individuals. More and more counselors are beginning to focus on the person as a whole, including values, interests, abilities, skills, and work-life experiences, as they counsel on career-related issues (Zunker, 2006). As a focus on human development and the whole person enters the counseling field, school counselors are faced with developing comprehensive school guidance systems that meet the needs of students throughout elementary and high school. These programs focus on the importance of career development throughout the lifespan rather than during only one period. Due to this increased importance on career development, a psycho-educational group aimed at addressing the needs and concerns of high school students is a much-needed intervention in the development of career concepts in students. Students are faced with making key career decisions in high school before many are equipped with the knowledge and maturity to make those decisions effectively

A procedure to analyze nonlinear density waves in Saturn's rings using several occultation profiles

Cassini radio science experiments have provided multiple occultation optical depth profiles of Saturn's rings that can be used in combination to analyze density waves. This paper establishes an accurate procedure of inversion of the wave profiles to reconstruct the wave kinematic parameters as a function of semi-major axis, in the nonlinear regime. This procedure is achieved from simulated data in the presence of realistic noise perturbations, to control the reconstruction error. By way of illustration we have applied our procedure to the Mimas 5:3 density wave. We were able to recover precisely the kinematic parameters from the radio experiment occultation data in most of the propagation region; a preliminary analysis of the pressure-corrected dispersion allowed us to determine new but still uncertain values for the opacity ($K\simeq 0.02$ cm$^2$/g) and velocity dispersion of ($c_o\simeq 0.6$ cm/s) in the wave region. Our procedure constitutes the first step in our planned analysis of the density waves of Saturn's rings. It is very accurate and efficient in the far-wave region. However, improvements are required within the first wavelength. The ways in which this method can be used to establish diagnostics of ring physics are outlined.Comment: 50 pages,13 figures, 2 tables. Published in Icarus

No apparent benefits of allonursing for recipient offspring and mothers in the cooperatively breeding meerkat.

Cooperative behaviours by definition are those that provide some benefit to another individual. Allonursing, the nursing of non-descendent young, is often considered a cooperative behaviour and is assumed to provide benefits to recipient offspring in terms of growth and survival, and to their mothers, by enabling them to share the lactation load. However, these proposed benefits are not well understood, in part because maternal and litter traits and other ecological and social variables are not independent of one another, making patterns hard to discern using standard univariate analyses. Here, we investigate the potential benefits of allonursing in the cooperatively breeding Kalahari meerkat, where socially subordinate females allonurse the young of a dominant pair without having young of their own. We use structural equation modelling to allow us to account for the interdependence of maternal traits, litter traits and environmental factors. We find no evidence that allonursing provides benefits to pups or mothers. Pups that received allonursing were not heavier at emergence and did not have a higher survival rate than pups that did not receive allonursing. Mothers whose litters were allonursed were not in better physical condition, did not reconceive faster and did not reduce their own nursing investment compared to mothers who nursed their litters alone. These patterns were not significantly influenced by whether mothers were in relatively good, or poor, condition. We suggest that allonursing may persist in this species because the costs to allonurses may be low. Alternatively, allonursing may confer other, more cryptic, benefits to pups or allonurses, such as immunological or social benefits.KJM was supported by a research grant from the Cambridge Philosophical Society. KEM was supported by a US National Science Foundation grant to Alison Bell and KEM (NSF IOS 1121980).This is the accepted manuscript. The final version is available at http://onlinelibrary.wiley.com/doi/10.1111/1365-2656.12343/abstract

Development of Semi-Span Model Test Techniques

A computational investigation was performed to support the development of a semispan model test capability in the NASA Langley Research Center's National Transonic Facility. This capability is desirable for the testing of advanced subsonic transport aircraft at full-scale Reynolds numbers. A state-of-the-art three-dimensional Navier-Stokes solver was used to examine methods to improve the flow over a semi-span configuration. First, a parametric study is conducted to examine the influence of the stand-off height on the flow over the semispan model. It is found that decreasing the stand-off height, below the maximum fuselage radius, improves the aerodynamic characteristics of the semi-span model. Next, active sidewall boundary layer control techniques are examined. Juncture region blowing jets, upstream tangential blowing, and sidewall suction are found to improve the flow over the aft portion of the semispan model. Both upstream blowing and suction are found to reduce the sidewall boundary layer separation. The resulting near surface streamline patterns are improved, and found to be quite similar to the full-span results. Both techniques however adversely affect the pitching moment coefficient

Electrical Scanning Probe Microscope Measurements Reveal Surprisingly High Dark Conductivity in Y6 and PM6:Y6 and Non-Langevin Recombination in PM6:Y6

We used broadband local dielectric spectroscopy (BLDS), an electric force microscopy technique, to make non-contact measurements of conductivity in the dark and under illumination of PM6:Y6 and Y6 prepared on ITO and PEDOT:PSS/ITO. Over a range of illumination intensities, BLDS spectra were acquired and fit to an impedance model of the tip-sample interaction to obtain a sample resistance and capacitance. By comparing two descriptions of cantilever friction, an impedance model and a microscopic model, we connected the sample resistance inferred from impedance modeling to a microscopic sample conductivity. A charge recombination rate was estimated from plots of the conductivity versus light intensity and found to be sub-Langevin. The dark conductivity was orders of magnitude higher than expected from Fermi-level equilibration of the PM6:Y6 with the substrate, suggesting that dark carriers may be a source of open-circuit voltage loss in PM6:Y6

Slow relaxation in granular compaction

Experimental studies show that the density of a vibrated granular material evolves from a low density initial state into a higher density final steady state. The relaxation towards the final density value follows an inverse logarithmic law. We propose a simple stochastic adsorption-desorption process which captures the essential mechanism underlying this remarkably slow relaxation. As the system approaches its final state, a growing number of beads have to be rearranged to enable a local density increase. In one dimension, this number grows as $N=\rho/(1-\rho)$, and the density increase rate is drastically reduced by a factor $e^{-N}$. Consequently, a logarithmically slow approach to the final state is found $\rho_{\infty}-\rho(t)\cong 1/\ln t$.Comment: revtex, 4 pages, 3 figures, also available from http://arnold.uchicago.edu/~ebn

A systematic review of biomarkers for disease progression in Parkinson's disease

This article presents independent research funded by the National Institute for Health Research (NIHR) under its Programme Grants for Applied Research Programme (Grant Reference Number RP-PG-0707-10124).BACKGROUND: Using surrogate biomarkers for disease progression as endpoints in neuroprotective clinical trials may help differentiate symptomatic effects of potential neuroprotective agents from true disease-modifying effects. A systematic review was undertaken to determine what biomarkers for disease progression in Parkinson's disease (PD) exist. METHODS: MEDLINE and EMBASE (1950-2010) were searched using five search strategies. Abstracts were assessed to identify papers meriting review in full. Studies of participants with idiopathic PD diagnosed by formal criteria or clearly described clinical means were included. We made no restriction on age, disease duration, drug treatment, or study design. We included studies which attempted to draw associations between any tests used to investigate disease progression and any clinical measures of disease progression. The electronic search was validated by hand-searching the two journals from which most included articles came. RESULTS: 183 studies were included: 163 (89%) cross-sectional, 20 (11%) longitudinal. The electronic search strategy had a sensitivity of 71.4% (95% CI 51.1-86.0) and a specificity of 97.1% (95% CI 96.5-97.7). In longitudinal studies median follow-up was 2.0 years (IQR 1.1-3.5). Included studies were generally poor quality--cross-sectional with small numbers of participants, applying excessive inclusion/exclusion criteria, with flawed methodologies and simplistic statistical analyses. CONCLUSION: We found insufficient evidence to recommend the use of any biomarker for disease progression in PD clinical trials, which may simply reflect the poor quality of research in this area. We therefore present a provisional 'roadmap' for conducting future disease progression biomarker studies, and recommend new quality criteria by which future studies may be judged.Publisher PDFPeer reviewe