1,631 research outputs found
What's Good for the Goose is Bad for the Gander: Negative Political Advertising, Partisanship, and Turnout
types: ArticleThis study examines citizens’ perceptions of fairness and legitimacy in political advertising. Using focus groups, an original national survey, and data on election 2000, as well as drawing on results from a replication of the national survey in 2004, we characterize political ads from the citizen's perspective. We then turn to the impact of “negative” advertising on voter turnout. Like several studies, we find circumstances under which turnout can be increased by negative ad criticisms. However, we show that this general result is only part of the story. Drawing on research in political psychology, we suggest that voters are “motivated processors” of advertising claims; as such, they evaluate the fairness of an ad according to their partisan predispositions. We show that when partisans perceive the criticisms of their own party's candidate to be fair, they are less likely to say they will vote. As a result, we find that negative advertising not only may affect the total turnout in an election but also has an important and varying impact on the composition of the electorate
Soil total carbon and nitrogen and crop yields after eight years of tillage, crop rotation, and cultural practice
Information on the long-term effect of management practices on soil C and N stocks is lacking. An experiment was conducted from 2004 to 2011 in the northern Great Plains, USA to examine the effects of tillage, crop rotation, and cultural practice on annualized crop residue (stems + leaves) returned to the soil and grain yield, and soil total C (STC) and total N (STN) stocks at the 0–120 cm depth. Tillage practices were no-tillage (NT) and conventional tillage (CT) and crop rotations were continuous spring wheat (Triticum aestivum L.) (CW), spring wheat-pea (Pisum sativum L.) (W-P), spring wheat-barley (Hordeum vulgaris L.) hay-pea (W-B-P), and spring wheat-barley hay-corn (Zea mays L.)-pea (W-B-C-P). Cultural practices were traditional (conventional seed rates and plant spacing, conventional planting date, broadcast N fertilization, and reduced stubble height) and improved (variable seed rates and plant spacing, delayed planting, banded N fertilization, and increased stubble height). Crop residue and grain yield were greater with CW and W-P than W-B-P and grain yield was greater with the traditional than the improved practice. The STC at 10–20 and 90–120 cm was greater with CW or W-P than other crop rotations in CT and greater with CW than W-B-P in NT. The STN at 20–40 cm was greater with W-P than CW and W-B-P in CT. With NT and the improved cultural practice, STN at 0–5, 5–10, 20–40, and 60–90 cm was greater with W-P and W-B-C-P than other crop rotations. The STN at 0–10 cm correlated with annualized crop residue and grain yield (r = 0.94–0.97, P ≤ 0.05). Increased crop residue returned to the soil increased soil C stock with CW and W-P and N stock with W-P, but removal of aboveground crop biomass for hay decreased stocks with W-B-P. Increased soil N stock had a beneficial effect on crop grain yield
Orientational order in dipolar fluids consisting of nonspherical hard particles
We investigate fluids of dipolar hard particles by a certain variant of
density-functional theory. The proper treatment of the long range of the
dipolar interactions yields a contribution to the free energy which favors
ferromagnetic order. This corrects previous theoretical analyses. We determine
phase diagrams for dipolar ellipsoids and spherocylinders as a function of the
aspect ratio of the particles and their dipole moment. In the nonpolar limit
the results for the phase boundary between the isotropic and nematic phase
agree well with simulation data. Adding a longitudinal dipole moment favors the
nematic phase. For oblate or slightly elongated particles we find a
ferromagnetic liquid phase, which has also been detected in computer
simulations of fluids consisting of spherical dipolar particles. The detailed
structure of the phase diagram and its evolution upon changing the aspect ratio
are discussed in detail.Comment: 35 pages LaTeX with epsf style, 11 figures in eps format, submitted
to Phys. Rev.
Understanding the limits to ethnic change: lessons from Uganda's “lost counties”
The historically constructed nature of ethnicity has become a widely accepted paradigm in the social sciences. Scholars have especially have focused on the ways modern states have been able to create and change ethnic identities, with perhaps the strongest case studies coming from colonial Africa, where the gap between strong states and weak societies has been most apparent. I suggest, however, that in order to better understand how and when ethnic change occurs it is important to examine case studies where state-directed ethnic change has failed. To rectify this oversight I examine the case of the “lost counties” of Uganda, which were transferred from the Bunyoro kingdom to the Buganda kingdom at the onset of colonial rule. I show that British attempts to assimilate the Banyoro residents in two of the lost counties were an unmitigated failure, while attempts in the other five counties were successful. I claim that the reason for these differing outcomes lies in the status of the two lost counties as part of the historic Bunyoro homeland, whereas the other five counties were both geographically and symbolically peripheral to Bunyoro. The evidence here thus suggests that varying ethnic attachments to territory can lead to differing outcomes in situations of state-directed assimilation and ethnic change
Homogeneous nucleation of colloidal melts under the influence of shearing fields
We study the effect of shear flow on homogeneous crystal nucleation, using
Brownian Dynamics simulations in combination with an umbrella sampling like
technique. The symmetry breaking due to shear results in anisotropic radial
distribution functions. The homogeneous shear rate suppresses crystal
nucleation and leads to an increase of the size of the critical nucleus. These
observations can be described by a simple, phenomenological extension of
classical nucleation theory. In addition, we find that nuclei have a
preferential orientation with respect to the direction of shear. On average the
longest dimension of a nucleus is along the vorticity direction, while the
shortest dimension is preferably perpendicular to that and slightly tilted with
respect to the gradient direction.Comment: 10 pages, 8 figures, Submitted to J. Phys.: Condens. Matte
Healthcare professionals' perceptions of pain in infants at risk for neurological impairment
BACKGROUND: To determine whether healthcare professionals perceive the pain of infants differently due to their understanding of that infant's level of risk for neurological impairment. METHOD: Neonatal Intensive Care Units (NICU's) at two tertiary pediatric centers. Ninety-five healthcare professionals who practice in the NICU (50 nurses, 19 physicians, 17 respiratory therapists, 9 other) participated. They rated the pain (0–10 scale and 0–6 Faces Pain Scale), distress (0–10), effectiveness of cuddling to relieve pain (0–10) and time to calm without intervention (seconds) for nine video clips of neonates receiving a heel stick. Prior to each rating, they were provided with descriptions that suggested the infant had mild, moderate or severe risk for neurological impairment. Ratings were examined as a function of the level of risk described. RESULTS: Professionals' ratings of pain, distress, and time to calm did not vary significantly with level of risk, but ratings of the effectiveness of cuddling were significantly lower as risk increased [F (2,93) = 4.4, p = .02]. No differences in ratings were found due to participants' age, gender or site of study. Physicians' ratings were significantly lower than nurses' across ratings. CONCLUSION: Professionals provided with visual information regarding an infants' pain during a procedure did not display the belief that infants' level of risk for neurological impairment affected their pain experience. Professionals' estimates of the effectiveness of a nonpharmacological intervention did differ due to level of risk
Cluster Analysis of Obesity and Asthma Phenotypes
Asthma is a heterogeneous disease with variability among patients in characteristics such as lung function, symptoms and control, body weight, markers of inflammation, and responsiveness to glucocorticoids (GC). Cluster analysis of well-characterized cohorts can advance understanding of disease subgroups in asthma and point to unsuspected disease mechanisms. We utilized an hypothesis-free cluster analytical approach to define the contribution of obesity and related variables to asthma phenotype.In a cohort of clinical trial participants (n = 250), minimum-variance hierarchical clustering was used to identify clinical and inflammatory biomarkers important in determining disease cluster membership in mild and moderate persistent asthmatics. In a subset of participants, GC sensitivity was assessed via expression of GC receptor alpha (GCRα) and induction of MAP kinase phosphatase-1 (MKP-1) expression by dexamethasone. Four asthma clusters were identified, with body mass index (BMI, kg/m(2)) and severity of asthma symptoms (AEQ score) the most significant determinants of cluster membership (F = 57.1, p<0.0001 and F = 44.8, p<0.0001, respectively). Two clusters were composed of predominantly obese individuals; these two obese asthma clusters differed from one another with regard to age of asthma onset, measures of asthma symptoms (AEQ) and control (ACQ), exhaled nitric oxide concentration (F(E)NO) and airway hyperresponsiveness (methacholine PC(20)) but were similar with regard to measures of lung function (FEV(1) (%) and FEV(1)/FVC), airway eosinophilia, IgE, leptin, adiponectin and C-reactive protein (hsCRP). Members of obese clusters demonstrated evidence of reduced expression of GCRα, a finding which was correlated with a reduced induction of MKP-1 expression by dexamethasoneObesity is an important determinant of asthma phenotype in adults. There is heterogeneity in expression of clinical and inflammatory biomarkers of asthma across obese individuals. Reduced expression of the dominant functional isoform of the GCR may mediate GC insensitivity in obese asthmatics
Ultrafast quasiparticle relaxation dynamics in normal metals and heavy fermion materials
We present a detailed theoretical study of the ultrafast quasiparticle
relaxation dynamics observed in normal metals and heavy fermion materials with
femtosecond time-resolved optical pump-probe spectroscopy. For normal metals, a
nonthermal electron distribution gives rise to a temperature (T) independent
electron-phonon relaxation time at low temperatures, in contrast to the
T^{-3}-divergent behavior predicted by the two-temperature model. For heavy
fermion compounds, we find that the blocking of electron-phonon scattering for
heavy electrons within the density-of-states peak near the Fermi energy is
crucial to explain the rapid increase of the electron-phonon relaxation time
below the Kondo temperature. We propose the hypothesis that the slower Fermi
velocity compared to the sound velocity provides a natural blocking mechanism
due to energy and momentum conservation laws.Comment: 10 pages, 11 figure
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