944 research outputs found
Measuring constituency ideology in U.S. house districts: A top-down simulation approach
One of the most intractable problems associated with studying representation in the U.S. House of Representatives involves the measurement of district-level constituency opinion. In measuring constituency opinion in House districts, scholars have relied on a number of alternative approaches, including the use of demographic variables, small-sample estimates of public opinion, presidential election results, referenda data, and "bottom-up" simulated opinion. In this article we develop an innovative "top-down" simulation of House district opinion that provides more reliable and valid measures of House district ideology. We model state-level ideology (as measured by Erikson, Wright, and McIver 1993) as a function of various demographic and political variables found at both the state and House district levels, and then use the estimates from the state-level model to generate predicted ideology scores for each House district during the 1980s and 1990s. Our findings suggest that the top-down simulated measure is a valid indicator of House district ideology that can be used in a number of research venues. Representation is particularly important to democratic theory. According to Considering the important role that representation plays in democracies, the study of representation has occupied a central place in the field of political science and has long captivated the interest of both theorists and empirical analysts. Although scholars have explored a range of representational behaviors, the focus of much of this research has been on what The concept of policy representation requires at least some level of congruence between the policy views of constituents and the policy behavior of repre
Ground State Electromagnetic Moments of <sup>37</sup>Ca
The hyperfine coupling constants of neutron deficient Ca were deduced from the atomic hyperfine spectrum of the transition in Ca II, measured using the collinear laser spectroscopy technique. The ground-state magnetic-dipole and spectroscopic electric-quadrupole moments were determined for the first time as and fm, respectively. The experimental values agree well with nuclear shell model calculations using the universal sd model-space Hamiltonians versions A and B (USDA/B) in the -model space with a 95\% probability of the canonical nucleon configuration. It is shown that the magnetic moment of Ca requires a larger non--shell component than that of Ca for good agreement with the shell-model calculation, indicating a more robust closed sub-shell structure of Ca at the neutron number = 16 than Ca. The results are also compared to valence-space in-medium similarity renormalization group calculations based on chiral two- and three-nucleon interactions
Isolation of Flow and Nonflow Correlations by Two- and Four-Particle Cumulant Measurements of Azimuthal Harmonics in 200 GeV Au+Au Collisions
A data-driven method was applied to measurements of Au+Au collisions at
200 GeV made with the STAR detector at RHIC to isolate
pseudorapidity distance -dependent and -independent
correlations by using two- and four-particle azimuthal cumulant measurements.
We identified a component of the correlation that is -independent,
which is likely dominated by anisotropic flow and flow fluctuations. It was
also found to be independent of within the measured range of
pseudorapidity . The relative flow fluctuation was found to be for particles of transverse momentum
less than GeV/. The -dependent part may be attributed to
nonflow correlations, and is found to be relative to the
flow of the measured second harmonic cumulant at
Charged-to-neutral correlation at forward rapidity in Au+Au collisions at =200 GeV
Event-by-event fluctuations of the ratio of inclusive charged to photon
multiplicities at forward rapidity in Au+Au collision at =200
GeV have been studied. Dominant contribution to such fluctuations is expected
to come from correlated production of charged and neutral pions. We search for
evidences of dynamical fluctuations of different physical origins. Observables
constructed out of moments of multiplicities are used as measures of
fluctuations. Mixed events and model calculations are used as baselines.
Results are compared to the dynamical net-charge fluctuations measured in the
same acceptance. A non-zero statistically significant signal of dynamical
fluctuations is observed in excess to the model prediction when charged
particles and photons are measured in the same acceptance. We find that, unlike
dynamical net-charge fluctuation, charge-neutral fluctuation is not dominated
by correlation due to particle decay. Results are compared to the expectations
based on the generic production mechanism of pions due to isospin symmetry, for
which no significant (<1%) deviation is observed.Comment: 14 pages, 6 figure
Beam energy dependent two-pion interferometry and the freeze-out eccentricity of pions in heavy ion collisions at STAR
We present results of analyses of two-pion interferometry in Au+Au collisions
at = 7.7, 11.5, 19.6, 27, 39, 62.4 and 200 GeV measured in the
STAR detector as part of the RHIC Beam Energy Scan program. The extracted
correlation lengths (HBT radii) are studied as a function of beam energy,
azimuthal angle relative to the reaction plane, centrality, and transverse mass
() of the particles. The azimuthal analysis allows extraction of the
eccentricity of the entire fireball at kinetic freeze-out. The energy
dependence of this observable is expected to be sensitive to changes in the
equation of state. A new global fit method is studied as an alternate method to
directly measure the parameters in the azimuthal analysis. The eccentricity
shows a monotonic decrease with beam energy that is qualitatively consistent
with the trend from all model predictions and quantitatively consistent with a
hadronic transport model.Comment: 27 pages; 27 figure
The closely related rare and severe acute myeloid leukemias carrying EVI1 or PRDM16 rearrangements share singular biological features
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