Flip-Flopping: Ideological Adjustment Costs in the United States Senate

Models of electoral competition in which candidates can change position at no cost predict the convergence of platforms in a two-candidate election. Such convergence is at odds with empirical observation. In this paper, I undertake a study of candidate positioning in the United States Senate and determine the extent to which electoral costs associated with changing position explain the ideological positions taken by Senators. Using over 50 years of roll call voting data, I use a simulated method of moments approach to estimate a dynamic model of candidate positioning for U.S. Senators. The findings support a model in which Senators face convex costs to changing position, with the best fitting model being one with linear costs of adjustment. The model thus predicts severe punishments for “flip-flopping” Senators (those who make large changes in position). As a result of the significant costs associated with adjusting position, the empirical validity of the Median Voter Theorem (which depends upon candidates being able to change position at no cost) is called into question.spatial models, dynamic political economy, Senate, ideology

PRE-DEVONIAN, BRABANTIAN DEFORMATION WITHIN THE SOUTHERN CONDROZ INLIER (RUISSEAU DES CHEVREUILS, DAVE, BELGIUM)

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Influence of slump folds on tectonic folds: an example from the Lower Ordovician of the Anglo-Brabant Deformation Belt (Belgium)

Although it is generally accepted that buckle folds will not develop in a perfectly planar layer without the presence of some irregularity or perturbation at which the folds initiate, there are very few cases in which individual natural folds can be linked to specific irregularities. Within the Lower Ordovician Abbaye de Villers Formation, Anglo-Brabant Deformation Belt, metre-scale tectonic folds occur, of which the position and, to a certain extent, the geometry appear to be controlled by slump folds and related features. The metre-scale tectonic folds, interpreted as parasitic structures on the limb of a large-scale host fold, occur only within a stratigraphic level affected by slumping. In this level, tectonic antiforms tend to form superimposed on antiformal slump folds and on zones of abrupt, slump-related thickness increase, and tectonic synforms on synformal slump folds and on zones of abrupt thickness decrease. The rather irregular 3D geometry of sedimentary sequences suggests that many more similar cases should exist in which folds can be linked to specific irregularities. However, possibly it is also this abundance of irregularities in sedimentary sequences, in combination with fold and outcrop scale, that makes it difficult to attribute a particular fold to a particular perturbation

Stability of character sums for positive-depth, supercuspidal representations

We re-write the character formul{\ae} of Adler and the second-named author in a form amenable to explicit computations in $p$-adic harmonic analysis, and use them to prove the stability of character sums for a modification of Reeder's conjectural positive-depth, unramified, toral supercuspidal L-packets