Palatini's cousin: A New Variational Principle

A variational principle is suggested within Riemannnian geometry, in which an auxiliary metric and the Levi Civita connection are varied independently. The auxiliary metric plays the role of a Lagrange multiplier and introduces non-minimal coupling of matter to the curvature scalar. The field equations are 2nd order PDEs and easier to handle than those following from the so-called Palatini method. Moreover, in contrast to the latter method. no gradients of the matter variables appear. In cosmological modeling, the physics resulting from the new variational principle will differ from the modeling using the Palatini method.Comment: 12 page

Mission Accomplished: A Reply to Reuveny and Keshk

Reuveny and Keshk (“Reconsidering trade and conflict simultaneity: The risk of emphasizing technique over substance,” this issue, 2013) argue that the econometric techniques used by Goenner (Conflict Management and Peace Science 28(5): 459–477, 2011) to test and control for endogeneity when estimating the relationship between trade and conflict lack substance. Both sets of authors propose the use of instrumental variable methods, which are known by econometricians to be the natural remedy for estimation with potentially endogenous regressors. Where Goenner (2011) and Reuveny and Keshk (2013) agree is that theory should guide variable selection and the model’s specification. Yet they differ in that, while econometric tests cannot replace theory, one should not trust the appropriateness of the model’s specification based on theory alone – one should also verify. Otherwise, as Goenner (2011) notes, attempts to control for endogeneity may fail

Economic War and Democratic Peace

Research has shown that democracies rarely, if ever, engage each other in war and are less likely to have militarized disputes than when interacting with authoritarian regimes. Economic sanctions are an alternative to militarized conflict viewed by the masses as more acceptable. The conflict-inhibiting effects of democratic norms and institutions are thus weakened with respect to the use of sanctions. This paper examines whether a country\u27s decision to initiate sanctions is influenced by its regime type as well as that of the potential target. The results for the period 1950 to 1990 indicate that the more democratic a country is, the more likely it is to initiate sanctions. Democracies, however, are less likely to target other democratic regimes relative to nondemocratic regimes. With respect to sanctions use, pairs of democracies are not peaceful

Simultaneity between Trade and Conflict: Endogenous Instruments of Mass Destruction

The classical liberal belief is trade, which economically benefits countries, creates ties binding the interests of countries and reduces conflict. While the vast majority of the empirical literature supports this view, recent research questions these findings by also considering the reciprocal relationship between trade and conflict. If conflict also influences trade, then trade is an endogenous right hand side regressor and previous estimates which ignore this are inconsistent. This article determines when one uses appropriate instruments for the endogenous regressors that trade reduces conflict and conflict reduces trade. Failure to use such instruments results in inconsistent estimates and can lead to the spurious conclusion that trade increases conflict. The lesson is the use of inappropriate instruments can be worse than not using them at all

Incorporating Writing Into An Introductory Business And Economics Statistics Course: A Practical Approach

Writing across the curriculum (WAC) has become a guiding principle at many institutions of higher education.  Unfortunately for many students of economics and business the standard vehicles of WAC do not adequately prepare them for the type of writing appropriate for the audience they are expected to address upon graduation.  We describe a method of implementing writing into the introductory statistics courses that are required by many programs in economics and business.  This method addresses the shortcomings of the standard vehicles of WAC while at the same time providing instructors with a feasible solution to do so in light of the multiple constraints faced by many instructors of this type of course.  (JEL A22

A class of anisotropic (Finsler-) space-time geometries

A particular Finsler-metric proposed in [1,2] and describing a geometry with a preferred null direction is characterized here as belonging to a subclass contained in a larger class of Finsler-metrics with one or more preferred directions (null, space- or timelike). The metrics are classified according to their group of isometries. These turn out to be isomorphic to subgroups of the Poincar\'e (Lorentz-) group complemented by the generator of a dilatation. The arising Finsler geometries may be used for the construction of relativistic theories testing the isotropy of space. It is shown that the Finsler space with the only preferred null direction is the anisotropic space closest to isotropic Minkowski-space of the full class discussed.Comment: 12 pages, latex, no figure

Local free-fall temperature of a RN-AdS black hole

We use the global embedding Minkowski space (GEMS) geometries of a (3+1)-dimensional curved Reissner-Nordstr\"om(RN)-AdS black hole spacetime into a (5+2)-dimensional flat spacetime to define a proper local temperature, which remains finite at the event horizon, for freely falling observers outside a static black hole. Our extended results include the known limiting cases of the RN, Schwarzschild--AdS, and Schwarzschild black holes.Comment: 18 pages, 11 figures, version to appear in Int. J. Mod. Phys.