Combined ion and atom trap for low temperature ion-atom physics

We report an experimental apparatus and technique which simultaneously traps ions and cold atoms with spatial overlap. Such an apparatus is motivated by the study of ion-atom processes at temperatures ranging from hot to ultra-cold. This area is a largely unexplored domain of physics with cold trapped atoms. In this article we discuss the general design considerations for combining these two traps and present our experimental setup. The ion trap and atom traps are characterized independently of each other. The simultaneous operation of both is then described and experimental signatures of the effect of the ions and cold-atoms on each other are presented. In conclusion the use of such an instrument for several problems in physics and chemistry is briefly discussed.Comment: 24 pages, 13 figures. Figures Fixe

Party Polarization and the Business Cycle in the United States

A large literature has studied the trend of greaterpolarization between Democrats and Republicans in Congress.This paper empirically examines the extent to which inflationand unemployment explain cyclical movements ofpolarization over time. An informal application of thestandard Downsian spatial competition model of partiesgenerates the following relationships, ceteris paribus: (1)inflation should be associated with policy convergence, (2)unemployment should be associated with polarization, (3) theeffect of unemployment on polarization should be larger inmagnitude than the effect of inflation on convergence, and (4)the effect of unemployment on polarization should be strongerin the House than in the Senate. We estimate the relationshipbetween vote records and business cycle conditions over the1947–1999 period using a GLS model with varying lags. Ourresults are broadly consistent with these business cyclehypotheses of polarization, though greater support is found inHouse data than in Senate data. Copyright Kluwer Academic Publishers 2004

Collusion, Collective Action and Protection: Theory and Evidence

This paper provides a novel explanation forthe formation of protectionist lobby groupsin imperfectly competitive sectors. Thelevel of collusion is shown to be a crucialdeterminant of the ability of firms tosustain lobbying. We show that greatercollusion reduces firm contributionsto tariff lobbying, when the governmentvalues welfare sufficiently and thecross-price elasticity between the domesticand foreign goods is sufficiently high. The empirical evidence from the U.S.supports the theory. Greater collusionreduces the level of PAC contributions. Copyright Kluwer Academic Publishers 2004

Now that we've found love what are we gonna do with it?: a narrative understanding of black identity

This paper offers an interpretation of the changes in Black identity during the last century. By drawing on psychological literature and cultural artefacts, changing understandings of Blackness are read as different narrative forms. The shift from ‘Negro’ to ‘Black’ is presented as a shift from tragicto romanticnarrative, while the ‘African’ narrative that now occupies the centre stage of Black identity represents a satiricalstory. It is suggested that with a growing awareness of being both Black and ‘something else’, the apparent opposing themes in performing Blackness can be resolved by enacting a comedynarrative. There is some evidence that the comedy narrative is present but it has yet to gain ascendancy