Spatially-resolved potential measurement with ion crystals

We present a method to measure potentials over an extended region using one-dimensional ion crystals in a radio frequency (RF) ion trap. The equilibrium spacings of the ions within the crystal allow the determination of the external forces acting at each point. From this the overall potential, and also potentials due to specific trap features, are calculated. The method can be used to probe potentials near proximal objects in real time, and can be generalized to higher dimensions.Comment: 7 pages (double spaced), 3 figure

Production of Lambda and Sigma^0 hyperons in proton-proton collisions

This paper reports results on simultaneous measurements of the reaction channels pp -> pK+\Lambda and pp -> pK+\Sigma^0 at excess energies of 204, 239, and 284 MeV (\Lambda) and 127, 162, and 207 MeV (\Sigma^0). Total and differential cross sections are given for both reactions. It is concluded from the measured total cross sections that the high energy limit of the cross section ratio is almost reached at an excess energy of only about 200 MeV. From the differential distributions observed in the overall CMS as well as in the Jackson and helicity frames, a significant contribution of interfering nucleon resonances to the \Lambda production mechanism is concluded while resonant \Sigma^0-production seems to be of lesser importance and takes place only through specific partial waves of the entrance channel. The data also indicate that kaon exchange plays a minor role in the case of \Lambda- but an important role for \Sigma^0-production. Thus the peculiar energy dependence of the \Lambda-to-\Sigma^0 cross section ratio appears in a new light as its explanation requires more than mere differences between the p\Lambda and the p\Sigma^0 final state interaction. The data provide a benchmark for theoretical models already available or yet to come.Comment: 18 pages, 10 figures; accepted by The European Physical Journal A (EPJ A

Study of the decay mode D^0 -> K-K+pi-pi+

Using data from the FOCUS (E831) experiment at Fermilab, we present a new measurement of the branching ratio for the Cabibbo-favored decay mode $D^0 \to K^-K^+\pi^-\pi^+$. From a sample of $2669 \pm 101$ fully reconstructed $D^0 \to K^-K^+\pi^-\pi^+$ events, we measure $\Gamma(D^0 \to K^-K^+\pi^-\pi^+)/\Gamma(D^0 \to K^-\pi^-\pi^+\pi^+) = 0.0295 \pm 0.0011(stat.) \pm 0.0008(syst.)$. A coherent amplitude analysis has been performed to determine the resonant substructure of this decay mode. This analysis reveals a dominant contribution from $D^0 \to K_1^+ K-$ modes.Comment: 19 pages, 6 figures, to be submitted to Physics Letters

Migrant Mobilization Between Political Institutions and Citizenship Regimes. A Comparison of France and Switzerland

Thisarticlefocusesonthepoliticalclaimsmadebyimmigrantsandethnicminori- ties in France and Switzerland. We look at cross-national variations in the overall presence of immigrants and ethnic minorities in the national public space, and the forms and content of their claims. Following a political opportunity approach, we argue that claim-making is affected both by institutional opportunities and by national models of citizenship. The civic- assimilationist conception of citizenship in France gives migrants greater legitimacy to intervene in the national public space. Furthermore, the inclusive definition of ‘membership in the national community' favors claims pertaining to minority integration politics. However, the pressure toward assimilation to the republican norms and values tends to provoke claims for the recognition of ethnic and cultural difference. Finally, closed institutional opportunities push migrants' mobilization to become more radical, but at the same time the more inclusive model of citizenship favors a moderate action repertoire of migrants. Conversely, the ethnic-assimilationist view in Switzerland leads migrants to stress homeland-related claims. When they do address the policy field of ethnic relations, immigration and citizen- ship, they focus on issues pertaining to the entry and stay in the host society. Finally, the forms of action are more moderate due to the more open institutional context, but at the same time the action repertoire of migrants is moderated by the more exclusive model of citizenship. Our article is an attempt to specify the concept of ‘political opportunity structure', and to combine institutional and cultural factors in explaining claim-making by immi- grants and ethnic minorities. We confront our arguments with data from a comparative project on the mobilization on ethnic relations, citizenship and immigration

Pregnancy in women with hypertrophic cardiomyopathy: data from the European Society of Cardiology initiated Registry of Pregnancy and Cardiac disease (ROPAC)

Aims We report the maternal and foetal outcomes at birth and after 6 months in a cohort of pregnant women with hypertrophic cardiomyopathy (HCM). Although most women with HCM tolerate pregnancy well, there is an increased risk of obstetric and cardiovascular complications. Methods and results All pregnant women with HCM entered into the prospective worldwide Registry of Pregnancy and Cardiac disease (ROPAC) were included in this analysis. The primary endpoint was a major adverse cardiovascular event (MACE), which included death, heart failure (HF), thrombo-embolic event, and arrhythmia. Baseline and outcome data were analysed and compared for patients with MACE vs. without MACE and for patients with obstructive HCM vs. non-obstructive HCM. Sixty pregnant women (mean age 30.4 +/- 6.0 years) with HCM (41.7% obstructive) were included. No maternal mortality occurred in this cohort. In 14 (23%) patients at least one MACE occurred: 9 (15.0%) HF and 7 (12%) an arrhythmia (6 ventricular and 1 atrial fibrillation). MACE occurred most commonly during the 3rd trimester and postpartum period. In total, 3 (5.0%) women experienced foetal loss. Women with MACE had a higher rate of emergency Caesarean delivery for cardiac reasons (21.4% vs. 0%, P = 0.01). No significant differences in pregnancy outcome were found between women with obstructive and non-obstructive HCM. NYHA functional class of >= II and signs of HF before pregnancy, were associated with MACE. Conclusion Although most women with HCM tolerated pregnancy well, cardiovascular complications were not uncommon and predicted by pre-pregnancy status facilitating pre-pregnancy counselling and targeted antenatal care