An improved AFS phase for AdS3 string integrability

We propose a number of modifications to the classical term in the dressing phase for integrable strings in AdS3 x S3 x S3 x S1, and check these against existing perturbative calculations, crossing symmetry, and the semiclassical limit of the Bethe equations. The principal change is that the phase for different masses should start with a term Q_1 Q_2, like the one-loop AdS3 dressing phase, rather than Q_2 Q_3 as for the original AdS5 AFS phase.Comment: 7 page

Massless L\"uscher Terms and the Limitations of the AdS3 Asymptotic Bethe Ansatz

In AdS5/CFT4 integrability the Bethe ansatz gives the spectrum of long strings, accurate up to exponentially small corrections. This is no longer true in AdS3, as we demonstrate here by studying Luscher F-terms with a massless particle running in the loop. We apply this to the classic test of Hernandez & Lopez, in which the su(2) sector Bethe equations (including one-loop dressing phase) should match the semiclassical string theory result for a circular spinning string. These calculations did not agree in AdS3xS3xT4, and we show that the sum of all massless Luscher F-terms can reproduce the difference.Comment: 15 pages, 1 figure; v2:references, typos and clarification

Quantum Strings and the AdS4/CFT3 Interpolating Function

The existence of a nontrivial interpolating function h(\lambda) is one of the novel features of the new AdS4/CFT3 correspondence involving ABJM theory. At strong coupling, most of the investigation of semiclassical effects so far has been for strings in the AdS4 sector. Several cutoff prescriptions have been proposed, leading to different predictions for the constant term in the expansion h(\lambda)=\sqrt{\lambda/2} + c + ... . We calculate quantum corrections for giant magnons, using the algebraic curve, and show by comparing to the dispersion relation that the same prescriptions lead to the same values of c in this CP3 sector. We then turn to finite-J effects, where a comparison with the Luescher F-term correction shows a mismatch for one of the three sum prescriptions. We also compute some dyonic and higher F-terms for future comparisons.Comment: 30 pages, 1 figure, 1 table. v2 has minor improvements to the text, and extra references. v3 has further textual changes, version to appear in JHE

Immigrant Earnings Distributions and Earnings Mobility in Canada: Evidence for the 1982 Landing Cohort from IMDB Micro Data

This paper provides preliminary results from the IMDB panel database on the earnings distribution and earnings mobility of Canadian immigrants over their first post-landing decade in Canada. In this study we examine only the 1982 landing cohort of immigrants and follow them through to 1992. We examine earnings outcomes by four immigrant admission categories (independent economic immigrants, family class immigrants, and refugees) and separately for men and women. We find that there was indeed a substantial increase in the real earnings of 1982 immigrants over their first ten post-landing years in Canada. Annual earnings were initially highest for independent economic immigrants (all of whom are principal applicants) and lowest for refugees. But the growth rate of earnings was highest among refugees, so that by the tenth post-landing year refugees had the second-highest annual earnings levels after independent economic immigrants. Earnings inequality among immigrants in the 1982 landing cohort changed over the ensuing decade in a manner consistent with onward migration beyond Canada from the top end of the immigrant earnings distribution. In fact, sample attrition in the IMDB database was greatest among independent economic immigrants, followed by refugees. Earnings mobility was substantially greater for immigrants than for earners as a whole in the Canadian labour market, and declined with years since landing for both male and female immigrants. Earnings mobility was also greater among immigrant women than among immigrant men. The results indicate that the point system is effective in admitting higher-earning immigrants who succeed in moving ahead in the Canadian labour market, but suggest that onward (or through) migration among the most skilled immigrant workers may be a policy concern.Immigrant Earnings, Earnings Mobility of Immigrants, Canadian Immigrant Earnings

Immigrant Earnings Differences Across Admission Categories and Landing Cohorts in Canada

This study uses longitudinal IMDB micro data to document the annual earnings outcomes of Canadian immigrants in four major admission categories (skill-assessed independent economic principal applicants, accompanying economic immigrants, family class immigrants, and refugees) and three annual landing cohorts (those for the years 1982, 1988, and 1994) over the first ten years following their landing in Canada as permanent residents. The findings provide a ten-year earnings signature for the four broad immigrant admission categories in Canada. The study’s first major finding is that skill-assessed economic immigrants had consistently and substantially the highest annual earnings levels among the four admission categories for both male and female immigrants in all three landing cohorts. Family class immigrants or refugees generally had the lowest earnings levels. An important related finding is that refugees exhibited substantially the highest earnings growth rates for both male and female immigrants in all three landing cohorts, while independent economic or family class immigrants generally had the lowest earnings growth rates over their first post-landing decade in Canada. The study’s second major finding is that economic recessions appear to have had clearly discernible negative effects on immigrants’ earnings levels and growth rates; moreover, these adverse effects were much more pronounced for male immigrants than for female immigrants.Immigrant earnings, admission categories, Canadian immigrants

Market Power and Structural Adjustment: The Case of West African Cocoa Market Liberalization

Liberalization of the cocoa market in West Africa, due to structural adjustment reforms, has resulted in the elimination of para-statal marketing boards and initiated the creation of new institutions to replace the marketing services of those agencies. Concerns have been raised as to the effects of these reforms on prices of cocoa received by farmers, welfare measures and competitiveness of marketing channels. Of particular importance is backward integration of multinational processing firms, who take over exporting activities and may collect rents previously captured as export taxes. This paper uses a conjectural variations approach to estimate the degree of market power present in the post-liberalized cocoa bean markets of Ivory Coast and Nigeria. Evidence of market power is found in the Ivory Coast markets between the farmgate and U.S./EU15 imports. The market power, exercised by multinational exporter/processors, must be considered in concert with the Ivorian government who is still collecting export taxes. In contrast, no evidence of market power is found in the Nigerian markets or domestic (farmer to trader) markets of Ivory Coast.Marketing,