Arbitrage opportunities and immunization

It is often argued that an immunization strategy violates arbitrage-free equilibrium. Because immunization is a static concept, we contend that this argument is not valid. This paper examines the immunization strategy in a dynamic setting, and shows that global immunization is feasible for any arbitrage-free affine term structure model, including the parallel shift model. Further, we show that immunization does not violate arbitrage-free pricing because the cost of immunization over time is positive. Consequently, immunization strategies based upon commonly used duration, measures are not theoretically unsound.     

Top dominance and the possibility of strategy-proof stable solutions to matching problems

Summary This paper explores the possibility of designing strategy-proof mechanisms yielding satisfactory solutions to the marriage and to the college admissions problem. Our first result is negative. We prove that no strategy-proof mechanism can always choose marriages that are individually rational and Pareto efficient. This strengthens a result by Roth (1982) showing that strategy-proof mechanisms cannot always select stable marriages. The result also applies, a fortiori, to college admissions. Since finding difficulties with strategy-proofness is quite an expected result, we then address a second question which is classical within the incentives literature. Are there restrictions on the preferences of agents under which strategy-proof and stable mechanisms do exist? We identify a nontrivial restriction on the domain of preferences, to be called top dominance, under which there exist strategy-proof and stable mechanisms for both types of matching problems. The mechanisms turn out to be exactly those that derive from the most classical algorithms in the literature; namely, the women's optimal, the men's optimal and the student's optimal. Finally, top dominance is shown to be essentially necessary, as well as sufficient, for the existence of strategy-proof stable matching mechanisms.This work is partially supported by grant PB 89-0294, from the Directión General de Investigatión Ciencia y Tecnología of the Spanish Ministerio de Educación y Ciencia. Salvador Barberà is also grateful to the Instituto de Estudios Fiscales. This research was initiated while both authors were visting GREMAQ, Université des Sciencies Sociales, Toulouse, whose hospitality is gratefully acknowledged. The paper extends results that were circulated as GREMAQ W.P. 91.22.232. We are grateful to Matthew Jackson and Marilda Sotomayor for their comments.     

International, Local and Regional Government Alliances

Kent County Council now promotes itself as the 'European County', a message that it seeks to deliver to the heart of institutional Europe through its Brussels office. Commentators generally agree that Kent has demonstrated how British local authorities can play an influential role at the European level, but will this acknowledged success be sufficient to maintain Kent's position over the coming years in a rapidly changing Europe where large regions look set to wield the power? This article reviews how Kent formed alliances with authorities in the same region of north-west Europe. How real are these supra-national groupings and what benefits can they bring to the partner areas?     

Healthcare burden and reimbursement of hospitalization during chemotherapy for adults with Ph-negative relapsed or refractory B-cell precursor acute lymphoblastic leukemia in France: a retrospective chart review

Objective: Philadelphia chromosome negative [Ph(?)] relapsed or refractory (R/R) B-precursor acute lymphoblastic leukemia (ALL) is an extremely rare condition requiring intensive treatment. This retrospective chart review aimed to quantify hospitalizations and reimbursement in this patient population in France.

Methods: Patients aged ≥18 years and with at least one hospitalization for Ph(?) R/R B-precursor ALL were included in the study. They were relapsed with first remission lasting <12 months, relapsed after first salvage therapy, relapsed any time after hematopoietic stem cell transplant (HSCT), or were refractory to initial or salvage therapy. Data were collected from the index date (first diagnosis of R/R ALL) until death or loss to follow-up. The chemotherapy period was defined as the first chemotherapy date after the index date to the earliest of death, loss to follow-up, last chemotherapy dose plus 30 days, or initiation of HSCT. The primary outcome was the percentage of time hospitalized during the chemotherapy period.

Results: Thirty-three patients were included, with a mean age of 49 years. The mean proportion of time spent in the hospital during the chemotherapy period was 46% (95% CI =34–57%). Patients had a mean of 2.2 (SD =1.5) inpatient hospitalizations and the mean length of stay per hospitalization was 16.8 (SD =14.8) days. During the chemotherapy period, the mean amount reimbursed per hospitalization was €31 067 (SD = €4850) and the total hospitalization reimbursement per patient was €68 344. From the index date to death, excluding HSCT, the total reimbursement per patient was €108 873.

Limitations: The sample size was small, although this was expected given the rarity of the patient population.

Conclusions: Adults with Ph(?) R/R B-precursor ALL had repeated and prolonged hospitalizations during salvage chemotherapy. Approximately half the follow-up period was spent in the hospital, and this time was associated with high economic burden in France.     

Noise trading and prime and score premiums

This paper documents that a common element drives the time-series variation of the premium pricing of Primes and Scores. I argue that this common element is noise trading. The noise trading model of Delong, Shleifer, Summers and Waldmann (1990) predicts that returns on assets that are predominantly traded by noise traders will be correlated, since the misperceptions of noise traders are cross-sectionally correlated. Consistent with the noise trading hypothesis, changes in the average premium of Primes and Scores, which are predominantly traded by individual investors, are correlated with both changes in average discounts of closed-end funds and small firms returns. These empirical facts provide additional evidence that noise traders can affect security prices.     

Bond immunization for additive interest rate shocks

This paper explores bond immunization for additive term structure models. This class of term structures contains many models that are commonly used in the duration and immunization literature. We establish the necessary and sufficient conditions for immunization and prove the existence of a bond portfolio that satisfies the immunization condition. Based upon the immunization condition, we develop a general definition of duration that applies to any additives term structure model.     

An assessment of railway capacity

In this paper, we review the main concepts and methods to perform capacity analyses, and we present an automated tool that is able to perform several capacity analyses. Capacity is extremely dependent on infrastructure, traffic, and operating parameters. Therefore, an in-depth study of the main factors that influence railway capacity is performed on several Spanish railway infrastructures. The results show how the capacity varies according to factors such as train speed, commercial stops, train heterogeneity, distance between railway signals, and timetable robustness.