Pour un joueur canadien de hockey mineur, il existe un rapport étroit entre son mois de naissance et les chances qu'il aura de jouer dans une équipe de très haut niveau. Les joueurs nés dans les premiers mois de l'année sont avantagés. On attribue généralement ce fait au système de classification, dans le hockey mineur, qui groupe les joueurs en catégories selon l'âge. Dans cet article, nous commençons par un examen de la situation actuelle. Ensuite, nous montrons que le système de classification basé sur l'âge ne constitue pas une explication suffisante; il faut aussi compter avec une répartition qui s'opère très tôt (c-à-d. la division des joueurs en équipes représentatives et en équipes de ligue-maison.) Nous suggérons un système de classification plus équitable et, finalement, nous examinons les implications de politiques d'intérêt public.There is strong relationship between birthmonth and the chance that a Canadian minor hockey player will play at an elite level. Players born in the early months of the year have an advantage. This is generally attributed to the slotting system: the way in which minor hockey groups players into age divisions. In this paper we first review the evidence. We then argue that there is more to the explanation of this relative age effect than just the slotting system; it also depends on early streaming (i.e., the partitioning of players into representative and house league teams). We suggest a more equitable slotting system, and finally, we discuss public policy implications.

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We de"ne a wash criterion as one where the decision-maker is indi!erent among the alternatives when they are compared on that criterion. In view of the Belton}Gear example and other such anomalies associated with the analytic hierarchy process (AHP), we ask whether eliminating a wash criterion will a!ect the overall ranking of objects. In the case where there is only one level of criteria, the rank-order of objects is una!ected by leaving out a wash criterion. However, in the case where the wash criterion is a subcriterion, the rank order may be a!ected by leaving it out. Scope and purposeA wash criterion is de"ned as a criterion where the decision-maker is indi!erent among the alternatives when they are compared on that criterion. We would like to think that the overall rank-order of objects would be una!ected in the case where the wash criterion is excluded. We give an example of an AHP hierarchy where this is not the case. In our view this presents another challenge to the AHP methodology.

Relativistic wave equations a r e derived which generalize the recently obtained Galileic o~a r i a n t wave equations for massive particles with any integer or half-integer spin. Imposing a minimality condition on the number of components possessed by the relativistic wave function, it i s shown that the index transformation properties of the wave function may be either those of the (s, 0)% (S -8 , 4 ) representation of SL(2, C) o r of the representation (0, s),b($, s -6 ) . The minimal extension of these representations which accommodates reflection symmetry yields the Dirac equation for s = $, the Duffin-Kemmer equation for s = 1, and an equation for particles with s > 1 whose wave-function indices transform according to the (s, 0 ) 7 ( s -4, $ ),i3(;, s -a )-4(0, s ) representation of SL(2,C). The latter theory possesses 4(2s + 1) independent components, has no subsidiary conditions, and describes a unique mass, m*O, and a unique spin. The theory admits a simple Lagrangian and Hamiltonian formulation and yields a conserved current. Finally, it i s shown that for any spin the equation remains consistent and causal in the presence of a minimally coupled external-electromagnetic-field interaction.

The magnetic moment of a particle of nonzero spin 5 is computed by the introduction of minimal coupling into the appropriate Galilean-invariant wave equation. It is shown that the requirement that the differential equations be of first order, together with a minimality assumption on the number of components, uniquely implies ag factor of l/S. The role played by this minimality condition is made explicit by means of a counterexample .

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sible that as lithium is being removed from the structure the anti-site defect concentration is increased, blocking the lithium diffusion paths and making subsequent lithium intercalation/deintercalation more difficult or even impossible.40,41 This may also be a source of irreversibility in the electrochemical reactions. under contract DE-AC02-76CH0001 to D. E. Cox.