Tom Petersen

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STUDY DESIGN A randomized controlled comparative trial with an 8-month follow-up period was conducted. OBJECTIVE To compare the effect of the McKenzie treatment method with that of intensive dynamic strengthening training in patients with subacute or chronic low back pain. SUMMARY OF BACKGROUND DATA Randomized studies indicate that the efficacy of the(More)
Most patients referred to physiotherapy with low back pain are without a precise medical diagnosis. Identification of subgroups of non-specific low back pain patients may improve clinical outcomes and research efficiency. A pathoanatomic classification system has been developed, classifying patients with non-specific low back pain into 12 different(More)
We generalize Stembridge’s enriched P -partitions and use this theory to outline the structure of peak algebras for the symmetric group and the hyperoctahedral group. Whereas Stembridge’s enriched P partitions are related to quasisymmetric functions (the coalgebra dual to Solomon’s type A descent algebra), our generalized enriched P -partitions are related(More)
STUDY DESIGN Randomized controlled trial. OBJECTIVE To compare the effects of the McKenzie method performed by certified therapists with spinal manipulation performed by chiropractors when used adjunctive to information and advice. SUMMARY OF BACKGROUND DATA Recent guidelines recommend a structured exercise program tailored to the individual patient as(More)
STUDY DESIGN A report on plenary presentations and discussions of an expert panel and workshop ("Exercise as a treatment for subacute low back pain") that was held at the Amsterdam Forum VIII on Low Back Pain Research in Primary Care. OBJECTIVE To highlight important issues regarding the design, conduct, and reporting of exercise trials and to provide(More)
In earlier work, Jockusch, Propp, and Shor proved a theorem describing the limiting shape of the boundary between the uniformly tiled corners of a random tiling of an Aztec diamond and the more unpredictable ‘temperate zone’ in the interior of the region. The so-called arctic circle theorem made precise a phenomenon observed in random tilings of large Aztec(More)
The problem of counting monomer-dimer coverings of a lattice is a longstanding problem in statistical mechanics. It has only been exactly solved for the special case of dimer coverings in two dimensions ((Kas61), (TF61)). In earlier work, Stanley (Sta85) proved a reciprocity principle governing the number N(m,n) of dimer coverings of an m by n rectangular(More)
Louis Solomon showed that the group algebra of the symmetric group Sn has a subalgebra called the descent algebra, generated by sums of permutations with a given descent set. In fact, he showed that every Coxeter group has something that can be called a descent algebra. There is also a commutative, semisimple subalgebra of Solomon’s descent algebra(More)
We show that the set R(w0) of reduced expressions for the longest element in the hyperoctahedral group exhibits the cyclic sieving phenomenon. More specifically, R(w0) possesses a natural cyclic action given by moving the first letter of a word to the end, and we show that the orbit structure of this action is encoded by the generating function for the(More)