Open versus closed surgical exposure of canine teeth that are displaced in the roof of the mouth

Background: Palatal canines are upper permanent canine (eye) teeth that have become displaced in the roof of the mouth. They are a frequently occurring anomaly, present in 2% to 3% of the population. Management of this problem is both time consuming and expensive and involves surgical exposure (uncovering) followed by fixed braces for 2 to 3 years to bring the canine into alignment within the dental arch. Two techniques for exposing palatal canines are routinely used in the UK: one method (the closed technique) involves orthodontically moving the canine into its correct position beneath the palatal mucosa and the second method (the open technique) involves orthodontically moving the canine into its correct position above the palatal mucosa. Objectives: To establish if clinical, patient centred and economic outcomes are different according to whether an ’open’ or ’closed’ technique is employed for uncovering palatal canines. Search strategy: MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials (CENTRAL) and the Cochrane Oral Health Group’s Trials Register were searched (to 29th February 2008). There were no restrictions with regard to publication status or language. Selection criteria: Patients receiving surgical treatment to correct upper palatally impacted canines.Therewas no restriction for age, presenting malocclusion or the type of active orthodontic treatment undertaken. Unilateral and bilaterally displaced canines were included. Trials including participants with craniofacial deformity/syndrome were excluded. Data collection and analysis: Two review authors independently and in duplicate assessed studies for inclusion. The Cochrane Collaboration statistical guidelines were to be followed for data synthesis

Experimental Status of BB Physics

A short summary is given of the current status of B physics. Reasons for physics beyond the Standard Model are discussed. Constraints on New Physics are given using measurements of B mixing, Bs mixing, and CP violation, along with |Vub. Future goals, and upcoming new experiments are also mentioned.Comment: Invited talk at X Mexican Workshop on Particles and Fields, Morelia, Michoacan, Mexico, Nov. 7-12, 2005; 16 pages and 12 figures; (added references

NP-complete Problems and Physical Reality

Can NP-complete problems be solved efficiently in the physical universe? I survey proposals including soap bubbles, protein folding, quantum computing, quantum advice, quantum adiabatic algorithms, quantum-mechanical nonlinearities, hidden variables, relativistic time dilation, analog computing, Malament-Hogarth spacetimes, quantum gravity, closed timelike curves, and "anthropic computing." The section on soap bubbles even includes some "experimental" results. While I do not believe that any of the proposals will let us solve NP-complete problems efficiently, I argue that by studying them, we can learn something not only about computation but also about physics.Comment: 23 pages, minor correction

Comparing linguistic judgments and corpus frequencies as windows on grammatical competence: A study of argument linearization in German clauses

We present an overview of several corpus studies we carried out into the frequencies of argument NP orderings in the midfield of subordinate and main clauses of German. Comparing the corpus frequencies with grammaticality ratings published by Keller’s (2000), we observe a “grammaticality–frequency gap”: Quite a few argument orderings with zero corpus frequency are nevertheless assigned medium–range grammaticality ratings. We propose an explanation in terms of a two-factor theory. First, we hypothesize that the grammatical induction component needs a sufficient number of exposures to a syntactic pattern to incorporate it into its repertoire of more or less stable rules of grammar. Moderately to highly frequent argument NP orderings are likely have attained this status, but not their zero-frequency counterparts. This is why the latter argument sequences cannot be produced by the grammatical encoder and are absent from the corpora. Secondly, we assumed that an extraneous (nonlinguistic) judgment process biases the ratings of moderately grammatical linear order patterns: Confronted with such structures, the informants produce their own “ideal delivery” variant of the to-be-rated target sentence and evaluate the similarity between the two versions. A high similarity score yielded by this judgment then exerts a positive bias on the grammaticality rating—a score that should not be mistaken for an authentic grammaticality rating. We conclude that, at least in the linearization domain studied here, the goal of gaining a clear view of the internal grammar of language users is best served by a combined strategy in which grammar rules are founded on structures that elicit moderate to high grammaticality ratings and attain at least moderate usage frequencies