Universally programmable quantum cellular automaton.

We discuss the role of classical control in the context of reversible quantum cellular automata. Employing the structure theorem for quantum cellular automata, we give a general construction scheme to turn an arbitrary cellular automaton with external classical control into an autonomous one, thereby proving the computational equivalence of these two models. We use this technique to construct a universally programmable cellular automaton on a one-dimensional lattice with single cell dimension 12.

White matter lesions and season of birth of patients with bipolar affective disorder.

OBJECTIVE: It is established that patients with bipolar disorder have an excess of births in winter or early spring. The authors investigated a link between season of birth and white matter lesions with magnetic resonance imaging (MRI). METHOD: T(2)-weighted and proton density MRI scans were examined for 79 patients with bipolar disorder (DSM-IV) for the presence of deep subcortical and periventricular white matter lesions. The birth seasons of patients with white matter lesions were compared with those of the general population. RESULTS: Thirteen subjects exhibited deep subcortical white matter lesions, of whom nine (69.2%) were born in the winter months (January to March). Seven of these patients remained symptomatic, despite adequate treatment for more than 2 years. CONCLUSIONS: Birth season, illness outcome, and deep subcortical white matter lesions appear to be closely linked. Deep subcortical white matter lesions may be a marker of a toxic or infective insult in utero.

Cerebral white matter lesions in bipolar affective disorder: relationship to outcome.

BACKGROUND: Twenty per cent of patients with bipolar affective disorder suffer an illness that responds inadequately to treatment and has a poor outcome. Many patients, but not all, with bipolar disorder show white matter abnormalities on T(2)-weighted magnetic resonance imaging (MRI). AIMS: To explore the hypothesis that white matter abnormalities on MRI are seen more frequently in subjects whose illness has a poor outcome compared with those with a good outcome or controls. METHOD: Two groups of age- and gender-matched patients with bipolar disorder (14 with a good outcome and 15 with a poor outcome) and 15 controls, aged 20-65 years, were studied. Axial T(2)-weighted MRI scans were examined for the presence and severity of white matter abnormalities. RESULTS: Significantly more poor outcome group members had deep subcortical punctate, but not periventricular, white matter hyperintensities than the good outcome group (P:=0.035) or controls (P:=0.003) and these abnormalities were of greater severity (P:=0.030 and P:<0.014, respectively). CONCLUSIONS: Subcortical white matter lesions are associated with poor outcome bipolar disorder.