Sean Clark

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Quantum computations that involve only Clifford operations are classically simulable despite the fact that they generate highly entangled states; this is the content of the Gottesman-Knill theorem. Here we isolate the ingredients of the theorem and provide generalisations of some of them with the aim of identifying new classes of simulable quantum(More)
OBJECTIVE To determine the incidence of mediastinal shift on chest X-ray due to pneumothorax. METHODS A retrospective chart review was undertaken of all patients with pneumothorax presenting to the ED over the period 1 January 1995 to 31 December 1999. The primary outcome was mediastinal shift on initial CXR. The incidence of clinical tension pneumothorax(More)
In this study the environmental impact of consolidated rice farms (CF) - farms which have been integrated to increase the mechanization index - and traditional farms (TF) - small farms with lower mechanization index - in Guilan Province, Iran, were evaluated and compared using Life cycle assessment (LCA) methodology and adaptive neuro-fuzzy inference system(More)
<i>ColourNet</i> is a digital art system composed of a set interactive and interacting artworks. Although the artworks are able to work independently, they can also operate together to provide enhanced possibilities for human interaction and creative participation. We describe the <i>ColourNet</i> digital art system and demonstrate how people can interact(More)
Structural theorems regarding linear preservers of the higher rank numerical ranges are proved for the real linear space of bounded selfadjoint operators or the complex linear space of bounded linear operators acting on a Hilbert space. It is shown that the linear preservers of rank k-numerical ranges must be of the standard form: unitary similarity or(More)
Let M n be the semigroup of n × n complex matrices under the usual multiplication, and let S be different subgroups or semigroups in M n including the (special) unitary group, (special) general linear group, the semigroups of matrices with bounded ranks. Suppose Λ k (A) is the rank-k numerical range and r k (A) is the rank-k numerical radius of A ∈ M n.(More)