A fault-tolerant clock

Computers must operate correctly even though one or more of components have failed. Electronic clock has been designed to be insensitive to occurrence of faults; it is substantial advance over any known clock

Abstracts of NASA-ASRDI publications relevant to aerospace safety research

Abstracts covering the following areas are presented: (1) oxygen technology; (2) fire safety; (3) accidents/incidents; (4) toxic spills; (5) aircraft safety; (6) structural failures; (7) nuclear systems; (8) fluid flow; and (9) zero gravity combustion

Is executive impairment associated with schizophrenic syndromes? A meta-analysis

Original article can be found at: http://journals.cambridge.org/ Copyright Cambridge University Press. DOI: 10.1017/S0033291708003887A key neuropsychological proposal in schizophrenia is that negative and disorganization symptoms are associated with different patterns of impairment on executive tasks. Reporting correlations between positive, negative or disorganization symptoms and any type of executive test were meta-analysed. The influence of moderating factors was also examined, including age, treatment and stage of illness and whether symptoms were relapsing or persistent. The magnitudes of the correlations were compared with those for general intellectual impairment. Pooled correlations between executive impairment and both negative symptoms and disorganization were significant in the small-to-moderate range. That for positive symptoms (‘reality distortion’), however, was close to zero. The pattern of correlations among different executive tests differed significantly for negative symptoms and disorganization. Patients with stable clinical pictures showed significantly higher correlations with executive impairment than those with relapsing and remitting illnesses. Both negative symptoms and disorganization also correlated significantly with general intellectual function as indexed by current IQ. Meta-analysis supports the view that negative symptoms and disorganization are associated with partially dissociable patterns of executive impairment. However, co-existent general intellectual impairment has been an important confounding factor in the studies to date.Peer reviewe

Effect of polaronic charge transfer on band alignment at the Cu/TiO2 interface

We present a first principles investigation into the electronic properties of an extended interface between rutile TiO2 and Cu. We show that owing to the highly polarizable nature of TiO2, the interface is unstable to the spontaneous formation of small electron polarons at the interface. The resulting dipole leads to an increase in the conduction band offset by 0.4 eV and the presence of a band of occupied states related to Ti d states 1.4 eV below the Fermi energy. This effect should be expected more generally at interfaces between highly polarizable oxides and metals but is missed by standard first principles approaches. Given the ubiquitous nature of such interfaces, this previously overlooked effect may have important implications for diverse applications across science and technology