We present a new shorter and simplified proof for the undecidability of the mortality problem in matrix semigroups, originally proved by Paterson in 1970. We use the clever coding technique introduced by Paterson to achieve also a new result, the undecidability of the vanishing (left) upper corner. Since our proof for the undecidability of the mortality problem uses only 8 matrices, a new bound...

One of the main points of the paper is the importance of addressing conflicts of interest in a way that will not reduce the information flow to financial markets. While a number of remedies are already in place, putting the bubble and fraud into a somewhat broader perspective, in order to avoid further remedies that might do more harm than good, could be worthwhile. Although one would not want ...

Forty-one specimens taken from lesions in the post-cricoid region of patients with the Paterson-Kelly syndrome have been examined. Most webs consist of normal oesophageal mucosa which may be associated with underlying muscle and nerve lesions. Strictures also show a chronic non-specific inflammation often with epithelial changes and sometimes squamous carcinoma. Other lesions observed clinicall...

The short-scan case in fan-beam computed tomography requires the introduction of a weighting function to handle redundant data. Parker introduced such a weighting function for a scan over pi plus the opening angle of the fan. In this article we derive a general class of weighting functions for arbitrary scan angles between pi plus fan angle and 2pi (over-scan). These weighting functions lead to...

helping to create a low-carbon economy”. While companies now scramble to assemble their green credentials, Wal-Mart are already raising the stakes, with Leo Scott addressing a meeting in the UK this month at the invitation of Prince Charles. He promised to take nonrenewable energy “off our shelves and out of the lives of our customers”. “Forgive the jargon, but we think sustainability is cool,”...

NOTE: *These temperature ranges will apply to the majority of media for which the material is potentially recommended. With some media however, the service temperature range may be significantly different. ALWAYS TEST UNDER ACTUAL SERVICE CONDITIONS. Nitrile (General Service) -34°C to 121°C (-30°F to 250°F)* Nitrile (Low Temperature) -55°C to 107°C (-65°F to 225°F)* Hydrogenated Nitrile -32°C t...

Certificateless public key encryption (CLE) and certificate based encryption (CBE) are two novel public key cryptographic primitives requiring no authenticity verification of the recipient’s public key. Both of them are motivated to simultaneously solve the heavy certificate management problem inherent in the traditional public key encryption (PKE) and the key escrow problem inherent in the ide...

s. Vaccaro A, Kabashi E, Patten K, Aggad D, Drapeau P, Parker JA, Drug Discovery for ALS, ALS Association USA, 2012, Washington, DC, USA. Vaccaro A, Kabashi E, Patten K, Aggad D, Drapeau P, Parker JA. Chemical genetic screens for in vivo TDP-43 modifiers and ALS drug discovery. 22nd International symposium on ALS/MND, 2011. Sydney, Australia Vaccaro A, Tauffenberger A, Parker JA. Development of...