Understanding a user’s motivations provides valuable information beyond the ability to recommend items. Quite often this can be accomplished by perusing both ratings and review texts, since it is the latter where the reasoning for specific preferences is explicitly expressed. Unfortunately matrix factorization approaches to recommendation result in large, complex models that are difficult to in...

Pointwise mutual information (PMI), a simple measure of lexical association, is part of several algorithms used as models of lexical semantic memory. Typically, it is used as a component of more complex distributional models rather than in isolation. We show that when two simple techniques are applied—(1) down-weighting co-occurrences involving lowfrequency words in order to address PMI’s so-ca...

We study a dynamic coordination process in which agents are uncertain about the actions of their fellow agents, and anticipate strategically relevant information. Because of the uncertainty and learning, (ir)reversibility of actions has important strategic consequences. We find that the reversibility option can either enhance or hamper efficient coordination, and we characterize the direction o...

We extend Post’s programme to finite levels of the Ershov hierarchy of ∆2 sets, and characterise, in the spirit of Post [9], the degrees of the immune and hyperimmune d.c.e. sets. We also show that no properly d.c.e. set can be hh-immune, and indicate how to generalise these results to n-c.e. sets, n > 2.

For optical studies of boiling heat transfer process, it is essential that the refractive index and its dependence on temperature for the test liquid be known. In this work a simple set-up was built to measure the refractive index of Fluorinert Liquid PF-5060 with temperature compensation and temperature control. The pinhole laser light beam was used for determining the refraction angle. The re...

Since CO(2) is carbonic acid gas, it will decrease the pH if added to water. Therefore, a simple test can determine whether CO(2) is present in a gas mixture. If the pH of gassed water does not change significantly, then CO(2) is not present in the gas.

Weprovide a simple set of sufficient conditions for theweak convergence of discrete-time, discrete-state Galton–Watson branching processes with immigration to continuous-time, continuous-state branching processes with immigration.

We show that in the c.e. weak truth table degrees if b < c then there is an a which contains no hypersimple set and b < a < c. We also show that for every w < c in the c.e. wtt degrees such that w is hypersimple, there is a hypersimple a such that w < a < c. On the other hand we know that there are intervals which contain no hypersimple set.

In this research, a metal oxide nanocatalyst of ZnO supported copper oxide is reported as a highly efficient recyclable catalyst for the chemoselective synthesis of 1,1-diacetates. The catalyst was synthesized by co-precipitation method and characterized by XRD, BET specific surface area, ESEM, EDS and TEM analysis. A wide range of aldehydes, including aromatic and aliphatic aldehydes were conv...