Specific-to-General Learning for Temporal Events with Application to Learning Event Definitions from Video

We develop, analyze, and evaluate a novel, supervised, specific-to-general learner for a simple temporal logic and use the resulting algorithm to learn visual event definitions from video sequences. First, we introduce a simple, propositional, temporal, event-description language called AMA that is sufficiently expressive to represent many events yet sufficiently restrictive to support learning. We then give algorithms, along with lower and upper complexity bounds, for the subsumption and generalization problems for AMA formulas. We present a positive-examples--only specific-to-general learning method based on these algorithms. We also present a polynomial-time--computable ``syntactic'' subsumption test that implies semantic subsumption without being equivalent to it. A generalization algorithm based on syntactic subsumption can be used in place of semantic generalization to improve the asymptotic complexity of the resulting learning algorithm. Finally, we apply this algorithm to the task of learning relational event definitions from video and show that it yields definitions that are competitive with hand-coded ones

HPV-18 transformed cells fail to arrest in G1 in response to quercetin treatment

Previous work with primary human keratinocytes demonstrated that quercetin, a potent mutagen found in high levels in bracken fern (Pteridium aquilinum), arrested cells in G1 with concomitant elevation of the cyclin-dependent kinase inhibitor (cdki) p27Kip1. Expression of the human papillomavirus type 16 (HPV-16) E6 and E7 oncoproteins, under transcriptional control of a heterologous promoter, in transformed keratinocytes failed to abrogate this arrest [Beniston, R., Campo, M.S., 2003. Quercetin elevates p27(Kip1) and arrests both primary and HPV-16 E6/E7 transformed human keratinocytes in G1. Oncogene 22, 5504–5514]. Given the link between papillomavirus infection, bracken fern in the diet and cancer of the oesophagus in humans, we wished to investigate further whether cells transformed by the whole genome of HPV-16 or HPV-18, with E6 and E7 under the transcriptional control of their respective homologous promoters, would be similarly arrested in G1 by quercetin. In agreement with earlier work, quercetin arrested HPV-16 transformed cells in G1 with an increase in the cyclin-dependent kinase inhibitor p27Kip1. However, HPV-18 transformed cells did not arrest after quercetin treatment. The failure of HPV-18 transformed cells to arrest in G1 was linked to the up-regulation of the HPV-18 long control region (LCR) by quercetin, maintaining high expression of the viral transforming proteins. Transcriptional up-regulation of the HPV-18 LCR was mediated by a “quercetin responsive element” homologous to the one identified previously in the bovine papillomavirus type 4 (BPV-4) LCR

Discrete time piecewise affine models of genetic regulatory networks

We introduce simple models of genetic regulatory networks and we proceed to the mathematical analysis of their dynamics. The models are discrete time dynamical systems generated by piecewise affine contracting mappings whose variables represent gene expression levels. When compared to other models of regulatory networks, these models have an additional parameter which is identified as quantifying interaction delays. In spite of their simplicity, their dynamics presents a rich variety of behaviours. This phenomenology is not limited to piecewise affine model but extends to smooth nonlinear discrete time models of regulatory networks. In a first step, our analysis concerns general properties of networks on arbitrary graphs (characterisation of the attractor, symbolic dynamics, Lyapunov stability, structural stability, symmetries, etc). In a second step, focus is made on simple circuits for which the attractor and its changes with parameters are described. In the negative circuit of 2 genes, a thorough study is presented which concern stable (quasi-)periodic oscillations governed by rotations on the unit circle -- with a rotation number depending continuously and monotonically on threshold parameters. These regular oscillations exist in negative circuits with arbitrary number of genes where they are most likely to be observed in genetic systems with non-negligible delay effects.Comment: 34 page

Burns, Fern (Campbell) oral history interview

Fern Alice Burns was born in Portland, Maine on September 20, 1944. She grew up on a farm in West Buxton. Burns attended school with deaf children because her mother was an accountant for the deaf school in Portland. They later moved to Augusta where she and her brother attended high school. After high school she attended Boston University for one year and in 1963 she moved to Washington to work for Stanley R. Tupper, who was like a godfather to her. She ended up working for Congressman George M. Walhauser, and was then hired by George Mitchell as a case worker at Muskie’s office in January 1965. In April 1971, Fern left Muskie’s office to go back to school and work for the U.S. Postal Service and with the Universal Postal Union (UPU). She got her degree from the University of Maryland in 1982. Fern worked on the 1968 campaign doing speech production and traveling a lot for Muskie

Dawai: an R Package for Discriminant Analysis With Additional Information

The incorporation of additional information into discriminant rules is receiving in- creasing attention as the rules including this information perform better than the usual rules. In this paper we introduce an R package called dawai, which provides the functions that allow to de ne the rules that take into account this additional information expressed in terms of restrictions on the means, to classify the samples and to evaluate the accuracy of the results. Moreover, in this paper we extend the results and de nitions given in previous papers (Fern andez, Rueda, and Salvador 2006, Conde, Fern andez, Rueda, and Salvador 2012, Conde, Salvador, Rueda, and Fern andez 2013) to the case of unequal co- variances among the populations, and consequently de ne the corresponding restricted quadratic discriminant rules. We also de ne estimators of the accuracy of the rules for the general more than two populations case. The wide range of applications of these pro- cedures is illustrated with two data sets from two di erent elds, i.e., biology and pattern recognition.Spanish Ministerio de Ciencia e Innovación (MTM2012-37129