Probabilistic matching pursuit with Gabor dictionaries

We propose a probabilistic extension of the matching pursuit adaptive signal processing algorithm introduced by Mallat and others. In adaptive signal processing, signals are expanded in terms of a large linearly dependent `dictionary' of functions rather than in terms of an orthonormal basis. Matching pursuit is a simple greedy algorithm for generating an expansion of a given signal. In probabilistic matching pursuit multiple random expansions are obtained as estimates for a given signal. The new algorithm is illustrated in the context of signal denoising. Although most of the random expansions generated by probabilistic matching pursuit are poorer estimates for the signal than those obtained by matching pursuit, our final estimate, obtained as an expected value computed by means of an ergodic average, can improve the result obtained by MP in some denoising situations. One of the major underlying ideas is a novel notion of coherence between a signal and the dictionary. Several simulated examples are presented.Fil: Ferrando, Sebastian Esteban. Ryerson Polytechnic University; CanadáFil: Doolittle, E.J.. University of Toronto; CanadáFil: Bernal, A. J.. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Física; ArgentinaFil: Bernal, Luis. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Física; Argentin

Size Doesn't Matter: Towards a More Inclusive Philosophy of Biology

notes: As the primary author, O’Malley drafted the paper, and gathered and analysed data (scientific papers and talks). Conceptual analysis was conducted by both authors.publication-status: Publishedtypes: ArticlePhilosophers of biology, along with everyone else, generally perceive life to fall into two broad categories, the microbes and macrobes, and then pay most of their attention to the latter. ‘Macrobe’ is the word we propose for larger life forms, and we use it as part of an argument for microbial equality. We suggest that taking more notice of microbes – the dominant life form on the planet, both now and throughout evolutionary history – will transform some of the philosophy of biology’s standard ideas on ontology, evolution, taxonomy and biodiversity. We set out a number of recent developments in microbiology – including biofilm formation, chemotaxis, quorum sensing and gene transfer – that highlight microbial capacities for cooperation and communication and break down conventional thinking that microbes are solely or primarily single-celled organisms. These insights also bring new perspectives to the levels of selection debate, as well as to discussions of the evolution and nature of multicellularity, and to neo-Darwinian understandings of evolutionary mechanisms. We show how these revisions lead to further complications for microbial classification and the philosophies of systematics and biodiversity. Incorporating microbial insights into the philosophy of biology will challenge many of its assumptions, but also give greater scope and depth to its investigations

Identification of γ-type hordeins in barley

AbstractThe barley mutant Risϕ 56 has a deletion of at least 85 kb of DNA at the Hor 2 locus, resulting in the absence from the seeds of almost all of the major B hordein group of storage proteins. We have purified two fractions containing the three remaining ‘B hordein-like’ bands and determined their N-terminal amino acid sequences. One fraction, containing the two bands with higher Mr, gave a single major N-terminal sequence which was closely related to those reported for γ-type prolamins of wheat and rye. The sequence of the third band was also homologous with those of the γ-type prolamins, but less closely so. We consider that the γ-type prolamins are most closely related to the ancestral S-rich prolamins of the Triticeae, and this is the first report of their presence in barley