University of Turku

About: University of Turku is a education organization based out in Turku, Finland. It is known for research contribution in the topics: Population & Galaxy. The organization has 16296 authors who have published 45124 publications receiving 1505428 citations. The organization is also known as: Turun yliopisto & Åbo universitet.

Semirings, Automata, Languages

Abstract: I. Linear Algebra.- 1. Semirings and Power Series.- 2. Convergence, Equations and Identities.- 3. Strong Convergence and Cycle-Free Power Series.- 4. Matrices, Linear Systems and Identities.- 5. Semirings with Particular Properties.- 6. Morphisms and Representations.- II. Automata.- 7. Automata in Terms of Matrices.- 8. Rational Power Series and Decidability.- 9. Rational Transductions.- 10. Pushdown Automata.- 11. Abstract Families of Power Series.- 12. Substitutions.- 13. Reset Pushdown Automata and Counter Automata.- III. Algebraic Systems.- 14. Algebraic Series and Context-Free Languages.- 15. The Super Normal Form.- 16. Commuting Variables: Decidability and Parikh's Theorem.- Historical and Bibliographical Remarks.- References.- Symbol Index.

Alien predators are more dangerous than native predators to prey populations.

Abstract: Alien predators are widely considered to be more harmful to prey populations than native predators. To evaluate this expectation, we conducted a meta-analysis of the responses of vertebrate prey in 45 replicated and 35 unreplicated field experiments in which the population densities of mammalian and avian predators had been manipulated. Our results showed that predator origin (native versus alien) had a highly significant effect on prey responses, with alien predators having an impact double that of native predators. Also the interaction between location (mainland versus island) and predator origin was significant, revealing the strongest effects with alien predators in mainland areas. Although both these results were mainly influenced by the huge impact of alien predators on the Australian mainland compared with their impact elsewhere, the results demonstrate that introduced predators can impose more intense suppression on remnant populations of native species and hold them further from their predator-free densities than do native predators preying upon coexisting prey.

Nanomaterials and supercritical fluids

Abstract: The interest in the preparation and application of nanometer size materials is increasing since they can exhibit properties of great industrial interest. Several techniques have been proposed to produce nanomaterials using supercritical fluids. These processes, taking advantage of the specific properties of supercritical fluids, are generally flexible, more simplified and with a reduced enviromental impact. The result is that nanomaterials with potentially better performances have been obtained. We propose a critical review of the supercritical based techniques applied to the production of nanoparticles, nanofibers, nanowires, nanotubes, nanofilms and nanostructured materials. The most relevant characteristics of each process and the kind of nanomaterial that can be produced are highlighted.

Intestinal Integrity and Akkermansia muciniphila, a Mucin-Degrading Member of the Intestinal Microbiota Present in Infants, Adults, and the Elderly

Abstract: Fluorescence in situ hybridization and real-time PCR analysis targeting the 16S rRNA gene of Akkermansia muciniphila were performed to determine its presence in the human intestinal tract. These techniques revealed that an A. muciniphila-like bacterium is a common member of the human intestinal tract and that its colonization starts in early life and develops within a year to a level close to that observed in adults (10(8) cells/g) but decreases (P < 0.05) in the elderly.