may be many years in the past. The accuracy of reporting on sensitive matters relating to sexual behavior can also shift as the culture changes, and that accuracy may vary with age. Because, by definition, self-reports of the initiation of sexual activity cannot be externally validated, the scientific literature has necessarily focused on the consistency and reliability of reporting, through tw...

The hippocampus is thought to be involved in episodic memory formation by reactivating traces of waking experience during sleep. Indeed, the joint firing of spatially tuned pyramidal cells encoding nearby places recur during sleep. We found that the sleep cofiring of rat CA1 pyramidal cells encoding similar places increased relative to the sleep session before exploration. This cofiring increas...

∗I would like to thank the editors Kathrin and Peter and an anonymous reviewer of Philosophy Compass for suggestions to improve the final version. Further thanks go to my colleagues Paul Egré, David Ripley and Robert van Rooij and the Australian philosopher and paraconsistent logician Dominic Hyde for discussion and comments at different stages. Thanks also to Pablo Visiers. This work was done ...

Another way to get an upper bound is to use the big formula for the determinant from p. 212. Notice that, for any 5 by 5 matrix, there are 5! = 120 terms in the sum. When all entries of A are smaller than 1 (in absolute value), it must be the case that each of the 120 terms in the sum is smaller than 1 (in absolute value). Therefore, the whole sum (which is just the determinant), must be no big...

2. Problem 3.1.20. Let S be a subspace of Rn. Explain what (S⊥)⊥ = S means and why it is true. Answer: First, (S⊥)⊥ is the orthogonal complement of S⊥, which is itself the orthogonal complement of S, so (S⊥)⊥ = S means that S is the orthogonal complement of its orthogonal complement. To show that it is true, we want to show that S is contained in (S⊥)⊥ and, conversely, that (S⊥)⊥ is contained i...

Objective: The aim of this study was to identify factors related to the prevalence of caries in 12-year-old schoolchildren. Methods: A cross-sectional study was carried out using a representative sample (n = 1217) of the population of 12-yearold schoolchildren in Galiza (northwest Spain). Independent variables were measured through a questionnaire, and dependent variables were determined throug...