Palindromes in starlike trees

In this note, we obtain an upper bound on the maximum number of distinct non-empty palindromes in starlike trees. This bound implies, in particular, that there are at most 4 n distinct non-empty palindromes in a starlike tree with three branches each of length n. For such starlike trees labelled with a binary alphabet, we sharpen the upper bound to 4 n − 1 and conjecture that the actual maximum is 4 n − 2. It is intriguing that this simple conjecture seems difficult to prove, in contrast to the proof of the bound

Phylogenetic structure of Guinea-Bissau ethnic groups for mitochondrial DNA and Y chromosome genetic systems

The maternal and paternal genetic profile of Guineans is markedly sub-Saharan West African, with the majority of lineages belonging to L0-L3 mtDNA sub-clusters and E3a-M2 and E1-M33 Y chromosome haplogroups. Despite the sociocultural differences among Guinea-Bissau ethnic groups,marked by the supposedly strict admixture barriers, their genetic pool remains largely common. Their extant variation coalesces at distinct timeframes, from the initial occupation of the area to later inputs of people. Signs of recent expansion in mtDNA haplogroups L2a-L2c and NRY E3a-M2 suggest population growth in the equatorial western fringe, possibly supported by an early local agricultural centre, and to which the Mandenka and the Balanta people may relate. Non-West African signatures are traceable in less frequent extant haplogroups, fitting well with the linguistic and historical evidence regarding particular ethnic groups: the Papel and Felupe-Djola people retain traces of their putative East African relatives; U6 and M1b among Guinea-Bissau Bak-speakers indicate partial diffusion to Sahel of North African lineages; U5b1b lineages in Fulbe and Papel represent a link to North African Berbers, emphasizing the great importance of post-glacial expansions; exact matches of R1b-P25 and E3b1-M78 with Europeans likely trace back to the times of the slave trade.Orientadores: António Brehm e Richard Villem

Reading nonsense a journey through the writing of Edward Lear

In this thesis I have addressed some of the problems that have arisen in critical approaches to the nonsense works of Edward Lear from the late nineteenth century. I have entitled it “Reading Nonsense” because my central concern is with how best to apprehend the paradoxes inherent in literary nonsense, which inevitably raises interpretative questions. Because nonsense is a “basic type of communication” whose essence is “unresolved tension between [the] presence and absence of meaning” (Tigges, Anatomy 51), we are called upon either to “make sense of” that which claims to offer up no meaning or to surrender ourselves to meaninglessness. Broadly, critical approaches to nonsense fall into two classes: those that maintain that nonsense is not, in fact, “not sense”, but rather a kind of symbolic language that can be reconciled into meaning; and those which uphold the nonsensicality of nonsense, maintaining that certain ambiguities and paradoxes cannot be accounted for, and it is inappropriate to try to do so. In addition, Lear’s texts are situated in various traditions of writing for children and adults and in the distinctive setting of the Victorian era; and these cultural and literary influences play an important role in the interpretation and misinterpretation of nonsense. My first chapter comprises a mise en scène of the genre of literary nonsense; while in Chapter 2 I turn to the cultural backdrop of Lear’s nonsense in particular, and examine one of the claims frequently made in nonsense criticism: that Lear’s literary nonsense is distinctively “Victorian”. Chapter 3, “How to Read a Learian Limerick”, rests on the exegesis of nonsense that appears in Chapter 1, for here I propose a technique for reading Lear’s limericks that preserves both their “sensical” and nonsensical elements in contrast to critical analyses that attempt to reconcile the nonsense into a code. In Chapter 4 I examine Lear’s songs from the critical perspectives of nonsense and of romanticism. Finally, in conclusion, I consider the role and significance of humour in nonsense, and gesture towards further possible explorations, including in the appendix my essay on the nonsense poetry of South African writer Philip de Vos