Publications

Abstract

Brain processing depends on the interactions between neuronal groups. Those interactions are governed by the pattern of anatomical connections and by yet unknown mechanisms that modulate the effective strength of a given connection. We found that the mutual influence among neuronal groups depends on the phase relation between rhythmic activities within the groups. Phase relations supporting interactions between the groups preceded those interactions by a few milliseconds, consistent with a mechanistic role. These effects were specific in time, frequency, and space, and we therefore propose that the pattern of synchronization flexibly determines the pattern of neuronal interactions.

Abstract

The three Olutec stories from Oluta, Veracruz, werenarrated by Antonio Asistente Maldonado. Roberto Zavala presents amorpheme-by-morpheme analysis of the texts with a sketch of the majorgrammatical and typological features of this language. Olutec is spoken bythree dozen speakers. The grammatical structure of this language has not beendescribed before. The sketch contains information on verb and noun morphology,verb dasses, clause types, inverse/direct patterns, grammaticalizationprocesses, applicatives, incorporation, word order type, and discontinuousexpressions. The stories presented here are the first Olutec texts everpublished. The motifs of the stories are well known throughout Middle America.The story of "the Rabbit who wants to be big" explains why one of the mainprotagonists of Middle American folktales acquired long ears. The story of "theDevil who is inebriated by the people of a village" explains how theinhabitants of a village discover the true identity of a man who likes to dancehuapango and decide to get rid of him. Finally the story of "theshit-sellers" presents two compadres, one who is lazy and the otherone who works hard. The hard-worker asks the lazy compadre how he surviveswithout working. The latter lies to to him that he sells shit in theneighboring village. The hard-working compadre decides to become a shit-sellerand in the process realizes that the lazy compadre deceived him. However, he islucky and meets with the Devil who offers him money in compensation for havingbeen deceived. When the lazy compadre realizes that the hard-working compadrehas become rich, he tries to do the same business but gets beaten in theprocess.

Abstract

Genome-wide association studies using thousands to hundreds of thousands of single nucleotide polymorphism (SNP) markers and region-wide association studies using a dense panel of SNPs are already in use to identify disease susceptibility genes and to predict disease risk in individuals. Because these tasks become increasingly important, three different data sets were provided for the Genetic Analysis Workshop 15, thus allowing examination of various novel and existing data mining methods for both classification and identification of disease susceptibility genes, gene by gene or gene by environment interaction. The approach most often applied in this presentation group was random forests because of its simplicity, elegance, and robustness. It was used for prediction and for screening for interesting SNPs in a first step. The logistic tree with unbiased selection approach appeared to be an interesting alternative to efficiently select interesting SNPs. Machine learning, specifically ensemble methods, might be useful as pre-screening tools for large-scale association studies because they can be less prone to overfitting, can be less computer processor time intensive, can easily include pair-wise and higher-order interactions compared with standard statistical approaches and can also have a high capability for classification. However, improved implementations that are able to deal with hundreds of thousands of SNPs at a time are required.