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Results for “uninformative prior”

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PubMed2025

A General Framework for Branch Length Estimation in Ancestral Recombination Graphs.

Inference of Ancestral Recombination Graphs (ARGs) is of central interest in the analysis of genomic variation. ARGs can be specified in terms of topologies and coalescence times. The coalescence times are usually estimated using an informative prior derived from coalescent theory, but this may generate biased estimates and can also complicate downstream inferences based on ARGs. Here we introduce, POLEGON, a novel approach for estimating branch lengths for ARGs which uses an uninformative prior. Using extensive simulations, we show that this method provides improved estimates of coalescence times and lead to more accurate inferences of effective population sizes under a wide range of demographic assumptions (population expansion, bottleneck, split, etc). It also improves other downstream inferences including estimates of mutation rates. We apply the method to data from the 1000 Genomes Project to investigate population size histories and differential mutation signatures across populations. We also estimate coalescence times in the HLA region, and show that they exceed 30 million years in multiple segments.

Ancestral Recombination Graph↗

PubMed1978

Odor and marijuana intoxication.

Assigned 48 volunteer adult males to four groups: a marijuana high dose, a marijuana low dose, a placebo, and a coltsfoot group. Each S participated in two 80-minute sessions; one involved listening to music, socializing, and smoking the drug, and the second was identical to the first with the addition of two extra placebo cigarettes which contained finely cut amounts of human hair. The odor of burning hair was rated previously as quite aversive by non-intoxicated Ss. Contrary to expectation, Ss in the odor condition indicated on self-ratings that they became significantly more intoxicated after the smoking of the hair cigarette. The opposite effect was found with a pulse rate measure. An additional 24 Ss were divided into high and low dose marijuana groups and run in an odor session, in which they were informed prior to smoking of the hair content. Heart rate for these Ss decreased significantly more than for the comparable uninformed Ss, although self-ratings continued to reflect increased intoxication.

Adult↗

PubMed1979

The influence of the labeling of pictures of "borderline meaningfulness" on recall and recognition.

An attempt was made to enhance (by means of instruction) the verbal labeling and recall of schematic pictures which uninformed Ss tended to perceive as senseless. Sixty-nine male and female undergraduate students in psychology, about 19 years of age, took part in the experiment. Ss were confronted with 16 schematic pictures half of which referred to a predefined semantical category. In Condition I Ss were informed in advance that some of the pictures belonged to the predefined category. In Condition II the pictures were presented as senseless. In Condition III information about the belonging of some of the items to one semantical category was postponed until just prior to free recall. The results indicated that verbal labeling of the pictures involved was stimulated by appropriate instruction, enhancing later free recall. However, the critical information had to be given prior to actual learning. In a subsequent test for recognition no differences were observed between the conditions.

Female↗