The missense of smell: functional variability in the human odorant receptor repertoire.

Humans have ~400 intact odorant receptors, but each individual has a unique set of genetic variations that lead to variation in olfactory perception. We used a heterologous assay to determine how often genetic polymorphisms in odorant receptors alter receptor function. We identified agonists for 18 odorant receptors and found that 63% of the odorant receptors we examined had polymorphisms that altered in vitro function. On average, two individuals have functional differences at over 30% of their odorant receptor alleles. To show that these in vitro results are relevant to olfactory perception, we verified that variations in OR10G4 genotype explain over 15% of the observed variation in perceived intensity and over 10% of the observed variation in perceived valence for the high-affinity in vitro agonist guaiacol but do not explain phenotype variation for the lower-affinity agonists vanillin and ethyl vanillin

The Ontogenetic Osteohistology of Tenontosaurus tilletti

Tenontosaurus tilletti is an ornithopod dinosaur known from the Early Cretaceous (Aptian-Albian) Cloverly and Antlers formations of the Western United States. It is represented by a large number of specimens spanning a number of ontogenetic stages, and these specimens have been collected across a wide geographic range (from central Montana to southern Oklahoma). Here I describe the long bone histology of T. tilletti and discuss histological variation at the individual, ontogenetic and geographic levels. The ontogenetic pattern of bone histology in T. tilletti is similar to that of other dinosaurs, reflecting extremely rapid growth early in life, and sustained rapid growth through sub-adult ontogeny. But unlike other iguanodontians, this dinosaur shows an extended multi-year period of slow growth as skeletal maturity approached. Evidence of termination of growth (e.g., an external fundamental system) is observed in only the largest individuals, although other histological signals in only slightly smaller specimens suggest a substantial slowing of growth later in life. Histological differences in the amount of remodeling and the number of lines of arrested growth varied among elements within individuals, but bone histology was conservative across sampled individuals of the species, despite known paleoenvironmental differences between the Antlers and Cloverly formations. The bone histology of T. tilletti indicates a much slower growth trajectory than observed for other iguanodontians (e.g., hadrosaurids), suggesting that those taxa reached much larger sizes than Tenontosaurus in a shorter time

Why are Depressive Individuals Indecisive? Different Modes of Rumination Account for Indecision in Non-clinical Depression

Individuals with depressive symptoms tend to adopt an abstract-analytical (A-A) rather than a concrete-experiential (C-E) mode of rumination. A large body of evidence shows that this leads to many deficits that are associated with depression (Watkins in Psychol Bull 134:163–206, 2008). In two studies, the present research examined whether indecision in a non-clinical population could also result from the mode of rumination adopted. In the first study, 174 participants completed measures of depressive symptoms, rumination, decision-making styles and indecision. The results of this study showed that indecision and one dysfunctional decision-making style (hyper-vigilance) significantly correlated with A-A rumination, even when controlling for depression. In a second study, 71 participants with mild to severe depressive symptoms (MSDs) and 49 participants with no to minimal depressive symptoms were trained to adopt either an A-A or a C-E rumination mode, and subsequently requested to make 10 choices. Consistent with the results of the first study, the results of the second study showed that participants in the A-A condition took longer to make their choice compared to participants in the C-E condition, irrespective of their level of depression. Moreover, the group of participants with MSDs experienced slightly more difficulty in decision making when they were in the A-A mode than in the C-E mode. This suggests that the A-A rumination mode could be an antecedent of indecision, whereas the C-E mode predicts its reduction. These interpretations are in line with the idea that A-A rumination is maladaptive and C-E rumination is adaptive