We conducted a two-year predator-exclusion study to assess the magnitude and timing of larval predation in non-outbreaking populations of a geometrid moth, Epirrita autumnata. Laboratory-produced newly hatched larvae were placed on the experimental trees which were assigned to five treatments within two larval densities: (1) all predators, including parasitoids, excluded by mesh bag, (2) birds excluded by cage, (3) ants excluded by glue ring, (4) birds and ants excluded, and (5) control without any predator exclusion. Thereafter, larvae were censused every 3-4 d throughout the five-instar larval period.Mortality of E. autumnata larvae in these populations was high and mostly due to natural enemies. In control trees, only ϳ10% of larvae survived, while survival was ϳ90% in mesh bags preventing all natural enemies. Bird exclusion significantly improved larval survival, as survival was almost three times higher in trees with cages than in those without cages. On the other hand, ant exclusion did not have any overall effects on larval survival, mostly because ants were only detected in about half of the trees without glue rings. Larvae survived longer in high-density trees from which ants were excluded, but the effect was masked by high mortality, unrelated to ant exclusion, in the late larval season. The results suggest that the effect of ant predation on survival of E. autumnata larvae may be spatially restricted and not important at a larger scale. The same result applies for crab spiders, as they caused high mortality in ϳ20% of the study trees. Our results emphasize the importance of considering the spatial scale as well as assessing the impact of multiple predators in order to detect predators affecting survival at the population level.Exclusion of all predation had a significantly stronger effect on larval survival than exclusion of birds alone. Further, mortality was highest during the late larval period, when parasitoids emerge. Thus, a large proportion of larval mortality was most likely due to parasitism. Our results suggest that predation by passerine birds and parasitism may contribute to maintenance of low E. autumnata densities by strong suppression of the number of larvae entering the pupal stage.

Finnish speaking adults categorized synthetic vowels, varying in the frequency of the second formant (F2), as either /y/ or /i/. Two subject groups emerged: "good" and "poor" categorizers. In a /i/ rating experiment, only the good categorizers could consistently label their best /i/ (the prototype, P), being low in the F2 continuum. Poor categorizers rated /i/'s with high F2 values as Ps. In a same/different (AX) discrimination experiment, using the individual Ps and nonprototypes (NPs), it was more difficult for good categorizers to detect small F2 deviations from the P than from an NP (the "perceptual magnet effect"). For poor categorizers, the opposite effect was found. The same stimuli were used to record the mismatch negativity (MMN), an ERP component reflecting preattentive detection of deviations from a standard sound. For the good categorizers the MMNs were lower for Ps than for NPs; for the poor categorizers the MMNs for Ps and NPs did not differ significantly. The results show that individual listeners behaved differently in categorization and goodness rating but in the same way in attentive (AX) discrimination, being the poorest at about the same F2 location. The perceptual magnet effect was indicated in the good categorizers both by behavioral and psychophysiological (MMN) discrimination data.

Regression analysis is the method of choice for the production of covariate-dependent reference limits. There are currently no recommendations on what sample size should be used when regression-based reference limits and confidence intervals are calculated. In this study we used Monte Carlo simulation to study a reference sample group of 374 age-dependent hemoglobin values. From this sample, 5000 random subsamples, with replacement, were constructed with 10–220 observations per sample. Regression analysis was used to estimate age-dependent 95% reference intervals for hemoglobin concentrations and erythrocyte counts. The maximum difference between mean values of the root mean square error and original values for hemoglobin was 0.05 g/L when the sample size was ≥60. The parameter estimators and width of reference intervals changed negligibly from the values calculated from the original sample regardless of what sample size was used. SDs and CVs for these factors changed rapidly up to a sample size of 30; after that changes were smaller. The largest and smallest absolute differences in root mean square error and width of reference interval between sample values and values calculated from the original sample were also evaluated. As expected, differences were largest in small sample sizes, and as sample size increased differences decreased. To obtain appropriate reference limits and confidence intervals, we propose the following scheme: (a) check whether the assumptions of regression analysis can be fulfilled with/without transformation of data; (b) check that the value of v, which describes how the covariate value is situated in relation to both the mean value and the spread of the covariate values, does not exceed 0.1 at minimum and maximum covariate positions; and (c) if steps 1 and 2 can be accepted, the reference limits with confidence intervals can be produced by regression analysis, and the minimum acceptable sample size will be ∼70.

The method is freely available at http://www.mtt.fi/AlignmentQuality/.

Background: Multiple sequence alignment is the foundation of many important applications in bioinformatics that aim at detecting functionally important regions, predicting protein structures, building phylogenetic trees etc. Although the automatic construction of a multiple sequence alignment for a set of remotely related sequences cause a very challenging and error-prone task, many downstream analyses still rely heavily on the accuracy of the alignments.