Differential Reward Learning for Self and Others Predicts Self-Reported Altruism

In social environments, decisions not only determine rewards for oneself but also for others. However, individual differences in pro-social behaviors have been typically studied through self-report. We developed a decision-making paradigm in which participants chose from card decks with differing rewards for themselves and charity; some decks gave similar rewards to both, while others gave higher rewards for one or the other. We used a reinforcement-learning model that estimated each participant''s relative weighting of self versus charity reward. As shown both in choices and model parameters, individuals who showed relatively better learning of rewards for charity – compared to themselves – were more likely to engage in pro-social behavior outside of a laboratory setting indicated by self-report. Overall rates of reward learning, however, did not predict individual differences in pro-social tendencies. These results support the idea that biases toward learning about social rewards are associated with one''s altruistic tendencies.     

Separation of yeast proteasome subunits. Immunoreactivity with antibodies against ATP-dependent protease Ti from Escherichia coli

On two-dimensional gel electrophoresis, proteasomes (multicatalytic proteinase complexes) from the yeast Saccharomyces cerevisiae were separated into a characteristic set of approximately 20 components with molecular weights of 21,000 to 31,000 and isoelectric points of 3.5 to 7.5. The main components were isolated by reverse-phase high performance liquid chromatography on a TSK gel phenyl-5PW RP column and named YC1 to YC11, in order of their elution. Immuno-blot analysis showed that two components (YC1-alpha and YC1-beta) with molecular weights of 30,800 and 28,300 strongly cross-reacted with antibody against the P-component of ATP-dependent protease Ti from Escherichia coli, but no components were found to react with antibodies against the A-component of protease Ti or another ATP-dependent protease La (the Ion gene product) of Escherichia coli. These results indicate a structural relationship between eukaryotic proteasomes and bacterial ATP-dependent protease Ti.     

The significance of pollination time and frequency and of purity of pollen loads for seed set in Rhinanthus angustifolius (Scrophulariaceae) and Viscaria vulgaris (Caryophyllaceae)

Summary The effects of time of the day and frequency of application and of purity of artificially deposited pollen loads on fruiting and seed set were studied in Rhinanthus angustifolius (diurnally visited by bumblebees) and Viscaria vulgaris (diurnally visited by bumblebees, nocturnally by sphingid moths).Time of the day did not influence pollination success in either species. Increase of pollination frequency increased fruiting and seed set in Rhinanthus but had no affect on Viscaria. Five successive artificial pollinations were needed to achieve seed set equal to that observed naturally in Rhinanthus while a single artificial pollination was sufficient in Viscaria. Mixing Lupinus and Viscaria pollen did not reduce fruiting and seed set in Viscaria. The results are discussed in relation to observed seed sets in early and late flowers, and small and large patches of Viscaria vulgaris and among Rhinanthus flowers in populations of different densities.     

Phylogeny of Greya (Lepidoptera: Prodoxidae), based on nucleotide sequence variation in mitochondrial cytochrome oxidase I and II: congruence with morphological data

The phylogeny of Greya Busck (Lepidoptera: Prodoxidae) was inferred from nucleotide sequence variation across a 765-bp region in the cytochrome oxidase I and II genes of the mitochondrial genome. Most parsimonious relationships of 25 haplotypes from 16 Greya species and two outgroup genera (Tetragma and Prodoxus) showed substantial congruence with the species relationships indicated by morphological variation. Differences between mitochondrial and morphological trees were found primarily in the positions of two species, G. variabilis and G. pectinifera, and in the branching order of the three major species groups in the genus. Conflicts between the data sets were examined by comparing levels of homoplasy in characters supporting alternative hypotheses. The phylogeny of Greya species suggests that host-plant association at the family level and larval feeding mode are conservative characters. Transition/transversion ratios estimated by reconstruction of nucleotide substitutions on the phylogeny had a range of 2.0-9.3, when different subsets of the phylogeny were used. The decline of this ratio with the increase in maximum sequence divergence among taxa indicates that transitions are masked by transversions along deeper internodes or long branches of the phylogeny. Among transitions, substitutions of A-->G and T-->C outnumbered their reciprocal substitutions by 2-6 times, presumably because of the approximately 4:1 (77%) A+T-bias in nucleotide base composition. Of all transversions, 73%-80% were A<-->T substitutions, 85% of which occurred at third positions of codons; these estimates did not decrease with an increase in maximum sequence divergence of taxa included in the analysis. The high frequency of A<-->T substitutions is either a reflection or an explanation of the 92% A+T bias at third codon positions.      

Transference numbers, polyion mobilities, and charge fractions in aqueous solutions of lithium, sodium, and potassium dextransulfate

Results of Hittorf type transference number measurements are reported for aqueous solutions of lithium, sodium, and potassium dextransulfate (DS) in the concentration range 0.008-0.09 moles of sulfate groups per liter. The results for the polyion transference number are combined with equivalent conductance measurements reported earlier to calculate the polyion equivalent conductance, and the polyion charge fraction based on Wall's method. Our results show that the transference number of this high charge density polyion is larger than unity over the entire concentration range studied, and decreases monotonously with increasing concentration. The calculated charge fraction f of the polyion increases with increasing concentration, and at any concentration/decreases in the order LiDS > NaDS > KDS. A comparison between the conclusions derived from these transport experiments and from both mean and single ion activity measurements in dextransulfate solutions shows the considerable uncertainties involved in either of these methods, and emphasizes the need for the application of a variety of techniques, including spectroscopic techniques, to determine differential ion binding by polyions.