Function generator eliminates necessity of series summation

Diode generator using four building-block circuits produces complex waveforms without the necessity of series summation. This highly specialized method of producing complex waveforms requires less power than present methods and uses simpler circuitry

Comparative psychometrics: establishing what differs is central to understanding what evolves

Cognitive abilities cannot be measured directly. What we can measure is individual variation in task performance. In this paper, we first make the case for why we should be interested in mapping individual differences in task performance on to particular cognitive abilities: we suggest that it is crucial for examining the causes and consequences of variation both within and between species. As a case study, we examine whether multiple measures of inhibitory control for non-human animals do indeed produce correlated task performance; however, no clear pattern emerges that would support the notion of a common cognitive ability underpinning individual differences in performance. We advocate a psychometric approach involving a three-step programme to make theoretical and empirical progress: first, we need tasks that reveal signature limits in performance. Second, we need to assess the reliability of individual differences in task performance. Third, multi-trait multi-method test batteries will be instrumental in validating cognitive abilities. Together, these steps will help us to establish what varies between individuals that could impact their fitness and ultimately shape the course of the evolution of animal minds. Finally, we propose executive functions, including working memory, inhibitory control and attentional shifting, as a sensible starting point for this endeavour

The Influence of Warning Label Presentation in Memory Recognition of Aging Adults

Research indicates that hundreds of thousands of people are injured each year as a result of poor communication between medical personnel, warning label information, and consumers when taking over the counter or prescription medication. Typically, as adult\u27s age, they are increasingly responsible for remembering the hazards of taking medications. If inadequate information exists in memory in regards to side effects, dosage, and other warnings, the likelihood of improper usage will increase. Because aging adults typically have a reduction in cognitive resources, it was hypothesized that older adults would require the aid of additional warning information to assist in the retrieval process of this information. Therefore, it was predicted that aging adults will be able to retrieve information at a better performance level with a redundant set of text and pictorial information as it relates to warning labels than younger adults

Sex estimation in forensic anthropology: a test of the Klales et al. (2012) method with implications of asymmetry

Thesis (M.A.) University of Alaska Fairbanks, 2016A sample of 204 American individuals was examined to assess the accuracy and reliability of the three non-metric traits described by Phenice (1969) and revised by Klales et al. (2012) for assigning sex. In addition, the bilateral stability of the three non-metric traits was assessed to determine if asymmetrical expression of the traits compromises the classification accuracy of the revised method, since a prior study found that application of Phenice’s original technique yielded low classification accuracy when applied to the right innominate. Klales and colleagues claimed that expansion of the classification system from a dichotomous present/absent scale into five character states and the incorporation of logistic regression based on posterior probabilities vastly improves the accuracy rates for correct sex identification over the original method. Validity of the method developed by Klales and colleagues has not been tested by an external observer on a modern sample of American individuals (individuals who have died within the last 50 years). The current study tests the reliability and validity of Klales et al.’s (2012) technique for assigning sex of both the left and right innominate. Validity was tested using the sample of innominates 204 individuals from the William Bass Skeletal Collection housed at the University of Tennessee, Knoxville. Intra- and interobserver agreement was evaluated for Klales and colleagues’ method. Intra-observer and interobserver agreement was statistically evaluated with Cohen’s weighted kappa and the intra-class correlation coefficient. A series of Wilcoxon matched-pairs signed-ranks tests were used to evaluate statistical differences in the trait scores between the left and right innominates. Results show that the Klales et al. (2012) technique yields moderate to high levels of intra- and inter-observer agreement and yields correct sex identifications among individuals of known-sex in 93.6% of cases when all three traits are combined. Accuracy of correct sex identification was further increased to 99% by re-calibrating the logistical regression equation to fit the sample obtained from the William Bass Skeletal Collection. A Wilcoxon matched-pairs signed-ranks test revealed a statistically significant difference in trait scores of the ventral arc between European and African Americans; however, this difference does not compromise the accuracy of the method for correct identification of sex in known-sex individuals

Transmembrane Complexes of DAP12 Crystallized in Lipid Membranes Provide Insights into Control of Oligomerization in Immunoreceptor Assembly

The membrane-spanning α helices of single-pass receptors play crucial roles in stabilizing oligomeric structures and transducing biochemical signals across the membrane. Probing intermolecular transmembrane interactions in single-pass receptors presents unique challenges, reflected in a gross underrepresentation of their membrane-embedded domains in structural databases. Here, we present two high-resolution structures of transmembrane assemblies from a eukaryotic single-pass protein crystallized in a lipidic membrane environment. Trimeric and tetrameric structures of the immunoreceptor signaling module DAP12, determined to 1.77-Å and 2.14-Å resolution, respectively, are organized by the same polar surfaces that govern intramembrane assembly with client receptors. We demonstrate that, in addition to the well-studied dimeric form, these trimeric and tetrameric structures are made in cells, and their formation is competitive with receptor association in the ER. The polar transmembrane sequences therefore act as primary determinants of oligomerization specificity through interplay between charge shielding and sequestration of polar surfaces within helix interfaces

Conservatism and “copy-if-better” in chimpanzees (Pan troglodytes)

Social learning is predicted to evolve in socially living animals provided the learning process is not random but biased by certain socio-ecological factors. One bias of particular interest for the emergence of (cumulative) culture is the tendency to forgo personal behaviour in favour of relatively better variants observed in others, also known as the “copy-if-better” strategy. We investigated whether chimpanzees employ copy-if-better in a simple token-exchange paradigm controlling for individual and random social learning. After being trained on one token-type, subjects were confronted with a conspecific demonstrator who either received the same food reward as the subject (control condition) or a higher value food reward than the subject (test condition) for exchanging another token-type. In general, the chimpanzees persisted in exchanging the token-type they were trained on individually, indicating a form of conservatism consistent with previous studies. However, the chimpanzees were more inclined to copy the demonstrator in the test compared to the control condition, indicating a tendency to employ a copy-if-better strategy. We discuss the validity of our results by considering alternative explanations and relate our findings to the emergence of cumulative culture

Conservatism and “copy-if-better” in chimpanzees (Pan troglodytes)

This work was funded by the project SOMICS, ERC-Synergy grant # 609819 to Josep Call.Social learning is predicted to evolve in socially living animals provided the learning process is not random but biased by certain socio-ecological factors. One bias of particular interest for the emergence of (cumulative) culture is the tendency to forgo personal behaviour in favour of relatively better variants observed in others, also known as the "copy-if-better" strategy. We investigated whether chimpanzees employ copy-if-better in a simple token-exchange paradigm controlling for individual and random social learning. After being trained on one token-type, subjects were confronted with a conspecific demonstrator who either received the same food reward as the subject (control condition) or a higher value food reward than the subject (test condition) for exchanging another token-type. In general, the chimpanzees persisted in exchanging the token-type they were trained on individually, indicating a form of conservatism consistent with previous studies. However, the chimpanzees were more inclined to copy the demonstrator in the test compared to the control condition, indicating a tendency to employ a copy-if-better strategy. We discuss our findings in light of their relevance to the emergence of cumulative culture.Publisher PDFPeer reviewe

Chimpanzees do not take into account what others can hear in a competitive situation

Chimpanzees (Pan troglodytes) know what others can and cannot see in a competitive situation. Does this reflect a general understanding the perceptions of others? In a study by Hare et al. (2000) pairs of chimpanzees competed over two pieces of food. Subordinate individuals preferred to approach food that was behind a barrier that the dominant could not see, suggesting that chimpanzees can take the visual perspective of others. We extended this paradigm to the auditory modality to investigate whether chimpanzees are sensitive to whether a competitor can hear food rewards being hidden. Results suggested that the chimpanzees did not take what the competitor had heard into account, despite being able to locate the hiding place themselves by the noise