The Value of Information for Populations in Varying Environments

The notion of information pervades informal descriptions of biological systems, but formal treatments face the problem of defining a quantitative measure of information rooted in a concept of fitness, which is itself an elusive notion. Here, we present a model of population dynamics where this problem is amenable to a mathematical analysis. In the limit where any information about future environmental variations is common to the members of the population, our model is equivalent to known models of financial investment. In this case, the population can be interpreted as a portfolio of financial assets and previous analyses have shown that a key quantity of Shannon's communication theory, the mutual information, sets a fundamental limit on the value of information. We show that this bound can be violated when accounting for features that are irrelevant in finance but inherent to biological systems, such as the stochasticity present at the individual level. This leads us to generalize the measures of uncertainty and information usually encountered in information theory

Positive selection in AvrP4 avirulence gene homologues across the genus Melampsora

Pathogen genes involved in interactions with their plant hosts are expected to evolve under positive Darwinian selection or balancing selection. In this study a single copy avirulence gene, AvrP4, in the plant pathogen Melampsora lini, was used to investigate the evolution of such a gene across species. Partial translation elongation factor 1-alpha sequences were obtained to establish phylogenetic relationships among the Melampsora species. We amplified AvrP4 homologues from species pathogenic on hosts from different plant families and orders, across the inferred phylogeny. Translations of the AvrP4 sequences revealed a predicted signal peptide and towards the C-terminus of the protein, six identically spaced cysteines were identified in all sequences. Maximum likelihood analysis of synonymous versus non-synonymous substitution rates indicated that positive selection played a role in the evolution of the gene during the diversification of the genus. Fourteen codons under significant positive selection reside in the C-terminal 28 amino acid region, suggesting that this region interacts with host molecules in most sequenced accessions. Selection pressures on the gene may be either due to the pathogenicity or avirulence function of the gene or both

The Effects of Task Difficulty and Conversational Cueing on Answer Formatting Problems in Surveys

A new and updated definitive resource for survey questionnaire testing and evaluation Building on the success of the first Questionnaire Development, Evaluation, and Testing (QDET) conference in 2002, this book brings together leading papers from the Second International Conference on Questionnaire Design, Development, Evaluation, and Testing (QDET2) held in 2016. The volume assesses the current state of the art and science of QDET; examines the importance of methodological attention to the questionnaire in the present world of information collection; and ponders how the QDET field can anticipate new trends and directions as information needs and data collection methods continue to evolve. Featuring contributions from international experts in survey methodology, Advances in Questionnaire Design, Development, Evaluation and Testing includes latest insights on question characteristics, usability testing, web probing, and other pretesting approaches, as well as: Recent developments in the design and evaluation of digital and self-administered surveys Strategies for comparing and combining questionnaire evaluation methods Approaches for cross-cultural and cross-national questionnaire development New data sources and methodological innovations during the last 15 years Case studies and practical applications Advances in Questionnaire Design, Development, Evaluation and Testing serves as a forum to prepare researchers to meet the next generation of challenges, making it an excellent resource for researchers and practitioners in government, academia, and the private sector

The Effects of Task Difficulty and Conversational Cueing on Answer Formatting Problems in Surveys

A new and updated definitive resource for survey questionnaire testing and evaluation Building on the success of the first Questionnaire Development, Evaluation, and Testing (QDET) conference in 2002, this book brings together leading papers from the Second International Conference on Questionnaire Design, Development, Evaluation, and Testing (QDET2) held in 2016. The volume assesses the current state of the art and science of QDET; examines the importance of methodological attention to the questionnaire in the present world of information collection; and ponders how the QDET field can anticipate new trends and directions as information needs and data collection methods continue to evolve. Featuring contributions from international experts in survey methodology, Advances in Questionnaire Design, Development, Evaluation and Testing includes latest insights on question characteristics, usability testing, web probing, and other pretesting approaches, as well as: Recent developments in the design and evaluation of digital and self-administered surveys Strategies for comparing and combining questionnaire evaluation methods Approaches for cross-cultural and cross-national questionnaire development New data sources and methodological innovations during the last 15 years Case studies and practical applications Advances in Questionnaire Design, Development, Evaluation and Testing serves as a forum to prepare researchers to meet the next generation of challenges, making it an excellent resource for researchers and practitioners in government, academia, and the private sector