Population size predicts lexical diversity, but so does the mean sea level - why it is important to correctly account for the structure of temporal data

In order to demonstrate why it is important to correctly account for the (serial dependent) structure of temporal data, we document an apparently spectacular relationship between population size and lexical diversity: for five out of seven investigated languages, there is a strong relationship between population size and lexical diversity of the primary language in this country. We show that this relationship is the result of a misspecified model that does not consider the temporal aspect of the data by presenting a similar but nonsensical relationship between the global annual mean sea level and lexical diversity. Given the fact that in the recent past, several studies were published that present surprising links between different economic, cultural, political and (socio-)demographical variables on the one hand and cultural or linguistic characteristics on the other hand, but seem to suffer from exactly this problem, we explain the cause of the misspecification and show that it has profound consequences. We demonstrate how simple transformation of the time series can often solve problems of this type and argue that the evaluation of the plausibility of a relationship is important in this context. We hope that our paper will help both researchers and reviewers to understand why it is important to use special models for the analysis of data with a natural temporal ordering

Comparative Dating Of Attine Ant And Lepiotaceous Cultivar Phylogenies Reveals Coevolutionary Synchrony And Discord

The mutualistic symbiosis between fungus-gardening ants and their cultivars has made fundamental contributions to our understanding of the coevolution of complex species interactions. Reciprocal specialization and vertical symbiont cotransmission are thought to promote a pattern of largely synchronous coevolutionary diversification in attines. Here we test this hypothesis by inferring the first time-calibrated multigene phylogeny of the lepiotaceous attine cultivars and comparing it with the recently published fossil-anchored phylogeny of the attine ants. While this comparison reveals some possible cases of synchronous origins of ant and fungal clades, there were a number of surprising asynchronies. For example, leaf-cutter cultivars appear to be significantly younger than the corresponding ant genera. Similarly, a clade of fungi interacting with primitive fungus-gardening ants-thought to be ancestral to the more derived leaf-cutter symbionts-appears instead to be a more recent acquisition from free-living stock. These macroevolutionary patterns are consistent with recent population-level studies suggesting occasional acquisition of novel cultivar types from environmental sources and horizontal transmission of cultivars between different ant species. Horizontal transmission events, even if rare, appear to form loose ecological connections between diffusely coevolving ant and fungus lineages that permit punctuated changes in the topology of the mutualistic ant-fungus interaction network.Integrative Biolog

Opinion Leaders as Brand Advocates in the Medical Industry – How Medical Professionals Perceive Source Credibility and Company Affiliations

Opinion leaders are experts in their domain of interest that share their experience with others. Opinion seekers, on the other hand, value the opinion leader’s knowledge and use them as a source of information to form an opinion about a service or a product. Marketers in the healthcare industry have recognized this information flow and have begun to use leading experts as a valuable third party who can take over the role of brand advocates or endorsers of a particular product. This research examines the marketing concept of opinion leaders advocating a product and persuading medical professionals. In two experimental studies, the influence of opinion leaders on medical students and practicing physicians and their perceived credibility of the message, as well as their attitude towards the company, is examined. The second focus of this research is how medical professionals cope with this form of persuasion attempt and whether their persuasion knowledge is activated. The influence on medical students and physicians through a peer expert - a skilled expert without any public recognition – represents the point of comparison in both studies. The results demonstrate that there are no significant differences in terms of perceived credibility between peer experts and opinion leaders, and that there are no differences regarding their influence on message credibility or attitude toward the company either. Moreover, disclosing company affiliations lead to the correction of attitudes toward the company. However, disclosing conflicts of interest can also be beneficial as it boosts the credibility of the source and helps to increase the perceived credibility of the corporation