Search results for " selection"

Forceps size and immune function in the earwig Forficula auricularia L.

2007

Females of many species select their mates on the basis of the size or intensity of sexual ornaments, and it has been suggested that these provide reliable signals of a male’s ability to resist parasites and pathogens. European earwigs, Forficula auricularia, are sexually dimorphic in forceps shape and length. Male forceps are used as weapons in male contests for access to females, but recent findings suggest that females also choose males on the basis of their forceps length. In the present study, we tested the hypotheses that in the European earwig, F. auricularia, the size of forceps is correlated with immune function and that immune function differs between the sexes. We found that enca…

Quantification of sexual dimorphism in Asellus aquaticus (Crustacea: Isopoda) using outline approaches

2002

A marked sexual dimorphism is often observed in arthropods species in which males perform precopulatory mate guarding. It is generally thought to reflect the influence of sexual selection. Until now, sexual dimorphisms associated with mate guarding have mainly been qualitatively described. However, assessing the effects of sexual selection on sexual dimorphims requires a preliminary quantitative assessment of differences in morphology between sexes. Using Fourier analyses, we tested if morphological dimorphisms could be quantitatively assessed in the isopod Asellus aquaticus. In addition, we checked whether sexual dimorphism in shape was exclusively related to mate guarding through consider…

Sperm competition and small size advantage for males of the golden orb-web spider Nephila edulis

2000

Sexual selection, through female choice and/or male‐male competition, has influenced the nature and direction of sexual size dimorphism in numerous species. However, few studies have examined the influence of sperm competition on size dimorphism. The orb-web spider Nephila edulis has a polygamous mating system and extreme size dimorphism. Additionally, the frequency distribution of male body size is extremely skewed with most males being small and few large. The duration of copulation, male size and sexual cannibalism have been identified as the significant factors determining patterns of sperm precedence in spiders. In double mating trials, females were assigned to three treatments: either…

Evolutionary processes in the emergence and recent spread of the syphilis agent, Treponema pallidum

2022

Abstract The incidence of syphilis has risen worldwide in the last decade in spite of being an easily treated infection. The causative agent of this sexually transmitted disease is the bacterium Treponema pallidum subspecies pallidum (TPA), very closely related to subsp. pertenue (TPE) and endemicum (TEN), responsible for the human treponematoses yaws and bejel, respectively. Although much focus has been placed on the question of the spatial and temporary origins of TPA, the processes driving the evolution and epidemiological spread of TPA since its divergence from TPE and TEN are not well understood. Here, we investigate the effects of recombination and selection as forces of genetic diver…

Learning Automata Based Q-learning for Content Placement in Cooperative Caching

2019

An optimization problem of content placement in cooperative caching is formulated, with the aim of maximizing sum mean opinion score (MOS) of mobile users. Firstly, a supervised feed-forward back-propagation connectionist model based neural network (SFBC-NN) is invoked for user mobility and content popularity prediction. More particularly, practical data collected from GPS-tracker app on smartphones is tackled to test the accuracy of mobility prediction. Then, a learning automata-based Q-learning (LAQL) algorithm for cooperative caching is proposed, in which learning automata (LA) is invoked for Q-learning to obtain an optimal action selection in a random and stationary environment. It is p…

An Automatic System for the Analysis and Classification of Human Atrial Fibrillation Patterns from Intracardiac Electrograms

2008

This paper presents an automatic system for the analysis and classification of atrial fibrillation (AF) patterns from bipolar intracardiac signals. The system is made up of: 1) a feature- extraction module that defines and extracts a set of measures potentially useful for characterizing AF types on the basis of their degree of organization; 2) a feature-selection module (based on the Jeffries-Matusita distance and a branch and bound search algorithm) identifying the best subset of features for discriminating different AF types; and 3) a support vector machine technique-based classification module that automatically discriminates the AF types according to the Wells' criteria. The automatic s…

Honesty of agonistic signalling and effects of size and motivation asymmetry in contests

1999

Game theoretical models predict that the main function of fighting behaviour is to assess the relative fighting ability of opponents. The sequential assessment game has often been used to investigate contests, while honest signalling theory has received much less attention. With the wolf spider Hygrolycosa rubrofasciata we investigated whether male agonistic signalling can reveal honest information about fighting ability, and how size and motivation asymmetries affect male fighting behaviour. We also determined whether male–male competition affects the courtship behaviour of the males. We found that agonistic drumming activity is an honest indicator of male fighting ability, and that relati…

P-spline quantile regression: a new algorithm for smoothing parameter selection

Majority and minority influence, task representation and inductive reasoning

1996

One hundred and fifty-five participants had to solve a set of 2–4–6 like reasoning problems (Wason, 1960), in which they were told which hypothesis a majority (or a minority) proposed, as well as which example was used for the test. In a 2 × 2 design, participants were also told that the problems allowed either one single correct answer or several possible answers. Results show that, when the source is a majority and the problem allows one single answer, most participants adopt the source's hypothesis and use confirmatory testing. On the contrary, it is when the source is a minority and the problem allows several answers that most participants give alternative hypotheses and use disconfirma…

Narcissism and the Strategic Pursuit of Short-Term Mating:Universal Links across 11 World Regions of the International Sexuality Description Project-2

2017

Previous studies have documented links between sub-clinical narcissism and the active pursuit of short-term mating strategies (e.g., unrestricted sociosexuality, marital infidelity, mate poaching). Nearly all of these investigations have relied solely on samples from Western cultures. In the current study, responsesfrom a cross-cultural survey of 30,470 people across 53 nations spanning 11 world regions (North America, Central/South America, Northern Europe, Western Europe, Eastern Europe, Southern Europe, Middle East, Africa, Oceania, Southeast Asia, and East Asia) were used to evaluate whether narcissism (as measured by the Narcissistic Personality Inventory; NPI) was universally associat…