Search results for " Populations"

A Simple Noise Model with Memory for Biological Systems

2005

A noise source model, consisting of a pulse sequence at random times with memory, is presented. By varying the memory we can obtain variable randomness of the stochastic process. The delay time between pulses, i. e. the noise memory, produces different kinds of correlated noise ranging from white noise, without delay, to quasi-periodical process, with delay close to the average period of the pulses. The spectral density is calculated. This type of noise could be useful to describe physical and biological systems where some delay is present. In particular it could be useful in population dynamics. A simple dynamical model for epidemiological infection with this noise source is presented. We …

Bandes enherbées, biodiversité mais sans danger

2011

National audience

Gene flow in the European coal tit, Periparus ater (Aves: Passeriformes): Low among Mediterranean populations but high in a continental contact zone

2018

Abstract Extant phylogeographical patterns of Palearctic terrestrial vertebrates are generally believed to have originated from glacial range fragmentation. Post-Pleistocene range expansions have led to the formation of secondary contact zones among genetically distinct taxa. For coal tits (Periparus ater), such a contact zone has been localized in Germany. In this study, we quantified gene flow between Fennoscandian and southern European coal tits using a set of 13 microsatellite loci. STRUCTURE analysis revealed four genetic clusters, two occurring on Mediterranean islands. German populations were genetically admixed but introgression of southern alleles was evident for Fennoscandian popu…

A latent profile analysis of trait emotional intelligence to identify beneficial and risk profiles in well-being and job performance: a study among J…

2016

Trait emotional intelligence (EI) is a noteworthy psychological resource in nursing. However, its effects on well-being and job performance are inconsistent. Thus, we explored the latent beneficial and risk profiles of trait EI among 461 Japanese eldercare nurses. Latent profile analysis revealed six latent profiles. In addition, multivariate analysis of covariance (MANCOVA) showed that the profile with the highest overall scores on the trait EI dimensions was associated with the most beneficial outcomes (better well-being, higher job performance). In contrast, the profiles with lower overall scores on the trait EI dimensions showed negative outcomes. Moreover, a disproportional profile, ch…

Time evolution of non-lethal infectious diseases: a semi-continuous approach.

2005

A model describing the dynamics related to the spreading of non-lethal infectious diseases in a fixed-size population is proposed. The model consists of a non-linear delay-differential equation describing the time evolution of the increment in the number of infectious individuals and depends upon a limited number of parameters. Predictions are in good qualitative agreement with data on influenza.

Population cycles and outbreaks of small rodents: ten essential questions we still need to solve

2021

AbstractMost small rodent populations in the world have fascinating population dynamics. In the northern hemisphere, voles and lemmings tend to show population cycles with regular fluctuations in numbers. In the southern hemisphere, small rodents tend to have large amplitude outbreaks with less regular intervals. In the light of vast research and debate over almost a century, we here discuss the driving forces of these different rodent population dynamics. We highlight ten questions directly related to the various characteristics of relevant populations and ecosystems that still need to be answered. This overview is not intended as a complete list of questions but rather focuses on the most…

On the thermodynamic origin of metabolic scaling

2018

The origin and shape of metabolic scaling has been controversial since Kleiber found that basal metabolic rate of animals seemed to vary as a power law of their body mass with exponent 3/4, instead of 2/3, as a surface-to-volume argument predicts. The universality of exponent 3/4 -claimed in terms of the fractal properties of the nutrient network- has recently been challenged according to empirical evidence that observed a wealth of robust exponents deviating from 3/4. Here we present a conceptually simple thermodynamic framework, where the dependence of metabolic rate with body mass emerges from a trade-off between the energy dissipated as heat and the energy efficiently used by the organi…

Assessment of production and qualitative characteristics of different populations of Salvia sclarea L. found in Sicily (Italy)

2021

Salvia sclarea L. is an important industrial crop, valued for its herbal-aromatic properties and high quality essential oils, that is used in food, pharmaceuticals and cosmetics. In this study, carried out from 2009 to 2010, the morphological and production characteristics and essential oil content and composition of three Sicilian populations were studied. In particular, the composition of essential oils extracted from primary and secondary inflorescences using steam distillation was assessed. Morphological, production and qualitative data from the three populations were subjected to analysis of variance and cluster analysis. Regarding the quality of the oils, only the most prevalent compo…

Tourist Populations

2009

Aborted quantitative study in the French music industry: the changes of music labels facing streaming

2020

International audience; This paper shows a failed case study of the impact of streaming on labels’ life through the exploitation of three quantitative databases. Streaming is a major external change for the music consumption and music producers. As labels are dealing with both producers and consumers, they may have been hardly impacted by this change. Yet there was a need to identify the changes that streaming brought and its impact for the organizations that decided not to adopt it. The ecology of population framework and the death vs dynamism dyad was supposed to give a clear reading of this phenomenon. In order to identify labels that did not adopt streaming, three databases were tested,…