Search results for "Ion density"
showing 9 items of 229 documents
Rotifer vertical distributions in a meromictic basin of Lake Banyoles (Spain)
1993
The vertical distribution of rotifer populations has been analyzed in a meromictic basin (III) of the karstic Lake Banyoles. This basin had, at the time of the study, an anaerobic monimolimnion from around 17 m in summer or 21 in winter to 25 m, its maximum depth. However, below this layer a warmer micro aerophiliczone with suspended marls is found in a chimney to a depth of 130 m.
COMPUTER AIDED RESTORATION TOOLS TO ASSIST THE CONSERVATION OF AN ANCIENT SCULPTURE. THE COLOSSAL STATUE OF ZEUS ENTHRONED
2017
Abstract. The research focuses on the contribution of the integrated application of Computer Aided Restoration digital procedures as a means to guide the integration measure of an artifact, innovating and implementing the traditional investigation methods. The aim of the study was to provide effective geometrical-formal investigation tools in the frame of the conservation work of Zeus enthroned from Soluntum, conserved in the Archaeological Museum “A. Salinas” of Palermo. The paper describes the workflow of the 3D acquisition and graphical modeling with non-invasive digitalization and high information density techniques to assist the conservation of the legs of the throne, especially the in…
Marine reserves : fish life history and ecological traits matter
2010
Copyright by the Ecological Society of America
Effects of musicianship and experimental task on perceptual segmentation
2015
The perceptual structure of music is a fundamental issue in music psychology that can be systematically addressed via computational models. This study estimated the contribution of spectral, rhythmic and tonal descriptors for prediction of perceptual segmentation across stimuli. In a real-time task, 18 musicians and 18 non-musicians indicated perceived instants of significant change for six ongoing musical stimuli. In a second task, 18 musicians parsed the same stimuli using audio editing software to provide non-real-time segmentation annotations. We built computational models based on a non-linear fuzzy integration of basic and interaction descriptors of local musical novelty. We found tha…
Data from: Daphnia invest in sexual reproduction when its relative costs are reduced
2018
The timing of sex in facultatively sexual organisms is critical to fitness, due to the differing demographic consequences of sexual vs. asexual reproduction. In addition to the costs of sex itself, an association of sex with the production of dormant life stages also influences the optimal use of sex, especially in environments where resting eggs are essential to survive unfavourable conditions. Here we document population dynamics and the occurrence of sexual reproduction in natural populations of Daphnia magna across their growing season. The frequency of sexually reproducing females and males increased with population density and with decreasing asexual clutch sizes. The frequency of sex…
Data from: Daphnia females adjust sex allocation in response to current sex ratio and density
2019
Cyclical parthenogenesis presents an interesting challenge for the study of sex allocation, as individuals’ allocation decisions involve both the choice between sexual and asexual reproduction, and the choice between sons and daughters. Male production is therefore expected to depend on ecological and evolutionary drivers of overall investment in sex, and those influencing male reproductive value during sexual periods. We manipulated experimental populations, and made repeated observations of natural populations over their growing season, to disentangle effects of population density and the timing of sex from effects of adult sex ratio on sex allocation in cyclically parthenogenetic Daphnia…
Intergenerational fitness effects of the early life environment in a wild rodent
2019
The early life environment can have profound, long‐lasting effects on an individual's fitness. For example, early life quality might (a) positively associate with fitness (a silver spoon effect), (b) stimulate a predictive adaptive response (by adjusting the phenotype to the quality of the environment to maximize fitness) or (c) be obscured by subsequent plasticity. Potentially, the effects of the early life environment can persist beyond one generation, though the intergenerational plasticity on fitness traits of a subsequent generation is unclear. To study both intra‐ and intergenerational effects of the early life environment, we exposed a first generation of bank voles to two early life…
Early life of fathers affects offspring fitness in a wild rodent
2019
Intergenerational fitness effects on offspring due to the early life of the parent are well studied from the standpoint of the maternal environment, but intergenerational effects owing to the paternal early life environment are often overlooked. Nonetheless, recent laboratory studies in mammals and ecologically relevant studies in invertebrates predict that paternal effects can have a major impact on the offspring's phenotype. These non‐genetic, environment‐dependent paternal effects provide a mechanism for fathers to transmit environmental information to their offspring, and could allow rapid adaptation. We used the bank vole Myodes glareolus, a wild rodent species with no paternal care, t…
Phosphorus limitation enhances parasite impact: feedback effects at the population level
2014
Background Nutrient deficiency affects the growth and population dynamics of consumers. Endoparasites can be seen as consumers that drain carbon (C) or energy from their host while simultaneously competing for limiting resources such as phosphorus (P). Depending on the relative demands of the host and the parasite for the limiting nutrient, intensified resource competition under nutrient limitation can either reduce the parasite’s effect on the host or further reduce the fitness of the nutrient-limited host. So far, knowledge of how nutrient limitation affects parasite performance at the host population level and how this affects the host populations is limited. Results We followed the popu…