68 research outputs found

    How Humans Differ from Other Animals in Their Levels of Morphological Variation

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    Animal species come in many shapes and sizes, as do the individuals and populations that make up each species. To us, humans might seem to show particularly high levels of morphological variation, but perhaps this perception is simply based on enhanced recognition of individual conspecifics relative to individual heterospecifics. We here more objectively ask how humans compare to other animals in terms of body size variation. We quantitatively compare levels of variation in body length (height) and mass within and among 99 human populations and 848 animal populations (210 species). We find that humans show low levels of within-population body height variation in comparison to body length variation in other animals. Humans do not, however, show distinctive levels of within-population body mass variation, nor of among-population body height or mass variation. These results are consistent with the idea that natural and sexual selection have reduced human height variation within populations, while maintaining it among populations. We therefore hypothesize that humans have evolved on a rugged adaptive landscape with strong selection for body height optima that differ among locations

    Evolution of Assortative Mating in a Population Expressing Dominance

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    In this article, we study the influence of dominance on the evolution of assortative mating. We perform a population-genetic analysis of a two-locus two-allele model. We consider a quantitative trait that is under a mixture of frequency-independent stabilizing selection and density- and frequency-dependent selection caused by intraspecific competition for a continuum of resources. The trait is determined by a single (ecological) locus and expresses intermediate dominance. The second (modifier) locus determines the degree of assortative mating, which is expressed in females only. Assortative mating is based on similarities in the quantitative trait (‘magic trait’ model). Analytical conditions for the invasion of assortment modifiers are derived in the limit of weak selection and weak assortment. For the full model, extensive numerical iterations are performed to study the global dynamics. This allows us to gain a better understanding of the interaction of the different selective forces. Remarkably, depending on the size of modifier effects, dominance can have different effects on the evolution of assortment. We show that dominance hinders the evolution of assortment if modifier effects are small, but promotes it if modifier effects are large. These findings differ from those in previous work based on adaptive dynamics

    New regime of inverse saturable absorption for self-stabilizing passively mode-locked lasers

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    ISSN:0946-2171ISSN:1432-0649ISSN:0721-7269ISSN:0340-379

    The potential of knowing more: A review of data-driven urban water management

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    The promise of collecting and utilizing large amounts of data has never been greater in the history of urban water management (UWM). This paper reviews several data-driven approaches which play a key role in bringing forward a sea change. It critically investigates whether data-driven UWM offers a promising foundation for addressing current challenges and supporting fundamental changes in UWM. We discuss the examples of better rain-data management, urban pluvial flood-risk management and forecasting, drinking water and sewer network operation and management, integrated design and management, increasing water productivity, wastewater-based epidemiology and on-site water and wastewater treatment. The accumulated evidence from literature points toward a future UWM that offers significant potential benefits thanks to increased collection and utilization of data. The findings show that data-driven UWM allows us to develop and apply novel methods, to optimize the efficiency of the current networkbased approach, and to extend functionality of today’s systems. However, generic challenges related to data-driven approaches (e.g., data processing, data availability, data quality, data costs) and the specific challenges of data-driven UWM need to be addressed, namely data access and ownership, current engineering practices and the difficulty of assessing the cost benefits of data-driven UWM

    The potential of knowing more: A review of data-driven urban water management

    No full text
    The promise of collecting and utilizing large amounts of data has never been greater in the history of urban water management (UWM). This paper reviews several data-driven approaches which play a key role in bringing forward a sea change. It critically investigates whether data-driven UWM offers a promising foundation for addressing current challenges and supporting fundamental changes in UWM. We discuss the examples of better rain-data management, urban pluvial flood-risk management and forecasting, drinking water and sewer network operation and management, integrated design and management, increasing water productivity, wastewater-based epidemiology and on-site water and wastewater treatment. The accumulated evidence from literature points toward a future UWM that offers significant potential benefits thanks to increased collection and utilization of data. The findings show that data-driven UWM allows us to develop and apply novel methods, to optimize the efficiency of the current networkbased approach, and to extend functionality of today’s systems. However, generic challenges related to data-driven approaches (e.g., data processing, data availability, data quality, data costs) and the specific challenges of data-driven UWM need to be addressed, namely data access and ownership, current engineering practices and the difficulty of assessing the cost benefits of data-driven UWM

    Welcome to country: legal meanings and cultural implications

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    The act of acknowledging Country prior to public events has become commonplace in Australia. Indigenous language groups and tribal boundaries are named and an apparent recognition of traditional owners is voiced. Too often, however, the legal and political implications of the act of acknowledging Country are ignored. Furthermore, such an acknowledgment is rarely explored and deconstructed in order to understand its traditional cultural and normative significance. This paper is the result of an ongoing dialogue between an Aboriginal man from the Illawarra in New South Wales and a legal anthropologist from the other side of the planet. Throughout their conversation the two authors have explored their reciprocal perspectives on the recognition of Country in an attempt to develop a negotiated understanding. They have identified protocols and paradigms through which the act of acknowledging Country can be reciprocally construed and explained. They have also investigated its political and legal meanings and they have asked questions about its normative implications. Finally, they have attempted to identify a meaningful approach through which the act of acknowledging Country can be performed in a way that is respectful of its appropriate cultural, normative and legal significance

    Persistent variations in average height between countries and between socio-economic groups: an overview of 10 European countries.

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    PRIMARY OBJECTIVES: This paper aims to provide an overview of variations in average height between 10 European countries, and between socio-economic groups within these countries. DATA AND METHODS: Data on self-reported height of men and women aged 20-74 years were obtained from national health, level of living or multipurpose surveys for 1987-1994. Regression analyses were used to estimate height differences between educational groups and to evaluate whether the differences in average height between countries and between educational groups were smaller among younger than among older birth cohorts. RESULTS: Men and women were on average tallest in Norway, Sweden, Denmark and the Netherlands and shortest in France, Italy and Spain (range for men: 170-179 cm; range for women: 160-167 cm). The differences in average height between northern and southern European countries were not smaller among younger than among older birth cohorts. In most countries average height increased linearly with increasing birth-year (approximately 0.7-0.8 cm/5 years for men and approximately 0.4 cm/5 years for women). In all countries, lower educated men and women on average were shorter than higher educated men (range of differences: 1.6-3.0 cm) and women (range of differences: 1.2-2.2 cm). In most countries, education-related height differences were not smaller among younger than among older birth cohorts. CONCLUSIONS: The persistence of international differences in average height into the youngest birth cohorts indicates a high degree of continuity of differences between countries in childhood living conditions. Similarly, the persistence of education-related height differences indicates continuity of socio-economic differences in childhood living conditions, and also suggests that socio-economic differences in childhood living conditions will continue to contribute to socio-economic differences in health at adult ages. &nbsp
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