scholarly journals Sexual networks: measuring sexual selection in structured, polyandrous populations

2013 ◽  
Vol 368 (1613) ◽  
pp. 20120356 ◽  
Author(s):  
Grant C. McDonald ◽  
Richard James ◽  
Jens Krause ◽  
Tommaso Pizzari
Keyword(s):  
Sexual Selection ◽  
Temporal Structure ◽  
Natural Populations ◽  
Population Level ◽  
Global Scale ◽  
Local Scale ◽  
Emergent Property ◽  
Sexual Competition ◽  
Fine Grained ◽  
Multi Level

Sexual selection is traditionally measured at the population level, assuming that populations lack structure. However, increasing evidence undermines this approach, indicating that intrasexual competition in natural populations often displays complex patterns of spatial and temporal structure. This complexity is due in part to the degree and mechanisms of polyandry within a population, which can influence the intensity and scale of both pre- and post-copulatory sexual competition. Attempts to measure selection at the local and global scale have been made through multi-level selection approaches. However, definitions of local scale are often based on physical proximity, providing a rather coarse measure of local competition, particularly in polyandrous populations where the local scale of pre- and post-copulatory competition may differ drastically from each other. These limitations can be solved by social network analysis, which allows us to define a unique sexual environment for each member of a population: ‘local scale’ competition, therefore, becomes an emergent property of a sexual network. Here, we first propose a novel quantitative approach to measure pre- and post-copulatory sexual selection, which integrates multi-level selection with information on local scale competition derived as an emergent property of networks of sexual interactions. We then use simple simulations to illustrate the ways in which polyandry can impact estimates of sexual selection. We show that for intermediate levels of polyandry, the proposed network-based approach provides substantially more accurate measures of sexual selection than the more traditional population-level approach. We argue that the increasing availability of fine-grained behavioural datasets provides exciting new opportunities to develop network approaches to study sexual selection in complex societies.

Variation in flower biomass among nearby populations of Impatiens textori (Balsaminaceae): effects of population plant densities

2004 ◽  
Vol 82 (5) ◽  
pp. 563-572 ◽  
Author(s):  
Masakazu G Iwaizumi ◽  
Satoki Sakai
Keyword(s):  
Plant Density ◽  
Natural Populations ◽  
Population Level ◽  
Field Studies ◽  
Plant Size ◽  
Local Scale ◽  
Outcrossing Rate ◽  
Population Characteristics ◽  
Potted Plants ◽  
Plant Densities

Although most of the previously detected variation in flower biomass was among populations that were far apart from each other, differences in population characteristics (population size, area, and plant density) may bring the variation in flower biomass to a more local scale. To examine the variation in flower biomass among nearby populations of Impatiens textori Miq. (Balsaminaceae), field studies were conducted on six natural populations located along a stream in Japan. We also examined the dependence of flower biomass and outcrossing rate on population characteristics, as well as the differences in plant size and pollinator behavior among populations. We conducted pollination experiments with potted plants, in which plant density and flower size were independently manipulated. Mean flower mass varied among populations, being negatively dependent on plant density. One-factor ANCOVA showed that both plant size and the other population-level factor affected flower biomass variation. Experiments with potted plant arrays showed that geitonogamous pollination more likely occurred in sparse populations, but in field studies, the population outcrossing rate was not significantly dependent on plant density of the population. Thus, the variation in flower biomass cannot be fully explained by these commonly considered factors. Our results show that the flower biomass of populations may evolve locally in response to plant density or other population characteristics.Key words: variation, flower biomass, population, Impatiens textori, plant density, local scale.

Severe Maternal Morbidity: A Comparison of Definitions and Data Sources

2021 ◽  
Author(s):  
Jonathan M Snowden ◽  
Audrey Lyndon ◽  
Peiyi Kan ◽  
Alison El Ayadi ◽  
Elliott Main ◽  
...  
Keyword(s):  
Administrative Data ◽  
Maternal Morbidity ◽  
Claims Data ◽  
Birth Certificate ◽  
Population Level ◽  
Kappa Statistic ◽  
Data Sources ◽  
Severe Maternal Morbidity ◽  
Fine Grained ◽  
Control And Prevention

Abstract Severe maternal morbidity (SMM) is a composite outcome measure that indicates serious, potentially life-threatening maternal health problems. There is great interest in defining SMM using administrative data for surveillance and research. In the US, one common way of defining SMM at the population level is an index developed by the Centers for Disease Control and Prevention. Modifications have been proposed to this index (e.g., excluding maternal transfusion); some research defines SMM using an index introduced by Bateman et al. Birth certificate data are also increasingly being used to define SMM. We compared commonly used US definitions of SMM to each other among all California births, 2007-2012, using the Kappa statistic and other measures. We also evaluated agreement between maternal morbidity fields on the birth certificate compared to claims data. Concordance was generally low between the 7 definitions of SMM analyzed (i.e., κ < 0.4 for 13 of 21 two-way comparisons), Low concordance was particularly driven by presence/absence of transfusion and claims data versus birth certificate definitions. Low agreement between administrative data-based definitions of SMM highlights that results can be expected to differ between them. Further research is needed on validity of SMM definitions, using more fine-grained data sources.

scholarly journals Why is syphilis rising in Europe? Multi-level modelling of alternative hypotheses in 31 countries

2020 ◽  
Vol 30 (Supplement_5) ◽  
Author(s):  
A Mendez-Lopez ◽  
D Stuckler ◽  
T Noori ◽  
J C Semenza
Keyword(s):  
Risky Sexual Behavior ◽  
Population Level ◽  
Internet Survey ◽  
Probability Models ◽  
Syphilis Infection ◽  
Detection Rates ◽  
Substantial Impact ◽  
Multi Level ◽  
Sex With Men ◽  
Linear Probability

Abstract Background Syphilis transmission has increased markedly over the past two decades in Europe, concentrated in men who have sex with men. We test alternative potential social and behavioral individual- and population-level determinants of this resurgence. Methods Two rounds of the cross-sectional European Men who have sex with men Internet Survey (EMIS 2010 and 2017, n = 272,902) were used to fit multi-level linear probability models to evaluate determinants of the incidence of self-reported syphilis, capturing risky sexual behaviours and pre-exposure prophylaxis use, among others, adjusting for potential sociodemographic confounders. Results Self-reported syphilis incidence rates rose by about 1.8 percentage points (within the last 12 months) and 3.9 (within the last 5 years) between the 2010 and 2017 waves, after adjusting for sociodemographic factors. HIV status was a major risk factor for syphilis infection (27.6 ppt higher incident rate, 95%CI: 24.7 to 30.5). A dose-response relationship was observed between greater numbers of condomless non-steady partners and syphilis infection, with more than 10 partners estimating increases in the probability of diagnosis of over 25 ppt (11-20 partners vs none: 24.5 ppt, 95%CI: 20.5 to 28.5); further, we observed evidence of mediation for number of condomless non-steady partners, which attenuated the estimated rise in 2017 vs 2010 by about 35%. STI testing uptake also accounted for a substantial increase in syphilis incidence signaling higher detection rates over time. While country-level PrEP use was linked to greater number of condomless partners, there was no substantial impact of population-wide factors, including GDP and PrEP use, on overall syphilis trends. Conclusions Risky sexual behavior changes, particularly condomless sex with non-steady partners, appears to be a major contributing factor to rising syphilis incidence. Further research is needed to understand what accounts for this substantial behavior change. Key messages Increased number of condomless non-steady partners accounts for a substantial rise in syphilis trends. Population-level PrEP use was linked to increasing numbers of condomless non-steady partners but had no substantial impact on overall syphilis trends.

scholarly journals From Barriers to Enablers: The Role of Organizational Learning in Transitioning SMEs into the Circular Economy

2021 ◽  
Vol 13 (3) ◽  
pp. 1021
Author(s):  
Sara Scipioni ◽  
Meir Russ ◽  
Federico Niccolini
Keyword(s):  
Organizational Learning ◽  
Circular Economy ◽  
Business Models ◽  
Small And Medium Enterprises ◽  
Sustainable Business ◽  
Fine Grained ◽  
Contextual Elements ◽  
Transfer And Retention ◽  
Multi Level ◽  
Medium Enterprises

To contribute to small and medium enterprises’ (SMEs) sustainable transition into the circular economy, the study proposes the activation of organizational learning (OL) processes—denoted here as multi-level knowledge creation, transfer, and retention processes—as a key phase in introducing circular business models (CBMs) at SME and supply chain (SC) level. The research employs a mixed-method approach, using the focus group methodology to identify contextual elements impacting on CBM-related OL processes, and a survey-based evaluation to single out the most frequently used OL processes inside Italian construction SMEs. As a main result, a CBM-oriented OL multi-level model offers a fine-grained understanding of contextual elements acting mutually as barriers and drivers for OL processes, as possible OL dynamics among them. The multi-level culture construct—composed of external stakeholders’, SC stakeholders’, and organizational culture—identify the key element to activate CBM-oriented OL processes. Main implications are related to the identification of cultural, structural, regulatory, and process contextual elements across the external, SC, and organizational levels, and their interrelation with applicable intraorganizational and interorganizational learning processes. The proposed model would contribute to an improved implementation of transitioning into the circular economy utilizing sustainable business models in the construction SMEs.

scholarly journals Global‐ and Local‐Scale High‐Resolution Event Catalogs for Algorithm Testing

2019 ◽  
Author(s):  
Lisa Linville ◽  
Ronald Chip Brogan ◽  
Christopher Young ◽  
Katherine Anderson Aur
Keyword(s):  
Global Scale ◽  
Local Scale ◽  
Algorithm Performance ◽  
Directional Information ◽  
Event Sequences ◽  
University Of Utah ◽  
International Monitoring ◽  
Using Data ◽  
The University ◽  
Global And Local

ABSTRACT During the development of new seismic data processing methods, the verification of potential events and associated signals can present a nontrivial obstacle to the assessment of algorithm performance, especially as detection thresholds are lowered, resulting in the inclusion of significantly more anthropogenic signals. Here, we present two 14 day seismic event catalogs, a local‐scale catalog developed using data from the University of Utah Seismograph Stations network, and a global‐scale catalog developed using data from the International Monitoring System. Each catalog was built manually to comprehensively identify events from all sources that were locatable using phase arrival timing and directional information from seismic network stations, resulting in significant increases compared to existing catalogs. The new catalogs additionally contain challenging event sequences (prolific aftershocks and small events at the detection and location threshold) and novel event types and sources (e.g., infrasound only events and long‐wall mining events) that make them useful for algorithm testing and development, as well as valuable for the unique tectonic and anthropogenic event sequences they contain.

Networks of Photos, Landmarks, and People

Leonardo ◽  
2011 ◽  
Vol 44 (3) ◽  
pp. 240-243 ◽  
Author(s):  
David Crandall ◽  
Noah Snavely
Keyword(s):  
Recent Work ◽  
Human Behavior ◽  
Visual Representations ◽  
3D Models ◽  
Global Scale ◽  
Local Scale ◽  
Photo Sharing ◽  
The World ◽  
Vantage Points ◽  
Combining Information

Social photo-sharing sites like Flickr contain vast amounts of latent information about the world and human behavior. The authors describe their recent work in building automatic algorithms that analyze large collections of imagery in order to extract some of this information. At a global scale, geo-tagged photographs can be used to identify the most photographed places on Earth, as well as to infer the names and visual representations of these places. At a local scale, the authors build detailed 3D models of a scene by combining information from thousands of 2D photographs taken by different people and from different vantage points.

scholarly journals Evolutionary inference from QST-FST comparisons: disentangling local adaptation from altitudinal gradient selection in snapdragon plants

2018 ◽  
Author(s):  
Sara Marin ◽  
Juliette Archambeau ◽  
Vincent Bonhomme ◽  
Mylène Lascoste ◽  
Benoit Pujol
Keyword(s):  
Local Adaptation ◽  
Natural Populations ◽  
Common Garden ◽  
Global Scale ◽  
Structured Populations ◽  
Adaptive Divergence ◽  
Adaptation To Climate Change ◽  
Phenotypic Differentiation ◽  
Multiple Populations ◽  
Environmental Demand

ABSTRACTPhenotypic differentiation among natural populations can be explained by natural selection or by neutral processes such as drift. There are many examples in the literature where comparing the effects of these processes on multiple populations has allowed the detection of local adaptation. However, these studies rarely identify the agents of selection. Whether population adaptive divergence is caused by local features of the environment, or by the environmental demand emerging at a more global scale, for example along altitudinal gradients, is a question that remains poorly investigated. Here, we measured neutral genetic (FST) and quantitative genetic (QST) differentiation among 13 populations of snapdragon plants (Antirrhinum majus) in a common garden experiment. We found low but significant genetic differentiation at putatively neutral markers, which supports the hypothesis of either ongoing pervasive homogenisation via gene flow between diverged populations or reproductive isolation between disconnected populations. Our results also support the hypothesis of local adaptation involving phenological, morphological, reproductive and functional traits. They also showed that phenotypic differentiation increased with altitude for traits reflecting the reproduction and the phenology of plants, thereby confirming the role of such traits in their adaptation to environmental differences associated with altitude. Our approach allowed us to identify candidate traits for the adaptation to climate change in snapdragon plants. Our findings imply that environmental conditions changing with altitude, such as the climatic envelope, influenced the adaptation of multiple populations of snapdragon plants on the top of their adaptation to local environmental features. They also have implications for the study of adaptive evolution in structured populations because they highlight the need to disentangle the adaptation of plant populations to climate envelopes and altitude from the confounding effects of selective pressures acting specifically at the local scale of a population.

scholarly journals Perspectives from animal demography on incorporating evolutionary mechanism into plant population dynamics

2018 ◽  
Author(s):  
Maria Paniw
Keyword(s):  
Environmental Change ◽  
Evolutionary Dynamics ◽  
Natural Populations ◽  
Population Level ◽  
Plant Population ◽  
Future Research ◽  
Phenotypic Traits ◽  
Plant Population Dynamics ◽  
Future Research Agenda ◽  
Powerful Approach

AbstractWith a growing number of long-term, individual-based data on natural populations available, it has become increasingly evident that environmental change affects populations through complex, simultaneously occurring demographic and evolutionary processes. Analyses of population-level responses to environmental change must therefore integrate demography and evolution into one coherent framework. Integral projection models (IPMs), which can relate genetic and phenotypic traits to demographic and population-level processes, offer a powerful approach for such integration. However, a rather artificial divide exists in how plant and animal population ecologists use IPMs. Here, I argue for the integration of the two sub-disciplines, particularly focusing on how plant ecologists can diversify their toolset to investigate selection pressures and eco-evolutionary dynamics in plant population models. I provide an overview of approaches that have applied IPMs for eco-evolutionary studies and discuss a potential future research agenda for plant population ecologists. Given an impending extinction crisis, a holistic look at the interacting processes mediating population persistence under environmental change is urgently needed.

scholarly journals Comparative analysis of the ftness of Drosophila virilis lines contrasting in response to stress

2019 ◽  
Vol 22 (8) ◽  
pp. 1090-1096
Author(s):  
E. K. Karpova ◽  
I. Yu. Rauschenbach ◽  
N. E. Gruntenko
Keyword(s):  
Heat Stress ◽  
Natural Populations ◽  
Population Level ◽  
Stress Reaction ◽  
Egg Laying ◽  
Drosophila Virilis ◽  
Gonadotropic Hormone ◽  
Adverse Conditions ◽  
Low Intensity ◽  
Response To Stress

One of the crucial elements contributing to the adaptation of organisms to unfavorable environmental conditions is the reaction of stress. The study of its genetic control and role in adaptation to unfavorable conditions are of special interest. The juvenile hormone (JH) acts as a gonadotropic hormone in adult insects controlling the development of the ovaries, inducing vitellogenesis and oviposition. It was shown that a decrease in JH degradation in individuals reacting to adverse conditions by stress reaction (R­individuals) causes delay in egg laying and seems to allow the population to “wait out” the unfavorable conditions, thereby contributing to the adaptation at the population level. However, monitoring natural populations of D. melanogaster for the capability of stress reaction demonstrated that they have a high percentage of individuals incapable of it (NR­individuals). The study of reproductive characteristics of R­ and NR­individuals showed that under normal conditions R­individuals have the advantage of procreating offspring. Under unfavorable conditions, if the stressor is intense enough, NR­individuals die, but if its intensity is low, then they, unlike R­individuals, continue to produce offspring. Based on these data, it was hypothesized that the balance of R­ and NR­alleles in the population ensures its adaptation under frequent stresses of low intensity. To verify the hypothesis by an experiment, the ftness characteristics (lifespan, fecundity) of the R and NR lines of D. virilis were studied under normal conditions and under regular heat stress of various frequency.

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