scholarly journals Fast and strong amplifiers of natural selection

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Josef Tkadlec ◽  
Andreas Pavlogiannis ◽  
Krishnendu Chatterjee ◽  
Martin A. Nowak
Keyword(s):  
Evolutionary Process ◽  
Fixation Probability ◽  
Beneficial Mutation ◽  
Novel Mutations ◽  
Random Drift ◽  
The Past ◽  
Population Structures ◽  
Mixed Populations ◽  
Precise Relationship ◽  
The Cost

AbstractSelection and random drift determine the probability that novel mutations fixate in a population. Population structure is known to affect the dynamics of the evolutionary process. Amplifiers of selection are population structures that increase the fixation probability of beneficial mutants compared to well-mixed populations. Over the past 15 years, extensive research has produced remarkable structures called strong amplifiers which guarantee that every beneficial mutation fixates with high probability. But strong amplification has come at the cost of considerably delaying the fixation event, which can slow down the overall rate of evolution. However, the precise relationship between fixation probability and time has remained elusive. Here we characterize the slowdown effect of strong amplification. First, we prove that all strong amplifiers must delay the fixation event at least to some extent. Second, we construct strong amplifiers that delay the fixation event only marginally as compared to the well-mixed populations. Our results thus establish a tight relationship between fixation probability and time: Strong amplification always comes at a cost of a slowdown, but more than a marginal slowdown is not needed.

scholarly journals The effect of population structure on the rate of evolution

2013 ◽  
Vol 280 (1762) ◽  
pp. 20130211 ◽  
Author(s):  
Marcus Frean ◽  
Paul B. Rainey ◽  
Arne Traulsen
Keyword(s):  
Population Structure ◽  
Evolutionary Process ◽  
Ecological Factors ◽  
Structured Populations ◽  
Fixation Time ◽  
Fixation Probability ◽  
Star Graphs ◽  
Rate Of Evolution ◽  
Population Structures ◽  
Evolution Proceeds

Ecological factors exert a range of effects on the dynamics of the evolutionary process. A particularly marked effect comes from population structure, which can affect the probability that new mutations reach fixation. Our interest is in population structures, such as those depicted by ‘star graphs’, that amplify the effects of selection by further increasing the fixation probability of advantageous mutants and decreasing the fixation probability of disadvantageous mutants. The fact that star graphs increase the fixation probability of beneficial mutations has lead to the conclusion that evolution proceeds more rapidly in star-structured populations, compared with mixed (unstructured) populations. Here, we show that the effects of population structure on the rate of evolution are more complex and subtle than previously recognized and draw attention to the importance of fixation time. By comparing population structures that amplify selection with other population structures, both analytically and numerically, we show that evolution can slow down substantially even in populations where selection is amplified.

Measuring the cost of environmental compliance for Waikato dairy farmers - a survey approach

2015 ◽  
Vol 77 ◽  
pp. 159-166
Author(s):  
T.O.R. Macdonald ◽  
J.S. Rowarth ◽  
F.G. Scrimgeour
Keyword(s):  
Qualitative Data ◽  
Management Practice ◽  
Dairy Farm ◽  
Environmental Compliance ◽  
Dairy Farmers ◽  
The Past ◽  
Farm Systems ◽  
The Cost ◽  
Farm System ◽  
Survey Approach

The link between dairy farm systems and cost of environmental compliance is not always clear. A survey of Waikato dairy farmers was conducted to establish the real (non-modelled) cost of compliance with environmental regulation in the region. Quantitative and qualitative data were gathered to improve understanding of compliance costs and implementation issues for a range of Waikato farm systems. The average oneoff capital cost of compliance determined through a survey approach was $1.02 per kg milksolids, $1490 per hectare and $403 per cow. Costs experienced by Waikato farmers have exceeded average economic farm surplus for the region in the past 5 years. As regulation increases there are efficiencies to be gained through implementing farm infrastructure and farm management practice to best match farm system intensity. Keywords: Dairy, compliance, farm systems, nitrogen, Waikato

Attraction of prey

2018 ◽  
Author(s):  
John D. Horner ◽  
Bartosz J. Płachno ◽  
Ulrike Bauer ◽  
Bruno Di Giusto
Keyword(s):  
Visual Cues ◽  
Synergistic Action ◽  
Carnivorous Plants ◽  
Future Research ◽  
Acoustic Cues ◽  
Qualitative And Quantitative Analysis ◽  
Qualitative And Quantitative ◽  
The Past ◽  
The Cost ◽  
Prey Attraction

The ability to attract prey has long been considered a universal trait of carnivorous plants. We review studies from the past 25 years that have investigated the mechanisms by which carnivorous plants attract prey to their traps. Potential attractants include nectar, visual, olfactory, and acoustic cues. Each of these has been well documented to be effective in various species, but prey attraction is not ubiquitous among carnivorous plants. Directions for future research, especially in native habitats in the field, include: the qualitative and quantitative analysis of visual cues, volatiles, and nectar; temporal changes in attractants; synergistic action of combinations of attractants; the cost of attractants; and responses to putative attractants in electroantennograms and insect behavioral tests.

scholarly journals Hand Surgery in Saudi Arabia

2020 ◽  
Author(s):  
Abdullah E. Kattan ◽  
Mohammad M. Al-Qattan
Keyword(s):  
Saudi Arabia ◽  
Orthopedic Surgery ◽  
Significant Contribution ◽  
Hand Surgery ◽  
Fellowship Program ◽  
Novel Mutations ◽  
Work Related ◽  
The Past ◽  
Aesthetic Results ◽  
Hand Defects

AbstractHand surgery is a unique field that incorporates multiple specialties, aiming to provide the patient with a best possible functional and aesthetic results. Hand surgeons deal with different pathologies that require skills in several aspects of surgery. The field of hand surgery has evolved significantly over the past decades across the globe. This specialty has also been evolving in Saudi Arabia over the past 25 years. Some of the services offered to patients include specialized centers for brachial plexus, peripheral nerve, and pediatric hand surgery as well as centers for work-related hand injuries. There has also been significant contribution to the hand surgery literature from the hand surgeons working in Saudi Arabia, with hundreds of papers published in journals pertaining to hand surgery, orthopedic surgery, and plastic surgery, as well as the publication of several novel mutations causing congenital hand defects in journals concerned with genetics. The recent approval of a hand and microsurgery fellowship program in Saudi Arabia will also help boost this field in the country and the region.

Are Apprenticeships Still Relevant in the 21st Century? A Case Study of Changing Youth Training Arrangements in German Banks

ILR Review ◽  
2002 ◽  
Vol 55 (4) ◽  
pp. 667-685 ◽  
Author(s):  
David Finegold ◽  
Karin Wagner
Keyword(s):  
21St Century ◽  
Cost Savings ◽  
New Firms ◽  
Workplace Flexibility ◽  
Transferable Skills ◽  
The Past ◽  
Detailed Case ◽  
The Cost ◽  
Youth Training

The authors present a detailed case study of the evolution of apprenticeships in German banking over the past two decades to analyze why employers continue to be willing to invest in these programs that provide workers with transferable skills. They explain employers' motivation in terms of two “logics.” Some considerations stemming from the logic of consequences, such as recruitment cost savings and enhanced workplace flexibility, encourage retention of the apprenticeship system. On balance, however, the cost calculus that is at the heart of the logic of consequences would, if unopposed, encourage head-hunting for apprentices trained by other firms, eventually undermining the system. The countervailing logic of appropriateness, however, discourages defections from the system by fostering trust among employers, encouraging new firms to participate in the system, supporting the strong reputational effect associated with training, and creating mechanisms with which banks can have a hand in keeping the system efficient.

Acute Medicine Trainee Update

2011 ◽  
Vol 10 (3) ◽  
pp. 149-149
Author(s):  
Amy Daniel ◽  
◽  
Alice Miller ◽  
Keyword(s):  
Palliative Care ◽  
Medical Ethics ◽  
Advisory Committee ◽  
Skill Training ◽  
Skills Training ◽  
Training Programme ◽  
Acute Medicine ◽  
The Past ◽  
Training Programme Director ◽  
The Cost

We have been aware for a while that there are disparities in specialist skill provision both between and within deaneries – and the SAC is working hard to identify problems in this area. More recently, the issue of funding for specialist skills has been raised. It seems that some deaneries are happy and able to contribute towards the cost of training in a particular skill, while others are not; in at least one deanery, part-funding has now been withdrawn, leaving trainees to cover the entire cost of their chosen skills training. As specialist skill training is now a mandatory part of the Acute Medicine curriculum, we need to find a way to eliminate disparity both between different deaneries and between different skills. However, there is no easy solution, and for the time being, trainees will have to factor in the potential financial implications of a particular skill when they are considering their options. On a brighter note, the list of recognised specialist skills has increased over the past year. Palliative Care has been authorised as a suitable skill, and Medical Ethics and Law will soon also be added to the list. If you would like to propose a skill that is not currently listed in the Acute Medicine curriculum, you should discuss it with your training programme director, who can bring the proposal to the Acute Medicine Specialty Advisory Committee (SAC).

Estimating the cost of pure cybercrime to Australian individuals

2021 ◽  
Author(s):  
Coen Teunissen ◽  
Isabella Voce
Keyword(s):  
Economic Impact ◽  
The Other ◽  
Population Estimates ◽  
Australian Population ◽  
Probability Sampling ◽  
The Past ◽  
Online Panels ◽  
The Cost

This report estimates the cost of pure cybercrime to individuals in Australia in 2019. A survey was administered to a sample of 11,840 adults drawn from two online panels—one using probability sampling and the other non-probability sampling—with the resulting data weighted to better reflect the distribution of the wider Australian population. Thirty-four percent of respondents had experienced some form of pure cybercrime, with 14 percent being victimised in the last 12 months. This is equivalent to nearly 6.7 million Australian adults having ever been the victim of pure cybercrime, and 2.8 million Australians being victimised in the past year. Drawing on these population estimates, the total economic impact of pure cybercrime in 2019 was approximately $3.5b. This encompasses $1.9b in money directly lost by victims, $597m spent dealing with the consequences of victimisation, and $1.4b spent on prevention costs. Victims recovered $389m.

scholarly journals How culture and biology interact to shape language and the language faculty

2018 ◽  
Author(s):  
Kenny Smith
Keyword(s):  
Language Learning ◽  
Cultural Evolution ◽  
Cognitive Biases ◽  
Biological Evolution ◽  
Evolutionary Process ◽  
Evolutionary Models ◽  
Language Faculty ◽  
Repeated Cycle ◽  
Individual Level ◽  
Precise Relationship

Recent work suggests that linguistic structure develops through cultural evolution, as a consequence of the repeated cycle of learning and use by which languages persist. This work has important implications for our understanding of the evolution of the cognitive basis for language: in particular, human language and the cognitive capacities underpinning it are likely to have been shaped by co-evolutionary processes, where the cultural evolution of linguistic systems is shaped by and in turn shapes the biological evolution of the capacities underpinning language learning. I review several models of this co-evolutionary process, which suggest that the precise relationship between evolved biases in individuals and the structure of linguistic systems depends on the extent to which cultural evolution masks or unmasks individual-level cognitive biases from selection. I finish by discussing how these co-evolutionary models might be extended to cases where the biases involved in learning are themselves shaped by experience, as is the case for language.

scholarly journals The Perceptual and Cognitive Processes That Govern Egg Rejection in Hosts of Avian Brood Parasites

2021 ◽  
Vol 9 ◽  
Author(s):  
Daniel Hanley ◽  
Samantha L. Rutledge ◽  
Juliana Villa
Keyword(s):  
Cognitive Processing ◽  
Cognitive Processes ◽  
Selective Pressure ◽  
Null Model ◽  
Egg Rejection ◽  
Egg Recognition ◽  
Brood Parasites ◽  
The Past ◽  
The Cost ◽  
Receptor Noise

Hosts of avian brood parasites are under intense selective pressure to prevent or reduce the cost of parasitism. Many have evolved refined egg discrimination abilities, which can select for eggshell mimicry in their parasite. A classic assumption underlying these coevolutionary dynamics is that host egg recognition depends on the perceivable difference between their own eggs and those of their parasite. Over the past two decades, the receptor noise-limited (RNL) model has contributed to our understanding of these coevolutionary interactions by providing researchers a method to predict a host’s ability to discriminate a parasite’s egg from its own. Recent research has shown that some hosts are more likely to reject brown eggs than blue eggs, regardless of the perceived differences to their own. Such responses suggest that host egg recognition may be due to perceptual or cognitive processes not currently predictable by the RNL model. In this perspective, we discuss the potential value of using the RNL model as a null model to explore alternative perceptual processes and higher-order cognitive processes that could explain how and why some hosts make seemingly counter-intuitive decisions. Further, we outline experiments that should be fruitful for determining the perceptual and cognitive processing used by hosts for egg recognition tasks.

scholarly journals SURVEY TECHNIQUES/PROCEDURES AND DATA PROCESSING FOR MONITORING NEARSHORE SEDIMENT TRANSPORT

1982 ◽  
Vol 1 (18) ◽  
pp. 97
Author(s):  
J. Zacks
Keyword(s):  
Sediment Transport ◽  
Surf Zone ◽  
Survey Techniques ◽  
The Past ◽  
Bed Elevation ◽  
Innovative Methods ◽  
Survey Error ◽  
Nearshore Sediment Transport ◽  
The Many ◽  
The Cost

The cost of many coastal projects is often increased by the expensive beach repair and maintenance required to remedy the destabilising effects of structures on the adjoining coastline. Physical and/or mathematical models have been developed for use in planning these projects in order to predict and quantify the effects of marine sediment transport on the coastal topography. Such models need to be calibrated against prototype data and one method of gauging volumetric sediment movement is by successive bathymetric/ topographic profiting surveys which are performed seasonally and annually. Since large quantities of sediment are related to small changes in bed elevation it is clear that this profiling needs to be done with the utmost precision* The areas most affected extend from the beach through the surf zone to water depths of about 25 metres. The surf zone in particular is a dynamic and hostile area which falls outside the traditional activities of both the hydrographic and land surveyors. Consequently innovative methods, deficient in sound survey principle and practice, have often been pursued in this area without any attempt being made to assess the tolerance on the data. This paper attempts to show that it is possible to produce reliable and verifiable results to the required accuracy by using conventional survey equipment and techniques, also by taking the necessary precautions against the many possible sources of survey error. The procedures and techniques described have evolved from NRIO's involvement over the past decade in major projects at Richards Bay, Durban, Koeberg and in False Bay. The results of a recent verification investigation are fully reported in this paper.

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