Why Mendelian segregation?

2006 ◽  
Vol 34 (4) ◽  
pp. 566-568 ◽  
Author(s):  
F. Úbeda
Keyword(s):  
Natural Selection ◽  
Segregation Distortion ◽  
New Paradigm ◽  
Mendelian Segregation ◽  
New Model ◽  
Unrealistic Assumption

The discovery of alleles that are able to distort segregation during meiosis in their favour raises the question of why Mendelian segregation is the rule and segregation distortion the exception. Previous research on this topic was limited by an unrealistic assumption: equal segregation in the two sexes. Úbeda and Haig [(2005) Genetics 170, 1345–1357] provide a new model allowing sex-specific segregation distortion. This model shows that natural selection favours departure from Mendelian expectations. The evolutionary instability of Mendelian segregation under more realistic assumptions requires a new paradigm that explains its ubiquity.

scholarly journals Excellence in medical training: developing talent—not sorting it

2021 ◽  
Author(s):  
Gurpreet Dhaliwal ◽  
Karen E. Hauer
Keyword(s):  
Medical Training ◽  
The United States ◽  
New Paradigm ◽  
New Model ◽  
Achievement Growth ◽  
Medical Licensing ◽  
Multiple Domains ◽  
Learning Schools ◽  
Teacher Excellence ◽  
Honor Society

AbstractMany medical schools have reconsidered or eliminated clerkship grades and honor society memberships. National testing organizations announced plans to eliminate numerical scoring for the United States Medical Licensing Examination Step 1 in favor of pass/fail results. These changes have led some faculty to wonder: “How will we recognize and reward excellence?” Excellence in undergraduate medical education has long been defined by high grades, top test scores, honor society memberships, and publication records. However, this model of learner excellence is misaligned with how students learn or what society values. This accolade-driven view of excellence is perpetuated by assessments that are based on gestalt impressions influenced by similarity between evaluators and students, and assessments that are often restricted to a limited number of traditional skill domains. To achieve a new model of learner excellence that values the trainee’s achievement, growth, and responsiveness to feedback across multiple domains, we must envision a new model of teacher excellence. Such teachers would have a growth mindset toward assessing competencies and learning new competencies. Actualizing true learner excellence will require teachers to change from evaluators who conduct assessments of learning to coaches who do assessment for learning. Schools will also need to establish policies and structures that foster a culture that supports this change. In this new paradigm, a teacher’s core duty is to develop talent rather than sort it.

A New Paradigm for Ship Design Calculations

2015 ◽  
Author(s):  
Stephen M. Hollister
Keyword(s):  
User Interface ◽  
Graphical User Interface ◽  
Ship Design ◽  
New Paradigm ◽  
New Model ◽  
Analysis Tools ◽  
Cross Platform ◽  
Open Code ◽  
Design Calculations ◽  
Interactive Graphical User Interface

A new model for ship design calculations is presented that separates the graphical user interface (GUI) from the calculations (CALC). Design programs can now be defined as more than one interactive graphical user interface tied to one calculation. Several different GUIs can be created for one CALC engine and one GUI can be created to launch several CALC engines in sequence. The GUI of choice is a spreadsheet due to its availability, programmable customization, powerful analysis tools, cross-platform capability, and open code environment.

scholarly journals Processing Information in the Clouds

Proceedings ◽  
2020 ◽  
Vol 47 (1) ◽  
pp. 25
Author(s):  
Mark Burgin ◽  
Eugene Eberbach ◽  
Rao Mikkilineni
Keyword(s):  
Artificial Intelligence ◽  
Cloud Computing ◽  
Human Brain ◽  
Incremental Learning ◽  
Computational Models ◽  
Higher Order ◽  
Turing Machines ◽  
New Paradigm ◽  
New Model ◽  
Processing Information

Cloud computing makes the necessary resources available to the appropriate computation to improve scaling, resiliency, and the efficiency of computations. This makes cloud computing a new paradigm for computation by upgrading its artificial intelligence (AI) to a higher order. To explore cloud computing using theoretical tools, we use cloud automata as a new model for computation. Higher-level AI requires infusing features of the human brain into AI systems such as incremental learning all the time. Consequently, we propose computational models that exhibit incremental learning without stopping (sentience). These features are inherent in reflexive Turing machines, inductive Turing machines, and limit Turing machines.

scholarly journals Pandemia COVID-19 i „nowa normalność” w systemie komunikowania. Wyzwania regulacyjne epoki cyfry

2021 ◽  
Vol 2021 (2 (11)) ◽  
pp. 9-21
Author(s):  
Alicja Jaskiernia ◽  
Keyword(s):  
Social Life ◽  
New Technologies ◽  
Social Costs ◽  
Research Center ◽  
New Paradigm ◽  
Think Tank ◽  
New Model ◽  
Internet Technologies ◽  
The Individual ◽  
Radical Transformation

The radical transformation of life on the planet caused by the COVID-19 pandemic has accelerated the convergence of social and private spaces by internet technologies. Big Tech companies have grown into key market and social life players. The article presents the key findings from the debate conducted by the American think-tank Pew Research Center in early 2021. The hypothesis concerns the necessity to adopt a new model of internet platforms accountabilities in the era of “dual convergence”, in the context of searching for a new paradigm of human-technology relations, more comprehensive reflecting the individual and social costs of using new technologies.

scholarly journals Standard codon substitution models overestimate purifying selection for non-stationary data

2016 ◽  
Author(s):  
Benjamin D Kaehler ◽  
Von Bing Yap ◽  
Gavin A Huttley
Keyword(s):  
Natural Selection ◽  
De Novo ◽  
Purifying Selection ◽  
Neutral Evolution ◽  
Protein Coding ◽  
Synonymous Substitutions ◽  
New Model ◽  
Sequence Composition ◽  
Codon Substitution ◽  
Substitution Models

Estimation of natural selection on protein-coding sequences is a key comparative genomics approach for de novo prediction of lineage specific adaptations. Selective pressure is measured on a per-gene basis by comparing the rate of non-synonymous substitutions to the rate of neutral evolution, typically assumed to be the rate of synonymous substitutions. All published codon substitution models have been time-reversible and thus assume that sequence composition does not change over time. We previously demonstrated that if time-reversible DNA substitution models are applied blindly in the presence of changing sequence composition, the number of substitutions is systematically biased towards overestimation. We extend these findings to the case of codon substitution models and further demonstrate that the ratio of non-synonymous to synonymous rates of substitution tends to be underestimated over three data sets of insects, mammals, and vertebrates. Our basis for comparison is a non-stationary codon substitution model that allows sequence composition to change. Model selection and model fit results demonstrate that our new model tends to fit the data better. Direct measurement of non-stationarity shows that bias in estimates of natural selection and genetic distance increases with the degree of violation of the stationarity assumption. Additionally, inferences drawn under time-reversible models are systematically affected by compositional divergence. As genomic sequences accumulate at an accelerating rate, the importance of accurate de novo estimation of natural selection increases. Our results establish that our new model provides a more robust perspective on this fundamental quantity.

scholarly journals metaVaR: introducing metavariant species models for reference-free metagenomic-based population genomics

2020 ◽  
Author(s):  
Romuald Laso-Jadart ◽  
Christophe Ambroise ◽  
Pierre Peterlongo ◽  
Mohammed-Amin Madoui
Keyword(s):  
Natural Selection ◽  
Reference Genome ◽  
Population Genomics ◽  
Variant Calling ◽  
Independent Set ◽  
Real Data ◽  
Metagenomic Data ◽  
Accurate Estimation ◽  
New Paradigm ◽  
Population Genomic

AbstractMotivationThe availability of large metagenomic data offers great opportunities for the population genomic analysis of uncultured organisms, especially for small eukaryotes that represent an important part of the unexplored biosphere while playing a key ecological role. However, the majority of these species lacks reference genome or transcriptome which constitutes a technical barrier for classical population genomic analyses.ResultsWe introduce the metavariant species (MVS) model, a representation of the species only by intra-species nucleotide polymorphism. We designed a method combining reference-free variant calling, multiple density-based clustering and maximum weighted independent set algorithms to cluster intra-species variant into MVS directly from multisample metagenomic raw reads without reference genome or reads assembly. The frequencies of the MVS variants are then used to compute population genomic statistics such as FST in order to estimate genomic differentiation between populations and to identify loci under natural selection. The MVSs construction was tested on simulated and real metagenomic data. MVs showed the required quality for robust population genomics and allowed an accurate estimation of genomic differentiation (ΔFST < 0.0001 and < 0.03 on simulated and real data respectively). Loci predicted under natural selection on real data were all found by MVSs. MVSs represent a new paradigm that may simplify and enhance holistic approaches for population genomics and evolution of microorganisms.AvailabilityThe method was implemented in a R package, metaVaR. https://github.com/madoui/[email protected]

scholarly journals About a New Model of Engineering Training

2019 ◽  
Vol 28 (7) ◽  
pp. 94-101 ◽  
Author(s):  
A. A. Sysoev ◽  
E. B. Vesna ◽  
Yu. I. Aleksandrov
Keyword(s):  
Engineering Education ◽  
Educational Process ◽  
Innovative Technology ◽  
Learning Technology ◽  
Engineering Process ◽  
New Paradigm ◽  
New Model ◽  
Proposed Model ◽  
Engineering Activity ◽  
Engineering Training

The aim of the article is to present a model of training engineers based on new approaches to engineering education, taking into account the modern achievements of psychology. The authors believe that the main reason for the insufficient level of engineering training is the discrepancy between the essence of the knowledge transferred to students (both form and content) to the specifics of engineering activity. Therefore, the most important task is to eliminate this contradiction. The basis of the proposed model of engineering training is the design of the educational process in the logic of engineering process in the development of innovative technology. This learning technology called “Simulation-Activity Technology of Engineering Training” (SATET) has been developed and tested at the National Research Nuclear University MEPhI in training engineersdevelopers of innovative technology. The foundations laid in the proposed technology of engineering training, and the mechanisms for its implementation can be considered as a start for the development of a new paradigm of training engineers. 

scholarly journals Mapping Quantitative Trait Loci Using Distorted Markers

2009 ◽  
Vol 2009 ◽  
pp. 1-11 ◽  
Author(s):  
Shizhong Xu ◽  
Zhiqiu Hu
Keyword(s):  
Qtl Mapping ◽  
Segregation Distortion ◽  
Quantitative Trait ◽  
Expectation Maximization Algorithm ◽  
Real Life ◽  
Segregation Ratio ◽  
Joint Analysis ◽  
Mendelian Segregation ◽  
Real Life Data ◽  
Trait Locus

Quantitative trait locus (QTL) mapping is usually performed using markers that follow a Mendelian segregation ratio. We developed a new method of QTL mapping that can use markers with segregation distortion (non-Mendelian markers). An EM (expectation-maximization) algorithm is used to estimate QTL and SDL (segregation distortion loci) parameters. The joint analysis of QTL and SDL is particularly useful for selective genotyping. Application of the joint analysis is demonstrated using a real life data from a wheat QTL mapping experiment.

ON THE MODELS OF SEGREGATION DISTORTION IN DROSOPHILA MELANOGASTER

Genetics ◽  
1979 ◽  
Vol 93 (2) ◽  
pp. 423-435
Author(s):  
Diana W Martin ◽  
Yuichiro Hiraizumi
Keyword(s):  
Drosophila Melanogaster ◽  
Segregation Distortion ◽  
Regulatory Protein ◽  
Segregation Ratio ◽  
Major Elements ◽  
Necessary Condition ◽  
Slight Reduction ◽  
Mendelian Segregation ◽  
Multiple Alleles ◽  
Actual Observation

ABSTRACT The Segregation Distorter system of Drosophila melanogaster consists of two major elements, Sd and Rsp. There are two allelic alternatives of Rsp—sensitive (Rsp8) and insensitive (Rspi); a chromosome carrying Rspi is not distorted. According to the model proposed by HARTL (1973), these two elements interact to cause segregation distortion. For a sperm to complete the maturation process, it is assumed that the Rsp locus has to be complexed with the product of the Sd locus. This product is assumed to be a multimetric regulatory protein. Three kinds of regulatory multimers may be distinguished: Sd+/Sd+, which is assumed to complex with both Rsp8 and Rspi; Sd+/Sd heteromultimers, which complex preferentially with Rspi; and Sd/Sd hmomultimers, which complex with neither Rsp8 nor Rspi. Most of the regulatory protein in the Sd+/Sd heterozygous male is assumed to be the Sd+/Sd heteromultimer. ——Some modifications of HARTL'S model were made by GANETZEY (1977). Rather than the binding of a product of Sd at the Rsp locus being a necessary condition for normal spermigenesis, this binding causes sperm dysfunction. It is assumed that the product of Sd complexes more readily with Rsp8 than with Rspi and that the amount of Sd product is limited with respect to the number of binding sites available. No function is ascribed to the Sd+ locus. In order to explain reduced male fertility of some genotypes, GANETZKY further assumes that the Sd product, when not competed for by an Rsp8 locus, can bind to an Rspi locus.——Two consequences of these models were criticically examined: according to these models (1) an Sd Rsp8/Sd+ RspS male should not show any segregation distortion, and (2) an Sd Rsps/Sd Rsp8 male should show much reduced fertility, if not complete sterility.—The results of the present study bear on these two points. (1) Rsp8 locus seems to consist of multiple alleles, each having a different degree of ability to interact with the product of the Sd locus. An Sd Rsp8/Sd+RspS male shows a certain degree of segregation distortion when the two RspS alleles are different, but it shows a normal Mendelian segregation ratio when the Rsp8 alleles are homozygous. The first prediction of the models is supported by actual observation when the two Rsps alleles are the same. (2) There is a suggestion of slight reduction in fertility, but generally Sd Rsp8/Sd Rsp8 males are quite fertile. Thus, the second prediction is not supported by actual observation. The mechanism of segregation distortion is still open for future studies.

Guiding Principles of Design for Circular Tourism

2020 ◽  
pp. 11-30
Author(s):  
José Miguel Rodríguez-Antón, ◽  
María del Mar Alonso-Almeida
Keyword(s):  
Circular Economy ◽  
System Thinking ◽  
Management Model ◽  
New Paradigm ◽  
British Standard ◽  
New Model ◽  
Tourism Sector ◽  
Guiding Principles ◽  
Principles Of Design

This chapter analyses the guiding principles that companies in the tourism sector should follow to implement a management model that conforms to the new paradigm of the circular economy. To do this, the authors contextualise this new model in the important sector of tourism, creating the concept of circular tourism, and they argue that many of the innovations being incorporated in this sector are oriented to eco-innovation. They also discuss the case of a Spanish urban hotel that has opted for circularity and sustainability, and finally, they propose, in line with the British Standard BS 8001:2017, that the application of the principles of system thinking, innovation, stewardship, collaboration, value optimization, and transparency will help companies in the tourism sector to focus on the new paradigm of the circular economy.

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