scholarly journals The generalized Price equation: forces that change population statistics

2020 ◽  
Author(s):  
Steven A. Frank ◽  
William Godsoe
Keyword(s):  
Expected Value ◽  
Frame Of Reference ◽  
Price Equation ◽  
Frequency Change ◽  
Population Composition ◽  
Population Statistics ◽  
The Family ◽  
Population Statistic ◽  
Frequency Changes ◽  
Generalized Partition

The Price equation partitions the change in the expected value of a population measure. The first component describes the partial change caused by altered frequencies. The second component describes the partial change caused by altered measurements. In biology, frequency changes often associate with the direct effect of natural selection. Measure changes reflect processes during transmission that alter trait values. More broadly, the two components describe the direct forces that change population composition and the altered frame of reference that changes measured values. The classic Price equation is limited to population statistics that can expressed as the expected value of a measure. Many statistics cannot be expressed as expected values, such as the harmonic mean and the family of rescaled diversity measures. We generalize the Price equation to any population statistic that can be expressed as a function of frequencies and measurements. We obtain the generalized partition between the direct forces that cause frequency change and the altered frame of reference that changes measurements.

Stimulated electromagnetic shock radiation (SESR) in frequency-dispersive media

1977 ◽  
Vol 55 (17) ◽  
pp. 1499-1509 ◽  
Author(s):  
S. Schneider ◽  
R. Spitzer
Keyword(s):  
Resonance Frequency ◽  
Energy Levels ◽  
Stimulated Emission ◽  
Dispersive Media ◽  
Electron Trajectory ◽  
Frequency Change ◽  
Electromagnetic Shock ◽  
Frequency Changes ◽  
Shock Frequency ◽  
Shock Fronts

The interaction in a frequency-dispersive medium of a coherent electromagnetic wave with an electron moving faster than a critical (Mach) speed produces electromagnetic radiation with novel characteristics. Theory predicts emission of intense radiation in the form of shock fronts at specific angles from the electron trajectory. The shock fronts are correlated with specific frequencies shifted significantly from that of the incident wave. We have named this effect stimulated electromagnetic shock radiation (SESR). The shock frequencies depend dynamically on the populations of the energy levels that give rise to the medium resonances. A given shock frequency changes from below to above the resonance frequency of the medium with which it is associated as the populations of the two energy levels corresponding to this resonance frequency change from an equilibrium distribution to an inverted one. This dynamic resonance crossing points to the possibility of new synergisms between SESR emission and stimulated emission between discrete levels.

Significación de bienestar subjetivo: Rescatando las voces de adolescentes vulnerados en sus derechos. / Significance of subjective well-being: Rescuing the voices of vulnerable adolescents in their rights

2016 ◽  
Vol 5 (10) ◽  
pp. 49-70
Author(s):  
Francisca León Becerra ◽  
Johana Falcón Pinto
Keyword(s):  
Content Analysis ◽  
Qualitative Methodology ◽  
Well Being ◽  
Frame Of Reference ◽  
Subjective Well Being ◽  
Child Population ◽  
The Family

El bienestar se promueve hace muchos años, especialmente se vela por él en la población infanto-juvenil, sin embargo, cuando se pregunta qué es el bienestar muchas son las respuestas, pero pocas las investigaciones respecto a la infancia y menos contextualizadas en situaciones de vulneración de derechos, considerando que son a quienes más se pretende proteger. Es aquí, cuando es necesario escuchar a los adolescentes que han sido vulnerados en sus derechos respecto a la significación de su bienestar subjetivo expresándolo desde su marco de referencia. Con el objetivo de profundizar en las experiencias se utilizó una metodología cualitativa para entender desde la fenomenología los relatos de seis adolescentes pertenecientes al Programa Especializado en Calle (PEC-Renca), que a través del análisis de contenido de categorización emergente, se llegó a los hallazgos que en la significación del bienestar subjetivo de estos adolescentes prima la familia como fuente de todo aquello que les proporciona bienestar, estando juntos en un mismo hogar, con vínculos afectivos y en donde se ejerza una crianza parental. Influyendo así, la familia en todas las áreas de la vida de los adolescentes. Welfare is promoted for many years, especially it watches over him in the child population, however, when asked what is the welfare there are many answers, but little research regarding children and less contextualized in situations of violation of rights, believing them to be protected more. It is here when you need to listen to adolescents who have been violated in their rights regarding the significance of expressing their subjective well-being from their frame of reference. In order to deepen the experience a qualitative methodology to understand from the phenomenology the stories of six teenagers belonging to the Special Street (PEC-Renca) was used, that through content analysis of emerging categorization, it was the findings on the significance of subjective well-being of these adolescents premium family as the source of everything that provides well-being together in the same household, with bonding and wherein aparental upbringing is exercised. Thus influencing the family in all areas of life of adolescents.

scholarly journals Simple unity among the fundamental equations of science

2020 ◽  
Vol 375 (1797) ◽  
pp. 20190351 ◽  
Author(s):  
Steven A. Frank
Keyword(s):  
Information Theory ◽  
Natural Selection ◽  
Frame Of Reference ◽  
Price Equation ◽  
Physical Work ◽  
Total Probability ◽  
Theme Issue ◽  
Total Change ◽  
Fundamental Equations ◽  
Change Concerns

The Price equation describes the change in populations. Change concerns some value, such as biological fitness, information or physical work. The Price equation reveals universal aspects for the nature of change, independently of the meaning ascribed to values. By understanding those universal aspects, we can see more clearly why fundamental mathematical results in different disciplines often share a common form. We can also interpret more clearly the meaning of key results within each discipline. For example, the mathematics of natural selection in biology has a form closely related to information theory and physical entropy. Does that mean that natural selection is about information or entropy? Or do natural selection, information and entropy arise as interpretations of a common underlying abstraction? The Price equation suggests the latter. The Price equation achieves its abstract generality by partitioning change into two terms. The first term naturally associates with the direct forces that cause change. The second term naturally associates with the changing frame of reference. In the Price equation’s canonical form, total change remains zero because the conservation of total probability requires that all probabilities invariantly sum to one. Much of the shared common form for the mathematics of different disciplines may arise from that seemingly trivial invariance of total probability, which leads to the partitioning of total change into equal and opposite components of the direct forces and the changing frame of reference. This article is part of the theme issue ‘Fifty years of the Price equation’.

scholarly journals Cortical Processing of Frequency Changes Reflected by the Acoustic Change Complex in Adult Cochlear Implant Users

2018 ◽  
Vol 23 (3) ◽  
pp. 152-164 ◽  
Author(s):  
Chun Liang ◽  
Lisa M. Houston ◽  
Ravi N. Samy ◽  
Lamiaa Mohamed Ibrahim Abedelrehim ◽  
Fawen Zhang
Keyword(s):  
Speech Perception ◽  
Cochlear Implant ◽  
Change Detection ◽  
Detection Threshold ◽  
Auditory Evoked Potential ◽  
Frequency Change ◽  
Large Variability ◽  
Frequency Changes ◽  
Acoustic Change Complex ◽  
Electroencephalographic Recording

The purpose of this study was to examine neural substrates of frequency change detection in cochlear implant (CI) recipients using the acoustic change complex (ACC), a type of cortical auditory evoked potential elicited by acoustic changes in an ongoing stimulus. A psychoacoustic test and electroencephalographic recording were administered in 12 postlingually deafened adult CI users. The stimuli were pure tones containing different magnitudes of upward frequency changes. Results showed that the frequency change detection threshold (FCDT) was 3.79% in the CI users, with a large variability. The ACC N1’ latency was significantly correlated with the FCDT and the clinically collected speech perception score. The results suggested that the ACC evoked by frequency changes can serve as a useful objective tool in assessing frequency change detection capability and predicting speech perception performance in CI users.

scholarly journals Combining Experimental Evolution and Genomics to Understand How Seed Beetles Adapt to a Marginal Host Plant

Genes ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 400 ◽  
Author(s):  
Alexandre Rêgo ◽  
Samridhi Chaturvedi ◽  
Amy Springer ◽  
Alexandra M. Lish ◽  
Caroline L. Barton ◽  
...  
Keyword(s):  
Gene Expression ◽  
Allele Frequency ◽  
Development Time ◽  
Callosobruchus Maculatus ◽  
Parallel Evolution ◽  
Frequency Change ◽  
Multiple Traits ◽  
Population Genomic ◽  
Performance Traits ◽  
Frequency Changes

Genes that affect adaptive traits have been identified, but our knowledge of the genetic basis of adaptation in a more general sense (across multiple traits) remains limited. We combined population-genomic analyses of evolve-and-resequence experiments, genome-wide association mapping of performance traits, and analyses of gene expression to fill this knowledge gap and shed light on the genomics of adaptation to a marginal host (lentil) by the seed beetle Callosobruchus maculatus. Using population-genomic approaches, we detected modest parallelism in allele frequency change across replicate lines during adaptation to lentil. Mapping populations derived from each lentil-adapted line revealed a polygenic basis for two host-specific performance traits (weight and development time), which had low to modest heritabilities. We found less evidence of parallelism in genotype-phenotype associations across these lines than in allele frequency changes during the experiments. Differential gene expression caused by differences in recent evolutionary history exceeded that caused by immediate rearing host. Together, the three genomic datasets suggest that genes affecting traits other than weight and development time are likely to be the main causes of parallel evolution and that detoxification genes (especially cytochrome P450s and beta-glucosidase) could be especially important for colonization of lentil by C. maculatus.

scholarly journals The use of selection experiments for detecting quantitative trait loci

1997 ◽  
Vol 69 (3) ◽  
pp. 227-232 ◽  
Author(s):  
L. OLLIVIER ◽  
L. A. MESSER ◽  
M. F. ROTHSCHILD ◽  
C. LEGAULT
Keyword(s):  
Quantitative Trait ◽  
Marker Locus ◽  
Frequency Change ◽  
Gene Frequencies ◽  
Marker Allele ◽  
Gene Effects ◽  
Selection Experiments ◽  
Frequency Changes ◽  
Combined Selection ◽  
Number Of Individuals

Gene frequency changes following selection may reveal the existence of gene effects on the trait selected. Loci for the selected quantitative trait (SQTL) may thus be detected. Additionally, one can estimate the average effect (α) of a marker allele associated with an SQTL from the allele frequency change (Δq) due to selection of given intensity (i). In a sample of unrelated individuals, it is optimal to select the upper and lower 27% for generating Δq in order to estimate α. For a given number of individuals genotyped, this estimator is 0·25i2 times more efficient than the classical estimator of α, based on the regression of the trait on the genotype at the marker locus. The method is extended to selection criteria using information from relatives, showing that combined selection considerably increases the efficiency of estimation for traits of low heritability. The method has been applied to the detection of SQTL in a selection experiment in which the trait selected was pig litter size averaged over the first four parities, with i=3. Results for four genes are provided, one of which yielded a highly significant effect. The conditions required for valid application of the method are discussed, including selection experiments over several generations. Additional advantages of the method can be anticipated from determining gene frequencies on pooled samples of blood or DNA.

scholarly journals The promise and deceit of genomic selection component analyses

2021 ◽  
Vol 288 (1961) ◽  
Author(s):  
John K. Kelly
Keyword(s):  
Allele Frequency ◽  
Statistical Power ◽  
Field Experiments ◽  
Whole Genome Sequence ◽  
Frequency Change ◽  
Genome Wide ◽  
Pooled Sequencing ◽  
Frequency Changes ◽  
Selection Intensities ◽  
Combine Information

Selection component analyses (SCA) relate individual genotype to fitness components such as viability, fecundity and mating success. SCA are based on population genetic models and yield selection estimates directly in terms of predicted allele frequency change. This paper explores the statistical properties of gSCA: experiments that apply SCA to genome-wide scoring of SNPs in field sampled individuals. Computer simulations indicate that gSCA involving a few thousand genotyped samples can detect allele frequency changes of the magnitude that has been documented in field experiments on diverse taxa. To detect selection, imprecise genotyping from low-level sequencing of large samples of individuals provides much greater power than precise genotyping of smaller samples. The simulations also demonstrate the efficacy of ‘haplotype matching’, a method to combine information from a limited collection of whole genome sequence (the reference panel) with the much larger sample of field individuals that are measured for fitness. Pooled sequencing is demonstrated as another way to increase statistical power. Finally, I discuss the interpretation of selection estimates in relation to the Beavis effect, the overestimation of selection intensities at significant loci.

scholarly journals Hybrid capture-based sequencing enables unbiased recovery of SAR-CoV-2 genomes from fecal samples and characterization of the dynamics of intra-host variants

2020 ◽  
Author(s):  
Yi Xu ◽  
Lu Kang ◽  
Zijie Shen ◽  
Xufang Li ◽  
Weili Wu ◽  
...  
Keyword(s):  
Gastrointestinal Tract ◽  
Genomic Diversity ◽  
Clinical Samples ◽  
Frequency Change ◽  
Random Drift ◽  
Genome Coverage ◽  
Fecal Samples ◽  
Hybrid Capture ◽  
Capture Method ◽  
Frequency Changes

AbstractBackgroundIn response to the current COVID-19 pandemic, it is crucial to understand the origin, transmission, and evolution of SARS-CoV-2, which relies on close surveillance of genomic diversity in clinical samples. Although the mutation at the population level had been extensively investigated, how the mutations evolve at the individual level is largely unknown, partly due to the difficulty of obtaining unbiased genome coverage of SARS-CoV-2 directly from clinical samples.MethodsEighteen time series fecal samples were collected from nine COVID-19 patients during the convalescent phase. The nucleic acids of SARS-CoV-2 were enriched by the hybrid capture method with different rounds of hybridization.ResultsBy examining the sequencing depth, genome coverage, and allele frequency change, we demonstrated the impeccable performance of the hybrid capture method in samples with Ct value < 34, as well as significant improvement comparing to direct metatranscriptomic sequencing in samples with lower viral loads. We identified 229 intra-host variants at 182 sites in 18 fecal samples. Among them, nineteen variants presented frequency changes > 0.3 within 1-5 days, reflecting highly dynamic intra-host viral populations. Meanwhile, we also found that the same mutation showed different frequency changes in different individuals, indicating a strong random drift. Moreover, the evolving of the viral genome demonstrated that the virus was still viable in the gastrointestinal tract during the convalescent period.ConclusionsThe hybrid capture method enables reliable analyses of inter- and intra-host variants of SARS-CoV-2 genome, which changed dramatically in the gastrointestinal tract; its clinical relevance warrants further investigation.

scholarly journals Predicting frequency changes of global-scale solar Rossby modes due to solar cycle changes in internal rotation

2020 ◽  
Vol 640 ◽  
pp. L10 ◽  
Author(s):  
C. R. Goddard ◽  
A. C. Birch ◽  
D. Fournier ◽  
L. Gizon
Keyword(s):  
Internal Rotation ◽  
Large Scale ◽  
Peak Frequency ◽  
Global Scale ◽  
Frequency Change ◽  
Theory Approach ◽  
Time Varying ◽  
Solar Cycles ◽  
Frequency Changes ◽  
The Impact

Context. Large-scale equatorial Rossby modes have been observed on the Sun over the last two solar cycles. Aims. We investigate the impact of the time-varying zonal flows on the frequencies of Rossby modes. Methods. A first-order perturbation theory approach is used to obtain an expression for the expected shift in the mode frequencies due to perturbations in the internal rotation rate. Results. Using the time-varying rotation from helioseismic inversions we predict the changes in Rossby mode frequencies with azimuthal orders from m = 1 to m = 15 over the last two solar cycles. The peak-to-peak frequency change is less than 1 nHz for the m = 1 mode, grows with m, and reaches 25 nHz for m = 15. Conclusions. Given the observational uncertainties on mode frequencies due to the finite mode lifetimes, we find that the predicted frequency shifts are near the limit of detectability.

Sign in / Sign up

Export Citation Format

Share Document