scholarly journals Continuous approximations for optimizing allele trajectories

2010 ◽  
Vol 92 (2) ◽  
pp. 157-166 ◽  
Author(s):  
A. Y. H. LIU ◽  
J. A. WOOLLIAMS
Keyword(s):  
Discontinuous Solution ◽  
Selection Procedure ◽  
Time Frame ◽  
Continuous Approximation ◽  
Selection Intensity ◽  
Breeding Schemes ◽  
Selection Intensities ◽  
Accuracy Of Prediction ◽  
Shed Light ◽  
Total Selection

SummaryThe incorporation of genetic information such as quantitative trait loci (QTL) data into breeding schemes has become feasible as DNA technologies have advanced. Such strategies allow the frequency of desirable QTL to be controlled over a predefined time frame, allowing the allele trajectory for QTL to be manipulated. A continuous approximation to changes in allele frequency was developed to approximate the selection procedure as a continuous rather than a discrete process, and analytical solutions were obtained, which shed light on how allele trajectories behave under different objective functions. Three different objectives were considered: (1) minimizing the total selection intensity, (2) minimizing the sum of squared selection intensities and (3) equalizing the selection intensity applied over time. Simulations and genetic algorithms were performed to test the accuracy and robustness of the continuous approximation. Theory shows firstly that the total selection intensity required for moving an allele from a starting frequency to another frequency point can be predicted independent of its trajectory, and secondly that objectives (2) and (3) are equivalent as the number of selection opportunities (T) becomes large. The prediction of total selection intensity provides a good fit for these two objectives, with the accuracy of prediction improving as T increases. However, for (1) the continuous approximation does not fit due to the existence of a discontinuous solution in which the continuous approximation is applied before the frequency of the selected allele reaches 0·5 followed by rapid fixation.

scholarly journals A thin, deformable, high-performance supercapacitor implant that can be biodegraded and bioabsorbed within an animal body

2021 ◽  
Vol 7 (2) ◽  
pp. eabe3097
Author(s):  
Hongwei Sheng ◽  
Jingjing Zhou ◽  
Bo Li ◽  
Yuhang He ◽  
Xuetao Zhang ◽  
...  
Keyword(s):  
High Performance ◽  
Electronic Devices ◽  
Form Factors ◽  
Time Frame ◽  
Water Soluble ◽  
Two Dimensional ◽  
Medical Electronics ◽  
Thin Structure ◽  
Shed Light

It has been an outstanding challenge to achieve implantable energy modules that are mechanically soft (compatible with soft organs and tissues), have compact form factors, and are biodegradable (present for a desired time frame to power biodegradable, implantable medical electronics). Here, we present a fully biodegradable and bioabsorbable high-performance supercapacitor implant, which is lightweight and has a thin structure, mechanical flexibility, tunable degradation duration, and biocompatibility. The supercapacitor with a high areal capacitance (112.5 mF cm−2 at 1 mA cm−2) and energy density (15.64 μWh cm−2) uses two-dimensional, amorphous molybdenum oxide (MoOx) flakes as electrodes, which are grown in situ on water-soluble Mo foil using a green electrochemical strategy. Biodegradation behaviors and biocompatibility of the associated materials and the supercapacitor implant are systematically studied. Demonstrations of a supercapacitor implant that powers several electronic devices and that is completely degraded after implantation and absorbed in rat body shed light on its potential uses.

scholarly journals EFFECTS OF POPULATION SIZE AND SELECTION INTENSITY ON SHORT-TERM RESPONSE TO SELECTION FOR POSTWEANING GAIN IN MICE

Genetics ◽  
1973 ◽  
Vol 73 (3) ◽  
pp. 513-530
Author(s):  
J P Hanrahan ◽  
E J Eisen ◽  
J E Legates
Keyword(s):  
Population Size ◽  
Selection Response ◽  
Selection Intensity ◽  
Realized Heritability ◽  
Family Selection ◽  
Effective Population ◽  
Population Sizes ◽  
Selection For ◽  
Selection Intensities ◽  
Term Response

ABSTRACT The effects of population size and selection intensity on the mean response was examined after 14 generations of within full-sib family selection for postweaning gain in mice. Population sizes of 1, 2, 4, 8 and 16 pair matings were each evaluated at selection intensities of 100% (control), 50% and 25% in a replicated experiment. Selection response per generation increased as selection intensity increased. Selection response and realized heritability tended to increase with increasing population size. Replicate variability in realized heritability was large at population sizes of 1, 2 and 4 pairs. Genetic drift was implicated as the primary factor causing the reduced response and lowered repeatability at the smaller population sizes. Lines with intended effective population sizes of 62 yielded larger selection responses per unit selection differential than lines with effective population sizes of 30 or less.

scholarly journals The English Sweating Sickness: Out of Sight, Out of Mind?

2018 ◽  
Vol 47 (1) ◽  
pp. 102
Author(s):  
Paul Heyman ◽  
Christel Cochez ◽  
Mirsada Hukić
Keyword(s):  
Mortality Rates ◽  
Time Frame ◽  
Epidemiological Features ◽  
Geographical Spread ◽  
Causal Pathogen ◽  
The Subject ◽  
The Right ◽  
Sweating Sickness ◽  
Shed Light

<p>In this paper we aim to add additional knowledge regarding the occurrence, origin and epidemiological features of the English sweating sickness. The English sweating sickness raged in five devastating epidemics with mortality rates between 30 and 50% between 1485 and 1551 throughout England, and on one occasion also affected mainland Europe, in 1529. The Picardy sweat, generally considered as the English sweating sickness’ lesser deadly successor, flared up in France in 1718 and caused 196 localized outbreaks with varying severity all over France and neighboring countries up to 1861. The English sweating sickness has been the subject of numerous attempts to define its origin, but so far all efforts have failed due to lack of material, DNA or RNA, that - using modern techniques and knowledge - could shed light on its cause. Although the time frame in which the English sweating sickness occurred and the geographical spread of the outbreaks is generally known, we will demonstrate here that there was more to it than meets the eye. We found reports of cases of sweating sickness in years before, after and between the 1485, 1508, 1517, 1529 and 1551 epidemics, as well as reports of sweating sickness in Italy and Spain.</p><p><strong>Conclusion. </strong>In spite of the fact that the English sweating sickness apparently has not caused casualties for a more than a century now, we suggest that -given the right circumstances- the possibility of re-emergence might still exist. The fact that up until today we have no indication concerning the causal pathogen of the English sweating sickness is certainly not re-assuring.</p>

scholarly journals EFFECTS OF POPULATION SIZE AND SELECTION INTENSITY ON RESPONSES TO DISRUPTIVE SELECTION IN DROSOPHILA MELANOGASTER

Genetics ◽  
1974 ◽  
Vol 78 (2) ◽  
pp. 715-735
Author(s):  
J S F Barker ◽  
L J E Karlsson
Keyword(s):  
Assortative Mating ◽  
Random Mating ◽  
Female Parent ◽  
Disruptive Selection ◽  
Lethal Gene ◽  
Selection Intensity ◽  
Bristle Number ◽  
Isolation Index ◽  
Selection Intensities ◽  
High Selection

ABSTRACT Disruptive selection for sternopleural bristle number with opportunity for random mating was done in the four treatment combinations of two population sizes (40 pairs and 8 pairs of selected parents) and two selection intensities (1 in 40 and 1 in 2). In each generation, matings among selected parents were observed in a mating chamber, and progeny collected separately from each female parent. In the high number, high selection intensity treatment, divergence between the high and low parts ceased about generation 11. The isolation index increased rapidly to generation 3, but then fluctuated to termination of the population at generation 17. The overall isolation index was significant, indicating a real tendency to assortative mating. The failure of the isolation index to increase after generation 3 was attributed to lower average mating fitness of high males (due to inbreeding) and reduced receptivity of low females (due to a homozygous lethal gene with a large effect on sternopleural bristle number in heterozygotes). In the two low number treatments, isolation indices fluctuated from generation to generation with no obvious trends, and none of the overall isolation indices were significantly different from zero. The high number, low selection intensity treatment showed very little divergence, and one of the replicates showed, in contrast with expectation and the high number, high selection intensity treatment, a significant tendency to disassortative mating. Intense disruptive selection may lead to assortative mating.

Cluster-Based Input Selection for Transparant Fuzzy Modeling

2008 ◽  
pp. 1138-1156
Author(s):  
Can Yang ◽  
Jun Meng ◽  
Shanan Zhu
Keyword(s):  
Computational Cost ◽  
Fuzzy Model ◽  
Selection Procedure ◽  
Specific Model ◽  
Benchmark Problems ◽  
Input Selection ◽  
Model Free ◽  
Interpretable Model ◽  
Data Collections ◽  
Accuracy Of Prediction

Input selection is an important step in nonlinear regression modeling. By input selection, an interpretable model can be built with less computational cost. Input selection thus has drawn great attention in recent years. However, most available input selection methods are model-based. In this case, the input data selection is insensitive to changes. In this paper, an effective model-free method is proposed for the input selection. This method is based on sensitivity analysis using Minimum Cluster Volume (MCV) algorithm. The advantage of our proposed method is that with no specific model needed to be built in advance for checking possible input combinations, the computational cost is reduced and changes of data patterns can be captured automatically. The effectiveness of the proposed method is evaluated by using three well-known benchmark problems, which show that the proposed method works effectively with small and medium sized data collections. With an input selection procedure, a concise fuzzy model is constructed with high accuracy of prediction and better interpretation of data, which serves the purpose of patterns discovery in data mining well.

scholarly journals Optimum selection intensities in artificial selection programmes: an experimental evaluation

1977 ◽  
Vol 30 (2) ◽  
pp. 115-119 ◽  
Author(s):  
R. Frankham
Keyword(s):  
Experimental Evaluation ◽  
Selection Intensity ◽  
Effective Population ◽  
Term Selection ◽  
Optimum Selection ◽  
Selection For ◽  
Selection Intensities ◽  
Selection Of ◽  
Better Than

SUMMARYAn experimental evaluation of Robertson's (1970) theory concerning optimum intensities of selection for selection of varying durations has been carried out using published results from a long term selection study in Drosophila. Agreement of predicted rankings of treatments with expectations was excellent for low values of t/T (generations/total number scored) but poor for larger values of t/T. This was due to the 20% selection intensity treatments responding worse than expected and the 40% treatments relatively better than expected. Several possible reasons for the discrepancies exist but the most likely explanation is considered to be the greater reduction in effective population size due to selection in treatments with more intense selection.

GEOSPATIAL ASSESSMENT BASED ON FERTILITY AND MORTALITY DIFFERENTIAL INDICES OF NATURAL SELECTION IN NORTH-WEST AND EASTERN HIMALAYAN POPULATIONS

2016 ◽  
Vol 49 (6) ◽  
pp. 811-825
Author(s):  
Krishan Sharma
Keyword(s):  
High Altitude ◽  
Secondary Data ◽  
Himachal Pradesh ◽  
Embryonic Mortality ◽  
Human Populations ◽  
Similar Data ◽  
Lower Altitude ◽  
North West ◽  
Selection Intensities ◽  
Total Selection

SummaryThere is contradictory evidence of having fewer live births and higher embryonic mortality among high-altitude populations than their counterparts at lower altitude. This study explores the geospatial differences in selection intensities among human populations living in different ecological settings. Reproductive data from post-menopausal women were collected from 75 women from near Shimla, Himachal Pradesh, at an altitude of 2150 m above sea level and 100 women from Jind, Haryana, at an altitude of 227 m. Secondary data were taken from 85 women from the Kinnaur district of Himachal Pradesh at an average altitude of 3420 m. A comparison of the study data was made with similar data from different populations living in the western and eastern Himalayas. The total selection intensity index based on Johnston and Kensinger’s index was highest in Shimla and lowest in Kinnaur. The fertility selection component was highest in Shimla and lowest in Kinnaur. The prenatal mortality contribution to the total selection was highest in Shimla (30.76%) and lowest in Kinnaur (2.14%), while the contributions of normalized postnatal mortality were 16.39% and 57.80% in Shimla and Kinnaur, respectively. The fertility component of selection was higher than the mortality component in Shimla, while in the other two places the reverse was observed. Hypoxic conditions at high altitude seem to have little effect on the fertility and embryonic mortality rates of indigenous people. The geospatial differences in the selection intensities may be due to differences in ethnic, behavioural ecology, environmental, cultural and socioeconomic factors.

Optimum linear indices for non-linear profit functions

1993 ◽  
Vol 56 (1) ◽  
pp. 43-50 ◽  
Author(s):  
H. Pasternak ◽  
J. I. Weller
Keyword(s):  
Selection Index ◽  
Selection Intensity ◽  
Production Traits ◽  
Milk Production Traits ◽  
Optimum Selection ◽  
Non Linear ◽  
Linear Index ◽  
Standard Linear ◽  
Profit Functions ◽  
Selection Intensities

AbstractAn iterative method is presented, based on the method of Moav and Hill (1966) to derive the optimum linear selection index for any number of traits with linear or non-linear profit functions. For non-linear profit functions the index weights will be functions of the trait means prior to selection and the selection intensity. Using the equations developed, the optimum selection index for three dairy cattle milk production traits was computed. Convergence was obtained after three to four iterations, and was robust to the starting values used for iteration. The ratio of expected genetic gains were only marginally different for selection intensities of 1 and 4 standard deviation units. Differences were greater for the index coefficients. All alternative indices tested gave lower gains in profit than the optimum index. For linear profit functions this index reduces to the standard linear index, and for two uncorrelated traits this index reduces to the index of Moav and Hill (1966).

The value of cloning in MOET nucleus breeding schemes for dairy cattle

1989 ◽  
Vol 48 (1) ◽  
pp. 31-35 ◽  
Author(s):  
J. A. Woolliams
Keyword(s):  
Dairy Cattle ◽  
Selection Intensity ◽  
Genetic Progress ◽  
Selection Accuracy ◽  
Potential Problems ◽  
Breeding Schemes ◽  
Nucleus Breeding

ABSTRACTThe value of cloning in MOET nucleus breeding schemes has to be considered within the constraint of fixed resources. Under this constraint cloning was found to add to genetic progress only when (i) the heritability is low and (ii) it is used at the expense of a reduction in the number of bull families. This course would exacerbate inbreeding and other potential problems with MOET. All other options for using clones lead to a reduction in genetic progress due to a loss of selection intensity that is not made up for by gains in selection accuracy.

scholarly journals Measuring Selection Intensities Among Kolam Population: Manifested through Differential Fertility and Differential Mortality

2019 ◽  
pp. 35-48
Author(s):  
Bharathi K
Keyword(s):  
Andhra Pradesh ◽  
Differential Mortality ◽  
Selection Intensity ◽  
Differential Fertility ◽  
Total Index ◽  
Postnatal Mortality ◽  
History Of ◽  
Telangana State ◽  
Selection Intensities ◽  
Modified Formula

The objective of the study is to understand the selection intensities among Kolam, a particularly vulnerable tribal group (PVTG) of Adilabad district of Telangana State, India. Two prominent methods were employed to understand the intensities by using Crow’s index and modified formula as given by Johnston and Kensinger’s method. The intensities are computed on the basis of the reproductive history of mother with completed fertility and the results were compared with the available works on populations belonging to Andhra Pradesh, Telangana and India. The Crow’s total index (II) value was found to be 0.3863. The mortality (Im) component was found to be 0.2151 while fertility (If) component was found to be 0.1712. The contribution of mortality component is greater than that of fertility component among the present studied population using Crow’s index. According to Johnston and Kensinger, the total index (II) was found to be 0.6017. Fertility component was found to be 0.2368, prenatal mortality component (Ime) and postnatal mortality component (Ime/Pb) where observed to be 0.0675 and 0.0933 respectively. Therefore, it is clear from the results that postnatal mortality contributes more than prenatal mortality for selection, i.e., Johnston and Kensinger’s Index (0.6017) contributes more towards selection intensity than Crow’s index (0.3863). Natural selection takes place when there is variability of fitness observed through the differences in fertility and mortality in any population.

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