scholarly journals Quantitative traits under selection: derivations of distributions, higher moments, and the effects of recombination

2021 ◽  
Author(s):  
Reginald D Smith
Keyword(s):  
Quantitative Traits ◽  
Exact Formula ◽  
Breeding Value ◽  
Breeding Values ◽  
Mean And Variance ◽  
The Mean ◽  
The Impact ◽  
First Four Moments ◽  
First Time ◽  
Fertile Area

The mathematical theory of quantitative traits is over one hundred years old but it is still a fertile area for research and analysis. However, the effects of selection on a quantitative trait, while well understood for the effects on the mean and variance, have traditionally been difficult to attack from the perspective of analyzing the probability density of the breeding values and deriving higher (third and fourth) moments as well as analyzing the impact of recombination. In this paper, the exact formula for the breeding value distribution after selection is derived and, using new integral tables, the first four moments are given exact expressions for the first time. In addition, the effects of recombination on the full distribution of breeding values are demonstrated. Finally, the changes of GXE covariance in the selected parent population caused by factors similar to the Bulmer Effect are also investigated in detail.

scholarly journals Spatial and temporal variations of CO<sub>2</sub> mole fractions observed at Beijing, Xianghe and Xinglong in North China

2021 ◽  
Author(s):  
Yang Yang ◽  
Minqiang Zhou ◽  
Ting Wang ◽  
Bo Yao ◽  
Pengfei Han ◽  
...  
Keyword(s):  
Seasonal Variations ◽  
Human Activities ◽  
North China ◽  
Terrestrial Ecosystem ◽  
Temporal Variations ◽  
Spatial And Temporal Variations ◽  
Boundary Layer Height ◽  
The Mean ◽  
The Impact ◽  
First Time

Abstract. Atmospheric CO2 mole fractions are observed at Beijing (BJ), Xianghe (XH), and Xinglong (XL) in North China using the Picarro G2301 Cavity Ring-Down Spectroscopy instruments. The measurement system is described comprehensively for the first time. The geo-distances among these three sites are within 200 km, but they have very different surrounding environments: BJ is inside the megacity; XH is in the suburban area; XL is in the countryside on a mountain. The mean and standard deviation of CO2 mole fractions at BJ, XH, and XL between October 2018 and September 2019 are 448.4 ± 12.8 ppm, 436.0 ± 9.2 ppm and 420.6 ± 8.2 ppm, respectively. The seasonal variations of CO2 at these three sites are similar, with a maximum in winter and a minimum in summer, which is dominated by the terrestrial ecosystem. However, the seasonal variations of CO2 at BJ and XH are more affected by human activities as compared to XL. By using CO2 at XL as the background, CO2 enhancements are observed simultaneously at BJ and XH. The diurnal variations of CO2 are driven by the boundary layer height, photosynthesis and human activities at BJ, XH and XL. Moreover, we address the impact of the wind on the CO2 mole fractions at BJ and XL. This study provides an insight into the spatial and temporal variations of CO2 mole fractions in North China.

scholarly journals The Impact Of Financial Crisis On Islamic And Conventional Indices Of The GCC Countries

2015 ◽  
Vol 31 (2) ◽  
pp. 357 ◽  
Author(s):  
Hela Miniaoui ◽  
Hameedah Sayani ◽  
Anissa Chaibi
Keyword(s):  
Financial Crisis ◽  
The Other ◽  
Garch Models ◽  
Use Of Data ◽  
Market Index ◽  
Gcc Countries ◽  
Mean And Variance ◽  
The Mean ◽  
The Impact ◽  
Study Performance

<p>We study performance of Islamic and conventional indices of the Gulf Cooperation Council (GCC) countries in the wake of financial crisis of 2008 and test whether Islamic indices were less risky than conventional indices. We make use of data of the six GCC markets as well as the Dow Jones Islamic Market Index GCC. The mean and variance of each of the indices are analyzed based on augmented GARCH models. The results show that the financial crisis impacted on the mean returns of Bahrain, the other indices remained unaffected. The financial crisis, however, impacted volatility in three GCC markets (Kuwait, Bahrain, and the UAE), while the impact on the remaining markets (Saudi Arabia, Oman, and Qatar) and the Islamic index was insignificant. More interestingly, we show that the Islamic index did not exhibit lower volatility than its conventional counterparts.</p>

Selection of parents and estimation of genetic parameters using BLUP and molecular methods for lentil (Lens culinaris Medik.) breeding program in Argentina

2019 ◽  
Vol 56 (1) ◽  
pp. 12-25
Author(s):  
Carolina Bermejo ◽  
Federico Cazzola ◽  
Fernando Maglia ◽  
Enrique Cointry
Keyword(s):  
Quantitative Traits ◽  
Genetic Parameters ◽  
Selection Process ◽  
Recombinant Inbred Lines ◽  
Correlation Coefficients ◽  
Cost Effective ◽  
Molecular Data ◽  
Breeding Value ◽  
Breeding Values ◽  
High Yields

AbstractThe most important objective of lentil breeding programs is to develop new genotypes that are genetically more productive. Besides, it is necessary that the varieties obtained have short flowering cycles to allow the later sowing of summer crops. Selection is based through phenotypic means; however, we argue it should be based on genetic or breeding values because quantitative traits are often influenced by environments and genotype–environment interactions. The objectives of this study were to: (i) identify genotypes with the highest merit; (ii) estimate genetic parameters to know the genetic control of morphological traits in macrosperma and microsperma lentil types using best linear unbiased prediction (BLUP). Twenty-five recombinant inbred lines (RILs) from six F4 families selected on the basis of precocity and high yields were tested in four environments for important quantitative traits. The analysis of variance showed significant differences between genotypes, environments, and genotype–environment interactions for all the traits. Seven macrosperma- and two microsperma-type RILs were selected. Based on average ranking from breeding values and molecular data obtained with sequence-related amplified polymorphism (SRAP), the same genotypes were selected. Genotypic coefficients of variation, heritability across and by environment, and genetic correlation coefficients using BLUP were obtained. According to our results BLUP could replace molecular analysis methods because the selection process was simpler, more cost-effective, and more accurate. The breeding value of parents would give a better ranking of their genetic value than would their phenotypic value; therefore, the selection efficiency would be enhanced and the genetic gain would be more predictable. The selected genotypes could become potential commercial varieties or be used as parental lines in future hybridization programs.

THE ANALYSIS OF SINGLETONS IN GENERALIZED BIRTHDAY PROBLEMS

2012 ◽  
Vol 26 (2) ◽  
pp. 245-262 ◽  
Author(s):  
Matthijs R. Koot ◽  
Michel Mandjes
Keyword(s):  
Iterative Scheme ◽  
Demographic Data ◽  
Homogeneous Distribution ◽  
Birthday Problem ◽  
Mean And Variance ◽  
The Mean ◽  
The Impact

This paper describes techniques to characterize the number of singletons in the setting of the generalized birthday problem, that is, the birthday problem in which the birthdays are non-uniformly distributed over the year. Approximations for the mean and variance presented which explicitly indicate the impact of the heterogeneity (expressed in terms of the Kullback–Leibler distance with respect to the homogeneous distribution). Then an iterative scheme is presented for determining the distribution of the number of singletons. The approximations are validated by experiments with demographic data.

Impact of liveweight, fat and muscle sire breeding values on ewe reproduction is minimal but variable across Australian grazing systems

2017 ◽  
Vol 57 (9) ◽  
pp. 1952 ◽  
Author(s):  
S. F. Walkom ◽  
D. J. Brown
Keyword(s):  
Body Condition ◽  
Reproductive Performance ◽  
Breeding Value ◽  
Production Cycle ◽  
Eye Muscle ◽  
Breeding Values ◽  
Reproduction Traits ◽  
Reproductive Rates ◽  
Supplementary Feed ◽  
The Impact

Australian sheep producers have the potential to improve reproductive rates through optimising ewe body condition across the production cycle. Managing ewe body condition can become costly when supplementary feeding is required due to poor pasture growth or rainfall and by using appropriate genetics, producers can theoretically reduce the flock’s dependency on supplementary feed and improve reproductive rates. Reproductive records from the Information Nucleus Flock and Sheep Genetics Merino and maternal breed datasets were analysed to examine the influence of sire breeding values for liveweight (post-weaning, yearling and adult assessments), fat and eye muscle depths (post-weaning and yearling assessments) and number of lambs weaned on reproductive performance (fertility, litter size and number of lambs born) across a variety of production environments. To determine the impact of environmental conditions on the relationship between weight, ultrasound body composition, and reproduction traits the daughters’ adjusted reproductive performances were regressed on the sire’s breeding value across flocks, within flocks and within flock × year. Irrespective of age at assessment, sire breeding values for liveweight, fat and eye muscle depths had very little association with the reproductive performance of their daughters, on average. The regressions of reproduction on weight, and fat and eye muscle depth traits varied across flocks from unfavourable to favourable estimates. The very small overall impact of weight, and fat and eye muscle depth traits, on average suggests that using sire breeding values for number of lambs weaned, which had a large impact on reproduction, will provide the most viable method to genetically improve reproductive performance within the production system in question.

scholarly journals The Impact of a Nanocellulose-Based Wound Dressing in the Management of Thermal Injuries in Children: Results of a Retrospective Evaluation

Life ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 212
Author(s):  
Julia Cattelaens ◽  
Laura Turco ◽  
Luc M. Berclaz ◽  
Birgit Huelsse ◽  
Wolfgang Hitzl ◽  
...  
Keyword(s):  
Wound Dressing ◽  
Pediatric Patients ◽  
Wound Dressings ◽  
Retrospective Evaluation ◽  
Thermal Injuries ◽  
Hospital Stays ◽  
The Mean ◽  
The Impact ◽  
First Time

The aim of this retrospective study is to evaluate for the first time the impact of a nanocellulose-based wound dressing in the treatment of pediatric patients with both partial- and deep-thickness burns. Usability and effectiveness were defined based on parameters such as frequency of dressing changes under narcosis, duration of hospital stay, onset of complications, need for additional treatments, and follow up scar formation assessment. Fifty-six children who sustained burns in the year 2018 and were treated with a nanocellulose-based wound dressing were included in the trial. The mean stay in hospital was 6.7 days. Patients underwent dressing changes under narcosis 2.4 times on average, and none had wound-associated infection. In all, 82% of the patients were treated only with nanocellulose-based wound dressings, and reepithelialization occurred after ten days. The majority of patients had scars with normal pigmentation (98%), vascularization (91%), height (92%), and pliability (92%). In conclusion, using a nanocellulose-based wound dressing for the treatment of both superficial, partial-thickness and deep, full-thickness burns has several advantages. Compared with the results published in literature on other wound dressings, it requires a moderate number of dressing changes under narcosis and results in short hospital stays. Additionally, it has a low associated infection rate and promotes wound healing.

scholarly journals Payments under the Average Crop Revenue Program: Implications for Government Costs and Producer Preferences

2009 ◽  
Vol 38 (1) ◽  
pp. 49-64 ◽  
Author(s):  
Joseph Cooper
Keyword(s):  
Stochastic Model ◽  
Coefficient Of Variation ◽  
Total Revenue ◽  
Mean And Variance ◽  
The Mean ◽  
Peripheral Production ◽  
The Impact ◽  
To Receive ◽  
Payment Rate ◽  
The U.S

This paper develops a stochastic model for comparing payments to U.S. corn producers under the U.S. Senate's Average Crop Revenue Program (ACR) versus payments under the price-based marketing loan benefit and countercyclical payment programs. Using this model, the paper examines the sensitivity of the density function for payments to changes in expected price levels. We also assess the impact of the choice of yield aggregation used in the ACR payment rate on the mean and variance of farm returns. We find that ACR payments lower the producer's coefficient of variation of total revenue more than does the price-based support, although ACR may not raise mean revenue as much. While corn farmers in the heartland states might still prefer to receive the traditional forms of support when prices are low relative to statutory loan rates and target prices, this outcome is not necessarily the case for farmers in peripheral production regions.

A stochastic theory of community food webs. IV. Theory of food chain lengths in large webs

1986 ◽  
Vol 228 (1252) ◽  
pp. 355-377 ◽  
Keyword(s):  
Food Webs ◽  
Stochastic Theory ◽  
Exact Formula ◽  
Cascade Model ◽  
Quantitative Relation ◽  
Number Of Species ◽  
Mean And Variance ◽  
The Mean ◽  
Chain Lengths ◽  
Median Height

This paper develops a theory of the length of food chains in community food webs. The theory derives from a mathematical model of webs called the cascade model. Our analysis concerns the behaviour of chain lengths for webs in which the number, S , of species is large. From an exact formula for the expected number of chains of each length, we derive a theoretical mean and variance of the length of chains in webs with a given S . For webs in which S becomes large, we compute the asymptotic distribution of the length of a randomly chosen chain, giving explicit closed-form formulas for the asymptotic mean and variance. The cascade model implies a simple rule of thumb for large webs: the mean length of chains approximately equals the mean number of predators plus prey of any species in the web. Such a quantitative relation between mean chain length and the number of links per species appears to be new. The height of a web is defined as the length (number of links) in its longest chain. We show that, according to the cascade model, the median height increases very slowly with the number of species in a web. Indeed, the median height is below 17 for S up to one million. This analysis provides the first quantitative explanation, we believe, of why the longest chains are very short relative to the number of species in a web, even when the number of species is very large. As a theoretical curiosity, we show, for webs in which S becomes unrealistically large, that the height equals one of two adjacent integers with a probability that slowly approaches 1. With increasing S , these two integers approximate ln S /ln (In S ), and thus grow extremely slowly.

SCALING PROPERTIES OF FIRST RETURN TIME ON WEIGHTED TRANSFRACTALS (1,3)-FLOWERS

Fractals ◽  
2018 ◽  
Vol 26 (06) ◽  
pp. 1850095 ◽  
Author(s):  
MEIFENG DAI ◽  
HUIJIA CHI ◽  
XIANBIN WU ◽  
YUE ZONG ◽  
WENJING FENG ◽  
...  
Keyword(s):  
Complex Networks ◽  
Real Life ◽  
Probability Generating Function ◽  
Return Time ◽  
Exact Probability ◽  
Scaling Properties ◽  
Mean And Variance ◽  
The Mean ◽  
First Return Time ◽  
The Impact

Complex networks are omnipresent in science and in our real life, and have been the focus of intense interest. It is vital to research the impact of their characters on the dynamic progress occurring on complex networks for weight-dependent walk. In this paper, we first consider the weight-dependent walk on one kind of transfractal (or fractal) which is named the weighted transfractal [Formula: see text]-flowers. And we pay attention to the first return time (FRT). We mainly calculate the mean and variance of FRT for a prescribed hub (i.e. the most concerned nodes) in virtue of exact probability generating function and its properties. Then, we obtain the mean and the secondary moment of the first return time. Finally, using the relationship among the variance, mean and the secondary moment, we obtain the variance of FRT and the scaling properties of the mean and variance of FRT on weighted transfractals [Formula: see text]-flowers.

scholarly journals Generalizing Cloud Overlap Treatment to Include Solar Zenith Angle Effects on Cloud Geometry

2007 ◽  
Vol 64 (6) ◽  
pp. 2116-2125 ◽  
Author(s):  
Adrian M. Tompkins ◽  
Francesca Di Giuseppe
Keyword(s):  
Zenith Angle ◽  
Large Scale ◽  
Solar Zenith Angle ◽  
Forecast Model ◽  
Simple Extension ◽  
Scale Models ◽  
Field Geometry ◽  
The Mean ◽  
The Impact ◽  
First Time

Shortwave radiative transfer depends on the cloud field geometry as viewed from the direction of the sun. To date, the radiation schemes of large-scale models only consider a zenith view of the cloud field, and the apparent change in the cloud geometry with decreasing solar zenith angle is neglected. A simple extension to an existing cloud overlap scheme is suggested to account for this for the first time. It is based on the assumption that at low sun angles, the overlap between cloud elements is random for an unscattered photon. Using cloud scenes derived from radar retrievals at two European sites, it is shown that the increase of the apparent cloud cover with a descending sun is reproduced very well with the new scheme. Associated with this, there is a marked reduction in the mean radiative biases averaged across all solar zenith angles with respect to benchmark calculations. The scheme is implemented into the ECMWF global forecast model using imposed sea surface temperatures, and while the impact on the radiative statistics is significant, the feedback on the large-scale dynamics is minimal.

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