Controlled heterozygosity in livestock

1955 ◽  
Vol 144 (915) ◽  
pp. 192-203 ◽  
Keyword(s):  
Single Locus ◽  
Common Method ◽  
Dominance Relations ◽  
Livestock Breeding ◽  
Definition Of

The word heterozygosity appears in the title of this paper in preference to heterosis for three reasons. First, heterosis has different usages and might be misleading. A simple illustration is provided by the colours of Shorthorn cattle which are determined by a pair of alleles. The heterozygotes, which are roan, may fairly be described as intermediate between the red and the white of the two homozygotes, and thus show no dominance and therefore no heterosis. Since, however, breeders prefer roans, they are maintained in breeding herds at a frequency greater than 0·5 (Rendel 1952).* On Dobzhansky’s (1952) definition of heterosis, this would be an example of single-locus heterosis and over-dominance. A similar situation obtains in respect of the white saddle of Wessex Saddleback pigs (Donald 1951). for neither the cattle nor the pigs is there evidence that breeders’ preferences for heterozygotes lead to higher production of meat or milk. Second, too little is known about metrical bias and scaling (Mather 1946) which are basic to a proper onception of the dominance relations involved; and third, heterosis in any current sense is not sufficiently comprehensive to describe the uses which controlled heterozygosity has or might have in livestock breeding. One simple and common method of increasing heterozygosity is to mate animals rawn from two distinct breeds. As may be judged from their appearance and their ross-bred progeny, many of these breeds differ substantially in genotype. The ncrease in heterozygosity consequent on crossing them has the assured merit of Adapting the progeny to market demands and the probable merit of improving Performance through heterosis.

PROBLEMS AND PRIORITY AREAS FOR APPLYING DIGITAL TECHNOLOGIES IN RUSSIAN AGRICULTURE

2020 ◽  
Vol 10 (7) ◽  
pp. 1390-1398
Author(s):  
M A. Bryzgalina ◽  
Keyword(s):  
Mobile Communications ◽  
Business Processes ◽  
Agricultural Sector ◽  
Digital Technologies ◽  
Digital Economy ◽  
Economic Activities ◽  
Agricultural Enterprises ◽  
Livestock Breeding ◽  
Rational Version ◽  
Definition Of

This paper discusses the implementation of digital technologies in the production sector and business processes of agricultural enterprises in Russia. Implementation of digitalization into the economic entities’ business activity is necessary in order not only to increase the speed of their functioning several times, but also to open up new, broader opportunities for their development in the future. Currently, in the Russian Federation, the main leaders in the development of digital technologies are, first of all, IT companies, as well as organizations operating in the field of media, finance and insurance. The level of digitalization in the real sector of the economy is significantly lower, while the agricultural sector is in last place for this indicator. This article reflects the prerequisites for the development of the digital economy in the world, which include the automation of production technologies and business processes, as well as penetration into the social sphere of the countries of the global Internet and mobile communications. The author considered a number of interpretations of the concept of “digital economy”, of which, in her opinion, the most rational version of the definition of the term under consideration was selected. Within the framework of the study, the prerequisites for the effective implementation of innovative technologies in the economic and social spheres of enterprises’ activities were determined, and the main factors and conditions for the developing digital system of a particular country were established. In the presented work, the author identified a number of modern key problems that significantly impede the introduction of digital technologies in the production and economic activities of economic entities of Russia, especially in the field of agriculture. At the same time, quite popular and widespread advanced technologies are indicated, which are currently being successfully implemented in promising agricultural organizations of the country. With regard to the branches of agriculture in Russia, namely crop and livestock breeding, the most expedient areas for the introduction of advanced digital technologies into the business processes of agricultural enterprises are presented.

A Meta-Model-Based Approach to the Definition of the Analysis Results of Petri-Net Models

2013 ◽  
pp. 104-116
Author(s):  
Simona Bernardi ◽  
José Merseguer
Keyword(s):  
Petri Net ◽  
Model Transformation ◽  
Common Method ◽  
System Behavior ◽  
Modeling And Analysis ◽  
Meta Model ◽  
Transformation Rules ◽  
Model Based ◽  
Modeling Techniques ◽  
Definition Of

Multi-formalism modeling techniques enable the modeling and analysis of different aspects of a system. One of the main issues in the integration of multiple tools to support multi-formalisms is how to provide a common method to report the results of the analysis and how to interchange them between models, based on different formalisms, that often represent the system behavior at different granularity levels. In this chapter, the authors focus on the Petri Net formalism, and they present a preliminary work toward the definition of a common XML-based language for the specification of the results obtained from the analysis of Petri net models. The authors use a meta-model based approach, where first a structured set of meta-models representing the Petri net result concepts and their relationships are defined. Then, model transformation rules enable the mapping of meta-models to XML constructs.

scholarly journals Deciphering amphibian diversity through DNA barcoding: chances and challenges

2005 ◽  
Vol 360 (1462) ◽  
pp. 1859-1868 ◽  
Author(s):  
Miguel Vences ◽  
Meike Thomas ◽  
Ronald M Bonett ◽  
David R Vieites
Keyword(s):  
Dna Barcoding ◽  
Single Locus ◽  
Universal Primers ◽  
Nuclear Markers ◽  
Amphibian Species ◽  
Interspecific Divergence ◽  
Candidate Species ◽  
Mitochondrial Population ◽  
Tremendous Amount ◽  
Definition Of

Amphibians globally are in decline, yet there is still a tremendous amount of unrecognized diversity, calling for an acceleration of taxonomic exploration. This process will be greatly facilitated by a DNA barcoding system; however, the mitochondrial population structure of many amphibian species presents numerous challenges to such a standardized, single locus, approach. Here we analyse intra- and interspecific patterns of mitochondrial variation in two distantly related groups of amphibians, mantellid frogs and salamanders, to determine the promise of DNA barcoding with cytochrome oxidase subunit I ( cox1 ) sequences in this taxon. High intraspecific cox1 divergences of 7–14% were observed (18% in one case) within the whole set of amphibian sequences analysed. These high values are not caused by particularly high substitution rates of this gene but by generally deep mitochondrial divergences within and among amphibian species. Despite these high divergences, cox1 sequences were able to correctly identify species including disparate geographic variants. The main problems with cox1 barcoding of amphibians are (i) the high variability of priming sites that hinder the application of universal primers to all species and (ii) the observed distinct overlap of intraspecific and interspecific divergence values, which implies difficulties in the definition of threshold values to identify candidate species. Common discordances between geographical signatures of mitochondrial and nuclear markers in amphibians indicate that a single-locus approach can be problematic when high accuracy of DNA barcoding is required. We suggest that a number of mitochondrial and nuclear genes may be used as DNA barcoding markers to complement cox1 .

scholarly journals Comparison of Single- and Multilocus Genetic Diversity in the Protozoan Parasites Cryptosporidium parvum and C. hominis

2010 ◽  
Vol 76 (19) ◽  
pp. 6639-6644 ◽  
Author(s):  
Giovanni Widmer ◽  
Yongsun Lee
Keyword(s):  
Genetic Diversity ◽  
Cryptosporidium Parvum ◽  
Single Locus ◽  
Surface Glycoprotein ◽  
Protozoan Parasites ◽  
Multilocus Genotypes ◽  
Glycoprotein Gene ◽  
Typing Methods ◽  
Intraspecies Diversity ◽  
Definition Of

ABSTRACT The genotyping of numerous isolates of Cryptosporidium parasites has led to the definition of new species and a better understanding of the epidemiology of cryptosporidiosis. A single-locus genotyping method based on the partial sequence of a polymorphic sporozoite surface glycoprotein gene (GP60) has been favored by many for surveying Cryptosporidium parvum and C. hominis populations. Since genetically distinct Cryptosporidium parasites recombine in nature, it is unclear whether single-locus classifications can adequately represent intraspecies diversity. To address this question, we investigated whether multilocus genotypes of C. parvum and C. hominis cluster according to the GP60 genotype. C. hominis multilocus genotypes did not segregate according to this marker, indicating that for this species the GP60 sequence is not a valid surrogate for multilocus typing methods. In contrast, in C. parvum the previously described “anthroponotic” genotype was confirmed as a genetically distinct subspecies cluster characterized by a diagnostic GP60 allele. However, as in C. hominis, several C. parvum GP60 alleles did not correlate with distinct subpopulations. Given the rarity of some C. parvum GP60 alleles in our sample, the existence of additional C. parvum subgroups with unique GP60 alleles cannot be ruled out. We conclude that with the exception of genotypically distinct C. parvum subgroups, multilocus genotyping methods are needed to characterize C. parvum and C. hominis populations. Unless parasite virulence is controlled at the GP60 locus, attempts to find associations within species or subspecies between GP60 and phenotype are unlikely to be successful.

Cyclical Market Power

2002 ◽  
Vol 36 (1) ◽  
pp. 103-145
Author(s):  
Amitai Aviram
Keyword(s):  
Market Power ◽  
Market Share ◽  
Product Market ◽  
Common Method ◽  
Market Definition ◽  
Barriers To Entry ◽  
Relevant Market ◽  
Market Conditions ◽  
Definition Of

Market power is not ubiquitous; it is limited to certain products, in certain areas, and to certain times. Understanding the limits of the market power possessed by a firm in a given case is essential to the correct assessment of the firm's behavior and its antitrust implications.The most common method used to identify the scope as well as the strength of a firm's market power is through the definition of relevant markets, calculation of market share and identification of relevant market conditions (e.g., barriers to entry). Correct assessment of suspected market power should relate to all the limits on that power. For that reason, when exploring the possibility that a certain firm possesses market power, a product market definition is of limited use without the support of the relevant geographic market definition.This is also true of temporal restraints on market power. Some firms may be expected to possess market power (within certain product and geographical bounds) continuously, until a substantial and unexpected change in the industry diminishes their market power or changes its boundaries.

scholarly journals Completeness-Preserving Dominance Techniques for Satisficing Planning

2018 ◽  
Author(s):  
Álvaro Torralba
Keyword(s):  
Action Selection ◽  
New Method ◽  
Hill Climbing ◽  
Optimal Planning ◽  
Dominance Relations ◽  
Definition Of ◽  
Goal Distance ◽  
Pruning Methods

Dominance pruning methods have recently been introduced for optimal planning. They compare states based on their goal distance to prune those that can be proven to be worse than others. In this paper, we introduce dominance techniques for satisficing planning. We extend the definition of dominance, showing that being closer to the goal is not a prerequisite for dominance in the satisficing setting. We develop a new method to automatically find dominance relations in which a state dominates another if it has achieved more serializable sub-goals. We take advantage of dominance relations in different ways; while in optimal planning their usage focused on dominance pruning and action selection, we also use it to guide enforced hill-climbing search, resulting in a complete algorithm.

scholarly journals Lower Approximation Reduction Based on Discernibility Information Tree in Inconsistent Ordered Decision Information Systems

Symmetry ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 696 ◽  
Author(s):  
Jia Zhang ◽  
Xiaoyan Zhang ◽  
Weihua Xu
Keyword(s):  
Information System ◽  
Information Systems ◽  
Set Theory ◽  
Rough Set ◽  
Rough Set Theory ◽  
Attribute Reduction ◽  
Common Method ◽  
New Method ◽  
Lower Approximation ◽  
Dominance Relations

Attribute reduction is an important topic in the research of rough set theory, and it has been widely used in many aspects. Reduction based on an identifiable matrix is a common method, but a lot of space is occupied by repetitive and redundant identifiable attribute sets. Therefore, a new method for attribute reduction is proposed, which compresses and stores the identifiable attribute set by a discernibility information tree. In this paper, the discernibility information tree based on a lower approximation identifiable matrix is constructed in an inconsistent decision information system under dominance relations. Then, combining the lower approximation function with the discernibility information tree, a complete algorithm of lower approximation reduction based on the discernibility information tree is established. Finally, the rationality and correctness of this method are verified by an example.

Aerodynamic Drag on Trains in Tunnels Part 1: Synthesis and Definitions

1996 ◽  
Vol 210 (1) ◽  
pp. 29-38 ◽  
Author(s):  
A E Vardy
Keyword(s):  
Drag Coefficient ◽  
Drag Force ◽  
Aerodynamic Drag ◽  
Common Method ◽  
Pressure Waves ◽  
Friction Drag ◽  
Pressure Drag ◽  
Normal Forces ◽  
Wide Range ◽  
Definition Of

Aerodynamic drag on trains in tunnels includes friction drag and pressure drag, which are respectively the algebraic sums of the longitudinal components of all shear and normal forces on the train surfaces. The first of these is broadly similar to its counterpart in the open. The second is shown to include two effects that are usually negligible in the open. It is shown that the overall drag force must be regarded as the sum of individual components, each of which behaves differently from the others. The components can be represented by non-dimensional coefficients whose numerical values are nearly constant for a wide range of train journeys. In contrast, the overall drag coefficient is shown to vary significantly, even during any particular journey. The principal causes of aerodynamic drag in tunnels are also the principal causes of pressure waves that give rise to potential aural discomfort for passengers. It is argued that a common method of analysis is appropriate for the prediction of both of these effects. Ill-defined train areas are shown to be a potentially serious source of confusion in the estimation and interpretation of drag coefficients. The relevant train area is shown to be its aerodynamic area, the definition of which is explained.

scholarly journals Population Models of Genomic Imprinting. I. Differential Viability in the Sexes and the Analogy With Genetic Dominance

Genetics ◽  
1999 ◽  
Vol 153 (4) ◽  
pp. 1949-1958 ◽  
Author(s):  
Richard J E Anderson ◽  
Hamish G Spencer
Keyword(s):  
Sex Differences ◽  
Genomic Imprinting ◽  
Population Models ◽  
The Other ◽  
Single Locus ◽  
Genetic Dominance ◽  
Dominance Relations ◽  
Complete Inactivation ◽  
Differential Viability ◽  
Globally Stable

Abstract Many single-locus, two-allele selection models of genomic imprinting have been shown to reduce formally to one-locus Mendelian models with a modified parameter for genetic dominance. One exception is the model where selection at the imprinted locus affects the sexes differently. We present two models of maternal inactivation with differential viability in the sexes, one with complete inactivation, and the other with a partial penetrance for inactivation. We show that, provided dominance relations at the imprintable locus are the same in both sexes, a globally stable polymorphism exists for a range of viabilities that is independent of the penetrance of imprinting. The conditions for a polymorphism are the same as in previous models with differential viability in the sexes but without imprinting and in a model of the paternal X-inactivation system in marsupials. The model with incomplete inactivation is used to illustrate the analogy between imprinting and dominance by comparing equilibrium bifurcation plots for fixed values of dominance and penetrance. We also derive a single expression for the dominance parameter that leaves the frequency and stability of equilibria unchanged for all levels of inactivation. Although an imprinting model with sex differences does not formally reduce to a nonimprinting scheme, close theoretical parallels clearly exist.

Introductory paper

1966 ◽  
Vol 24 ◽  
pp. 3-5
Author(s):  
W. W. Morgan
Keyword(s):  
Line Intensity ◽  
Classification Scheme ◽  
Two Dimensional ◽  
Spectral Classification ◽  
Dimensional Array ◽  
Rr Lyrae ◽  
Metallic Line ◽  
Introductory Paper ◽  
Parameter Varying ◽  
Definition Of

1. The definition of “normal” stars in spectral classification changes with time; at the time of the publication of theYerkes Spectral Atlasthe term “normal” was applied to stars whose spectra could be fitted smoothly into a two-dimensional array. Thus, at that time, weak-lined spectra (RR Lyrae and HD 140283) would have been considered peculiar. At the present time we would tend to classify such spectra as “normal”—in a more complicated classification scheme which would have a parameter varying with metallic-line intensity within a specific spectral subdivision.

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