scholarly journals ANCESTRAL CHARACTER ESTIMATION UNDER THE THRESHOLD MODEL FROM QUANTITATIVE GENETICS

Evolution ◽  
2013 ◽  
Vol 68 (3) ◽  
pp. 743-759 ◽  
Author(s):  
Liam J. Revell
Keyword(s):  
Quantitative Genetics ◽  
Threshold Model ◽  
Ancestral Character Estimation

scholarly journals Evolutionary demography and quantitative genetics: age-specific survival as a threshold trait

2010 ◽  
Vol 278 (1702) ◽  
pp. 144-151 ◽  
Author(s):  
Jacob A. Moorad ◽  
Daniel E. L. Promislow
Keyword(s):  
Quantitative Genetics ◽  
First Principles ◽  
Threshold Model ◽  
Specific Model ◽  
Survival Models ◽  
Delayed Senescence ◽  
Threshold Trait ◽  
Quantitative Genetic ◽  
Evolutionary Demography ◽  
The Standard Model

Researchers must understand how mutations affect survival at various ages to understand how ageing evolves. Many models linking mutation to age-specific survival have been proposed but there is little evidence to indicate which model is most appropriate. This is a serious problem because the predicted evolutionary endpoints of ageing depend upon the details of the specific model. We apply an explicitly quantitative genetic perspective to the problem. To determine the inheritance of dichotomous traits (such as survival), quantitative genetics has long employed a threshold model. Beginning from first principles, we show how this is the most defensible mutational model for age-specific survival and how this, relative to the standard model, predicts delayed senescence and mortality deceleration at late age. These are commonly observed patterns of ageing that heretofore have required more complicated survival models. We also show how this model can be developed further to unify quantitative genetics and evolutionary demography into a more complete conceptual framework for understanding the evolution of ageing.

Hyperstimulation of the immune system as a cause of autoimmune diseases

2020 ◽  
Vol 75 (3) ◽  
pp. 204-213
Author(s):  
Varvara A. Ryabkova ◽  
Leonid P. Churilov ◽  
Yehuda Shoenfeld
Keyword(s):  
Immune System ◽  
Autoimmune Diseases ◽  
Genetic Basis ◽  
Threshold Model ◽  
Subsequent Development ◽  
Threshold Effect ◽  
Successful Management ◽  
Polygenic Inheritance ◽  
Autoimmune Pathology ◽  
The Common

The pathogenesis of autoimmune diseases is very complex and multi-factorial. The concept of Mosaics of Autoimmunity was introduced to the scientific community 30 years ago by Y. Shoenfeld and D.A. Isenberg, and since then new tiles to the puzzle are continuously added. This concept specifies general pathological ideas about the multifactorial threshold model for polygenic inheritance with a threshold effect by the action of a number of external causal factors as applied to the field of autoimmunology. Among the external factors that can excessively stimulate the immune system, contributing to the development of autoimmune reactions, researchers are particularly interested in chemical substances, which are widely used in pharmacology and medicine. In this review we highlight the autoimmune dynamics i.e. a multistep pathogenesis of autoimmune diseases and the subsequent development of lymphoma in some cases. In this context several issues are addressed namely, genetic basis of autoimmunity; environmental immunostimulatory risk factors; gene/environmental interaction; pre-clinical autoimmunity with the presence of autoantibodies; and the mechanisms, underlying lymphomagenesis in autoimmune pathology. We believe that understanding the common model of the pathogenesis of autoimmune diseases is the first step to their successful management.

House Prices, Bank Instability, and Economic Growth: Evidence from the Threshold Model

CFA Digest ◽  
2013 ◽  
Vol 43 (3) ◽  
Author(s):  
Florian B. Schweizer
Keyword(s):  
Economic Growth ◽  
House Prices ◽  
Threshold Model

Threshold square model of the dependence of radiation effects on radiation dose

2020 ◽  
Vol 89 ◽  
pp. 65-74
Author(s):  
A. G. Zavorotnyy ◽  
Keyword(s):  
Radiation Dose ◽  
Emergency Services ◽  
Least Squares Method ◽  
Threshold Model ◽  
Operating Conditions ◽  
Quadratic Model ◽  
Modern World ◽  
Stochastic Effects ◽  
Radiation Accidents ◽  
Increased Risk

Introduction. Operation of radiation hazardous facilities is a reality of the modern world, and the future of the world economy is impossible without the development of nuclear and radiation technologies. At the same time, the widespread use of atomic energy puts forward an important and responsible task of ensuring the safety of the population and the environment in conditions of an increased risk of exposure to ionizing radiation and radioactive substances. In accordance with clause 3.2.1 of the "Radiation Safety Standards NRB-99/2009", the planned increased exposure of persons involved in emergency rescue operations related to the elimination of the consequences of radiation accidents is allowed for men, as a rule, over 30 years old only with their voluntary written consent, after informing about possible radiation doses and health risks. Increased exposure refers to exposure in excess of the basic dose limits under controlled (normal) operating conditions of radiation sources. Goals and objectives. The aim of the study is to increase the functionality of emergency services and fire and rescue subdivisions to perform tasks as intended in the elimination of radiation accidents. The tasks include the construction and substantiation of a model that allows converting the risks of deterministic effects into stochastic effects risks. Methods. When calculating the probability of output of stochastic and deterministic effects depending on the radiation dose and developing a threshold quadratic model, the least squares method and the probabilistic-statistical method were used. Results and discussion. The article shows that a linear non-threshold model of the interaction of radiation with matter greatly overestimates the risk of a stochastic effect emerging at doses of radiation. For example, this overestimation is 8,13 at a dose of D = 0,2 Sv/year. In this regard, a threshold quadratic model has been developed and proposed to be replaced by a threshold quadratic model, which makes it possible to increase the planned irradiation of personnel of emergency services and fire and rescue units during the elimination of radiation accidents in an effective dose from 0,2 Sv to 0,57 Sv, moreover, the probability of emergence of stochastic effects P2 = 0,0084 remains the same for both models. Conclusions. An increase in the maximum permissible dose of radiation for personnel of emergency services and fire and rescue units from 0,2 Sv/year to 0,5 Sv/year will make it possible to increase the functionality of the emergency services and fire and rescue units to perform tasks as intended by 2,5 times when elimination of radiation accidents. For example, the scope of rescue operations may be increased from 100 %, performed at a dose of D = 0,2 Sv/year, to 250 %, performed at a dose of D = 0,5 Sv/year. Key words: emergency services, fire and rescue units, radiation accidents, irradiation, linear no-threshold model, threshold quadratic model.

Downside risk asset pricing revisited: a new non-linear threshold model

2010 ◽  
Vol 13 (1) ◽  
pp. 129-159
Author(s):  
Jose Olmo
Keyword(s):  
Asset Pricing ◽  
Threshold Model ◽  
Downside Risk ◽  
Linear Threshold ◽  
Non Linear ◽  
Linear Threshold Model

A Threshold Model for Respondent Heterogeneity

2010 ◽  
Author(s):  
Sandeep R. Chandukala ◽  
S. Long-Tolbert ◽  
Greg M. Allenby
Keyword(s):  
Threshold Model
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