Genetic responses in the early years of selection programmes using genetic differences between generations

1979 ◽  
Vol 28 (1) ◽  
pp. 65-77 ◽  
Author(s):  
I. R. Hopkins ◽  
J. W. James
Keyword(s):  
Age Groups ◽  
Genetic Differences ◽  
Early Years ◽  
Economic Returns ◽  
Investment Appraisal ◽  
Multi Stage ◽  
Parent Selection ◽  
Group A ◽  
Definition Of ◽  
Genetic Responses

ABSTRACTRecurrence relationships are used to relate breeding values of age-sex classes from different time periods. Their application to single-stage (progeny) and multi-stage (parent) selection is demonstrated. These relationships enable definition of the effect of age structure, initial genetic differences between age groups, and the extent to which allowances are made for these or later genetic differences between age groups. The expressions derived show that, given initial genetic differences between age groups, subsequent progeny means will fluctuate even under completely random selection. Using these means as a basis for measuring responses to selection, it is shown that there can be selective effects where selection is at random within parental age classes. A careful definition of the alternative programme is therefore important in interpreting results of selection experiments and in investment appraisal of selection programmes.These models were then used to describe economic returns from parent and progeny selection programmes and from programmes in which returns are realized in more than one age group. A further extension of the model accommodates the effects of finite population size on returns through its effects on genetic variance.By separating the (constant) within- and (fluctuating) between-group components of the selection differential within the recurrence relationships a number of computational problems are overcome.

The effect of deviations from steady-state selection responses when generations overlap

1979 ◽  
Vol 28 (2) ◽  
pp. 139-148 ◽  
Author(s):  
I. R. Hopkins ◽  
J. W. James
Keyword(s):  
Steady State ◽  
Age Groups ◽  
Genetic Differences ◽  
Early Years ◽  
Economic Returns ◽  
Selection Responses ◽  
Starting Conditions ◽  
Steady State Responses ◽  
Definition Of ◽  
State Responses

ABSTRACTIn populations where generations overlap and initial genetic differences between age groups differ from steady-state values, genetic responses fluctuate in the early years of a selection programme. The degree of deviation of these selection responses from steady-state responses indicates the usefulness of estimates of economic returns calculated more simply using the steady-state value. Here these deviations and their effect on sums of discounted returns are first defined and the models derived then used in numerical analysis. Some problems of definition of these deviations are discussed.The results showed that deviations from sums of discounted returns calculated using steady-state responses varied from about −1% when starting conditions were similar to steady-state conditions to more than 20% when initial genetic differences between age groups were taken as zero. Increases in discount rate increased the effect of the deviations from uniform response while the effect of changing age structure was unpredictable. As initial genetic differences between age groups increased, deviations were increasingly positive among selection methods which made better use of those differences.

Dynamic and static selection policies when generations overlap

1979 ◽  
Vol 28 (2) ◽  
pp. 149-155
Author(s):  
I. R. Hopkins
Keyword(s):  
Age Groups ◽  
Genetic Differences ◽  
Discount Rates ◽  
Dynamic Selection ◽  
Selection Policy ◽  
Large Numbers ◽  
Dynamic Policy ◽  
Selection Policies ◽  
Genetic Responses ◽  
Genetic Contributions

ABSTRACTWhere genetic differences between age groups change during a selection programme, proportional contributions of each age group to replacements should also change in order to maximize genetic responses to selection. Sums of discounted returns were estimated for such a ‘dynamic’ selection policy and these were compared with those from ‘static’ selection policies in which genetic contributions of different age groups remained unchanged. Four selection methods, two sets of genetic differences between age groups at the outset, three age structures and two discount rates were used.The results showed that the superiority of the dynamic policy was greatest where genetic differences at the outset differed most markedly from their steady-state values, where discount rates are high and where there are large numbers of age groups and the selection method allows culling in all age groups. Under most conditions initial genetic differences are probably the most important factor. The proportional advantage in sums of discounted returns is variable and generally small within the framework of this study ranging from zero to roughly 8% unless breeding objectives before and during the programme were negatively correlated. In the latter case the proportional superiority of the dynamic policy was much greater.

Some optimum selection strategies and age structures with overlapping generations

1977 ◽  
Vol 25 (2) ◽  
pp. 111-132 ◽  
Author(s):  
I. R. Hopkins ◽  
J. W. James
Keyword(s):  
Age Groups ◽  
Breeding Population ◽  
Breeding Value ◽  
Relative Advantage ◽  
Male Mating ◽  
Genetic Response ◽  
Selection Strategies ◽  
Parent Selection ◽  
Breeding Herd ◽  
Genetic Responses

SUMMARYGenetic responses from selection strategies based on selection among all potential parents of the following year's crop were compared with those based on selection only within progeny crops. In the former group of strategies the duration of stay of an individual in the breeding herd is determined by the estimated breeding value of that individual, whereas in the classic model selected individuals of the same sex all remain in the breeding population for the same period. The former group of strategies, termed ‘parent selection’ strategies, were consistently superior in genetic response to the progeny selection strategies with a very large relative advantage under some conditions. The superiority of strategies that make more efficient use of genetic differences between own or parental age was greater among parent selection strategies than among progeny selection strategies. Similarly, increases in female to male mating ratios, fertility and survival rate generally resulted in larger increases i n genetic response in the more efficient strategies. The effect of changes in number of male and female age groups differs markedly between strategies.

Hypercoagulable State in the Watanabe Heritable Hyperlipidemic Rabbit, an Animal Model for the Progression of Atherosclerosis

1989 ◽  
Vol 61 (01) ◽  
pp. 140-143 ◽  
Author(s):  
Yoshitaka Mori ◽  
Hideo Wada ◽  
Yutaka Nagano ◽  
Katsumi Deguch ◽  
Toru Kita ◽  
...  
Keyword(s):  
Vitamin K ◽  
Fibrinogen Level ◽  
Plasma Cholesterol ◽  
Age Groups ◽  
Clotting Factor ◽  
Clotting Factors ◽  
Group A ◽  
Hyperlipidemic Rabbit ◽  
Group B ◽  
Progression Of Atherosclerosis

SummaryBlood coagulation in a strain of rabbits designated as Watanabe heritable hyperlipidemic (WHHL) rabbits was examined. The activities of vitamin K-dependent clotting factors, contact factors and clotting factor VIII (F VIII) and the fibrinogen level were significantly higher in WHHL rabbits than in normolipidemic rabbits (all age groups). Values for vitamin Independent clotting factor were already higher at 2 months of age. Contact factors and fibrinogen levels increased age after 5 to 8 months. F VIII increased between 5 and 8 months and then decreased. At 2 months of age, WHHL rabbits were divided into two groups. Group A was fed standard rabbit chow and group B standard rabbit chow containing 1% probucol. Probucol prevented the progression of atherosclerosis in group B in the absence of a significant reduction in plasma cholesterol level. F VIII and fibrinogen levels were statistically decreased in all rabbits at all ages in group B (P<0.05). These differences in clotting factors between the two groups were most obvious at 8 months (P<0.02).We conclude that vitamin K-dependent clotting factors may increase with hyperlipemia and that increases in F VIII and fibrinogen may be closely related to the progression of throm- boatherosclerosis.

Age related volume of cadaver-prostates in Bangladesh

1970 ◽  
Vol 4 (2) ◽  
pp. 74-77
Author(s):  
Rukshana Ahmed ◽  
Shamim Ara
Keyword(s):  
Prostate Gland ◽  
Age Groups ◽  
Clinical Settings ◽  
Cross Sectional ◽  
Medical College ◽  
Age Related ◽  
Group A ◽  
Key Words Prostate ◽  
The Mean ◽  
Group B

Pathological changes in the prostate gland occur commonly with advancing age including inflammation, atrophy, hyperplasia and carcinoma and a change in volume is also evident. Estimation of volume of prostate may be useful in a variety of clinical settings. A cross-sectional descriptive study was designed to see the changes in volume of the prostate with advancing age and done in the Department of Anatomy, Dhaka Medical College, Dhaka from August 2006 to June 2007. The study was performed on 70 post-mortem human prostates collected from the unclaimed dead bodies that were under examination in the Department of Forensic Medicine, Dhaka Medical College, Dhaka. The samples were divided into three age groups; group A (10-20 years), group B (21-40 years) and group C (41-70 years). Volume of the sample was measured by using the ellipsoid formula. The mean ± SD volume of prostate was 7.68 ± 3.64 cm3 in group A, 10.61 ± 3.99 cm3 in group B and 15.40 ± 6.31 cm3 in group C. Mean difference in volume between group A and group C, group B and group C were statistically significant (p<0.001). Statistically significant positive correlation was found between age and volume of prostate (r = + 0.579, p < 0.001). Key Words: Prostate; volume; Bangladeshi. DOI: 10.3329/imcj.v4i2.6501Ibrahim Med. Coll. J. 2010; 4(2): 74-77

Histological Study of Human Thyroid Gland Relative Proportion of Parenchyma and Stroma in Thyroid Glands of Bangladeshi People

2013 ◽  
Vol 1 (2) ◽  
pp. 17-20
Author(s):  
Md Enayet Ullah ◽  
Hasna Hena ◽  
Rubina Qasim
Keyword(s):  
Thyroid Gland ◽  
Histological Study ◽  
Relative Proportion ◽  
Age Groups ◽  
Human Thyroid ◽  
Structural Units ◽  
Thyroid Glands ◽  
Group A ◽  
Group B ◽  
Connective Tissue Sheath

Deep cervical fascia forms a connective tissue sheath around the thyroid gland. Delicate trabeculae and septa penetrate the gland indistinctly dividing the gland into lobes and lobules which in turn composed of follicles.1,2,3 These follicles are structural units of thyroid gland which varies greatly in size and shape.4 The number of follicles varies in different age groups. The study was carried out to see the percentage of area occupied by follicles in the stained section of thyroid glands in different age groups. The collected samples were grouped as A (3.5 – 20yrs), B (21- 40yrs) & C (41 – 78yrs). Percentage of area occupied by follicles was (58.55±10.72) in group A, (63.79±12.35) in group B + (63.39±8.29) in group C.DOI: http://dx.doi.org/10.3329/updcj.v1i2.13981 Update Dent. Coll. j. 2011: 1(2): 17-20

scholarly journals Validity of the Gender Dysphoria diagnosis and incidence trends in Sweden: a nationwide register study

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Malin Indremo ◽  
Richard White ◽  
Thomas Frisell ◽  
Sven Cnattingius ◽  
Alkistis Skalkidou ◽  
...  
Keyword(s):  
Gender Dysphoria ◽  
Age Groups ◽  
Medical Intervention ◽  
Future Research ◽  
Advantages And Disadvantages ◽  
Incidence Trends ◽  
Interaction Terms ◽  
Definition Of ◽  
The Individual ◽  
Nationwide Register Study

AbstractThe aim of this study was to examine the validity of the Gender Dysphoria (GD) diagnoses in the Swedish National Patient Register (NPR), to discuss different register-based definitions of GD and to investigate incidence trends. We collected data on all individuals with registered GD diagnoses between 2001 and 2016 as well as data on the coverage in the NPR. We regarded gender confirming medical intervention (GCMI) as one proxy for a clinically valid diagnosis and calculated the positive predictive value (PPV) for receiving GCMI for increasing number of registered GD diagnoses. We assessed crude and coverage-adjusted time trends of GD during 2004–2015 with a Poisson regression, using assigned sex and age as interaction terms. The PPV for receiving GCMI was 68% for ≥ 1 and 79% for ≥ 4 GD-diagnoses. The incidence of GD was on average 35% higher with the definition of ≥ 1 compared to the definition of ≥ 4 diagnoses. The incidence of GD, defined as ≥ 4 diagnoses increased significantly during the study period and mostly in the age categories 10–17 and 18–30 years, even after adjusting for register coverage. We concluded that the validity of a single ICD code denoting clinical GD in the Swedish NPR can be questioned. For future research, we propose to carefully weight the advantages and disadvantages of different register-based definitions according to the individual study’s needs, the time periods involved and the age-groups under study.

scholarly journals Review of Studies on Older Drivers’ Behavior and Stress—Methods, Results, and Outlook

Sensors ◽  
2021 ◽  
Vol 21 (10) ◽  
pp. 3503
Author(s):  
Yanning Zhao ◽  
Toshiyuki Yamamoto
Keyword(s):  
Age Groups ◽  
Older Drivers ◽  
Driving Simulators ◽  
Driving Experience ◽  
Older Driver ◽  
Vehicle Data ◽  
Vehicle Systems ◽  
Questionnaire Surveys ◽  
Definition Of ◽  
Short Time

This paper presents a review on relevant studies and reports related to older drivers’ behavior and stress. Questionnaires, simulators, and on-road/in-vehicle systems are used to collect driving data in most studies. In addition, research either directly compares older drivers and the other drivers or considers participants according to various age groups. Nevertheless, the definition of ‘older driver’ varies not only across studies but also across different government reports. Although questionnaire surveys are widely used to affordably obtain massive data in a short time, they lack objectivity. In contrast, biomedical information can increase the reliability of a driving stress assessment when collected in environments such as driving simulators and on-road experiments. Various studies determined that driving behavior and stress remain stable regardless of age, whereas others reported degradation of driving abilities and increased driving stress among older drivers. Instead of age, many researchers recommended considering other influencing factors, such as gender, living area, and driving experience. To mitigate bias in findings, this literature review suggests a hybrid method by applying surveys and collecting on-road/in-vehicle data.

Food intake, physical activity and quality of life among children and youth

Work ◽  
2021 ◽  
pp. 1-10
Author(s):  
Emília Martins ◽  
Rosina Fernandes ◽  
Francisco Mendes ◽  
Cátia Magalhães ◽  
Patrícia Araújo
Keyword(s):  
Quality Of Life ◽  
Physical Activity ◽  
Healthy Lifestyle ◽  
Eating Habits ◽  
Age Groups ◽  
Related Quality ◽  
Health Related ◽  
Life Habits ◽  
Definition Of

BACKGROUND: The health-related quality of life construct (QoL) implies a relationship with eating habits (EA) and physical activity (PA). Sociodemographic and anthropometric variables (gender, age and Body Mass Index - BMI) are highlighted in the definition of healthy lifestyle habits promotion strategies. OBJECTIVE: We aim to characterize and relate PA, EA and QoL in children/youth and explore gender, age and BMI influences. METHODS: It is a non-experimental study, with 337 children/youth, ages between 8 and 17 years (12.61±2.96), mostly from the rural inland of Portugal. In data collection we used a sociodemographic and anthropometric questionnaire, a weekly register table of EA and Kid-Kindl (QoL). Statistical analysis (p <  0.05) were performed in SPSS-IBM 25. RESULTS: Lower BMI was associated with better EA (p <  0.001), PA (p <  0.05) and self-esteem (p <  0.01) and worse scores on family subscale of QoL. Female showed higher fruit intake (p <  0.05). The older has shown better results. PA is positively correlated with QoL (p <  0.01) and EA (p <  0.05). CONCLUSIONS: It is important to explore other relevant social and family dimensions, to promote intervention programs with parents, school and community, as well as healthy practices policies. The intervention in these age groups is critical for a longer-term impact in improving healthy life habits.

scholarly journals Comparison of Prevalence of Periodontitis with Different Indices in Population of District Ghaziabad

2016 ◽  
Vol 04 (01) ◽  
pp. 023-030
Author(s):  
Vimal Kumar ◽  
Pallak Arora ◽  
Manish Khatri ◽  
Shivani Sharma ◽  
Sumit Malhotra ◽  
...  
Keyword(s):  
Periodontal Disease ◽  
Total Population ◽  
Age Groups ◽  
Cross Sectional Study ◽  
Sample Population ◽  
Age Group ◽  
Cross Sectional ◽  
Multi Stage ◽  
Younger Age ◽  
Study Population

Abstract Objective: To estimate the prevalence of periodontal disease with different indices. Methods & materials: The study population consisted of multistage stratified random sample of 1300 subjects from total population of district Ghaziabad. A cross-sectional study was conducted with multi stage stratified random sampling techniques to select the sample population. The subjects were divided into different age groups and the periodontal assessment was made on the basis of CPITN index and ESI Index. Results: The CPITN has shown to estimate incorrect periodontal disease prevalence because of its underestimation of the disease severity. A huge difference was noticed in the prevalence rate of periodontitis when subjects were examined with ESI index. Conclusion Periodontal disease was found to be highly prevalent in the study population and severity of disease increased with age. More number of subjects in younger age group were found to be healthy.

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