scholarly journals Genealogical distances under low levels of selection

2018 ◽  
Author(s):  
Elisabeth Huss ◽  
Peter Pfaffelhuber
Keyword(s):  
Population Sample ◽  
Levels Of Selection ◽  
Selection Intensity ◽  
Constant Size ◽  
Tree Length ◽  
Analytic Expression ◽  
Low Levels ◽  
The Difference ◽  
Total Tree ◽  
Kingman’S Coalescent

AbstractFor a panmictic population of constant size evolving under neutrality, Kingman’s coalescent describes the genealogy of a population sample in equilibrium. However, for genealogical trees under selection, not even expectations for most basic quantities like height and length of the resulting random tree are known. Here, we give an analytic expression for the distribution of the total tree length of a sample of size n under low levels of selection in a two-alleles model. We can prove that trees are shorter than under neutrality under genic selection and if the beneficial mutant has dominance h < 1/2, but longer for h > 1/2. The difference from neutrality is 𝒪 (α2) for genic selection with selection intensity α and 𝒪 (α) for other modes of dominance.

scholarly journals Gene Genealogies Within Mutant Allelic Classes

Genetics ◽  
1996 ◽  
Vol 143 (1) ◽  
pp. 579-587 ◽  
Author(s):  
Montgomery Slatkin
Keyword(s):  
Sequence Data ◽  
Pairwise Distance ◽  
Mutational Event ◽  
Nucleotide Sequence Data ◽  
Gene Genealogy ◽  
Constant Size ◽  
Stepwise Mutation ◽  
Tree Length ◽  
Infinite Sites Model ◽  
Total Tree

Abstract A coalescent theory of the gene genealogy within an allelic class that arises by a unique mutational event is developed and analyzed. To interpret this theory it was necessary to expand on existing theory for populations of varying size. Two features of the gene genealogy—the average pairwise distance and the total tree length—within the mutant class and within the nonmutant class are found. An index, I, is proposed that describes the extent to which a genealogy is similar to one from a population of constant size (for which I = 0) or to a star genealogy (for which I = 1). The value of I is positive in growing populations and is generally positive for the gene genealogy for the mutant class. The value of lis negative for a population decreasing in size and for the nonmutant class, if the mutant arose recently. The results are discussed in the context of the infinite sites model of mutation, which is appropriate for nucleotide sequence data, and the generalized stepwise mutation model, which is appropriate for microsatellite loci. The same genealogical methods are used to find the probability of at least one recombination event between a nucleotide that defines an allelic class and a marker at a nearby linked site.

INHERITED FACTOR-VII DEFECT IN A NEGRO FAMILY

PEDIATRICS ◽  
1961 ◽  
Vol 27 (2) ◽  
pp. 204-213
Author(s):  
Helen I. Glueck ◽  
James M. Sutherland
Keyword(s):  
Prothrombin Time ◽  
Factor Vii ◽  
Homozygous State ◽  
Control Value ◽  
One Stage ◽  
First Case ◽  
Severe Deficiency ◽  
Low Levels ◽  
The Difference ◽  
The One

A case of factor-VII deficiency of a congenital nature in a Negro male child has been reported. As far as can be determined, this is the first case reported in this race. The defect was detected at 6 hours of age. Prothrombin, as contrasted to factor VII, after initially low levels normally found in infants, rose to adult levels. The patient's one-stage prothrombin time has ranged between 25 to 35 second (normal 11 to 12 seconds). In spite of this, he has never shown any manifestations of hemorrhage. The patient's family was studied and the findings indicate that the patient's defect represented a homozygous state and that both parents with a less severe deficiency were heterozygous for the trait. The defect is an autosomal disorder directly inherited. It is clinically apparent and easily detected only in the homozygous state. The heterozygous state is characterized by a very slight prolongation of the one-stage prothrombin time, the difference from the control value being so minimal as to be overlooked. In one subject studied, an aunt of the propositus, the quantitative defect (42% of normal) could not be regularly detected by the usual methods. Only by using the plasma of the propositus as the test plasma, was the defect in her plasma detected, thus explaining the transmission of the trait to her offspring. These findings explain the difficulties previously encountered in understanding the inheritance of the disorder.

The economic and financial viability of sheltered employment centres

2019 ◽  
Vol 57 (9) ◽  
pp. 2261-2283
Author(s):  
Vera Gelashvili ◽  
Eva María Aguilar Pastor ◽  
María-Jesús Segovia-Vargas ◽  
Maria-del-Mar Camacho-Miñano
Keyword(s):  
Training Programs ◽  
Similar Response ◽  
Economic Returns ◽  
Content Type ◽  
Strategic Plans ◽  
Low Levels ◽  
The Difference ◽  
Practical Implications ◽  
Very High

Purpose The purpose of this paper is to investigate whether sheltered employment centers (CEEs) which have a higher rate of professionalization of their managers have better economic returns than those that have a lower one. Design/methodology/approach A questionnaire has been drawn up for their managers. After collecting the answers, an index of professionalization classifies the CEEs with managers of high, medium and low levels of professionalism. This index is then correlated with the main financial ratios of companies. Findings The results show that companies with the highest level of managers’ professionalization, on average, have higher economic returns than companies with medium and low rates, although the difference is not very high. This study is an important contribution to academic literature, as it is the first to examine the professionalization of CEE managers. Research limitations/implications Finally, this paper is not short of limitations. The number of responses is small but there are similar studies with similar response rates. Additionally, the scarcity of responses may suggest that there is a lack of interest about the utility of professionalization by some CEEs managers because, perhaps, they do not have the necessary competences to understand its importance in management. Practical implications This study has some main implications for stakeholders: first, CEEs must pay more attention to the professionalization of their management team, because professionalization can lead to meeting its goals and guaranteeing the firm’s growth. Second, training programs in skills and attitudes should be designed to strengthen these competencies. Moreover, managers of social firms should know that the establishment of strategic plans will be useful to identify new opportunities in the market. Social implications Given the important role of these social firms for the employment of people with disabilities, training programs should be promoted by government in order to ensure the professionalization of these companies. Originality/value This research is an important contribution to the literature on this subject because there are no studies about the level of professionalization of CEEs, companies that represent an important value for the economy of a country.

scholarly journals Genetic causes of reproductive problems in the Bosnian women population

2018 ◽  
Vol 9 (5) ◽  
pp. 12-16
Author(s):  
Mirela Mackic-Djurovic ◽  
Dunja Rukavina ◽  
Lejla Ahmetas
Keyword(s):  
Chromosomal Aberrations ◽  
Genetic Factors ◽  
Chromosomal Abnormalities ◽  
Population Sample ◽  
Medical Sciences ◽  
Abnormal Karyotype ◽  
Female Population ◽  
Reproductive Disorder ◽  
The Difference ◽  
Bosnian Women

Background: The causes of infertility and recurrent spontaneous abortions are diverse and numerous – including non-genetic and genetic factors – whereby the importance of genetic factors in pathogenesis of infertility is becoming more and more common. Chromosomal abnormalities and genetic defects can cause reproduction failures, and for this reason genetic analysis can play an important role in reproductive problems research.Aims and Objective: This study aims to determine the type and frequency of chromosomalaberrations in the female population sample, as well as to determine if the difference between groups with and without chromosomal aberrations was statistically significant.Materials and Methods: One hundred women aged 15-46 were included in the study, allhaving different reproductive disorder diagnoses and requiring karyotype analysis in the Sarajevo Medical Faculty Genetic Center. Cytogenetic analysis was performed on the peripheral blood, which was cultured for four days, using GTG banding forchromosomalanalysis.Results: Out of 100 women included in the study, an abnormal karyotype was found in 16 of them (16%). The difference between the frequency of normal and abnormal karyotype in women with reproductive problems identified in this study was found to be statistically significant. The pattern of chromosomal aberrations was similar to that reported in the previous cytogenetic studies with similar inclusion criteria.Conclusion: This fact should be taken in the consideration in order to estimate true etiology of reproductive problems and it is a valuable information in the process of genetic counseling and decision making in assisted reproductive technology.Asian Journal of Medical Sciences Vol.9(5) 2018 12-16

EFFECTS OF CONTINUOUS DAILY ADMINISTRATION OF 0.5 mg OF CHLORMADINONE ACETATE ON THE PLASMA LEVELS OF PROGESTERONE AND ON THE URINARY EXCRETION OF LUTEINIZING HORMONE AND TOTAL OESTROGENS

1970 ◽  
Vol 63 (4) ◽  
pp. 705-716 ◽  
Author(s):  
U. Larsson-Cohn ◽  
E. D. B. Johansson ◽  
L. Wide ◽  
C. Gemzell
Keyword(s):  
Luteinizing Hormone ◽  
Plasma Level ◽  
Urinary Excretion ◽  
Corpus Luteum ◽  
Plasma Levels ◽  
Chlormadinone Acetate ◽  
The Mean ◽  
Low Levels ◽  
The Difference ◽  
All Treatment

ABSTRACT Daily determinations of the plasma level of progesterone and the urinary excretion of luteinizing hormone (LH) and total oestrogens were performed in 6 subjects during one control cycle, immediately followed by three cycles of daily treatment with 0.5 mg of chlormadinone acetate continuously. The control cycles were ovulatory according to the parameters investigated. Two of the women showed a normal LH excretion pattern in all treatment cycles. The four other subjects also had periodical variations in the LH excretion but no distinct midcycle peaks occurred. The mean oestrogen excretion was increased in all three treatment cycles but the difference was satistically significant only in the last two cycles. Compared with the treatment cycles, the sum of progesterone values was significantly decreased in the first two cycles. Chlormadinone acetate in this dose had no thermogenic effect. Three of the subjects showed bleeding irregularities which had no clear connection with the hormone variations measured in the study. It is suggested that the low levels of progesterone might be due to a defective corpus luteum function.

Mycotoxins in organically versus conventionally produced cereal grains and some other crops in temperate regions

2016 ◽  
Vol 9 (5) ◽  
pp. 755-770 ◽  
Author(s):  
G. Brodal ◽  
I.S. Hofgaard ◽  
G.S. Eriksen ◽  
A. Bernhoft ◽  
L. Sundheim
Keyword(s):  
Farming Systems ◽  
Weather Conditions ◽  
Field Trials ◽  
Cereal Grains ◽  
Organic System ◽  
Mycotoxin Contamination ◽  
Significant Difference ◽  
Apple Products ◽  
Low Levels ◽  
The Difference

This paper presents peer-reviewed studies comparing the content of deoxynivalenol (DON), HT-2+T-2 toxins, zearalenone (ZEA), nivalenol (NIV), ochratoxin A (OTA) and fumonisins in cereal grains, and patulin (PAT) in apple and apple-based products, produced in organically and conventionally grown crops in temperate regions. Some of the studies are based on data from controlled field trials, however, most are farm surveys and some are food basket surveys. Almost half of the studies focused on DON in cereals. The majority of these studies found no significant difference in DON content in grain from the two farming systems, but several studies showed lower DON content in organically than in conventionally produced cereals. A number of the investigations reported low DON levels in grain, far below the EU limits for food. Many authors suggested that weather conditions, years, locations, tillage practice and crop rotation are more important for the development of DON than the type of farming. Organically produced oats contained mainly lower levels of HT-2+T-2 toxins than conventionally produced oats. Most studies on ZEA reported no differences between farming systems, or lower concentrations in organically produced grain. For the other mycotoxins in cereals, mainly low levels and no differences between the two farming systems were reported. Some studies showed higher PAT contamination in organically than in conventionally produced apple and apple products. The difference may be due to more efficient disease control in conventional orchards. It cannot be concluded that any of the two farming systems increases the risk of mycotoxin contamination. Despite no use of fungicides, an organic system appears generally able to maintain mycotoxin contamination at low levels. More systematic comparisons from scientifically controlled field trials and surveys are needed to clarify if there are differences in the risk of mycotoxin contamination between organically and conventionally produced crops.

Adaptation and Natural Selection

2021 ◽  
pp. 125-154
Author(s):  
Áki J. Láruson ◽  
Floyd A. Reed
Keyword(s):  
Natural Selection ◽  
Allele Frequency ◽  
Levels Of Selection ◽  
Frequency Data ◽  
Selection Coefficient ◽  
Frequency Distributions ◽  
Single Allele ◽  
Selection Strength ◽  
The Difference ◽  
Over Time

Here non-random shifts in allele frequencies over time are introduced, as well as how to incorporate varying levels of selection into a model of a single population through time. This chapter highlights the difference between weak and strong selection, the dynamics of single allele versus genotype-level selection, and how selection strength and population size affect allele frequency distributions over time. Finally the inference of the selection coefficient from allele frequency data is discussed, alongside the concepts of overdominance and underdominance.

Socioeconomic and gender inequalities in neonatal, postneonatal and child mortality in India: a repeated cross-sectional study, 2005–2016

2019 ◽  
Vol 73 (7) ◽  
pp. 660-667
Author(s):  
Omar Karlsson ◽  
Rockli Kim ◽  
William Joe ◽  
S V Subramanian
Keyword(s):  
Neonatal Mortality ◽  
Child Mortality ◽  
Gender Gap ◽  
Cross Sectional Study ◽  
North India ◽  
Gender Inequalities ◽  
Sectional Study ◽  
Cross Sectional ◽  
Low Levels ◽  
The Difference

BackgroundIn India, excess female under-5 mortality is well documented. Under-5 mortality is also known to be patterned by socioeconomic factors. This study examines sex differentials and sex-specific wealth gradients in neonatal, postneonatal and child mortality in India.MethodsRepeated cross-sectional study of nationally representative samples of 298 955 children 0–60 months old from the National Family Health Surveys conducted in 2005–2006 and 2015–2016. The study used logistic regression models as well as Cox proportional hazards models.ResultsOverall, boys had greater neonatal mortality than girls and the difference increased between 2005–2006 and 2015–2016. Girls had greater postneonatal and child mortality, but the difference decreased between the surveys and was not statistically significant for child mortality in 2015–2016. A negative wealth gradient was found for all mortality outcomes. Neonatal mortality was persistently greater for boys. Girls had higher child mortality than boys at low levels of wealth and greater postneonatal mortality over much of the wealth distribution. The wealth gradient in neonatal mortality increased between surveys. Females had a stronger wealth gradient than boys for child mortality.ConclusionNot distinguishing between neonatal, postneonatal and child mortality masks important gender-specific and wealth-specific disparities in under-5 mortality in India. Substantial gains towards the Sustainable Development Goals can be made by combating neonatal mortality, especially at low levels of wealth. Although impressive improvements have been made in reducing the female disadvantage in postneonatal and child mortality, concerted engagements are necessary to eliminate the gender gap—especially in poor households and in north India.

The influence of selection and plane of nutrition on the components of fleece weight in Merino sheep

1958 ◽  
Vol 9 (6) ◽  
pp. 802 ◽  
Author(s):  
RB Dun
Keyword(s):  
Fibre Diameter ◽  
Fibre Length ◽  
Small Contribution ◽  
Cross Sectional ◽  
Single Character ◽  
The Mean ◽  
Low Levels ◽  
The Difference ◽  
Fleece Weight ◽  
High Level

The components of clean fleece weight were examined in five experimental flocks of medium-wool Peppin Merinos. Four single-character selection groups – clean fleece weight plus, clean fleece weight minus, crimps per inch plus, and crimps per inch minus – were examined by measuring fleece production in 18-month-old ewe progeny. Measurements were also made on progeny from the "nucleus" flock, which was selected for clean fleece weight with subsidiary selection for crimps per inch and against fold score. Data were collected in 1952 and 1954. The 1954 figures were obtained from a nutrition experiment in which sheep mere grown from weaning to 18 months on a high and on a low plane of nutrition. The mean measurements of the components of clean fleece weight (W) were compared between flocks using the "percentage deviation" technique. Four comparisons were made: (1) Nucleus/Fleece minus; (2) Fleece plus/Fleece minus; (3) Crimps minus/Crimps plus; (4) high nutritional plane/low nutritional plane. In comparisons (1) , (2), and (3), difference in weight of wool per unit area of skin (w) accounted for nearly all the difference in W. Body weight (S) made a small contribution while difference in fold score (R) was negligible. Fibre density (N) accounted for +86 per cent., and fibre cross-sectional area (A) for –28 per cent., of the difference in W in comparison (1). In comparison (2) the figures were N +47 per cent., A +21 per cent., while the figures for comparison (3) were N –26 per cent., A +121 per cent. The increase in fleece weight was invariably accompanied by a decrease in crimps per inch. In all three comparisons primary density (P) was the major cause of change in N. Fibre length (L) made a uniform contribution of approximately +15 per cent. in the three comparisons.The relative importance of the components of fleece weight was similar at both high and low levels of nutrition.The effect of a high level of nutrition was to produce large increases in A, L, and S. The increase in S was compensated by an equal decrease in P. The increase in fibre diameter was not associated with any change in crimps per inch.

Effect of cooling of orbital cortex on exercise hyperpnea in the dog

1959 ◽  
Vol 14 (2) ◽  
pp. 241-244 ◽  
Author(s):  
John P. Henry ◽  
W. V. Whitehorn
Keyword(s):  
Minute Volume ◽  
Orbital Cortex ◽  
Hind Limbs ◽  
Exercise Hyperpnea ◽  
Anesthetized Dogs ◽  
Low Levels ◽  
The Difference ◽  
Ventilatory Volume ◽  
Respiratory Area

The significance of cortical contribution to the hyperpnea of exercise has long been debated. An attempt was made to evaluate the role of this factor by cooling the respiratory area of the orbital cortex in 20 experiments on 13 Nembutal-urethane anesthetized dogs before, during and after electrically induced exercise of the hind limbs. Orbital cooling during eupnea produced a 10% decrease in respiratory rate with questionable reduction of minute volume. Cooling induced during exercise resulted in reduction of mean ventilatory volume from 4.37 l/min. to 4.18 l/min. The difference is highly significant statistically and represents 20% of the exercise hyperpnea under these conditions. Cessation of cooling was followed by return to precooling levels. Results indicate that cortical impulses contribute to exercise hyperpnea even under conditions of anesthesia and low levels of exercise and suggest a quantitative approach to evaluation of this factor under more physiologic conditions. Submitted on July 21, 1958

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