Multiplicative vs. arbitrary gene action in heterosis.

Genetics ◽  
1992 ◽  
Vol 131 (2) ◽  
pp. 461-469 ◽  
Author(s):  
F W Schnell ◽  
C C Cockerham
Keyword(s):  
Gene Action ◽  
Extensive Literature ◽  
Additive Effects ◽  
Nonlinear Functions ◽  
Epistatic Effects ◽  
Genetic Significance ◽  
The Mean ◽  
The Difference ◽  
Multiplicative Models ◽  
Multiplicative Effects

Abstract In this article we investigate multiplicative effects between genes in relation to heterosis. The extensive literature on heterosis due to multiplicative effects between characters is reviewed, as is earlier work on the genetic description of heterosis. A two-locus diallelic model of arbitrary gene action is used to derive linear parameters for two multiplicative models. With multiplicative action between loci, epistatic effects are nonlinear functions of one-locus effects and the mean. With completely multiplicative action, the mean and additive effects form similar restrictions for all the rest of the effects. Extensions to more than two loci are indicated. The linear parameters of various models are then used to describe heterosis, which is taken as the difference between respective averages of a cross (F1) and its two parent populations (P). The difference (F2 - P) is also discussed. Two parts of heterosis are distinguished: part I arising from dominance, and part II due to additive x additive (a x a)-epistasis. Heterosis with multiplicative action between loci implies multiplicative accumulation of heterosis present at individual loci in part I, in addition to multiplicative (a x a)-interaction in part II. Heterosis with completely multiplicative action can only be negative (i.e., the F1 values must be less than the midparent), but the difference (F2 - P) can be positive under certain conditions. Heterosis without dominance can arise from multiplicative as well as any other nonadditive action between loci, as is exemplified by diminishing return interaction. The discussion enlarges the scope in various directions: the genetic significance of multiplicative models is considered.(ABSTRACT TRUNCATED AT 250 WORDS)

Genetic variability for resistance to trifluralin inZea mays

Weed Science ◽  
1999 ◽  
Vol 47 (4) ◽  
pp. 369-374 ◽  
Author(s):  
Pierangelo Landi ◽  
Elisabetta Frascaroli ◽  
Marcella M. Giuliani
Keyword(s):  
Genetic Variability ◽  
Lipid Content ◽  
Field Data ◽  
Seed Lipid ◽  
Reciprocal Effects ◽  
Additive Effects ◽  
Resistance Level ◽  
The Mean ◽  
The Difference ◽  
Nonadditive Effects

Soil carryover of the herbicide trifluralin can injureZea mays.Therefore, the development of resistant hybrids can be an important breeding objective. This research was conducted to study the genetic variability for trifluralin resistance inZ. mays, the effects of genes controlling resistance, and the seed lipid content of resistant (R) and susceptible (S) inbreds. Twenty inbreds were tested under greenhouse conditions at three trifluralin rates (0, 12.5, and 125 g ai ha−1). Lo1067 was the most resistant, and A632 was the most susceptible inbred. Hybrids among R and S inbreds were tested, along with their parents, under greenhouse conditions (using the same three rates) and in the field (at 0, 0.4, and 0.8 kg ai ha−1). Under both greenhouse and field conditions, inbreds R were more resistant than S. Hybrids R × R were more resistant than S × S, indicating that additive effects were important. Hybrids R × S and S × R did not significantly differ, indicating that reciprocal effects were not important. On average, hybrids R × S and S × R were intermediate between R × R and S × S, suggesting that nonadditive effects were negligible. The difference between the mean across hybrids and the mean across parents (further estimating the importance of nonadditive effects) was significant only for parameters investigated in the greenhouse. Greenhouse data were correlated with field data, but the coefficients of determination were < 50%. The ability to predict hybrid resistance on the basis of parental mean was higher in the greenhouse (r2= 0.78) than in the field (r2= 0.47). R and S inbreds also differed in seed lipid content, but correlations were negligible with greenhouse and field data. Data indicated the presence of genetic variability for trifluralin resistance, that additive effects were prevailing, and that the resistance level was not related to seed lipid content.

Analysis of pest resistance in alfalfa with a new autotetraploid genetic model

1985 ◽  
Vol 27 (1) ◽  
pp. 39-46 ◽  
Author(s):  
R. R. Hill Jr. ◽  
J. H. Elgin Jr.
Keyword(s):  
Population Genetics ◽  
Gene Action ◽  
Genetic Model ◽  
Pest Resistance ◽  
Additive Effects ◽  
Approach To Equilibrium ◽  
Parent Population ◽  
Medicago Sativa L ◽  
The Mean ◽  
Resistance Data

A genetic model for the analysis of crosses and advanced generations between autotetraploid populations had been developed and applied to an analysis of pest resistance data in an experiment on alfalfa (Medicago sativa L.). The model had the form [Formula: see text] where [Formula: see text] is the observed mean of combination ij in generation n, C is a constant, u, is a parameter for the mean of parent population i, kn and mn are constants computed from the theoretical approach to equilibrium in the population, Gij is the digenic parameter in the equilibrium population that would arise from the population cross, and Qij is the quadrigenic parameter for that population. Nonadditive genetic effects were observed for most of the traits subjected to analysis under the model. The mode of gene action varied from one population to another in many cases. Variances of estimates of Gij were small, but those of Qij were very large. The large covariance between estimates of Gij and Qij was caused by a correlation between coefficients of these parameters.Key words: pest resistance, Medicago, autotetraploid, additive effects, population genetics.

scholarly journals Effects of milk protein loci on content of their proteins

2003 ◽  
Vol 46 (4) ◽  
pp. 331-340 ◽  
Author(s):  
R. Graml ◽  
F. Pirchner
Keyword(s):  
Milk Protein ◽  
Genetic Variance ◽  
Gene Action ◽  
Milk Proteins ◽  
Brown Swiss ◽  
Allele Specific ◽  
Locus Allele ◽  
The Mean ◽  
The Difference ◽  
One Year

Abstract. Allele specific milk proteins were measured in 4544 samples from 2054 Fleckvieh (FV) cows in two succeeding years and in one year from 1809 Braunvieh (BV) cows partly crossbreds with Brown Swiss. The cows were from 454 and 403 sires, and in 316 and 46 farms, respectively. The allele specific milk proteins were measured photometrically. Gene action was mainly additive, but the aS1-CN BC was 2 to 4 % above the mean of the homozygotes and the heterozygotes at the CSN2 locus deviated from –2 to + 8 % from the means of the respective homozygotes. The extent of expression of the alleles varied. At CSN1S1 higher expression was shown by the B alleles in heterozygotes, and by the C alleles in homozygotes. At the CSN2 locus the statistically highly significant order of degree of expression was C>B>A. At the LGB locus allele both breeds showed higher expression than allele B and the difference between the expression of the two alleles in heterozygotes is twice of that observed in homozygotes. The CSN1S1 and CSN2 loci affected the synthesis of all caseins. The CSN3 locus shows statistically significant influence on κ-CN in FV. κ-CN appears to be influenced in particular by C2N2 alleles. The LGB locus shows much influence on the ß-LG content but little on caseins. The effects of CSN1S1 and CSN2 loci on the contents of αS2-CN and k-CN indicate epistasis. Polygenic influence accounted for one third to one half of the overall genetic variance of contents of Ca-sensitive caseins. k-CN shows much greater polygenic influence (two thirds to four fifth of the genetic variance) and ß-LG less (1/6 and less). The action of LGB was specific with none or very little influence on the caseins. Moreover, ß-LG was also unaffected by the casein loci. The effects of the alleles on the contents were similar in the two breeds. Repeatabilities were 2/5 to almost 3/5, heritabilities 1/4 to 1/3 with the exception of αS2-CN and k-CN where it was lower.

The Effect of Vocabulary Intervention on Text Comprehension: Who Benefits?

2019 ◽  
Vol 50 (4) ◽  
pp. 562-578 ◽  
Author(s):  
Dawna Duff
Keyword(s):  
Middle School ◽  
Reading Comprehension ◽  
Text Comprehension ◽  
Classroom Instruction ◽  
Vocabulary Instruction ◽  
Clinical Intervention ◽  
Vocabulary Knowledge ◽  
Vocabulary Intervention ◽  
The Mean ◽  
The Difference

Purpose Vocabulary intervention can improve comprehension of texts containing taught words, but it is unclear if all middle school readers get this benefit. This study tests 2 hypotheses about variables that predict response to vocabulary treatment on text comprehension: gains in vocabulary knowledge due to treatment and pretreatment reading comprehension scores. Method Students in Grade 6 ( N = 23) completed a 5-session intervention based on robust vocabulary instruction (RVI). Knowledge of the semantics of taught words was measured pre- and posttreatment. Participants then read 2 matched texts, 1 containing taught words (treated) and 1 not (untreated). Treated texts and taught word lists were counterbalanced across participants. The difference between text comprehension scores in treated and untreated conditions was taken as a measure of the effect of RVI on text comprehension. Results RVI resulted in significant gains in knowledge of taught words ( d RM = 2.26) and text comprehension ( d RM = 0.31). The extent of gains in vocabulary knowledge after vocabulary treatment did not predict the effect of RVI on comprehension of texts. However, untreated reading comprehension scores moderated the effect of the vocabulary treatment on text comprehension: Lower reading comprehension was associated with greater gains in text comprehension. Readers with comprehension scores below the mean experienced large gains in comprehension, but those with average/above average reading comprehension scores did not. Conclusion Vocabulary instruction had a larger effect on text comprehension for readers in Grade 6 who had lower untreated reading comprehension scores. In contrast, the amount that children learned about taught vocabulary did not predict the effect of vocabulary instruction on text comprehension. This has implications for the identification of 6th-grade students who would benefit from classroom instruction or clinical intervention targeting vocabulary knowledge.

Efficacy and Safety of Oral Ivermectin and Topical Permethrin in the Treatment of Scabies

2020 ◽  
Vol 33 (1) ◽  
pp. 41-47
Author(s):  
Mohsena Akhter ◽  
Ishrat Bhuiyan ◽  
Zulfiqer Hossain Khan ◽  
Mahfuza Akhter ◽  
Gulam Kazem Ali Ahmad ◽  
...  
Keyword(s):  
Skin Diseases ◽  
Close Contact ◽  
Randomized Study ◽  
Sarcoptes Scabiei ◽  
Efficacy And Safety ◽  
Common Skin ◽  
Group A ◽  
The Mean ◽  
The Difference ◽  
Group B

Background: Scabies is one of the most common skin diseases in our country. It is caused by the mite Sarcoptes scabiei var hominis, which is an ecto-parasite infesting the epidermis. Scabies is highly contagious. Prevalence is high in congested or densely populated areas. Individuals with close contact with an affected person should be treated with scabicidal which is available in both oral and topical formulations. The only oral but highly effective scabicidal known to date is Ivermectin. Amongst topical preparations, Permethrin 5 % cream is the treatment of choice. Objective: To evaluate the efficacy & safety of oral Ivermectin compared to topical Permethrin in the treatment of scabies. Methodology: This prospective, non-randomized study was conducted at the out-patient department of Dermatology and Venereology of Shaheed Suhrawardy Medical College & Hospital over a period of 6 months, from August 2016 to January 2017. The study population consisted of one hundred patients having scabies, enrolled according to inclusion criteria. They were divided into two groups. group A was subjected to oral Ivermectin and the group B to Permethrin 5% cream. Patients were followed up on day 7 and 14 for assessment of efficacy and safety. Result: The mean scoring with SD in group A (Ivermectin) and group B (Permethrin) were 8.26 ± 2.22 and 7.59 ± 2.01 respectively at the time of observation. The difference between the mean score of the two group is not significant (p=0.117) the mean scoring with SD in group A and group B were 4.54 ± 2.05 and 1.64 ± 1.84 respectively at 7thdays. The difference between the mean score of the two group is significant (p<0.001). The mean scoring with SD in group A and group B were 2.68± 2.35 and .36± 1.10 respectively at 14th day difference between the mean score of the group is significant (p<0.001). Conclusion: Topical application of permethrin 5% cream is more effective and safer than oral Ivermectin in the treatment of scabies. TAJ 2020; 33(1): 41-47

EFFECTS OF SYNTHETIC LH/FSH-RELEASING HORMONE (LRH) ON PLASMA LH AND FSH IN AMENORRHOEIC WOMEN

1974 ◽  
Vol 75 (4) ◽  
pp. 647-652 ◽  
Author(s):  
G. Rannevik ◽  
J. Thorell
Keyword(s):  
Urinary Excretion ◽  
Initial Response ◽  
Releasing Hormone ◽  
The Mean ◽  
The Difference ◽  
Serial Measurements

ABSTRACT Eight amenorrhoeic women were given 100 μg synthetic LRH (Hoechst) iv and im, respectively, at an interval of 2 weeks. Four of the women received the iv injection first and four the im injection. The urinary excretion of oestrogens and pregnanediol was low and unaltered throughout the test weeks. The effects of LRH were compared by serial measurements of the plasma LH and FSH during 8 h. The initial response of LH for up to 25 min and that of FSH for up to 60 min were equal whether LRH was given iv or im. The difference appeared later. Four hours after the injection the mean increase of LH to iv injection was 0.5 ng/ml (N. S.), while that to im injection was 1.9 ng/ml (P < 0.01). The corresponding values for FSH were 1.3 (P < 0.05) and 3.2 (P < 0.001). The effect of LRH administration im was thus found to be larger and more prolonged.

Development of Prolonged Delivery of Tramadol and Dissolution Translation by Statistical Data Treatment

2011 ◽  
Vol 4 (1) ◽  
pp. 1331-1337
Author(s):  
P B Parejiya ◽  
B S Barot ◽  
P K Shelat
Keyword(s):  
Drug Release ◽  
Study Data ◽  
Stability Study ◽  
Dissolution Time ◽  
Matrix Tablet ◽  
Burst Effect ◽  
The Matrix ◽  
The Mean ◽  
The Difference ◽  
Dissolution Efficiency

The present study was carried out to fabricate a prolonged design for tramadol using Kollidon SR (Polyvinyl acetate and povidone based matrix retarding polymer). Matrix tablet formulations were prepared by direct compression of Kollidon SR of a varying proportion with a fixed percentage of tramadol. Tablets containing a 1:0.5 (Drug: Kollidon SR) ratio exhibited a rapid rate of drug release with an initial burst effect. Incorporation of more Kollidon SR in the matrix tablet extended the release of drug with subsequent minimization of the burst effect as confirmed by the mean dissolution time, dissolution efficiency and f2 value. Among the formulation batches, a direct relationship was obtained between release rate and the percentage of Kollidon SR used. The formulation showed close resemblance to the commercial product Contramal and compliance with USP specification. The results were explored and explained by the difference of micromeritic characteristics of the polymers and blend of drug with excipients. Insignificant effects of various factors, e.g. pH of dissolution media, ionic strength, speed of paddle were found on the drug release from Kollidon-SR matrix. The formulation followed the Higuchi kinetic model of drug release. Stability study data indicated stable character of Batch T6 after short-term stability study.

Seasonal trends in the stable isotopic composition of snow and meltwater runoff in a subarctic catchment at Okstindan, Norway

2004 ◽  
Vol 35 (2) ◽  
pp. 119-137 ◽  
Author(s):  
S.D. Gurney ◽  
D.S.L. Lawrence
Keyword(s):  
Isotopic Composition ◽  
Mean Value ◽  
Mean Values ◽  
Stable Isotopic Composition ◽  
Meltwater Runoff ◽  
Stable Isotopic ◽  
The Mean ◽  
The Difference ◽  
Δ18o And Δd

Seasonal variations in the stable isotopic composition of snow and meltwater were investigated in a sub-arctic, mountainous, but non-glacial, catchment at Okstindan in northern Norway based on analyses of δ18O and δD. Samples were collected during four field periods (August 1998; April 1999; June 1999 and August 1999) at three sites lying on an altitudinal transect (740–970 m a.s.l.). Snowpack data display an increase in the mean values of δ18O (increasing from a mean value of −13.51 to −11.49‰ between April and August), as well as a decrease in variability through the melt period. Comparison with a regional meteoric water line indicates that the slope of the δ18O–δD line for the snowpacks decreases over the same period, dropping from 7.49 to approximately 6.2.This change points to the role of evaporation in snowpack ablation and is confirmed by the vertical profile of deuterium excess. Snowpack seepage data, although limited, also suggest reduced values of δD, as might be associated with local evaporation during meltwater generation. In general, meltwaters were depleted in δ18O relative to the source snowpack at the peak of the melt (June), but later in the year (August) the difference between the two was not statistically significant. The diurnal pattern of isotopic composition indicates that the most depleted meltwaters coincide with the peak in temperature and, hence, meltwater production.

Study of pumping effect in flow-through electrolysers

1983 ◽  
Vol 48 (8) ◽  
pp. 2232-2248 ◽  
Author(s):  
Ivo Roušar ◽  
Michal Provazník ◽  
Pavel Stuhl
Keyword(s):  
Natural Convection ◽  
Balance Equation ◽  
Volume Fraction ◽  
Industrial Applications ◽  
Pumping Effect ◽  
Flow Through ◽  
The Mean ◽  
The Difference

In electrolysers with recirculation, where a gas is evolved, the pumping of electrolyte from a lower to a higher level can be effected by natural convection due to the difference between the densities of the inlet electrolyte and the gaseous emulsion at the outlet. An accurate balance equation for calculation of the rate of flow of the pumped liquid is derived. An equation for the calculation of the mean volume fraction of bubbles in the space between the electrodes is proposed and verified experimentally on a pilot electrolyser. Two examples of industrial applications are presented.

Propensity-adjusted cost analysis of radial versus femoral access for neuroendovascular procedures

2020 ◽  
pp. neurintsurg-2020-016728
Author(s):  
Joshua S Catapano ◽  
Andrew F Ducruet ◽  
Stefan W Koester ◽  
Tyler S Cole ◽  
Jacob F Baranoski ◽  
...  
Keyword(s):  
Hospital Stay ◽  
Hospital Costs ◽  
Length Of Hospital Stay ◽  
Diagnostic Procedures ◽  
Femoral Access ◽  
Catheter Size ◽  
The Mean ◽  
The Difference ◽  
Procedure Type ◽  
Angiographic Findings

BackgroundTransradial artery (TRA) access for neuroendovascular procedures is associated with fewer complications than transfemoral artery (TFA) access. This study compares hospital costs associated with TRA access to those associated with TFA access for neurointerventions.MethodsElective neuroendovascular procedures at a single center were retrospectively analyzed from October 1, 2018 to May 31, 2019. Hospital costs for each procedure were obtained from the hospital financial department. The primary outcome was the difference in the mean hospital costs after propensity adjustment between patients who underwent TRA compared with TFA access.ResultsOf the 338 elective procedures included, 63 (19%) were performed through TRA versus 275 (81%) through TFA access. Diagnostic procedures were more common in the TRA cohort (51 of 63, 81%) compared with the TFA cohort (197 of 275, 72%), but the difference was not significant (p=0.48). The TRA cohort had a shorter length of hospital stay (mean (SD) 0.3 (0.5) days) compared with the TFA cohort (mean 0.7 (1.3) days; p=0.02) and lower hospital costs (mean $12 968 ($6518) compared with the TFA cohort (mean $17 150 ($10 946); p=0.004). After propensity adjustment for age, sex, symptoms, angiographic findings, procedure type, sheath size, and catheter size, TRA access was associated with a mean hospital cost of $2514 less than that for TFA access (95% CI −$4931 to −$97; p=0.04).ConclusionNeuroendovascular procedures performed through TRA access are associated with lower hospital costs than TFA procedures. The lower cost is likely due to a decreased length of hospital stay for TRA.

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