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Sample records for inbreeding coefficients higher

  1. Estimating inbreeding coefficients from NGS data

    DEFF Research Database (Denmark)

    Garrett Vieira, Filipe Jorge; Fumagalli, Matteo; Albrechtsen, Anders

    2013-01-01

    Most methods for Next-Generation Sequencing (NGS) data analyses incorporate information regarding allele frequencies using the assumption of Hardy-Weinberg Equilibrium (HWE) as a prior. However, many organisms including domesticated, partially selfing or with asexual life cycles show strong......-Maximization (EM) algorithm. We assess the impact of taking inbreeding into account when calling genotypes or estimating the Site Frequency Spectrum (SFS), and demonstrate a marked increase in accuracy on low coverage highly inbred samples. We demonstrate the applicability and efficacy of these methods in both...

  2. Analysis of genetic diversity and estimation of inbreeding coefficient ...

    African Journals Online (AJOL)

    Analysis of genetic diversity and estimation of inbreeding coefficient within Caspian horse population using microsatellite markers. ... structure and to the assessment of genetic diversity that may be helpful to horse breeders in designing and managing breeding or conservation strategies for the Caspian horse breed.

  3. The association of genotype-based inbreeding coefficient with a range of physical and psychological human traits.

    Directory of Open Access Journals (Sweden)

    Karin J H Verweij

    Full Text Available Across animal species, offspring of closely related mates exhibit lower fitness, a phenomenon called inbreeding depression. Inbreeding depression in humans is less well understood because mating between close relatives is generally rare and stigmatised, confounding investigation of its effect on fitness-relevant traits. Recently, the availability of high-density genotype data has enabled quantification of variation in distant inbreeding in 'outbred' human populations, but the low variance of inbreeding detected from genetic data in most outbred populations means large samples are required to test effects, and only a few traits have yet been studied. However, it is likely that isolated populations, or those with a small effective population size, have higher variation in inbreeding and therefore require smaller sample sizes to detect inbreeding effects. With a small effective population size and low immigration, Northern Finland is such a population. We make use of a sample of ∼5,500 'unrelated' individuals in the Northern Finnish Birth Cohort 1966 with known genotypes and measured phenotypes across a range of fitness-relevant physical and psychological traits, including birth length and adult height, body mass index (BMI, waist-to-hip ratio, blood pressure, heart rate, grip strength, educational attainment, income, marital status, handedness, health, and schizotypal features. We find significant associations in the predicted direction between individuals' inbreeding coefficient (measured by proportion of the genome in runs of homozygosity and eight of the 18 traits investigated, significantly more than the one or two expected by chance. These results are consistent with inbreeding depression effects on a range of human traits, but further research is needed to replicate and test alternative explanations for these effects.

  4. Estimation of Inbreeding Coefficient and Its Effects on Lamb Survival in Sheep

    Directory of Open Access Journals (Sweden)

    mohammad almasi

    2016-04-01

    Full Text Available Introduction The mating of related individuals produces an inbred offspring and leads to an increased homozygosity in the progeny, genetic variance decrease within families and increase between families. The ration of homozygosity for individuals was calculated by inbreeding coefficient. Inbred individuals may carry two alleles at a locus that are replicated from one gene in the previous generations, called identical by descent. The inbreeding coefficient should be monitored in a breeding program, since it plays an important role at decreasing of homeostasis, performance, reproduction and viability. The trend of inbreeding is an indicator for determining of inbreeding level in the herd. Inbreeding affects both phenotypic means of traits and genetic variances within population, thus it is an important factor for delimitations of genetic progress in a population. Reports showed an inbreeding increase led to decrease of phenotypic value in some of the productive and reproductive traits. Materials and Methods In the current study, the pedigree data of 14030 and 6215 records of Baluchi and Iranblack lambs that collected from 1984 to 2011 at the Abbasabad Sheep Breeding Station in Mashhad, Iran, 3588 records of Makoei lambs that collected from 1994 to 2011 at the Makoei sheep breeding station and 6140, records of Zandi lambs that collected from 1991 to 2011 at the Khejir Sheep Breeding Station in Tehran, Iran were used to estimating the inbreeding coefficient and its effects on lamb survival in these breeds. Lamb survival trait was scored as 1 and 0 for lamb surviving and not surviving at weaning weight, respectively. Inbreeding coefficient was estimated by relationship matrix algorithm (A=TDT' methodology using the CFC software program. Effects of inbreeding coefficient on lamb survival were estimated by restricted maximum likelihood (REML method under 12 different animal models using ASReml 3.0 computer programme. Coefficient of inbreeding for each

  5. On the expected relationship between inbreeding, fitness, and extinction

    Directory of Open Access Journals (Sweden)

    Couvet Denis

    2006-06-01

    Full Text Available Abstract We assessed the expected relationship between the level and the cost of inbreeding, measured either in terms of fitness, inbreeding depression or probability of extinction. First, we show that the assumption of frequent, slightly deleterious mutations do agree with observations and experiments, on the contrary to the assumption of few, moderately deleterious mutations. For the same inbreeding coefficient, populations can greatly differ in fitness according to the following: (i population size; larger populations show higher fitness (ii the history of population size; in a population that recovers after a bottleneck, higher inbreeding can lead to higher fitness and (iii population demography; population growth rate and carrying capacity determine the relationship between inbreeding and extinction. With regards to the relationship between inbreeding depression and inbreeding coefficient, the population size that minimizes inbreeding depression depends on the level of inbreeding: inbreeding depression can even decrease when population size increases. It is therefore clear that to infer the costs of inbreeding, one must know both the history of inbreeding (e.g. past bottlenecks and population demography.

  6. The association of genotype-based inbreeding coefficient with a range of physical and psychological human traits

    NARCIS (Netherlands)

    Verweij, K.J.H.; Abdellaoui, A.; Veijola, J.; Sebert, S.; Koiranen, M.; Keller, M.C.; Jarvelin, M.R.; Zietsch, B.P.

    2014-01-01

    Across animal species, offspring of closely related mates exhibit lower fitness, a phenomenon called inbreeding depression. Inbreeding depression in humans is less well understood because mating between close relatives is generally rare and stigmatised, confounding investigation of its effect on

  7. The Association of Genotype-Based Inbreeding Coefficient with a Range of Physical and Psychological Human Traits

    NARCIS (Netherlands)

    Verweij, K.J.H.; Abdellaoui, A.; Veijola, J.; Sebert, S.; Koiranen, M.; Keller, M.C.; Järvelin, M.R.; Zietsch, B.P.

    2014-01-01

    Across animal species, offspring of closely related mates exhibit lower fitness, a phenomenon called inbreeding depression. Inbreeding depression in humans is less well understood because mating between close relatives is generally rare and stigmatised, confounding investigation of its effect on

  8. Inbreeding and inbreeding depression in endangered red wolves (Canis rufus).

    Science.gov (United States)

    Brzeski, Kristin E; Rabon, David R; Chamberlain, Michael J; Waits, Lisette P; Taylor, Sabrina S

    2014-09-01

    In natural populations, the expression and severity of inbreeding depression can vary widely across taxa. Describing processes that influence the extent of inbreeding and inbreeding depression aid in our understanding of the evolutionary history of mating systems such as cooperative breeding and nonrandom mate selection. Such findings also help shape wildlife conservation theory because inbreeding depression reduces the viability of small populations. We evaluated the extent of inbreeding and inbreeding depression in a small, re-introduced population of red wolves (Canis rufus) in North Carolina. Since red wolves were first re-introduced in 1987, pedigree inbreeding coefficients (f) increased considerably and almost every wild born wolf was inbred (average f = 0.154 and max f = 0.383). The large inbreeding coefficients were due to both background relatedness associated with few founders and numerous close relative matings. Inbreeding depression was most evident for adult body size and generally absent for direct fitness measures such as reproductive success and survival; no lethal equivalents (LE = 0.00) were detected in juvenile survival. The lack of strong inbreeding depression in direct measures of fitness could be due to a founder effect or because there were no outbred individuals for comparison. Our results highlight the variable expression of inbreeding depression across traits and the need to measure a number of different traits when evaluating inbreeding depression in a wild population. © 2014 John Wiley & Sons Ltd.

  9. Inbreeding among Caribbean Hispanics from the Dominican Republic and its effects on risk of Alzheimer disease.

    Science.gov (United States)

    Vardarajan, Badri N; Schaid, Daniel J; Reitz, Christiane; Lantigua, Rafael; Medrano, Martin; Jiménez-Velázquez, Ivonne Z; Lee, Joseph H; Ghani, Mahdi; Rogaeva, Ekaterina; St George-Hyslop, Peter; Mayeux, Richard P

    2015-08-01

    Inbreeding can be associated with a modification of disease risk due to excess homozygosity of recessive alleles affecting a wide range of phenotypes. We estimated the inbreeding coefficient in Caribbean Hispanics and examined its effects on risk of late-onset Alzheimer disease. The inbreeding coefficient was calculated in 3,392 subjects (1,451 late-onset Alzheimer disease patients and 1,941 age-matched healthy controls) of Caribbean Hispanic ancestry using 177,997 nearly independent single-nucleotide polymorphisms from genome-wide array. The inbreeding coefficient was estimated using the excess homozygosity method with and without adjusting for admixture. The average inbreeding coefficient in Caribbean Hispanics without accounting for admixture was F = 0.018 (±0.048), suggesting a mating equivalent to that of second cousins or second cousins once removed. Adjusting for admixture from three parent populations, the average inbreeding coefficient was found to be 0.0034 (±0.019) or close to third-cousin mating. Inbreeding coefficient was a significant predictor of Alzheimer disease when age, sex, and APOE genotype were used as adjusting covariates (P = 0.03). The average inbreeding coefficient of this population is significantly higher than that of the general Caucasian populations in North America. The high rate of inbreeding resulting in increased frequency of recessive variants is advantageous for the identification of rare variants associated with late-onset Alzheimer disease.Genet Med 17 8, 639-643.

  10. Inbreeding and PKU allele frequency: Estimating by microsatellite approaches.

    Science.gov (United States)

    Santos, Luciana L; da Fonseca, Cleusa G; Vaintraub, Marco T; Vaintraub, Patricia; Januário, José N; de Aguiar, Marcos J B; Raquel Santos Carvalho, Maria

    2010-01-01

    Estimates of allele frequencies for recessive diseases are generally based on the frequency of affected individuals (q(2)). However, these estimates can be strongly biased due to inbreeding in the population. The purpose of this study was to gain a better understanding of how inbreeding in the Minas Gerais State population affects phenylketonuria (PKU) incidence in the state and to determine the inbreeding coefficient based on microsatellites. Inbreeding coefficients of samples of 104 controls and 76 patients with PKU were estimated through a microsatellite approach. Besides, the amount and distribution of genetic variation within and among patients with PKU and control samples were characterized. No genetic differentiation was observed between the samples. However, the Fis value found for samples of patients with PKU (0.042) was almost 15 times higher than that found among controls (0.003). When corrected by the inbreeding coefficient found among the controls, the PKU allele frequency decreased to 0.0057. The results enables us to infer that at least 35% of the PKU recessive homozygotes from the Minas Gerais population could be due to consanguineous marriages and suggest that microsatellites can be an useful approach to estimate inbreeding coefficients. (c) 2010 Wiley-Liss, Inc.

  11. Monitoring inbreeding trends and inbreeding depression for economically important traits of Holstein cattle in Iran

    DEFF Research Database (Denmark)

    Rokouei, M; Torshizi, R Vaez; Shahrbabak, M Moradi

    2010-01-01

    reproductive traits, the observed undesirable effect of inbreeding was not significant, except for the calving interval (0.53 d per 1% increase in inbreeding) in the third parity and age at first calving (0.45 d per 1% increase in inbreeding). Calving ease in heifers and cows was significantly influenced...... scores than animals with low inbreeding coefficients. For type traits, the influence of inbreeding was significant only for stature, chest width, body depth, size, rear udder height, suspensory ligament, udder depth, and front and rear teat placement. Cows with high levels of inbreeding coefficient were...

  12. Inbreeding patterns in the Gredos Mountain Range (Spain).

    Science.gov (United States)

    Fuster, V; Morales, B; Mesa, M S; Martin, J

    1996-02-01

    The relationships among the frequency of consanguineous marriages, inbreeding coefficient, period, village size, and altitude are analyzed for three rural valleys belonging to the Sierra de Gredos (central Spain). These valleys occupy an area of about 30 x 80 km2, and the average total number of inhabitants for the period 1877-1970 was 58,621. Information about a sample of 23,744 weddings celebrated between 1875 and 1974 was obtained from 48 village parish registers. The mean inbreeding level up to second cousins for the whole area was 0.0012. A high percentage of inbreeding variation (83%) can be explained by each village's census size, resulting in a different interslope consanguinity pattern consisting of higher inbreeding levels in most northern localities in the Gredos mountains. This north-south geographic trend is consistent with results on blood polymorphisms from the same area (Mesa et al. 1994).

  13. Assessment of inbreeding depression for functional herd life in the ...

    African Journals Online (AJOL)

    p2492989

    in Spanish dairy cattle. From the results of a study with Spanish horses, Gómez et al. (2009) recommended the use of the individual increase in inbreeding coefficient (∆Fi) instead of the individual inbreeding coefficient (Fi) owing to the better fit with data and the special property whereby individual inbreeding coefficients are ...

  14. Exact coefficients for higher dimensional operators with sixteen supersymmetries

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Wei-Ming [Department of Physics and Astronomy, National Taiwan University,Taipei 10617, Taiwan, R.O.C. (China); Huang, Yu-tin [Department of Physics and Astronomy, National Taiwan University,Taipei 10617, Taiwan, R.O.C. (China); School of Natural Sciences, Institute for Advanced Study,Princeton, NJ 08540 (United States); Wen, Congkao [INFN Sezione di Roma “Tor Vergata' ,Via della Ricerca Scientifica, 00133 Roma (Italy)

    2015-09-15

    We consider constraints on higher-dimensional operators for supersymmetric effective field theories. In four dimensions with maximal supersymmetry and SU(4) R-symmetry, we demonstrate that the coefficients of abelian operators F{sup n} with MHV helicity configurations must satisfy a recursion relation, and are completely determined by that of F{sup 4}. As the F{sup 4} coefficient is known to be one-loop exact, this allows us to derive exact coefficients for all such operators. We also argue that the results are consistent with the SL(2,Z) duality symmetry. Breaking SU(4) to Sp(4), in anticipation for the Coulomb branch effective action, we again find an infinite class of operators whose coefficients are determined exactly. We also consider three-dimensional N=8 as well as six-dimensional N=(2,0),(1,0) and (1,1) theories. In all cases, we demonstrate that the coefficient of dimension-six operator must be proportional to the square of that of dimension-four.

  15. Exact coefficients for higher dimensional operators with sixteen supersymmetries

    Science.gov (United States)

    Chen, Wei-Ming; Huang, Yu-tin; Wen, Congkao

    2015-09-01

    We consider constraints on higher-dimensional operators for supersymmetric effective field theories. In four dimensions with maximal supersymmetry and SU(4) R-symmetry, we demonstrate that the coefficients of abelian operators F n with MHV helicity configurations must satisfy a recursion relation, and are completely determined by that of F 4. As the F 4 coefficient is known to be one-loop exact, this allows us to derive exact coefficients for all such operators. We also argue that the results are consistent with the SL(2,Z) duality symmetry. Breaking SU(4) to Sp(4), in anticipation for the Coulomb branch effective action, we again find an infinite class of operators whose coefficients are determined exactly. We also consider three-dimensional N = 8 as well as six-dimensional N = (2 ,0) ,(1 ,0) and (1 ,1) theories. In all cases, we demonstrate that the coefficient of dimension-six operator must be proportional to the square of that of dimension-four.

  16. Time within reproductive season, but not age or inbreeding coefficient, influences seminal and sperm quality in the whooping crane (Grus americana)

    Science.gov (United States)

    Brown, M.E.; Converse, Sarah; Chandler, Jane N.; Crosier, A. L.; Lynch, W.; Wildt, D.E.; Keefer, C. L.; Songsasen, Nucharin

    2015-01-01

    All living whooping cranes (Grus americana) are descended from 16 or fewer birds that remained alive in the early 1940s, a bottleneck that puts the species at potential risk for inbreeding depression. Although AI is commonly used in the management of the captive population of this species, little is known about seminal traits or factors affecting sperm quality in the whooping crane. In the present study, semen samples were collected from 29 adult males (age 3–27 years) during the early (March), mid (April) and late (May) breeding season over 2 consecutive years. The effects of donor age, time within reproductive season and level of inbreeding on seminal characteristics were analysed using regression and information–theoretic model selection. Only time within reproductive season significantly affected seminal traits, with total numbers of spermatozoa and proportions of pleiomorphisms increasing across the season. We conclude that, even with a highly restricted number of founders, there is no discernible influence of inbreeding (at the levels described) on sperm output or quality. Furthermore, although there is variance in seminal quality, the whooping crane produces significant numbers of motile spermatozoa throughout the breeding season, similar to values reported for the greater sandhill crane (Grus canadensis tabida).

  17. The effects of inbreeding on disease susceptibility: Gyrodactylus turnbulli infection of guppies, Poecilia reticulata.

    Science.gov (United States)

    Smallbone, Willow; van Oosterhout, Cock; Cable, Jo

    2016-08-01

    Inbreeding can threaten population persistence by reducing disease resistance through the accelerated loss of gene diversity (i.e. heterozygosity). Such inbreeding depression can affect many different fitness-related traits, including survival, reproductive success, and parasite susceptibility. Empirically quantifying the effects of inbreeding on parasite resistance is therefore important for ex-situ conservation of vertebrates. The present study evaluates the disease susceptibility of individuals bred under three different breeding regimes (inbred, crossed with full siblings; control, randomly crossed mating; and fully outbred). Specifically, we examined the relationship between inbreeding coefficient (F-coefficient) and susceptibility to Gyrodactylus turnbulli infection in a live bearing vertebrate, the guppy Poecilia reticulata. Host-breeding regime significantly affected the trajectories of parasite population growth on individual fish. Inbred fish showed significantly higher mean parasite intensity than fish from the control and outbred breeding regimes, and in addition, inbred fish were slower in purging their gyrodactylid infections. We discuss the role of inbreeding on the various arms of the immune system, and argue that the increased disease susceptibility of inbred individuals could contribute to the extinction vortex. This is one of the first studies to quantify the effects of inbreeding and breeding regime on disease susceptibility in a captive bred vertebrate of wild origin, and it highlights the risks faced by small (captive-bred) populations when exposed to their native parasites. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  18. EFFECT OF INBREEDING ON MORTALITY OF CAPTIVE TIGER

    Directory of Open Access Journals (Sweden)

    Sidharth Prasad Mishra

    2017-06-01

    Full Text Available A study was carried out on the captive tigers of Nandankanan zoo, Odisha, India, to conclude any deleterious effect of inbreeding on mortality. A pedigree path analysis of 342 tigers was done to estimate the inbreeding coefficient of each tiger from the available pedigree information since the inception of zoological park in 1964. Percentage of animal with different range of inbreeding coefficient was classified based on their normal and white body coat colour. The correlation values between sex, colour and inbreeding coefficient with mortality were also estimated. The colour and inbreeding coefficient was found to be significantly (p<0.05 correlated with the mortality. The inbreeding was found to be significant (p<0.05 with white colour of tiger.

  19. Inbreeding avoidance in an isolated indigenous Zapotec community in the valley of Oaxaca, southern Mexico.

    Science.gov (United States)

    Little, Bertis B; Malina, Robert M

    2005-06-01

    We analyzed inbreeding using surname isonymy in an indigenous genetic isolate. The subjects were residents of a rural Zapotec-speaking community in the valley of Oaxaca, southern Mexico. The community can be classified as a genetic isolate with an average gene flow of indigenous Mexican populations. A total of 2,149 individuals had valid surname patronym-matronym pairings, including 484 deceased ancestors. Surname isonymy analysis methods were used to estimate total inbreeding and to segregate it into random and nonrandom components. The surname isonymy coefficient computed from 119 isonymous surname pairings (119/2,149) was 0.0554. The estimated inbreeding coefficient from surname isonymy was 0.0138 (0.0554/4). The random and nonrandom components of inbreeding were F(r) = 0.0221 and F(n) = -0.0091, respectively. The results suggest that consanguinity is culturally avoided. Nonrandom inbreeding decreased total inbreeding by about 41%. Total estimated inbreeding by surname isonymy was 0.0138, which is similar to inbreeding estimated from a sample of pedigrees, 0.01. Socially prescribed inbreeding avoidance substantially lowered total F through negative nonrandom inbreeding. Even in the situation of genetic isolation and small effective population size (N(e)), estimated inbreeding is lower than may have otherwise occurred if inbreeding were only random. However, among the poorest individuals, socially prescribed jural rules for inbreeding avoidance failed to operate. Thus the preponderance of inbreeding appears to occur among the poor, economically disadvantaged in the community.

  20. Higher-order Cn dispersion coefficients for hydrogen

    International Nuclear Information System (INIS)

    Mitroy, J.; Bromley, M.W.J.

    2005-01-01

    The complete set of second-, third-, and fourth-order van der Waals coefficients C n up to n=32 for the H(1s)-H(1s) dimer have been determined. They are computed by diagonalizing the nonrelativistic Hamiltonian for hydrogen to obtain a set of pseudostates that are used to evaluate the appropriate sum rules. A study of the convergence pattern for n≤16 indicates that all the C n/16 coefficients are accurate to 13 significant digits. The relative size of the fourth-order C n (4) to the second-order C n (2) coefficients is seen to increase as n increases and at n=32 the fourth-order term is actually larger

  1. Countering inbreeding with migration 2. Migration from related ...

    African Journals Online (AJOL)

    of migration rates is judged by the maximum difference ( 1 - k) in inbreeding between a subpopulation, of size N, and a con- ceptual aggregate random ... inbreeding coefficient of a subpopulation (single island) with migration from a very large noninbred population, ll(4M + l). ...... WH Freeman and Company, New York.

  2. Presence of inbreeding during a selection experiment with Merino ...

    African Journals Online (AJOL)

    192 individual inbreeding coefficients on natural and artificial selection cannot be ruled out. The effect of inbreeding on production and reproduction traits in Merino sheep has been the subject of many studies and reviews (Morley, 1954; Doney,. 1957; Lax & Brown, 1967; Turner & Young, 1969; Dolling,. 1970' Lamberson ...

  3. Does haplodiploidy purge inbreeding depression in rotifer populations?

    Directory of Open Access Journals (Sweden)

    Ana M Tortajada

    2009-12-01

    Full Text Available Inbreeding depression is an important evolutionary factor, particularly when new habitats are colonized by few individuals. Then, inbreeding depression by drift could favour the establishment of later immigrants because their hybrid offspring would enjoy higher fitness. Rotifers are the only major zooplanktonic group where information on inbreeding depression is still critically scarce, despite the fact that in cyclical parthenogenetic rotifers males are haploid and could purge deleterious recessive alleles, thereby decreasing inbreeding depression.We studied the effects of inbreeding in two populations of the cyclical parthenogenetic rotifer Brachionus plicatilis. For each population, we compared both the parental fertilization proportion and F1 fitness components from intraclonal (selfed and interclonal (outcrossed crosses. The parental fertilization proportion was similar for both types of crosses, suggesting that there is no mechanism to avoid selfing. In the F1 generation of both populations, we found evidence of inbreeding depression for the fitness components associated with asexual reproduction; whereas inbreeding depression was only found for one of the two sexual reproduction fitness components measured.Our results show that rotifers, like other major zooplanktonic groups, can be affected by inbreeding depression in different stages of their life cycle. These results suggest that haplodiploidy does not purge efficiently deleterious recessive alleles. The inbreeding depression detected here has important implications when a rotifer population is founded and intraclonal crossing is likely to occur. Thus, during the foundation of new populations inbreeding depression may provide opportunities for new immigrants, increasing gene flow between populations, and affecting genetic differentiation.

  4. Genomic dissection of inbreeding depression: a gate to new opportunities

    Directory of Open Access Journals (Sweden)

    Ino Curik

    Full Text Available ABSTRACT Inbreeding depression, reduction in performance of quantitative traits, including reproduction and survival, caused by inbreeding, is a well-known phenomenon observed in almost all experimental, domesticated, and natural populations. In spite of its importance to the fate of a small population and numerous research performed in the last century, the genetic basis of inbreeding depression is still unclear. Recent fast development of molecular techniques has enabled estimation of a genomic inbreeding coefficient (FROH, which reflects realized autozygosity and can be further partitioned to chromosomes and chromosomal segments. In this review, we first describe classical approach used in the estimation of inbreeding in livestock populations, followed by early concepts of replacing pedigree inbreeding coefficient by individual heterozygosity. Then, we explain runs of homozygosity as key approach in estimating realized autozygosity. Furthermore, we present two different concepts of analysing regions that substantially contribute to the inbreeding depression. Thus, we describe how to identify or map mutations that result in the reduction of performance and, in terms of quantitative genetics, how to analyse the architecture of inbreeding depression. At the end, we discuss future perspectives in eliminating deleterious mutations from livestock populations.

  5. Estimating the inbreeding depression on cognitive behavior: a population based study of child cohort.

    Directory of Open Access Journals (Sweden)

    Mohd Fareed

    Full Text Available Cognitive ability tests are widely assumed to measure maximal intellectual performance and predictive associations between intelligence quotient (IQ scores and later mental health problems. Very few epidemiologic studies have been done to demonstrate the relationship between familial inbreeding and modest cognitive impairments in children.We aimed to estimate the effect of inbreeding on children's cognitive behavior in comparison with non-inbred children.A cohort of 408 children (6 to 15 years of age was selected from inbred and non-inbred families of five Muslim populations of Jammu region. The Wechsler Intelligence Scales for Children (WISC was used to measure the verbal IQ (VIQ, performance IQ (PIQ and full scale IQ (FSIQ. Family pedigrees were drawn to access the family history and children's inbred status in terms of coefficient of inbreeding (F.We found significant decline in child cognitive abilities due to inbreeding and high frequency of mental retardation among offspring from inbred families. The mean differences (95% C.I. were reported for the VIQ, being -22.00 (-24.82, -19.17, PIQ -26.92 (-29.96, -23.87 and FSIQ -24.47 (-27.35,-21.59 for inbred as compared to non-inbred children (p<0.001 [corrected].The higher risk of being mentally retarded was found to be more obvious among inbred categories corresponding to the degree of inbreeding and the same accounts least for non-inbred children (p<0.0001. We observed an increase in the difference in mean values for VIQ, PIQ and FSIQ with the increase of inbreeding coefficient and these were found to be statistically significant (p<0.05. The regression analysis showed a fitness decline (depression for VIQ (R2 = 0.436, PIQ (R2 = 0.468 and FSIQ (R2 = 0.464 with increasing inbreeding coefficients (p<0.01.Our comprehensive assessment provides the evidence for inbreeding depression on cognitive abilities among children.

  6. Inbreeding depression across a nutritional stress continuum.

    Science.gov (United States)

    Schou, M F; Loeschcke, V; Kristensen, T N

    2015-07-01

    Many natural populations experience inbreeding and genetic drift as a consequence of nonrandom mating or low population size. Furthermore, they face environmental challenges that may interact synergistically with deleterious consequences of increased homozygosity and further decrease fitness. Most studies on inbreeding-environment (I-E) interactions use one or two stress levels, whereby the resolution of the possible stress and inbreeding depression interaction is low. Here we produced Drosophila melanogaster replicate populations, maintained at three different population sizes (10, 50 and a control size of 500) for 25 generations. A nutritional stress gradient was imposed on the replicate populations by exposing them to 11 different concentrations of yeast in the developmental medium. We assessed the consequences of nutritional stress by scoring egg-to-adult viability and body mass of emerged flies. We found: (1) unequivocal evidence for I-E interactions in egg-to-adult viability and to a lesser extent in dry body mass, with inbreeding depression being more severe under higher levels of nutritional stress; (2) a steeper increase in inbreeding depression for replicate populations of size 10 with increasing nutritional stress than for replicate populations of size 50; (3) a nonlinear norm of reaction between inbreeding depression and nutritional stress; and (4) a faster increase in number of lethal equivalents in replicate populations of size 10 compared with replicate populations of size 50 with increasing nutritional stress levels. Our data provide novel and strong evidence that deleterious fitness consequences of I-E interactions are more pronounced at higher nutritional stress and at higher inbreeding levels.

  7. Inbreeding and inbreeding avoidance in wild giant pandas.

    Science.gov (United States)

    Hu, Yibo; Nie, Yonggang; Wei, Wei; Ma, Tianxiao; Van Horn, Russell; Zheng, Xiaoguang; Swaisgood, Ronald R; Zhou, Zhixin; Zhou, Wenliang; Yan, Li; Zhang, Zejun; Wei, Fuwen

    2017-10-01

    Inbreeding can have negative consequences on population and individual fitness, which could be counteracted by inbreeding avoidance mechanisms. However, the inbreeding risk and inbreeding avoidance mechanisms in endangered species are less studied. The giant panda, a solitary and threatened species, lives in many small populations and suffers from habitat fragmentation, which may aggravate the risk of inbreeding. Here, we performed long-term observations of reproductive behaviour, sampling of mother-cub pairs and large-scale genetic analyses on wild giant pandas. Moderate levels of inbreeding were found in 21.1% of mating pairs, 9.1% of parent pairs and 7.7% of panda cubs, but no high-level inbreeding occurred. More significant levels of inbreeding may be avoided passively by female-biased natal dispersal rather than by breeding dispersal or active relatedness-based mate choice mechanisms. The level of inbreeding in giant pandas is greater than expected for a solitary mammal and thus warrants concern for potential inbreeding depression, particularly in small populations isolated by continuing habitat fragmentation, which will reduce female dispersal and increase the risk of inbreeding. © 2017 John Wiley & Sons Ltd.

  8. Inbreeding and diseases: demographic, genetic, and epidemiologic perspectives.

    Science.gov (United States)

    Khlat, M; Khoury, M

    1991-01-01

    The demographic and quantitative genetic aspects of consanguineous marriages are reviewed before epidemiologic principles are applied to the hundreds of studies reviewed, and 3 in particular. Consanguineous unions range from cousin-cousin to more distant relatedness, and their prevalence varies by culture. Prevalence is highest in Arab countries, followed by India, Japan, Brazil and Israel. They are most common in lower educational and socioeconomic groups, the traditionally religious, and the early married, but are declining with modernization. Consanguinity is measured by geneticists by the inbreeding coefficient, the mean consanguinity of a population, and the concept of genetic load. Recessive genes may be deleterious or beneficial if heterozygous in local conditions. Bayesian statistics can predict by the coefficient of increase the probability of disease in offspring as a function of consanguinity and disease characteristics. Inbreeding generally increases prereproductive mortality; crude mortality increases with inbreeding in proportion to the mortality rate. Morbidity increases significantly with inbreeding in many diseases studies in many countries. Epidemiologic studies usually measure inbreeding effects in terms of genetic load, which is not readily translatable into morbidity and mortality. Several methods of computing results of epidemiologic studies are discussed, as well as methodological study design problems. Confounding is the most difficult problem in these studies, because of the difficulty in selecting non-inbred controls. Future inbreeding studies should be interpreted based on both genetic and epidemiologic grounds to illuminate the role of genetic factors and the relevance of inbreeding to disease and public health.

  9. Fitness costs predict emotional, moral and attitudinal inbreeding aversion

    Directory of Open Access Journals (Sweden)

    Florence Lespiau

    2016-11-01

    Full Text Available In terms of sexual intercourse, the very last people we think about are our kin. Imagining inbreeding intercourse, whether it involves our closest kin or not, induces aversion in most people who invoke inbreeding depression problems or cultural considerations. Research has focused on the disgust felt when facing inbreeding intercourse between close kin but little is known about other responses. In this study, we considered the influence of fitness costs on aversive reactions by including disgust and emotional reaction as well as moral judgment and attitudes towards inbreeding: higher costs should induce a stronger aversive reaction. The fitness costs were manipulated by two factors: (i the degree of the participants’ involvement in the story (themselves, a sib or an unknown individual, and (ii the degree of relatedness between the two inbreeding people (brother/sister, uncle-aunt/niece-nephew, cousin. To test this hypothesis, 140 women read and assessed different inbreeding stories varying in the fitness costs incurred. Findings showed that the higher the fitness costs were, the greater the aversive reaction was in an overall way. First, our results fitted with previous studies that tested the influence of fitness costs on disgust. Second, and more interestingly, findings went further by examining overall aversion, showing that fitness costs could influence emotions felt as well as attitudes and behaviors towards inbreeding people. The higher the fitness costs were, the less inbreeding people were perceived as moral and the more they were considered as a nuisance. However, results regarding avoidance were more nuanced.

  10. Fitness Costs Predict Emotional, Moral, and Attitudinal Inbreeding Aversion.

    Science.gov (United States)

    Lespiau, Florence; Kaminski, Gwenaël

    2016-01-01

    In terms of sexual intercourse, the very last people we think about are our kin. Imagining inbreeding intercourse, whether it involves our closest kin or not, induces aversion in most people who invoke inbreeding depression problems or cultural considerations. Research has focused on the disgust felt when facing inbreeding intercourse between close kin but little is known about other responses. In this study, we considered the influence of fitness costs on aversive reactions by including disgust and emotional reaction as well as moral judgment and attitudes toward inbreeding: higher costs should induce a stronger aversive reaction. The fitness costs were manipulated by two factors: (i) the degree of the participants' involvement in the story (themselves, a sib or an unknown individual), and (ii) the degree of relatedness between the two inbreeding people (brother/sister, uncle-aunt/niece-nephew, cousin). To test this hypothesis, 140 women read and assessed different inbreeding stories varying in the fitness costs incurred. Findings showed that the higher the fitness costs were, the greater the aversive reaction was in an overall way. First, our results fitted with previous studies that tested the influence of fitness costs on disgust. Second, and more interestingly, findings went further by examining overall aversion, showing that fitness costs could influence emotions felt as well as attitudes and behaviors toward inbreeding people. The higher the fitness costs were, the less inbreeding people were perceived as moral and the more they were considered as a nuisance. However, results regarding avoidance were more nuanced.

  11. Feral Pigeons (Columba livia Prefer Genetically Similar Mates despite Inbreeding Depression.

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    Gwenaël Jacob

    Full Text Available Avoidance of mating between related individuals is usually considered adaptive because it decreases the probability of inbreeding depression in offspring. However, mating between related partners can be adaptive if outbreeding depression is stronger than inbreeding depression or if females gain inclusive fitness benefits by mating with close kin. In the present study, we used microsatellite data to infer the parentage of juveniles born in a French colony of feral pigeons, which allowed us to deduce parent pairs. Despite detectable inbreeding depression, we found that pairwise relatedness between mates was significantly higher than between nonmates, with a mean coefficient of relatedness between mates of 0.065, approximately half the theoretical value for first cousins. This higher relatedness between mates cannot be explained by spatial genetic structure in this colonial bird; it therefore probably results from an active choice. As inbreeding but not outbreeding depression is observed in the study population, this finding accords with the idea that mating with genetically similar mates can confer a benefit in terms of inclusive fitness. Our results and published evidence suggest that preference for related individuals as mates might be relatively frequent in birds.

  12. Inbreeding, Microsatellite Heterozygosity, and Morphological Traits in Lipizzan Horses

    OpenAIRE

    Curik, I.; Zechner, P.; Sölkner, J.; Achmann, R.; Bodo, I.; Dovc, P.; Kavar, T.; Marti, E.; Brem, G.

    2017-01-01

    While the negative effects of inbreeding and reduced heterozygosity on fecundity and survival are well established, only a few investigations have been carried out concerning their influence on morphological traits. This topic is of particular interest for a small and closed population such as the Lipizzan horse. Thus, 27 morphological traits were measured in 360 Lipizzan mares and were regressed on the individual inbreeding coefficients, as well as on the individual heterozygosity and mean s...

  13. Genome-wide estimates of coancestry and inbreeding in a closed herd of ancient Iberian pigs.

    Directory of Open Access Journals (Sweden)

    María Saura

    Full Text Available Maintaining genetic variation and controlling the increase in inbreeding are crucial requirements in animal conservation programs. The most widely accepted strategy for achieving these objectives is to maximize the effective population size by minimizing the global coancestry obtained from a particular pedigree. However, for most natural or captive populations genealogical information is absent. In this situation, microsatellites have been traditionally the markers of choice to characterize genetic variation, and several estimators of genealogical coefficients have been developed using marker data, with unsatisfactory results. The development of high-throughput genotyping techniques states the necessity of reviewing the paradigm that genealogical coancestry is the best parameter for measuring genetic diversity. In this study, the Illumina PorcineSNP60 BeadChip was used to obtain genome-wide estimates of rates of coancestry and inbreeding and effective population size for an ancient strain of Iberian pigs that is now in serious danger of extinction and for which very accurate genealogical information is available (the Guadyerbas strain. Genome-wide estimates were compared with those obtained from microsatellite and from pedigree data. Estimates of coancestry and inbreeding computed from the SNP chip were strongly correlated with genealogical estimates and these correlations were substantially higher than those between microsatellite and genealogical coefficients. Also, molecular coancestry computed from SNP information was a better predictor of genealogical coancestry than coancestry computed from microsatellites. Rates of change in coancestry and inbreeding and effective population size estimated from molecular data were very similar to those estimated from genealogical data. However, estimates of effective population size obtained from changes in coancestry or inbreeding differed. Our results indicate that genome-wide information represents a

  14. Quantifying inbreeding avoidance through extra-pair reproduction.

    Science.gov (United States)

    Reid, Jane M; Arcese, Peter; Keller, Lukas F; Germain, Ryan R; Duthie, A Bradley; Losdat, Sylvain; Wolak, Matthew E; Nietlisbach, Pirmin

    2015-01-01

    Extra-pair reproduction is widely hypothesized to allow females to avoid inbreeding with related socially paired males. Consequently, numerous field studies have tested the key predictions that extra-pair offspring are less inbred than females' alternative within-pair offspring, and that the probability of extra-pair reproduction increases with a female's relatedness to her socially paired male. However, such studies rarely measure inbreeding or relatedness sufficiently precisely to detect subtle effects, or consider biases stemming from failure to observe inbred offspring that die during early development. Analyses of multigenerational song sparrow (Melospiza melodia) pedigree data showed that most females had opportunity to increase or decrease the coefficient of inbreeding of their offspring through extra-pair reproduction with neighboring males. In practice, observed extra-pair offspring had lower inbreeding coefficients than females' within-pair offspring on average, while the probability of extra-pair reproduction increased substantially with the coefficient of kinship between a female and her socially paired male. However, simulations showed that such effects could simply reflect bias stemming from inbreeding depression in early offspring survival. The null hypothesis that extra-pair reproduction is random with respect to kinship therefore cannot be definitively rejected in song sparrows, and existing general evidence that females avoid inbreeding through extra-pair reproduction requires reevaluation given such biases. © 2014 The Author(s). Evolution © 2014 The Society for the Study of Evolution.

  15. Performance of Seven Tree Breeding Strategies Under Conditions of Inbreeding Depression.

    Science.gov (United States)

    Wu, Harry X; Hallingbäck, Henrik R; Sánchez, Leopoldo

    2016-01-06

    In the domestication and breeding of tree species that suffer from inbreeding depression (ID), the long-term performance of different breeding strategies is poorly known. Therefore, seven tree breeding strategies including single population, subline, selfing, and nucleus breeding were simulated using a multi-locus model with additive, partial, and complete dominance allele effects, and with intermediate, U-shaped, and major allele distributions. The strategies were compared for genetic gain, inbreeding accumulation, capacity to show ID, the frequencies and fixations of unfavorable alleles, and genetic variances in breeding and production populations. Measured by genetic gain of production population, the nucleus breeding and the single breeding population with mass selection strategies were equal or superior to subline and single breeding population with within-family selection strategies in all simulated scenarios, in spite of their higher inbreeding coefficients. Inbreeding and cross-breeding effectively decreased ID and could in some scenarios produce genetic gains during the first few generations. However, in all scenarios, considerable fixation of unfavorable alleles rendered the purging performance of selfing and cross-breeding strategies ineffective, and resulted in substantial inferiority in comparison to the other strategies in the long-term. Copyright © 2016 Wu et al.

  16. Inbreeding in the Seychelles warbler: environment-dependent maternal effects.

    Science.gov (United States)

    Richardson, David S; Komdeur, Jan; Burke, Terry

    2004-09-01

    The deleterious effects of inbreeding can be substantial in wild populations and mechanisms to avoid such matings have evolved in many organisms. In situations where social mate choice is restricted, extrapair paternity may be a strategy used by females to avoid inbreeding and increase offspring heterozygosity. In the cooperatively breeding Seychelles warbler, Acrocephalus sechellensis, neither social nor extrapair mate choice was used to avoid inbreeding facultatively, and close inbreeding occurred in approximately 5% of matings. However, a higher frequency of extra-group paternity may be selected for in female subordinates because this did reduce the frequency of mating between close relatives. Inbreeding resulted in reduced individual heterozygosity, which, against expectation, had an almost significant (P = 0.052), positive effect on survival. Conversely, low heterozygosity in the genetic mother was linked to reduced offspring survival, and the magnitude of this intergenerational inbreeding depression effect was environment-dependent. Because we controlled for genetic effects and most environmental effects (through the experimental cross-fostering of nestlings), we conclude that the reduced survival was a result of maternal effects. Our results show that inbreeding can have complicated effects even within a genetic bottlenecked population where the "purging" of recessive alleles is expected to reduce the effects of inbreeding depression.

  17. Second- and Higher-Order Virial Coefficients Derived from Equations of State for Real Gases

    Science.gov (United States)

    Parkinson, William A.

    2009-01-01

    Derivation of the second- and higher-order virial coefficients for models of the gaseous state is demonstrated by employing a direct differential method and subsequent term-by-term comparison to power series expansions. This communication demonstrates the application of this technique to van der Waals representations of virial coefficients.…

  18. Genomic Inbreeding and Relatedness in Wild Panda Populations.

    Directory of Open Access Journals (Sweden)

    John R Garbe

    Full Text Available Inbreeding and relatedness in wild panda populations are important parameters for panda conservation. Habitat loss and fragmentation are expected to increase inbreeding but the actual inbreeding levels in natural panda habitats were unknown. Using 150,025 SNPs and 14,926 SNPs selected from published whole-genome sequences, we estimated genomic inbreeding coefficients and relatedness of 49 pandas including 34 wild pandas sampled from six habitats. Qinling and Liangshan pandas had the highest levels of inbreeding and relatedness measured by genomic inbreeding and coancestry coefficients, whereas the inbreeding levels in Qionglai and Minshan were 28-45% of those in Qinling and Liangshan. Genomic coancestry coefficients between pandas from different habitats showed that panda populations from the four largest habitats, Minshan, Qionglai, Qinling and Liangshan, were genetically unrelated. Pandas between these four habitats on average shared 66.0-69.1% common alleles and 45.6-48.6% common genotypes, whereas pandas within each habitat shared 71.8-77.0% common alleles and 51.7-60.4% common genotypes. Pandas in the smaller populations of Qinling and Liangshan were more similarly to each other than pandas in the larger populations of Qionglai and Minshan according to three genomic similarity measures. Panda genetic differentiation between these habitats was positively related to their geographical distances. Most pandas separated by 200 kilometers or more shared no common ancestral alleles. The results provided a genomic quantification of the actual levels of inbreeding and relatedness among pandas in their natural habitats, provided genomic confirmation of the relationship between genetic diversity and geographical distances, and provided genomic evidence to the urgency of habitat protection.

  19. Genomic Inbreeding and Relatedness in Wild Panda Populations.

    Science.gov (United States)

    Garbe, John R; Prakapenka, Dzianis; Tan, Cheng; Da, Yang

    2016-01-01

    Inbreeding and relatedness in wild panda populations are important parameters for panda conservation. Habitat loss and fragmentation are expected to increase inbreeding but the actual inbreeding levels in natural panda habitats were unknown. Using 150,025 SNPs and 14,926 SNPs selected from published whole-genome sequences, we estimated genomic inbreeding coefficients and relatedness of 49 pandas including 34 wild pandas sampled from six habitats. Qinling and Liangshan pandas had the highest levels of inbreeding and relatedness measured by genomic inbreeding and coancestry coefficients, whereas the inbreeding levels in Qionglai and Minshan were 28-45% of those in Qinling and Liangshan. Genomic coancestry coefficients between pandas from different habitats showed that panda populations from the four largest habitats, Minshan, Qionglai, Qinling and Liangshan, were genetically unrelated. Pandas between these four habitats on average shared 66.0-69.1% common alleles and 45.6-48.6% common genotypes, whereas pandas within each habitat shared 71.8-77.0% common alleles and 51.7-60.4% common genotypes. Pandas in the smaller populations of Qinling and Liangshan were more similarly to each other than pandas in the larger populations of Qionglai and Minshan according to three genomic similarity measures. Panda genetic differentiation between these habitats was positively related to their geographical distances. Most pandas separated by 200 kilometers or more shared no common ancestral alleles. The results provided a genomic quantification of the actual levels of inbreeding and relatedness among pandas in their natural habitats, provided genomic confirmation of the relationship between genetic diversity and geographical distances, and provided genomic evidence to the urgency of habitat protection.

  20. Purging of inbreeding depression within the Irish Holstein-Friesian population

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    Mc Parland Sinéad

    2009-01-01

    Full Text Available Abstract The objective of this study was to investigate whether inbreeding depression in milk production or fertility performance has been partially purged due to selection within the Irish Holstein-Friesian population. Classical, ancestral (i.e., the inbreeding of an individual's ancestors according to two different formulae and new inbreeding coefficients (i.e., part of the classical inbreeding coefficient that is not accounted for by ancestral inbreeding were computed for all animals. The effect of each coefficient on 305-day milk, fat and protein yield as well as calving interval, age at first calving and survival to second lactation was investigated. Ancestral inbreeding accounting for all common ancestors in the pedigree had a positive effect on 305-day milk and protein yield, increasing yields by 4.85 kg and 0.12 kg, respectively. However, ancestral inbreeding accounting only for those common ancestors, which contribute to the classical inbreeding coefficient had a negative effect on all milk production traits decreasing 305-day milk, fat and protein yields by -8.85 kg, -0.53 kg and -0.33 kg, respectively. Classical, ancestral and new inbreeding generally had a detrimental effect on fertility and survival traits. From this study, it appears that Irish Holstein-Friesians have purged some of their genetic load for milk production through many years of selection based on production alone, while fertility, which has been less intensely selected for in the population demonstrates no evidence of purging.

  1. Extending reversed-flow chromatographic methods for the measurement of diffusion coefficients to higher temperatures.

    Science.gov (United States)

    McGivern, W Sean; Manion, Jeffrey A

    2011-11-18

    A reversed-flow gas-chromatography (RF-GC) apparatus for the measurement of binary diffusion coefficients is described and utilized to measure the binary diffusion coefficients for several systems at temperatures from (300 to 723)K. Hydrocarbons are detected using flame ionization detection, and inert species can be detected by thermal conductivity. The present apparatus has been utilized to measure diffusion coefficients at substantially higher temperatures than previous RF-GC work. Characterization of the new apparatus was accomplished by comparing measured binary diffusion coefficients of dilute argon in helium to established reference values. Further diffusion coefficient measurements for dilute helium in argon and dilute nitrogen in helium (using thermal conductivity detection) and dilute methane in helium (using flame ionization detection) were performed and found to be in excellent agreement with literature values. The measurement of these well-established diffusion coefficients has shown that specific experimental conditions are required for accurate diffusion measurements using this technique, particularly at higher temperatures. Numerical simulations of the diffusion experiments are presented to demonstrate that artifacts of the analysis procedure must be specifically identified to ensure accuracy, particularly at higher temperatures. Published by Elsevier B.V.

  2. When not to avoid inbreeding.

    Science.gov (United States)

    Kokko, Hanna; Ots, Indrek

    2006-03-01

    Avoidance of incestuous matings is widely reported across many animal taxa, and the adaptive value of such behavior is explained through inbreeding depression. However, an old and somewhat neglected theoretical result predicts that inbred matings offer another, positive effect on the inclusive fitness of parents: an individual who mates with a relative will help that relative to spread genes identical by descent. This benefit can be substantial, if the additional mating achieved by the relative does not harm his mating success otherwise, and in the context of selfing in plants the phenomenon is well known. Here, we develop a model that derives expected values of inbreeding tolerance, that is, the magnitude of inbreeding depression that is required to make individuals avoid inbreeding, for different animal life histories and parental investment patterns. We also distinguish between simultaneous and sequential mate choice, and show that inbreeding tolerance should often be remarkably high in the latter scenario in particular, although egalitarian parental care will lead to lower tolerance. There is a mismatch between theory and data: the almost complete lack of cases where individuals prefer to mate incestuously is at odds with a large overlap between the predicted range of inbreeding tolerance and estimates of inbreeding depression found in nature. We discuss four different solutions to this enigma, and suggest that inbreeding tolerance, where it is found, should not always be attributed to a simple constraint that has prevented finding any other mate.

  3. No evidence of inbreeding depression in sperm performance traits in wild song sparrows.

    Science.gov (United States)

    Losdat, Sylvain; Germain, Ryan R; Nietlisbach, Pirmin; Arcese, Peter; Reid, Jane M

    2018-02-01

    Inbreeding is widely hypothesized to shape mating systems and population persistence, but such effects will depend on which traits show inbreeding depression. Population and evolutionary consequences could be substantial if inbreeding decreases sperm performance and hence decreases male fertilization success and female fertility. However, the magnitude of inbreeding depression in sperm performance traits has rarely been estimated in wild populations experiencing natural variation in inbreeding. Further, the hypothesis that inbreeding could increase within-ejaculate variation in sperm traits and thereby further affect male fertilization success has not been explicitly tested. We used a wild pedigreed song sparrow ( Melospiza melodia ) population, where frequent extrapair copulations likely create strong postcopulatory competition for fertilization success, to quantify effects of male coefficient of inbreeding ( f ) on key sperm performance traits. We found no evidence of inbreeding depression in sperm motility, longevity, or velocity, and the within-ejaculate variance in sperm velocity did not increase with male f . Contrary to inferences from highly inbred captive and experimental populations, our results imply that moderate inbreeding will not necessarily constrain sperm performance in wild populations. Consequently, the widely observed individual-level and population-level inbreeding depression in male and female fitness may not stem from reduced sperm performance in inbred males.

  4. Estimating inbreeding rates in natural populations: Addressing the problem of incomplete pedigrees

    Science.gov (United States)

    Miller, Mark P.; Haig, Susan M.; Ballou, Jonathan D.; Steel, E. Ashley

    2017-01-01

    Understanding and estimating inbreeding is essential for managing threatened and endangered wildlife populations. However, determination of inbreeding rates in natural populations is confounded by incomplete parentage information. We present an approach for quantifying inbreeding rates for populations with incomplete parentage information. The approach exploits knowledge of pedigree configurations that lead to inbreeding coefficients of F = 0.25 and F = 0.125, allowing for quantification of Pr(I|k): the probability of observing pedigree I given the fraction of known parents (k). We developed analytical expressions under simplifying assumptions that define properties and behavior of inbreeding rate estimators for varying values of k. We demonstrated that inbreeding is overestimated if Pr(I|k) is not taken into consideration and that bias is primarily influenced by k. By contrast, our new estimator, incorporating Pr(I|k), is unbiased over a wide range of values of kthat may be observed in empirical studies. Stochastic computer simulations that allowed complex inter- and intragenerational inbreeding produced similar results. We illustrate the effects that accounting for Pr(I|k) can have in empirical data by revisiting published analyses of Arabian oryx (Oryx leucoryx) and Red deer (Cervus elaphus). Our results demonstrate that incomplete pedigrees are not barriers for quantifying inbreeding in wild populations. Application of our approach will permit a better understanding of the role that inbreeding plays in the dynamics of populations of threatened and endangered species and may help refine our understanding of inbreeding avoidance mechanisms in the wild.

  5. Rate of inbreeding and effective population size in four major South ...

    African Journals Online (AJOL)

    Pedigree information on the registered South African Ayrshire (n = 47 116), Guernsey (n = 18 766), Holstein (n = 892 458) and Jersey (n = 314 403) breeds was analyzed to determine the rate of inbreeding and effective population sizes for the period 1960 to 2003. Inbreeding coefficients were calculated using the Animal ...

  6. Evaluation of Optimum Genetic Contribution Theory to Control Inbreeding While Maximizing Genetic Response

    Directory of Open Access Journals (Sweden)

    S.-H. Oh

    2012-03-01

    Full Text Available Inbreeding is the mating of relatives that produce progeny having more homozygous alleles than non-inbred animals. Inbreeding increases numbers of recessive alleles, which is often associated with decreased performance known as inbreeding depression. The magnitude of inbreeding depression depends on the level of inbreeding in the animal. Level of inbreeding is expressed by the inbreeding coefficient. One breeding goal in livestock is uniform productivity while maintaining acceptable inbreeding levels, especially keeping inbreeding less than 20%. However, in closed herds without the introduction of new genetic sources high levels of inbreeding over time are unavoidable. One method that increases selection response and minimizes inbreeding is selection of individuals by weighting estimated breeding values with average relationships among individuals. Optimum genetic contribution theory (OGC uses relationships among individuals as weighting factors. The algorithm is as follows: i Identify the individual having the best EBV; ii Calculate average relationships ( r j ¯ between selected and candidates; iii Select the individual having the best EBV adjusted for average relationships using the weighting factor k, E B V * = E B V j ( 1 - k r j ¯ . iv Repeat process until the number of individuals selected equals number required. The objective of this study was to compare simulated results based on OGC selection under different conditions over 30 generations. Individuals (n = 110 were generated for the base population with pseudo random numbers of N~ (0, 3, ten were assumed male, and the remainder female. Each male was mated to ten females, and every female was assumed to have 5 progeny resulting in 500 individuals in the following generation. Results showed the OGC algorithm effectively controlled inbreeding and maintained consistent increases in selection response. Difference in breeding values between selection with OGC algorithm and by EBV only was 8

  7. Challenges in inbreeding estimation of large populations based on Polish Holstein-Friesian cattle pedigree.

    Science.gov (United States)

    Sell-Kubiak, Ewa; Czarniecki, Łukasz; Strabel, Tomasz

    2018-04-11

    The aim of this study was to evaluate observed and future inbreeding level in Polish Holstein-Friesian cattle population. In total, over 9.8 mln animals were used in the analysis coming from the pedigree of Polish Federation of Cattle Breeders and Dairy Farmers. Inbreeding level, as an average per birth year, was estimated with the method accounting for missing parent information with the assumption of year 1950 as the base year of the population. If an animal had no ancestral records, an average inbreeding level from its birth year was assigned. Twice the average inbreeding level served as relatedness of the animal to the population, which enabled estimation of inbreeding in its offspring. The future inbreeding of potential offspring was estimated as an average of animals (bulls and cows) available for mating in a certain year. It was observed that 30-50% of animals born between 1985 and 2015 had no relevant ancestral information, which is caused by a high number of new animals and/or entire farms entering the national milk recordings. For the year 2015, the observed inbreeding level was 3.30%, which was more than twice the inbreeding with the classical approach (without missing parent information) and higher by 0.4% than the future inbreeding. The average increase of inbreeding in years 2010-2015 was 0.10%, which is similar to other countries monitored by World Holstein-Friesian Federation. However, the values might be underestimated due to low pedigree completeness. The estimates of future inbreeding suggested that observed inbreeding could be even lower and also increase slower, which indicates a constant need to monitor rate of increase in inbreeding over time. The most important aspect of presented results is the necessity to advise individual farmers to keep precise recordings of the matings on their farm in order to improve the pedigree completeness of Polish Holstein-Friesian and to use suitable mating programs to avoid too rapid growth of inbreeding.

  8. Pedigree analysis and inbreeding effects over morphological traits in Campolina horse population.

    Science.gov (United States)

    Bussiman, F O; Perez, B C; Ventura, R V; Peixoto, M G C D; Curi, R A; Balieiro, J C C

    2018-02-22

    Genetic improvement, without control of inbreeding, can go to loss of genetic variability, reducing the potential for genetic gains in the domestic populations. The aim of this study was to analyze the population structure and the inbreeding depression in Campolina horses. Phenotype information from 43 465 individuals was analyzed, data provided by the Campolina Breeders Association. A pedigree file containing 107 951 horses was used to connected the phenotyped individuals. The inbreeding coefficient was performed by use of the diagonal of the relationship matrix and the genealogical parameters were computed using proper softwares. The effective population size was estimated based on the rate of inbreeding and census information, and the stratification of the population was verified by the average relationship coefficient between animals born in different regions of Brazil. The effects of inbreeding on morphological traits were made by the use of inbreeding coefficient as a covariate in the model of random regression. The inbreeding coefficient increased from 1990 on, impacting effective population size and, consequently, shrinking genetic variability. The paternal inbreeding was greater than maternal, which may be attributed to the preference for inbred animals in reproduction. The average genetic relationship coefficient of animals born in different states was lower than individuals born within the same state. The increase in the inbreeding coefficient was negatively associated with all studied traits, showing the importance to avoid genetic losses in the long term. Although results do not indicate a severe narrowing of the population until the present date, the average relationship coefficient shows signs of increase, which could cause a drastic reduction in genetic variability if inbred mating is not successfully controlled in the Campolina horse population.

  9. Impact of consanguineous marriages and degrees of inbreeding on fertility, child mortality, secondary sex ratio, selection intensity, and genetic load: a cross-sectional study from Northern India.

    Science.gov (United States)

    Fareed, Mohd; Kaisar Ahmad, Mir; Azeem Anwar, Malik; Afzal, Mohammad

    2017-01-01

    The aim of our study was to understand the relationship between consanguineous marriages and reproductive outcomes. A total of 999 families were recruited from five Muslim populations of Jammu region. Family pedigrees were drawn to access the family history and inbreeding status in terms of coefficient of inbreeding (F). Fertility, mortality, secondary sex ratio, selection intensity, and lethal equivalents were measured using standard methods. The significant differences for gross fertility was found to be higher among inbred groups as compared to the unrelated families (P child mortality rates (i.e., U5MR and U18MR) have presented a persuasive increase with an upsurge in the homozygosity level. The mortality rate was found to be maximum among families with the highest value of coefficient of inbreeding (F). The selection intensity (SI) also showed inflations among families with respect to their increasing inbreeding coefficients. The greater values of lethal equivalents per gamete (LEs/gamete) were observed for autosomal inheritance in comparison with sex-linked inheritance. Our conclusive assessment brings out the deleterious consequence of consanguineous marriages on reproductive outcomes.

  10. Revealing gene action for production characteristics by inbreeding ...

    African Journals Online (AJOL)

    inbreeding coefficient on the mean of the characters in a two-way selection experiment for the slope (b) and intercept. (Ln (a)) of the ... ln (a) selection group, as well as average daily f-eed intake (Phase I and 2) of the b selection group. Die genewerking wat ..... exposed to natural selection for an extended period under con-.

  11. On individual-specific prediction of hidden inbreeding depression load.

    Science.gov (United States)

    Casellas, J

    2018-02-01

    Inbreeding depression is caused by increased homozygosity in the genome and merges two genetic mechanisms, a higher impact from recessive mutations and the waste of overdominance contributions. It is of major concern for the conservation of endangered populations of plants and animals, as major abnormalities are more frequent in inbred families than in outcrosses. Nevertheless, we lack appropriate analytical methods to estimate the hidden inbreeding depression load (IDL) in the genome of each individual. Here, a new mixed linear model approach has been developed to account for the inbreeding depression-related background of each individual in the pedigree. Within this context, inbred descendants contributed relevant information to predict the IDL contained in the genome of a given ancestor; moreover, known relationships spread these predictions to the remaining individuals in the pedigree, even if not contributing inbred offspring. Results obtained from the analysis of weaning weight in the MARET rabbit population demonstrated that the genetic background of inbreeding depression distributed heterogeneously across individuals and inherited generation by generation. Moreover, this approach was clearly preferred in terms of model fit and complexity when compared with classical approaches to inbreeding depression. This methodology must be viewed as a new tool for a better understanding of inbreeding in domestic and wild populations. © 2017 Blackwell Verlag GmbH.

  12. THE APPLICATION OF RAPD FINGERPRINTING TO ASSESS INBREEDING LEVELS IN THE CULTURED POPULATIONS OF GIANT FRESHWATER PRAWN, Macrobrachium rosenbergii

    Directory of Open Access Journals (Sweden)

    Imron Imron

    2010-06-01

    Full Text Available Inbreeding has been one of central issues with regard to genetic quality of aquaculture species, including giant fresh water prawn (GFP. Conventional methods for the estimation of inbreeding level are available, such as pedigree analyses which requires a good pedigree record which, unfortunately, is rarely available. Likewise, microsatellite molecular markers commonly applied to obtain the coefficient inbreeding estimates are both laborious and expensive. Hence, an alternative method of inbreeding assessment which is relatively easy but reliable is in need. This study was aimed to explore the applicability of RAPD fingerprinting, which is known to be simple and affordable, to estimate inbreeding level of GFP population. Three GFP populations namely inbred, outbred, and farm populations with inbreeding level of 25%, 0%, and unknown, respectively, were genotyped using five polymorphic RAPD primers. The inbreeding levels mentioned within the first two populations were determined using pedigree analysis. RAPD banding patterns were then used to calculate band sharing index (BSI and inbreeding coefficient (F. Assessment of the applicability of inbreeding level estimates obtained by RAPD markers was performed by comparing them to those estimated by pedigree analysis. Results show that RAPD fingerprinting was capable of delineating populations differing in their inbreeding coefficients. The pattern resulted from molecular inbreeding coefficient within the inbred and outbred groups, was congruent with that shown by pedigree analysis, while the farm population showed closeness to the inbred group. While the accuracy of the estimate needs to be verified further, this study suggests that RAPD fingerprinting is applicable to estimate population inbreeding level, particularly due to its technical simplicity and cost affordability.

  13. Academic Inbreeding: Exploring Its Characteristics and Rationale in Japanese Universities Using a Qualitative Perspective

    Science.gov (United States)

    Horta, Hugo; Sato, Machi; Yonezawa, Akiyoshi

    2011-01-01

    This study analyses why and how academic inbreeding as a recruitment practice continues to prevail in Japan, a country with a mature higher education system, where high rates of academic inbreeding endure in most of the research-oriented universities in spite of several higher education reforms. Based on a qualitative analysis, we disclose three…

  14. Métodos de estimação do coeficiente de endogamia em uma população diplóide com alelos múltiplos Methods of estimation of the inbreeding coefficient in a diploid population with multiple alleles

    Directory of Open Access Journals (Sweden)

    Joel Augusto Muniz

    2008-02-01

    Full Text Available Com o presente trabalho, objetivou-se avaliar as propriedades de três estimadores do coeficiente de endogamia, F, em uma população diplóide com alelos múltiplos, por meio de dados de frequências alélicas de amostras de indíviduos, obtidas em populações simuladas, por meio do SAS. Foram avaliados o estimador de F, obtido pela média das estimativas nas análises de cada alelo, o estimador considerando a análise conjunta envolvendo todos os alelos, bem como aquele por meio de análise multivariada com os três alelos proposto por Long (1986. Os resultados encontrados para a média e variância dos estimadores, a partir de 1000 estimativas de F, calculadas para cada tamanho de amostra, mostraram que os três estimadores são tendenciosos. Entretanto, de maneira geral, observou-se que o estimador considerando a análise de variância conjunta foi menos tendencioso e apresentou menor variância, quando o coeficiente de endogamia na população era alto, enquanto que para populações com endogamia baixa a variância do estimador considerando a análise multivariada foi menor.The present work evaluted the properties of three estimators of the inbreeding coefficient, F, in a diploid population with multiple alleles, using data of gene frequencies in individuals from random samples, obtained in simulate populations, through the SAS. Were evaluted the estimator of F, obtained by single and joint univariate analysis and the estimator of F obtained by multivariate analysis as proposed by Long (1986. The analysis of the means and variances of the estimators, obtained of 1000 estimates of F, calculated for each sample size, it demonstrated that the three estimators is bias. However, it was observed that the estimator obtained of univariate analysis it was less biased and it presented smaller variance, when the inbreeding coefficient in the population was elevated, while for populations with low inbreeding, the variance of, the estimator obtained

  15. Measurements of elliptic flow and higher-order Fourier coefficients with the ATLAS experiment

    CERN Document Server

    Jia, J; The ATLAS collaboration

    2011-01-01

    We report the measurements of collective harmonic flow coefficients $v_n$ for $n=2-6$ in Pb+Pb collisions at sqrt(s_NN)=2.76 TeV with the ATLAS detector. They are extracted via an event plane method based on the ATLAS Forward Calorimeter over a broad range in $p_T$, $eta$ and centrality. The $v_n$ coefficients are found to change weakly within $|eta|<2.5$ and all with the same qualitative trend as a function of $p_T$: all rise up to 3-4 GeV, and then fall towards higher $p_T$. The high statistical precision of the $v_2$ term, allow us to clearly determine its trend out to 20 GeV for a broad centrality classes. The same harmonic flow coefficients are also obtained via a Fourier analysis of the two-particle $Deltaphi-Deltaeta$ correlation with a large $Deltaeta$ gap. A detailed comparison with the event plane method allow us to determine the regions of the two-particle phase space (in $p_T$ and $Deltaeta$ and centrality), in which the collective phenomena play a dominating role. The physics implications ...

  16. Inferência Bayesiana na análise genética de populações diplóides: estimação do coeficiente de endogamia e da taxa de fecundação cruzada Bayesian inference in genetic analysis of diploid populations: inbreeding coefficient and outcrossing rate estimation

    Directory of Open Access Journals (Sweden)

    Ricardo Luis dos Reis

    2008-08-01

    Full Text Available Neste estudo, utilizou-se a metodologia Bayesiana para estimar o coeficiente de endogamia e a taxa de fecundação cruzada de uma população diplóide por meio do modelo aleatório de COCKERHAM para freqüências alélicas. Um sistema de simulação de dados foi estruturado para validar a metodologia utilizada. O algoritmo Gibbs Sampler foi implementado no software R para obter amostras das distribuições marginais a posteriori para o coeficiente de endogamia e para a taxa de fecundação. O método Bayesiano mostrou-se eficiente na estimação dos parâmetros, pois os valores paramétricos utilizados na simulação encontravam-se dentro do intervalo de credibilidade de 95% em todos os cenários considerados. A convergência do algoritmo Gibbs Sampler foi verificada, validando assim os resultados obtidos.The Bayesian methodology was used to estimate the inbreeding coefficient and outcrossing rate in diploid populations by COCKERHAM random model to allelic frequency. The proposed methodology was evaluated by data simulation. The Gibbs Sampler algorithm was implemented in the R statistical software to obtain the random samples of the inbreeding coefficient and outcrossing rate posteriors marginal distributions. The Bayesian method showed good results, because the 95% credible intervals contained the true parameter values to all of the selected scenes. The Gibbs Sampler convergence was checked and this validated the estimation results.

  17. Academic Inbreeding in the Portuguese Academia

    Science.gov (United States)

    Tavares, Orlanda; Cardoso, Sónia; Carvalho, Teresa; Sousa, Sofia Branco; Santiago, Rui

    2015-01-01

    This paper analyses the inbreeding phenomena in Portuguese public universities. Inbreeding is defined as the recruitment of academics by the same institution that awarded their PhDs. Focusing on 1,217 PhD-holding Portuguese academics, belonging to four public universities and to six disciplinary areas, inbreeding is analysed in order to understand…

  18. Inbreeding among pen-reared quail

    Science.gov (United States)

    Nestler, R.B.; Nelson, A.L.

    1945-01-01

    The effect of inbreeding in wildlife species has received attention from several sources. Recently the 'inbreeding theory' as a possible explanation of cycles in game populations was given careful consideration by a group of wildlife experts and geneticists. Scott's symposium (1944) consisting of comments received from eight authorities revealed unanimity in a decision that inbreeding is not the causative factor.

  19. Inbreeding effects on in vitro embryo production traits in Guzerá cattle.

    Science.gov (United States)

    Perez, B C; Balieiro, J C C; Ventura, R V; Bruneli, F A T; Peixoto, M G C D

    2017-11-01

    Inbreeding has been associated with the impairment of reproductive performance in many cattle breeds. Although the usage of reproductive biotechnologies has been increasing in bovine populations, not much attention has been given to the impact of inbreeding over cow's performance on artificial reproduction. The objective of this study was to estimate the impact of inbreeding on in vitro embryo production in a Guzerá breed population. The inbreeding coefficient (F), calculated as half of the co-ancestry of the individual's parents, was used as an estimate of inbreeding. The inbreeding coefficients of the donor, sire (used on in vitro fertilization) and of the embryos were included, separately, in the proposed models either as classificatory or continuous variables (linear and quadratic effects). The percentage of non-inbred individuals (or embryos) and mean F of donors, embryos and sires were 29.38%; 35.76%; 42.86% and 1.98±2.68; 1.32±3.13; 2.08±2.79, respectively. Two different models were considered, one for oocyte production traits and other for embryo production traits. The increase of F of the donor significantly (P0.05) effects were observed for the sire (father of the embryos) inbreeding coefficient over the traits analysed. Embryo's F influenced (Pproduction may, in the long-term, have negative implications on the number of embryos obtained per cow and increase the relative costs of the improvement programmes based on this technology. High levels of inbreeding should be avoided when selecting Guzerá female donors and planning in vitro fertilization mating.

  20. Genetic diversity, inbreeding and cancer.

    Science.gov (United States)

    Ujvari, Beata; Klaassen, Marcel; Raven, Nynke; Russell, Tracey; Vittecoq, Marion; Hamede, Rodrigo; Thomas, Frédéric; Madsen, Thomas

    2018-03-28

    Genetic diversity is essential for adaptive capacities, providing organisms with the potential of successfully responding to intrinsic and extrinsic challenges. Although a clear reciprocal link between genetic diversity and resistance to parasites and pathogens has been established across taxa, the impact of loss of genetic diversity by inbreeding on the emergence and progression of non-communicable diseases, such as cancer, has been overlooked. Here we provide an overview of such associations and show that low genetic diversity and inbreeding associate with an increased risk of cancer in both humans and animals. Cancer being a multifaceted disease, loss of genetic diversity can directly (via accumulation of oncogenic homozygous mutations) and indirectly (via increased susceptibility to oncogenic pathogens) impact abnormal cell emergence and escape of immune surveillance. The observed link between reduced genetic diversity and cancer in wildlife may further imperil the long-term survival of numerous endangered species, highlighting the need to consider the impact of cancer in conservation biology. Finally, the somewhat incongruent data originating from human studies suggest that the association between genetic diversity and cancer development is multifactorial and may be tumour specific. Further studies are therefore crucial in order to elucidate the underpinnings of the interactions between genetic diversity, inbreeding and cancer. © 2018 The Author(s).

  1. Inbreeding, microsatellite heterozygosity, and morphological traits in Lipizzan horses.

    Science.gov (United States)

    Curik, I; Zechner, P; Sölkner, J; Achmann, R; Bodo, I; Dovc, P; Kavar, T; Marti, E; Brem, G

    2003-01-01

    While the negative effects of inbreeding and reduced heterozygosity on fecundity and survival are well established, only a few investigations have been carried out concerning their influence on morphological traits. This topic is of particular interest for a small and closed population such as the Lipizzan horse. Thus, 27 morphological traits were measured in 360 Lipizzan mares and were regressed on the individual inbreeding coefficients, as well as on the individual heterozygosity and mean squared distances (mean d(2)) between microsatellite alleles within an individual. Both individual heterozygosity and mean d(2) were based on 17 microsatellite loci dispersed over 14 chromosomes. The results obtained by multivariate analysis reveal significant effects of stud (P morphological traits were observed in the Lipizzan horse.

  2. The influence of dispersion slope to the higher-order dispersion coefficients for highly-nonlinear fibers

    Science.gov (United States)

    Othman, N.; Shah, N. S. M.; Tay, K. G.; Pakarzadeh, H.; Cholan, N. A.; Talib, R.

    2017-09-01

    The highly-nonlinear fiber is the ideal gain medium for many applications particularly because its dispersion can be easily engineered. However, the modification of the fiber dispersion will affect the higher-order dispersion coefficients. Hence, this paper investigates the effect of highly-nonlinear dispersion-shifted fiber dispersion profile on the higher-order dispersion coefficients which are the fourth-order and sixth-order dispersion coefficients. The dispersion profile was modified by varying the slope at zero-dispersion wavelength. The fourth-order dispersion coefficient exhibits changes from positive to negative value as the slope at zero-dispersion wavelength is getting higher. Meanwhile, sixth-order dispersion coefficient remains with the positive value even though it shows the reduction as the slope is increased, however it will eventually become negative when the dispersion is high enough. In short, the values of both fourth-order and sixth-order dispersion coefficients at zero-dispersion wavelength decrease when the slope increases. At the request of all authors of the paper, an updated version of this article was published on 13 October 2017. The original version supplied to AIP Publishing had an incorrect affiliation for R. Talib. The affiliation for R. Talib was changed from 3Shiraz University of Technology to 1Universiti Tun Hussein Onn Malaysia. This has been corrected in the updated and re-published version.

  3. Research on inbreeding in the 'omic' era

    DEFF Research Database (Denmark)

    Kristensen, Torsten N; Pedersen, Kamilla S; Vermeulen, Cornelis J

    2010-01-01

    Developments in molecular and systems biology have enabled novel approaches to be used in the study of inbreeding. Mechanistic and functional studies using ‘omic' technologies can increase the understanding of the consequences of inbreeding, from the level of DNA to that of population growth...

  4. The effect of fast created inbreeding on litter size and body weights in mice

    Directory of Open Access Journals (Sweden)

    Meuwissen Theo

    2005-09-01

    Full Text Available Abstract This study was designed to reveal any differences in effects of fast created versus total inbreeding on reproduction and body weights in mice. A line selected for large litter size for 124 generations (H and a control line (K maintained without selection for the same number of generations were crossed (HK and used as a basis for the experiment. Within the HK cross, full sib, cousin or random mating were practised for two generations in order to create new inbreeding (IBF at a fast rate. In the first generation of systematic mating, old inbreeding was regenerated in addition to creation of new inbreeding from the mating design giving total inbreeding (IBT. The number of pups born alive (NBA and body weights of the animals were then analysed by a model including both IBT and IBF. The IBT of the dam was in the present study found to reduce the mean NBA with -0.48 (± 0.22 (p F was -0.42 (± 0.27. For the trait NBA per female mated, the effect of IBT was estimated to be -0.45 (± 0.29 per 10% increase in the inbreeding coefficient and the effect of IBF was -0.90 (± 0.37 (p F of the dam could be found on sex-ratio and body weights at three and six weeks of age in a population already adjusted for IBT.

  5. EFFECT OF INBREEDING ON PRE-WEANING GROWTH TRAITS IN THALLI SHEEP

    Directory of Open Access Journals (Sweden)

    A. HUSSAIN, P. AKHTAR, S. ALI, M. YOUNAS1 AND M. SHAFIQ2

    2006-07-01

    Full Text Available Pedigree records of 17250 Thalli sheep with 17030 lambings maintained at the Livestock Experiment Station, Rakh Ghulaman, Distt. Bhakkar, Pakistan during the period from 1975 to 2004 were utilized in the present study. Average values for birth weight, weights at 60 and 90 days of age, weaning weight and pre-weaning average daily gain were 4.11 ± 0.82, 11.58 ± 3.57, 14.92 ± 4.56, 18.95 ± 4.56 and 0.12 ± 0.04 kg, respectively. Coefficients of inbreeding ranged from 10.15 to 37.50 percent for 295 animals, being 1.70 percent of the flock. Inbreeding significantly (P<0.01 affected birth and 60 days weight. Birth weight and 60 days weight decreased by 0.051 and 0.048 kg for each 1 percent increase in the level of inbreeding. However, inbreeding had non significant effect on weight at 90 days of age, weaning weight and pre-weaning average daily gain. The regression values for these traits were 0.010, 0.083 and 0.105, respectively. It was concluded that inbreeding showed deleterious effects only in early stages of life but as the lambs grew older the effect of inbreeding on pre-weaning traits diminished.

  6. Better Fitness in Captive Cuvier’s Gazelle despite Inbreeding Increase: Evidence of Purging?

    Science.gov (United States)

    Moreno, Eulalia; Pérez-González, Javier; Carranza, Juan; Moya-Laraño, Jordi

    2015-01-01

    Captive breeding of endangered species often aims at preserving genetic diversity and to avoid the harmful effects of inbreeding. However, deleterious alleles causing inbreeding depression can be purged when inbreeding persists over several generations. Despite its great importance both for evolutionary biology and for captive breeding programmes, few studies have addressed whether and to which extent purging may occur. Here we undertake a longitudinal study with the largest captive population of Cuvier's gazelle managed under a European Endangered Species Programme since 1975. Previous results in this population have shown that highly inbred mothers tend to produce more daughters, and this fact was used in 2006 to reach a more appropriate sex-ratio in this polygynous species by changing the pairing strategy (i.e., pairing some inbred females instead of keeping them as surplus individuals in the population). Here, by using studbook data we explore whether purging has occurred in the population by investigating whether after the change in pairing strategy a) inbreeding and homozygosity increased at the population level, b) fitness (survival) increased, and c) the relationship between inbreeding and juvenile survival, was positive. Consistent with the existence of purging, we found an increase in inbreeding coefficients, homozygosity and juvenile survival. In addition, we showed that in the course of the breeding programme the relationship between inbreeding and juvenile survival was not uniform but rather changed over time: it was negative in the early years, flat in the middle years and positive after the change in pairing strategy. We highlight that by allowing inbred individuals to mate in captive stocks we may favour sex-ratio bias towards females, a desirable managing strategy to reduce the surplus of males that force most zoos to use ethical culling and euthanizing management tools. We discuss these possibilities but also acknowledge that many other effects

  7. Better Fitness in Captive Cuvier's Gazelle despite Inbreeding Increase: Evidence of Purging?

    Directory of Open Access Journals (Sweden)

    Eulalia Moreno

    Full Text Available Captive breeding of endangered species often aims at preserving genetic diversity and to avoid the harmful effects of inbreeding. However, deleterious alleles causing inbreeding depression can be purged when inbreeding persists over several generations. Despite its great importance both for evolutionary biology and for captive breeding programmes, few studies have addressed whether and to which extent purging may occur. Here we undertake a longitudinal study with the largest captive population of Cuvier's gazelle managed under a European Endangered Species Programme since 1975. Previous results in this population have shown that highly inbred mothers tend to produce more daughters, and this fact was used in 2006 to reach a more appropriate sex-ratio in this polygynous species by changing the pairing strategy (i.e., pairing some inbred females instead of keeping them as surplus individuals in the population. Here, by using studbook data we explore whether purging has occurred in the population by investigating whether after the change in pairing strategy a inbreeding and homozygosity increased at the population level, b fitness (survival increased, and c the relationship between inbreeding and juvenile survival, was positive. Consistent with the existence of purging, we found an increase in inbreeding coefficients, homozygosity and juvenile survival. In addition, we showed that in the course of the breeding programme the relationship between inbreeding and juvenile survival was not uniform but rather changed over time: it was negative in the early years, flat in the middle years and positive after the change in pairing strategy. We highlight that by allowing inbred individuals to mate in captive stocks we may favour sex-ratio bias towards females, a desirable managing strategy to reduce the surplus of males that force most zoos to use ethical culling and euthanizing management tools. We discuss these possibilities but also acknowledge that many

  8. The effects of age and environment on the expression of inbreeding depression in Eucalyptus globulus

    Science.gov (United States)

    Costa e Silva, J; Hardner, C; Tilyard, P; Potts, B M

    2011-01-01

    Inbreeding adversely affects fitness traits in many plant and animal species, and the magnitude, stability and genetic basis of inbreeding depression (ID) will have short- and long-term evolutionary consequences. The effects of four degrees of inbreeding (selfing, f=50% full- and half-sib matings, f=25 and 12.5% and unrelated outcrosses, f=0%) on survival and growth of an island population of Eucalyptus globulus were studied at two sites for over 14 years. For selfs, ID in survival increased over time, reaching a maximum of 49% by age 14 years. However, their inbreeding depression for stem diameter remained relatively stable with age, and ranged from 28 to 36% across years and sites. ID for survival was markedly greater on the more productive site, possibly due to greater and earlier onset of inter-tree competition, but was similar on both sites for the diameter of survivors. The deleterious trait response to increasing inbreeding coefficients was linear for survival and diameter. Non-significant quadratic effects suggested that epistasis did not contribute considerably to the observed ID at the population level. Among- and within-family coefficients of variation for diameter increased with inbreeding degree, and the variance among the outcrossed families was significant only on the more productive site. The performance of self-families for diameter was highly stable between sites. This suggests that, for species with mixed mating systems, environmentally stable inbreeding effects in open-pollinated progenies may tend to mask the additive genotype-by-environment interaction for fitness traits and the adaptive response to the environment. PMID:21224873

  9. Inbreeding alters activities of the stress-related enzymes chitinases and β-1,3-glucanases.

    Science.gov (United States)

    Leimu, Roosa; Kloss, Lena; Fischer, Markus

    2012-01-01

    Pathogenesis-related proteins, chitinases (CHT) and β-1,3-glucanases (GLU), are stress proteins up-regulated as response to extrinsic environmental stress in plants. It is unknown whether these PR proteins are also influenced by inbreeding, which has been suggested to constitute intrinsic genetic stress, and which is also known to affect the ability of plants to cope with environmental stress. We investigated activities of CHT and GLU in response to inbreeding in plants from 13 Ragged Robin (Lychnis flos-cuculi) populations. We also studied whether activities of these enzymes were associated with levels of herbivore damage and pathogen infection in the populations from which the plants originated. We found an increase in pathogenesis-related protein activity in inbred plants from five out of the 13 investigated populations, which suggests that these proteins may play a role in how plants respond to intrinsic genetic stress brought about by inbreeding in some populations depending on the allele frequencies of loci affecting the expression of CHT and the past levels of inbreeding. More importantly, we found that CHT activities were higher in plants from populations with higher levels of herbivore or pathogen damage, but inbreeding reduced CHT activity in these populations disrupting the increased activities of this resistance-related enzyme in populations where high resistance is beneficial. These results provide novel information on the effects of plant inbreeding on plant-enemy interactions on a biochemical level.

  10. Inbreeding alters activities of the stress-related enzymes chitinases and β-1,3-glucanases.

    Directory of Open Access Journals (Sweden)

    Roosa Leimu

    Full Text Available Pathogenesis-related proteins, chitinases (CHT and β-1,3-glucanases (GLU, are stress proteins up-regulated as response to extrinsic environmental stress in plants. It is unknown whether these PR proteins are also influenced by inbreeding, which has been suggested to constitute intrinsic genetic stress, and which is also known to affect the ability of plants to cope with environmental stress. We investigated activities of CHT and GLU in response to inbreeding in plants from 13 Ragged Robin (Lychnis flos-cuculi populations. We also studied whether activities of these enzymes were associated with levels of herbivore damage and pathogen infection in the populations from which the plants originated. We found an increase in pathogenesis-related protein activity in inbred plants from five out of the 13 investigated populations, which suggests that these proteins may play a role in how plants respond to intrinsic genetic stress brought about by inbreeding in some populations depending on the allele frequencies of loci affecting the expression of CHT and the past levels of inbreeding. More importantly, we found that CHT activities were higher in plants from populations with higher levels of herbivore or pathogen damage, but inbreeding reduced CHT activity in these populations disrupting the increased activities of this resistance-related enzyme in populations where high resistance is beneficial. These results provide novel information on the effects of plant inbreeding on plant-enemy interactions on a biochemical level.

  11. Analysis of genetic diversity and estimation of inbreeding coefficient ...

    African Journals Online (AJOL)

    STORAGESEVER

    2010-01-18

    Jan 18, 2010 ... The first method consisted in the application of three excess hete- rozygosity tests developed by Cornuet and Luikart (1996). The probability distribution was calculated using 1000 simulations under three models of evolution: infinite allele model (IAM), stepwise mutation model (SMM) and two phase model ...

  12. Demographic costs of inbreeding revealed by sex-specific genetic rescue effects

    Directory of Open Access Journals (Sweden)

    Zajitschek Felix

    2009-12-01

    Full Text Available Abstract Background Inbreeding can slow population growth and elevate extinction risk. A small number of unrelated immigrants to an inbred population can substantially reduce inbreeding and improve fitness, but little attention has been paid to the sex-specific effects of immigrants on such "genetic rescue". We conducted two subsequent experiments to investigate demographic consequences of inbreeding and genetic rescue in guppies. Results Populations established from pairs of full siblings that were descended either from two generations of full-sibling inbreeding or unrelated outbred guppies did not grow at different rates initially, but when the first generation offspring started breeding, outbred-founded populations grew more slowly than inbred-founded populations. In a second experiment, adding two outbred males to the inbred populations resulted in significantly faster population growth than in control populations where no immigrants were added. Adding females resulted in growth at a rate intermediate to the control and male-immigrant treatments. Conclusion The slower growth of the outbred-founded than inbred-founded populations is the opposite of what would be expected under inbreeding depression unless many deleterious recessive alleles had already been selectively purged in the inbreeding that preceded the start of the experiment, and that significant inbreeding depression occurred when the first generation offspring in outbred-founded populations started to inbreed. The second experiment revealed strong inbreeding depression in the inbred founded populations, despite the apparent lack thereof in these populations earlier on. Moreover, the fact that the addition of male immigrants resulted in the highest levels of population growth suggests that sex-specific genetic rescue may occur in promiscuous species, with male rescue resulting in higher levels of outbreeding than female rescue.

  13. Inbreeding effects on standard metabolic rate investigated at cold, benign and hot temperatures in Drosophila melanogaster.

    Science.gov (United States)

    Jensen, Palle; Overgaard, Johannes; Loeschcke, Volker; Schou, Mads Fristrup; Malte, Hans; Kristensen, Torsten Nygaard

    2014-03-01

    Inbreeding increases homozygosity, which is known to affect the mean and variance of fitness components such as growth, fecundity and mortality rate. Across inbred lines inbreeding depression is typically observed and the variance between lines is increased in inbred compared to outbred lines. It has been suggested that damage incurred from increased homozygosity entails energetic cost associated with cellular repair. However, little is known about the effects of inbreeding on standard metabolic rate. Using stop-flow respirometry we performed repeated measurements of metabolic rate in replicated lines of inbred and outbred Drosophila melanogaster at stressful low, benign and stressful high temperatures. The lowest measurements of metabolic rate in our study are always associated with the low activity period of the diurnal cycle and these measurements therefore serve as good estimates of standard metabolic rate. Due to the potentially added costs of genetic stress in inbred lines we hypothesized that inbred individuals have increased metabolic rate compared to outbred controls and that this is more pronounced at stressful temperatures due to synergistic inbreeding by environment interactions. Contrary to our hypothesis we found no significant difference in metabolic rate between inbred and outbred lines and no interaction between inbreeding and temperature. Inbreeding however effected the variance; the variance in metabolic rate was higher between the inbred lines compared to the outbred control lines with some inbred lines having very high or low standard metabolic rate. Thus genetic drift and not inbreeding per se seem to explain variation in metabolic rate in populations of different size. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Short Communication Inbreeding in the Dohne Merino breed in ...

    African Journals Online (AJOL)

    No significant inbreeding depression on body weight and fleece traits could be found. In general the results suggest that inbreeding at present is not a serious problem in the South African Dohne Merino breed. Keywords: Dohne Merino sheep; inbreeding depression. South African Journal of Animal Science Vol.

  15. Countering inbreeding with migration 1. Migration from unrelated ...

    African Journals Online (AJOL)

    The eff'ect of migration on inbreeding is moclelled fbr small populations with immigrants from a large unrelated population. Different migration rates and numbers fbr the two sexes are assumed, and a general recursion equation for inbreeding progress derived, which can be shown to lead to an equilibrium inbreeding ...

  16. Inbreeding in stochastic subdivided mating systems: the genetic ...

    Indian Academy of Sciences (India)

    2016-08-26

    Aug 26, 2016 ... My results indicate that levels of inbreeding in parasites are impacted by demographic and/or transmission dynamics (subdivided mating, aggregated transmission dynamics and host spatial structure), and that this inbreeding is poorly estimated by 'equilibrium' levels of inbreeding calculated assuming ...

  17. Inbreeding depression in selfs of redwood

    Science.gov (United States)

    W. J. Libby; B. G. McCutchan; C. I. Millar

    1981-01-01

    Given the polyploid chromosome constitution of Sequoia sempervirens, there was reason to question whether it would exhibit inbreeding depression. Preliminary results from studies of self and related outcross families are reported as a guide to the selection of trees for redwood seed orchards and breeding-orchards. The data indicate that, compared to...

  18. Inbreeding in genome-wide selection

    NARCIS (Netherlands)

    Daetwyler, H.D.; Villanueva, B.; Bijma, P.; Woolliams, J.A.

    2007-01-01

    Traditional selection methods, such as sib and best linear unbiased prediction (BLUP) selection, which increased genetic gain by increasing accuracy of evaluation have also led to an increased rate of inbreeding per generation (¿FG). This is not necessarily the case with genome-wide selection, which

  19. Inbreeding effects on standard metabolic rate investigated at cold, benign and hot temperatures in Drosophila melanogaster

    DEFF Research Database (Denmark)

    Jensen, Palle; Overgaard, Johannes; Loeschcke, Volker

    2014-01-01

    in replicated lines of inbred and outbred Drosophila melanogaster at stressful low, benign and stressful high temperatures. The lowest measurements of metabolic rate in our study are always associated with the low activity period of the diurnal cycle and these measurements therefore serve as good estimates...... of standard metabolic rate. Due to the potentially added costs of genetic stress in inbred lines we hypothesized that inbred individuals have increased metabolic rate compared to outbred controls and that this is more pronounced at stressful temperatures due to synergistic inbreeding by environment...... interactions. Contrary to our hypothesis we found no significant difference in metabolic rate between inbred and outbred lines and no interaction between inbreeding and temperature. Inbreeding however effected the variance; the variance in metabolic rate was higher between the inbred lines compared...

  20. Towards a complete North American Anabaptist Genealogy II: analysis of inbreeding.

    Science.gov (United States)

    Agarwala, R; Schäffer, A A; Tomlin, J F

    2001-08-01

    We describe a large genealogy data base, which can be searched by computer, of 295,095 Amish and Mennonite individuals. The data base was constructed by merging our existing Anabaptist Genealogy Database 2.0 containing approximately 85,000 individuals with a genealogy file containing approximately 242,000 individuals, kindly provided by Mr. James Hostetler. The merging process corrected thousands of inconsistencies and eliminated hundreds of duplicate individuals. Geneticists have long been interested in Anabaptist populations because they are closed and have detailed written genealogies. The creation of an enlarged and unified data base affords the opportunity to examine inbreeding trends and correlates in these populations. We show the following results. The frequency of consanguineous marriages shows steady increase over time and reached approximately 85% for individuals born in 1940-1959. Among consanguineous marriages, the median kinship coefficient stayed stable in the 19th century, but rose from 0.0115 to 0.0151 in the 20th century. There are statistically significant associations (p < 0.0001) between inbreeding and family size and interbirth intervals in the 20th century. There is an association (p < 0.0005) between inbreeding and early death for individuals born in 1920-1959. However, this association reverses dramatically (p < 0.0005 in the opposite direction) for individuals born in 1960-1979. We tested for an association between inbreeding and being the mother of twins, but found none.

  1. Hatching asynchrony aggravates inbreeding depression in a songbird (Serinus canaria): an inbreeding-environment interaction.

    Science.gov (United States)

    de Boer, Raïssa A; Eens, Marcel; Fransen, Erik; Müller, Wendt

    2015-04-01

    Understanding how the intensity of inbreeding depression is influenced by stressful environmental conditions is an important area of enquiry in various fields of biology. In birds, environmental stress during early development is often related to hatching asynchrony; differences in age, and thus size, impose a gradient in conditions ranging from benign (first hatched chick) to harsh (last hatched chick). Here, we compared the effect of hatching order on growth rate in inbred (parents are full siblings) and outbred (parents are unrelated) canary chicks (Serinus canaria). We found that inbreeding depression was more severe under more stressful conditions, being most evident in later hatched chicks. Thus, consideration of inbreeding-environment interactions is of vital importance for our understanding of the biological significance of inbreeding depression and hatching asynchrony. The latter is particularly relevant given that hatching asynchrony is a widespread phenomenon, occurring in many bird species. The exact causes of the observed inbreeding-environment interaction are as yet unknown, but may be related to a decrease in maternal investment in egg contents with laying position (i.e. prehatching environment), or to performance of the chicks during sibling competition and/or their resilience to food shortage (i.e. posthatching environment). © 2015 The Author(s).

  2. EFFECT OF INBREEDING ON MORPHOLOGICAL TRAITS OF POPULATIONS OF GIANT FRESH WATER PRAWN, Macrobrachium rosenbergii: IMPLICATIONS FOR SELECTIVE BREEDING

    Directory of Open Access Journals (Sweden)

    Imron Imron

    2013-12-01

    Full Text Available Genetic improvement through selective breeding relies on the genetically-controlled phenotypic variability in the character of interest. Therefore, the extent of phenotypic variability in the population to be selected is an important parameter, as it potentially influences the population’s response to selection. This study was aimed to investigate the effect of inbreeding on the survivability, growth, and phenotypic variability of giant freshwater prawn (GFP, Macrobrachium rosenbergii. Two GFP populations of different inbreeding levels, namely 25% and 0%, respectively, were formed by mating of individual broodstock with known pedigree. Study was conducted for two months starting from newly hatched larvae up to nursery stage (30 day-old post larva. Phenotypic variability profile, expressed in the morphometric mean and coefficient of variation (CV of twenty one morphometric characters were measured and evaluated. Results showed that in general, the inbred populations had lower values in the mean of all characters (100%, indicating that they suffered from inbreeding depression. Similarly, a lower CV values were observed in sixteen (75% of the morphometric characters measured, indicating a potential reduced of genetic gain when they are used in selective breeding program. These results suggest the importance of controlling inbreeding level in breeding population that adverse effects resulted resulted from inbreeding can be minimized.

  3. Inbreeding and its effect on some productive traits in buffaloes of South Iran

    Directory of Open Access Journals (Sweden)

    B. Mahmoodi

    2010-02-01

    Full Text Available The buffalo is a native animal of Iran and there were 500,000 buffaloes in Iran that over 80 per cent of its population concentrated in the north and north- west (Azerbaijan province and 18 per cent in the south (Khuzestan province of the country. Buffaloes reread in rural condition as multi purpose animals in Khuzestan. For mating, farmer use owns herd sire also artificial insemination is limited in the rural condition that may be inbred animals so affect the production performance. The aim of this investigation was estimate the inbreeding coefficient and its affect on some production performance. Data of 200 herds were used from the record sheets of herds under recording program of Animal Breeding Center during period 1990 to 2002 in the Khuzestan province. These results showed mostly herds only one sir and rarely two sires have been used. Inbreeding coefficient was 25 percent in some progeny and high-inbred buffaloes had a low performance. According to results of this study it could be concluded that farmers to avoid inbreeding should use other herd sire and artificial insemination also practical recording scheme and genetically selection to genetic improvement should be included in buffaloes of Iran.

  4. [Genetic isolates and inbreeding customs in three rural municipalities from Honduras].

    Science.gov (United States)

    Herrera-Paz, Edwin Francisco

    2016-01-01

    The isonymic method has been amply used to assess the approximate genetic structure of human communities. The objective of the study was to evaluate the magnitude of genetic isolation and inbreeding customs in 57 communities from three rural municipalities of Honduras using isonymy techniques. The list of 408 different surnames from 20712 voters registered in the national electoral organism, residing in the 57 Honduran communities, was used for this study. For each community, random (IR), non-random (IN), and total (IT) isonymy values were calculated in order to assess inbreeding coefficients FST, FIS and FIT. High consanguinity due to isolation and to endogamous customs was unveiled in many communities. Significant deviation from the exogamous behavior typical of many human populations was observed in the three studied municipalities, when compared to other Honduran populations. The studied communities present high consanguinity due to isolation, ethnic segregation and/or endogamous customs.

  5. Inbreeding depression in urban environments of the bird's nest fungus Cyathus stercoreus (Nidulariaceae: Basidiomycota).

    Science.gov (United States)

    Malloure, B D; James, T Y

    2013-04-01

    Many organisms display codispersal of offspring, but fewer display codispersal of compatible gametes. This mechanism enhances the ability of a species to colonize after long distance dispersal as a mechanism of reproductive assurance, but it also fosters inbreeding and potential reduction in fitness. Here we investigated both long distance dispersal and inbreeding in the bird's nest fungus Cyathus stercoreus, a dung and mulch-associated fungus with a splash cup fruiting body appearing like a miniature bird's nest of 'eggs' or peridioles that contain thousands of mating compatible meiotic spores. To investigate the genetic structure in the species, six North American urban populations were hierarchically sampled and genotyped using 10 microsatellite markers. We detected significant levels of inbreeding through heterozygote deficiencies at four loci, with global FIS=0.061. Dispersal limitation was suggested by both spatial autocorrelation and the detection of population structure between Louisiana and Michigan using clustering and F-statistics. Although inbreeding may facilitate colonization by the fungus, it has a negative effect on the fitness of populations as estimated from a 15% reduction in growth rates of inbred strains relative to outcrossed. Mating tests revealed that C. stercoreus has a higher estimated number of mating-type alleles (MAT-A= 39, MAT-B= 24) than other species of bird's nest fungi, which would increase its outcrossing efficiency. We speculate that the increased number of mating-type alleles is the result of a recent range and population size expansion into urban environments.

  6. Inbreeding and oubreeding effects on pollen fitness and zygote survival in Silene nutans (Caryophyllaceae)

    DEFF Research Database (Denmark)

    Hauser, Thure Pavlo; Siegismund, H.R.

    2000-01-01

    inbreeding depression, oubreeding effects, outcrossing, pollen fitness, selfing, Silene nutans, zygote survival......inbreeding depression, oubreeding effects, outcrossing, pollen fitness, selfing, Silene nutans, zygote survival...

  7. Short communication: Analysis of inbreeding of the South African ...

    African Journals Online (AJOL)

    In South Africa, the Dairy Swiss breed, which originated in Switzerland, consists of 27 breeders and 1135 breeding cows. Pedigree information on the breed was analysed to determine its effective population size (Ne) and rate of inbreeding. The rate of inbreeding was 0.08% per year and 0.38% per generation.

  8. Short communication Analysis of inbreeding of the South African ...

    African Journals Online (AJOL)

    2013-03-09

    Mar 9, 2013 ... Abstract. In South Africa, the Dairy Swiss breed, which originated in Switzerland, consists of 27 breeders and. 1135 breeding cows. Pedigree information on the breed was analysed to determine its effective population size (Ne) and rate of inbreeding. The rate of inbreeding was 0.08% per year and 0.38% ...

  9. Revealing gene action for production characteristics by inbreeding ...

    African Journals Online (AJOL)

    Revealing gene action for production characteristics by inbreeding, based on a long-term selection ... The gene action involved in the expression of production characters was investigated, using the effect of the theoretical inbreeding ..... and predicted selection responses for growth, fat and lean traits in mice. J. Anim. Sci.

  10. Inbreeding in the Elsenburg Dormer sheep stud | van Wyk | South ...

    African Journals Online (AJOL)

    Data of the Elsenburg Dormer sheep stud which was kept closed since its inception, were collected over a period of 50 years (1941-1990). These data were analysed to monitor the increase in actual level of inbreeding and to investigate the effect of inbreeding on some early growth and reproduction traits. In total, 9 551 ...

  11. Inbreeding and sex: canalization, plasticity and sexual selection

    Indian Academy of Sciences (India)

    Unknown

    interaction of environment and inbreeding depression. (Bijlsma et al. 1999; Dahlgaard and Hoffmann 2000), and the effect of inbreeding on genetic and phenotypic variance (Lopez-Fanjul and Villaverde 1989; Fowler and. Whitlock 1999), have been under renewed examination. Parallel to this has been a renewed interest ...

  12. Assessment of inbreeding depression for functional herd life in the ...

    African Journals Online (AJOL)

    The objective of this study was to investigate the effect of inbreeding depression on functional herd life in the South African Jersey population based on individual level and rate of inbreeding. A pedigree file of the South African Jersey breed (n = 912 638) was obtained from the Integrated Registration and Genetic ...

  13. Microsatellite-based estimation of inbreeding level in sheep ...

    African Journals Online (AJOL)

    In sheep populations with small effective population sizes (Ne), inbreeding is a major concern because genetic variation has to be maintained. A panel of 28 microsatellite markers was used to measure the inbreeding level in three separate Merino flocks bred for superfine wool (CR), low parasite resistance (LR) or high ...

  14. Inbreeding and the evolution of sociality in arthropods.

    Science.gov (United States)

    Tabadkani, Seyed Mohammad; Nozari, Jamasb; Lihoreau, Mathieu

    2012-10-01

    Animals have evolved strategies to optimally balance costs and benefits of inbreeding. In social species, these adaptations can have a considerable impact on the structure, the organization, and the functioning of groups. Here, we consider how selection for inbreeding avoidance fashions the social behavior of arthropods, a phylum exhibiting an unparalleled richness of social lifestyles. We first examine life histories and parental investment patterns determining whether individuals should actively avoid or prefer inbreeding. Next, we illustrate the diversity of inbreeding avoidance mechanisms in arthropods, from the dispersal of individuals to the rejection of kin during mate choice and the production of unisexual broods by females. Then, we address the particular case of haplodiploid insects. Finally, we discuss how inbreeding may drive and shape the evolution of arthropods societies along two theoretical pathways.

  15. Estimating relatedness and inbreeding using molecular markers and pedigrees: the effect of demographic history.

    Science.gov (United States)

    Robinson, S P; Simmons, L W; Kennington, W J

    2013-12-01

    Estimates of inbreeding and relatedness are commonly calculated using molecular markers, although the accuracy of such estimates has been questioned. As a further complication, in many situations, such estimates are required in populations with reduced genetic diversity, which is likely to affect their accuracy. We investigated the correlation between microsatellite- and pedigree-based coefficients of inbreeding and relatedness in laboratory populations of Drosophila melanogaster that had passed through bottlenecks to manipulate their genetic diversity. We also used simulations to predict expected correlations between marker- and pedigree-based estimates and to investigate the influence of linkage between loci and null alleles. Our empirical data showed lower correlations between marker- and pedigree-based estimates in our control (nonbottleneck) population than were predicted by our simulations or those found in similar studies. Correlations were weaker in bottleneck populations, confirming that extreme reductions in diversity can compromise the ability of molecular estimates to detect recent inbreeding events. However, this result was highly dependent on the strength of the bottleneck and we did not observe or predict any reduction in correlations in our population that went through a relatively severe bottleneck of N = 10 for one generation. Our results are therefore encouraging, as molecular estimates appeared robust to quite severe reductions in genetic diversity. It should also be remembered that pedigree-based estimates may not capture realized identity-by-decent and that marker-based estimates may actually be more useful in certain situations. © 2013 John Wiley & Sons Ltd.

  16. Higher values of spectral response, absorption coefficient and external quantum efficiency of solar cell in the form of pyramids

    Science.gov (United States)

    Hamel, A.

    2017-05-01

    This paper presents a study on spectral response, absorption coefficient and external quantum efficiency of solar cell in the form of pyramid [1, 2]. We investigate to what extent and under what conditions we want to take advantage of ray incidence Seven times [3, 4]. It is found that these analyses can be used to determine the optimal surface texture which provides the best light trapping for solar cells in terms of the total internal reflection occurring in the high-index medium at incidence angles larger than the nominal critical angle [3-9]. One of the main contributions of this paper is the analysis and quantification of the influence of the opening between the heads of the two closest pyramids in textured surface for solar cells and its application on the photovoltaic parameters. In this model we show that the material can have seven successive incident ray absorptions instead of five currently, where we changed the direction of the reflected ray, by identifying and install the angle between the two neighbouring pyramids, the incidence angle, the opening between the heads of the two closest pyramids and their height. Thus, with an angle between the two neighbouring pyramid fixed at 12° and for angle of incidence fixed at 84°. For these values of the angle between the two neighbouring pyramids and incidence angle, the opening between the heads of the two closest pyramids fixed at 2.10 μm for a pyramid height of 10 μm. This leads to the largest possible increase in optical efficiency, such as spectral response, Absorption Coefficient and External Quantum Efficiency. The results are in good agreement with the available literature.

  17. Evidence of inbreeding depression on human height.

    Directory of Open Access Journals (Sweden)

    Ruth McQuillan

    Full Text Available Stature is a classical and highly heritable complex trait, with 80%-90% of variation explained by genetic factors. In recent years, genome-wide association studies (GWAS have successfully identified many common additive variants influencing human height; however, little attention has been given to the potential role of recessive genetic effects. Here, we investigated genome-wide recessive effects by an analysis of inbreeding depression on adult height in over 35,000 people from 21 different population samples. We found a highly significant inverse association between height and genome-wide homozygosity, equivalent to a height reduction of up to 3 cm in the offspring of first cousins compared with the offspring of unrelated individuals, an effect which remained after controlling for the effects of socio-economic status, an important confounder (χ(2 = 83.89, df = 1; p = 5.2 × 10(-20. There was, however, a high degree of heterogeneity among populations: whereas the direction of the effect was consistent across most population samples, the effect size differed significantly among populations. It is likely that this reflects true biological heterogeneity: whether or not an effect can be observed will depend on both the variance in homozygosity in the population and the chance inheritance of individual recessive genotypes. These results predict that multiple, rare, recessive variants influence human height. Although this exploratory work focuses on height alone, the methodology developed is generally applicable to heritable quantitative traits (QT, paving the way for an investigation into inbreeding effects, and therefore genetic architecture, on a range of QT of biomedical importance.

  18. On General boundary value problem for an elliptic higher order equation in the plane with constant real coefficients

    Science.gov (United States)

    Bogan, Yu A.

    2017-10-01

    By means of a new approach, the general boundary value problem for a higher order elliptic equation with two independent variables, and a normal set of boundary conditions and simple complex characteristics is reduced to the Fredholm system of integral equations in a bounded region with a smooth boundary.

  19. Inbreeding depression of mating behavior and its reproductive consequences in a freshwater snail

    OpenAIRE

    Janicke Tim; Vellnow Nikolas; Lamy Thomas; Chapuis Elodie; David Patrice

    2014-01-01

    Inbreeding is expected to impair male and female reproductive performance, but little is known on how inbreeding depression varies between sexes and different levels of competition. We studied inbreeding depression in mating behavior and its reproductive consequences in a hermaphroditic freshwater snail and demonstrate that inbreeding depresses mating success in both sex functions. However, the magnitude of inbreeding depression does not differ between sex functions and is not affected by the...

  20. Predicting rates of inbreeding in populations undergoing selection

    NARCIS (Netherlands)

    Woolliams, J.A.; Bijma, P.

    2000-01-01

    Tractable forms of predicting rates of inbreeding (F) in selected populations with general indices, nonrandom mating, and overlapping generations were developed, with the principal results assuming a period of equilibrium in the selection process. An existing theorem concerning the relationship

  1. Interactions of inbreeding and stress by poor host quality in a root hemiparasite.

    Science.gov (United States)

    Sandner, Tobias Michael; Matthies, Diethart

    2017-01-01

    Populations of many hemiparasitic plants are fragmented and threatened by inbreeding depression (ID). In addition, they may also be strongly affected by a lack of suitable host species. However, nothing is known about possible interactive effects of inbreeding and host quality for parasitic plants. Poor host quality represents a special type of biotic stress and the magnitude of ID is often expected to be higher in more stressful environments. We studied the effects of inbreeding and the quality of host species for the declining root hemiparasite Rhinanthus alectorolophus Selfed and open-pollinated parasites from two natural populations were grown (1) with 13 potential host species and (2) with 15 four-species mixtures. ID differed among host species and mixtures. In the first experiment, ID was highest in parasites grown with good hosts and declined with stress intensity. In the second experiment, ID was not influenced by stress intensity, but was highest in mixtures of hosts from only one functional group and lowest in mixtures containing three functional groups. Both parasite performance with individual host species and the damage to these host species differed between parasites from the two study populations. Our results contradict the common assumption that ID is generally higher in more stressful environments. In addition, they support the importance of diverse host communities for hemiparasitic plants. The differences in host quality between the two parasite populations indicate genetic variation in the adaptation to individual hosts and in host-specific virulence. However, inbreeding did not affect specific host-parasite interactions. © The Author 2016. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  2. Demographic consequences of inbreeding and outbreeding in Arnica montana: A field experiment

    Science.gov (United States)

    Luijten, S.H.; Kery, M.; Oostermeijer, J.G.B.; Den, Nijs H.J.C.M.

    2002-01-01

    1. The genetic constitution of populations may significantly affect demography. Founder populations or isolated remnants may show inbreeding depression, while established populations can be strongly adapted to the local environment. Gene exchange between populations can lead to better performance if heterozygosity levels are restored (heterosis), or to reduced performance if coadapted gene complexes are disrupted (outbreeding depression). 2. Five populations of the self-incompatible perennial Arnica montana (Asteraceae) were analysed for the demographic consequences of inbreeding and of intra- and interpopulation outcrossing, using both small and large populations as donors for the latter. We analysed seed production and seed weight and monitored growth, survival and flowering of offspring introduced as seeds and as 4-week-old seedlings in a 4-year field experiment. 3. Reduced seed set after selfing was probably due to the self-incompatibility system rather than to inbreeding depression. There was a significant increase for seed set after interpopulation crosses, which resulted from the alleviation of low mate availability in one of the small populations. 4. Significant inbreeding depression was observed for growth rates of plants introduced as seedlings. We found significant heterosis for flowering probability of plants introduced as seeds, but for plants introduced as seedlings, heterosis for seedling size and flowering probability was only marginally significant. Outbreeding depression was not observed. 5. The results of this study are important for reinforcement measures in small, remnant populations. Significant differences among populations for all measured fitness components suggest that reinforcement is best achieved using material from several populations. 6. The observed higher survival of seedlings as compared with seeds suggests that it is better to plant individuals than to sow. Sowing, however, is easier and cheaper, and was more likely to eliminate

  3. Cost of inbreeding in resistance to herbivores in Datura stramonium.

    Science.gov (United States)

    Bello-Bedoy, Rafael; Núñez-Farfán, Juan

    2010-05-01

    Experiments show that inbred progenies are frequently more damaged by herbivores than outcrossed progenies, suggesting that selfing is costly when herbivores are present and can increase the magnitude of inbreeding depression in survival and reproductive components of fitness. The present study assesses whether inbreeding increases herbivory and estimates the magnitude of inbreeding depression on reproductive components of fitness in the annual plant Datura stramonium. Two experiments were performed under natural conditions of herbivory to assess the effect of inbreeding on plant damage in D. stramonium. In the first experiment, outcrossed progeny was generated using foreign pollen donors, whereas inbred progeny was produced by self-pollination. In both groups, survival, herbivore damage and reproductive components of fitness were measured. In the second experiment, inbred and outcrossed progenies were produced using only local pollen donors, and only damage by herbivores was measured. Despite yearly variation in damage caused by the same specialist herbivores, inbred progeny suffered consistently more damage than outcrossed progeny. There was a significant inbreeding depression for fruit number (delta = 0.3), seed number per fruit (delta = 0.19) and seed number per plant (delta = 0.43). Furthermore, significant genetic variation amongst families in the magnitude of inbreeding depression was observed. The results suggest that the plant's mating system modified the pattern of herbivory by specialist insects in D. stramonium. Inbred plants suffer not only from the genetic cost of low vigour but also from greater damage by herbivores. The mechanism by which inbreeding reduces plant resistance to herbivores remains unknown but is an interesting area for future research.

  4. Breather transition dynamics, Peregrine combs and walls, and modulation instability in a variable-coefficient nonlinear Schrödinger equation with higher-order effects

    Science.gov (United States)

    Wang, Lei; Zhang, Jian-Hui; Liu, Chong; Li, Min; Qi, Feng-Hua

    2016-06-01

    We study a variable-coefficient nonlinear Schrödinger (vc-NLS) equation with higher-order effects. We show that the breather solution can be converted into four types of nonlinear waves on constant backgrounds including the multipeak solitons, antidark soliton, periodic wave, and W -shaped soliton. In particular, the transition condition requiring the group velocity dispersion (GVD) and third-order dispersion (TOD) to scale linearly is obtained analytically. We display several kinds of elastic interactions between the transformed nonlinear waves. We discuss the dispersion management of the multipeak soliton, which indicates that the GVD coefficient controls the number of peaks of the wave while the TOD coefficient has compression effect. The gain or loss has influence on the amplitudes of the multipeak soliton. We further derive the breather multiple births and Peregrine combs by using multiple compression points of Akhmediev breathers and Peregrine rogue waves in optical fiber systems with periodic GVD modulation. In particular, we demonstrate that the Peregrine comb can be converted into a Peregrine wall by the proper choice of the amplitude of the periodic GVD modulation. The Peregrine wall can be seen as an intermediate state between rogue waves and W -shaped solitons. We finally find that the modulational stability regions with zero growth rate coincide with the transition condition using rogue wave eigenvalues. Our results could be useful for the experimental control and manipulation of the formation of generalized Peregrine rogue waves in diverse physical systems modeled by vc-NLS equation with higher-order effects.

  5. Mixed higher-order flow harmonics and nonlinear response coefficients in PbPb collisions at 2.76 and 5.02 TeV with CMS

    CERN Document Server

    Tuo, Shengquan

    2017-01-01

    The mixed higher-order flow harmonics and nonlinear response coefficients of charged particles are presented as a function of $p_{\\rm{T}}$ and centrality in PbPb collisions at $\\sqrt{s_{NN}}$ = 2.76 TeV and 5.02 TeV with the CMS detector. The results are obtained using the scalar product method, and cover a $p_{\\rm{T}}$ range from 0.3 GeV/c to 8.0 GeV/c, pseudorapidity $\\vert\\eta\\vert <$ 2.4, and a centrality range of 0-60$\\%$. The mixed harmonic results at 5.02 TeV are compared to the matching higher-order flow harmonics from two-particle correlations, which measure $v_n$ values with respect to the $n$-th order event plane. It is observed that the nonlinear response coefficients of the odd harmonics are larger than the even harmonics ones. The results are compared with hydrodynamic predictions using different shear viscosity to entropy density ratios and different initial conditions.

  6. ARTICLE - Inbreeding depression in castor bean (Ricinus communis L. progenies

    Directory of Open Access Journals (Sweden)

    Milton Krieger

    2012-12-01

    Full Text Available The purpose of this study was to investigate inbreeding depression (DE in castor bean. From a population derived from the Guarani cultivar, 60 mother plants were sampled. Three types of progenies were obtained from each one: from self-pollination (AU, from crosses (CR and from open pollination (PL. Grain yield of the progenies was evaluated in two locations. There was a strong interaction of progenies x locations, which led to obtaining estimates within each location. Broad variation was observed in inbreeding depression, with mean values of 6.7% and 13.4%, comparing AU progenies with PL progenies. It was observed that the population has high potential for selecting promising inbred lines. The frequency of mother plants generating progenies with simultaneous high general combination capacity and low inbreeding depression was low. Recurrent selection will increase the occurrence of parent plants associating these two properties, which is necessary for obtaining superior synthetic varieties.

  7. Proteomic characterization of inbreeding-related cold sensitivity in Drosophila melanogaster

    DEFF Research Database (Denmark)

    Vermeulen, Cornelis Joseph; Pedersen, Kamilla Sofie; Beck, Hans C

    2013-01-01

    insight into the molecular interplay between intrinsic stress responses, inbreeding depression and temperature tolerance, we performed a proteomic characterization of a well-defined conditional inbreeding effect in a single line of Drosophila melanogaster, which suffers from extreme cold sensitivity...

  8. Inbreeding in Mimulus guttatus reduces visitation by bumble bee pollinators.

    Directory of Open Access Journals (Sweden)

    David E Carr

    Full Text Available Inbreeding in plants typically reduces individual fitness but may also alter ecological interactions. This study examined the effect of inbreeding in the mixed-mating annual Mimulus guttatus on visitation by pollinators (Bombus impatiens in greenhouse experiments. Previous studies of M. guttatus have shown that inbreeding reduced corolla size, flower number, and pollen quantity and quality. Using controlled crosses, we produced inbred and outbred families from three different M. guttatus populations. We recorded the plant genotypes that bees visited and the number of flowers probed per visit. In our first experiment, bees were 31% more likely to visit outbred plants than those selfed for one generation and 43% more likely to visit outbred plants than those selfed for two generations. Inbreeding had only a small effect on the number of flowers probed once bees arrived at a genotype. These differences were explained partially by differences in mean floral display and mean flower size, but even when these variables were controlled statistically, the effect of inbreeding remained large and significant. In a second experiment we quantified pollen viability from inbred and self plants. Bees were 37-54% more likely to visit outbred plants, depending on the population, even when controlling for floral display size. Pollen viability proved to be as important as floral display in predicting pollinator visitation in one population, but the overall explanatory power of a multiple regression model was weak. Our data suggested that bees use cues in addition to display size, flower size, and pollen reward quality in their discrimination of inbred plants. Discrimination against inbred plants could have effects on plant fitness and thereby reinforce selection for outcrossing. Inbreeding in plant populations could also reduce resource quality for pollinators, potentially resulting in negative effects on pollinator populations.

  9. Plant traits correlated with generation time directly affect inbreeding depression and mating system and indirectly genetic structure

    Directory of Open Access Journals (Sweden)

    Hardy Olivier J

    2009-07-01

    Full Text Available Abstract Background Understanding the mechanisms that control species genetic structure has always been a major objective in evolutionary studies. The association between genetic structure and species attributes has received special attention. As species attributes are highly taxonomically constrained, phylogenetically controlled methods are necessary to infer causal relationships. In plants, a previous study controlling for phylogenetic signal has demonstrated that Wright's FST, a measure of genetic differentiation among populations, is best predicted by the mating system (outcrossing, mixed-mating or selfing and that plant traits such as perenniality and growth form have only an indirect influence on FST via their association with the mating system. The objective of this study is to further outline the determinants of plant genetic structure by distinguishing the effects of mating system on gene flow and on genetic drift. The association of biparental inbreeding and inbreeding depression with population genetic structure, mating system and plant traits are also investigated. Results Based on data from 263 plant species for which estimates of FST, inbreeding (FIS and outcrossing rate (tm are available, we confirm that mating system is the main influencing factor of FST. Moreover, using an alternative measure of FST unaffected by the impact of inbreeding on effective population size, we show that the influence of tm on FST is due to its impact on gene flow (reduced pollen flow under selfing and on genetic drift (higher drift under selfing due to inbreeding. Plant traits, in particular perenniality, influence FST mostly via their effect on the mating system but also via their association with the magnitude of selection against inbred individuals: the mean inbreeding depression increases from short-lived herbaceous to long-lived herbaceous and then to woody species. The influence of perenniality on mating system does not seem to be related to

  10. AN ACTION OF EXOGENOUS STEROIDAL GLYCOSIDE ON EXHIBITION OF INBREEDING DEPRESSION IN RED BEET PLANTS UNDER PROTECTED CULTIVATION TECHNOLOGY

    Directory of Open Access Journals (Sweden)

    E. G. Kozar

    2017-01-01

    plants. This caused the improved seed formation 1.6-2.2 times higher during inbreeding process and increased the portion of plants with high productivity. The SGC had no effect on exhibition of CMS trait. Thus, the SGC is worth using in valuable highly inbreeding forms inclined to self-sterility, in order to enlarge the genetic variation and output of divers generations. However, it should be taken into consideration that the complicated effect on the plant traits can be noticed in inbreeding generation of red beet and may have an effect on the result of selection process at the root stage.

  11. Soliton-like solutions of a generalized variable-coefficient higher order nonlinear Schroedinger equation from inhomogeneous optical fibers with symbolic computation

    International Nuclear Information System (INIS)

    Li Juan; Zhang Haiqiang; Xu Tao; Zhang, Ya-Xing; Tian Bo

    2007-01-01

    For the long-distance communication and manufacturing problems in optical fibers, the propagation of subpicosecond or femtosecond optical pulses can be governed by the variable-coefficient nonlinear Schroedinger equation with higher order effects, such as the third-order dispersion, self-steepening and self-frequency shift. In this paper, we firstly determine the general conditions for this equation to be integrable by employing the Painleve analysis. Based on the obtained 3 x 3 Lax pair, we construct the Darboux transformation for such a model under the corresponding constraints, and then derive the nth-iterated potential transformation formula by the iterative process of Darboux transformation. Through the one- and two-soliton-like solutions, we graphically discuss the features of femtosecond solitons in inhomogeneous optical fibers

  12. Variation in parent–offspring kinship in socially monogamous systems with extra‐pair reproduction and inbreeding

    Science.gov (United States)

    Reid, Jane M.; Bocedi, Greta; Nietlisbach, Pirmin; Duthie, A. Bradley; Wolak, Matthew E.; Gow, Elizabeth A.; Arcese, Peter

    2016-01-01

    Female extra‐pair reproduction in socially monogamous systems is predicted to cause cuckolded socially‐paired males to conditionally reduce paternal care, causing selection against extra‐pair reproduction and underlying polyandry. However, existing models and empirical studies have not explicitly considered that cuckolded males might be related to their socially‐paired female and/or to her extra‐pair mate, and therefore be related to extra‐pair offspring that they did not sire but could rear. Selection against paternal care, and hence against extra‐pair reproduction, might then be weakened. We derive metrics that quantify allele‐sharing between within‐pair and extra‐pair offspring and their mother and her socially‐paired male in terms of coefficients of kinship and inbreeding. We use song sparrow (Melospiza melodia) paternity and pedigree data to quantify these metrics, and thereby quantify the joint effects of extra‐pair reproduction and inbreeding on a brood's total allelic value to its socially‐paired parents. Cuckolded male song sparrows were almost always detectably related to extra‐pair offspring they reared. Consequently, although brood allelic value decreased substantially following female extra‐pair reproduction, this decrease was reduced by within‐pair and extra‐pair reproduction among relatives. Such complex variation in kinship within nuclear families should be incorporated into models considering coevolutionary dynamics of extra‐pair reproduction, parental care, and inbreeding. PMID:27174154

  13. Estimation of Heterosis and Inbreeding Depression in Quantitative ...

    African Journals Online (AJOL)

    It is important to know the degree and direction of heterosis for its commercial exploitation. Heterosis and in-breeding depression were estimated in 8x8 half diallel crosses of rice. The planted materials consisted ofeight parental inbred lines, their F1 hybrids and F2 populations using randomized complete block design with ...

  14. [Inbreeding, endogamy and exogamy among relatives of schizophrenia patients].

    Science.gov (United States)

    Abaskuliev, A A; Skoblo, G V

    1975-01-01

    An increased frequency of consanguineous marriages among the parents of schizophrenic patients in comparison with the control group of exogenous-somatic patients (infections, trauma) was found. Endogamy among the parents of schizophrenic patients and the control group was practically the same. The data obtained indicate a certain, but not the leading, role of inbreeding in the etiology of schizophrenia.

  15. Estimates of genetic parameters and effect of inbreeding on milk ...

    African Journals Online (AJOL)

    The statistical model included the fixed effects of herd-year-season, age of the cow at calving, calving interval, inbreeding as a discrete or continuous variable and random effects of direct additive genetic, permanent environment of the cow and the residual effects. The multitrait derivative-free REML algorithm was used to ...

  16. Breeding synchronization facilitates extrapair mating for inbreeding avoidance

    NARCIS (Netherlands)

    Kingma, Sjouke A.; Hall, Michelle L.; Peters, Anne

    2013-01-01

    Extrapair (EP) mating can enable females to reduce the negative effects of inbreeding. However, opportunities for EP mating are often ecologically or demographically constrained, and it is unclear whether and how females can overcome these constraints. Here, we show that fitness costs from

  17. Inbreeding depression of 28 maize elite open pollinated varieties

    Directory of Open Access Journals (Sweden)

    Cleso Antônio Patto Pacheco

    2002-01-01

    Full Text Available The study of inbreeding depression is important for breeding strategies such as use of inbred progenies or extraction of inbreed lines. A diallel of 28 maize open-pollinated varieties was evaluated in 10 environments in the early 1990s. At the same time, S1 populations for each of the 28 varieties were evaluated in the same 10 experiments (environments. Yield reductions of the populations from S0 to S1 (mean of the 10 environments, varied from 34.6% (CMS-01 to 59.2% (CMS-30, with an average of 49.1%. Inbreeding depression was greater in populations with a wider genetic base, which had never been exposed to inbreeding (CMS-30, BR-107, PH4, Cunha, Saracura, Nitrodent, and Nitroflint. Inbred lines with greater yield means should be obtained from the BR-105, BR-111, CMS-01, CMS-03, BR-106, CMS-14c, and CMS-28 populations. The use of parameter estimates generated by analysis of inbreeding depression, allow to make inferences about frequencies of deleterious alleles in the population. The frequencies of favorable alleles in the parents can be obtained by diallel analysis. The association of these two types of information, can provide a better interpretation of the genetic parameters and also can improve the process of selection of parents for either an intra- or an inter-populational breeding program.

  18. Short communication: Effective population size and inbreeding rate ...

    African Journals Online (AJOL)

    Short communication: Effective population size and inbreeding rate of indigenous Nguni cattle under in situ conservation in the low-input communal production ... as not at risk of extinction, while the individual enterprises were classified as being endangered-maintained without the exchange of germ plasm among them.

  19. Presence of inbreeding during a selection experiment with Merino ...

    African Journals Online (AJOL)

    Presence of inbreeding during a selection experiment with Merino sheep. GJ Erasmus, AO de Lange, GJ Delport, JJ Olivier. Abstract. No Abstract. Full Text: EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT · AJOL African Journals Online. HOW TO USE AJOL.

  20. Inbreeding affects locomotor activity in Drosophila melanogaster at different ages

    DEFF Research Database (Denmark)

    Manenti, Tommaso; Pertoldi, Cino; Nasiri Moghadam, Neda

    2015-01-01

    The ability to move is essential for many behavioural traits closely related to fitness. Here we studied the effect of inbreeding on locomotor activity (LA) of Drosophila melanogaster at different ages under both dark and light regimes. We expected to find a decreased LA in inbred lines compared...

  1. Inbreeding in the Danish populations of five Nordic sheep breeds

    DEFF Research Database (Denmark)

    Sørensen, Anders Christian; Norberg, Elise

    2008-01-01

    In Denmark there are small populations of five Nordic sheep breeds, two of which are Danish in origin. The purpose of this study was to estimate trends in inbreeding for these breeds. All five breeds have been recording pedigrees for decades, so pedigree completeness is adequate. The rate...

  2. Inbreeding and genetic diversity analysis in a hatchery release population and clones of Rhopilema esculentum based on microsatellite markers

    Science.gov (United States)

    Tian, Tao; Chen, Zaizhong; Wang, Mosang; Hu, Yulong; Wang, Weiji

    2017-05-01

    Ten microsatellite markers were used to analyze the levels of genetic diversity and inbreeding in a hatchery release population of Rhopilema esculentum Kishinouye (Scyphozoa: Rhizostomatidae). A total of 85 alleles were detected in 600 individuals. Within-population levels of observed ( H o) and expected ( H e) heterozygosity ranged from 0.152 to 0.839 (mean=0.464) and from 0.235 to 0.821 (mean=0.618), respectively. The polymorphism information content (PIC) of each marker ranged from 0.207 to 0.795 with an average of 0.580, indicating that the hatchery population maintained a high level of genetic diversity. Inbreeding levels were estimated in the hatchery population and the inbreeding coefficient was 0.203. This result revealed that a certain level of inbreeding occurred within the population. Meanwhile, we also determined genetic diversity at the clone level. Several polyps from the same scyphistomae were genotyped at the ten microsatellite loci and there was virtually no difference in their genotypes. Furthermore, we calculated the probabilities of exclusion. When both parents were known, the average exclusion probability of ten loci was 99.99%. Our data suggest that the ten microsatellite markers can not only be used to analyze the identity of individuals but they can also be applied to parentage identification. Our research provides a theoretical basis and technical support for genetic diversity detection and reasonable selection of R. esculentum hatchery populations. These findings support the use of releasing studies and conservation of R. esculentum germplasm resources.

  3. Demographic mechanisms of inbreeding adjustment through extra-pair reproduction.

    Science.gov (United States)

    Reid, Jane M; Duthie, A Bradley; Wolak, Matthew E; Arcese, Peter

    2015-07-01

    One hypothesis explaining extra-pair reproduction is that socially monogamous females mate with extra-pair males to adjust the coefficient of inbreeding (f) of extra-pair offspring (EPO) relative to that of within-pair offspring (WPO) they would produce with their socially paired male. Such adjustment of offspring f requires non-random extra-pair reproduction with respect to relatedness, which is in turn often assumed to require some mechanism of explicit pre-copulatory or post-copulatory kin discrimination. We propose three demographic processes that could potentially cause mean f to differ between individual females' EPO and WPO given random extra-pair reproduction with available males without necessarily requiring explicit kin discrimination. Specifically, such a difference could arise if social pairings formed non-randomly with respect to relatedness or persisted non-randomly with respect to relatedness, or if the distribution of relatedness between females and their sets of potential mates changed during the period through which social pairings persisted. We used comprehensive pedigree and pairing data from free-living song sparrows (Melospiza melodia) to quantify these three processes and hence investigate how individual females could adjust mean offspring f through instantaneously random extra-pair reproduction. Female song sparrows tended to form social pairings with unrelated or distantly related males slightly less frequently than expected given random pairing within the defined set of available males. Furthermore, social pairings between more closely related mates tended to be more likely to persist across years than social pairings between less closely related mates. However, these effects were small and the mean relatedness between females and their sets of potential extra-pair males did not change substantially across the years through which social pairings persisted. Our framework and analyses illustrate how demographic and social structuring within

  4. Evaluation of inbreeding depression in Holstein cattle using whole-genome SNP markers and alternative measures of genomic inbreeding.

    Science.gov (United States)

    Bjelland, D W; Weigel, K A; Vukasinovic, N; Nkrumah, J D

    2013-07-01

    The effects of increased pedigree inbreeding in dairy cattle populations have been well documented and result in a negative impact on profitability. Recent advances in genotyping technology have allowed researchers to move beyond pedigree analysis and study inbreeding at a molecular level. In this study, 5,853 animals were genotyped for 54,001 single nucleotide polymorphisms (SNP); 2,913 cows had phenotypic records including a single lactation for milk yield (from either lactation 1, 2, 3, or 4), reproductive performance, and linear type conformation. After removing SNP with poor call rates, low minor allele frequencies, and departure from Hardy-Weinberg equilibrium, 33,025 SNP remained for analyses. Three measures of genomic inbreeding were evaluated: percent homozygosity (FPH), inbreeding calculated from runs of homozygosity (FROH), and inbreeding derived from a genomic relationship matrix (FGRM). Average FPH was 60.5±1.1%, average FROH was 3.8±2.1%, and average FGRM was 20.8±2.3%, where animals with larger values for each of the genomic inbreeding indices were considered more inbred. Decreases in total milk yield to 205d postpartum of 53, 20, and 47kg per 1% increase in FPH, FROH, and FGRM, respectively, were observed. Increases in days open per 1% increase in FPH (1.76 d), FROH (1.72 d), and FGRM (1.06 d) were also noted, as well as increases in maternal calving difficulty (0.09, 0.03, and 0.04 on a 5-point scale for FPH, FROH, and FGRM, respectively). Several linear type traits, such as strength (-0.40, -0.11, and -0.19), rear legs rear view (-0.35, -0.16, and -0.14), front teat placement (0.35, 0.25, 0.18), and teat length (-0.24, -0.14, and -0.13) were also affected by increases in FPH, FROH, and FGRM, respectively. Overall, increases in each measure of genomic inbreeding in this study were associated with negative effects on production and reproductive ability in dairy cows. Copyright © 2013 American Dairy Science Association. Published by Elsevier Inc

  5. The impact of self-incompatibility systems on the prevention of biparental inbreeding

    Directory of Open Access Journals (Sweden)

    Tara N. Furstenau

    2017-11-01

    Full Text Available Inbreeding in hermaphroditic plants can occur through two different mechanisms: biparental inbreeding, when a plant mates with a related individual, or self-fertilization, when a plant mates with itself. To avoid inbreeding, many hermaphroditic plants have evolved self-incompatibility (SI systems which prevent or limit self-fertilization. One particular SI system—homomorphic SI—can also reduce biparental inbreeding. Homomorphic SI is found in many angiosperm species, and it is often assumed that the additional benefit of reduced biparental inbreeding may be a factor in the success of this SI system. To test this assumption, we developed a spatially-explicit, individual-based simulation of plant populations that displayed three different types of homomorphic SI. We measured the total level of inbreeding avoidance by comparing each population to a self-compatible population (NSI, and we measured biparental inbreeding avoidance by comparing to a population of self-incompatible plants that were free to mate with any other individual (PSI. Because biparental inbreeding is more common when offspring dispersal is limited, we examined the levels of biparental inbreeding over a range of dispersal distances. We also tested whether the introduction of inbreeding depression affected the level of biparental inbreeding avoidance. We found that there was a statistically significant decrease in autozygosity in each of the homomorphic SI populations compared to the PSI population and, as expected, this was more pronounced when seed and pollen dispersal was limited. However, levels of homozygosity and inbreeding depression were not reduced. At low dispersal, homomorphic SI populations also suffered reduced female fecundity and had smaller census population sizes. Overall, our simulations showed that the homomorphic SI systems had little impact on the amount of biparental inbreeding in the population especially when compared to the overall reduction in

  6. Trait-specific consequences of inbreeding on adaptive phenotypic plasticity

    DEFF Research Database (Denmark)

    Schou, Mads Fristrup; Kristensen, Torsten Nygaard; Loeschcke, Volker

    2015-01-01

    Environmental changes may stress organisms and stimulate an adaptive phenotypic response. Effects of inbreeding often interact with the environment and can decrease fitness of inbred individuals exposed to stress more so than that of outbred individuals. Such an interaction may stem from a reduced...... ability of inbred individuals to respond plastically to environmental stress; however, this hypothesis has rarely been tested. In this study, we mimicked the genetic constitution of natural inbred populations by rearing replicate Drosophila melanogaster populations for 25 generations at a reduced...... shape across temperatures in inbred compared to control populations. Given that the norms of reaction for the noninbred control populations are adaptive, we conclude that a reduced ability to induce an adaptive phenotypic response to temperature changes is not a general consequence of inbreeding...

  7. Combining abilities and inbreeding depression in commercial maize hybrids

    Directory of Open Access Journals (Sweden)

    Henrique José Camargo Senhorinho

    2015-12-01

    Full Text Available The objective of this study was to evaluate the combining ability and inbreeding depression of commercial maize hybrids for agricultural traits. Twenty-two commercial maize hybrids, 96 F1 crosses from a partial diallel scheme, 22 S1 populations and 4 controls were evaluated in a 12x12 simples square lattice experimental setup, totaling 144 treatments, in the municipality of Sabáudia (PR, Brazil, for harvests from 2011/2012 and 2012/2013. Three traits were evaluated: grain yield, plant height and ear height. The Griffing method (1956 was applied for the evaluation of the general combining ability (GCA and specific combining ability (SCA. The 30B39, 30K64 and 30B30 hybrids showed increased yield, 30F53 and P1630 showed reduced plant height and AG9040 and AG7010 showed reduced ear height. These hybrids can be recommended for the extraction of inbred lines and formation of composites followed by intrapopulation selection. The combinations 30B39 x AG8088, 30B39 x AG9045 and P1630 x AG8021 showed desirable SCA effects for grain yield, plant height and ear height and are recommended for use in reciprocal recurrent selection programs. High magnitudes of inbreeding depression were verified for yield and lower values for inbreeding depression for plant and ear heights. Thus, strategies are recommended for interpopulation breeding accompanied by inbred lines extraction.

  8. An inbreeding model of associative overdominance during a population bottleneck.

    Science.gov (United States)

    Bierne, N; Tsitrone, A; David, P

    2000-08-01

    Associative overdominance, the fitness difference between heterozygotes and homozygotes at a neutral locus, is classically described using two categories of models: linkage disequilibrium in small populations or identity disequilibrium in infinite, partially selfing populations. In both cases, only equilibrium situations have been considered. In the present study, associative overdominance is related to the distribution of individual inbreeding levels (i.e., genomic autozygosity). Our model integrates the effects of physical linkage and variation in inbreeding history among individual pedigrees. Hence, linkage and identity disequilibrium, traditionally presented as alternatives, are summarized within a single framework. This allows studying nonequilibrium situations in which both occur simultaneously. The model is applied to the case of an infinite population undergoing a sustained population bottleneck. The effects of bottleneck size, mating system, marker gene diversity, deleterious genomic mutation parameters, and physical linkage are evaluated. Bottlenecks transiently generate much larger associative overdominance than observed in equilibrium finite populations and represent a plausible explanation of empirical results obtained, for instance, in marine species. Moreover, the main origin of associative overdominance is random variation in individual inbreeding whereas physical linkage has little effect.

  9. The effect of inbreeding on defence against multiple enemies in Datura stramonium.

    Science.gov (United States)

    Bello-Bedoy, R; Núñez-Farfán, J

    2011-03-01

    The ability of plants to respond to natural enemies might depend on the availability of genetic variation for the optimal phenotypic expression of defence. Selfing can affect the distribution of genetic variability of plant fitness, resistance and tolerance to herbivores and pathogens. The hypothesis of inbreeding depression influencing plant defence predicts that inbreeding would reduce resistance and tolerance to damage by natural enemies relative to outcrossing. In a field experiment entailing experimentally produced inbred and outcrossed progenies, we assessed the effects of one generation of selfing on Datura stramonium resistance and tolerance to three types of natural enemies, herbivores, weevils and a virus. We also examined the effect of damage on relative growth rate (RGR), flower, fruit, and seed production in inbred and outcrossed plants. Inbreeding significantly reduced plant defence to natural enemies with an increase of 4% in herbivore damage and 8% in viral infection. These results indicate inbreeding depression in total resistance. Herbivory increased 10% inbreeding depression in seed number, but viral damage caused inbred and outcrossed plants to have similar seed production. Inbreeding and outcrossing effects on fitness components were highly variable among families, implying that different types or numbers of recessive deleterious alleles segregate following inbreeding in D. stramonium. Although inbreeding did not equally alter all the interactions, our findings indicate that inbreeding reduced plant defence to herbivores and pathogens in D. stramonium. © 2010 The Authors. Journal of Evolutionary Biology © 2010 European Society For Evolutionary Biology.

  10. Inbreeding avoidance in spiders: evidence for rescue effect in fecundity of female spiders with outbreeding opportunity

    DEFF Research Database (Denmark)

    Bilde, T.; Maklakov, A.A.; Schilling, Nadia

    2007-01-01

    decline in fecundity and hatching rates of eggs. This effect was mitigated by complete recovery in fecundity in the sib-nonsib treatment, whereas no rescue effect was detected in the hatching success of eggs. The rescue effect is best explained by post-mating discrimination against kin via differential...... male nonsibs; one male sib and one male nonsib. We assessed the effect of mating treatment on fecundity and hatching success of eggs after one and three generations of inbreeding. Inbreeding depression in F1 was not sufficient to detect inbreeding avoidance. In F3, inbreeding depression caused a major...

  11. Higher levels of multiple paternities increase seedling survival in the long-lived tree Eucalyptus gracilis.

    Directory of Open Access Journals (Sweden)

    Martin F Breed

    Full Text Available Studying associations between mating system parameters and fitness in natural populations of trees advances our understanding of how local environments affect seed quality, and thereby helps to predict when inbreeding or multiple paternities should impact on fitness. Indeed, for species that demonstrate inbreeding avoidance, multiple paternities (i.e. the number of male parents per half-sib family should still vary and regulate fitness more than inbreeding--named here as the 'constrained inbreeding hypothesis'. We test this hypothesis in Eucalyptus gracilis, a predominantly insect-pollinated tree. Fifty-eight open-pollinated progeny arrays were collected from trees in three populations. Progeny were planted in a reciprocal transplant trial. Fitness was measured by family establishment rates. We genotyped all trees and their progeny at eight microsatellite loci. Planting site had a strong effect on fitness, but seed provenance and seed provenance × planting site did not. Populations had comparable mating system parameters and were generally outcrossed, experienced low biparental inbreeding and high levels of multiple paternity. As predicted, seed families that had more multiple paternities also had higher fitness, and no fitness-inbreeding correlations were detected. Demonstrating that fitness was most affected by multiple paternities rather than inbreeding, we provide evidence supporting the constrained inbreeding hypothesis; i.e. that multiple paternity may impact on fitness over and above that of inbreeding, particularly for preferentially outcrossing trees at life stages beyond seed development.

  12. Environmental conditions affect the magnitude of inbreeding depression in survival of Darwin's finches.

    Science.gov (United States)

    Keller, Lukas F; Grant, Peter R; Grant, B Rosemary; Petren, Kenneth

    2002-06-01

    Understanding the fitness consequences of inbreeding (inbreeding depression) is of importance to evolutionary and conservation biology. There is ample evidence for inbreeding depression in captivity, and data from wild populations are accumulating. However, we still lack a good quantitative understanding of inbreeding depression and what influences its magnitude in natural populations. Specifically, the relationship between the magnitude of inbreeding depression and environmental severity is unclear. We quantified inbreeding depression in survival and reproduction in populations of cactus finches (Geospiza scandens) and medium ground finches (Geospiza fortis) living on Isla Daphne Major in the Galápagos Archipelago. Our analyses showed that inbreeding strongly reduced the recruitment probability (probability of breeding given that an adult is alive) in both species. Additionally, in G. scandens, first-year survival of an offspring with f = 0.25 was reduced by 21% and adults with f = 0.25 experienced a 45% reduction in their annual probability of survival. The magnitude of inbreeding depression in both adult and juvenile survival of this species was strongly modified by two environmental conditions, food availability and number of competitors. In juveniles, inbreeding depression was only present in years with low food availability, and in adults inbreeding depression was five times more severe in years with low food availability and large population sizes. The combination of relatively severe inbreeding depression in survival and the reduced recruitment probability led to the fact that very few inbred G. scandens ever succeeded in breeding. Other than recruitment probability, no other trait showed evidence of inbreeding depression in G. fortis, probably for two reasons: a relatively high rate of extrapair paternity (20%), which may lead to an underestimate of the apparent inbreeding depression, and low sample sizes of highly inbred G. fortis, which leads to low

  13. Trait specific consequences of fast and slow inbreeding: lessonsfrom captive populations of Drosophila melanogaster

    DEFF Research Database (Denmark)

    Mikkelsen, Karina Aarup; Loeschcke, Volker; Kristensen, Torsten Nygaard

    2010-01-01

    or 2 generations. These inbred lines were contrasted to non-inbred control lines. We investigated the effect of inbreeding and inbreeding rate in traits associated with fitness including heat, cold and desiccation stress resistance, egg-to-adult viability, development time, productivity, metabolic rate......The increased homozygosity due to inbreeding leads to expression of deleterious recessive alleles, which may cause inbreeding depression in small populations. The severity of inbreeding depression has been suggested to depend on the rate of inbreeding, with slower inbreeding being more effective...... and heat stress conditions. Reduced viability and increased developmental time were observed at stressful temperatures and inbreeding depression was on average more severe at stressful compared to benign temperatures...

  14. Patterns of mating-system evolution in hermaphroditic animals: correlations among selfing rate, inbreeding depression, and the timing of reproduction.

    NARCIS (Netherlands)

    Escobar, J.S.; Auld, J.R.; Correa, A.C.; Alonso, J.M.; Bony, Y.K.; Coutellec, M.-A.; Koene, J.M.; Pointier, J.-P.; Jarne, P.; David, P.

    2011-01-01

    In hermaphrodites, traits that influence the selfing rate can coevolve with inbreeding depression, leading to the emergence of evolutionary syndromes. Theory predicts a negative correlation between inbreeding depression and selfing rate across species. This prediction has only been examined and

  15. A major QTL affects temperature sensitive adult lethality and inbreeding depression in life span in Drosophila melanogaster

    NARCIS (Netherlands)

    Vermeulen, Cornelius J.; Bijlsma, R.; Loeschcke, Volker

    2008-01-01

    Background: The study of inbreeding depression has major relevance for many disciplines, including conservation genetics and evolutionary biology. Still, the molecular genetic basis of this phenomenon remains poorly characterised, as knowledge on the mechanistic causes of inbreeding depression and

  16. Inbreeding effects on palmar dermatoglyphic characters in three endogamous social groups of West Bengal, India.

    Science.gov (United States)

    Banik, S Datta

    2014-02-01

    The present study reports inbreeding effects on mean palmar dermatoglyphic characteristics: triradial count on palm, maximal atd angle, adt angle, td ridge count, ab ridge count, main line index (MLI) and ab ridge breadth. Samples were drawn from adult males belonging to three endogamous sections representing Hindu caste Telaga of Kharagpur (West Midnapore), Ansari Muslims of Nandigram (East Midnapore) and Sheik-Sunni Muslims of Braddhaman in West Bengal, India. Consistent trend of higher mean triradial number, adt angle, and lower mean td ridge count, ab ridge count, and ab ridge breadth was observed in inbred sections compared to their non-inbred relatives in three social groups. Copyright © 2013 Elsevier GmbH. All rights reserved.

  17. Allometric and non-allometric consequences of inbreeding on Drosophila melanogaster wings

    DEFF Research Database (Denmark)

    Trotta, Vincenzo; Cavicchi, Sandro; Guerra, Daniela

    2011-01-01

    Inbreeding is expected to increase the variability in size and shape within populations. The distinct effects of inbreeding on size and shape suggest that they are governed by different developmental pathways. One unresolved question is whether the non-allometric shape component is partially unco...

  18. Within and between population variation in inbreeding depression in the locally threatened perennial Scabiosa columbaria

    NARCIS (Netherlands)

    Angeloni, F.; Vergeer, P.; Wagemaker, C.A.M.; Ouborg, N.J.

    2014-01-01

    Inbreeding depression plays a central role within the conservation genetics paradigm. Until now inbreeding depression is incorporated into models of population viability as a mean value (e.g. number of lethal equivalents) for all traits in a population. In this study of the locally threatened

  19. Investigating Inbreeding Depression for Heat Stress Tolerance in the Model Organism "Drosophila Melanogaster"

    Science.gov (United States)

    Pedersen, Kamilla Sofie; Pedersen, Louise Dybdahl; Sorensen, Anders Christian; Nielsen, Anna Busch; Kristensen, Torsten Nygaard

    2012-01-01

    Mating between closely related individuals often causes reduced fitness, which is termed "inbreeding depression". Inbreeding is, therefore, a threat towards the persistence of animal and plant populations. Here we present methods and results from a practical for high-school and first-year university students and discuss learning outcomes…

  20. Telomere length reveals cumulative individual and transgenerational inbreeding effects in a passerine bird

    NARCIS (Netherlands)

    Bebbington, Kat; Spurgin, Lewis G.; Fairfield, Eleanor A.; Dugdale, Hannah L.; Komdeur, Jan; Burke, Terry; Richardson, David S.

    Inbreeding results in more homozygous offspring that should suffer reduced fitness, but it can be difficult to quantify these costs for several reasons. First, inbreeding depression may vary with ecological or physiological stress and only be detectable over long time periods. Second, parental

  1. Genetic Gain and Inbreeding from Genomic Selection in a Simulated Commercial Breeding Program for Perennial Ryegrass

    Directory of Open Access Journals (Sweden)

    Zibei Lin

    2016-03-01

    Full Text Available Genomic selection (GS provides an attractive option for accelerating genetic gain in perennial ryegrass ( improvement given the long cycle times of most current breeding programs. The present study used simulation to investigate the level of genetic gain and inbreeding obtained from GS breeding strategies compared with traditional breeding strategies for key traits (persistency, yield, and flowering time. Base population genomes were simulated through random mating for 60,000 generations at an effective population size of 10,000. The degree of linkage disequilibrium (LD in the resulting population was compared with that obtained from empirical studies. Initial parental varieties were simulated to match diversity of current commercial cultivars. Genomic selection was designed to fit into a company breeding program at two selection points in the breeding cycle (spaced plants and miniplot. Genomic estimated breeding values (GEBVs for productivity traits were trained with phenotypes and genotypes from plots. Accuracy of GEBVs was 0.24 for persistency and 0.36 for yield for single plants, while for plots it was lower (0.17 and 0.19, respectively. Higher accuracy of GEBVs was obtained for flowering time (up to 0.7, partially as a result of the larger reference population size that was available from the clonal row stage. The availability of GEBVs permit a 4-yr reduction in cycle time, which led to at least a doubling and trebling genetic gain for persistency and yield, respectively, than the traditional program. However, a higher rate of inbreeding per cycle among varieties was also observed for the GS strategy.

  2. A comparison of inbreeding Depression in Tropical and Widespread Drosophila Species

    DEFF Research Database (Denmark)

    Bechsgaard, Jesper Smærup; Hoffmann, Ary A; Sgró, Carla

    2013-01-01

    in 5 widespread and 5 tropical restricted species of Drosophila with aim of testing whether the two species groups suffered differently from inbreeding depression. The traits investigated wwere egg-to-adult viability, develpmental time and resistance to heat, vold and desiccation. Our results showed...... that levels of inbreeding depression were species and trait specific and did not differ between the species groups for stress resistance traits. However, for the life history traits developmental time and egg-to-adult viability, more inbreeding depression was observed in the tropical species. The results...... reported suggest that for life history traits tropical species of Drosophila will suffer more from inbreeding depression than widespread species in case of increases in the rate of inbreeding e.g. due to declines in population sizes....

  3. Higher harmonic flow coefficients of identified hadrons in Pb-Pb collisions at $\\sqrt{s_{\\rm NN}}$ = 2.76 TeV

    CERN Document Server

    Adam, Jaroslav; Aggarwal, Madan Mohan; Aglieri Rinella, Gianluca; Agnello, Michelangelo; Agrawal, Neelima; Ahammed, Zubayer; Ahmad, Shakeel; Ahn, Sang Un; Aiola, Salvatore; Akindinov, Alexander; Alam, Sk Noor; Silva De Albuquerque, Danilo; Aleksandrov, Dmitry; Alessandro, Bruno; Alexandre, Didier; Alfaro Molina, Jose Ruben; Alici, Andrea; Alkin, Anton; Alme, Johan; Alt, Torsten; Altinpinar, Sedat; Altsybeev, Igor; Alves Garcia Prado, Caio; An, Mangmang; Andrei, Cristian; Andrews, Harry Arthur; Andronic, Anton; Anguelov, Venelin; Anticic, Tome; Antinori, Federico; Antonioli, Pietro; Aphecetche, Laurent Bernard; Appelshaeuser, Harald; Arcelli, Silvia; Arnaldi, Roberta; Arnold, Oliver Werner; Arsene, Ionut Cristian; Arslandok, Mesut; Audurier, Benjamin; Augustinus, Andre; Averbeck, Ralf Peter; Azmi, Mohd Danish; Badala, Angela; Baek, Yong Wook; Bagnasco, Stefano; Bailhache, Raphaelle Marie; Bala, Renu; Balasubramanian, Supraja; Baldisseri, Alberto; Baral, Rama Chandra; Barbano, Anastasia Maria; 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Harris, John William; Harton, Austin Vincent; Hatzifotiadou, Despina; Hayashi, Shinichi; Heckel, Stefan Thomas; Hellbar, Ernst; Helstrup, Haavard; Herghelegiu, Andrei Ionut; Herrera Corral, Gerardo Antonio; Herrmann, Florian; Hess, Benjamin Andreas; Hetland, Kristin Fanebust; Hillemanns, Hartmut; Hippolyte, Boris; Horak, David; Hosokawa, Ritsuya; Hristov, Peter Zahariev; Hughes, Charles; Humanic, Thomas; Hussain, Nur; Hussain, Tahir; Hutter, Dirk; Hwang, Dae Sung; Ilkaev, Radiy; Inaba, Motoi; Incani, Elisa; Ippolitov, Mikhail; Irfan, Muhammad; Isakov, Vladimir; Ivanov, Marian; Ivanov, Vladimir; Izucheev, Vladimir; Jacak, Barbara; Jacazio, Nicolo; Jacobs, Peter Martin; Jadhav, Manoj Bhanudas; Jadlovska, Slavka; Jadlovsky, Jan; Jahnke, Cristiane; Jakubowska, Monika Joanna; Janik, Malgorzata Anna; Pahula Hewage, Sandun; Jena, Chitrasen; Jena, Satyajit; Jimenez Bustamante, Raul Tonatiuh; Jones, Peter Graham; Jusko, Anton; Kalinak, Peter; Kalweit, Alexander Philipp; Kang, Ju Hwan; Kaplin, Vladimir; Kar, Somnath; Karasu Uysal, Ayben; Karavichev, Oleg; Karavicheva, Tatiana; Karayan, Lilit; Karpechev, Evgeny; Kebschull, Udo Wolfgang; Keidel, Ralf; Keijdener, Darius Laurens; Keil, Markus; Khan, Mohammed Mohisin; Khan, Palash; Khan, Shuaib Ahmad; Khanzadeev, Alexei; Kharlov, Yury; Khatun, Anisa; Kileng, Bjarte; Kim, Do Won; Kim, Dong Jo; Kim, Daehyeok; Kim, Hyeonjoong; Kim, Jinsook; Kim, Jiyoung; Kim, Minwoo; Kim, Se Yong; Kim, Taesoo; Kirsch, Stefan; Kisel, Ivan; Kiselev, Sergey; Kisiel, Adam Ryszard; Kiss, Gabor; Klay, Jennifer Lynn; Klein, Carsten; Klein, Jochen; Klein-Boesing, Christian; Klewin, Sebastian; Kluge, Alexander; Knichel, Michael Linus; Knospe, Anders Garritt; Kobdaj, Chinorat; Kofarago, Monika; Kollegger, Thorsten; Kolozhvari, Anatoly; Kondratev, Valerii; Kondratyeva, Natalia; Kondratyuk, Evgeny; Konevskikh, Artem; Kopcik, Michal; Kour, Mandeep; Kouzinopoulos, Charalampos; Kovalenko, Oleksandr; Kovalenko, Vladimir; Kowalski, Marek; Koyithatta Meethaleveedu, Greeshma; Kralik, Ivan; Kravcakova, Adela; Krivda, Marian; Krizek, Filip; Kryshen, Evgeny; Krzewicki, Mikolaj; Kubera, Andrew Michael; Kucera, Vit; Kuhn, Christian Claude; Kuijer, Paulus Gerardus; Kumar, Ajay; Kumar, Jitendra; Kumar, Lokesh; Kumar, Shyam; Kurashvili, Podist; Kurepin, Alexander; Kurepin, Alexey; Kuryakin, Alexey; Kweon, Min Jung; Kwon, Youngil; La Pointe, Sarah Louise; La Rocca, Paola; Ladron De Guevara, Pedro; Lagana Fernandes, Caio; Lakomov, Igor; Langoy, Rune; Lapidus, Kirill; Lara Martinez, Camilo Ernesto; Lardeux, Antoine Xavier; Lattuca, Alessandra; Laudi, Elisa; Lea, Ramona; Leardini, Lucia; Lee, Seongjoo; Lehas, Fatiha; Lehner, Sebastian; Lemmon, Roy Crawford; Lenti, Vito; Leogrande, Emilia; Leon Monzon, Ildefonso; Leon Vargas, Hermes; Leoncino, Marco; Levai, Peter; Li, Shuang; Li, Xiaomei; Lien, Jorgen Andre; Lietava, Roman; Lindal, Svein; Lindenstruth, Volker; Lippmann, Christian; Lisa, Michael Annan; Ljunggren, Hans Martin; Lodato, Davide Francesco; Lonne, Per-Ivar; Loginov, Vitaly; 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Yin, Zhongbao; Yokoyama, Hiroki; Yoo, In-Kwon; Yoon, Jin Hee; Yurchenko, Volodymyr; Zaborowska, Anna; Zaccolo, Valentina; Zaman, Ali; Zampolli, Chiara; Correia Zanoli, Henrique Jose; Zaporozhets, Sergey; Zardoshti, Nima; Zarochentsev, Andrey; Zavada, Petr; Zavyalov, Nikolay; Zbroszczyk, Hanna Paulina; Zgura, Sorin Ion; Zhalov, Mikhail; Zhang, Haitao; Zhang, Xiaoming; Zhang, Yonghong; Chunhui, Zhang; Zhang, Zuman; Zhao, Chengxin; Zhigareva, Natalia; Zhou, Daicui; Zhou, You; Zhou, Zhuo; Zhu, Hongsheng; Zhu, Jianhui; Zichichi, Antonino; Zimmermann, Alice; Zimmermann, Markus Bernhard; Zinovjev, Gennady; Zyzak, Maksym

    2016-09-28

    The elliptic, triangular, quadrangular and pentagonal anisotropic flow coefficients for $\\pi^{\\pm}$, $\\mathrm{K}^{\\pm}$ and p+$\\overline{\\mathrm{p}}$ in Pb-Pb collisions at $\\sqrt{s_\\mathrm{{NN}}} = 2.76$ TeV were measured with the ALICE detector at the Large Hadron Collider. The results were obtained with the Scalar Product method, correlating the identified hadrons with reference particles from a different pseudorapidity region. Effects not related to the common event symmetry planes (non-flow) were estimated using correlations in pp collisions and were subtracted from the measurement. The obtained flow coefficients exhibit a clear mass ordering for transverse momentum ($p_{\\mathrm{T}}$) values below $\\approx$ 3 GeV/$c$. In the intermediate $p_{\\mathrm{T}}$ region ($3 < p_{\\mathrm{T}} < 6$ GeV/$c$), particles group at an approximate level according to the number of constituent quarks, suggesting that coalescence might be the relevant particle production mechanism in this region. The results for $p_{\\m...

  4. Higher harmonic flow coefficients of identified hadrons in Pb-Pb collisions at √{s_{NN}}=2.76 TeV

    Science.gov (United States)

    Adam, J.; Adamová, D.; Aggarwal, M. M.; Aglieri Rinella, G.; Agnello, M.; Agrawal, N.; Ahammed, Z.; Ahmad, S.; Ahn, S. U.; Aiola, S.; Akindinov, A.; Alam, S. N.; Albuquerque, D. S. D.; Aleksandrov, D.; Alessandro, B.; Alexandre, D.; Alfaro Molina, R.; Alici, A.; Alkin, A.; Alme, J.; Alt, T.; Altinpinar, S.; Altsybeev, I.; Alves Garcia Prado, C.; An, M.; Andrei, C.; Andrews, H. A.; Andronic, A.; Anguelov, V.; Antičić, T.; Antinori, F.; Antonioli, P.; Aphecetche, L.; Appelshäuser, H.; Arcelli, S.; Arnaldi, R.; Arnold, O. W.; Arsene, I. C.; Arslandok, M.; Audurier, B.; Augustinus, A.; Averbeck, R.; Azmi, M. D.; Badalà, A.; Baek, Y. W.; Bagnasco, S.; Bailhache, R.; Bala, R.; Balasubramanian, S.; Baldisseri, A.; Baral, R. C.; Barbano, A. M.; Barbera, R.; Barile, F.; Barnaföldi, G. G.; Barnby, L. S.; Barret, V.; Bartalini, P.; Barth, K.; Bartke, J.; Bartsch, E.; Basile, M.; Bastid, N.; Basu, S.; Bathen, B.; Batigne, G.; Batista Camejo, A.; Batyunya, B.; Batzing, P. C.; Bearden, I. G.; Beck, H.; Bedda, C.; Behera, N. K.; Belikov, I.; Bellini, F.; Bello Martinez, H.; Bellwied, R.; Belmont, R.; Belmont-Moreno, E.; Beltran, L. G. E.; Belyaev, V.; Bencedi, G.; Beole, S.; Berceanu, I.; Bercuci, A.; Berdnikov, Y.; Berenyi, D.; Bertens, R. A.; Berzano, D.; Betev, L.; Bhasin, A.; Bhat, I. R.; Bhati, A. K.; Bhattacharjee, B.; Bhom, J.; Bianchi, L.; Bianchi, N.; Bianchin, C.; Bielčík, J.; Bielčíková, J.; Bilandzic, A.; Biro, G.; Biswas, R.; Biswas, S.; Bjelogrlic, S.; Blair, J. T.; Blau, D.; Blume, C.; Bock, F.; Bogdanov, A.; Bøggild, H.; Boldizsár, L.; Bombara, M.; Bonora, M.; Book, J.; Borel, H.; Borissov, A.; Borri, M.; Bossú, F.; Botta, E.; Bourjau, C.; Braun-Munzinger, P.; Bregant, M.; Breitner, T.; Broker, T. A.; Browning, T. A.; Broz, M.; Brucken, E. J.; Bruna, E.; Bruno, G. E.; Budnikov, D.; Buesching, H.; Bufalino, S.; Buncic, P.; Busch, O.; Buthelezi, Z.; Butt, J. B.; Buxton, J. T.; Cabala, J.; Caffarri, D.; Cai, X.; Caines, H.; Calero Diaz, L.; Caliva, A.; Calvo Villar, E.; Camerini, P.; Carena, F.; Carena, W.; Carnesecchi, F.; Castillo Castellanos, J.; Castro, A. J.; Casula, E. A. R.; Ceballos Sanchez, C.; Cepila, J.; Cerello, P.; Cerkala, J.; Chang, B.; Chapeland, S.; Chartier, M.; Charvet, J. L.; Chattopadhyay, S.; Chattopadhyay, S.; Chauvin, A.; Chelnokov, V.; Cherney, M.; Cheshkov, C.; Cheynis, B.; Chibante Barroso, V.; Chinellato, D. D.; Cho, S.; Chochula, P.; Choi, K.; Chojnacki, M.; Choudhury, S.; Christakoglou, P.; Christensen, C. H.; Christiansen, P.; Chujo, T.; Chung, S. U.; Cicalo, C.; Cifarelli, L.; Cindolo, F.; Cleymans, J.; Colamaria, F.; Colella, D.; Collu, A.; Colocci, M.; Conesa Balbastre, G.; Conesa del Valle, Z.; Connors, M. E.; Contreras, J. G.; Cormier, T. M.; Corrales Morales, Y.; Cortés Maldonado, I.; Cortese, P.; Cosentino, M. R.; Costa, F.; Crkovska, J.; Crochet, P.; Cruz Albino, R.; Cuautle, E.; Cunqueiro, L.; Dahms, T.; Dainese, A.; Danisch, M. C.; Danu, A.; Das, D.; Das, I.; Das, S.; Dash, A.; Dash, S.; De, S.; De Caro, A.; de Cataldo, G.; de Conti, C.; de Cuveland, J.; De Falco, A.; De Gruttola, D.; De Marco, N.; De Pasquale, S.; De Souza, R. D.; Deisting, A.; Deloff, A.; Dénes, E.; Deplano, C.; Dhankher, P.; Di Bari, D.; Di Mauro, A.; Di Nezza, P.; Di Ruzza, B.; Diaz Corchero, M. A.; Dietel, T.; Dillenseger, P.; Divià, R.; Djuvsland, Ø.; Dobrin, A.; Domenicis Gimenez, D.; Dönigus, B.; Dordic, O.; Drozhzhova, T.; Dubey, A. K.; Dubla, A.; Ducroux, L.; Dupieux, P.; Ehlers, R. J.; Elia, D.; Endress, E.; Engel, H.; Epple, E.; Erazmus, B.; Erdemir, I.; Erhardt, F.; Espagnon, B.; Estienne, M.; Esumi, S.; Eulisse, G.; Eum, J.; Evans, D.; Evdokimov, S.; Eyyubova, G.; Fabbietti, L.; Fabris, D.; Faivre, J.; Fantoni, A.; Fasel, M.; Feldkamp, L.; Feliciello, A.; Feofilov, G.; Ferencei, J.; Fernández Téllez, A.; Ferreiro, E. G.; Ferretti, A.; Festanti, A.; Feuillard, V. J. G.; Figiel, J.; Figueredo, M. A. S.; Filchagin, S.; Finogeev, D.; Fionda, F. M.; Fiore, E. M.; Floris, M.; Foertsch, S.; Foka, P.; Fokin, S.; Fragiacomo, E.; Francescon, A.; Francisco, A.; Frankenfeld, U.; Fronze, G. G.; Fuchs, U.; Furget, C.; Furs, A.; Fusco Girard, M.; Gaardhøje, J. J.; Gagliardi, M.; Gago, A. M.; Gajdosova, K.; Gallio, M.; Galvan, C. D.; Gangadharan, D. R.; Ganoti, P.; Gao, C.; Garabatos, C.; Garcia-Solis, E.; Garg, K.; Gargiulo, C.; Gasik, P.; Gauger, E. F.; Germain, M.; Gheata, M.; Ghosh, P.; Ghosh, S. K.; Gianotti, P.; Giubellino, P.; Giubilato, P.; Gladysz-Dziadus, E.; Glässel, P.; Goméz Coral, D. M.; Gomez Ramirez, A.; Gonzalez, A. S.; Gonzalez, V.; González-Zamora, P.; Gorbunov, S.; Görlich, L.; Gotovac, S.; Grabski, V.; Grachov, O. A.; Graczykowski, L. K.; Graham, K. L.; Grelli, A.; Grigoras, A.; Grigoras, C.; Grigoriev, V.; Grigoryan, A.; Grigoryan, S.; Grinyov, B.; Grion, N.; Gronefeld, J. M.; Grosse-Oetringhaus, J. F.; Grosso, R.; Gruber, L.; Guber, F.; Guernane, R.; Guerzoni, B.; Gulbrandsen, K.; Gunji, T.; Gupta, A.; Gupta, R.; Guzman, I. B.; Haake, R.; Hadjidakis, C.; Haiduc, M.; Hamagaki, H.; Hamar, G.; Hamon, J. C.; Harris, J. W.; Harton, A.; Hatzifotiadou, D.; Hayashi, S.; Heckel, S. T.; Hellbär, E.; Helstrup, H.; Herghelegiu, A.; Herrera Corral, G.; Herrmann, F.; Hess, B. A.; Hetland, K. F.; Hillemanns, H.; Hippolyte, B.; Horak, D.; Hosokawa, R.; Hristov, P.; Hughes, C.; Humanic, T. J.; Hussain, N.; Hussain, T.; Hutter, D.; Hwang, D. S.; Ilkaev, R.; Inaba, M.; Incani, E.; Ippolitov, M.; Irfan, M.; Isakov, V.; Ivanov, M.; Ivanov, V.; Izucheev, V.; Jacak, B.; Jacazio, N.; Jacobs, P. M.; Jadhav, M. B.; Jadlovska, S.; Jadlovsky, J.; Jahnke, C.; Jakubowska, M. J.; Janik, M. A.; Jayarathna, P. H. S. Y.; Jena, C.; Jena, S.; Jimenez Bustamante, R. T.; Jones, P. G.; Jusko, A.; Kalinak, P.; Kalweit, A.; Kang, J. H.; Kaplin, V.; Kar, S.; Karasu Uysal, A.; Karavichev, O.; Karavicheva, T.; Karayan, L.; Karpechev, E.; Kebschull, U.; Keidel, R.; Keijdener, D. L. D.; Keil, M.; Mohisin Khan, M.; Khan, P.; Khan, S. A.; Khanzadeev, A.; Kharlov, Y.; Khatun, A.; Kileng, B.; Kim, D. W.; Kim, D. J.; Kim, D.; Kim, H.; Kim, J. S.; Kim, J.; Kim, M.; Kim, S.; Kim, T.; Kirsch, S.; Kisel, I.; Kiselev, S.; Kisiel, A.; Kiss, G.; Klay, J. L.; Klein, C.; Klein, J.; Klein-Bösing, C.; Klewin, S.; Kluge, A.; Knichel, M. L.; Knospe, A. G.; Kobdaj, C.; Kofarago, M.; Kollegger, T.; Kolojvari, A.; Kondratiev, V.; Kondratyeva, N.; Kondratyuk, E.; Konevskikh, A.; Kopcik, M.; Kour, M.; Kouzinopoulos, C.; Kovalenko, O.; Kovalenko, V.; Kowalski, M.; Koyithatta Meethaleveedu, G.; Králik, I.; Kravčáková, A.; Krivda, M.; Krizek, F.; Kryshen, E.; Krzewicki, M.; Kubera, A. M.; Kučera, V.; Kuhn, C.; Kuijer, P. G.; Kumar, A.; Kumar, J.; Kumar, L.; Kumar, S.; Kurashvili, P.; Kurepin, A.; Kurepin, A. B.; Kuryakin, A.; Kweon, M. J.; Kwon, Y.; La Pointe, S. L.; La Rocca, P.; Ladron de Guevara, P.; Lagana Fernandes, C.; Lakomov, I.; Langoy, R.; Lapidus, K.; Lara, C.; Lardeux, A.; Lattuca, A.; Laudi, E.; Lea, R.; Leardini, L.; Lee, S.; Lehas, F.; Lehner, S.; Lemmon, R. C.; Lenti, V.; Leogrande, E.; León Monzón, I.; León Vargas, H.; Leoncino, M.; Lévai, P.; Li, S.; Li, X.; Lien, J.; Lietava, R.; Lindal, S.; Lindenstruth, V.; Lippmann, C.; Lisa, M. A.; Ljunggren, H. M.; Lodato, D. F.; Loenne, P. I.; Loginov, V.; Loizides, C.; Lopez, X.; López Torres, E.; Lowe, A.; Luettig, P.; Lunardon, M.; Luparello, G.; Lupi, M.; Lutz, T. H.; Maevskaya, A.; Mager, M.; Mahajan, S.; Mahmood, S. M.; Maire, A.; Majka, R. D.; Malaev, M.; Maldonado Cervantes, I.; Malinina, L.; Mal'Kevich, D.; Malzacher, P.; Mamonov, A.; Manko, V.; Manso, F.; Manzari, V.; Mao, Y.; Marchisone, M.; Mareš, J.; Margagliotti, G. V.; Margotti, A.; Margutti, J.; Marín, A.; Markert, C.; Marquard, M.; Martin, N. A.; Martinengo, P.; Martínez, M. I.; Martínez García, G.; Martinez Pedreira, M.; Mas, A.; Masciocchi, S.; Masera, M.; Masoni, A.; Mastroserio, A.; Matyja, A.; Mayer, C.; Mazer, J.; Mazzilli, M.; Mazzoni, M. A.; Meddi, F.; Melikyan, Y.; Menchaca-Rocha, A.; Meninno, E.; Mercado Pérez, J.; Meres, M.; Mhlanga, S.; Miake, Y.; Mieskolainen, M. M.; Mikhaylov, K.; Milano, L.; Milosevic, J.; Mischke, A.; Mishra, A. N.; Mishra, T.; Miskowiec, D.; Mitra, J.; Mitu, C. M.; Mohammadi, N.; Mohanty, B.; Molnar, L.; Montaño Zetina, L.; Montes, E.; Moreira De Godoy, D. A.; Moreno, L. A. P.; Moretto, S.; Morreale, A.; Morsch, A.; Muccifora, V.; Mudnic, E.; Mühlheim, D.; Muhuri, S.; Mukherjee, M.; Mulligan, J. D.; Munhoz, M. G.; Münning, K.; Munzer, R. H.; Murakami, H.; Murray, S.; Musa, L.; Musinsky, J.; Naik, B.; Nair, R.; Nandi, B. K.; Nania, R.; Nappi, E.; Naru, M. U.; Natal da Luz, H.; Nattrass, C.; Navarro, S. R.; Nayak, K.; Nayak, R.; Nayak, T. K.; Nazarenko, S.; Nedosekin, A.; Negrao De Oliveira, R. A.; Nellen, L.; Ng, F.; Nicassio, M.; Niculescu, M.; Niedziela, J.; Nielsen, B. S.; Nikolaev, S.; Nikulin, S.; Nikulin, V.; Noferini, F.; Nomokonov, P.; Nooren, G.; Noris, J. C. C.; Norman, J.; Nyanin, A.; Nystrand, J.; Oeschler, H.; Oh, S.; Oh, S. K.; Ohlson, A.; Okatan, A.; Okubo, T.; Oleniacz, J.; Oliveira Da Silva, A. C.; Oliver, M. H.; Onderwaater, J.; Oppedisano, C.; Orava, R.; Oravec, M.; Ortiz Velasquez, A.; Oskarsson, A.; Otwinowski, J.; Oyama, K.; Ozdemir, M.; Pachmayer, Y.; Pagano, D.; Pagano, P.; Paić, G.; Pal, S. K.; Palni, P.; Pan, J.; Pandey, A. K.; Papikyan, V.; Pappalardo, G. S.; Pareek, P.; Park, W. J.; Parmar, S.; Passfeld, A.; Paticchio, V.; Patra, R. N.; Paul, B.; Pei, H.; Peitzmann, T.; Peng, X.; Pereira Da Costa, H.; Peresunko, D.; Perez Lezama, E.; Peskov, V.; Pestov, Y.; Petráček, V.; Petrov, V.; Petrovici, M.; Petta, C.; Piano, S.; Pikna, M.; Pillot, P.; Pimentel, L. O. D. L.; Pinazza, O.; Pinsky, L.; Piyarathna, D. B.; Ploskon, M.; Planinic, M.; Pluta, J.; Pochybova, S.; Podesta-Lerma, P. L. M.; Poghosyan, M. G.; Polichtchouk, B.; Poljak, N.; Poonsawat, W.; Pop, A.; Poppenborg, H.; Porteboeuf-Houssais, S.; Porter, J.; Pospisil, J.; Prasad, S. K.; Preghenella, R.; Prino, F.; Pruneau, C. A.; Pshenichnov, I.; Puccio, M.; Puddu, G.; Pujahari, P.; Punin, V.; Putschke, J.; Qvigstad, H.; Rachevski, A.; Raha, S.; Rajput, S.; Rak, J.; Rakotozafindrabe, A.; Ramello, L.; Rami, F.; Raniwala, R.; Raniwala, S.; Räsänen, S. S.; Rascanu, B. T.; Rathee, D.; Ravasenga, I.; Read, K. F.; Redlich, K.; Reed, R. J.; Rehman, A.; Reichelt, P.; Reidt, F.; Ren, X.; Renfordt, R.; Reolon, A. R.; Reshetin, A.; Reygers, K.; Riabov, V.; Ricci, R. A.; Richert, T.; Richter, M.; Riedler, P.; Riegler, W.; Riggi, F.; Ristea, C.; Rodríguez Cahuantzi, M.; Rodriguez Manso, A.; Røed, K.; Rogochaya, E.; Rohr, D.; Röhrich, D.; Ronchetti, F.; Ronflette, L.; Rosnet, P.; Rossi, A.; Roukoutakis, F.; Roy, A.; Roy, C.; Roy, P.; Rubio Montero, A. J.; Rui, R.; Russo, R.; Ryabinkin, E.; Ryabov, Y.; Rybicki, A.; Saarinen, S.; Sadhu, S.; Sadovsky, S.; Šafařík, K.; Sahlmuller, B.; Sahoo, P.; Sahoo, R.; Sahoo, S.; Sahu, P. K.; Saini, J.; Sakai, S.; Saleh, M. A.; Salzwedel, J.; Sambyal, S.; Samsonov, V.; Šándor, L.; Sandoval, A.; Sano, M.; Sarkar, D.; Sarkar, N.; Sarma, P.; Scapparone, E.; Scarlassara, F.; Schiaua, C.; Schicker, R.; Schmidt, C.; Schmidt, H. R.; Schmidt, M.; Schuchmann, S.; Schukraft, J.; Schutz, Y.; Schwarz, K.; Schweda, K.; Scioli, G.; Scomparin, E.; Scott, R.; Šefčík, M.; Seger, J. E.; Sekiguchi, Y.; Sekihata, D.; Selyuzhenkov, I.; Senosi, K.; Senyukov, S.; Serradilla, E.; Sevcenco, A.; Shabanov, A.; Shabetai, A.; Shadura, O.; Shahoyan, R.; Shangaraev, A.; Sharma, A.; Sharma, M.; Sharma, M.; Sharma, N.; Sheikh, A. I.; Shigaki, K.; Shou, Q.; Shtejer, K.; Sibiriak, Y.; Siddhanta, S.; Sielewicz, K. M.; Siemiarczuk, T.; Silvermyr, D.; Silvestre, C.; Simatovic, G.; Simonetti, G.; Singaraju, R.; Singh, R.; Singhal, V.; Sinha, T.; Sitar, B.; Sitta, M.; Skaali, T. B.; Slupecki, M.; Smirnov, N.; Snellings, R. J. M.; Snellman, T. W.; Song, J.; Song, M.; Song, Z.; Soramel, F.; Sorensen, S.; Sozzi, F.; Spiriti, E.; Sputowska, I.; Spyropoulou-Stassinaki, M.; Stachel, J.; Stan, I.; Stankus, P.; Stenlund, E.; Steyn, G.; Stiller, J. H.; Stocco, D.; Strmen, P.; Suaide, A. A. P.; Sugitate, T.; Suire, C.; Suleymanov, M.; Suljic, M.; Sultanov, R.; Šumbera, M.; Sumowidagdo, S.; Swain, S.; Szabo, A.; Szarka, I.; Szczepankiewicz, A.; Szymanski, M.; Tabassam, U.; Takahashi, J.; Tambave, G. J.; Tanaka, N.; Tarhini, M.; Tariq, M.; Tarzila, M. G.; Tauro, A.; Tejeda Muñoz, G.; Telesca, A.; Terasaki, K.; Terrevoli, C.; Teyssier, B.; Thäder, J.; Thakur, D.; Thomas, D.; Tieulent, R.; Tikhonov, A.; Timmins, A. R.; Toia, A.; Trogolo, S.; Trombetta, G.; Trubnikov, V.; Trzaska, W. H.; Tsuji, T.; Tumkin, A.; Turrisi, R.; Tveter, T. S.; Ullaland, K.; Uras, A.; Usai, G. L.; Utrobicic, A.; Vala, M.; Valencia Palomo, L.; Van Der Maarel, J.; Van Hoorne, J. W.; van Leeuwen, M.; Vanat, T.; Vande Vyvre, P.; Varga, D.; Vargas, A.; Vargyas, M.; Varma, R.; Vasileiou, M.; Vasiliev, A.; Vauthier, A.; Vázquez Doce, O.; Vechernin, V.; Veen, A. M.; Velure, A.; Vercellin, E.; Vergara Limón, S.; Vernet, R.; Vickovic, L.; Viinikainen, J.; Vilakazi, Z.; Villalobos Baillie, O.; Villatoro Tello, A.; Vinogradov, A.; Vinogradov, L.; Virgili, T.; Vislavicius, V.; Viyogi, Y. P.; Vodopyanov, A.; Völkl, M. A.; Voloshin, K.; Voloshin, S. A.; Volpe, G.; von Haller, B.; Vorobyev, I.; Vranic, D.; Vrláková, J.; Vulpescu, B.; Wagner, B.; Wagner, J.; Wang, H.; Wang, M.; Watanabe, D.; Watanabe, Y.; Weber, M.; Weber, S. G.; Weiser, D. F.; Wessels, J. P.; Westerhoff, U.; Whitehead, A. M.; Wiechula, J.; Wikne, J.; Wilk, G.; Wilkinson, J.; Willems, G. A.; Williams, M. C. S.; Windelband, B.; Winn, M.; Yalcin, S.; Yang, P.; Yano, S.; Yin, Z.; Yokoyama, H.; Yoo, I.-K.; Yoon, J. H.; Yurchenko, V.; Zaborowska, A.; Zaccolo, V.; Zaman, A.; Zampolli, C.; Zanoli, H. J. C.; Zaporozhets, S.; Zardoshti, N.; Zarochentsev, A.; Závada, P.; Zaviyalov, N.; Zbroszczyk, H.; Zgura, I. S.; Zhalov, M.; Zhang, H.; Zhang, X.; Zhang, Y.; Zhang, C.; Zhang, Z.; Zhao, C.; Zhigareva, N.; Zhou, D.; Zhou, Y.; Zhou, Z.; Zhu, H.; Zhu, J.; Zichichi, A.; Zimmermann, A.; Zimmermann, M. B.; Zinovjev, G.; Zyzak, M.

    2016-09-01

    The elliptic, triangular, quadrangular and pentagonal anisotropic flow coefficients for π±, K± and p+overline{p} in Pb-Pb collisions at √{s_{NN}}=2.76 TeV were measured with the ALICE detector at the Large Hadron Collider. The results were obtained with the Scalar Product method, correlating the identified hadrons with reference particles from a different pseudorapidity region. Effects not related to the common event symmetry planes (non-flow) were estimated using correlations in pp collisions and were subtracted from the measurement. The obtained flow coefficients exhibit a clear mass ordering for transverse momentum ( p T) values below ≈ 3 GeV/ c. In the intermediate p T region (3 fairly well by a hydrodynamical model (iEBE-VISHNU) that uses initial conditions generated by A Multi-Phase Transport model (AMPT) and describes the expansion of the fireball using a value of 0.08 for the ratio of shear viscosity to entropy density ( η/s), coupled to a hadronic cascade model (UrQMD). Finally, expectations from AMPT alone fail to quantitatively describe the measurements for all harmonics throughout the measured transverse momentum region. However, the comparison to the AMPT model highlights the importance of the late hadronic rescattering stage to the development of the observed mass ordering at low values of p T and of coalescence as a particle production mechanism for the particle type grouping at intermediate values of p T for all harmonics. [Figure not available: see fulltext.

  5. Morphological traits and inbreeding depression in Bracco Italiano dog breed

    Directory of Open Access Journals (Sweden)

    Francesca Cecchi

    2015-07-01

    Full Text Available This paper reports the first results of a survey on morphological traits in Bracco Italiano dog breed, and analyzes the effects of various levels of inbreeding on these measures. Traits were taken from 155 adult (mean age 4.18±2.60 years dogs (79 males and 76 females belonging to 57 different farms. For each animal, the following biometrical measurements were considered: height at withers (WH, height of chest (ChH, body length (BL, length at rump (RL, height at rump (RH, iliac width of rump (RIlW, ischiatic width of rump (RIsW, circumference of chest (ChC, circumference of cannon (CaC, length of ear (EL, and length of head (HL. The ratio of rump length/withers height (RL/WH, cannon circumference/chest circumference (CaC/ChC and head length/withers height (HL/WH were also calculated. ANOVA was used to test the differences between males and females and among farms in terms of morphological measurements and ratios. Significant differences between males and females were observed for many morphological traits. The measures coincided with what reported in the current breed standard, apart from the length of the rump, which was around ¼ of the withers height rather than the 1/3 required in the standard. No significant effect of inbreeding on conformation traits was observed.

  6. Thelytokous parthenogenesis and its consequences on inbreeding in an ant.

    Science.gov (United States)

    Pearcy, M; Hardy, O; Aron, S

    2006-05-01

    Thelytokous parthenogenesis, that is, the production of diploid daughters from unfertilized eggs, may involve various cytological mechanisms, each having a different impact on the genetic structure of populations. Here, we determined the cytological mechanism of thelytokous parthenogenesis and its impact on inbreeding in the ant Cataglyphis cursor, a species where queens use both sexual and asexual reproduction to produce, respectively, workers and new queens. It has been suggested that thelytokous parthenogenesis in C. cursor might have been selected for to face high queen mortality and, originally, to allow workers to replace the queen when she passes away. We first determined the mode of thelytokous parthenogenesis by comparing the rate of transition to homozygosity at four highly polymorphic loci to expectations under the different modes of parthenogenesis. Our data show that thelytoky is achieved through automictic parthenogenesis with central fusion. We then estimated the proportion of colonies headed by worker-produced queens in a natural population. We designed a model linking the observed homozygosity in queens to the proportion of queens produced by workers, based on the assumption that (i) parthenogenesis is automictic with central fusion and (ii) queen lineage is asexually produced, resulting in an increase of the inbreeding over generations, whereas workers are sexually produced and therefore not inbred. Our results indicate that more than 60% of the colonies should be headed by a worker-produced queen, suggesting that queen's lifespan is low in this species.

  7. Random inbreeding, isonymy, and population isolates in Argentina.

    Science.gov (United States)

    Dipierri, José; Rodríguez-Larralde, Alvaro; Barrai, Italo; Camelo, Jorge López; Redomero, Esperanza Gutiérrez; Rodríguez, Concepción Alonso; Ramallo, Virginia; Bronberg, Rubén; Alfaro, Emma

    2014-07-01

    Population isolates are an important tool in identifying and mapping genes of Mendelian diseases and complex traits. The geographical identification of isolates represents a priority from a genetic and health care standpoint. The purpose of this study is to analyze the spatial distribution of consanguinity by random isonymy (F ST) in Argentina and its relationship with the isolates previously identified in the country. F ST was estimated from the surname distribution of 22.6 million electors registered for the year 2001 in the 24 provinces, 5 geographical regions, and 510 departments of the country. Statistically significant spatial clustering of F ST was determined using the SaTScan V5.1 software. F ST exhibited a marked regional and departamental variation, showing the highest values towards the North and West of Argentina. The clusters of high consanguinity by random isonymy followed the same distribution. Recognized Argentinean genetic isolates are mainly localized at the north of the country, in clusters of high inbreeding. Given the availability of listings of surnames in high-capacity storage devices for different countries, estimating F ST from them can provide information on inbreeding for all levels of administrative subdivisions, to be used as a demographic variable for the identification of isolates within the country for public health purposes.

  8. Estimation of inbreeding using pedigree, 50k SNP chip genotypes and full sequence data in three cattle breeds

    DEFF Research Database (Denmark)

    Zhang, Qianqian; Calus, Mario P L; Guldbrandtsen, Bernt

    2015-01-01

    Background: Levels of inbreeding in cattle populations have increased in the past due to the use of a limited number of bulls for artificial insemination. High levels of inbreeding lead to reduced genetic diversity and inbreeding depression. Various estimators based on different sources, e...

  9. The environmental dependence of inbreeding depression in a wild bird population.

    Directory of Open Access Journals (Sweden)

    Marta Szulkin

    2007-10-01

    Full Text Available Inbreeding depression occurs when the offspring produced as a result of matings between relatives show reduced fitness, and is generally understood as a consequence of the elevated expression of deleterious recessive alleles. How inbreeding depression varies across environments is of importance for the evolution of inbreeding avoidance behaviour, and for understanding extinction risks in small populations. However, inbreeding-by-environment (IxE interactions have rarely been investigated in wild populations.We analysed 41 years of breeding events from a wild great tit (Parus major population and used 11 measures of the environment to categorise environments as relatively good or poor, testing whether these measures influenced inbreeding depression. Although inbreeding always, and environmental quality often, significantly affected reproductive success, there was little evidence for statistically significant I x E interactions at the level of individual analyses. However, point estimates of the effect of the environment on inbreeding depression were sometimes considerable, and we show that variation in the magnitude of the I x E interaction across environments is consistent with the expectation that this interaction is more marked across environmental axes with a closer link to overall fitness, with the environmental dependence of inbreeding depression being elevated under such conditions. Hence, our analyses provide evidence for an environmental dependence of the inbreeding x environment interaction: effectively an I x E x E.Overall, our analyses suggest that I x E interactions may be substantial in wild populations, when measured across relevant environmental contrasts, although their detection for single traits may require very large samples, or high rates of inbreeding.

  10. Strong inbreeding depression and individually variable mating system in the narrow endemic Erodium cazorlanum (Geraniaceae

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    Alonso, Conchita

    2013-06-01

    Full Text Available Angiosperms evolved different systems to attract effective pollinators while reducing selfing in hermaphroditic flowers. Selfing ability can be advantageous when pollinators and/or mates are scarce, although inbreeding depression may largely reduce those advantages. Recent comparative analyses suggested endemic species tend to evolve self-compatibility but a better understanding of the associated reproductive and genetic tradeoffs is required. Experimental hand-pollinations under greenhouse conditions were conducted to investigate the selfing ability and estimate inbreeding depression up to the offspring’ first reproductive event in Ero dium cazorlanum, a narrow endemic species restricted to dolomite outcrops in SE Spanish mountains. We found autonomous selfing ineffective. Further, when experimentally applied, pollen of the same flower produced significantly fewer fruits and seeds compared to geitonogamous and cross pollinations. The number of seeds per fruit was significantly higher after cross pollinations and strong inbreeding depression accumulated through the life-cycle. Interestingly, individual plants exhibited broad variation in selfing ability with six out of 14 individuals producing no seed after geitonogamy. Understanding the consequences of individual variation in self compatibility deserves further investigation in the field now that we know that strong inbreeding depression may limit recruitment of selfed progeny.Las Angiospermas han desarrollado diversos sistemas para atraer polinizadores eficientes y al mismo tiempo reducir la posibilidad de autopolinización asociada al hermafroditismo. La capacidad de autopolinización puede ser ventajosa en situaciones de escasez de polinizadores y/o individuos reproductores, beneficios que pueden reducirse ampliamente a causa de la depresión por endogamia. Análisis filogenéticos recientes indicaron que las especies endémicas tienden a presentar sistemas de autocompatibilidad, por tanto

  11. Inbreeding depression in maize populations and its effects on the obtention of promising inbred lines

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    Deoclecio Domingos Garbuglio

    2017-10-01

    Full Text Available Inbreeding can potentially be used for the development of inbred lines containing alleles of interest, but the genetic causes that control inbreeding depression are not completely known, and there are few studies found in the literature. The present study aimed to obtain estimates of inbreeding depression for eight traits in seven tropical maize populations, analyze the effects of inbreeding over generations and environments, and predict the behavior of inbred lines in future generation S? through linear regression methods. It was found that regardless of the base population used, prediction values could vary when the model was based on only 2 generations of inbreeding due to the environmental component. The influence of the environment in this type of study could be reduced when considering 3 generations of inbreeding, allowing greater precision in predicting the phenotypes of inbred lines. The use of linear regression was effective for inbred line prediction for the different agronomic traits evaluated. The use of 3 levels of inbreeding minimizes the effects of the environmental component in inbred line prediction for grain yield. GO-S was the most promising population for inbred line extraction.

  12. Inbreeding depresses sperm competitiveness, but not fertilization or mating success in male Tribolium castaneum

    Science.gov (United States)

    Michalczyk, Łukasz; Martin, Oliver Y.; Millard, Anna L.; Emerson, Brent C.; Gage, Matthew J. G.

    2010-01-01

    As populations decline to levels where reproduction among close genetic relatives becomes more probable, subsequent increases in homozygous recessive deleterious expression and/or loss of heterozygote advantage can lead to inbreeding depression. Here, we measure how inbreeding across replicate lines of the flour beetle Tribolium castaneum impacts on male reproductive fitness in the absence or presence of male–male competition. Effects on male evolution from mating pattern were removed by enforcing monogamous mating throughout. After inbreeding across eight generations, we found that male fertility in the absence of competition was unaffected. However, we found significant inbreeding depression of sperm competitiveness: non-inbred males won 57 per cent of fertilizations in competition, while inbred equivalents only sired 42 per cent. We also found that the P2 ‘offence’ role in sperm competition was significantly more depressed under inbreeding than sperm ‘defence’ (P1). Mating behaviour did not explain these differences, and there was no difference in the viability of offspring sired by inbred or non-inbred males. Sperm length variation was significantly greater in the ejaculates of inbred males. Our results show that male ability to achieve normal fertilization success was not depressed under strong inbreeding, but that inbreeding depression in these traits occurred when conditions of sperm competition were generated. PMID:20554548

  13. Effects of inbreeding on potential and realized immune responses in Tenebrio molitor.

    Science.gov (United States)

    Rantala, Markus J; Viitaniemi, Heidi; Roff, Derek A

    2011-06-01

    Although numerous studies on vertebrates suggest that inbreeding reduces their resistance against parasites and pathogens, studies in insects have found contradictory evidence. In this study we tested the effect of 1 generation of brother-sister mating (inbreeding) on potential and realized immune responses and other life-history traits in Tenebrio molitor. We found that inbreeding reduced adult mass, pre-adult survival and increased development time, suggesting that inbreeding reduced the condition of the adults and thus potentially made them more susceptible to physiological stress. However, we found no significant effect of inbreeding on the potential immune response (encapsulation response), but inbreeding reduced the realized immune response (resistance against the entomopathogenic fungi, Beauveria bassiana). There was a significant family effect on encapsulation response, but no family effect on the resistance against the entomopathogenic fungi. Given that this latter trait showed significant inbreeding depression and that the sample size for the family-effect analysis was small it is likely that the lack of a significant family effect is due to reduced statistical power, rather than the lack of a heritable basis to the trait. Our study highlights the importance of using pathogens and parasites in immunoecological studies.

  14. Influence of Maximum Inbreeding Avoidance under BLUP EBV Selection on Pinzgau Population Diversity

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    Radovan Kasarda

    2011-05-01

    Full Text Available Evaluated was effect of mating (random vs. maximum avoidance of inbreeding under BLUP EBV selection strategy. Existing population structure was under Monte Carlo stochastic simulation analyzed from the point to minimize increase of inbreeding. Maximum avoidance of inbreeding under BLUP selection resulted into comparable increase of inbreeding then random mating in average of 10 generation development. After 10 generations of simulation of mating strategy was observed ΔF= 6,51 % (2 sires, 5,20 % (3 sires, 3,22 % (4 sires resp. 2,94 % (5 sires. With increased number of sires selected, decrease of inbreeding was observed. With use of 4, resp. 5 sires increase of inbreeding was comparable to random mating with phenotypic selection. For saving of genetic diversity and prevention of population loss is important to minimize increase of inbreeding in small populations. Classical approach was based on balancing ratio of sires and dams in mating program. Contrariwise in the most of commercial populations small number of sires was used with high mating ratio.

  15. Effects of inbreeding on reproductive success, performance, litter size, and survival in captive red wolves (Canis rufus).

    Science.gov (United States)

    Rabon, David R; Waddell, William

    2010-01-01

    Captive-breeding programs have been widely used in the conservation of imperiled species, but the effects of inbreeding, frequently expressed in traits related to fitness, are nearly unavoidable in small populations with few founders. Following its planned extirpation in the wild, the endangered red wolf (Canis rufus) was preserved in captivity with just 14 founders. In this study, we evaluated the captive red wolf population for relationships between inbreeding and reproductive performance and fitness. Over 30 years of managed breeding, the level of inbreeding in the captive population has increased, and litter size has declined. Inbreeding levels were lower in sire and dam wolves that reproduced than in those that did not reproduce. However, there was no difference in the inbreeding level of actual litters and predicted litters. Litter size was negatively affected by offspring and paternal levels of inbreeding, but the effect of inbreeding on offspring survival was restricted to a positive influence. There was no apparent relationship between inbreeding and method of rearing offspring. The observable effects of inbreeding in the captive red wolf population currently do not appear to be a limiting factor in the conservation of the red wolf population. Additional studies exploring the extent of the effects of inbreeding will be required as inbreeding levels increase in the captive population.

  16. Habitat fragmentation, climate change, and inbreeding in plants.

    Science.gov (United States)

    Leimu, Roosa; Vergeer, Philippine; Angeloni, Francesco; Ouborg, N Joop

    2010-05-01

    Habitat fragmentation and climate change are recognized as major threats to biodiversity. The major challenge for present day plant populations is how to adapt and cope with altered abiotic and biotic environments caused by climate change, when at the same time adaptive and evolutionary potential is decreased as habitat fragmentation reduces genetic variation and increases inbreeding. Although the ecological and evolutionary effects of fragmentation and climate change have been investigated separately, their combined effects remained largely unexplored. In this review, we will discuss the individual and joint effects of habitat fragmentation and climate change on plants and how the abilities and ways in which plants can respond and cope with climate change may be compromised due to habitat fragmentation.

  17. Inbreeding depression in Solanum carolinense (Solanaceae, a species with a plastic self-incompatibility response

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    Keser Lidewij H

    2008-01-01

    Full Text Available Abstract Background Solanum carolinense (horsenettle is a highly successful weed with a gametophytic self-incompatibility (SI system. Previous studies reveal that the strength of SI in S. carolinense is a plastic trait, associated with particular S-alleles. The importance of this variation in self-fertility on the ability of horsenettle to found and establish new populations will depend, to a large extent, on the magnitude of inbreeding depression. We performed a series of greenhouse and field experiments to determine the magnitude of inbreeding depression in S. carolinense, whether inbreeding depression varies by family, and whether the estimates of inbreeding depression vary under field and greenhouse conditions. We performed a series of controlled self- and cross-pollinations on 16 genets collected from a large population in Pennsylvania to obtain progeny with different levels of inbreeding. We grew the selfed and outcrossed progeny in the greenhouse and under field conditions and recorded various measures of growth and reproductive output. Results In the greenhouse study we found (1 a reduction in flower, fruit and seed production per fruit in inbred (selfed progeny when compared to outbred (outcrossed progeny; (2 a reduction in growth of resprouts obtained from rhizome cuttings of selfed progeny; and (3 an increase in the ability to self-fertilize in the selfed progeny. In the field, we found that (1 outcrossed progeny produced more leaves than their selfed siblings; (2 herbivory seems to add little to inbreeding depression; and (3 outcrossed plants grew faster and were able to set more fruits than selfed plants. Conclusion Solanum carolinense experiences low levels of inbreeding depression under greenhouse conditions and slightly more inbreeding depression under our field conditions. The combined effects of low levels of inbreeding depression and plasticity in the strength of SI suggest that the production of selfed progeny may play an

  18. Evidence of high inbreeding in a population of the endangered giant anteater, Myrmecophaga tridactyla (Myrmecophagidae, from Emas National Park, Brazil

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    Rosane G. Collevatti

    2007-01-01

    Full Text Available We report the genetic structure, relatedness and mating structure of a population of the endangered giant anteater Myrmecophaga tridactyla Linnaeus, 1758 in the Emas National Park, Brazil, based on variability at five microsatellite loci. Additionally, we addressed the hypothesis that the M. tridactyla population studied has low levels of polymorphism and high levels of inbreeding and relatedness and that animals with overlapping home range are highly related. All five microsatellite loci displayed low levels of polymorphism and of expected and observed heterozygosity. The low level of polymorphism and high inbreeding showed by the population studied may be the outcome of high mortality and reduction in population size due to recurrent fire events in the Emas National Park, as reported in 1994. The reduction in population size may have led to a higher frequency of mating between closely related animals, augmented by the isolation of the population in the park because of the expansion of agricultural land and fragmentation of the Cerrado environment. The natural history of M. tridactyla and the phylopatric (sex-biased dispersal behavior of females should increase the effects of isolation and bottlenecking, decreasing gene flow and increasing inbreeding. However, the low levels of polymorphism found in this population may simply be due to the natural history and evolution of M. tridactyla as reported for other species. The genetic structure and dynamics of this population needs to be investigated more profoundly in order to provide sound data for the design of conservation strategies for M. tridactyla in the Emas National Park.

  19. Genome-scale data reveal that endemic Poecilia populations from small sulphidic springs display no evidence of inbreeding.

    Science.gov (United States)

    Brown, Anthony P; Greenway, Ryan; Morgan, Samuel; Quackenbush, Corey R; Giordani, Luca; Arias-Rodriguez, Lenin; Tobler, Michael; Kelley, Joanna L

    2017-10-01

    Populations with limited ranges can be highly vulnerable to changes in their environment and are, thus, of high conservation concern. Populations that experience human-induced range reductions are often highly inbred and lack genetic diversity, but it is unknown whether this is also the case for populations with naturally small ranges. The fishes Poecilia sulphuraria (listed as critically endangered) and Poecilia thermalis, which are endemic to small hydrogen sulphide-rich springs in southern Mexico, are examples of such populations with inherently small habitats. We used geometric morphometrics and population genetics to quantify phenotypic and genetic variation within and among two populations of P. sulphuraria and one population of P. thermalis. Principal component analyses revealed phenotypic and genetic differences among the populations. Evidence for inbreeding was low compared to populations that have undergone habitat reduction. The genetic data were also used to infer the demographic history of these populations to obtain estimates for effective population sizes and migration rates. Effective population sizes were large given the small habitats of these populations. Our results imply that these three endemic extremophile populations should each be considered separately for conservation purposes. Additionally, this study suggests that populations in naturally small habitats may have lower rates of inbreeding and higher genetic diversity than expected, and therefore may be better equipped to handle environmental perturbations than anticipated. We caution, however, that the inferred lack of inbreeding and the large effective population sizes could potentially be a result of colonization by genetically diverse ancestors. © 2017 John Wiley & Sons Ltd.

  20. Investigating inbreeding depression for heat stress tolerance in the model organism Drosophila melanogaster

    DEFF Research Database (Denmark)

    Pedersen, Kamilla Sofie; Pedersen, Louise Dybdahl; Sørensen, Anders Christian

    2012-01-01

    Mating between closely related individuals often causes reduced fitness, which is termed ‘inbreeding depression’. Inbreeding is, therefore, a threat towards the persistence of animal and plant populations. Here we present methods and results from a practical for high-school and first-year univers......Mating between closely related individuals often causes reduced fitness, which is termed ‘inbreeding depression’. Inbreeding is, therefore, a threat towards the persistence of animal and plant populations. Here we present methods and results from a practical for high-school and first...... into vials before exposure to 38°C heat stress in a water bath for 1 h. Half an hour later the number of comatose inbred and control flies were scored and chi-square statistic procedures were used to test for different degrees of heat stress tolerance between the two lines of flies. The practical introduces...

  1. Demographic consequences of inbreeding and outbreeding in Arnica montana: a field experiment.

    NARCIS (Netherlands)

    Luijten, S.H.; Kery, M.; Oostermeijer, J.G.B.; den Nijs, J.C.M.

    2002-01-01

    1. The genetic constitution of populations may significantly affect demography. Founder populations or isolated remnants may show inbreeding depression, while established populations can be strongly adapted to the local environment. Gene exchange between populations can lead to better performance if

  2. QTL mapping of inbreeding-related cold sensitivity and conditional lethality in Drosophila melanogaster

    DEFF Research Database (Denmark)

    Vermeulen, Corneel J.; Bijlsma, R.; Loeschcke, Volker

    2008-01-01

    of inbreeding-related and conditionally expressed lethality in Drosophila melanogaster. The lethal effect was triggered by exposure to a cold shock. We used a North Carolina crossing Design 3 to establish the mapping population, as well as to estimate the average dominance ratio and heritability. We found two......Inbreeding depression is a central theme within genetics, and is of specific interest for researchers within evolutionary and conservation genetics and animal and plant breeding. Inbreeding effects are thought to be caused by the joint expression of conditional and unconditional deleterious alleles....... Whenever the expression of deleterious alleles is conditional, this can result in extreme environmental sensitivity in certain inbred lineages. Analysis of conditional lethal effects can reveal some of the loci that are sensitive to inbreeding. We performed a QTL (quantitative trait locus) mapping study...

  3. The Self-Regulation Effect of Fertility Status on Inbreeding Aversion: When Fertile, Disgust Increases more in Response to Descriptions of One's Own than of Others' Inbreeding

    Directory of Open Access Journals (Sweden)

    Jan Antfolk

    2014-07-01

    Full Text Available The ovulatory shift modulates emotions related to female sexuality. Because fertility status only affects the individual's own opportunity cost, the adaptive value of this shift is expected to stem from self-regulation. To test this assumption we asked women to contemplate various inbreeding descriptions: 1 they themselves having sex with male relatives; 2 their sister having sex with their common male relatives; and 3 an unrelated woman having sex with her male relatives (in 1, but not 2 and 3, negative fitness consequences are affected by the participant's fertility. We dichotomized the dependent variable disgust (ceiling vs. non-ceiling and analyzed the interaction between fertility status and description type. The ovulatory shift was stronger in descriptions where they themselves were described as engaging in inbreeding. A smaller increase was also found in reactions to others engaging in inbreeding. We explain the latter effect as due to self-reflection.

  4. The self-regulation effect of fertility status on inbreeding aversion: when fertile, disgust increases more in response to descriptions of one's own than of others' inbreeding.

    Science.gov (United States)

    Antfolk, Jan; Lieberman, Debra; Albrecht, Anna; Santtila, Pekka

    2014-06-09

    The ovulatory shift modulates emotions related to female sexuality. Because fertility status only affects the individual's own opportunity cost, the adaptive value of this shift is expected to stem from self-regulation. To test this assumption we asked women to contemplate various inbreeding descriptions: 1) they themselves having sex with male relatives; 2) their sister having sex with their common male relatives; and 3) an unrelated woman having sex with her male relatives (in 1, but not 2 and 3, negative fitness consequences are affected by the participant's fertility). We dichotomized the dependent variable disgust (ceiling vs. non-ceiling) and analyzed the interaction between fertility status and description type. The ovulatory shift was stronger in descriptions where they themselves were described as engaging in inbreeding. A smaller increase was also found in reactions to others engaging in inbreeding. We explain the latter effect as due to self-reflection.

  5. Evaluation of 99 S/sub 1/ lines of maize for inbreeding depression

    International Nuclear Information System (INIS)

    Ahmad, M.; Khan, S.; Ahmad, F.; Shah, N.H.; Akhtar, N.

    2010-01-01

    The research was conducted to evaluate the performance of S1 lines for inbreeding depression regarding different parameters, using maize variety Azam. The maize variety was self-pollinated for one generation in spring season and in the next sowing season 99 S1 lines obtained from selfing was sown with a parental line. Days to silking, pollen-shedding, plant height , ear-height, ear-length, ear-diameter, number of ears/row, kernel rows/ear and 100 kernel weight showed inbreeding depression with varying degrees while yield kg/ha showed severe inbreeding depression with an average of 362.08 kg/ha. Average value of inbreeding depression for days to silking and pollen-shedding was calculated as 2.02 and 2.21 days, respectively. Average values of inbreeding depression for plant height and ear-height were recorded as 21.50 cm and 4.87 cm, respectively. While, for earlength, ear-diameter, number of ears/row, kernel rows/ear and 100 grain weight, the average value of inbreeding depression was recorded as 1.80 cm, 0.2 cm, 2.5, 2.11 and 3.89 g, respectively. Grain yield was positively and significantly correlated with plant height, ear height and yield components. Maturity traits were positively and significantly linked with each other. It is concluded that by subjecting the maize to self-pollination nearly all the lines were affected; however, some lines were affected severely and others tolerated inbreeding to some extent. The lines showing tolerance against inbreeding depression was selected for further maize breeding. (author)

  6. THE EFFECT OF INBREEDING ON THE EARLY PERFORMANCE OF FRESHWATER PRAWN, Macrobrachium rosenbergii

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    Imron Imron

    2009-06-01

    Full Text Available Inbreeding depression has often been considered to be responsible for the deterioration of performance in aquaculture species. Despite a crucial impact that may result from inbreeding depression, comprehensive information reviewing this subject is limited. This study was aimed to gain information on the effect of inbreeding on the early performance of freshwater prawn. The study was performed by comparing performance of inbred and outbred populations. Inbred population was established by brother-sister mating (inbreeding rate of 25% while the outbred population was formed by mating unrelated individuals. Several fitness and productivity related traits including survival, the rate of larval development, stage dispersion and growth of larvae were evaluated. Results suggest that inbred families performed poorer than that of the outbred in survival. However, inbreeding depression did not seem to occur in other traits including the rate of larval development, larval stage dispersion and growth. This study implies that to maintain genetic quality of farmed prawn stocks, inbreeding rate in farmed population must be controlled not to exceed that level. Implications that these findings may have on aquaculture practices and possible alternatives for the solutions are discussed.

  7. Mitigation of inbreeding while preserving genetic gain in genomic breeding programs for outbred plants.

    Science.gov (United States)

    Lin, Zibei; Shi, Fan; Hayes, Ben J; Daetwyler, Hans D

    2017-05-01

    Heuristic genomic inbreeding controls reduce inbreeding in genomic breeding schemes without reducing genetic gain. Genomic selection is increasingly being implemented in plant breeding programs to accelerate genetic gain of economically important traits. However, it may cause significant loss of genetic diversity when compared with traditional schemes using phenotypic selection. We propose heuristic strategies to control the rate of inbreeding in outbred plants, which can be categorised into three types: controls during mate allocation, during selection, and simultaneous selection and mate allocation. The proposed mate allocation measure GminF allocates two or more parents for mating in mating groups that minimise coancestry using a genomic relationship matrix. Two types of relationship-adjusted genomic breeding values for parent selection candidates ([Formula: see text]) and potential offspring ([Formula: see text]) are devised to control inbreeding during selection and even enabling simultaneous selection and mate allocation. These strategies were tested in a case study using a simulated perennial ryegrass breeding scheme. As compared to the genomic selection scheme without controls, all proposed strategies could significantly decrease inbreeding while achieving comparable genetic gain. In particular, the scenario using [Formula: see text] in simultaneous selection and mate allocation reduced inbreeding to one-third of the original genomic selection scheme. The proposed strategies are readily applicable in any outbred plant breeding program.

  8. Mating strategies with genomic information reduce rates of inbreeding in animal breeding schemes without compromising genetic gain.

    Science.gov (United States)

    Liu, H; Henryon, M; Sørensen, A C

    2017-04-01

    We tested the hypothesis that mating strategies with genomic information realise lower rates of inbreeding (∆F) than with pedigree information without compromising rates of genetic gain (∆G). We used stochastic simulation to compare ∆F and ∆G realised by two mating strategies with pedigree and genomic information in five breeding schemes. The two mating strategies were minimum-coancestry mating (MC) and minimising the covariance between ancestral genetic contributions (MCAC). We also simulated random mating (RAND) as a reference point. Generations were discrete. Animals were truncation-selected for a single trait that was controlled by 2000 quantitative trait loci, and the trait was observed for all selection candidates before selection. The criterion for selection was genomic-breeding values predicted by a ridge-regression model. Our results showed that MC and MCAC with genomic information realised 6% to 22% less ∆F than MC and MCAC with pedigree information without compromising ∆G across breeding schemes. MC and MCAC realised similar ∆F and ∆G. In turn, MC and MCAC with genomic information realised 28% to 44% less ∆F and up to 14% higher ∆G than RAND. These results indicated that MC and MCAC with genomic information are more effective than with pedigree information in controlling rates of inbreeding. This implies that genomic information should be applied to more than just prediction of breeding values in breeding schemes with truncation selection.

  9. The effects of inbreeding on sperm quality traits in captive‐bred lake trout, Salvelinus namaycush (Walbaum, 1972)

    DEFF Research Database (Denmark)

    Johnson, K.; Butts, I. A. E.; Smith, J. L.

    2015-01-01

    The effects of inbreeding in both captive and wild‐caught species and populations have been reported to affect a wide variety of life history traits. Recently, the effects of inbreeding on reproductive traits such as sperm quality have become a subject of particular interest for conservation...... biology, evolutionary ecology, and management of captive populations. This study investigated the effects of inbreeding on sperm quality in a captive population of experimentally inbred and outbred lake trout, Salvelinus namaycush. It was found for moderately to highly inbred males (males with half......‐sib and full‐sib parents, respectively), that sperm quality traits (velocity, motility, linearity, longevity, spermatocrit and morphology) showed no apparent inbreeding depression. The apparent lack of inbreeding effects on sperm quality traits may be due to several factors including (i) no inbreeding...

  10. Efficiency of selection, as measured by single nucleotide polymorphism variation, is dependent on inbreeding rate in Drosophila melanogaster

    DEFF Research Database (Denmark)

    Demontis, Ditte; Pertoldi, Cino; Loeschcke, Volker

    2009-01-01

    over homozygous individuals by natural selection, either by associative over-dominance or balancing selection, or a combination of both. Furthermore, we found a significant polynomial correlation between genetic variance and wing size and shape in the fast inbred lines. This was caused by a greater......It is often hypothesized that slow inbreeding causes less inbreeding depression than fast inbreeding at the same absolute level of inbreeding. Possible explanations for this phenomenon include the more efficient purging of deleterious alleles and more efficient selection for heterozygote...... genetic variance than fast inbreeding. These results increase our understanding of the genetic basis of the common observation that slow inbred lines express less inbreeding depression than fast inbred lines. In addition, this has more general implications for the importance of selection in maintaining...

  11. Reproductive Success and Inbreeding Differ in Fragmented Populations of Pinus rzedowskii and Pinus ayacahuite var. veitchii, Two Endemic Mexican Pines under Threat

    Directory of Open Access Journals (Sweden)

    Paty Castilleja Sánchez

    2016-08-01

    Full Text Available Seed production, quality, germination and seedling establishment are indicators of reproductive success in conifers. Monitoring of these parameters is essential to determine the viability of populations for the purposes of conservation. We analyze cone and seed traits as indicators of reproductive success in the endangered Rzedowski´s pine (Pinus rzedowskii (Madrigal et Caballero and near-threatened veitchii pine (Pinus ayacahuite var. veitchii (Shaw in west-central Michoacán, Mexico. These traits were systematically quantified and their variation assessed using Generalized Linear Mixed Models (GLMMs. We found that the reproductive success of Rzedowski’s pine seems to be critical, presenting low seed efficiency (17.10%, germination (5.0% and seedling establishment (27.7%, with high levels of inbreeding (0.79. In contrast, veitchii pine presents moderate seed efficiency (54.9%, high germination (71.5% and seedling establishment (84%–97% and low inbreeding (0.33. Reproductive indicators differed significantly among zones and populations for each species, where fragment sizes mainly affected seed production and efficiency. This result indicates that fragmentation has played a more important role in the reproductive success of Rzedowski’s pine than in veitchii pine, perhaps by limiting pollen flow among zones and populations and producing higher levels of inbreeding and lower seed efficiency in the former species. We propose a conservation strategy for these important pine species in order to increase their long-term genetic viability.

  12. Inbreeding of bottlenecked butterfly populations. Estimation using the likelihood of changes in marker allele frequencies.

    Science.gov (United States)

    Saccheri, I J; Wilson, I J; Nichols, R A; Bruford, M W; Brakefield, P M

    1999-03-01

    Polymorphic enzyme and minisatellite loci were used to estimate the degree of inbreeding in experimentally bottlenecked populations of the butterfly, Bicyclus anynana (Satyridae), three generations after founding events of 2, 6, 20, or 300 individuals, each bottleneck size being replicated at least four times. Heterozygosity fell more than expected, though not significantly so, but this traditional measure of the degree of inbreeding did not make full use of the information from genetic markers. It proved more informative to estimate directly the probability distribution of a measure of inbreeding, sigma2, the variance in the number of descendants left per gene. In all bottlenecked lines, sigma2 was significantly larger than in control lines (300 founders). We demonstrate that this excess inbreeding was brought about both by an increase in the variance of reproductive success of individuals, but also by another process. We argue that in bottlenecked lines linkage disequilibrium generated by the small number of haplotypes passing through the bottleneck resulted in hitchhiking of particular marker alleles with those haplotypes favored by selection. In control lines, linkage disequilibrium was minimal. Our result, indicating more inbreeding than expected from demographic parameters, contrasts with the findings of previous (Drosophila) experiments in which the decline in observed heterozygosity was slower than expected and attributed to associative overdominance. The different outcomes may both be explained as a consequence of linkage disequilibrium under different regimes of inbreeding. The likelihood-based method to estimate inbreeding should be of wide applicability. It was, for example, able to resolve small differences in sigma2 among replicate lines within bottleneck-size treatments, which could be related to the observed variation in reproductive viability.

  13. Recent breeding history of dog breeds in Sweden: modest rates of inbreeding, extensive loss of genetic diversity and lack of correlation between inbreeding and health.

    Science.gov (United States)

    Jansson, M; Laikre, L

    2014-04-01

    One problem in modern dogs is a high occurrence of physical diseases, defects and disorders. Many breeds exhibit physical problems that affect individual dogs throughout life. A potential cause of these problems is inbreeding that is known to reduce the viability of individuals. We investigated the possible correlation between recent inbreeding and health problems in dogs and used studbook data from 26 breeds provided by the Swedish Kennel Club for this purpose. The pedigrees date back to the mid-20th century and comprise 5-10 generations and 1 000-50 000 individuals per pedigree over our study period of 1980-2010. We compared levels of inbreeding and loss of genetic variation measured in relation to the number of founding animals during this period in the investigated dog breeds that we classified as 'healthy' (11 breeds) or 'unhealthy' (15) based on statistics on the extent of veterinary care obtained from Sweden's four largest insurance companies for pets. We found extensive loss of genetic variation and moderate levels of recent inbreeding in all breeds examined, but no strong indication of a difference in these parameters between healthy versus unhealthy breeds over this period. Thus, recent breeding history with respect to rate of inbreeding does not appear to be a main cause of poor health in the investigated dog breeds in Sweden. We identified both strengths and weaknesses of the dog pedigree data important to consider in future work of monitoring and conserving genetic diversity of dog breeds. © 2013 The Authors Journal of Animal Breeding and Genetics Published by Blackwell Verlag GmbH.

  14. Extra-group mating increases inbreeding risk in a cooperatively breeding bird.

    Science.gov (United States)

    Harrison, X A; York, J E; Cram, D L; Young, A J

    2013-11-01

    In many cooperatively breeding species, females mate extra-group, the adaptive value of which remains poorly understood. One hypothesis posits that females employ extra-group mating to access mates whose genotypes are more dissimilar to their own than their social mates, so as to increase offspring heterozygosity. We test this hypothesis using life history and genetic data from 36 cooperatively breeding white-browed sparrow weaver (Plocepasser mahali) groups. Contrary to prediction, a dominant female's relatedness to her social mate did not drive extra-group mating decisions and, moreover, extra-group mating females were significantly more related to their extra-group sires than their social mates. Instead, dominant females were substantially more likely to mate extra-group when paired to a dominant male of low heterozygosity, and their extra-group mates (typically dominants themselves) were significantly more heterozygous than the males they cuckolded. The combined effects of mating with extra-group males of closer relatedness, but higher heterozygosity resulted in extra-group-sired offspring that were no more heterozygous than their within-group-sired half-siblings. Our findings are consistent with a role for male-male competition in driving extra-group mating and suggest that the local kin structure typical of cooperative breeders could counter potential benefits to females of mating extra-group by exposing them to a risk of inbreeding. © 2013 John Wiley & Sons Ltd.

  15. Consequences of inbreeding and reduced genetic variation on tolerance to cadmium stress in the midge Chironomus riparius

    International Nuclear Information System (INIS)

    Nowak, Carsten; Jost, Daniel; Vogt, Christian; Oetken, Matthias; Schwenk, Klaus; Oehlmann, Joerg

    2007-01-01

    Inbreeding and loss of genetic variation are considered to be major threats to small and endangered populations. The reduction of fitness due to inbreeding is believed to be more severe under stressful environmental conditions. We generated nine strains of the ecotoxicological model organism Chironomus riparius of different inbreeding levels in order to test the hypothesis that the inbreeding level and thus the degree of genome-wide homozygosity influences the life-history under cadmium exposure. Therefore, midge populations were exposed to a gradient of sediment-bound cadmium. The level of genetic variation in the used strains was assessed using microsatellite markers. In the life-cycle tests, inbreeding reduced fitness within C. riparius populations both under control and stressed conditions. However, differences between genetically diverse and impoverished strains were greatest at high cadmium exposure. Overall, inbreeding effects were not only dependent on cadmium concentrations in the sediment, but also on the life-history trait investigated. While some parameters where only affected by inbreeding, others were altered by both, inbreeding and cadmium. For the larval developmental time, a significant interaction was found between inbreeding and cadmium stress. While all strains showed a similar developmental time under control conditions, high rates of inbreeding led to a significantly delayed emergence time under high cadmium concentrations, resulting in longer generation periods and reduced population growth rates as population-relevant effects. The results show, that bioassays with C. riparius are affected by the level of inbreeding within Chironomus test strains. Pollution stress is therefore likely to affect the survival of rare and endangered populations more severe than that of large and genetically diverse ones

  16. A case of inbreeding in the African Wild Dog Lycaon pictus in the Kruger National Park

    Directory of Open Access Journals (Sweden)

    A. Reich

    1978-09-01

    Full Text Available An observed case of inbreeding in a pack ot wild dogs Lycaon pictus in the Kruger National Park, Republic of South Africa, provides evidence for the phenomenon of dominance reversal in this species. This is believed to be the first recorded instance of inbreeding in Lycaon. Emigration of subordinate females from established packs of wild dogs has been documented in the Serengeti National Park and Ngorongoro Conservation Area in northern Tanzania, as well as in the Kruger National Park. However, the newly subordinate (ex-dominant female in the pack in which inbreeding has occurred has not emigrated in the 16 months since the change in her status. A possible explanation for this behaviour is given. As a result of this reversal, the pack contains at least two females capable of breeding, the subordinate of which is at least two years older than the dominant. This is considered the first record of such a breeding structure in Lycaon.

  17. Genomic Variation of Inbreeding and Ancestry in the Remaining Two Isle Royale Wolves.

    Science.gov (United States)

    Hedrick, Philip W; Kardos, Marty; Peterson, Rolf O; Vucetich, John A

    2017-03-01

    Inbreeding, relatedness, and ancestry have traditionally been estimated with pedigree information, however, molecular genomic data can provide more detailed examination of these properties. For example, pedigree information provides estimation of the expected value of these measures but molecular genomic data can estimate the realized values of these measures in individuals. Here, we generate the theoretical distribution of inbreeding, relatedness, and ancestry for the individuals in the pedigree of the Isle Royale wolves, the first examination of such variation in a wild population with a known pedigree. We use the 38 autosomes of the dog genome and their estimated map lengths in our genomic analysis. Although it is known that the remaining wolves are highly inbred, closely related, and descend from only 3 ancestors, our analyses suggest that there is significant variation in the realized inbreeding and relatedness around pedigree expectations. For example, the expected inbreeding in a hypothetical offspring from the 2 remaining wolves is 0.438 but the realized 95% genomic confidence interval is from 0.311 to 0.565. For individual chromosomes, a substantial proportion of the whole chromosomes are completely identical by descent. This examination provides a background to use when analyzing molecular genomic data for individual levels of inbreeding, relatedness, and ancestry. The level of variation in these measures is a function of the time to the common ancestor(s), the number of chromosomes, and the rate of recombination. In the Isle Royale wolf population, the few generations to a common ancestor results in the high variance in genomic inbreeding. © The American Genetic Association 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  18. Risk assessment of inbreeding and outbreeding depression in a captive-breeding program.

    Science.gov (United States)

    Rollinson, Njal; Keith, Dave M; Houde, Aimee Lee S; Debes, Paul V; McBride, Meghan C; Hutchings, Jeffrey A

    2014-04-01

    Captive-breeding programs can be implemented to preserve the genetic diversity of endangered populations such that the controlled release of captive-bred individuals into the wild may promote recovery. A common difficulty, however, is that programs are founded with limited wild broodstock, and inbreeding can become increasingly difficult to avoid with successive generations in captivity. Program managers must choose between maintaining the genetic purity of populations, at the risk of inbreeding depression, or interbreeding populations, at the risk of outbreeding depression. We evaluate these relative risks in a captive-breeding program for 3 endangered populations of Atlantic salmon (Salmo salar). In each of 2 years, we released juvenile F(1) and F(2) interpopulation hybrids, backcrosses, as well as inbred and noninbred within-population crosstypes into 9 wild streams. Juvenile size and survival was quantified in each year. Few crosstype effects were observed, but interestingly, the relative fitness consequences of inbreeding and outbreeding varied from year to year. Temporal variation in environmental quality might have driven some of these annual differences, by exacerbating the importance of maternal effects on juvenile fitness in a year of low environmental quality and by affecting the severity of inbreeding depression differently in different years. Nonetheless, inbreeding was more consistently associated with a negative effect on fitness, whereas the consequences of outbreeding were less predictable. Considering the challenges associated with a sound risk assessment in the wild and given that the effect of inbreeding on fitness is relatively predictable, we suggest that risk can be weighted more strongly in terms of the probable outcome of outbreeding. Factors such as genetic similarities between populations and the number of generations in isolation can sometimes be used to assess outbreeding risk, in lieu of experimentation. © 2014 Society for

  19. RELATION OF INBREEDING OF HORSES OF THOROUGHBRED BREED WITH DEGREE OF HOMOZYGOSITY OF MICROSATELLITE LOCI OF DNA

    Directory of Open Access Journals (Sweden)

    Melnyk О.V.

    2013-09-01

    Full Text Available The degree of homozygosity of some 39 Thoroughbred horses was estimated from microsatellite analysis data. The power of inbreeding was detected towards horse pedigree. We suggested the use of genetic analysis of microsatellite loci of DNA for the determination of actual level of inbreeding.

  20. A strategy analysis for genetic association studies with known inbreeding

    Directory of Open Access Journals (Sweden)

    del Giacco Stefano

    2011-07-01

    Full Text Available Abstract Background Association studies consist in identifying the genetic variants which are related to a specific disease through the use of statistical multiple hypothesis testing or segregation analysis in pedigrees. This type of studies has been very successful in the case of Mendelian monogenic disorders while it has been less successful in identifying genetic variants related to complex diseases where the insurgence depends on the interactions between different genes and the environment. The current technology allows to genotype more than a million of markers and this number has been rapidly increasing in the last years with the imputation based on templates sets and whole genome sequencing. This type of data introduces a great amount of noise in the statistical analysis and usually requires a great number of samples. Current methods seldom take into account gene-gene and gene-environment interactions which are fundamental especially in complex diseases. In this paper we propose to use a non-parametric additive model to detect the genetic variants related to diseases which accounts for interactions of unknown order. Although this is not new to the current literature, we show that in an isolated population, where the most related subjects share also most of their genetic code, the use of additive models may be improved if the available genealogical tree is taken into account. Specifically, we form a sample of cases and controls with the highest inbreeding by means of the Hungarian method, and estimate the set of genes/environmental variables, associated with the disease, by means of Random Forest. Results We have evidence, from statistical theory, simulations and two applications, that we build a suitable procedure to eliminate stratification between cases and controls and that it also has enough precision in identifying genetic variants responsible for a disease. This procedure has been successfully used for the beta-thalassemia, which is

  1. Metabolomic signatures of inbreeding at benign and stressful temperatures in Drosophila melanogaster

    DEFF Research Database (Denmark)

    Pedersen, Kamilla Sofie; Kristensen, Torsten Nygaard; Loeschcke, Volker

    2008-01-01

    to an increased between-line variation in metabolite profiles compared to outbred lines. In contrast to previous observations revealing interactions between inbreeding and environmental stress on gene expression patterns and life-history traits, the effect of inbreeding on the metabolite profile was similar...... and five inbred lines were studied by nuclear magnetic resonance spectroscopy after exposure to benign temperature, heat stress, or cold stress. In both the absence and the presence of temperature stress, metabolite levels were significantly different among inbred and outbred lines. The major effect...

  2. Distribution of individual inbreeding coefficients, relatedness and influence of stocking on native anadromous brown trout ( Salmo trutta ) population structure

    DEFF Research Database (Denmark)

    Ruzzante, D.E.; Hansen, Michael Møller; Meldrup, Dorte

    2001-01-01

    We examined polymorphism at seven microsatellite loci in 4023 brown trout (Salmo trutta) collected from 32 tributaries to the Limfjord, Denmark (similar to 200 km) and from two hatcheries used for stocking. Populations differ in their estimated sizes and stocking histories. Mean individual...... hypothesis that stocking has had no impact on population structure but the relatively high proportion of locally assigned trout in populations where stocking with domestic fish no longer takes place suggests limited long-term success of stocking....... origin but this proportion varies regionally, with rivers in the western area of the Limfjord showing a relatively high (mean 88%) and those in the eastern area showing a relatively low (mean 72%) proportion of locally assigned trout. These results can be interpreted as reflecting stocking impact. Also...

  3. Heat stress but not inbreeding affects offensive sperm competitiveness in Callosobruchus maculatus.

    Science.gov (United States)

    Lieshout, Emile; Tomkins, Joseph L; Simmons, Leigh W

    2013-09-01

    Environmental and genetic stress have well-known detrimental effects on ejaculate quality, but their concomitant effect on male fitness remains poorly understood. We used competitive fertilization assays to expose the effects of stress on offensive sperm competitive ability in the beetle Callosobruchus maculatus, a species where ejaculates make up more than 5% of male body mass. To examine the effects of environmental and genetic stress, males derived from outcrosses or sib matings were heat shocked at 50°C for 50 min during the pupal stage, while their siblings were maintained at a standard rearing temperature of 28°C. Heat-shocked males achieved only half the offensive paternity success of their siblings. While this population exhibited inbreeding depression in body size, sperm competitiveness was unaffected by inbreeding, nor did the effect of heat shock stress on sperm competitiveness depend on inbreeding status. In contrast, pupal emergence success was increased by 34% among heat-stressed individuals, regardless of their inbreeding status. Heat-shocked males' ejaculate size was 19% reduced, but they exhibited 25% increased mating duration in single mating trials. Our results highlight both the importance of stress in postcopulatory sexual selection, and the variability among stressors in affecting male fitness.

  4. Effects of seed size, inbreeding and maternal sex on offspring fitness in gynodioecious Plantago coronopus

    NARCIS (Netherlands)

    Koelewijn, H.P.; Damme, van J.M.M.

    2005-01-01

    1 Male steriles (MS) must have a fitness advantage relative to hermaphrodites (H) if they are to be maintained in gynodioecious species. We report experiments in which we disentangle the relative contributions of seed size, inbreeding and maternal sex to the fitness advantage of male steriles in

  5. Rate of inbreeding and effective population size in four major South ...

    African Journals Online (AJOL)

    huis

    Netherlands, New Zealand, Switzerland and the United States. Semen from Taurus, the local AI company, is also used extensively in the South African dairy industry. Literature estimates of rate of inbreeding and effective population size are not currently available for the South African dairy cattle breeds even though the.

  6. Extreme temperatures increase the deleterious consequences of inbreeding under laboratory and semi-natural conditions

    DEFF Research Database (Denmark)

    Kristensen, Torsten Nygård; Barker, J. Stuart F.; Pedersen, Kamilla Sofie

    2008-01-01

    The majority of experimental studies of the effects of population bottlenecks on fitness are performed under laboratory conditions, which do not account for the environmental complexity that populations face in nature. In this study, we test inbreeding depression in multiple replicates of inbred ...

  7. Genetic variation of inbreeding depression among floral and fitness traits in Silene nutans

    DEFF Research Database (Denmark)

    Thiele, Jan; Hansen, Thomas Møller; Siegismund, Hans Redlef

    2010-01-01

    The magnitude and variation of inbreeding depression (ID) within populations is important for the evolution and maintenance of mixed mating systems. We studied ID and its genetic variation in a range of floral and fitness traits in a small and large population of the perennial herb Silene nutans,...

  8. Variation in the strength of inbreeding depression across environments: effects of stress and density dependence.

    Science.gov (United States)

    Yun, Li; Agrawal, Aneil F

    2014-12-01

    In what types of environments should we expect to find strong inbreeding depression? Previous studies indicate that inbreeding depression, δ, is positively correlated with the stressfulness of the environment in which it is measured. However, it remains unclear why stress, per se, should increase δ. To our knowledge, only "competitive stress" has a logical connection to δ. Through competition for resources, better quality (outbred) individuals make the environment worse for lower quality (inbred) individuals, accentuating the differences between them. For this reason, we expect inbreeding depression to be stronger in environments where the fitness of individuals is more sensitive to the presence of conspecifics (i.e., where fitness is more density dependent). Indeed, some studies suggest a role for competition within environments, but this idea has not been tested in the context of understanding variation in δ across environments. Using Drosophila melanogaster, we estimated δ for viability in 22 different environments. These environments were simultaneously characterized for (1) stressfulness and (2) density dependence. Although stress and density dependence are moderately correlated with each other, inbreeding depression is much more strongly correlated with density dependence. These results suggest that mean selection across the genome is stronger in environments where competition is intense, rather than in environments that are stressful for other reasons. © 2014 The Author(s). Evolution © 2014 The Society for the Study of Evolution.

  9. The effects of inbreeding and heat stress on male sterility in Drosophila melanogaster

    DEFF Research Database (Denmark)

    Pedersen, Louise Dybdahl; Pedersen, Asger Roer; Bijlsma, Kuke

    2011-01-01

    in benign and stressful environments using Drosophila melanogaster as a model organism. Male sterility was compared in 21 inbred lines and five non-inbred control lines at 25.0 and 29.0 °C. The effect of inbreeding on sterility was significant only at 29.0 °C. This stress-induced increase in sterility...

  10. Effects of seed size, inbreeding and maternal sex on offspring fitness in gynodioecious Plantago coronopus

    NARCIS (Netherlands)

    Koelewijn, H.P.; Van Damme, J.M.M.

    2005-01-01

    Male steriles (MS) must have a fitness advantage relative to hermaphrodites (H) if they are to be maintained in gynodioecious species. We report experiments in which we disentangle the relative contributions of seed size, inbreeding and maternal sex to the fitness advantage of male steriles in

  11. Inbreeding and gene flow : the population genetics of plant species in fragmented landscapes

    NARCIS (Netherlands)

    Mix, Carolin

    2006-01-01

    Habitat fragmentation has been recognized as one of the major threats to plant population persistence. Fragmented small and isolated populations are expected to be seriously affected by inbreeding and genetic drift. Gene flow through seed and pollen dispersal may counterbalance the negative

  12. Generalization of the QSTframework in hierarchically structured populations: Impacts of inbreeding and dominance.

    Science.gov (United States)

    Cubry, Philippe; Scotti, Ivan; Oddou-Muratorio, Sylvie; Lefèvre, François

    2017-11-01

    Q ST is a differentiation parameter based on the decomposition of the genetic variance of a trait. In the case of additive inheritance and absence of selection, it is analogous to the genic differentiation measured on individual loci, F ST . Thus, Q ST -F ST comparison is used to infer selection: selective divergence when Q ST  > F ST , or convergence when Q ST  definition of Q-statistics was extended to two-level hierarchical population structures with Hardy-Weinberg equilibrium. Here, we generalize the Q-statistics framework to any hierarchical population structure. First, we developed the analytical definition of hierarchical Q-statistics for populations not at Hardy-Weinberg equilibrium. We show that the Q-statistics values obtained with the Hardy-Weinberg definition are lower than their corresponding F-statistics when F IS  > 0 (higher when F IS  framework in a hierarchical population structure. We show that, while differentiation at the lower hierarchical level (Q SR ) is a monotonic function of migration, differentiation at the upper level (Q RT ) is not. In the case of additive inheritance, we show that inbreeding inflates the variance of Q RT , which can increase the frequency of Q RT  > F RT cases. We also show that dominance drastically reduces Q-statistics below F-statistics for any level of the hierarchy. Therefore, high values of Q-statistics are good indicators of selection, but low values are not in the case of dominance. © 2017 John Wiley & Sons Ltd.

  13. Anther-stigma separation is associated with inbreeding depression in Datura stramonium, a predominantly self-fertilizing annual.

    Science.gov (United States)

    Stone, Judy L; Motten, Alexander F

    2002-11-01

    Genetically based variation in outcrossing rate generates lineages within populations that differ in their history of inbreeding. According to some models, mating-system modifiers in such populations will demonstrate both linkage and identity disequilibrium with fitness loci, resulting in lineage-specific inbreeding depression. Other models assert that differences among families in levels of inbreeding depression are mainly attributable to random accumulation of genetic load, unrelated to variation at mating-system loci. We measured female reproductive success of selfed and outcrossed progeny from naturally occurring lineages of Datura stramonium, a predominantly self-fertilizing annual weed that has heritable variation in stigma-anther separation, a trait that influences selfing rates. Progeny from inbred lineages (as identified by high degree of anther-stigma overlap) showed equal levels of seed production, regardless of cross type. Progeny from mixed lineages (as identified by relatively high separation between anthers and stigma) showed moderate levels of inbreeding depression. We found a significant correlation between anther-stigma separation and relative fitness of selfed and outcrossed progeny, suggesting that family-level inbreeding depression may be related to differences among lineages in inbreeding history in this population. Negative inbreeding depression in putatively inbred lineages may be due in part to additive effects or to epistatic interactions among loci.

  14. Seasonal stress drives predictable changes in inbreeding depression in field-tested captive populations of Drosophila melanogaster.

    Science.gov (United States)

    Enders, Laramy S; Nunney, Leonard

    2012-09-22

    Recent meta-analyses conducted across a broad range of taxa have demonstrated a strong linear relationship between the change in magnitude of inbreeding depression under stress and stress level, measured as fitness loss in outbred individuals. This suggests that a general underlying response may link stress and inbreeding depression. However, this relationship is based primarily on laboratory data, and it is unknown whether natural environments with multiple stressors and fluctuating stress levels alter how stress affects inbreeding depression. To test whether the same pattern persists in the field, we investigated the effect of seasonal variation on stress level and inbreeding depression in a 3-year field study measuring the productivity of captive populations of inbred and outbred Drosophila melanogaster. We found cold winter temperatures were most stressful and induced the greatest inbreeding depression. Furthermore, these data, collected under natural field conditions, conformed to the same predictive linear relationship seen in Drosophila laboratory studies, with inbreeding depression increasing by 0.17 lethal equivalents for every 10 per cent increase in stress level. Our results suggest that under natural conditions stress level is a primary determinant of the magnitude of inbreeding depression and should be considered when assessing extinction vulnerability in small populations.

  15. Proteomic characterization of inbreeding-related cold sensitivity in Drosophila melanogaster.

    Directory of Open Access Journals (Sweden)

    Cornelis J Vermeulen

    Full Text Available Inbreeding depression is a widespread phenomenon of central importance to agriculture, medicine, conservation biology and evolutionary biology. Although the population genetic principles of inbreeding depression are well understood, we know little about its functional genomic causes. To provide insight into the molecular interplay between intrinsic stress responses, inbreeding depression and temperature tolerance, we performed a proteomic characterization of a well-defined conditional inbreeding effect in a single line of Drosophila melanogaster, which suffers from extreme cold sensitivity and lethality. We identified 48 differentially expressed proteins in a conditional lethal line as compared to two control lines. These proteins were enriched for proteins involved in hexose metabolism, in particular pyruvate metabolism, and many were found to be associated with lipid particles. These processes can be linked to known cold tolerance mechanisms, such as the production of cryoprotectants, membrane remodeling and the build-up of energy reserves. We checked mRNA-expression of seven genes with large differential protein expression. Although protein expression poorly correlated with gene expression, we found a single gene (CG18067 that, after cold shock, was upregulated in the conditional lethal line both at the mRNA and protein level. Expression of CG18067 also increased in control flies after cold shock, and has previously been linked to cold exposure and chill coma recovery time. Many differentially expressed proteins in our study appear to be involved in cold tolerance in non-inbred individuals. This suggest the conditional inbreeding effect to be caused by misregulation of physiological cold tolerance mechanisms.

  16. Inbreeding avoidance influences the viability of reintroduced populations of African wild dogs (Lycaon pictus.

    Directory of Open Access Journals (Sweden)

    Penny A Becker

    Full Text Available The conservation of many fragmented and small populations of endangered African wild dogs (Lycaon pictus relies on understanding the natural processes affecting genetic diversity, demographics, and future viability. We used extensive behavioural, life-history, and genetic data from reintroduced African wild dogs in South Africa to (1 test for inbreeding avoidance via mate selection and (2 model the potential consequences of avoidance on population persistence. Results suggested that wild dogs avoided mating with kin. Inbreeding was rare in natal packs, after reproductive vacancies, and between sibling cohorts (observed on 0.8%, 12.5%, and 3.8% of occasions, respectively. Only one of the six (16.7% breeding pairs confirmed as third-order (or closer kin consisted of animals that were familiar with each other, while no other paired individuals had any prior association. Computer-simulated populations allowed to experience inbreeding had only a 1.6% probability of extinction within 100 years, whereas all populations avoiding incestuous matings became extinct due to the absence of unrelated mates. Populations that avoided mating with first-order relatives became extinct after 63 years compared with persistence of 37 and 19 years for those also prevented from second-order and third-order matings, respectively. Although stronger inbreeding avoidance maintains significantly more genetic variation, our results demonstrate the potentially severe demographic impacts of reduced numbers of suitable mates on the future viability of small, isolated wild dog populations. The rapid rate of population decline suggests that extinction may occur before inbreeding depression is observed.

  17. The joint regulation of genetic gain and inbreeding under mate selection.

    Science.gov (United States)

    Klieve, H M; Kinghorn, B P; Barwick, S A

    1994-01-12

    Stochastic simulation was used to evaluate a range of selection strategies with respect to both additive genetic response and inbreeding. Strategies involving selection on BLUP ebvs or individual phenotype, followed by random mating, were compared with mate selection strategies which used portfolio analysis to give joint consideration to genetic merit and inbreeding. An adapted Mean Of Total Absolute Deviations (MOTAD) method was used in a mate selection model to define optimal matings with regard to aggregate genetic merit and inbreeding for a base population h(2) of 0.2. Compared with random mating following selection on BLUP ebvs, inbreeding levels after 10 years of selection were able to be reduced under BLUP plus mate selection from ∼.23 to as little as .11. Additive genetic gain was either little compromised or increased. The results suggest that information linking expected levels of genetic merit and inbreeding can be used to find the preferred selection strategy. ZUSAMMENFASSUNG: Gemeinsame Kontrolle von Zuchtfortschritt und Inzucht bei Partnerselektion Es wurde stochastische Simulation zur Auswertung einer Reihe von Selektionsstrategien hinsichtlich Zuchtwertzuwachs und Inzucht verwendet. Strategien mit Selektion auf der Basis von BLUP ebvs oder individuellem Phänotyp mit nachfolgender Zufallspaarung wurden mit Partnerselektionsstrategien verglichen, die Portfolioanalyse zur gemeinsamen Beachtung von Zuchtwert und Inzucht verwendeten. Eine Methode adaptierter MITTELWERTE TOTALER ABSOLUTER ABWEICHUNGEN (MOTAD) Methode wurde beim Partnerselektionsmodell zur Definition optimaler Paarungen in Hinblick auf Gesamtzuchtwert und Inzucht bei einer Populationsheritabilität von 0,2 verwendet. Verglichen mit Zufallspaarung nach Selektion auf BLUP ebvs waren die Inzuchtgrade nach 10 Selektionsjahren von 0,23 auf 0,11 reduziert und additiver Zuchtfortschritt war dabei wenig beeinträchtigt oder nahm sogar zu. Die Ergebnisse weisen darauf hin, daß Information, die

  18. Inbreeding effects on the growth in stature among Telaga boys and girls of Kharagpur, West Bengal, India.

    Science.gov (United States)

    Das, Bidhan Kanti; Mukherjee, D P

    2007-03-01

    The present study is an attempt to understand the genetical effects of inbreeding on the process of growth. The inbred and non-inbred subjects were selected on the basis of extensive pedigrees of five generations in the Telaga, an endogamous population of Kharagpur, India. Preference was given to cousins belonging to the same kindreds while selecting control sample so that environmental variation was minimized. Altogether 633 boys and 614 girls of different inbreeding levels aged five to twenty years were measured for stature. Analysis has been done in different levels of inbreeding in each age and sex on mean annual increments and variances of increments. The results revealed that comparison of annual increment for each age between boys and girls with different degrees of inbreeding and application of the one-tailed t-test of significance does not provide any evidence of inbreeding effect on mean increment for stature studied in either sex. This might indicate the absence of marked dominant/recessive effects of genes determining annual increments in body size rather than the absence of genetical control of increments due to growth. Moreover, it is noteworthy that the variance of annual increment due to growth (which is estimated indirectly) consistently increases with increase of inbreeding level with only a few exceptions. The exceptions occur more often in girls than in boys, which can be explained by greater environmental stress and selection pressure and variation in X-linked inbreeding among girls. This would be worthwhile to verify in longitudinal growth data in future. Increased variances of annual increment with inbreeding, in the absence of change of mean increment on inbreeding, would indicate the influence of additive autosomal genes for the process of physical growth in children in either sex. A close scrutiny of the annual increments for the measurements in all the four levels of inbreeding in either sex fails to bring out any consistent trend of

  19. The effect of a low level of inbreeding on characters of linear evaluation of the exterior of holstein cows

    Directory of Open Access Journals (Sweden)

    Jiří Bezdíček

    2005-01-01

    Full Text Available The objective of the present study was to evaluate the effect of a relatively more frequent occurrence of lower coefficients of inbreeding in a population of Holstein cattle on the exterior characters. The exterior of inbred cows (on the level of Fx = 1.56 – 4.00% was compared with their outbreed contemporaries, i.e. half-sisters from the same father. Evaluations of the exterior of both inbred cows and contemporaries were conducted on the same day, 60-180 days after the first calving, in the same barn and using the valid mode of operation “Linear description and evaluation of the exterior of Holstein cattle”. The group consisted of 212 inbred cows and 521 contemporaries. This monitoring is part of a more extensive study dealing with the effect of low levels of Fx coefficients on the characters of milk performance. On that score, the evaluations primarily include characters that are associated with milk production.The group of inbred cows was compared with their contemporaries and the increased variability of all the evaluated characters (Vx was studied. The increased variability was particularly due to the wider variance of characters and/or due to the more frequent occurrence of the characters, in inbred animals including both biological extremes (maximum and minimum. Compared to the contemporaries the average values of exterior characters of inbred animals were lower. The most marked decrease in the values was detected for the fore udder attachment (0.28 points, i.e. 5.5 % and for the total evaluation of the legs (-0.80 points, i.e. a 1.04% decrease. Although the worsening of the exterior of inbred animals involved all the characters under study, compared to the outbreed contemporaries the differences on the studied level of Fx were not statistically significant.

  20. A major QTL affects temperature sensitive adult lethality and inbreeding depression in life span in Drosophila melanogaster.

    DEFF Research Database (Denmark)

    Vermeulen, Corneel J.; Bijlsma, R.; Loeschcke, Volker

    2008-01-01

    of inbreeding effects in specific traits, such as age-specific mortality and life span, provide a good starting point, as a limited set of genes is expected to be involved. Results Here we report on a QTL mapping study on inbreeding related and temperature sensitive lethality in male Drosophila melanogaster...... and the molecular properties of genes that give rise to or modulate its deleterious effects is lacking. These questions warrant the detailed study of genetic loci giving rise to inbreeding depression. However, the complex and polygenic nature of general inbreeding depression makes this a daunting task. Study...... simple, being due mainly to a single recessive QTL on the left arm of chromosome 2. This locus colocalised with a QTL that conditioned variation in female life span, acting as an overdominant locus for this trait. Male life span was additionally affected by variation at the X-chromosome. Conclusion...

  1. Fitness Costs Predict Inbreeding Aversion Irrespective of Self-Involvement: Support for Hypotheses Derived from Evolutionary Theory

    OpenAIRE

    Antfolk, Jan; Lieberman, Debra; Santtila, Pekka

    2012-01-01

    It is expected that in humans, the lowered fitness of inbred offspring has produced a sexual aversion between close relatives. Generally, the strength of this aversion depends on the degree of relatedness between two individuals, with closer relatives inciting greater aversion than more distant relatives. Individuals are also expected to oppose acts of inbreeding that do not include the self, as inbreeding between two individuals posits fitness costs not only to the individuals involved in th...

  2. Nature and magnitude of genetic variability, heterosis and inbreeding depression in Amaranthus

    Directory of Open Access Journals (Sweden)

    Pandey R.M.

    2007-01-01

    Full Text Available Combining ability, heterosis and inbreeding depression were estimated in grain amaranths for ten characters. Non-additive genetic variance was predominant for majority of characters in both F1 and F2 generations. The parent AG-21 was good general combiner for yield/plant also showed high GCA effects for panicles/plant and harvest index in both F1 and F2 generations. Seven characters, the best F2s on the basis of SCA involves one parent with high GCA effect and the other with poor or average GCA effects. The hybrids which exhibited highest heterosis also showed high inbreeding depression. Heterosis over better parent was highest for economic grain yield (145.047%, followed by panicles/plant (113.675%, panicle length (33.656% and grain weight/panicle (23.566%.

  3. How much gene flow is needed to avoid inbreeding depression in wild tiger populations?

    Science.gov (United States)

    Kenney, John; Allendorf, Fred W.; McDougal, Charles; Smith, James L. D.

    2014-01-01

    The number and size of tiger populations continue to decline owing to habitat loss, habitat fragmentation and poaching of tigers and their prey. As a result, tiger populations have become small and highly structured. Current populations have been isolated since the early 1970s or for approximately seven generations. The objective of this study is to explore how inbreeding may be affecting the persistence of remaining tiger populations and how dispersal, either natural or artificial, may reduce the potentially detrimental effect of inbreeding depression. We developed a tiger simulation model and used published levels of genetic load in mammals to simulate inbreeding depression. Following a 50 year period of population isolation, we introduced one to four dispersing male tigers per generation to explore how gene flow from nearby populations may reduce the negative impact of inbreeding depression. For the smallest populations, even four dispersing male tigers per generation did not increase population viability, and the likelihood of extinction is more than 90% within 30 years. Unless habitat connectivity is restored or animals are artificially introduced in the next 70 years, medium size wild populations are also likely to go extinct, with only four to five of the largest wild tiger populations likely to remain extant in this same period without intervention. To reduce the risk of local extinction, habitat connectivity must be pursued concurrently with efforts to increase population size (e.g. enhance habitat quality, increase habitat availability). It is critical that infrastructure development, dam construction and other similar projects are planned appropriately so that they do not erode the extent or quality of habitat for these populations so that they can truly serve as future source populations. PMID:24990671

  4. Changes in floral biology and inbreeding depression in native and invaded regions of Datura stramonium.

    Science.gov (United States)

    Jiménez-Lobato, V; Martínez-Borda, E; Núñez-Farfán, J; Valverde, P L; Cruz, L L; López-Velázquez, A; Santos-Gally, R; Arroyo, J

    2018-01-01

    Plant populations invading new environments might compromise their fitness contribution to the next generation, because of the lack of native specialist pollinators and/or potential mates. Thus, changes in plant mating system and traits linked to it are expected in populations colonising new environments where selection would favour selfing and floral traits that maximise reproductive output. To test this, we studied native (Mexico) and non-native (Spain) populations of the obligate sexual reproducing annual weed Datura stramonium. Flower size, herkogamy, total number of seeds per plant, number of visits by and type of pollinators, and inbreeding depression were assessed in native and non-native populations. Finally, we measured phenotypic selection on corolla size and herkogamy in each population. Flower size and herkogamy showed wide and similar variation in both ranges. However, the largest average flower size was found in one non-native population whereas the highest average positive herkogamy was detected in one native population. On average, flowers in the native range received more visits by pollinators. Hawkmoths were the main visitors in the native populations while only bees were observed visiting flowers in Spain's populations. Only in the native range was inbreeding depression detected. Selection to reduce herkogamy was found only in one native population. Absence of both inbreeding depression and selection on floral traits suggest a change in mating system of D. stramonium in a new range where generalist pollinators may be promoting high reproductive success. Selection against deleterious alleles might explain the reduction of inbreeding depression, promoting the evolution of selfing. © 2017 German Society for Plant Sciences and The Royal Botanical Society of the Netherlands.

  5. Adjustment of costly extra-group paternity according to inbreeding risk in a cooperative mammal.

    Science.gov (United States)

    Nichols, Hazel J; Cant, Michael A; Sanderson, Jennifer L

    2015-01-01

    Females of many animal species seek mating opportunities with multiple males, despite being able to obtain sufficient sperm to father their offspring from a single male. In animals that live in stable social groups, females often choose to mate outside their group resulting in extra-group paternity (EGP). One reason proposed to explain female choice for extra-group males is to obtain compatible genes, for example, in order to avoid inbreeding depression in offspring. The benefits of such extra-group paternities could be substantial if they result in fitter, outbred offspring. However, avoiding inbreeding in this way could be costly for females, for example, through retaliation by cuckolded males or through receiving aggression while prospecting for extra-group mating opportunities. We investigate the costs and benefits of EGP in the banded mongoose Mungos mungo , a cooperatively breeding mammal in which within-group mates are sometimes close relatives. We find that pups born to females that mate with extra-group males are more genetically heterozygous are heavier and are more likely to survive to independence than pups born to females that mate within their group. However, extra-group matings also involve substantial costs as they occur during violent encounters that sometimes result in injury and death. This appears to lead femalebanded mongooses to adaptively adjust EGP levels according to the current risk of inbreeding associated with mating within the group. For group-living animals, the costs of intergroup interactions may help to explain variation in both inbreeding rates and EGP within and between species.

  6. Inbreeding and Genetic Diversity in Three Imported Swine Breeds in China Using Pedigree Data

    Directory of Open Access Journals (Sweden)

    G. Q. Tang

    2013-06-01

    Full Text Available The accumulation of inbreeding and the loss of genetic diversity is a potential problem in the modern swine breeds in China. Therefore, the purpose of this study was to analyze the pedigrees of Chinese Duroc (CD, Landrace (CL and Yorkshire (CY swine to estimate the past and current rates of inbreeding, and to identify the main causes of genetic diversity loss. Pedigree files from CD, CL and CY containing, 4529, 16,776 and 22,600 records, respectively, were analyzed. Pedigree completeness indexes of the three breeds, accounting for one generation back, were 83.72, 93.93 and 93.59%, respectively. The estimated average annual inbreeding rates for CD, CL and CY in recent three years were 0.21, 0.19 and 0.13%, respectively. The estimated average percentage of genetic diversity loss within each breed in recent three years was about 8.92, 2.19, and 3.36%, respectively. The average relative proportion of genetic diversity loss due to unequal contributions of founders in CD, CL and CY was 69.09, 57.95 and 60.57%, and due to random genetic drift was 30.91, 42.05 and 39.43%, respectively. The estimated current effective population size for CD, CL and CY was 76, 117 and 202, respectively. Therefore, CD has been found to have lost considerable genetic diversity, demanding priority for optimizing the selection and mating to control future coancestry and inbreeding. Unequal contribution of founders was a major cause of genetic diversity loss in Chinese swine breeds and random genetic drift also showed substantial impact on the loss of diversity.

  7. An experimental test of the Westermarck effect: sex differences in inbreeding avoidance

    OpenAIRE

    Urszula M. Marcinkowska; Fhionna R. Moore; Markus J. Rantala

    2013-01-01

    In order to avoid inbreeding, humans and other animals develop a strong sexual aversion to individuals with whom they have lived closely in infancy and early childhood (usually biological siblings), a phenomenon called the "Westermarck effect" or negative sexual imprinting. The mechanisms underlying this phenomenon, however, remain unclear. For example, it is not known whether negative imprinting is based only on actual sexual aversion to brothers and sisters or also on generalizing the trait...

  8. How much gene flow is needed to avoid inbreeding depression in wild tiger populations?

    Science.gov (United States)

    Kenney, John; Allendorf, Fred W; McDougal, Charles; Smith, James L D

    2014-08-22

    The number and size of tiger populations continue to decline owing to habitat loss, habitat fragmentation and poaching of tigers and their prey. As a result, tiger populations have become small and highly structured. Current populations have been isolated since the early 1970s or for approximately seven generations. The objective of this study is to explore how inbreeding may be affecting the persistence of remaining tiger populations and how dispersal, either natural or artificial, may reduce the potentially detrimental effect of inbreeding depression. We developed a tiger simulation model and used published levels of genetic load in mammals to simulate inbreeding depression. Following a 50 year period of population isolation, we introduced one to four dispersing male tigers per generation to explore how gene flow from nearby populations may reduce the negative impact of inbreeding depression. For the smallest populations, even four dispersing male tigers per generation did not increase population viability, and the likelihood of extinction is more than 90% within 30 years. Unless habitat connectivity is restored or animals are artificially introduced in the next 70 years, medium size wild populations are also likely to go extinct, with only four to five of the largest wild tiger populations likely to remain extant in this same period without intervention. To reduce the risk of local extinction, habitat connectivity must be pursued concurrently with efforts to increase population size (e.g. enhance habitat quality, increase habitat availability). It is critical that infrastructure development, dam construction and other similar projects are planned appropriately so that they do not erode the extent or quality of habitat for these populations so that they can truly serve as future source populations. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  9. Evidence for inbreeding depression in a species with limited opportunity for maternal effects.

    Science.gov (United States)

    Vega-Trejo, Regina; Head, Megan L; Jennions, Michael D

    2015-04-01

    It is often assumed that mating with close relatives reduces offspring fitness. In such cases, reduced offspring fitness may arise from inbreeding depression (i.e., genetic effects of elevated homozygosity) or from post-mating maternal investment. This can be due to a reduction in female investment after mating with genetically incompatible males ("differential allocation") or compensation for incompatibility ("reproductive compensation"). Here, we looked at the effects of mating with relatives on offspring fitness in mosquitofish, Gambusia holbrooki. In this species, females are assumed to be nonplacental and to allocate resources to eggs before fertilization, limiting differential allocation. We looked at the effects of mating with a brother or with an unrelated male on brood size, offspring size, gestation period, and early offspring growth. Mating with a relative reduced the number of offspring at birth, but there was no difference in the likelihood of breeding, gestation time, nor in the size or growth of these offspring. We suggest that due to limited potential for maternal effects to influence these traits that any reduction in offspring fitness, or lack thereof, can be explained by inbreeding depression rather than by maternal effects. We highlight the importance of considering the potential role of maternal effects when studying inbreeding depression and encourage further studies in other Poeciliid species with different degrees of placentation to test whether maternal effects mask or amplify any genetic effects of mating with relatives.

  10. The ghost of outcrossing past in downy brome, an inbreeding annual grass.

    Science.gov (United States)

    Meyer, Susan E; Ghimire, Sudeep; Decker, Samuel; Merrill, Keith R; Coleman, Craig E

    2013-01-01

    We investigated the frequency of outcrossing in downy brome (Bromus tectorum L.), a cleistogamous weedy annual grass, in both common garden and wild populations, using microsatellite and single nucleotide polymorphic (SNP) markers. In the common garden study, 25 lines with strongly contrasting genotypes were planted in close proximity. We fingerprinted 10 seed progeny from 8 individuals of each line and detected 15 first-generation heterozygotes for a t-value (corrected for cryptic crosses) of 0.0082. Different genotypes were significantly overrepresented as maternal versus paternal parents of heterozygotes, suggesting gender-function-dependent genetic control of outcrossing rates. In 4 wild populations (>300 individuals each), expected heterozygosity ranged from 0.149 to 0.336, whereas t-values ranged from 0.0027 to 0.0133, indicating high levels of both genetic diversity and inbreeding. Up to a third of the individuals in each population belonged to groups with identical or nearly identical SNP genotypes, whereas many of the remaining individuals were members of loose clusters of apparently related plants that probably represent descendants from past outcrossing events. Strict inbreeding in some lineages within a population with occasional outcrossing in others may be related to positive selection on adaptive syndromes associated with specific inbreeding lineages, or possibly to among-lineage differences in genetic regulation of outcrossing.

  11. Severe inbreeding and small effective number of breeders in a formerly abundant marine fish.

    Directory of Open Access Journals (Sweden)

    Shannon J O'Leary

    Full Text Available In contrast to freshwater fish it is presumed that marine fish are unlikely to spawn with close relatives due to the dilution effect of large breeding populations and their propensity for movement and reproductive mixing. Inbreeding is therefore not typically a focal concern of marine fish management. We measured the effective number of breeders in 6 New York estuaries for winter flounder (Pseudopleuronectes americanus, a formerly abundant fish, using 11 microsatellite markers (6-56 alleles per locus. The effective number of breeders for 1-2 years was remarkably small, with point estimates ranging from 65-289 individuals. Excess homozygosity was detected at 10 loci in all bays (FIS = 0.169-0.283 and individuals exhibited high average internal relatedness (IR; mean = 0.226. These both indicate that inbreeding is very common in all bays, after testing for and ruling out alternative explanations such as technical and sampling artifacts. This study demonstrates that even historically common marine fish can be prone to inbreeding, a factor that should be considered in fisheries management and conservation plans.

  12. Subsocial Cockroaches Nauphoeta cinerea Mate Indiscriminately with Kin Despite High Costs of Inbreeding

    Science.gov (United States)

    Bouchebti, Sofia; Durier, Virginie; Pasquaretta, Cristian; Rivault, Colette; Lihoreau, Mathieu

    2016-01-01

    Many animals have evolved strategies to reduce risks of inbreeding and its deleterious effects on the progeny. In social arthropods, such as the eusocial ants and bees, inbreeding avoidance is typically achieved by the dispersal of breeders from their native colony. However studies in presocial insects suggest that kin discrimination during mate choice may be a more common mechanism in socially simpler species with no reproductive division of labour. Here we examined this possibility in the subsocial cockroach Nauphoeta cinerea, a model species for research in sexual selection, where males establish dominance hierarchies to access females and control breeding territories. When given a binary choice between a sibling male and a non-sibling male that had the opportunity to establish a hierarchy prior to the tests, females mated preferentially with the dominant male, irrespective of kinship or body size. Despite the lack of kin discrimination during mate choice, inbred-mated females incurred significant fitness costs, producing 20% less offspring than outbred-mated females. We discuss how the social mating system of this territorial cockroach may naturally limit the probability of siblings to encounter and reproduce, without the need for evolving active inbreeding avoidance mechanisms, such as kin recognition. PMID:27655156

  13. Inbreeding affects sexual signalling in males but not females of Tenebrio molitor.

    Science.gov (United States)

    Pölkki, Mari; Krams, Indrikis; Kangassalo, Katariina; Rantala, Markus J

    2012-06-23

    In many species of animals, individuals advertise their quality with sexual signals to obtain mates. Chemical signals such as volatile pheromones are species specific, and their primary purpose is to influence mate choice by carrying information about the phenotypic and genetic quality of the sender. The deleterious effects of consanguineous mating on individual quality are generally known, whereas the effect of inbreeding on sexual signalling is poorly understood. Here, we tested whether inbreeding reduces the attractiveness of sexual signalling in the mealworm beetle, Tenebrio molitor, by testing the preferences for odours of inbred and outbred (control) individuals of the opposite sex. Females were more attracted to the odours produced by outbred males than the odours produced by inbred males, suggesting that inbreeding reduces the attractiveness of male sexual signalling. However, we did not find any difference between the attractiveness of inbred and outbred female odours, which may indicate that the quality of females is either irrelevant for T. molitor males or quality is not revealed through female odours.

  14. Ethnohistorical evidence for inbreeding among the pre-Hispanic Mixtec royal caste.

    Science.gov (United States)

    Christensen, A F

    1998-06-01

    Pre-Columbian Mixtec social organization was distinguished by the tight endogamy of the ruling class, which included many consanguineous marriages. It was also characterized by a vigorous historical and genealogical tradition. The historical documents, or codices, provide materials for the calculation of the levels of inbreeding present before the Spanish Conquest. A genealogical analysis of inbreeding was performed on the combined pedigree, which spanned the tenth through sixteenth centuries, of all individuals connected by ancestry, descent, or marriage with Lord 8 Deer Jaguar Claw of Tilantongo (A.D. 1063-1115). Sixty of the 217 couples (27.65%) were consanguineous. When only couples of wholly known grandparentage were considered (N = 39), F = 0.1051. The mean F of all couples, even those where one spouse was of unknown parentage, was 0.0243. Over the 550 years of the pedigree the maximum F in any 52-year period was 0.1324. This level of inbreeding is sufficient to produce noticeable effects on population structure and affinities over time.

  15. Subsocial Cockroaches Nauphoeta cinerea Mate Indiscriminately with Kin Despite High Costs of Inbreeding.

    Directory of Open Access Journals (Sweden)

    Sofia Bouchebti

    Full Text Available Many animals have evolved strategies to reduce risks of inbreeding and its deleterious effects on the progeny. In social arthropods, such as the eusocial ants and bees, inbreeding avoidance is typically achieved by the dispersal of breeders from their native colony. However studies in presocial insects suggest that kin discrimination during mate choice may be a more common mechanism in socially simpler species with no reproductive division of labour. Here we examined this possibility in the subsocial cockroach Nauphoeta cinerea, a model species for research in sexual selection, where males establish dominance hierarchies to access females and control breeding territories. When given a binary choice between a sibling male and a non-sibling male that had the opportunity to establish a hierarchy prior to the tests, females mated preferentially with the dominant male, irrespective of kinship or body size. Despite the lack of kin discrimination during mate choice, inbred-mated females incurred significant fitness costs, producing 20% less offspring than outbred-mated females. We discuss how the social mating system of this territorial cockroach may naturally limit the probability of siblings to encounter and reproduce, without the need for evolving active inbreeding avoidance mechanisms, such as kin recognition.

  16. Mutual mate choice: when it pays both sexes to avoid inbreeding.

    Directory of Open Access Journals (Sweden)

    Mathieu Lihoreau

    Full Text Available Theoretical models of sexual selection predict that both males and females of many species should benefit by selecting their mating partners. However, empirical evidence testing and validating this prediction is scarce. In particular, whereas inbreeding avoidance is expected to induce sexual conflicts, in some cases both partners could benefit by acting in concert and exerting mutual mate choice for non-assortative pairings. We tested this prediction with the gregarious cockroach Blattella germanica (L.. We demonstrated that males and females base their mate choice on different criteria and that choice occurs at different steps during the mating sequence. Males assess their relatedness to females through antennal contacts before deciding to court preferentially non-siblings. Conversely, females biased their choice towards the most vigorously courting males that happened to be non-siblings. This study is the first to demonstrate mutual mate choice leading to close inbreeding avoidance. The fact that outbred pairs were more fertile than inbred pairs strongly supports the adaptive value of this mating system, which includes no "best phenotype" as the quality of two mating partners is primarily linked to their relatedness. We discuss the implications of our results in the light of inbreeding conflict models.

  17. Founder-specific inbreeding depression affects racing performance in Thoroughbred horses.

    Science.gov (United States)

    Todd, Evelyn T; Ho, Simon Y W; Thomson, Peter C; Ang, Rachel A; Velie, Brandon D; Hamilton, Natasha A

    2018-04-18

    The Thoroughbred horse has played an important role in both sporting and economic aspects of society since the establishment of the breed in the 1700s. The extensive pedigree and phenotypic information available for the Thoroughbred horse population provides a unique opportunity to examine the effects of 300 years of selective breeding on genetic load. By analysing the relationship between inbreeding and racing performance of 135,572 individuals, we found that selective breeding has not efficiently alleviated the Australian Thoroughbred population of its genetic load. However, we found evidence for purging in the population that might have improved racing performance over time. Over 80% of inbreeding in the contemporary population is accounted for by a small number of ancestors from the foundation of the breed. Inbreeding to these ancestors has variable effects on fitness, demonstrating that an understanding of the distribution of genetic load is important in improving the phenotypic value of a population in the future. Our findings hold value not only for Thoroughbred and other domestic breeds, but also for small and endangered populations where such comprehensive information is not available.

  18. Maintenance of genetic variation in human personality: testing evolutionary models by estimating heritability due to common causal variants and investigating the effect of distant inbreeding.

    Science.gov (United States)

    Verweij, Karin J H; Yang, Jian; Lahti, Jari; Veijola, Juha; Hintsanen, Mirka; Pulkki-Råback, Laura; Heinonen, Kati; Pouta, Anneli; Pesonen, Anu-Katriina; Widen, Elisabeth; Taanila, Anja; Isohanni, Matti; Miettunen, Jouko; Palotie, Aarno; Penke, Lars; Service, Susan K; Heath, Andrew C; Montgomery, Grant W; Raitakari, Olli; Kähönen, Mika; Viikari, Jorma; Räikkönen, Katri; Eriksson, Johan G; Keltikangas-Järvinen, Liisa; Lehtimäki, Terho; Martin, Nicholas G; Järvelin, Marjo-Riitta; Visscher, Peter M; Keller, Matthew C; Zietsch, Brendan P

    2012-10-01

    Personality traits are basic dimensions of behavioral variation, and twin, family, and adoption studies show that around 30% of the between-individual variation is due to genetic variation. There is rapidly growing interest in understanding the evolutionary basis of this genetic variation. Several evolutionary mechanisms could explain how genetic variation is maintained in traits, and each of these makes predictions in terms of the relative contribution of rare and common genetic variants to personality variation, the magnitude of nonadditive genetic influences, and whether personality is affected by inbreeding. Using genome-wide single nucleotide polymorphism (SNP) data from > 8000 individuals, we estimated that little variation in the Cloninger personality dimensions (7.2% on average) is due to the combined effect of common, additive genetic variants across the genome, suggesting that most heritable variation in personality is due to rare variant effects and/or a combination of dominance and epistasis. Furthermore, higher levels of inbreeding were associated with less socially desirable personality trait levels in three of the four personality dimensions. These findings are consistent with genetic variation in personality traits having been maintained by mutation-selection balance. © 2012 The Author(s). Evolution© 2012 The Society for the Study of Evolution.

  19. Higher harmonic flow coefficients of identified hadrons in Pb-Pb collisions at s N N = 2.76 $$ \\sqrt{s_{\\mathrm{NN}}}=2.76 $$ TeV

    NARCIS (Netherlands)

    Adam, J.; Adamová, D.; Aggarwal, M. M.; Aglieri Rinella, G.; Agnello, M.; Agrawal, N.; Ahammed, Z.; Ahmad, S.; Ahn, S. U.; Aiola, S.; Akindinov, A.; Alam, S. N.; Albuquerque, D. S. D.; Aleksandrov, D.; Alessandro, B.; Alexandre, D.; Alfaro Molina, R.; Alici, A.; Alkin, A.; Alme, J.; Alt, T.; Altinpinar, S.; Altsybeev, I.; Alves Garcia Prado, C.; An, M.; Andrei, C.; Andrews, H. A.; Andronic, A.; Anguelov, V.; Antičić, T.; Antinori, F.; Antonioli, P.; Aphecetche, L.; Appelshäuser, H.; Arcelli, S.; Arnaldi, R.; Arnold, O. W.; Arsene, I. C.; Arslandok, M.; Audurier, B.; Augustinus, A.; Averbeck, R.; Azmi, M. D.; Badalà, A.; Baek, Y. W.; Bagnasco, S.; Bailhache, R.; Bala, R.; Balasubramanian, S.; Baldisseri, A.; Baral, R. C.; Barbano, A. M.; Barbera, R.; Barile, F.; Barnaföldi, G. G.; Barnby, L. S.; Barret, V.; Bartalini, P.; Barth, K.; Bartke, J.; Bartsch, E.; Basile, M.; Bastid, N.; Basu, S.; Bathen, B.; Batigne, G.; Batista Camejo, A.; Batyunya, B.; Batzing, P. C.; Bearden, I. G.; Beck, H.; Bedda, C.; Behera, N. K.; Belikov, I.; Bellini, F.; Bello Martinez, H.; Bellwied, R.; Belmont, R.; Belmont-moreno, E.; Beltran, L. G. E.; Belyaev, V.; Bencedi, G.; Beole, S.; Berceanu, I.; Bercuci, A.; Berdnikov, Y.; Berenyi, D.; Bertens, R. A.; Berzano, D.; Betev, L.; Bhasin, A.; Bhat, I. R.; Bhati, A. K.; Bhattacharjee, B.; Bhom, J.; Bianchi, L.; Bianchi, N.; Bianchin, C.; Bielčík, J.; Bielčíková, J.; Bilandzic, A.; Biro, G.; Biswas, R.; Biswas, S.; Bjelogrlic, S.; Blair, J. T.; Blau, D.; Blume, C.; Bock, F.; Bogdanov, A.; Bøggild, H.; Boldizsár, L.; Bombara, M.; Bonora, M.; Book, J.; Borel, H.; Borissov, A.; Borri, M.; Bossú, F.; Botta, E.; Bourjau, C.; Braun-munzinger, P.; Bregant, M.; Breitner, T.; Broker, T. A.; Browning, T. A.; Broz, M.; Brucken, E. J.; Bruna, E.; Bruno, G. E.; Budnikov, D.; Buesching, H.; Bufalino, S.; Buncic, P.; Busch, O.; Buthelezi, Z.; Butt, J. B.; Buxton, J. T.; Cabala, J.; Caffarri, D.; Cai, X.; Caines, H.; Calero Diaz, L.; Caliva, A.; Calvo Villar, E.; Camerini, P.; Carena, F.; Carena, W.; Carnesecchi, F.; Castillo Castellanos, J.; Castro, A. J.; Casula, E. A. R.; Ceballos Sanchez, C.; Cepila, J.; Cerello, P.; Cerkala, J.; Chang, B.; Chapeland, S.; Chartier, M.; Charvet, J. L.; Chattopadhyay, S.; Chattopadhyay, S.; Chauvin, A.; Chelnokov, V.; Cherney, M.; Cheshkov, C.; Cheynis, B.; Chibante Barroso, V.; Chinellato, D. D.; Cho, S.; Chochula, P.; Choi, K.; Chojnacki, M.; Choudhury, S.; Christakoglou, P.; Christensen, C. H.; Christiansen, P.; Chujo, T.; Chung, S. U.; Cicalo, C.; Cifarelli, L.; Cindolo, F.; Cleymans, J.; Colamaria, F.; Colella, D.; Collu, A.; Colocci, M.; Conesa Balbastre, G.; Conesa Del Valle, Z.; Connors, M. E.; Contreras, J. G.; Cormier, T. M.; Corrales Morales, Y.; Cortés Maldonado, I.; Cortese, P.; Cosentino, M. R.; Costa, F.; Crkovska, J.; Crochet, P.; Cruz Albino, R.; Cuautle, E.; Cunqueiro, L.; Dahms, T.; Dainese, A.; Danisch, M. C.; Danu, A.; Das, D.; Das, I.; Das, S.; Dash, A.; Dash, S.; De, S.; De Caro, A.; De Cataldo, G.; De Conti, C.; De Cuveland, J.; De Falco, A.; De Gruttola, D.; De Marco, N.; De Pasquale, S.; De Souza, R. D.; Deisting, A.; Deloff, A.; Dénes, E.; Deplano, C.; Dhankher, P.; Di Bari, D.; Di Mauro, A.; Di Nezza, P.; Di Ruzza, B.; Diaz Corchero, M. A.; Dietel, T.; Dillenseger, P.; Divià, R.; Djuvsland, Ø.; Dobrin, A.; Domenicis Gimenez, D.; Dönigus, B.; Dordic, O.; Drozhzhova, T.; Dubey, A. K.; Dubla, A.; Ducroux, L.; Dupieux, P.; Ehlers, R. J.; Elia, D.; Endress, E.; Engel, H.; Epple, E.; Erazmus, B.; Erdemir, I.; Erhardt, F.; Espagnon, B.; Estienne, M.; Esumi, S.; Eulisse, G.; Eum, J.; Evans, D.; Evdokimov, S.; Eyyubova, G.; Fabbietti, L.; Fabris, D.; Faivre, J.; Fantoni, A.; Fasel, M.; Feldkamp, L.; Feliciello, A.; Feofilov, G.; Ferencei, J.; Fernández Téllez, A.; Ferreiro, E. G.; Ferretti, A.; Festanti, A.; Feuillard, V. J. G.; Figiel, J.; Figueredo, M. A. S.; Filchagin, S.; Finogeev, D.; Fionda, F. M.; Fiore, E. M.; Floris, M.; Foertsch, S.; Foka, P.; Fokin, S.; Fragiacomo, E.; Francescon, A.; Francisco, A.; Frankenfeld, U.; Fronze, G. G.; Fuchs, U.; Furget, C.; Furs, A.; Fusco Girard, M.; Gaardhøje, J. J.; Gagliardi, M.; Gago, A. M.; Gajdosova, K.; Gallio, M.; Galvan, C. D.; Gangadharan, D. R.; Ganoti, P.; Gao, C.; Garabatos, C.; Garcia-solis, E.; Garg, K.; Gargiulo, C.; Gasik, P.; Gauger, E. F.; Germain, M.; Gheata, M.; Ghosh, P.; Ghosh, S. K.; Gianotti, P.; Giubellino, P.; Giubilato, P.; Gladysz-dziadus, E.; Glässel, P.; Goméz Coral, D. M.; Gomez Ramirez, A.; Gonzalez, A. S.; Gonzalez, V.; González-zamora, P.; Gorbunov, S.; Görlich, L.; Gotovac, S.; Grabski, V.; Grachov, O. A.; Graczykowski, L. K.; Graham, K. L.; Grelli, A.; Grigoras, A.; Grigoras, C.; Grigoriev, V.; Grigoryan, A.; Grigoryan, S.; Grinyov, B.; Grion, N.; Gronefeld, J. M.; Grosse-oetringhaus, J. F.; Grosso, R.; Gruber, L.; Guber, F.; Guernane, R.; Guerzoni, B.; Gulbrandsen, K.; Gunji, T.; Gupta, A.; Gupta, R.; Guzman, I. B.; Haake, R.; Hadjidakis, C.; Haiduc, M.; Hamagaki, H.; Hamar, G.; Hamon, J. C.; Harris, J. W.; Harton, A.; Hatzifotiadou, D.; Hayashi, S.; Heckel, S. T.; Hellbär, E.; Helstrup, H.; Herghelegiu, A.; Herrera Corral, G.; Herrmann, F.; Hess, B. A.; Hetland, K. F.; Hillemanns, H.; Hippolyte, B.; Horak, D.; Hosokawa, R.; Hristov, P.; Hughes, C.; Humanic, T. J.; Hussain, N.; Hussain, T.; Hutter, D.; Hwang, D. S.; Ilkaev, R.; Inaba, M.; Incani, E.; Ippolitov, M.; Irfan, M.; Isakov, V.; Ivanov, M.; Ivanov, V.; Izucheev, V.; Jacak, B.; Jacazio, N.; Jacobs, P. M.; Jadhav, M. B.; Jadlovska, S.; Jadlovsky, J.; Jahnke, C.; Jakubowska, M. J.; Janik, M. A.; Jayarathna, P. H. S. Y.; Jena, C.; Jena, S.; Jimenez Bustamante, R. T.; Jones, P. G.; Jusko, A.; Kalinak, P.; Kalweit, A.; Kang, J. H.; Kaplin, V.; Kar, S.; Karasu Uysal, A.; Karavichev, O.; Karavicheva, T.; Karayan, L.; Karpechev, E.; Kebschull, U.; Keidel, R.; Keijdener, D. L. D.; Keil, M.; Mohisin Khan, M.; Khan, P.; Khan, S. A.; Khanzadeev, A.; Kharlov, Y.; Khatun, A.; Kileng, B.; Kim, D. W.; Kim, D. J.; Kim, D.; Kim, H.; Kim, J. S.; Kim, J.; Kim, M.; Kim, S.; Kim, T.; Kirsch, S.; Kisel, I.; Kiselev, S.; Kisiel, A.; Kiss, G.; Klay, J. L.; Klein, C.; Klein, J.; Klein-bösing, C.; Klewin, S.; Kluge, A.; Knichel, M. L.; Knospe, A. G.; Kobdaj, C.; Kofarago, M.; Kollegger, T.; Kolojvari, A.; Kondratiev, V.; Kondratyeva, N.; Kondratyuk, E.; Konevskikh, A.; Kopcik, M.; Kour, M.; Kouzinopoulos, C.; Kovalenko, O.; Kovalenko, V.; Kowalski, M.; Koyithatta Meethaleveedu, G.; Králik, I.; Kravčáková, A.; Krivda, M.; Krizek, F.; Kryshen, E.; Krzewicki, M.; Kubera, A. M.; Kučera, V.; Kuhn, C.; Kuijer, P. G.; Kumar, A.; Kumar, J.; Kumar, L.; Kumar, S.; Kurashvili, P.; Kurepin, A.; Kurepin, A. B.; Kuryakin, A.; Kweon, M. J.; Kwon, Y.; La Pointe, S. L.; La Rocca, P.; Ladron De Guevara, P.; Lagana Fernandes, C.; Lakomov, I.; Langoy, R.; Lapidus, K.; Lara, C.; Lardeux, A.; Lattuca, A.; Laudi, E.; Lea, R.; Leardini, L.; Lee, S.; Lehas, F.; Lehner, S.; Lemmon, R. C.; Lenti, V.; Leogrande, E.; León Monzón, I.; León Vargas, H.; Leoncino, M.; Lévai, P.; Li, S.; Li, X.; Lien, J.; Lietava, R.; Lindal, S.; Lindenstruth, V.; Lippmann, C.; Lisa, M. A.; Ljunggren, H. M.; Lodato, D. F.; Loenne, P. I.; Loginov, V.; Loizides, C.; Lopez, X.; López Torres, E.; Lowe, A.; Luettig, P.; Lunardon, M.; Luparello, G.; Lupi, M.; Lutz, T. H.; Maevskaya, A.; Mager, M.; Mahajan, S.; Mahmood, S. M.; Maire, A.; Majka, R. D.; Malaev, M.; Maldonado Cervantes, I.; Malinina, L.; Mal’kevich, D.; Malzacher, P.; Mamonov, A.; Manko, V.; Manso, F.; Manzari, V.; Mao, Y.; Marchisone, M.; Mareš, J.; Margagliotti, G. V.; Margotti, A.; Margutti, J.; Marín, A.; Markert, C.; Marquard, M.; Martin, N. A.; Martinengo, P.; Martínez, M. I.; Martínez García, G.; Martinez Pedreira, M.; Mas, A.; Masciocchi, S.; Masera, M.; Masoni, A.; Mastroserio, A.; Matyja, A.; Mayer, C.; Mazer, J.; Mazzilli, M.; Mazzoni, M. A.; Meddi, F.; Melikyan, Y.; Menchaca-rocha, A.; Meninno, E.; Mercado Pérez, J.; Meres, M.; Mhlanga, S.; Miake, Y.; Mieskolainen, M. M.; Mikhaylov, K.; Milano, L.; Milosevic, J.; Mischke, A.; Mishra, A. N.; Mishra, T.; Miskowiec, D.; Mitra, J.; Mitu, C. M.; Mohammadi, N.; Mohanty, B.; Molnar, L.; Montaño Zetina, L.; Montes, E.; Moreira De Godoy, D. A.; Moreno, L. A. P.; Moretto, S.; Morreale, A.; Morsch, A.; Muccifora, V.; Mudnic, E.; Mühlheim, D.; Muhuri, S.; Mukherjee, M.; Mulligan, J. D.; Munhoz, M. G.; Münning, K.; Munzer, R. H.; Murakami, H.; Murray, S.; Musa, L.; Musinsky, J.; Naik, B.; Nair, R.; Nandi, B. K.; Nania, R.; Nappi, E.; Naru, M. U.; Natal Da Luz, H.; Nattrass, C.; Navarro, S. R.; Nayak, K.; Nayak, R.; Nayak, T. K.; Nazarenko, S.; Nedosekin, A.; Negrao De Oliveira, R. A.; Nellen, L.; Ng, F.; Nicassio, M.; Niculescu, M.; Niedziela, J.; Nielsen, B. S.; Nikolaev, S.; Nikulin, S.; Nikulin, V.; Noferini, F.; Nomokonov, P.; Nooren, G.; Noris, J. C. C.; Norman, J.; Nyanin, A.; Nystrand, J.; Oeschler, H.; Oh, S.; Oh, S. K.; Ohlson, A.; Okatan, A.; Okubo, T.; Oleniacz, J.; Oliveira Da Silva, A. C.; Oliver, M. H.; Onderwaater, J.; Oppedisano, C.; Orava, R.; Oravec, M.; Ortiz Velasquez, A.; Oskarsson, A.; Otwinowski, J.; Oyama, K.; Ozdemir, M.; Pachmayer, Y.; Pagano, D.; Pagano, P.; Paić, G.; Pal, S. K.; Palni, P.; Pan, J.; Pandey, A. K.; Papikyan, V.; Pappalardo, G. S.; Pareek, P.; Park, W. J.; Parmar, S.; Passfeld, A.; Paticchio, V.; Patra, R. N.; Paul, B.; Pei, H.; Peitzmann, T.; Peng, X.; Pereira Da Costa, H.; Peresunko, D.; Perez Lezama, E.; Peskov, V.; Pestov, Y.; Petráček, V.; Petrov, V.; Petrovici, M.; Petta, C.; Piano, S.; Pikna, M.; Pillot, P.; Pimentel, L. O. D. L.; Pinazza, O.; Pinsky, L.; Piyarathna, D. B.; Ploskon, M.; Planinic, M.; Pluta, J.; Pochybova, S.; Podesta-lerma, P. L. M.; Poghosyan, M. G.; Polichtchouk, B.; Poljak, N.; Poonsawat, W.; Pop, A.; Poppenborg, H.; Porteboeuf-houssais, S.; Porter, J.; Pospisil, J.; Prasad, S. K.; Preghenella, R.; Prino, F.; Pruneau, C. A.; Pshenichnov, I.; Puccio, M.; Puddu, G.; Pujahari, P.; Punin, V.; Putschke, J.; Qvigstad, H.; Rachevski, A.; Raha, S.; Rajput, S.; Rak, J.; Rakotozafindrabe, A.; Ramello, L.; Rami, F.; Raniwala, R.; Raniwala, S.; Räsänen, S. S.; Rascanu, B. T.; Rathee, D.; Ravasenga, I.; Read, K. F.; Redlich, K.; Reed, R. J.; Rehman, A.; Reichelt, P.; Reidt, F.; Ren, X.; Renfordt, R.; Reolon, A. R.; Reshetin, A.; Reygers, K.; Riabov, V.; Ricci, R. A.; Richert, T.; Richter, M.; Riedler, P.; Riegler, W.; Riggi, F.; Ristea, C.; Rodríguez Cahuantzi, M.; Rodriguez Manso, A.; Røed, K.; Rogochaya, E.; Rohr, D.; Röhrich, D.; Ronchetti, F.; Ronflette, L.; Rosnet, P.; Rossi, A.; Roukoutakis, F.; Roy, A.; Roy, C.; Roy, P.; Rubio Montero, A. J.; Rui, R.; Russo, R.; Ryabinkin, E.; Ryabov, Y.; Rybicki, A.; Saarinen, S.; Sadhu, S.; Sadovsky, S.; Šafařík, K.; Sahlmuller, B.; Sahoo, P.; Sahoo, R.; Sahoo, S.; Sahu, P. K.; Saini, J.; Sakai, S.; Saleh, M. A.; Salzwedel, J.; Sambyal, S.; Samsonov, V.; Šándor, L.; Sandoval, A.; Sano, M.; Sarkar, D.; Sarkar, N.; Sarma, P.; Scapparone, E.; Scarlassara, F.; Schiaua, C.; Schicker, R.; Schmidt, C.; Schmidt, H. R.; Schmidt, M.; Schuchmann, S.; Schukraft, J.; Schutz, Y.; Schwarz, K.; Schweda, K.; Scioli, G.; Scomparin, E.; Scott, R.; Šefčík, M.; Seger, J. E.; Sekiguchi, Y.; Sekihata, D.; Selyuzhenkov, I.; Senosi, K.; Senyukov, S.; Serradilla, E.; Sevcenco, A.; Shabanov, A.; Shabetai, A.; Shadura, O.; Shahoyan, R.; Shangaraev, A.; Sharma, A.; Sharma, M.; Sharma, M.; Sharma, N.; Sheikh, A. I.; Shigaki, K.; Shou, Q.; Shtejer, K.; Sibiriak, Y.; Siddhanta, S.; Sielewicz, K. M.; Siemiarczuk, T.; Silvermyr, D.; Silvestre, C.; Simatovic, G.; Simonetti, G.; Singaraju, R.; Singh, R.; Singhal, V.; Sinha, T.; Sitar, B.; Sitta, M.; Skaali, T. B.; Slupecki, M.; Smirnov, N.; Snellings, R. J. M.; Snellman, T. W.; Song, J.; Song, M.; Song, Z.; Soramel, F.; Sorensen, S.; Sozzi, F.; Spiriti, E.; Sputowska, I.; Spyropoulou-stassinaki, M.; Stachel, J.; Stan, I.; Stankus, P.; Stenlund, E.; Steyn, G.; Stiller, J. H.; Stocco, D.; Strmen, P.; Suaide, A. A. P.; Sugitate, T.; Suire, C.; Suleymanov, M.; Suljic, M.; Sultanov, R.; Šumbera, M.; Sumowidagdo, S.; Swain, S.; Szabo, A.; Szarka, I.; Szczepankiewicz, A.; Szymanski, M.; Tabassam, U.; Takahashi, J.; Tambave, G. J.; Tanaka, N.; Tarhini, M.; Tariq, M.; Tarzila, M. G.; Tauro, A.; Tejeda Muñoz, G.; Telesca, A.; Terasaki, K.; Terrevoli, C.; Teyssier, B.; Thäder, J.; Thakur, D.; Thomas, D.; Tieulent, R.; Tikhonov, A.; Timmins, A. R.; Toia, A.; Trogolo, S.; Trombetta, G.; Trubnikov, V.; Trzaska, W. H.; Tsuji, T.; Tumkin, A.; Turrisi, R.; Tveter, T. S.; Ullaland, K.; Uras, A.; Usai, G. L.; Utrobicic, A.; Vala, M.; Valencia Palomo, L.; Van Der Maarel, J.; Van Hoorne, J. W.; van Leeuwen, Marco; Vanat, T.; Vande Vyvre, P.; Varga, D.; Vargas, A.; Vargyas, M.; Varma, R.; Vasileiou, M.; Vasiliev, A.; Vauthier, A.; Vázquez Doce, O.; Vechernin, V.; Veen, A. M.; Velure, A.; Vercellin, E.; Vergara Limón, S.; Vernet, R.; Vickovic, L.; Viinikainen, J.; Vilakazi, Z.; Villalobos Baillie, O.; Villatoro Tello, A.; Vinogradov, A.; Vinogradov, L.; Virgili, T.; Vislavicius, V.; Viyogi, Y. P.; Vodopyanov, A.; Völkl, M. A.; Voloshin, K.; Voloshin, S. A.; Volpe, G.; Von Haller, B.; Vorobyev, I.; Vranic, D.; Vrláková, J.; Vulpescu, B.; Wagner, B.; Wagner, J.; Wang, H.; Wang, M.; Watanabe, D.; Watanabe, Y.; Weber, M.; Weber, S. G.; Weiser, D. F.; Wessels, J. P.; Westerhoff, U.; Whitehead, A. M.; Wiechula, J.; Wikne, J.; Wilk, G.; Wilkinson, J.; Willems, G. A.; Williams, M. C. S.; Windelband, B.; Winn, M.; Yalcin, S.; Yang, P.; Yano, S.; Yin, Z.; Yokoyama, H.; Yoo, I.-k.; Yoon, J. H.; Yurchenko, V.; Zaborowska, A.; Zaccolo, V.; Zaman, A.; Zampolli, C.; Zanoli, H. J. C.; Zaporozhets, S.; Zardoshti, N.; Zarochentsev, A.; Závada, P.; Zaviyalov, N.; Zbroszczyk, H.; Zgura, I. S.; Zhalov, M.; Zhang, H.; Zhang, X.; Zhang, Y.; Zhang, C.; Zhang, Z.; Zhao, C.; Zhigareva, N.; Zhou, D.; Zhou, Y.; Zhou, Z.; Zhu, H.; Zhu, J.; Zichichi, A.; Zimmermann, A.; Zimmermann, M. B.; Zinovjev, G.; Zyzak, M.

    2016-01-01

    The elliptic, triangular, quadrangular and pentagonal anisotropic flow coefficients for π±, K± and p+p ¯ ¯ ¯ p+p¯ in Pb-Pb collisions at s NN − − − √ =2.76 sNN=2.76 TeV were measured with the ALICE detector at the Large Hadron Collider. The results were obtained with the Scalar Product method,

  20. Inbreeding depression for reproductive and yield related traits in S1 lines of maize (Zea mays L.

    Directory of Open Access Journals (Sweden)

    Sajid Khan

    2006-11-01

    Full Text Available This research was conducted to determine inbreeding depression in S1 maize lines for reproductive and yield related traits, at NWFP Agricultural University, Peshawar, Pakistan, in two successive seasons during 2002. Maize variety"Pahari" was selfed for one generation and 63 S1 lines were evaluated using "lattice square design" with two replications along with the parental population. Days to mid silking and mid pollen shed (anthesis, plant height and ear height (cm, and 200 grain weight (g showed inbreeding depression with varying degrees. Severe inbreeding depression was observed for yield with the average of 709 kg ha-1. Inbreeding depression for 200 grains weight averaged 19 g, while for plant height and ear height it was calculated as 33 and 16 cm. Inbreeding depression for days to mid silking and pollen shed was lower as compared to morphological and yield components. Silking and pollen shed were delayed by 1.8 and 1.5 days on the average, respectively, as compared to the parental variety. Yield was significantly correlated with all maturity and morphological characters. Maturity characters were positively and significantly correlated with each other, showing good synchronization in maturity characters, while they were negatively and significantly correlated with yield components.

  1. Sex-biased inbreeding effects on reproductive success and home range size of the critically endangered black rhinoceros.

    Science.gov (United States)

    Cain, Bradley; Wandera, Antony B; Shawcross, Susan G; Edwin Harris, W; Stevens-Wood, Barry; Kemp, Stephen J; Okita-Ouma, Benson; Watts, Phillip C

    2014-04-01

    A central premise of conservation biology is that small populations suffer reduced viability through loss of genetic diversity and inbreeding. However, there is little evidence that variation in inbreeding impacts individual reproductive success within remnant populations of threatened taxa, largely due to problems associated with obtaining comprehensive pedigree information to estimate inbreeding. In the critically endangered black rhinoceros, a species that experienced severe demographic reductions, we used model selection to identify factors associated with variation in reproductive success (number of offspring). Factors examined as predictors of reproductive success were age, home range size, number of nearby mates, reserve location, and multilocus heterozygosity (a proxy for inbreeding). Multilocus heterozygosity predicted male reproductive success (p58%) and correlated with male home range size (p 44%). Such effects were not apparent in females, where reproductive success was determined by age (p < 0.01, explained deviance 34%) as females raise calves alone and choose between, rather than compete for, mates. This first report of a 3-way association between an individual male's heterozygosity, reproductive output, and territory size in a large vertebrate is consistent with an asymmetry in the level of intrasexual competition and highlights the relevance of sex-biased inbreeding for the management of many conservation-priority species. Our results contrast with the idea that wild populations of threatened taxa may possess some inherent difference from most nonthreatened populations that necessitates the use of detailed pedigrees to study inbreeding effects. Despite substantial variance in male reproductive success, the increased fitness of more heterozygous males limits the loss of heterozygosity. Understanding how individual differences in genetic diversity mediate the outcome of intrasexual competition will be essential for effective management, particularly

  2. Fitness costs predict inbreeding aversion irrespective of self-involvement: support for hypotheses derived from evolutionary theory.

    Science.gov (United States)

    Antfolk, Jan; Lieberman, Debra; Santtila, Pekka

    2012-01-01

    It is expected that in humans, the lowered fitness of inbred offspring has produced a sexual aversion between close relatives. Generally, the strength of this aversion depends on the degree of relatedness between two individuals, with closer relatives inciting greater aversion than more distant relatives. Individuals are also expected to oppose acts of inbreeding that do not include the self, as inbreeding between two individuals posits fitness costs not only to the individuals involved in the sexual act, but also to their biological relatives. Thus, the strength of inbreeding aversion should be predicted by the fitness costs an inbred child posits to a given individual, irrespective of this individual's actual involvement in the sexual act. To test this prediction, we obtained information about the family structures of 663 participants, who reported the number of same-sex siblings, opposite-sex siblings, opposite-sex half siblings and opposite-sex cousins. Each participant was presented with three different types of inbreeding scenarios: 1) Participant descriptions, in which participants themselves were described as having sex with an actual opposite-sex relative (sibling, half sibling, or cousin); 2) Related third-party descriptions, in which participants' actual same-sex siblings were described as having sex with their actual opposite-sex relatives; 3) Unrelated third-party descriptions, in which individuals of the same sex as the participants but unrelated to them were described as having sex with opposite-sex relatives. Participants rated each description on the strength of sexual aversion (i.e., disgust-reaction). We found that unrelated third-party descriptions elicited less disgust than related third-party and participant descriptions. Related third-party and participant descriptions elicited similar levels of disgust suggesting that the strength of inbreeding aversion is predicted by inclusive fitness costs. Further, in the related and unrelated conditions

  3. Fitness costs predict inbreeding aversion irrespective of self-involvement: support for hypotheses derived from evolutionary theory.

    Directory of Open Access Journals (Sweden)

    Jan Antfolk

    Full Text Available It is expected that in humans, the lowered fitness of inbred offspring has produced a sexual aversion between close relatives. Generally, the strength of this aversion depends on the degree of relatedness between two individuals, with closer relatives inciting greater aversion than more distant relatives. Individuals are also expected to oppose acts of inbreeding that do not include the self, as inbreeding between two individuals posits fitness costs not only to the individuals involved in the sexual act, but also to their biological relatives. Thus, the strength of inbreeding aversion should be predicted by the fitness costs an inbred child posits to a given individual, irrespective of this individual's actual involvement in the sexual act. To test this prediction, we obtained information about the family structures of 663 participants, who reported the number of same-sex siblings, opposite-sex siblings, opposite-sex half siblings and opposite-sex cousins. Each participant was presented with three different types of inbreeding scenarios: 1 Participant descriptions, in which participants themselves were described as having sex with an actual opposite-sex relative (sibling, half sibling, or cousin; 2 Related third-party descriptions, in which participants' actual same-sex siblings were described as having sex with their actual opposite-sex relatives; 3 Unrelated third-party descriptions, in which individuals of the same sex as the participants but unrelated to them were described as having sex with opposite-sex relatives. Participants rated each description on the strength of sexual aversion (i.e., disgust-reaction. We found that unrelated third-party descriptions elicited less disgust than related third-party and participant descriptions. Related third-party and participant descriptions elicited similar levels of disgust suggesting that the strength of inbreeding aversion is predicted by inclusive fitness costs. Further, in the related and

  4. Slow inbred lines of Drosophila melanogaster express as much inbreeding depression as fast inbred lines under semi-natural conditions

    DEFF Research Database (Denmark)

    Kristensen, Torsten Nygård; Knudsen, Morten Ravn; Loeschcke, Volker

    2011-01-01

    Selection may reduce the deleterious consequences of inbreeding. This may be due to purging of recessive deleterious alleles or balancing selection favouring heterozygote offspring. Such selection is expected to be more efficient at slower compared to at faster rates of inbreeding. In this study ...

  5. Transport Coefficients of Fluids

    CERN Document Server

    Eu, Byung Chan

    2006-01-01

    Until recently the formal statistical mechanical approach offered no practicable method for computing the transport coefficients of liquids, and so most practitioners had to resort to empirical fitting formulas. This has now changed, as demonstrated in this innovative monograph. The author presents and applies new methods based on statistical mechanics for calculating the transport coefficients of simple and complex liquids over wide ranges of density and temperature. These molecular theories enable the transport coefficients to be calculated in terms of equilibrium thermodynamic properties, and the results are shown to account satisfactorily for experimental observations, including even the non-Newtonian behavior of fluids far from equilibrium.

  6. Linking inbreeding effects in captive populations with fitness in the wild: Release of replicated Drosophila melanogaster lines under different temperatures

    DEFF Research Database (Denmark)

    Kristensen, Torsten Nygård; Loeschcke, Volker; Hoffmann, Ary A.

    2008-01-01

    Inbreeding effects have been detected in captive populations of threatened species, but the extent to which these effects translate into fitness under field conditions is mostly unknown. We address this issue by comparing the performance of replicated noninbred and inbred Drosophila lines under...... conditions and involve traits not easily measured under laboratory conditions. More generally, inbreeding effects measured in captive populations may not necessarily predict their field performance, and programs to purge captive populations of deleterious alleles may not necessarily lead to fitness benefits...

  7. Genetic variation, inbreeding and chemical exposure—combined effects in wildlife and critical considerations for ecotoxicology

    Science.gov (United States)

    Brown, A. Ross; Hosken, David J.; Balloux, François; Bickley, Lisa K.; LePage, Gareth; Owen, Stewart F.; Hetheridge, Malcolm J.; Tyler, Charles R.

    2009-01-01

    Exposure to environmental chemicals can have negative consequences for wildlife and even cause localized population extinctions. Resistance to chemical stress, however, can evolve and the mechanisms include desensitized target sites, reduced chemical uptake and increased metabolic detoxification and sequestration. Chemical resistance in wildlife populations can also arise independently of exposure and may be spread by gene flow between populations. Inbreeding—matings between closely related individuals—can have negative fitness consequences for natural populations, and there is evidence of inbreeding depression in many wildlife populations. In some cases, reduced fitness in inbred populations has been shown to be exacerbated under chemical stress. In chemical testing, both inbred and outbred laboratory animals are used and for human safety assessments, iso-genic strains (virtual clones) of mice and rats are often employed that reduce response variation, the number of animals used and associated costs. In contrast, for environmental risk assessment, strains of animals are often used that have been selectively bred to maintain heterozygosity, with the assumption that they are better able to predict adverse effects in wild, genetically variable, animals. This may not necessarily be the case however, as one outbred strain may not be representative of another or of a wild population. In this paper, we critically discuss relationships between genetic variation, inbreeding and chemical effects with the intention of seeking to support more effective chemical testing for the protection of wildlife. PMID:19833649

  8. Intraspecific Competition and Inbreeding Depression: Increased Competitive Effort by Inbred Males Is Costly to Outbred Opponents.

    Science.gov (United States)

    Richardson, Jon; Smiseth, Per T

    2017-05-01

    A recent theoretical model suggests that intraspecific competition is an important determinant of the severity of inbreeding depression. The reason for this is that intraspecific competition is density dependent, leading to a stronger negative effect on inbred individuals if they are weaker competitors than outbred ones. In support of this prediction, previous empirical work shows that inbred individuals are weaker competitors than outbred ones and that intraspecific competition often exacerbates inbreeding depression. Here, we report an experiment on the burying beetle Nicrophorus vespilloides, in which we recorded the outcome of competition over a small vertebrate carcass between an inbred or outbred male resident caring for a brood and a size-matched inbred or outbred male intruder. We found that inbred males were more successful as intruders in taking over a carcass from a male resident and were injured more frequently as either residents or intruders. Furthermore, inbred males gained less mass during the breeding attempt and had a shorter adult life span than outbred males. Finally, successful resident males reared a substantially smaller brood comprised of lighter larvae when the intruder was inbred than when it was outbred. Our results shows that inbred males increased their competitive effort, thus contradicting previous work suggesting that inbred males are weaker competitors. Furthermore, our results shows that inbred intruders impose a greater cost to resident males, suggesting that outbred individuals can suffer fitness costs as a result of competition with inbred ones.

  9. Inbreeding depression in Solanum carolinense (Solanaceae under field conditions and implications for mating system evolution.

    Directory of Open Access Journals (Sweden)

    Rupesh R Kariyat

    Full Text Available The clonal weed Solanum carolinense exhibits plasticity in the strength of its self-incompatibility (SI system and suffers low levels of inbreeding depression (δ in the greenhouse. We planted one inbred and one outbred plant from each of eight maternal plants in a ring (replicated twice and monitored clonal growth, herbivory, and reproduction over two years. Per ramet δ was estimated to be 0.63 in year one and 0.79 in year two, and outbred plants produced 2.5 times more ramets than inbred plants in the spring of year two. Inbred plants also suffered more herbivore damage than outbred plants in both fields, suggesting that inbreeding compromises herbivore resistance. Total per genet δ was 0.85 over the two years, indicating that S. carolinense is unlikely to become completely self-compatible, and suggesting that plasticity in the SI system is part of a stable mixed-mating system permitting self-fertilization when cross pollen limits seed production.

  10. Inbreeding depression for seed germination and seedling vigor in strawberry (Fragaria × ananassa Duch.

    Directory of Open Access Journals (Sweden)

    Kaczmarska Elżbieta

    2014-12-01

    Full Text Available Experiments leading to the procurement of subsequent inbred generations were conducted in the years 2006- 2013. Seeds obtained from open pollination and after self-pollination of four strawberry cultivars (Teresa, Senga Sengana, Kent and Chandler and clone 1387 were used. These genotypes were evaluated for their tolerance to strong inbreeding under in vitro culture conditions. The aims of this study were to estimate the inbreeding depression of each of the progenies. During the investigation, the germination percentage as well as seedling viability were evaluated. The highest seed germination was shown for populations derived from ‘Teresa’ × open pollination (82% and ‘Kent’ (7 S4 (78%. Seeds derived from self-pollination resulted in the lowest germination - an average of 16.8%. Generally, seed germination was significantly lower for the five S1 offspring, whose depression was 0.62, in comparison with the S4 seedlings, whose depression was 0.31. Inbred offspring showed a depression in relation to the average weight of a single seedling of 0.08 in the case of S1 progeny, whereas in the case of S4 progeny it was 0.23. The highest germination energy was shown by ‘Kent’ (7 S4 seeds (74% and hybrids of ‘Teresa’ derived from open pollination (75%; whereas seeds obtained at the same time from self-pollination germinated 10.8% on average.

  11. Marker-assisted selection reduces expected inbreeding but can result in large effects of hitchhiking

    DEFF Research Database (Denmark)

    Pedersen, L D; Sørensen, A C; Berg, P

    2010-01-01

    We used computer simulations to investigate to what extent true inbreeding, i.e. identity-by-descent, is affected by the use of marker-assisted selection (MAS) relative to traditional best linear unbiased predictions (BLUP) selection. The effect was studied by varying the heritability (h2 = 0.04 vs....... 0.25), the marker distance (MAS vs. selection on the gene, GAS), the favourable QTL allele effect (α = 0.118 vs. 0.236) and the initial frequency of the favourable QTL allele (p = 0.01 vs. 0.1) in a population resembling the breeding nucleus of a dairy cattle population. The simulated genome...... consisted of two chromosomes of 100 cM each in addition to a polygenic component. On chromosome 1, a biallelic QTL as well as 4 markers were simulated in linkage disequilibrium. Chromosome 2 was selectively neutral. The results showed that, while reducing pedigree estimated inbreeding, MAS and GAS did...

  12. Basal and induced granulopoiesis in outbred, F1 hybrid and inbred mice: can inbreeding depression influence the experimental practice?

    Czech Academy of Sciences Publication Activity Database

    Hofer, Michal; Pospíšil, Milan; Dušek, L.; Holá, Jiřina; Hoferová, Zuzana; Weiterová, Lenka

    2010-01-01

    Roč. 235, č. 8 (2010), s. 928-931 ISSN 1535-3702 R&D Projects: GA ČR(CZ) GA305/08/0158 Institutional research plan: CEZ:AV0Z50040507; CEZ:AV0Z50040702 Keywords : hematopoiesis * outbred mice * inbreeding depression Subject RIV: BO - Biophysics Impact factor: 2.954, year: 2010

  13. Deepening Our Understanding of Academic Inbreeding Effects on Research Information Exchange and Scientific Output: New Insights for Academic Based Research

    Science.gov (United States)

    Horta, Hugo

    2013-01-01

    This paper analyzes the impact of academic inbreeding in relation to academic research, and proposes a new conceptual framework for its analysis. We find that mobility (or lack of) at the early research career stage is decisive in influencing academic behaviors and scientific productivity. Less mobile academics have more inward oriented…

  14. Strategic promiscuity helps avoid inbreeding at multiple levels in a cooperative breeder where both sexes are philopatric

    NARCIS (Netherlands)

    Brouwer, Lyanne; van de Pol, Martijn; Atema, Els; Cockburn, Andrew

    2011-01-01

    In cooperative breeders, the tension between the opposing forces of kin selection and kin competition is at its most severe. Although philopatry facilitates kin selection, it also increases the risk of inbreeding. When dispersal is limited, extra-pair paternity might be an important mechanism to

  15. Heterotic studies and inbreeding depression in f/sub 2/populations of upland cotton

    International Nuclear Information System (INIS)

    Panni, M.K.

    2012-01-01

    To study the genetic potential, heterotic effects and inbreeding depression, 8 X 8 F/sub 2/diallel populations with parental lines of upland cotton were grown during crop season 2010 in a randomized complete block design at Khyber Pakhtunkhwa Agricultural University Peshawar, Pakistan. Highly significant ( p = 0.01 ) variations were noticed among parental lines and F/sub 2/ populations for all the traits. According to genotypes mean performance for various traits, plant height varied from 101.60 to 126.30 cm and 98.60 to 140.60 cm, bolls plant/sup -1/ (12.87 to 19.53; 12.13 to 22.60), boll weight (3.80 to 5.01 g; 3.04 to 5.38 g) and seed cotton yield plant/sup -1/ varied from 55.74 to 85.47 g and 45.57 to 96.05 g in parental cultivars and their F/sub 2/ populations, respectively. However, 12 and 7 F/sub 2/ populations manifested significant heterosis over mid and better parents for plant height, 7 and 3 for bolls plant/sup -1/, 13 and 9 for boll weight and 13 and 5 F/sub 2/ populations for seed cotton yield plant/sup -1/, respectively. F/sub 2/ populations i.e. CIM-554 X CIM-473, CIM-554 X CIM-499, CIM-496 X SLH-284, CIM-473 X CIM-446 and CIM-554 X SLH-284 with low mean values for plant height performed better and manifested highly significant heterotic values over mid and better parents for bolls per plant, boll weight and seed cotton yield. By comparing F/sub 2/ mean values with F/sub 1/s, inbreeding depression was observed for plant height (0.66 to 23. 99%), bolls per plant (5.00 to 63.16%), boll weight (0.20 to 23.24%) and seed cotton yield (0.44 to 75.52%). However, 62% of F/sub 2/ populations revealed negative values for inbreeding depression, 14% for bolls per plant, 77% for boll weight and 21% for yield, revealed that these F/sub 2/ populations were more stable and performed better than F/sub 1/s even after segregation. Although, F/sub 2/ populations may display less heterosis as compared to F/sub 1/, but still better than high parents and can be used as

  16. Marker Assisted Selection can Reduce True as well as Pedigree Estimated Inbreeding

    DEFF Research Database (Denmark)

    Pedersen, L D; Sørensen, A C; Berg, P

    2009-01-01

    ) with an initial frequency of the favorable allele of 0.1, and initially explaining 25% of the genetic variance as well as 4 markers were simulated in linkage disequilibrium, all positioned at chromosome 1. Chromosome 2 was selectively neutral, and consisted of a single neutral locus. The results showed......This study investigated whether selection using genotype information reduced the rate and level of true inbreeding, that is, identity by descent, at a selectively neutral locus as well as a locus under selection compared with traditional BLUP selection. In addition, the founder representation...... at these loci and the within-family selection at the nonneutral locus were studied. The study was carried out using stochastic simulation of a population resembling the breeding nucleus of a dairy cattle population for 25 yr. Each year, 10 proven bulls were selected across herds along with 100 dams from within...

  17. Genetic diversity, inbreeding and breeding practices in dogs: results from pedigree analyses.

    Science.gov (United States)

    Leroy, Grégoire

    2011-08-01

    Pedigree analysis constitutes a classical approach for the study of the evolution of genetic diversity, genetic structure, history and breeding practices within a given breed. As a consequence of selection pressure, management in closed populations and historical bottlenecks, many dog breeds have experienced considerable inbreeding and show (on the basis of a pedigree approach) comparable diversity loss compared to other domestic species. This evolution is linked to breeding practices such as the overuse of popular sires or mating between related animals. The popular sire phenomenon is the most problematic breeding practice, since it has also led to the dissemination of a large number of inherited defects. The practice should be limited by taking measures such as restricting the number of litters (or offspring) per breeding animal. Copyright © 2011 Elsevier Ltd. All rights reserved.

  18. Prestarlike functions with negative coefficients

    Directory of Open Access Journals (Sweden)

    H. Silverman

    1979-01-01

    Full Text Available The extreme points for prestarlike functions having negative coefficients are determined. Coefficient, distortion and radii of univalence, starlikeness, and convexity theorems are also obtained.

  19. Heterotic effects in f/sub 1s/ and inbreeding depression in f/sub 2/ hybrids of sunflower

    International Nuclear Information System (INIS)

    Memon, S.; Baloch, M.J.; Baloch, G.M.

    2015-01-01

    genetically diverse female lines of sunflower were crossed with male testers to get heterotic hybrids. studies were carried-out during 2008-2010 at experiment filed of agriculture research institute, tandojam, sindh, pakistan. six female lines like t-4-0319, pac-0505, ho-i, hysun-33, peshawar-93 and cms-03 and three testers i.e., pac-0306, pac-64-a and sf-187 were crossed in a line * tester mating design, thus 18 f1 and f2 hybrids were developed for evaluation of heterosis and inbreeding depression for days to initial flowering, days to maturity, leaves/plant, plant height (cm), head diameter (cm), 1000-achene weight (g), seed yield kg/ha and oil yield kg/ha. the experiment was conducted in a randomised completeb lock design with four replications. the analysis of variance revealed significant differences among parents, f1s and f2 hybrids for all the traits studied. the existence of significant genetic variability among the plant traits is particularly useful because variations in these traits would allow further improvement in sunflower seed yield and oil traits. the f1 hybrids ho-i * pac-0306 and ho-i pa * c-64-a exhibited desirable negative mid and better parent heterosis for days to initial flowering, days to maturity and plant height. these hybrids also manifested desirable positive heterotic effects for leaves/plant, head diameter, 1000-achene.s weight, seed yield and oil yield. inbreeding depression for phenological, seed yield and oil traits showed that desirable high inbreeding depression was observed in hybrids ho-i * p*ac-64-a, ho-i * pac-0306 and ho-i * sf-187 for days to initial flowering, similarly t-4-0319 * pac-0306, pac-0505 ± sf-187 and ho-i * pac-64-a explicated maximum but rewarding inbreeding depression for days to maturity. the f2 hybrids hysun-33 * sf-187 and peshawer-93 * pac-64-a may be the most desirable ones in the sense that they recorded comparatively moderate inbreeding depression with enough number of leaves to be productive if f2

  20. Evolution of Inbreeding and Outcrossing in Ferns and Fern-Allies(US-JAPAN SEMINAR : EVOLUTIONARY STUDIES ON SEXUAL SYSTEMS IN PLANTS)

    OpenAIRE

    PAMELA S., SOLTIS; DOUGLAS E., SOLTIS; Department of Botany, Washington State University; Department of Botany, Washington State University

    1990-01-01

    Mating systems of 18 species of homosporous ferns follow a bimodal distribution, similar to that observed for seed plants (Schemske and Lande, 1985). Most species are highly outcrossing, a few are inbreeding, and two species examined to date have mixed mating systems. Equisetum arvense and several species of lycopods are also highly outcrossing. Several mechanisms, including inbreeding depression, antheridiogen, and ontogenetic sequences that result in effectively unisexual gametophytes, prom...

  1. Sex differences in the genetic architecture of lifespan in a seed beetle: extreme inbreeding extends male lifespan

    DEFF Research Database (Denmark)

    Bilde, T.; Maklakov, Alexei A.; Meisner, Katrine

    2009-01-01

    Background Sex differences in lifespan are ubiquitous throughout the animal kingdom but the causes underlying this phenomenon remain poorly understood. Several explanations based on asymmetrical inheritance patterns (sex chromosomes or mitochondrial DNA) have been proposed, but these ideas have...... rarely been tested experimentally. Alternatively, sexual dimorphism in lifespan could result from sex-specific selection, caused by fundamental differences in how males and females optimize their fitness by allocating resources into current and future reproduction. Results Here we used sex......-specific responses to inbreeding to study the genetic architecture of lifespan and mortality rates in Callosobruchus maculatus, a seed beetle that shows sexual dimorphism in lifespan. Two independent assays revealed opposing sex-specific responses to inbreeding. The combined data set showed that inbred males live...

  2. The "unguarded-X" and the genetic architecture of lifespan: Inbreeding results in a potentially maladaptive sex-specific reduction of female lifespan in Drosophila melanogaster.

    Science.gov (United States)

    Sultanova, Zahida; Andic, Muhammed; Carazo, Pau

    2018-03-01

    Sex differences in ageing and lifespan are ubiquitous in nature. The "unguarded-X" hypothesis (UXh) suggests they may be partly due to the expression of recessive mutations in the hemizygous sex chromosomes of the heterogametic sex, which could help explain sex-specific ageing in a broad array of taxa. A prediction central to the UX hypothesis is that inbreeding will decrease the lifespan of the homogametic sex more than the heterogametic sex, because only in the former does inbreeding increase the expression of recessive deleterious mutations. In this study, we test this prediction by examining the effects of inbreeding on the lifespan and fitness of male and female Drosophila melanogaster across different social environments. We found that, across social environments, inbreeding resulted in a greater reduction of female than male lifespan, and that inbreeding effects on fitness did not seem to counterbalance sex-specific effects on lifespan, suggesting the former are maladaptative. Inter- and intra-sexual correlation analyses also allowed us to identify evidence of an underlying joint genetic architecture for inbreeding effects on lifespan. We discuss these results in light of the UXh and other alternative explanations, and suggest that more attention should be paid to the possibility that the "unguarded-X" may play an important role in the evolution of sex-specific lifespan. © 2018 The Author(s). Evolution © 2018 The Society for the Study of Evolution.

  3. Sex-biased natal dispersal and inbreeding avoidance in American black bears as revealed by spatial genetic analyses.

    Science.gov (United States)

    Costello, Cecily M; Creel, Scott R; Kalinowski, Steven T; Vu, Ninh V; Quigley, Howard B

    2008-11-01

    We tested the hypothesis that sex-biased natal dispersal reduces close inbreeding in American black bears, a solitary species that exhibits nearly complete male dispersal and female philopatry. Using microsatellite DNA and spatial data from reproductively mature bears (>or= 4 years old), we examined the spatial genetic structure of two distinct populations in New Mexico from 1993 to 2000. As predicted, relatedness (r) and the frequency of close relationships (parent-offspring or full siblings) decreased with distance among female dyads, but little change was observed among male or opposite-sex dyads. Neighbouring females were more closely related than neighbouring males. The potential for inbreeding was low. Most opposite-sex pairs that lived sufficiently close to facilitate mating were unrelated, and few were close relatives. We found no evidence that bears actively avoided inbreeding in their selection of mates from this nearby pool, as mean r and relationship frequencies did not differ between potential and actual mating pairs (determined by parentage analysis). These basic patterns were apparent in both study areas despite a nearly two-fold difference in density. However, the sex bias in dispersal was less pronounced in the lower-density area, based on proportions of bears with male and female relatives residing nearby. This result suggests that male bears may respond to reduced competition by decreasing their rate or distance of dispersal. Evidence supports the hypothesis that inbreeding avoidance is achieved by means of male-biased dispersal but also indicates that competition (for mates or resources) modifies dispersal patterns.

  4. Evidence of high inbreeding in a population of the endangered giant anteater, Myrmecophaga tridactyla (Myrmecophagidae), from Emas National Park, Brazil

    OpenAIRE

    Collevatti, Rosane G.; Leite, Kelly C.E.; Miranda, Guilherme H.B. de; Rodrigues, Flavio H.G.

    2007-01-01

    We report the genetic structure, relatedness and mating structure of a population of the endangered giant anteater Myrmecophaga tridactyla Linnaeus, 1758 in the Emas National Park, Brazil, based on variability at five microsatellite loci. Additionally, we addressed the hypothesis that the M. tridactyla population studied has low levels of polymorphism and high levels of inbreeding and relatedness and that animals with overlapping home range are highly related. All five microsatellite loci dis...

  5. Estimation of inbreeding rates and extinction risk of forty one Belgian chicken breeds in 2005 and 2010

    OpenAIRE

    Moula, Nassim; Philippe, François-Xavier; Antoine-Moussiaux, Nicolas; Leroy, Pascal; Michaux, Charles

    2014-01-01

    In Belgium, as generally in Europe, the dominant position of the high producing commercial strains specialized in meat or eggs production threats of extinction the local traditional breeds. In this work, a follow up of the changes in populations size, and the rates of inbreeding of the Belgian poultry breeds, has been carried out in 2005 and 2010. About forty breeds were concerned. The Belgian hen breeds being overwhelmingly under threat of extinction, because of the low number of individu...

  6. Quality of the Exotic Parasitoid Cotesia flavipes (Hymenoptera: Braconidae) Does Not Show Deleterious Effects after Inbreeding for 10 Generations.

    Science.gov (United States)

    Trevisan, Maíra; De Bortoli, Sergio A; Vacari, Alessandra M; Laurentis, Valéria L; Ramalho, Dagmara G

    2016-01-01

    Although the parasitoid Cotesia flavipes (Cameron) has proven effective in controlling sugarcane borer Diatraea saccharalis (Fabricius) for many years, concern has arisen over the quality of individuals produced at large scales. The parasitoid has been reared in laboratories in Brazil for more than 40 years, with no new introductions of new populations during that period. Since the quality of the parasitoids was not verified at the time of the species' introduction in Brazil, we do not know if there has been any reduction in quality so far. However, it is possible to determine whether the parasitoid could reduce in quality in future generations. Thus, the objective of this research was to assess the quality of these insects over 10 generations and look for evidence of any loss in quality. We used two populations: one from a biofactory that has been maintained in the laboratory for over 40 years, and an inbred laboratory population. Both were bred, and compared for 10 generations. We wanted to determine what happened to the quality of the parasitoid after 10 generations in an extreme inbreeding situation. To assure inbreeding, newly emerged females were forced to mate with a sibling. Individual females were then allowed to parasitize larvae of D. saccharalis. We performed evaluations for each generation until the tenth generation, and recorded the sex ratio, percentage emergence, number of offspring/females, and longevity of both males and females. Results of the measurements of biological characteristics demonstrated random significant differences between populations; best results were obtained intermittently for both the biofactory population and the inbred population. No significant differences across generations for the same population were observed. Thus, rearing of a C. flavipes population subjected to inbreeding for 10 generations was not sufficient to reveal any deleterious effects of inbreeding.

  7. Extinction of mammalian populations in conservation units of the Brazilian Cerrado by inbreeding depression in stochastic environments

    OpenAIRE

    Silva, Marcel Müller Fernandes Pereira da; Diniz-Filho, José Alexandre Felizola

    2008-01-01

    Despite methodological and theoretical advances in conservation genetics, data on genetic variation on broad regional spatial scales are still scarce, leading conservation planners to use general heuristic or simulation models for an integrated analysis of genetic, demographic and landscape parameters. Here, we extended previous results by evaluating spatial patterns of extinction by inbreeding depression under stochastic variation of environments for mammalian populations in 31 conservation ...

  8. Inbreeding avoidance, patch isolation and matrix permeability influence dispersal and settlement choices by male agile antechinus in a fragmented landscape.

    Science.gov (United States)

    Banks, Sam C; Lindenmayer, David B

    2014-03-01

    Animal dispersal is highly non-random and has important implications for the dynamics of populations in fragmented habitat. We identified interpatch dispersal events from genetic tagging, parentage analyses and assignment tests and modelled the factors associated with apparent emigration and post-dispersal settlement choices by individual male agile antechinus (Antechinus agilis, a marsupial carnivore of south-east Australian forests). Emigration decisions were best modelled with on data patch isolation and inbreeding risk. The choice of dispersal destination by males was influenced by inbreeding risk, female abundance, patch size, patch quality and matrix permeability (variation in land cover). Males were less likely to settle in patches without highly unrelated females. Our findings highlight the importance of individual-level dispersal data for understanding how multiple processes drive non-randomness in dispersal in modified landscapes. Fragmented landscapes present novel environmental, demographic and genetic contexts in which dispersal decisions are made, so the major factors affecting dispersal decisions in fragmented habitat may differ considerably from unfragmented landscapes. We show that the spatial scale of genetic neighbourhoods can be large in fragmented habitat, such that dispersing males can potentially settle in the presence of genetically similar females after moving considerable distances, thereby necessitating both a choice to emigrate and a choice of where to settle to avoid inbreeding. © 2013 The Authors. Journal of Animal Ecology © 2013 British Ecological Society.

  9. Correlation and path coefficient analysis of some quantitative traits ...

    African Journals Online (AJOL)

    Thirty-seven wheat genotypes and three check varieties were studied for correlation and path coefficient analysis of some quantitative traits in wheat at Kisan (P.G), College, Simbhaoli in India. Generally, the estimates of genotypic correlation coefficients were higher than the corresponding phenotypic correlation coefficients ...

  10. Coefficient estimates of negative powers and inverse coefficients for ...

    Indian Academy of Sciences (India)

    λ. Using this we shall determine the ... Univalent; starlike; meromorphic functions; subordination; coefficient bounds; inverse ...... [6] FitzGerald C H, Quadratic inequalities and coefficient estimates for Schlicht functions, Arch. Ration. Mech. Anal.

  11. Disruption of endosperm development: an inbreeding effect in almond (Prunus dulcis).

    Science.gov (United States)

    Ortega, Encarnación; Martínez-García, Pedro J; Dicenta, Federico; Egea, José

    2010-06-01

    A homozygous self-compatible almond, originated from self-fertilization of a self-compatible genotype and producing a reasonable yield following open pollination, exhibited a very high fruit drop rate when self-pollinated. To investigate whether fruit dropping in this individual is related to an abnormal development of the embryo sac following self-fertilization, histological sections of ovaries from self and cross-pollinated flowers were observed by light microscopy. Additionally, the presence of pollen tubes in the ovary and fruit set were determined for both types of pollination. Despite pollen tubes reached the ovary after both pollinations, differences in embryo sac and endosperm development after fertilization were found. Thus, while for cross-fertilized ovules a pro-embryo and an endosperm with abundant nuclei were generally observed, most self-fertilized ovules remained in a previous developmental stage in which the embryo sac was not elongated and endosperm nuclei were absent. Although 30 days after pollination fruit set was similar for both pollination types, at 60 days it was significantly reduced for self-pollination. These results provide evidence that the high fruit drop in this genotype is the consequence of a disrupted development of the endosperm, what could be an expression of its high level of inbreeding.

  12. Positive feedback and alternative stable states in inbreeding, cooperation, sex roles and other evolutionary processes

    Science.gov (United States)

    Lehtonen, Jussi; Kokko, Hanna

    2012-01-01

    A large proportion of studies in systems science focus on processes involving a mixture of positive and negative feedbacks, which are also common themes in evolutionary ecology. Examples of negative feedback are density dependence (population regulation) and frequency-dependent selection (polymorphisms). Positive feedback, in turn, plays a role in Fisherian ‘runaway’ sexual selection, the evolution of cooperation, selfing and inbreeding tolerance under purging of deleterious alleles, and the evolution of sex differences in parental care. All these examples feature self-reinforcing processes where the increase in the value of a trait selects for further increases, sometimes via a coevolutionary feedback loop with another trait. Positive feedback often leads to alternative stable states (evolutionary endpoints), making the interpretation of evolutionary predictions challenging. Here, we discuss conceptual issues such as the relationship between self-reinforcing selection and disruptive selection. We also present an extension of a previous model on parental care, focusing on the relationship between the operational sex ratio and sexual selection, and the influence of this relationship on the evolution of biparental or uniparental care. PMID:22144384

  13. Implications of nonadventitious rhizome spread on reproduction, inbreeding, and conservation for a rare grassland legume.

    Science.gov (United States)

    Severns, Paul M; Liston, Aaron; Wilson, Mark V

    2011-01-01

    Small population size, genetic diversity, and spatial patterns of vegetative spread are important aspects to consider when managing populations of rare clonal plant species. We used 5 variable nuclear simple sequence repeat nDNA loci to determine the extent of genet rhizome spread, examine the possibility of very small population sizes, and project how Bombus spp. (bumblebee) foraging may impact selfing (through geitonogamy) for a threatened lupine (Lupinus oreganus Heller) that sprawls through nonadventitious rhizomes. Genotyping identified 1 genet (27 × 13 m) that dominated about 30% of a study site, whereas 15 genets spread a maximum average distance of about 5.5 m (range 1.6 -27.1 m) and appeared to be well integrated with intervening genets. We found unexpectedly high genotype diversity, no evidence of a recent genetic bottleneck, and 5 of 6 patches had mean fixation index values that were near Hardy-Weinberg Equilibrium expectations. If the median maximum Bombus foraging distance observed in lupine patches (1.2 m) occurred within genotyped populations, a typical foraging flight would have >80% chance of occurring between different genets. Our study demonstrates that inferences associated with clonality, small population size, and inbreeding depression should be directly evaluated for rare vegetatively spreading plants.

  14. Positive feedback and alternative stable states in inbreeding, cooperation, sex roles and other evolutionary processes.

    Science.gov (United States)

    Lehtonen, Jussi; Kokko, Hanna

    2012-01-19

    A large proportion of studies in systems science focus on processes involving a mixture of positive and negative feedbacks, which are also common themes in evolutionary ecology. Examples of negative feedback are density dependence (population regulation) and frequency-dependent selection (polymorphisms). Positive feedback, in turn, plays a role in Fisherian 'runaway' sexual selection, the evolution of cooperation, selfing and inbreeding tolerance under purging of deleterious alleles, and the evolution of sex differences in parental care. All these examples feature self-reinforcing processes where the increase in the value of a trait selects for further increases, sometimes via a coevolutionary feedback loop with another trait. Positive feedback often leads to alternative stable states (evolutionary endpoints), making the interpretation of evolutionary predictions challenging. Here, we discuss conceptual issues such as the relationship between self-reinforcing selection and disruptive selection. We also present an extension of a previous model on parental care, focusing on the relationship between the operational sex ratio and sexual selection, and the influence of this relationship on the evolution of biparental or uniparental care.

  15. Multiple Convergent Origins of Workerlessness and Inbreeding in the Socially Parasitic Ant Genus Myrmoxenus.

    Directory of Open Access Journals (Sweden)

    Jürgen Heinze

    Full Text Available The socially parasitic ant genus Myrmoxenus varies strongly in fundamental life history traits, such as queen-worker ratio, the timing of sexual production, and mating behavior. Myrmoxenus queens generally take over nests of Temnothorax ants, kill the resident queen by throttling, and force the workers to take care of the social parasite's brood. Young queens of M. ravouxi and other species produce large numbers of workers, which during "slave-raids" pillage host pupae from neighboring Temnothorax colonies to increase the workforce in their own nests. Other species, such as M. corsicus, have lost caste polyphenism and rear only male and female sexual offspring. Using sequences of the genes CO I/CO II and wingless we reconstruct the phylogeny of Myrmoxenus and document that the worker caste was lost convergently at least three times. Furthermore, mating in the nest and inbreeding obviously also evolved in parallel from ancestors whose sexuals presumably mated during nuptial flights. Myrmoxenus might thus provide a suitable model to investigate caste differentiation and the plasticity of mating behavior in Hymenoptera.

  16. Inbreeding and building up small populations of stingless bees (Hymenoptera, Apidae

    Directory of Open Access Journals (Sweden)

    Paulo Nogueira-Neto

    2002-12-01

    Full Text Available A study of the viability of small populations of Hymenoptera is a matter of importance to gain a better zoological, ethological, genetical and ecological knowledge of these insects, and for conservation purposes, mainly because of the consequences to the survival of colonies of many species of bees, wasps, and ants. Based on the Whiting (1943 principle, Kerr & Vencovski (1982 presented a hypothesis that states that viable populations of stingless bees (Meliponini should have at least 40 colonies to survive. This number was later extended to 44 colonies by Kerr (1985. This would be necessary to avoid any substantial amount of homozygosis in the pair of chromosomic sexual loci, by keeping at least six different sexual gene alleles in a reproductive population. In most cases this would prevent the production of useless diploid males. However, several facts weigh against considering this as a general rule. From 1990 to 2001, 287 colony divisions were made, starting with 28 foundation colonies, in the inbreeding and population experiments with the Meliponini reported here. These experiments constitute the most extensive and longest scientific research ever made with Meliponini bees. In ten different experiments presented here, seven species (one with two subspecies of Meliponini bees were inbred in five localities inside their wide-reaching native habitats, and in two localities far away from these habitats. This was done for several years. On the whole, the number of colonies increased and the loss of colonies over the years was small. In two of these experiments, although these populations were far (1,000 km and 1,200 km from their native habitat, their foundation colonies were multiplied successfuly. It was possible to build up seven strong and three expanding medium populations, starting with one, two, three or even five colonies. However, in six other cases examined here, the Whiting (1943 principle and the hypothesis of Kerr & Vencovski (1982

  17. Reproductive Behavior and Inbreeding Depression in Endangered Eremostachys superba Royle ex Benth. (Labiatae in Dehra Dun Population, India

    Directory of Open Access Journals (Sweden)

    Arti Garg

    2004-12-01

    Full Text Available An assessment of reproductive behavior and inbreeding depression, if any, in critically endangered Eremostachys superba Royle ex Benth. (Labiatae was made to unveil the factors playing vital role in it’s reproductive biology and which may be responsible for the loss of fitness, viability and vigor of the species. Breeding experiments portrayed a failure of self-fertilization and a strong tendency towards out-breeding as seed set by xenogamy was highest (44.4%. However, the narrow restricted population of the type locality in Dehra Dun Siwaliks was just a ramet population sustained by clonal propagation of rhizomatous root stock, hence any out-crossing within these homozygous individuals also amounted to inbreeding. Further, there is no other population available within the range of normal seed dispersal mechanism or insect-pollinator-flight-range. The other populations reported are only from geographically distant region of Jammu and Kashmir state of India, which is too far a distance to be covered by the Nomia rustica West. and Ceratina heiroglyphica Sm., the oligophilic pollinators of E. superba, hence any crossing taking place also amounts to selfing in strict sense. Chances of induction of genetic variation by crossing between two different populations are remote. This was also supported by the data of seed production and germination experiments. Even the healthy seeds suffered from loss of fitness and failed to germinate under natural conditions. This strongly indicated prevalence of inbreeding depression and loss of fitness of the progeny right from the stage of germination, a phenomenon hazardous for sustenance and perpetuation of species leading to rarity.

  18. Heterozygosity predicts clutch and egg size but not plasticity in a house sparrow population with no evidence of inbreeding.

    Science.gov (United States)

    Wetzel, Daniel P; Stewart, Ian R K; Westneat, David F

    2012-01-01

    We investigated the link between heterozygosity and the reaction norm attributes of reproductive performance in female house sparrows (Passer domesticus). We collected data on clutch size, egg size, hatching success and nestling survival in 2816 nesting attempts made by 791 marked individuals over a 16-year period. Pedigree analysis revealed no evidence of inbreeding. Neither parent-offspring regression nor an animal model revealed significant heritability in clutch or egg size. We selected 42 females that laid at least seven clutches at our study site and used a survey of 21 autosomal microsatellite loci to estimate heterozygosity for each female. We controlled for phenotypic plasticity and found that both clutch and egg size showed significant positive correlations with heterozygosity. We found no evidence that heterozygosity influenced the slope of individual reaction norms. Further analysis suggested that clutch size was affected by heterozygosity across the genome, but egg size had more complex relationships, with evidence favouring the influence of multiple loci. Given the apparent lack of inbreeding and large population size, our results suggest associative overdominance as the likely mechanism for the impact of heterozygosity, but also created a puzzle about the process producing associations between neutral markers and the genes affecting clutch size or egg size. One possible explanation is a long-term residual effect of the historical bottleneck that occurred when house sparrows were introduced into North America. The existence of heterozygosity-fitness correlations in a population with considerable phenotypic plasticity and little inbreeding implies that the effects of heterozygosity may be more significant than previously thought. © 2011 Blackwell Publishing Ltd.

  19. Quadrature formulas for Fourier coefficients

    KAUST Repository

    Bojanov, Borislav

    2009-09-01

    We consider quadrature formulas of high degree of precision for the computation of the Fourier coefficients in expansions of functions with respect to a system of orthogonal polynomials. In particular, we show the uniqueness of a multiple node formula for the Fourier-Tchebycheff coefficients given by Micchelli and Sharma and construct new Gaussian formulas for the Fourier coefficients of a function, based on the values of the function and its derivatives. © 2009 Elsevier B.V. All rights reserved.

  20. Measuring of heat transfer coefficient

    DEFF Research Database (Denmark)

    Henningsen, Poul; Lindegren, Maria

    Subtask 3.4 Measuring of heat transfer coefficient Subtask 3.4.1 Design and setting up of tests to measure heat transfer coefficient Objective: Complementary testing methods together with the relevant experimental equipment are to be designed by the two partners involved in order to measure...... the heat transfer coefficient for a wide range of interface conditions in hot and warm forging processes. Subtask 3.4.2 Measurement of heat transfer coefficient The objective of subtask 3.4.2 is to determine heat transfer values for different interface conditions reflecting those typically operating in hot...

  1. Mating animals by minimising the covariance between ancestral contributions generates less inbreeding without compromising genetic gain in breeding schemes with truncation selection

    DEFF Research Database (Denmark)

    Henryon, M; Berg, P; Sørensen, A C

    2009-01-01

    We reasoned that mating animals by minimising the covariance between ancestral contributions (MCAC mating) will generate less inbreeding and at least as much genetic gain as minimum-coancestry mating in breeding schemes where the animals are truncation-selected. We tested this hypothesis by stoch......We reasoned that mating animals by minimising the covariance between ancestral contributions (MCAC mating) will generate less inbreeding and at least as much genetic gain as minimum-coancestry mating in breeding schemes where the animals are truncation-selected. We tested this hypothesis...

  2. Sabine absorption coefficients to random incidence absorption coefficients

    DEFF Research Database (Denmark)

    Jeong, Cheol-Ho

    2014-01-01

    into random incidence absorption coefficients for porous absorbers are investigated. Two optimization-based conversion methods are suggested: the surface impedance estimation for locally reacting absorbers and the flow resistivity estimation for extendedly reacting absorbers. The suggested conversion methods...

  3. Niveles y efectos de la consanguinidad en variables de comportamiento durante la tienta y la lidia en dos ganaderías de reses bravas de Colombia Levels and effects of inbreeding on performance traits during tempt and fight from two fighting bull farms in Colombia

    Directory of Open Access Journals (Sweden)

    David Calero Quintero

    2010-04-01

    Full Text Available En el estudio se estimaron los niveles y las tendencias de la consanguinidad en variables de comportamiento durante la tienta y la lidia en dos ganaderías colombianas de reses bravas: Ernesto González Caicedo (EGC - Popayán, Cauca, encaste Santacoloma; y Guachicono (GUA - Bolívar, Cauca, Colombia, encaste Parladé. Se analizaron los pedigríes de 2.094 animales EGC nacidos entre 1918 y 2007 y 963 GUA, nacidos entre 1928 y 2005. Los coeficientes de consanguinidad de los bovinos se obtuvieron usando el Proc Inbreed del programa SAS v. 9.1.3. Se estudiaron además de las notas del ganadero, las variables propias y comunes a las faenas de tienta y de lidia. Los promedios y las desviaciones estándar de la consanguinidad en EGC y GUA fueron 4.9±6.6 y 4.2±4.2% para todos los animales, 4.5±5.8 y 6.0±3.4% para la última época estudiada, y 10.6±5.8 y 6.5±3.5% considerando sólo los consanguíneos. Se encontraron efectos positivos en las variables responsables de ‘toreabilidad’ y estilo, y depresivos en la fuerza de los animales. La consanguinidad actual en ambas ganaderías es mediana, sin embargo debe diseñarse un plan de apareamiento.This study was carried out to estimate levels and trends of the inbreeding on behavior variables during the tempt and fight from two fighting farms: Ernesto González Caicedo (EGC and Guachicono (GUA with strains Santacoloma, and Parladé respectively, located on Popayán and Bolívar, municipalities of the Cauca Department, Colombia. The pedigrees of 2094 EGC animals born between 1918 and 2007, and 963 GUA animals born between 1928 and 2005 were analyzed. Inbreeding coefficients of the cattle were obtained using PROC INBREED from the software SAS v. 9.1.3. In addition to the breeder’s notes the own variables, dealing and common to the tempt and fight task were studied. The average and standard deviations of the blood relationship during the total and the last time studied for the cattle raising EGC and

  4. Kuznetsov equation with variable coefficients

    Indian Academy of Sciences (India)

    like solutions of the PDE in (2+1) dimension with variable coefficients. ... Shivamoggi [12] gives only four polynomial conservation laws of the ZK equation ..... [3] P J Olver, Application of Lie group to differential equation (Springer, New York,.

  5. Fuel Temperature Coefficient of Reactivity

    Energy Technology Data Exchange (ETDEWEB)

    Loewe, W.E.

    2001-07-31

    A method for measuring the fuel temperature coefficient of reactivity in a heterogeneous nuclear reactor is presented. The method, which is used during normal operation, requires that calibrated control rods be oscillated in a special way at a high reactor power level. The value of the fuel temperature coefficient of reactivity is found from the measured flux responses to these oscillations. Application of the method in a Savannah River reactor charged with natural uranium is discussed.

  6. Benefits of group living include increased feeding efficiency and lower mass loss during desiccation in the social and inbreeding spider Stegodyphus dumicola.

    Directory of Open Access Journals (Sweden)

    Bram eVanthournout

    2016-02-01

    Full Text Available Group living carries a price: it inherently entails increased competition for resources and reproduction, and may also be associated with mating among relatives, which carries costs of inbreeding. Nonetheless, group living and sociality is found in many animals, and understanding the direct and indirect benefits of cooperation that override the inherent costs remains a challenge in evolutionary ecology. Individuals in groups may benefit from more efficient management of energy or water reserves, for example in the form of reduced water or heat loss from groups of animals huddling, or through reduced energy demands afforded by shared participation in tasks. We investigated the putative benefits of group living in the permanently social spider Stegodyphus dumicola by comparing the effect of group size on standard metabolic rate, lipid/protein content as a body condition measure, feeding efficiency, per capita web investment and weight/water loss and survival during desiccation. Because energetic expenditure is temperature sensitive, some assays were performed under varying temperature conditions. We found that feeding efficiency increased with group size, and the rate of weight loss was higher in solitary individuals than in animals in groups of various sizes during desiccation. Interestingly, this was not translated into differences in survival or in standard metabolic rate. We did not detect any group size effects for other parameters, and group size effects did not co-vary with experimental temperature in a predictive manner. Both feeding efficiency and mass loss during desiccation are relevant ecological factors as the former results in lowered predator exposure time, and the latter benefits social spiders which occupy arid, hot environments.

  7. Clustering Coefficients for Correlation Networks

    Directory of Open Access Journals (Sweden)

    Naoki Masuda

    2018-03-01

    Full Text Available Graph theory is a useful tool for deciphering structural and functional networks of the brain on various spatial and temporal scales. The clustering coefficient quantifies the abundance of connected triangles in a network and is a major descriptive statistics of networks. For example, it finds an application in the assessment of small-worldness of brain networks, which is affected by attentional and cognitive conditions, age, psychiatric disorders and so forth. However, it remains unclear how the clustering coefficient should be measured in a correlation-based network, which is among major representations of brain networks. In the present article, we propose clustering coefficients tailored to correlation matrices. The key idea is to use three-way partial correlation or partial mutual information to measure the strength of the association between the two neighboring nodes of a focal node relative to the amount of pseudo-correlation expected from indirect paths between the nodes. Our method avoids the difficulties of previous applications of clustering coefficient (and other measures in defining correlational networks, i.e., thresholding on the correlation value, discarding of negative correlation values, the pseudo-correlation problem and full partial correlation matrices whose estimation is computationally difficult. For proof of concept, we apply the proposed clustering coefficient measures to functional magnetic resonance imaging data obtained from healthy participants of various ages and compare them with conventional clustering coefficients. We show that the clustering coefficients decline with the age. The proposed clustering coefficients are more strongly correlated with age than the conventional ones are. We also show that the local variants of the proposed clustering coefficients (i.e., abundance of triangles around a focal node are useful in characterizing individual nodes. In contrast, the conventional local clustering coefficients

  8. Non-constant retardation coefficient

    International Nuclear Information System (INIS)

    Wang Zhiming; Gu Zhijie; Yang Yue'e; Li Shushen

    2004-12-01

    Retardation coefficient is one of the important parameters used in transport models describing radionuclide migration in geological media and usually regarded as a constant in the models. The objectives of the work are to understand: (1) Whether the retardation coefficient, R d , is a constant? (2) How much effect is R d on calculated consequence if R d is not constant? (3) Is the retardation coefficient derived from distribution coefficient, k d , according to conventional equation suitable for safety assessment? The objectives are achieved through test and analysis of the test results on radionuclide migration in unsaturated loess. It can be seen from the results that retardation coefficient, R d , of 85 Sr is not constant and increases with water content, θ, under unsaturated condition. R d , of 85 Sr derived from k d according to conventional equation can not be used for safety assessment. R d , used for safety assessment should be directly measured, rather than derived from k d . It is shown from calculation that the effect of R d on calculated consequence is very considerable. (authors)

  9. Inbreeding depression increases susceptibility to bovine tuberculosis in lions: an experimental test using an inbred-outbred contrast through translocation.

    Science.gov (United States)

    Trinkel, Martina; Cooper, Dave; Packer, Craig; Slotow, Rob

    2011-07-01

    Disease can dramatically influence the dynamics of endangered wildlife populations, especially when they are small and isolated, with increased risk of inbreeding. In Hluhluwe-iMfolozi Park (HiP), a small, enclosed reserve in South Africa, a large lion (Panthera leo) population arose from a small founder group in the 1960s and started showing conspicuous signs of inbreeding. To restore the health status of the HiP lion population, outbred lions were translocated into the existing population. In this study, we determined the susceptibility to bovine tuberculosis (bTB), and the prevalence of antibody to feline viruses of native lions, and compared the findings with those from translocated outbred lions and their offspring. Antibodies to feline herpesvirus, feline calicivirus, feline parvovirus, and feline coronavirus were present in the lion population, but there was no significant difference in antibody prevalence between native and translocated lions and their offspring, and these feline viruses did not appear to have an effect on the clinical health of HiP lions. However, feline immunodeficiency virus (FIV), which was previously absent from HiP, appears to have been introduced into the lion population through translocation. Within 7 yr, the prevalence of antibody to FIV increased up to 42%. Bovine tuberculosis posed a major threat to the inbred native lion population, but not to translocated lions and their offspring. More than 30% of the native lion population died from bTB or malnutrition compared with lions and their offspring. We have demonstrated that management of population genetics through supplementation can successfully combat a disease that threatens population persistence. However, great care must be taken not to introduce new diseases into populations through translocation.

  10. Coefficient estimates of negative powers and inverse coefficients for ...

    Indian Academy of Sciences (India)

    1 an(−λ, f )zn for z ∈ D. (1.4). One of the well-known extremal problems in the theory of univalent functions is to esti- mate the modulus of the Taylor coefficients an(−λ, f ) given by (1.4). This problem has been extensively studied in the literature ...

  11. Harmonic functions with varying coefficients

    Directory of Open Access Journals (Sweden)

    Jacek Dziok

    2016-05-01

    Full Text Available Abstract Complex-valued harmonic functions that are univalent and sense preserving in the open unit disk can be written in the form f = h + g ‾ $f=h+\\overline{g}$ , where h and g are analytic. In this paper we investigate some classes of univalent harmonic functions with varying coefficients related to Janowski functions. By using the extreme points theory we obtain necessary and sufficient convolution conditions, coefficients estimates, distortion theorems, and integral mean inequalities for these classes of functions. The radii of starlikeness and convexity for these classes are also determined.

  12. Integer Solutions of Binomial Coefficients

    Science.gov (United States)

    Gilbertson, Nicholas J.

    2016-01-01

    A good formula is like a good story, rich in description, powerful in communication, and eye-opening to readers. The formula presented in this article for determining the coefficients of the binomial expansion of (x + y)n is one such "good read." The beauty of this formula is in its simplicity--both describing a quantitative situation…

  13. Effective Viscosity Coefficient of Nanosuspensions

    Science.gov (United States)

    Rudyak, V. Ya.; Belkin, A. A.; Egorov, V. V.

    2008-12-01

    Systematic calculations of the effective viscosity coefficient of nanosuspensions have been performed using the molecular dynamics method. It is established that the viscosity of a nanosuspension depends not only on the volume concentration of the nanoparticles but also on their mass and diameter. Differences from Einstein's relation are found even for nanosuspensions with a low particle concentration.

  14. Irrational "Coefficients" in Renaissance Algebra.

    Science.gov (United States)

    Oaks, Jeffrey A

    2017-06-01

    Argument From the time of al-Khwārizmī in the ninth century to the beginning of the sixteenth century algebraists did not allow irrational numbers to serve as coefficients. To multiply by x, for instance, the result was expressed as the rhetorical equivalent of . The reason for this practice has to do with the premodern concept of a monomial. The coefficient, or "number," of a term was thought of as how many of that term are present, and not as the scalar multiple that we work with today. Then, in sixteenth-century Europe, a few algebraists began to allow for irrational coefficients in their notation. Christoff Rudolff (1525) was the first to admit them in special cases, and subsequently they appear more liberally in Cardano (1539), Scheubel (1550), Bombelli (1572), and others, though most algebraists continued to ban them. We survey this development by examining the texts that show irrational coefficients and those that argue against them. We show that the debate took place entirely in the conceptual context of premodern, "cossic" algebra, and persisted in the sixteenth century independent of the development of the new algebra of Viète, Decartes, and Fermat. This was a formal innovation violating prevailing concepts that we propose could only be introduced because of the growing autonomy of notation from rhetorical text.

  15. Depression by inbreeding after four sucessive self-pollination squash generations Depressão por endogamia após quatro gerações sucessivas de autopolinização em abóbora

    Directory of Open Access Journals (Sweden)

    Antonio Ismael Inácio Cardoso

    2004-04-01

    Full Text Available The strategy for breeding F1 hybrid squash is to develop parental lines through self-pollination. However, it increases plant mean homozygosis, which is not the natural genetic state of a cross-pollinated species, and can cause "inbreeding depression". The objective of this work was to evaluate this depression with sucessive generations of self-pollination (without selection in Cucurbita moschata, cv. Piramoita. Populations were obtained from lines with one to four generations of self-pollination (obtained by the SSD method, from the original cv. Piramoita (population S0. Randomized blocks were used with five treatments (different generations of self-pollination - S0 to S4, six replicates and five plants per plot. Regression analysis was made by the Wright inbreeding coefficient (F to measure the homozygosis level effect on vigor loss. There was a linear reduction of mean weight and fruit length, seed production (number and weight per fruit with the increase of the homozygosis level; however inbreeding did not affect seed quality (weight of 100 seeds and germination.A estratégia utilizada no melhoramento genético visando híbridos F1 em abóbora é a obtenção de linhagens por autopolinização. Entretanto, a autopolinização aumenta a homozigose média das plantas, que não é a condição genética natural de espécies alógamas, e pode causar a "depressão por endogamia". Este trabalho teve como objetivo verificar se existe depressão por endogamia com sucessivas gerações de autofecundação (sem seleção em abóbora cultivar Piramoita. Foram obtidas populações a partir da mistura de linhagens com uma a quatro gerações de autofecundação (obtidas pelo método SSD, a partir da população original 'Piramoita' (S0. O delineamento experimental utilizado foi em blocos ao acaso com cinco tratamentos (diferentes gerações de autofecundação - S0 a S4, seis repetições e cinco plantas por parcela. Realizou-se análise de regress

  16. Transport coefficients in copper vapor arc plasmas

    International Nuclear Information System (INIS)

    Rahal, A.M.; Rahhaoui, B.; Vacquie, S.

    1985-01-01

    The presence of copper vapors modifies the properties of arc discharges. The paper deals with a region not investigated earlier, where in the core of the positive column of very short or high current arcs there is a high copper concentration. At these values the relative losses take a greater part in the energy balance. Using the charged-charged collision integrals, the transport coefficients (axial temperature, thermal and electric conductivity, viscosity) of the plasma with higher copper vapor concentration are calculated as the function of the arc current intensity. (D.Gy.)

  17. Extinction Coefficient of Gold Nanostars

    OpenAIRE

    de Puig, Helena; Tam, Justina O.; Yen, Chun-Wan; Gehrke, Lee; Hamad-Schifferli, Kimberly

    2015-01-01

    Gold nanostars (NStars) are highly attractive for biological applications due to their surface chemistry, facile synthesis and optical properties. Here, we synthesize NStars in HEPES buffer at different HEPES/Au ratios, producing NStars of different sizes and shapes, and therefore varying optical properties. We measure the extinction coefficient of the synthesized NStars at their maximum surface plasmon resonances (SPR), which range from 5.7 × 108 to 26.8 × 108 M−1cm−1. Measured values correl...

  18. Influence of effective stress coefficient on mechanical failure of chalk

    DEFF Research Database (Denmark)

    Alam, Mohammad Monzurul; Fabricius, Ida Lykke; Hjuler, M.L.

    2012-01-01

    and vice versa. However, as the effective stress working on the rock decreases with increased effective stress coefficient, the reduction of elastic region will have less effect on pore collapse strength if we consider the change in the effective stress coefficient. This finding will help estimate a more......The Effective stress coefficient is a measure of how chalk grains are connected with each other. The stiffness of chalk may decrease if the amount of contact cements between the grains decreases, which may lead to an increase of the effective stress coefficient. We performed CO2 injection in chalk......, as this process could affect the grain contact cement. If this happens, the effective stress at the grain contacts in a reservoir will change according to the effective stress principle of Biot. In a p′-q space for failure analysis, we observed that a higher effective stress coefficient reduces the elastic region...

  19. Higher education

    OpenAIRE

    Wolter, Andrä

    2009-01-01

    During the last five years higher education research in Germany seems to be in a significant upturn. This is a side effect partly of the obvious boom of empirical educational research in general and partly of the reform movement that has affected the German higher education system since middle of the 1990s. The demand for data in the field of higher education will increase considerably in future. The available data infrastructure for higher education research in Germany consists of two comple...

  20. Influence of effective stress coefficient on mechanical failure of chalk

    DEFF Research Database (Denmark)

    Alam, Mohammad Monzurul; Fabricius, Ida Lykke; Hjuler, M.L.

    2012-01-01

    , as this process could affect the grain contact cement. If this happens, the effective stress at the grain contacts in a reservoir will change according to the effective stress principle of Biot. In a p′-q space for failure analysis, we observed that a higher effective stress coefficient reduces the elastic region...... and vice versa. However, as the effective stress working on the rock decreases with increased effective stress coefficient, the reduction of elastic region will have less effect on pore collapse strength if we consider the change in the effective stress coefficient. This finding will help estimate a more...

  1. Study of transport coefficients of nanodiamond nanofluids

    Science.gov (United States)

    Pryazhnikov, M. I.; Minakov, A. V.; Guzei, D. V.

    2017-09-01

    Experimental data on the thermal conductivity coefficient and viscosity coefficient of nanodiamond nanofluids are presented. Distilled water and ethylene glycol were used as the base fluid. Dependences of transport coefficients on concentration are obtained. It was shown that the thermal conductivity coefficient increases with increasing nanodiamonds concentration. It was shown that base fluids properties and nanodiamonds concentration affect on the rheology of nanofluids.

  2. Kinship, inbreeding and fine-scale spatial structure influence gut microbiota in a hindgut-fermenting tortoise.

    Science.gov (United States)

    Yuan, Michael L; Dean, Samantha H; Longo, Ana V; Rothermel, Betsie B; Tuberville, Tracey D; Zamudio, Kelly R

    2015-05-01

    Herbivorous vertebrates rely on complex communities of mutualistic gut bacteria to facilitate the digestion of celluloses and hemicelluloses. Gut microbes are often convergent based on diet and gut morphology across a phylogenetically diverse group of mammals. However, little is known about microbial communities of herbivorous hindgut-fermenting reptiles. Here, we investigate how factors at the individual level might constrain the composition of gut microbes in an obligate herbivorous reptile. Using multiplexed 16S rRNA gene sequencing, we characterized the faecal microbial community of a population of gopher tortoises (Gopherus polyphemus) and examined how age, genetic diversity, spatial structure and kinship influence differences among individuals. We recovered phylotypes associated with known cellulolytic function, including candidate phylum Termite Group 3, suggesting their importance for gopher tortoise digestion. Although host genetic structure did not explain variation in microbial composition and community structure, we found that fine-scale spatial structure, inbreeding, degree of relatedness and possibly ontogeny shaped patterns of diversity in faecal microbiomes of gopher tortoises. Our findings corroborate widespread convergence of faecal-associated microbes based on gut morphology and diet and demonstrate the role of spatial and demographic structure in driving differentiation of gut microbiota in natural populations. © 2015 John Wiley & Sons Ltd.

  3. Inbreeding and adaptive plasticity: an experimental analysis on predator-induced responses in the water flea Daphnia

    Science.gov (United States)

    Swillen, Ine; Vanoverbeke, Joost; De Meester, Luc

    2015-01-01

    Several studies have emphasized that inbreeding depression (ID) is enhanced under stressful conditions. Additionally, one might imagine a loss of adaptively plastic responses which may further contribute to a reduction in fitness under environmental stress. Here, we quantified ID in inbred families of the cyclical parthenogen Daphnia magna in the absence and presence of fish predation risk. We test whether predator stress affects the degree of ID and if inbred families have a reduced capacity to respond to predator stress by adaptive phenotypic plasticity. We obtained two inbred families through clonal selfing within clones isolated from a fish pond. After mild purging under standardized conditions, we compared life history traits and adaptive plasticity between inbred and outbred lineages (directly hatched from the natural dormant egg bank of the same pond). Initial purging of lineages under standardized conditions differed among inbred families and exceeded that in outbreds. The least purged inbred family exhibited strong ID for most life history traits. Predator-induced stress hardly affected the severity of ID, but the degree to which the capacity for adaptive phenotypic plasticity was retained varied strongly among the inbred families. The least purged family overall lacked the capacity for adaptive phenotypic plasticity, whereas the family that suffered only mild purging exhibited a potential for adaptive plasticity that was comparable to the outbred population. We thus found that inbred offspring may retain the capacity to respond to the presence of fish by adaptive phenotypic plasticity, but this strongly depends on the parental clone engaging in selfing. PMID:26257883

  4. Measurements of thermal accommodation coefficients.

    Energy Technology Data Exchange (ETDEWEB)

    Rader, Daniel John; Castaneda, Jaime N.; Torczynski, John Robert; Grasser, Thomas W.; Trott, Wayne Merle

    2005-10-01

    A previously-developed experimental facility has been used to determine gas-surface thermal accommodation coefficients from the pressure dependence of the heat flux between parallel plates of similar material but different surface finish. Heat flux between the plates is inferred from measurements of temperature drop between the plate surface and an adjacent temperature-controlled water bath. Thermal accommodation measurements were determined from the pressure dependence of the heat flux for a fixed plate separation. Measurements of argon and nitrogen in contact with standard machined (lathed) or polished 304 stainless steel plates are indistinguishable within experimental uncertainty. Thus, the accommodation coefficient of 304 stainless steel with nitrogen and argon is estimated to be 0.80 {+-} 0.02 and 0.87 {+-} 0.02, respectively, independent of the surface roughness within the range likely to be encountered in engineering practice. Measurements of the accommodation of helium showed a slight variation with 304 stainless steel surface roughness: 0.36 {+-} 0.02 for a standard machine finish and 0.40 {+-} 0.02 for a polished finish. Planned tests with carbon-nanotube-coated plates will be performed when 304 stainless-steel blanks have been successfully coated.

  5. Systematic Risk on Istanbul Stock Exchange: Traditional Beta Coefficient Versus Downside Beta Coefficient

    Directory of Open Access Journals (Sweden)

    Gülfen TUNA

    2013-03-01

    Full Text Available The aim of this study is to test the validity of Downside Capital Asset Pricing Model (D-CAPM on the ISE. At the same time, the explanatory power of CAPM's traditional beta and D-CAPM's downside beta on the changes in the average return values are examined comparatively. In this context, the monthly data for seventy three stocks that are continuously traded on the ISE for the period 1991-2009 is used. Regression analysis is applied in this study. The research results have shown that D-CAPM is valid on the ISE. In addition, it is obtained that the power of downside beta coefficient is higher than traditional beta coefficient on explaining the return changes. Therefore, it can be said that the downside beta is superior to traditional beta in the ISE for chosen period.

  6. Extinction Coefficient of Gold Nanostars.

    Science.gov (United States)

    de Puig, Helena; Tam, Justina O; Yen, Chun-Wan; Gehrke, Lee; Hamad-Schifferli, Kimberly

    2015-07-30

    Gold nanostars (NStars) are highly attractive for biological applications due to their surface chemistry, facile synthesis and optical properties. Here, we synthesize NStars in HEPES buffer at different HEPES/Au ratios, producing NStars of different sizes and shapes, and therefore varying optical properties. We measure the extinction coefficient of the synthesized NStars at their maximum surface plasmon resonances (SPR), which range from 5.7 × 10 8 to 26.8 × 10 8 M -1 cm -1 . Measured values correlate with those obtained from theoretical models of the NStars using the discrete dipole approximation (DDA), which we use to simulate the extinction spectra of the nanostars. Finally, because NStars are typically used in biological applications, we conjugate DNA and antibodies to the NStars and calculate the footprint of the bound biomolecules.

  7. Kerr scattering coefficients via isomonodromy

    Energy Technology Data Exchange (ETDEWEB)

    Cunha, Bruno Carneiro da [Departamento de Física, Universidade Federal de Pernambuco,50670-901, Recife, Pernambuco (Brazil); Novaes, Fábio [International Institute of Physics, Federal University of Rio Grande do Norte,Av. Odilon Gomes de Lima 1722, Capim Macio, Natal-RN 59078-400 (Brazil)

    2015-11-23

    We study the scattering of a massless scalar field in a generic Kerr background. Using a particular gauge choice based on the current conservation of the radial equation, we give a generic formula for the scattering coefficient in terms of the composite monodromy parameter σ between the inner and the outer horizons. Using the isomonodromy flow, we calculate σ exactly in terms of the Painlevé V τ-function. We also show that the eigenvalue problem for the angular equation (spheroidal harmonics) can be calculated using the same techniques. We use recent developments relating the Painlevé V τ-function to Liouville irregular conformal blocks to claim that this scattering problem is solved in the combinatorial sense, with known expressions for the τ-function near the critical points.

  8. Sorption Coefficients for Iodine, Silver, and Cesium on Dust Particles

    International Nuclear Information System (INIS)

    Stempniewicz, M.M.; Goede, P.

    2014-01-01

    This paper describes the work performed to find relevant experimental data and find the sorption coefficients that represent well the available data for cesium, iodine, and silver on dust particles. The purpose of this work is to generate a set of coefficients that may be recommended for the computer code users. The work was performed using the computer code SPECTRA. Calculations were performed for the following data: • I-131 on AVR dust; • Ag-110m on AVR dust; • Cs-13 and Cs-137 on AVR dust. Available data was matched using the SPECTRA Sorption Model. S = A(T) · C V -B(T) · C d . The results are summarized as follows: • The available data can be correlated. The data scatter is about 4 orders of magnitude. Therefore the coefficients of the Langmuir isotherms vary by 4 orders of magnitude. • Sorption rates are higher at low temperatures and lower at high temperatures. This tendency has been observed in the data compiled at Oak Ridge. It is therefore surmised that the highest value of the sorption coefficients are appropriate for the low temperatures and the lowest value of the sorption coefficients are appropriate for the high temperatures. The recommended sorption coefficients are presented in this paper. • The present set of coefficients is very rough and should be a subject for future verification against experimental data. (author)

  9. Factorization of Transport Coefficients in Macroporous Media

    DEFF Research Database (Denmark)

    Shapiro, Alexander; Stenby, Erling Halfdan

    2000-01-01

    We prove the fundamental theorem about factorization of the phenomenological coefficients for transport in macroporous media. By factorization we mean the representation of the transport coefficients as products of geometric parameters of the porous medium and the parameters characteristic...

  10. Challenging the inbreeding hypothesis in a eusocial mammal: population genetics of the naked mole-rat, Heterocephalus glaber.

    Science.gov (United States)

    Ingram, Colleen M; Troendle, Nicholas J; Gill, Clare A; Braude, Stanton; Honeycutt, Rodney L

    2015-10-01

    The role of genetic relatedness in the evolution of eusociality has been the topic of much debate, especially when contrasting eusocial insects with vertebrates displaying reproductive altruism. The naked mole-rat, Heterocephalus glaber, was the first described eusocial mammal. Although this discovery was based on an ecological constraints model of eusocial evolution, early genetic studies reported high levels of relatedness in naked mole-rats, providing a compelling argument that low dispersal rates and consanguineous mating (inbreeding as a mating system) are the driving forces for the evolution of this eusocial species. One caveat to accepting this long-held view is that the original genetic studies were based on limited sampling from the species' geographic distribution. A growing body of evidence supports a contrary view, with the original samples not representative of the species-rather reflecting a single founder event, establishing a small population south of the Athi River. Our study is the first to address these competing hypotheses by examining patterns of molecular variation in colonies sampled from north and south of the Athi and Tana rivers, which based on our results, serve to isolate genetically distinct populations of naked mole-rats. Although colonies south of the Athi River share a single mtDNA haplotype and are fixed at most microsatellite loci, populations north of the Athi River are considerably more variable. Our findings support the position that the low variation observed in naked mole-rat populations south of the Athi River reflects a founder event, rather than a consequence of this species' unusual mating system. © 2015 John Wiley & Sons Ltd.

  11. Nuclear genetic diversity in human lice (Pediculus humanus reveals continental differences and high inbreeding among worldwide populations.

    Directory of Open Access Journals (Sweden)

    Marina S Ascunce

    Full Text Available Understanding the evolution of parasites is important to both basic and applied evolutionary biology. Knowledge of the genetic structure of parasite populations is critical for our ability to predict how an infection can spread through a host population and for the design of effective control methods. However, very little is known about the genetic structure of most human parasites, including the human louse (Pediculus humanus. This species is composed of two ecotypes: the head louse (Pediculus humanus capitis De Geer, and the clothing (body louse (Pediculus humanus humanus Linnaeus. Hundreds of millions of head louse infestations affect children every year, and this number is on the rise, in part because of increased resistance to insecticides. Clothing lice affect mostly homeless and refugee-camp populations and although they are less prevalent than head lice, the medical consequences are more severe because they vector deadly bacterial pathogens. In this study we present the first assessment of the genetic structure of human louse populations by analyzing the nuclear genetic variation at 15 newly developed microsatellite loci in 93 human lice from 11 sites in four world regions. Both ecotypes showed heterozygote deficits relative to Hardy-Weinberg equilibrium and high inbreeding values, an expected pattern given their parasitic life history. Bayesian clustering analyses assigned lice to four distinct genetic clusters that were geographically structured. The low levels of gene flow among louse populations suggested that the evolution of insecticide resistance in lice would most likely be affected by local selection pressures, underscoring the importance of tailoring control strategies to population-specific genetic makeup and evolutionary history. Our panel of microsatellite markers provides powerful data to investigate not only ecological and evolutionary processes in lice, but also those in their human hosts because of the long

  12. Inferring Individual Inbreeding and Demographic History from Segments of Identity by Descent inFicedulaFlycatcher Genome Sequences.

    Science.gov (United States)

    Kardos, Marty; Qvarnström, Anna; Ellegren, Hans

    2017-03-01

    Individual inbreeding and historical demography can be estimated by analyzing runs of homozygosity (ROH), which are indicative of chromosomal segments of identity by descent (IBD). Such analyses have so far been rare in natural populations due to limited genomic resources. We analyzed ROH in whole genome sequences from 287 Ficedula flycatchers representing four species, with the objectives of evaluating the causes of genome-wide variation in the abundance of ROH and inferring historical demography. ROH were clearly more abundant in genomic regions with low recombination rate. However, this pattern was substantially weaker when ROH were mapped using genetic rather than physical single nucleotide polymorphism (SNP) coordinates in the genome. Empirical results and simulations suggest that high ROH abundance in regions of low recombination was partly caused by increased power to detect the very long IBD segments typical of regions with a low recombination rate. Simulations also showed that hard selective sweeps (but not soft sweeps or background selection) likely contributed to variation in the abundance of ROH across the genome. Comparisons of the abundance of ROH among several study populations indicated that the Spanish pied flycatcher population had the smallest historical effective population size ( N e ) for this species, and that a putatively recently founded island (Baltic) population had the smallest historical N e among the collared flycatchers. Analysis of pairwise IBD in Baltic collared flycatchers indicated that this population was founded <60 generations ago. This study provides a rare genomic glimpse into demographic history and the mechanisms underlying the genome-wide distribution of ROH. Copyright © 2017 by the Genetics Society of America.

  13. Symmetry chains and adaptation coefficients

    International Nuclear Information System (INIS)

    Fritzer, H.P.; Gruber, B.

    1985-01-01

    Given a symmetry chain of physical significance it becomes necessary to obtain states which transform properly with respect to the symmetries of the chain. In this article we describe a method which permits us to calculate symmetry-adapted quantum states with relative ease. The coefficients for the symmetry-adapted linear combinations are obtained, in numerical form, in terms of the original states of the system and can thus be represented in the form of numerical tables. In addition, one also obtains automatically the matrix elements for the operators of the symmetry groups which are involved, and thus for any physical operator which can be expressed either as an element of the algebra or of the enveloping algebra. The method is well suited for computers once the physically relevant symmetry chain, or chains, have been defined. While the method to be described is generally applicable to any physical system for which semisimple Lie algebras play a role we choose here a familiar example in order to illustrate the method and to illuminate its simplicity. We choose the nuclear shell model for the case of two nucleons with orbital angular momentum l = 1. While the states of the entire shell transform like the smallest spin representation of SO(25) we restrict our attention to its subgroup SU(6) x SU(2)/sub T/. We determine the symmetry chains which lead to total angular momentum SU(2)/sub J/ and obtain the symmetry-adapted states for these chains

  14. Standards for Standardized Logistic Regression Coefficients

    Science.gov (United States)

    Menard, Scott

    2011-01-01

    Standardized coefficients in logistic regression analysis have the same utility as standardized coefficients in linear regression analysis. Although there has been no consensus on the best way to construct standardized logistic regression coefficients, there is now sufficient evidence to suggest a single best approach to the construction of a…

  15. Anomalous Seebeck coefficient in boron carbides

    International Nuclear Information System (INIS)

    Aselage, T.L.; Emin, D.; Wood, C.; Mackinnon, I.D.R.; Howard, I.A.

    1987-01-01

    Boron carbides exhibit an anomalously large Seebeck coefficient with a temperature coefficient that is characteristic of polaronic hopping between inequivalent sites. The inequivalence in the sites is associated with disorder in the solid. The temperature dependence of the Seebeck coefficient for materials prepared by different techniques provides insight into the nature of the disorder

  16. Coefficient rings of formal group laws

    International Nuclear Information System (INIS)

    Buchstaber, V M; Ustinov, A V

    2015-01-01

    We describe the coefficient rings of universal formal group laws which arise in algebraic geometry, algebraic topology and their application to mathematical physics. We also describe the homomorphisms of these coefficient rings coming from reductions of one formal group law to another. The proofs are based on the number-theoretic properties of binomial coefficients. Bibliography: 37 titles

  17. Soccer Ball Lift Coefficients via Trajectory Analysis

    Science.gov (United States)

    Goff, John Eric; Carre, Matt J.

    2010-01-01

    We performed experiments in which a soccer ball was launched from a machine while two high-speed cameras recorded portions of the trajectory. Using the trajectory data and published drag coefficients, we extracted lift coefficients for a soccer ball. We determined lift coefficients for a wide range of spin parameters, including several spin…

  18. Diffusion coefficient in photon diffusion theory

    NARCIS (Netherlands)

    Graaff, R; Ten Bosch, JJ

    2000-01-01

    The choice of the diffusion coefficient to be used in photon diffusion theory has been a subject of discussion in recent publications on tissue optics. We compared several diffusion coefficients with the apparent diffusion coefficient from the more fundamental transport theory, D-app. Application to

  19. The compounding effects of high pollen limitation, selfing rates and inbreeding depression leave a New Zealand tree with few viable offspring.

    Science.gov (United States)

    Van Etten, Megan L; Tate, Jennifer A; Anderson, Sandra H; Kelly, Dave; Ladley, Jenny J; Merrett, Merilyn F; Peterson, Paul G; Robertson, Alastair W

    2015-10-01

    Interactions between species are especially sensitive to environmental changes. The interaction between plants and pollinators is of particular interest given the potential current global decline in pollinators. Reduced pollinator services can be compensated for in some plant species by self-pollination. However, if inbreeding depression is high, selfed progeny could die prior to reaching adulthood, leading to cryptic recruitment failure. To examine this scenario, pollinator abundance, pollen limitation, selfing rates and inbreeding depression were examined in 12 populations of varying disturbance levels in Sophora microphylla (Fabaceae), an endemic New Zealand tree species. High pollen limitation was found in all populations (average of 58 % reduction in seed production, nine populations), together with high selfing rates (61 % of offspring selfed, six populations) and high inbreeding depression (selfed offspring 86 % less fit, six populations). Pollen limitation was associated with lower visitation rates by the two endemic bird pollinators. The results suggest that for these populations, over half of the seeds produced are genetically doomed. This reduction in the fitness of progeny due to reduced pollinator service is probably important to population dynamics of other New Zealand species. More broadly, the results suggest that measures of seed production or seedling densities may be a gross overestimate of the effective offspring production. This could lead to cryptic recruitment failure, i.e. a decline in successful reproduction despite high progeny production. Given the global extent of pollinator declines, cryptic recruitment failure may be widespread. © The Author 2015. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  20. Seasonal cycle of inbreeding and recombination of the parasitic mite Varroa destructor in honeybee colonies and its implications for the selection of acaricide resistance.

    Science.gov (United States)

    Beaurepaire, Alexis L; Krieger, Klemens J; Moritz, Robin F A

    2017-06-01

    Varroa destructor is the most devastating parasite of the Western honeybee, Apis mellifera. In the light of the arm race opposing the host and its parasite, the population dynamics and genetic diversity of these organisms are key parameters. However, the life cycle of V. destructor is characterized by extreme inbreeding due to full sibling mating in the host brood cells. We here present an equation reflecting the evolution of inbreeding in such a clonal system, and compare our predictions with empirical data based on the analysis of seven microsatellite markers. This comparison revealed that the mites perform essentially incestuous mating in the beginning of the brood season. However, this pattern changes with the development of mite infestation. Despite the fact that the overall level of genetic diversity of the mites remained low through the season, multiple inbred lineages were identified in the mites we sampled in June. As a response to the decrease of brood availability and the increase of the parasite population in parallel in the colonies, these lineages recombined towards the end of the season as mites co-infest brood cells. Our results suggest that the ratio of the number of mite per brood cell in the colony determines the genetic structure of the populations of V. destructor. This intracolonial population dynamics has great relevance for the selection of acaricide resistance in V. destructor. If chemical treatments occur before the recombination phase, inbreeding will greatly enhance the fixation of resistance alleles at the colony level. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Energy coefficients for a propeller series

    DEFF Research Database (Denmark)

    Olsen, Anders Smærup

    2004-01-01

    The efficiency for a propeller is calculated by energy coefficients. These coefficients are related to four types of losses, i.e. the axial, the rotational, the frictional, and the finite blade number loss, and one gain, i.e. the axial gain. The energy coefficients are derived by use...... of the potential theory with the propeller modelled as an actuator disk. The efficiency based on the energy coefficients is calculated for a propeller series. The results show a good agreement between the efficiency based on the energy coefficients and the efficiency obtained by a vortex-lattice method....

  2. Index-free heat kernel coefficients

    Science.gov (United States)

    van de Ven, Anton E. M.

    1998-08-01

    Using index-free notation, we present the diagonal values 0264-9381/15/8/014/img1 of the first five heat kernel coefficients 0264-9381/15/8/014/img2 associated with a general Laplace-type operator on a compact Riemannian space without boundary. The fifth coefficient 0264-9381/15/8/014/img3 appears here for the first time. For the special case of a flat space, but with a gauge connection, the sixth coefficient is given too. Also provided are the leading terms for any coefficient, both in ascending and descending powers of the Yang-Mills and Riemann curvatures, to the same order as required for the fourth coefficient. These results are obtained by directly solving the relevant recursion relations, working in the Fock-Schwinger gauge and Riemann normal coordinates. Our procedure is thus non-covariant, but we show that for any coefficient the `gauged', respectively `curved', version is found from the corresponding `non-gauged', respectively `flat', coefficient by making some simple covariant substitutions. These substitutions being understood, the coefficients retain their `flat' form and size. In this sense the fifth and sixth coefficient have only 26 and 75 terms, respectively, allowing us to write them down. Using index-free notation also clarifies the general structure of the heat kernel coefficients. In particular, in flat space we find that from the fifth coefficient onward, certain scalars are absent. This may be relevant for the anomalies of quantum field theories in ten or more dimensions.

  3. Local Transfer Coefficient, Smooth Channel

    Directory of Open Access Journals (Sweden)

    R. T. Kukreja

    1998-01-01

    Full Text Available Naphthalene sublimation technique and the heat/mass transfer analogy are used to determine the detailed local heat/mass transfer distributions on the leading and trailing walls of a twopass square channel with smooth walls that rotates about a perpendicular axis. Since the variation of density is small in the flow through the channel, buoyancy effect is negligible. Results show that, in both the stationary and rotating channel cases, very large spanwise variations of the mass transfer exist in he turn and in the region immediately downstream of the turn in the second straight pass. In the first straight pass, the rotation-induced Coriolis forces reduce the mass transfer on the leading wall and increase the mass transfer on the trailing wall. In the turn, rotation significantly increases the mass transfer on the leading wall, especially in the upstream half of the turn. Rotation also increases the mass transfer on the trailing wall, more in the downstream half of the turn than in the upstream half of the turn. Immediately downstream of the turn, rotation causes the mass transfer to be much higher on the trailing wall near the downstream corner of the tip of the inner wall than on the opposite leading wall. The mass transfer in the second pass is higher on the leading wall than on the trailing wall. A slower flow causes higher mass transfer enhancement in the turn on both the leading and trailing walls.

  4. Reproducibility of The Random Incidence Absorption Coefficient Converted From the Sabine Absorption Coefficient

    DEFF Research Database (Denmark)

    Jeong, Cheol-Ho; Chang, Ji-ho

    2015-01-01

    Absorption coefficients measured in reverberation chambers, Sabine absorption coefficients, suffer from two major problems. Firstly, they sometimes exceed unity. Secondly, the reproducibility of the Sabine absorption coefficients is quite poor, meaning that the Sabine absorption coefficients vary...... resistivity optimization outperforms the surface impedance optimization in terms of the reproducibility....

  5. The Heat Transfer Coefficient of Recycled Concrete Bricks Combination with EPS Insulation Board Wall

    Directory of Open Access Journals (Sweden)

    Jianhua Li

    2015-01-01

    Full Text Available Four tectonic forms samples were conducted to test their heat transfer coefficients. By analyzing and comparing the test values and theoretical values of the heat transfer coefficient, a corrected-value calculation method for determining the heat transfer coefficient was proposed; the proposed method was proved to be reasonably correct. The results indicated that the recycled concrete brick wall heat transfer coefficient is higher than that of the clay brick wall, the heat transfer coefficient of recycled concrete brick wall could be effectively reduced when combined with the EPS insulation board, and the sandwich insulation type was better than that of external thermal insulation type.

  6. Seeley-Gilkey coefficients for the fourth-order operators on a Riemannian manifold

    International Nuclear Information System (INIS)

    Gusynin, V.P.

    1989-01-01

    A new covariant method for computing the coefficients in the heat kernel expansion is suggested. It allows one to calculate Seeley-Gilkey coefficients for both minimal and nonminimal differential operators acting on a vector bundle over a Riemannian manifold. The coefficients for the fourth-order minimal operators in arbitrary dimension of the space are calculated. In contrast to the second-order operators the coefficients for the fourth-order (and higher) operators turn out to be essentially dependent on the space dimension. The algorithmic character of the method suggested allows one to calculate coefficients by computer using the analytical calculation system. 19 refs.; 1 fig

  7. Apparatus for measurement of coefficient of friction

    Science.gov (United States)

    Slifka, A. J.; Siegwarth, J. D.; Sparks, L. L.; Chaudhuri, Dilip K.

    1990-01-01

    An apparatus designed to measure the coefficient of friction in certain controlled atmospheres is described. The coefficient of friction observed during high-load tests was nearly constant, with an average value of 0.56. This value is in general agreement with that found in the literature and also with the initial friction coefficient value of 0.67 measured during self-mated friction of 440C steel in an oxygen environment.

  8. Extended obstruction tensors and renormalized volume coefficients

    OpenAIRE

    Graham, C. Robin

    2009-01-01

    The behavior under conformal change of the renormalized volume coefficients associated to a pseudo-Riemannian metric is investigated. It is shown that they define second order fully nonlinear operators in the conformal factor whose algebraic structure is elucidated via the introduction of "extended obstruction tensors". These together with the Schouten tensor constitute building blocks for the coefficients in the ambient metric expansion. The renormalized volume coefficients have recently bee...

  9. Index-free Heat Kernel Coefficients

    OpenAIRE

    van de Ven, Anton E. M.

    1997-01-01

    Using index-free notation, we present the diagonal values of the first five heat kernel coefficients associated with a general Laplace-type operator on a compact Riemannian space without boundary. The fifth coefficient appears here for the first time. For a flat space with a gauge connection, the sixth coefficient is given too. Also provided are the leading terms for any coefficient, both in ascending and descending powers of the Yang-Mills and Riemann curvatures, to the same order as require...

  10. Comparing linear probability model coefficients across groups

    DEFF Research Database (Denmark)

    Holm, Anders; Ejrnæs, Mette; Karlson, Kristian Bernt

    2015-01-01

    This article offers a formal identification analysis of the problem in comparing coefficients from linear probability models between groups. We show that differences in coefficients from these models can result not only from genuine differences in effects, but also from differences in one or more...... of the following three components: outcome truncation, scale parameters and distributional shape of the predictor variable. These results point to limitations in using linear probability model coefficients for group comparisons. We also provide Monte Carlo simulations and real examples to illustrate...... these limitations, and we suggest a restricted approach to using linear probability model coefficients in group comparisons....

  11. Asymmetrical slip propensity: required coefficient of friction.

    Science.gov (United States)

    Seo, Jung-suk; Kim, Sukwon

    2013-07-31

    Most studies in performing slips and falls research reported their results after the ipsilateral leg of subjects (either right foot or left foot) was guided to contact the contaminated floor surface although many studies indicated concerns for asymmetries of legs in kinematic or kinetic variables. Thus, the present study evaluated if dominant leg's slip tendency would be different from non-dominant leg's slip tendency by comparing the Required Coefficient of Friction (RCOF) of the two lower limbs. Forty seven health adults participated in the present study. RCOF was measured when left or right foot of subjects contacted the force platforms respectively. Paired t-test was performed to test if RCOF and heel velocity (HCV) of dominant legs was different from that of non-dominant legs. It was suggested that the asymmetry in RCOFs and HCV between the two lower limbs existed. The RCOFs of non-dominant legs were higher than that of dominant legs. The results indicated that asymmetry in slip propensity, RCOF, was existed in lower extremity. The results from the study suggested that it would be benefit to include a variable, such as asymmetry, in slips and falls research.

  12. Probability based calibration of pressure coefficients

    DEFF Research Database (Denmark)

    Hansen, Svend Ole; Pedersen, Marie Louise; Sørensen, John Dalsgaard

    2015-01-01

    .3, the Eurocode partial factor of 1.5 for variable actions agrees well with the inherent uncertainties of wind actions when the pressure coefficients are determined using wind tunnel test results. The increased bias and uncertainty when pressure coefficients mainly are based on structural codes lead to a larger...

  13. Problems with Discontinuous Diffusion/Dispersion Coefficients

    Directory of Open Access Journals (Sweden)

    Stefano Ferraris

    2012-01-01

    accurate on smooth solutions and based on a special numerical treatment of the diffusion/dispersion coefficients that makes its application possible also when such coefficients are discontinuous. Numerical experiments confirm the convergence of the numerical approximation and show a good behavior on a set of benchmark problems in two space dimensions.

  14. Parabolic by Shilov systems with variable coefficients

    Directory of Open Access Journals (Sweden)

    V. A. Litovchenko

    2017-12-01

    Full Text Available Because of the parabolic instability of the Shilov systems to change their coefficients, the definition parabolicity of Shilov for systems with time-dependent $t$ coefficients, unlike the definition parabolicity of Petrovsky, is formulated by imposing conditions on the matricant of corresponding dual by Fourier system. For parabolic systems by Petrovsky with time-dependent coefficients, these conditions are the property of a matricant, which follows directly from the definition of parabolicity. In connection with this, the question of the wealth of the class Shilov systems with time-dependent coefficients is important.A new class of linear parabolic systems with partial derivatives to the first order by the time $t$ with time-dependent coefficients is considered in this work. It covers the class by Petrovsky systems with time-dependent younger coefficients. A main part of differential expression of each such system is parabolic (by Shilov expression with constant coefficients. The fundamental solution of the Cauchy problem for systems of this class is constructed by the Fourier transform method. Also proved their parabolicity by Shilov. Only the structure of the system and the conditions on the eigenvalues of the matrix symbol were used. First of all, this class characterizes the wealth by Shilov class of systems with time-dependents coefficients.Also it is given a general method for investigating a fundamental solution of the Cauchy problem for Shilov parabolic systems with positive genus, which is the development of the well-known method of Y.I. Zhitomirskii.

  15. A gain-coefficient switched Alexandrite laser

    International Nuclear Information System (INIS)

    Lee, Chris J; Van der Slot, Peter J M; Boller, Klaus-J

    2013-01-01

    We report on a gain-coefficient switched Alexandrite laser. An electro-optic modulator is used to switch between high and low gain states by making use of the polarization dependent gain of Alexandrite. In gain-coefficient switched mode, the laser produces 85 ns pulses with a pulse energy of 240 mJ at a repetition rate of 5 Hz.

  16. Prediction of friction coefficients for gases

    Science.gov (United States)

    Taylor, M. F.

    1969-01-01

    Empirical relations are used for correlating laminar and turbulent friction coefficients for gases, with large variations in the physical properties, flowing through smooth tubes. These relations have been used to correlate friction coefficients for hydrogen, helium, nitrogen, carbon dioxide and air.

  17. Coefficient Alpha Bootstrap Confidence Interval under Nonnormality

    Science.gov (United States)

    Padilla, Miguel A.; Divers, Jasmin; Newton, Matthew

    2012-01-01

    Three different bootstrap methods for estimating confidence intervals (CIs) for coefficient alpha were investigated. In addition, the bootstrap methods were compared with the most promising coefficient alpha CI estimation methods reported in the literature. The CI methods were assessed through a Monte Carlo simulation utilizing conditions…

  18. Heat transfer coefficient for boiling carbon dioxide

    DEFF Research Database (Denmark)

    Knudsen, Hans Jørgen Høgaard; Jensen, Per Henrik

    1998-01-01

    Heat transfer coefficient and pressure drop for boiling carbon dioxide (R744) flowing in a horizontal pipe has been measured. The calculated heat transfer coeeficient has been compared with the Chart correlation of Shah. The Chart Correlation predits too low heat transfer coefficient but the ratio...

  19. Estimating Runoff Coefficients Using Weather Radars

    DEFF Research Database (Denmark)

    Ahm, Malte; Thorndahl, Søren Liedtke; Rasmussen, Michael R.

    2012-01-01

    This paper presents a method for estimating runoff coefficients of urban drainage catchments based on a combination of high resolution weather radar data and insewer flow measurements. By utilising the spatial variability of the precipitation it is possible to estimate the runoff coefficients...

  20. Regularity of the interband light absorption coefficient

    Indian Academy of Sciences (India)

    In experimental studies the absorption coefficient is a means to study the band gaps at ... to l2( ), where. ⊂ Zd is a finite set. (usually taken to be a lattice cube centred at the origin) and λ±,uλ± are eigenvalues and eigenfunctions of H. ±. ,ω . Then the interband light absorption coefficient A for such finite volume models can.

  1. Helioseismic Solar Cycle Changes and Splitting Coefficients

    Indian Academy of Sciences (India)

    tribpo

    Abstract. Using the GONG data for a period over four years, we have studied the variation of frequencies and splitting coefficients with solar cycle. Frequencies and even-order coefficients are found to change signi- ficantly with rising phase of the solar cycle. We also find temporal varia- tions in the rotation rate near the solar ...

  2. Determination of the surface drag coefficient

    DEFF Research Database (Denmark)

    Mahrt, L.; Vickers, D.; Sun, J.L.

    2001-01-01

    This study examines the dependence of the surface drag coefficient on stability, wind speed, mesoscale modulation of the turbulent flux and method of calculation of the drag coefficient. Data sets over grassland, sparse grass, heather and two forest sites are analyzed. For significantly unstable ...

  3. Implications of NGA for NEHRP site coefficients

    Science.gov (United States)

    Borcherdt, Roger D.

    2012-01-01

    Three proposals are provided to update tables 11.4-1 and 11.4-2 of Minimum Design Loads for Buildings and Other Structures (7-10), by the American Society of Civil Engineers (2010) (ASCE/SEI 7-10), with site coefficients implied directly by NGA (Next Generation Attenuation) ground motion prediction equations (GMPEs). Proposals include a recommendation to use straight-line interpolation to infer site coefficients at intermediate values of ̅vs (average shear velocity). Site coefficients are recommended to ensure consistency with ASCE/SEI 7-10 MCER (Maximum Considered Earthquake) seismic-design maps and simplified site-specific design spectra procedures requiring site classes with associated tabulated site coefficients and a reference site class with unity site coefficients. Recommended site coefficients are confirmed by independent observations of average site amplification coefficients inferred with respect to an average ground condition consistent with that used for the MCER maps. The NGA coefficients recommended for consideration are implied directly by the NGA GMPEs and do not require introduction of additional models.

  4. Gini coefficient as a life table function

    Directory of Open Access Journals (Sweden)

    2003-06-01

    Full Text Available This paper presents a toolkit for measuring and analyzing inter-individual inequality in length of life by Gini coefficient. Gini coefficient and four other inequality measures are defined on the length-of-life distribution. Properties of these measures and their empirical testing on mortality data suggest a possibility for different judgements about the direction of changes in the degree of inequality by using different measures. A new computational procedure for the estimation of Gini coefficient from life tables is developed and tested on about four hundred real life tables. The estimates of Gini coefficient are precise enough even for abridged life tables with the final age group of 85+. New formulae have been developed for the decomposition of differences between Gini coefficients by age and cause of death. A new method for decomposition of age-components into effects of mortality and composition of population by group is developed. Temporal changes in the effects of elimination of causes of death on Gini coefficient are analyzed. Numerous empirical examples show: Lorenz curves for Sweden, Russia and Bangladesh in 1995, proportional changes in Gini coefficient and four other measures of inequality for the USA in 1950-1995 and for Russia in 1959-2000. Further shown are errors of estimates of Gini coefficient when computed from various types of mortality data of France, Japan, Sweden and the USA in 1900-95, decompositions of the USA-UK difference in life expectancies and Gini coefficients by age and cause of death in 1997. As well, effects of elimination of major causes of death in the UK in 1951-96 on Gini coefficient, age-specific effects of mortality and educational composition of the Russian population on changes in life expectancy and Gini coefficient between 1979 and 1989. Illustrated as well are variations in life expectancy and Gini coefficient across 32 countries in 1996-1999 and associated changes in life expectancy and Gini

  5. Experimental approach for measuring cylindrical flexoelectric coefficients

    Science.gov (United States)

    Zhang, Shuwen; Liu, Kaiyuan; Wu, Tonghui; Xu, Minglong; Shen, Shengping

    2017-10-01

    Flexoelectricity is a property of dielectric materials by which applied strain gradients induce electric polarizations within dielectric materials. Experimental research into the tensor components of the flexoelectric coefficient is essential. In this work, an experimental approach for measurement of the flexoelectric coefficient tensor components in cylindrical coordinates is developed. Two different experimental methods are designed to obtain the two related unknown flexoelectric coefficient tensor components. Theoretical and finite element analyses are developed and simplified for each experiment, and the related designs are then tested to obtain the coupled electric polarization charges. The two unknown flexoelectric coefficient tensor components of polyvinylidene fluoride are then decoupled. This work provides an experimental method that can be used to obtain multiple unknown flexoelectric coefficient tensor components in solid dielectric materials.

  6. A study on a characteristic of stem friction coefficient for motor operated flexible wedge gate valve

    International Nuclear Information System (INIS)

    Kim, Dae-Woong; Park, Sung-Geun; Lee, Sang-Guk; Kang, Shin-Cheul

    2009-01-01

    Stem friction coefficient is a coefficient that represents friction between thread leads of the stem and stem nut. It is an important factor to determine output thrust delivered from the actuator to the valve stem in assessing performance of motor operated valves. This study analyzes the effects of changes in differential pressure on stem friction coefficient, and determines the bounding value of stem friction coefficient. A dynamic test was conducted on multiple flexible wedge gate valves in various differential pressure conditions, and the test data was statistically analyzed to determine the bounding value. The results show that stem friction coefficient in middle and high differential pressure is influenced by fluid pressure, while stem friction coefficient in low differential pressure is almost not affected by fluid pressure. In addition, it is found that the bounding value of stem friction coefficient is higher in a closing stroke than in an opening stroke.

  7. Development of database on the distribution coefficient. 1. Collection of the distribution coefficient data

    Energy Technology Data Exchange (ETDEWEB)

    Takebe, Shinichi; Abe, Masayoshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2001-03-01

    The distribution coefficient is very important parameter for environmental impact assessment on the disposal of radioactive waste arising from research institutes. The literature survey in the country was mainly carried out for the purpose of selecting the reasonable distribution coefficient value on the utilization of this value in the safety evaluation. This report was arranged much informations on the distribution coefficient for inputting to the database for each literature, and was summarized as a literature information data on the distribution coefficient. (author)

  8. Variation in aerodynamic coefficients with altitude

    Directory of Open Access Journals (Sweden)

    Faiza Shahid

    Full Text Available Precise aerodynamics performance prediction plays key role for a flying vehicle to get its mission completed within desired accuracy. Aerodynamic coefficients for same Mach number can be different at different altitude due to difference in Reynolds number. Prediction of these aerodynamics coefficients can be made through experiments, analytical solution or Computational Fluid Dynamics (CFD. Advancements in computational power have generated the concept of using CFD as a virtual Wind Tunnel (WT, hence aerodynamic performance prediction in present study is based upon CFD (numerical test rig. Simulations at different altitudes for a range of Mach numbers with zero angle of attack are performed to predict axial force coefficient behavior with altitude (Reynolds number. Similar simulations for a fixed Mach number ‘3’ and a range of angle of attacks are also carried out to envisage the variation in normal force and pitching moment coefficients with altitude (Reynolds number. Results clearly depict that the axial force coefficient is a function of altitude (Reynolds number and increase as altitude increases, especially for subsonic region. Variation in axial force coefficient with altitude (Reynolds number slightly increases for larger values of angle of attacks. Normal force and pitching moment coefficients do not depend on altitude (Reynolds number at smaller values of angle of attacks but show slight decrease as altitude increases. Present study suggests that variation of normal force and pitching moment coefficients with altitude can be neglected but the variation of axial force coefficient with altitude should be considered for vehicle fly in dense atmosphere. It is recommended to continue this study to more complex configurations for various Mach numbers with side slip and real gas effects. Keywords: Mach number, Reynolds number, Blunt body, Altitude effect, Angle of attacks

  9. Variation in aerodynamic coefficients with altitude

    Science.gov (United States)

    Shahid, Faiza; Hussain, Mukkarum; Baig, Mirza Mehmood; Haq, Ihtram ul

    Precise aerodynamics performance prediction plays key role for a flying vehicle to get its mission completed within desired accuracy. Aerodynamic coefficients for same Mach number can be different at different altitude due to difference in Reynolds number. Prediction of these aerodynamics coefficients can be made through experiments, analytical solution or Computational Fluid Dynamics (CFD). Advancements in computational power have generated the concept of using CFD as a virtual Wind Tunnel (WT), hence aerodynamic performance prediction in present study is based upon CFD (numerical test rig). Simulations at different altitudes for a range of Mach numbers with zero angle of attack are performed to predict axial force coefficient behavior with altitude (Reynolds number). Similar simulations for a fixed Mach number '3' and a range of angle of attacks are also carried out to envisage the variation in normal force and pitching moment coefficients with altitude (Reynolds number). Results clearly depict that the axial force coefficient is a function of altitude (Reynolds number) and increase as altitude increases, especially for subsonic region. Variation in axial force coefficient with altitude (Reynolds number) slightly increases for larger values of angle of attacks. Normal force and pitching moment coefficients do not depend on altitude (Reynolds number) at smaller values of angle of attacks but show slight decrease as altitude increases. Present study suggests that variation of normal force and pitching moment coefficients with altitude can be neglected but the variation of axial force coefficient with altitude should be considered for vehicle fly in dense atmosphere. It is recommended to continue this study to more complex configurations for various Mach numbers with side slip and real gas effects.

  10. Soccer ball lift coefficients via trajectory analysis

    Energy Technology Data Exchange (ETDEWEB)

    Goff, John Eric [Department of Physics, Lynchburg College, Lynchburg, VA 24501 (United States); Carre, Matt J, E-mail: goff@lynchburg.ed [Department of Mechanical Engineering, University of Sheffield, Sheffield S1 3JD (United Kingdom)

    2010-07-15

    We performed experiments in which a soccer ball was launched from a machine while two high-speed cameras recorded portions of the trajectory. Using the trajectory data and published drag coefficients, we extracted lift coefficients for a soccer ball. We determined lift coefficients for a wide range of spin parameters, including several spin parameters that have not been obtained by today's wind tunnels. Our trajectory analysis technique is not only a valuable tool for professional sports scientists, it is also accessible to students with a background in undergraduate-level classical mechanics.

  11. Exceptional high Seebeck coefficient and gas-flow-induced voltage in multilayer graphene

    Science.gov (United States)

    Li, Xuemei; Yin, Jun; Zhou, Jianxin; Wang, Qin; Guo, Wanlin

    2012-04-01

    Seebeck coefficient of graphene is an important parameter for defining its thermoelectric performance and thus practical applications, such as gas-flow-induced voltage. Here, we find a unique layer-dependence of the graphene Seebeck coefficient that exceptionally increases with increasing thickness to reach a peak value at six layers that is ˜77% higher than monolayer and ˜296% higher than graphite, unlike the monotonic decrease in electric resistance. However, the gas flow-induced voltage is significantly higher in 2, 4, 5, 6, and 7 layered graphene samples than in 1, 3, and 8 layered ones, against the prevailing wisdom that it should be proportional to Seebeck coefficient.

  12. Transport Coefficients from Large Deviation Functions

    Directory of Open Access Journals (Sweden)

    Chloe Ya Gao

    2017-10-01

    Full Text Available We describe a method for computing transport coefficients from the direct evaluation of large deviation functions. This method is general, relying on only equilibrium fluctuations, and is statistically efficient, employing trajectory based importance sampling. Equilibrium fluctuations of molecular currents are characterized by their large deviation functions, which are scaled cumulant generating functions analogous to the free energies. A diffusion Monte Carlo algorithm is used to evaluate the large deviation functions, from which arbitrary transport coefficients are derivable. We find significant statistical improvement over traditional Green–Kubo based calculations. The systematic and statistical errors of this method are analyzed in the context of specific transport coefficient calculations, including the shear viscosity, interfacial friction coefficient, and thermal conductivity.

  13. Friction coefficient dependence on electrostatic tribocharging.

    Science.gov (United States)

    Burgo, Thiago A L; Silva, Cristiane A; Balestrin, Lia B S; Galembeck, Fernando

    2013-01-01

    Friction between dielectric surfaces produces patterns of fixed, stable electric charges that in turn contribute electrostatic components to surface interactions between the contacting solids. The literature presents a wealth of information on the electronic contributions to friction in metals and semiconductors but the effect of triboelectricity on friction coefficients of dielectrics is as yet poorly defined and understood. In this work, friction coefficients were measured on tribocharged polytetrafluoroethylene (PTFE), using three different techniques. As a result, friction coefficients at the macro- and nanoscales increase many-fold when PTFE surfaces are tribocharged, but this effect is eliminated by silanization of glass spheres rolling on PTFE. In conclusion, tribocharging may supersede all other contributions to macro- and nanoscale friction coefficients in PTFE and probably in other insulating polymers.

  14. Roughness coefficients for stream channels in Arizona

    Science.gov (United States)

    Aldridge, B.N.; Garrett, J.M.

    1973-01-01

    When water flows in an open channel, energy is lost through friction along the banks and bed of the channel and through turbulence within the channel. The amount of energy lost is governed by channel roughness, which is expressed in terms of a roughness coefficient. An evaluation of the roughness coefficient is necessary in many hydraulic computations that involve flow in an open channel. Owing to the lack of satisfactory quantitative procedure, the ability of evaluate roughness coefficients can be developed only through experience; however, a basic knowledge of the methods used to assign the coefficients and the factors affecting them will be a great help. One of the most commonly used equations in open-channel hydraulics is that of Manning. The Manning equation is       1.486

  15. Explicit formulas for Clebsch-Gordan coefficients

    International Nuclear Information System (INIS)

    Rudnicki-Bujnowski, G.

    1975-01-01

    The problem is to obtain explicit algebraic formulas of Clebsch-Gordan coefficients for high values of angular momentum. The method of solution is an algebraic method based on the Racah formula using the FORMAC programming language. (Auth.)

  16. Second coefficient of viscosity in air

    Science.gov (United States)

    Ash, Robert L.; Zuckerwar, Allan J.; Zheng, Zhonquan

    1991-01-01

    Acoustic attenuation measurements in air were analyzed in order to estimate the second coefficient of viscosity. Data over a temperature range of 11 C to 50 C and at relative humidities between 6 percent and 91 percent were used. This analysis showed that the second coefficient of viscosity varied between 1900 and 20,000 times larger than the dynamic or first coefficient of viscosity over the temperature and humidity range of the data. In addition, the data showed that the molecular relaxation effects, which are responsible for the magnitude of the second coefficient of viscosity, place severe limits on the use of time-independent, thermodynamic equations of state. Compressible flows containing large streamwise velocity gradients, like shock waves, which cause significant changes in particle properties to occur during time intervals shorter than hundredths of seconds, must be modeled using dynamic equations of state. The dynamic model approach is described briefly.

  17. Heat transfer coefficient of cryotop during freezing.

    Science.gov (United States)

    Li, W J; Zhou, X L; Wang, H S; Liu, B L; Dai, J J

    2013-01-01

    Cryotop is an efficient vitrification method for cryopreservation of oocytes. It has been widely used owing to its simple operation and high freezing rate. Recently, the heat transfer performance of cryotop was studied by numerical simulation in several studies. However, the range of heat transfer coefficient in the simulation is uncertain. In this study, the heat transfer coefficient for cryotop during freezing process was analyzed. The cooling rates of 40 percent ethylene glycol (EG) droplet in cryotop during freezing were measured by ultra-fast measurement system and calculated by numerical simulation at different value of heat transfer coefficient. Compared with the results obtained by two methods, the range of the heat transfer coefficient necessary for the numerical simulation of cryotop was determined, which is between 9000 W/(m(2)·K) and 10000 W/(m (2)·K).

  18. Form coefficient of helical toroidal solenoids

    International Nuclear Information System (INIS)

    Amelin, V.Z.; Kunchenko, V.B.

    1982-01-01

    For toroidal solenoids with continuous spiral coil, winded according to the laws of equiinclined and simple cylindrical spirals with homogeneous, linearly increasing to the coil periphery and ''Bitter'' distribution of current density, the analytical expressions for the dependence between capacity consumed and generated magnetic field, expressions for coefficients of form similar to Fabry coefficient for cylindrical solenoids are obtained and dependence of the form coefficient and relative volume of solenoid conductor on the number of revolutions of screw line per one circumvention over the large torus radius is also investigated. Analytical expressions of form coefficients and graphical material permit to select the optimum geometry as to capacity consumed both for spiral (including ''force-free'') and conventional toroidal solenoids of magnetic systems in thermonulear installations

  19. Modeling Ballasted Tracks for Runoff Coefficient C

    Science.gov (United States)

    2012-08-01

    In this study, the Regional Transportation District (RTD)s light rail tracks were modeled to determine the Rational Method : runoff coefficient, C, values corresponding to ballasted tracks. To accomplish this, a laboratory study utilizing a : rain...

  20. Estimation of Okun Coefficient for Algeria

    OpenAIRE

    KORI YAHIA, Abdellah

    2018-01-01

    The objective of this paper is to investigate the presence of Okun’s (1962) relationship for Algeria for the 1970- 2015 period. Two methodologies are employed to estimate the Okun coefficient: An Autoregressive Distributed Lag (ARDL) linear model and a Bayesian Normal Linear Regression model. The results indicate an Okun coefficient of about -0.2 which suggests some rigidity of the labour market in Algeria.

  1. Measuring Resource Inequality: The Gini Coefficient

    Directory of Open Access Journals (Sweden)

    Michael T. Catalano

    2009-07-01

    Full Text Available This paper stems from work done by the authors at the Mathematics for Social Justice Workshop held in June of 2007 at Middlebury College. We provide a description of the Gini coefficient and some discussion of how it can be used to promote quantitative literacy skills in mathematics courses. The Gini Coefficient was introduced in 1921 by Italian statistician Corrado Gini as a measure of inequality. It is defined as twice the area between two curves. One, the Lorenz curve for a given population with respect to a given resource, represents the cumulative percentage of the resource as a function of the cumulative percentage of the population that shares that percentage of the resource. The second curve is the line y = x which is the Lorenz curve for a population which shares the resource equally. The Gini coefficient can be interpreted as the percentage of inequality represented in the population with respect to the given resource. We propose that the Gini coefficient can be used to enhance students’ understanding of calculus concepts and provide practice for students in using both calculus and quantitative literacy skills. Our examples are based mainly on distribution of energy resources using publicly available data from the Energy Information Agency of the United States Government. For energy resources within the United States, we find that by household, the Gini coefficient is 0.346, while using the 51 data points represented by the states and Washington D.C., the Gini coefficient is 0.158. When we consider the countries of the world as a population of 210, the Gini coefficient is 0.670. We close with ideas for questions which can be posed to students and discussion of the experiences two other mathematics instructors have had incorporating the Gini coefficient into pre-calculus-level mathematics classes.

  2. No signs of inbreeding despite long-term isolation and habitat fragmentation in the critically endangered Montseny brook newt (Calotriton arnoldi).

    Science.gov (United States)

    Valbuena-Ureña, E; Soler-Membrives, A; Steinfartz, S; Orozco-terWengel, P; Carranza, S

    2017-05-01

    Endemic species with restricted geographic ranges potentially suffer the highest risk of extinction. If these species are further fragmented into genetically isolated subpopulations, the risk of extinction is elevated. Habitat fragmentation is generally considered to have negative effects on species survival, despite some evidence for neutral or even positive effects. Typically, non-negative effects are ignored by conservation biology. The Montseny brook newt (Calotriton arnoldi) has one of the smallest distribution ranges of any European amphibian (8 km 2 ) and is considered critically endangered by the International Union for Conservation of Nature. Here we apply molecular markers to analyze its population structure and find that habitat fragmentation owing to a natural barrier has resulted in strong genetic division of populations into two sectors, with no detectable migration between sites. Although effective population size estimates suggest low values for all populations, we found low levels of inbreeding and relatedness between individuals within populations. Moreover, C. arnoldi displays similar levels of genetic diversity to its sister species Calotriton asper, from which it separated around 1.5 million years ago and which has a much larger distribution range. Our extensive study shows that natural habitat fragmentation does not result in negative genetic effects, such as the loss of genetic diversity and inbreeding on an evolutionary timescale. We hypothesize that species in such conditions may evolve strategies (for example, special mating preferences) to mitigate the effects of small population sizes. However, it should be stressed that the influence of natural habitat fragmentation on an evolutionary timescale should not be conflated with anthropogenic habitat loss or degradation when considering conservation strategies.

  3. Monitoring device for local power peaking coefficient

    International Nuclear Information System (INIS)

    Mitsuhashi, Ishi

    1987-01-01

    Purpose: To monitor the local power peaking coefficients obtained by the method not depending on the combination of fuel types. Method: A plurality of representative values for the local power distribution determined by the nuclear constant calculation for one fuel assembly are memorized regarding each of the burn-up degree and the void coefficient on every positions and fuel types in fuel rod assemblies. While on the other hand, the representative values for the local power distribution as described above are compensated by a compensation coefficient considering the effect of adjacent segments and a control rod compensation coefficient considering the effect due to the control rod insertion relative to the just-mentioned compensation coefficient. Then, the maximum value among them is selected to determine the local power peaking coefficient at each of the times and each of the segments, which is monitored. According to this system, the calculation and the working required for the fitting work depending on the combination of fuel types are no more required at all to facilitate the maintenance as well. (Horiuchi, T.)

  4. Posible origen hereditario de una Hipospadias que afecta a corderos con un alto grado de consanguinidad (Inherited origin suggested for hypospadias affecting to lambs with a low inbreeding coefficient).

    OpenAIRE

    Tejedor-Hernández, T; Monteagudo-Ibáñez,L; Verde-Arribas, MT; Ferrer-Mayayo,L.M; Ramos-Antón, JJ; Marteles-Aragüés, D; Borobia-Frías, M

    2009-01-01

    Resumen1Departamento de Patología Animal. Facultad de Veterinaria.Universidad de Zaragoza. 2Departamento de Anatomía, Embriología y Genética Animal. Facultad de Veterinaria. Universidad de Zaragoza.E-mail: mailto: La hipospadias es una de las anomalías más frecuentes que afecta al pene en humanos. Se considera que su origen tiene una base genética y se han propuesto varios modelos de herencia: autosómica recesiva, autosómica dominante, ligada al cromosoma X o un patrón...

  5. Lattice cell diffusion coefficients. Definitions and comparisons

    International Nuclear Information System (INIS)

    Hughes, R.P.

    1980-01-01

    Definitions of equivalent diffusion coefficients for regular lattices of heterogeneous cells have been given by several authors. The paper begins by reviewing these different definitions and the unification of their derivation. This unification makes clear how accurately each definition (together with appropriate cross-section definitions to preserve the eigenvalue) represents the individual reaction rates within the cell. The approach can be extended to include asymmetric cells and whereas before, the buckling describing the macroscopic flux shape was real, here it is found to be complex. A neutron ''drift'' coefficient as well as a diffusion coefficient is necessary to produce the macroscopic flux shape. The numerical calculation of the various different diffusion coefficients requires the solutions of equations similar to the ordinary transport equation for an infinite lattice. Traditional reactor physics codes are not sufficiently flexible to solve these equations in general. However, calculations in certain simple cases are presented and the theoretical results quantified. In difficult geometries, Monte Carlo techniques can be used to calculate an effective diffusion coefficient. These methods relate to those already described provided that correlation effects between different generations of neutrons are included. Again, these effects are quantified in certain simple cases. (author)

  6. Experimental methodology for obtaining sound absorption coefficients

    Directory of Open Access Journals (Sweden)

    Carlos A. Macía M

    2011-07-01

    Full Text Available Objective: the authors propose a new methodology for estimating sound absorption coefficients using genetic algorithms. Methodology: sound waves are generated and conducted along a rectangular silencer. The waves are then attenuated by the absorbing material covering the silencer’s walls. The attenuated sound pressure level is used in a genetic algorithm-based search to find the parameters of the proposed attenuation expressions that include geometric factors, the wavelength and the absorption coefficient. Results: a variety of adjusted mathematical models were found that make it possible to estimate the absorption coefficients based on the characteristics of a rectangular silencer used for measuring the attenuation of the noise that passes through it. Conclusions: this methodology makes it possible to obtain the absorption coefficients of new materials in a cheap and simple manner. Although these coefficients might be slightly different from those obtained through other methodologies, they provide solutions within the engineering accuracy ranges that are used for designing noise control systems.

  7. Radon emanation coefficients in sandy soils

    International Nuclear Information System (INIS)

    Holy, K.; Polaskova, A.; Baranova, A.; Sykora, I.; Hola, O.

    1998-01-01

    In this contribution the results of the study of an influence of the water content on the emanation coefficient for two sandy soil samples are reported. These samples were chosen on the because of the long-term continual monitoring of the 222 Rn concentration just in such types of soils and this radon concentration showed the significant variations during a year. These variations are chiefly given in connection with the soil moisture. Therefore, the determination of the dependence of the emanation coefficient of radon on the water content can help to evaluate the influence of the soil moisture variations of radon concentrations in the soil air. The presented results show that the emanation coefficient reaches the constant value in the wide interval of the water content for both sandy soil samples. Therefore, in the common range of the soil moisture (5 - 20 %) it is impossible to expect the variations of the radon concentration in the soil air due to the change of the emanation coefficient. The expressive changes of the radon concentration in the soil air can be observed in case of the significant decrease of the emanation coefficient during the soil drying when the water content decreases under 5 % or during the complete filling of the soil pores by the water. (authors)

  8. Computation of Clebsch-Gordan and Gaunt coefficients using binomial coefficients

    International Nuclear Information System (INIS)

    Guseinov, I.I.; Oezmen, A.; Atav, Ue

    1995-01-01

    Using binomial coefficients the Clebsch-Gordan and Gaunt coefficients were calculated for extremely large quantum numbers. The main advantage of this approach is directly calculating these coefficients, instead of using recursion relations. Accuracy of the results is quite high for quantum numbers l 1 , and l 2 up to 100. Despite direct calculation, the CPU times are found comparable with those given in the related literature. 11 refs., 1 fig., 2 tabs

  9. Curvature of Indoor Sensor Network: Clustering Coefficient

    Directory of Open Access Journals (Sweden)

    2009-03-01

    Full Text Available We investigate the geometric properties of the communication graph in realistic low-power wireless networks. In particular, we explore the concept of the curvature of a wireless network via the clustering coefficient. Clustering coefficient analysis is a computationally simplified, semilocal approach, which nevertheless captures such a large-scale feature as congestion in the underlying network. The clustering coefficient concept is applied to three cases of indoor sensor networks, under varying thresholds on the link packet reception rate (PRR. A transition from positive curvature (“meshed” network to negative curvature (“core concentric” network is observed by increasing the threshold. Even though this paper deals with network curvature per se, we nevertheless expand on the underlying congestion motivation, propose several new concepts (network inertia and centroid, and finally we argue that greedy routing on a virtual positively curved network achieves load balancing on the physical network.

  10. Nozzle geometry variations on the discharge coefficient

    Directory of Open Access Journals (Sweden)

    M.M.A. Alam

    2016-03-01

    Full Text Available Numerical works have been conducted to investigate the effect of nozzle geometries on the discharge coefficient. Several contoured converging nozzles with finite radius of curvatures, conically converging nozzles and conical divergent orifices have been employed in this investigation. Each nozzle and orifice has a nominal exit diameter of 12.7×10−3 m. A 3rd order MUSCL finite volume method of ANSYS Fluent 13.0 was used to solve the Reynolds-averaged Navier–Stokes equations in simulating turbulent flows through various nozzle inlet geometries. The numerical model was validated through comparison between the numerical results and experimental data. The results obtained show that the nozzle geometry has pronounced effect on the sonic lines and discharge coefficients. The coefficient of discharge was found differ from unity due to the non-uniformity of flow parameters at the nozzle exit and the presence of boundary layer as well.

  11. Control in the coefficients with variational crimes

    DEFF Research Database (Denmark)

    Evgrafov, Anton; Marhadi, Kun Saptohartyadi

    2012-01-01

    We study convergence of discontinuous Galerkin-type discretizations of the problems of control in the coefficients of uniformly elliptic partial differential equations (PDEs). As a model problem we use that of the optimal design of thin (Kirchhoff) plates, where the governing equations are of the......We study convergence of discontinuous Galerkin-type discretizations of the problems of control in the coefficients of uniformly elliptic partial differential equations (PDEs). As a model problem we use that of the optimal design of thin (Kirchhoff) plates, where the governing equations...... to “volumetric” Lebesgue norm, changes of the coefficients is generally speaking not continuous. We utilize the lifting formulation of the discontinuous Galerkin method to deal with this issue.Our main result is that limit points of sequences of designs verifying discrete versions of stationarity can also...

  12. Optical distortion coefficients of laser windows

    International Nuclear Information System (INIS)

    Klein, C.A.

    1989-01-01

    This paper addresses the problem of describing and evaluating thermal lensing phenomena that occur as a result of the absorption of laser light in solid windows. The aberration-function expansion method is applied for deriving the two optical distortion coefficients χ + and χ - that characterize the degradation in light intensity at the Gaussian focus of an initially diffraction-limited laser beam passing through a weakly absorbing stress-birefringent window. In a pulsed mode of operation, the concept of an effective optical distortion coefficient. χ eff, which properly combines the coefficients χ + and χ - in terms of potential impact on focal irradiances, then leads to the definition of a figure of merit for distortion. The theory and the calculations presented in this papers provide simple analytical tools for predicting the optical performance of a window-material candidate in a specific system's environment

  13. The HD+ dissociative recombination rate coefficient at low temperature

    Directory of Open Access Journals (Sweden)

    Wolf A.

    2015-01-01

    Full Text Available The effect of the rotational temperature of the ions is considered for low-energy dissociative recombination (DR of HD+. Merged beams measurements with HD+ ions of a rotational temperature near 300 K are compared to multichannel quantum defect theory calculations. The thermal DR rate coefficient for a Maxwellian electron velocity distribution is derived from the merged-beams data and compared to theoretical results for a range of rotational temperatures. Good agreement is found for the theory with 300 K rotational temperature. For a low-temperature plasma environment where also the rotational temperature assumes 10 K, theory predicts a considerably higher thermal DR rate coefficient. The origin of this is traced to predicted resonant structures of the collision-energy dependent DR cross section at few-meV collision energies for the particular case of HD+ ions in the rotational ground state.

  14. Content based image retrieval based on wavelet transform coefficients distribution.

    Science.gov (United States)

    Lamard, Mathieu; Cazuguel, Guy; Quellec, Gwénolé; Bekri, Lynda; Roux, Christian; Cochener, Béatrice

    2007-01-01

    In this paper we propose a content based image retrieval method for diagnosis aid in medical fields. We characterize images without extracting significant features by using distribution of coefficients obtained by building signatures from the distribution of wavelet transform. The research is carried out by computing signature distances between the query and database images. Several signatures are proposed; they use a model of wavelet coefficient distribution. To enhance results, a weighted distance between signatures is used and an adapted wavelet base is proposed. Retrieval efficiency is given for different databases including a diabetic retinopathy, a mammography and a face database. Results are promising: the retrieval efficiency is higher than 95% for some cases using an optimization process.

  15. Content Based Image Retrieval based on Wavelet Transform coefficients distribution

    Science.gov (United States)

    Lamard, Mathieu; Cazuguel, Guy; Quellec, Gwénolé; Bekri, Lynda; Roux, Christian; Cochener, Béatrice

    2007-01-01

    In this paper we propose a content based image retrieval method for diagnosis aid in medical fields. We characterize images without extracting significant features by using distribution of coefficients obtained by building signatures from the distribution of wavelet transform. The research is carried out by computing signature distances between the query and database images. Several signatures are proposed; they use a model of wavelet coefficient distribution. To enhance results, a weighted distance between signatures is used and an adapted wavelet base is proposed. Retrieval efficiency is given for different databases including a diabetic retinopathy, a mammography and a face database. Results are promising: the retrieval efficiency is higher than 95% for some cases using an optimization process. PMID:18003013

  16. Design of wind turbine airfoils based on maximum power coefficient

    DEFF Research Database (Denmark)

    Cheng, Jiangtao; Chen, Jin; Cheng, Jiangtao

    2010-01-01

    Based on the blade element momentum (BEM) theory, the power coefficient of a wind turbine can be expressed in function of local tip speed ratio and lift-drag ratio. By taking the power coefficient in a predefined range of angle of attack as the final design objective and combining with an airfoil...... behaviors, noise emission as well as wind turbine service life. To show the performance of the new design technique, a new airfoil with relative thickness of 18% is designed. Comparisons with a wind turbine airfoil (NACA 63418) at Re=2×106 and Re=6×106 for free and fixed transitions show that the new...... airfoil has a higher power efficiency, better designed lift at off-design condition, better stall behavior, less sensitivity to leading edge roughness and lower noise emission. © 2010 Journal of Mechanical Engineering....

  17. Inbred decorated crickets exhibit higher measures of macroparasitic immunity than outbred individuals.

    Science.gov (United States)

    Gershman, S N; Barnett, C A; Pettinger, A M; Weddle, C B; Hunt, J; Sakaluk, S K

    2010-09-01

    Inbreeding is assumed to have negative effects on fitness, including the reduced ability to withstand immune challenges. We examined the immunological consequences of inbreeding in decorated crickets, Gryllodes sigillatus, by comparing lytic activity, phenoloxidase (PO) activity, and encapsulation ability of crickets from eight inbred lines with that of crickets from the outbred founder population. Surprisingly, crickets from inbred lines had a greater encapsulation ability compared with crickets from the outbred population. We suggest that because inbred crickets have reduced reproductive effort, they may, therefore, have the option of devoting more resources to this form of immunity than outbred individuals. We also found that both inbred and outbred females had higher immunity than males in PO activity and implant darkness. This result supports the hypothesis that females should devote more effort to somatic maintenance and immunity than males. PO activity and implant darkness were heritable in both males and females, but lytic activity was only heritable in females. Males and females differed in the heritability of, and genetic correlations among, immune traits, suggesting that differences in selective pressures on males and females may have resulted in a sexual conflict over optimal immune trait values.

  18. Criterions for fixing regulatory seismic acceleration coefficients

    International Nuclear Information System (INIS)

    Costes, D.

    1988-03-01

    Acceleration coeffficients to be taken into account in seismic areas for calculation of structures are defined in national seismic regulations. Joined to the described qualitative requirements, these coefficients represent a balance between precaution costs and avoided damages, both in terms of material repairing costs and damage to human life. Persons in charge of fixing these coefficients must be informed of corresponding quantitative aspects. Data on seismic motions occurrencies and consequences are gathered here and convoluted to mean damage evaluations. Indications on precaution costs are joined, which shows that currently recommended levels of seismic motions are high relatively to financial profitability, and represent in fact an aethical choice about human life value [fr

  19. Dependence of sputtering coefficient on ion dose

    International Nuclear Information System (INIS)

    Colligon, J.S.; Patel, M.H.

    1977-01-01

    The sputtering coefficient of polycrystalline gold bombarded by 10-40 keV Ar + ions had been measured as a function of total ion dose and shown to exhibit oscillations in magnitude between 30 and 100%. Possible experimental errors which would give rise to such an oscillation have been considered, but it is apparent that these factors are unable to explain the measurements. It is proposed that a change in the Sublimation Energy associated with either bulk damage or formation of surface topographical features arising during ion bombardment may be responsible for the observed variations in sputtering coefficient. (author)

  20. Absorption coefficient instrument for turbid natural waters

    Science.gov (United States)

    Friedman, E.; Cherdak, A.; Poole, L.; Houghton, W.

    1980-01-01

    The paper presents an instrument that directly measures multispectral absorption coefficient of turbid natural water. Attention is given to the design, which is shown to incorporate methods for the compensation of variation in the internal light source intensity, correction of the spectrally dependent nature of the optical elements, and correction for variation in the background light level. In addition, when used in conjunction with a spectrally matched total attenuation instrument, the spectrally dependent scattering coefficient can also be derived. Finally, it is reported that systematic errors associated with multiple scattering have been estimated using Monte Carlo techniques.

  1. A drying coefficient for building materials

    DEFF Research Database (Denmark)

    Scheffler, Gregor Albrecht; Plagge, Rudolf

    2009-01-01

    , in many cases such a coefficient would be highly appreciated, e.g. in interaction of industry and research or for the distinction and selection of suitable building materials throughout design and practise. This article first highlights the importance of drying experiments for hygrothermal...... and defined as a new and independent material parameter. It contains information about the moisture transport properties throughout the wide range of moisture contents from hygroscopic up to saturation. With this new and valuable coefficient, it is now possible to distinguish and select building materials...

  2. Shear viscosity coefficient of liquid lanthanides

    Energy Technology Data Exchange (ETDEWEB)

    Patel, H. P., E-mail: patel.harshal2@gmail.com; Thakor, P. B., E-mail: pbthakore@rediffmail.com; Prajapati, A. V., E-mail: anand0prajapati@gmail.com [Department of Physics, Veer Narmad South Gujarat University, Surat 395 007, Gujarat (India); Sonvane, Y. A., E-mail: yas@ashd.svnit.ac.in [Department of Applied Physics, S. V. National Institute of Technology, Surat 395 007, Gujarat (India)

    2015-05-15

    Present paper deals with the computation of shear viscosity coefficient (η) of liquid lanthanides. The effective pair potential v(r) is calculated through our newly constructed model potential. The Pair distribution function g(r) is calculated from PYHS reference system. To see the influence of local field correction function, Hartree (H), Tailor (T) and Sarkar et al (S) local field correction function are used. Present results are compared with available experimental as well as theoretical data. Lastly, we found that our newly constructed model potential successfully explains the shear viscosity coefficient (η) of liquid lanthanides.

  3. Reaction rate calculations via transmission coefficients

    International Nuclear Information System (INIS)

    Feit, M.D.; Alder, B.J.

    1985-01-01

    The transmission coefficient of a wavepacket traversing a potential barrier can be determined by steady state calculations carried out in imaginary time instead of by real time dynamical calculations. The general argument is verified for the Eckart barrier potential by a comparison of transmission coefficients calculated from real and imaginary time solutions of the Schroedinger equation. The correspondence demonstrated here allows a formulation for the reaction rate that avoids difficulties due to both rare events and explicitly time dependent calculations. 5 refs., 2 figs

  4. GENOMIC VARIABILITY AMONG CATTLE POPULATIONS BASED ON RUNS OF HOMOZYGOSITY

    Directory of Open Access Journals (Sweden)

    Veronika Šidlová

    2015-09-01

    Full Text Available In this work, the distribution of different lengths ROH (runs of homozygosity in six cattle breeds was described. A total of 122 animals from six cattle breeds (Holstein, Simmental, Austrian Pinzgau, Ayrshire, MRI-Meuse Rhine Issel and Slovak Pinzgau were analysed. The ROH approach was used to distinguish Slovak Pinzgau population from other investigated breeds as well as to differentiate between ancient and recent inbreeding. The average number of ROH per animal ranged from 17.06 in Holstein to 159.22 in Ayrshire. The highest number of short ROH (ancient inbreeding was found in Simmental, followed by Ayrshire. The Ayrshire and MRI had a higher proportion of longer ROH distributed across the whole genome, revealing recent inbreeding. ROH were identified and used to estimate molecular inbreeding coefficients (FROH. The highest level of inbreeding from the investigated breeds was found out in Ayrshire with the same tendency for all length categories compared to Slovak Pinzgau with higher ancient inbreeding. Ancient inbreeding was only observed in Holstein population. A similar trend is becoming apparent even for Slovak Pinzgau, showing the second smallest recent inbreeding. Therefore, it is necessary to preserve the given population in the original phenotype and prevent further increase of inbreeding especially in endangered breeds.

  5. Unbounded oscillation of higher-order nonlinear delay dynamic equations of neutral type with oscillating coefficients

    Directory of Open Access Journals (Sweden)

    Başak Karpuz

    2009-05-01

    where $n\\in[2,\\infty_{\\mathbb{Z}}$, $t_{0}\\in\\mathbb{T}$, $\\sup\\{\\mathbb{T}\\}=\\infty$, $A\\in\\rm{C_{rd}}([t_{0},\\infty_{\\mathbb{T}},\\mathbb{R}$ is allowed to alternate in sign infinitely many times, $B\\in\\rm{C_{rd}}([t_{0},\\infty_{\\mathbb{T}},\\mathbb{R}^{+}$, $F\\in\\rm{C_{rd}}(\\mathbb{R},\\mathbb{R}$ is nondecreasing, and $\\alpha,\\beta\\in\\rm{C_{rd}}([t_{0},\\infty_{\\mathbb{T}},\\mathbb{T}$ are unbounded increasing functions satisfying $\\alpha(t,\\beta(t\\leq t$ for all sufficiently large $t$. We give change of order formula for double(iterated integrals to prove our main result. Some simple examples are given to illustrate the applicability of our results too. In the literature, almost all of the results for \\eqref{asbeq1} with $\\mathbb{T}=\\mathbb{R}$ and $\\mathbb{T}=\\mathbb{Z}$ hold for bounded solutions. Our results are new and not stated in the literature even for the particular cases $\\mathbb{T}=\\mathbb{R}$ and/or $\\mathbb{T}=\\mathbb{Z}$.

  6. Validación de un método de selección para rendimiento en alfalfa basado en la depresión por endocría Validation of a selection technique for improving alfalfa forage yield based on inbreeding depression

    Directory of Open Access Journals (Sweden)

    V. Arolfo

    2011-06-01

    Full Text Available La rápida depresión por endocría en alfalfa obedece a la pérdida de interacciones alélicas intra-locus en plantas tri y tetraalélicas. Éstas podrían identificarse por una prueba de autofecundación y luego combinarse en una variedad sintética con mayor rendimiento forrajero. El objetivo de este trabajo fue evaluar la utilidad de la prueba de progenie S1 para identificar genotipos tri y tetraalélicos. Se desarrollaron tres poblaciones sintéticas experimentales (PSE de alfalfa según tres métodos de selección, partiendo de una población original (PO. El primero, seleccionando las plantas madres que presentaron mayor depresión por endocría (≥65% en el rendimiento de sus progenies S1; el segundo, seleccionando las plantas de la PO que no formaron semilla S1; el último consistió en la selección fenotípica tradicional de las plantas de la PO con mayores rendimientos (15% superior. Las seleccionadas fueron polinizadas y cosechadas manualmente, conformando las PSE 1, 2 y 3, respectivamente. Se evaluó la producción de forraje acumulada de cada PSE y PO durante la temporada. Todas las PSE superaron (pRapid inbreeding depression in alfalfa is due to loss of intraallelic interactions in tri- and tetraallelic plants. These plants could be identified by using a S1 progeny test and then combined into a higher yielding synthetic variety. The objective of this study was to evaluate the usefulness of S1 progeny test to identify tri and tetraallelic genotypes. Three alfalfa synthetic experimental populations (PSE were developed by applying three selection methods to an original plant population (PO. The first one, selected those plants whose S1 progenies exhibited higher inbreeding depression (≥65% on forage production; the second one, selected the plants of the PO that did not produce S1 seed; the last one, consisted on traditional phenotypic selection of PO plants with higher forage yield (15% superior. The elite were manually

  7. Vertical diffuse attenuation coefficient (Kd) based optical ...

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    The optical classification of the different water types provides vital input for studies related to primary productivity, water clarity and determination of euphotic depth. Image data of the IRS-. P3 MOS-B, for Path 90 of 27th February, 1998 was used for deriving vertical diffuse attenuation coefficient (Kd) and an optical ...

  8. Coefficient Omega Bootstrap Confidence Intervals: Nonnormal Distributions

    Science.gov (United States)

    Padilla, Miguel A.; Divers, Jasmin

    2013-01-01

    The performance of the normal theory bootstrap (NTB), the percentile bootstrap (PB), and the bias-corrected and accelerated (BCa) bootstrap confidence intervals (CIs) for coefficient omega was assessed through a Monte Carlo simulation under conditions not previously investigated. Of particular interests were nonnormal Likert-type and binary items.…

  9. Tracking Time-Varying Coefficient-Functions

    DEFF Research Database (Denmark)

    Nielsen, Henrik Aalborg; Nielsen, Torben Skov; Joensen, Alfred K.

    1999-01-01

    A conditional parametric ARX-model is an ARX-model in which the parameters re replaced by smooth functions of an, possibly multivariate, externalinput signal. These functions are called coefficient functions is suggested. Essentially, in its most simple form, this method is a combination of recur...

  10. Ideal related K-theory with coefficients

    DEFF Research Database (Denmark)

    Eilers, Soren; Restorff, Gunnar; Ruiz, Efren

    2017-01-01

    In this paper, we define an invariant, which we believe should be the substitute for total K-theory in the case when there is one distinguished ideal. Moreover, some diagrams relating the new groups to the ordinary K-groups with coefficients are constructed. These diagrams will in most cases help...

  11. Regularity of the Interband Light Absorption Coefficient

    Indian Academy of Sciences (India)

    In this paper we consider the interband light absorption coefficient (ILAC), in a symmetric form, in the case of random operators on the -dimensional lattice. We show that the symmetrized version of ILAC is either continuous or has a component which has the same modulus of continuity as the density of states.

  12. Prediction of longitudinal dispersion coefficient using multivariate ...

    Indian Academy of Sciences (India)

    Keywords. River water quality; artificial neural network; longitudinal dispersion coefficient; pollution transmission ... Error indices showed that MARS model has suitable performanceand is more accurate compared to multi-layer neural network model and empirical formulas. Results ofthe Gamma test and MARS model ...

  13. Friction Coefficient Determination by Electrical Resistance Measurements

    Science.gov (United States)

    Tunyagi, A.; Kandrai, K.; Fülöp, Z.; Kapusi, Z.; Simon, A.

    2018-01-01

    A simple and low-cost, DIY-type, Arduino-driven experiment is presented for the study of friction and measurement of the friction coefficient, using a conductive rubber cord as a force sensor. It is proposed for high-school or college/university-level students. We strongly believe that it is worthwhile planning, designing and performing Arduino…

  14. Molar extinction coefficients of some fatty acids

    DEFF Research Database (Denmark)

    Sandhu, G.K.; Singh, K.; Lark, B.S.

    2002-01-01

    ) and stearic acid (C18H36O2), has been measured at the photon energies 81, 356, 511, 662, 1173 and 1332 keV. Experimental values for the molar extinction coefficient, the effective atomic number and the electron density have been derived and compared with theoretical calculations. There is good agreement...

  15. Effective stress coefficient for uniaxial strain condition

    DEFF Research Database (Denmark)

    Alam, M.M.; Fabricius, I.L.

    2012-01-01

    one dimensional rock mechanical deformation. We further investigated the effect of boundary condition on the stress dependency of effective stress coefficient and discussed its application in reservoir study. As stress field in the reservoirs are most unlikely to be hydrostatic, effective stress...... determined under uniaxial strain condition will be more relevant in reservoir studies. Copyright 2012 ARMA, American Rock Mechanics Association....

  16. Modelling of power-reactivity coefficient measurement

    International Nuclear Information System (INIS)

    Strmensky, C.; Petenyi, V.; Jagrik, J.; Minarcin, M.; Hascik, R.; Toth, L.

    2005-01-01

    Report describes results of modeling of power-reactivity coefficient analysis on power-level. In paper we calculate values of discrepancies arisen during transient process. These discrepancies can be arisen as result of experiment evaluation and can be caused by disregard of 3D effects on neutron distribution. The results are critically discussed (Authors)

  17. Pressure-viscosity coefficient of biobased lubricants

    Science.gov (United States)

    Film thickness is an important tribological property that is dependent on the combined effect of lubricant properties, material property of friction surfaces, and the operating conditions of the tribological process. Pressure-viscosity coefficient (PVC) is one of the lubricant properties that influe...

  18. Bayesian Meta-Analysis of Coefficient Alpha

    Science.gov (United States)

    Brannick, Michael T.; Zhang, Nanhua

    2013-01-01

    The current paper describes and illustrates a Bayesian approach to the meta-analysis of coefficient alpha. Alpha is the most commonly used estimate of the reliability or consistency (freedom from measurement error) for educational and psychological measures. The conventional approach to meta-analysis uses inverse variance weights to combine…

  19. Infinite matrices, wavelet coefficients and frames

    Directory of Open Access Journals (Sweden)

    N. A. Sheikh

    2004-01-01

    Full Text Available We study the action of A on f∈L2(ℝ and on its wavelet coefficients, where A=(almjklmjk is a double infinite matrix. We find the frame condition for A-transform of f∈L2(ℝ whose wavelet series expansion is known.

  20. Rate coefficient for the reaction N + NO

    Science.gov (United States)

    Fox, J. L.

    1994-01-01

    Evidence has been advanced that the rate coefficient for the reaction N + NO right arrow N2 + O has a small positive temperature dependence at the high temperatures (900 to 1500 K) that prevail in the terrestrial middle and upper thermosphere by Siskind and Rusch (1992), and at the low temperatures (100 to 200 K) of the Martian lower thermosphere by Fox (1993). Assuming that the rate coefficient recommended by the Jet Propulsion Laboratory evaluation (DeMore et al., 1992) is accurate at 300 K, we derive here the low temperature value of the activation energy for this reaction and thus the rate coefficient that best fits the Viking 1 measured NO densities. We find that the fit is acceptable for a rate coefficient of about 1.3 x 10(exp -10)(T/300)(exp 0.5)exp(-400/T) and better for a value of about 2.5 x 10(exp -10)(T/300)(exp 0.5)exp(-600/T)cu cm/s.

  1. Cohomology with coefficients for operadic coalgebras

    Indian Academy of Sciences (India)

    Corepresentations of a coalgebra over a quadratic operad are defined, and various characterizations of them are given. Cohomology of such an operadic coalgebra with coefficients in a corepresentation is then studied. Author Affiliations. Anita Majumdar1 Donald Yau2. Department of Mathematics, Indian Institute of ...

  2. Problems on Divisibility of Binomial Coefficients

    Science.gov (United States)

    Osler, Thomas J.; Smoak, James

    2004-01-01

    Twelve unusual problems involving divisibility of the binomial coefficients are represented in this article. The problems are listed in "The Problems" section. All twelve problems have short solutions which are listed in "The Solutions" section. These problems could be assigned to students in any course in which the binomial theorem and Pascal's…

  3. Power coefficient anomaly in Joyo, (2)

    International Nuclear Information System (INIS)

    Ishikawa, Makoto; Yamashita, Yoshioki; Sasaki, Makoto; Nara, Yoshihiko.

    1981-12-01

    In this report, the presumption about the mechanism having caused the power coefficient anomaly in Joyo during the 75 MW power-raising test in 1979 is described. After the previous report, the new information about the results of the post-irradiation examination and the analysis of the power coefficient of Joyo were able to be obtained. From these information, the mechanism of causing the anomaly was presumed as follows. In 50 MW operation, the fuel burnup reached about 10,000 MWD/ton at the end of second cycle, and produced fission gas was almost retained in fuel pellets. When the power was raised from 50 MW to 75 MW for the first time, the fission gas began to be released when 50 MW was somewhat exceeded. The fission gas release caused the temperature rise and cracking of fuel pellets, and elongated fuel stack length abruptly. These phenomena induced to enlarge the fuel expansion reactivity effect and Doppler reactivity effect, and caused the anomalous behavior of power coefficient. After reaching 75 MW, the fuel stack length did not respond normally to reactor power change, and the magnitude of power coefficient became smaller. The reactivity was lost considerably from the core after the anomaly. (Kako, I.)

  4. A Graphical Interpretation of Probit Coefficients.

    Science.gov (United States)

    Becker, William E.; Waldman, Donald M.

    1989-01-01

    Contends that, when discrete choice models are taught, particularly the probit model, it is the method rather than the interpretation of the results that is emphasized. This article provides a graphical technique for interpretation of an estimated probit coefficient that will be useful in statistics and econometrics courses. (GG)

  5. Vertical diffuse attenuation coefficient (Kd) based optical ...

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    mary production and diffuse attenuation coeffi- cient (Austin 1981; Sathyendranath et al 2000). The Indian IRS-P3 ... oceanic and coastal production of phytoplank- ton (Tyler 1975; Pennock and Sharp 1986). As a result basic ... cient to the plant pigment content. The term dif- fuse attenuation coefficient, most commonly used.

  6. Recursive harmonic analysis for computing Hansen coefficients

    Science.gov (United States)

    Adel Sharaf, Mohamed; Hassan Selim, Hadia

    2010-12-01

    We report on a simple pure numerical method developed for computing Hansen coefficients by using a recursive harmonic analysis technique. The precision criteria of the computations are very satisfactory and provide materials for computing Hansen's and Hansen's like expansions, and also to check the accuracy of some existing algorithms.

  7. An alternative coefficient for sound absorption

    NARCIS (Netherlands)

    Wijnant, Ysbrand H.; Kuipers, E.R.; de Boer, Andries; Sas, P; Jonckheere, S.; Moens, D.

    2013-01-01

    The acoustic absorption coefficient is a number that indicates which fraction of the incident acoustic power impinging on a surface is being absorbed. The incident acoustic power is obtained by spatial integration of the incident intensity, which is (classically) defined as the time-averaged

  8. Skidding Coefficients on an Alluvial Soil

    Science.gov (United States)

    W. N. Darwin

    1965-01-01

    The Southern Hardwoods Laboratory is studying the influence of ground conditions and load characteristics on the performance of skidding vehicles in southern bottom lands. The exploratory test was aimed at evaluating the effects of bark on skidding coefficients, but it also yielded information on other log characteristics and on effects of soil moisture.

  9. Effective stress coefficient for uniaxial strain condition

    DEFF Research Database (Denmark)

    Alam, Mohammad Monzurul; Fabricius, Ida Lykke

    2012-01-01

    The effective stress coefficient, introduced by Biot, is used for predicting effective stress or pore pressure in the subsurface. It is not a constant value. It is different for different types of sediment and it is stress dependent. We used a model, based on contact between the grains to describe...

  10. Determination of the convective heat transfer coefficient

    NARCIS (Netherlands)

    Spierings, D.; Bosman, F.; Peters, T.; Plasschaert, F.

    The value of the convective heat transfer coefficient (htc) is determined under different loading conditions by using a computer aided method. The thermal load has been applied mathematically as well as experimentally to the coronal surface of an axisymmetric tooth model. To verify the assumptions

  11. Transport coefficients in high-temperature ionized air flows with electronic excitation

    Science.gov (United States)

    Istomin, V. A.; Oblapenko, G. P.

    2018-01-01

    Transport coefficients are studied in high-temperature ionized air mixtures using the modified Chapman-Enskog method. The 11-component mixture N2/N2+/N /N+/O2/O2+/O /O+/N O /N O+/e- , taking into account the rotational and vibrational degrees of freedom of molecules and electronic degrees of freedom of both atomic and molecular species, is considered. Using the PAINeT software package, developed by the authors of the paper, in wide temperature range calculations of the thermal conductivity, thermal diffusion, diffusion, and shear viscosity coefficients for an equilibrium ionized air mixture and non-equilibrium flow conditions for mixture compositions, characteristic of those in shock tube experiments and re-entry conditions, are performed. For the equilibrium air case, the computed transport coefficients are compared to those obtained using simplified kinetic theory algorithms. It is shown that neglecting electronic excitation leads to a significant underestimation of the thermal conductivity coefficient at temperatures higher than 25 000 K. For non-equilibrium test cases, it is shown that the thermal diffusion coefficients of neutral species and the self-diffusion coefficients of all species are strongly affected by the mixture composition, while the thermal conductivity coefficient is most strongly influenced by the degree of ionization of the flow. Neglecting electronic excitation causes noticeable underestimation of the thermal conductivity coefficient at temperatures higher than 20 000 K.

  12. Characterization of skin friction coefficient, and relationship to stratum corneum hydration in a normal Chinese population.

    Science.gov (United States)

    Zhu, Y H; Song, S P; Luo, W; Elias, P M; Man, M Q

    2011-01-01

    Studies have demonstrated that some cutaneous biophysical properties vary with age, gender and body sites. However, the characteristics of the skin friction coefficient in different genders and age groups have not yet been well established. In the present study, we assess the skin friction coefficient in a larger Chinese population. A total of 633 subjects (300 males and 333 females) aged 0.15-79 years were enrolled. A Frictiometer FR 770 and Corneometer CM 825 (C&K MPA 5) were used to measure the skin friction coefficient and stratum corneum hydration, respectively, on the dorsal surface of the hand, the forehead and the canthus. In the females, the maximum skin friction coefficients on both the canthus and the dorsal hand skin were observed around the age of 40 years. In the males, the skin friction coefficient on the dorsal hand skin gradually increased from 0 to 40 years of age, and changed little afterward. Skin friction coefficients on some body sites were higher in females than in age-matched males in some age groups. On the canthus and the dorsal hand skin of females, a positive correlation was found between skin friction coefficient and stratum corneum hydration (p friction coefficient was positively correlated with stratum corneum hydration on the forehead and the dorsal hand skin (p friction coefficient varies with age, gender and body site, and positively correlates with stratum corneum hydration on some body sites. Copyright © 2010 S. Karger AG, Basel.

  13. Analytical model of reactive transport processes with spatially variable coefficients.

    Science.gov (United States)

    Simpson, Matthew J; Morrow, Liam C

    2015-05-01

    Analytical solutions of partial differential equation (PDE) models describing reactive transport phenomena in saturated porous media are often used as screening tools to provide insight into contaminant fate and transport processes. While many practical modelling scenarios involve spatially variable coefficients, such as spatially variable flow velocity, v(x), or spatially variable decay rate, k(x), most analytical models deal with constant coefficients. Here we present a framework for constructing exact solutions of PDE models of reactive transport. Our approach is relevant for advection-dominant problems, and is based on a regular perturbation technique. We present a description of the solution technique for a range of one-dimensional scenarios involving constant and variable coefficients, and we show that the solutions compare well with numerical approximations. Our general approach applies to a range of initial conditions and various forms of v(x) and k(x). Instead of simply documenting specific solutions for particular cases, we present a symbolic worksheet, as supplementary material, which enables the solution to be evaluated for different choices of the initial condition, v(x) and k(x). We also discuss how the technique generalizes to apply to models of coupled multispecies reactive transport as well as higher dimensional problems.

  14. Measurements of the Drag Coefficient of Simulated Micrometeoroids

    Science.gov (United States)

    DeLuca, M.; Munsat, T.; Sternovsky, Z.

    2017-12-01

    The dust accelerator facility operated at the University of Colorado is used to simulate meteoric ablation, including measuring the ionization efficiency over a wide range of velocities (e.g., DeLuca et al., Planet. Space Sci., submitted, 2017). This presentation reports on the most recent experimental measurements of the drag coefficient that determines the particles' slowdown from their frictional interaction with the atmosphere. The measurements indicate that meteors experience considerably more slowdown than usually assumed. The simulated meteors consisted of submicron sized aluminum particles shot into an air chamber held at 200 mTorr pressure at velocities between 1 - 10 km/s using the dust accelerator and meteor ablation facility. The slowdown is calculated from precise timing measurements made using pickup tube detectors placed upstream and near the entrance to the air chamber, and an impact detector inside the air chamber at the downstream end of the chamber. Supporting modeling calculations show that the particles have little or no mass loss during their interaction with air and thus constant radius can be assumed. Preliminary results for the drag coefficient calculated from these timing measurements reveal that the aluminum particles have a drag coefficient of 1.51 ± 0.24 in air, which is higher than typically assumed in meteoric ablation models (usually 0.5 to 1), indicating that meteors may experience more air drag than previously assumed. More detailed measurements over a wider parameter range are underway.

  15. Determination of kinetic coefficients for some selected wastes (research note)

    International Nuclear Information System (INIS)

    Qaisi, M. K.; Samaneh, T; Zoubi, O.

    1999-01-01

    This study was undertaken to estimate the kinetic constants of different wastes experimentally using laboratory scale reactors. three wastes were close n; domestic, brewery, and whey. The resulting data for the three wastes fit well both sludge growth and oxygen utilization kinetic models with high correlation coefficients, and were found to be within the reported values by others. The study shows that oxygen utilization rate was higher for domestic than those for the two other wastes. Also it shows that suspended growth treating brewery and whey wastes are more sensitive to any increase in BOD 5 than that treating domestic wastewater. (authors). 7 refs., 7 figs., 5 tabs

  16. Weyl q-coefficients for uq(3) and Racah q -coefficients for suq(2)

    International Nuclear Information System (INIS)

    Asherova, R.M.; Smirnov, Yu.F.; Tolstoy, V.N.

    1996-01-01

    With the aid of the projection-operator technique, the general analytic expression for the elements of the matrix that relates the U and T bases of an arbitrary finite-dimensional irreducible representation of the uq(3) quantum algebra (Weyl q-coefficients) is obtained for the case where the deformation parameter q is not equal to a square root of unity. The procedure for resummation of q-factorial expressions is used to prove that, modulo phase factors, these Weyl q-coefficients coincide with Racah q-coefficients for the suq(2) quantum algebra. It is also shown that, on the basis of one general formula, the q-analogs of all known general analytic expressions for the 6j symbols (and Racah coefficients) of the Lie algebras of the angular momentum can be obtained by using this resummation procedure. The symmetry properties of these q coefficients are discussed. The result is formulated in the following way: the general formulas for the q-6j symbols (Racah q-coefficients) of the suq(2) quantum algebra are obtained from the general formulas for the conventional 6j symbols (Racah coefficients) of the su(2) Lie algebra by replacing directly all factorials with q-factorials, the symmetry properties of the q-6j symbols being completely coincident with the symmetry properties of the conventional 6j symbols

  17. Variations of Roughness Coefficients with Flow Depth of Grassed Swale

    Science.gov (United States)

    Mustaffa, N.; Ahmad, N. A.; Razi, M. A. M.

    2016-07-01

    Grassed swales are the best management practice (BMP), which has been widely used to reduce the peak flow, reduce water pollution through vegetated filtration, and improve the groundwater recharge. Universiti Tun Hussein Onn Malaysia (UTHM) is using the approach of grassed swales recommended by the Department of Irrigation and Drainage Malaysia (DID) for reducing the risk of flooding and controlling the water pollution. This paper investigates the variations of roughness coefficients with the flow depth of grassed swales in the campus of UTHM. Fieldwork was carried out on the grassed swale to collect the hydraulic data, which including the levelling work, measuring the flow depth and flow velocity of the swale. The flow depth of swale was taken at three points divided along the width of swale and the flow velocity is captured three times at each of the point. The variations of roughness coefficients of grassed swales are presented in Manning's equation, and the results reveal that the n value increases with the increasing of flow depth. Manning's coefficient value found in this study is in the range of 0.110 to 0.756, which are higher than the value proposed by the Urban Stormwater Management Manual for Malaysia (MSMA). The relationships of flow depth and velocity at each section of the swale are portrayed in graphs, which show that the velocity increases with the decreasing of flow depth. The outcomes of this study can be concluded that the variation of Manning's coefficient value is influenced by the swale profile, flow depth, flow velocity, and as well as the vegetation used in the grassed swale concerned.

  18. Instability analysis and drag coefficient prediction on a swept RAE2822 wing with constant lift coefficient

    Directory of Open Access Journals (Sweden)

    Zhenrong JING

    2017-06-01

    Full Text Available Swept wing is widely used in civil aircraft, whose airfoil is chosen, designed and optimized to increase the cruise speed and decrease the drag coefficient. The parameters of swept wing, such as sweep angle and angle of attack, are determined according to the cruise lift coefficient requirement, and the drag coefficient is expected to be predicted accurately, which involves the instability characteristics and transition position of the flow. The pressure coefficient of the RAE2822 wing with given constant lift coefficient is obtained by solving the three-dimensional Navier-Stokes equation numerically, and then the mean flow is calculated by solving the boundary layer (BL equation with spectral method. The cross-flow instability characteristic of boundary layer of swept wing in the windward and leeward is analyzed by linear stability theory (LST, and the transition position is predicted by eN method. The drag coefficient is numerically predicted by introducing a laminar/turbulent indicator. A simple approach to calculate the lift coefficient of swept wing is proposed. It is found that there is a quantitative relationship between the angle of attack and sweep angle when the lift coefficient keeps constant; when the angle of attack is small, the flow on the leeward of the wing is stable. when the angle of attack is larger than 3°, the flow becomes unstable quickly; with the increase of sweep angle or angle of attack the disturbance on the windward becomes more unstable, leading to the moving forward of the transition position to the leading edge of the wing; the drag coefficient has two significant jumping growth due to the successive occurrence of transition in the windward and the leeward; the optimal range of sweep angle for civil aircraft is suggested.

  19. Meromorphic univalent function with negative coefficient

    Directory of Open Access Journals (Sweden)

    A. Dernek

    1994-01-01

    Full Text Available Let Mn be the classes of regular functions f(z=z−1+a0+a1z+… defined in the annulus 00, (n∈ℕ0, where I0f(z=f(z, If(z=(z−1−z(z−1−2∗f(z, Inf(z=I(In−1f(z, and ∗ is the Hadamard convolution. We denote by Γn=Mn⋃Γ, where Γ denotes the class of functions of the form f(z=z−1+∑k=1∞|ak|zk. We obtained that relates the modulus of the coefficients to starlikeness for the classes Mn and Γn, and coefficient inequalities for the classes Γn.

  20. Head-wave coefficients in anisotropic media

    Science.gov (United States)

    Chapman, Chris

    2018-03-01

    Reflections and transmissions from interfaces can generate head waves. Although the kinematic properties of head waves are modelled simply using ray concepts, the dynamic properties require an extension of ray theory or the use of wave theory. Head waves are important in exploration and crustal seismology as they indicate the existence of an interface and the velocity of the generating wave. Head waves have been described in the literature for isotropic media but the extension to anisotropic media seems to be lacking. The expressions for the head-wave coefficients using ray concepts or wave theory differ, and their equality is not obvious. This paper extends the theory for head-wave coefficients to anisotropic media using both ray theory and wave theory, and generalizes the proof of equality of the two methods. Simple numerical examples confirm this equality and indicate how the head-wave results can be calculated in anisotropic media and included in a ray-tracing algorithm.

  1. Gate Control Coefficient Effect on CNFET Characteristic

    International Nuclear Information System (INIS)

    Sanudin, Rahmat; Ma'Radzi, Ahmad Alabqari; Nayan, Nafarizal

    2009-01-01

    The development of carbon nanotube field-effect transistor (CNFET) as alternative to existing transistor technology has long been published and discussed. The emergence of this device offers new material and structure in building a transistor. This paper intends to do an analysis of gate control coefficient effect on CNFET performance. The analysis is based on simulation study of current-voltage (I-V) characteristic of ballistic CNFET. The simulation study used the MOSFET-like CNFET mathematical model to establish the device output characteristic. Based on the analysis of simulation result, it is found that the gate control coefficient contributes to a significant effect on the performance of CNFET. The result also shown the parameter could help to improve the device performance in terms of its output and response as well. Nevertheless, the characteristic of the carbon nanotube that acts as the channel is totally important in determining the performance of the transistor as a whole.

  2. Doppler coefficient measurements in Zebra Core 5

    International Nuclear Information System (INIS)

    Baker, A.R.; Wheeler, R.C.

    1965-11-01

    Measurements using a central hot loop in Zebra Core 5 are described. Results are given for the Doppler coefficients found in a number of assemblies with PuO 2 and 16% PuO 2 /84% depleted UO 2 pins, loaded with different combinations of steel, sodium or void pins. The mixed oxide results are in general about 20% more negative than was calculated using the FD2 data set, but agreement is good if the plutonium contributions in the calculations are omitted. The small positive Doppler coefficient calculated for Pu239 was not observed, and two measurements indicated instead a small negative effect. The Doppler effect in the mixed oxide systems was found to vary approximately as 1/T. The results from the empty loop and non-fissile assemblies indicate either a small negative Doppler effect in steel or alternatively the presence of an unexplained expansion effect. (author)

  3. The coefficient of friction, particularly of ice

    International Nuclear Information System (INIS)

    Mills, Allan

    2008-01-01

    The static and dynamic coefficients of friction are defined, and values from 0.3 to 0.6 are quoted for common materials. These drop to about 0.15 when oil is added as a lubricant. Water ice at temperatures not far below 0 °C is remarkable for low coefficients of around 0.05 for static friction and 0.04–0.02 for dynamic friction, but these figures increase as the temperature diminishes. Reasons for the slipperiness of ice are summarized, but they are still not entirely clear. One hypothesis suggests that it is related to the transient formation of a lubricating film of liquid water produced by frictional heating. If this is the case, some composition melting a little above ambient temperatures might provide a skating rink that did not require expensive refrigeration. Various compositions have been tested, but an entirely satisfactory material has yet to be found

  4. Analytical expressions for the electron backscattering coefficient

    International Nuclear Information System (INIS)

    August, H.J.; Wernisch, J.

    1989-01-01

    Several analytical expressions for the electron backscattering coefficient for massive homogeneous samples are compared with experimental data, directing special attention to the dependence of this quantity on the electron acceleration energy. It is shown that this dependence generally cannot be neglected. The expression proposed by Hunger and Kuechler turns out to be better than that of Love and Scott, although even the better formula can be slightly improved by a small modification. (author)

  5. Effective stress coefficient for uniaxial strain condition

    DEFF Research Database (Denmark)

    Alam, M.M.; Fabricius, I.L.

    2012-01-01

    The effective stress coefficient, introduced by Biot, is used for predicting effective stress or pore pressure in the subsurface. It is not a constant value. It is different for different types of sediment and it is stress dependent. We used a model, based on contact between the grains to describ...... determined under uniaxial strain condition will be more relevant in reservoir studies. Copyright 2012 ARMA, American Rock Mechanics Association....

  6. Varying coefficients model with measurement error.

    Science.gov (United States)

    Li, Liang; Greene, Tom

    2008-06-01

    We propose a semiparametric partially varying coefficient model to study the relationship between serum creatinine concentration and the glomerular filtration rate (GFR) among kidney donors and patients with chronic kidney disease. A regression model is used to relate serum creatinine to GFR and demographic factors in which coefficient of GFR is expressed as a function of age to allow its effect to be age dependent. GFR measurements obtained from the clearance of a radioactively labeled isotope are assumed to be a surrogate for the true GFR, with the relationship between measured and true GFR expressed using an additive error model. We use locally corrected score equations to estimate parameters and coefficient functions, and propose an expected generalized cross-validation (EGCV) method to select the kernel bandwidth. The performance of the proposed methods, which avoid distributional assumptions on the true GFR and residuals, is investigated by simulation. Accounting for measurement error using the proposed model reduced apparent inconsistencies in the relationship between serum creatinine and GFR among different clinical data sets derived from kidney donor and chronic kidney disease source populations.

  7. Protein diffusion coefficients determined by macroscopic-gradient Rayleigh interferometry and dynamic light scattering.

    Science.gov (United States)

    Annunziata, Onofrio; Buzatu, Daniela; Albright, John G

    2005-12-20

    Dynamic light scattering (DLS) is extensively used for measuring macromolecule diffusion coefficients. Contrary to classical techniques based on macroscopic concentration gradients, DLS probes microscopic fluctuations in concentration. DLS accuracy and its concordance with macroscopic-gradient techniques remains an outstanding important issue. We measured lysozyme diffusion coefficients in aqueous salt using both DLS and Rayleigh interferometry, a highly accurate macroscopic-gradient technique. The precision of our results is unprecedented. We find that our DLS values were systematically 2% higher than interferometry values. We believe that our interferometric measurements have produced the most accurate diffusion data ever reported for a protein, providing a new standard for quality control of DLS measurements. Furthermore, by interferometry, we have determined the whole diffusion coefficient matrix required for rigorously describing lysozyme-salt coupled diffusion. For the first time, we experimentally demonstrate that DLS does not provide the protein diffusion coefficient but one eigenvalue of the diffusion coefficient matrix.

  8. Thermal conductivity coefficients of water and heavy water in the liquid state up to 3700C

    International Nuclear Information System (INIS)

    Le Neindre, B.; Bury, P.; Tufeu, R.; Vodar, B.

    1976-01-01

    The thermal conductivity coefficients of water and heavy water of 99.75 percent isotopic purity were measured using a coaxial cylinder apparatus, covering room temperature to their critical temperatures, and pressures from 1 to 500 bar for water, and from 1 to 1000 bar for heavy water. Following the behavior of the thermal conductivity coefficient of water, which shows a maximum close to 135 0 C, the thermal conductivity coefficient of heavy water exhibits a maximum near 95 0 C and near saturation pressures. This maximum is displaced to higher temperatures when the pressure is increased. Under the same temperature and pressure conditions the thermal conductivity coefficient of heavy water was lower than for water. The pressure effect was similar for water and heavy water. In the temperature range of our experiments, isotherms of thermal conductivity coefficients were almost linear functions of density

  9. Field estimation of the utilization coefficient of added inorganic nitrogen by sugar-beets

    International Nuclear Information System (INIS)

    Lindemann, Y.; Guiraud, G.; Christmann, J.; Auge, G.

    1981-07-01

    Fertilization with mineral nitrogen labelled with the 15 isotope permits, in the crop, the estimation of both: - the real utilization coefficient of N fertilizer, - the uptake of the available N issued from organic matter. In 1979, such an experiment was carried out on sugar beet in Beauce on a long term field experiment including 7 N.P.K. treatments with 4 repetitions. Each plot was divided into 2 parts to constitute a treatment N=0 for the estimation of the apparent utilization coefficient. In addition, 4 microplots (size: 8 m 2 ) received a labelled fertilizer for the measurement of the actual coefficients. The results obtained show the incoherence of the apparent coefficients, which are higher than 100%. The real coefficients are from 40 to 80%. Thus, the balance sheet for the input and output of mineral nitrogen is established precisely. The gross mineralization can be much more important than the net mineralization [fr

  10. Radionuclide transfer to animal products: revised recommended transfer coefficient values

    International Nuclear Information System (INIS)

    Howard, B.J.; Beresford, N.A.; Barnett, C.L.; Fesenko, S.

    2009-01-01

    A compilation has been undertaken of data which can be used to derive animal product transfer coefficients for radionuclides, including an extensive review of Russian language information. The resultant database has been used to provide recommended transfer coefficient values for a range of radionuclides to (i) cow, sheep and goat milk, (ii) meat (muscle) of cattle, sheep, goats, pigs and poultry and (iii) eggs. The values are used in a new IAEA handbook on transfer parameters which replaces that referred to as 'TRS 364'. The paper outlines the approaches and procedures used to identify and collate data, and assumptions used. There are notable differences between the TRS 364 'expected' values and the recommended values in the revised Handbook from the new database. Of the recommended values, three milk values are at least an order of magnitude higher than the TRS 364 values (Cr, Pu (cow) Pu (sheep)) and one milk value is lower (Ni (cow)). For meat, four values (Am, Cd, Sb (beef) I (pork)) are at least an order of magnitude higher than the TRS 364 values and eight values are at least an order of magnitude lower (Ru, Pu (beef), Ru, Sr, Zn (sheep), Ru, Sr (pork), Mn (poultry)). Many data gaps remain

  11. Comparison of field-measured radon diffusion coefficients with laboratory-measured coefficients

    International Nuclear Information System (INIS)

    Lepel, E.A.; Silker, W.B.; Thomas, V.W.; Kalkwarf, D.R.

    1983-04-01

    Experiments were conducted to compare radon diffusion coefficients determined for 0.1-m depths of soils by a steady-state method in the laboratory and diffusion coefficients evaluated from radon fluxes through several-fold greater depths of the same soils covering uranium-mill tailings. The coefficients referred to diffusion in the total pore volume of the soils and are equivalent to values for the quantity, D/P, in the Generic Environmental Impact Statement on Uranium Milling prepared by the US Nuclear Regulatory Commission. Two soils were tested: a well-graded sand and an inorganic clay of low plasticity. For the flux evaluations, radon was collected by adsorption on charcoal following passive diffusion from the soil surface and also from air recirculating through an aluminum tent over the soil surface. An analysis of variance in the flux evaluations showed no significant difference between these two collection methods. Radon diffusion coefficients evaluated from field data were statistically indistinguishable, at the 95% confidence level, from those measured in the laboratory; however, the low precision of the field data prevented a sensitive validation of the laboratory measurements. From the field data, the coefficients were calculated to be 0.03 +- 0.03 cm 2 /s for the sand cover and 0.0036 +- 0.0004 cm 2 /s for the clay cover. The low precision in the coefficients evaluated from field data was attributed to high variation in radon flux with time and surface location at the field site

  12. Static coefficient of friction between stainless steel and PMMA used in cemented hip and knee implants.

    Science.gov (United States)

    Nuño, N; Groppetti, R; Senin, N

    2006-11-01

    Design of cemented hip and knee implants, oriented to improve the longevity of artificial joints, is largely based on numerical models. The static coefficient of friction between the implant and the bone cement is necessary to characterize the interface conditions in these models and must be accurately provided. The measurement of this coefficient using a repeatable and reproducible methodology for materials used in total hip arthroplasty is missing from the literature. A micro-topographic surface analysis characterized the surfaces of the specimens used in the experiments. The coefficient of friction between stainless steel and bone cement in dry and wet conditions using bovine serum was determined using a prototype computerized sliding friction tester. The effects of surface roughness (polished versus matt) and of contact pressure on the coefficient of friction have also been investigated. The serum influences little the coefficient of friction for the matt steel surface, where the mechanical interactions due to higher roughness are still the most relevant factor. However, for polished steel surfaces, the restraining effect of proteins plays a very relevant role in increasing the coefficient of friction. When the coefficient of friction is used in finite element analysis, it is used for the debonded stem-cement situation. It can thus be assumed that serum will propagate between the stem and the cement mantle. The authors believe that the use of a static coefficient of friction of 0.3-0.4, measured in the present study, is appropriate in finite element models.

  13. Low-Cost Design of an FIR Filter by Using a Coefficient Mapping Method

    Directory of Open Access Journals (Sweden)

    Ming-Chih Chen

    2013-01-01

    Full Text Available This work presents a novel coefficient mapping method to reduce the area cost of the finite impulse response (FIR filter design, especially for optimizing its coefficients. Being capable of reducing the area cost and improving the filter performance, the proposed mapping method consists of four steps: quantization of coefficients, import of parameters, constitution of prime coefficients with parameters, and constitution of residual coefficients with prime coefficients. Effectiveness of the proposed coefficient mapping method is verified by selecting the 48-tap filter of IS-95 code division multiple access (CDMA standard as the benchmark. Experimental results indicate that the proposed design with canonical signed digit (CSD coefficients can operate at 86 MHz with an area of 241,813 um2, leading to a throughput rate of 1,382 Mbps. Its ratio of throughput/area is 5,715 Kbps/um2, yielding a higher performance than that of previous designs. In summary, the proposed design reduces 5.7% of the total filter area, shortens 25.7% of the critical path delay, and improves 14.8% of the throughput/area by a value over that of the best design reported before.

  14. On separation of exchange term from the coefficient of the ...

    Indian Academy of Sciences (India)

    Abstract. The purpose of this analysis is to introduce the separated exchange coefficient and to graphically investigate it. This coefficient, depending on the electromagnetic constant plus two coefficients of the electromechanical and magnetomechanical couplings, form the coefficient of magnetoelectromechanical coupling ...

  15. Determination of coefficient matrices for ARMA model

    International Nuclear Information System (INIS)

    Tran Dinh Tri.

    1990-10-01

    A new recursive algorithm for determining coefficient matrices of ARMA model from measured data is presented. The Yule-Walker equations for the case of ARMA model are derived from the ARMA innovation equation. The recursive algorithm is based on choosing appropriate form of the operator functions and suitable representation of the (n+1)-th order operator functions according to ones with the lower order. Two cases, when the order of the AR part is equal to one of the MA part, and the optimal case, were considered. (author) 5 refs

  16. Kinetic coefficients in isotopically disordered crystals

    International Nuclear Information System (INIS)

    Zhernov, Arkadii P; Inyushkin, Alexander V

    2002-01-01

    Peculiarities of the behavior of kinetic coefficients, like thermal conductivity, electric conductivity, and thermoelectric power, in isotopically disordered materials are reviewed in detail. New experimental and theoretical results on the isotope effects in the thermal conductivity of diamond, Ge, and Si semiconductors are presented. The suppression effect of phonon-drag thermopower in the isotopically disordered Ge crystals is discussed. The influence of dynamic and static crystal lattice deformations on the electric conductivity of metals as well as on the ordinary phonon spectrum deformations is considered. (reviews of topical problems)

  17. Peltier coefficient measurement in a thermoelectric module

    International Nuclear Information System (INIS)

    Garrido, Javier; Casanovas, Alejandro; Chimeno, José María

    2013-01-01

    A new method for measuring the Peltier coefficient in a thermocouple X/Y based on the energy balance at the junction has been proposed recently. This technique needs only the hot and cold temperatures of a thermoelectric module when an electric current flows through it as the operational variables. The temperature evolutions of the two module sides provide an evident and accurate idea of the Peltier effect. From these temperatures, the heat transfer between the module and the ambient is also evaluated. The thermoelectric phenomena are described in the framework of an observable theory. Based on this procedure, an experiment is presented for a university teaching laboratory at the undergraduate level. (paper)

  18. Quenching of Einstein-coefficients by photons

    International Nuclear Information System (INIS)

    Aumayr, F.; Lee, W.; Skinner, C.H.; Suckewer, S.

    1991-03-01

    Experimental evidence is presented for the change of Einstein's A- coefficients for spontaneous transitions from the upper laser level of argon ion laser discharge due to the presence of the high- intensity laser flux. To demonstrate that this quenching effect cannot be attributed to a reduction in self-absorption of the strong spontaneous emission line, absorption and line profile measurements have been performed. Computer modelling of the reduction of self absorption due to Rabi splitting also indicated that this effect is too small to explain the observed quenching of spontaneous line emissions. 13 refs., 11 figs

  19. Effective Diffusion Coefficients in Coal Chars

    DEFF Research Database (Denmark)

    Johnsson, Jan Erik; Jensen, Anker

    2001-01-01

    Knowledge of effective diffusion coefficients in char particles is important when interpreting experimental reactivity measurements and modeling char combustion or NO and N2O reduction. In this work, NO and N2O reaction with a bituminous coal char was studied in a fixed-bed quartz glass reactor....... In the case of strong pore diffusion limitations, the error in the interpretation of experimental results using the mean pore radius could be a factor of 5 on the intrinsic rate constant. For an average coal char reacting with oxygen at 1300 K, this would be the case for particle sizes larger than about 50...

  20. Friction coefficient determination by electrical resistance measurements

    Science.gov (United States)

    Tunyagi, A.; Kandrai, K.; Fülöp, Z.; Kapusi, Z.; Simon, A.

    2018-05-01

    A simple and low-cost, DIY-type, Arduino-driven experiment is presented for the study of friction and measurement of the friction coefficient, using a conductive rubber cord as a force sensor. It is proposed for high-school or college/university-level students. We strongly believe that it is worthwhile planning, designing and performing Arduino and compatible sensor-based experiments in physics class in order to ensure a better understanding of phenomena, develop theoretical knowledge and multiple experimental skills.

  1. Assessing Reliability of a Multi-Dimensional Scale by Coefficient Alpha

    Directory of Open Access Journals (Sweden)

    Ivan Šerbetar

    2016-04-01

    Full Text Available The purpose of the study was to assess internal consistency by calculating coefficient alpha. It presents the variation in coefficient alpha, depending on questionnaire length and the homogeneity or heterogeneity of the questionnaire. The maximum possible value for coefficient alpha was also calculated by the item elimination method. The study included 99 children aged 10. The children completed The Athletic Coping Skills Inventory – 28 (ACSI-28; Smith et al., 1995, which contains seven constructs: coping with adversity, coachability, concentration, confidence and achievement motivation, goal setting and mental preparation, peaking under pressure and freedom from worry. The results confirmed that the values of the alpha coefficient vary depending on the number and composition of items and the sample size. In terms of item structure, homogeneous constructs yielded lower values for the alpha coefficient (in a range from .48 to .61 than the questionnaire with all the constructs (alpha = .79, despite higher inter-item correlations. In terms of the number of items, the longer test generated higher alpha coefficients (alpha = .79 than the shorter test (half-sets of items = .60, .73, .69, .70. A higher overall value (alpha = .83 can be achieved by item elimination.

  2. Effect of electrostatic field on dynamic friction coefficient of pistachio

    Directory of Open Access Journals (Sweden)

    M. H Aghkhani

    2016-04-01

    25 mm and with wall thickness of 5 mm placed on trolleys. In the bottom of the container a separate aluminum plate was installed as the negative pole of the electric field. The friction plates as a positive pole placed on top of the sample. There were no contact between friction plates and walls of vessel (samples were about 2 to 3 mm higher from the edges of wall. Frictional force changes due to movement of table, measured and recorded by an accurate load cell. From force-displacement curves, the coefficient of dynamic friction and static coefficient of friction calculated. In general, according to the experimental design, 486 tests were performed. Results and Discussion: According to the results of statistical analysis, there is significant interaction affect between pistachios type and electrical field, as well as, the interaction between electrical field and speed, on dynamic coefficient of friction. It means two pistachio types can be separated by electrical charging. Different physical properties of surface of filled non-splits pistachio nuts (such as corners and edges and filled splits ones, caused differences in the distribution of electric charge and as a result, its interaction with the electric field were significant. Changes in dynamic coefficient of friction according to the electric field intensity at different levels of moisture content and speed on the friction surfaces of iron, aluminum and rubber, was drawn in Fig.4, 5 and 6, respectively. These figures reflected the reduction of dynamic coefficient of friction by increasing the movement speed of table. According to Fig.7, increasing the intensity of the electric field increases the dynamic coefficient of friction. Because this leads to build the opposition charge on samples and galvanized iron sheets, and with increase of electrical field, these charges will rise. Fig.9 shows different trends of variation of dynamic coefficient of friction against moisture on rubber surface. This chart shows the

  3. Coefficient adaptive triangulation for strongly anisotropic problems

    Energy Technology Data Exchange (ETDEWEB)

    D`Azevedo, E.F.; Romine, C.H.; Donato, J.M.

    1996-01-01

    Second order elliptic partial differential equations arise in many important applications, including flow through porous media, heat conduction, the distribution of electrical or magnetic potential. The prototype is the Laplace problem, which in discrete form produces a coefficient matrix that is relatively easy to solve in a regular domain. However, the presence of anisotropy produces a matrix whose condition number is increased, making the resulting linear system more difficult to solve. In this work, we take the anisotropy into account in the discretization by mapping each anisotropic region into a ``stretched`` coordinate space in which the anisotropy is removed. The region is then uniformly triangulated, and the resulting triangulation mapped back to the original space. The effect is to generate long slender triangles that are oriented in the direction of ``preferred flow.`` Slender triangles are generally regarded as numerically undesirable since they tend to cause poor conditioning; however, our triangulation has the effect of producing effective isotropy, thus improving the condition number of the resulting coefficient matrix.

  4. The convergence coefficient across political systems.

    Science.gov (United States)

    Gallego, Maria; Schofield, Norman

    2013-01-01

    Formal work on the electoral model often suggests that parties or candidates should locate themselves at the electoral mean. Recent research has found no evidence of such convergence. In order to explain nonconvergence, the stochastic electoral model is extended by including estimates of electoral valence. We introduce the notion of a convergence coefficient, c. It has been shown that high values of c imply that there is a significant centrifugal tendency acting on parties. We used electoral surveys to construct a stochastic valence model of the the elections in various countries. We find that the convergence coefficient varies across elections in a country, across countries with similar regimes, and across political regimes. In some countries, the centripetal tendency leads parties to converge to the electoral mean. In others the centrifugal tendency dominates and some parties locate far from the electoral mean. In particular, for countries with proportional electoral systems, namely, Israel, Turkey, and Poland, the centrifugal tendency is very high. In the majoritarian polities of the United States and Great Britain, the centrifugal tendency is very low. In anocracies, the autocrat imposes limitations on how far from the origin the opposition parties can move.

  5. Sets of Fourier coefficients using numerical quadrature

    International Nuclear Information System (INIS)

    Lyness, J. N.

    2001-01-01

    One approach to the calculation of Fourier trigonometric coefficients f(r) of a given function f(x) is to apply the trapezoidal quadrature rule to the integral representation f(r)=(line i ntegral)(sub 0)(sup 1) f(x)e(sup -2(pi)irx)dx. Some of the difficulties in this approach are discussed. A possible way of overcoming many of these is by means of a subtraction function. Thus, one sets f(x)= h(sub p-1)(x)+ g(sub p)(x), where h(sub -1)(x) is an algebraic polynomial of degree p-1, specified in such a way that the Fourier series of g(sub p)(x) converges more rapidly than that of f(x). To obtain the Fourier coefficients of f(x), one uses an analytic expression for those of h(sub p-1)(x) and numerical quadrature to approximately those of g(sub p)(x)

  6. Full wave-field reflection coefficient inversion.

    Science.gov (United States)

    Dettmer, Jan; Dosso, Stan E; Holland, Charles W

    2007-12-01

    This paper develops a Bayesian inversion for recovering multilayer geoacoustic (velocity, density, attenuation) profiles from a full wave-field (spherical-wave) seabed reflection response. The reflection data originate from acoustic time series windowed for a single bottom interaction, which are processed to yield reflection coefficient data as a function of frequency and angle. Replica data for inversion are computed using a wave number-integration model to calculate the full complex acoustic pressure field, which is processed to produce a commensurate seabed response function. To address the high computational cost of calculating short range acoustic fields, the inversion algorithms are parallelized and frequency averaging is replaced by range averaging in the forward model. The posterior probability density is interpreted in terms of optimal parameter estimates, marginal distributions, and credibility intervals. Inversion results for the full wave-field seabed response are compared to those obtained using plane-wave reflection coefficients. A realistic synthetic study indicates that the plane-wave assumption can fail, producing erroneous results with misleading uncertainty bounds, whereas excellent results are obtained with the full-wave reflection inversion.

  7. The Convergence Coefficient across Political Systems

    Science.gov (United States)

    Schofield, Norman

    2013-01-01

    Formal work on the electoral model often suggests that parties or candidates should locate themselves at the electoral mean. Recent research has found no evidence of such convergence. In order to explain nonconvergence, the stochastic electoral model is extended by including estimates of electoral valence. We introduce the notion of a convergence coefficient, c. It has been shown that high values of c imply that there is a significant centrifugal tendency acting on parties. We used electoral surveys to construct a stochastic valence model of the the elections in various countries. We find that the convergence coefficient varies across elections in a country, across countries with similar regimes, and across political regimes. In some countries, the centripetal tendency leads parties to converge to the electoral mean. In others the centrifugal tendency dominates and some parties locate far from the electoral mean. In particular, for countries with proportional electoral systems, namely, Israel, Turkey, and Poland, the centrifugal tendency is very high. In the majoritarian polities of the United States and Great Britain, the centrifugal tendency is very low. In anocracies, the autocrat imposes limitations on how far from the origin the opposition parties can move. PMID:24385886

  8. Thermal neutron diffusion cooling coefficient for plexiglass

    International Nuclear Information System (INIS)

    Drozdowicz, K.

    1992-08-01

    The thermal neutron diffusion cooling coefficient is a macroscopic material parameter. It is needed for description of the decay of the thermal neutron pulse in a medium and gives information of the diffusion cooling of the thermal neutron spectrum in a bounded volume. Experimental results from various measurements for plexiglass are overviewed in the paper. A method for theoretical, exact calculation of the parameter is presented. The formula utilizes some other thermal neutron parameters and a cooling function, i.e. the function which describes the deviation of the neutron spectrum in a bounded system from the distribution in an infinite one. The energy dependence of the function is obtained numerically from relations which results from the eigenvalue problem of the scattering operator when both the decay constant and the spectrum of the thermal neutron flux are developed on powers of the geometrical buckling. The case of a 1/ν absorption cross section is considered. The calculation utilizes a synthetic scattering function elaborated for hydrogenous media by GRANADA (1985). The influence of some quantities used in the calculation on the final result is investigated. The obtained value of the diffusion cooling coefficient for plexiglass is C = 6514 cm 4 s -1 at the temperature of 20 degrees C. The uncertainty is estimated to be ± 100 cm 4 s -1 within the physical model of the scattering kernel used. (au)

  9. [Determination of a Friction Coefficient for THA Bearing Couples].

    Science.gov (United States)

    Vrbka, M; Nečas, D; Bartošík, J; Hartl, M; Křupka, I; Galandáková, A; Gallo, J

    2015-01-01

    The wear of articular surfaces is considered one of the most important factors limiting the life of total hip arthroplasty (THA). It is assumed that the particles released from the surface of a softer material induce a complex inflammatory response, which will eventually result in osteolysis and aseptic loosening. Implant wear is related to a friction coefficient which depends on combination of the materials used, roughness of the articulating surfaces, internal clearance, and dimensions of the prosthesis. The selected parameters of the bearing couples tested were studied using an experimental device based on the principle of a pendulum. Bovine serum was used as a lubricant and the load corresponded to a human body mass of 75 kg. The friction coefficient was derived from a curve of slowdown of pendulum oscillations. Roughness was measured with a device working on the principle of interferometry. Clearance was assessed by measuring diameters of the acetabular and femoral heads with a 3D optical scanner. The specimens tested included unused metal-on-highly cross-linked polyethylene, ceramic-on-highly cross-linked polyethylene and ceramic-on-ceramic bearing couples with the diameters of 28 mm and 36 mm. For each measured parameter, an arithmetic mean was calculated from 10 measurements. 1) The roughness of polyethylene surfaces was higher by about one order of magnitude than the roughness of metal and ceramic components. The Protasul metal head had the least rough surface (0.003 μm). 2) The ceramic-on-ceramic couples had the lowest clearance. Bearing couples with polyethylene acetabular liners had markedly higher clearances ranging from 150 μm to 545 μm. A clearance increased with large femoral heads (up to 4-fold in one of the couple tested). 3) The friction coefficient was related to the combination of materials; it was lowest in ceramic-on-ceramic surfaces (0.11 to 0.12) and then in ceramic-on-polyethylene implants (0.13 to 0.14). The friction coefficient is

  10. Questionnaire discrimination: (re-introducing coefficient δ

    Directory of Open Access Journals (Sweden)

    Hankins Matthew

    2007-05-01

    Full Text Available Abstract Background Questionnaires are used routinely in clinical research to measure health status and quality of life. Questionnaire measurements are traditionally formally assessed by indices of reliability (the degree of measurement error and validity (the extent to which the questionnaire measures what it is supposed to measure. Neither of these indices assesses the degree to which the questionnaire is able to discriminate between individuals, an important aspect of measurement. This paper introduces and extends an existing index of a questionnaire's ability to distinguish between individuals, that is, the questionnaire's discrimination. Methods Ferguson (1949 1 derived an index of test discrimination, coefficient δ, for psychometric tests with dichotomous (correct/incorrect items. In this paper a general form of the formula, δG, is derived for the more general class of questionnaires allowing for several response choices. The calculation and characteristics of δG are then demonstrated using questionnaire data (GHQ-12 from 2003–2004 British Household Panel Survey (N = 14761. Coefficients for reliability (α and discrimination (δG are computed for two commonly-used GHQ-12 coding methods: dichotomous coding and four-point Likert-type coding. Results Both scoring methods were reliable (α > 0.88. However, δG was substantially lower (0.73 for the dichotomous coding of the GHQ-12 than for the Likert-type method (δG = 0.96, indicating that the dichotomous coding, although reliable, failed to discriminate between individuals. Conclusion Coefficient δG was shown to have decisive utility in distinguishing between the cross-sectional discrimination of two equally reliable scoring methods. Ferguson's δ has been neglected in discussions of questionnaire design and performance, perhaps because it has not been implemented in software and was restricted to questionnaires with dichotomous items, which are rare in health care research. It is

  11. Deformation of SS 304 LN during Scratch Test and Influence on Evolution of Coefficient of Friction

    Directory of Open Access Journals (Sweden)

    Satender Kataria

    2009-01-01

    Full Text Available An AISI 304 LN nuclear grade forged, metallographically polished specimen was subjected to progressive load scratch tests using a spheroconical indenter at three different scratch speeds 1, 3, and 27 mm/min. The present study attempts to address the evolution of coefficient of friction with scratch speed invoking its correlation with scratch induced deformation in the specimen. At higher scratch speeds, plastic deformation rates were higher which caused friction coefficient to be of higher magnitude. This was correlated with dynamically obtained high resolution optical images that revealed deformation driven microstructural alterations. These alterations significantly influenced the evolution of friction coefficient which was intimately related to plasticity of the surface.

  12. APRECOT - analysis program for reactivity coefficient tests

    International Nuclear Information System (INIS)

    Telford, A.R.R.

    1979-05-01

    A computer program has been written which provides a rapid and convenient analysis route for fuel temperature coefficient of reactivity measurements, as carried out at Hinkley Point 'B' Power Station. This replaces the earlier, more tedious, iterative analysis using KINAGRAX. The program has been tested by analysing computer simulations of reactor tests. This has shown that APRECOT introduces errors which are small (approximately 11/2%) in comparison with other sources of error (approximately 10%), that the effect of axial flux shape changes is acceptably small and that effects due to xenon, which is not modelled in the current version of the program, can be dealt with adequately. This note describes the APRECOT method, including details of input and output to the program and gives results of the numerical tests made of the method. (author)

  13. Stochastic algorithm for simulating gas transport coefficients

    Science.gov (United States)

    Rudyak, V. Ya.; Lezhnev, E. V.

    2018-02-01

    The aim of this paper is to create a molecular algorithm for modeling the transport processes in gases that will be more efficient than molecular dynamics method. To this end, the dynamics of molecules are modeled stochastically. In a rarefied gas, it is sufficient to consider the evolution of molecules only in the velocity space, whereas for a dense gas it is necessary to model the dynamics of molecules also in the physical space. Adequate integral characteristics of the studied system are obtained by averaging over a sufficiently large number of independent phase trajectories. The efficiency of the proposed algorithm was demonstrated by modeling the coefficients of self-diffusion and the viscosity of several gases. It was shown that the accuracy comparable to the experimental one can be obtained on a relatively small number of molecules. The modeling accuracy increases with the growth of used number of molecules and phase trajectories.

  14. Clustering stocks using partial correlation coefficients

    Science.gov (United States)

    Jung, Sean S.; Chang, Woojin

    2016-11-01

    A partial correlation analysis is performed on the Korean stock market (KOSPI). The difference between Pearson correlation and the partial correlation is analyzed and it is found that when conditioned on the market return, Pearson correlation coefficients are generally greater than those of the partial correlation, which implies that the market return tends to drive up the correlation between stock returns. A clustering analysis is then performed to study the market structure given by the partial correlation analysis and the members of the clusters are compared with the Global Industry Classification Standard (GICS). The initial hypothesis is that the firms in the same GICS sector are clustered together since they are in a similar business and environment. However, the result is inconsistent with the hypothesis and most clusters are a mix of multiple sectors suggesting that the traditional approach of using sectors to determine the proximity between stocks may not be sufficient enough to diversify a portfolio.

  15. Tracking time-varying coefficient-functions

    DEFF Research Database (Denmark)

    Nielsen, Henrik Aalborg; Nielsen, Torben Skov; Joensen, Alfred K.

    2000-01-01

    A method for adaptive and recursive estimation in a class of non-linear autoregressive models with external input is proposed. The model class considered is conditionally parametric ARX-models (CPARX-models), which is conventional ARX-models in which the parameters are replaced by smooth, but oth......A method for adaptive and recursive estimation in a class of non-linear autoregressive models with external input is proposed. The model class considered is conditionally parametric ARX-models (CPARX-models), which is conventional ARX-models in which the parameters are replaced by smooth...... is a combination of recursive least squares with exponential forgetting and local polynomial regression. It is argued, that it is appropriate to let the forgetting factor vary with the value of the external signal which is the argument of the coefficient functions. Some of the key properties of the modified method...

  16. Molar extinction coefficients of some fatty acids

    DEFF Research Database (Denmark)

    Sandhu, G.K.; Singh, K.; Lark, B.S.

    2002-01-01

    The attenuation of gamma rays in some fatty acids, viz. formic acid (CH2O2), acetic acid (C2H4O2), propionic acid (C3H6O2), butyric acid (C4H8O2), n-hexanoic acid (C6H12O2), n-caprylic acid (C8H16O2), lauric acid (C12H24O2), myristic acid (C14H28O2), palmitic acid (C16H32O2), oleic acid (C18H34O2......) and stearic acid (C18H36O2), has been measured at the photon energies 81, 356, 511, 662, 1173 and 1332 keV. Experimental values for the molar extinction coefficient, the effective atomic number and the electron density have been derived and compared with theoretical calculations. There is good agreement...

  17. Coefficient of performance of Stirling refrigerators

    Science.gov (United States)

    E Mungan, Carl

    2017-09-01

    Stirling coolers transfer heat in or out of the working fluid during all four stages of their operation, and their coefficient of performance depends on whether the non-isothermal heat exchanges are performed reversibly or irreversibly. Both of these possibilities can in principle be arranged. Notably, if the working fluid is an ideal gas, the input of energy in the form of heat during one isochoric step is equal in magnitude to the output during the other isochoric step in the cycle. The theoretical performance of the fridge can then attain the reversible Carnot limit if a regenerator is used, which is a high heat capacity material through which the gas flows. Various Stirling refrigerator configurations are analysed in this article at a level of presentation suitable for an introductory undergraduate thermodynamics course.

  18. Thermal expansion coefficient determination by CBED

    International Nuclear Information System (INIS)

    Angelini, P.; Bentley, J.

    1984-01-01

    The present application of CBED involves measurements of thermal-expansion coefficients by measurement of changes in HOLZ line positions as a function of temperature. Previous work on this subject was performed on Si at a constant accelerating voltage of 100 kV between about 90 and 600 K. Diffraction patterns were recorded and line shifts correlated to lattice parameter changes. Differences were noted between values determined by CBED and accepted thermal expansion values. Significant HOLZ line interactions and splitting occurring in the (111) patterns were noted to contribute to the differences. Preliminary measurements have been made on Al, Al 2 O 3 , and single-crystal tau (Ni/sub 20.3/Ti/sub 2.7/B 6 ). An example of changes in HOLZ lines present in (114) patterns for Al are shown and the effect of temperature on the position of lines in the pattern illustrated

  19. Upper bounds for flexoelectric coefficients in ferroelectrics

    Science.gov (United States)

    Yudin, P. V.; Ahluwalia, R.; Tagantsev, A. K.

    2014-02-01

    Flexoelectric effect is the response of electric polarization to the mechanical strain gradient. At the nano-scale, where large strain gradients are expected, the flexoelectric effect becomes appreciable and may substitute piezoelectric effect in centrosymmetric materials. These features make flexoelectricity of growing interest during the last decade. At the same time, the available theoretical and experimental results are rather contradictory. In particular, experimentally measured flexoelectric coefficients in some ferroelectric materials largely exceed theoretically predicted values. Here, we determine the upper limits for the magnitude of the static bulk contribution to the flexoelectric effect in ferroelectrics, the contribution which was customarily considered as the dominating one. The magnitude of the upper bounds obtained suggests that the anomalously high flexoelectric coupling documented for perovskite ceramics can hardly be attributed to a manifestation of the static bulk effect.

  20. Thermal linear expansion coefficient of structural graphites

    International Nuclear Information System (INIS)

    Virgil'ev, Yu.S.

    1995-01-01

    The data now available on radiation induced changes of linear thermal expansion coefficients (CTE) for native structural carbon materials (SCM) irradiated with high fluences are summarized. For different types of native and foreign SCM dose dependences of CTE changes in the temperature range of 300...1600 K and at fluences up to (2...3)x10 22 n/cm 2 (E>0.18 meV) are compared. On the base of this comparison factors defined the CTE changes under neutron irradiation are revealed and the explanation of observed phenomena is offered. Large number of the factors revealed does not allowed to calculate CTE radiation induced changes. 39 refs.; 16 figs.; 5 tabs

  1. Effective Electrocardiogram Steganography Based on Coefficient Alignment.

    Science.gov (United States)

    Yang, Ching-Yu; Wang, Wen-Fong

    2016-03-01

    This study presents two types of data hiding methods based on coefficient alignment for electrocardiogram (ECG) signals, namely, lossy and reversible ECG steganographys. The lossy method is divided into high-quality and high-capacity ECG steganography, both of which are capable of hiding confidential patient data in ECG signals. The reversible data hiding method can not only hide secret messages but also completely restore the original ECG signal after bit extraction. Simulations confirmed that the perceived quality generated by the lossy ECG steganography methods was good, while hiding capacity was acceptable. In addition, these methods have a certain degree of robustness, which is rare in conventional ECG stegangraphy schemes. Moreover, the proposed reversible ECG steganography method can not only successfully extract hidden messages but also completely recover the original ECG data.

  2. Friction Experiments for Dynamical Coefficient Measurement

    Directory of Open Access Journals (Sweden)

    J. J. Arnoux

    2011-01-01

    Full Text Available An experimental study, including three experimental devices, is presented in order to investigate dry friction phenomena in a wide range of sliding speeds for the steel on steel contact. A ballistic setup, with an air gun launch, allows to estimate the friction coefficient between 20 m/s and 80 m/s. Tests are completed by an adaptation of the sensor on a hydraulic tensile machine (0.01 m/s to 3 m/s and a pin-on-disk tribometer mounted on a CNC lathe (1 to 30 m/s. The interactions at the asperity scale are characterized by a white light interferometer surface analysis.

  3. Tensor models, Kronecker coefficients and permutation centralizer algebras

    Science.gov (United States)

    Geloun, Joseph Ben; Ramgoolam, Sanjaye

    2017-11-01

    We show that the counting of observables and correlators for a 3-index tensor model are organized by the structure of a family of permutation centralizer algebras. These algebras are shown to be semi-simple and their Wedderburn-Artin decompositions into matrix blocks are given in terms of Clebsch-Gordan coefficients of symmetric groups. The matrix basis for the algebras also gives an orthogonal basis for the tensor observables which diagonalizes the Gaussian two-point functions. The centres of the algebras are associated with correlators which are expressible in terms of Kronecker coefficients (Clebsch-Gordan multiplicities of symmetric groups). The color-exchange symmetry present in the Gaussian model, as well as a large class of interacting models, is used to refine the description of the permutation centralizer algebras. This discussion is extended to a general number of colors d: it is used to prove the integrality of an infinite family of number sequences related to color-symmetrizations of colored graphs, and expressible in terms of symmetric group representation theory data. Generalizing a connection between matrix models and Belyi maps, correlators in Gaussian tensor models are interpreted in terms of covers of singular 2-complexes. There is an intriguing difference, between matrix and higher rank tensor models, in the computational complexity of superficially comparable correlators of observables parametrized by Young diagrams.

  4. Auger coefficient in GaInN-based laser structures

    Energy Technology Data Exchange (ETDEWEB)

    Draeger, Alexander Daniel; Netzel, Carsten; Brendel, Moritz; Joenen, Holger; Rossow, Uwe; Hangleiter, Andreas [Institut fuer Angewandte Physik, TU Braunschweig (Germany)

    2010-07-01

    Todays GaInN-based light emitting devices such as LEDs and laser diodes show excellent properties in terms of quantum efficiency or threshold current in the violet-blue spectral region. With increasing wavelength towards the green this performance decreases strongly. In particular at longer wavelengths, the quantum efficiency decreases for higher current densities, called the efficiency droop. This phenomenon is still subject to intensive research and different mechanisms such as Auger recombination, losses due to dislocations and carrier escape have been named as possible explanations. We combine optical gain measurements using the variable stripe length technique with model calculations of the optical gain spectra to derive the carrier lifetime. From the dependence of the inverse effective lifetime on carrier density we determine the recombination coefficients for radiative, nonradiative and Auger recombination. The Auger coefficients we obtained are about 1-2 x 10{sup -31} cm{sup 6}/s for GaInN quantum wells with 2.5eV

  5. Friction coefficient and effective interference at the implant-bone interface.

    Science.gov (United States)

    Damm, Niklas B; Morlock, Michael M; Bishop, Nicholas E

    2015-09-18

    Although the contact pressure increases during implantation of a wedge-shaped implant, friction coefficients tend to be measured under constant contact pressure, as endorsed in standard procedures. Abrasion and plastic deformation of the bone during implantation are rarely reported, although they define the effective interference, by reducing the nominal interference between implant and bone cavity. In this study radial forces were analysed during simulated implantation and explantation of angled porous and polished implant surfaces against trabecular bone specimens, to determine the corresponding friction coefficients. Permanent deformation was also analysed to determine the effective interference after implantation. For the most porous surface tested, the friction coefficient initially increased with increasing normal contact stress during implantation and then decreased at higher contact stresses. For a less porous surface, the friction coefficient increased continually with normal contact stress during implantation but did not reach the peak magnitude measured for the rougher surface. Friction coefficients for the polished surface were independent of normal contact stress and much lower than for the porous surfaces. Friction coefficients were slightly lower for pull-out than for push-in for the porous surfaces but not for the polished surface. The effective interference was as little as 30% of the nominal interference for the porous surfaces. The determined variation in friction coefficient with radial contact force, as well as the loss of interference during implantation will enable a more accurate representation of implant press-fitting for simulations. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. The heat transfer coefficients of the heating surface of 300 MWe CFB boiler

    Science.gov (United States)

    Wu, Haibo; Zhang, Man; Lu, Qinggang; Sun, Yunkai

    2012-08-01

    A study of the heat transfer about the heating surface of three commercial 300 MWe CFB boilers was conducted in this work. The heat transfer coefficients of the platen heating surface, the external heat exchanger (EHE) and cyclone separator were calculated according to the relative operation data at different boiler loads. Moreover, the heat transfer coefficient of the waterwall was calculated by heat balance of the hot circuit of the CFB boiler. With the boiler capacity increasing, the heat transfer coefficients of these heating surface increases, and the heat transfer coefficient of the water wall is higher than that of the platen heating surface. The heat transfer coefficient of the EHE is the highest in high boiler load, the heat transfer coefficient of the cyclone separator is the lowest. Because the fired coal is different from the design coal in No.1 boiler, the ash content of the fired coal is much lower than that of the design coal. The heat transfer coefficients which calculated with the operation data are lower than the previous design value and that is the reason why the bed temperature is rather high during the boiler operation in No.1 boiler.

  7. Predicted sound absorption coefficients of absorber materials lined in a chamber

    Directory of Open Access Journals (Sweden)

    Farhad Forouharmajd

    2014-01-01

    Full Text Available Aims: The present study was aimed to measurement of sound absorption coefficient of mineral wool and determination of their absorption ability. Materials and Methods: Mineral wool was used to find noise absorption coefficient. Random and normal sound absorption coefficient values were predicted. Then, the measures of transmission loss calculated as an overall value, for applied absorbent material and bare sheet metal. Results: The measured values of noise with one octave band frequency demonstrated an attenuation of 5.5-7 dB for these frequencies. The absorption coefficients of materials showed that mineral wool had more normal sound coefficients than its random sound absorption coefficient values. Conclusion: It can be concluded that predicted normal sound absorption coefficients of used mineral wool materials were near to the areas of standard line. It seems that the amount or thickness of absorbent lining was a main reason of noise reduction in low band frequencies. Mineral wool has a higher density and can provide better acoustical and insulating results than fiberglass. Besides, mineral wool doesn′t lose its insulating value when wet and has an outstanding resistance to fire.

  8. Partition coefficients of organic compounds in lipid-water systems and correlations with fish bioconcentration factors

    Science.gov (United States)

    Chiou, C.T.

    1985-01-01

    Triolein-water partition coefficients (KtW) have been determined for 38 slightly water-soluble organic compounds, and their magnitudes have been compared with the corresponding octanol-water partition coefficients (KOW). In the absence of major solvent-solute interaction effects in the organic solvent phase, the conventional treatment (based on Raoult's law) predicts sharply lower partition coefficients for most of the solutes in triolein because of its considerably higher molecular weight, whereas the Flory-Huggins treatment predicts higher partition coefficients with triolein. The data are in much better agreement with the Flory-Huggins model. As expected from the similarity in the partition coefficients, the water solubility (which was previously found to be the major determinant of the KOW) is also the major determinant for the Ktw. When the published BCF values (bioconcentration factors) of organic compounds in fish are based on the lipid content rather than on total mass, they are approximately equal to the Ktw, which suggests at least near equilibrium for solute partitioning between water and fish lipid. The close correlation between Ktw and Kow suggests that Kow is also a good predictor for lipid-water partition coefficients and bioconcentration factors.

  9. Attenuation coefficient determination of printed ABS and PLA samples in diagnostic radiology standard beams

    International Nuclear Information System (INIS)

    Veneziani, G.R.; Correa, E.L.; Potiens, M.P.A.; Campos, L.L.

    2015-01-01

    IAEA code of practice TRS-457 states that standard phantoms should offer the same primary attenuation and scatter production as relevant body section of a representative patient. Material cost, availability and dimensional stability must also be considered. The goal of this study is to determine the attenuation coefficient of printed ABS and PLA in standard X-ray beams, verifying if phantoms printed with these materials could be an easier-handle substitute for PMMA, enabling the creation of different designs in an easier and cheaper way. Results show that PMMA presents higher attenuation coefficient, followed by PLA and ABS, which means that thinner PMMA layer creates higher radiation attenuation. (author)

  10. Computing exact Fourier series coefficients of IC rectilinear polygons from low-resolution fast Fourier coefficients

    Science.gov (United States)

    Scheibler, Robin; Hurley, Paul

    2012-03-01

    We present a novel, accurate and fast algorithm to obtain Fourier series coefficients from an IC layer whose description consists of rectilinear polygons on a plane, and how to implement it using off-the-shelf hardware components. Based on properties of Fourier calculus, we derive a relationship between the Discrete Fourier Transforms of the sampled mask transmission function and its continuous Fourier series coefficients. The relationship leads to a straightforward algorithm for computing the continuous Fourier series coefficients where one samples the mask transmission function, compute its discrete Fourier transform and applies a frequency-dependent multiplicative factor. The algorithm is guaranteed to yield the exact continuous Fourier series coefficients for any sampling representing the mask function exactly. Computationally, this leads to significant saving by allowing to choose the maximal such pixel size and reducing the fast Fourier transform size by as much, without compromising accuracy. In addition, the continuous Fourier series is free from aliasing and follows closely the physical model of Fourier optics. We show that in some cases this can make a significant difference, especially in modern very low pitch technology nodes.

  11. Temperature coefficient for modeling denitrification in surface water sediments using the mass transfer coefficient

    Science.gov (United States)

    T.W. Appelboom; G.M. Chescheir; F. Birgand; R.W. Skaggs; J.W. Gilliam; D. Amatya

    2010-01-01

    Watershed modeling has become an important tool for researchers. Modeling nitrate transport within drainage networks requires quantifying the denitrification within the sediments in canals and streams. In a previous study, several of the authors developed an equation using a term called a mass transfer coefficient to mathematically describe sediment denitrification....

  12. Temperature Coefficient for Modeling Denitrification in Surface Water Sediments Using the Mass Transfer Coefficient

    Science.gov (United States)

    T. W. Appelboom; G. M. Chescheir; R. W. Skaggs; J. W. Gilliam; Devendra M. Amatya

    2006-01-01

    Watershed modeling has become an important tool for researchers with the high costs of water quality monitoring. When modeling nitrate transport within drainage networks, denitrification within the sediments needs to be accounted for. Birgand et. al. developed an equation using a term called a mass transfer coefficient to mathematically describe sediment...

  13. Dielectronic recombination rate coefficients to the excited states of CII from CIII

    International Nuclear Information System (INIS)

    Kato, Takako; Safronova, U.; Ohira, Mituhiko.

    1996-02-01

    Energy levels, radiative transition probabilities and autoionization rates for CII including 1s 2 2l2l'nl'' (n=2-6, l'≤(n-1)) states were calculated by using multi-configurational Hartree-Fock (Cowan code) method. Autoionizing levels above three thresholds: 1s 2 2s 2 ( 1 S), 1s 2 2s2p( 3 P), 1s 2 2s2p( 1 P) were considered. Branching ratios related to the first threshold and the intensity factor were calculated for satellite lines of CII ion. The dielectronic recombination rate coefficients to the excited states for n=2-6 are calculated with these atomic data. The rate coefficients are fitted to an analytical formula and the fit parameters are given. The values for higher excited states than n=6 are extrapolated and the total dielectronic recombination rate coefficients are derived. The effective recombination rate coefficient for different electron densities are also derived. (author)

  14. Analysis of temperature reactivity coefficient at very high burn-ups for pressurized water reactor

    International Nuclear Information System (INIS)

    Yu Shihe; Dai Xiang; Cao Xinrong

    2012-01-01

    In the high burn-up core, as the initial enrichment increases, the fast/thermal flux ratio also increases. The harder neutron spectrum influences the temperature reactivity coefficients. In this paper, a very high burn-up core was designed, very high burn-up levels was achieved using higher enrichments and various feed assembly and loading pattern options. The CASMO-4/SIMULATE-3 code system is used to model the high burn-up core and calculate temperature reactivity coefficient for the burn-up more than 60 GWD/T. The results show that the hardening of the neutron spectrum leads to more negative moderator temperature coefficients at high burn-ups irrespective of whether or not there is burnable poison; the is little variation with fuel temperature coefficient. (authors)

  15. Drag coefficients of lattice masts from full-scale wind-tunnel tests

    DEFF Research Database (Denmark)

    Georgakis, Christos; Støttrup-Andersen, Ulrik; Johnsen, Marie

    2009-01-01

    In this paper, the drag coefficients obtained from a series of full-scale section model wind-tunnel tests of several lattice mast configurations are presented and compared to those provided in Eurocode 3 and ESDU. The drag coefficients provided in Eurocode are conservative interpretations of 1......:5 scale section model tests performed at the National Physics Laboratory and the National Maritime Institute in the UK in the 1970´s. ESDU provides velocity-dependent drag coefficients equivalent to those obtained from the same series of tests. In all cases, the mast legs and diagonals are comprised...... primarily of circular hollow sections, putting into question the validity of the scaled tests from the 70’s. The results of the full-scale tests show that the drag coefficients of the masts have lower values than those obtained from the scaled tests for turbulent wind and higher for winds with low...

  16. Hodge-DeRham theory with degenerating coefficients

    International Nuclear Information System (INIS)

    Fouad, E.

    2006-12-01

    Let L be a variation of Hod ge structures on the complement X* of a normal crossing divisor (NCD) Y in a smooth analytic variety X and let j : X* = X - Y → X denote the open embedding. The purpose of this paper is to describe the weight filtration W on a combinatorial logarithmic complex computing the (higher) direct image j * L, underlying a mixed Hodge complex when X is proper, proving in this way the results in the note [14] generalizing the constant coefficients case. When a morphism f : X → D to a complex disc is given with Y = f -1 (0), the weight filtration on the complex of nearby cocycles Ψ f (L) on Y can be described by these logarithmic techniques and a comparison theorem shows that the filtration coincides with the weight defined by the logarithm of the monodromy which provides the link with various results on the subject. (author)

  17. Apparent diffusion coefficient measurements in progressive supranuclear palsy

    Energy Technology Data Exchange (ETDEWEB)

    Ohshita, T.; Oka, M.; Imon, Y.; Yamaguchi, S.; Mimori, Y.; Nakamura, S. [Hiroshima Univ. (Japan). School of Medicine

    2000-09-01

    We measured the apparent diffusion coefficient (ADC), using diffusion-weighted imaging (DWI) and signal intensity on T2-weighted MRI in the cerebral white matter of patients with progressive supranuclear palsy (PSP) and age-matched normal subjects. In PSP, ADC in the prefrontal and precentral white matter was significantly higher than in controls. There was no significant difference in signal intensity on T2-weighted images. The ADC did correlate with signal intensity. The distribution of the elevation of ADC may be the consequence of underlying pathological changes, such as neurofibrillary tangles or glial fibrillary tangles in the cortex. Our findings suggest that ADC measurement might be useful for demonstrating subtle neuropathological changes. (orig.)

  18. Reassessment of tritium dose coefficients for the general public

    International Nuclear Information System (INIS)

    Melintescu, A.; Galeriu, D.; Takeda, H.

    2007-01-01

    Concerns of increased risk from tritium intake by humans have been claimed in the past. The arguments concerning the radiobiological effectiveness of tritium, its longer retention in the human body and the presence of tritium in the DNA hydration shell are analysed in this paper. A biokinetic model for tritiated water and organically bound tritium retention in the human body is used, based on a common approach for mammals using energy and hydrogen metabolism and tested separately with animal experiments. Extension to this model to humans considers the increased role of the brain, food quality and unique growth patterns of humans. Various ages and genders for Caucasians are considered. For an intake of tritium in organic forms in the diet, the retention for the female is of about a factor 2 compared with ICRP recommendations. Effective dose coefficients are estimated to be about a factor of 2 to 3 higher than those of the ICRP. (authors)

  19. Efeito da endogamia sobre a maturidade sexual e fecundidade do escargot da espécie Helix aspersa Effect of inbreeding on sexual maturity and fertility of edible snail Helix aspersa

    Directory of Open Access Journals (Sweden)

    E.D.R. Soares

    2003-10-01

    Full Text Available Estudou-se o efeito da endogamia sobre a maturidade sexual e fecundidade de escargot da espécie Helix aspersa, em três gerações consecutivas de irmãos perfeitos. Os animais foram criados em laboratório com temperatura entre 20 e 25ºC e umidade relativa entre 70 e 90%. O efeito da endogamia foi negativo para as duas características. Quando o valor de F aumentou de 0,25 para 0,50, o percentual de animais sexualmente maduros aos 120 dias diminuiu de 59 para 18% e o número de animais nascidos por postura diminuiu de 94 para 53. Para evitar o efeito negativo, recomenda-se o início de uma criação com pelo menos 100 reprodutores não aparentados, introduzindo-se novas matrizes após a 10ª geração.The effect of inbreeding on two reproductive traits (number of birth per clutch and percentage of sexually mature animals per clutch on three consecutive generations of full sibs of edible snail raised under laboratory conditions (20-25ºC temperature; 70-90% relative humidity was studied. Inbreeding effect was negative for both traits. When F values increased from 0.25 to 0.50, percentages of sexually mature animals after 120 days from birth, decreased from 59 to 18% and the number of birth per clutch decreased from 94 to 53. Population size of at least 100 non related mating snail replaced after 10 generations to avoid inbreeding effect is recommended.

  20. Organ dose conversion coefficients for pediatric reference computational phantoms in external photon radiation fields

    Science.gov (United States)

    Chang, Lienard A.

    In the event of a radiological accident or attack, it is important to estimate the organ doses to those exposed. In general, it is difficult to measure organ dose directly in the field and therefore dose conversion coefficients (DCC) are needed to convert measurable values such as air kerma to organ dose. Previous work on these coefficients has been conducted mainly for adults with a focus on radiation protection workers. Hence, there is a large gap in the literature for pediatric values. This study coupled a Monte Carlo N-Particle eXtended (MCNPX) code with International Council of Radiological Protection (ICRP)-adopted University of Florida and National Cancer Institute pediatric reference phantoms to calculate a comprehensive list of dose conversion coefficients (mGy/mGy) to convert air-kerma to organ dose. Parameters included ten phantoms (newborn, 1-year, 5-year, 10-year, 15-year old male and female), 28 organs over 33 energies between 0.01 and 20 MeV in six (6) irradiation geometries relevant to a child who might be exposed to a radiological release: anterior-posterior (AP), posterior-anterior (PA), right-lateral (RLAT), left-lateral (LLAT), rotational (ROT), and isotropic (ISO). Dose conversion coefficients to the red bone marrow over 36 skeletal sites were also calculated. It was hypothesized that the pediatric organ dose conversion coefficients would follow similar trends to the published adult values as dictated by human anatomy, but be of a higher magnitude. It was found that while the pediatric coefficients did yield similar patterns to that of the adult coefficients, depending on the organ and irradiation geometry, the pediatric values could be lower or higher than that of the adult coefficients.

  1. Organ and effective dose rate coefficients for submersion exposure in occupational settings

    Energy Technology Data Exchange (ETDEWEB)

    Veinot, K.G. [Easterly Scientific, Knoxville, TN (United States); Y-12 National Security Complex, Oak Ridge, TN (United States); Dewji, S.A.; Hiller, M.M. [Center for Radiation Protection Knowledge, Oak Ridge National Laboratory, Oak Ridge, TN (United States); Eckerman, K.F.; Easterly, C.E. [Easterly Scientific, Knoxville, TN (United States)

    2017-11-15

    External dose coefficients for environmental exposure scenarios are often computed using assumption on infinite or semi-infinite radiation sources. For example, in the case of a person standing on contaminated ground, the source is assumed to be distributed at a given depth (or between various depths) and extending outwards to an essentially infinite distance. In the case of exposure to contaminated air, the person is modeled as standing within a cloud of infinite, or semi-infinite, source distribution. However, these scenarios do not mimic common workplace environments where scatter off walls and ceilings may significantly alter the energy spectrum and dose coefficients. In this paper, dose rate coefficients were calculated using the International Commission on Radiological Protection (ICRP) reference voxel phantoms positioned in rooms of three sizes representing an office, laboratory, and warehouse. For each room size calculations using the reference phantoms were performed for photons, electrons, and positrons as the source particles to derive mono-energetic dose rate coefficients. Since the voxel phantoms lack the resolution to perform dose calculations at the sensitive depth for the skin, a mathematical phantom was developed and calculations were performed in each room size with the three source particle types. Coefficients for the noble gas radionuclides of ICRP Publication 107 (e.g., Ne, Ar, Kr, Xe, and Rn) were generated by folding the corresponding photon, electron, and positron emissions over the mono-energetic dose rate coefficients. Results indicate that the smaller room sizes have a significant impact on the dose rate per unit air concentration compared to the semi-infinite cloud case. For example, for Kr-85 the warehouse dose rate coefficient is 7% higher than the office dose rate coefficient while it is 71% higher for Xe-133. (orig.)

  2. Organ and effective dose rate coefficients for submersion exposure in occupational settings

    International Nuclear Information System (INIS)

    Veinot, K.G.; Dewji, S.A.; Hiller, M.M.; Eckerman, K.F.; Easterly, C.E.

    2017-01-01

    External dose coefficients for environmental exposure scenarios are often computed using assumption on infinite or semi-infinite radiation sources. For example, in the case of a person standing on contaminated ground, the source is assumed to be distributed at a given depth (or between various depths) and extending outwards to an essentially infinite distance. In the case of exposure to contaminated air, the person is modeled as standing within a cloud of infinite, or semi-infinite, source distribution. However, these scenarios do not mimic common workplace environments where scatter off walls and ceilings may significantly alter the energy spectrum and dose coefficients. In this paper, dose rate coefficients were calculated using the International Commission on Radiological Protection (ICRP) reference voxel phantoms positioned in rooms of three sizes representing an office, laboratory, and warehouse. For each room size calculations using the reference phantoms were performed for photons, electrons, and positrons as the source particles to derive mono-energetic dose rate coefficients. Since the voxel phantoms lack the resolution to perform dose calculations at the sensitive depth for the skin, a mathematical phantom was developed and calculations were performed in each room size with the three source particle types. Coefficients for the noble gas radionuclides of ICRP Publication 107 (e.g., Ne, Ar, Kr, Xe, and Rn) were generated by folding the corresponding photon, electron, and positron emissions over the mono-energetic dose rate coefficients. Results indicate that the smaller room sizes have a significant impact on the dose rate per unit air concentration compared to the semi-infinite cloud case. For example, for Kr-85 the warehouse dose rate coefficient is 7% higher than the office dose rate coefficient while it is 71% higher for Xe-133. (orig.)

  3. Identification of Correlated GRACE Monthly Harmonic Coefficients Using Pattern Recognition and Neural Networks

    Science.gov (United States)

    Piretzidis, D.; Sra, G.; Sideris, M. G.

    2016-12-01

    This study explores new methods for identifying correlation errors in harmonic coefficients derived from monthly solutions of the Gravity Recovery and Climate Experiment (GRACE) satellite mission using pattern recognition and neural network algorithms. These correlation errors are evidenced in the differences between monthly solutions and can be suppressed using a de-correlation filter. In all studies so far, the implementation of the de-correlation filter starts from a specific minimum order (i.e., 11 for RL04 and 38 for RL05) until the maximum order of the monthly solution examined. This implementation method has two disadvantages, namely, the omission of filtering correlated coefficients of order less than the minimum order and the filtering of uncorrelated coefficients of order higher than the minimum order. In the first case, the filtered solution is not completely free of correlated errors, whereas the second case results in a monthly solution that suffers from loss of geophysical signal. In the present study, a new method of implementing the de-correlation filter is suggested, by identifying and filtering only the coefficients that show indications of high correlation. Several numerical and geometric properties of the harmonic coefficient series of all orders are examined. Extreme cases of both correlated and uncorrelated coefficients are selected, and their corresponding properties are used to train a two-layer feed-forward neural network. The objective of the neural network is to identify and quantify the correlation by providing the probability of an order of coefficients to be correlated. Results show good performance of the neural network, both in the validation stage of the training procedure and in the subsequent use of the trained network to classify independent coefficients. The neural network is also capable of identifying correlated coefficients even when a small number of training samples and neurons are used (e.g.,100 and 10, respectively).

  4. On separation of exchange term from the coefficient of the ...

    Indian Academy of Sciences (India)

    Home; Journals; Pramana – Journal of Physics; Volume 86; Issue 6 ... plus two coefficients of the electromechanical and magnetomechanical couplings, form the coefficient of magnetoelectromechanical coupling (CMEMC), a very important characteristic used for analysingmagnetoelectroelastic smart (composite) materials.

  5. Influence of roughness parameters on coefficient of friction under ...

    Indian Academy of Sciences (India)

    mm). Peak count. FD. Fractal dimension. Figure 3. Correlation coefficient between coefficient of friction and roughness parameters under lubricated conditions. White and black bars represent positive and negative correlations, respectively.

  6. Solution of heat equation with variable coefficient using derive

    CSIR Research Space (South Africa)

    Lebelo, RS

    2008-09-01

    Full Text Available are considered. The first one involves quadratic approximation of the variable coefficient by direct integration. This case is studied using a conic domain. The second case approximates the variable coefficient quadratically and by step functions. The solution...

  7. Prediction of octanol/water partition coefficient of selected ferrocene ...

    African Journals Online (AJOL)

    water partition coefficient of selected ferrocenes bearing different substituents, the calculation is based on the adaptation of the Rekker method. Our prediction of obtained theoretical partition coefficients values of logP for all studied substituted ...

  8. On separation of exchange term from the coefficient of the ...

    Indian Academy of Sciences (India)

    coefficients of the electromechanical and magnetomechanical couplings, form the coefficient of magnetoelectromechanical coupling (CMEMC), a very important characteristic used for analysing magnetoelectroelastic smart (composite) materials. It was analytically and graphically demon- strated that the CMEMC can have a ...

  9. Measurements of soil-solution distribution coefficient

    International Nuclear Information System (INIS)

    Tsukada, Hirofumi; Hasegawa, Hidenao; Hisamatsu, Shunichi; Sakurai, Naoyuki; Koyama, Kenji

    1999-01-01

    The soil-solution distribution coefficient (Kd) is defined as the ratio of element concentrations in a soil-solid phase to that in a solution phase. It is commonly used as an important parameter for transfer models of radionuclides in different environments, such as describing the migration behavior in the geosphere and transfer behavior in the biosphere. We plan to measure the Kd of elements by means of an extraction method in soils throughout Aomori Prefecture and to probe related factors affecting their variance. However, Kd values vary widely, dependent upon conditions of measurements even if a similar soil sample is measured. Therefore, measurement conditions for the Kd of elements were examined in the present study and the following conditions were adopted. A collected soil sample was passed through a 2 mm sieve and dried at 50degC. The ratio of solution to solid was 10. The mixture sample was shaken for 24 h at 20degC in a clean centrifuge bottle which was made of polypropylene copolymer (PPCO). According to the literature, common soil types in Aomori Prefecture are as follows: andosols in the Sanpachi-Kamikita region, gray lowland and upland soils in the Tsugaru region, sand-dune regosols in Kizukuri-machi, peat soils around lakes and so on. The Kd values for those soil types will be measured hereafter. (author)

  10. Townsend coefficients of gases in avalanche counters

    International Nuclear Information System (INIS)

    Brunner, G.

    1978-01-01

    Though much work has been done by many authors in the last few years in the development and application of avalanche counters for ion radiation, it is based upon values of the Townsend coefficients as the essential gas parameter, which were determined many years ago for much lower reduced field strengths F/p than prevail in such counters. Therefore absolute determinations of α in vapours of methyl alcohol, cyclohexane, acetone, and n-heptene were performed under original conditions of avalanche counters. The values obtained do not differ by more than 30%-50% from the former values indeed, extrapolated over F/p for the first three mentioned substances, but the amounts of A and B in the usual representation α/p=A exp(-B(F/p)) are much greater for the stronger reduced fields. This is of importance for such counter properties as the dependence of pulse heights on pressure, voltage, electrode distance etc., which are governed by other combinations of A and B than α/p itself. A comparison of results for different ionic radiations shows a marked influence of the primary ionization density along the particle tracks which is hard to explain. (Auth.)

  11. Coefficient of Friction of Human Corneal Tissue.

    Science.gov (United States)

    Wilson, Tawnya; Aeschlimann, Rudolf; Tosatti, Samuele; Toubouti, Youssef; Kakkassery, Joseph; Osborn Lorenz, Katherine

    2015-09-01

    A novel property evaluation methodology was used to determine the elusive value for the human corneal coefficient of friction (CoF). Using a microtribometer on 28 fresh human donor corneas with intact epithelia, the CoF was determined in 4 test solutions (≥5 corneas/solution): tear-mimicking solution (TMS) in borate-buffered saline (TMS-PS), TMS in phosphate-buffered saline (TMS-PBS), TMS with HEPES-buffered saline (TMS-HEPES), and tear-like fluid in PBS (TLF-PBS). Mean (SD) CoF values ranged from 0.006 to 0.015 and were 0.013 (0.010) in TMS-PS, 0.006 (0.003) in TMS-PBS, 0.014 (0.005) in TMS-HEPES, and 0.015 (0.009) in TLF-PBS. Statistically significant differences were shown for TMS-PBS versus TLF (P = 0.0424) and TMS-PBS versus TMS-HEPES (P = 0.0179), but not for TMS-PBS versus TMS-PS (P = 0.2389). Successful measurement of the fresh human corneal tissue CoF was demonstrated, with values differing in the evaluated buffer solutions, within this limited sample size.

  12. Volatilization: a soil degassing coefficient for iodine

    International Nuclear Information System (INIS)

    Sheppard, M.I.; Thibault, D.H.; Smith, P.A.; Hawkins, J.L.

    1994-01-01

    Iodine, an element essential to some animals, is ubiquitous in the biosphere. Unlike other metallic elements, molecular I is volatile, and other inorganic species present in aerated soils, such as I - and IO 3 - , may also volatilize as hydrides, hydrogen iodide (HI), or hydrogen iodates (HIO 3 , HIO 4 ). Methyl iodide has been measured in soils, and it is likely evolved from soils and plants. The long-lived radioisotope 129 I is abundant in nuclear wastes, and its high solubility in groundwater makes it an important element in the performance assessment of underground disposal facilities. Overestimates of soil I residence half-times by traditional foodchain models may be due to underestimation of volatilization. Field and lysimeter experiments over a 3-year period, and direct trapping experiments in the laboratory are reported. The results, combined with values from the literature, indicate the soil I degassing coefficient for a wide range of soil types, vegetated and bare, wet and dry, is lognormally distributed with a geometric mean of 2.1 x 10 -2 year -1 , a range of 1.8 x 10 -4 to 3.1 year -1 and a geometric standard deviation of 3.0. The results of a biosphere model simulation including degassing reduces soil I concentrations fivefold and increases air concentrations 25-fold at steady state, compared to simulations without degassing. (author)

  13. First-principles calculations of flexoelectric coefficients

    Science.gov (United States)

    Hong, Jiawang; Vanderbilt, David

    2013-03-01

    Flexoelectricity, which is the linear response of polarization to a strain gradient, can have a significant effect on the functional properties of dielectric thin films, superlattices and nanostructures. Despite growing experimental interest, there have been relatively few theoretical studies of flexoelectricity, especially in the context of first-principles calculations. In this talk, we present a complete theory of both the electronic (or ``frozen-ion'')[1] and lattice contributions to flexoelectricity, and demonstrate a supercell method for calculating the flexoelectric coefficients using first-principles density-functional methods. Results are presented for cubic materials including CsCl and SrTiO3. In order to obtain all the elements of the flexoelectric tensor, transverse as well as longitudinal, we carry out calculations on supercells extended along different orientations (e.g., [110] as well as [100]), taking special care to carry out conversions between objects calculated under fixed E or fixed D electric boundary conditions in different parts of the procedure. In this way, all the elements of both the electronic and lattice contributions to the flexoelectric tensor are determined.

  14. Automatic Subspace Learning via Principal Coefficients Embedding.

    Science.gov (United States)

    Peng, Xi; Lu, Jiwen; Yi, Zhang; Yan, Rui

    2017-11-01

    In this paper, we address two challenging problems in unsupervised subspace learning: 1) how to automatically identify the feature dimension of the learned subspace (i.e., automatic subspace learning) and 2) how to learn the underlying subspace in the presence of Gaussian noise (i.e., robust subspace learning). We show that these two problems can be simultaneously solved by proposing a new method [(called principal coefficients embedding (PCE)]. For a given data set , PCE recovers a clean data set from and simultaneously learns a global reconstruction relation of . By preserving into an -dimensional space, the proposed method obtains a projection matrix that can capture the latent manifold structure of , where is automatically determined by the rank of with theoretical guarantees. PCE has three advantages: 1) it can automatically determine the feature dimension even though data are sampled from a union of multiple linear subspaces in presence of the Gaussian noise; 2) although the objective function of PCE only considers the Gaussian noise, experimental results show that it is robust to the non-Gaussian noise (e.g., random pixel corruption) and real disguises; and 3) our method has a closed-form solution and can be calculated very fast. Extensive experimental results show the superiority of PCE on a range of databases with respect to the classification accuracy, robustness, and efficiency.

  15. Transfer coefficients in elliptical tubes and plate fin heat exchangers

    International Nuclear Information System (INIS)

    Saboya, S.M.

    1979-09-01

    Mean transfer coefficients in elliptical tubes and plate fin heat exchangers were determined by application of heat and mass transfer analogy in conjunction with the naphthalene sublimation technique. The transfer coefficients are presented in a dimensionless form as functions of the Reynolds number. By using the least squares method analytical expressions for the transfer coefficients were determined with low scattering. (E.G.) [pt

  16. On Estimation and Hypothesis Testing Problems for Correlation Coefficients

    Science.gov (United States)

    Kraemer, Helena Chmura

    1975-01-01

    A selection of statistical problems commonly encountered in psychological or psychiatric research concerning correlation coefficients are re-evaluated in the light of recently developed simplifications in the forms of the distribution theory of the intraclass correlation coefficient, of the product-moment correlation coefficient, and the Spearman…

  17. Higher Education Exchange, 2010

    Science.gov (United States)

    Brown, David W., Ed.; Witte, Deborah, Ed.

    2010-01-01

    "Higher Education Exchange" publishes case studies, analyses, news, and ideas about efforts within higher education to develop more democratic societies. Contributors to this issue of the "Higher Education Exchange" examine whether institutions of higher learning are doing anything to increase the capacity of citizens to shape their future.…

  18. Higher Education Exchange, 2012

    Science.gov (United States)

    Brown, David W., Ed.; Witte, Deborah, Ed.

    2012-01-01

    "Higher Education Exchange" publishes case studies, analyses, news, and ideas about efforts within higher education to develop more democratic societies. Contributors to this issue of the "Higher Education Exchange" examine whether institutions of higher learning are doing anything to increase the capacity of citizens to shape…

  19. Higher Education Exchange, 2011

    Science.gov (United States)

    Brown, David W., Ed.; Witte, Deborah, Ed.

    2011-01-01

    "Higher Education Exchange" publishes case studies, analyses, news, and ideas about efforts within higher education to develop more democratic societies. Contributors to this issue of the "Higher Education Exchange" examine whether institutions of higher learning are doing anything to increase the capacity of citizens to shape…

  20. Higher Education Exchange, 2014

    Science.gov (United States)

    Brown, David W., Ed.; Witte, Deborah, Ed.

    2014-01-01

    Research shows that not only does higher education not see the public; when the public, in turn, looks at higher education, it sees mostly malaise, inefficiencies, expense, and unfulfilled promises. Yet, the contributors to this issue of the "Higher Education Exchange" tell of bright spots in higher education where experiments in working…

  1. Estimates of effective population size and inbreeding in South African indigenous chicken populations: implications for the conservation of unique genetic resources.

    Science.gov (United States)

    Mtileni, Bohani; Dzama, Kennedy; Nephawe, Khathutshelo; Rhode, Clint

    2016-06-01

    diversity ascribed to population differences within groups (F SC = 0.106). The results suggest that significant genetic erosion has occurred within the conservation flocks due to inbreeding, pronounced effects of random drift and selection. It might be necessary to introduce new breeding individuals from the respective field populations in order to increase the effective population sizes of the conservation flocks and counter the effects of genetic erosion.

  2. Transfer coefficients for terrestrial foodchain: their derivation and limitations

    International Nuclear Information System (INIS)

    Ng, Y.C.; Colsher, C.S.; Thompson, S.E.

    1979-01-01

    Transfer coefficients to predict the passage of isotopes from the environment to terrestrial foods have been derived for various radionuclides of importance in the nuclear fuel cycle. These data update and extend previously recommended handbook values. We derive transfer coefficients to terrestrial foods and describe the systematics of the derived transfer coefficients. Suggestions are offered for changes in the values of transfer coefficients to terrestrial foods that now appear in federal regulatory guides. Deficiencies in our present knowledge concerning transfer coefficients and limitations in the use of these values to ensure compliance with radiation protection standards are discussed

  3. Changes in Electrokinetic Coupling Coefficients of Granite under Triaxial Deformation

    Directory of Open Access Journals (Sweden)

    Osamu Kuwano

    2012-01-01

    Full Text Available Electrokinetic phenomena are believed to be the most likely origin of electromagnetic signals preceding or accompanying earthquakes. The intensity of the source current due to the electrokinetic phenomena is determined by the fluid flux and the electrokinetic coupling coefficient called streaming current coefficient; therefore, how the coefficient changes before rupture is essential. Here, we show how the electrokinetic coefficients change during the rock deformation experiment up to failure. The streaming current coefficient did not increase before failure, but continued to decrease up to failure, which is explained in terms of the elastic closure of capillary. On the other hand, the streaming potential coefficient, which is the product of the streaming current coefficient and bulk resistivity of the rock, increased at the onset of dilatancy. It may be due to change in bulk resistivity. Our result indicates that the zeta potential of the newly created surface does not change so much from that of the preexisting fluid rock interface.

  4. The effect of chalk on the finger-hold friction coefficient in rock climbing.

    Science.gov (United States)

    Amca, Arif Mithat; Vigouroux, Laurent; Aritan, Serdar; Berton, Eric

    2012-11-01

    The main purpose of this study was to examine the effect of chalk on the friction coefficient between climber's fingers and two different rock types (sandstone and limestone). The secondary purpose was to investigate the effects of humidity and temperature on the friction coefficient and on the influence of chalk. Eleven experienced climbers took part in this study and 42 test sessions were performed. Participants hung from holds which were fixed on a specially designed hang board. The inclination of the hang board was progressively increased until the climber's hand slipped from the holds. The angle of the hang board was simultaneously recorded by using a gyroscopic sensor and the friction coefficient was calculated at the moment of slip. The results showed that there was a significant positive effect of chalk on the coefficient of friction (+18.7% on limestone and +21.6% on sandstone). Moreover sandstone had a higher coefficient of friction than limestone (+15.6% without chalk, +18.4% with chalk). These results confirmed climbers' belief that chalk enhances friction. However, no correlation with humidity/temperature and friction coefficient was noted which suggested that additional parameters should be considered in order to understand the effects of climate on finger friction in rock climbing.

  5. Absorbed Internal Dose Conversion Coefficients for Domestic Reference Animals and Plant

    International Nuclear Information System (INIS)

    Keum, Dong Kwon; Jun, In; Lim, Kwang Muk; Choi, Yong Ho

    2010-01-01

    This paper describes the methodology of calculating the internal dose conversion coefficient in order to assess the radiological impact on non-human species. This paper also presents the internal dose conversion coefficients of 25 radionuclides ( 3 H, 7 Be, 14 C, 40 K, 51 Cr, 54 Mn, 59 Fe, 58 Co, 60 Co, 65 Zn, 90 Sr, '9 5 Zr, 95 Nb, 99 Tc, 106 Ru, 129 I, 131 I, 136 Cs, 137 Cs, 140 Ba, 140 La, 144 Ce, 238 U, 239 Pu, 240 Pu) for domestic seven reference animals (roe deer, rat, frog, snake, Chinese minnow, bee, and earthworm) and one reference plant (pine tree). The uniform isotropic model was applied in order to calculate the internal dose conversion coefficients. The calculated internal dose conversion coefficient (μGyd -1 per Bqkg -1 ) ranged from 10 -6 to 10 -2 according to the type of radionuclides and organisms studied. It turns out that the internal does conversion coefficient was higher for alpha radionuclides, such as 238 U, 239 Pu, and 240 Pu, and for large organisms, such as roe deer and pine tree. The internal dose conversion coefficients of 239 Pu, 240 Pu, 238 U, 14 C, 3 H and 99 Tc were independent of the organism

  6. Absorbed Internal Dose Conversion Coefficients for Domestic Reference Animals and Plant

    Energy Technology Data Exchange (ETDEWEB)

    Keum, Dong Kwon; Jun, In; Lim, Kwang Muk; Choi, Yong Ho [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2010-02-15

    This paper describes the methodology of calculating the internal dose conversion coefficient in order to assess the radiological impact on non-human species. This paper also presents the internal dose conversion coefficients of 25 radionuclides ({sup 3}H, {sup 7}Be, {sup 14}C, {sup 40}K, {sup 51}Cr, {sup 54}Mn, {sup 59}Fe, {sup 58}Co, {sup 60}Co, {sup 65}Zn, {sup 90}Sr, '9{sup 5}Zr, {sup 95}Nb, {sup 99}Tc, {sup 106}Ru, {sup 129}I, {sup 131}I, {sup 136}Cs, {sup 137}Cs, {sup 140}Ba, {sup 140}La, {sup 144}Ce, {sup 238}U, {sup 239}Pu, {sup 240}Pu) for domestic seven reference animals (roe deer, rat, frog, snake, Chinese minnow, bee, and earthworm) and one reference plant (pine tree). The uniform isotropic model was applied in order to calculate the internal dose conversion coefficients. The calculated internal dose conversion coefficient (muGyd{sup -1} per Bqkg{sup -1}) ranged from 10{sup -6} to 10{sup -2} according to the type of radionuclides and organisms studied. It turns out that the internal does conversion coefficient was higher for alpha radionuclides, such as {sup 238}U, {sup 239}Pu, and {sup 240}Pu, and for large organisms, such as roe deer and pine tree. The internal dose conversion coefficients of {sup 239}Pu, {sup 240}Pu, {sup 238}U, {sup 14}C, {sup 3}H and {sup 99}Tc were independent of the organism

  7. Estimation of radon emanation coefficient for representative soils in Okinawa, Japan.

    Science.gov (United States)

    Shiroma, Y; Hosoda, M; Ishikawa, T; Sahoo, S K; Tokonami, S; Furukawa, M

    2015-11-01

    Radon ((222)Rn) emanation coefficients for the representative soils distributed in Okinawa Island, Japan, have been estimated empirically. Arithmetic means of the emanation coefficients for dry and moist conditions were calculated to be 0.19 and 0.29, respectively. In Okinawa, the soils are traditionally classified into three types, namely the dark red soils, the residual regosols and the red and yellow soils. The dark red soils have relatively high coefficients. The residual regosols and the red and yellow soils have relatively low coefficients. To investigate the variable factor of the emanation coefficients, analyses of radioactive elements and physical properties have also been performed on the soils. For the dark red soils, the contents of the fine particle and the (226)Ra are relatively higher than those for the other soils. Based on these results, it is suggested that the variation in the radon emanation coefficient is mainly regulated by the (226)Ra concentration, the particle sizes and the water contents of the soils. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  8. Determination of water diffusion coefficient by gamma radiation and thermal shock

    International Nuclear Information System (INIS)

    Crausse, P.; Lemarchand, D.

    1985-01-01

    Mass transfer coefficient of water in a porous material (baked clay) is determined by gamma ray attenuation (from a Cs135 source) and thermal shock. Water content is found higher by thermal shock, difference obtained between the two methods is discussed. 7 refs [fr

  9. Classification of categories with matrices of coefficient 2 and order n

    KAUST Repository

    Allouch, Samer

    2017-12-15

    In this paper, we present the categories associated to the square matrix with coefficients 2 of order 3. The family of categories associated to these matrices has five isomorphism classes. In the case of a matrix of order higher than 3, we only demonstrate upper and lower bounds for the number of associated categories.

  10. The Evolution of Human Intelligence and the Coefficient of Additive Genetic Variance in Human Brain Size

    Science.gov (United States)

    Miller, Geoffrey F.; Penke, Lars

    2007-01-01

    Most theories of human mental evolution assume that selection favored higher intelligence and larger brains, which should have reduced genetic variance in both. However, adult human intelligence remains highly heritable, and is genetically correlated with brain size. This conflict might be resolved by estimating the coefficient of additive genetic…

  11. Evaluating Force-Field London Dispersion Coefficients Using the Exchange-Hole Dipole Moment Model.

    Science.gov (United States)

    Mohebifar, Mohamad; Johnson, Erin R; Rowley, Christopher N

    2017-12-12

    London dispersion interactions play an integral role in materials science and biophysics. Force fields for atomistic molecular simulations typically represent dispersion interactions by the 12-6 Lennard-Jones potential using empirically determined parameters. These parameters are generally underdetermined, and there is no straightforward way to test if they are physically realistic. Alternatively, the exchange-hole dipole moment (XDM) model from density-functional theory predicts atomic and molecular London dispersion coefficients from first principles, providing an innovative strategy to validate the dispersion terms of molecular-mechanical force fields. In this work, the XDM model was used to obtain the London dispersion coefficients of 88 organic molecules relevant to biochemistry and pharmaceutical chemistry and the values compared with those derived from the Lennard-Jones parameters of the CGenFF, GAFF, OPLS, and Drude polarizable force fields. The molecular dispersion coefficients for the CGenFF, GAFF, and OPLS models are systematically higher than the XDM-calculated values by a factor of roughly 1.5, likely due to neglect of higher order dispersion terms and premature truncation of the dispersion-energy summation. The XDM dispersion coefficients span a large range for some molecular-mechanical atom types, suggesting an unrecognized source of error in force-field models, which assume that atoms of the same type have the same dispersion interactions. Agreement with the XDM dispersion coefficients is even poorer for the Drude polarizable force field. Popular water models were also examined, and TIP3P was found to have dispersion coefficients similar to the experimental and XDM references, although other models employ anomalously high values. Finally, XDM-derived dispersion coefficients were used to parametrize molecular-mechanical force fields for five liquids-benzene, toluene, cyclohexane, n-pentane, and n-hexane-which resulted in improved accuracy in the

  12. Roughness coefficient and its uncertainty in gravel-bed river

    Directory of Open Access Journals (Sweden)

    Ji-Sung Kim

    2010-06-01

    Full Text Available Manning's roughness coefficient was estimated for a gravel-bed river reach using field measurements of water level and discharge, and the applicability of various methods used for estimation of the roughness coefficient was evaluated. Results show that the roughness coefficient tends to decrease with increasing discharge and water depth, and over a certain range it appears to remain constant. Comparison of roughness coefficients calculated by field measurement data with those estimated by other methods shows that, although the field-measured values provide approximate roughness coefficients for relatively large discharge, there seems to be rather high uncertainty due to the difference in resultant values. For this reason, uncertainty related to the roughness coefficient was analyzed in terms of change in computed variables. On average, a 20% increase of the roughness coefficient causes a 7% increase in the water depth and an 8% decrease in velocity, but there may be about a 15% increase in the water depth and an equivalent decrease in velocity for certain cross-sections in the study reach. Finally, the validity of estimated roughness coefficient based on field measurements was examined. A 10% error in discharge measurement may lead to more than 10% uncertainty in roughness coefficient estimation, but corresponding uncertainty in computed water depth and velocity is reduced to approximately 5%. Conversely, the necessity for roughness coefficient estimation by field measurement is confirmed.

  13. India's Higher Education Challenges

    Science.gov (United States)

    Altbach, Philip G.

    2014-01-01

    India, with the world's second largest higher education system and a rapidly growing economy as one of the BRIC nations, faces significant challenges in building both capacity and excellence in higher education. India's higher education system is characterized by "islands of excellence in a sea of mediocrity." The mainstream universities…

  14. Globalisation and Higher Education

    NARCIS (Netherlands)

    Marginson, Simon; van der Wende, Marijk

    2007-01-01

    Economic and cultural globalisation has ushered in a new era in higher education. Higher education was always more internationally open than most sectors because of its immersion in knowledge, which never showed much respect for juridical boundaries. In global knowledge economies, higher education

  15. Identification of bearing supports' force coefficients from rotor responses due to imbalances and impact loads

    Science.gov (United States)

    de Santiago Duran, Oscar Cesar

    Experimental identification of fluid film bearing parameters is vital to validate predictions from often restrictive computational fluid film bearing models and is also promising for condition monitoring and troubleshooting. This dissertation presents the analytical bases of two procedures for bearing supports parameter identification with potential for in-situ implementation. Bearing support coefficients are derived from measurements of rotor responses to impact loads and due to calibrated imbalances in characteristic planes. Subsequent implementation of the procedures to measurements performed in a rigid massive rotor traversing two critical speeds provides force coefficients for a novel bearing support comprising a tilting pad bearing (TPJB ) in series with an integral squeeze film damper (SFD). At a constant rotor speed, the first method requires impacts loads exerted along two lateral planes for identification of frequency-dependent force coefficients. Simulation numerical examples show the method is reliable with a reduced sensitivity to noise as the number of impacts increases (frequency averaging). In the experiments, an ad-hoc fixture delivers impacts to the rotor middle disk at speeds of 2,000 and 4,000 rpm. The experimentally identified force coefficients are in close agreement with predicted coefficients for the series support TPJB-SFD. In particular, damping coefficients are best identified around the system first natural frequency. Bearing stiffness are correctly identified in the low frequency range, but show a marked reduction at higher frequencies apparently due to inertial effects not accounted for in the model. Measurements of rotor response to calibrated imbalances allow identification of speed-dependent force coefficients. The procedure requires a minimum of two different imbalance distributions for identification of force coefficients from the two bearing supports. The rotor responses show minimal cross-coupling effects, as also predicted by

  16. Experimental determination of the distributed dynamic coefficients for a hydrodynamic fluid film bearing

    Science.gov (United States)

    Gyurko, John Harrison

    Most current rotor bearing analysis utilizes lumped parameter bearing coefficients to model the static and dynamic characteristics of fluid film bearings. By treating the stiffness and damping properties of the fluid film as acting upon the axial centerline of the rotor, these models are limited in their analysis to first order lateral rotor-bearing motion. The development of numerical methods that distribute the dynamic properties of the fluid film around the bearing circumference allow for higher order analysis of the motion between the bearing and rotor. Assessment of the accuracy of the numerical method used to calculate distributed dynamic fluid film bearing coefficients is performed by developing a novel hydrodynamic journal bearing test rig and experimental testing procedure capable of obtaining measured distributed dynamic coefficients over a range of bearing operating conditions. The instrumented bearing test rig is used to measure the dynamic bearing displacement and fluid film pressure responses from application of an externally applied excitation force. Least squares solution to a system of perturbated pressure equations, populated by measured displacement and pressure responses, is used to determine the hydrodynamic stiffness and damping properties for a finite region of the bearing surface. Incremental rotation of pressure sensors embedded in the body of the test bearing allow for measurement of the fluid film circumferential pressure distribution which is used to calculate a set of experimentally determined dynamic bearing coefficients. Distributed bearing coefficients derived from experimental measurements are compared to numerically calculated distributed coefficients as well as to lumped parameter coefficients generated from experimental and numerical methods found in the literature. Overall, the numerically calculated distributed coefficients successfully model both the circumferential distribution and the operating conditions of the experimental

  17. Properties of C4F7N–CO2 thermal plasmas: thermodynamic properties, transport coefficients and emission coefficients

    Science.gov (United States)

    Wu, Yi; Wang, Chunlin; Sun, Hao; Murphy, Anthony B.; Rong, Mingzhe; Yang, Fei; Chen, Zhexin; Niu, Chunpin; Wang, Xiaohua

    2018-04-01

    The thermophysical properties, including composition, thermodynamic properties, transport coefficients and net emission coefficients, of thermal plasmas formed from pure iso-C4 perfluoronitrile C4F7N and C4F7N–CO2 mixtures are calculated for temperatures from 300 to 30 000 K and pressures from 0.1 to 20 atm. These gases have received much attention as alternatives to SF6 for use in circuit breakers, due to the low global warming potential and good dielectric properties of C4F7N. Since the parameters of the large molecules formed in the dissociation of C4F7N are unavailable, the partition function and enthalpy of formation were calculated using computational chemistry methods. From the equilibrium composition calculations, it was found that when C4F7N is mixed with CO2, CO2 can capture C atoms from C4F7N, producing CO, since the system consisting of small molecules such as CF4 and CO has lower energy at room temperature. This is in agreement with previous experimental results, which show that CO dominates the decomposition products of C4F7N–CO2 mixtures; it could limit the repeated breaking performance of C4F7N. From the point of view of chemical stability, the mixing ratio of CO2 should therefore be chosen carefully. Through comparison with common arc quenching gases (including SF6, CF3I and C5F10O), it is found that for the temperature range for which electrical conductivity remains low, pure C4F7N has similar ρC p (product of mass density and specific heat) properties to SF6, and higher radiative emission coefficient, properties that are correlated with good arc extinguishing capability. For C4F7N–CO2 mixtures, the electrical conductivity is very close to that of SF6 while the ρC p peak at 7000 K caused by decomposition of CO implies inferior interruption capability to that of SF6. The calculated properties will be useful in arc simulations.

  18. Efficient computation of aerodynamic influence coefficients for aeroelastic analysis on a transputer network

    Science.gov (United States)

    Janetzke, David C.; Murthy, Durbha V.

    1991-01-01

    Aeroelastic analysis is multi-disciplinary and computationally expensive. Hence, it can greatly benefit from parallel processing. As part of an effort to develop an aeroelastic capability on a distributed memory transputer network, a parallel algorithm for the computation of aerodynamic influence coefficients is implemented on a network of 32 transputers. The aerodynamic influence coefficients are calculated using a 3-D unsteady aerodynamic model and a parallel discretization. Efficiencies up to 85 percent were demonstrated using 32 processors. The effect of subtask ordering, problem size, and network topology are presented. A comparison to results on a shared memory computer indicates that higher speedup is achieved on the distributed memory system.

  19. Modified Regression Correlation Coefficient for Poisson Regression Model

    Science.gov (United States)

    Kaengthong, Nattacha; Domthong, Uthumporn

    2017-09-01

    This study gives attention to indicators in predictive power of the Generalized Linear Model (GLM) which are widely used; however, often having some restrictions. We are interested in regression correlation coefficient for a Poisson regression model. This is a measure of predictive power, and defined by the relationship between the dependent variable (Y) and the expected value of the dependent variable given the independent variables [E(Y|X)] for the Poisson regression model. The dependent variable is distributed as Poisson. The purpose of this research was modifying regression correlation coefficient for Poisson regression model. We also compare the proposed modified regression correlation coefficient with the traditional regression correlation coefficient in the case of two or more independent variables, and having multicollinearity in independent variables. The result shows that the proposed regression correlation coefficient is better than the traditional regression correlation coefficient based on Bias and the Root Mean Square Error (RMSE).

  20. Object detection by correlation coefficients using azimuthally averaged reference projections.

    Science.gov (United States)

    Nicholson, William V

    2004-11-01

    A method of computing correlation coefficients for object detection that takes advantage of using azimuthally averaged reference projections is described and compared with two alternative methods-computing a cross-correlation function or a local correlation coefficient versus the azimuthally averaged reference projections. Two examples of an application from structural biology involving the detection of projection views of biological macromolecules in electron micrographs are discussed. It is found that a novel approach to computing a local correlation coefficient versus azimuthally averaged reference projections, using a rotational correlation coefficient, outperforms using a cross-correlation function and a local correlation coefficient in object detection from simulated images with a range of levels of simulated additive noise. The three approaches perform similarly in detecting macromolecular views in electron microscope images of a globular macrolecular complex (the ribosome). The rotational correlation coefficient outperforms the other methods in detection of keyhole limpet hemocyanin macromolecular views in electron micrographs.