scholarly journals Asteroseismology of the DAV star R808

2020 ◽  
Vol 500 (4) ◽  
pp. 4703-4709
Author(s):  
Y H Chen ◽  
H Shu
Keyword(s):  
Coulomb Potential ◽  
Model Fitting ◽  
Potential Effect ◽  
Data Set ◽  
Trapped Mode ◽  
Star Models ◽  
Diffusion Scheme ◽  
Best Fitting ◽  
Screened Coulomb Potential ◽  
Fitting Model

ABSTRACT The DAV star R808 was observed by 13 different telescopes for more than 170 h in 2009 April on the WET run XCOV26. 25 independent pulsation frequencies were identified by this data set. We assumed 19 m = 0 modes and performed an asteroseismological study on those 19 modes. We evolve grids of DAV star models by wdec adopting the element diffusion scheme with pure and screened Coulomb potential effect. The core compositions are from white dwarf models evolved by mesa, which are thermal nuclear burning results. Our best-fitting model is from the screened Coulomb potential scenario, which has parameters of log(MHe/M*) = −2.4, log(MH/M*) = −5.2, Teff = 11100 K, M* = 0.710 M⊙, logg = 8.194, and σRMS = 2.86 s. The value of σRMS is the smallest among the four existing asteroseismological work. The average period spacing is 46.299 s for l = 1 modes and 25.647 s for l = 2 modes. The other six observed modes can be fitted by $m\, \ne$ 0 components of some modes for our best-fitting model. Fitting the 25 observed modes, we obtain a σRMS value of 2.59 s. Considering the period spacings, we also assume, that at least in one case, we detect an l = 2 trapped mode.

scholarly journals Application of the screened Coulomb potential to fit the DA-type variable star HS 0507 + 0434B

2020 ◽  
Vol 495 (2) ◽  
pp. 2428-2435 ◽  
Author(s):  
Y H Chen
Keyword(s):  
Coulomb Potential ◽  
The Core ◽  
Star Models ◽  
Pure Coulomb ◽  
Type Variable ◽  
Diffusion Scheme ◽  
Best Fitting ◽  
Composition Profiles ◽  
Screened Coulomb Potential ◽  
Coulomb Potentials

ABSTRACT wdec is used to evolve grids of DA-variable (DAV) star models adopting the element diffusion scheme with pure and screened Coulomb potentials. The core compositions are thermonuclear burning results derived from mesa. mesa yields composition profiles that the version of wdec used in this work could not accommodate (most notably, the presence of helium in the core of the model). According to the theory of rotational splitting, Fu and colleagues identified six triplets for the DAV star HS 0507 + 0434B based on 206 h of photometric data. The grids of DAV star models are used to fit the six reliable m = 0 modes. When adopting the screened Coulomb potential, a best-fitting model of log(MHe/M*) = −3.0, log(MH/M*) = −6.1, Teff = 11 790 K, M* = 0.625 M⊙, log g = 8.066 and σRMS = 2.08 s was obtained. Compared with adopting the pure Coulomb potential, the value of σRMS is improved by 34 per cent. This study may provide a new method for research into mode-trapping properties.

The inverse problem of resistivity sounding

Geophysics ◽  
1984 ◽  
Vol 49 (12) ◽  
pp. 2143-2158 ◽  
Author(s):  
Robert L. Parker
Keyword(s):  
Inverse Problem ◽  
Apparent Resistivity ◽  
Single Point ◽  
Quadratic Program ◽  
Data Set ◽  
Regularization Technique ◽  
Resistivity Sounding ◽  
Best Fitting ◽  
Electrical Data ◽  
Fitting Model

The electric potential due to a single point electrode at the surface of a layered conducting medium is calculated by means of a linear combination of the potentials associated with a set of two‐layer systems. This new representation is called the bilayer expansion for the Green’s function. It enables the forward problem of resistivity sounding to be solved very efficiently, even for complicated profiles. Also, the bilayer expansion facilitates the solution of the resistivity inverse problem: the coefficients in the expansion are linearly related to apparent resistivity as it is measured and they are readily mapped into parameters for a model. Specifically, I consider models comprising uniformly conducting layers of equal thickness; for a given finite data set a quadratic program can be used to find the best‐fitting model in this class for any specified thickness. As the thickness is reduced, models of this kind can approximate arbitrary profiles with unlimited accuracy. If there is a model that satisfies the data well, there are other models equally good or better whose variation takes place in an infinitesimally thin zone near the surface, below which there is a perfectly conducting region. This extraordinary class of solutions underscores the serious ambiguity in the interpretation of apparent resistivity data. It is evident that strong constraints from outside the electrical data set must be applied if reliable solutions are to be discovered. Previous work seems to have given a somewhat overly optimistic impression of the resolving abilities of this kind of data. I consider briefly a regularization technique designed to maximize the smoothness of models found with the bilayer inversion.

scholarly journals Heritability of Schneider's first-rank symptoms

2002 ◽  
Vol 180 (1) ◽  
pp. 35-38 ◽  
Author(s):  
Alastair G. Cardno ◽  
Pak C. Sham ◽  
Anne E. Farmer ◽  
Robin M. Murray ◽  
Peter McGuffin
Keyword(s):  
Model Fitting ◽  
Heritability Estimate ◽  
Best Fitting ◽  
Same Gender ◽  
First Rank Symptoms ◽  
Fitting Model ◽  
Biometric Model

BackgroundSchneider's first-rank symptoms are given particular weight when making a diagnosis of schizophrenia, but the nuclear syndrome, characterised by one or more first-rank symptoms, has been found previously to have no heritability.AimsTo estimate the heritability of the nuclear syndrome.MethodA total of 224 twin pairs (106 monozygotic, 118 same-gender dizygotic) were ascertained from the Maudsley Twin Register in London via probands with any psychosis. Lifetime-ever first-rank symptoms were rated using the OPCRIT checklist. Probandwise concordance rates were calculated for the nuclear syndrome and a heritability estimate was derived from biometric model fitting.ResultsProbandwise concordance rates were 13/49 (26.5%) for monozygotic and 0/45 to 2/46 (0.0–4.3%) for dizygotic pairs. The heritability estimate for the best-fitting model was 71% (95% CI 57–82).ConclusionsThese results indicate that the nuclear syndrome shows substantial heritability, although this is slightly lower than that for schizophrenia as defined by the DSM and ICD systems.

Feeling of Cold Hands and Feet is a Highly Heritable Phenotype

2012 ◽  
Vol 15 (2) ◽  
pp. 166-169 ◽  
Author(s):  
Yoon-Mi Hur ◽  
Jeong-Ho Chae ◽  
Ki Wha Chung ◽  
Jung Jin Kim ◽  
Hoe-Uk Jeong ◽  
...  
Keyword(s):  
Sex Differences ◽  
Measurement Error ◽  
General Population ◽  
Environmental Influences ◽  
Model Fitting ◽  
Environmental Variance ◽  
Best Fitting ◽  
Heritable Phenotype ◽  
Hands And Feet ◽  
Fitting Model

The prevalence of the feeling of cold hands and feet (FCHF) is high in the general population but the etiology of FCHF is largely unknown. The aim of the present study was to explore whether the FCHF is heritable. Eight hundred and ninety-four pairs of twins completed a question about FCHF. Tetrachoric correlations for FCHF were .58, .29, .67, .52, and .04 for monozygotic male, dizygotic male, monozygotic female, and dizygotic female twins, respectively. Model-fitting analyses suggested that in the best fitting model, additive genetic and nonshared environmental variance including measurement error were 64% (95% CI: 55%-72%) and 36% (28%-45%), respectively. Sex differences in genetic and environmental influences were not significant.

Asteroseismological Analysis of the DAV HS 0507+0434B: The Influence of Chemical Profile on the Pulsation Periods

2021 ◽  
Vol 922 (2) ◽  
pp. 138
Author(s):  
Lin Guifang ◽  
Su Jie ◽  
Li Yan ◽  
Fu Jianning
Keyword(s):  
Iteration Method ◽  
Mass Fraction ◽  
Chemical Structure ◽  
Inner Core ◽  
Chemical Profile ◽  
Fundamental Parameters ◽  
Trapped Mode ◽  
Core Profile ◽  
Best Fitting ◽  
Fitting Model

Abstract Asteroseismology is a powerful tool to infer the details of the inner chemical structure of white dwarfs. Using the nine observed frequencies of HS 0507+0434B, we explore the influence of the inner chemical profile on the pulsation periods. Based on the evolutionary C/O profile, we modify slightly the C/O core profile and make an asteroseismic analysis for HS 0507+0434B. We find that the trapped mode with the period of 445.3 s is mainly affected by the hydrogen and helium mass fraction. The inner C/O core profile has an influence on all modes extending into the inner core. When we use the iteration method with the optimal C/O core profile, the fit between the theoretical periods and observed ones is significantly improved. For the best-fitting model with the optimal parametric C/O core, there is a smaller C/O ratio and a smaller overshooting zone in the stellar interior. The fundamental parameters of the model with the optimal C/O core are M */M ⊙ ∼ 0.710 ± 0.005, T eff ∼ 12570 ± 106K, log M H / M * ∼ − 8.01 ± 0.08 , and log M He / M * ∼ − 2.51 ± 0.08 .

A quantitative genetic analysis of schizotypal personality traits

2003 ◽  
Vol 33 (5) ◽  
pp. 803-816 ◽  
Author(s):  
Y. M. LINNEY ◽  
R. M. MURRAY ◽  
E. R. PETERS ◽  
A. M. MacDONALD ◽  
F. RIJSDIJK ◽  
...  
Keyword(s):  
Structural Equation ◽  
Model Fitting ◽  
Twin Studies ◽  
Equation Model ◽  
Common Pathway ◽  
Schizotypal Personality ◽  
Quantitative Genetic ◽  
Best Fitting ◽  
Limited Power ◽  
Fitting Model

Background. Previous twin studies investigating the heritability of schizotypy have often had limited power and have failed to measure the disorganization/social anxiety component.Method. Seven hundred and thirty-three female twin pairs, drawn from the Institute of Psychiatry Volunteer Twin Register, completed the Oxford–Liverpool Inventory of Feelings and Experiences and the Peters et al. Delusions Inventory. Structural equation modelling was carried out on scores for MZ and DZ twin pairs.Results. The best fitting models for all scales comprised additive genetic and unique environmental effects. Heritability was estimated at approximately 50% for most scales, although it was lower at 37% for the PDI scale. Multivariate structural equation model fitting revealed a best-fitting model in which additive genetic and unique environmental influences act through a single common pathway for Cognitive Disorganization, Unusual Experiences and the PDI, and through a separate common pathway for Cognitive Disorganization and Introvertive Anhedonia.Conclusions. The various components of schizotypy are moderately heritable. Multivariate model fitting indicates that at least two latent factor structures are required to account for the covariation between the various components of schizotypy. The positive and negative components of schizotypy are relatively genetically independent, although each in turn may be related to Cognitive Disorganization.

165 Effects of Digestible Lysine Level on Growth Performance and Economics of Grow-finish Pigs

2021 ◽  
Vol 99 (Supplement_1) ◽  
pp. 58-59
Author(s):  
Larissa L Becker ◽  
Emily E Scholtz ◽  
Joel M DeRouchey ◽  
Mike D Tokach ◽  
Jason C Woodworth ◽  
...  
Keyword(s):  
Phase 1 ◽  
Information Criterion ◽  
Response Curves ◽  
Phase 3 ◽  
Ileal Digestibility ◽  
Distillers Dried Grains ◽  
Feed Cost ◽  
Best Fitting ◽  
Dietary Treatments ◽  
Fitting Model

Abstract A total of 2,124 barrows and gilts (PIC 1050′DNA 600, initially 48.9 kg) were used in a 32-d study to determine the optimal dietary standardized ileal digestibility (SID) Lys level in a commercial setting. Pigs were randomly allotted to 1 of 5 dietary treatments with 24 to 27 pigs/pen and 16 replications/treatment. Similar number of barrows and gilts were placed in each pen. Diets were fed over 3 phases (48.9 to 58.6, 58.6 to 70.9, and 70.9 to 80.8 kg respectively). Dietary treatments were corn-soybean meal-based and contained 10 (phase 1 and 2) or 5% (phase 3) distillers dried grains with solubles. Diets were formulated to 85, 95, 103, 110, or 120% of the current Pig Improvement Company (PIC, Hendersonville, TN) SID Lys gilt recommendations with phase 1 SID Lys levels of 0.90, 1.01, 1.09, 1.17 and 1.27%, phase 2 levels of 0.79, 0.87, 0.94, 1.03, and 1.10%, and phase 3 levels of 0.71, 0.78, 0.85, 0.92, and 0.99%, respectively. Dose response curves were evaluated using linear (LM), quadratic polynomial (QP), broken-line linear (BLL), and broken-line quadratic (BLQ) models. For each response variable, the best-fitting model was selected using the Bayesian information criterion. Overall (d 0 to 32), increasing SID Lys increased (linear, P< 0.001) BW, ADG, G:F, Lys intake/d, and Lys intake/kg of gain. Modeling margin over feed cost (MOFC), BLL and QP estimated the requirement at 105.8% and 113.7% respectively. In summary, while growth increased linearly up to 120% of the PIC current feeding level, the optimal MOFC was 106% to 114% depending on the model used.

Genetic and Environmental Influences of Dietary Indices in a UK Female Twin Cohort

2020 ◽  
Vol 23 (6) ◽  
pp. 330-337
Author(s):  
Olatz Mompeo ◽  
Rachel Gibson ◽  
Paraskevi Christofidou ◽  
Tim D. Spector ◽  
Cristina Menni ◽  
...  
Keyword(s):  
Healthy Eating ◽  
Menopausal Status ◽  
Healthy Eating Index ◽  
Healthy Diet ◽  
Nutritional Epidemiology ◽  
Best Fitting ◽  
Heritability Estimates ◽  
Fitting Model ◽  
Dietary Indices ◽  
Health Parameters

AbstractA healthy diet is associated with the improvement or maintenance of health parameters, and several indices have been proposed to assess diet quality comprehensively. Twin studies have found that some specific foods, nutrients and food patterns have a heritable component; however, the heritability of overall dietary intake has not yet been estimated. Here, we compute heritability estimates of the nine most common dietary indices utilized in nutritional epidemiology. We analyzed 2590 female twins from TwinsUK (653 monozygotic [MZ] and 642 dizygotic [DZ] pairs) who completed a 131-item food frequency questionnaire (FFQ). Heritability estimates were computed using structural equation models (SEM) adjusting for body mass index (BMI), smoking status, Index of Multiple Deprivation (IMD), physical activity, menopausal status, energy and alcohol intake. The AE model was the best-fitting model for most of the analyzed dietary scores (seven out of nine), with heritability estimates ranging from 10.1% (95% CI [.02, .18]) for the Dietary Reference Values (DRV) to 42.7% (95% CI [.36, .49]) for the Alternative Healthy Eating Index (A-HEI). The ACE model was the best-fitting model for the Healthy Diet Indicator (HDI) and Healthy Eating Index 2010 (HEI-2010) with heritability estimates of 5.4% (95% CI [−.17, .28]) and 25.4% (95% CI [.05, .46]), respectively. Here, we find that all analyzed dietary indices have a heritable component, suggesting that there is a genetic predisposition regulating what you eat. Future studies should explore genes underlying dietary indices to further understand the genetic disposition toward diet-related health parameters.

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