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Sökning: WFRF:(Koposov Roman A.) > (2010-2014)

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1.
  • Smiljanic, R., et al. (författare)
  • The Gaia-ESO Survey: The analysis of high-resolution UVES spectra of FGK-type stars
  • 2014
  • Ingår i: Astronomy & Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 570
  • Tidskriftsartikel (refereegranskat)abstract
    • Context. The ongoing Gaia-ESO Public Spectroscopic Survey is using FLAMES at the VLT to obtain high-quality medium-resolution Giraffe spectra for about 10(5) stars and high-resolution UVES spectra for about 5000 stars. With UVES, the Survey has already observed 1447 FGK-type stars. Aims. These UVES spectra are analyzed in parallel by several state-of-the-art methodologies. Our aim is to present how these analyses were implemented, to discuss their results, and to describe how a final recommended parameter scale is defined. We also discuss the precision (method-to-method dispersion) and accuracy (biases with respect to the reference values) of the final parameters. These results are part of the Gaia-ESO second internal release and will be part of its first public release of advanced data products. Methods. The final parameter scale is tied to the scale defined by the Gaia benchmark stars, a set of stars with fundamental atmospheric parameters. In addition, a set of open and globular clusters is used to evaluate the physical soundness of the results. Each of the implemented methodologies is judged against the benchmark stars to define weights in three different regions of the parameter space. The final recommended results are the weighted medians of those from the individual methods. Results. The recommended results successfully reproduce the atmospheric parameters of the benchmark stars and the expected T-eff-log g relation of the calibrating clusters. Atmospheric parameters and abundances have been determined for 1301 FGK-type stars observed with UVES. The median of the method-to-method dispersion of the atmospheric parameters is 55K for T-eff, 0.13dex for log g and 0.07 dex for [Fe/H]. Systematic biases are estimated to be between 50-100 K for T-eff, 0.10-0.25 dex for log g and 0.05-0.10 dex for [Fe/H]. Abundances for 24 elements were derived: C, N, O, Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Mo, Ba, Nd, and Eu. The typical method-to-method dispersion of the abundances varies between 0.10 and 0.20 dex. Conclusions. The Gaia-ESO sample of high-resolution spectra of FGK-type stars will be among the largest of its kind analyzed in a homogeneous way. The extensive list of elemental abundances derived in these stars will enable significant advances in the areas of stellar evolution and Milky Way formation and evolution.
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2.
  • Donati, P., et al. (författare)
  • The Gaia-ESO Survey : Reevaluation of the parameters of the open cluster Trumpler 20 using photometry and spectroscopy
  • 2014
  • Ingår i: Astronomy and Astrophysics. - 0004-6361 .- 1432-0746. ; 561, s. A94-
  • Tidskriftsartikel (refereegranskat)abstract
    • Trumpler 20 is an old open cluster (OC) located toward the Galactic centre, at about 3 kpc from the Sun and similar to 7 kpc from the Galactic centre. Its position makes this cluster particularly interesting in the framework of the chemical properties of the Galactic disc because very few old OCs reside in the inner part of the disc. For this reason it has been selected as a cluster target of the Gaia-ESO Survey, and spectra of many stars in the main-sequence and red-clump phases are now available. Moreover, although it has been studied by several authors in the past, no consensus on the evolutionary status of Tr 20 has been reached. The heavy contamination of field stars (the line of sight of Tr 20 crosses the Carina spiral arm) complicates a correct interpretation. Another interesting aspect of the cluster is that it shows a broadened main-sequence turn-off and a prominent and extended red-clump, characteristics that are not easily explained by classical evolutionary models. Exploiting both spectroscopic information from the Gaia-ESO Survey (and the ESO archive) and literature photometry, we obtain a detailed and accurate analysis of the properties of the cluster. We make use of the first accurate metallicity measurement ever obtained from several spectra of red clump stars, and of cluster membership determination using radial velocities. According to the evolutionary models adopted, we find that Tr 20 has an age in the range 1.35-1.66 Gyr, an average reddening E(B - V) in the range 0.31-0.35 mag, and a distance modulus (m - M)(0) between 12.64 and 12.72 mag. The spectroscopic metallicity is [Fe/H] = +0.17 dex. We discuss the structural properties of the object and constrain possible hypotheses for its broadened upper main sequence by estimating the effect of differential reddening and its extended red clump.
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3.
  • Magrini, L., et al. (författare)
  • The Gaia-ESO Survey: Abundance ratios in the inner-disk open clusters Trumpler 20, NGC 4815, NGC 6705
  • 2014
  • Ingår i: Astronomy & Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 563
  • Tidskriftsartikel (refereegranskat)abstract
    • Context. Open clusters are key tools to study the spatial distribution of abundances in the disk and their evolution with time. Aims. Using the first release of stellar parameters and abundances of the Gaia-ESO Survey, we analyse the chemical properties of stars in three old/intermediate-age open clusters, namely NGC 6705, NGC 4815, and Trumpler 20, which are all located in the inner part of the Galactic disk at Galactocentric radius R-GC similar to 7 kpc. We aim to prove their homogeneity and to compare them with the field population. Methods. We study the abundance ratios of elements belonging to two different nucleosynthetic channels: alpha-elements and iron-peak elements. For each element, we analyse the internal chemical homogeneity of cluster members, and we compare the cumulative distributions of cluster abundance ratios with those of solar neighbourhood turn-off stars and of inner-disk/bulge giants. We compare the abundance ratios of field and cluster stars with two chemical evolution models that predict different alpha-enhancement dependences on the Galactocentric distance due to different assumptions on the infall and star-formation rates. Results. The main results can be summarised as follows: i) cluster members are chemically homogeneous within 3 sigma in all analysed elements; ii) the three clusters have comparable [El/Fe] patterns within similar to 1 sigma, but they differ in their global metal content [El/H] with NGC 4815 having the lowest metallicity; their [El/Fe] ratios show differences and analogies with those of the field population, in both the solar neighbourhood and the bulge/inner disk; iii) comparing the abundance ratios with the results of two chemical evolution models and with field star abundance distributions, we find that the abundance ratios of Mg, Ni, and Ca in NGC 6705 might require an inner birthplace, implying a subsequent variation in its R-GC during its lifetime, which is consistent with previous orbit determination. Conclusions. Using the results of the first internal data release, we show the potential of the Gaia-ESO Survey through a homogeneous and detailed analysis of the cluster versus field populations to reveal the chemical structure of our Galaxy using a completely uniform analysis of different populations. We verify that the Gaia-ESO Survey data are able to identify the unique chemical properties of each cluster by pinpointing the composition of the interstellar medium at the epoch and place of formation. The full dataset of the Gaia-ESO Survey is a superlative tool to constrain the chemical evolution of our Galaxy by disentangling different formation and evolution scenarios.
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4.
  • Stickley, Andrew, et al. (författare)
  • Binge drinking among adolescents in Russia : Prevalence, risk and protective factors
  • 2013
  • Ingår i: Addictive Behaviours. - 0306-4603 .- 1873-6327. ; 38:4, s. 1988-1995
  • Tidskriftsartikel (refereegranskat)abstract
    • Despite evidence that alcohol misuse has been having an increasingly detrimental effect on adolescent wellbeing in Russia in recent years this phenomenon has been little researched. Using data from 2112 children from the Arkhangelsk Social and Health Assessment (SAHA) 2003, this study examined which factors acted as 'risk' or 'protective' factors for adolescent binge drinking within three domains we termed the 'family environment', the 'alcohol environment' and 'deviant behaviour'. The results showed that in the presence of comparatively moderate levels of binge drinking among both boys and girls, being able to access alcohol easily, being unaware of the risks of binge drinking and having peers who consumed alcohol increased the risk of adolescent binge drinking - as did playing truant, smoking and marijuana use, while parental warmth was protective against binge drinking for girls. Our finding that risk and protective factors occur across domains suggests that any interventions targeted against adolescent binge drinking may need to simultaneously focus on risk behaviours in different domains, while at the same time, broader social policy should act to limit the availability of alcohol to adolescents in Russia more generally.
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5.
  • Grigorenko, Elena L., et al. (författare)
  • Aggressive Behavior, Related Conduct Problems, and Variation in Genes Affecting Dopamine Turnover
  • 2010
  • Ingår i: Aggressive Behavior. - 0096-140X .- 1098-2337. ; 36:3, s. 158-176
  • Tidskriftsartikel (refereegranskat)abstract
    • A number of dopamine-related genes have been implicated in the etiology of violent behavior and conduct problems. Of these genes, the ones that code for the enzymes that influence the turnover of dopamine (DA) have received the most attention. In this study, we investigated 12 genetic polymorphisms in four genes involved with DA functioning (COMT, MAOA and MAOB, and D beta H in 179 incarcerated male Russian adolescents and two groups of matched controls: boys without criminal records referred to by their teachers as (a) "troubled-behavior-free" boys, n = 182; and (b) "troubled-behavior" boys, n = 60. The participants were classified as (1) being incarcerated or not, (2) having the DSM-IV diagnosis of conduct disorder (CD) or not, and (3) having committed violent or nonviolent crimes (for the incarcerated individuals only). The findings indicate that, although no single genetic variant in any of the four genes differentiated individuals in the investigated groups, various linear combinations (i.e., haplotypes) and nonlinear combinations (i.e., interactions between variants within and across genes) of genetic variants resulted in informative and robust classifications for two of the three groupings. These combinations of genetic variants differentiated individuals in incarceration vs. nonincarcerated and CD vs. no-CD groups; no informative combinations were established consistently for the grouping by crime within the incarcerated individuals. This study underscores the importance of considering multiple rather than single markers within candidate genes and their additive and interactive combinations, both with themselves and with nongenetic indicators, while attempting to understand the genetic background of such complex behaviors as serious conduct problems.
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6.
  • Stickley, Andrew, et al. (författare)
  • Adolescent binge drinking and risky health behaviours : Findings from northern Russia.
  • 2013
  • Ingår i: Drug And Alcohol Dependence. - 0376-8716 .- 1879-0046. ; 133:15, s. 838-844
  • Tidskriftsartikel (refereegranskat)abstract
    • BACKGROUND: Some evidence suggests that in recent years the prevalence of heavy drinking has increased among Russian adolescents. However, as yet, little is known about either heavy alcohol consumption or its relationship with other adolescent health risk behaviours in Russia. The aim of this study therefore was to investigate the association between binge drinking and health risk behaviours among adolescents in Russia.METHODS: Data were drawn from the Social and Health Assessment (SAHA), a survey carried out in Arkhangelsk, Russia in 2003. Information was obtained from a representative sample of 2868 adolescents aged 13-17 regarding the prevalence and frequency of binge drinking (five or more drinks in a row in a couple of hours) and different forms of substance use, risky sexual behaviour and violent behaviour. Logistic regression analysis was used to examine the association between binge drinking and adolescent involvement in various health risk behaviours.RESULTS: Adolescent binge drinking was associated with the occurrence of every type of health risk behaviour - with the sole exception of non-condom use during last sex. In addition, there was a strong association between the number of days on which binge drinking occurred and the prevalence of many health risk behaviours.CONCLUSIONS: Binge drinking is associated with a variety of health risk behaviours among adolescents in Russia. Public health interventions such as reducing the affordability and accessibility of alcohol are now needed to reduce binge drinking and its harmful effects on adolescent well-being.
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7.
  • Stickley, Andrew, et al. (författare)
  • Loneliness and health risk behaviours among Russian and U.S. adolescents : a cross-sectional study.
  • 2014
  • Ingår i: BMC public health. - 1471-2458. ; 14, s. 366-
  • Tidskriftsartikel (refereegranskat)abstract
    • BACKGROUND: For some adolescents feeling lonely can be a protracted and painful experience. It has been suggested that engaging in health risk behaviours such as substance use and sexual behaviour may be a way of coping with the distress arising from loneliness during adolescence. However, the association between loneliness and health risk behaviour has been little studied to date. To address this research gap, the current study examined this relation among Russian and U.S. adolescents.METHODS: Data were used from the Social and Health Assessment (SAHA), a school-based survey conducted in 2003. A total of 1995 Russian and 2050 U.S. students aged 13-15 years old were included in the analysis. Logistic regression was used to examine the association between loneliness and substance use, sexual risk behaviour, and violence.RESULTS: After adjusting for demographic characteristics and depressive symptoms, loneliness was associated with a significantly increased risk of adolescent substance use in both Russia and the United States. Lonely Russian girls were significantly more likely to have used marijuana (odds ratio [OR]: 2.28; confidence interval [CI]: 1.17-4.45), while lonely Russian boys had higher odds for past 30-day smoking (OR, 1.87; CI, 1.08-3.24). In the U.S. loneliness was associated with the lifetime use of illicit drugs (excepting marijuana) among boys (OR, 3.09; CI, 1.41-6.77) and with lifetime marijuana use (OR, 1.79; CI, 1.26-2.55), past 30-day alcohol consumption (OR, 1.80; CI, 1.18-2.75) and past 30-day binge drinking (OR, 2.40; CI, 1.56-3.70) among girls. The only relation between loneliness and sexual risk behaviour was among Russian girls, where loneliness was associated with significantly higher odds for ever having been pregnant (OR, 1.69; CI: 1.12-2.54). Loneliness was not associated with violent behaviour among boys or girls in either country.CONCLUSION: Loneliness is associated with adolescent health risk behaviour among boys and girls in both Russia and the United States. Further research is now needed in both settings using quantitative and qualitative methods to better understand the association between loneliness and health risk behaviours so that effective interventions can be designed and implemented to mitigate loneliness and its effects on adolescent well-being.
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8.
  • DeYoung, Colin G., et al. (författare)
  • Variation in the catechol-O-methyltransferase Val(158)Met polymorphism associated with conduct disorder and ADHD symptoms, among adolescent male delinquents
  • 2010
  • Ingår i: Psychiatric Genetics. - 0955-8829 .- 1473-5873. ; 20:1, s. 20-24
  • Tidskriftsartikel (refereegranskat)abstract
    • Objective Variation in the catechol-O-methyltransferase gene (COMT) has been associated with antisocial behavior in populations with attention deficit/hyperactivity disorder (ADHD). This study examined whether COMT would predict antisocial behavior in a sample with high levels of behavior problems, not necessarily ADHD. In addition, because previous research suggests that COMT may be associated with ADHD in males, association between COMT and ADHD symptoms was examined. Method This study tested whether variation in three polymorphisms of the COMT gene was predictive of symptoms of conduct disorder and ADHD, in a sample of 174 incarcerated Russian adolescent male delinquents. Results The Val allele of the Val(158)Met polymorphism was significantly associated with conduct disorder diagnosis and symptoms, whereas the Met allele was associated with ADHD symptoms. Conclusion The Val(158)Met polymorphism of the COMT gene shows a complex relation to behavior problems, influencing conduct disorder and ADHD symptoms in opposite directions in a high-risk population. Psychiatr Genet 20:20-24 (C) 2010 Wolters Kluwer Health vertical bar Lippincott Williams & Wilkins.
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9.
  • Grigorenko, Elena L., et al. (författare)
  • Aggressive behaviour, related conduct problems, and variation in genes affecting dopamine turnover
  • 2010
  • Ingår i: Aggressive Behavior. - 0096-140X .- 1098-2337. ; 36:3, s. 158-176
  • Tidskriftsartikel (refereegranskat)abstract
    • A number of dopamine-related genes have been implicated in the etiology of violent behavior and conduct problems. Of these genes, the ones that code for the enzymes that influence the turnover of dopamine (DA) have received the most attention. In this study, we investigated 12 genetic polymorphisms in four genes involved with DA functioning (COMT, MAOA and MAOB, and DβH) in 179 incarcerated male Russian adolescents and two groups of matched controls: boys without criminal records referred to by their teachers as (a) “troubled-behavior-free” boys, n=182; and (b) “troubled-behavior” boys, n=60. The participants were classified as (1) being incarcerated or not, (2) having the DSM-IV diagnosis of conduct disorder (CD) or not, and (3) having committed violent or nonviolent crimes (for the incarcerated individuals only). The findings indicate that, although no single genetic variant in any of the four genes differentiated individuals in the investigated groups, various linear combinations (i.e., haplotypes) and nonlinear combinations (i.e., interactions between variants within and across genes) of genetic variants resulted in informative and robust classifications for two of the three groupings. These combinations of genetic variants differentiated individuals in incarceration vs. nonincarcerated and CD vs. no-CD groups; no informative combinations were established consistently for the grouping by crime within the incarcerated individuals. This study underscores the importance of considering multiple rather than single markers within candidate genes and their additive and interactive combinations, both with themselves and with nongenetic indicators, while attempting to understand the genetic background of such complex behaviors as serious conduct problems.
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10.
  • Wiklund, Gunnar, et al. (författare)
  • Pro-bullying attitudes among incarcerated juvenile delinquents : Antisocial behavior, psychopathic tendencies and violent crime
  • 2014
  • Ingår i: International Journal of Law and Psychiatry. - New York : Pergamon Press. - 0160-2527 .- 1873-6386. ; 37:3, s. 281-288
  • Tidskriftsartikel (refereegranskat)abstract
    • The objective was to evaluate a new scale aimed at assessing antisocial attitudes, the Pro-bullying Attitude Scale (PAS), on a group of 259 voluntarily-recruited male juvenile delinquents from a juvenile correctional institution in Arkhangelsk, North-western Russia. Exploratory factor analysis gave a two-factor solution: Factor 1 denoted Callous/Dominance and Factor 2 denoted Manipulativeness/Impulsiveness. Subjects with complete data on PAS and Childhood Psychopathy Scale (CPS) (n = 171) were divided into extreme groups (first and fourth quartiles) according to their total scores on PAS and the two factor scores, respectively. The extreme groups of total PAS and PAS Factor 1 differed in CPS ratings and in violent behavior as assessed by the Antisocial Behavior Checklist (ABC). They also differed in the personality dimension Harm Avoidance as measured by use of the Temperament and Character Inventory (TCI), and in delinquent and aggressive behavior as assessed by the Youth Self Report (YSR). The extreme groups of PAS Factor 2, in turn, differed in aggressive behavior as assessed by the YSR, and in the TCI scale Self-Directedness. When PAS was used as a continuous variable, total PAS and PAS Factor 1 (Callous/Dominance) were significantly positively related to registered violent crime. The possible usefulness of PAS in identifying high-risk individuals for bullying tendencies among incarcerated delinquents is discussed.
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